WO2019209554A1 - Toner pour développer une image électrostatique, et moyen d'alimentation en toner et appareil pour former une image étant doté de celui-ci - Google Patents

Toner pour développer une image électrostatique, et moyen d'alimentation en toner et appareil pour former une image étant doté de celui-ci Download PDF

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Publication number
WO2019209554A1
WO2019209554A1 PCT/US2019/027295 US2019027295W WO2019209554A1 WO 2019209554 A1 WO2019209554 A1 WO 2019209554A1 US 2019027295 W US2019027295 W US 2019027295W WO 2019209554 A1 WO2019209554 A1 WO 2019209554A1
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WO
WIPO (PCT)
Prior art keywords
toner
polyester resin
unit
kda
crystalline polyester
Prior art date
Application number
PCT/US2019/027295
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English (en)
Inventor
Sungyul KIM
Dongwon Kim
Seungsik Woo
Youngjae Kwon
Yongtae Kim
Original Assignee
Hewlett-Packard Development Company, L.P.
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Application filed by Hewlett-Packard Development Company, L.P. filed Critical Hewlett-Packard Development Company, L.P.
Publication of WO2019209554A1 publication Critical patent/WO2019209554A1/fr

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/093—Encapsulated toner particles
    • G03G9/09307—Encapsulated toner particles specified by the shell material
    • G03G9/09314—Macromolecular compounds
    • G03G9/09328—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • 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
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
    • G03G15/0865—Arrangements for supplying new developer
    • 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
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
    • G03G15/0887—Arrangements for conveying and conditioning developer in the developing unit, e.g. agitating, removing impurities or humidity
    • G03G15/0889—Arrangements for conveying and conditioning developer in the developing unit, e.g. agitating, removing impurities or humidity for agitation or stirring
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/0819—Developers with toner particles characterised by the dimensions of the particles
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/0827—Developers with toner particles characterised by their shape, e.g. degree of sphericity
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08755—Polyesters
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/09—Colouring agents for toner particles
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/093—Encapsulated toner particles
    • G03G9/09307—Encapsulated toner particles specified by the shell material
    • G03G9/09314—Macromolecular compounds
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/093—Encapsulated toner particles
    • G03G9/0935—Encapsulated toner particles specified by the core material
    • G03G9/09357—Macromolecular compounds
    • G03G9/09371—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/093—Encapsulated toner particles
    • G03G9/0935—Encapsulated toner particles specified by the core material
    • G03G9/09378—Non-macromolecular organic compounds
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/093—Encapsulated toner particles
    • G03G9/0935—Encapsulated toner particles specified by the core material
    • G03G9/09385—Inorganic compounds

Definitions

  • Methods of preparing toner particles suitable for an electrophotographic process or an electrostatic image recording process to develop electrostatic images in electrophotographic copiers, laser printers, electrostatic recording apparatuses, and the like may be largely classified into a pulverization method and a polymerization method.
  • a core-shell type toner particle as disclosed in US Pat. No. 6,617,091 has been suggested as one of the ways of improving low-temperature fixability. According to the method, charging deviation between colors may be reduced by inhibiting exposure of pigment surfaces.
  • a toner includes a high wax content
  • plasticization may easily occur due to partial miscibility between the binder resin and a low molecular weight portion of the wax, resulting in deterioration in terms of high- temperature storage ability or cohesiveness of the toner.
  • a method of encapsulating a surface of a binder resin with another binder resin having a relatively high glass transition temperature (Tg) has been suggested to prevent a decrease in Tg of the binder resin caused for improving low-temperature Rec
  • the term "and/or" includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.
  • a toner for developing electrostatic images may include a plurality of toner particles, each toner particle including: a core particle including a first binder resin, a colorant, and a releasing agent; and a shell layer coating the core particle and including a second binder resin.
  • the first binder resin of the core particle includes about 80 wt% or more of an amorphous polyester resin and about 20 wt% or less of a crystalline polyester resin based on a total weight of the first binder resin, and the second binder resin includes an amorphous polyester resin.
  • the amorphous polyester resin, the crystalline polyester resin, and the releasing agent may satisfy the following conditions (1 ), (2), (3), and (4):
  • SP(A), SP(C), and SP(W) are solubility parameters ((J/cm) 1/2 ) of the amorphous polyester resin, the crystalline polyester resin, and the releasing agent, respectively.
  • a weight average molecular weight Mw(C), a weight percentage Wt(C) based on a total weight of the toner, and a melting point Tm(C) of the crystalline polyester resin may satisfy the following conditions (5) and (6):
  • GPC gel permeation chromatography
  • a weight average molecular weight Mw(A) and a glass transition temperature Tg(A) of the amorphous polyester resin may further satisfy the following conditions (7) and (8):
  • Mw(A) is a weight average molecular weight (unit: kDa) of the amorphous polyester resin measured by GPC performed on a THF-soluble fraction of the amorphous polyester resin
  • Tg(C) is a glass transition temperature (unit: °C) of the amorphous polyester resin.
  • the releasing agent may include at least one selected from a polyethylene-based wax, a polypropylene-based wax, a silicone-based wax, a paraffin-based wax, an ester-based wax, a carnauba- based wax, and a metallocene-based wax.
  • a volume average particle diameter of the toner is from about 3 pm to about 9 pm.
  • an average circularity of the toner is from about 0.940 to about 0.980.
  • a volume average geometric size distribution coefficient (GSDv) and a number average geometric size distribution coefficient (GSDp) of the toner are about 1.30 or less and about 1.25 or less, respectively.
  • a toner supply device includes the toner for developing electrostatic images according to the present disclosure.
  • the toner supply device may include: a toner tank in which toner may be stored; a supply part protruding from an inner surface of the toner tank to externally supply toner from the toner tank; and a toner-agitating member rotatably disposed inside the toner tank to agitate toner in the inner space of the toner tank comprising a space above a top surface of the supplying part.
  • An imaging apparatus includes the toner for developing electrostatic images according to the present disclosure.
  • the imaging apparatus may include: an image carrier; an image forming device configured to form an electrostatic image, for example, particularly an electrostatic latent image, on a surface of the image carrier; a toner storing device, such as the toner tank above, in which toner may be stored; a toner supplying device configured to supply the toner to the surface of the image carrier to develop the electrostatic image into a visible image on the surface of the image carrier; and a transferring device configured to transfer the visible image from the surface of the image carrier to an image receiving member, wherein the toner is the toner for developing electrostatic images according to the present disclosure.
  • a method of forming an image according to the present disclosure includes forming a visible image by attaching toner to a surface of an image carrier on which an electrostatic image is formed and transferring the visible image to an image receiving member, wherein the toner is the toner for developing electrostatic images according to the present disclosure.
  • the toner for developing electrostatic images is prepared by adjusting amounts and physical properties, such as solubility parameters, thermal properties, and molecular weights, of a crystalline polyester having sharp melting characteristics, an amorphous polyester capable of improving low-temperature fixability, and a releasing agent.
  • compatibilization caused by trans-esterification, and/or other mechanism between the crystalline polyester and the amorphous polyester may be minimized by satisfying at least the above-described conditions (1 ), (2), (3), and (4). Accordingly, a domain size and distribution of the releasing agent, a domain size and distribution of the crystalline polyester resin, and a change in thermal properties of the toner may be appropriately adjusted in toner particles. As a result, the toner may maintain sharp melting Rec
  • the toner may efficiently obtain stable durability due to wide fixing offset range, high fixing gloss, and good surface shapes of toner particles.
  • the toner according to examples of the present disclosure may have excellent low-temperature fixability, wide fixing or fusing latitude, high gloss, high fluidity, and excellent surface characteristics of particles (i.e., excellent high-temperature storage ability and durability) via morphology control based on the above-described concepts.
  • the toner for developing electrostatic images includes a plurality of toner particles.
  • Each toner particle has a core-shell structure including a core particle including a first binder resin, a colorant, and a releasing agent and a shell layer coating the core particle and including a second binder resin.
  • the first binder resin of the core particle includes about 80 wt% or more of an amorphous polyester resin and about 20 wt% or less of a crystalline polyester resin based on a total weight of the first binder resin, and the second binder resin includes an amorphous polyester resin.
  • the first binder resin may include about 80 wt% or more of the amorphous polyester resin, particularly, about 80 wt% to about 99 wt% or about 80 wt% to about 97 wt% of the amorphous polyester resin and about 20 wt% or less of the crystalline polyester resin, particularly, about 1 wt% to about 20 wt% or about 3 wt% to about 20 wt% of the crystalline polyester resin based on a total weight of the first binder resin. Polyester resins may efficiently enhance color reproducibility.
  • the toner particles may have high strength and excellent low-temperature fixability, excellent high- temperature storage ability, and excellent charging characteristics, and deterioration of image quality due to contamination of members, such as an image forming device or, a photoconductor drum, of the imaging apparatus employing the toner may be efficiently inhibited in the imaging apparatus.
  • the crystalline polyester resin refers to a polyester resin that shows a definite or sharp endothermic peak representing fusion or melting of crystallites in a differential scanning calorimetry (DSC) thermogram.
  • the crystalline polyester resin may be defined as a polyester resin that has a full width at half maximum (FWHM) of the endothermic peak of 15 °C or less in a DSC thermogram which is obtained using a temperature increasing rate of 10 °C/min.
  • the crystalline polyester resin is used to improve image gloss and low-temperature fixability of the toner.
  • the amorphous polyester resin refers to a polyester resin that does not show a definite or sharp endothermic peak representing fusion or melting of crystallites in a DSC thermogram.
  • the amorphous polyester resin may be defined as a polyester resin that exhibits a stepwise change (a so-called“base line shift” phenomenon) in an amount of heat absorption or has a FWHM of the endothermic peak of the amorphous polyester resin which is greater than 15 °C in a DSC thermogram which is obtained using a temperature increasing rate of 10 °C/min.
  • the melting point Tm of the crystalline polyester resin may be from about 60 °C to about 100 °C, for example, from about 60 °C to about 95 °C, from about 60 °C to about 90 °C, from about 62 °C to about 90 °C, from about 63 °C to about 80 °C, from about 65 °C to about 75 °C, or from about 65 °C to about 70 °C.
  • the melting point of the crystalline polyester resin is from about 60 °C to about 100 °C, for example, from about 60 °C to about 90 °C, aggregation of toner particles may be efficiently inhibited, preservability of fixed images may be improved, and low- temperature fixability may be enhanced.
  • the glass transition temperature Tg of the amorphous polyester resin may be from about 50 °C to about 75 °C, for example, from about 55 °C to about 70 °C, or from about 60 °C to about 70 °C, or from about 62 °C to about 69 °C.
  • the toner When the crystalline polyester resin is added to the amorphous polyester resin, the toner has high fixability near a melting temperature of the crystalline polyester resin according to sharp melting characteristics of the crystalline polyester resin, i.e. , according to an effect of remarkable reduction of viscosity Rec
  • the toner may have quick and high fixability at a low-temperature.
  • the high Tg of the amorphous polyester resin is maintained by suitably mixing the crystalline polyester resin and the amorphous polyester resin, and the toner has a remarkably reduced viscosity at a fixing temperature according to the sharp melting characteristics of the crystalline polyester resin.
  • the compatibility of the crystalline and amorphous polyester resins is necessarily controlled.
  • the toner according to the examples of the present disclosure may be prepared by preparing latex (emulsion) of each polyester resin in such a way that the particle size is from about 100 to about 300 nm, and then growing the particle size to be used as the toner through an aggregation and coalescence process after mixing.
  • the aggregation process may be performed at Tg of the amorphous polyester resin or below, but the coalescence process may be performed at Tg of the amorphous polyester resin and the melting temperature of the crystalline polyester resin or above. Accordingly, each polyester resin maintains a molten state for about 2 to about 3 hours during the coalescence Rec
  • compatibility between a polyester binder resin and a releasing agent is strictly controlled by designing the crystalline polyester resin and the amorphous polyester resin of the core particle according to the above-described conditions such that the melting temperature of the crystalline polyester resin and the Tg of the amorphous polyester resin do not remarkably change after the toner is prepared, thereby satisfactorily maintaining high-temperature storage characteristics, low- temperature fixability, wide fusing latitude, and high gloss of the toner.
  • Polyester resins may be prepared by reacting an aliphatic, an alicyclic, or an aromatic polycarboxylic acid (polycarboxylic acid) or an alkyl ester thereof with a polyhydric alcohol, e.g., an aliphatic polyhydric alcohol through a direct esterification reaction or trans-esterification reaction.
  • a polyhydric alcohol e.g., an aliphatic polyhydric alcohol
  • the crystalline polyester resin may be prepared by reacting an aliphatic polycarboxylic acid having at least C8 (excluding carbon atoms of the carboxyl groups), for example, from C8 to C12, in detail, from C9 to C10, with an aliphatic alcohol having at least C8, for example, from C8 to C12, in detail, from C10 to C12.
  • the crystalline polyester resin may be obtained by reacting 1 ,9-nonanediol and 1 ,10-decane dicarboxylic acid, or 1 ,9- nonanediol and 1 , 12-dodecane dicarboxylic acid.
  • the crystalline polyester resin may have a melting temperature suitable to be used for toner.
  • such crystalline polyester resin has a higher linearity, and thus has a higher affinity to the amorphous polyester resin.
  • the crystalline polyester resin may have a weight average molecular weight Mw of, for example, from about 8,000 g/mol to about 60,000 g/mol, particularly, from about 10,000 g/mol to about 50,000 g/mol, from about 13,000 Rec
  • g/mol to about 40,000 g/mol from about 15,000 g/mol to about 35,000 g/mol, from about 15,000 g/mol to about 32,000 g/mol, from about 17,000 g/mol to about 32,000 g/mol, from about 18,000 g/mol to about 30,000 g/mol, or from about 18,000 g/mol to about 28,000 g/mol, when measured for a tetrahydrofuran (THF)-soluble fraction by gel permeation chromatography (GPC).
  • GPC gel permeation chromatography
  • the polyester resin may be prepared at a polymerization temperature of about 180°C to about 230°C, in a reaction system under a reduced pressure if needed, while water or alcohol produced during condensation reaction is removed.
  • a solvent having a high boiling point may be added thereto as a solubilizer to dissolve the polymerizable monomer.
  • Polycondensation may be performed while removing a solubilizer by distillation.
  • Examples of a catalyst that may be used in the preparation of the crystalline polyester resin include, but are not limited to, a compound of an alkaline metal such as sodium and lithium, a compound of an alkaline earth metal such as magnesium and calcium, a compound of a metal such as zinc, manganese, antimony, titanium, tin, zirconium, and germanium; a phosphorous acid compound; a phosphoric acid compound; or an amine compound.
  • dicarboxylic acid dicarboxylic acid
  • naphthalene-2, 6-dicarboxylic acid anthracenedicarboxylic acid, and/or cyclohexanedicarboxylic acid.
  • polycarboxyl ic acids include trimellitic acid, pyromellitic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, pyrenetetracarboxylic acid.
  • An acid anhydride, an acid chloride, or an ester may also be used instead of the carboxylic acids in which the carboxylic groups of the carboxylic acids are converted to an anhydride group, an acyl chloride group, or an ester group, respectively.
  • carboxylic acids in which the carboxylic groups of the carboxylic acids are converted to an anhydride group, an acyl chloride group, or an ester group, respectively.
  • terephthalic acid or a lower ester thereof, diphenylacetic acid, or cyclohexane dicarboxylic acid, among the polyvalent cyclic acids listed above may be used.
  • a lower ester means an ester of a C1 -C8 aliphatic alcohol.
  • Examples of the polyhydric alcohol that may used to obtain the amorphous polyester resin include aliphatic diols, such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, and glycerine; alicyclic diols, such as cyclohexane diol, cyclohexane dimethanol, and hydrogenated bisphenol A; and aromatic diols, such as an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A.
  • aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, and glycerine
  • alicyclic diols such as cyclohexane diol,
  • polyhydric alcohols may be used alone or in a combination of at least two thereof.
  • aromatic diols or alicyclic diols among the polyhydric alcohols listed above, may be used.
  • aromatic diols may be used.
  • trihydric or higher alcohols such as glycerin, trimethylolpropane, or pentaerythritol, may be used together with diols to provide a cross-linked or branched structure.
  • the amorphous polyester resin may be prepared by condensating the polyhydric alcohol and the polycarboxyl ic acid according to a general method.
  • the polyhydric alcohol and the polycarboxylic acid are mixed, together with a catalyst, if necessary, in a reaction vessel equipped with a thermometer, a stirrer, and a condenser, e.g., a down flow type condenser, and heated at 150°C to 250°C in an inert gas (for example, nitrogen gas) until the mixture reaches a predetermined acid value, while residual low-molecular weight compounds are continuously removed from the reaction system.
  • an inert gas for example, nitrogen gas
  • reaction product is cooled to obtain an amorphous polyester resin as a final reaction product.
  • Examples of a catalyst that may be used in the synthesis of the amorphous polyester resin include, but are not limited to, an antimony-based, a tin-based, a titanium-based, or an aluminum-based catalyst.
  • an esterification catalyst such as an organometallic compound, e.g., dibutyltin dilaurate or dibutyltin oxide or a metal compound, e.g., tetrabutyl titanate may be used.
  • a titanium-based compound or an aluminum-based compound may be used.
  • the amount of the catalyst may be adjusted in the range of about 0.01 wt% to about 1.00 wt% based on a total amount of the reactants.
  • the amorphous polyester resin may have a weight average molecular weight Mw of, for example, from about 5,000 g/mol to about 60,000 g/mol, particularly, from about 10,000 g/mol to about 50,000 g/mol, from about 12,000 g/mol to about 45,000 g/mol, from about 12,000 g/mol to about 25,000 g/mol, from about 15,000 g/mol to about 40,000 g/mol, from about 15,000 g/mol to about 35,000 g/mol, from about 15,000 g/mol to about 30,000 g/mol, from about 15,000 g/mol to about 28,000 g/mol, from about 15,000 g/mol to about 27,000 g/mol, from about 15,000 g/mol to about 25,000 g/mol, from about 15,000 g/mol to about 22,000 g/mol, or from about 15,000 g/mol to about 20,000 g/mol, when measured for a tetrahydrofuran(THF)-soluble fraction by
  • low-temperature fixability and anti-hot offset characteristics may be improved and a decrease in strength of the resin may be suppressed, thereby improving the strength of an image fixed on a paper.
  • storage characteristics, such as anti-blocking characteristics, of the toner may also be improved.
  • the amorphous polyester resin of the first binder resin may be same as or different from the amorphous polyester resin of the second binder resin.
  • the releasing agent increases low-temperature fixability of the toner and durability and abrasion resistance of a final image, types and amounts of Rec
  • the releasing agent may greatly influence the characteristics of the toner.
  • the releasing agent may prevent toner particles from adhering to the heating roller of a fixing device.
  • the releasing agent may be a natural wax or a synthetic wax.
  • Examples of the releasing agent include, but are not limited to, a polyethylene- based wax, a polypropylene-based wax, a silicone-based wax, a paraffin-based wax, an ester-based wax, a carnauba-based wax, a metallocene-based wax, and any mixture thereof.
  • a melting point of the releasing agent may be from about 60 °C to about 100 °C, for example, from about 65 °C to about 90 °C, from about 65 °C to about 80 °C, from about 67 °C to about 77 °C, or from about 67 °C to about 75 °C.
  • the releasing agent is physically attached to toner particles, but is not covalently bonded with toner particles.
  • the amount of the releasing agent contained in the core particle may be, for example, from about 1 part by weight to about 20 parts by weight, from about 2 parts by weight to about 16 parts by weight, or from about 3 parts by weight to about 12 parts by weight based on 100 parts by weight of the toner.
  • the amount of the releasing agent is 1 part by weight or more, excellent low-temperature fixability and a sufficient fixing temperature range may be obtained.
  • the amount of the releasing agent is 20 parts by weight or less, storage characteristics and economic feasibility may be improved.
  • the releasing agent may be an ester group-containing wax.
  • the ester group-containing wax include (1 ) mixtures including an ester-based wax and a non-ester-based wax; and (2) an ester group-containing wax prepared by adding an ester group to a non-ester-based wax. Since an ester group has high affinity with respect to the binder component of the toner, the ester group-containing wax may be uniformly distributed among toner particles, and thus may effectively function.
  • the non-ester-based wax may suppress an excessive plasticizing effect, which occur when an ester-based wax is exclusively used. Therefore, toner containing the mixture wax may retain satisfactory development characteristics for a long period of time.
  • ester group-containing wax examples include a mixture including paraffin-based wax and an ester-based wax; and an ester group-containing Rec
  • paraffin-based wax examples thereof include P-212, P-280, P-318, P- 319, P-419 and T-289 available from Chukyo Yushi Co., Ltd; and NCM9385 available from Sasol Corporation, and the like.
  • the amount of the ester-based wax may be in the range of about 5 to about 39 wt %, for example, about 7 to about 36 wt %, or about 9 to about 33 wt %, based on the total weight of the mixture.
  • toner When the amount of the ester-based wax is greater than or equal to about 5 wt % based on the total weight of the mixture, the compatibility of the ester-based wax with a binder resin may be sufficiently maintained. When the amount of the ester-based wax is less than or equal to about 39 wt % based on the total weight of the mixture, toner may have appropriate plasticizing characteristics, and thus may retain satisfactory development characteristics for a long period of time.
  • compatibilization caused by trans-esterification, and/or other mechanism between the crystalline polyester and the amorphous polyester may be minimized by satisfying at least the conditions (1 ), (2), (3), and (4). Accordingly, a domain size and distribution of the releasing agent, a domain size and distribution of the crystalline binder resin, and a change in thermal properties of the toner may be appropriately adjusted in the toner particles. As a result, the toner may have sharp melting characteristics of the crystalline polyester and a high Tg of the amorphous polyester. Thus, the toner according to examples of the present disclosure may efficiently obtain stable durability due to wide fixing offset range, high fixing gloss, and good surface shapes of the toner particles.
  • the toner according to examples of the present disclosure may have excellent low-temperature fixability, good surface characteristics of the toner particles, fluidity, charging stability, high-temperature storage ability, and durability against environmental changes.
  • the toner according to examples of the present disclosure may have excellent properties such as high resolution, excellent durability, high gloss, low fixing temperature, and wide fusing latitude. Rec
  • Thermal and physical properties of polyester-based polymerization toner are affected by an inner morphological structure of toner particles which, in turn, is considerably affected by compatibility between components.
  • compatibility between the polyester binder resin and the releasing agent directly affects a domain size and dispersity of each component of the toner particles, and viscosity of the toner.
  • factors related to the compatibility include interfacial tension, solubility parameter (SP), an average molecular weight, distribution of molecular weights, and acidic values. For example, when the solubility parameters between two components are similar, compatibility tends to be good, and thus this relationship may be used for designing a toner structure.
  • the solubility parameters of the binder resin and the releasing agent may be selected to form a combination which makes them an immiscible or partially miscible mixture. Furthermore, when a quantitative analysis result of the domain sizes and domain number of the releasing agent on a cross-section of the toner particle, and distribution of low molecular weight components are considered together, the possibility of plasticization may be predicted.
  • compatibilities between the amorphous polyester resin, the crystalline polyester resin, and the releasing agent of the toner according to examples of the present disclosure are adjusted to satisfy the following conditions (1 ) and (2).
  • SP(A), SP(C), and SP(W) are solubility parameters (unit: (J/cm) 1/2 ) of the amorphous polyester resin, the crystalline polyester resin, and the releasing agent, respectively. Domains of the crystalline polyester resin and the releasing agent may be well formed by increasing the solubility parameter of the amorphous polyester resin to satisfy the conditions (1 ) and (2). As a result, the surface shape of the toner particle may be improved to inhibit the releasing agent from being exposed through the surface of the toner particle, thereby inhibiting excessive aggregation of toner particles and improving high- temperature storage ability, i.e. , durability. Rec
  • the numerical range of the condition (1 ) may be about 1 .2 to about 1 .8, about 1.3 to about 1.7, about 1.4 to about 1 .7, about 1 .5 to about 1 .7, or about 1 .51 to about 1.65.
  • the numerical range of the condition (2) may be, more particularly, about 2.6 or more, about 2.7 or more, about 2.8 or more, or about 2.9 or more.
  • the toner may have good surface shapes of the toner particles, wide fusing latitude, and high gloss:
  • Mw(C) is a weight average molecular weight (unit: kDa) of the crystalline polyester resin measured by GPC performed on a THF-soluble fraction of the crystalline polyester resin
  • Wt(C) is a weight percentage (unit: wt%) of the crystalline polyester resin based on a total weight of the toner
  • Mw(A) is a weight average molecular weight (unit: kDa) of the amorphous polyester resin measured by GPC performed on a THF-soluble fraction of the amorphous polyester resin.
  • a releasing agent-crystalline polyester resin hybrid domain is formed due to a difference of compatibility therebetween.
  • the melting point of the releasing agent and the melting point of the crystalline polyester resin are merged to have a single value.
  • sharp melting of the toner becomes possible, and thus low-temperature fixability and gloss of the toner may be improved and the surface shapes of the toner particles may be enhanced:
  • SP(A), SP(C), and SP(W) are as defined above.
  • the numerical range of the condition (3) may be, more particularly, about 1 .55 or less, about 1.50 or less, about 1 .47 or less, about 1 .45 or less, or about 1 .40 or less.
  • the weight average molecular weight Mw(C), the weight percentage Wt(C) based on the total weight of the toner, and the melting point Tm(C) of the crystalline polyester resin may be adjusted to satisfy the conditions (5) and (6).
  • the low-temperature fixability, surface shape, and high-temperature storage ability of the toner may be improved.
  • Mw(C) is a weight average molecular weight (unit: kDa) of the crystalline polyester resin measured by GPC performed on a THF-soluble fraction
  • Wt(C) is a weight percentage (unit: wt%) of the crystalline polyester resin based on a total weight of the toner
  • Tm(C) is a melting point (unit: °C) of the crystalline polyester.
  • the numerical range of the condition (5) may be about 3.0 to about 5.0, about 3.2 to about 5.0, about 3.4 to about 5.0, or about 3.2 to about 4.8 (unit: kDa/wt%). Rec
  • the numerical range of the condition (6) may be about 60 °C to about 80 °C, about 62 °C to about 70 °C, about 64 °C to about 70 °C, about 65 °C to about 69 °C, or about 66 °C to about 69 °C.
  • High-temperature storage ability of the toner may further be improved by adjusting the weight average molecular weight and the glass transition temperature of the amorphous polyester resin to satisfy the conditions (7) and (8) in the preparation of the toner according to examples of the present disclosure.
  • Mw(A) is a weight average molecular weight (unit: kDa) of the amorphous polyester resin measured by GPC performed on a THF-soluble fraction
  • Tg(C) is a glass transition temperature (unit: °C) of the amorphous polyester resin.
  • the numerical range of the condition (7) may be about 12.0 kDa to about 22.0 kDa, about 12.0 kDa to about 20.0 kDa, about 12.0 kDa to about 18.0 kDa, about 12.0 kDa to about 16.0 kDa, or about 12.0 kDa to about 15.0 kDa.
  • the numerical range of the condition (8) may be about 55 °C to about 70 °C, about 58 °C to about 68 °C, about 60 °C to about 68 °C, or about 62 °C to about 68 °C.
  • the toner having excellent low-temperature fixability, high gloss, and high high-temperature storage ability may be provided by strictly controlling compatibilities between components of the toner by adjusting the solubility parameters, the molecular weights, and the amounts of the polyester resins and the releasing agent used to prepare the core particles of the toner.
  • the toner may include iron (Fe), silicon (Si), and zinc (Zn), wherein the amounts of Si and Fe are each in the range of about 3 to about 1000 ppm, a molar ratio of Si to Fe (Si/Fe) is in the range of about 0.1 to about 5, and the [Si]/[Fe] ratio and the [Zn]/[Fe] ratio may satisfy the following conditions (9) and (10), wherein [Si], [Zn] and [Fe] denote the intensities of Si, Zn and Fe, respectively, as measured by X-ray fluorescence spectrometry: Rec
  • the intensity of zinc [Zn] is a value corresponding to the amount of zinc contained in a zinc-containing compound that is used as a catalyst in polymerizing the binder latex of the toner, i.e., the polyester resins. If [Zn] is too low, polymerization efficiency may be considerably low, and it may take longer to complete the reaction. On the other hand, if [Zn] is too large, the reaction rate may be too high to be controlled, and the molecular weight may be significantly increased so that the resulting toner may not be able to be appropriately fixed at low temperatures. Furthermore, if [Zn] is too large, the electrical characteristics of the final toner may be adversely affected. Thus, [Zn] is to be controlled within an appropriate range.
  • the intensity of iron [Fe] is a value corresponding to the amount of Fe contained in an aggregating agent (or coagulant) that is used to aggregate the binder latex, the colorant and the releasing agent when toner is prepared. Thus, [Fe] may affect the aggregation properties, the particle size distribution and the particle size of aggregated toner.
  • the intensity of silicon [Si] is a value corresponding to the amount of Si contained in an aggregating agent used for the toner or a silica external additive that is added to obtain the flowability of the toner. [Si] may affect properties of the toner like Fe, and may also affect flowability of the toner.
  • the ratio of [Zn] to [Fe], i.e., the [Zn]/[Fe] ratio may be from about 5.0x10 ⁇ 4 to about 5.0x10 3 , for example, from about 5.0x10 ⁇ 3 to about 5.0x10 ⁇ 2 .
  • the [Zn]/[Fe] ratio is within the range described above, appropriate aggregation rate and degree of aggregation may be obtained in the preparation of latex and excellent charging characteristics of the toner may be maintained.
  • the ratio of [Si] to [Fe], i.e., the [Si]/[Fe] ratio may be, for example, in the range of about 5.0x1 O 4 to about 5.0x1 O 2 , about 8.0x1 O 4 to about 3.0x1 O 2 , or about 1 .0x1 O 3 to about 1.0x10 2 .
  • the toner may have high flowability and the contamination of the internal components of the image forming apparatus in which the toner is employed may be suppressed. Rec
  • the intensity of silicon [Si], the intensity of zinc [Zn], and the intensity of iron [Fe] may be measured by X-ray fluorescence spectrometry using an energy dispersive X-ray spectrometer (EDX-720) available from SHI MADZU Corporation. The measurement may be performed at an X-ray tube voltage of about 50 kV with a sample molding amount of 3 g ⁇ 0.01 g.
  • the ion intensity ratios [Zn]/[Fe] and [Si]/[Fe] of each sample may be calculated by using quantitative results of the intensities of silicon [Si], zinc [Zn], and iron [Fe] (unit: cps/mA) obtained by the X-ray fluorescence measurement.
  • the core particles of the toner for developing electrostatic images according to examples of the present disclosure include a colorant.
  • the colorant include a black colorant, a cyan colorant, a magenta colorant, a yellow colorant, or any combination thereof.
  • the black colorant may be carbon black, aniline black, or a mixture thereof.
  • the yellow colorant may be a condensed nitrogen compound, an isoindolelinone compound, an anthraquinone compound, an azo metal complex, an arylimide compound, or a mixture thereof. More particularly, examples of the yellow colorant include, but are not limited to, C.l. pigment yellows 12, 13, 14, 17, 62, 74, 83, 93, 94, 95, 109, 1 10, 1 1 1 , 128, 129, 147, 168, and 180.
  • the magenta colorant may be a condensed nitrogen compound, an anthraquine compound, a quinacridone compound, a basic dye lake compound, a naphthol compound, a benzoimidazole compound, a thioindigo compound, a perylene compound, or a mixture thereof. More particularly, examples of the magenta colorant include, but are not limited to, C.l. pigment reds 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57: 1 , 81 : 1 , 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221 , and 254.
  • the cyan colorant may be a copper phthalocyanine compound or a derivative thereof, an anthraquinone compound, a basic dye lake compound, or a mixture thereof. More particularly, examples of the cyan colorant include, but are not limited to, C.l. pigment blues 1 , 7, 15, 15:1 , 15:2, 15:3, 15:4, 60, 62, and 66. Rec
  • colorants may be used alone or in combination of at least two thereof, and may be selected in consideration of color, chromaticity, brightness, weather resistance, or dispersibility in toner particles.
  • the amount of the colorant is not limited as long as it is sufficient to color the toner.
  • the amount of the colorant may be in the range of about 0.5 to about 15 parts by weight, about 1 to about 12 parts by weight, or about 2 to about 10 parts by weight, based on 100 parts by weight of the toner.
  • the amount of the colorant is about 0.5 parts by weight or above based on 100 parts by weight of the toner, a coloring effect may be satisfactorily shown.
  • the amount of the colorant is about 15 parts by weight or less, a preparation cost of the toner does not significantly increase, and a sufficient amount of charge may be provided.
  • the toner according to examples of the present disclosure may have a volume average particle diameter of about 3 to about 9 pm, for example, from about 4 to about 8 pm or from about 4.5 to about 7.5 pm.
  • the smaller the toner particle size the higher the resolution and the higher the quality of an image that may be achieved.
  • the volume average diameter of the toner may be measured by electrical impedance analysis.
  • volume average diameter When the volume average diameter is 3 pm or above, photoreceptor (or photoconductor) cleaning may be easily performed, a mass production yield may be improved, problems generated through scattering may be suppressed, and a high resolution and high quality image may be obtained.
  • volume average diameter When the volume average diameter is 9 pm or lower, charging may be uniformly performed, fixability of the toner may be improved, and a doctor blade may easily control the toner layer on the photoreceptor.
  • An average circularity of the toner may be in the range of about 0.940 to about 0.980.
  • the average circularity may be in the range of about 0.945 to about 0.975, or about 0.950 to about 0.970.
  • the average circularity may be calculated as follows.
  • the average circularity may be in the range of 0 to 1 , and as the average circularity approaches 1 , the toner particle shape Rec
  • the toner has an average circularity of 0.940 or greater, an image developed on a transfer medium may have an appropriate thickness, and thus toner consumption may be reduced. In addition, voids between toner particles are not too large, and thus the image developed on the transfer medium may have a sufficient covering rate.
  • the toner has an average circularity of 0.980 or less, an excessive amount of toner being supplied onto a developer sleeve may be prevented, enabling to reduce the contamination of the developer sleeve that may result from the non- uniform coating of toner thereon.
  • the toner particle size distribution may be assessed using a volume average geometric size distribution coefficient (GSDv) or a number average geometric size distribution coefficient (GSDp).
  • GSDv and GSDp of the toner according to examples of the present disclosure may be, respectively, about 1.3 or less and about 1 .25 or less.
  • the GSDv may be about 1 .30 or less, for example, from about 1.15 to about 1 .30.
  • the GSDp may be about 1.25 or less, for example, from about 1 .20 to about 1.25.
  • the toner may have a uniform particle diameter. A method of measuring the GSDv or GSDp will be described below.
  • the shell layer is disposed or coated on the core particle.
  • the shell layer includes the second binder resin including the amorphous polyester resin.
  • the shell layer prevents crystalline materials, such as the crystalline polyester resin and the releasing agent, of the core particle that adversely affect the charging characteristics of the toner from being externally exposed, thereby increasing the charging stability and durability of the toner.
  • the toner for developing an electrostatic image may be prepared by an aggregation method.
  • the aggregation method may be performed by, for example, mixing a binder resin dispersion, a colorant dispersion, and a releasing agent dispersion; aggregating particles thereof; and fusing resultant aggregates.
  • the toner according to examples of the present disclosure may be prepared by an emulsion aggregation (EA) method suitable for precisely controlling particle size Rec
  • the toner according to examples of the present disclosure may be prepared to have a core-shell structure that stably forms a high quality image for a long period of time since the polymerization toner not only has excellent durability with respect to an environment, but also excellent color realization, low-temperature fixability, charging stability, and high-temperature storage characteristics.
  • the toner according to examples of the present disclosure may be prepared by the EA method described below.
  • the polyester resin polymerized as described above is subjected to phase inversion emulsification to obtain a polyester latex having a latex particle size of about 100 nm to about 300 nm.
  • the polyester latex may be obtained by dispersing a polyester resin, an alkaline compound, and optionally, a surfactant in an aqueous phase and subjecting the dispersion to phase inversion emulsification.
  • a latex preparation process according to this method includes a dissolution/neutralization, an emulsification, and a solvent evaporation steps. In the dissolution/neutralization step, the polyester resin is dissolved in an organic solvent to prepare an organic polyester solution. A solvent capable of dissolving the polyester resin may be used as the organic solvent.
  • the alkaline compound and water are added to the prepared resin solution to perform phase inversion emulsification.
  • the surfactant may be added thereto.
  • An amount of the alkaline compound may be determined to be equivalent to an amount of carboxylic acid groups obtained from an acid value of the polyester resin.
  • the obtained polyester latex particles, a pigment dispersion, a releasing agent, and an aggregating agent are mixed, optionally with a homogenizer, and agitated. Then, primary aggregates corresponding to core particles are generated by shear-induced aggregation mechanism.
  • the latex is further added thereto at a temperature of about 25 °C to about 70 °C (lower than Tg of the polyester resin), more particularly, about 35 °C to about 60 °C to form a shell layer on the core particle, and then a coalescence process is performed at a temperature of about 85 °C to about 100 °C (higher than the Tg Rec
  • the aggregating agent that may be used in the aggregation process may include polysilicato-iron compounds obtainable under the tradename of PSI-025, PS1 -050, PSI-075, or PSI-100 available from SUI DO KIKO CO., LTD.
  • the polysilicato-iron aggregating agent exhibits strong aggregating force even when used in a small amount at a low temperature.
  • the polysilicato-iron aggregating agent includes iron and silicon as the main components, adverse effects of residual aluminum on the environment and human body caused when a trivalent polyaluminum aggregating agent is used, may be minimized.
  • An external additive may be attached to outer surfaces of the toner particles according to examples of the present disclosure.
  • One of the main functions of the external additive is to maintain flowability of toner particles by preventing the toner particles from sticking together.
  • the external additive that may be used include particles of silica, such as fumed silica or sol- gel silica, Ti0 2 particles, and lanthanum strontium titanate (LaSrTiCb) particles.
  • the external additive may be attached to the surfaces of the toner particles, for example, by using a powder mixing apparatus. Examples of the powder mixing apparatus may be, but are not limited to, a Henshell mixer, a V-shape mixer, a ball mill, or a Nauta mixer.
  • the toner supply device includes the toner for developing electrostatic images according to the present disclosure.
  • the toner supply device includes: a toner tank in which toner may be stored; a supply part protruding from an inner surface of the toner tank to externally supply toner from the toner tank; and a toner-agitating member rotatably disposed inside the toner tank to agitate toner in the inner space of the toner tank comprising a space above a top surface of the supplying part.
  • the toner may be the toner according to the present disclosure. Rec
  • the imaging apparatus is an imaging apparatus including the toner for developing electrostatic images according to the present disclosure.
  • the imaging apparatus includes an image carrier; an image forming device configured to form an electrostatic image, for example, particularly an electrostatic latent image, on a surface of the image carrier; a toner storing device, such as the toner tank above, in which toner may be stored; a toner supplying device configured to supply the toner to the surface of the image carrier to develop the electrostatic image into a visible image on the surface of the image carrier; and a transferring device configured to transfer the visible image from the surface of the image carrier to an image receiving member, wherein the toner is the toner for developing electrostatic images according to the present disclosure.
  • the method of forming an image according to the present disclosure includes forming a visible image by attaching toner to a surface of an image carrier on which an electrostatic image is formed, and transferring the visible image to an image receiving member, e.g., a transfer medium, wherein the toner is the toner for developing electrostatic images according to the present disclosure.
  • the method of forming an image may be carried out by an electrophotographic process.
  • the electrophotographic process may include a charging step to uniformly charge the surface of an electrostatic image carrier, an exposure step to form an electrostatic image by using various photoconductive materials on the charged electrostatic image carrier, a developing step to develop a visible image (e.g., a toner image) by attaching a developer, such as toner, to the electrostatic image, a transferring step to transfer the visible image onto a transfer medium, such as paper, a cleaning step to remove toner that is not transferred and remains on the electrostatic image carrier, a charge eliminating step to remove charges remaining on the electrostatic image carrier, and a fixing step to fix the visible image by applying heat or pressure thereto.
  • the toner according to examples of the present disclosure may be efficiently used for an electrophotographic process, such as those described above. Rec
  • Glass transition temperatures Tg and melting points Tm of the amorphous polyester resins, the crystalline polyester resins, and the releasing agents shown in Table 1 are measured according to the methods described below.
  • Mw denotes a weight average molecular weight of the polyester resins measured for THF-soluble fractions by GPC.
  • amorphous polyester resin A1 About 500 g of amorphous polyester resin A1 , about 400 g of methyl ethyl ketone (MEK), and about 100 g of isopropyl alcohol (IPA) were added to a 3 L double-jacketed reactor, and the polyester resin A1 was dissolved at 30°C while stirring with an anchor-type mechanical stirrer to obtain a polyester resin solution. While agitating the obtained polyester resin solution, about 30 g of 10% aqueous ammonia solution was slowly added thereto. Then, while continuously agitating the solution, about 1 ,500 g of water was added thereto at a rate of about 50 g/min to prepare an emulsion.
  • MEK methyl ethyl ketone
  • IPA isopropyl alcohol
  • a volume average particle diameter D50 of the prepared Latex C1 measured by a particle size analyzer was about 140 nm and GSDv was about 1 .1 1 .
  • Wax dispersions purchased from Chukyo Yushi, Co., Ltd. shown in Table 1 were used.
  • Latex A2 prepared for a shell layer was added to the reactor.
  • NaOH (1 mol) was added to adjust the pH to about 7.
  • the reactor was heated to about 95 °C at a rate of 0.5 °C/min.
  • nitric acid 0.3 mol was added thereto to adjust the pH to about 5.7 and the mixture was fused for about 4 hours to about 5 hours to obtain a secondary aggregated toner having a potato shape with a volume average particle diameter of about 5.5 pm to about 6.5 pm.
  • the aggregated reaction solution was cooled to a temperature lower than Tg, and then was filtered to isolate toner particles, followed by drying.
  • the dried toner particles about 100 g of the dried toner particles, about 0.5 g of silica particles NX-90 (Nippon Aerosil), about 1 .0 g of silica particles RX-200 (Nippon Aerosil), and about 0.5 g of titanium dioxide particles SW-100 (Titan Industry Co. LTD.) were put into a mixer (KM-LS2K, available from DAE WHA Tech Co., Ltd.) and the mixture was agitated at about 8,000 rpm for 4 minutes to add an external additive to the toner particles.
  • the resultant toner had a volume average particle diameter of about 5.5 pm to about 6.0 pm.
  • the resultant toner had GSDv and GSDp of about 1 .22 and about 1.23, respectively, and an average circularity of the resultant toner was 0.972.
  • Toner particles were prepared according to Examples 2 to 5 and Comparative Examples 1 to 9 in the same manner as in Example 1 , except that types of the crystalline polyester resin, the amorphous polyester resin, and the releasing agent for core particles were changed as shown in Table 2 below.
  • the toner particle shape is checked by using a scanning electron microscope (SEM).
  • SEM scanning electron microscope
  • the circularity of toner may be measured using a flow particle image analyzer (e.g. , the FPIA-3000 particle analyzer available from SYSMEX Corporation of Kobe, Japan), and using the following equation: Rec
  • Circularity 2x(nxarea) 0 5 /circumference ... Equation.
  • the circularity may be in the range of 0 to 1 , and as the circularity approaches 1 , the toner particle shape becomes more circular. Average circularity is obtained by calculating an average circularity of 3,000 toner particles.
  • GSDv and GSDp which are measures of geometric size distribution of toner particles, are measured by using Multisizer III (manufactured by Beckman Coulter), which is a Coulter counter, under the following conditions.
  • Geometric size distribution of the toner is then divided into predetermined particle diameter ranges (channels). With respect to the respective particle diameter ranges (channels), the cumulative volume distribution of toner particles and the cumulative number distribution of toner particles are produced, wherein, in each of the cumulative volume and number distributions, the particle size in each distribution is increased in a direction from left to right.
  • a cumulative particle diameter at 16% of the respective cumulative distributions is defined as a volume average diameter D16v and a number average particle diameter D16p.
  • a cumulative particle diameter at 84% of the respective cumulative distributions is defined as a volume average diameter D84v and a number average particle diameter D84p.
  • GSDv and GSDp are calculated as follows:
  • GSDv (D84v/D16v) 0 5 ,
  • GSDp (D84p/D16p) 0 5 .
  • a DSC curve is obtained under the following heat profile, with respect to 6 to 7 mg samples in powder shape under a nitrogen gas atmosphere, by using Perkin Elmer DSC6 device. Rec
  • Cooling from 150 °C to 0 °C at a rate of -10 °C/min and maintained at a temperature of 0 °C for 1 minute,
  • Melting temperatures of the crystalline polyester resin and the releasing agent are determined based on a vertex of an endothermic peak showing a crystalline melting on the DSC curve. Also, glass transition temperature of the amorphous polyester is determined based on a half Cp value of a shoulder type curve indicating a baseline shift showing a glass transition phenomenon.
  • An NIF-type fixing device which is the same fixing device as that is installed in SL-X7600 laser printer available from Samsung Electronics Co., Ltd. is used to fix a test image under the following conditions.
  • the fixability of the fixed image is measured as follows: The optical density (OD) of the fixed image is measured, and then a 3M 810 tape is attached to the fixed image. A weight of 500 g is reciprocated thereon five times, and then the tape used is removed. Then, the OD of the fixed image is measured again.
  • Fixability (%) (OD after peeling off the tape)/(OD before peeling off the tape) X 100 Rec
  • a fixing temperature range in which the fixability is 90% or more is defined as the fusing latitude of toner.
  • COT cold-offset temperature
  • HAT hot-offset temperature
  • Gloss (%) is measured using a glossmeter (Product Name: micro-TRI- gloss available from BYK-Gardner) at a temperature of 167 °C at which the fixing device is used.
  • Cohesiveness is measured as follows to evaluate flowabiity of the toner.
  • the samples are stored for 2 hours under the conditions of room temperature (20°C ⁇ 2 °C) and relative humidity of 55+5%, the samples are sieved using each sieve under the above conditions, and changes in amount of the toner before and after sieving are measured to calculate the cohesiveness of the toner as follows.
  • the flowability of the toner is evaluated from the degree of cohesiveness measured as above according to the following criteria.
  • the toners according to Examples 1 to 5 have excellent low-temperature fixability due to low COT, wide fixing latitude defined by a difference between COT and HOT, high gloss, excellent surface characteristics of the toner, excellent high-temperature storage ability, and high flowability by controlling the components to satisfy Conditions (1 ), (2), (3) and (4) in comparison with the toners according to Comparative Examples 1 to 9.
  • the toners according to Examples 1 to 5 have wider fixing latitude and better low-temperature fixability, surface characteristics, high-temperature storage ability, and flowability than the toners according to Comparative Examples 1 to 9.

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Abstract

L'invention concerne un toner servant à développer des images électrostatiques. Le toner comprend une pluralité de particules de toner, chaque particule de toner parmi la pluralité de particules de toner comprenant une particule centrale comprenant une première résine liante, un colorant, et un agent de libération et une couche de coque recouvrant la particule centrale et comprenant une seconde résine liante. La première résine liante de la particule centrale comprend environ 80 % en poids ou plus d'une première résine de polyester amorphe et environ 20 % en poids ou moins d'une résine de polyester cristalline, le tout sur la base d'un poids total de la première résine liante, et la seconde résine liante comprend une seconde résine de polyester amorphe, la première résine de polyester amorphe, la résine de polyester cristalline et l'agent de libération ayant respectivement des paramètres de solubilité qui satisfont les conditions (1), (2), (3) et (4).
PCT/US2019/027295 2018-04-27 2019-04-12 Toner pour développer une image électrostatique, et moyen d'alimentation en toner et appareil pour former une image étant doté de celui-ci WO2019209554A1 (fr)

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WO2021150287A1 (fr) * 2020-01-20 2021-07-29 Hewlett-Packard Development Company, L.P. Toner pour développer une image électrostatique

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EP1930781A2 (fr) * 2006-12-04 2008-06-11 Fuji Xerox Co., Ltd. Tonner pour développement d'images électrostatiques, leur procédé de fabrication, développeur d'images électrostatiques, cartouche de tonner, cartouche de traitement et appareil de formation d'images
US8431307B2 (en) * 2009-11-02 2013-04-30 Samsung Electronics Co., Ltd. Electrographic toner and method of preparing the same
US8642239B2 (en) * 2011-01-31 2014-02-04 Samsung Electronics Co., Ltd. Toner for developing electrostatic charge image, method of preparing the same, device for supplying the same, and apparatus and method for forming image using the same
US20160259259A1 (en) * 2015-03-02 2016-09-08 Konica Minolta, Inc. Toner for developing electrostatic charge image

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WO2021150287A1 (fr) * 2020-01-20 2021-07-29 Hewlett-Packard Development Company, L.P. Toner pour développer une image électrostatique

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