EP0952495A1 - Toner a base de polymere et procede de production de ce dernier - Google Patents

Toner a base de polymere et procede de production de ce dernier Download PDF

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Publication number
EP0952495A1
EP0952495A1 EP97909708A EP97909708A EP0952495A1 EP 0952495 A1 EP0952495 A1 EP 0952495A1 EP 97909708 A EP97909708 A EP 97909708A EP 97909708 A EP97909708 A EP 97909708A EP 0952495 A1 EP0952495 A1 EP 0952495A1
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EP
European Patent Office
Prior art keywords
toner
polymerizable monomer
core
shell
core particles
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Granted
Application number
EP97909708A
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German (de)
English (en)
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EP0952495A4 (fr
EP0952495B1 (fr
Inventor
Tokudai Res. & Dev. Center OGAWA
Noboru Res. & Development Center YANAGIDA
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Zeon Corp
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Nippon Zeon Co Ltd
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Priority to EP08106032A priority Critical patent/EP2042932A1/fr
Publication of EP0952495A1 publication Critical patent/EP0952495A1/fr
Publication of EP0952495A4 publication Critical patent/EP0952495A4/fr
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    • 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
    • G03G9/08775—Natural macromolecular compounds or derivatives thereof
    • G03G9/08782—Waxes
    • 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
    • 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
    • G03G9/097—Plasticisers; Charge controlling agents
    • G03G9/09733—Organic compounds

Definitions

  • the present invention relates to a polymerized toner and a production process thereof, and more particularly to a polymerized toner suitable for use in developing an electrostatic latent image formed by an electrophotographic process, electrostatic recording process or the like, and a production process thereof.
  • the present invention also relates to an image forming process comprising using such a polymerized toner, and an image forming apparatus containing the polymerized toner.
  • two-component developers composed of a toner and carrier particles, and one-component developers composed substantially of a toner alone and making no use of any carrier particles are known as developers for making electrostatic latent images visible.
  • the one-component developers include magnetic one-component developers containing magnetic powder, and non-magnetic one-component developers containing no magnetic powder.
  • a flowability improver such as colloidal silica is often added independently in order to enhance the flowability of the toner.
  • the toner there are generally used colored particles obtained by dispersing a colorant such as carbon black and other additives in a binder resin and granulating the dispersion.
  • Processes for producing a toner are roughly divided into a grinding process and a polymerization process.
  • a synthetic resin, a colorant and optional other additives are melted and mixed, the mixture is ground, and the ground product is then classified so as to obtain particles having a desired particle diameter, thereby obtaining a toner.
  • a polymerizable monomer composition is prepared by uniformly dissolving or dispersing a colorant, a polymerization initiator and optional various additives such as a crosslinking agent and a charge control agent in a polymerizable monomer, the polymerizable monomer composition is dispersed in an aqueous dispersion medium containing a dispersion stabilizer by means of a stirrer to form minute droplets of the polymerizable monomer composition, and the dispersion containing the minute droplets is then heated to subject the droplets to suspension polymerization, thereby obtaining a toner (polymerized toner) having a desired particle diameter.
  • a toner polymerized toner
  • an electrostatic latent image is actually developed with the toner.
  • an image forming apparatus such as an electrophotographic apparatus or electrostatic recording apparatus
  • an electrostatic latent image is generally formed on a photosensitive member evenly charged by exposure to a light pattern, and a toner is applied to the electrostatic latent image to form a toner image (make the latent image visible).
  • the toner image is transferred to a transfer medium such as transfer paper, and the unfixed toner image is then fixed to the transfer medium by a method such as heating, pressing or use of solvent vapor.
  • the toner is often fusion-bonded to the transfer medium by passing the transfer medium, to which the toner image has been transferred, through between a heating roll (fixing roll) and a press roll to press-bond the toner to the transfer medium under heat.
  • a heating roll fixing roll
  • a press roll to press-bond the toner to the transfer medium under heat.
  • Images formed by an image forming apparatus such as an electrophotographic copying machine are required to improve their definition year by year.
  • a toner used in the image forming apparatus a toner obtained by the grinding process has heretofore been mainly used.
  • the grinding process tends to form colored particles having a wide particle diameter distribution.
  • the ground product In order for the toner to exhibit satisfactory developing characteristics, therefore, the ground product must be classified to adjust the particles so as to have a particle diameter distribution limited to a certain extent.
  • the classification itself is complicated, and its yield is poor, and so the percent yield of the toner is reduced to a great extent. Therefore, the polymerized toner easy to control its particle diameter without conducting complicated production steps such as classification has come to attract attention in recent years.
  • a polymerized toner having desired particle diameter and particle diameter distribution can be obtained without need of grinding and classification.
  • the conventional polymerized toners have involved a problem that they cannot fully meet requirements in recent years, such as the speeding-up of copying, the formation of full-color images and energy saving.
  • a step in which energy is particularly demanded in the electrophotographic system is a fixing step conducted after transferring a toner from a photosensitive member to a transfer medium such as transfer paper.
  • the toner is fixed to the transfer medium by heating and melting it. Therefore, a heating roll heated to a temperature of at least 150°C is used, and electric power is used as an energy source therefor. There is a demand for lowering the temperature of the heating roll from the viewpoint of energy saving.
  • Means for lowering the melt viscosity of the toner include a method in which the molecular weight or glass transition temperature of a binder resin used is lowered compared with the binder resins for the conventional toners. In either method, however, the toner becomes poor in shelf stability because the toner tends to undergo blocking.
  • a method for obtaining a polymerized toner having excellent fixing ability it has heretofore been proposed in, for example, Japanese Patent Application Laid-Open No. 136065/1991 to subject a polymerizable monomer containing a colorant and a charge control agent to suspension polymerization in the presence of a macromonomer.
  • the macromonomer is a relatively long-chain linear molecule having a polymerizable functional group, for example, a group containing an unsaturated bond such as a carbon-carbon double bond, at its molecular chain terminal. According to this method, the macromonomer is incorporated as a monomer unit into the molecular chain of a polymer formed.
  • the polymer apparently becomes a high molecular weight polymer due to entanglement of the branches, i.e., the so-called physical crosslinking, so that the offset resistance of the toner is improved.
  • the physical crosslinking by the macromonomer component is different from chemical crosslinking using a crosslinking monomer such as divinylbenzene and is of a loose crosslinked structure, and so the crosslinked structure is easy to be broken by heating. Accordingly, this polymerized toner is easily melted upon fixing using a heating roll and hence has excellent fixing ability.
  • the polymerized toner tends to undergo aggregation among toner particles during storage, and is hence unsatisfactory from the viewpoint of shelf stability.
  • Japanese Patent Application Laid-Open No. 173552/1985 has proposed a process in which a coating layer composed of a colorant, magnetic particles or a conductive agent, and a binder resin is formed on each surface of spherical core particles having a minute particle size by means of a jet mill.
  • the core particles there are used particles formed of a thermoplastic transparent resin such as an acrylate resin or styrene resin.
  • a toner of multi-layer structure which has excellent flowability and improved functional characteristics, can be obtained.
  • core particles having a low glass transition temperature are used in this method, however, the core particles themselves tend to undergo aggregation.
  • the coating thickness of the binder resin is liable to thicken. Accordingly, this method is difficult to provide a toner improved in both fixing ability and uniformly melting ability while retaining its good shelf stability.
  • Japanese Patent Application Laid-Open No. 259657/1990 has proposed a process for producing a toner for electrophotography, in which crosslinked toner particles prepared by suspension polymerization are added to a solution with an encapsulating polymer, a charge control agent and a parting agent dissolved in an organic solvent, and a poor solvent is then added to the resultant mixture to form a coating film of the encapsulating polymer containing the charge control agent and parting agent on each surface of the crosslinked toner particles.
  • this process it is difficult to obtain spherical particles because the solubility of the encapsulating polymer is reduced by the addition of the poor solvent to deposit the polymer on each surface of the crosslinked toner particles.
  • the capsule wall formed on the surface of each crosslinked toner particle according to this process is uneven in thickness, and moreover is relatively thick. As a result, the effects of improving development properties and fixing ability become insufficient.
  • Japanese Patent Application Laid-Open No. 45558/1982 has proposed a process for producing a toner for developing electrostatic latent images, in which core particles formed by polymerization are mixed with and dispersed in a 1 to 40 wt.% aqueous latex solution, and a water-soluble inorganic salt is then added to the dispersion to form a coating layer formed of fine particles obtained by emulsion polymerization on each surface of the core particles.
  • this process has involved a drawback that the temperature and humidity dependence of charge properties of the resultant toner becomes great due to the influence of a surfactant and the inorganic salt remaining on the fine particles, and the charge properties are deteriorated under high-temperature and high-humidity conditions in particular.
  • Japanese Patent Application Laid-Open No. 118758/1986 discloses a process for producing a toner, in which a composition containing a vinyl monomer, a polymerization initiator and a colorant is subjected to suspension polymerization to obtain core particles, and another vinyl monomer capable of providing a polymer having hydrophilicity at least equal to that of the resin contained in the core particles and a glass transition temperature higher than that of said resin is polymerized in the presence of the core particles to form shell on each of the core particles.
  • a parting agent such as low molecular weight polyethylene, carnauba wax or silicone oil may be added to the core particles for preventing a part of the toner melted from adhering to the surface of a fixing roll.
  • the vinyl monomer for forming the shell is caused to be adsorbed on each of the core particles to grow it, so that in many cases, it may be difficult to create a clear core-shell structure because the vinyl monomer absorbed in the interior of the core particles is polymerized. Accordingly, this process is difficult to provide a toner sufficiently improved in shelf stability.
  • this process is difficult to provide a toner sufficiently improved in shelf stability.
  • it has been necessary to thicken the thickness of the shell.
  • Japanese Patent Application Laid-Open No. 128908/1995 discloses a process for directly producing a polymerized toner by subjecting a monomer composition containing a polymerizable monomer, a colorant and a parting agent to suspension polymerization in an aqueous medium, the process comprising the steps of causing the parting agent to contain in a proportion of 10 to 40 parts by weight per 100 parts by weight of the polymerizable monomer and removing the parting agent on the surface of the toner formed after completion of the polymerization step.
  • a polymer having a polar group is added to the monomer to polymerize the monomer, a core-shell structure is formed because the polar polymer gathers on each surface layer of polymer particles formed.
  • the parting agent on the surface of the toner is removed, so that staining due to attachment of the parting agent (wax) to a developing drum, a photosensitive drum, a transfer drum and/or the like can be reduced.
  • this process cannot fully improve the shelf stability, fixing temperature and the like of the toner and tends to cause fogging, deterioration of image density, etc.
  • Another object of the present invention is to provide a polymerized toner which can meet the speeding-up of copying or printing, the formation of full-color images, and energy saving, and a production process thereof.
  • a further object of the present invention is to provide a polymerized toner capable of forming a toner image which exhibits excellent permeability (permeability through OHP) when conducting printing on an OHP sheet with the toner and fixing the resulting image thereto, and a production process thereof.
  • a still further object of the present invention is to provide an image forming process comprising using the polymerized toner having such excellent various properties, and an image forming apparatus in which said polymerized toner is contained.
  • This polymerized toner can be suitably produced by subjecting a composition containing the polyfunctional ester compound, the colorant and a polymerizable monomer capable of forming a polymer having a glass transition temperature of 80°C or lower to suspension polymerization, preferably, in the presence of a macromonomer to prepare colored polymer particles, and then using the colored polymer particles as core particles to subject another polymerizable monomer capable of forming a polymer having a glass transition temperature higher than that of the polymer component making up the core particles to suspension polymerization in the presence of the core particles, thereby forming shell which is formed of a polymer layer and covers each of the core particles.
  • the core particles containing the polyfunctional ester compound and the polymer component having a lower glass transition temperature permit lowering the fixing temperature of the toner, also improving the uniformly melting ability, meeting requirements such as the speeding-up of copying or printing, the formation of full-color images and good permeability through OHP, and further forming a high-quality image because they make it hard to cause fogging, deterioration of image density and the like.
  • each of the core particles can be covered with the thin shell, so that the toner can exhibit good shelf stability (blocking resistance) and moreover fully meet various requirements such as fixing ability and uniformly melting ability.
  • the present invention has been led to completion on the basis of these findings.
  • a polymerized toner of core-shell structure comprising core particles composed of colored polymer particles, which comprise a polyfunctional ester compound formed of a trifunctional or still higher polyfunctional polyhydric alcohol and a carboxylic acid, and a colorant, and shell which is formed of a polymer having a glass transition temperature higher than that of a polymer component making up the core particles and covers each of the core particles.
  • a process for producing a polymerized toner of core-shell structure which comprises the steps of (1) subjecting a polymerizable monomer composition containing a polyfunctional ester compound formed of a trifunctional or still higher polyfunctional polyhydric alcohol and a carboxylic acid, a colorant, and a polymerizable monomer for core, which is capable of forming a polymer having a glass transition temperature of 80°C or lower, to suspension polymerization in an aqueous dispersion medium containing a dispersing agent to prepare core particles formed of colored polymer particles; and then (2) subjecting a polymerizable monomer for shell, which is capable of forming a polymer having a glass transition temperature higher than that of a polymer component making up the core particles, to suspension polymerization in the presence of the core particles, thereby forming shell which is formed of a polymer layer and covers each of the core particles.
  • an image forming process comprising the steps of applying a toner to the surface of a photosensitive member, on which an electrostatic latent image has been formed, to make the latent image visible, and then transferring the visible image to a transfer medium, wherein the above-described polymerized toner of core-shell structure is used as the toner.
  • an image forming apparatus comprising a photosensitive member, a means for charging the surface of the photosensitive member, a means for forming an electrostatic latent image on the surface of the photosensitive member, a means for receiving a toner, a means for supplying the toner to develop the electrostatic latent image on the surface of the photosensitive member, thereby forming a toner image, and a means for transferring the toner image from the surface of the photosensitive member to a transfer medium, wherein the means for receiving the toner contains the above-described polymerized toner of core-shell structure.
  • the polymerized toner according to the present invention is a polymerized toner of a core-shell structure, comprising core particles and shell which covers each of the core particles.
  • the polymerized toner according to the present invention can be produced by polymerizing a polymerizable monomer for shell in the presence of core particles.
  • the core particles comprise, as essential components, a polyfunctional ester compound formed of a trifunctional or still higher polyfunctional polyhydric alcohol and a carboxylic acid, and a colorant in a polymer component (binder resin).
  • the glass transition temperature of a polymer component making up the shell is higher than that of the polymer component making up the core particles.
  • the polyfunctional ester compound useful in the practice of the present invention is an ester formed of a trifunctional or still higher polyfunctional polyhydric alcohol and a carboxylic acid.
  • trifunctional or still higher polyfunctional polyhydric alcohol examples include aliphatic alcohols such as glycerol, pentaerythritol and pentaglycerol; alicyclic alcohols such as phloroglucitol, quercitol and inositol; aromatic alcohols such as tris-(hydroxymethyl)benzene; saccharides such as D-erythrose, L-arabinose, D-mannose, D-galactose, D-fructose, L-rhamnose, saccharose, maltose and lactose; and sugar alcohols such as erythoritol, D-threitol, L-arabitol, adonitol and xylitol. Of these, pentaerythritol is preferred.
  • carboxylic acid examples include aliphatic carboxylic acids such as acetic acid, butyric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, myristic acid, stearic acid, margaric acid, arachidic acid, cerotic acid, melissic acid, erucic acid, brassidic acid, sorbic acid, linolic acid, linolenic acid, behenolic acid, tetrolic acid and ximenynic acid; alicyclic carboxylic acids such as cyclohexanecarboxylic acid, hexahydroisophthalic acid, hexahydroterephthalic acid and 3,4,5,6-tetrahydrophthalic acid; and aromatic carboxylic acids such as benzoic acid, toluic acid, cuminic acid, phthalic acid, isophthalic acid, terephthalic acid, trimes
  • carboxylic acids having, preferably, 10 to 30 carbon atoms, more preferably, 13 to 25 carbon atoms are preferred, and aliphatic carboxylic acids having the said number of carbon atoms are more preferred.
  • aliphatic carboxylic acids stearic acid and myristic acid are particularly preferred.
  • the carboxylic acids reacting with at least 3 functional groups (OH groups) of the polyhydric alcohol to form respective ester bonds may be the same or different from one another.
  • a difference between the maximum value and the minimum value in the number of carbon atoms among the carboxylic acids be preferably at most 9, more preferably at most 5.
  • the polyfunctional ester compound is preferably a compound represented by the formula (I): wherein R 1 , R 2 , R 3 and R 4 are independently an alkyl group or phenyl group, and the number of carbon atoms of the alkyl group or phenyl group is preferably 10 to 30, more preferably 13 to 25.
  • polyfunctional ester compound may be mentioned pentaerythritol tetrastearate [a compound in which R 1 , R 2 , R 3 and R 4 in the formula (I) are all CH 3 (CH 2 ) 16 groups], pentaerythritol tetramyristate [a compound in which R 1 , R 2 , R 3 and R 4 in the formula (I) are all CH 3 (CH 2 ) 12 groups] and glycerol triarachidate.
  • the polyfunctional ester compound is preferably easily soluble in a polymerizable monomer for core.
  • the polyfunctional ester compound is used in a proportion of generally 0.1 to 40 parts by weight, preferably 1 to 20 parts by weight, more preferably 3 to 15 parts by weight per 100 parts by weight of a polymer component making up core particles or a monomer for forming the polymer component (polymerizable monomer for core).
  • the proportion of the polyfunctional ester compound used falls within the above range, whereby a polymerized toner, which has a low fixing temperature and uniformly melting ability, and is excellent in shelf stability (blocking resistance) and hard to cause fogging, deterioration of image density, etc., can be provided. If the proportion of the polyfunctional ester compound used is too low, its effect becomes little. If the proportion is too high on the other hand, it is difficult to form the core particles, and the shelf stability of the resulting polymerized toner is also deteriorated.
  • dyes and pigment such as carbon black, titanium white, Nigrosine Base, aniline blue, Chalcoil Blue, chrome yellow, ultramarine blue, Orient Oil Red, Phthalocyanine Blue and Malachite Green oxalate; and magnetic powders such as cobalt, nickel, diiron trioxide, triiron tetroxide, manganese iron oxide, zinc iron oxide and nickel iron oxide.
  • colorants for magnetic color toners include C.I. Direct Red 1, C.I. Direct Red 4, C.I. Acid Red 1, C.I. Basic Red 1, C.I. Mordant Red 30, C.I. Direct Blue 1, C.I. Direct Blue 2, C.I. Acid Blue 9, C.I. Acid Blue 15, C.I. Basic Blue 3, C.I. Basic Blue 5, C.I. Mordant Blue 7, C.I. Direct Green 6, C.I. Basic Green 4 and C.I. Basic Green 6.
  • pigments for magnetic color toners include chrome yellow, cadmium yellow, Mineral Fast Yellow, Navel Yellow, Naphthol Yellow S, Hansa Yellow G, Permanent Yellow NCG, Tartrazine Lake, chrome orange, molybdenum orange, Permanent Orange GTR, Pyrazolone Orange, Benzidine Orange, cadmium red, Permanent Red 4R, Watchung Red Ca, eosine lake, Brilliant Carmine 3B, manganese violet, Fast Violet B, Methyl Violet Lake, iron blue, cobalt blue, Alkali Blue Lake, Victoria Blue Lake, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue BC, chrome green, chromium oxide, Pigment Green B, Malachite Green Lake and Final Yellow Green G.
  • magenta color pigments for full-color toners include C.I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 163, 202, 206, 207 and 209; C.I. Pigment Violet 19; and C.I. Vat Red 1, 2, 10, 13, 15, 23, 29 and 35.
  • magenta dyes for full-color toners include oil-soluble dyes such as C.I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109 and 121; C.I. Disperse Red 9; C.I. Solvent Violet 8, 13, 14, 21 and 27; and C.I. Disperse Violet 1; and basic dyes such as C.I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39 and 40; and C.I. Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27 and 28.
  • oil-soluble dyes such as C.I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109 and 121
  • C.I. Disperse Red 9 C.I. Solvent Violet 8, 13, 14, 21 and 27
  • C.I. Disperse Violet 1 and basic dyes such as C.I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17,
  • cyan color pigments for full-color toners include C.I. Pigment Blue 2, 3, 15, 16 and 17; C.I. Vat Blue 6; C.I. Acid Blue 45; and copper phthalocyanine dyes with 1 to 5 phthalimidomethyl groups added to a phthalocyanine skeleton.
  • yellow color pigments for full-color toners include C.I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 65, 73, 83 and 138; and C.I. Vat Yellow 1, 3 and 20.
  • These dyes or pigments are used in a proportion of generally 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight per 100 parts by weight of the polymer component making up the core particles or the polymerizable monomer for core.
  • the magnetic powder is used in a proportion of generally 1 to 100 parts by weight, preferably 5 to 50 parts by weight per 100 parts by weight of the polymer component making up the core particles or the polymerizable monomer for core.
  • the core particles useful in the practice of the present invention comprise, as a polymer component (binder resin), a (co)polymer of a vinyl monomer, such as a polyester resin, or a (meth)acrylic ester-styrene copolymer.
  • a polymer component binder resin
  • a (co)polymer of a vinyl monomer such as a polyester resin
  • a (meth)acrylic ester-styrene copolymer is preferred because it is easy to form particles by polymerization and control the glass transition temperature of the polymer component.
  • the volume average particle diameter (dv) of the core particles is generally 0.5 to 20 ⁇ m, preferably 1 to 10 ⁇ m. If the core particles are too great, the resolution of an image formed with such a toner tends to lower.
  • the ratio (dv)/(dp) of the volume average particle diameter (dv) to a number average particle diameter (dp) in the core particles is generally at most 1.7, preferably at most 1.5. If this ratio is too high, the resolution of an image formed with such a toner tends to lower.
  • any of emulsion polymerization, suspension polymerization, precipitation polymerization and soap-free polymerization may be used.
  • a process comprising subjecting a polymerizable monomer for core to suspension polymerization is preferred in that the polyfunctional ester compound and colorant can be uniformly contained in each of core particles formed, and the fixing ability of the resulting toner is improved.
  • the polymerizable monomer for core used in the present invention is such that can form a polymer having a glass transition temperature of generally 80°C or lower, preferably 10 to 70°C, more preferably 15 to 60°C.
  • the polymerizable monomer for core there may be used one of such monomers or any combination of such monomers. If the glass transition temperature of a polymer formed of the polymerizable monomer for core is too high, the resulting polymerized toner comes to have a higher fixing temperature and deteriorated permeability through OHP and can not meet the speeding-up of copying or printing.
  • the glass transition temperature (Tg) of the polymer is a calculated value (referred to as calculated Tg) calculated out according to the kind(s) and proportion(s) of monomer(s) used.
  • Tg the Tg of a homopolymer formed from this monomer
  • the Tg of polystyrene is 100°C. Therefore, when styrene is used as a monomer by itself, the monomer can be said to form a polymer having a Tg of 100°C.
  • the Tg of the copolymer is calculated out according to the kinds and proportions of the monomers used.
  • the monomers when 78 wt.% of styrene and 22 wt.% of n-butyl acrylate are used as monomers, the monomers can be said to form a polymer having a Tg of 50°C because the Tg of a styrene-n-butyl acrylate copolymer formed at this monomer ratio is 50°C.
  • a polymerizable monomer for core which is capable of forming a polymer having a glass transition temperature of 80°C or lower
  • the individual monomers must form respective polymers having a Tg of 80°C or lower.
  • the Tg of a homopolymer formed from the monomer must be 80°C or lower.
  • the Tg of a styrene homopolymer is 100°C
  • styrene may be used as a component of the polymerizable monomer for core so far as a copolymer having a Tg of 80°C or lower can be formed by using a mixture of styrene with a monomer (for example, n-butyl acrylate) which forms a homopolymer having a low Tg.
  • vinyl monomers are generally used as the polymerizable monomer for core.
  • Various kinds of vinyl monomers are used either singly or in combination of two or more thereof so as to adjust the Tg of the resulting polymer within the desired range.
  • vinyl monomers used in the present invention include styrenic monomers such as styrene, vinyltoluene and ⁇ -methylstyrene; acrylic acid and methacrylic acid; (meth)acrylic acid derivatives such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, dimethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dimethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide and methacrylamide; ethylenically unsaturated monoolefins such as ethylene, propylene and butylene; vinyl halides such as vinyl chloride, vinylidene chloride and vinyl fluoride;
  • a combination of a styrenic monomer with a (meth)acrylic acid derivative is preferably used as the polymerizable monomer for core.
  • a combination of a styrenic monomer with a (meth)acrylic acid derivative is preferably used as the polymerizable monomer for core.
  • styrene with butyl acrylate i.e., n-butyl acrylate
  • 2-ethylhexyl acrylate 2-ethylhexyl acrylate
  • crosslinking monomer in combination with the polymerizable monomer for core composed of the vinyl monomer(s).
  • the crosslinking monomer include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene and derivatives thereof; diethylenic esters of unsaturated carboxylic acids such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; divinyl compounds such as N,N-divinylaniline and divinyl ether; and compounds having at least three vinyl groups.
  • crosslinking monomers may be used either singly or in any combination thereof. It is desirable that the crosslinking monomer be used in a proportion of generally 0.1 to 5 parts by weight, preferably 0.3 to 2 parts by weight per 100 parts by weight of the polymerizable monomer for core.
  • a macromonomer is preferably copolymerized with the polymerizable monomer for core from the viewpoint of improving the balance between the shelf stability and fixing ability of the resulting polymerized toner.
  • the macromonomer be contained in the polymerizable monomer composition to conduct suspension polymerization.
  • the macromonomer (also referred to as macromer) is a relatively long-chain linear molecule having a polymerizable functional group (for example, a group containing an unsaturated bond such as a carbon-carbon double bond) at its molecular chain terminal.
  • the macromonomer is preferably an oligomer or polymer having a polymerizable vinyl functional group at its molecular chain terminal and a number average molecular weight of generally 1,000 to 30,000. If a macromonomer having a too low number average molecular weight is used, the surface part of the resulting polymerized toner becomes soft, and its shelf stability shows a tendency to deteriorate. If a macromonomer having a too high number average molecular weight is used on the other hand, the flowability of the macromonomer becomes poor, resulting in a polymerized toner deteriorated in fixing ability and shelf stability.
  • Examples of the polymerizable vinyl functional group which the macromonomer has at its molecular chain terminal include an acryloyl group and a methacryloyl group, with the methacryloyl group being preferred from the viewpoint of easy copolymerization.
  • the macromonomer used in the present invention preferably has a glass transition temperature higher than that of a polymer obtained by polymerizing the polymerizable monomer for core.
  • a difference in Tg between the polymer obtained by polymerizing the polymerizable monomer for core and the macromonomer may be relative.
  • the polymerizable monomer for core is such that forms a polymer having a Tg of 80°C
  • the macromonomer may also be that having a Tg of, for example, 60°C.
  • the Tg of the macromonomer is a value measured by means of an ordinary measuring device such as a DSC.
  • macromonomer used in the present invention may be mentioned polymers obtained by polymerizing styrene, styrene derivatives, methacrylic esters, acrylic esters, acrylonitrile and methacrylonitrile either singly or in combination of two or more monomers thereof; macromonomers having a polysiloxane skeleton; and those disclosed in Japanese Patent Application Laid-Open No. 203746/1991, pages 4 to 7.
  • hydrophilic macromonomers in particular, polymers obtained by polymerizing methacrylic esters or acrylic esters either singly or in combination of two or more monomers thereof are preferred in the present invention.
  • the amount of the macromonomer used is generally 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, more preferably 0.05 to 1 part by weight per 100 parts by weight of the polymerizable monomer for core. If the amount of the macromonomer used is too little, the shelf stability of the resulting polymerized toner is deteriorated. If the amount of the macromonomer used is too great, the fixing ability of the resulting polymerized toner is deteriorated.
  • the core particles be provided by subjecting the polymerizable monomer for core, the macromonomer and optionally the crosslinking monomer to suspension polymerization.
  • the suspension polymerization is generally performed in an aqueous dispersion medium containing a dispersing agent. More specifically, the suspension polymerization is conducted by mixing a polymerizable monomer (vinyl monomer) for core, a polyfunctional ester compound, a colorant, a macromonomer, an optional crosslinking monomer, a radical polymerization initiator and other additives, uniformly dispersing them by means of a ball mill or the like to prepare a liquid mixture (polymerizable monomer composition), pouring the liquid mixture into an aqueous dispersion medium containing a dispersing agent, dispersing the liquid mixture in the dispersion medium by means of a mixer having high shearing force to form minute droplets, and then subjecting them to suspension polymerization at a temperature of generally 30 to 200°C.
  • a polymerizable monomer vinyl monomer
  • a polyfunctional ester compound e.g., ethylene glycol dimethacrylate
  • a colorant e.gly
  • a dispersing agent preferably used in the present invention is colloid of a hardly water-soluble metallic compound.
  • the hardly water-soluble metallic compound may be mentioned sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; phosphates such as calcium phosphate; metal oxides such as aluminum oxide and titanium oxide; and metal hydroxides such as aluminum hydroxide, magnesium hydroxide and ferric hydroxide.
  • colloids of hardly water-soluble metal hydroxides are preferred because the particle diameter distribution of the resulting polymer particles can be narrowed, and the brightness or sharpness of an image formed from such a polymerized toner is enhanced.
  • the colloid of the hardly water-soluble metal hydroxide is not limited by the production process thereof.
  • colloid of a hardly water-soluble metal hydroxide obtained by adjusting the pH of an aqueous solution of a water-soluble polyvalent metallic compound to 7 or higher in particular, colloid of a hardly water-soluble metal hydroxide formed by reacting a water-soluble polyvalent metallic compound with an alkali metal hydroxide in an aqueous phase is preferred.
  • This colloid is used as an aqueous dispersion.
  • the colloid of the hardly water-soluble metal hydroxide used in the present invention preferably has number particle diameter distributions, D 50 (50% cumulative value of number particle diameter distribution) of at most 0.5 ⁇ m and D 90 (90% cumulative value of number particle diameter distribution) of at most 1 ⁇ m. If the particle diameter of the colloid is too great, the stability of the suspension polymerization is broken, and the shelf stability of the resulting polymerized toner is deteriorated.
  • the dispersing agent is generally used in a proportion of 0.1 to 20 parts by weight per 100 parts by weight of the monomer for core. If the amount of the dispersing agent used is too little, it is difficult to achieve sufficient polymerization stability, so that the resulting polymer tends to aggregate. If the amount of the dispersing agent used is too great on the other hand, the effect of the dispersing agent on polymerization stability is saturated, which is uneconomical. In addition, the viscosity of the aqueous dispersion medium becomes too high, resulting in difficulty of forming fine droplets of the liquid mixture.
  • a water-soluble polymer may be used as a dispersing agent as needed.
  • the water-soluble polymer may be mentioned polyvinyl alcohol, methyl cellulose and gelatin.
  • a surfactant may be used for the purpose of stably conducting the suspension polymerization so far as the dependence of the charge properties of the resulting polymerized toner on environment does not become large.
  • radical polymerization initiator may be mentioned water-soluble polymerization initiators, such as persulfates such as potassium persulfate and ammonium persulfate; and azo compounds such as 4,4-azo-bis(4-cyanovaleric acid), 2,2-azobis(2-amidinopropane) bihydrochloride, 2,2-azobis-2-methyl-N-1,1-bis-(hydroxymethyl)-2-hydroxyethylpropionamide, 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile and 1,1'-azobis(1-cyclohexanecarbonitrile); and oil-soluble polymerization initiators, such as peroxides such as methyl ethyl peroxide, di-t-butyl peroxide, acetyl peroxide, dicumyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butyl peroxy-2-e
  • oil-soluble radical initiators are preferred, with oil-soluble radical initiators selected from among organic peroxides whose ten-hour half-life temperatures are 60 to 80°C, preferably 65 to 80°C and whose molecular weights are 250 or lower being particularly preferred.
  • oil-soluble radical initiators t-butyl peroxy-2-ethyl-hexanoate is particularly preferred because the resulting polymerized toner scarcely gives odor upon printing and barely causes environmental destruction by volatile components such as odor.
  • the amount of the polymerization initiator used is generally 0.001 to 3 wt.% based on the aqueous medium. If the amount of the polymerization initiator used is less than 0.001 wt.%, the rate of polymerization becomes slow. If the amount exceeds 3 wt.%, particles having a particle diameter smaller than 1 ⁇ m are formed as a by-product. It is hence not preferable to use the initiator in such a little or great amount.
  • additives such as a molecular weight modifier may be used by mixing them with the polymerizable monomer for core.
  • the molecular weight modifier examples include mercaptans such as t-dodecylmercaptan, n-dodecylmercaptan and n-octylmercaptan; and halogenated hydrocarbons such as carbon tetrachloride and carbon tetrabromide.
  • the molecular weight modifier may be added before the initiation of the polymerization or in the course of the polymerization.
  • the molecular weight modifier is used in a proportion of generally 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight per 100 part by weight of the polymerizable monomer for core.
  • the polyfunctional ester compound also fulfills a function as a parting agent, and so it is not always necessary to use any other parting agent.
  • a parting agent for example, a low molecular weight polyolefin such as low molecular weight polyethylene, low molecular weight polypropylene or low molecular weight polybutylene; or a paraffin wax, may be used within limits not impeding the objects of the present invention.
  • a lubricant such as oleic acid or stearic acid; a dispersion aid such as a silane or titanium coupling agent; and/or the like may also be used with a view toward uniformly dispersing the colorant in the core particles.
  • a lubricant or dispersion aid is generally used in a proportion of about 1/1,000 to 1/1 based on the weight of the colorant.
  • the polymerization for obtaining the core particles is continued until the conversion of the polymerizable monomer into a polymer reaches generally at least 80%, preferably at least 85%, more preferably at least 90%. If the conversion into the polymer is lower than 80%, a great amount of the polymerizable monomer for core remains unreacted, so that each surface of the resultant core particles is covered with a copolymer of the polymerizable monomer for core and a polymerizable monomer for shell even when the polymerizable monomer for shell is added to conduct polymerization. Therefore, a difference in Tg between the core particles and the shell becomes small, and so the shelf stability of the resulting polymerized toner tends to lower.
  • the polymerized toner can be obtained by polymerizing a polymerizable monomer for shell in the presence of the core particles.
  • the polymerizable monomer for shell used in the present invention is such that can form a polymer having a glass transition temperature higher than that of the polymer component making up the core particles.
  • a difference in Tg between the polymer obtained by the polymerizable monomer for shell and the polymer component making up the core particles is relative.
  • the polymerizable monomer for shell there may be used monomers capable of forming a polymer having a glass transition temperature higher than 80°C, for example, styrene and methyl methacrylate, either singly or in combination of two or more monomers thereof.
  • the polymerizable monomer for shell may be such that forms a polymer having a glass transition temperature of 80°C or lower.
  • the glass transition temperature of the polymer formed from the polymerizable monomer for shell must be preset so as to be higher than the glass transition temperature of the polymer component of the core particles.
  • the glass transition temperature of the polymer formed from the polymerizable monomer for shell is preset within a range of generally 50 to 120°C, preferably 60 to 115°C, more preferably 80 to 110°C. If the glass transition temperature of the polymer formed from the polymerizable monomer for shell is too low, the shelf stability of the resulting polymerized toner may be lowered in some cases even if such a glass transition temperature is higher than that of the polymer component of the core particles. In many cases, the glass transition temperature of the polymer component of the core particles may be represented by the calculated Tg of a polymer formed from the polymerizable monomer for core.
  • a difference in glass transition temperature between the polymer formed from the polymerizable monomer for core and the polymer formed from the polymerizable monomer for shell is generally at least 10°C, preferably at least 20°C, more preferably at least 30°C.
  • the polymerizable monomer for shell is preferably polymerized in the presence of the core particles after it is formed into droplets smaller than the number average particle diameter of the core particles in an aqueous dispersion medium. If the droplet diameter of the droplets of the polymerizable monomer for shell is too great, the shelf stability of the resulting polymerized toner shows a tendency to lower.
  • a mixture of the polymerizable monomer for shell and the aqueous dispersion medium is subjected to a finely dispersing treatment by means of, for example, an ultrasonic emulsifier. It is preferred that the aqueous dispersion thus obtained be added to the reaction system in which the core particles are present.
  • the polymerizable monomer for shell is not particularly limited by solubility in water at 20°C.
  • a polymerizable monomer for shell having a high solubility in water specifically, a monomer having a solubility of at least 0.1 wt.% in water at 20°C becomes liable to quickly migrate to the surfaces of the core particles, so that a polymerized toner having good shelf stability is easy to obtain.
  • Examples of the polymerizable monomer for shell having a solubility lower than 0.1 wt.% in water at 20°C include styrene, butyl acrylate, 2-ethylhexyl acrylate, ethylene and propylene.
  • Examples of the polymerizable monomer for shell having a solubility of at least 0.1 wt.% in water at 20°C include (meth)acrylic esters such as methyl methacrylate and methyl acrylate; amides such as acrylamide and methacrylamide; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; nitrogen-containing vinyl compounds such as 4-vinylpyridine; and vinyl acetate and acrolein.
  • an organic solvent preferably used in the case where the polymerizable monomer for shell having a solubility lower than 0.1 wt.% in water at 20°C may be mentioned lower alcohols such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol and butyl alcohol; ketones such as acetone and methyl ethyl ketone; cyclic ethers such as tetrahydrofuran and dioxane; ethers such as dimethyl ether and diethyl ether; and amides such as dimethylformamide.
  • lower alcohols such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol and butyl alcohol
  • ketones such as acetone and methyl ethyl ketone
  • cyclic ethers such as tetrahydrofuran and dioxane
  • ethers such as dimethyl ether and diethyl ether
  • amides such as dimethylformamide.
  • the organic solvent is added in such an amount that the solubility of the polymerizable monomer for shell in the dispersion medium (containing water and the organic solvent in combination) is at least 0.1 wt.%.
  • the specific amount of the organic solvent added varies according to the kind of the organic solvent, and the kind and amount of the polymerizable monomer for shell. However, it is generally 0.1 to 50 parts by weight, preferably 0.1 to 40 parts by weight, more preferably 0.1 to 30 parts by weight per 100 parts by weight of the aqueous dispersion medium. No particular limitation is imposed on the order of addition of the organic solvent and the polymerizable monomer for shell to the reaction system.
  • a monomer having a solubility lower than 0.1 wt.% in water at 20°C and a monomer having a solubility of at least 0.1 wt.% in water at 20°C are used in combination, it is preferable to first add the monomer having a solubility of at least 0.1 wt.% in water at 20°C to polymerize it, then add the organic solvent, and further add the monomer having a solubility lower than 0.1 wt.% in water at 20°C to polymerize it.
  • the Tg of the polymer obtained from the polymerizable monomer for shell, which is polymerized in the presence of the core particles for the purpose of controlling the fixing temperature of the resulting polymerized toner, and the amount of the monomer added can be suitably controlled.
  • the polymerizable monomer for shell is preferably used in combination with a charge control agent.
  • the incorporation of the charge control agent into the shell permits improving the charge properties of the resulting polymerized toner.
  • the charge control agent there may be used various kinds of charge control agents for positive charge and negative charge.
  • the charge control agents may be mentioned Nigrosine NO1 (product of Orient Chemical Industries Ltd.), Nigrosine EX (product of Orient Chemical Industries Ltd.), Spiron Black TRH (product of Hodogaya Chemical Co., Ltd.), T-77 (product of Hodogaya Chemical Co., Ltd.), Bontron S-34 (product of Orient Chemical Industries Ltd.) and Bontron E-84 (product of Orient Chemical Industries Ltd.).
  • the charge control agent is used in a proportion of generally 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight per 100 parts by weight of the polymerizable monomer for core.
  • a process for polymerizing the polymerizable monomer for shell in the presence of the core particles may be mentioned a process in which the polymerizable monomer for shell is added to the reaction system of the polymerization reaction which has been conducted for obtaining the core particles, thereby continuously conducting polymerization, and a process in which the core particles obtained in a separate reaction system are charged, to which the polymerizable monomer for shell is added, thereby conducting polymerization stepwise.
  • the polymerizable monomer for shell may be added to the reaction system in one lot, or continuously or intermittently by means of a pump such as a plunger pump.
  • a water-soluble radical initiator at the time the polymerizable monomer for shell is added. It is considered that when the water-soluble radical initiator is added upon the addition of the polymerizable monomer for shell, the water-soluble initiator enters in the vicinity of each outer surface of the core particles to which the polymerizable monomer for shell has migrated, so that a polymer layer (shell) is easy to form on the core particle surface.
  • water-soluble radical initiator may be mentioned persulfates such as potassium persulfate and ammonium persulfate; azo initiators such as 4,4-azo-bis(4-cyanovaleric acid), 2,2-azobis(2-amidinopropane) bihydrochloride and 2,2-azobis-2-methyl-N-1,1-bis-(hydroxymethyl)-2-hydroxyethylpropionamide; and combinations of an oil-soluble initiator such as cumene peroxide with a redox catalyst.
  • the amount of the water-soluble radical initiator used is generally 0.001 to 1 wt.% based on the aqueous medium.
  • a weight ratio of the polymerizable monomer for core to the polymerizable monomer for shell is generally 40/60 to 99.9/0.1, preferably 60/40 to 99.5/0.5, more preferably 80/20 to 99/1. If the proportion of the polymerizable monomer for shell is too low, the effect of improving the shelf stability becomes little. If the proportion is too high on the other hand, the effects of lowering the fixing temperature and improving the permeability through OHP become little.
  • the polymerized toner according to the present invention is composed of fine spherical particles sharp in particle diameter distribution in which the volume average particle diameter is generally 2 to 20 ⁇ m, preferably 3 to 15 ⁇ m, and the particle diameter distribution (volume average particle diameter/number average particle diameter) is generally at most 1.6, preferably at most 1.5.
  • the polymerized toner according to the present invention is composed of polymer particles of core-shell structure, comprising the core particles and the shell which covers each of the core particles.
  • the average thickness of the shell is generally 0.001 to 1 ⁇ m, preferably 0.005 to 0.5 ⁇ m. If the thickness of the shell is too great, the fixing ability of the toner is deteriorated. If the thickness is too small on the other hand, the shelf stability of the toner is deteriorated.
  • the particle diameters of the core particles and the thickness of the shell in the polymerized toner can be determined by directly measuring the size and shell thickness of each of particles selected at random from electron photomicrographs thereof when they can be observed through an electron microscope.
  • the particle diameters of the core particles and the thickness of the shell are difficult to observe through the electron microscope, the particle diameters of the core particles are measured through the electron microscope in the same manner as described above or by means of a Coulter counter at the stage of formation of the core particles. After the core particles are then covered with the shell, the particle diameters of the resultant polymerized toner particles are measured again through the electron microscope or by means of the Coulter counter, whereby the average thickness of the shell can be found from changes in particle diameter before and after the covering with the shell. When it is difficult to measure the shell thickness by these methods, the thickness of the shell can be calculated out from the particle diameter of the core particles and the used amount of the polymerizable monomer for forming the shell.
  • the polymerized toner according to the present invention contains toluene-insoluble matter in an amount of generally at most 50 wt.%, preferably at most 20 wt.%, more preferably at most 10 wt.%. If the toluene-insoluble matter is contained in plenty, the fixing ability of the polymerized toner shows a tendency to lower.
  • the toluene-insoluble matter is determined by placing a polymer component making up the polymerized toner in a 80-mesh woven metal basket, immersing the basket in toluene for 24 hours at room temperature, drying solids remaining in the basket by a vacuum drier and then measuring the weight of the dry solids to express it in terms of % by weight based on the weight of the polymer component.
  • the polymerized toner according to the present invention has a ratio (rl/rs) of the length (rl) to the breadth (rs) within a range of 1 to 1.2, preferably 1 to 1.15. If the ratio is too high, the resolution of an image formed from such a polymerized toner is deteriorated. In addition, when such a polymerized toner is contained in a toner container in an image forming apparatus, its durability shows a tendency to lower, since friction between particles of the polymerized toner becomes greater, and so external additives such as a flowability improver are separated from the toner.
  • the polymerized toner according to the present invention can be used as a developer as it is. However, it may also be used as a developer with various kinds of additives (external additives) such as a flowability improver added thereto as needed.
  • the additives generally attach to the surface of the polymerized toner.
  • the external additives may be mentioned various kinds of inorganic particles and organic resin particles. Of these, silica particles and titanium oxide particles are preferred, with silica particles subjected to a hydrophobicity-imparting treatment being particularly preferred.
  • the external additives and the polymerized toner are charged into a mixer such as a Henschel mixer to mix them under stirring.
  • the fixing temperature can be lowered to a low temperature of 80 to 150°C, preferably 80 to 130°C.
  • the polymerized toner does not aggregate during its storage and is hence excellent in shelf stability.
  • Image forming apparatus
  • An image forming apparatus to which the polymerized toner according to the present invention is applied, comprises a photosensitive member (photosensitive drum), a means for charging the surface of the photosensitive member, a means for forming an electrostatic latent image on the surface of the photosensitive member, a means for receiving a toner (developer), a means for supplying the toner to develop the electrostatic latent image on the surface of the photosensitive member, thereby forming a toner image, and a means for transferring the toner image from the surface of the photosensitive member to a transfer medium.
  • a photosensitive member photosensitive drum
  • a means for charging the surface of the photosensitive member a means for forming an electrostatic latent image on the surface of the photosensitive member
  • a means for receiving a toner (developer) a means for supplying the toner to develop the electrostatic latent image on the surface of the photosensitive member, thereby forming a toner image
  • a photosensitive drum 1 as the photosensitive member is installed rotatably in the direction of an arrow A.
  • the photosensitive drum 1 has a structure that a photoconductive layer is provided around a peripheral surface of an electroconductive support drum.
  • the photoconductive layer is composed of, for example, an organic photosensitive member, selenium photosensitive member, zinc oxide photosensitive member or amorphous silicon photosensitive member.
  • a charging roll 2 as a charging means, a laser beam irradiating device 3 as a latent image forming means, a developing roll 4 as a developing means, a transfer roll 10 as a transfer means, and optionally a cleaning device (not illustrated) are arranged along the circumferential direction of the drum.
  • the charging roll 2 bears an action that the surface of the photosensitive drum 1 is evenly charged either positively or negatively. Voltage is applied to the charging roll 2, and the charging roll 2 is brought into contact with the surface of the photosensitive drum 1, thereby charging the surface of the photosensitive drum 1.
  • the charging roller 2 may be replaced by a charging means according to corona discharge.
  • the laser beam irradiating device 3 bears an action that light corresponding to image signals is irradiated on the surface of the photosensitive drum 1 to expose the surface of the photosensitive drum 1 evenly charged to the light on the predetermined pattern, thereby forming an electrostatic latent image on the exposed portion of the drum (in the case of reversal development) or forming an electrostatic latent image on the unexposed portion of the drum (in the case of normal development).
  • An example of other latent image forming means includes that composed of an LED array and an optical system.
  • the developing roll 4 bears an action that a toner is applied to the electrostatic latent image formed on the surface of the photosensitive drum 1. Bias voltage is applied between the developing roll 4 and the photosensitive drum 1 in such a manner that the toner is applied only to a light-exposed portion of the photosensitive drum 1 in reversal development, or only to a light-unexposed portion of the photosensitive drum 1 in normal development.
  • the developing roll 4 and a feed roll 6 are arranged in a casing 9 for receiving the toner 7, the developing roll 4 and a feed roll 6 are arranged.
  • the developing roll 4 is arranged in close vicinity to the photosensitive drum 1 in such a manner that a part thereof comes into contact with the photosensitive drum 1, and is rotated in a direction B opposite to the rotating direction of the photosensitive drum 1.
  • the feed roll 6 is rotated in contact with and in the same direction C as the developing roll 4 to supply the toner 7 to the outer periphery of the developing roll 4.
  • An agitating means (agitating blade) 8 for agitating the toner is installed in the casing 9.
  • a blade 5 for developing roll as a layer thickness regulating means is arranged at a position between the contact point with the feed roll 6 and the contact point with the photosensitive drum 1 on the periphery of the developing roll 4.
  • the blade 5 is composed of conductive rubber or stainless steel, and voltage of
  • the polymerized toner 7 according to the present invention is contained in the casing 9 of the image forming apparatus.
  • the polymerized toner 7 may comprise additives such as a flowability improver attached thereto. Since the polymerized toner according to the present invention has a core-shell structure, and the shell of the surface layer is formed of a polymer having a relatively high glass transition temperature, the stickiness of the surface is reduced, and so the polymerized toner is prevented from aggregating during storage in the casing 9. In addition, since the particle diameter distribution of the polymerized toner according to the present invention is relatively sharp, the toner layer formed on the developing roll 4 can be made a substantially single layer by the layer thickness regulating means 5, thereby forming reproducible images with good quality.
  • the transfer roll 10 serves to transfer the toner image formed on the surface of the photosensitive drum 1 by the developing roll 4 to a transfer medium 11.
  • the transfer medium 1 include paper and resin sheets such as OHP sheets.
  • transferring means may be mentioned a corona discharge device and a transfer belt in addition to the transfer roll 10.
  • the toner image transferred to the transfer medium 11 is fixed to the transfer medium by a fixing means.
  • the fixing means is generally composed of a heating means and a press-bonding means. More specifically, the fixing means is generally composed of the combination of a heating roll (fixing roll) 12 and a press roll 13.
  • the transfer medium 11, to which the toner image has been transferred is passed through between the heating roll 12 and the press roll 13 to melt the toner, and at the same time press-bond it to the transfer medium 11, thereby fixing the toner image thereto.
  • the polymerized toner according to the present invention is used as a toner. Therefore, the toner is easily melted even when the heating temperature by the heating means is low, and is fixed to the transfer medium in a flattened state by slightly pressing it by the press-bonding means, so that high-speed printing or copying is feasible. Further, the toner image fixed to an OHP sheet is excellent in permeability through OHP.
  • the cleaning device serves to clean off the toner remaining on the surface of the photosensitive drum 1 without transferring and is composed of, for example, a cleaning blade or the like.
  • the cleaning device is not always required to install in the case where a system that cleaning is conducted by the developing roll 4 at the same time as development is adopted.
  • the polymerized toner according to the present invention is used as the toner.
  • the volume average particle diameter (dv) and particle diameter distribution, i.e., a ratio (dv/dp) of the volume average particle diameter to a number average particle diameter (dp) of polymer particles were measured by means of a Multisizer (manufactured by Coulter Co.). The measurement by the Multisizer was conducted under the following conditions:
  • the volume resistivity of each toner sample was measured by means of a dielectric loss measuring device (TRS-10 Model, trade name; manufactured by Ando Electric Co., Ltd.) under conditions of a temperature of 30°C and a frequency of 1 kHz.
  • TRS-10 Model, trade name manufactured by Ando Electric Co., Ltd.
  • a commercially available printer (4 papers per minute printer) of a non-magnetic one-component development system was modified in such a manner that the temperature of a fixing roll can be varied.
  • This modified printer was used to form an image with each toner sample, thereby evaluating the toner as to the image.
  • a temperature at which a fixing rate of the toner amounted to 80% was defined as a fixing temperature.
  • the fixing test was conducted by varying the temperature of the fixing roll in the printer to determine the fixing rate at each temperature, thereby finding a relationship between the temperature and the fixing rate.
  • the black solid-printed area means an area controlled in such a manner that the toner is caused to adhere to all dots within this area.
  • the peeling operation of the pressure-sensitive adhesive tape is a series of operation that a pressure-sensitive adhesive tape (Scotch Mending Tape 810-3-18, product of Sumitomo 3M Limited) is applied to a measuring area of the test paper sheet to cause the tape to adhere to the sheet by pressing the tape under a fixed pressure, and the adhesive tape is then peeled at a fixed rate in a direction along the paper sheet.
  • the image density was measured by means of a reflection image densitometer manufactured by McBeth Co.
  • the evaluation of shelf stability was conducted by placing each toner sample in a closed container to seal it, sinking the container into a constant-temperature water bath controlled to 50°C and then taking the container out of the water bath after a predetermined period of time went on, thereby measuring the weight of toner aggregated.
  • the sample toner taken out of the container was transferred to a 42-mesh screen so as not to destroy the structure thereof as much as possible, and the screen was vibrated for 30 seconds by means of a powder measuring device, REOSTAT (manufactured by Hosokawa Micron Corporation) with the intensity of vibration preset to 4.5. Thereafter, the weight of the toner remaining on the screen was measured to regard it as the weight of the toner aggregated.
  • the aggregation rate (wt.%) of the toner was calculated out from this weight of the aggregated toner and the weight of the sample.
  • the shelf stability of the toner sample was evaluated by 4 ranks in accordance with the following standard:
  • the temperature of the fixing roll in the modified printer described above was preset to 150°C to conduct printing with each toner sample on a commercially available OHP sheet (Transparency, product of Uchida Yoko Co., Ltd.), thereby evaluating the toner sample as to permeability through OHP. Whether the printed image permeated through the OHP sheet or not was visually observed thereby ranking it as ⁇ where the image permeated, or X where the image did not permeate.
  • the charge level of each toner sample was measured under respective environments of L/L (10°C in temperature and 20% in humidity, RH) and H/H (30°C in temperature and 80% in humidity, RH) to evaluate the toner sample as to charge level under varied environments.
  • the charge level of the toner was determined in the following manner.
  • the toner was charged into a commercially available printer (4 papers per minute printer) under each of the above-described environments and left to stand for 24 hours. Thereafter, a print pattern of half tone was printed 5 times, and the toner on a developing roll was then sucked in a suction type charge level meter to measure a charge level per unit weight from the charge level and weight of the toner sucked at this time.
  • the droplet diameter of droplets of the polymerizable monomer for shell was found to be 1.6 ⁇ m in terms of D 90 as determined by means of a microtrack particle diameter distribution measuring device by adding the droplets at a concentration of 3% to a 1% aqueous solution of sodium hexametaphosphate.
  • the particle diameter distribution of the colloid formed was measured by means of the microtrack particle diameter distribution measuring device (manufactured by Nikkiso Co., Ltd.) and found to be 0.38 ⁇ m in terms of D 50 (50% cumulative value of number particle diameter distribution) and 0.82 ⁇ m in terms of D 90 (90% cumulative value of number particle diameter distribution).
  • the measurement by means of the microtrack particle diameter distribution measuring device was performed under the following conditions:
  • the polymerizable monomer composition for core prepared above was then poured into the colloidal dispersion of magnesium hydroxide obtained above, and the resultant mixture was stirred at 12,000 rpm under high shearing force by means of the TK type homomixer, thereby forming droplets of the polymerizable monomer composition for core.
  • the thus-prepared aqueous dispersion containing droplets of the monomer composition for core was charged into a reactor equipped with an agitating blade to initiate a polymerization reaction at 90°C. At the time a conversion into a polymer reached almost 100%, the polymerizable monomer for shell prepared above and 1 part of a 1% aqueous solution of potassium persulfate were added to continue the reaction for 5 hours. Thereafter, the reaction was stopped to obtain an aqueous dispersion containing polymer particles of core-shell structure.
  • the volume average particle diameter (dv) of core particles measured by taking out them just before the polymerizable monomer for shell was added was 5.7 ⁇ m, and a ratio of the volume average particle diameter (dv) to the number average particle diameter (dp) thereof was 1.32.
  • the resultant polymer particles had a shell thickness of 0.09 ⁇ m and an rl/rs ratio of 1.1 and contained 2% of toluene-insoluble matter.
  • the toner thus obtained was used to measure its fixing temperature. As a result, it was 120°C.
  • the evaluation of image revealed that an image high in image density, free of fog and irregularities, and extremely good in resolution was obtained. The results are shown in Table 1.
  • a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that the amount of pentaerythritol tetrastearate used in Example 1 was changed to 5 parts.
  • the evaluation of image revealed that an image high in image density, free of fog and irregularities, and extremely good in resolution was obtained. The results are shown in Table 1.
  • a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that pentaerythritol tetrastearate used in Example 1 was changed to glycerol triarachidate (purity of arachidic acid: about 60%). The results are shown in Table 1.
  • a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that pentaerythritol tetrastearate used in Example 1 was changed to paraffin wax having a melting point of 60°C. The results are shown in Table 1.
  • a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that pentaerythritol tetrastearate used in Example 1 was changed to low molecular weight polypropylene having a number average molecular weight of 2,200. The results are shown in Table 1. Table 1 Example Comp. Ex.
  • a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that 10 parts of methyl methacrylate used as the polymerizable monomer for shell in Example 1 were changed to 9 parts of methyl methacrylate and 1 part of butyl acrylate.
  • the evaluation results are shown in Table 2.
  • a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that 10 parts of styrene were used in place of 10 parts of methyl methacrylate used as the polymerizable monomer for shell in Example 1, and 20 parts of methanol were added just before the polymerizable monomer for shell was added.
  • the evaluation results are shown in Table 2.
  • a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that 2,2-azobisisobutyronitrile was used in place of t-butyl peroxy-2-ethylhexanoate used as the polymerization initiator for the polymerizable monomer for core in Example 1, and the reaction temperature was changed to 75°C.
  • Table 2 When this developer was used to conduct fixing, slight odor was given off.
  • a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that the polymerizable monomer for shell was added without conducting the treatment by means of the ultrasonic emulsifier in Example 1. The results are shown in Table 2. Table 2 Example Comp. Ex.
  • a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that butyl acrylate used as the polymerizable monomer for core in Example 1 was changed to 2-ethylhexyl acrylate. The results are shown in Table 3.
  • a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that 5 parts of a magenta pigment (Pigment Red 122) were used in place of 7 parts of carbon black used in Example 1. The results are shown in Table 3.
  • a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that 5 parts of a yellow quinophthalone pigment (Pigment Yellow 138) were used in place of 7 parts of carbon black used in Example 1. The results are shown in Table 3.
  • a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that 5 parts of a cyan pigment (Pigment Blue 15:3) were used in place of 7 parts of carbon black used in Example 1. The results are shown in Table 3.
  • a polymerized toner and a developer (toner) were obtained in the same manner as in Comparative Example 1 except that 5 parts of a magenta pigment (Pigment Red 122) were used in place of 7 parts of carbon black used in Example 1. The results are shown in Table 3. Table 3 Example Comp. Ex.
  • a polymerized toner and a developer (toner) were obtained in the same manner as in Example 1 except that pentaerythritol tetramyristate was used in place of pentaerythritol tetrastearate used in Example.
  • the volume average particle diameter (dv) of core particles measured by taking out them just before the polymerizable monomer for shell was added was 5.8 ⁇ m, and a ratio of the volume average particle diameter (dv) to the number average particle diameter (dp) thereof was 1.22.
  • the resultant polymer particles had a shell thickness of 0.09 ⁇ m and an rl/rs ratio of 1.1 and contained 2% of toluene-insoluble matter.
  • the volume resistivity of the non-magnetic one-component developer (toner) obtained by adding colloidal silica subjected to the hydrophobicity-imparting treatment to the polymerized toner was 11.3 log ⁇ cm.
  • the toner was used to measure its fixing temperature. As a result, it was 120°C.
  • the toner had charge levels of -28 ⁇ c/g and -25 ⁇ c/g under L/L and H/H environments, respectively.
  • pentaerythritol tetramyristate was excellent in solubility in the polymerizable monomer compared with pentaerythritol tetrastearate, and so there was no need to grind or melt it in advance for enhancing the solubility at room temperature.
  • polymerized toners which have a low fixing temperature and uniformly melting ability, and moreover are excellent in shelf stability, and a production process thereof.
  • the use of the polymerized toners according to the present invention permits the speeding-up of copying or printing, the formation of full-color images and energy saving.
  • the polymerized toners according to the present invention can form toner images which exhibit excellent permeability when conducting printing on an OHP sheet with such a polymerized toner and fixing the resulting image thereto.
  • the polymerized toners according to the present invention permit the formation of high-quality images without causing fogging and deterioration of image density.
  • an image forming process comprising using the polymerized toner(s) having such excellent various properties, and an image forming apparatus in which the polymerized toner(s) are received.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Developing Agents For Electrophotography (AREA)
EP97909708A 1996-11-06 1997-10-31 Toner encapsule et son procede de production Expired - Lifetime EP0952495B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP08106032A EP2042932A1 (fr) 1996-11-06 1997-10-31 Toner polymérisé et son procédé de production

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP31009196 1996-11-06
JP31009196 1996-11-06
PCT/JP1997/003972 WO1998020396A1 (fr) 1996-11-06 1997-10-31 Toner a base de polymere et procede de production de ce dernier

Related Child Applications (1)

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EP08106032A Division EP2042932A1 (fr) 1996-11-06 1997-10-31 Toner polymérisé et son procédé de production

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EP0952495A1 true EP0952495A1 (fr) 1999-10-27
EP0952495A4 EP0952495A4 (fr) 2000-05-10
EP0952495B1 EP0952495B1 (fr) 2009-01-14

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EP08106032A Withdrawn EP2042932A1 (fr) 1996-11-06 1997-10-31 Toner polymérisé et son procédé de production

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JP (1) JP3670667B2 (fr)
KR (1) KR100533491B1 (fr)
DE (1) DE69739222D1 (fr)
WO (1) WO1998020396A1 (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1258511A2 (fr) * 2001-05-16 2002-11-20 Konica Corporation Particules contenant un colorant et encre à base d'eau comprenant une émulsion de polymère
US6720122B1 (en) * 1999-06-28 2004-04-13 Zeon Corp. Toner for developing static charge image and method for preparation thereof
WO2004090644A1 (fr) * 2003-04-08 2004-10-21 Lg Chem, Ltd Toner a structure double couche ou triple couche
EP1748320A2 (fr) * 2005-07-27 2007-01-31 Samsung Electronics Co., Ltd. Procédé de préparation de l'encre en poudre et encre en poudre préparée utilisant le procédé
US7572564B2 (en) * 2005-10-25 2009-08-11 Fuji Xerox Co., Ltd. Toner for electrostatic image development, electrostatic image developer and image forming method using the same
US7595138B2 (en) 2002-12-10 2009-09-29 Panasonic Corporation Toner, two-component developer, and image forming method
CN1932654B (zh) * 2004-10-05 2010-06-23 柯尼卡美能达商用科技株式会社 静电图像显影用调色剂
US7892716B2 (en) * 2005-09-24 2011-02-22 Samsung Electronics Co., Ltd. Method of preparing core-shell toner and toner prepared using the method
EP3141963A1 (fr) 2015-09-14 2017-03-15 King Abdulaziz City for Science and Technology Matériau de toner polymérisé comprenant des nanoparticules de silicone (si) et procédé de préparation correspondant

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100662914B1 (ko) * 2004-12-16 2007-01-02 삼성전자주식회사 토너 조성물의 제조 방법
JP2006215411A (ja) * 2005-02-04 2006-08-17 Nippon Zeon Co Ltd 静電荷像現像用トナー
KR100703972B1 (ko) * 2006-01-10 2007-04-09 주식회사 씨아이티 중합 토너와 그 제조방법
EP2287673B1 (fr) 2008-05-28 2013-09-25 Canon Kabushiki Kaisha Encre en poudre
JP5445920B2 (ja) * 2009-08-28 2014-03-19 株式会社リコー 静電荷像現像剤用トナー
JP5361984B2 (ja) * 2011-12-27 2013-12-04 キヤノン株式会社 磁性トナー
JP7183679B2 (ja) * 2018-10-10 2022-12-06 日本ゼオン株式会社 重合トナーの製造方法

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GB2097947A (en) * 1981-04-30 1982-11-10 Fuji Photo Film Co Ltd Pressure-fixable eiectrostatographic capsule toner material
GB2109572A (en) * 1981-10-09 1983-06-02 Konishiroku Photo Ind Encapsulated toner for development of electrostatic images
EP0615167A1 (fr) * 1993-03-10 1994-09-14 Kao Corporation Toner encapsulé pour fixation à la chaleur et à la pression et procédé pour sa fabrication
EP0743564A2 (fr) * 1995-05-19 1996-11-20 Canon Kabushiki Kaisha Révélateur pour le développement d'images électrostatiques et procédé pour leur fabrication

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CA1007918A (en) * 1971-12-14 1977-04-05 Joseph H. Moriconi Developer material
CA1122460A (fr) * 1977-05-18 1982-04-27 James W. Consaul Tireuse electrographique comprenant une poudre non aqueuse contenant un liquide
JPS5494035A (en) * 1977-11-17 1979-07-25 Canon Inc Developing toner and method
JPH03136065A (ja) 1989-10-23 1991-06-10 Kao Corp 静電荷像現像用トナー及びその製造方法
JPH04342264A (ja) * 1991-05-20 1992-11-27 Kao Corp 熱圧力定着用カプセルトナー
EP0514843A1 (fr) * 1991-05-20 1992-11-25 Kao Corporation Toner encapsulé pour fixage par chaleur et pression
US5275903A (en) * 1992-05-07 1994-01-04 Xerox Corporation Modified thermotropic liquid crystalline compositions

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GB2097947A (en) * 1981-04-30 1982-11-10 Fuji Photo Film Co Ltd Pressure-fixable eiectrostatographic capsule toner material
GB2109572A (en) * 1981-10-09 1983-06-02 Konishiroku Photo Ind Encapsulated toner for development of electrostatic images
EP0615167A1 (fr) * 1993-03-10 1994-09-14 Kao Corporation Toner encapsulé pour fixation à la chaleur et à la pression et procédé pour sa fabrication
EP0743564A2 (fr) * 1995-05-19 1996-11-20 Canon Kabushiki Kaisha Révélateur pour le développement d'images électrostatiques et procédé pour leur fabrication

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Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6720122B1 (en) * 1999-06-28 2004-04-13 Zeon Corp. Toner for developing static charge image and method for preparation thereof
EP1197804A4 (fr) * 1999-06-28 2004-11-17 Nippon Zeon Co Toner pour developper une image de charge statique et procede de preparation
EP1258511A3 (fr) * 2001-05-16 2003-05-07 Konica Corporation Particules contenant un colorant et encre à base d'eau comprenant une émulsion de polymère
US6777463B2 (en) 2001-05-16 2004-08-17 Konica Corporation Particles containing a colorant and a water-based ink comprising polymer emulsion
EP1258511A2 (fr) * 2001-05-16 2002-11-20 Konica Corporation Particules contenant un colorant et encre à base d'eau comprenant une émulsion de polymère
US7595138B2 (en) 2002-12-10 2009-09-29 Panasonic Corporation Toner, two-component developer, and image forming method
WO2004090644A1 (fr) * 2003-04-08 2004-10-21 Lg Chem, Ltd Toner a structure double couche ou triple couche
US7282312B2 (en) 2003-04-08 2007-10-16 Lg Chem, Ltd. Toner having bi-layer or triple-layer
CN1932654B (zh) * 2004-10-05 2010-06-23 柯尼卡美能达商用科技株式会社 静电图像显影用调色剂
EP1748320A2 (fr) * 2005-07-27 2007-01-31 Samsung Electronics Co., Ltd. Procédé de préparation de l'encre en poudre et encre en poudre préparée utilisant le procédé
EP1748320A3 (fr) * 2005-07-27 2009-04-15 Samsung Electronics Co., Ltd. Procédé de préparation de l'encre en poudre et encre en poudre préparée utilisant le procédé
US7842449B2 (en) 2005-07-27 2010-11-30 Samsung Electronics Co., Ltd. Method of preparing toner and toner prepared using the method
US7892716B2 (en) * 2005-09-24 2011-02-22 Samsung Electronics Co., Ltd. Method of preparing core-shell toner and toner prepared using the method
US7572564B2 (en) * 2005-10-25 2009-08-11 Fuji Xerox Co., Ltd. Toner for electrostatic image development, electrostatic image developer and image forming method using the same
EP3141963A1 (fr) 2015-09-14 2017-03-15 King Abdulaziz City for Science and Technology Matériau de toner polymérisé comprenant des nanoparticules de silicone (si) et procédé de préparation correspondant

Also Published As

Publication number Publication date
EP2042932A1 (fr) 2009-04-01
KR20000053037A (ko) 2000-08-25
KR100533491B1 (ko) 2005-12-06
EP0952495A4 (fr) 2000-05-10
JP3670667B2 (ja) 2005-07-13
DE69739222D1 (de) 2009-03-05
WO1998020396A1 (fr) 1998-05-14
EP0952495B1 (fr) 2009-01-14

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