CN101290491A - Image forming apparatus - Google Patents
Image forming apparatus Download PDFInfo
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- CN101290491A CN101290491A CNA2008100929347A CN200810092934A CN101290491A CN 101290491 A CN101290491 A CN 101290491A CN A2008100929347 A CNA2008100929347 A CN A2008100929347A CN 200810092934 A CN200810092934 A CN 200810092934A CN 101290491 A CN101290491 A CN 101290491A
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
- G03G15/065—Arrangements for controlling the potential of the developing electrode
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
- G03G15/16—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G2215/00—Apparatus for electrophotographic processes
- G03G2215/06—Developing structures, details
- G03G2215/0602—Developer
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G2215/00—Apparatus for electrophotographic processes
- G03G2215/06—Developing structures, details
- G03G2215/0634—Developing device
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- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Developing For Electrophotography (AREA)
- Developing Agents For Electrophotography (AREA)
- Photoreceptors In Electrophotography (AREA)
Abstract
An image forming apparatus includes a photosensitive drum to which an electrostatic image is formed and a developing sleeve carrying a developer including toner carrier. An alternating voltage is applied to the sleeve to form an alternating electric field between the sleeve and the drum to develop the electrostatic image with the developer. A relation |K 1 |<|K 2 | is satisfied, where K 1 : a slope at an electric field intensity Ed=|(Vp 2 -VL)/D|, K 2 : a slope at an electric field intensity Eb=|(Vp 1 -VL)/D|, VL: a potential [V] of the electrostatic image at which a maximum density is obtained, Vp 1 : a peak potential [V] that provides a potential difference to move the toner toward the drum, Vp 2 : a peak potential [V] that provides a potential difference to move the toner toward the sleeve, and D: a closest distance [m] between the drum and the sleeve.
Description
Technical field
The present invention relates to look like to carry out visual as the static on the supporting body and obtain the image processing system such as duplicating machine, printer of image being formed on toner.More specifically, relate to the image processing system that uses 2 component developers that possess toner and carrier as developer.
Background technology
In the past, in image processing systems such as the duplicating machine that uses the electrofax mode, printer, making, exposed in this surface accordingly with image information as after charged equably as the surface of the Electrophtography photosensor (being designated hereinafter simply as " photoreceptor ") of supporting body.Thus, form static picture (sub-image) on the surface of photoreceptor.For the static picture that is formed on the photoreceptor, developer uses developer to develop as the toner picture.Toner picture on the photoreceptor directly or via the intermediate transfer body is transferred on the transfer materials.Then, by on transfer materials, making toner obtain document image as photographic fixing.
As developer, 1 component developer that is made of toner particle is in fact only generally arranged and possess toner particle and 2 component developers of carrier particle.The visualization way of using 2 component developers generally can form higher meticulous and tone preferable image aspect etc. be favourable.
It is that magnetic particle (carrier) about 5 μ m～100 μ m and particle diameter are the nonmagnetic toner about 1 μ m～10 μ m that 2 component developers generally are mixed with particle diameter with predetermined mixing ratio.Carrier plays a part the charged toner of carrying and is transported to developing parts.In addition, toner is by mixing with carrier, and by frictional electrification the predetermined carried charge of charged one-tenth predetermined polarity.
In addition, in recent years, along with the digitizing of image processing systems such as the duplicating machine of electrofax mode, printer, panchromatic (full color) change, the progress of high speed, its output image has the value as original output, and then also is worth very much expectation to entering of printing market.Therefore, requirement can be exported more high-quality (high meticulous) and the stable image of image quality.In order to obtain so high meticulous image quality, must improve development.
Usually, in using the visualization way of 2 component developers, 2 component developers that carry on the developer carrier that developer possessed be transported to photoreceptor on static as opposed developing parts.Then, 2 component developer spikes on the developer carrier are stretched out and to photoreceptor contact or approaching.Afterwards, by being applied to the predetermined development bias voltage between developer carrier and the photoreceptor, toner is transferred on the photoreceptor.Thus, on photoreceptor, form the toner picture corresponding with the static picture.
In addition, as the development bias voltage, be extensive use of the overlapping alternation bias voltage that DC voltage composition and alternating voltage component are arranged.In order to improve development, need separate more toner from carrier and develop.Therefore, need to strengthen the electric field intensity that toner is subjected to.
In order to strengthen the electric field intensity that toner is subjected to, merely strengthening the development bias voltage that is applied between developer carrier and the photoreceptor is shortcut.But, if with the development bias voltage be strengthened to required more than, then electric charge is injected into the static picture via developer carrier by carrier, makes the static image distortion sometimes.
In the past, as photoreceptor, be widely used in OPC (the organic light-guide electricity body) photoreceptor that is laminated with the charge generating layer that constitutes by organic material, charge transport layer, sealer on the metallic matrix.
On the other hand, known to form high-resolution static picture as described above, it is effective that photoreceptor is used the photoreceptor of amorphous silicon (amorphous silicon) photoreceptor individual layer series such as (hereinafter referred to as " a-Si photoreceptors ").One of its reason is as described below.
In the OPC photoreceptor, the electric charge generating mechanism of the inside of photoreceptor is present near the matrix of photoreceptor, and is relative therewith, and in the a-Si photoreceptor, the electric charge generating mechanism of the inside of photoreceptor is positioned at the surface of photoreceptor.Therefore, in the a-Si photoreceptor, the electric charge that takes place in inside can not diffuse to the surface of photoreceptor, and obtains extremely high meticulous static picture.
But it is low that a-Si photoreceptor and OPC photoreceptor are compared its surface resistance, as described abovely compares very big from developer carrier with the OPC photoreceptor via the influence that the electric charge of carrier injects.Therefore, under the situation of using the a-Si photoreceptor, the static picture of formation is distortion easily owing to electric charge injects, so further require to reduce to suppress the movement of electric charges amount as the Vpp (voltage between peak value) of the development bias voltage of alternation bias voltage.
Herein, if reduce to develop bias voltage Vpp, then inject reduction via carrier to the electric charge of photoreceptor, but the electric field that developer applies is died down from developer carrier.Therefore, the power from carrier separation toner reduces the development reduction.
On the other hand, as proposing in the Japanese kokai publication hei 8-160671 communique, form in order to carry out images with high image quality, it is effective setting the resistance of carrier higher.
But if known resistance to carrier carry out high resistanceization, then development property, the ability of promptly separating (spuing) toner from carrier reduce easily.
As mentioned above, the carrier of 2 component developers is born to developing parts and is carried the effect of toner and by frictional electrification toner is carried out the effect that electric charge is given.Therefore, carrier is endowed with the electric charge of the charged opposite polarity polarity of toner charged.For example, when the charged one-tenth negative polarity of toner, carrier is given the electric charge of positive polarity.
At this moment, if the resistance height of carrier, the electric charge of then putting aside in carrier is difficult to move, so the electric charge of the electric charge of this carrier and toner is attracted each other and produced big adhesion, toner is difficult to separate from carrier.If reduce the resistance of carrier, then the electric charge in the carrier is easily in the surface diffusion of carrier, so the adhesion of toner and carrier also diminishes, toner becomes and separates from carrier easily.
Except enhancing is applied to the method for the development bias voltage between developer carrier and the photoreceptor,, can consider to improve the specific inductive capacity of carrier herein, as the method that strengthens the electric field intensity that toner is subjected to.If increase the specific inductive capacity of carrier, split pole electric charge then by producing in carrier inside, the voltage difference of carrier inside diminishes, the electric field corresponding with this part from the carrier on sensitization side focus on and photoreceptor between air layer.Therefore, can think the electric field intensity grow that is subjected to attached to the toner on the carrier.
But, can think that if improve the specific inductive capacity of carrier the toner that then temporarily is transported on the photoreceptor also separates easily, and makes the development reduction.
As mentioned above, the development bias voltage that is applied between developer carrier and the photoreceptor uses the overlapping alternation bias voltage that DC voltage composition and alternating voltage component are arranged.That is, when applying along the direction that toner is moved to photoreceptor (hereinafter referred to as " bias voltage of development direction "), toner separates from carrier, and is transported on the photoreceptor.On the other hand, when applying the development bias voltage at switching alternation bias voltage and along the direction that toner is moved to developer carrier (hereinafter referred to as " retracting the bias voltage of direction "), toner is transferred along the developer carrier direction.
At first, under the situation of the bias voltage that applies the development direction, for the above reasons, a side of high-k carrier A compares with the low-k carrier B, and the electric field intensity that toner is subjected to uprises, and more toner is transported to photoreceptor from the carrier separation.But, apply under the situation of the bias voltage that retracts direction switching the alternation bias voltage, a side who equally also is the high-k carrier A compares with the low-k carrier B, the electric field intensity that toner is subjected to is stronger, separate more toner so cause, so produce the unreasonable situation that specific inductive capacity dies down to the influence of development from photoreceptor.
Development when Figure 15 represents to use different in the past the 2 kinds of general carriers (high-k carrier A, low-k carrier B) of specific inductive capacity characteristic poor.The transverse axis of Figure 15 voltage Vpp between the peak value of bias voltage that represents to develop, the longitudinal axis represent to be formed on the carried charge Q/S (C/cm of per unit area of the toner layer of the toner picture on the photoreceptor
2).As this Q/S (C/cm
2), the toner carrying capacity M/S (mg/cm of the per unit area of the carried charge Q/M of the per unit weight of the toner of the toner layer on the photoreceptor when use will obtain maximum concentration (μ C/g) and this toner layer
2) value after multiplying each other.Above-mentioned Q/S (C/cm
2) development capability of expression developer, promptly there are how many toners to overcome paying between carrier and the toner and put forth effort and to transfer on the photoreceptor.Maximum concentration is meant full up (solid) image color, the image color the when potential difference (PD) that is meant the image portion current potential of the flip-flop of development bias voltage and photoreceptor under the situation of discharged-area development becomes maximum.
Result when in addition, Figure 15 represents to use the OPC photoreceptor of thickness (thickness of photographic layer) 30 μ m as photoreceptor.
As can be seen from Figure 15, with the Vpp of development bias voltage irrespectively, a side of high-k carrier A compares with the low-k carrier B, Q/S (C/cm
2) higher.Fig. 4 represents the electric field interdependence of the specific inductive capacity of high-k carrier A and low-k carrier B.That is, the specific inductive capacity of carrier has the characteristic that changes accordingly with the electric field that carrier is given.As can be seen from Figure 4, the high-k carrier A is compared with the low-k carrier B when the bias voltage of development direction and when retracting the bias voltage of direction, and specific inductive capacity is all higher.But as shown in figure 15, the high-k carrier A is compared Q/S (C/cm with the low-k carrier B
2) higher reason is: the influence of electric field intensity that specific inductive capacity is carried toner to photoreceptor when the bias voltage of development direction greater than specific inductive capacity when retracting the bias voltage of direction to separate the influence of toner from photoreceptor.Therefore, because the influence of the difference of the electric field intensity that produces because of the difference of specific inductive capacity, a side of high-k carrier A compares with the low-k carrier B, the development increase.
In addition, the electrostatic capacitance of photoreceptor is also very big to the influence of development.Become big and development surpasses permissible range ground and reduces if be accompanied by the electrostatic capacitance (electrostatic capacitance of per unit area) of photoreceptor, then produce various image deflects.Then, electrostatic capacitance and the development to photoreceptor describes.
For example, consider on the OPC photoreceptor, to form the situation of the toner picture of maximum concentration with following condition.Quantity of electric charge Q/M=-30 μ C/g, the toner carrying capacity M/S=0.65mg/cm of development contrast (potential difference (PD) of the image portion current potential on the photoreceptor and the DC voltage of development bias voltage) Vcont=250V, toner
2Be made as at thickness under the situation of 30 μ m, calculate on the OPC photoreceptor current potential (charging potential) the Δ V that the toner layer by this toner picture produces according to following formula with the OPC photoreceptor.
Wherein
Q/M is the toner charge amount of the per unit weight on the photoreceptor
M/S is the toner weight of the per unit area of the maximum concentration part on the photoreceptor
λ t is the toner bed thickness of the maximum concentration part on the photoreceptor
D is the thickness of photoreceptor
ε
tRelative dielectric constant for toner layer
ε
dRelative dielectric constant for photoreceptor
ε
0Specific inductive capacity for vacuum
Under the situation of above-mentioned condition, become Δ V=243V, Vcont=250V.That is, become the state (charge efficiency 97%) that produces the current potential of static picture by the electric charge of toner layer fully.
On the other hand, the a-Si photoreceptor have relative dielectric constant than OPC photoreceptor larger about 3 times material behavior (the a-Si photoreceptor: about 10, OPC photoreceptor: about 3.3).Therefore, the a-Si photoreceptor has the electrostatic capacitance (for example 0.97 * 10 of OPC photoreceptor under the situation with the thickness equal with the OPC photoreceptor (for example 30 μ m)
-6F/m
2) about 3 times electrostatic capacitance (for example 2.95 * 10
-6F/m
2).
Consider hypothesis the Vcont same with the situation of above-mentioned OPC photoreceptor (=250V), on the a-Si photoreceptor, form the situation of the toner picture of maximum concentration under the condition of the quantity of electric charge Q/M (=-30 μ C/g) of toner.In this case, according to above-mentioned formula, satisfying the required toning dosage of Δ V=250V is 1.15mg/cm
2, the about 1.7 times toning dosage under the situation of above-mentioned OPC photoreceptor is transferred on the a-Si photoreceptor.Say that on the contrary the development contrast Vcont with about 1/1.7 can obtain toner carrying capacity M/S=0.65mg/cm
2Therefore, under the situation of a-Si photoreceptor, about Vcont=147V, just satisfy the electric charge of high concentration part.
But, for example the situation etc. that drops into light printing market in hope down, because requirement obtains wide scale grade characteristic,, be difficult to obtain high scale grade characteristic sometimes so γ characteristic (characteristic of the image color corresponding with the picture exposure) becomes sharply when Vcont=147V.That is, be difficult to reproduce the middle-bracket image of photograph image etc.
In addition, even the OPC photoreceptor also with the clear purpose that turns to of static picture, has attempted reducing the thickness (thickness of photographic layer) of photoreceptor.Under these circumstances, also further increase the electrostatic capacitance of photoreceptor, so produce sometimes and the same problem of situation that above-mentioned a-Si photoreceptor is illustrated by the thickness that reduces photoreceptor.
Little and the problem that causes of thickness big for the relative dielectric constant of dealing with such photoreceptor or photoreceptor can consider to improve the Q/S (C/cm of the toner layer of toner picture
2), promptly improve the method for the carried charge Q/M (μ C/g) of toner.For example, with respect to above-mentioned-30 μ c/g, toner carried charge Q/M (μ C/g) is made as-60 μ C/g.Under this state, for example, when development contrast Vcont is 240V, if can be with toner carrying capacity M/S (mg/cm
2) be taken as 0.65mg/cm
2, the Δ V that then toner layer produced is 238V (that is, about 240V), charge efficiency is approximately 100%.
But in fact, if improve the carried charge Q/M (μ C/g) of developer, then the electrostatic force of carrier and toner becomes very big, so development property significantly reduces sometimes.
As described above, for example under the situation of the photoreceptor that surface resistance is low as the a-Si photoreceptor, owing to when developing, looking like to prevent that at static electric charge from injecting, so can't increase the Vpp of development bias voltage.On the other hand, for a-Si photoreceptor or the such big photoreceptor of electrostatic capacitance of film OPC photoreceptor, image deflects such as hickie can not take place in the method that improves the carried charge Q/M (μ C/g) of toner, and become the effective ways of stablizing and obtaining sufficient scale grade characteristic.But if improve the carried charge Q/M (μ C/g) of toner, then development property significantly reduces sometimes.
Summary of the invention
The objective of the invention is to: the image processing system that provides a kind of use to possess 2 component developers of toner and carrier, this image processing system can suppress via carrier to obtain good development when the electric charge of static picture injects.
Other purposes of the present invention are: a kind of image processing system is provided, and it has the developing apparatus that uses the carrier of high-k and increase substantially the visualization way of development when developing.
Other purposes of the present invention are: provide a kind of image processing system, even it has the developing apparatus that also can increase substantially the visualization way of development under the situation of using the high toner of carried charge.
Other purposes of the present invention are: even a kind of image processing system that also can form the meticulous and stable image of height under the situation of using the big photoreceptor of electrostatic capacitance for a long time is provided.
Other purposes of the present invention are: the image processing system that the variation corresponding vectors resistance characteristic of the electric field between a kind of suitably setting and picture supporting body and the developer carrier is provided.
Describe in detail by the reference accompanying drawing and below reading, with clear and definite more purpose of the present invention and feature.
Description of drawings
Fig. 1 is the summary sectional structure chart of an embodiment of explanation image processing system of the present invention.
Fig. 2 is the synoptic diagram of an embodiment that is used to illustrate the layer structure of photoreceptor.
Fig. 3 A, 3B, 3C, 3D are the synoptic diagram of other embodiment that is used to illustrate the layer structure of photoreceptor.
Fig. 4 is the curve map that is used for illustrating the specific inductive capacity change of the carrier that applies the development bias voltage.
Fig. 5 is the synoptic diagram of assay method that is used to illustrate the specific inductive capacity of carrier.
Fig. 6 is the key diagram of relation that is used to illustrate the current potential of development bias voltage and static picture.
Fig. 7 is the key diagram of relation that is used to illustrate the current potential of development bias voltage and static picture.
Fig. 8 is the curve map that is used for illustrating the specific inductive capacity change of the carrier that applies the development bias voltage.
Fig. 9 is used to illustrate with the bias voltage time down of developing change the figure chart that the specific inductive capacity of corresponding vectors changes.
Figure 10 is the curve map that is used for illustrating the specific inductive capacity change of the carrier that applies the development bias voltage.
Figure 11 is the curve map that is used for illustrating the specific inductive capacity change of the carrier that applies the development bias voltage.
Figure 12 A and Figure 12 B are used to illustrate figure chart under the development bias voltage and specific inductive capacity change time variation corresponding vectors.
Figure 13 is the key diagram of relation that is used for illustrating the current potential of the development bias voltage of concrete example and static picture.
Figure 14 is the key diagram of relation that is used for illustrating the current potential of the development bias voltage of concrete example and static picture.
Figure 15 is the curve map that is used to illustrate the difference of the development that produces because of carrier.
Embodiment
Below, illustrate in greater detail image processing system of the present invention with reference to the accompanying drawings.
(image processing system)
Fig. 1 represents the summary cross-section structure of major part of the image processing system 100 of one embodiment of the present of invention.
As photoreceptor 1, can use general conduct have at least the organic light-guide electrics layer photoreceptor the OPC photoreceptor and as the a-Si photoreceptor that has the photoreceptor of amorphous silicon layer at least.
The OPC photoreceptor is formed with on conductive base that to possess with organic light-guide electricity body be the photographic layer (light-sensitive surface) of the optical conductive layer of major component.The OPC photoreceptor constitutes and be laminated with charge generating layer 12, charge transport layer 13 and the sealer 14 that is made of organic material on metallic matrix 11 generally as shown in Figure 2.
In addition, the a-Si photoreceptor has on conductive base that to possess with amorphous silicon (amorphous silicon) be the photographic layer (light-sensitive surface) of the optical conductive layer of major component.As the a-Si photoreceptor, the photoreceptor of following layer structure is like that arranged generally.
That is, the a-Si photoreceptor is provided with light-sensitive surface 22 at photoreceptor on support (matrix) 21 as shown in Figure 3A like that.In the present example, this light-sensitive surface 22 is made of the optical conductive layer with photoconductivity 23 that forms with a-Si:H, X (H is a hydrogen atom, and X is a halogen atom).
A-Si photoreceptor shown in Fig. 3 B is provided with light-sensitive surface 22 at photoreceptor on support 21.This light-sensitive surface 22 is made of optical conductive layer with photoconductivity 23 that becomes with a-Si:X, X-shaped and amorphous layer tabulation surface layer 24.
A-Si photoreceptor shown in Fig. 3 C is provided with light-sensitive surface 22 at photoreceptor on support 21.This light-sensitive surface 22 injects trapping layer 25 by the optical conductive layer with photoconductivity 23 that becomes with a-Si:H, X-shaped, amorphous layer tabulation surface layer 24 and amorphous silicon series electric charge and constitutes.
A-Si photoreceptor shown in Fig. 3 D is provided with light-sensitive surface 22 at photoreceptor on support 21.This light-sensitive surface 22 is made of the charge generating layer 26 that becomes with the a-Si:H that constitutes optical conductive layer 23, X-shaped and charge transport layer 27 and amorphous layer tabulation surface layer 24.In order to have that the surface is difficult to cut and the feature of high-durability and use the advantage of a-Si photoreceptor very big.
In addition,, be not limited to layer structure as described above, also can use the photoreceptor of other layer structure as photoreceptor 1.
In Fig. 1, rotate driving photoreceptor 1 with predetermined peripheral speed along the arrow A direction of Fig. 1.The surface of the photoreceptor 1 of rotation is roughly charged equably by charged device 2.And, with exposer 3 opposed positions, irradiate the laser luminous accordingly from exposer 3 with picture signal, on photoreceptor 1, form the static picture corresponding with original image.
If the rotation of static picture by photoreceptor 1 that is formed on the photoreceptor 1 arrives and developer 4 opposed positions, then utilize 2 component developers that possess nonmagnetic toner particle (toner) T and magnetic carrier particle (carrier) C in the developer 4 and develop to the toner picture.In fact only form the toner picture by the toner in 2 component developers.
Developer 4 has the developer container (developer main body) 44 of accommodating 2 component developers.In addition, developer container 4 has the development sleeve 41 as developer carrier.Development sleeve 41 can be configured in the peristome 44a of developer container 44 rotatably, and, contain magnet 42 as the roll profile of field generating unit in inside.
In the present embodiment, development sleeve 41 be driven in rotation into its surface along with photoreceptor 1 opposed opposed portion, be that the direction that the surperficial moving direction of photoreceptor 1 is identical among the developing parts G (B direction) moves.2 component developers on the surface that is carried to development sleeve 41 after, control by 43 pairs of amounts of limiting member, and be transported to and photoreceptor 1 opposed developing parts G.
The following effect of support C performance: carry charged toner and be transported to developing parts G.In addition, toner T is by mixing with support C, and by frictional electrification the predetermined carried charge of charged one-tenth predetermined polarity.2 component developers on the development sleeve 41 are in developing parts G, by magnetic field that magnet 42 produced and spike is stretched out the formation magnetic brush.And, in the present embodiment, this magnetic brush is contacted with the surface of photoreceptor 1, perhaps apply predetermined development bias voltage, thereby only make toner T transfer to static picture on the photoreceptor 1 from 2 component developers to development sleeve 41.
The toner picture that is formed on the photoreceptor 1 is transferred on the transfer materials P statically by transfer belt electrical equipment 5.Then, transfer materials P is transported to fuser 6, heats, pressurizes at this, thereby in its surface toner T is carried out photographic fixing.Then, transfer materials P is discharged to outside the device as output image.
In addition, be removed by washer 7 at the toner T that remains in behind the transfer printing process on the photoreceptor 1.Then, by the photoreceptor 1 after washer 7 cleaning by from the rayed of prior exposure device 8 by electric initialization, repeat above-mentioned image thus and form action.
(specific inductive capacity of carrier)
As mentioned above, possess in the image processing system of 2 component developers of toner T and support C, it is desirable to as follows in use.
That is, the electric charge to the static picture in order to prevent to develop injects, and voltage Vpp between the peak value of development bias voltage is improved too many.In addition, when for corresponding to use in the present embodiment such, for example more than or equal to 1.7 * 10
-6F/m
2The big photoreceptor (amorphous silicon photoreceptor body) of electrostatic capacitance and when need improving the carried charge of toner, the development capability that also should not make toner produce the current potential of static picture reduces.
And, as its method, can consider to strengthen the actual electrical field strength that toner is subjected to.
Therefore, one object of the present invention is: even propose a kind of visualization way that also can increase substantially development under the situation of using the high toner of carried charge.In addition, another object of the present invention is to:, also can form high meticulous and stable image for a long time even under the situation of using the big photoreceptor of electrostatic capacitance.
Therefore, in the present invention, suitably set the electric field interdependence of the specific inductive capacity of the carrier under the development bias voltage.Below, be described in detail.
Fig. 4 represents the electric field interdependence of the relative dielectric constant ε of 2 kinds of general carriers (high-k carrier A, low-k carrier B) in the past that electric specific inductive capacity characteristic is different.The transverse axis of Fig. 4 is represented electric field intensity [V/m], and the longitudinal axis is represented relative dielectric constant ε.Relative dielectric constant represents that by the specific inductive capacity of specific inductive capacity/vacuum the specific inductive capacity of vacuum is 8.854 * 10
-12F/m, relative dielectric constant are the value corresponding with specific inductive capacity.
Can use as shown in Figure 5 device to measure the relative dielectric constant of carrier.
That is, the development sleeve 41 that makes the developer 4 that only contains carrier and cylinder (hereinafter referred to as " aluminium drum (Aluminum Drum) ") Dr with the aluminum of predetermined peripheral speed (the surperficial translational speed of common photoreceptor) rotation only leave predetermined distance (closest-approach distance during common development) D and opposed.Then, Yi Bian make development sleeve 41, utilize power supply HV (NF corporate system, HVA 4321) between bulging Dr of aluminium and development sleeve 41, to apply AC voltage (Sin ripple) on one side with predetermined peripheral speed (peripheral speed during common development) rotation.At this moment, the Sin wave frequency is scanned (Sweep), and to apply voltage corresponding response electric current and carry out instrumentation, thereby can determine impedance.In the present example, utilize the dielectric of Britain ソ one ラ ト Application corporate system to measure the impedance that system 5 (126096W) automatically measures carrier.In Fig. 5, represent impedance measuring instrument with Z.Calculate the electrostatic capacitance of carrier according to the impedometer that determines,,, calculate the specific inductive capacity of carrier according to the contact area of the distance between development sleeve 41 and the aluminium drum, carrier and aluminium drum with respect to the electrostatic capacitance that calculates.In addition, by the Sin wave amplitude that applies is scanned the electric field interdependence that (Sweep) measures the relative dielectric constant of carrier.
In addition, the electric field strength E that the electric field intensity of the transverse axis of Fig. 4 [V/m] is located for the approximated position (closest-approach distance D) of aluminium drum Dr and development sleeve 41 is obtained the voltage that applies between aluminium drum Dr and the development sleeve 41 divided by distance D.
In Fig. 4, the line of representing with solid line is the electric field interdependence of the specific inductive capacity of high-k carrier A, and the line that dots is the electric field interdependence of the specific inductive capacity of low-k carrier B.
As can be seen from Figure 4, a side of high-k carrier A compares with the low-k carrier B, and the slope of the relative dielectric constant corresponding with its electric field intensity is bigger.
In addition, high-k carrier A and low-k carrier B be meant in Fig. 4 when electric field intensity from the E1 change during for E2, its relative dielectric constant ε is,
The high-k carrier A: vary to ε A2=43 from ε A1=12,
Low-k carrier B: vary to ε B2=10 from ε B1=7.
The current potential of the static picture on the photoreceptor 1 when Fig. 6 represents developing operation and the development bias voltage that development sleeve 41 is applied.The transverse axis express time of Fig. 6, the longitudinal axis is represented current potential.
In the present embodiment, as the development bias voltage, use the development bias voltage (alternation bias voltage) of general square wave.This development bias voltage is to overlap onto development bias voltage in the alternating voltage component (voltage Vpp between peak value: spike potential Vp1, Vp2) with the DC voltage composition (Vdc) that Vdc represents.This development bias voltage is applied between the static picture and development sleeve 41 of photoreceptor 1.
In addition, in the present embodiment, suppose that the image exposure mode that forms the static picture by image portion is exposed forms static and looks like to describe.That is, in the dark portion and highlights of static picture, image portion becomes highlights.In addition, in the present embodiment, suppose that photoreceptor 1 charged one-tenth negative polarity describes.In addition, in the present embodiment, toner becomes negative polarity by charged with the frictional electrification of carrier, as visualization way, suppose to use the discharged-area development mode describe, this discharged-area development mode is used the toner (the image portion that has been exposed on the photoreceptor is developed) of the frictional electrification one-tenth polarity identical with the charged polarity of photoreceptor.
In Fig. 6, VD is the charged current potential (dark portion current potential) of photoreceptor 1, in the present embodiment, and by charged elements 2 charged one-tenth negative polarity.In Fig. 6, VL be the zone of the image portion that exposed by exposing unit 3 current potential, be the highlights current potential, become the current potential that is used to obtain maximum concentration.That is, VL current potential portion is the maximum zone of adhesion amount of toner.
Herein, if change with respect to the timeliness of VL current potential with reference to Fig. 6 and Fig. 7 bias voltage of considering to develop, then electric field strength E a, Eb, Ec, Ed, the Ee of each time point of a, the b that comes to represent in the presentation graphs 7 with following formula respectively, c, d, e.
Ea＝Ec＝Ee＝|(Vdc-VL)/D|
Eb＝|(Vp1-VL)/D|
Ed＝|(Vp2-VL)/D|
(herein,
VL is the current potential " V " that is used to obtain the static picture of maximum concentration,
Vp1 be in the spike potential of alternation bias voltage, make toner move the spike potential " V " of such potential difference (PD) with respect to the part setting of VL current potential to photoreceptor,
Vp2 be in the spike potential of alternation bias voltage, make toner move the spike potential " V " of such potential difference (PD) with respect to the setting of VL current potential to development sleeve,
Vdc is the Dc bias composition " V " of development bias voltage,
D is the closest-approach distance " m " between photoreceptor 1 and the development sleeve 41)
In addition, represent Vp1, Vp2 with following formula accordingly with the charged polarity of toner.
Toner is-situation of polarity: Vp1=Vdc-|Vpp/2|
Toner is+situation of polarity: Vp1=Vdc+|Vpp/2|
Toner is-situation of polarity: Vp2=Vdc+|Vpp/2|
Toner is+situation of polarity: Vp2=Vdc-|Vpp/2|
(wherein, Vpp is a voltage " V " between the peak value of alternation bias voltage,
Vdc is the Dc bias composition " V " of development bias voltage)
That is, electric field strength E a, Ec and Ee obtain the distance D of the potential difference (PD) between the current potential (VL current potential) of the maximum concentration portion of the Dc bias of development bias voltage and the static picture on the photoreceptor 1 divided by the place, approximated position of photoreceptor 1 and development sleeve 41.Electric field strength E b (development electric field intensity) with and photoreceptor 1 on the VL current potential between the spike potential of the potential difference (PD) that forms electric field from a side to photoreceptor 1 that make toner move and the potential difference (PD) between the VL current potential on the photoreceptor 1 be set obtain divided by the closest-approach distance D of photoreceptor 1 and development sleeve 41.In addition, electric field strength E d (retracting electric field intensity) with and photoreceptor 1 on the VL current potential between the spike potential of the potential difference (PD) that forms electric field from a side to development sleeve 41 that make toner move and the potential difference (PD) between the VL current potential be set obtain divided by the closest-approach distance D of photoreceptor 1 and development sleeve 41.
On the other hand, as reference Fig. 4 was illustrated, the specific inductive capacity of carrier had the electric field interdependence.Therefore, as using shown in the arrow among Fig. 8, under the development bias voltage, change as Ea → Eb → Ec → Ed → Ee corresponding to electric field intensity, the relative dielectric constant of carrier changes.
Therefore, for example under the situation of high-k carrier A, its relative dielectric constant changes as ε 1 → ε 3 → ε 1 → ε 2 → ε 1, and under the situation of low-k carrier B, its relative dielectric constant changes as ε 4 → ε 6 → ε 4 → ε 5 → ε 4.If with respect to the time variation variation of this relative dielectric constant is drawn, then as shown in Figure 9.
That is, under the situation of high-k carrier A, the specific inductive capacity of the carrier when applying the development electric field becomes than higher relative dielectric constant ε 3.Relative therewith, under the situation of low-k carrier B, the specific inductive capacity of the carrier when applying the development electric field is lower relative dielectric constant ε about 6.That is, the increment rate of the specific inductive capacity of the carrier when applying the development electric field is in the low-k carrier B, and is little than the high-k carrier A.It is poor that its poor voltage that becomes carrier inside descends, and becomes the poor of development.
Herein, Figure 10 represents the electric field interdependence of specific inductive capacity of the support C (being designated hereinafter simply as " support C ") of present embodiment.
As learning from Figure 10, with the situation of high-k carrier A, low-k carrier B similarly, the specific inductive capacity of support C has the electric field interdependence, but under the situation of support C, has the characteristic (flex point P) that the slope of the electric field interdependence of its specific inductive capacity under predetermined electric field strength E p becomes precipitous.
Promptly, for support C, its DIELECTRIC CONSTANT has slope (Δ ε/Δ E) with respect to the variation of the electric field strength E (=Δ V/D) of the value that obtains divided by the closest-approach distance D of photoreceptor 1 and development sleeve 41 as the potential difference (PD) Δ V with the current potential of the current potential of development sleeve 41 and the static picture on the photoreceptor 1.And support C is under the electric field strength E p that the relation of Ed＜Ep＜Eb is set up, and the slope of the electric field interdependence of DIELECTRIC CONSTANT (Δ ε/Δ E) changes.
And, as shown in figure 10, for support C, the slope (Δ ε/Δ E) of the electric field interdependence of the DIELECTRIC CONSTANT under the electric field intensity X that the relation of X＜Ep is set up is made as K1, and the slope (Δ ε/Δ E) of the electric field interdependence of the DIELECTRIC CONSTANT among the electric field intensity Y that the relation of Y＞Ep is set up is made as under the situation of K2, | K1|＜| K2| sets up.In addition, the slope of the specific inductive capacity under the electric field strength E d is K1, and the slope of the specific inductive capacity under the electric field strength E b is K2.Therefore, the slope of the specific inductive capacity under the electric field strength E b | K2| is greater than the slope of the specific inductive capacity under the dielectric strength Ed | K1|.
As shown in figure 10, if support C is subjected to development bias voltage as described above, then change as Ea → Eb → Ec → Ed → Ee corresponding to electric field intensity, the relative dielectric constant of carrier changes as ε 7 → ε 9 → ε 7 → ε 8 → ε 7.
If with respect to the time variation variation of the specific inductive capacity of this support C is drawn, then shown in Figure 12 B.The variation (equal) of the specific inductive capacity of expression carrier A and carrier B in Figure 12 A with Fig. 9.
That is, the specific inductive capacity of support C apply development electric field (electric field strength E b) during become higher relative dielectric constant ε 9, on the contrary apply retract electric field (electric field strength E d) during keep lower relative dielectric constant ε 8.
Only when having formed development electric field Eb, its specific inductive capacity increases support C sharp, reduces because the voltage of the carrier inside that the carrier split pole produces descends, so the electric field grow that produces around carrier, that is, the actual electric field that toner is subjected to increases.Therefore, compare with the low-k carrier B, toner separates from carrier easily.
On the other hand, forming when retracting electric field Ed, the specific inductive capacity step-down of carrier becomes big so the voltage of carrier inside descends, and the electric field that produces around carrier dies down.Therefore, applying under the situation that retracts electric field, comparing with the high-k carrier A, toner is withdrawn into carrier once more from photoreceptor 1, and bound chance also tails off.
Like this, in support C, only specific inductive capacity uprises when being applied in development electric field Eb, guarantees development property as the high-k carrier A, being applied in when retracting electric field Rd, keeps low-k on the contrary, and back edge dies down.Its result compares with high-k carrier A and low-k carrier B, and development property uprises generally.Like this as support C, the slope K 2 with the specific inductive capacity under the electric field strength E b is important greater than the characteristic of the slope K 1 of the specific inductive capacity under the electric field strength E d.
More than, the specific inductive capacity characteristic of support C schematically has been described.By having the such electric specific inductive capacity characteristic of above-mentioned support C, compare with the situation of using high-k carrier A and low-k carrier B, can increase substantially development.That is, the carrier by use has structure as described above can increase substantially the development of the high toner of carried charge, even the big photoreceptor of electrostatic capacitance also can form high meticulous and stable image for a long time.
According to present inventors' research, general, the a-Si photoreceptor has more than or equal to 1.7 * 10
-6F/m
2Electrostatic capacitance, in addition, even in the thin OPC photoreceptor of Film Thickness Ratio, also can have above-mentioned electrostatic capacitance.Usually, the thickness of OPC photoreceptor is more than or equal to 20 μ m, so the electrostatic capacitance of per unit area is smaller or equal to 1.7 * 10
-6F/m
2
In addition, can the following electrostatic capacitance of obtaining the per unit area of photoreceptor 1 like that.
C＝(εo×εd)/d
C: electrostatic capacitance
ε o: the specific inductive capacity of vacuum
ε d: the specific inductive capacity of photoreceptor
D: the thickness of photoreceptor
According to present inventors' research, known the present invention in the electrostatic capacitance of the per unit area of photoreceptor 1 more than or equal to 1.7 * 10
-6F/m
2Situation under be extremely effective.In addition, for the hickie image on the image-region that reduces maximum concentration and border of middle-bracket image-region etc., it is important utilizing the electric charge of toner to apply current potential fully with respect to the sub-image current potential.That is, charging potential Δ V but in order to reduce the hickie image, it is desirable to charge efficiency (%)=(charging potential Δ V/ development contrast Vcont) * 100 more than or equal to 90% as the formula (1).
Below, specifically enumerate high-k carrier A, low-k carrier B, support C of the present invention feature separately.
The high-k carrier A
As the high-k carrier A, for example can enumerate as core material and use the magnet with the magnetic by following formula (1) or (2) expression and the carrier of ferrite (ferrite).
MO·Fe
2O
3......(1)
M·Fe
2O
4......(2)
(in the formula, M represents the metallic ion of 3 valencys, divalent or 1 valency.)
As M, can enumerate Be, Mg, Ca, Rb, Sr, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Cd, Pb and Li, they can use separately, perhaps use a plurality of.
As above-mentioned particular compound, for example, can enumerate Cu-Zn-Fe based ferrite, Mn-Mg-Fe based ferrite, Mn-Mg-Sr-Fe based ferrite and the such ferrous oxide of Li-Fe based ferrite with metallic compound particle of magnetic.
As the manufacture method of ferrite particle, can adopt known method.For example, can enumerate following such method.That is, in chippy ferrite composite, mixed adhesive (binder), water, spreading agent, organic solvent etc. use spray drying process (spray dry) or fluidized granulation method to form particle.Then, use rotary kiln (Rotary Kiln) or batch-type incinerator under 700～1400 ℃, the temperature of preferred 800～1300 ℃ scope, to burn.Then, carry out sieve classification and control size-grade distribution, and become the core material particle that carrier is used.And then, on the ferrite particle surface, by the resins such as silicones about infusion process coating 0.1～1.0 quality %.
The carrier of making like this is called the high-k carrier A herein.
The low-k carrier B
As the low-k carrier B, for example, can enumerate following such carrier.The 1st, magnet particle and thermoplastic resin are carried out the fusion stirring, the magnetic dispersion type resin carrier that pulverizing is made is as core material.The 2nd, will carry out magnetic dispersion type resin carrier that spray drying makes by the slurries (slurry) that spray dryer etc. is dispersed with magnet particle and thermoplastic resin to fusion in solvent as core material.The 3rd, will be under the situation that has magnet particle and hematite (hematite) particle react the magnetic dispersion type resin carrier that has hardened and be used as core material by directly overlapping phenol (phenol).On the core material of above-mentioned carrier, further pass through fluidized bed applying device etc., the resins such as thermoplastic resin about coating 1.0～4.0 quality %.
The carrier of making like this is called the low-k carrier B herein.
Support C of the present invention:
On the other hand,, for example can use resin such as silicones to flow into the core of vesicular (porous), fill the vesicular resin in the space of in-core with resin and filled carrier as support C of the present invention.
As the manufacture method of this support C, can enumerate following such method.What at first, weighing went out scheduled volume is used for the such metal oxide of above-mentioned high-k carrier A, iron oxide (Fe
2O
3) and additive, and mix.As above-mentioned additive, can enumerate the oxide more than a kind, for example BaO, the Al of the element of IA, the IIA, IIIA, IVA, VA, IIIB and the VB family that belong to periodic table
2O
3, TiO
2, SiO
2, SnO
2And Bi
2O
5Deng.Then, in 700～1000 ℃ scope, the potpourri of obtaining was calcined 5 hours, then, be ground into the particle diameter about 0.3～3 μ m.As required the crushed material of obtaining is added bonding agent and gas-development agent, under 100 ℃～200 ℃ heating atmosphere gas, carry out spray drying, be a granulated into the size about 20～50 μ m.Then, at oxygen concentration smaller or equal to 5% inert gas (for example, N
2Gas etc.) under the atmosphere gas, 1000～1400 ℃ of following calcinations of sintering temperature 8～12 hours.Obtain cavernous core thus.Then, by the silicones of infusion process filling 8～15 quality %, under 180～200 ℃ of atmosphere of inert gases gas, make this silicones sclerosis.
In above-mentioned method for making, electric field interdependence for the specific inductive capacity of carrier, by the amount of resin of the vesicularity of core, the resistance of core itself and the silicones of filling etc. is controlled, can control flex point, slope K 1, K2, the specific inductive capacity when applying electric field Eb, Ed etc.
By above-mentioned parameter is controlled, can make insulation division and conductive part be mixed into the state of expectation in the inside of support C, can control the quantity of electric charge that flows through carrier.
For example, under the situation of the carrier that core as the high-k carrier A is all formed by the material of electric conductivity, when applying the development bias voltage, be easy to generate power path in carrier and between carrier, resistance value reduces sharp.But,,, stoped flowing of electric charge in a way in this resin part owing in the inside of support C of the present invention, filled resin to the space of vesicular core.
Therefore, when being applied in the development bias voltage, do not produce rapid specific inductive capacity, and can under the electric field intensity of expectation, make change in dielectric constant.
Then, concrete example of the present invention is described.
(concrete example)
A concrete example of the current potential of static picture when Figure 13 represents actual developing operation, on the photoreceptor 1 and development bias voltage that development sleeve 41 is applied.The transverse axis express time of Figure 13, the longitudinal axis is represented current potential.
In this concrete example,, use the development bias voltage (alternation bias voltage) of the square wave of Vpp=1.8kV, DC voltage composition Vdc=-350V, frequency f=12KHz (1 cycles 83.3 μ sec) as the development bias voltage.This development bias voltage is applied between the static picture and development sleeve 41 of photoreceptor 1.
In this concrete example, form the static picture in the image exposure mode.In addition, in this concrete example, developer becomes negative polarity by charged with the frictional electrification of carrier, as visualization way, uses the discharged-area development mode.
In Figure 13, VD is the charged current potential of photoreceptor 1, in this concrete example, by charged device 2 charged one-tenth-500V.In Figure 13, VL is the zone of the image portion that exposed by exposer 3, set for as the current potential that is used to obtain maximum concentration-100V.
If change with respect to the timeliness of VL current potential with reference to Figure 14 bias voltage of considering to develop, then calculate electric field strength E a, Eb, Ec, Ed, the Ee of each time point of a, b, c, d, e respectively with following formula.
In addition, set the closest-approach distance D between photoreceptor 1 and the development sleeve 41 for 300 μ m.
Ea＝Ec＝Ee＝|(Vdc-VL)/D|＝0.83×10
6V/m
Eb＝|(Vp1-VL)/D|＝3.8×10
6V/m
Ed＝|(Vp2-VL)/D|＝2.2×10
6V/m
Therefore, shown in Figure 12 A, 12B, if with respect to the time variation variation of the specific inductive capacity of the carrier under the development bias voltage is drawn, then the specific inductive capacity of high-k carrier A and low-k carrier B and support C of the present invention is as described below.
High-k carrier A: ε 1=15, ε 2=26, ε 3=40
Low-k carrier B: ε 4=7, ε 5=8, ε 6=9
Support C of the present invention: ε 7=9, ε 8=12, ε 9=30
Specific inductive capacity to each carrier compares.At first, if the specific inductive capacity under the observation development electric field Eb, then the DIELECTRIC CONSTANT 3 of high-k carrier A is the highest, follows the ε 6 for the DIELECTRIC CONSTANT 9 of support C of the present invention, low-k carrier.Therefore, for the electric field that toner is separated from carrier, the high-k carrier A is the strongest, then is the order of support C of the present invention, low-k carrier B.
Then, compare retracting electric field.Specific inductive capacity when retracting electric field Ed also is that the DIELECTRIC CONSTANT 2 of high-k carrier A is the highest.Follow ε 5 for the DIELECTRIC CONSTANT 8 of support C of the present invention, low-k carrier.Therefore, for the electric field that retracts toner, also be that the high-k carrier A is the highest, low-k carrier B and support C of the present invention are low.
In order to improve development, and separate more toner from carrier, the practice that reduces the toner that is pulled is effective.Under the situation of high-k carrier A, the electric-field strength that toner is developed, but it is equally also strong to retract electric field.The Q/S of expression development becomes 27 * 10
-3(μ C/cm
2).For the low-k carrier B, retract a little less than the electric field, but the electric field that develops also a little less than, so development is low, Q/S becomes 23 * 10
-3(μ C/cm
2).For support C of the present invention, the electric-field strength that toner is developed, and retract a little less than the electric field, so can obtain high development, Q/S becomes 35 * 10
-3(μ C/cm
2).
In addition, according to other concrete examples, for example, under the situation of Vpp=1.3kV, become development electric field Eb=3.0 * 10
6V/m, retract electric field Ed=1.3 * 10
6V/m.
Development electric field Eb=3.0 * 10 under the situation of Vpp=1.3kV
6V/m and retract electric field Ed=1.3 * 10
6Under the V/m, in support C of the present invention, do not present and be used to obtain than high-k carrier A and the higher Q/S (C/cm of low-k carrier B
2) specific inductive capacity.Therefore, be the method for making same though use with support C of the present invention, by change calcination temperature, heating atmosphere gas the carrier D of the variations such as amount of resin of the vesicularity of core, the resistance of core itself and the silicones of filling etc. is compared.
Figure 11 represents the electric field interdependence of the specific inductive capacity of carrier D of the present invention.As can be seen from Figure 11, carrier D compares with support C, and the slope of specific inductive capacity changes under lower electric field.In addition, the specific inductive capacity of carrier D also with support C similarly, be applied in development electric field (electric field strength E b) during, become higher relative dielectric constant ε 12, on the contrary be applied in retract electric field (electric field strength E d) during, keep lower relative dielectric constant ε 11.
Under the situation of Vpp=1.3kV, development electric field Eb=3.0 * 10
6V/m, retract electric field Ed=1.3 * 10
6Under the V/m, the specific inductive capacity of high-k carrier A and low-k carrier B and carrier D of the present invention is as described below.
High-k carrier A: ε 1=15, ε 2=19, ε 3=33
Low-k carrier B: ε 4=7, ε 5=7, ε 6=8
Carrier D of the present invention: ε 10=8, ε 11=10, ε 12=29
Wherein, become ε 4=ε 5 in the low-k carrier B, but this is to be respectively first value that rounds up of radix point to the ε 4 and the ε 5 of reality, in fact ε 4＜ε 5.That is, in Figure 11 from electric field strength E a, Ec, Ee to the Ed, the specific inductive capacity of low-k carrier B has slope.
Under Vpp=1.3kV, also with Vpp=1.8kV similarly, under the situation of high-k carrier A, the electric-field strength that toner is developed, but it is strong similarly to retract electric field, so be not so high as development, Q/S becomes 22 * 10
-3(μ C/cm
2).For the low-k carrier B, retract a little less than the electric field, but the electric field that develops also a little less than, so development is low, Q/S is 21 * 10
-3(μ C/cm
2).On the other hand, for carrier D, the electric-field strength that toner is developed, and retract a little less than the electric field, so can obtain Q/S=7 * 10
-3(μ C/cm
2) the height development.
Therefore, the amount of resin by the vesicularity that changes core, the resistance of core itself and the silicones of filling etc. etc. can improve development in the electric field of wide region.
As mentioned above, by reducing Vpp, the electric charge in the time of can preventing to develop injects, but can weaken corresponding with this part the electric field intensity that toner is developed of being used on the contrary, so development itself is brought influence.Therefore, do not wish to reduce without end Vpp.
According to the result of present inventors' research, suitable Vpp can put forth effort to change according to paying of selected toner and carrier, but is preferably
1.6×10
6V/m＜Eb＜3.9×10
6V/m
1.6×10
5V/m＜Ed＜2.5×10
6V/m
In addition, Eb is greater than Ed.
More than, according to specific embodiment the present invention has been described, but has been appreciated that to the present invention and is not limited to the above embodiments and concrete example.
For example, in the foregoing description and concrete example, the charged one-tenth negative polarity of photoreceptor has been described, on photoreceptor, has formed the static picture by the image exposure mode.But the present invention is not limited to this, and the charged polarity of photoreceptor also can be positive polarity.In addition, also can utilize the background Exposure mode that exposes and form the static picture by the non-image portion that should not adhere to toner, on photoreceptor, form the static picture.In addition, as visualization way, also can use the normal development mode, this normal development mode is used the toner (the image portion that does not have exposure to photoreceptor develops) of the charged opposite polarity polarity of charged one-tenth and photoreceptor.
According to the present invention, possess in the image processing system of 2 component developers of toner and carrier in use, can suppress via carrier when the electric charge of static picture injects, to obtain good development.
Claims (5)
1. image processing system is characterized in that comprising:
The picture supporting body; And
Carrying possesses the developer carrier of the developer of toner and carrier, above-mentioned developer carrier uses above-mentioned developer above-mentionedly to look like to develop as the static on the supporting body to being formed on, in order to form alternating electric field between above-mentioned developer carrier and above-mentioned picture supporting body, above-mentioned developer carrier is applied in alternating voltage;
To be made as transverse axis to the electric field intensity that above-mentioned carrier applies, the specific inductive capacity of above-mentioned carrier be made as in the curve map of the longitudinal axis,
If establishing the slope of electric field strength E d=| (Vp2-VL)/D| is K1,
If the slope of electric field strength E b=| (Vp1-VL)/D| is K2,
Then | K1|＜| the relation of K2| is set up, wherein,
VL is the current potential " V " that is used to obtain the above-mentioned static picture of maximum concentration,
Vp1 be in the spike potential of above-mentioned alternating voltage, make the spike potential " V " of toner with respect to the part setting of above-mentioned VL to above-mentioned potential difference (PD) as supporting body moves,
Vp2 be in the spike potential of above-mentioned alternating voltage, make toner move the spike potential " V " of such potential difference (PD) with respect to the setting of above-mentioned VL current potential to above-mentioned developer carrier,
D is the closest-approach distance " m " between above-mentioned picture supporting body and the above-mentioned developer carrier.
2. image processing system according to claim 1 is characterized in that:
The scope of above-mentioned electric field strength E b and Ed satisfies following relation:
1.6×10
6V/m＜Eb＜3.9×10
6V/m，
1.6×10
5V/m＜Ed＜2.5×10
6V/m。
3. image processing system according to claim 1 is characterized in that:
The electrostatic capacitance of above-mentioned picture supporting body is more than or equal to 1.7 * 10
-6F/m
2
4. image processing system according to claim 1 is characterized in that:
Above-mentioned picture supporting body is a photoreceptor, and this photoreceptor possesses amorphous silicon layer.
5. image processing system according to claim 1 is characterized in that:
Above-mentioned picture supporting body is a photoreceptor, and this photoreceptor possesses the organic light-guide electrics layer.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007-112424 | 2007-04-20 | ||
| JP2007112424 | 2007-04-20 | ||
| JP2008-105178 | 2008-04-14 | ||
| JP2008105178A JP5224887B2 (en) | 2007-04-20 | 2008-04-14 | Image forming apparatus |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010105304556A Division CN101976026B (en) | 2007-04-20 | 2008-04-18 | Image forming device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101290491A true CN101290491A (en) | 2008-10-22 |
| CN101290491B CN101290491B (en) | 2010-12-15 |
Family
ID=40034797
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010105304556A Expired - Fee Related CN101976026B (en) | 2007-04-20 | 2008-04-18 | Image forming device |
| CN2008100929347A Expired - Fee Related CN101290491B (en) | 2007-04-20 | 2008-04-18 | Image forming apparatus |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010105304556A Expired - Fee Related CN101976026B (en) | 2007-04-20 | 2008-04-18 | Image forming device |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP5224887B2 (en) |
| KR (1) | KR100970284B1 (en) |
| CN (2) | CN101976026B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104635455A (en) * | 2013-11-13 | 2015-05-20 | 佳能株式会社 | Image forming apparatus |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014174377A (en) | 2013-03-11 | 2014-09-22 | Ricoh Co Ltd | Developing device and image forming apparatus including the same |
| EP3195063B1 (en) | 2014-09-17 | 2019-05-01 | Ricoh Company, Ltd. | Developing device and image forming apparatus |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2701848B2 (en) * | 1987-09-24 | 1998-01-21 | 三田工業株式会社 | Development method |
| JP3186362B2 (en) * | 1993-08-26 | 2001-07-11 | 花王株式会社 | Manufacturing method of electrostatic image developer |
| US6381434B1 (en) | 1996-11-14 | 2002-04-30 | Canon Kabushiki Kaisha | Developing apparatus with electric field force directing a toner cloud for coating a developer carrying member |
| JPH11212362A (en) | 1998-01-20 | 1999-08-06 | Canon Inc | Developing device |
| JP4590303B2 (en) * | 2004-05-13 | 2010-12-01 | キヤノン株式会社 | Magnetic material-containing resin carrier and two-component developer |
| JP4001606B2 (en) * | 2005-05-31 | 2007-10-31 | パウダーテック株式会社 | Resin-filled carrier and electrophotographic developer using the carrier |
| JP4001609B2 (en) * | 2005-08-25 | 2007-10-31 | パウダーテック株式会社 | Carrier for electrophotographic developer and electrophotographic developer using the carrier |
| CN100570504C (en) * | 2005-09-21 | 2009-12-16 | 佳能株式会社 | Image processing system |
| JP5207702B2 (en) | 2006-10-20 | 2013-06-12 | キヤノン株式会社 | Image forming apparatus |
-
2008
- 2008-04-14 JP JP2008105178A patent/JP5224887B2/en not_active Expired - Fee Related
- 2008-04-18 CN CN2010105304556A patent/CN101976026B/en not_active Expired - Fee Related
- 2008-04-18 CN CN2008100929347A patent/CN101290491B/en not_active Expired - Fee Related
- 2008-04-18 KR KR1020080036339A patent/KR100970284B1/en not_active IP Right Cessation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104635455A (en) * | 2013-11-13 | 2015-05-20 | 佳能株式会社 | Image forming apparatus |
| CN104635455B (en) * | 2013-11-13 | 2019-05-31 | 佳能株式会社 | Image forming apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20080094622A (en) | 2008-10-23 |
| JP2008287243A (en) | 2008-11-27 |
| CN101976026B (en) | 2012-11-28 |
| CN101290491B (en) | 2010-12-15 |
| CN101976026A (en) | 2011-02-16 |
| JP5224887B2 (en) | 2013-07-03 |
| KR100970284B1 (en) | 2010-07-15 |
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