WO2019203321A1 - Developing member, process cartridge, and electrophotography apparatus - Google Patents

Developing member, process cartridge, and electrophotography apparatus Download PDF

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Publication number
WO2019203321A1
WO2019203321A1 PCT/JP2019/016693 JP2019016693W WO2019203321A1 WO 2019203321 A1 WO2019203321 A1 WO 2019203321A1 JP 2019016693 W JP2019016693 W JP 2019016693W WO 2019203321 A1 WO2019203321 A1 WO 2019203321A1
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WO
WIPO (PCT)
Prior art keywords
domain
conductive layer
conductive
developing member
developing
Prior art date
Application number
PCT/JP2019/016693
Other languages
French (fr)
Japanese (ja)
Inventor
真樹 山田
裕一 菊池
哲男 日野
一浩 山内
匠 古川
渡辺 宏暁
健哉 寺田
雄也 友水
俊光 中澤
Original Assignee
キヤノン株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2019032936A external-priority patent/JP7229811B2/en
Application filed by キヤノン株式会社 filed Critical キヤノン株式会社
Priority to CN201980026505.6A priority Critical patent/CN111989622B/en
Publication of WO2019203321A1 publication Critical patent/WO2019203321A1/en
Priority to US17/070,712 priority patent/US11112748B2/en

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/15Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor incorporating preformed parts or layers, e.g. extrusion moulding around inserts
    • B29C48/154Coating solid articles, i.e. non-hollow articles
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C13/00Rolls, drums, discs, or the like; Bearings or mountings therefor
    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03GELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00Apparatus for electrographic processes using a charge pattern
    • G03G15/06Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer

Definitions

  • the present invention relates to a developing member used in an electrophotographic apparatus, a process cartridge having the developing member, and an electrophotographic apparatus.
  • a developing member such as a developing roller, a toner supply roller, and a developing blade
  • a conductive material having an electrical resistance value such as 1 ⁇ 10 5 to 1 ⁇ 10 12 ⁇
  • a developing member having a layer is used.
  • an electron conductive agent such as carbon black or an ionic conductive agent such as a quaternary ammonium salt has been used for imparting conductivity to a conductive layer and forming a stable conductive mechanism.
  • the developing member is required to have various functions such as toner conveyance to an electrophotographic photoreceptor (hereinafter referred to as “photoreceptor”), charge application to the toner, difficulty in surface contamination, and the like.
  • Photoreceptor an electrophotographic photoreceptor
  • Countermeasures are disclosed.
  • Patent Document 1 discloses a method for improving toner releasability and wear by using a roll-shaped developer carrier having a continuous phase and a discontinuous phase on the surface.
  • Patent Document 2 discloses a method of reducing discharge unevenness by having a sea-island structure in which a surface layer of a conductive member includes a non-conductive sea part and an island part containing an electronic conductive agent.
  • an electrophotographic apparatus is required to maintain high image quality and high durability even in a high-speed process in a harsh environment.
  • an electronic conductive agent such as carbon black
  • the conductivity is manifested by the movement of charges through the conductive path where the electronic conductive agent is connected from the conductive support to the surface of the conductive member.
  • this conductive path is responsible for transporting the electric charge consumed by energization, it takes a certain time until the electric charge is supplied for the next energization. That is, in the high-speed process, when the supply of the charge applied to the toner cannot follow the process speed, the amount of charge applied to the toner varies. This makes it difficult to achieve uniform development.
  • a fogged image in which toner having a low charge amount appears in the image may occur.
  • a conductive member that exhibits conductivity by dispersing an ionic conductive agent in the conductive layer exhibits conductivity when anions and cations such as quaternary ammonium move. Therefore, in a high-speed process, when the movement speed of anions and cations is slow, the process speed cannot be followed, and as described above, the charge supply to the toner for the next development is insufficient and a fog image is generated. was there.
  • the process of charge movement in the conductive path and the process of applying charge to the toner can be estimated as follows. First, a voltage is applied to a conductive support connected to a power source, and electric charges are supplied.
  • This electric charge is transported (supplied) through the conductive layer of the conductive member to the surface of the developing member.
  • the charge on the surface of the developing member moves to the toner, that is, the charge is supplied to the toner.
  • the charge on the surface of the developing member decreases by the amount transferred to the toner, but as long as the conductive support of the developing member is connected to the power source, new charge is supplied to the surface of the developing member through the conductive support. Is done. In this way, new charges are continuously supplied to the developing member, so that the charge can be continuously supplied to the toner.
  • toner particles form a toner layer having a thickness of about 2 to 3 on the surface of the toner carrier and are developed onto a photoreceptor.
  • the toner is supplied with electric charge from the toner carrying member within a very short time passing between the toner carrying member and the developing blade while being rolled. Therefore, if the supply of charge to the developing member stagnate and the charge transfer speed of the conductive layer of the developing member is slow, the amount of new charge supplied to the surface of the developing member is limited.
  • the present invention is directed to providing an electrophotographic developing member capable of maintaining high image quality and high durability even in a high-speed process.
  • the present invention is also directed to providing an electrophotographic apparatus capable of stably outputting high-quality electrophotographic images and a process cartridge used therefor.
  • a developing member for electrophotography having a support having a conductive outer surface and a conductive layer provided on the outer surface of the support, the conductive layer comprising: A matrix including a first rubber; and a plurality of domains dispersed in the matrix, the domain including a second rubber and an electronic conductive agent, and a metal film on the outer surface of the developing member.
  • the slope at 7 Hz is -0.8 or more and -0.3 or less
  • a developing member having an impedance at a frequency of 1.0 ⁇ 10 ⁇ 2 Hz to 1.0 ⁇ 10 0 Hz is 1.0 ⁇ 10 4 ⁇ to 1 ⁇ 10 11 ⁇ .
  • a process cartridge configured to be detachable from a main body of an electrophotographic apparatus, the process cartridge including the developing member. Furthermore, according to another aspect of the present invention, there is provided an electrophotographic apparatus comprising the above process cartridge.
  • an electrophotographic developing member capable of maintaining high image quality and high durability even in a high-speed process is obtained.
  • an electrophotographic apparatus capable of stably outputting a high-quality electrophotographic image and a process cartridge used therefor are obtained.
  • 1 is a schematic cross-sectional view of an electrophotographic developing roller according to an embodiment of the present invention.
  • 1 is a schematic cross-sectional view of an electrophotographic developing blade according to an embodiment of the present invention. It is explanatory drawing of the graph which shows the relationship between an impedance characteristic and a frequency. It is explanatory drawing of the behavior of an impedance. It is sectional drawing perpendicular
  • the inventors of the present invention have intensively studied to achieve the above object.
  • the charge that leads to imparting charge to toner is transported from a conductive support to which a voltage is applied to the surface of the developing member to form a potential on the surface of the developing member.
  • the conductive mechanism for transporting the charge is a conductive path of an electronic conductive agent such as carbon black or a conductive path of an ionic conductive agent.
  • the toner is usually carried on the surface of the developing member as a toner layer having a thickness of two to three, and is supplied with electric charge when it contacts with the developing member while rolling.
  • the contact area between the toner and the developing member has a certain area. Within this area, the toner is charged several times. For example, when the developing device has a developing roller and a developing blade, the toner is charged several times while passing through the contact area with the developing blade by rotation of the developing roller and rolling of the toner. It has occurred.
  • the charge supply supplied from the surface of the developing member lasts for a certain time, and the charge transported to the surface of the developing member is consumed.
  • the charge application is completed, the consumed charge is supplied again from the conductive path inside the developing member to the surface of the developing member, and the next charge application occurs. Therefore, the final charge amount of the toner is considered to be an accumulation of the applied charge amount for a plurality of times.
  • the toner environment and the development history affect the electric field at the contact portion with the surface of the developing member, and the amount of applied charge is also affected. Have.
  • the first charge application immediately after entering the development nip region formed by the photosensitive member and the development member has a sufficient amount of charge, but the subsequent charge supply for charge application is not possible. It may not be possible to follow.
  • the developing member includes a support having a conductive outer surface, a conductive layer provided on the outer surface of the support, the conductive layer including a first rubber, and a matrix in the matrix. A plurality of dispersed domains, the domains including a second rubber and an electronic conductive agent.
  • the developing member is provided with a metal film on its outer surface, and an AC voltage having an amplitude of 1 V is applied between the outer surface of the support and the metal film in an environment of a temperature of 23 ° C.
  • Impedance was measured by applying the voltage while changing between 1.0 ⁇ 10 ⁇ 2 Hz and 1.0 ⁇ 10 7 Hz, and the following logarithmic plots were made with the frequency plotted on the horizontal axis and the impedance plotted on the vertical axis. Satisfy both the first and second requirements.
  • the developing member according to this aspect is not limited to the developing roller, and can be applied to, for example, a developing blade and a toner supply roller.
  • the developing member according to this aspect includes a support having a conductive outer surface, and a conductive layer provided on the outer surface of the support.
  • the conductive layer has conductivity.
  • the conductivity is defined as having a volume resistivity of less than 1.0 ⁇ 10 8 ⁇ ⁇ cm.
  • the conductive layer has a matrix including a first rubber and a plurality of domains dispersed in the matrix, and the domains include a second rubber and an electronic conductive agent. Further, the developing member satisfies the above ⁇ first requirement> and ⁇ second requirement>.
  • the first requirement stipulates that charge stagnation does not easily occur in the developing member on the high frequency side.
  • the slope is always ⁇ 1 on the high frequency side.
  • the inclination is an inclination with respect to the horizontal axis when the impedance characteristic of the developing member is log-log plotted against the frequency as shown in FIG.
  • the equivalent circuit of the developing member is represented by a parallel circuit of an electric resistance R and a capacitance C, and the absolute value
  • f in Formula (1) shows a frequency.
  • Equation (1) On the high frequency side, the impedance slope becomes a straight line of ⁇ 1 because the movement of electric charges cannot follow the high frequency voltage and stagnates, so that the electric resistance value R has greatly increased. It can be estimated that the capacity is being measured. It can be estimated that the state in which the charge is stagnated is a state in which R is approximated to infinity in Equation (1).
  • Expression (2) in which the denominator element is extracted, an approximation is possible in which R- 2 takes a very small value with respect to (2 ⁇ f) 2 C 2 . Therefore, equation (1) can be modified by approximation such as equation (3) with R -2 removed.
  • FIG. 4 shows the behavior of the impedance expressed by Equation (1).
  • the absolute value of the impedance satisfying the equation (1) decreases as the frequency increases.
  • the decreasing behavior is a slope of ⁇ 1 without depending on the electric resistance value or capacitance of the developing member, as shown by the equation (4). It becomes a straight line.
  • the impedance characteristic of the insulating developing member is measured, the slope becomes a straight line of ⁇ 1.
  • the developing member having a charge of ⁇ 0.8 or more and ⁇ 0.3 or less is charged on the high frequency side.
  • Supply is difficult to stagnate.
  • the range of the high frequency region is considered to be a region where variations in the charge supply to the toner are likely to occur because the current is supplied in the region having the highest frequency among the charge supply frequencies generated from the developing member.
  • the developing member has the characteristic of suppressing the variation in the charge supply to the toner. It is done.
  • ⁇ Second requirement> The impedance on the low frequency side according to the second requirement represents a characteristic that the stagnation of charges is difficult to occur. This can also be seen from the region where the slope of impedance on the low frequency side is not -1.
  • Equation (1) when the frequency is approximated to zero, it can be approximated to the electric resistance value R. Therefore, it can be seen that the electric resistance value R represents the ability to move the charges in a single direction. Therefore, in the measurement while applying a low-frequency voltage, it can be assumed that the amount of charge movement in a state where the movement of the charge can follow the vibration of the voltage is simulated. The amount of charge movement at a low frequency is an indicator of the ease of charge transfer between the developing member and the measurement electrode.
  • the charge can be transferred from the surface of the developing member to the toner by energization. It can be an indicator of quantity.
  • the AC voltage used for the impedance measurement according to the first requirement and the second requirement has an amplitude of 1V.
  • the vibration voltage for measurement is much lower than the voltage actually applied to the developing member in the electrophotographic image forming apparatus is several hundred volts to several thousand volts. Therefore, it is considered that the ease of charge generation from the surface of the developing member can be evaluated in a higher dimension by measuring the impedance according to the first requirement and the second requirement.
  • the impedance is lower than 1.0 ⁇ 10 4 ⁇ , the amount of charge supplied at one time becomes too large, and the supply of charge for the next charge supply cannot follow and the variation in charge supply occurs. It becomes difficult to work and suppress fogging.
  • the impedance exceeds 1.0 ⁇ 10 11 ⁇ , the easiness of generating a charge is reduced, and the amount of energization until the charge supply variation is filled is not reached. As described with reference to FIG.
  • the absolute value of the impedance takes a constant value, and the impedance at 1.0 ⁇ 10 ⁇ 2 Hz to 1.0 ⁇ 10 0 Hz is For example, an impedance value at a frequency of 1 Hz can be substituted.
  • the developing member satisfying both the first requirement and the second requirement can suppress the variation in the charge supply to the toner in the frequency range from the low frequency side to the high frequency side and reduce the fog.
  • the first requirement variation in charge supply on the high frequency side can be suppressed.
  • the second requirement the amount of supplied charge can be further improved, and the generation of fog can be effectively suppressed.
  • the impedance of the developing member can be measured by the following method.
  • a low-resistance thin film is deposited on the surface of the developing member, and the thin film is used as an electrode while conducting support is supported. It is preferable to measure impedance with two terminals using the body as a ground electrode.
  • the method for forming the thin film include metal film forming methods such as metal vapor deposition, sputtering, application of metal paste, and application of metal tape.
  • a method of forming a metal thin film such as platinum or palladium as an electrode by vapor deposition is preferable.
  • a mechanism capable of gripping the developing member is given to the vacuum deposition apparatus, and the developing member having a cylindrical cross section is provided. It is preferable to use a vacuum deposition apparatus to which a rotation mechanism is further added.
  • a metal sheet that is wound without any gap in the circumferential direction of the developing member it is preferable to use a metal sheet that is wound without any gap in the circumferential direction of the developing member. Thereby, impedance measurement can be carried out without being affected by the fluctuation of the outer edge size (outer diameter in the case of a cylindrical developing member) or the surface shape in a cross section orthogonal to the longitudinal direction of the developing member.
  • the metal sheet aluminum foil, metal tape, or the like can be used.
  • the impedance measuring device may be any device that can measure impedance in a frequency region up to 10 7 Hz, such as an impedance analyzer, a network analyzer, and a spectrum analyzer. Among these, it is preferable to measure with an impedance analyzer from the electric resistance region of the developing member.
  • the impedance measurement conditions will be described. Using an impedance measurement device, the impedance in the frequency region of 1.0 ⁇ 10 ⁇ 2 Hz to 1.0 ⁇ 10 7 Hz is measured. The measurement is performed in an environment at a temperature of 23 ° C. and a relative humidity of 50%. In order to reduce measurement variation, five or more measurement points are provided for each digit of the frequency, and the oscillating voltage is 1 Vpp.
  • the measurement voltage may be measured while applying a DC voltage in consideration of a shared voltage applied to the developing member in the electrophotographic apparatus. Specifically, measurement while applying a DC voltage of 10 V or less to the vibration voltage is suitable for quantifying the charge transport and accumulation characteristics.
  • a method for calculating the slope of impedance will be described.
  • the absolute value of the impedance is plotted in a log-log graph with respect to the measurement frequency using a spreadsheet software such as Windows Excel (registered trademark).
  • the slope of the absolute value of the impedance in the frequency region of 1.0 ⁇ 10 6 Hz to 1.0 ⁇ 10 7 Hz of the graph obtained by this log-log plot is 1.0 ⁇ 10 6 Hz to 1.0 ⁇ .
  • an approximate straight line of a linear function may be calculated by a least square method with respect to a plot of the graph in the frequency range, and the slope may be calculated.
  • the arithmetic average value at the measurement point in the frequency region of 1.0 ⁇ 10 ⁇ 2 Hz to 1.0 ⁇ 10 0 Hz in the log-log graph is calculated, and the obtained value is used as the low frequency input impedance.
  • the slope of the impedance if the longitudinal direction of the developing member is divided into five equal parts, the measurement is performed at five locations in each area, and the arithmetic average of the measured values at the five locations is calculated. Good.
  • the developing member for electrophotography has a conductive support and at least one conductive layer on the support.
  • a roller-shaped developing member (developing roller) is shown in FIG.
  • a developing roller 1A shown in FIG. 1 includes a conductive support 2 and a conductive layer 3 provided on an outer peripheral surface (outer surface) thereof.
  • the conductive layer 3 is provided directly on the support 2 as the only layer of the developing roller 1A. It is preferable that The configuration of the layer of the developing roller 1A is not limited to the form shown in FIG. As another form of the developing roller 1A, as shown in FIG.
  • FIG. 5 is a schematic cross-sectional view of the developing blade 1B.
  • a developing blade 1B shown in FIG. 2 includes a conductive support 2 and a conductive layer 3 provided in a partial region including an end portion of the outer surface of the support 2.
  • the developing blade 1B has a configuration in which the conductive layer 3 is coated on the leading end of a conductive stainless steel sheet that is a part of the support, and the trailing end of the stainless steel sheet is welded to the conductive support 2.
  • You can also The developing member can be used for a developing roller, a developing sleeve, a developing blade, and a toner supply roller.
  • the conductive support 2 functions as a support member for the developing member and, in some cases, an electrode.
  • the support when the developing member has a roller shape, the support 2 has a solid columnar shape or a hollow cylindrical shape, and when the developing member has a blade shape, the support 2 has a thin plate shape.
  • the material constituting the conductive support can be appropriately selected from materials known in the field of electrophotographic conductive members and materials usable as such developing members. As an example, metals or alloys such as aluminum, stainless steel, carbon steel alloys, conductive synthetic resins, iron, copper alloys, and the like can be given.
  • plating thickness is preferably 0.05 ⁇ m or more, and the plating thickness is preferably 0.1 ⁇ m to 30 ⁇ m in consideration of the balance between work efficiency and rust prevention ability. If a medium resistance layer or an insulating layer exists between the support and the conductive layer, it becomes impossible to quickly supply the charge after the charge is consumed by energization.
  • a primer a well-known thing can be selected and used according to the rubber material for conductive layer formation, the material of a support body, etc.
  • the primer material include thermosetting resins and thermoplastic resins. Specifically, materials such as phenol resins, urethane resins, acrylic resins, polyester resins, polyether resins, and epoxy resins can be used.
  • the impedance of the resin layer and the support is in the range of 1.0 ⁇ 10 ⁇ 5 ⁇ to 1.0 ⁇ 10 1 ⁇ at a frequency of 1.0 ⁇ 10 ⁇ 2 Hz to 1.0 ⁇ 10 0 Hz. Is preferred. If the support and the resin layer have a low frequency impedance within the above range, a sufficient charge can be supplied to the conductive layer, and the discharge according to the first and second requirements of the matrix domain structure contained in the conductive layer. This is preferable because the function of suppressing the omission is not hindered.
  • the impedance of the resin layer can be measured by the same method as the measurement of the impedance slope described above, except that the conductive layer existing on the outermost surface is peeled off.
  • the impedance of the support is as described above in a state before coating the resin layer or the conductive layer, or after the development roller is formed, in a state where the conductive layer or the coating layer made of the resin layer and the conductive layer is peeled off. It can be measured by the same method as the impedance measurement.
  • ⁇ Conductive layer> As the developing member that satisfies the ⁇ first requirement> and the ⁇ second requirement>, for example, a developing member in which the conductive layer satisfies at least one of the following configurations (i) to (iii) is preferable.
  • the volume resistivity of the matrix is greater than 1.0 ⁇ 10 12 ⁇ ⁇ cm and 1.0 ⁇ 10 17 ⁇ ⁇ cm or less.
  • the volume resistivity of the domain is 1.0 ⁇ 10 1 ⁇ ⁇ cm or more and 1.0 ⁇ 10 4 ⁇ ⁇ cm or less.
  • the distance between adjacent wall surfaces of the domain is in the range of 0.2 ⁇ m or more and 2.0 ⁇ m or less.
  • FIG. 6 shows a partial cross-sectional view of the conductive layer in a direction perpendicular to the longitudinal direction of the conductive roller.
  • the conductive layer 6 has a matrix-domain structure having a matrix 6a and a domain 6b.
  • the domain 6b includes an electronic conductive agent 6c as an electronic conductive agent.
  • the volume resistivity of the matrix is set to 1.0 ⁇ in order to suppress the occurrence of simultaneous charge transfer between domains during bias application and to accumulate sufficient charges in the domains.
  • the volume resistivity of the domain is 1.0 ⁇ 10 1 ⁇ ⁇ cm or more, 1.0 ⁇ 10 4 ⁇ ⁇ cm or less (configuration (ii)) and at least a distance between adjacent wall surfaces between domains within a range of 0.2 ⁇ m or more and 2.0 ⁇ m or less (configuration (iii)) It is preferable to satisfy one.
  • ⁇ first requirement> in order to move charges through a domain in a conductive layer even under application of a high frequency bias, a region (domain) in which charges are sufficiently accumulated is electrically insulating.
  • the present inventors consider that the structure divided by the region (matrix) is effective. Then, by setting the volume resistivity of the matrix within the range of the high resistance region as described above, sufficient charges can be retained at the interface with each domain, and charge leakage from the domain can be suppressed. Further, the present inventors have found that in order to obtain a conductive layer that satisfies the ⁇ second requirement>, it is effective to limit the charge transfer path to a path through a domain. By suppressing the leakage of charge from the domain to the matrix and limiting the charge transport path to the path through multiple domains, the density of charges existing in the domain can be improved. The filling amount can be further increased.
  • the total number of charges that can be involved in energization can be improved on the surface of the domain as the conductive phase, which is the starting point of energization, and as a result, the ease with which charges are generated from the surface of the developing member can be improved. it is conceivable that.
  • the volume resistivity of the matrix can be measured by thinning the developing member and using a microprobe.
  • the thinning means include a sharp razor, a microtome, and a focused ion beam method (FIB).
  • FIB focused ion beam method
  • SEM scanning electron microscope
  • TEM transmission electron microscope
  • a thinning means a means capable of producing a very thin sample such as a microtome is preferable.
  • the volume resistivity is measured by first grounding one side of the slice and then specifying the location of the matrix and domain in the slice.
  • means capable of measuring the volume resistivity or hardness distribution of the matrix and the domain with a scanning probe microscope (SPM), an atomic force microscope (AFM) or the like can be used.
  • SPM scanning probe microscope
  • AFM atomic force microscope
  • a probe is brought into contact with the matrix, and a ground current when a DC voltage of 10 V is applied is measured and calculated as an electric resistance.
  • any means capable of measuring the shape such as SPM or AFM of the thin piece is preferable because the film thickness of the thin piece can be measured and the volume resistivity can be measured.
  • the measurement of the volume resistivity of the matrix in the cylindrical developing member was performed by cutting out a thin sample one by one from each of the regions obtained by dividing the conductive layer into 4 parts in the circumferential direction and 5 parts in the longitudinal direction, and obtained the above measured values. Later, this can be done by calculating the arithmetic mean value of the volume resistivity of a total of 20 samples.
  • the volume resistivity of the domain is preferably 1.0 ⁇ 10 1 ⁇ ⁇ cm or more and 1.0 ⁇ 10 4 ⁇ ⁇ cm or less.
  • the volume resistivity of the domain is more preferably 1.0 ⁇ 10 2 ⁇ ⁇ cm or less.
  • the volume resistivity of the domain is adjusted by setting the conductivity to a predetermined value by using a conductive agent for the rubber component of the domain.
  • a rubber composition containing a rubber component for the matrix can be used, but a difference in solubility parameter (SP value) from the rubber material forming the matrix in order to form a matrix domain structure.
  • the volume resistivity of the domain can be adjusted by appropriately selecting the type of electronic conductive agent and the amount of addition thereof.
  • a conductive agent used for controlling the volume resistivity of the domain to 1.0 ⁇ 10 1 ⁇ ⁇ cm or more and 1.0 ⁇ 10 4 ⁇ ⁇ cm or less, the volume from high resistance to low resistance is varied depending on the amount of dispersion.
  • An electronic conductive agent capable of greatly changing the resistivity is preferable.
  • Examples of the electronic conductive agent blended in the domain include oxides such as carbon black, graphite, titanium oxide, and tin oxide; metals such as Cu and Ag; and particles that are conductively coated with oxide or metal on the surface As mentioned. Moreover, you may mix
  • the type of carbon black blended in the domain is not particularly limited. Specific examples include gas furnace black, oil furnace black, thermal black, lamp black, acetylene black, and ketjen black.
  • DBP oil absorption of 40 cm 3/100 g or more can be suitably used conductive carbon black is not more than 170cm 3 / 100g.
  • the electronic conductive agent such as conductive carbon black is preferably blended in the domain at 20 to 150 parts by mass with respect to 100 parts by mass of the rubber component contained in the domain.
  • a particularly preferable blending ratio is 50 parts by mass or more and 100 parts by mass or less. In the blending of the conductive agent at these ratios, it is preferable that a large amount of the conductive agent is blended as compared with a general electrophotographic conductive member.
  • the volume resistivity of the domain can be easily controlled in the range of 1.0 ⁇ 10 1 ⁇ ⁇ cm or more and 1.0 ⁇ 10 4 ⁇ ⁇ cm or less.
  • An ionic conductive agent may be used in combination with an electronic conductive agent as a conductive agent used for the domain.
  • an ionic conductive agent for example, a quaternary ammonium salt, an imidazolium salt, a pyridinium salt, or the like can be used.
  • anion of the ionic conductive agent examples include perchlorate anion, fluoroalkylsulfonylimide anion, fluorosulfonylimide anion, trifluoromethanesulfonate anion, tetrafluoroborate anion, and the like. At least one of these can be used.
  • a colorant and the like may be added to the rubber composition for a domain as long as the effects according to the present invention are not impaired.
  • -Measuring method of volume resistivity of the domain The volume resistivity of the domain is measured except that the measurement location is changed to a location corresponding to the domain, and the applied voltage at the time of measuring the current value is changed to 1 V, in contrast to the volume resistivity measurement method of the matrix. May be carried out in the same manner.
  • the volume resistivity of the domain is preferably uniform.
  • the arithmetic average value Dm of the distance between domains is preferably 0.2 ⁇ m or more and 2.0 ⁇ m or less.
  • the arithmetic average value Dm of the distance is preferably 2.0 ⁇ m or less, and more preferably 1.0 ⁇ m or less.
  • the arithmetic average value Dm of the inter-domain distance is 0.2 ⁇ m or more, particularly 0.3 ⁇ m or more. It is preferable to do.
  • ⁇ Measuring method of distance between domains What is necessary is just to implement the measuring method of the distance between domains as follows. First, a slice is prepared by the same method as that used in the measurement of the volume resistivity of the matrix. Next, a fracture surface is formed by means such as a freezing cleaving method, a cross polisher method, or a focused ion beam method (FIB).
  • FIB focused ion beam method
  • the FIB method is preferable in consideration of the smoothness of the fracture surface and pretreatment for observation. Further, in order to preferably observe the matrix domain structure, a pretreatment such as a dyeing treatment or a vapor deposition treatment that can suitably obtain the contrast between the conductive phase and the insulating phase may be performed.
  • the section subjected to the formation of the fracture surface and the pretreatment is observed with a scanning electron microscope (SEM) or a transmission electron microscope (TEM) to confirm the presence of the matrix domain structure.
  • SEM scanning electron microscope
  • TEM transmission electron microscope
  • the distance between domains is preferably measured by quantifying a photographed image of a fracture surface where a matrix-domain structure appears.
  • An image processing software (for example, “Luzex” (trade name, manufactured by Nireco)) is used for the fracture surface image obtained by observation with the SEM, and the gray scale is converted to 8-bit monochrome. Get an image. Next, the black and white of the image is inverted so that the domain in the fracture surface becomes white, and binarization is performed. Next, the distance between the wall surfaces of the domain size group in the image is calculated. The distance between the wall surfaces at this time is the shortest distance between adjacent domains. In the case of a cylindrical developing member, when the length of the conductive layer in the longitudinal direction is L and the thickness of the conductive layer is T, the length in the longitudinal direction of the conductive layer and the distance from both ends of the conductive layer toward the center are L.
  • a cross section in the thickness direction of the conductive layer as shown in FIG. For each of the obtained cross-sections, 50 ⁇ m square observation regions were placed at any three locations in the thickness region from the outer surface of the conductive layer to the depth of 0.1 T to 0.9 T in the direction of the support. What is necessary is just to measure the distance between each domain observed in each of the observation regions. Since the slice needs to observe the surface including the outer surface of the conductive layer from the support in the direction of charge movement, a cross section including the normal line starting from the central axis of the support can be observed. Cut out by direction. Note that the thickness T of the conductive layer is preferably 100 ⁇ m or more.
  • the distribution of the inter-domain distance is uniform.
  • the distribution of the distance between domains is uniform, so that a portion where the distance between domains is locally long in the conductive layer can be partially created, resulting in a charge stagnation when there is a place where charge supply is delayed compared to the surroundings. It is possible to reduce the phenomenon that the ease of taking out is suppressed.
  • the cross section where the charge is transported that is, the cross section in the thickness direction of the conductive layer as shown in FIG.
  • the thickness region from the outer surface of the conductive layer to the depth of 0.1T to 0.9T from the outer surface of the conductive layer When an observation area of 50 ⁇ m square at any three locations is acquired, ⁇ m / Dm is 0 or more using the arithmetic average value Dm of the interdomain distance in the observation area and the variation ⁇ m of the interdomain distance. .4 or less is preferable.
  • ⁇ Method for controlling the distance between domains> A method for controlling the distance between domains will be described below.
  • the interdomain distance is mainly (A) the volume ratio of the domain phase, (B) Viscosity ratio of domain to matrix (C) shear rate, (D) It is possible to control by the magnitude of the domain phase cutting energy.
  • the following method can be used to reduce the distance between domains. -Reduce the interfacial tension between the domain polymer and the matrix polymer. Reduce the viscosity difference between the domain polymer and the matrix polymer. Increase the shear rate during kneading / increase the energy during shearing. -Increase the volume ratio of the domain phase. ⁇ Lower the collision coalescence probability.
  • the control of the interdomain distance proceeds simultaneously with the control of the domain size, but the control of the interdomain distance is independently performed by controlling the volume ratio of the domain phase and the collision coalescence probability, that is, the kneading time and shear rate. Is possible.
  • conductive domains with uniform electrical resistance are arranged in a conductive layer three-dimensionally uniformly and densely. More preferably, the conductive path has no unevenness.
  • the average value of the ratio of the cross-sectional area of the portion made of conductive particles included in each domain to the cross-sectional area of each domain appearing in the cross section in the thickness direction of the conductive layer is ⁇ , and the standard of the ratio When the deviation is ⁇ , ⁇ / ⁇ is preferably 0 or more and 0.4 or less, and ⁇ is preferably 20% or more and 40% or less.
  • ⁇ and ⁇ at least 8 sample cubes out of a total of 9 sample cubes each having a side of 9 ⁇ m sampled from any 9 locations of the conductive layer have the following requirements ( It is particularly preferable to satisfy B1).
  • Requirement (B1) “When one sample cube is divided into 27 unit cubes each having a side of 3 ⁇ m, and the volume Vd of the domain included in each unit cube is obtained, Vd is 2.7 ⁇ m 3 to 10.8 ⁇ m. The number of unit cubes that are 3 must be at least 20. "
  • the developing member for electrophotography having a conductive path with extremely uniform and non-uniformity in which conductive domains with uniform electrical resistance are arranged in a conductive layer three-dimensionally and uniformly in a conductive layer
  • the following mechanism is estimated as a factor that makes it possible to move charges in a conductive path more efficiently even under a high-speed process.
  • ⁇ and ⁇ When the relationship between ⁇ and ⁇ is “ ⁇ / ⁇ is 0 or more and 0.4 or less”, the number and amount of portions (for example, conductive particles) made of a conductive agent contained in each domain vary. Disappear. As a result, a domain with uniform electrical resistance is obtained. In particular, when the relationship between ⁇ and ⁇ is “ ⁇ / ⁇ is 0 or more and 0.25 or less”, the domain becomes more uniform in electrical resistance, and thus the effect of the present invention tends to increase. Particularly preferred. In order to reduce ⁇ / ⁇ , it is preferable to increase the number and amount of the conductive particles contained in each domain, and it is also preferable to make the sizes of the domains uniform. Here, ⁇ is preferably 20% or more and 40% or less.
  • is less than 20%, the amount of the conductive particles is inevitably small, and the electrical connection of the conductive particles in the domain may become percolation unstable. is there.
  • is larger than 40%, the amount of conductive particles in the domain increases, so that it may be difficult to confine the conductive particles in the domain.
  • the effect of the present invention is enhanced when the amount of conductive particles in the domain is increased. More preferably, ⁇ is 23% or more, and more preferably 28% or more. .
  • the conductive domain is three-dimensionally uniform and The structure is densely arranged in the conductive layer.
  • the ratio of being present uniformly in the entire conductive layer tends to increase.
  • the ratio of the domains uniformly existing in the entire conductive layer is dramatically increased by reducing the domain size and increasing the number of domains.
  • Vd is 2.7 .mu.m 3 ⁇ 10.8 3 a is the number of unit cube 20 or more, more preferably 22 or more, 25 More preferably, it is the above.
  • the connection of the conductive path from the conductive support to the surface of the conductive layer cannot be accurately established only by controlling the domain arrangement in a certain two-dimensional cross section.
  • “the conductive path is connected” means that the electric charge efficiently moves between domains forming the conductive path with a desired applied voltage (hopping conduction, tunnel conduction, band conduction, etc.) It refers to the state that can be done.
  • the thickness of the conductive layer, and the electrical resistance of the domain or matrix the distance between adjacent wall surfaces of the domain is particularly preferably 2.0 ⁇ m or less in a three-dimensional evaluation.
  • the developing member according to this aspect can be formed, for example, through a method including the following steps (i) to (iv).
  • CMB domain-forming rubber mixture
  • MRC matrix-forming rubber mixture
  • the configurations (i) to (iii) can be controlled by, for example, selecting materials used in the above steps and adjusting manufacturing conditions. This will be described below.
  • the configuration (i) the volume resistivity of the matrix is determined by the composition of the MRC.
  • the first rubbers used in MRC are low conductivity, natural rubber, butadiene rubber, butyl rubber, acrylonitrile butadiene rubber, urethane rubber, silicone rubber, fluorine rubber, isoprene rubber, chloroprene rubber, styrene-butadiene rubber, ethylene-propylene. At least one rubber such as rubber and polynorbornene rubber can be used.
  • a filler on the premise that the volume resistivity of the matrix can be within the above range, a filler, a processing aid, a cross-linking agent, a cross-linking aid, a cross-linking accelerator, a cross-linking promotion aid are provided as necessary.
  • An agent, a crosslinking retarder, an anti-aging agent, a softener, a dispersant, and a colorant may be added.
  • the MRC preferably does not contain an electronic conductive agent such as carbon black. Further, the configuration (ii) can be adjusted by the amount of the electronic conductive agent in the CMB.
  • DBP oil absorption amount, 40 cm 3/100 g or more taking as an example the case of using a conductive carbon black is not more than 170cm 3/100 g, based on the total weight of the CMB, 40 wt% or more
  • the composition (ii) can be achieved by preparing CMB so as to contain 200% by mass or less of conductive carbon black.
  • the interfacial tension difference between CMB and MRC is considered to correlate with the SP value difference between the rubbers contained in each interfacial tension between CMB and MRC.
  • the difference in the absolute value of the solubility parameter is 0.4 (J / cm 3 ) 0.5 or more, 5.0 (J / cm 3 It is preferable to select a rubber that is 0.5 or less, in particular 0.4 (J / cm 3 ) 0.5 or more and 2.2 (J / cm 3 ) 0.5 or less. Within this range, a stable phase separation structure can be formed, and the domain diameter D of CMB can be reduced.
  • the thickness of the conductive layer is not particularly limited as long as the intended function and effect of the conductive member can be obtained.
  • the thickness of the conductive layer is preferably at least 100 ⁇ m (0.1 mm) or more, particularly 0.3 mm or more, and more preferably 1.0 mm or more. Moreover, it is preferable to set it as 4.5 mm or less.
  • the SP value can be accurately calculated by creating a calibration curve using a material whose SP value is known.
  • the catalog value of the material manufacturer can also be used for this known SP value.
  • NBR and SBR do not depend on the molecular weight, and the SP value is almost determined by the content ratio of acrylonitrile and styrene. Therefore, a material having a known SP value can be obtained by analyzing the content ratio of acrylonitrile or styrene of rubber constituting the matrix and domain using an analysis method such as pyrolysis gas chromatography (Py-GC) and solid-state NMR.
  • the SP value can be calculated from the calibration curve obtained from the above.
  • the isoprene rubber is composed of isomers such as 1,2-polyisoprene, 1,3-polyisoprene, 3,4-polyisoprene, and cis-1,4-polyisoprene and trans-1,4-polyisoprene.
  • the SP value is determined by the structure. Therefore, similarly to SBR and NBR, the isomer content ratio can be analyzed by Py-GC, solid NMR, etc., and the SP value can be calculated from a material having a known SP value.
  • the viscosity ratio is preferably 1.0 or more and 2.0 or less.
  • the viscosity ratio between CMB and MRC can be adjusted by selecting the Mooney viscosity of the raw rubber used for CMB and MRC and by blending the type and amount of filler. It is also possible to add a plasticizer such as paraffin oil to the extent that it does not interfere with the formation of the phase separation structure.
  • the viscosity ratio can be adjusted by adjusting the temperature at the time of kneading.
  • the viscosity of the rubber mixture for forming a domain and the rubber mixture for forming a matrix can be obtained by measuring Mooney viscosity ML (1 + 4) at the rubber temperature at the time of kneading based on JIS K6300-1: 2013.
  • C Shear rate during kneading of MRC and CMB, and energy amount during shearing As the shear rate during kneading of MRC and CMB is faster, and as the energy amount during shearing is larger, the inter-domain distance decreases. can do.
  • the shear rate can be increased by increasing the inner diameter of the stirring member such as the blade or screw of the kneading machine, reducing the gap from the end face of the stirring member to the inner wall of the kneading machine, or increasing the rotational speed. Further, increasing the energy during shearing can be achieved by increasing the number of revolutions of the stirring member or by increasing the viscosity of the first rubber in the CMB and the second rubber in the MRC.
  • D Volume fraction of CMB relative to MRC The volume fraction of CMB relative to MRC correlates with the collision coalescence probability of the domain forming rubber mixture relative to the matrix forming rubber mixture.
  • the volume fraction of the domain-forming rubber mixture with respect to the matrix-forming rubber mixture when the volume fraction of the domain-forming rubber mixture with respect to the matrix-forming rubber mixture is reduced, the collision coalescence probability between the domain-forming rubber mixture and the matrix-forming rubber mixture is lowered.
  • the inter-domain distance can be reduced by reducing the volume fraction of domains in the matrix within a range where necessary conductivity can be obtained.
  • the volume fraction with respect to MRC of CMB shall be 15% or more and 40% or less.
  • the shape of the domain is preferably close to a circle.
  • the ratio of the area of the domain to the area of a circle corresponding to the maximum ferret diameter of the domain is preferably 0.6 or more and 1 or less. This ratio has a maximum value of 1 and a state of 1 indicates that the domain is a perfect circle.
  • these ratios are smaller than 0.6, the shape of the domain has anisotropy, that is, the anisotropy of the electric field appears. As a result, an electric field concentration point is formed, and the concentration of charge transport occurs, so that a highly sustainable discharge is likely to occur. The closer these ratios are to 1, the more the electric field concentration is suppressed, and thus fog images are less likely to occur.
  • the maximum ferret diameter is a value when the outer circumference of the observed domain is sandwiched between two parallel lines and the length when the two parallel lines are connected by a perpendicular line is the longest.
  • the circle corresponding to the maximum ferret diameter is a circle having the maximum ferret diameter as a diameter.
  • a ratio between the actual domain area S1 and the area S2 of the circle corresponding to the maximum ferret diameter obtained from the maximum ferret diameter may be obtained.
  • slice samples were cut out one by one from each of the regions obtained by dividing the developing member equally, preferably equally into 20 sections, and after obtaining the above measured values, a total of 20 samples of S1,
  • the arithmetic average value of S2 may be the measured values of S1 and S2.
  • a slice sample is cut out from each of the regions divided into four in the cylindrical circumferential direction and five in the longitudinal direction, and after obtaining the above measured values, a total of 20 samples are obtained.
  • the arithmetic average value of S1 and S2 may be the measured values of S1 and S2.
  • the conductive layer has a length of the conductive layer when the length in the longitudinal direction of the conductive layer is L.
  • the depth from the outer surface of the elastic layer is 0.1T to 0.9T for each of the cross sections in the thickness direction of the conductive layer at the center in the direction and at three points L / 4 from both ends of the conductive layer toward the center.
  • Requirement (B2) The ratio of the cross-sectional area of the conductive particles included in the domain to the cross-sectional area of the domain is 20% or more.
  • Requirement (B3) When the perimeter of the domain is A and the envelope perimeter of the domain is B, A / B is 1.00 or more and 1.10 or less.
  • the requirement (B2) and the requirement (B3) can be said to be regulations relating to the shape of the domain.
  • the “domain shape” is defined as a cross-sectional shape of a domain that appears in a cross-section in the thickness direction of the conductive layer.
  • the length in the longitudinal direction of the conductive layer is L and the thickness of the conductive layer is T
  • the length in the longitudinal direction of the conductive layer and from both ends of the conductive layer toward the center is L.
  • a cross section in the thickness direction of the conductive layer as shown in FIG. For each of the obtained cross-sections, 15 ⁇ m square observation regions are placed at any three locations in the thickness region from the outer surface of the conductive layer to the depth of 0.1T to 0.9T in the direction of the support.
  • the domain shape is defined by the shape of each domain observed in each of the nine observation regions.
  • the shape of the domain is preferably a shape having no irregularities on its peripheral surface.
  • the present inventor has found that the amount of conductive particles contained in one domain has an influence on the outer shape of the domain. That is, it was found that the outer shape of the domain becomes closer to a sphere as the filling amount of the conductive particles of one domain increases. As the number of domains close to a sphere increases, the concentration point of electron transfer between domains can be reduced.
  • the ratio of the sum of the cross-sectional areas of the conductive particles observed in the cross section is 20% or more based on the area of the cross section of one domain.
  • the domain that is can take a shape closer to a sphere.
  • the ratio of the cross-sectional area of the conductive particles included in the domain to the cross-sectional area of the domain is preferably 20% or more.
  • the present inventors have found that it is preferable to satisfy the following formula (9) for a shape having no irregularities on the peripheral surface of the domain.
  • Equation (9) shows the ratio of the perimeter length A of the domain to the envelope perimeter length B of the domain.
  • the envelope perimeter is the length of the convex envelope 73 of the domain 71 observed in the observation region, as shown in FIG.
  • the convex envelope is a minimum convex set including all points in the domain 71.
  • the ratio of the perimeter of the domain to the envelope perimeter of the domain has a minimum value of 1, and a state of 1 indicates that the domain has a cross-sectional shape such as a perfect circle or an ellipse with no recess.
  • DBP dibutyl phthalate carbon black
  • JIS Japanese Industrial Standards
  • K 6217-4 the carbon black for rubber - basic characteristics -Part 4: Measured according to how oil absorption is determined (including compressed samples).
  • carbon black has a tufted higher order structure in which primary particles having an average particle diameter of 10 nm or more and 50 nm or less are aggregated.
  • a carbon black having a developed structure has a high reinforcing property against rubber, and the incorporation of carbon black into the rubber becomes poor, and the shear torque at the time of kneading becomes very high. Therefore, it is difficult to increase the filling amount in the domain.
  • conductive carbon black having DBP absorption in the above range has less developed structure, and therefore has less carbon black aggregation and good dispersibility in rubber. Therefore, the amount of filling into the domain can be increased, and as a result, the outer shape of the domain can be easily obtained closer to a sphere.
  • carbon black having a developed structure tends to aggregate together, and the aggregate tends to be a lump having a large uneven structure.
  • a slice is prepared by the same method as that used in the measurement of the volume resistivity of the matrix. However, as described below, it is necessary to create a section with a cross section perpendicular to the longitudinal direction of the conductive member, and to evaluate the shape of the domain in the fracture surface of the section. The reason is described below.
  • 8A and 8B are diagrams showing the shape of the developing member 81 as three axes, specifically, the three dimensions of the X, Y, and Z axes.
  • FIG. 8A shows an image diagram of cutting out the developing member at a cross section 82a parallel to the XZ plane 82 with respect to the developing member.
  • the XZ plane can be rotated 360 ° about the axis of the developing member.
  • a cross section 82a parallel to the XZ plane 82 shows a surface where charge supply occurs simultaneously at a certain timing. Will be.
  • the cross-section 83b at the center in the longitudinal direction of the conductive layer, and two locations of L / 4 from both ends of the conductive layer toward the center A total of three sections (83a and 83c) are selected. Further, regarding the observation position of the cross sections 83a to 83c, when the thickness of the conductive layer is T, any three thickness regions from the outer surface of each section to a depth of 0.1 T or more and 0.9 T or less are used. The measurement may be performed in a total of nine observation regions when 15 ⁇ m square observation regions are placed at various locations.
  • the fracture surface can be formed by means such as a freezing cleaving method, a cross polisher method, or a focused ion beam method (FIB).
  • the FIB method is preferable in consideration of the smoothness of the fracture surface and pretreatment for observation.
  • a pretreatment such as a dyeing treatment or a vapor deposition treatment that can suitably obtain the contrast between the conductive phase and the insulating phase may be performed.
  • the matrix domain structure can be observed with a scanning electron microscope (SEM) or a transmission electron microscope (TEM) with respect to a section subjected to formation of a fracture surface and pretreatment.
  • Measurement of the perimeter of the domain, the perimeter of the envelope, and the number of domains can be performed by quantifying the captured image as described above.
  • image processing such as ImageProPlus (manufactured by Media Cybernetics) on the fracture surface image obtained by observation with SEM
  • each 15 ⁇ m square analysis area Extraction and 8-bit gray scale are performed to obtain a 256-tone monochrome image.
  • the black and white of the image is inverted so that the domain in the fracture surface becomes white, and binarized to obtain a binarized image for analysis.
  • the ratio of the cross-sectional area of the electronic conductive agent in the domain can be measured by quantifying the binarized image.
  • the cross-sectional area S of the domain and the sum of the cross-sectional areas of the portions made of the conductive agent in each domain are calculated by the counting function in the image processing software ImageProPlus (Media Cybernetics). Then, the arithmetic average value ⁇ (%) of Sc / S may be calculated.
  • the length of the conductive layer in the longitudinal direction is L and the thickness of the conductive layer is T
  • the length in the longitudinal direction of the conductive layer and the distance from both ends of the conductive layer toward the center are L.
  • a cross section in the thickness direction of the conductive layer as shown in FIG. For each of the obtained cross-sections, the above measurement was performed at any three 15 ⁇ m square regions in the thickness region from the outer surface of the conductive layer to the depth of 0.1T to 0.9T in the direction of the support. It may be calculated from the arithmetic average of the measured values from a total of nine points.
  • Measurement Method of Domain Perimeter A and Envelope Perimeter B The measurement of the perimeter of the domain, the perimeter of the envelope, and the number of domains can be performed by quantifying the binary image. For the binarized image, using the count function of the image processing software ImageProPlus (Media Cybernetics), calculate the perimeter length A of each domain in the domain size group in the image, the envelope perimeter length B of the domain, What is necessary is just to calculate the arithmetic mean value of perimeter length ratio A / B of a domain.
  • the length of the conductive layer in the longitudinal direction is L and the thickness of the conductive layer is T
  • the length in the longitudinal direction of the conductive layer and the distance from both ends of the conductive layer toward the center are L.
  • a cross section in the thickness direction of the conductive layer as shown in FIG. For each of the obtained cross-sections, the above measurement was performed at any three 15 ⁇ m square regions in the thickness region from the outer surface of the conductive layer to the depth of 0.1T to 0.9T in the direction of the support. It may be calculated from the arithmetic average of the measured values from a total of nine points.
  • the domain according to this aspect is the average of the maximum Feret diameter (hereinafter also simply referred to as “domain diameter”) L of domains included in each of the domains satisfying the configuration (iv) and the configuration (v) listed above.
  • the thickness is preferably 0.1 ⁇ m or more and 5.0 ⁇ m or less.
  • the average value of the domain diameter L is preferably 2.0 ⁇ m or less, and more preferably 1.0 ⁇ m or less for the above reason.
  • MRC and CMB are kneaded, and MRC and CMB are phase separated to prepare a rubber mixture in which CMB domains are formed in the matrix of MRC. And a method of controlling the CMB domain diameter to be small.
  • the specific surface area of the CMB is increased and the interface with the matrix is increased. Therefore, a tension for reducing the tension acts on the interface of the CMB domain. As a result, the outer shape of the CMB domain is closer to a sphere.
  • the matrix domain structure is governed by where the kneading process is stopped in the process where the raw material rubber of the domain is split in the kneading process and the grain system gradually becomes smaller. Therefore, the uniformity of the distance between the domains can be controlled by the kneading time in the kneading process and the kneading speed that is an index of the strength of the kneading. As the size increases, the uniformity of the distance between domains can be improved.
  • Uniformity of domain size The more uniform the domain size, that is, the narrower the particle size distribution is.
  • the concentration of the electric charge in the matrix domain structure can be suppressed, and the easiness of the electric charge can be effectively increased over the entire surface of the developing member. it can.
  • the ratio ⁇ d / D of the standard deviation ⁇ d of the domain size and the average value D of the domain size is preferably 0 or more and 0.4 or less.
  • the uniformity of the domain size is also improved. improves.
  • the matrix domain structure is governed by where the kneading process is stopped in the process where the raw material rubber of the domain is split in the kneading process and the grain system gradually becomes smaller. Therefore, the uniformity of the domain size can be controlled by the kneading time in the kneading process and the kneading speed which is an index of the strength of the kneading. The longer the kneading time, the larger the kneading speed. The uniformity of domain size can be improved.
  • ⁇ Method for confirming the matrix domain structure Presence of the matrix domain structure in the conductive layer can be confirmed by preparing a thin piece from the conductive layer and observing the fractured surface formed in the thin piece in detail.
  • the thinning means include a sharp razor, a microtome, and an FIB.
  • pre-treatments such as dyeing treatment and vapor deposition treatment that can obtain a suitable contrast between the domain as the conductive phase and the matrix as the insulating phase are applied to the observation flakes. You may give it.
  • the black and white of the image is inverted so that the domain in the fracture surface becomes white, and binarization is performed to obtain an analysis image.
  • the presence / absence of the matrix domain structure may be determined based on the analysis image obtained by performing image processing so that the domain and the matrix are distinguished by binarization.
  • the analysis image includes a structure in which a plurality of domains exist in an isolated state in the matrix as shown in FIG. 6, the presence of the matrix domain structure in the conductive layer can be confirmed.
  • the domain isolation state may be a state in which each domain is arranged in a state where it is not connected to another domain, and the matrix communicates in the image, and the domain is divided by the matrix.
  • the total number of domains that do not have a contact with the border of the analysis area is the number of domains that exist in an isolated state as described above.
  • a state where the number is 80 percent or more is defined as a state having a sea-island structure.
  • the developing member may have an appropriate surface roughness as required.
  • the surface roughness is preferably in the range of 2.0 ⁇ m to 8.0 ⁇ m in terms of 10-point average roughness (Rz), and in the range of 2.0 ⁇ m to 4.5 ⁇ m. It is particularly preferred.
  • the surface roughness is preferably in the range of 0.0 ⁇ m to 6.0 ⁇ m in terms of ten-point average roughness (Rz), and preferably in the range of 0.0 ⁇ m to 1.5 ⁇ m. Particularly preferred.
  • examples of the method for forming the surface roughness of the developing member include polishing, mold transfer, and laser treatment.
  • examples of the method for forming the conductive layer include a method of molding a liquid rubber material and a method of extruding a kneaded rubber material.
  • examples of the molding method include mold molding, injection molding, extrusion molding, and centrifugal molding.
  • the developing member according to the present invention can be suitably used as a developing roller, a toner supply roller, a developing sleeve, and a developing blade in an electrophotographic apparatus as an electrophotographic image forming apparatus.
  • the developing member can be applied to any developing device such as a non-contact developing device and a contact developing device using magnetic one-component toner or non-magnetic one-component toner, and a developing device using two-component toner.
  • FIG. 10 is a schematic cross-sectional view showing an example of an electrophotographic apparatus in which the developing member according to the present invention is mounted as a developing roller of a contact-type developing device using a one-component toner.
  • the developing device 22 regulates the thickness of the toner container 20 containing the toner 15 as a one-component toner, the developing roller 16, the toner supply roller 19 that supplies toner to the developing roller 16, and the toner layer on the developing roller 16.
  • the developing roller 16 is located in an opening extending in the longitudinal direction in the toner container 20 and is placed in contact with the photoreceptor 18.
  • the photoconductor 18, the cleaning blade 26, the waste toner container 25, and the charging roller 24 may be provided in the main body of the electrophotographic apparatus.
  • the developing device 22 is prepared for each color toner of black (Bk), cyan (C), magenta (M), and yellow (Y), and enables color printing.
  • Bk black
  • C cyan
  • M magenta
  • Y yellow
  • the photoconductor 18 rotates in the direction of the arrow and is uniformly charged by a charging roller 24 for charging the photoconductor 18.
  • an electrostatic latent image is formed on the surface of the photoreceptor 18 by the laser beam 23 that is an exposure means.
  • the electrostatic latent image is visualized as a toner image (development) by applying the toner 15 from the developing roller 16 disposed in contact with the photoreceptor 18 by the developing device 22. Development is so-called reversal development in which a toner image is formed in the exposed portion.
  • the toner image formed on the photosensitive member 18 is transferred to an endless belt-like intermediate transfer member 32 by a transfer roller 29 as a transfer member.
  • a paper 34 as a recording medium is fed into the apparatus by a paper feed roller 35 and a secondary transfer roller 36, and, together with an intermediate transfer body 32 having a toner image, is placed at a nip portion between the secondary transfer roller 36 and the driven roller 33.
  • the toner image is transferred to the paper 34 by being conveyed.
  • the intermediate transfer member 32 is operated by a driven roller 33, a driving roller 39, and a tension roller 38.
  • the toner remaining on the intermediate transfer member 32 is cleaned by the cleaning device 37.
  • a voltage is applied from the bias power supply 30 to the developing roller 16, the developing blade 21, the transfer roller 29, and the secondary transfer roller 36.
  • the paper 34 to which the toner image has been transferred is subjected to fixing processing by the fixing device 27 and discharged outside the device, and the printing operation is completed.
  • the untransferred toner remaining on the photoconductor 18 without being transferred is scraped off by a cleaning blade 26 which is a cleaning member for cleaning the surface of the photoconductor and stored in a waste toner container 25.
  • the cleaned photoreceptor 18 repeats the above printing operation.
  • FIG. 9 is a schematic cross-sectional view of an example of a process cartridge according to an aspect of the present invention.
  • the developing member is mounted as a developing roller 16.
  • the process cartridge 17 is configured to be detachable from the main body of the electrophotographic apparatus.
  • a developing device 22 including a developing roller 16 and a developing blade 21, a photoconductor 18, a cleaning blade 26, a waste toner container 25, and a charging roller 24 are integrated.
  • the developing device 22 further includes a toner container 20, and the toner container 20 is filled with the toner 15.
  • the toner 15 in the toner container 20 is supplied to the surface of the developing roller 16 by the toner supply roller 19, and a layer of the toner 15 having a predetermined thickness is formed on the surface of the developing roller 16 by the developing blade 21.
  • Example 1 Production of unvulcanized domain rubber composition
  • Example 1-1 Preparation of unvulcanized domain composition
  • the materials shown in Table 1 were mixed in a pressure kneader to obtain an unvulcanized domain composition.
  • a 6-liter pressure kneader (product name: TD6-15MDX, manufactured by Toshin Co., Ltd.) was used as the mixer.
  • the mixing conditions were a filling rate of 70 vol%, a blade rotation speed of 30 rpm, and 16 minutes.
  • a core metal having an outer diameter of 6 mm was prepared by subjecting the surface of free-cutting steel to electroless nickel plating. This core metal was used as a support which is a conductive shaft core.
  • a die having an inner diameter of 16.0 mm is attached to the tip of a crosshead extruder having a conductive support supply mechanism and an unvulcanized rubber roller discharge mechanism, and the temperature of the extruder and the crosshead is set to 80 ° C.
  • the conveyance speed of the conductive support was adjusted to 60 mm / sec.
  • the unvulcanized rubber composition was supplied from the extruder, and the outer peripheral portion of the conductive support was coated with the unvulcanized rubber composition in the crosshead to obtain an unvulcanized rubber roller.
  • the unvulcanized rubber roller is put into a hot air vulcanization furnace at 170 ° C. and heated for 60 minutes to vulcanize the unvulcanized rubber composition, and a conductive resin layer is formed on the outer periphery of the conductive support. A formed roller was obtained. Thereafter, both ends of the conductive resin layer were excised, and the surface of the conductive resin layer was polished with a rotating grindstone. As a result, a crown-shaped developing roller A1 having a diameter of 12.0 mm and a center diameter of 12.2 mm at positions of 90 mm from the center to both ends was obtained.
  • the developing roller A1 (longitudinal length: 230 mm) is divided into 5 equal parts in the longitudinal direction and divided into 4 equal parts in the circumferential direction. The above measurements were made. When the matrix domain structure was confirmed, “Yes” was indicated, and when it was not possible, “No” was indicated as “Presence / absence of sea island structure” in Table 7-1. [3-2] Measurement of slope at 1 ⁇ 10 6 Hz to 1 ⁇ 10 7 Hz and measurement of impedance at 1 ⁇ 10 ⁇ 2 Hz to 1 ⁇ 10 0 Hz Impedance was measured as follows. First, as a pretreatment, a measurement electrode was prepared by performing vacuum platinum deposition on the developing member A1 while rotating.
  • FIG. 11 shows a schematic diagram of a developing roller on which measurement electrodes are formed.
  • 41 is a conductive support
  • 42 is a conductive layer having a matrix domain structure
  • 44 is a platinum deposition layer
  • 43 is an aluminum sheet.
  • FIG. 12 shows a cross-sectional view of the developing roller in which the measurement electrode is formed on the conductive member.
  • 121 is a conductive support
  • 122 is a conductive layer having a matrix domain structure
  • 123 is a platinum deposition layer
  • 124 is an aluminum sheet.
  • FIG. 12 it is important to sandwich a conductive layer having a matrix domain structure between a conductive support and a measurement electrode.
  • the aluminum sheet was connected to a measurement electrode on the side of an impedance measuring device (trade name: Solartron 1260 and Solartron 1296; manufactured by Solartron).
  • FIG. 13 shows a schematic diagram of this measurement system. Impedance measurement was performed by using a conductive support and an aluminum sheet as two electrodes for measurement.
  • Impedance is measured in an environment with a temperature of 23 ° C and relative humidity of 50%. Vibration voltage is 1 Vpp, DC is 10 V, frequency is 1 ⁇ 10 -2 Hz to 10 7 Hz. ) And obtained the absolute value of the impedance. Next, using a spreadsheet such as Excel (registered trademark), the absolute value of the impedance and the angular frequency (measurement frequency ⁇ 2 ⁇ ⁇ (circumference ratio)) are log-logged and the measurement result is 1 ⁇ 10. The slope from 6 Hz to 1 ⁇ 10 7 Hz was calculated.
  • the developing roller A1 (longitudinal length: 230 mm) is divided into five equal areas in the longitudinal direction, and measurement electrodes are formed at 5 points in total, arbitrarily from each area.
  • an ultrathin slice having a thickness of about 2 ⁇ m was cut from the conductive layer of the developing roller using a microtome (trade name: Leica EM FCS, manufactured by Leica Microsystems) at a cutting temperature of ⁇ 100 ° C.
  • a microtome trade name: Leica EM FCS, manufactured by Leica Microsystems
  • the ultrathin slice is placed on a metal plate, selected from the locations that are in direct contact with the metal plate, and the location corresponding to the matrix is the SPM cantilever.
  • a voltage of 50 V was applied to the cantilever, and the current value was measured.
  • the surface shape of the measurement slice was observed with the SPM, and the thickness of the measurement location was calculated from the obtained height profile.
  • the volume resistivity was calculated from the thickness and the recess area, and was used as the volume resistivity of the matrix.
  • the developing roller A1 (longitudinal length: 230 mm) is divided into 5 equal parts in the longitudinal direction and 4 equal parts in the circumferential direction. The above measurements were made. The average value was taken as the volume resistivity of the matrix. The obtained results are shown in Table 7-1 as “volume resistivity” of “matrix”.
  • the domain according to this aspect is in the cross section of the conductive thickness direction when the thickness of the conductive layer is T.
  • an observation region of 15 ⁇ m square is placed at an arbitrary position in the thickness region from the outer surface of the conductive layer to a depth of 0.1 T to 0.9 T, there are 20 to 300 domains in the observation region. It is more preferable.
  • ⁇ Perimeter A ⁇ Envelope circumference: B -Ratio of A and B: A / B Number of domains satisfying the requirement (B3) This is divided into 5 equal parts in the longitudinal direction of the developing member A1 and 4 parts in the circumferential direction, and the arithmetic average value of the measurement results of the above items for each of the 20 areas is the domain It was for evaluation.
  • A according to requirement 3 is the perimeter of the domain 71 observed in the observation region
  • “B” is the length of the convex envelope 73 (envelope perimeter) of the domain. is there.
  • the values of the domain perimeter A and the envelope perimeter B were also arithmetic average values by the above method.
  • FIB-SEM is a technique of processing a sample with an FIB (Focused Ion Beam) apparatus and observing an SEM (scanning electron microscope) of an exposed cross section.
  • FIB-SEM scanning electron microscope
  • a three-dimensional stereoscopic image was obtained using FIB-SEM (manufactured by FI Eye Co., Ltd.), and the above configuration was confirmed from the image. That is, the conductive layer sampling is performed from any nine locations.
  • L the length in the longitudinal direction
  • L (1/4) L, (2/4) from the end.
  • L (3/4) Samples are cut out one by one from each of the three locations in the vicinity of L every 120 degrees in the circumferential direction of the roller. Then, three-dimensional measurement using FIB-SEM is performed, and a cube-shaped image with sides of 9 ⁇ m is measured at intervals of 60 nm.
  • the cross section of the conductive layer in each of the (1/4) L, (2/4) L, and (3/4) L sections is 90 degrees in the circumferential direction of the roller from the position of the core bar to the center of the surface. Measure.
  • a pretreatment that suitably obtains the contrast between the domain and the matrix.
  • a dyeing process can be suitably used. Then, using the 3D visualization / analysis software “Avizo” (trade name, manufactured by EF Corporation), the obtained image was converted into 27 samples contained in one cube-shaped sample having a side of 9 ⁇ m. The volume of the domain in the unit cube whose side is 3 ⁇ m is calculated.
  • the measurement of the distance between adjacent wall surfaces of the domain can be similarly performed using 3D visualization / analysis software Avizo, and after obtaining the above measurement value, it can be calculated by the arithmetic average of the total 27 samples. .
  • the obtained results are shown as “domain volume fraction” in Table 7-1.
  • FIB-SEM Uniform Dispersibility of Domain
  • FIB-SEM is a technique of processing a sample with an FIB (Focused Ion Beam) apparatus and observing an SEM (scanning electron microscope) of an exposed cross section.
  • SEM scanning electron microscope
  • FIB-SEM manufactured by FI Eye Co., Ltd.
  • FIB-SEM manufactured by FI Eye Co., Ltd.
  • a pretreatment that suitably obtains the contrast between the domain and the matrix.
  • a dyeing process can be suitably used.
  • the volume of the domain contained in the unit cube-shaped sample is calculated using 3D visualization / analysis software (trade name: Avizo, manufactured by FEI Corporation).
  • the measurement of the distance between adjacent wall surfaces of the domain can be similarly performed using the above-mentioned 3D visualization / analysis software Avido, and after obtaining the above measurement value, it can be calculated by the arithmetic average of the sample. it can. It was verified by the above-mentioned method that the conductive domains were three-dimensionally and uniformly arranged in the conductive layer.
  • three-dimensional measurement using FIB-SEM is performed, and it is evaluated whether at least eight samples out of the cube-shaped sample (sample cube) with a side of 9 ⁇ m satisfy the following conditions: To do.
  • Requirement (B1) “When one cubic sample is divided into 27 unit cubes each having a side of 3 ⁇ m, and the volume Vd of the domain included in each unit cube is determined, Vd is 2.7 ⁇ m 3 to 10.8 ⁇ m. The number of unit cubes that are 3 must be at least 20. " As described above, when the number of unit cubes in the sample cube satisfying the requirement (B1) is increased, the effect of the present invention is inevitably enhanced. The obtained results are shown in Table 8-1 as “the number of cubes satisfying the requirement (B1)”.
  • Ratio of the cross-sectional area of the electronic conductive agent contained in the domain to the cross-sectional area of the domain The ratio can be calculated using the SEM image observed in the above “Measurement of domain shape”. Platinum was vapor-deposited on the slice obtained by the above method to obtain a vapor deposition slice. Next, the surface of the vapor-deposited section was photographed at 1000 to 100,000 times using a scanning electron microscope (SEM) (product name: S-4800, manufactured by Hitachi High-Technologies Corporation) to obtain a surface image. Next, the image is converted to 8-bit gray scale using an image analysis device (product name: LUZEX-AP, manufactured by Nireco) to obtain a 256-tone monochrome image.
  • SEM scanning electron microscope
  • the black and white of the image is inverted so that the domain in the fracture surface becomes white, and binarization is performed. Further, an observation region having a size that can accommodate at least one domain is extracted from the SEM image, and the cross-sectional area Sd of the domain and the cross-sectional area Sc of the electronic conductive agent (carbon black) included in the domain are calculated.
  • Example 2 to 34 Except that the conductive support, domain rubber, matrix rubber raw materials, vulcanizing agent, vulcanization aid, etc. were changed to those shown in Table 5-1 to Table 6-5, the same procedure as in Example 1 was carried out. Development rollers of 2 to Example 34 were manufactured and evaluated. The evaluation results are shown in Table 7-1, Table 7-2, Table 8-1 and Table 8-2.
  • Example 35 As in Example 1, a cored bar having an outer diameter of 6 mm was prepared by subjecting the surface of free-cutting steel to electroless nickel plating.
  • Example 35 the core metal coated with the adhesive was used as a conductive shaft core. Thereafter, the examples except that the raw materials, vulcanizing agents, vulcanizing aids, etc. of the conductive support, domain rubber and matrix rubber were changed to those shown in Table 5-3 and Tables 6-2 to 6-5. In the same manner as in Example 1, a developing roller of Example 35 was obtained.
  • Example 36 A round bar having an outer diameter of 8 mm was formed by injection molding using a conductive thermoplastic resin (trade name: Torayca TLP1060; manufactured by Toray Industries, Inc.). Next, the round bar was polished to prepare a conductive resin core bar having an outer diameter of 6 mm and having the same shape as that of the free-cutting steel used in Example 1. In Example 36, this conductive resin cored bar was used as a conductive shaft core. Thereafter, Example 1 except that the conductive support, domain rubber, matrix rubber raw material, vulcanizing agent, vulcanizing auxiliary, etc. were changed to those shown in Table 5-3 and Tables 6-2 to 6-5. In the same manner as described above, the developing roller of Example 36 was obtained.
  • a conductive thermoplastic resin trade name: Torayca TLP1060; manufactured by Toray Industries, Inc.
  • Example 37 The conductive resin core used in Example 36 was prepared. Next, using a roll coater, METALOC U-20 (trade name, manufactured by Toyo Chemical Laboratory Co., Ltd.) was applied as an adhesive over the entire circumference excluding 15 mm at both ends of the core metal. In Example 37, the conductive resin core metal coated with the adhesive was used as a conductive shaft core. Thereafter, Example 1 except that the conductive support, domain rubber, matrix rubber raw material, vulcanizing agent, vulcanizing auxiliary, etc. were changed to those shown in Table 5-3 and Tables 6-2 to 6-5. In the same manner as described above, the developing roller of Example 37 was obtained.
  • METALOC U-20 trade name, manufactured by Toyo Chemical Laboratory Co., Ltd.
  • Example 38 A round bar having an outer diameter of 8 mm was formed by injection molding using PPS resin (trade name: Torelina A503-X05; manufactured by Toray Industries, Inc.). Next, the round bar was polished to prepare a PPS resin core metal having an outer diameter of 6 mm and having the same shape as that of the free-cutting steel used in Example 1. Platinum vapor deposition was applied to the entire outer surface of the obtained PPS resin core bar to obtain a shaft core body. Next, an adhesive was applied to the shaft core in the same manner as in Example 37. Thereafter, Example 1 except that the conductive support, domain rubber, matrix rubber raw material, vulcanizing agent, vulcanizing auxiliary, etc. were changed to those shown in Table 5-3 and Tables 6-2 to 6-5. In the same manner as described above, a developing roller having the shape of Example 38 was obtained.
  • PPS resin trade name: Torelina A503-X05; manufactured by Toray Industries, Inc.
  • E character image an image in which the letter “E” of the 4-point alphabet is printed so that the coverage is 1% with respect to the area of the A4 size paper (hereinafter also referred to as “E character image”).
  • E character image an image in which the letter “E” of the 4-point alphabet is printed so that the coverage is 1% with respect to the area of the A4 size paper.
  • E character image was continuously output on a predetermined number of copy sheets.
  • a solid white image was output on a new copy sheet, and the printer was stopped while the solid white image was being output.
  • the toner adhering to the photosensitive member is removed with a tape (trade name: CT18, manufactured by Nichiban Co., Ltd.), and the reflectance is measured with a reflection densitometer (trade name: TC-6DS / A, manufactured by Tokyo Electric Decoration Co., Ltd.).
  • a tape trade name: CT18, manufactured by Nichiban Co., Ltd.
  • the amount of decrease in reflectance (%) with respect to the reflectance of the tape was measured, and this was used as the fog value. Based on these fog values, the following criteria were used for evaluation. Rank A: The fog value is less than 1.5%. Rank B: The fog value is 1.5% or more and less than 3.0%. Rank C: The fog value is 3.0% or more and less than 5.0%. Rank D: The fog value is 5.0% or more. [4-2] Toner charge amount In order to evaluate the charging property of the developing roller to the toner, the charge amount was measured.
  • the toner carried on the narrow portion of the portion of the developing roller sandwiched between the toner regulating blade and the photoreceptor contact position was sucked and collected by the metal cylindrical tube and the cylindrical filter. .
  • the amount of charge stored in the capacitor through the metal cylindrical tube and the mass of the sucked toner were measured.
  • the charge amount was measured using a measuring machine (trade name: 8252) manufactured by ADC. From these values, the charge amount per unit mass ( ⁇ C / g) was calculated.
  • the sign of the charge amount per unit mass is negative, and the larger the absolute value, the higher the charge imparting property of the developing roller.
  • the value obtained by the measurement was defined as the toner charge amount.
  • Comparative Example 1 The materials shown in Table 9 were mixed with a pressure kneader to obtain a master batch.
  • a 6-liter pressure kneader (product name: TD6-15MDX, manufactured by Toshin Co., Ltd.) was used as the mixer.
  • the mixing conditions were a filling rate of 70 vol%, a blade rotation speed of 30 rpm, and 16 minutes.
  • This material was used as a developing roller molding rubber composition, and thereafter, a developing roller of Comparative Example 1 was obtained in the same manner as in Example 1.
  • Comparative Example 2 A developing roller of Comparative Example 2 was obtained in the same manner as Comparative Example 1, except that the rubber composition for molding the developing roller was changed to that shown in Table 10.
  • the materials shown in Table 12 were mixed with a pressure kneader to obtain an unvulcanized matrix composition.
  • a 6-liter pressure kneader (product name: TD6-15MDX, manufactured by Toshin Co., Ltd.) was used as the mixer.
  • the mixing conditions were a filling rate of 70 vol%, a blade rotation speed of 30 rpm, and 16 minutes.
  • each material in the amount shown in Table 14 was mixed with an open roll to prepare a rubber composition for forming a conductive member.
  • an open roll having a roll diameter of 12 inches (0.30 m) was used as the mixer.
  • the mixing conditions were a front roll rotation speed of 10 rpm and a rear roll rotation speed of 8 rpm, and after turning left and right a total of 20 times with a roll gap of 2 mm, thinning was performed 10 times with a roll gap of 0.5 mm.
  • Comparative Example 3 This material was used as a developing roller molding rubber composition, and thereafter, a developing roller of Comparative Example 3 was obtained in the same manner as in Example 1.
  • Comparative Examples 4 to 8 and Comparative Example 12 Comparative Example 4 to Comparative Example 8 as in Comparative Example 3 except that the conductive support, domain rubber, matrix rubber raw material, vulcanizing agent, and vulcanization aid were changed to those shown in Tables 16 and 17.
  • a developing roller of Comparative Example 12 was obtained.
  • Comparative Example 9 An elastic layer made of hydrin rubber was formed in the same manner as in Comparative Example 1 except that the developing roller molding rubber composition was changed to those shown in Tables 16 and 17.
  • the dipping coating immersion time was 9 seconds, the pulling speed was 20 mm / sec for the initial speed, 2 mm / sec for the final speed, and the speed was changed linearly with respect to the time.
  • the obtained coated material was air-dried at room temperature for 30 minutes, then dried in a hot air circulating dryer set at 90 ° C. for 1 hour, and further dried in a hot air circulating dryer set at 160 ° C. for 1 hour. 9 developing rollers were obtained.
  • Comparative Example 10 A developing roller of Comparative Example 10 was obtained in the same manner as Comparative Example 1 except that the rubber composition for molding the developing roller was changed to those shown in Tables 16 and 17.
  • Comparative Example 11 The raw materials, vulcanizing agents, and vulcanization aids for the conductive support / matrix rubber were changed to those shown in Tables 16 and 17, and the domain rubber material was vulcanized by heating alone and then changed to freeze-pulverized rubber particles.
  • a developing roller of Comparative Example 11 was obtained in the same manner as in Example 1 except that.
  • the conductive rubber particles having a large size and anisotropic formed by freeze pulverization are dispersed, the conductive path in the conductive member is formed unevenly. It is synonymous with a state where the thickness is large. As a result, the slope of impedance at high frequency is -1.
  • Tables 18 and 19 show the results of evaluating the developing rollers obtained in Comparative Examples 1 to 12 in the same manner as in Example 1.
  • Example 39 The unvulcanized rubber composition obtained in Example 2 was used. Here, the unvulcanized rubber composition is treated at 160 ° C.
  • a rubber sheet 1 of 7 mm was obtained.
  • the rubber sheet 1 is cut into a width of 215 mm and a length of 12 mm, and an adhesive is applied to a sheet metal (same shape as that used for a developing blade of an electrophotographic process cartridge described later) that has been processed in advance to be attached to a predetermined cartridge.
  • a developing blade of Example 39 At this time, the developing blade was bonded so that the portion of 12 mm in length overlapping with the sheet metal was 4.5 mm, and the remaining 7.5 mm was protruded from the sheet metal.
  • the adhesive used was a conductive hot melt type.
  • Impedance Slope Impedance measurement was performed as follows. First, as a pretreatment, a measurement electrode was prepared by applying a silver paste to a developing blade. At this time, using a masking tape, a rectangular electrode having a length of 213 mm was formed at a portion of the tip from 1 mm to 6 mm on the surface where the sheet metal of the developing blade was not bonded. Next, a conductive wire was attached to the electrode using a silver paste, and the aluminum sheet was connected to a measurement electrode of an impedance measuring device (trade names: Solartron 1260 and Solartron 1296; manufactured by Solartron).
  • an impedance measuring device trade names: Solartron 1260 and Solartron 1296; manufactured by Solartron.
  • the impedance is measured at an oscillation voltage of 1 Vpp, a direct current of 10 V, and a frequency of 1.0 ⁇ 10 ⁇ 2 Hz to 1.0 ⁇ 10 7 Hz in an environment of a temperature of 23 ° C. and a relative humidity of 50% (the frequency changes by an order of magnitude. In this case, measurement was performed at 5 points) to obtain an absolute value of impedance.
  • the absolute value of the impedance and the angular frequency (measurement frequency ⁇ 2 ⁇ ⁇ (circumferential ratio)) are log-logged and the measurement result is 1.0 ⁇ 10 6 Hz.
  • the slope at ⁇ 1.0 ⁇ 10 7 Hz was calculated.
  • Example 40 to 44 Development of Examples 40 to 44 in the same manner as in Example 39 except that the conductive support, domain rubber, matrix rubber raw material, vulcanizing agent, and vulcanization aid were changed to those shown in Tables 20 and 21. A blade was manufactured. Note that “Zeospan” in Table 20 is a polyether synthetic rubber manufactured by Nippon Zeon.
  • Comparative Examples 13 to 17 were the same as Example 39 except that the conductive support, domain rubber, matrix rubber raw materials, vulcanizing agent, and vulcanization aid were changed to those shown in Tables 22 and 23. The developing blade was manufactured.
  • the laser printer was modified so that the number of output sheets per unit time was 75 sheets / minute with A4 size paper, which was larger than the original output number. At that time, the output speed of the recording medium was 370 mm / second, and the image resolution was 1,200 dpi. Further, it was left for 48 hours in an environment of a temperature of 23 ° C. and a relative humidity of 50%.
  • the voltage application electrode to the developing blade was modified to allow voltage application by an external power source, and the metal portion of the developing sleeve and the sheet metal of the developing blade were electrically connected.
  • a solid white image with a printing rate of 0% is output to the recording paper in the same environment, and the color laser printer is turned on during printing. Drop it.
  • the charge amount Q / M ( ⁇ C / g) of the toner on the developing sleeve before passing through the nip between the photosensitive member and the developing sleeve is measured.
  • the specific measurement of the toner charge amount is the same as the evaluation of the developing roller.
  • the above operation is repeated three times for one developing sleeve, and the charge amount of the toner is measured three times, and the arithmetic average value thereof is obtained to obtain the toner charge amount when the developing blade of the present invention is used. Further, when the printer is stopped while outputting a solid white image, the developer adhering to the photoconductor before being transferred is peeled off with a tape, and a reflection densitometer (trade name: TC-6DS / A; Tokyo, Japan). The reflectance R 1 of the tape is measured by Denki Co., Ltd., and the amount of decrease in reflectance “R 0 -R 1 ” (%) relative to the reflectance R 0 standard of the unused tape is calculated.
  • Rank A The fog value is less than 1.5%.
  • Rank B The fog value is 1.5% or more and less than 3.0%.
  • Rank C The fog value is 3.0% or more and less than 5.0%.
  • Rank D The fog value is 5.0% or more.
  • Toner Charge Amount In order to evaluate the charge imparting property of the developing blade to the toner, the charge amount was measured. During the above fog image evaluation, the toner carried on the narrow portion of the portion of the developing sleeve sandwiched between the developing blade and the photoreceptor contact position was sucked and collected by the metal cylindrical tube and the cylindrical filter.
  • the charge amount distribution was measured using an E-spar Analyzer Model EST-III (manufactured by Hosokawa Micron Corporation). Otherwise, the charge amount distribution was measured in the same manner as the toner charge amount measurement. The number of measured particles was about 3000. The standard deviation was calculated from the obtained charge amount distribution, and the obtained value was used as the initial charge amount distribution of the toner. The evaluation results are shown in Tables 24 to 27.
  • the developing blades according to Examples 39 to 44 have the configuration of the present invention in the conductive layer, a high-quality image with a sharp charge distribution and a very small fog value can be obtained. It was. On the other hand, in the developing blades according to Comparative Examples 13 to 17, the toner charge amount distribution was large and the image quality was not good.

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Abstract

The present invention provides a developing member which can maintain high picture quality and high durability in a high-speed process. As a developing member for electrophotography having a conductive support body and a conducting layer provided on the support body, a developing member is used in which: the conducting layer has a matrix comprising a first rubber and a plurality of domains distributed within the matrix; the domains comprise a second rubber and an electron conducting material; under a specified environment, impedance measured by applying AC voltage having an amplitude of 1V to the conducting layer while varying the frequency thereof between 1.0×10-2 Hz to 1.0×107 Hz, inclusive, has a slope on a high-frequency side of -0.8 to -0.3, inclusive, when plotted on a double logarithmic plot having frequency as a horizontal axis and impedance as a vertical axis; and the impedance on a low-frequency side is 1.0×104 Ω to 1.0×1011 Ω, inclusive.

Description

現像部材、プロセスカートリッジおよび電子写真装置Developing member, process cartridge, and electrophotographic apparatus
 本発明は、電子写真装置に用いられる現像部材、該現像部材を有するプロセスカートリッジおよび電子写真装置に関する。 The present invention relates to a developing member used in an electrophotographic apparatus, a process cartridge having the developing member, and an electrophotographic apparatus.
 電子写真装置において、現像ローラ、トナー供給ローラ、および現像ブレードの如き現像部材として、例えば、1×10~1×1012Ωの如き電気抵抗値(以降、「抵抗値」という)を有する導電層を備えた現像部材が用いられている。従来、導電層に導電性を付与し、安定な導電機構の形成のために、カーボンブラックのような電子導電剤や、第4級アンモニウム塩等のイオン導電剤が使用されてきた。
 現像部材には電子写真感光体(以降、「感光体」という)へのトナー搬送、トナーへの電荷付与、表面汚染のしにくさなど、様々な機能が求められ、これらを達成するため種々の対策手段が開示されている。
 特許文献1では、表面に連続相と非連続相を有するロール状の現像剤担持体を用いることによりトナー離型性や摩耗性を向上させる方法が開示されている。
 また、特許文献2では、導電性部材の表面層が非導電性の海部と電子導電剤を含む島部からなる海島構造を有することで、放電ムラを低減する方法が開示されている。
In an electrophotographic apparatus, as a developing member such as a developing roller, a toner supply roller, and a developing blade, a conductive material having an electrical resistance value (hereinafter referred to as “resistance value”) such as 1 × 10 5 to 1 × 10 12 Ω, for example. A developing member having a layer is used. Conventionally, an electron conductive agent such as carbon black or an ionic conductive agent such as a quaternary ammonium salt has been used for imparting conductivity to a conductive layer and forming a stable conductive mechanism.
The developing member is required to have various functions such as toner conveyance to an electrophotographic photoreceptor (hereinafter referred to as “photoreceptor”), charge application to the toner, difficulty in surface contamination, and the like. Countermeasures are disclosed.
Patent Document 1 discloses a method for improving toner releasability and wear by using a roll-shaped developer carrier having a continuous phase and a discontinuous phase on the surface.
Patent Document 2 discloses a method of reducing discharge unevenness by having a sea-island structure in which a surface layer of a conductive member includes a non-conductive sea part and an island part containing an electronic conductive agent.
特開平5-72889号公報JP-A-5-72889 特開2011-22420号公報JP 2011-22420 A
 近年、電子写真装置には、過酷な環境での高速プロセスにおいても高画質、高耐久性を維持できることが求められている。
 例えばカーボンブラックのような電子導電剤を導電層中に分散させると、導電性支持体から導電性部材表面まで電子導電剤が連結した導電パスの中を、電荷が移動することで導電性が発現する。したがって、この導電パスが、通電で消費する電荷の輸送を担うため、次の通電のための電荷の供給までに一定の時間を要する。
 すなわち、高速プロセスにおいては、トナーに与える電荷の供給がプロセス速度に追随できない場合に、トナーに与える電荷量のばらつきが生じる。これにより均一な現像を実現することが難しくなり、例えば、帯電量の乏しいトナーが画像に現れるカブリ画像が発生する場合があった。
 また、導電層中にイオン導電剤を分散させて導電性を発現する導電性部材は、第4級アンモニウムのようなアニオンとカチオンが移動することによって導電性が発現する。したがって、高速プロセスにおいては、アニオンやカチオンの移動速度が遅い場合、プロセス速度に追随できず、上記と同様に、次の現像のためのトナーへの電荷供給が不足し、カブリ画像が発生することがあった。
 導電パス内の電荷の動きと、トナーへの電荷付与のプロセスは次のように推測される。
 まず、電源に接続された導電性支持体に電圧が印可され、電荷が供給される。この電荷は、導電性部材の導電層を通って、現像部材の表面まで輸送(供給)される。
 この状態で現像部材の表面がトナーと接触すると、現像部材の表面の電荷が、トナーに移動する、すなわち電荷がトナーに供給される。
 トナーに移動した分だけ、現像部材の表面の電荷が減少するが、現像部材の導電性支持体が電源に接続されている限り、導電性支持体を通じて、新たな電荷が現像部材の表面に供給される。
 このように、新たな電荷が連続的に現像部材に供給されることにより、トナーへの電荷供給を連続的に行うことができる。
In recent years, an electrophotographic apparatus is required to maintain high image quality and high durability even in a high-speed process in a harsh environment.
For example, when an electronic conductive agent such as carbon black is dispersed in the conductive layer, the conductivity is manifested by the movement of charges through the conductive path where the electronic conductive agent is connected from the conductive support to the surface of the conductive member. To do. Accordingly, since this conductive path is responsible for transporting the electric charge consumed by energization, it takes a certain time until the electric charge is supplied for the next energization.
That is, in the high-speed process, when the supply of the charge applied to the toner cannot follow the process speed, the amount of charge applied to the toner varies. This makes it difficult to achieve uniform development. For example, a fogged image in which toner having a low charge amount appears in the image may occur.
In addition, a conductive member that exhibits conductivity by dispersing an ionic conductive agent in the conductive layer exhibits conductivity when anions and cations such as quaternary ammonium move. Therefore, in a high-speed process, when the movement speed of anions and cations is slow, the process speed cannot be followed, and as described above, the charge supply to the toner for the next development is insufficient and a fog image is generated. was there.
The process of charge movement in the conductive path and the process of applying charge to the toner can be estimated as follows.
First, a voltage is applied to a conductive support connected to a power source, and electric charges are supplied. This electric charge is transported (supplied) through the conductive layer of the conductive member to the surface of the developing member.
When the surface of the developing member comes into contact with the toner in this state, the charge on the surface of the developing member moves to the toner, that is, the charge is supplied to the toner.
The charge on the surface of the developing member decreases by the amount transferred to the toner, but as long as the conductive support of the developing member is connected to the power source, new charge is supplied to the surface of the developing member through the conductive support. Is done.
In this way, new charges are continuously supplied to the developing member, so that the charge can be continuously supplied to the toner.
 一方、トナー担持体と現像ブレードを用いる現像プロセスにおいて、トナー粒子はトナー担持体表面に、2個~3個分程度の厚みのトナー層を形成し、感光体へと現像される。トナー担持体表面において、トナーは転動しながら、トナー担持体と現像ブレードの間を通過する非常に短い時間内に、トナー担持体から電荷の供給を受け、帯電付与される。
 したがって、現像部材の電荷の供給が停滞し、現像部材の導電層の電荷移動速度が遅いと、現像部材の表面への新たな電荷の供給量が制限されてしまう。単位時間あたりに多くのトナーに電荷を供給する必要がある高速プロセスにおいては、現像部材の表面への新たな電荷の供給量が制限されると、トナーへの電荷供給不足が発生する。その結果、現像部材表面との接触および転動時に受けた電荷量にばらつきが生じ、トナーの帯電量分布が大きくなる。さらに、現像部(感光体と現像部材とが対向する位置)において現像されにくいトナーができてしまい、いわゆるカブリが表れやすくなる。
 本発明者らは、現像部材の導電層の電荷移動速度を高めるために、導電層に導電剤を多量に配合し、導電層の低抵抗化を図った。
 しかし、イオン導電剤、電子導電剤のどちらを用いた場合であっても、高速プロセスの現像部において、十分に帯電されていないトナーの割合を低減する効果は小さく、期待するほどのカブリ低減効果は得られなかった。
 上記のように、高速プロセスにおいても高品位な画像を形成しうる現像部材を提供することは容易ではない。本発明者らの検討によれば、特許文献1に係る導電性ロールや特許文献2に係る導電性ローラは、高速プロセスでの画像評価において、電荷供給量の不足と思われる、カブリ画像を発生する場合があった。
On the other hand, in a development process using a toner carrier and a developing blade, toner particles form a toner layer having a thickness of about 2 to 3 on the surface of the toner carrier and are developed onto a photoreceptor. On the surface of the toner carrying member, the toner is supplied with electric charge from the toner carrying member within a very short time passing between the toner carrying member and the developing blade while being rolled.
Therefore, if the supply of charge to the developing member stagnate and the charge transfer speed of the conductive layer of the developing member is slow, the amount of new charge supplied to the surface of the developing member is limited. In a high-speed process that needs to supply a large amount of toner per unit time, if the amount of new charge supplied to the surface of the developing member is limited, insufficient supply of charge to the toner occurs. As a result, the amount of charge received at the time of contact and rolling with the surface of the developing member varies, and the toner charge amount distribution increases. Furthermore, toner that is difficult to be developed is formed at the developing portion (position where the photosensitive member and the developing member face each other), and so-called fog is likely to appear.
In order to increase the charge transfer speed of the conductive layer of the developing member, the present inventors have added a large amount of a conductive agent to the conductive layer to reduce the resistance of the conductive layer.
However, regardless of whether an ionic conductive agent or an electronic conductive agent is used, the effect of reducing the proportion of the toner that is not sufficiently charged is small in the developing portion of the high-speed process, and the fog reduction effect as expected. Was not obtained.
As described above, it is not easy to provide a developing member that can form a high-quality image even in a high-speed process. According to the study by the present inventors, the conductive roll according to Patent Document 1 and the conductive roller according to Patent Document 2 generate fog images that are considered to be insufficient in the amount of charge supply in image evaluation in a high-speed process. There was a case.
 本発明は、高速プロセスにおいても高画質、高耐久性を維持できる電子写真用現像部材の提供に向けたものである。また、本発明は、高品位な電子写真画像を安定して出力できる電子写真装置およびそれに用いられるプロセスカートリッジの提供に向けたものである。 The present invention is directed to providing an electrophotographic developing member capable of maintaining high image quality and high durability even in a high-speed process. The present invention is also directed to providing an electrophotographic apparatus capable of stably outputting high-quality electrophotographic images and a process cartridge used therefor.
 本発明の一態様によれば、導電性の外表面を有する支持体と、該支持体の外表面上に設けられた導電層を有する電子写真用の現像部材であって、該導電層は、第一のゴムを含むマトリックスと、該マトリックス中に分散された複数個のドメインとを有し、該ドメインは、第二のゴムおよび電子導電剤を含み、該現像部材の外表面に金属膜を設け、温度23℃、相対湿度50%の環境下で、該支持体の外表面と該金属膜との間に振幅が1Vの交流電圧を、周波数1.0×10-2Hz~1.0×10Hzの間で変化させながら印加することによってインピーダンスを測定し、周波数を横軸、インピーダンスを縦軸に両対数プロットしたときの、周波数1.0×10Hz~1.0×10Hzにおける傾きが、-0.8以上、-0.3以下であり、かつ、周波数が1.0×10-2Hz~1.0×10Hzにおけるインピーダンスが、1.0×10Ω~1×1011Ωである現像部材が提供される。
 また、本発明の他の態様によれば、電子写真装置の本体に着脱可能に構成されているプロセスカートリッジであって、上記の現像部材を具備するプロセスカートリッジが提供される。
 さらに、本発明の他の態様によれば、上記のプロセスカートリッジを具備する電子写真装置が提供される。
According to one aspect of the present invention, there is provided a developing member for electrophotography having a support having a conductive outer surface and a conductive layer provided on the outer surface of the support, the conductive layer comprising: A matrix including a first rubber; and a plurality of domains dispersed in the matrix, the domain including a second rubber and an electronic conductive agent, and a metal film on the outer surface of the developing member. provided, the temperature 23 ° C., under a relative humidity of 50%, an AC voltage of amplitude 1V, frequency 1.0 × 10 -2 Hz ~ between the outer surface and the metal film of the support 1.0 Impedance is measured by applying the voltage while changing between × 10 7 Hz, and the frequency is 1.0 × 10 6 Hz to 1.0 × 10 when the logarithm plots the frequency on the horizontal axis and the impedance on the vertical axis. The slope at 7 Hz is -0.8 or more and -0.3 or less And a developing member having an impedance at a frequency of 1.0 × 10 −2 Hz to 1.0 × 10 0 Hz is 1.0 × 10 4 Ω to 1 × 10 11 Ω.
According to another aspect of the present invention, there is provided a process cartridge configured to be detachable from a main body of an electrophotographic apparatus, the process cartridge including the developing member.
Furthermore, according to another aspect of the present invention, there is provided an electrophotographic apparatus comprising the above process cartridge.
 本発明の一態様によれば、高速プロセスにおいても高画質、高耐久性を維持できる電子写真用の現像部材が得られる。また、本発明の他の態様によれば、高品位な電子写真画像を安定して出力できる電子写真装置およびそれに用いられるプロセスカートリッジが得られる。 According to one aspect of the present invention, an electrophotographic developing member capable of maintaining high image quality and high durability even in a high-speed process is obtained. In addition, according to another aspect of the present invention, an electrophotographic apparatus capable of stably outputting a high-quality electrophotographic image and a process cartridge used therefor are obtained.
本発明の一実施形態に係る電子写真用現像ローラの概略断面図である。1 is a schematic cross-sectional view of an electrophotographic developing roller according to an embodiment of the present invention. 本発明の一実施形態に係る電子写真用現像ブレードの概略断面図である。1 is a schematic cross-sectional view of an electrophotographic developing blade according to an embodiment of the present invention. インピーダンス特性と周波数の関係を示すグラフの説明図である。It is explanatory drawing of the graph which shows the relationship between an impedance characteristic and a frequency. インピーダンスの挙動の説明図である。It is explanatory drawing of the behavior of an impedance. 現像ローラの長手方向に対して垂直な断面図である。It is sectional drawing perpendicular | vertical with respect to the longitudinal direction of a developing roller. 導電層中の海島構造の模式図である。It is a schematic diagram of the sea-island structure in a conductive layer. ドメインの包絡周囲長の測定方法の説明図である。It is explanatory drawing of the measuring method of the envelope perimeter of a domain. 現像部材を切り出す断面の切り出し方向の説明図である。It is explanatory drawing of the cutout direction of the cross section which cuts out a developing member. 現像部材を切り出す断面の切り出し方向の説明図である。It is explanatory drawing of the cutout direction of the cross section which cuts out a developing member. プロセスカートリッジの概要図である。It is a schematic diagram of a process cartridge. 電子写真装置の概要図である。It is a schematic diagram of an electrophotographic apparatus. 測定電極が形成された現像ローラの概要図である。It is a schematic diagram of the developing roller on which a measurement electrode is formed. 導電性部材に測定電極が形成された現像ローラの断面図である。It is sectional drawing of the developing roller in which the measurement electrode was formed in the electroconductive member. 導電層のインピーダンス測定系の概要図である。It is a schematic diagram of the impedance measurement system of a conductive layer.
 本発明者らは、前記目的を達成すべく鋭意検討を重ねた。トナーへの電荷付与に用いる現像部材の場合、トナーへの電荷付与に至る電荷は、電圧が印可される導電性支持体から、現像部材表面まで輸送され、現像部材表面の電位を形成する。この電荷を輸送する導電機構が、従来は、カーボンブラックのような電子導電剤の導電パスや、イオン導電剤の導電パスである。
 電圧の印可により、現像部材表面まで導電パスを経由して電荷が輸送され、トナーと現像部材との間に、電界が発生する。さらに現像部材表面とトナーの接触面において、電界により現像部材表面から電荷がトナーに移動する。トナーは通常2個~3個分の厚みを有するトナー層として現像部材表面に担持され、転動しながら現像部材との接触時に電荷の供給を受ける。
 また、トナーと現像部材との接触領域はある一定の面積を有する。この面積内でトナーへの電荷付与は複数回発生している。例えば、現像装置が現像ローラと現像ブレードを有する場合では、トナーが、現像ローラの回転、およびトナーの転動によって、現像ブレードとの接触領域を通過する間に、トナーへの電荷付与は複数回発生している。
 電荷付与が一度発生すると、現像部材表面から供給される電荷付与は一定時間持続し、現像部材表面まで輸送された電荷が消費される。電荷付与が終了すると、再び現像部材内部の導電パスから現像部材表面まで、消費された電荷が供給され、次の電荷付与が発生する。したがって最終的なトナーの有する電荷量は、この複数回の付与電荷量の積算と考えられる。
 上記に述べたように、トナーの環境や現像の履歴は、現像部材表面との接触部における電界に影響を与え、付与電荷量も左右されるため、通常の場合、トナーの電荷量は分布を有する。
 特に、高速プロセスの場合、トナーへの最初の電荷付与が生じたあとに、次の電荷付与のための電荷量の供給が追随できなくなる場合がある。特に、感光体と現像部材によって形成される現像ニップ領域に侵入してすぐの1回目の電荷付与は十分な量の電荷量を有したものになるが、その後の電荷付与のための電荷供給が追随できない場合がある。
The inventors of the present invention have intensively studied to achieve the above object. In the case of a developing member used for imparting charge to toner, the charge that leads to imparting charge to toner is transported from a conductive support to which a voltage is applied to the surface of the developing member to form a potential on the surface of the developing member. Conventionally, the conductive mechanism for transporting the charge is a conductive path of an electronic conductive agent such as carbon black or a conductive path of an ionic conductive agent.
By applying the voltage, electric charges are transported to the surface of the developing member via the conductive path, and an electric field is generated between the toner and the developing member. Further, electric charges move from the surface of the developing member to the toner due to the electric field at the contact surface between the surface of the developing member and the toner. The toner is usually carried on the surface of the developing member as a toner layer having a thickness of two to three, and is supplied with electric charge when it contacts with the developing member while rolling.
The contact area between the toner and the developing member has a certain area. Within this area, the toner is charged several times. For example, when the developing device has a developing roller and a developing blade, the toner is charged several times while passing through the contact area with the developing blade by rotation of the developing roller and rolling of the toner. It has occurred.
Once charge generation occurs, the charge supply supplied from the surface of the developing member lasts for a certain time, and the charge transported to the surface of the developing member is consumed. When the charge application is completed, the consumed charge is supplied again from the conductive path inside the developing member to the surface of the developing member, and the next charge application occurs. Therefore, the final charge amount of the toner is considered to be an accumulation of the applied charge amount for a plurality of times.
As described above, the toner environment and the development history affect the electric field at the contact portion with the surface of the developing member, and the amount of applied charge is also affected. Have.
In particular, in the case of a high-speed process, after the first charge is applied to the toner, it may be impossible to follow the supply of the charge amount for the next charge application. In particular, the first charge application immediately after entering the development nip region formed by the photosensitive member and the development member has a sufficient amount of charge, but the subsequent charge supply for charge application is not possible. It may not be possible to follow.
 そこで、本発明者らは、十分な電荷を短時間で蓄積でき、且つ、当該電荷を速やかに供給し得る現像部材を得るべく検討を重ねた。その結果、以下の構成の現像部材は、上記の要求に良く応え得ることを見出した。
 現像部材は、導電性の外表面を有する支持体と、該支持体の外表面上に設けられた導電層を有し、該導電層が、第一のゴムを含むマトリックスと、該マトリックス中に分散された複数個のドメインとを有し、該ドメインは、第二のゴムおよび電子導電剤を含む。
 該現像部材は、その外表面に金属膜を設け、温度23℃、相対湿度50%の環境下で、該支持体の外表面と該金属膜との間に振幅が1Vの交流電圧を、周波数1.0×10-2Hz~1.0×10Hzの間で変化させながら印加することによってインピーダンスを測定し、周波数を横軸、インピーダンスを縦軸に両対数プロットしたときに以下の第一の要件および第二の両方の要件を満たす。
Therefore, the present inventors have repeatedly studied to obtain a developing member capable of accumulating sufficient charges in a short time and capable of supplying the charges quickly. As a result, it has been found that a developing member having the following configuration can meet the above requirements well.
The developing member includes a support having a conductive outer surface, a conductive layer provided on the outer surface of the support, the conductive layer including a first rubber, and a matrix in the matrix. A plurality of dispersed domains, the domains including a second rubber and an electronic conductive agent.
The developing member is provided with a metal film on its outer surface, and an AC voltage having an amplitude of 1 V is applied between the outer surface of the support and the metal film in an environment of a temperature of 23 ° C. and a relative humidity of 50%. Impedance was measured by applying the voltage while changing between 1.0 × 10 −2 Hz and 1.0 × 10 7 Hz, and the following logarithmic plots were made with the frequency plotted on the horizontal axis and the impedance plotted on the vertical axis. Satisfy both the first and second requirements.
<第一の要件>
 周波数1.0×10Hz~1.0×10Hzにおける傾きが、-0.8以上、-0.3以下である。
<第二の要件>
 周波数が1.0×10-2Hz~1.0×10Hzにおけるインピーダンスが、1.0×10Ω~1.0×1011Ωである。
 すなわち、本態様に係る現像部材によれば、トナーの電荷量のバラつきが非常に小さい現像プロセスが可能になる。
<First requirement>
The slope at a frequency of 1.0 × 10 6 Hz to 1.0 × 10 7 Hz is −0.8 or more and −0.3 or less.
<Second requirement>
The impedance at a frequency of 1.0 × 10 −2 Hz to 1.0 × 10 0 Hz is 1.0 × 10 4 Ω to 1.0 × 10 11 Ω.
That is, according to the developing member according to this aspect, a developing process in which the variation in the charge amount of the toner is extremely small is possible.
 以下、本態様に係る現像部材についての態様を例に説明する。なお、本態様に係る現像部材は、現像ローラに限定されるものでなく、例えば、現像ブレード、トナー供給ローラにも適用し得る。
 本態様に係る現像部材は、導電性の外表面を有する支持体、および、該支持体の外表面上に設けられた導電層を有する。該導電層は、導電性を有する。ここで、導電性とは体積抵抗率が1.0×10Ω・cm未満であると定義する。そして、該導電層は、第一のゴムを含むマトリックスと、該マトリックス中に分散された複数個のドメインとを有し、該ドメインは、第二のゴムおよび電子導電剤を含む。また、該現像部材は、上記の<第一要件>および<第二要件>を満たす。
Hereinafter, an aspect of the developing member according to this aspect will be described as an example. The developing member according to this aspect is not limited to the developing roller, and can be applied to, for example, a developing blade and a toner supply roller.
The developing member according to this aspect includes a support having a conductive outer surface, and a conductive layer provided on the outer surface of the support. The conductive layer has conductivity. Here, the conductivity is defined as having a volume resistivity of less than 1.0 × 10 8 Ω · cm. The conductive layer has a matrix including a first rubber and a plurality of domains dispersed in the matrix, and the domains include a second rubber and an electronic conductive agent. Further, the developing member satisfies the above <first requirement> and <second requirement>.
<第一要件>
 第一の要件は、高周波数側で現像部材内での電荷の停滞が発生し難いことを規定している。
 従来の現像部材のインピーダンスを測定すると、高周波数側で、必ず傾きが-1となる。ここで、傾きとは、図3に示すように、現像部材のインピーダンス特性を周波数に対して両対数プロットした際の、横軸に対する傾きのことである。
 現像部材の等価回路は、電気抵抗Rと静電容量Cの並列回路で表され、インピーダンスの絶対値|Z|は下記式(1)で表現できる。このとき、式(1)内のfは周波数を示す。
Figure JPOXMLDOC01-appb-M000001
 高周波数側で、インピーダンスの傾きが-1の直線になるのは、高周波の電圧に対して電荷の動きが追随できず、停滞するため、電気抵抗値Rが大きく増大した、いわば絶縁の静電容量を計測している状態であると推測できる。電荷が停滞した状態は、式(1)でRを無限大に近似した状態であると、推定することができる。このとき、分母の要素を抜き取った式(2)において、R-2が(2πf)に対して非常に小さい値をとる近似が可能になる。したがって、式(1)はR-2を除去した式(3)のような近似を施した式変形が可能となる。最後に、式(3)に対して両辺対数をとる式変形を行うと、式(4)となり、logfの傾きが-1になる。
Figure JPOXMLDOC01-appb-M000002
<First requirement>
The first requirement stipulates that charge stagnation does not easily occur in the developing member on the high frequency side.
When the impedance of a conventional developing member is measured, the slope is always −1 on the high frequency side. Here, the inclination is an inclination with respect to the horizontal axis when the impedance characteristic of the developing member is log-log plotted against the frequency as shown in FIG.
The equivalent circuit of the developing member is represented by a parallel circuit of an electric resistance R and a capacitance C, and the absolute value | Z | of the impedance can be expressed by the following formula (1). At this time, f in Formula (1) shows a frequency.
Figure JPOXMLDOC01-appb-M000001
On the high frequency side, the impedance slope becomes a straight line of −1 because the movement of electric charges cannot follow the high frequency voltage and stagnates, so that the electric resistance value R has greatly increased. It can be estimated that the capacity is being measured. It can be estimated that the state in which the charge is stagnated is a state in which R is approximated to infinity in Equation (1). At this time, in Expression (2) in which the denominator element is extracted, an approximation is possible in which R- 2 takes a very small value with respect to (2πf) 2 C 2 . Therefore, equation (1) can be modified by approximation such as equation (3) with R -2 removed. Finally, when an equation modification that takes the logarithm of both sides is performed on Equation (3), Equation (4) is obtained, and the slope of logf becomes -1.
Figure JPOXMLDOC01-appb-M000002
 上記式(1)~式(4)の意味を、図4を用いて説明する。図4において、縦軸は、インピーダンスの絶対値の対数、横軸は、測定振動電圧の周波数の対数を示す。図4に、式(1)で表現されるインピーダンスの挙動を示す。まず、上記で説明してきたように、式(1)を満たすインピーダンスは、周波数が大きくなると、ある周波数でその絶対値が低下してくる。そして低下する挙動は、図4のような両対数プロットにおいては、式(4)で示したように、傾きが現像部材の電気抵抗値や静電容量などに依存せずに、―1の傾きの直線となる。
 絶縁性の現像部材のインピーダンス特性を測定すると、傾きが-1の直線となることから、現像部材のインピーダンス測定において、傾きが-1になる状態は、高周波数側で電荷の動きが停滞している特性が現れていると推測される。高周波数側での電荷の動きが停滞すると、通電ための電荷の供給がトナーへの電荷供給の周波数に追随できなくなる。その結果、電荷供給のできないタイミングが生じ、トナー帯電量のバラつきが生じていると推測される。
The meanings of the above formulas (1) to (4) will be described with reference to FIG. In FIG. 4, the vertical axis represents the logarithm of the absolute value of impedance, and the horizontal axis represents the logarithm of the frequency of the measured vibration voltage. FIG. 4 shows the behavior of the impedance expressed by Equation (1). First, as described above, the absolute value of the impedance satisfying the equation (1) decreases as the frequency increases. In the logarithmic plot as shown in FIG. 4, the decreasing behavior is a slope of −1 without depending on the electric resistance value or capacitance of the developing member, as shown by the equation (4). It becomes a straight line.
When the impedance characteristic of the insulating developing member is measured, the slope becomes a straight line of −1. Therefore, in the impedance measurement of the developing member, when the slope is −1, the movement of charge is stagnant on the high frequency side. It is presumed that some characteristics are appearing. If the movement of charge on the high frequency side is stagnant, the supply of charge for energization cannot follow the frequency of charge supply to the toner. As a result, there is a timing at which charge cannot be supplied, and it is assumed that the toner charge amount varies.
 一方、インピーダンスの傾きが、1.0×10Hz~1.0×10Hzの高周波数領域において、-0.8以上、-0.3以下である現像部材は、高周波数側で電荷の供給が停滞し難い。その結果、インピーダンスが一定値をとる低周波数域から高周波数域までの周波数の電荷供給、特に電荷の停滞が生じやすい高周波数側で、電荷の供給を可能にする。電荷の供給が潤沢に実現できるために、トナーへの電荷供給のバラつきを抑制し、トナー帯電量の総量を向上させることができる。当該高周波数領域の範囲は、現像部材から発生する電荷供給の周波数のうちで、最も周波数が大きい領域の通電であるため、トナーへの電荷供給のバラつきが発生しやすい領域であると考えられる。このような周波数領域において傾きが-1よりも大きい上記の範囲の値を示すことで、当該周波数領域より低い高周波数領域においても-1よりも大きい傾きを得て、トナーへの電荷供給のバラつきの発生を抑制し、トナー帯電量の総量を向上させることができる。
 より高速プロセスになるにしたがって、電荷供給の周波数をより高くして放電の回数を増大させる必要があるため、上記範囲の中でも特に、1.0×10Hz~1.0×10Hzの如き高周波数領域における電荷供給および導電機構の制御が重要である。
On the other hand, in the high frequency region where the impedance slope is 1.0 × 10 6 Hz to 1.0 × 10 7 Hz, the developing member having a charge of −0.8 or more and −0.3 or less is charged on the high frequency side. Supply is difficult to stagnate. As a result, it is possible to supply charges at a frequency from a low frequency range where the impedance takes a constant value to a high frequency range, particularly on the high frequency side where charge stagnation is likely to occur. Since a sufficient amount of charge can be realized, variations in charge supply to the toner can be suppressed, and the total amount of toner charge can be improved. The range of the high frequency region is considered to be a region where variations in the charge supply to the toner are likely to occur because the current is supplied in the region having the highest frequency among the charge supply frequencies generated from the developing member. By showing the value in the above-mentioned range in which the slope is larger than −1 in such a frequency region, a slope larger than −1 is obtained even in a high frequency region lower than the frequency region, and the charge supply to the toner varies. Can be suppressed and the total toner charge amount can be improved.
As the process becomes faster, it is necessary to increase the frequency of charge supply and increase the number of discharges. Therefore, in the above range, in particular, 1.0 × 10 6 Hz to 1.0 × 10 7 Hz It is important to control the charge supply and conduction mechanism in such a high frequency range.
 以上のように、トナーへ電荷供給の回数を増大させるためには、高周波数領域におけるインピーダンスの傾きを-1から逸脱させることが有効である。これにより、トナーへ電荷供給とその次の電荷供給のための電荷の供給を迅速に行う特性を良く達成させ得る。インピーダンスの傾きが-1から逸脱することは、現像部材内の電荷の供給が停滞していないことを意味するため、かかる現像部材は、トナーへの電荷供給のバラつきを抑制する方向の特性を得られる。 As described above, in order to increase the number of times of charge supply to the toner, it is effective to deviate the slope of impedance in the high frequency region from -1. As a result, it is possible to satisfactorily achieve the characteristic of rapidly supplying charges to the toner and supplying charges for the subsequent charge supply. When the slope of the impedance deviates from −1, it means that the supply of charge in the developing member is not stagnant. Therefore, the developing member has the characteristic of suppressing the variation in the charge supply to the toner. It is done.
<第二要件>
 第二要件に係る低周波数側のインピーダンスは、電荷の停滞が発生し難いという特性を表しているものである。
 これは、低周波数側のインピーダンスの傾きが-1ではない領域であることからもわかる。そして、式(1)において、周波数をゼロに近似すると、電気抵抗値Rに近似できることから、電気抵抗値Rは、電荷が単一方向に移動する際の能力を表すことが分かる。
 したがって、低周波数の電圧を印可しながらの測定では、電圧の振動に電荷の動きが追随できた状態での電荷の移動量を模擬していると想定できる。
 低周波数における電荷の移動量は、現像部材から測定電極との間での電荷の移動しやすさの指標であり、さらに、現像部材の表面からトナーに対して、通電によって電荷を移動させられる電荷量の指標とすることができる。
 また、第一要件および第二要件に係るインピーダンスの測定に用いられる交流電圧は振幅が1Vである。この測定用の振動電圧は、実際に電子写真方式の画像形成装置の中で現像部材に印可される電圧が数100V~数1000Vであるのに対し大幅に低い。したがって、第一要件および第二要件に係るインピーダンスの測定によって、現像部材の表面からの電荷の出やすさをより高次元で評価できると考えている。
<Second requirement>
The impedance on the low frequency side according to the second requirement represents a characteristic that the stagnation of charges is difficult to occur.
This can also be seen from the region where the slope of impedance on the low frequency side is not -1. In Equation (1), when the frequency is approximated to zero, it can be approximated to the electric resistance value R. Therefore, it can be seen that the electric resistance value R represents the ability to move the charges in a single direction.
Therefore, in the measurement while applying a low-frequency voltage, it can be assumed that the amount of charge movement in a state where the movement of the charge can follow the vibration of the voltage is simulated.
The amount of charge movement at a low frequency is an indicator of the ease of charge transfer between the developing member and the measurement electrode. Further, the charge can be transferred from the surface of the developing member to the toner by energization. It can be an indicator of quantity.
The AC voltage used for the impedance measurement according to the first requirement and the second requirement has an amplitude of 1V. The vibration voltage for measurement is much lower than the voltage actually applied to the developing member in the electrophotographic image forming apparatus is several hundred volts to several thousand volts. Therefore, it is considered that the ease of charge generation from the surface of the developing member can be evaluated in a higher dimension by measuring the impedance according to the first requirement and the second requirement.
 また、第二要件を満たすことで、電荷の出やすさを適切な範囲に制御可能である。インピーダンスが1.0×10Ωより低くなると、一回の供給電荷の量が大きくなりすぎて、次の電荷供給のための電荷の供給が追随できなくなり、電荷供給のバラつきが発生する方向に働き、カブリを抑制することが難しくなる。一方で、インピーダンスが1.0×1011Ωを超えると、電荷の出やすさが低下し、電荷供給のバラつきを埋めるまでの通電量に達しない。
 なお、図4で説明したように現像部材においては、低周波数の領域においては、インピーダンスの絶対値は一定値をとり、1.0×10-2Hz~1.0×10Hzにおけるインピーダンスは、例えば1Hzの周波数におけるインピーダンスの値で代用することができる。
 第一要件と第二要件とを両立する現像部材は、低周波数側から高周波数側までの周波数域においてトナーへの電荷供給のバラつきを抑制して、カブリを低減することが可能となる。第一要件を満たすことで、高周波数側での電荷供給のバラつきを抑制することができる。また、第二要件を満たすことで、供給電荷量がより一層向上し、カブリの発生を効果的に抑制することができる。
In addition, by satisfying the second requirement, it is possible to control the easiness of charge generation within an appropriate range. When the impedance is lower than 1.0 × 10 4 Ω, the amount of charge supplied at one time becomes too large, and the supply of charge for the next charge supply cannot follow and the variation in charge supply occurs. It becomes difficult to work and suppress fogging. On the other hand, when the impedance exceeds 1.0 × 10 11 Ω, the easiness of generating a charge is reduced, and the amount of energization until the charge supply variation is filled is not reached.
As described with reference to FIG. 4, in the developing member, in the low frequency region, the absolute value of the impedance takes a constant value, and the impedance at 1.0 × 10 −2 Hz to 1.0 × 10 0 Hz is For example, an impedance value at a frequency of 1 Hz can be substituted.
The developing member satisfying both the first requirement and the second requirement can suppress the variation in the charge supply to the toner in the frequency range from the low frequency side to the high frequency side and reduce the fog. By satisfying the first requirement, variation in charge supply on the high frequency side can be suppressed. Further, by satisfying the second requirement, the amount of supplied charge can be further improved, and the generation of fog can be effectively suppressed.
<インピーダンスの測定方法>
 現像部材のインピーダンスは次のような方法によって測定することができる。
 インピーダンスの測定に際し、現像部材と測定電極との間の接触抵抗の影響を排除するために、低抵抗な薄膜を現像部材の表面に堆積させ、当該薄膜を電極として使用し、一方で導電性支持体を接地電極として2端子でインピーダンスを測定することが好ましい。
 当該薄膜の形成方法としては、金属蒸着、スパッタリング、金属ペーストの塗布、金属テープを貼付するなどの金属膜の形成方法を挙げることができる。これらの中でも、現像部材との接触抵抗の低減という観点で、白金やパラジウムのような金属薄膜を蒸着によって電極として形成する方法が好ましい。
 現像部材の表面に金属薄膜を形成する場合、その簡便さおよび薄膜の均一性を考慮すると、真空蒸着装置に対して現像部材を把持できる機構を付与し、断面が円柱状の現像部材に対しては、さらに回転機構を付与した、真空蒸着装置を使用することが好ましい。
 現像部材の長手方向で10mm程度の幅の金属薄膜電極を形成し、当該金属薄膜電極に対して隙間なく長手方向に対して交差する方向に巻き付けた金属シートを測定装置から出ている測定電極と接続して測定を行うことが好ましい。円柱状の現像部材の場合では、現像部材の周方向に隙間なく巻き付けた金属シートを用いることが好ましい。これにより、現像部材の長手方向に直交する断面での外縁のサイズ(円柱状の現像部材では外径)の振れや、表面形状に影響されずに、インピーダンス測定を実施することができる。金属シートとしては、アルミホイルや金属テープ等を用いることができる。
 インピーダンスの測定装置は、インピーダンスアナライザ、ネットワークアナライザ、スペクトルアナライザ等、10Hzまでの周波数領域におけるインピーダンスを測定できる装置であればよい。これらの中でも現像部材の電気抵抗域から、インピーダンスアナライザによって測定することが好ましい。
 インピーダンスの測定条件に関して述べる。
 インピーダンス測定の装置を使用し、1.0×10-2Hz~1.0×10Hzの周波数領域におけるインピーダンスを測定する。測定は、温度23℃、相対湿度50%の環境下で行なう。測定ばらつきを低減するために、周波数1桁あたり5点以上の測定点を設け、振動電圧は1Vppである。
<Impedance measurement method>
The impedance of the developing member can be measured by the following method.
When measuring the impedance, in order to eliminate the influence of the contact resistance between the developing member and the measuring electrode, a low-resistance thin film is deposited on the surface of the developing member, and the thin film is used as an electrode while conducting support is supported. It is preferable to measure impedance with two terminals using the body as a ground electrode.
Examples of the method for forming the thin film include metal film forming methods such as metal vapor deposition, sputtering, application of metal paste, and application of metal tape. Among these, from the viewpoint of reducing contact resistance with the developing member, a method of forming a metal thin film such as platinum or palladium as an electrode by vapor deposition is preferable.
When forming a metal thin film on the surface of the developing member, in consideration of the simplicity and uniformity of the thin film, a mechanism capable of gripping the developing member is given to the vacuum deposition apparatus, and the developing member having a cylindrical cross section is provided. It is preferable to use a vacuum deposition apparatus to which a rotation mechanism is further added.
A metal thin film electrode having a width of about 10 mm in the longitudinal direction of the developing member, and a measurement electrode that has a metal sheet wound in a direction intersecting the longitudinal direction with no gap with respect to the metal thin film electrode; It is preferable to connect and perform measurement. In the case of a cylindrical developing member, it is preferable to use a metal sheet that is wound without any gap in the circumferential direction of the developing member. Thereby, impedance measurement can be carried out without being affected by the fluctuation of the outer edge size (outer diameter in the case of a cylindrical developing member) or the surface shape in a cross section orthogonal to the longitudinal direction of the developing member. As the metal sheet, aluminum foil, metal tape, or the like can be used.
The impedance measuring device may be any device that can measure impedance in a frequency region up to 10 7 Hz, such as an impedance analyzer, a network analyzer, and a spectrum analyzer. Among these, it is preferable to measure with an impedance analyzer from the electric resistance region of the developing member.
The impedance measurement conditions will be described.
Using an impedance measurement device, the impedance in the frequency region of 1.0 × 10 −2 Hz to 1.0 × 10 7 Hz is measured. The measurement is performed in an environment at a temperature of 23 ° C. and a relative humidity of 50%. In order to reduce measurement variation, five or more measurement points are provided for each digit of the frequency, and the oscillating voltage is 1 Vpp.
 測定電圧に関しては、電子写真装置内の現像部材に印可される分担電圧を考慮して直流電圧を印可しながら測定してもよい。具体的には、10V以下の直流電圧を振動電圧と重畳印可しながらの測定が電荷の輸送と蓄積の特性を定量化するために好適である。
 次に、インピーダンスの傾きの算出方法について述べる。
 上記の条件で測定した測定結果に対し、Windowsエクセル(登録商標)のような表計算ソフトを使用して、インピーダンスの絶対値を、測定周波数に対して両対数グラフでプロットする。この両対数プロットで得られたグラフの、1.0×10Hz~1.0×10Hzの周波数領域におけるインピーダンスの絶対値の傾きを、1.0×10Hz~1.0×10Hzの周波数領域の測定点を利用して求めればよい。具体的には、当該周波数範囲のグラフのプロットに対し、一次関数の近似直線を最小二乗法で算出し、その傾きを算出すればよい。
 次いで、当該両対数グラフ内の1.0×10-2Hz~1.0×10Hzの周波数領域における測定点での算術平均値を算出し、得られた値を低周波数側のインピーンダンスとすればよい。
 インピーダンスの傾きの測定では、現像部材の長手方向を5等分した際のそれぞれの領域内の任意の場所で測定を5か所行い、5か所の傾きの測定値の算術平均を算出すればよい。
The measurement voltage may be measured while applying a DC voltage in consideration of a shared voltage applied to the developing member in the electrophotographic apparatus. Specifically, measurement while applying a DC voltage of 10 V or less to the vibration voltage is suitable for quantifying the charge transport and accumulation characteristics.
Next, a method for calculating the slope of impedance will be described.
For the measurement results measured under the above conditions, the absolute value of the impedance is plotted in a log-log graph with respect to the measurement frequency using a spreadsheet software such as Windows Excel (registered trademark). The slope of the absolute value of the impedance in the frequency region of 1.0 × 10 6 Hz to 1.0 × 10 7 Hz of the graph obtained by this log-log plot is 1.0 × 10 6 Hz to 1.0 ×. What is necessary is just to obtain | require using the measuring point of a 10 < 7 > Hz frequency range. Specifically, an approximate straight line of a linear function may be calculated by a least square method with respect to a plot of the graph in the frequency range, and the slope may be calculated.
Next, the arithmetic average value at the measurement point in the frequency region of 1.0 × 10 −2 Hz to 1.0 × 10 0 Hz in the log-log graph is calculated, and the obtained value is used as the low frequency input impedance. Just dance.
In the measurement of the slope of the impedance, if the longitudinal direction of the developing member is divided into five equal parts, the measurement is performed at five locations in each area, and the arithmetic average of the measured values at the five locations is calculated. Good.
(1)現像部材
 本態様に係る電子写真用の現像部材は、導電性支持体と、支持体上の少なくとも一層の導電層を有する。
 一例として、ローラ形状の現像部材(現像ローラ)を図1に示す。図1に示す現像ローラ1Aは、導電性支持体2と、その外周面(外表面)に設けられた導電層3とを有する。現像ローラ1Aにおいて、本発明の一実施形態に係る効果をより効果的に奏するためには、図1に示すように、導電層3が現像ローラ1Aの唯一の層として、支持体2に直接設けられていることが好ましい。
 なお、現像ローラ1Aの層の構成は、図1に示される形態に限定されるものではない。現像ローラ1Aの他の形態としては、図5に示すように、支持体2とその外周面に設けられた導電層3の間に、中間層53を有する現像ローラ1Cが挙げられる。
 また、電子写真用の現像部材の他の態様としては、ブレード形状を有する現像部材(以降、「現像ブレード」ともいう)が挙げられる。
 図2は、現像ブレード1Bの概略断面図である。図2に示す現像ブレード1Bは、導電性支持体2と、支持体2の外表面の端部を含む一部の領域に設けられた導電層3とから構成されている。
 現像ブレード1Bは、導電層3を、支持体の一部となる導電性のステンレス鋼製シートの先端部に被覆し、ステンレス鋼製シートの後端部を導電性支持体2に溶接する構成とすることもできる。
 現像部材は、現像ローラ、現像スリーブ、現像ブレード、トナー供給ローラに用いることが可能である。
(1) Developing member The developing member for electrophotography according to this embodiment has a conductive support and at least one conductive layer on the support.
As an example, a roller-shaped developing member (developing roller) is shown in FIG. A developing roller 1A shown in FIG. 1 includes a conductive support 2 and a conductive layer 3 provided on an outer peripheral surface (outer surface) thereof. In order to achieve the effect of the embodiment of the present invention more effectively in the developing roller 1A, as shown in FIG. 1, the conductive layer 3 is provided directly on the support 2 as the only layer of the developing roller 1A. It is preferable that
The configuration of the layer of the developing roller 1A is not limited to the form shown in FIG. As another form of the developing roller 1A, as shown in FIG. 5, there is a developing roller 1C having an intermediate layer 53 between the support 2 and the conductive layer 3 provided on the outer peripheral surface thereof.
Another embodiment of the electrophotographic developing member includes a developing member having a blade shape (hereinafter also referred to as “developing blade”).
FIG. 2 is a schematic cross-sectional view of the developing blade 1B. A developing blade 1B shown in FIG. 2 includes a conductive support 2 and a conductive layer 3 provided in a partial region including an end portion of the outer surface of the support 2.
The developing blade 1B has a configuration in which the conductive layer 3 is coated on the leading end of a conductive stainless steel sheet that is a part of the support, and the trailing end of the stainless steel sheet is welded to the conductive support 2. You can also
The developing member can be used for a developing roller, a developing sleeve, a developing blade, and a toner supply roller.
 以下、本発明の一実施形態に係る現像部材の構成を詳細に説明する。
<導電性支持体>
 導電性支持体2は、現像部材の支持部材、および場合によっては電極として機能する。支持体の具体例について、現像部材がローラ形状である場合、支持体2は、中実円柱状または中空円筒状であり、現像部材がブレード形状である場合、支持体2は、薄板形状である。
 導電性支持体を構成する材料としては、電子写真用の導電性部材の分野で公知なものや、かかる現像部材として利用できる材料から適宜選択して用いることができる。一例として、アルミニウム、ステンレスに代表される金属、炭素鋼合金、導電性を有する合成樹脂、鉄、銅合金などの金属または合金が挙げられる。さらに、これらに対して、酸化処理やクロム、ニッケルなどで鍍金処理を施しても良い。鍍金の種類としては電気鍍金、無電解鍍金のいずれも使用することができる。寸法安定性の観点から無電解鍍金が好ましい。ここで使用される無電解鍍金の種類としては、ニッケル鍍金、銅鍍金、金鍍金、その他各種合金鍍金を挙げることができる。鍍金厚さは、0.05μm以上が好ましく、作業効率と防錆能力のバランスを考慮すると、鍍金厚さは0.1μm~30μmであることが好ましい。
 支持体と導電層の間に、中抵抗層、あるいは絶縁層が存在すると、通電による電荷の消費後の電荷の供給を迅速にできなくなる。よって、導電層は、支持体に直接設けるか、あるいは、プライマーのごとき、薄膜、かつ、導電性の樹脂層からなる中間層のみを介して支持体の外周に導電層を設けることが好ましい。
 プライマーとしては、導電層形成用のゴム材料および支持体の材質等に応じて公知のものを選択して用いることができる。プライマーの材料としては、例えば熱硬化性樹脂や熱可塑性樹脂が挙げられ、具体的には、フェノール系樹脂、ウレタン樹脂、アクリル樹脂、ポリエステル樹脂、ポリエーテル樹脂、エポキシ樹脂の如き材料を用い得る。
 樹脂層および支持体のインピーダンスは、周波数が1.0×10-2Hz~1.0×10Hzにおいて、1.0×10-5Ω~1.0×10Ωの範囲であることが好ましい。
 低周波数におけるインピーダンスが上記範囲の支持体および樹脂層であれば、導電層に対し、十分な電荷の供給を実施でき、導電層に含まれるマトリックスドメイン構造の、第一要件と第二要件による放電の抜けを抑制する機能が阻害されないため好ましい。
 樹脂層のインピーダンスは、最外表面に存在する導電層を剥離して行うこと以外は、上記のインピーダンスの傾きの測定と同様の方法によって測定することができる。また、支持体のインピーダンスは、樹脂層または導電層を被覆する前の状態で、あるいは、現像ローラ形成後は、導電層、あるいは樹脂層と導電層からなる被覆層を剥離した状態で、上記のインピーダンスの測定と同様の方法により測定することができる。
Hereinafter, the structure of the developing member according to an embodiment of the present invention will be described in detail.
<Conductive support>
The conductive support 2 functions as a support member for the developing member and, in some cases, an electrode. Regarding specific examples of the support, when the developing member has a roller shape, the support 2 has a solid columnar shape or a hollow cylindrical shape, and when the developing member has a blade shape, the support 2 has a thin plate shape. .
The material constituting the conductive support can be appropriately selected from materials known in the field of electrophotographic conductive members and materials usable as such developing members. As an example, metals or alloys such as aluminum, stainless steel, carbon steel alloys, conductive synthetic resins, iron, copper alloys, and the like can be given. Further, these may be subjected to an oxidation treatment or a plating treatment with chromium, nickel or the like. As the type of plating, either electric plating or electroless plating can be used. From the viewpoint of dimensional stability, electroless plating is preferable. Examples of the electroless plating used here include nickel plating, copper plating, gold plating, and other various alloy platings. The plating thickness is preferably 0.05 μm or more, and the plating thickness is preferably 0.1 μm to 30 μm in consideration of the balance between work efficiency and rust prevention ability.
If a medium resistance layer or an insulating layer exists between the support and the conductive layer, it becomes impossible to quickly supply the charge after the charge is consumed by energization. Therefore, it is preferable to provide the conductive layer directly on the support or to provide the conductive layer on the outer periphery of the support only through an intermediate layer made of a thin film and a conductive resin layer, such as a primer.
As a primer, a well-known thing can be selected and used according to the rubber material for conductive layer formation, the material of a support body, etc. Examples of the primer material include thermosetting resins and thermoplastic resins. Specifically, materials such as phenol resins, urethane resins, acrylic resins, polyester resins, polyether resins, and epoxy resins can be used.
The impedance of the resin layer and the support is in the range of 1.0 × 10 −5 Ω to 1.0 × 10 1 Ω at a frequency of 1.0 × 10 −2 Hz to 1.0 × 10 0 Hz. Is preferred.
If the support and the resin layer have a low frequency impedance within the above range, a sufficient charge can be supplied to the conductive layer, and the discharge according to the first and second requirements of the matrix domain structure contained in the conductive layer. This is preferable because the function of suppressing the omission is not hindered.
The impedance of the resin layer can be measured by the same method as the measurement of the impedance slope described above, except that the conductive layer existing on the outermost surface is peeled off. Further, the impedance of the support is as described above in a state before coating the resin layer or the conductive layer, or after the development roller is formed, in a state where the conductive layer or the coating layer made of the resin layer and the conductive layer is peeled off. It can be measured by the same method as the impedance measurement.
<導電層>
 前記<第一要件>および<第二要件>を満たす現像部材としては、例えば、導電層が、以下の構成(i)~構成(iii)のうちの少なくとも1つの構成を満たす現像部材が好ましい。
(i)該マトリックスの体積抵抗率が、1.0×1012Ω・cmより大きく1.0×1017Ω・cm以下であること。
(ii)該ドメインの体積抵抗率が、1.0×10Ω・cm以上、1.0×10Ω・cm以下であること。
(iii)該ドメインの隣接壁面間距離が、0.2μm以上、2.0μm以下の範囲内であること。
 以下、上記(i)~(iii)の要素について説明する。
 図6に、導電性ローラの長手方向に対して垂直な方向の導電層の部分断面図を示す。導電層6は、マトリックス6aとドメイン6bとを有するマトリックス-ドメイン構造を有する。そして、ドメイン6bは、電子導電剤としての電子導電剤6cを含む。
 このように電子導電剤を含むドメインがマトリックス中に分散されている導電層を具備する現像部材に導電性支持体と他部材との間にバイアスが印加されたときの導電層内において、電荷は以下のようにして導電層の導電性支持体側から反対側、すなわち、現像部材の外表面側に移動すると考えられる。すなわち、電荷は、ドメイン中のマトリックスとの界面近傍に蓄積される。そして、その電荷は、導電性支持体側に位置するドメインから、導電性支持体の側とは反対側に位置するドメインに順次受け渡されていき、導電層の導電性支持体の側とは反対側の表面(以降、「導電層の外表面」ともいう)に到達する。このとき、1回の電荷供給工程で全てのドメインの電荷が導電層の外表面側に移動すると、次の電荷供給工程に向けて、導電層中に電荷を蓄積するために時間を要することとなる。すなわち、高速の電子写真画像形成プロセスに対応することが困難となる。したがって、バイアスが印加されてもドメイン間の電荷の授受が同時的に生じないようにすることが好ましい。また、電荷の動きが制約される高周波数領域においても、1回の電荷供給で十分な量の電荷を供給させるためには、ドメインに十分な量の電荷を蓄積させることが有効となる。
 以上述べたように、バイアス印加時のドメイン間での同時的な電荷の授受の発生を抑制し、かつ、ドメイン内に十分な電荷を蓄積させるために、マトリックスの体積抵抗率を1.0×1012Ω・cmより大きく1.0×1017Ω・cm以下とすること(構成(i))、ドメインの体積抵抗率が、1.0×10Ω・cm以上、1.0×10Ω・cm以下とすること(構成(ii))、および、ドメイン間の隣接壁面間距離を0.2μm以上、2.0μm以下の範囲内とすること(構成(iii))のうちの少なくとも一つを満たすことが好ましい。
<Conductive layer>
As the developing member that satisfies the <first requirement> and the <second requirement>, for example, a developing member in which the conductive layer satisfies at least one of the following configurations (i) to (iii) is preferable.
(I) The volume resistivity of the matrix is greater than 1.0 × 10 12 Ω · cm and 1.0 × 10 17 Ω · cm or less.
(Ii) The volume resistivity of the domain is 1.0 × 10 1 Ω · cm or more and 1.0 × 10 4 Ω · cm or less.
(Iii) The distance between adjacent wall surfaces of the domain is in the range of 0.2 μm or more and 2.0 μm or less.
Hereinafter, the elements (i) to (iii) will be described.
FIG. 6 shows a partial cross-sectional view of the conductive layer in a direction perpendicular to the longitudinal direction of the conductive roller. The conductive layer 6 has a matrix-domain structure having a matrix 6a and a domain 6b. The domain 6b includes an electronic conductive agent 6c as an electronic conductive agent.
Thus, in the conductive layer when a bias is applied between the conductive support and the other member to the developing member including the conductive layer in which the domain containing the electronic conductive agent is dispersed in the matrix, the charge is It is considered that it moves from the conductive support side of the conductive layer to the opposite side, that is, the outer surface side of the developing member as follows. That is, charge is accumulated near the interface with the matrix in the domain. The electric charge is sequentially transferred from the domain located on the conductive support side to the domain located on the opposite side of the conductive support side, and is opposite to the conductive support side of the conductive layer. To the side surface (hereinafter also referred to as the “outer surface of the conductive layer”). At this time, if the charges of all domains move to the outer surface side of the conductive layer in one charge supply step, it takes time to accumulate the charges in the conductive layer for the next charge supply step. Become. That is, it becomes difficult to cope with a high-speed electrophotographic image forming process. Therefore, it is preferable that charge transfer between domains does not occur simultaneously even when a bias is applied. Further, even in a high frequency region where the movement of charges is restricted, it is effective to accumulate a sufficient amount of charges in a domain in order to supply a sufficient amount of charges with a single charge supply.
As described above, the volume resistivity of the matrix is set to 1.0 × in order to suppress the occurrence of simultaneous charge transfer between domains during bias application and to accumulate sufficient charges in the domains. More than 10 12 Ω · cm and 1.0 × 10 17 Ω · cm or less (configuration (i)), the volume resistivity of the domain is 1.0 × 10 1 Ω · cm or more, 1.0 × 10 4 Ω · cm or less (configuration (ii)) and at least a distance between adjacent wall surfaces between domains within a range of 0.2 μm or more and 2.0 μm or less (configuration (iii)) It is preferable to satisfy one.
<構成(i)>
・マトリックスの体積抵抗率;
 マトリックスの体積抵抗率を、1.0×1012Ω・cmより大きく1.0×1017Ω・cm以下とすることで、電荷が、ドメインを迂回してマトリックス内を移動することを抑制できる。また、ドメインに蓄積された電荷が、マトリックスに漏洩することによって、あたかも導電層内を連通する導電経路が形成されているかの如き状態となることを防止できる。
 前記<第一要件>に関し、高周波数のバイアス印加下でも導電層中を、ドメインを介して電荷を移動させるためには、電荷が十分に蓄積された領域(ドメイン)が、電気的に絶縁性の領域(マトリックス)で分断されている構成が有効であると本発明者らは考えている。そして、マトリックスの体積抵抗率を上記したような高抵抗領域の範囲とすることで、各ドメインとの界面において十分な電荷を留めることができ、また、ドメインからの電荷漏洩を抑制できる。
 また、前記<第二要件>を満たす導電層とするためには、電荷の移動経路が、ドメインを介在した経路に限定することが効果的であることを見出した。ドメインからのマトリックスへの電荷の漏洩を抑制し、電荷の輸送経路を複数のドメインを介した経路に限定することにより、ドメインに存在する電荷の密度を向上させることができるため、各ドメインにおける電荷の充填量をより増大させることができる。これにより、通電の起点である導電相としてのドメインの表面において、通電に関与できる電荷の総数を向上させることができ、結果、現像部材の表面からの電荷の出やすさを向上させることができると考えられる。
<Configuration (i)>
The volume resistivity of the matrix;
By setting the volume resistivity of the matrix to be larger than 1.0 × 10 12 Ω · cm and not more than 1.0 × 10 17 Ω · cm, it is possible to suppress the electric charge from moving around in the matrix around the domain. . In addition, it is possible to prevent the electric charge accumulated in the domain from leaking into the matrix so that a state as if a conductive path communicating in the conductive layer is formed.
Regarding the <first requirement>, in order to move charges through a domain in a conductive layer even under application of a high frequency bias, a region (domain) in which charges are sufficiently accumulated is electrically insulating. The present inventors consider that the structure divided by the region (matrix) is effective. Then, by setting the volume resistivity of the matrix within the range of the high resistance region as described above, sufficient charges can be retained at the interface with each domain, and charge leakage from the domain can be suppressed.
Further, the present inventors have found that in order to obtain a conductive layer that satisfies the <second requirement>, it is effective to limit the charge transfer path to a path through a domain. By suppressing the leakage of charge from the domain to the matrix and limiting the charge transport path to the path through multiple domains, the density of charges existing in the domain can be improved. The filling amount can be further increased. As a result, the total number of charges that can be involved in energization can be improved on the surface of the domain as the conductive phase, which is the starting point of energization, and as a result, the ease with which charges are generated from the surface of the developing member can be improved. it is conceivable that.
<マトリックスの体積抵抗率の測定方法>
 マトリックスの体積抵抗率は、当該現像部材を薄片化し、微小探針によって計測することができる。薄片化する手段としては、例えば、鋭利なカミソリや、ミクロトーム、収束イオンビーム法(FIB)などがあげられる。
 薄片の作製に関しては、ドメインの影響を排除し、マトリックスのみの体積抵抗率を計測する必要があるため、走査型電子顕微鏡(SEM)や透過型電子顕微鏡(TEM)などであらかじめ計測したドメイン間距離よりも小さい膜厚の薄片を作成する必要がある。したがって、薄片化の手段としては、ミクロトームのような非常に薄いサンプルを作成できる手段が好ましい。
 体積抵抗率の測定は、まず、当該薄片の片面を接地した後に、薄片中のマトリックスとドメインの場所を特定する。この場所の特定には、走査型プローブ顕微鏡(SPM)、原子間力顕微鏡(AFM)などで、マトリックスとドメインの体積抵抗率あるいは硬度の分布を計測できる手段を用いることができる。次いで、当該マトリックスに探針を接触させ、10VのDC電圧を印可したときの接地電流を測定し、電気抵抗として算出すればよい。このとき、薄片のSPMやAFMのような形状測定も可能な手段であれば、当該薄片の膜厚が計測でき、体積抵抗率が測定可能であるため、好適である。
 円柱状の現像部材におけるマトリックスの体積抵抗率の測定は、導電層を周方向に4分割、長手方向に5分割した領域のそれぞれから各1つずつ薄片サンプルを切り出し、上記の測定値を得た後に、合計20サンプルの体積抵抗率の算術平均値を算出することによって行なうことができる。
<Measuring method of volume resistivity of matrix>
The volume resistivity of the matrix can be measured by thinning the developing member and using a microprobe. Examples of the thinning means include a sharp razor, a microtome, and a focused ion beam method (FIB).
For the production of flakes, it is necessary to eliminate the influence of the domain and measure the volume resistivity of the matrix only, so the inter-domain distance measured in advance with a scanning electron microscope (SEM), transmission electron microscope (TEM), etc. It is necessary to create a flake with a smaller film thickness. Therefore, as a thinning means, a means capable of producing a very thin sample such as a microtome is preferable.
The volume resistivity is measured by first grounding one side of the slice and then specifying the location of the matrix and domain in the slice. For specifying the location, means capable of measuring the volume resistivity or hardness distribution of the matrix and the domain with a scanning probe microscope (SPM), an atomic force microscope (AFM) or the like can be used. Next, a probe is brought into contact with the matrix, and a ground current when a DC voltage of 10 V is applied is measured and calculated as an electric resistance. At this time, any means capable of measuring the shape such as SPM or AFM of the thin piece is preferable because the film thickness of the thin piece can be measured and the volume resistivity can be measured.
The measurement of the volume resistivity of the matrix in the cylindrical developing member was performed by cutting out a thin sample one by one from each of the regions obtained by dividing the conductive layer into 4 parts in the circumferential direction and 5 parts in the longitudinal direction, and obtained the above measured values. Later, this can be done by calculating the arithmetic mean value of the volume resistivity of a total of 20 samples.
<構成(ii)>
・ドメインの体積抵抗率;
 ドメインの体積抵抗率は1.0×10Ω・cm以上、1.0×10Ω・cm以下にすることが好ましい。ドメインの体積抵抗率をより低い状態にすることで、マトリックスで目的としない電荷の移動を抑制しつつ、電荷の輸送経路を、より効果的に複数のドメインを介する経路に限定することができる。
 さらに、ドメインの体積抵抗率は、1.0×10Ω・cm以下であることがより好ましい。ドメインの体積抵抗率を当該範囲まで下げることで、ドメイン内で移動する電荷の量を飛躍的に向上できるため、周波数が1.0×10-2Hz~1.0×10Hzにおける導電層のインピーダンスを、1.0×10Ω以下のさらに低い範囲に制御でき、さらに効果的に電荷の輸送経路をドメイン経由に限定することができる。
 ドメインの体積抵抗率は、ドメインのゴム成分に対し、導電剤を使用することによって、その導電性を所定の値にすることで調整する。
 ドメイン用のゴム材料としては、マトリックス用としてのゴム成分を含むゴム組成物を用いることができるが、マトリックスドメイン構造を形成するためにマトリックスを形成するゴム材料との溶解度パラメータ(SP値)の差が、0.4(J/cm0.5以上、5.0(J/cm0.5以下、特には、0.4(J/cm0.5以上、2.2(J/cm0.5以下にすることがより好ましい。
 ドメインの体積抵抗率は、電子導電剤の種類、およびその添加量を適宜選択することによって調整することができる。ドメインの体積抵抗率を1.0×10Ω・cm以上、1.0×10Ω・cm以下に制御するために使用する導電剤としては、分散する量によって高抵抗から低抵抗まで体積抵抗率を大きく変化させることができる電子導電剤が好ましい。
 ドメインに配合される電子導電剤については、カーボンブラック、グラファイト、酸化チタン、酸化錫等の酸化物;Cu、Ag等の金属;酸化物または金属が表面に被覆され導電化された粒子等を例として挙げられる。また、必要に応じて、これらの導電剤の2種類以上を適宜量配合して使用しても良い。
 以上の様な電子導電剤のうち、ゴムとの親和性が大きく、電子導電剤間の距離の制御が容易な、導電性のカーボンブラックを使用することが好ましい。ドメインに配合されるカーボンブラックの種類については、特に限定されるものではない。具体的には、例えば、ガスファーネスブラック、オイルファーネスブラック、サーマルブラック、ランプブラック、アセチレンブラック、ケッチェンブラック等が挙げられる。
<Configuration (ii)>
-Volume resistivity of the domain;
The volume resistivity of the domain is preferably 1.0 × 10 1 Ω · cm or more and 1.0 × 10 4 Ω · cm or less. By setting the volume resistivity of the domain to a lower state, it is possible to more effectively limit the charge transport path to a path through a plurality of domains while suppressing unintended charge movement in the matrix.
Furthermore, the volume resistivity of the domain is more preferably 1.0 × 10 2 Ω · cm or less. By reducing the volume resistivity of the domain to the above range, the amount of charge moving in the domain can be dramatically improved, so that the conductive layer has a frequency of 1.0 × 10 −2 Hz to 1.0 × 10 0 Hz Can be controlled to a lower range of 1.0 × 10 5 Ω or less, and the charge transport path can be more effectively limited to the domain.
The volume resistivity of the domain is adjusted by setting the conductivity to a predetermined value by using a conductive agent for the rubber component of the domain.
As the rubber material for the domain, a rubber composition containing a rubber component for the matrix can be used, but a difference in solubility parameter (SP value) from the rubber material forming the matrix in order to form a matrix domain structure. 0.4 (J / cm 3 ) 0.5 or more, 5.0 (J / cm 3 ) 0.5 or less, particularly 0.4 (J / cm 3 ) 0.5 or more, 2.2 (J / cm 3 ) More preferably 0.5 or less.
The volume resistivity of the domain can be adjusted by appropriately selecting the type of electronic conductive agent and the amount of addition thereof. As a conductive agent used for controlling the volume resistivity of the domain to 1.0 × 10 1 Ω · cm or more and 1.0 × 10 4 Ω · cm or less, the volume from high resistance to low resistance is varied depending on the amount of dispersion. An electronic conductive agent capable of greatly changing the resistivity is preferable.
Examples of the electronic conductive agent blended in the domain include oxides such as carbon black, graphite, titanium oxide, and tin oxide; metals such as Cu and Ag; and particles that are conductively coated with oxide or metal on the surface As mentioned. Moreover, you may mix | blend and use 2 or more types of these electrically conductive agents suitably as needed.
Of the electronic conductive agents as described above, it is preferable to use conductive carbon black that has a large affinity with rubber and can easily control the distance between the electronic conductive agents. The type of carbon black blended in the domain is not particularly limited. Specific examples include gas furnace black, oil furnace black, thermal black, lamp black, acetylene black, and ketjen black.
 中でも、高い導電性をドメインに付与し得る、DBP吸油量が40cm/100g以上、170cm/100g以下である導電性カーボンブラックを好適に用いることができる。
 導電性のカーボンブラック等の電子導電剤は、ドメインに含まれるゴム成分の100質量部に対して、20質量部以上、150質量部以下でドメインに配合されることが好ましい。特に好ましい配合割合は、50質量部以上、100質量部以下である。これらの割合での導電剤の配合は、一般的な電子写真用の導電性部材と比較して、導電剤が多量に配合されていることが好ましい。これにより、ドメインの体積抵抗率を1.0×10Ω・cm以上、1.0×10Ω・cm以下の範囲に容易に制御することができる。
 ドメインに用いる導電剤としてイオン導電剤を電子導電剤と併用しても良い。
 イオン導電剤としては、例えば、第4級アンモニウム塩、イミダゾリウム塩、ピリジニウム塩などを使うことができる。イオン導電剤のアニオンとしては、過塩素酸アニオン、フルオロアルキルスルホニルイミドアニオン、フルオロスルホニルイミドアニオン、トリフルオロメタンスルホネートアニオン、テトラフルオロボレートアニオンなどが挙げられる。これらの少なくとも1種を用いることができる。
Among them, can impart high conductivity to the domain, DBP oil absorption of 40 cm 3/100 g or more can be suitably used conductive carbon black is not more than 170cm 3 / 100g.
The electronic conductive agent such as conductive carbon black is preferably blended in the domain at 20 to 150 parts by mass with respect to 100 parts by mass of the rubber component contained in the domain. A particularly preferable blending ratio is 50 parts by mass or more and 100 parts by mass or less. In the blending of the conductive agent at these ratios, it is preferable that a large amount of the conductive agent is blended as compared with a general electrophotographic conductive member. Thereby, the volume resistivity of the domain can be easily controlled in the range of 1.0 × 10 1 Ω · cm or more and 1.0 × 10 4 Ω · cm or less.
An ionic conductive agent may be used in combination with an electronic conductive agent as a conductive agent used for the domain.
As the ionic conductive agent, for example, a quaternary ammonium salt, an imidazolium salt, a pyridinium salt, or the like can be used. Examples of the anion of the ionic conductive agent include perchlorate anion, fluoroalkylsulfonylimide anion, fluorosulfonylimide anion, trifluoromethanesulfonate anion, tetrafluoroborate anion, and the like. At least one of these can be used.
 また、必要に応じて、ゴムの配合剤として一般に用いられている充填剤、加工助剤、架橋助剤、架橋促進剤、老化防止剤、架橋促進助剤、架橋遅延剤、軟化剤、分散剤、着色剤等を、本発明に係る効果を阻害しない範囲でドメイン用のゴム組成物に添加してもよい。
・ドメインの体積抵抗率の測定方法;
 ドメインの体積抵抗率の測定は、上記のマトリックスの体積抵抗率の測定方法に対して、測定箇所をドメインに相当する場所に変更し、電流値の測定の際の印可電圧を1Vに変更した以外は同様の方法で実施すればよい。
 ここで、ドメインの体積抵抗率は、均一であることが好ましい。ドメインの体積抵抗率の均一性を向上させるためには、各ドメイン内の電子導電剤の量を均一化することが好ましい。これにより、導電性部材の外表面からの、被帯電体への放電をより安定化させることができる。
If necessary, fillers, processing aids, crosslinking aids, crosslinking accelerators, anti-aging agents, crosslinking promotion aids, crosslinking retarders, softeners, dispersants generally used as rubber compounding agents Further, a colorant and the like may be added to the rubber composition for a domain as long as the effects according to the present invention are not impaired.
-Measuring method of volume resistivity of the domain;
The volume resistivity of the domain is measured except that the measurement location is changed to a location corresponding to the domain, and the applied voltage at the time of measuring the current value is changed to 1 V, in contrast to the volume resistivity measurement method of the matrix. May be carried out in the same manner.
Here, the volume resistivity of the domain is preferably uniform. In order to improve the uniformity of the volume resistivity of the domains, it is preferable to equalize the amount of the electronic conductive agent in each domain. Thereby, the discharge to the to-be-charged body from the outer surface of the conductive member can be further stabilized.
<構成(iii)>
・ドメイン間の隣接壁面間距離(以降、「ドメイン間距離」ともいう)
 ドメイン間距離の算術平均値Dmが、0.2μm以上、2.0μm以下であることが好ましい。
 構成(i)に係る体積抵抗率を有するマトリックス中に、構成(ii)に係る体積抵抗率のドメインが分散されている導電層が、前記<第二要件>を満たすようにするために、ドメイン間距離の算術平均値Dmを2.0μm以下、特には、1.0μm以下とすることが好ましい。一方、ドメイン同士を絶縁領域で確実に分断することで、十分な電荷をドメインに蓄積させるためには、ドメイン間距離の算術平均値Dmを、0.2μm以上、特には、0.3μm以上とすることが好ましい。
・ドメイン間距離の測定方法;
 ドメイン間距離の測定方法は、次のように実施すればよい。
 まず、前述のマトリックスの体積抵抗率の測定における方法と同様の方法で切片を作製する。次いで、凍結割断法、クロスポリッシャー法、収束イオンビーム法(FIB)等の手段で破断面を形成する。破断面の平滑性と、観察のための前処理を考慮すると、FIB法が好ましい。また、マトリックスドメイン構造の観察を好適に実施するために、染色処理、蒸着処理など、導電相と絶縁相とのコントラストが好適に得られる前処理を施してもよい。
 破断面の形成、前処理を行った切片を、走査型電子顕微鏡(SEM)や透過型電子顕微鏡(TEM)によって観察して、マトリックスドメイン構造の存在を確認する。これらの中でも、ドメインの面積の定量化の正確性から、SEMで1000倍~100000倍で観察を行うことが好ましい。
 ドメイン間距離の測定は、マトリックス-ドメイン構造が現れている破断面の撮影画像を定量化することによって行なうことが好ましい。SEMでの観察により得られた破断面画像に対し、画像処理ソフト(例えば、「Luzex」(商品名、ニレコ社製))を使用して、8ビットのグレースケール化を行い、256諧調のモノクロ画像を得る。次いで、破断面内のドメインが白くなるように、画像の白黒を反転処理し、2値化を実施する。次いで、画像内のドメインサイズ群の壁面間距離を算出する。このときの壁面間距離は、近接したドメイン間の最短距離である。
 円柱状の現像部材の場合では、導電層の長手方向の長さをL、導電層の厚さをTとしたとき、導電層の長手方向の中央、および導電層の両端から中央に向かってL/4の3か所における、図8Bに示されるような導電層の厚さ方向の断面を取得する。得られた断面の各々について、導電層の外表面から支持体方向への深さ0.1T~0.9Tまでの厚み領域の任意の3か所に50μm四方の観察領域を置き、この全9個の観察領域の各々で観察される各ドメイン間距離を測定すればよい。切片は、電荷の移動方向である支持体から導電層外表面を含む面を観察することが必要であることから、支持体の中心軸を起点とする法線を含む断面を観察することができる方向で切り出す。なお、導電層の厚さTが100μm以上であることが好ましい。
<Configuration (iii)>
-Distance between adjacent walls between domains (hereinafter also referred to as "inter-domain distance")
The arithmetic average value Dm of the distance between domains is preferably 0.2 μm or more and 2.0 μm or less.
In order that the conductive layer in which the volume resistivity domain according to the configuration (ii) is dispersed in the matrix having the volume resistivity according to the configuration (i) satisfies the above-mentioned <second requirement>. The arithmetic average value Dm of the distance is preferably 2.0 μm or less, and more preferably 1.0 μm or less. On the other hand, in order to accumulate sufficient charges in the domains by reliably dividing the domains into the insulating regions, the arithmetic average value Dm of the inter-domain distance is 0.2 μm or more, particularly 0.3 μm or more. It is preferable to do.
・ Measuring method of distance between domains;
What is necessary is just to implement the measuring method of the distance between domains as follows.
First, a slice is prepared by the same method as that used in the measurement of the volume resistivity of the matrix. Next, a fracture surface is formed by means such as a freezing cleaving method, a cross polisher method, or a focused ion beam method (FIB). The FIB method is preferable in consideration of the smoothness of the fracture surface and pretreatment for observation. Further, in order to preferably observe the matrix domain structure, a pretreatment such as a dyeing treatment or a vapor deposition treatment that can suitably obtain the contrast between the conductive phase and the insulating phase may be performed.
The section subjected to the formation of the fracture surface and the pretreatment is observed with a scanning electron microscope (SEM) or a transmission electron microscope (TEM) to confirm the presence of the matrix domain structure. Among these, from the accuracy of quantification of the area of the domain, it is preferable to observe with a SEM at 1000 to 100,000 times.
The distance between domains is preferably measured by quantifying a photographed image of a fracture surface where a matrix-domain structure appears. An image processing software (for example, “Luzex” (trade name, manufactured by Nireco)) is used for the fracture surface image obtained by observation with the SEM, and the gray scale is converted to 8-bit monochrome. Get an image. Next, the black and white of the image is inverted so that the domain in the fracture surface becomes white, and binarization is performed. Next, the distance between the wall surfaces of the domain size group in the image is calculated. The distance between the wall surfaces at this time is the shortest distance between adjacent domains.
In the case of a cylindrical developing member, when the length of the conductive layer in the longitudinal direction is L and the thickness of the conductive layer is T, the length in the longitudinal direction of the conductive layer and the distance from both ends of the conductive layer toward the center are L. A cross section in the thickness direction of the conductive layer as shown in FIG. For each of the obtained cross-sections, 50 μm square observation regions were placed at any three locations in the thickness region from the outer surface of the conductive layer to the depth of 0.1 T to 0.9 T in the direction of the support. What is necessary is just to measure the distance between each domain observed in each of the observation regions. Since the slice needs to observe the surface including the outer surface of the conductive layer from the support in the direction of charge movement, a cross section including the normal line starting from the central axis of the support can be observed. Cut out by direction. Note that the thickness T of the conductive layer is preferably 100 μm or more.
・ドメイン間距離の均一性;
 上記構成(iii)に関して、ドメイン間距離の分布は均一であることが、より好ましい。ドメイン間の距離の分布が均一であることで、導電層内で局所的にドメイン間距離が長い箇所が一部できることによって、電荷の供給が周囲比べて滞る箇所が生じた場合などに、電荷の出やすさが抑制される現象を低減できる。
 電荷が輸送される断面、すなわち、図8Bに示されるような導電層の厚さ方向の断面において、導電層の外表面から支持体方向への深さ0.1T~0.9Tまでの厚み領域の任意の3か所における、50μm四方の観察領域を取得した際に、当該観察領域内のドメイン間距離の算術平均値Dmおよびドメイン間距離のばらつきσmを用いてσm/Dmが0以上、0.4以下であることが好ましい。
<ドメイン間距離の制御方法>
 ドメイン間距離の制御法について以下に説明する。
 非相溶のポリマー2種を溶融混練させた場合のドメイン間距離(1/τ)について、Taylorの式(式(5))およびWuの経験式(式(6)および式(7))を基にしたTokitaの理論式(式(8))が提案されている。
・Taylorの式
   D=[C・σ/ηm・γ]・f(ηm/ηd)    (5)
・Wuの経験式
  γ・D・ηm/σ=4(ηd/ηm)0.84・ηd/ηm>1   (6)
  γ・D・ηm/σ=4(ηd/ηm)-0.84・ηd/ηm<1  (7)
・Tokitaの式
 D=12・P・σ・φ/(π・η・γ)・(1+4・P・φ・EDK/(π・η・γ))(8)
 式(5)~式(8)において、Dは、CMBのドメインの最大フェレ径、Cは、定数、σは、界面張力、ηmは、マトリックスの粘度、ηdは、ドメインの粘度、γは、せん断速度、ηは、混合系の粘度、Pは、衝突合体確率、φは、ドメイン相体積、EDKは、ドメイン相切断エネルギーを表す。
 上記式に示す通りに、ドメイン間距離は、主に、
(A)ドメイン相の体積比、
(B)ドメインとマトリックスの粘度比、
(C)せん断速度、
(D)ドメイン相切断エネルギーの大きさ
で制御することが可能である。
 具体的に、ドメイン間距離を低減するには以下の手法で制御が可能である。
・ドメインポリマーとマトリックスポリマー間の界面張力を小さくする。
・ドメインポリマーとマトリックスポリマー間の粘度差を低減する。
・混練時のせん断速度を上げる/せん断時のエネルギーを上げる。
・ドメイン相の体積比を上げる。
・衝突合体確率を下げる。
 上述の通りに、ドメイン間距離の制御は、ドメインサイズの制御と同時に進行するが、ドメイン相の体積比や衝突合体確率、即ち、混練時間やせん断速度の制御によって、独立にドメイン間距離の制御が可能である。
 高速プロセス下でも導電パスにおける電荷の移動をより効率的に行うためには、電気抵抗の揃った導電性のドメインを三次元的に均等かつ密に導電層中に配置させることで、極めて均一でムラのない導電パスを有する構成とすることがより好ましい。
 具体的には、該導電層の厚み方向の断面に現れるドメインの各々の断面積に対する該ドメインの各々が含む導電性粒子からなる部分の断面積の割合の平均値をμとし、該割合の標準偏差をσとしたとき、σ/μが、0以上、0.4以下であり、μが20%以上、40%以下であることが好ましい。これらのσおよびμの条件に加えて、導電層の任意の9箇所からサンプリングされる、合計9個の一辺が9μmの立方体形状のサンプル立方体のうち、少なくとも8個のサンプル立方体は、下記要件(B1)を満たすことが特に好ましい。
 要件(B1):
 「1個のサンプル立方体を、27個の、一辺が3μmの単位立方体に区分し、該単位立方体の各々に含まれる前記ドメインの体積Vdを求めたとき、Vdが2.7μm~10.8μmである単位立方体の数が少なくとも20個であること。」
・ Uniformity of distance between domains;
Regarding the configuration (iii), it is more preferable that the distribution of the inter-domain distance is uniform. The distribution of the distance between domains is uniform, so that a portion where the distance between domains is locally long in the conductive layer can be partially created, resulting in a charge stagnation when there is a place where charge supply is delayed compared to the surroundings. It is possible to reduce the phenomenon that the ease of taking out is suppressed.
In the cross section where the charge is transported, that is, the cross section in the thickness direction of the conductive layer as shown in FIG. 8B, the thickness region from the outer surface of the conductive layer to the depth of 0.1T to 0.9T from the outer surface of the conductive layer When an observation area of 50 μm square at any three locations is acquired, σm / Dm is 0 or more using the arithmetic average value Dm of the interdomain distance in the observation area and the variation σm of the interdomain distance. .4 or less is preferable.
<Method for controlling the distance between domains>
A method for controlling the distance between domains will be described below.
For the interdomain distance (1 / τ) when two incompatible polymers are melt-kneaded, Taylor's formula (formula (5)) and Wu's empirical formula (formula (6) and formula (7)) are Tokita's theoretical formula (formula (8)) based on this has been proposed.
Taylor equation D = [C · σ / ηm · γ] · f (ηm / ηd) (5)
Wu's empirical formula γ · D · ηm / σ = 4 (ηd / ηm) 0.84 · ηd / ηm> 1 (6)
γ · D · ηm / σ = 4 (ηd / ηm) −0.84 · ηd / ηm <1 (7)
・ Tokita's formula D = 12 ・ P ・ σ ・ φ / (π ・ η ・ γ) ・ (1 + 4 ・ P ・ φ ・ EDK / (π ・ η ・ γ)) (8)
In the equations (5) to (8), D is the maximum ferret diameter of the CMB domain, C is a constant, σ is the interfacial tension, ηm is the matrix viscosity, ηd is the domain viscosity, and γ is The shear rate, η is the viscosity of the mixed system, P is the collision coalescence probability, φ is the domain phase volume, and EDK is the domain phase cutting energy.
As shown in the above formula, the interdomain distance is mainly
(A) the volume ratio of the domain phase,
(B) Viscosity ratio of domain to matrix
(C) shear rate,
(D) It is possible to control by the magnitude of the domain phase cutting energy.
Specifically, the following method can be used to reduce the distance between domains.
-Reduce the interfacial tension between the domain polymer and the matrix polymer.
Reduce the viscosity difference between the domain polymer and the matrix polymer.
Increase the shear rate during kneading / increase the energy during shearing.
-Increase the volume ratio of the domain phase.
・ Lower the collision coalescence probability.
As described above, the control of the interdomain distance proceeds simultaneously with the control of the domain size, but the control of the interdomain distance is independently performed by controlling the volume ratio of the domain phase and the collision coalescence probability, that is, the kneading time and shear rate. Is possible.
In order to more efficiently transfer charges in the conductive path even under high-speed processes, conductive domains with uniform electrical resistance are arranged in a conductive layer three-dimensionally uniformly and densely. More preferably, the conductive path has no unevenness.
Specifically, the average value of the ratio of the cross-sectional area of the portion made of conductive particles included in each domain to the cross-sectional area of each domain appearing in the cross section in the thickness direction of the conductive layer is μ, and the standard of the ratio When the deviation is σ, σ / μ is preferably 0 or more and 0.4 or less, and μ is preferably 20% or more and 40% or less. In addition to these conditions of σ and μ, at least 8 sample cubes out of a total of 9 sample cubes each having a side of 9 μm sampled from any 9 locations of the conductive layer have the following requirements ( It is particularly preferable to satisfy B1).
Requirement (B1):
“When one sample cube is divided into 27 unit cubes each having a side of 3 μm, and the volume Vd of the domain included in each unit cube is obtained, Vd is 2.7 μm 3 to 10.8 μm. The number of unit cubes that are 3 must be at least 20. "
 本発明者らは、電気抵抗の揃った導電性のドメインが三次元的に均等かつ密に導電層中に配置された、極めて均一でムラのない導電パスを有する電子写真用の現像部材において、高速プロセス下でも導電パスにおける電荷の移動をより効率的に行うことが可能となる要因として、以下のメカニズムを推定している。
 バイアスを付加する方式の現像部材においては、電荷密度の異なるトナーに対して、ブレードニップ内で現像・除電を行い均一な電荷密度に現像させる事が望ましく、そのため現像ブレードの表面電位をトナーサイズで均一に保ち続ける必要がある。よって導電パスが導電性支持体から現像部材表面に亘って厚み方向ならびに面内方向に均質にかつ、高密度に形成されていることが好ましい。
 上記μとσの関係が、『σ/μが、0以上、0.4以下』であると、各ドメイン中に含まれる導電剤からなる部分(例えば導電性粒子)の数・量にバラつきがなくなる。その結果、電気抵抗の揃ったドメインとなる。特に、上記μとσの関係が、『σ/μが、0以上、0.25以下』の場合にはさらに電気抵抗の揃ったドメインとなるため、より本発明における効果が高まる傾向があるため特に好ましい。
 σ/μを低い値にするためには、各ドメイン中に含まれる導電性粒子からなる部分数・量を増加させることが好ましく、またドメインのサイズを揃えることも好ましい。
 なお、ここでμは、20%以上、40%以下が好ましい。後述するように、μが20%未満である場合には、導電性粒子の量が必然的に少なく、ドメイン内での導電性粒子の電気的な繋がりがパーコレーション的に不安定になる場合などがある。一方、μが40%よりも多い場合には、ドメイン内の導電性粒子の量が多くなるため導電性粒子をドメイン内に閉じ込めにくくなる場合などがある。また、後述するとおり、ドメイン内の導電性粒子の充填量が増すと、本発明の効果が高まることを見出しており、より好ましくは、μは、23%以上、さらに好ましくは28%以上である。
 加えて、上記の一辺が3μmの単位立方体中にドメインが10体積%~40体積%含まれ、かつサンプル立方体が導電層全体に均質に存在するため、導電性のドメインが三次元的に均等かつ密に導電層中に配置された構成となる。なお、後述するように、ドメインの総体積を増加させた場合にも、導電層全体に均質に存在する割合が高まる傾向がある。また、ドメインの総体積が同じでも、ドメインサイズを小さくし、個数を増加させることで、ドメインが該導電層全体に均質に存在する割合が飛躍的に高まる傾向がある。
 つまり、上記要件(B1)を満たす一辺が3μmの単位立方体の個数が増加すると、必然的に本発明の効果が高まる。したがって、27個の単位立方体のうちの、Vdが2.7μm~10.8μmである単位立方体の数が20個以上であることが好ましく、22個以上であることがより好ましく、25個以上であることがさらに好ましい。
 なお、言うまでもないことであるが、導電支持体から導電層の表面まで導電パスが繋がって形成されるためには3次元的にドメインを配置する必要がある。言い換えると、ある二次元断面でのドメイン配置の制御だけでは、導電支持体から導電層の表面までの導電パスの繋がりを正確に構築することができない。なお、ここで『導電パスが繋がっている』とは、所望の印加電圧に伴い、該導電パスを形成しているドメイン間を電荷が効率よく移動(ホッピング伝導やトンネル伝導やバンド伝導性など)できる状態を指す。用いる印加電圧や導電層の厚み、さらにはドメインやマトリックスの電気抵抗によるが、3次元的な評価において、ドメインの隣接壁面間距離が2.0μm以下であることが特に好ましい。
 本態様に係る現像部材は、例えば、下記工程(i)~工程(iv)を含む方法を経て形成することができる。
In the developing member for electrophotography having a conductive path with extremely uniform and non-uniformity in which conductive domains with uniform electrical resistance are arranged in a conductive layer three-dimensionally and uniformly in a conductive layer, The following mechanism is estimated as a factor that makes it possible to move charges in a conductive path more efficiently even under a high-speed process.
In a developing member that applies a bias, it is desirable to develop and remove the charge in the blade nip to develop a uniform charge density for toners having different charge densities. It is necessary to keep it uniform. Therefore, it is preferable that the conductive paths are formed uniformly and densely in the thickness direction and in the in-plane direction from the conductive support to the developing member surface.
When the relationship between μ and σ is “σ / μ is 0 or more and 0.4 or less”, the number and amount of portions (for example, conductive particles) made of a conductive agent contained in each domain vary. Disappear. As a result, a domain with uniform electrical resistance is obtained. In particular, when the relationship between μ and σ is “σ / μ is 0 or more and 0.25 or less”, the domain becomes more uniform in electrical resistance, and thus the effect of the present invention tends to increase. Particularly preferred.
In order to reduce σ / μ, it is preferable to increase the number and amount of the conductive particles contained in each domain, and it is also preferable to make the sizes of the domains uniform.
Here, μ is preferably 20% or more and 40% or less. As will be described later, when μ is less than 20%, the amount of the conductive particles is inevitably small, and the electrical connection of the conductive particles in the domain may become percolation unstable. is there. On the other hand, when μ is larger than 40%, the amount of conductive particles in the domain increases, so that it may be difficult to confine the conductive particles in the domain. Further, as will be described later, it has been found that the effect of the present invention is enhanced when the amount of conductive particles in the domain is increased. More preferably, μ is 23% or more, and more preferably 28% or more. .
In addition, since the above-mentioned unit cube having a side of 3 μm contains 10% by volume to 40% by volume of the domain and the sample cube exists uniformly in the entire conductive layer, the conductive domain is three-dimensionally uniform and The structure is densely arranged in the conductive layer. As will be described later, even when the total volume of the domains is increased, the ratio of being present uniformly in the entire conductive layer tends to increase. Even if the total volume of the domains is the same, there is a tendency that the ratio of the domains uniformly existing in the entire conductive layer is dramatically increased by reducing the domain size and increasing the number of domains.
That is, when the number of unit cubes each having a side of 3 μm that satisfies the requirement (B1) is increased, the effect of the present invention is inevitably enhanced. Accordingly, among the 27 pieces of unit cubes, preferably Vd is 2.7 .mu.m 3 ~ 10.8 3 a is the number of unit cube 20 or more, more preferably 22 or more, 25 More preferably, it is the above.
Needless to say, in order to form a conductive path connected from the conductive support to the surface of the conductive layer, it is necessary to arrange the domains three-dimensionally. In other words, the connection of the conductive path from the conductive support to the surface of the conductive layer cannot be accurately established only by controlling the domain arrangement in a certain two-dimensional cross section. Here, “the conductive path is connected” means that the electric charge efficiently moves between domains forming the conductive path with a desired applied voltage (hopping conduction, tunnel conduction, band conduction, etc.) It refers to the state that can be done. Depending on the applied voltage used, the thickness of the conductive layer, and the electrical resistance of the domain or matrix, the distance between adjacent wall surfaces of the domain is particularly preferably 2.0 μm or less in a three-dimensional evaluation.
The developing member according to this aspect can be formed, for example, through a method including the following steps (i) to (iv).
 工程(i):カーボンブラックおよび第二のゴムを含む、ドメイン形成用ゴム混合物(以降、「CMB」とも称する)を調製する工程;
 工程(ii):第一のゴムを含むマトリックス形成用ゴム混合物(以降、「MRC」とも称する)を調製する工程;
 工程(iii):CMBとMRCとを混練して、マトリックス-ドメイン構造を有するゴム混合物を調製する工程。
 工程(iv):工程(iii)で調製したゴム混合物の層を、導電性支持体上に直接または他の層を介して形成し、該ゴム組成物の層を硬化させて、本態様に係る導電層を形成する工程。
 そして、構成(i)~構成(iii)は、例えば、上記各工程に用いる材料の選択、製造条件の調整により制御することができる。以下説明する。
 まず、構成(i)に関して、マトリックスの体積抵抗率は、MRCの組成によって定まる。
 MRCに用いる第一のゴムとしては、導電性の低い、天然ゴム、ブタジエンゴム、ブチルゴム、アクリロニトリルブタジエンゴム、ウレタンゴム、シリコーンゴム、フッ素ゴム、イソプレンゴム、クロロプレンゴム、スチレン-ブタジエンゴム、エチレン-プロピレンゴム、ポリノルボルネンゴムの如きゴムの少なくとも1種を用い得る。また、MRCには、マトリックスの体積抵抗率を上記範囲内にすることができることを前提として、必要に応じて、充填剤、加工助剤、架橋剤、架橋助剤、架橋促進剤、架橋促進助剤、架橋遅延剤、老化防止剤、軟化剤、分散剤、着色剤を添加してもよい。一方、MRCには、マトリックスの体積抵抗率を上記範囲内とするために、カーボンブラックの如き電子導電剤は含有させないことが好ましい。
 また、構成(ii)は、CMB中の電子導電剤の量によって調整し得る。例えば、電子導電剤として、DBP吸油量が、40cm/100g以上、170cm/100g以下である導電性カーボンブラックを用いる場合を例に挙げると、CMBの全質量を基準として、40質量%以上、200質量%以下の導電性カーボンブラックを含むようにCMBを調製することで構成(ii)を達成し得る。
Step (i): preparing a domain-forming rubber mixture (hereinafter also referred to as “CMB”) containing carbon black and a second rubber;
Step (ii): preparing a matrix-forming rubber mixture (hereinafter also referred to as “MRC”) containing the first rubber;
Step (iii): A step of preparing a rubber mixture having a matrix-domain structure by kneading CMB and MRC.
Step (iv): A layer of the rubber mixture prepared in step (iii) is formed directly or via another layer on the conductive support, and the layer of the rubber composition is cured, and this embodiment is applied. Forming a conductive layer;
The configurations (i) to (iii) can be controlled by, for example, selecting materials used in the above steps and adjusting manufacturing conditions. This will be described below.
First, regarding the configuration (i), the volume resistivity of the matrix is determined by the composition of the MRC.
The first rubbers used in MRC are low conductivity, natural rubber, butadiene rubber, butyl rubber, acrylonitrile butadiene rubber, urethane rubber, silicone rubber, fluorine rubber, isoprene rubber, chloroprene rubber, styrene-butadiene rubber, ethylene-propylene. At least one rubber such as rubber and polynorbornene rubber can be used. In addition, in MRC, on the premise that the volume resistivity of the matrix can be within the above range, a filler, a processing aid, a cross-linking agent, a cross-linking aid, a cross-linking accelerator, a cross-linking promotion aid are provided as necessary. An agent, a crosslinking retarder, an anti-aging agent, a softener, a dispersant, and a colorant may be added. On the other hand, in order to make the volume resistivity of the matrix within the above range, the MRC preferably does not contain an electronic conductive agent such as carbon black.
Further, the configuration (ii) can be adjusted by the amount of the electronic conductive agent in the CMB. For example, as an electron conductive agent, DBP oil absorption amount, 40 cm 3/100 g or more, taking as an example the case of using a conductive carbon black is not more than 170cm 3/100 g, based on the total weight of the CMB, 40 wt% or more The composition (ii) can be achieved by preparing CMB so as to contain 200% by mass or less of conductive carbon black.
 さらに、構成(iii)に関しては、下記(a)~(d)の4つを制御することが有効である。
 (a)CMB、およびMRCの各々の界面張力σの差;
 (b)CMBの粘度(ηd)、およびMRCの粘度(ηm)の比(ηm/ηd);
 (c)工程(iii)における、CMBとMRCとの混練時のせん断速度(γ)、およびせん断時のエネルギー量(EDK)。
 (d)工程(iii)における、CMBのMRCに対する体積分率。
 (a)CMBとMRCとの界面張力差
 一般的に二種の非相溶のゴムを混合した場合、相分離する。これは、異種高分子間の相互作用よりも、同一高分子間の相互作用が強いため、同一高分子同士で凝集し、自由エネルギーを低下させ安定化しようとするためである。相分離構造の界面は異種高分子と接触するため、同一分子同士の相互作用で安定化されている内部より、自由エネルギーが高くなる。その結果、界面の自由エネルギーを低減させるために、異種高分子と接触する面積を小さくしようとする界面張力が発生する。この界面張力が小さい場合、エントロピーを増大させるために異種高分子でもより均一に混合しようとする方向に向かう。均一に混合した状態とは溶解であり、溶解度の目安となるSP値(溶解度パラメーター)と界面張力は相関する傾向にある。
 つまり、CMBとMRCとの界面張力差は、CMBおよびMRCの界面張力は、各々が含むゴムのSP値差と相関すると考えられる。MRC中の第一のゴムと、CMB中の第二のゴムとしては、溶解度パラメーターの絶対値の差が、0.4(J/cm0.5以上、5.0(J/cm0.5以下、特には、0.4(J/cm0.5以上、2.2(J/cm0.5以下となるようなゴムを選択することが好ましい。この範囲であれば安定した相分離構造を形成でき、また、CMBのドメイン径Dを小さくすることができる。
 ここで、CMBに用い得る第二のゴムの具体例としては、例えば、天然ゴム(NR)、イソプレンゴム(IR)、ブタジエンゴム(BR)、スチレン-ブタジエンゴム(SBR)、ブチルゴム(IIR)、エチレン-プロピレンゴム(EPM、EPDM)、クルルプレンゴム(CR)、ニトリルゴム(NBR)、水素添加ニトリルゴム(H-NBR)、シリコーンゴム、ウレタンゴム(U)が挙げられる。これらの少なくとも1種を用いることができる。
 導電層の厚みは、目的とする導電性部材の機能および効果が得られるものであれば特に限定されない。導電層の厚みは、少なくとも100μm(0.1mm)以上とすることが好ましく、特には、0.3mm以上、更には、1.0mm以上とすることが好ましい。また、4.5mm以下とすることが好ましい。
Further, regarding the configuration (iii), it is effective to control the following four (a) to (d).
(A) difference in interfacial tension σ of each of CMB and MRC;
(B) Ratio (ηm / ηd) of CMB viscosity (ηd) and MRC viscosity (ηm);
(C) Shear rate (γ) when kneading CMB and MRC in step (iii) and energy amount (EDK) during shearing.
(D) Volume fraction of CMB relative to MRC in step (iii).
(A) Interfacial tension difference between CMB and MRC Generally, when two types of incompatible rubbers are mixed, phase separation occurs. This is because the interaction between the same polymers is stronger than the interaction between the different polymers, and therefore, the same polymers are aggregated to reduce free energy and stabilize. Since the interface of the phase separation structure is in contact with a different polymer, the free energy is higher than the interior stabilized by the interaction between the same molecules. As a result, in order to reduce the free energy at the interface, an interfacial tension is generated that attempts to reduce the area in contact with the different polymer. When this interfacial tension is small, in order to increase entropy, even different types of polymers tend to be mixed more uniformly. The uniformly mixed state is dissolution, and the SP value (solubility parameter) that is a measure of solubility and the interfacial tension tend to correlate.
That is, the interfacial tension difference between CMB and MRC is considered to correlate with the SP value difference between the rubbers contained in each interfacial tension between CMB and MRC. For the first rubber in MRC and the second rubber in CMB, the difference in the absolute value of the solubility parameter is 0.4 (J / cm 3 ) 0.5 or more, 5.0 (J / cm 3 It is preferable to select a rubber that is 0.5 or less, in particular 0.4 (J / cm 3 ) 0.5 or more and 2.2 (J / cm 3 ) 0.5 or less. Within this range, a stable phase separation structure can be formed, and the domain diameter D of CMB can be reduced.
Here, specific examples of the second rubber that can be used for CMB include, for example, natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), butyl rubber (IIR), Examples thereof include ethylene-propylene rubber (EPM, EPDM), kuruprene rubber (CR), nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), silicone rubber, and urethane rubber (U). At least one of these can be used.
The thickness of the conductive layer is not particularly limited as long as the intended function and effect of the conductive member can be obtained. The thickness of the conductive layer is preferably at least 100 μm (0.1 mm) or more, particularly 0.3 mm or more, and more preferably 1.0 mm or more. Moreover, it is preferable to set it as 4.5 mm or less.
<SP値の測定方法>
 SP値は、SP値が既知の材料を用いて、検量線を作成することで、精度良く算出することが可能である。この既知のSP値は、材料メーカーのカタログ値を用いることもできる。例えば、NBRおよびSBRは、分子量に依存せず、アクリロニトリルおよびスチレンの含有比率でSP値がほぼ決定される。したがって、マトリックスおよびドメインを構成するゴムを、熱分解ガスクロマトグラフィー(Py-GC)および固体NMR等の分析手法を用いて、アクリロニトリルまたはスチレンの含有比率を解析することで、SP値が既知の材料から得た検量線から、SP値を算出することができる。また、イソプレンゴムは、1,2-ポリイソプレン、1,3-ポリイソプレン、3,4-ポリイソプレン、およびcis-1,4-ポリイソプレン、trans-1,4-ポリイソプレンなどの、異性体構造でSP値が決定される。したがって、SBRおよびNBRと同様にPy-GCおよび固体NMR等で異性体含有比率を解析し、SP値が既知の材料から、SP値を算出することができる。
(b)CMBとMRCとの粘度比
 CMBとMRCとの粘度比(ηd/ηm)は、1に近い程、ドメインの最大フェレ径を小さくできる。具体的には、粘度比は1.0以上、2.0以下であることが好ましい。CMBとMRCの粘度比は、CMBおよびMRCに使用する原料ゴムのムーニー粘度の選択や、充填剤の種類や量の配合によって調整が可能である。また、相分離構造の形成を妨げない程度に、パラフィンオイルなどの可塑剤を添加することでも可能である。また混練時の温度を調整することで、粘度比の調整を行うことができる。なおドメイン形成用ゴム混合物やマトリックス形成用ゴム混合物の粘度は、JIS K6300-1:2013に基づきムーニー粘度ML(1+4)を混練時のゴム温度で測定することで得られる。
(c)MRCとCMBとの混練時のせん断速度、およびせん断時のエネルギー量
 MRCとCMBとの混練時のせん断速度は速いほど、また、せん断時のエネルギー量は大きいほど、ドメイン間距離を小さくすることができる。
 せん断速度は、混練機のブレードやスクリュウといった撹拌部材の内径を大きくし、撹拌部材の端面から混練機内壁までの間隙を小さくすることや、回転数を大きくすることで上げることができる。またせん断時のエネルギーを上げるには、撹拌部材の回転数を上げることや、CMB中の第一のゴムとMRC中の第二のゴムの粘度を上げることで達成できる。
(d)MRCに対するCMBの体積分率
 MRCに対するCMBの体積分率は、マトリックス形成用ゴム混合物に対するドメイン形成用ゴム混合物の衝突合体確率と相関する。具体的には、マトリックス形成用ゴム混合物に対するドメイン形成用ゴム混合物の体積分率を低減させると、ドメイン形成用ゴム混合物とマトリックス形成用ゴム混合物の衝突合体確率が低下する。つまり必要な導電性を得られる範囲において、マトリックス中におけるドメインの体積分率を減らすことでドメイン間距離を小さくできる。そして、CMBのMRCに対する体積分率は、15%以上、40%以下とすることが好ましい。
<SP value measurement method>
The SP value can be accurately calculated by creating a calibration curve using a material whose SP value is known. The catalog value of the material manufacturer can also be used for this known SP value. For example, NBR and SBR do not depend on the molecular weight, and the SP value is almost determined by the content ratio of acrylonitrile and styrene. Therefore, a material having a known SP value can be obtained by analyzing the content ratio of acrylonitrile or styrene of rubber constituting the matrix and domain using an analysis method such as pyrolysis gas chromatography (Py-GC) and solid-state NMR. The SP value can be calculated from the calibration curve obtained from the above. The isoprene rubber is composed of isomers such as 1,2-polyisoprene, 1,3-polyisoprene, 3,4-polyisoprene, and cis-1,4-polyisoprene and trans-1,4-polyisoprene. The SP value is determined by the structure. Therefore, similarly to SBR and NBR, the isomer content ratio can be analyzed by Py-GC, solid NMR, etc., and the SP value can be calculated from a material having a known SP value.
(B) Viscosity ratio between CMB and MRC As the viscosity ratio (ηd / ηm) between CMB and MRC is closer to 1, the maximum ferret diameter of the domain can be reduced. Specifically, the viscosity ratio is preferably 1.0 or more and 2.0 or less. The viscosity ratio between CMB and MRC can be adjusted by selecting the Mooney viscosity of the raw rubber used for CMB and MRC and by blending the type and amount of filler. It is also possible to add a plasticizer such as paraffin oil to the extent that it does not interfere with the formation of the phase separation structure. The viscosity ratio can be adjusted by adjusting the temperature at the time of kneading. The viscosity of the rubber mixture for forming a domain and the rubber mixture for forming a matrix can be obtained by measuring Mooney viscosity ML (1 + 4) at the rubber temperature at the time of kneading based on JIS K6300-1: 2013.
(C) Shear rate during kneading of MRC and CMB, and energy amount during shearing As the shear rate during kneading of MRC and CMB is faster, and as the energy amount during shearing is larger, the inter-domain distance decreases. can do.
The shear rate can be increased by increasing the inner diameter of the stirring member such as the blade or screw of the kneading machine, reducing the gap from the end face of the stirring member to the inner wall of the kneading machine, or increasing the rotational speed. Further, increasing the energy during shearing can be achieved by increasing the number of revolutions of the stirring member or by increasing the viscosity of the first rubber in the CMB and the second rubber in the MRC.
(D) Volume fraction of CMB relative to MRC The volume fraction of CMB relative to MRC correlates with the collision coalescence probability of the domain forming rubber mixture relative to the matrix forming rubber mixture. Specifically, when the volume fraction of the domain-forming rubber mixture with respect to the matrix-forming rubber mixture is reduced, the collision coalescence probability between the domain-forming rubber mixture and the matrix-forming rubber mixture is lowered. In other words, the inter-domain distance can be reduced by reducing the volume fraction of domains in the matrix within a range where necessary conductivity can be obtained. And it is preferable that the volume fraction with respect to MRC of CMB shall be 15% or more and 40% or less.
<ドメインの形状>
 ドメインの形状は、円形に近いほうが好ましい。ドメインの面積と、ドメインの最大フェレ径相当の円の面積との比が0.6以上、1以下であることが好ましい。この比は1が最大値であり、1である状態は、ドメインが真円であることを示す。これら比が0.6より小さいと、ドメインの形状が異方性を有することとなり、すなわち、電界の異方性が発現する。これにより、電界集中点が形成されるため、電荷の輸送の集中が生じるため、持続性の大きい放電が起きやすい。これらの比が1に近づくほど、当該電界集中が抑制されるため、カブリ画像が発生しにくくなる。
 なお、最大フェレ径とは、観察されたドメインの外周を2本の平行線で挟み、その2本の平行線間を垂線で結んだときの長さが最も長くなる時の値である。また、最大フェレ径相当の円とは、この最大フェレ径を直径とする円である。
<ドメイン面積S1、最大フェレ径相当円の面積S2の測定方法>
 ドメインの形状は、上記のドメインのサイズやドメイン間距離を測定する手法と同様の手法で、破断面の作成および観察を行って得られる画像を使って定量化することが可能である。具体的には、上記ドメインサイズの測定方法と同様の方法で、破断面内の2値化を行った後に、画像処理ソフトを用いて、画像内のドメインのそれぞれに対し、ドメイン面積と最大フェレ径を算出する。次いで、実ドメイン面積S1と、最大フェレ径から得られる、最大フェレ径相当円の面積S2との比を求めればよい。
 S1およびS2の測定では、現像部材を均等に、好ましくは20区画に均等に分割した領域のそれぞれから各1つずつ薄片サンプルを切り出し、上記の測定値を得た後に、合計20サンプルのS1、S2の算術平均値をS1、S2の測定値とすればよい。
 円柱状の現像部材の場合では、円柱状の周方向に4分割、長手方向に5分割した領域のそれぞれから各1つずつ薄片サンプルを切り出し、上記の測定値を得た後に、合計20サンプルのS1,S2の算術平均値を、S1、S2の測定値とすればよい。
<Shape of domain>
The shape of the domain is preferably close to a circle. The ratio of the area of the domain to the area of a circle corresponding to the maximum ferret diameter of the domain is preferably 0.6 or more and 1 or less. This ratio has a maximum value of 1 and a state of 1 indicates that the domain is a perfect circle. When these ratios are smaller than 0.6, the shape of the domain has anisotropy, that is, the anisotropy of the electric field appears. As a result, an electric field concentration point is formed, and the concentration of charge transport occurs, so that a highly sustainable discharge is likely to occur. The closer these ratios are to 1, the more the electric field concentration is suppressed, and thus fog images are less likely to occur.
The maximum ferret diameter is a value when the outer circumference of the observed domain is sandwiched between two parallel lines and the length when the two parallel lines are connected by a perpendicular line is the longest. The circle corresponding to the maximum ferret diameter is a circle having the maximum ferret diameter as a diameter.
<Measuring Method of Domain Area S1, Area S2 of Maximum Feret Diameter Equivalent Circle>
The shape of the domain can be quantified using an image obtained by creating and observing the fracture surface by a method similar to the method of measuring the size of the domain and the distance between the domains. Specifically, after binarizing the fracture surface in the same manner as the domain size measurement method described above, the domain area and maximum ferrule are obtained for each domain in the image using image processing software. Calculate the diameter. Next, a ratio between the actual domain area S1 and the area S2 of the circle corresponding to the maximum ferret diameter obtained from the maximum ferret diameter may be obtained.
In the measurement of S1 and S2, slice samples were cut out one by one from each of the regions obtained by dividing the developing member equally, preferably equally into 20 sections, and after obtaining the above measured values, a total of 20 samples of S1, The arithmetic average value of S2 may be the measured values of S1 and S2.
In the case of a cylindrical developing member, a slice sample is cut out from each of the regions divided into four in the cylindrical circumferential direction and five in the longitudinal direction, and after obtaining the above measured values, a total of 20 samples are obtained. The arithmetic average value of S1 and S2 may be the measured values of S1 and S2.
 また導電剤の凝集による抵抗変動と電界集中を抑制し、本発明の効果をより効率的に奏するために、導電層は、導電層の長手方向の長さをLとしたとき、導電層の長手方向の中央、および導電層の両端から中央に向かってL/4の3か所における、導電層の厚さ方向の断面の各々について、弾性層の外表面から深さ0.1T~0.9Tまでの厚み領域の任意の3か所に15μm四方の観察領域を置いたときに、全9個の該観察領域の各々で観察されるドメインのうちの80個数%以上が、下記要件(B2)および要件(B3)を満たすことが好ましい。
 要件(B2)
 ドメインの断面積に対する該ドメインが含む該導電性粒子の断面積の割合が、20%以上であること
 要件(B3)
 ドメインの周囲長をA、該ドメインの包絡周囲長をBとしたとき、A/Bが、1.00以上、1.10以下であること。
 上記要件(B2)および要件(B3)は、ドメインの形状に係る規定ということができる。「ドメインの形状」とは、導電層の厚さ方向の断面に現れたドメインの断面形状として定義される。円柱形状の帯電部材の場合では、導電層の長手方向の長さをL、導電層の厚さをTとしたとき、導電層の長手方向の中央、および導電層の両端から中央に向かってL/4の3か所における、図8Bに示されるような導電層の厚さ方向の断面を取得する。得られた断面の各々について、導電層の外表面から支持体方向への深さ0.1T~0.9Tまでの厚み領域の任意の3か所に15μm四方の観察領域を置く。ドメイン形状は、この全9個の観察領域の各々で観察される各ドメインの形状で定義される。
 ドメインの形状はその周面に凹凸がない形状であることが好ましい。形状に関する凹凸構造の数を低減することによって、ドメイン間の電界の不均一性を低減でき、つまり、電界集中が生じる箇所を少なくして、マトリックスで必要以上の電荷輸送が起きる現象を低減できる。本発明者は、1個のドメインに含まれる導電性粒子の量が、当該ドメインの外形形状に影響を与えているとの知見を得た。
 すなわち、1個のドメインの導電性粒子の充填量が増えるにつれて、該ドメインの外形形状がより球体に近くなるとの知見を得た。球体に近いドメインの数が多いほど、ドメイン間での電子の授受の集中点を少なくすることができる。そして、本発明者らの検討によれば、その理由は明らかでないが、1つのドメインの断面の面積を基準として、当該断面において観察される導電性粒子の断面積の総和の割合が20%以上であるドメインは、より、球体に近い形状を取り得る。その結果、ドメイン間での電子の授受の集中を有意に緩和し得る外形形状を取り得るため好ましい。具体的には、ドメインの断面積に対する該ドメインが含む該導電性粒子の断面積の割合が、20%以上であることが好ましい。
 ドメインの周面の凹凸がない形状に関しては、下記式(9)を満たすことが好ましいことを本発明者らは見出した。
 1.00≦A/B≦1.10        (9)
(A:ドメインの周囲長、B:ドメインの包絡周囲長)
 式(9)は、ドメインの周囲長Aと、ドメインの包絡周囲長Bとの比を示している。ここで、包絡周囲長とは、図7に示されるように、観察領域で観察されるドメイン71の凸包絡73の長さである。なお、凸包絡とは、ドメイン71内のすべての点を含む最小の凸集合である。
 ドメインの周囲長と、ドメインの包絡周囲長との比は1が最小値であり、1である状態は、ドメインが真円或いは楕円等の断面形状に凹部がない形状であることを示す。これらの比が1.1を超えると、ドメインに大きな凸凹形状が存在することとなり、すなわち、電界の異方性が発現する。
 要件(B2)で規定したように、ドメイン中に導電性粒子を高密度に充填することで、ドメインの外形形状を球体に近づけることができると共に、前記要件(B3)に規定したように凹凸が小さいものとすることができる。
 要件(B2)で規定したような、導電性粒子が高密度に充填されたドメインを得るために、導電性粒子として、DBP吸収量が40cm/100g以上、80cm/100g以下であるカーボンブラックを特に好適に用い得る。DBP吸収量(cm/100g)とは、100gのカーボンブラックが吸着し得るジブチルフタレート(DBP)の体積であり、日本工業規格(JIS) K 6217-4:2017(ゴム用カーボンブラック-基本特性-第4部:オイル吸収量の求め方(圧縮試料を含む))に従って測定される。一般に、カーボンブラックは、平均粒径10nm以上、50nm以下の一次粒子がアグリゲートした房状の高次構造を有している。この房状の高次構造はストラクチャーと呼ばれ、その程度はDBP吸収量(cm/100g)で定量化される。
 一般的に、ストラクチャーが発達したカーボンブラックは、ゴムに対し補強性が高く、ゴムへのカーボンブラックの取り込みが悪くなり、また、混練時のシェアトルクが非常に高くなる。そのため、ドメイン中に充填量を多くすることが困難である。
 一方、DBP吸収量が上記範囲内にある導電性カーボンブラックは、ストラクチャー構造が未発達のため、カーボンブラックの凝集が少なく、ゴムへの分散性が良好である。そのため、ドメイン中への充填量を多くでき、その結果として、ドメインの外形形状を、より球体に近いものを得られやすい。
 さらに、ストラクチャーが発達したカーボンブラックは、カーボンブラック同士が凝集し易く、また、凝集体は、大きな凸凹構造を有する塊となりやすい。このような凝集体がドメインに含まれると、要件(B3)に係るドメインが得られにくい。形状にまで影響を与え凹凸構造を形成する場合がある。一方、DBP吸収量が、上記した範囲内にある導電性カーボンブラックは、凝集体を形成し難いため、要件(B3)に係るドメインを作成するうえで有効である。
Further, in order to suppress resistance variation and electric field concentration due to aggregation of the conductive agent and to achieve the effect of the present invention more efficiently, the conductive layer has a length of the conductive layer when the length in the longitudinal direction of the conductive layer is L. The depth from the outer surface of the elastic layer is 0.1T to 0.9T for each of the cross sections in the thickness direction of the conductive layer at the center in the direction and at three points L / 4 from both ends of the conductive layer toward the center. When an observation area of 15 μm square is placed at any three locations in the thickness area up to 80% or more of the domains observed in each of the nine observation areas, the following requirement (B2) It is preferable to satisfy the requirement (B3).
Requirement (B2)
The ratio of the cross-sectional area of the conductive particles included in the domain to the cross-sectional area of the domain is 20% or more. Requirement (B3)
When the perimeter of the domain is A and the envelope perimeter of the domain is B, A / B is 1.00 or more and 1.10 or less.
The requirement (B2) and the requirement (B3) can be said to be regulations relating to the shape of the domain. The “domain shape” is defined as a cross-sectional shape of a domain that appears in a cross-section in the thickness direction of the conductive layer. In the case of a cylindrical charging member, when the length in the longitudinal direction of the conductive layer is L and the thickness of the conductive layer is T, the length in the longitudinal direction of the conductive layer and from both ends of the conductive layer toward the center is L. A cross section in the thickness direction of the conductive layer as shown in FIG. For each of the obtained cross-sections, 15 μm square observation regions are placed at any three locations in the thickness region from the outer surface of the conductive layer to the depth of 0.1T to 0.9T in the direction of the support. The domain shape is defined by the shape of each domain observed in each of the nine observation regions.
The shape of the domain is preferably a shape having no irregularities on its peripheral surface. By reducing the number of concavo-convex structures related to the shape, it is possible to reduce the non-uniformity of the electric field between domains, that is, to reduce the number of locations where electric field concentration occurs and to reduce the phenomenon of unnecessary charge transport in the matrix. The present inventor has found that the amount of conductive particles contained in one domain has an influence on the outer shape of the domain.
That is, it was found that the outer shape of the domain becomes closer to a sphere as the filling amount of the conductive particles of one domain increases. As the number of domains close to a sphere increases, the concentration point of electron transfer between domains can be reduced. And, according to the study by the present inventors, the reason is not clear, but the ratio of the sum of the cross-sectional areas of the conductive particles observed in the cross section is 20% or more based on the area of the cross section of one domain. The domain that is can take a shape closer to a sphere. As a result, it is preferable because an outer shape capable of significantly relaxing the concentration of electron transfer between domains can be obtained. Specifically, the ratio of the cross-sectional area of the conductive particles included in the domain to the cross-sectional area of the domain is preferably 20% or more.
The present inventors have found that it is preferable to satisfy the following formula (9) for a shape having no irregularities on the peripheral surface of the domain.
1.00 ≦ A / B ≦ 1.10 (9)
(A: Domain perimeter, B: Domain envelope perimeter)
Equation (9) shows the ratio of the perimeter length A of the domain to the envelope perimeter length B of the domain. Here, the envelope perimeter is the length of the convex envelope 73 of the domain 71 observed in the observation region, as shown in FIG. The convex envelope is a minimum convex set including all points in the domain 71.
The ratio of the perimeter of the domain to the envelope perimeter of the domain has a minimum value of 1, and a state of 1 indicates that the domain has a cross-sectional shape such as a perfect circle or an ellipse with no recess. When these ratios exceed 1.1, a large uneven shape exists in the domain, that is, an electric field anisotropy is developed.
As defined in the requirement (B2), by filling the domain with conductive particles at a high density, the outer shape of the domain can be made close to a sphere, and the irregularities as defined in the requirement (B3) can be obtained. It can be small.
As defined in requirement (B2), for the conductive particles to obtain a domain that is densely packed, as the conductive particles, DBP absorption amount of 40 cm 3/100 g or more, the carbon black is not more than 80 cm 3/100 g Can be used particularly preferably. The DBP absorption (cm 3 / 100g), the volume of dibutyl phthalate carbon black 100g can adsorb (DBP), Japanese Industrial Standards (JIS) K 6217-4: 2017 (the carbon black for rubber - basic characteristics -Part 4: Measured according to how oil absorption is determined (including compressed samples). Generally, carbon black has a tufted higher order structure in which primary particles having an average particle diameter of 10 nm or more and 50 nm or less are aggregated. The tufted conformation called structure, the degree is quantified by DBP absorption (cm 3 / 100g).
In general, a carbon black having a developed structure has a high reinforcing property against rubber, and the incorporation of carbon black into the rubber becomes poor, and the shear torque at the time of kneading becomes very high. Therefore, it is difficult to increase the filling amount in the domain.
On the other hand, conductive carbon black having DBP absorption in the above range has less developed structure, and therefore has less carbon black aggregation and good dispersibility in rubber. Therefore, the amount of filling into the domain can be increased, and as a result, the outer shape of the domain can be easily obtained closer to a sphere.
In addition, carbon black having a developed structure tends to aggregate together, and the aggregate tends to be a lump having a large uneven structure. When such an aggregate is contained in the domain, it is difficult to obtain the domain according to the requirement (B3). The shape may be affected to form a concavo-convex structure. On the other hand, conductive carbon black having a DBP absorption in the above-described range is effective in forming the domain according to the requirement (B3) because it is difficult to form an aggregate.
<ドメインの形状に関する各パラメーターの測定方法>
 まず、前述のマトリックスの体積抵抗率の測定における方法と同様の方法で切片を作製する。ただし、下記のように、導電性部材の長手方向に対して垂直な断面によって、切片を作成し、当該切片の破断面におけるドメインの形状を評価する必要がある。この理由を下記に述べる。
 図8Aおよび図8Bでは、現像部材81を、3軸、具体的にはX、Y、Z軸の3次元としてその形状を示した図を示す。図8Aおよび図8BにおいてX軸は現像部材の長手方向(軸方向)と平行な方向、Y軸、Z軸は現像部材の軸方向と垂直な方向を示す。
 図8Aは、現像部材に対して、XZ平面82と平行な断面82aで現像部材を切り出すイメージ図を示す。XZ平面は現像部材の軸を中心として、360°回転することができる。現像部材が、その該表面においてトナーと接触した状態で回転し、トナーに電荷供給することを考慮すると、当該XZ平面82と平行な断面82aは、あるタイミングに同時に電荷供給が起きる面を示していることになる。一定量の断面82aに相当する面が通過することによって、トナーへの電荷供給が行われる。
 したがって、現像部材内の電界集中と相関する、ドメインの形状の評価のためには、断面82aのようなある一瞬において同時に電荷供給が発生する断面の解析ではなく、一定量の断面82aを含むドメイン形状の評価ができる現像部材の軸方向と垂直なYZ平面83と平行な断面での評価が必要である。この評価に、該導電層の長手方向の長さをLとしたとき、導電層の長手方向の中央での断面83bと、および該導電層の両端から中央に向かってL/4の2か所の断面(83aおよび83c)の計3か所を選択する。
 また、当該断面83a~83cの観察位置に関しては、導電層の厚さをTとしたとき、各切片のそれぞれ外表面から深さ0.1T以上、0.9T以下までの厚み領域の任意の3か所で15μm四方の観察領域を置いたときの、合計9か所の観察領域で測定を行えばよい。
 破断面の形成は、凍結割断法、クロスポリッシャー法、収束イオンビーム法(FIB)等の手段で破断面を形成することができる。破断面の平滑性と、観察のための前処理を考慮すると、FIB法が好ましい。また、マトリックスドメイン構造の観察を好適に実施するために、染色処理、蒸着処理など、導電相と絶縁相とのコントラストが好適に得られる前処理を施してもよい。
 破断面の形成、前処理を行った切片に対して、走査型電子顕微鏡(SEM)や透過型電子顕微鏡(TEM)によってマトリックスドメイン構造を観察することができる。これらの中でも、ドメインの面積の定量化の正確性から、SEMで1000倍~100000倍で観察を行うことが好ましい。
 ドメインの周囲長、包絡周囲長、およびドメイン個数の測定は、上記で撮影画像を定量化することによって行なうことができる。SEMでの観察により得られた破断面画像に対し、ImageProPlus(Media Cybernetics社製)のような画像処理を使用して、それぞれの観察位置で得られる9枚の画像から、それぞれ15μm四方の解析領域抽出し、8ビットのグレースケール化を行い、256諧調のモノクロ画像を得る。次いで、破断面内のドメインが白くなるように、画像の白黒を反転処理し、2値化して解析用の2値化画像を得ることができる。
<Measurement method of each parameter related to domain shape>
First, a slice is prepared by the same method as that used in the measurement of the volume resistivity of the matrix. However, as described below, it is necessary to create a section with a cross section perpendicular to the longitudinal direction of the conductive member, and to evaluate the shape of the domain in the fracture surface of the section. The reason is described below.
8A and 8B are diagrams showing the shape of the developing member 81 as three axes, specifically, the three dimensions of the X, Y, and Z axes. 8A and 8B, the X axis indicates a direction parallel to the longitudinal direction (axial direction) of the developing member, and the Y axis and the Z axis indicate directions perpendicular to the axial direction of the developing member.
FIG. 8A shows an image diagram of cutting out the developing member at a cross section 82a parallel to the XZ plane 82 with respect to the developing member. The XZ plane can be rotated 360 ° about the axis of the developing member. Considering that the developing member rotates in contact with the toner on its surface and supplies charge to the toner, a cross section 82a parallel to the XZ plane 82 shows a surface where charge supply occurs simultaneously at a certain timing. Will be. When a surface corresponding to a certain amount of the cross section 82a passes, charge is supplied to the toner.
Therefore, in order to evaluate the shape of the domain, which correlates with the electric field concentration in the developing member, it is not an analysis of a cross section where charge supply is generated simultaneously in a certain moment like the cross section 82a, but a domain including a certain amount of the cross section 82a. It is necessary to evaluate the cross section parallel to the YZ plane 83 perpendicular to the axial direction of the developing member capable of evaluating the shape. In this evaluation, when the length in the longitudinal direction of the conductive layer is L, the cross-section 83b at the center in the longitudinal direction of the conductive layer, and two locations of L / 4 from both ends of the conductive layer toward the center A total of three sections (83a and 83c) are selected.
Further, regarding the observation position of the cross sections 83a to 83c, when the thickness of the conductive layer is T, any three thickness regions from the outer surface of each section to a depth of 0.1 T or more and 0.9 T or less are used. The measurement may be performed in a total of nine observation regions when 15 μm square observation regions are placed at various locations.
The fracture surface can be formed by means such as a freezing cleaving method, a cross polisher method, or a focused ion beam method (FIB). The FIB method is preferable in consideration of the smoothness of the fracture surface and pretreatment for observation. Further, in order to preferably observe the matrix domain structure, a pretreatment such as a dyeing treatment or a vapor deposition treatment that can suitably obtain the contrast between the conductive phase and the insulating phase may be performed.
The matrix domain structure can be observed with a scanning electron microscope (SEM) or a transmission electron microscope (TEM) with respect to a section subjected to formation of a fracture surface and pretreatment. Among these, from the accuracy of quantification of the area of the domain, it is preferable to observe with a SEM at 1000 to 100,000 times.
Measurement of the perimeter of the domain, the perimeter of the envelope, and the number of domains can be performed by quantifying the captured image as described above. Using the image processing such as ImageProPlus (manufactured by Media Cybernetics) on the fracture surface image obtained by observation with SEM, from the nine images obtained at each observation position, each 15 μm square analysis area Extraction and 8-bit gray scale are performed to obtain a 256-tone monochrome image. Next, the black and white of the image is inverted so that the domain in the fracture surface becomes white, and binarized to obtain a binarized image for analysis.
<<ドメイン内の電子導電剤の断面積割合μの測定方法>>
 ドメイン内の電子導電剤の断面積割合の測定は、上記の2値化画像を定量化することによって行なうことができる。2値化画像に対し、画像処理ソフトImageProPlus(Media Cybernetics社製)内のカウント機能により、ドメインの断面積Sおよび、それぞれのドメイン内の導電剤からなる部分の断面積の総和Scを算出する。そして、Sc/Sの算術平均値μ(%)を算出すればよい。
 円柱状の現像部材の場合では、導電層の長手方向の長さをL、導電層の厚さをTとしたとき、導電層の長手方向の中央、および導電層の両端から中央に向かってL/4の3か所における、図8Bに示されるような導電層の厚さ方向の断面を取得する。得られた断面の各々について、導電層の外表面から支持体方向への深さ0.1T~0.9Tまでの厚み領域の任意の3か所の15μm四方の領域において、上記の測定を行い、合計9点の領域からの測定値の算術平均から算出すればよい。
<< Method for measuring cross-sectional area ratio μ of electronic conductive agent in domain >>
The ratio of the cross-sectional area of the electronic conductive agent in the domain can be measured by quantifying the binarized image. For the binarized image, the cross-sectional area S of the domain and the sum of the cross-sectional areas of the portions made of the conductive agent in each domain are calculated by the counting function in the image processing software ImageProPlus (Media Cybernetics). Then, the arithmetic average value μ (%) of Sc / S may be calculated.
In the case of a cylindrical developing member, when the length of the conductive layer in the longitudinal direction is L and the thickness of the conductive layer is T, the length in the longitudinal direction of the conductive layer and the distance from both ends of the conductive layer toward the center are L. A cross section in the thickness direction of the conductive layer as shown in FIG. For each of the obtained cross-sections, the above measurement was performed at any three 15 μm square regions in the thickness region from the outer surface of the conductive layer to the depth of 0.1T to 0.9T in the direction of the support. It may be calculated from the arithmetic average of the measured values from a total of nine points.
<<ドメインの周囲長A、包絡周囲長Bの測定方法>>
 ドメインの周囲長、包絡周囲長、およびドメイン個数の測定は、上記の2値化画像を定量することで行うことができる。2値化画像に対し、画像処理ソフトImageProPlus(Media Cybernetics社製)のカウント機能を用いて、画像内のドメインサイズ群のそれぞれのドメインの周囲長A、ドメインの包絡周囲長B、を算出し、ドメインの周囲長比A/Bの算術平均値を算出すればよい。
 円柱状の現像部材の場合では、導電層の長手方向の長さをL、導電層の厚さをTとしたとき、導電層の長手方向の中央、および導電層の両端から中央に向かってL/4の3か所における、図8Bに示されるような導電層の厚さ方向の断面を取得する。得られた断面の各々について、導電層の外表面から支持体方向への深さ0.1T~0.9Tまでの厚み領域の任意の3か所の15μm四方の領域において、上記の測定を行い、合計9点の領域からの測定値の算術平均から算出すればよい。
<< Measurement Method of Domain Perimeter A and Envelope Perimeter B >>
The measurement of the perimeter of the domain, the perimeter of the envelope, and the number of domains can be performed by quantifying the binary image. For the binarized image, using the count function of the image processing software ImageProPlus (Media Cybernetics), calculate the perimeter length A of each domain in the domain size group in the image, the envelope perimeter length B of the domain, What is necessary is just to calculate the arithmetic mean value of perimeter length ratio A / B of a domain.
In the case of a cylindrical developing member, when the length of the conductive layer in the longitudinal direction is L and the thickness of the conductive layer is T, the length in the longitudinal direction of the conductive layer and the distance from both ends of the conductive layer toward the center are L. A cross section in the thickness direction of the conductive layer as shown in FIG. For each of the obtained cross-sections, the above measurement was performed at any three 15 μm square regions in the thickness region from the outer surface of the conductive layer to the depth of 0.1T to 0.9T in the direction of the support. It may be calculated from the arithmetic average of the measured values from a total of nine points.
<ドメインサイズ>
 本態様に係るドメインは、先に挙げた構成(iv)および構成(v)を満たしているドメインの各々に含まれるドメインの最大フェレ径(以降、単に「ドメイン径」ともいう)Lの平均を0.1μm以上、5.0μm以下とすることが好ましい。
 ドメイン径ドメイン径Lの平均値を、0.1μm以上とすることで、導電層において、電荷の移動する経路を目的とする経路により効果的に限定することができる。また、ドメイン径Lの平均値を5.0μm以下にすることで、ドメインの全体積に対する表面積の割合、すなわち、比表面積を指数関数的に大きくすることができ、ドメインからの電荷の放出効率を飛躍的に向上させ得る。ドメイン径Lの平均値は、上記の理由から、2.0μm以下、さらには、1.0μm以下とすることが好ましい。
 なお、ドメイン間での電界集中のより一層の軽減を図る上では、ドメインの外形形状をより球体に近づけることが好ましい。そのためには、ドメイン径を、前記した範囲内でより小さくすることが好ましい。その方法としては、例えば、工程(iv)において、MRCとCMBとを混練して、MRCとCMBとを相分離させて、MRCのマトリックス中にCMBのドメインを形成されたゴム混合物を調製する工程において、CMBのドメイン径を小さくするように制御する方法が挙げられる。CMBのドメイン径を小さくすることでCMBの比表面積が増大し、マトリックスとの界面が増加するため、CMBのドメインの界面には張力を小さくしようとする張力が作用する。その結果、CMBのドメインは、その外形形状が、より球体に近づく。
<Domain size>
The domain according to this aspect is the average of the maximum Feret diameter (hereinafter also simply referred to as “domain diameter”) L of domains included in each of the domains satisfying the configuration (iv) and the configuration (v) listed above. The thickness is preferably 0.1 μm or more and 5.0 μm or less.
By setting the average value of the domain diameter L and the domain diameter L to be 0.1 μm or more, in the conductive layer, the path through which charges move can be effectively limited by the intended path. In addition, by setting the average value of the domain diameter L to 5.0 μm or less, the ratio of the surface area to the total volume of the domain, that is, the specific surface area can be increased exponentially, and the charge emission efficiency from the domain can be increased. It can be improved dramatically. The average value of the domain diameter L is preferably 2.0 μm or less, and more preferably 1.0 μm or less for the above reason.
In order to further reduce the electric field concentration between the domains, it is preferable to make the outer shape of the domain closer to a sphere. For that purpose, it is preferable to make the domain diameter smaller within the above-mentioned range. As the method, for example, in step (iv), MRC and CMB are kneaded, and MRC and CMB are phase separated to prepare a rubber mixture in which CMB domains are formed in the matrix of MRC. And a method of controlling the CMB domain diameter to be small. By reducing the domain diameter of the CMB, the specific surface area of the CMB is increased and the interface with the matrix is increased. Therefore, a tension for reducing the tension acts on the interface of the CMB domain. As a result, the outer shape of the CMB domain is closer to a sphere.
 前記構成(iii)に関連して、ドメイン間距離の均一化を図るためには、前記Taylorの式(式(5))、Wuの経験式(式(6)、(7))、およびTokitaの式(式(8))に従って、ドメインサンズを小さくすることが有効である。さらに、マトリックスドメイン構造が混錬工程において、ドメインの原料ゴムが***し、徐々にその粒系が小さくなっていく過程において、混錬工程をどこで止めたかによっても支配される。したがって、そのドメイン間距離の均一性は、混錬過程における混錬時間およびその混錬の強度の指数となる混錬回転数によって制御可能であり、混錬時間が長いほど、混錬回転数が大きいほどドメイン間距離の均一性を向上させることができる。 In relation to the configuration (iii), the Taylor equation (Equation (5)), Wu's empirical equations (Equations (6) and (7)), and Tokita It is effective to reduce the domain sands according to the equation (Equation (8)). Furthermore, the matrix domain structure is governed by where the kneading process is stopped in the process where the raw material rubber of the domain is split in the kneading process and the grain system gradually becomes smaller. Therefore, the uniformity of the distance between the domains can be controlled by the kneading time in the kneading process and the kneading speed that is an index of the strength of the kneading. As the size increases, the uniformity of the distance between domains can be improved.
・ドメインサイズの均一性;
 ドメインサイズは均一であるほど、つまり、粒度分布が狭い方が好ましい。導電層内の電荷が通るドメインのサイズの分布を均一とすることで、マトリックスドメイン構造内での電荷の集中を抑制し、現像部材の全面にわたって電荷の出やすさを効果的に増大することができる。電荷が輸送される断面、すなわち、導電層の厚さ方向の断面において、導電層の外表面から支持体方向への深さ0.1T~0.9Tまでの厚み領域の任意の3か所における、50μm四方の観察領域を取得した際に、ドメインサイズの標準偏差σdおよびドメインサイズの平均値Dの比σd/Dが0以上、0.4以下であることが好ましい。
・ Uniformity of domain size;
The more uniform the domain size, that is, the narrower the particle size distribution is. By making the distribution of the size of the domain through which the electric charge passes in the conductive layer uniform, the concentration of the electric charge in the matrix domain structure can be suppressed, and the easiness of the electric charge can be effectively increased over the entire surface of the developing member. it can. In the cross section where the charge is transported, that is, in the cross section in the thickness direction of the conductive layer, at any three locations in the thickness region from the outer surface of the conductive layer to the depth of 0.1T to 0.9T in the direction of the support When the observation area of 50 μm square is acquired, the ratio σd / D of the standard deviation σd of the domain size and the average value D of the domain size is preferably 0 or more and 0.4 or less.
 ドメインサイズの均一性を向上させるためには、前述のドメイン間距離の均一性を向上させる手法と等しく、式(5)~式(8)に従い、ドメインサイズを小さくすればドメインサイズの均一性も向上する。さらに、マトリックスドメイン構造が混錬工程において、ドメインの原料ゴムが***し、徐々にその粒系が小さくなっていく過程において、混錬工程をどこで止めたかによっても支配される。したがって、そのドメインサイズの均一性は、混錬過程における混錬時間およびその混錬の強度の指数となる混錬回転数によって制御可能であり、混錬時間が長いほど、混錬回転数が大きいほどドメインサイズの均一性を向上させることができる。 In order to improve the uniformity of the domain size, it is equivalent to the above-described method of improving the uniformity of the inter-domain distance. If the domain size is reduced according to the equations (5) to (8), the uniformity of the domain size is also improved. improves. Furthermore, the matrix domain structure is governed by where the kneading process is stopped in the process where the raw material rubber of the domain is split in the kneading process and the grain system gradually becomes smaller. Therefore, the uniformity of the domain size can be controlled by the kneading time in the kneading process and the kneading speed which is an index of the strength of the kneading. The longer the kneading time, the larger the kneading speed. The uniformity of domain size can be improved.
<マトリックスドメイン構造の確認方法>
 導電層中のマトリックスドメイン構造の存在は、導電層から薄片を作製して、薄片に形成した破断面の詳細観察により確認することができる。
 薄片化する手段としては、例えば、鋭利なカミソリや、ミクロトーム、FIBなどがあげられる。また、マトリックスドメイン構造のより正確な観察を実施するために、染色処理、蒸着処理など、導電相としてのドメインと絶縁相としてのマトリックスとのコントラストが好適に得られる前処理を観察用の薄片に施してもよい。
 破断面の形成、および必要に応じて前処理を行った薄片に対して、レーザー顕微鏡、走査型電子顕微鏡(SEM)や透過型電子顕微鏡(TEM)によって破断面を観察してマトリックスドメイン構造の存在を確認することができる。簡易的、かつ正確に海島構造を確認できる手法として、走査型電子顕微鏡(SEM)で観察することが好ましい。
 上記のような手法で導電層の薄片を取得し、当該薄片の表面を1000倍~10000倍で観察して得られる画像を取得した後、「ImageProPlus」(商品名、Media Cybernetics社製)の如き画像処理ソフトウェアを使用して、8ビットのグレースケール化を行い、256諧調のモノクロ画像を得る。次いで、破断面内のドメインが白くなるように、画像の白黒を反転処理し、2値化をして解析画像を取得する。ドメインおよびマトリックスを2値化によって区別する状態に画像処理した当該解析画像によって、マトリックスドメイン構造の有無を判断すればよい。
 当該解析画像に、図6のように、複数のドメインがマトリックス中に孤立した状態で存在する構造が含まれている場合に、導電層中でのマトリックスドメイン構造の存在を確認することができる。ドメインの孤立状態は、各ドメインが他のドメインと連結していない状態で配置され、かつ、マトリックスは画像内で連通し、ドメインがマトリックスによって分断されている状態であればよい。具体的には、当該解析画像内の50μm四方内を解析領域としたとき、当該解析領域の枠線と接点を持たないドメイン群の総数に対して、上記のように孤立状態で存在するドメインの個数が、80個数パーセント以上存在する状態を、海島構造を有する状態とする。
 上記のような確認を、現像部材の導電層を長手方向に均等に5等分し、周方向に均等に4等分し、それぞれの領域から任意に1点ずつ、合計20点から当該切片を作製して上記測定を行えばよい。
<Method for confirming the matrix domain structure>
Presence of the matrix domain structure in the conductive layer can be confirmed by preparing a thin piece from the conductive layer and observing the fractured surface formed in the thin piece in detail.
Examples of the thinning means include a sharp razor, a microtome, and an FIB. In addition, in order to carry out more accurate observation of the matrix domain structure, pre-treatments such as dyeing treatment and vapor deposition treatment that can obtain a suitable contrast between the domain as the conductive phase and the matrix as the insulating phase are applied to the observation flakes. You may give it.
Existence of matrix domain structure by observing the fracture surface with a laser microscope, scanning electron microscope (SEM) or transmission electron microscope (TEM) on the fractured surface, and pre-treated thin pieces as necessary Can be confirmed. As a method for simply and accurately confirming the sea-island structure, it is preferable to observe with a scanning electron microscope (SEM).
After obtaining a slice of the conductive layer by the above-described method and obtaining an image obtained by observing the surface of the slice at a magnification of 1000 to 10000 times, such as “ImageProPlus” (trade name, manufactured by Media Cybernetics) Using image processing software, 8-bit gray scale is performed to obtain a 256-tone monochrome image. Next, the black and white of the image is inverted so that the domain in the fracture surface becomes white, and binarization is performed to obtain an analysis image. The presence / absence of the matrix domain structure may be determined based on the analysis image obtained by performing image processing so that the domain and the matrix are distinguished by binarization.
When the analysis image includes a structure in which a plurality of domains exist in an isolated state in the matrix as shown in FIG. 6, the presence of the matrix domain structure in the conductive layer can be confirmed. The domain isolation state may be a state in which each domain is arranged in a state where it is not connected to another domain, and the matrix communicates in the image, and the domain is divided by the matrix. Specifically, when the analysis area is in the 50 μm square in the analysis image, the total number of domains that do not have a contact with the border of the analysis area is the number of domains that exist in an isolated state as described above. A state where the number is 80 percent or more is defined as a state having a sea-island structure.
The above confirmation is made by equally dividing the conductive layer of the developing member into 5 equal parts in the longitudinal direction, equally dividing into 4 parts in the circumferential direction, and arbitrarily dividing each section from 20 points in total from each region. The above measurement may be performed.
 現像部材は必要に応じて適正な表面粗さを有する場合がある。現像部材が現像ローラまたは現像スリーブである場合、表面粗さは十点平均粗さ(Rz)で2.0μm~8.0μmの範囲にあることが好ましく、2.0μm~4.5μmの範囲にあることが特に好ましい。
 現像部材が現像ブレードの場合は、表面粗さは十点平均粗さ(Rz)で0.0μm~6.0μmの範囲にあることが好ましく、0.0μm~1.5μmの範囲にあることが特に好ましい。
 表面粗さがこの範囲にあると、トナーとの均一な接触と、適正なトナー搬送量が両立され、トナーへの電荷供給を均一にしやすくすることができる。
 現像部材の表面粗さの形成方法としては、研磨、型転写、レーザー処理が挙げられる。
 現像部材がローラ形状である場合は、導電層の成形方法としては、液状ゴム材料を型成形する方法や、混練ゴム材料を押出し成形する方法が挙げられる。
 また、現像部材がブレード形状である場合は、その成形方法として、型成形、射出成形、押出し成形、遠心成形する方法が挙げられる。
The developing member may have an appropriate surface roughness as required. When the developing member is a developing roller or a developing sleeve, the surface roughness is preferably in the range of 2.0 μm to 8.0 μm in terms of 10-point average roughness (Rz), and in the range of 2.0 μm to 4.5 μm. It is particularly preferred.
When the developing member is a developing blade, the surface roughness is preferably in the range of 0.0 μm to 6.0 μm in terms of ten-point average roughness (Rz), and preferably in the range of 0.0 μm to 1.5 μm. Particularly preferred.
When the surface roughness is within this range, uniform contact with the toner and an appropriate amount of toner conveyance are compatible, and the charge supply to the toner can be easily made uniform.
Examples of the method for forming the surface roughness of the developing member include polishing, mold transfer, and laser treatment.
When the developing member has a roller shape, examples of the method for forming the conductive layer include a method of molding a liquid rubber material and a method of extruding a kneaded rubber material.
When the developing member has a blade shape, examples of the molding method include mold molding, injection molding, extrusion molding, and centrifugal molding.
(2)電子写真装置
 本発明に係る現像部材は、電子写真用画像形成装置としての電子写真装置における現像ローラ、トナー供給ローラ、現像スリーブ、および現像ブレードとして好適に用いることができる。現像部材は、磁性一成分トナーや非磁性一成分トナーを用いた非接触型現像装置および接触型現像装置、ならびに二成分トナーを用いた現像装置のいずれの現像装置にも適用することができる。
 図10は、本発明に係る現像部材を、一成分トナーを用いた接触型現像装置の現像ローラとして搭載した電子写真装置の一例を示す概略断面図である。現像装置22は、一成分トナーとしてトナー15を収容したトナー容器20と、現像ローラ16と、現像ローラ16へトナーを供給するトナー供給ローラ19と、現像ローラ16上のトナー層の厚さを規制する現像ブレード21とを含む。現像ローラ16は、トナー容器20内の長手方向に延在する開口部に位置し、感光体18に対して接触設置されている。なお、感光体18、クリーニングブレード26、廃トナー収容容器25、帯電ローラ24は、電子写真装置本体に配備されていてもよい。現像装置22は、ブラック(Bk)、シアン(C)、マゼンタ(M)、イエロー(Y)の各色トナーに用意されており、カラー印刷を可能としている。
 以下、電子写真装置のプリント動作を説明する。感光体18は矢印方向に回転し、感光体18を帯電処理するための帯電ローラ24によって一様に帯電される。次いで、露光手段であるレーザー光23により、感光体18の表面に静電潜像が形成される。該静電潜像は、現像装置22によって、感光体18に対して接触配置される現像ローラ16からトナー15が付与されることにより、トナー像として可視化される(現像)。現像は露光部にトナー像を形成する、いわゆる反転現像である。
 感光体18上に形成されたトナー像は、転写部材である転写ローラ29によってエンドレスベルト状の中間転写体32に転写される。
 記録媒体である紙34は、給紙ローラ35および二次転写ローラ36により装置内に給紙され、トナー画像を有する中間転写体32と共に、二次転写ローラ36と従動ローラ33とにニップ部に搬送され、紙34にトナー画像が転写される。中間転写体32は、従動ローラ33、駆動ローラ39、テンションローラ38により稼働している。中間転写体32上に残るトナーはクリーニング装置37によりクリーニングされる。
 現像ローラ16、現像ブレード21、転写ローラ29および二次転写ローラ36には、バイアス電源30から電圧が印加されている。トナー像が転写された紙34は、定着装置27により定着処理され、装置外に排紙されて、プリント動作が終了する。一方、転写されずに感光体18上に残存した転写残トナーは、感光体表面をクリーニングするためのクリーニング部材であるクリーニングブレード26により掻き取られ、廃トナー収容容器25に収納される。クリーニングされた感光体18は、以上のプリント動作を繰り返し行う。
(2) Electrophotographic apparatus The developing member according to the present invention can be suitably used as a developing roller, a toner supply roller, a developing sleeve, and a developing blade in an electrophotographic apparatus as an electrophotographic image forming apparatus. The developing member can be applied to any developing device such as a non-contact developing device and a contact developing device using magnetic one-component toner or non-magnetic one-component toner, and a developing device using two-component toner.
FIG. 10 is a schematic cross-sectional view showing an example of an electrophotographic apparatus in which the developing member according to the present invention is mounted as a developing roller of a contact-type developing device using a one-component toner. The developing device 22 regulates the thickness of the toner container 20 containing the toner 15 as a one-component toner, the developing roller 16, the toner supply roller 19 that supplies toner to the developing roller 16, and the toner layer on the developing roller 16. Developing blade 21. The developing roller 16 is located in an opening extending in the longitudinal direction in the toner container 20 and is placed in contact with the photoreceptor 18. Note that the photoconductor 18, the cleaning blade 26, the waste toner container 25, and the charging roller 24 may be provided in the main body of the electrophotographic apparatus. The developing device 22 is prepared for each color toner of black (Bk), cyan (C), magenta (M), and yellow (Y), and enables color printing.
Hereinafter, the printing operation of the electrophotographic apparatus will be described. The photoconductor 18 rotates in the direction of the arrow and is uniformly charged by a charging roller 24 for charging the photoconductor 18. Next, an electrostatic latent image is formed on the surface of the photoreceptor 18 by the laser beam 23 that is an exposure means. The electrostatic latent image is visualized as a toner image (development) by applying the toner 15 from the developing roller 16 disposed in contact with the photoreceptor 18 by the developing device 22. Development is so-called reversal development in which a toner image is formed in the exposed portion.
The toner image formed on the photosensitive member 18 is transferred to an endless belt-like intermediate transfer member 32 by a transfer roller 29 as a transfer member.
A paper 34 as a recording medium is fed into the apparatus by a paper feed roller 35 and a secondary transfer roller 36, and, together with an intermediate transfer body 32 having a toner image, is placed at a nip portion between the secondary transfer roller 36 and the driven roller 33. The toner image is transferred to the paper 34 by being conveyed. The intermediate transfer member 32 is operated by a driven roller 33, a driving roller 39, and a tension roller 38. The toner remaining on the intermediate transfer member 32 is cleaned by the cleaning device 37.
A voltage is applied from the bias power supply 30 to the developing roller 16, the developing blade 21, the transfer roller 29, and the secondary transfer roller 36. The paper 34 to which the toner image has been transferred is subjected to fixing processing by the fixing device 27 and discharged outside the device, and the printing operation is completed. On the other hand, the untransferred toner remaining on the photoconductor 18 without being transferred is scraped off by a cleaning blade 26 which is a cleaning member for cleaning the surface of the photoconductor and stored in a waste toner container 25. The cleaned photoreceptor 18 repeats the above printing operation.
(3)プロセスカートリッジ
 上記した本態様に係る現像部材は、プロセスカートリッジにおける現像ローラ、トナー供給ローラ、現像スリーブ、および現像ブレードとして好適に用いることができる。図9は、本発明の一態様に係るプロセスカートリッジの一例の概略断面図である。図9において、上記現像部材は、現像ローラ16として搭載されている。プロセスカートリッジ17は、電子写真装置の本体に着脱可能に構成されている。プロセスカートリッジ17は、現像ローラ16と現像ブレード21とを備える現像装置22、感光体18、クリーニングブレード26、廃トナー収容容器25、および帯電ローラ24が一体化されたものである。現像装置22は、さらにトナー容器20を含み、トナー容器20内には、トナー15が充填されている。トナー容器20内のトナー15は、トナー供給ローラ19によって現像ローラ16の表面に供給され、現像ブレード21によって、現像ローラ16の表面に所定の厚みのトナー15の層が形成される。
(3) Process Cartridge The developing member according to this aspect described above can be suitably used as a developing roller, a toner supply roller, a developing sleeve, and a developing blade in a process cartridge. FIG. 9 is a schematic cross-sectional view of an example of a process cartridge according to an aspect of the present invention. In FIG. 9, the developing member is mounted as a developing roller 16. The process cartridge 17 is configured to be detachable from the main body of the electrophotographic apparatus. In the process cartridge 17, a developing device 22 including a developing roller 16 and a developing blade 21, a photoconductor 18, a cleaning blade 26, a waste toner container 25, and a charging roller 24 are integrated. The developing device 22 further includes a toner container 20, and the toner container 20 is filled with the toner 15. The toner 15 in the toner container 20 is supplied to the surface of the developing roller 16 by the toner supply roller 19, and a layer of the toner 15 having a predetermined thickness is formed on the surface of the developing roller 16 by the developing blade 21.
 以下に具体的な実施例および比較例について示す。
<現像ローラの作製>
[実施例1]
1.未加硫ドメインゴム組成物の製造
[1-1]未加硫ドメイン組成物の調製
 表1に示す量の各材料を加圧式ニーダーで混合し未加硫ドメイン組成物を得た。混合機は、6リットル加圧ニーダー(製品名:TD6-15MDX、トーシン社製)を用いた。混合条件は、充填率70vol%、ブレード回転数30rpm、16分間とした。
Specific examples and comparative examples are shown below.
<Production of developing roller>
[Example 1]
1. Production of unvulcanized domain rubber composition [1-1] Preparation of unvulcanized domain composition The materials shown in Table 1 were mixed in a pressure kneader to obtain an unvulcanized domain composition. A 6-liter pressure kneader (product name: TD6-15MDX, manufactured by Toshin Co., Ltd.) was used as the mixer. The mixing conditions were a filling rate of 70 vol%, a blade rotation speed of 30 rpm, and 16 minutes.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
[1-2]未加硫マトリックスゴム組成物の調製
 表2に示す量の各材料を加圧式ニーダーで混合し未加硫マトリックスゴム組成物を得た。混合機は、6リットル加圧ニーダー(製品名:TD6-15MDX、トーシン社製)を用いた。混合条件は、充填率70vol%、ブレード回転数30rpm、16分間とした。
[1-2] Preparation of unvulcanized matrix rubber composition The materials shown in Table 2 were mixed in a pressure kneader to obtain an unvulcanized matrix rubber composition. A 6-liter pressure kneader (product name: TD6-15MDX, manufactured by Toshin Co., Ltd.) was used as the mixer. The mixing conditions were a filling rate of 70 vol%, a blade rotation speed of 30 rpm, and 16 minutes.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
[1-3]未加硫ゴム組成物の調製
 表3に示す量の各材料を加圧式ニーダーで混合して未加硫ゴム組成物を得た。混合機は、6リットル加圧ニーダー(製品名:TD6-15MDX、トーシン社製)を用いた。混合条件は、充填率70vol%、ブレード回転数30rpm、16分間とした。
[1-3] Preparation of unvulcanized rubber composition The materials shown in Table 3 were mixed in a pressure kneader to obtain an unvulcanized rubber composition. A 6-liter pressure kneader (product name: TD6-15MDX, manufactured by Toshin Co., Ltd.) was used as the mixer. The mixing conditions were a filling rate of 70 vol%, a blade rotation speed of 30 rpm, and 16 minutes.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
[1-4]現像ローラ成形用ゴム組成物の調製
 表4に示す量の各材料をオープンロールにて混合し、現像部材成形用のゴム組成物を調製した。混合機は、ロール径12インチ(0.30m)のオープンロールを用いた。混合条件は、前ロール回転数10rpm、後ロール回転数8rpmで、ロール間隙2mmとして合計20回左右の切り返しを行った後、ロール間隙を0.5mmとして10回薄通しを行った。
[1-4] Preparation of developing roller molding rubber composition The materials shown in Table 4 were mixed in an open roll to prepare a developing member molding rubber composition. As the mixer, an open roll having a roll diameter of 12 inches (0.30 m) was used. The mixing conditions were a front roll rotation speed of 10 rpm and a rear roll rotation speed of 8 rpm, and after turning left and right a total of 20 times with a roll gap of 2 mm, thinning was performed 10 times with a roll gap of 0.5 mm.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
 2.現像ローラの成形
 支持体として、快削鋼の表面に無電解ニッケルメッキ処理を施した外径6mmの芯金を用意した。本芯金を導電性の軸芯体である支持体として使用した。
 次に、導電性支持体の供給機構、および未加硫ゴムローラの排出機構を有するクロスヘッド押出機の先端に内径16.0mmのダイスを取付け、押出機とクロスヘッドの温度を80℃に、導電性支持体の搬送速度を60mm/secに調整した。この条件で、押出機より未加硫ゴム組成物を供給して、クロスヘッド内にて導電性支持体の外周部を未加硫ゴム組成物で被覆し、未加硫ゴムローラを得た。
 次に、170℃の熱風加硫炉中に前記未加硫ゴムローラを投入し、60分間加熱することで未加硫ゴム組成物を加硫し、導電性支持体の外周部に導電性樹脂層が形成されたローラを得た。その後、導電性樹脂層の両端部を切除し、導電性樹脂層の表面を回転砥石で研磨した。これによって、中央部から両端部側へ各90mmの位置における各直径が12.0mm、中央部直径が12.2mmであるクラウン形状の現像ローラA1を得た。
2. Molding of the developing roller As a support, a core metal having an outer diameter of 6 mm was prepared by subjecting the surface of free-cutting steel to electroless nickel plating. This core metal was used as a support which is a conductive shaft core.
Next, a die having an inner diameter of 16.0 mm is attached to the tip of a crosshead extruder having a conductive support supply mechanism and an unvulcanized rubber roller discharge mechanism, and the temperature of the extruder and the crosshead is set to 80 ° C. The conveyance speed of the conductive support was adjusted to 60 mm / sec. Under these conditions, the unvulcanized rubber composition was supplied from the extruder, and the outer peripheral portion of the conductive support was coated with the unvulcanized rubber composition in the crosshead to obtain an unvulcanized rubber roller.
Next, the unvulcanized rubber roller is put into a hot air vulcanization furnace at 170 ° C. and heated for 60 minutes to vulcanize the unvulcanized rubber composition, and a conductive resin layer is formed on the outer periphery of the conductive support. A formed roller was obtained. Thereafter, both ends of the conductive resin layer were excised, and the surface of the conductive resin layer was polished with a rotating grindstone. As a result, a crown-shaped developing roller A1 having a diameter of 12.0 mm and a center diameter of 12.2 mm at positions of 90 mm from the center to both ends was obtained.
3.特性評価
[3-1]マトリックスドメイン構造の確認
 マトリックスドメイン構造が好適に形成できるかを確認するため、以下の確認を行った。
 カミソリを用いて導電層の周方向と垂直な断面が観察できるように切片を切り出した。次いで、白金蒸着を行い、走査型電子顕微鏡(SEM)(商品名:S-4800、(株)日立ハイテクノロジーズ製)を用いて1,000倍で撮影し、断面画像を得た。
 マトリックスドメイン構造は、この断面画像内において、図6のように、複数個のドメイン成分6bがマトリックス6a中に分散されて、導電パスが分断された状態であり、一方で、マトリックスは画像内で連通している状態である。
 現像ローラA1(長手方向の長さ:230mm)を長手方向に5等分し、周方向に4等分し、それぞれの領域内から任意に1点ずつ、合計20点から当該切片を作製して上記測定を行った。マトリックスドメイン構造を確認できた場合を「有」、できなかった場合は「無」と表7-1に「海島構造の有無」として示した。
[3-2]1×10Hz~1×10Hzにおける傾き、および1×10-2Hz~1×10Hzにおけるインピーダンスの測定
 インピーダンスの測定は、次のようにして行った。
 まず、前処理として、現像部材A1に対し、回転しながら真空白金蒸着をすることよって、測定電極を作成した。この時、マスキングテープを使用して、幅1.5cm、周方向に均一な電極を作成した。当該電極を形成することで、導電性部材の表面粗さによって、測定電極と導電性部材の接触面積の寄与を極力低減することができる。
 次に、当該電極に、アルミシートを隙間なく巻きつけ、当該アルミシートから、インピーダンス測定装置(商品名:ソーラトロン1260、およびソーラトロン1296;ソーラトロン社製)の測定電極に接続した。
 図11に測定電極が形成された現像ローラの概要図を示す。図11の中で、41が導電性支持体、42がマトリックスドメイン構造を有する導電層、44が白金蒸着層、43がアルミシートである。
 図12に導電性部材に測定電極が形成された現像ローラの断面図を示す。121が導電性支持体、122がマトリックスドメイン構造を有する導電層、123が白金蒸着層、124がアルミシートである。図12のように、導電性支持体と、測定電極によってマトリックスドメイン構造を有する導電層を挟む状態にすることが重要である。
 そして、当該アルミシートを、インピーダンス測定装置(商品名:ソーラトロン1260、およびソーラトロン1296;ソーラトロン社製)側の測定電極に接続した。図13に、本測定系の概要図を示す。導電性支持体と、アルミシートを測定のための2つの電極にすることで、インピーダンス測定を行なった。
 インピーダンスの測定は、温度23℃、相対湿度50%の環境において、振動電圧1Vpp、直流10V、周波数1×10-2Hz~10Hz測定(周波数が1桁変化する際に、5点ずつ測定)し、インピーダンスの絶対値を得た。次いで、測定結果をエクセル(登録商標)などの表計算ソフトを用いて、当該インピーダンスの絶対値と、角周波数(測定周波数×2×π(円周率))を両対数プロットし、1×10Hz~1×10Hzにおける傾きを算出した。
 現像ローラA1(長手方向の長さ:230mm)を長手方向に5個の領域に5等分し、それぞれの領域内から任意に1点ずつ、合計5点に測定電極を形成し、上記測定を行った。その平均値を、インピーダンスの傾きとした。
 表7-1の「傾き」と「インピーダンス」の項に導電層において得られた結果を示した。
 導電性支持体のインピーダンスを現像ローラから導電層を剥離した以外は上記と同様の方法で測定した。得られた結果を「導電性支持体」の「インピーダンス」として表7-1に示した。
[3-3]マトリックスの体積抵抗率の測定
 マトリックスの体積抵抗率は、走査型プローブ顕微鏡(SPM)(商品名:Q-Scope250、Quesant Instrument Corporation社製)を用い、コンタクトモードで測定した。
 まず、現像ローラの導電層から、ミクロトーム(商品名:Leica EM FCS、ライカマイクロシステムズ社製)を用いて、切削温度-100℃にて、2μm程度の厚みの超薄切片として切り出した。
 次に、温度23℃、相対湿度50%の環境において、当該超薄切片を金属プレート上に設置し、金属プレートに直接接触している箇所の中を選び、マトリックスに該当する箇所をSPMのカンチレバーを接触させ、次いで、カンチレバーに50Vの電圧を印加し、電流値を測定した。
 当該SPMで当該測定切片の表面形状を観察して、得られる高さプロファイルから測定箇所の厚さを算出した。さらに、表面形状観察結果から、カンチレバーの接触部の凹部面積を算出した。当該厚さと当該凹部面積とから体積抵抗率を算出し、マトリックスの体積抵抗率とした。
 現像ローラA1(長手方向の長さ:230mm)を長手方向に5等分し、周方向に4等分し、それぞれの領域内から任意に1点ずつ、合計20点から当該切片を作製して上記測定を行った。その平均値を、マトリックスの体積抵抗率とした。
 得られた結果を、「マトリックス」の「体積抵抗率」として表7-1に示した。
3. Characteristic Evaluation [3-1] Confirmation of Matrix Domain Structure In order to confirm whether the matrix domain structure can be suitably formed, the following confirmation was performed.
A slice was cut out using a razor so that a cross section perpendicular to the circumferential direction of the conductive layer could be observed. Next, platinum vapor deposition was performed, and a cross-sectional image was obtained by taking a picture at 1,000 times using a scanning electron microscope (SEM) (trade name: S-4800, manufactured by Hitachi High-Technologies Corporation).
In this cross-sectional image, the matrix domain structure is a state in which a plurality of domain components 6b are dispersed in the matrix 6a and the conductive path is divided as shown in FIG. It is in a state of communication.
The developing roller A1 (longitudinal length: 230 mm) is divided into 5 equal parts in the longitudinal direction and divided into 4 equal parts in the circumferential direction. The above measurements were made. When the matrix domain structure was confirmed, “Yes” was indicated, and when it was not possible, “No” was indicated as “Presence / absence of sea island structure” in Table 7-1.
[3-2] Measurement of slope at 1 × 10 6 Hz to 1 × 10 7 Hz and measurement of impedance at 1 × 10 −2 Hz to 1 × 10 0 Hz Impedance was measured as follows.
First, as a pretreatment, a measurement electrode was prepared by performing vacuum platinum deposition on the developing member A1 while rotating. At this time, using a masking tape, an electrode having a width of 1.5 cm and uniform in the circumferential direction was formed. By forming the electrode, the contribution of the contact area between the measurement electrode and the conductive member can be reduced as much as possible due to the surface roughness of the conductive member.
Next, an aluminum sheet was wound around the electrode without a gap, and the aluminum sheet was connected to a measurement electrode of an impedance measuring device (trade names: Solartron 1260 and Solartron 1296; manufactured by Solartron).
FIG. 11 shows a schematic diagram of a developing roller on which measurement electrodes are formed. In FIG. 11, 41 is a conductive support, 42 is a conductive layer having a matrix domain structure, 44 is a platinum deposition layer, and 43 is an aluminum sheet.
FIG. 12 shows a cross-sectional view of the developing roller in which the measurement electrode is formed on the conductive member. 121 is a conductive support, 122 is a conductive layer having a matrix domain structure, 123 is a platinum deposition layer, and 124 is an aluminum sheet. As shown in FIG. 12, it is important to sandwich a conductive layer having a matrix domain structure between a conductive support and a measurement electrode.
Then, the aluminum sheet was connected to a measurement electrode on the side of an impedance measuring device (trade name: Solartron 1260 and Solartron 1296; manufactured by Solartron). FIG. 13 shows a schematic diagram of this measurement system. Impedance measurement was performed by using a conductive support and an aluminum sheet as two electrodes for measurement.
Impedance is measured in an environment with a temperature of 23 ° C and relative humidity of 50%. Vibration voltage is 1 Vpp, DC is 10 V, frequency is 1 × 10 -2 Hz to 10 7 Hz. ) And obtained the absolute value of the impedance. Next, using a spreadsheet such as Excel (registered trademark), the absolute value of the impedance and the angular frequency (measurement frequency × 2 × π (circumference ratio)) are log-logged and the measurement result is 1 × 10. The slope from 6 Hz to 1 × 10 7 Hz was calculated.
The developing roller A1 (longitudinal length: 230 mm) is divided into five equal areas in the longitudinal direction, and measurement electrodes are formed at 5 points in total, arbitrarily from each area. went. The average value was taken as the slope of the impedance.
The results obtained for the conductive layer are shown in the “Slope” and “Impedance” sections of Table 7-1.
The impedance of the conductive support was measured by the same method as above except that the conductive layer was peeled off from the developing roller. The obtained results are shown in Table 7-1 as “impedance” of “conductive support”.
[3-3] Measurement of volume resistivity of matrix The volume resistivity of the matrix was measured in a contact mode using a scanning probe microscope (SPM) (trade name: Q-Scope250, manufactured by Questant Instrument Corporation).
First, an ultrathin slice having a thickness of about 2 μm was cut from the conductive layer of the developing roller using a microtome (trade name: Leica EM FCS, manufactured by Leica Microsystems) at a cutting temperature of −100 ° C.
Next, in an environment with a temperature of 23 ° C. and a relative humidity of 50%, the ultrathin slice is placed on a metal plate, selected from the locations that are in direct contact with the metal plate, and the location corresponding to the matrix is the SPM cantilever. Then, a voltage of 50 V was applied to the cantilever, and the current value was measured.
The surface shape of the measurement slice was observed with the SPM, and the thickness of the measurement location was calculated from the obtained height profile. Furthermore, from the surface shape observation result, the concave area of the contact portion of the cantilever was calculated. The volume resistivity was calculated from the thickness and the recess area, and was used as the volume resistivity of the matrix.
The developing roller A1 (longitudinal length: 230 mm) is divided into 5 equal parts in the longitudinal direction and 4 equal parts in the circumferential direction. The above measurements were made. The average value was taken as the volume resistivity of the matrix.
The obtained results are shown in Table 7-1 as “volume resistivity” of “matrix”.
[3-4]ドメインの体積抵抗率の測定
 ドメインの体積抵抗率は、上記マトリックスの体積抵抗率の測定において、測定箇所をドメインに該当する箇所で実施する以外は、同様の方法で行った。
 得られた結果を、「ドメイン」の「体積抵抗率」として表7-1に示した。
[3-5]マトリックスの体積抵抗率とドメインの体積抵抗率の比
 上記マトリックスの体積抵抗率R1の常用対数と、ドメインの体積抵抗率R2の常用対数を叙することで、マトリックスとドメインの体積抵抗率の比(log(R1/R2))を算出した。
 得られた結果を、「マトリックスドメイン」の「抵抗比」として表7-1に示した。
[3-4] Measurement of domain volume resistivity The volume resistivity of the domain was measured in the same manner as in the measurement of the volume resistivity of the matrix, except that the measurement location was performed at a location corresponding to the domain.
The obtained results are shown in Table 7-1 as “volume resistivity” of “domain”.
[3-5] Ratio of volume resistivity of matrix to volume resistivity of domain The volume of matrix and domain is calculated by formulating the common logarithm of volume resistivity R1 of the matrix and the common logarithm of volume resistivity R2 of the matrix. The resistivity ratio (log (R1 / R2)) was calculated.
The obtained results are shown in Table 7-1 as “resistance ratio” of “matrix domain”.
[3-6]ドメインの形状の測定
 ドメインのサイズを評価するために、次の測定を行った。
 下記の手法に従って、走査型電子顕微鏡(SEM)で得られる観察画像を、画像処理で定量化することにより算出した。
 上記マトリックスの体積抵抗率の測定において得られた切片に対し、白金を蒸着させ蒸着切片を得た。次いで当該蒸着切片の表面を、走査型電子顕微鏡(SEM)(商品名:S-4800、(株)日立ハイテクノロジーズ製)を用いて1,000倍で撮影し、表面画像を得た。
 次いで、当該表面画像を画像処理ソフトImage-pro plus(製品名、Media Cybernetics社製)を使用して、マトリックスが白、ドメインが黒くなるように画像処理(2値化)し、カウント機能によって、観察画像内の任意の50個のドメインに対して下記の項目の算術平均値を算出した。
 なお、要件(B2)、および要件(B3)で規定したような導電層を得るために、本態様に係るドメインは、導電層の厚みをTとしたとき、該導電性の厚み方向の断面における該導電層の外表面から深さ0.1T~0.9Tまでの厚み領域の任意の位置に15μm四方の観察領域をおいたときに、該観察領域内にドメインが20個~300個存在することがより好ましい。
・周囲長:A
・包絡周囲長:B
・AとBの比:A/B
・要件(B3)を満たすドメイン個数
 これを、現像部材A1の長手方向を5等分、周方向に4等分し、当該20領域に対して上記の各項目の測定結果の算術平均値をドメインの評価用とした。
 要件3に係る「A」は、図7に示すように、観察領域で観察されるドメイン71の周囲長であり、「B」は、当該ドメインの凸包絡73の長さ(包絡周囲長)である。
 ドメイン周囲長Aおよび包絡周囲長Bの値も上記の方法による算術平均値とした。
 得られた結果を、表8-1に「周囲長A」、「包絡周囲長B」、「A/B(平均値)」、「要件(B3)を満たすドメイン個数」としてそれぞれ示した。
[3-7]ドメイン間距離の測定
 本発明に係るドメイン間の距離は、走査型電子顕微鏡(SEM)で得られる画像を観察してえられる観察画像を、画像処理することにより得た。
 具体的には、上記ドメインの形状の測定法に対して、画像処理の方法を、ドメインの壁面間距離をカウントする機能を使用した以外は、同様にして、ドメイン間距離の算出を行った。
 これを、現像ローラA1の長手方向を5等分、周方向に4等分し、当該20領域に対して上記の測定結果の算術平均をドメイン間距離(Dm)とした。
 得られた結果を、表7-1の「マトリックス」の「距離」、および表8-1の「ドメイン間距離Dm」として示した。
[3-6] Measurement of domain shape In order to evaluate the size of the domain, the following measurement was performed.
According to the following method, the observation image obtained with a scanning electron microscope (SEM) was calculated by quantifying by image processing.
Platinum was vapor-deposited on the section obtained in the measurement of the volume resistivity of the matrix to obtain a deposited section. Next, the surface of the vapor-deposited section was photographed at a magnification of 1,000 using a scanning electron microscope (SEM) (trade name: S-4800, manufactured by Hitachi High-Technologies Corporation) to obtain a surface image.
Next, the surface image is subjected to image processing (binarization) using image processing software Image-pro plus (product name, manufactured by Media Cybernetics) so that the matrix is white and the domain is black. Arithmetic average values of the following items were calculated for arbitrary 50 domains in the observed image.
In addition, in order to obtain the conductive layer as defined in the requirement (B2) and the requirement (B3), the domain according to this aspect is in the cross section of the conductive thickness direction when the thickness of the conductive layer is T. When an observation region of 15 μm square is placed at an arbitrary position in the thickness region from the outer surface of the conductive layer to a depth of 0.1 T to 0.9 T, there are 20 to 300 domains in the observation region. It is more preferable.
・ Perimeter: A
・ Envelope circumference: B
-Ratio of A and B: A / B
Number of domains satisfying the requirement (B3) This is divided into 5 equal parts in the longitudinal direction of the developing member A1 and 4 parts in the circumferential direction, and the arithmetic average value of the measurement results of the above items for each of the 20 areas is the domain It was for evaluation.
As shown in FIG. 7, “A” according to requirement 3 is the perimeter of the domain 71 observed in the observation region, and “B” is the length of the convex envelope 73 (envelope perimeter) of the domain. is there.
The values of the domain perimeter A and the envelope perimeter B were also arithmetic average values by the above method.
The obtained results are shown in Table 8-1 as “perimeter length A”, “envelope perimeter length B”, “A / B (average value)”, and “number of domains satisfying requirement (B3)”.
[3-7] Measurement of distance between domains The distance between domains according to the present invention was obtained by performing image processing on an observation image obtained by observing an image obtained with a scanning electron microscope (SEM).
Specifically, the inter-domain distance was calculated in the same manner as the above-described domain shape measurement method, except that the image processing method used a function for counting the distance between the wall surfaces of the domains.
This was divided into 5 equal parts in the longitudinal direction of the developing roller A1 and 4 parts in the circumferential direction, and the arithmetic average of the measurement results for the 20 regions was defined as the inter-domain distance (Dm).
The obtained results are shown as “distance” of “matrix” in Table 7-1 and “interdomain distance Dm” in Table 8-1.
[3-8]体積分率の測定
 ドメインの体積はFIB-SEMを用いた3次元での導電層の計測により求めることができる。
 FIB-SEMとはFIB(Focused Ion Beam:集束イオンビーム)装置で試料の加工、露出した断面のSEM(scanning electron microscope;走査型電子顕微鏡)を観察する手法である。立体的な構造を調べるためには、連続した加工・観察を繰り返して数多くの写真を取得した後、そのSEM画像をコンピュータソフトウェアで3D再構築処理を施して、試料構造を3次元的な立体像として構築することで行うことが可能となる。
 ドメイン体積の具体的な測定方法としては、FIB-SEM(エフイー・アイ社製)を使用して、3次元の立体画像を取得し、その画像から上記構成を確認した。つまり、当該導電層サンプリングは任意の9箇所からサンプリングされるが、ローラ形状の場合には、長手方向の長さをLとした時、端部から(1/4)L、(2/4)L、(3/4)L付近の三か所ずつローラの周方向に120度毎に、それぞれから各1つずつサンプルを切り出す。
 その後、FIB-SEMを用いた3次元測定を行い、60nm間隔で一辺が9μmの立方体形状の画像を測定する。ここでは、該(1/4)L、(2/4)L、(3/4)Lの各断面における導電層断面をローラの周方向に90度毎、芯金位置から表面の中心部での測定を行う。
 なお、ドメイン構造の観察を好適に実施するために、ドメインとマトリックスとのコントラストが好適に得られる前処理を施すことも好ましい。ここでは、染色処理が好適に用いることができる。
 その後得られた画像を、3D可視化・解析ソフトウェア「Avizo」(商品名、エフ・イー・アイ社製)を利用して、該一辺が9μmの立方体形状1個のサンプル中に含まれる27個の、一辺が3μmの該単位立方体におけるドメインの体積を算出する。
 なお、ドメインの隣接壁面間距離の測定も3D可視化・解析ソフトウェア Avizoを利用して同様に行うことができ、上記の測定値を得た後に、該合計27サンプルの算術平均により算出することができる。
 得られた結果を、「ドメイン体積分率」として表7-1に示す。
[3-8] Measurement of volume fraction The volume of the domain can be obtained by measuring the conductive layer in three dimensions using FIB-SEM.
FIB-SEM is a technique of processing a sample with an FIB (Focused Ion Beam) apparatus and observing an SEM (scanning electron microscope) of an exposed cross section. In order to investigate the three-dimensional structure, a series of processing and observations are repeated to obtain a large number of photographs, and then the SEM image is subjected to 3D reconstruction processing by computer software, and the sample structure is represented as a three-dimensional three-dimensional image. It becomes possible to do by constructing as.
As a specific method for measuring the domain volume, a three-dimensional stereoscopic image was obtained using FIB-SEM (manufactured by FI Eye Co., Ltd.), and the above configuration was confirmed from the image. That is, the conductive layer sampling is performed from any nine locations. In the case of a roller shape, when the length in the longitudinal direction is L, (1/4) L, (2/4) from the end. L, (3/4) Samples are cut out one by one from each of the three locations in the vicinity of L every 120 degrees in the circumferential direction of the roller.
Then, three-dimensional measurement using FIB-SEM is performed, and a cube-shaped image with sides of 9 μm is measured at intervals of 60 nm. Here, the cross section of the conductive layer in each of the (1/4) L, (2/4) L, and (3/4) L sections is 90 degrees in the circumferential direction of the roller from the position of the core bar to the center of the surface. Measure.
In order to preferably observe the domain structure, it is also preferable to perform a pretreatment that suitably obtains the contrast between the domain and the matrix. Here, a dyeing process can be suitably used.
Then, using the 3D visualization / analysis software “Avizo” (trade name, manufactured by EF Corporation), the obtained image was converted into 27 samples contained in one cube-shaped sample having a side of 9 μm. The volume of the domain in the unit cube whose side is 3 μm is calculated.
In addition, the measurement of the distance between adjacent wall surfaces of the domain can be similarly performed using 3D visualization / analysis software Avizo, and after obtaining the above measurement value, it can be calculated by the arithmetic average of the total 27 samples. .
The obtained results are shown as “domain volume fraction” in Table 7-1.
[3-9]ドメインの均一分散性
 導電層におけるドメインの均一分散性は、FIB-SEMを用いた3次元での導電層の計測により求めることができる。
 FIB-SEMとはFIB(Focused Ion Beam:集束イオンビーム)装置で試料の加工、露出した断面のSEM(scanning electron microscope;走査型電子顕微鏡)を観察する手法である。立体的な構造を調べるためには、連続した加工・観察を繰り返して数多くの写真を取得した後、そのSEM画像をコンピュータソフトウェアで3D再構築処理を施して、試料構造を3次元の立体画像として構築することで行うことが可能となる。
 具体的な測定方法としては、FIB-SEM(エフイー・アイ社製)を使用して、上述の3次元の立体画像を取得し、その画像から上記構成を確認した。
 なお、ドメイン構造の観察を好適に実施するために、ドメインとマトリックスとのコントラストが好適に得られる前処理を施すことも好ましい。ここでは、染色処理が好適に用いることができる。
 その後得られた画像を、3D可視化・解析ソフトウェア(商品名:Avizo、エフ・イー・アイ社製)を利用して、単位立方体形状のサンプル中に含まれるドメインの体積を算出する。
 なお、ドメインの隣接壁面間距離の測定も、上記の3D可視化・解析ソフトウェア Avizoを利用して同様に行うことができ、上記の測定値を得た後に、当該サンプルの算術平均により算出することができる。
 導電性のドメインが三次元的に均等かつ密に導電層中に配置された構成であることは、上記の手法で検証した。ここでは、上述したように、FIB-SEMを用いた3次元測定を行い、一辺が9μmの立方体形状のサンプル(サンプル立方体)のうち、少なくとも8個のサンプルが、以下の条件を満たすかを評価する。
要件(B1):
 「1個の立方体サンプルを、27個の、一辺が3μmの単位立方体に区分し、該単位立方体の各々に含まれる前記ドメインの体積Vdを求めたとき、Vdが2.7μm~10.8μmである単位立方体の数が少なくとも20個であること。」
 先に述べたように、要件(B1)を満たすサンプル立方体中の単位立方体の個数が増加すると、必然的に本発明の効果が高まる。
 得られた結果を「要件(B1)を満たす立方体数」として表8-1に示す。
[3-9] Uniform Dispersibility of Domain The uniform dispersibility of domains in the conductive layer can be obtained by measuring the conductive layer in three dimensions using FIB-SEM.
FIB-SEM is a technique of processing a sample with an FIB (Focused Ion Beam) apparatus and observing an SEM (scanning electron microscope) of an exposed cross section. In order to investigate the three-dimensional structure, a series of processing and observation is repeated to obtain a number of photographs, and then the SEM image is subjected to 3D reconstruction processing by computer software, so that the sample structure is converted into a three-dimensional stereoscopic image. It can be done by building.
As a specific measurement method, FIB-SEM (manufactured by FI Eye Co., Ltd.) was used to obtain the above three-dimensional stereoscopic image, and the above configuration was confirmed from the image.
In order to preferably observe the domain structure, it is also preferable to perform a pretreatment that suitably obtains the contrast between the domain and the matrix. Here, a dyeing process can be suitably used.
Thereafter, the volume of the domain contained in the unit cube-shaped sample is calculated using 3D visualization / analysis software (trade name: Avizo, manufactured by FEI Corporation).
In addition, the measurement of the distance between adjacent wall surfaces of the domain can be similarly performed using the above-mentioned 3D visualization / analysis software Avido, and after obtaining the above measurement value, it can be calculated by the arithmetic average of the sample. it can.
It was verified by the above-mentioned method that the conductive domains were three-dimensionally and uniformly arranged in the conductive layer. Here, as described above, three-dimensional measurement using FIB-SEM is performed, and it is evaluated whether at least eight samples out of the cube-shaped sample (sample cube) with a side of 9 μm satisfy the following conditions: To do.
Requirement (B1):
“When one cubic sample is divided into 27 unit cubes each having a side of 3 μm, and the volume Vd of the domain included in each unit cube is determined, Vd is 2.7 μm 3 to 10.8 μm. The number of unit cubes that are 3 must be at least 20. "
As described above, when the number of unit cubes in the sample cube satisfying the requirement (B1) is increased, the effect of the present invention is inevitably enhanced.
The obtained results are shown in Table 8-1 as “the number of cubes satisfying the requirement (B1)”.
[3-10]ドメインの断面積に対するドメインが含む該電子導電剤の断面積の割合
 上記「ドメインの形状の測定」で観察した、SEM画像を用いて算出することができる。前記手法で得られた切片に対し、白金を蒸着させ蒸着切片を得た。次いで当該蒸着切片の表面を、走査型電子顕微鏡(SEM)(製品名:S-4800、日立ハイテクノロジーズ社製)を用いて1000倍~100000倍で撮影し、表面画像を得た。次に画像に対し、画像解析装置(製品名:LUZEX-AP、ニレコ社製)を使用して、8ビットのグレースケール化を行い、256諧調のモノクロ画像を得る。次いで、破断面内のドメインが白くなるように、画像の白黒を反転処理し、2値化を実施する。
 さらに、上記のSEM像からドメイン1個が少なくとも収まる大きさの観察領域を抽出し、ドメインの断面積Sd、ドメインが含む電子導電剤(カーボンブラック)の断面積Scを算出する。
 得られた、電子導電剤(カーボンブラック)の断面積Sc、ドメインの断面積Sdより、μ=Sc/Sdを求めることで、ドメインの断面積に対するドメインが含む該電子導電剤の断面積の割合が得られる。
 得られた結果を「μ」(電子導電剤の断面積の割合の平均値)、「σ」(電子導電剤の断面積の割合の標準偏差)、「μ/σ」、「要件(B2)断面積割合(平均)」、「要件(B2)を満たすドメイン個数%」として表8-1に示す。
[3-10] Ratio of the cross-sectional area of the electronic conductive agent contained in the domain to the cross-sectional area of the domain. The ratio can be calculated using the SEM image observed in the above “Measurement of domain shape”. Platinum was vapor-deposited on the slice obtained by the above method to obtain a vapor deposition slice. Next, the surface of the vapor-deposited section was photographed at 1000 to 100,000 times using a scanning electron microscope (SEM) (product name: S-4800, manufactured by Hitachi High-Technologies Corporation) to obtain a surface image. Next, the image is converted to 8-bit gray scale using an image analysis device (product name: LUZEX-AP, manufactured by Nireco) to obtain a 256-tone monochrome image. Next, the black and white of the image is inverted so that the domain in the fracture surface becomes white, and binarization is performed.
Further, an observation region having a size that can accommodate at least one domain is extracted from the SEM image, and the cross-sectional area Sd of the domain and the cross-sectional area Sc of the electronic conductive agent (carbon black) included in the domain are calculated.
By obtaining μ = Sc / Sd from the cross-sectional area Sc and domain cross-sectional area Sd of the obtained electronic conductive agent (carbon black), the ratio of the cross-sectional area of the electronic conductive agent included in the domain to the cross-sectional area of the domain Is obtained.
The obtained results are expressed as “μ” (average value of the ratio of the cross-sectional area of the electronic conductive agent), “σ” (standard deviation of the ratio of the cross-sectional area of the electronic conductive agent), “μ / σ”, “Requirement (B2) Table 8-1 shows the “cross-sectional area ratio (average)” and “number of domains satisfying requirement (B2)%”.
[実施例2~実施例34]
 導電性支持体・ドメインゴム・マトリックスゴムの原材料・加硫剤、加硫助剤等を表5-1~表6-5に示すものに変更した以外は実施例1と同様にして、実施例2~実施例34の現像ローラを製造し、評価した。評価結果を表7-1、表7-2、表8-1および表8-2に示す。
[実施例35]
 実施例1と同じ、快削鋼の表面に無電解ニッケルメッキ処理を施した外径6mmの芯金を用意した。次にロールコーターを用いて、前記芯金の両端部15mmずつを除く範囲の全周にわたって、接着剤として「メタロックU-20」(商品名、(株)東洋化学研究所製)を塗布した。実施例35においては、前記接着剤を塗布した芯金を導電性の軸芯体として使用した。以降、導電性支持体・ドメインゴム・マトリックスゴムの原材料・加硫剤、加硫助剤等を表5-3、および表6-2~表6-5に示すものに変更した以外は実施例1と同様にして、実施例35の現像ローラを得た。
[実施例36]
 導電性熱可塑樹脂(商品名:トレカTLP1060;東レ社製)を用い、射出成形により、外径8mmの丸棒を成形した。次に丸棒を研磨し、実施例1で用いた快削鋼製のものと同じ形状の、外径6mmの導電性樹脂芯金を用意した。
 実施例36においては、本導電性樹脂芯金を導電性の軸芯体として使用した。以降、導電性支持体・ドメインゴム・マトリックスゴムの原材料・加硫剤、加硫助剤等を表5-3および表6-2~表6-5に示すものに変更した以外は実施例1と同様にして、実施例36の現像ローラを得た。
[実施例37]
 実施例36で用いた導電性樹脂芯金を用意した。次にロールコーターを用いて、前記芯金の両端部15mmずつを除く範囲の全周にわたって、接着剤としてメタロックU-20(商品名、(株)東洋化学研究所製)を塗布した。実施例37においては、前記接着剤を塗布した導電性樹脂芯金を導電性の軸芯体として使用した。
 以降、導電性支持体・ドメインゴム・マトリックスゴムの原材料・加硫剤、加硫助剤等を表5-3および表6-2~表6-5に示すものに変更した以外は実施例1と同様にして、実施例37の現像ローラを得た。
[実施例38]
 PPS樹脂(商品名:トレリナA503-X05;東レ社製)を用い、射出成形により、外径8mmの丸棒を成形した。次に丸棒を研磨し、実施例1で用いた快削鋼製のものと同じ形状の、外径6mmのPPS樹脂芯金を用意した。得られたPPS樹脂芯金の外表面の全面に白金蒸着を施し、軸芯体とした。次に実施例37と同様にして、軸芯体に接着剤を塗布した。
 以降、導電性支持体・ドメインゴム・マトリックスゴムの原材料・加硫剤、加硫助剤等を表5-3および表6-2~表6-5に示すものに変更した以外は実施例1と同様にして、実施例38の形状の現像ローラを得た。
[Examples 2 to 34]
Except that the conductive support, domain rubber, matrix rubber raw materials, vulcanizing agent, vulcanization aid, etc. were changed to those shown in Table 5-1 to Table 6-5, the same procedure as in Example 1 was carried out. Development rollers of 2 to Example 34 were manufactured and evaluated. The evaluation results are shown in Table 7-1, Table 7-2, Table 8-1 and Table 8-2.
[Example 35]
As in Example 1, a cored bar having an outer diameter of 6 mm was prepared by subjecting the surface of free-cutting steel to electroless nickel plating. Next, using a roll coater, “Metaloc U-20” (trade name, manufactured by Toyo Chemical Laboratory Co., Ltd.) was applied as an adhesive over the entire circumference excluding 15 mm at both ends of the core metal. In Example 35, the core metal coated with the adhesive was used as a conductive shaft core. Thereafter, the examples except that the raw materials, vulcanizing agents, vulcanizing aids, etc. of the conductive support, domain rubber and matrix rubber were changed to those shown in Table 5-3 and Tables 6-2 to 6-5. In the same manner as in Example 1, a developing roller of Example 35 was obtained.
[Example 36]
A round bar having an outer diameter of 8 mm was formed by injection molding using a conductive thermoplastic resin (trade name: Torayca TLP1060; manufactured by Toray Industries, Inc.). Next, the round bar was polished to prepare a conductive resin core bar having an outer diameter of 6 mm and having the same shape as that of the free-cutting steel used in Example 1.
In Example 36, this conductive resin cored bar was used as a conductive shaft core. Thereafter, Example 1 except that the conductive support, domain rubber, matrix rubber raw material, vulcanizing agent, vulcanizing auxiliary, etc. were changed to those shown in Table 5-3 and Tables 6-2 to 6-5. In the same manner as described above, the developing roller of Example 36 was obtained.
[Example 37]
The conductive resin core used in Example 36 was prepared. Next, using a roll coater, METALOC U-20 (trade name, manufactured by Toyo Chemical Laboratory Co., Ltd.) was applied as an adhesive over the entire circumference excluding 15 mm at both ends of the core metal. In Example 37, the conductive resin core metal coated with the adhesive was used as a conductive shaft core.
Thereafter, Example 1 except that the conductive support, domain rubber, matrix rubber raw material, vulcanizing agent, vulcanizing auxiliary, etc. were changed to those shown in Table 5-3 and Tables 6-2 to 6-5. In the same manner as described above, the developing roller of Example 37 was obtained.
[Example 38]
A round bar having an outer diameter of 8 mm was formed by injection molding using PPS resin (trade name: Torelina A503-X05; manufactured by Toray Industries, Inc.). Next, the round bar was polished to prepare a PPS resin core metal having an outer diameter of 6 mm and having the same shape as that of the free-cutting steel used in Example 1. Platinum vapor deposition was applied to the entire outer surface of the obtained PPS resin core bar to obtain a shaft core body. Next, an adhesive was applied to the shaft core in the same manner as in Example 37.
Thereafter, Example 1 except that the conductive support, domain rubber, matrix rubber raw material, vulcanizing agent, vulcanizing auxiliary, etc. were changed to those shown in Table 5-3 and Tables 6-2 to 6-5. In the same manner as described above, a developing roller having the shape of Example 38 was obtained.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000014
Figure JPOXMLDOC01-appb-T000014
4.現像ローラとしての評価
 得られた実施例1~実施例38に係る現像ローラについて、以下の評価を行った。
[4-1]画像(カブリ)評価(「かぶり画像」)
 各実施例および比較例に係る現像ローラを、図10に示す構成を有するレーザープリンタ(商品名:HP Color Laserjet Enterprise CP4515dn、HP社製)用のマゼンタトナーカートリッジに装填して、かぶり画像の評価を行った。高速プロセスにおける評価とするために、当該レーザープリンタを、単位時間当たりの出力枚数が、オリジナルの出力枚数よりも多い、A4サイズの用紙で、50枚/分となるように改造した。
 各現像ローラを装填したマゼンタトナーカートリッジを、上記レーザープリンタに装填し、気温32℃、相対湿度85%RHの高温高湿環境中に設置した後、6時間放置した。
 次いで、サイズが4ポイントのアルファベットの「E」の文字が、A4サイズの紙の面積に対し被覆率が1%となるように印字されるような画像(以下、「E文字画像」ともいう)を所定枚数のコピー用紙に対して連続出力した。その後、新しいコピー用紙に白ベタ画像を出力し、白ベタ画像の出力中にプリンターを停止した。この時、感光体上に付着したトナーをテープ(商品名:CT18、ニチバン社製)ではがし取り、反射濃度計(商品名:TC-6DS/A、東京電飾社製)にて反射率を測定した。テープの反射率を基準としたときの反射率の低下量(%)を測定し、これをかぶり値とした。これらのカブリ値に基づき、以下の基準で評価した。 
・ランクA:カブリ値が1.5%未満である。
・ランクB:カブリ値が1.5%以上3.0%未満である。
・ランクC:カブリ値が3.0%以上5.0%未満である。
・ランクD:カブリ値が5.0%以上である。
[4-2]トナー帯電量
 トナーに対する現像ローラの帯電付与性を評価するために、帯電量を測定した。
 上記かぶり画像評価の際に、現像ローラの、トナー規制ブレードと感光体当接位置に挟まれた部分のうち範囲が狭い部分に担持されたトナーを、金属円筒管と円筒フィルターにより吸引捕集した。その際、金属円筒管を通じてコンデンサに蓄えられた電荷量と、吸引されたトナーの質量を測定した。なお、電荷量の測定は、エーディーシー社製の測定機(商品名:8252)を用いて行った。そして、これらの値から、単位質量あたりの電荷量(μC/g)を算出した。負帯電性のトナーを用いる場合、単位質量あたりの電荷量の符号が負であり、絶対値が大きいほど、現像ローラの帯電付与性が高いといえる。測定により得られた値をトナー帯電量とした。
[4-3]トナー帯電量分布
 トナーの帯電量の広がりを評価するために、帯電量分布を測定した。
 帯電量分布は、E-spart Analyzer Model EST-III(ホソカワミクロン社製)を用いて測定した。それ以外は、トナーの帯電量測定と同様にして、帯電量分布を測定した。なお、測定粒子個数は3000個程度とした。得られた帯電量分布から、標準偏差を算出し、得られた値をトナーの初期帯電量分布とした。
 評価結果を表8-1、表8-2に示す。
4). Evaluation as developing roller The following evaluations were performed on the developing rollers according to Examples 1 to 38 obtained.
[4-1] Image (fogging) evaluation (“cover image”)
The developing roller according to each of the examples and the comparative example is loaded into a magenta toner cartridge for a laser printer (trade name: HP Color Laserjet Enterprise CP4515dn, manufactured by HP) having the configuration shown in FIG. went. In order to evaluate it in a high-speed process, the laser printer was modified so that the number of output sheets per unit time was 50 sheets / minute with A4 size paper, which is larger than the original output number.
The magenta toner cartridge loaded with each developing roller was loaded into the laser printer and placed in a high temperature and high humidity environment with a temperature of 32 ° C. and a relative humidity of 85% RH, and then left for 6 hours.
Next, an image in which the letter “E” of the 4-point alphabet is printed so that the coverage is 1% with respect to the area of the A4 size paper (hereinafter also referred to as “E character image”). Was continuously output on a predetermined number of copy sheets. After that, a solid white image was output on a new copy sheet, and the printer was stopped while the solid white image was being output. At this time, the toner adhering to the photosensitive member is removed with a tape (trade name: CT18, manufactured by Nichiban Co., Ltd.), and the reflectance is measured with a reflection densitometer (trade name: TC-6DS / A, manufactured by Tokyo Electric Decoration Co., Ltd.). Was measured. The amount of decrease in reflectance (%) with respect to the reflectance of the tape was measured, and this was used as the fog value. Based on these fog values, the following criteria were used for evaluation.
Rank A: The fog value is less than 1.5%.
Rank B: The fog value is 1.5% or more and less than 3.0%.
Rank C: The fog value is 3.0% or more and less than 5.0%.
Rank D: The fog value is 5.0% or more.
[4-2] Toner charge amount In order to evaluate the charging property of the developing roller to the toner, the charge amount was measured.
During the above fog image evaluation, the toner carried on the narrow portion of the portion of the developing roller sandwiched between the toner regulating blade and the photoreceptor contact position was sucked and collected by the metal cylindrical tube and the cylindrical filter. . At that time, the amount of charge stored in the capacitor through the metal cylindrical tube and the mass of the sucked toner were measured. The charge amount was measured using a measuring machine (trade name: 8252) manufactured by ADC. From these values, the charge amount per unit mass (μC / g) was calculated. When using a negatively chargeable toner, the sign of the charge amount per unit mass is negative, and the larger the absolute value, the higher the charge imparting property of the developing roller. The value obtained by the measurement was defined as the toner charge amount.
[4-3] Toner Charge Amount Distribution In order to evaluate the spread of the toner charge amount, the charge amount distribution was measured.
The charge amount distribution was measured using an E-spar Analyzer Model EST-III (manufactured by Hosokawa Micron Corporation). Otherwise, the charge amount distribution was measured in the same manner as the toner charge amount measurement. The number of measured particles was about 3000. The standard deviation was calculated from the obtained charge amount distribution, and the obtained value was used as the initial charge amount distribution of the toner.
The evaluation results are shown in Tables 8-1 and 8-2.
Figure JPOXMLDOC01-appb-T000015
Figure JPOXMLDOC01-appb-T000015
Figure JPOXMLDOC01-appb-T000016
Figure JPOXMLDOC01-appb-T000016
Figure JPOXMLDOC01-appb-T000017
Figure JPOXMLDOC01-appb-T000017
Figure JPOXMLDOC01-appb-T000018
Figure JPOXMLDOC01-appb-T000018
[比較例1]
 表9に示す量の各材料を加圧式ニーダーで混合しマスターバッチを得た。混合機は、6リットル加圧ニーダー(製品名:TD6-15MDX、トーシン社製)を用いた。混合条件は、充填率70vol%、ブレード回転数30rpm、16分間とした。
 本材料を現像ローラ成形用ゴム組成物とし、以降は実施例1と同様にして、比較例1の現像ローラを得た。
[Comparative Example 1]
The materials shown in Table 9 were mixed with a pressure kneader to obtain a master batch. A 6-liter pressure kneader (product name: TD6-15MDX, manufactured by Toshin Co., Ltd.) was used as the mixer. The mixing conditions were a filling rate of 70 vol%, a blade rotation speed of 30 rpm, and 16 minutes.
This material was used as a developing roller molding rubber composition, and thereafter, a developing roller of Comparative Example 1 was obtained in the same manner as in Example 1.
Figure JPOXMLDOC01-appb-T000019
Figure JPOXMLDOC01-appb-T000019
[比較例2]
 現像ローラ成形用ゴム組成物を表10に示すものに変更した以外は比較例1と同様にして、比較例2の現像ローラを得た。
[Comparative Example 2]
A developing roller of Comparative Example 2 was obtained in the same manner as Comparative Example 1, except that the rubber composition for molding the developing roller was changed to that shown in Table 10.
Figure JPOXMLDOC01-appb-T000020
Figure JPOXMLDOC01-appb-T000020
[比較例3]
 表11に示す量の各材料を加圧式ニーダーで混合し未加硫ドメイン組成物を得た。混合機は、6リットル加圧ニーダー(製品名:TD6-15MDX、トーシン社製)を用いた。混合条件は、充填率70vol%、ブレード回転数30rpm、16分間とした。
[Comparative Example 3]
The materials shown in Table 11 were mixed with a pressure kneader to obtain an unvulcanized domain composition. A 6-liter pressure kneader (product name: TD6-15MDX, manufactured by Toshin Co., Ltd.) was used as the mixer. The mixing conditions were a filling rate of 70 vol%, a blade rotation speed of 30 rpm, and 16 minutes.
Figure JPOXMLDOC01-appb-T000021
Figure JPOXMLDOC01-appb-T000021
 次に、表12に示す量の各材料を加圧式ニーダーで混合し未加硫マトリックス組成物を得た。混合機は、6リットル加圧ニーダー(製品名:TD6-15MDX、トーシン社製)を用いた。混合条件は、充填率70vol%、ブレード回転数30rpm、16分間とした。 Next, the materials shown in Table 12 were mixed with a pressure kneader to obtain an unvulcanized matrix composition. A 6-liter pressure kneader (product name: TD6-15MDX, manufactured by Toshin Co., Ltd.) was used as the mixer. The mixing conditions were a filling rate of 70 vol%, a blade rotation speed of 30 rpm, and 16 minutes.
Figure JPOXMLDOC01-appb-T000022
Figure JPOXMLDOC01-appb-T000022
 次に、表13に示す量の各材料を加圧式ニーダーで混合して未加硫ゴム組成物を得た。混合機は、6リットル加圧ニーダー(製品名:TD6-15MDX、トーシン社製)を用いた。混合条件は、充填率70vol%、ブレード回転数30rpm、16分間とした。 Next, the materials shown in Table 13 were mixed with a pressure kneader to obtain an unvulcanized rubber composition. A 6-liter pressure kneader (product name: TD6-15MDX, manufactured by Toshin Co., Ltd.) was used as the mixer. The mixing conditions were a filling rate of 70 vol%, a blade rotation speed of 30 rpm, and 16 minutes.
Figure JPOXMLDOC01-appb-T000023
Figure JPOXMLDOC01-appb-T000023
 次に、表14に示す量の各材料をオープンロールにて混合し導電性部材成形用ゴム組成物を調製した。混合機は、ロール径12インチ(0.30m)のオープンロールを用いた。混合条件は、前ロール回転数10rpm、後ロール回転数8rpmで、ロール間隙2mmとして合計20回左右の切り返しを行った後、ロール間隙を0.5mmとして10回薄通しを行った。 Next, each material in the amount shown in Table 14 was mixed with an open roll to prepare a rubber composition for forming a conductive member. As the mixer, an open roll having a roll diameter of 12 inches (0.30 m) was used. The mixing conditions were a front roll rotation speed of 10 rpm and a rear roll rotation speed of 8 rpm, and after turning left and right a total of 20 times with a roll gap of 2 mm, thinning was performed 10 times with a roll gap of 0.5 mm.
Figure JPOXMLDOC01-appb-T000024
Figure JPOXMLDOC01-appb-T000024
 本材料を現像ローラ成形用ゴム組成物とし、以降は実施例1と同様にして、比較例3の現像ローラを得た。
[比較例4~比較例8、比較例12]
 導電性支持体・ドメインゴム・マトリックスゴムの原材料・加硫剤、加硫助剤を表16、表17に示すものに変更した以外は比較例3と同様に比較例4~比較例8、および比較例12の現像ローラを得た。
[比較例9]
 現像ローラ成形用ゴム組成物を表16、表17に示すものに変更した以外は比較例1と同様にして、ヒドリンゴムからなる弾性層を形成した。
 次いで、表15の材料をメタノール:1-ブタノール=3:1に加え、固形分が10質量%となるように調整した。
 次いで、450mLのガラス瓶に上記混合溶液210gと、メディアとして平均粒径0.8mmのガラスビーズ200gとを混合し、ペイントシェーカー分散機を用いて24時間前分散を行い、導電性樹脂層形成用の塗料を得た。
 前記ヒドリンゴムからなる弾性層を、その長手方向を鉛直方向にして、前記導電性樹脂層形成用の塗料中に浸漬してディッピング法で塗工した。ディッピング塗布の浸漬時間は9秒間、引き上げ速度は、初期速度が20mm/sec、最終速度が2mm/sec、その間は時間に対して直線的に速度を変化させた。得られた塗工物を常温で30分間風乾し、次いで90℃に設定した熱風循環乾燥機中において1時間乾燥し、さらに160℃に設定した熱風循環乾燥機中において1時間乾燥し、比較例9の現像ローラを得た。
This material was used as a developing roller molding rubber composition, and thereafter, a developing roller of Comparative Example 3 was obtained in the same manner as in Example 1.
[Comparative Examples 4 to 8 and Comparative Example 12]
Comparative Example 4 to Comparative Example 8 as in Comparative Example 3 except that the conductive support, domain rubber, matrix rubber raw material, vulcanizing agent, and vulcanization aid were changed to those shown in Tables 16 and 17. A developing roller of Comparative Example 12 was obtained.
[Comparative Example 9]
An elastic layer made of hydrin rubber was formed in the same manner as in Comparative Example 1 except that the developing roller molding rubber composition was changed to those shown in Tables 16 and 17.
Next, the materials shown in Table 15 were added to methanol: 1-butanol = 3: 1 to adjust the solid content to 10% by mass.
Next, 210 g of the above mixed solution and 200 g of glass beads having an average particle diameter of 0.8 mm are mixed as a medium in a 450 mL glass bottle and pre-dispersed for 24 hours using a paint shaker disperser to form a conductive resin layer. A paint was obtained.
The elastic layer made of the hydrin rubber was immersed in the coating material for forming the conductive resin layer with its longitudinal direction set to the vertical direction, and applied by dipping. The dipping coating immersion time was 9 seconds, the pulling speed was 20 mm / sec for the initial speed, 2 mm / sec for the final speed, and the speed was changed linearly with respect to the time. The obtained coated material was air-dried at room temperature for 30 minutes, then dried in a hot air circulating dryer set at 90 ° C. for 1 hour, and further dried in a hot air circulating dryer set at 160 ° C. for 1 hour. 9 developing rollers were obtained.
Figure JPOXMLDOC01-appb-T000025
Figure JPOXMLDOC01-appb-T000025
[比較例10]
 現像ローラ成形用ゴム組成物を表16、表17に示すものに変更した以外は比較例1と同様にして、比較例10の現像ローラを得た。
[比較例11]
 導電性支持体・マトリックスゴムの原材料・加硫剤、加硫助剤を表16、表17に示すものに変更し、ドメインゴム材料を単独で加熱加硫した後に、凍結粉砕したゴム粒子に変更した以外は実施例1と同様にして、比較例11の現像ローラを得た。本比較例においては、凍結粉砕によって形成した、サイズが大きく、異方性のある導電ゴム粒子を分散しているために、導電部材内での導電パスが不均一に形成されるため、ドメインの厚みが大きい状態と同義になる。その結果、インピーダンスの高周波数における傾きが-1となっている。
 比較例1~比較例12において得られた現像ローラを実施例1と同様にして評価した結果を表18、表19に示す。
[Comparative Example 10]
A developing roller of Comparative Example 10 was obtained in the same manner as Comparative Example 1 except that the rubber composition for molding the developing roller was changed to those shown in Tables 16 and 17.
[Comparative Example 11]
The raw materials, vulcanizing agents, and vulcanization aids for the conductive support / matrix rubber were changed to those shown in Tables 16 and 17, and the domain rubber material was vulcanized by heating alone and then changed to freeze-pulverized rubber particles. A developing roller of Comparative Example 11 was obtained in the same manner as in Example 1 except that. In this comparative example, since the conductive rubber particles having a large size and anisotropic formed by freeze pulverization are dispersed, the conductive path in the conductive member is formed unevenly. It is synonymous with a state where the thickness is large. As a result, the slope of impedance at high frequency is -1.
Tables 18 and 19 show the results of evaluating the developing rollers obtained in Comparative Examples 1 to 12 in the same manner as in Example 1.
Figure JPOXMLDOC01-appb-T000026
Figure JPOXMLDOC01-appb-T000026
Figure JPOXMLDOC01-appb-T000027
Figure JPOXMLDOC01-appb-T000027
Figure JPOXMLDOC01-appb-T000028
Figure JPOXMLDOC01-appb-T000028
Figure JPOXMLDOC01-appb-T000029
Figure JPOXMLDOC01-appb-T000029
 実施例1~実施例38に係る現像ローラは、導電層に、本発明の構成を有しているため、帯電量分布がシャープであり、カブリの数値も非常に小さい高品位な画像が得られた。それに対し、本発明に係る導電層を有しない比較例1~比較例12に係る現像ローラでは、帯電量分布が大きく、画像品質が良好でなかった。
5.現像ブレードとしての評価
<1.現像ブレードの作製>
[実施例39]
 実施例2で得た未加硫ゴム組成物を使用した。ここでは、未加硫ゴム組成物を幅250mm、長さ150mm、厚さ0.7mmの金型に加圧プレス機で加圧しながら、160℃で10分処理することで、対応する厚さ0.7mmのゴムシート1を得た。
 ゴムシート1を幅215mm、長さ12mmに切断し、予め所定のカートリッジに取り付けられるように加工した板金(後述の電子写真用プロセスカートリッジの現像ブレードに用いられている板金と同形状)に接着剤を用いて接着し、実施例39の現像ブレードを得た。この時、現像ブレードは長さ12mmのうち板金と重なる部分を4.5mmとし、残りの7.5mmを板金からはみ出るように接着した。なお、接着剤は、導電性のホットメルトタイプのものを使用した。
Since the developing roller according to Examples 1 to 38 has the configuration of the present invention in the conductive layer, a high-quality image with a sharp charge amount distribution and a very small fog value can be obtained. It was. On the other hand, in the developing rollers according to Comparative Examples 1 to 12 having no conductive layer according to the present invention, the charge amount distribution was large and the image quality was not good.
5). Evaluation as developing blade <1. Production of development blade>
[Example 39]
The unvulcanized rubber composition obtained in Example 2 was used. Here, the unvulcanized rubber composition is treated at 160 ° C. for 10 minutes while pressing it with a pressure press machine onto a mold having a width of 250 mm, a length of 150 mm, and a thickness of 0.7 mm, thereby obtaining a corresponding thickness of 0. A rubber sheet 1 of 7 mm was obtained.
The rubber sheet 1 is cut into a width of 215 mm and a length of 12 mm, and an adhesive is applied to a sheet metal (same shape as that used for a developing blade of an electrophotographic process cartridge described later) that has been processed in advance to be attached to a predetermined cartridge. To obtain a developing blade of Example 39. At this time, the developing blade was bonded so that the portion of 12 mm in length overlapping with the sheet metal was 4.5 mm, and the remaining 7.5 mm was protruded from the sheet metal. The adhesive used was a conductive hot melt type.
 2.特性評価
[2-1]インピーダンスの傾きの測定
 本発明に係るインピーダンスの測定は、次のようにして行った。
 まず、前処理として、現像ブレードに対し、銀ペーストを塗布することよって、測定電極を作成した。この時、マスキングテープを使用して、現像ブレードの板金を接着しない面の、先端1mmから6mmの部位に、長さ213mmmの長方形の電極を作成した。次に、当該電極に銀ペーストを用いて導線を貼り付け、アルミシートから、インピーダンス測定装置(商品名:ソーラトロン1260、およびソーラトロン1296;ソーラトロン社製)の測定電極に接続した。
 インピーダンスの測定は、温度23℃、相対湿度50%の環境において、振動電圧1Vpp、直流10V、周波数1.0×10-2Hz~1.0×10Hzで測定(周波数が1桁変化する際に、5点ずつ測定)し、インピーダンスの絶対値を得た。次いで、測定結果をエクセルなどの表計算ソフトを用いて、当該インピーダンスの絶対値と、角周波数(測定周波数×2×π(円周率))を両対数プロットし、1.0×10Hz~1.0×10Hzにおける傾きを算出した。また、上記インピーダンスの傾きの測定において、1.0×10-2Hz~1.0×10Hzにおけるインピーダンスを算出した。
 インピーダンス以外の評価は、現像ローラと同様に測定を行った。
[実施例40~実施例44]
 導電性支持体・ドメインゴム・マトリックスゴムの原材料・加硫剤、加硫助剤を表20、表21に示すものに変更した以外は実施例39と同様に実施例40~実施例44の現像ブレードを製造した。なお、表20における「Zeospan」は、日本ゼオン社製のポリエーテル系合成ゴムである。
[比較例13~比較例17]
 導電性支持体・ドメインゴム・マトリックスゴムの原材料・加硫剤、加硫助剤を表22、表23に示すものに変更した以外は実施例39と同様にして、比較例13~比較例17の現像ブレードを製造した。
2. Characteristic Evaluation [2-1] Measurement of Impedance Slope Impedance measurement according to the present invention was performed as follows.
First, as a pretreatment, a measurement electrode was prepared by applying a silver paste to a developing blade. At this time, using a masking tape, a rectangular electrode having a length of 213 mm was formed at a portion of the tip from 1 mm to 6 mm on the surface where the sheet metal of the developing blade was not bonded. Next, a conductive wire was attached to the electrode using a silver paste, and the aluminum sheet was connected to a measurement electrode of an impedance measuring device (trade names: Solartron 1260 and Solartron 1296; manufactured by Solartron).
The impedance is measured at an oscillation voltage of 1 Vpp, a direct current of 10 V, and a frequency of 1.0 × 10 −2 Hz to 1.0 × 10 7 Hz in an environment of a temperature of 23 ° C. and a relative humidity of 50% (the frequency changes by an order of magnitude. In this case, measurement was performed at 5 points) to obtain an absolute value of impedance. Next, using spreadsheet software such as Excel, the absolute value of the impedance and the angular frequency (measurement frequency × 2 × π (circumferential ratio)) are log-logged and the measurement result is 1.0 × 10 6 Hz. The slope at ˜1.0 × 10 7 Hz was calculated. Further, in the measurement of the slope of the impedance, the impedance at 1.0 × 10 −2 Hz to 1.0 × 10 0 Hz was calculated.
Evaluations other than the impedance were measured in the same manner as the developing roller.
[Examples 40 to 44]
Development of Examples 40 to 44 in the same manner as in Example 39 except that the conductive support, domain rubber, matrix rubber raw material, vulcanizing agent, and vulcanization aid were changed to those shown in Tables 20 and 21. A blade was manufactured. Note that “Zeospan” in Table 20 is a polyether synthetic rubber manufactured by Nippon Zeon.
[Comparative Examples 13 to 17]
Comparative Examples 13 to 17 were the same as Example 39 except that the conductive support, domain rubber, matrix rubber raw materials, vulcanizing agent, and vulcanization aid were changed to those shown in Tables 22 and 23. The developing blade was manufactured.
Figure JPOXMLDOC01-appb-T000030
Figure JPOXMLDOC01-appb-T000030
Figure JPOXMLDOC01-appb-T000031
Figure JPOXMLDOC01-appb-T000031
Figure JPOXMLDOC01-appb-T000032
Figure JPOXMLDOC01-appb-T000032
Figure JPOXMLDOC01-appb-T000033
Figure JPOXMLDOC01-appb-T000033
3.現像ブレードとしての評価
[3-1]画像(カブリ)評価
 現像ブレードの高速プロセスにおける、持続性のある帯電付与性確認のため、以下の評価を実施した。
 まず、現像ブレードを測定環境にならす目的で、温度23℃、相対湿度50%の環境に48時間放置した。次に、電子写真装置として、電子写真方式のレーザープリンタ(商品名:Laserjet M608dn、HP社製)を用意した。そして、本電子写真装置に搭載可能なプロセスカートリッジを用意し、当該プロセスカートリッジの現像部材として、実施例39~実施例44、比較例13~比較例17の各現像ブレードを個々に組み込んだ。
 高速プロセスにおける評価とするために、当該レーザープリンタを、単位時間当たりの出力枚数が、オリジナルの出力枚数よりも多い、A4サイズの用紙で、75枚/分となるように改造した。その際、記録メディアの出力スピードは370mm/秒、画像解像度は1,200dpiとした。また、温度23℃、相対湿度50%の環境に48時間放置した。
 上記電子写真装置において、現像ブレードへの電圧印加電極へ外部電源によって電圧印加可能にする改造を施し、現像スリーブの金属部と現像ブレードの板金を電気的に接続した。
 温度30℃、相対湿度95%の環境下に上記プロセスカートリッジを4時間放置後、同環境下にて印字率0%のベタ白画像を記録用紙に出力し、印字途中でカラーレーザープリンタの電源を落とす。この時の感光体と現像スリーブのニップ通過前の現像スリーブ上のトナーの帯電量Q/M(μC/g)を測定する。具体的なトナーの帯電量の測定は、現像ローラの評価と同様である。1本の現像スリーブに対して、上記操作を3回繰り返しトナーの帯電量を3回測定し、それらの相加平均値を求め、本発明の現像ブレードを使用した際のトナー帯電量とする。 
 さらに、ベタ白画像を出力中にプリンターを停止した際に、転写される前の感光体上に付着した現像剤をテープではがし取り、反射濃度計(商品名:TC-6DS/A;東京電色社製)にてテープの反射率Rを測定し、未使用のテープの反射率R基準に対する反射率の低下量「R-R」(%)を算出し、これカブリ値とする。これらのカブリ値に基づき、以下の基準で評価した。 
・ランクA:カブリ値が1.5%未満である。
・ランクB:カブリ値が1.5%以上3.0%未満である。
・ランクC:カブリ値が3.0%以上5.0%未満である。
・ランクD:カブリ値が5.0%以上である。
[3-2]トナー帯電量
 トナーに対する現像ブレードの帯電付与性を評価するために、帯電量を測定した。
 上記かぶり画像評価の際に、現像スリーブの、現像ブレードと感光体当接位置に挟まれた部分のうち範囲が狭い部分に担持されたトナーを、金属円筒管と円筒フィルターにより吸引捕集した。その際、金属円筒管を通じてコンデンサに蓄えられた電荷量と、吸引されたトナーの質量を測定した。なお、電荷量の測定は、エーディーシー社製の測定機(商品名:8252)を用いて行った。そして、これらの値から、単位質量あたりの電荷量(μC/g)を算出した。負帯電性のトナーを用いる場合、単位質量あたりの電荷量の符号が負であり、絶対値が大きいほど、現像ブレードの帯電付与性が高いといえる。測定により得られた値を帯電量とした。
[3-3]トナー帯電量分布
 トナーの帯電量の広がりを評価するために、帯電量分布を測定した。
 帯電量分布は、E-spart Analyzer Model EST-III(ホソカワミクロン社製)を用いて測定した。それ以外は、トナー帯電量測定と同様にして、帯電量分布を測定した。なお、測定粒子個数は3000個程度とした。得られた帯電量分布から、標準偏差を算出し、得られた値をトナーの初期帯電量分布とした。
 評価結果を表24~表27に示す。
3. Evaluation as a developing blade [3-1] Image (fogging) evaluation The following evaluation was carried out in order to confirm a sustained charge imparting property in a high-speed process of a developing blade.
First, in order to adjust the developing blade to the measurement environment, the developing blade was left in an environment of a temperature of 23 ° C. and a relative humidity of 50% for 48 hours. Next, an electrophotographic laser printer (trade name: Laserjet M608dn, manufactured by HP) was prepared as an electrophotographic apparatus. Then, a process cartridge that can be mounted on the electrophotographic apparatus was prepared, and the developing blades of Example 39 to Example 44 and Comparative Example 13 to Comparative Example 17 were individually incorporated as developing members of the process cartridge.
In order to evaluate in a high-speed process, the laser printer was modified so that the number of output sheets per unit time was 75 sheets / minute with A4 size paper, which was larger than the original output number. At that time, the output speed of the recording medium was 370 mm / second, and the image resolution was 1,200 dpi. Further, it was left for 48 hours in an environment of a temperature of 23 ° C. and a relative humidity of 50%.
In the electrophotographic apparatus, the voltage application electrode to the developing blade was modified to allow voltage application by an external power source, and the metal portion of the developing sleeve and the sheet metal of the developing blade were electrically connected.
After leaving the process cartridge for 4 hours in an environment with a temperature of 30 ° C and a relative humidity of 95%, a solid white image with a printing rate of 0% is output to the recording paper in the same environment, and the color laser printer is turned on during printing. Drop it. At this time, the charge amount Q / M (μC / g) of the toner on the developing sleeve before passing through the nip between the photosensitive member and the developing sleeve is measured. The specific measurement of the toner charge amount is the same as the evaluation of the developing roller. The above operation is repeated three times for one developing sleeve, and the charge amount of the toner is measured three times, and the arithmetic average value thereof is obtained to obtain the toner charge amount when the developing blade of the present invention is used.
Further, when the printer is stopped while outputting a solid white image, the developer adhering to the photoconductor before being transferred is peeled off with a tape, and a reflection densitometer (trade name: TC-6DS / A; Tokyo, Japan). The reflectance R 1 of the tape is measured by Denki Co., Ltd., and the amount of decrease in reflectance “R 0 -R 1 ” (%) relative to the reflectance R 0 standard of the unused tape is calculated. And Based on these fog values, the following criteria were used for evaluation.
Rank A: The fog value is less than 1.5%.
Rank B: The fog value is 1.5% or more and less than 3.0%.
Rank C: The fog value is 3.0% or more and less than 5.0%.
Rank D: The fog value is 5.0% or more.
[3-2] Toner Charge Amount In order to evaluate the charge imparting property of the developing blade to the toner, the charge amount was measured.
During the above fog image evaluation, the toner carried on the narrow portion of the portion of the developing sleeve sandwiched between the developing blade and the photoreceptor contact position was sucked and collected by the metal cylindrical tube and the cylindrical filter. At that time, the amount of charge stored in the capacitor through the metal cylindrical tube and the mass of the sucked toner were measured. The charge amount was measured using a measuring machine (trade name: 8252) manufactured by ADC. From these values, the charge amount per unit mass (μC / g) was calculated. When a negatively chargeable toner is used, it can be said that the charge imparting property of the developing blade is higher as the sign of the charge amount per unit mass is negative and the absolute value is larger. The value obtained by measurement was defined as the charge amount.
[3-3] Toner Charge Amount Distribution To evaluate the spread of the toner charge amount, the charge amount distribution was measured.
The charge amount distribution was measured using an E-spar Analyzer Model EST-III (manufactured by Hosokawa Micron Corporation). Otherwise, the charge amount distribution was measured in the same manner as the toner charge amount measurement. The number of measured particles was about 3000. The standard deviation was calculated from the obtained charge amount distribution, and the obtained value was used as the initial charge amount distribution of the toner.
The evaluation results are shown in Tables 24 to 27.
Figure JPOXMLDOC01-appb-T000034
Figure JPOXMLDOC01-appb-T000034
Figure JPOXMLDOC01-appb-T000035
Figure JPOXMLDOC01-appb-T000035
Figure JPOXMLDOC01-appb-T000036
Figure JPOXMLDOC01-appb-T000036
Figure JPOXMLDOC01-appb-T000037
Figure JPOXMLDOC01-appb-T000037
 実施例39~実施例44に係る現像ブレードは、導電層に、本発明の構成を有しているため、帯電量分布がシャープであり、カブリの数値も非常に小さい高品位な画像が得られた。
 それに対し、比較例13~比較例17に係る現像ブレードでは、トナー帯電量分布が大きく、画像品質が良好でなかった。
Since the developing blades according to Examples 39 to 44 have the configuration of the present invention in the conductive layer, a high-quality image with a sharp charge distribution and a very small fog value can be obtained. It was.
On the other hand, in the developing blades according to Comparative Examples 13 to 17, the toner charge amount distribution was large and the image quality was not good.
 本発明は上記実施の形態に制限されるものではなく、本発明の精神および範囲から離脱することなく、様々な変更および変形が可能である。従って、本発明の範囲を公にするために以下の請求項を添付する。 The present invention is not limited to the above embodiment, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, in order to make the scope of the present invention public, the following claims are attached.
 本願は、2018年4月18日提出の日本国特許出願特願2018-079952、2019年2月26日提出の日本国特許出願特願2019-032936および2019年3月29日提出の日本国特許出願特願2019-069099を基礎として優先権を主張するものであり、その記載内容の全てをここに援用する。 The present application is Japanese Patent Application Japanese Patent Application No. 2018-079552 filed on April 18, 2018, Japanese Patent Application Japanese Patent Application No. 2019-032936 filed on February 26, 2019, and Japanese Patent Application filed on March 29, 2019. The priority is claimed on the basis of Japanese Patent Application No. 2019-069099, the entire contents of which are incorporated herein by reference.
 1A 電子写真用ローラ
 1B 電子写真用ブレード
 2 支持体
 3 導電層
 6a ドメイン
 6b マトリックス
1A Electrophotographic roller 1B Electrophotographic blade 2 Support body 3 Conductive layer 6a Domain 6b Matrix

Claims (10)

  1.  導電性の外表面を有する支持体と、該支持体の外表面上に設けられた導電層を有する電子写真用の現像部材であって、
     該導電層は、第一のゴムを含むマトリックスと、該マトリックス中に分散された複数個のドメインとを有し、
     該ドメインは、第二のゴムおよび電子導電剤を含み、該現像部材の外表面に金属膜を設け、温度23℃、相対湿度50%の環境下で、該支持体の該外表面と該金属膜との間に振幅が1Vの交流電圧を、周波数1.0×10-2Hz~1.0×10Hzの間で変化させながら印加することによってインピーダンスを測定し、周波数を横軸、インピーダンスを縦軸に両対数プロットしたときの、周波数1.0×10Hz~1.0×10Hzにおける傾きが、-0.8以上、-0.3以下であり、かつ、周波数が1.0×10-2Hz~1.0×10Hzにおけるインピーダンスが、1.0×10Ω~1.0×1011Ωであることを特徴とする現像部材。
    An electrophotographic developing member having a support having a conductive outer surface, and a conductive layer provided on the outer surface of the support,
    The conductive layer has a matrix containing a first rubber and a plurality of domains dispersed in the matrix,
    The domain includes a second rubber and an electronic conductive agent, a metal film is provided on the outer surface of the developing member, and the outer surface of the support and the metal are provided in an environment of a temperature of 23 ° C. and a relative humidity of 50%. Impedance is measured by applying an AC voltage with an amplitude of 1 V between the film and the frequency while changing between a frequency of 1.0 × 10 −2 Hz to 1.0 × 10 7 Hz. When impedance is plotted on a logarithmic scale on the vertical axis, the slope at a frequency of 1.0 × 10 6 Hz to 1.0 × 10 7 Hz is −0.8 or more and −0.3 or less, and the frequency is A developing member, wherein an impedance in a range of 1.0 × 10 −2 Hz to 1.0 × 10 0 Hz is 1.0 × 10 4 Ω to 1.0 × 10 11 Ω.
  2.  前記導電層が、前記支持体の外表面上に直接設けられている請求項1に記載の現像部材。 The developing member according to claim 1, wherein the conductive layer is provided directly on the outer surface of the support.
  3.  前記導電層と、前記支持体の外表面との間に導電性の樹脂層をさらに有し、該樹脂層の外表面に前記金属膜を設け、温度23℃、相対湿度50%の環境下で、該支持体の外表面と該金属膜との間に振幅が1Vの交流電圧を、周波数1.0×10-2Hz~1.0×10Hzの間で変化させながら印加することによってインピーダンスを測定し、周波数を横軸、インピーダンスを縦軸に両対数プロットしたときの、周波数が1.0×10-2Hz~1.0×10Hzにおけるインピーダンスが、1.0×10-5Ω~1.0×10Ωである請求項1に記載の現像部材。 A conductive resin layer is further provided between the conductive layer and the outer surface of the support, and the metal film is provided on the outer surface of the resin layer, in an environment at a temperature of 23 ° C. and a relative humidity of 50%. By applying an AC voltage having an amplitude of 1 V between the outer surface of the support and the metal film while changing the frequency between 1.0 × 10 −2 Hz and 1.0 × 10 7 Hz. Impedance is measured, and the frequency is 1.0 × 10 −2 Hz to 1.0 × 10 0 Hz when the frequency is plotted on the horizontal axis and the impedance is plotted on the vertical axis, the impedance is 1.0 × 10 The developing member according to claim 1, wherein the developing member is 5 Ω to 1.0 × 10 1 Ω.
  4.  前記マトリックスの体積抵抗率が1.0×1012Ω・cmより大きく、1.0×1017Ω・cm以下である請求項1~3のいずれか一項に記載の現像部材。 The developing member according to any one of claims 1 to 3, wherein the matrix has a volume resistivity of more than 1.0 x 10 12 Ω · cm and 1.0 x 10 17 Ω · cm or less.
  5.  前記ドメイン間距離の算術平均値Dmが0.2μm以上、2.0μm以下である請求項1~4のいずれか一項に記載の現像部材。 The developing member according to any one of claims 1 to 4, wherein an arithmetic average value Dm of the inter-domain distance is 0.2 µm or more and 2.0 µm or less.
  6.  前記支持体が円柱状の支持体であり、該円柱状の支持体の外表面に前記導電層を有する請求項1~5のいずれか一項に記載の現像部材。 The developing member according to any one of claims 1 to 5, wherein the support is a cylindrical support, and the conductive layer is provided on an outer surface of the cylindrical support.
  7.  前記導電層の厚さTが100μm以上であり、前記円柱状の支持体の長手方向の長さをLとしたとき、該導電層の長手方向の中央、および該導電層の両端から中央に向かってL/4の3か所における、該導電層の厚さ方向の断面の各々について、該弾性層の外表面から深さ0.1T~0.9Tまでの厚み領域の任意の3か所に15μm四方の観察領域を置いたときに、全9個の該観察領域の各々で観察されるドメインのうちの80個数%以上が、下記要件(1)および要件(2)を満たす請求項1~6のいずれか一項に記載の現像部材:
    (1)ドメインの断面積に対する該ドメインが含む該電子導電剤の断面積の割合が、20%以上であること;
    (2)ドメインの周囲長をA、該ドメインの包絡周囲長をBとしたとき、A/Bが、1.00以上、1.10以下であること。
    When the thickness T of the conductive layer is 100 μm or more and the length in the longitudinal direction of the columnar support is L, the length of the conductive layer extends from the center in the longitudinal direction and from both ends of the conductive layer to the center. For each of the cross sections in the thickness direction of the conductive layer at three locations of L / 4, at any three locations in the thickness region from the outer surface of the elastic layer to a depth of 0.1T to 0.9T When a 15 μm square observation region is placed, 80% by number or more of the domains observed in each of the nine observation regions satisfy the following requirements (1) and (2): The developing member according to any one of 6:
    (1) The ratio of the cross-sectional area of the electronic conductive agent included in the domain to the cross-sectional area of the domain is 20% or more;
    (2) A / B is 1.00 or more and 1.10 or less, where A is the perimeter of the domain and B is the perimeter of the envelope of the domain.
  8.  前記導電層の厚み方向の断面に現れるドメインの各々の断面積に対する該ドメインの各々が含む前記電子導電剤の断面積の割合の平均値をμとし、該割合の標準偏差をσとしたとき、σ/μが、0以上、0.4以下であり、該μが、20%以上、40%以下であり、かつ、該導電層の任意の9箇所からサンプリングされる、一辺が9μmの立方体形状のサンプル立方体のうち、少なくとも8個のサンプル立方体は、下記要件(3)を満たす請求項1~7のいずれか一項に記載の現像部材:
    (3)1個のサンプル立方体を、27個の、一辺が3μmの単位立方体に区分し、該単位立方体の各々に含まれる前記ドメインの体積Vdを求めたとき、Vdが2.7μm~10.8μmである単位立方体の数が少なくとも20個であること。
    When the average value of the ratio of the cross-sectional area of the electronic conductive agent contained in each of the domains to the cross-sectional area of each of the domains appearing in the cross section in the thickness direction of the conductive layer is μ, and the standard deviation of the ratio is σ, Cubic shape in which σ / μ is 0 or more and 0.4 or less, μ is 20% or more and 40% or less, and is sampled from any nine positions of the conductive layer and has a side of 9 μm. The developing member according to any one of claims 1 to 7, wherein at least eight of the sample cubes satisfy the following requirement (3):
    (3) When one sample cube is divided into 27 unit cubes each having a side of 3 μm, and the volume Vd of the domain included in each unit cube is obtained, Vd is 2.7 μm 3 to 10 The number of unit cubes of .8 μm 3 is at least 20.
  9.  請求項1から8のいずれか一項に記載の現像部材を有することを特徴とする電子写真用のプロセスカートリッジ。 An electrophotographic process cartridge comprising the developing member according to any one of claims 1 to 8.
  10.  請求項9に記載のプロセスカートリッジを有することを特徴とする電子写真用の画像形成装置。 An image forming apparatus for electrophotography, comprising the process cartridge according to claim 9.
PCT/JP2019/016693 2018-04-18 2019-04-18 Developing member, process cartridge, and electrophotography apparatus WO2019203321A1 (en)

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US11169454B2 (en) 2019-03-29 2021-11-09 Canon Kabushiki Kaisha Electrophotographic electro-conductive member, process cartridge, and electrophotographic image forming apparatus
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US10845724B2 (en) 2019-03-29 2020-11-24 Canon Kabushiki Kaisha Electro-conductive member, process cartridge and image forming apparatus
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WO2021261216A1 (en) * 2020-06-23 2021-12-30 日本ゼオン株式会社 Acrylic rubber bale having excellent banbury processability and injection moldability

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