EP1347342B1 - Toner for electrophotography - Google Patents

Toner for electrophotography Download PDF

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Publication number
EP1347342B1
EP1347342B1 EP03006072A EP03006072A EP1347342B1 EP 1347342 B1 EP1347342 B1 EP 1347342B1 EP 03006072 A EP03006072 A EP 03006072A EP 03006072 A EP03006072 A EP 03006072A EP 1347342 B1 EP1347342 B1 EP 1347342B1
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EP
European Patent Office
Prior art keywords
toner
bisphenol
weight
resin
image
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP03006072A
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German (de)
English (en)
French (fr)
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EP1347342A1 (en
Inventor
Minoru Masuda
Yasuo Asahina
Satoshi Mochizuki
Kazuhiko Umemura
Yasuaki Iwamoto
Hideki Sugiura
Tomomi Tamura
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Ricoh Co Ltd
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Ricoh Co Ltd
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Publication of EP1347342A1 publication Critical patent/EP1347342A1/en
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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
    • G03G9/08784—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775
    • G03G9/08797—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775 characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature
    • 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
    • G03G9/08753—Epoxyresins
    • 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
    • G03G9/08759—Polyethers
    • 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
    • G03G9/08784—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775
    • G03G9/08786—Graft polymers
    • 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
    • G03G9/08784—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775
    • G03G9/08791—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775 characterised by the presence of specified groups or side chains
    • 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
    • G03G9/08784—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775
    • G03G9/08793—Crosslinked polymers
    • 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
    • G03G9/08784—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775
    • G03G9/08795—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775 characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants

Definitions

  • the present invention relates to a toner for electrophotography.
  • a latent electrostatic image is formed on a photoconductor by a conventional method, and developed with a dry toner. Thereafter, the resulting toner image is transferred onto a sheet of copy paper, and is fixed onto the sheet by thermal fixing (generally, using a heat roller) so as to obtain a copy image.
  • the dry toner for this method contains a binder resin and a coloring agent as the main components. If required, the dry toner may further contain additives, such as a charge control agent and an offset-preventing agent.
  • binder resins are polystyrenes, styrene-acrylic copolymers, polyester resins, epoxy resins, in terms of the properties required for the toner, for instance, transparency, insulating properties, water-resistance, flowability (as a powder), mechanical strength, glossiness, thermoplasticity, grindability.
  • styrene resins are widely used because of the excellent grindability, water-resistance, and flowability.
  • a plasticizer contained in the resin sheet, which is formed of the vinyl chloride resin is transferred to the fixed toner image, and plasticizes the fixed toner image.
  • the plasticizer is then fused onto a side of the resin sheet.
  • JP-A Japanese Patent Application Laid-Open
  • 07-77832 discloses the use of a polyol resin synthesized by using an epoxy resin as a raw material.
  • Such a polyol resin uses an epoxy resin and bisphenol A as raw materials.
  • the epoxy groups in the epoxy resin and the active hydrogen moiety of bisphenol A are allowed to react with each other to perform synthesis.
  • Epoxy groups in the epoxy resin are chemically very active, and, biochemically, considered to have a toxicity such as skin irritation. For this reason, for the synthesis of a polyol resin, the number of moles of the active hydrogen atoms is set to be larger than the number of moles of the epoxy groups.
  • US-A-5998073 relates to a dry toner for electrophotography comprising a colorant, a releasing agent, and a polyol resin as a binder resin, wherein the polyol resin is obtained by reacting an epoxy resin, a dihydric phenol, and an alkylene oxide adduct of a dihydric phenol or a glycidyl ether thereof.
  • a polyol resin used in the examples has an epoxy equivalent of 20,000 or more.
  • the present invention provides, in a first aspect, a toner for electrophotography which is characterized by containing a coloring agent and a binder resin.
  • the binder resin is a polyol resin which is prepared by reacting a) a bisphenol-A-type epoxy resin, b) a compound having one or more active hydrogen atoms which react with an epoxy group in molecules of the compound having one or more active hydrogen atoms, and c) a compound having two or more active hydrogen atoms which react with an epoxy group in molecules of the compound having two or more active hydrogen atoms, wherein the compound having two or more active hydrogen atoms which react with an epoxy group in molecules of the compound having two or more active hydrogen atoms comprises bisphenol A, in which a weight concentration of non-reacted bisphenol A in the toner is 1000 ⁇ g/g or less, and the toner has an epoxy equivalent of 20000 or more, measured in accordance with an indicator-titration method defined in paragraph 4.2 of JIS K7236.
  • the present invention also provides, in a second aspect, an image-forming process in which a latent electrostatic image on a latent electrostatic image support is developed by the toner of the present invention.
  • the present invention further provides, in a third aspect, an image-forming apparatus which includes an image developer where the toner of the present invention is utilized as a developer.
  • the present invention still further provides, in a fourth aspect, an image-forming process cartridge.
  • the image-forming process cartridge of the present invention includes an image developer configured to supply a developer onto a latent electrostatic image so as to visualize and develop the latent electrostatic image.
  • the image-forming process cartridge of the present invention is formed in one-piece construction, and is attachable to and detachable from an image-forming apparatus.
  • the developer in the image-forming process cartridge of the present invention contains the toner of the present invention.
  • FIGURE is a diagram showing one example of the image-forming process cartridge of the present invention.
  • the toner for electrophotography of the present invention contains a coloring agent and a binder resin, and if required, other materials may be added thereto.
  • a polyol resin according to present claim 1 is used as the binder resin.
  • the polyol resin to be used in the present invention is synthesized in the following manner.
  • a compound having active hydrogen atoms which react with epoxy groups is used as a raw material.
  • This compound and an epoxy resin are allowed to react with each other so that the resulting reaction product has a linear chain or network molecular structure.
  • a compound having two or more active hydrogen atoms which react with an epoxy group in molecules of the compound having two or more active hydrogen atoms is used as a raw material to enlarge the molecule.
  • a compound having one or more active hydrogen atoms which react with an epoxy group in molecules of the compound having one or more active hydrogen atoms is used to cap the end of the resin molecule, thereby preventing the resin molecule from increasing in size.
  • any bisphenol-A-type epoxy resin may be used in the present invention so long as it has two or more epoxy bonds.
  • the bisphenol A-type epoxy resins expressed by the following Formula (2) are typical ones. These are low priced and readily available also on a chemical industrial scale, and also chemically stable. '
  • such an epoxy resin obtained by bonding the bisphenol such as bisphenol A with epichlorohydrin is used in part, because it favorably results in a low cost. wherein "n" expresses 0 or more.
  • the epoxy resin to be used in the present invention is preferably obtained by bonding bisphenol A with epichlorohydrin.
  • the epoxy resin includes at least two or more kinds of bisphenol A-type epoxy resin components having different number-average molecular weights.
  • the number-average molecular weight of the low molecule weight is 360 to 2000
  • the number-average molecular weight of the high molecule weight is 3000 to 10,000.
  • the content of the low molecule weight is 20 % by weight to 50 % by weight relative to the amount of the polyol resin
  • the content of the high molecule weight is 5 % by weight to 40 % by weight, relative to the amount of the polyol resin.
  • Examples of the compound having one active hydrogen atom which reacts with an epoxy group in the molecule to be used in the present invention may include monovalent phenols, secondary amines, carboxylic acid, and the like.
  • Examples of the monovalent phenols include phenol, cresol, isopropylphenol, aminophenol, nonylphenol, dodecylphenol, xylenol, p-cumylphenol.
  • Examples of the secondary amines include diethylamine, dipropylamine, dibutylamine, N-methyl(ethyl)piperazine, piperazine.
  • Examples of the carboxylic acids include propionic acid, caproic acid, benzoic acid, stearic acid.
  • bisphenol A is excellent in terms of cost, and enables improving the chemical resistance of the toner resin. Furthermore, the use of bisphenol A also perfectly prevents toners from being transferred onto a vinyl chloride resin sheet.
  • the amount of residual bisphenol A in the toner which has been suspected of an endocrine disrupting chemical in recent years, is set to be 1000 ⁇ g/g or less from the viewpoint of the safety of the toner.
  • a description will be given to a process for reducing the amount of residual bisphenol A.
  • the one containing bisphenol A as the skeleton is used, when considering the chemical resistance.
  • the amount of residual bisphenol A is also possible to set the amount of residual bisphenol A at 1000 ⁇ g/g or less, by using bisphenol A. This can be achieved by making the number of epoxy groups in the epoxy resin equal to the number of active hydrogen atoms which react with epoxy groups with high accuracy.
  • the number of epoxy groups is set to be larger than the number of active hydrogen atoms which react with epoxy groups, bisphenol A having active hydrogen atoms will not remain alone, but epoxy groups will remain in the resin.
  • the epoxy groups are chemically active, and considered to have a toxicity such as skin irritation.
  • the number of active hydrogen atoms which react with epoxy groups has been set to be larger than the number of epoxy groups, so that no epoxy groups remain.
  • the compounds such as bisphenol A having active hydrogen atoms will remain in a slight amount.
  • the present invention by making the number of epoxy groups in the epoxy resin equal to the number of active hydrogen atoms which react with epoxy groups with high accuracy, it is possible to eliminate epoxy groups in the polyol resin, and to control the amount of residual bisphenol A to 1000 ⁇ g/g or less.
  • the raw materials are weighed with high accuracy, and that sufficient stirring is performed and sufficient time is taken for the reaction so as to leave no reaction residue.
  • the weight concentration of the polar solvent soluble component of the present invention can be determined by, for example, the high performance liquid chromatography (HPLC) as shown below. There is also another method for determining the concentration by a gas chromatography. However, HPLC is preferred in terms of accuracy.
  • a sample is dissolved in a toner-soluble or resin-soluble solvent (for example, tetrahydrofuran (THF), toluene, methylethylketone, dichloromethane, chloroform).
  • a polar solvent such as methanol, or the like (for example, methanol, ethanol, n-propanol, acetonitrile, water, or a mixed solution thereof), is added, thereby forming a precipitate.
  • a polar solvent such as methanol, or the like (for example, methanol, ethanol, n-propanol, acetonitrile, water, or a mixed solution thereof)
  • any of the techniques are not limited to the following apparatus and conditions, so long as it is capable of analyzing the polar solvent soluble matter with high accuracy.
  • the polyol resin to be used in the present invention employs an epoxy resin as a raw material.
  • the polyol resin has no epoxy group because the epoxy group is chemically very active, and biochemically considered to have a toxicity such as skin irritation.
  • the polyol resin of the present invention refers to a polyol resin which has an epoxy skeleton, but has no terminal epoxy substantially.
  • the epoxy equivalent is used for expressing the number of epoxy groups.
  • the term, "epoxy equivalent,” refers to the equivalent weight per epoxy group (g/equiv.). The value obtained by dividing the average molecular weight by the number of epoxy groups per molecule.
  • the epoxy equivalent is determined in accordance with an indicator titration method defined in paragraph 4.2 of JIS K 7236. However, the epoxy equivalent has an identification limit of about 20,000. Thus, if it is 20,000 or more, it is considered that there are almost no epoxy groups.
  • the toner of the present invention shows excellent image-fixing properties, and prevents curling on a fixed image.
  • methods for introducing the material obtained by adding an alkylene oxide to bisphenol include the following two methods.
  • the first method is a method using a product of epoxidation reactive between the bisphenol-alkylene oxide adduct and epichlorohydrin.
  • the reaction product is used as an epoxy resin for synthesizing a polyol resin.
  • dihydric phenol-alkylene oxide adduct examples include reaction products of ethylene oxide, propylene oxide, butylene oxide, or mixture thereof, and bisphenol such as bisphenol A, bisphenol B. Further, the adduct thus obtained may also be glycidylated with epichlorohydrin or ⁇ -methylepichlorohydrin.
  • the dihydric phenol-alkylene oxide adduct or a diglycidyl ether thereof is preferably contained in an amount of 10 to 40 % by weight relative to the amount of the polyol resin. If the content of the dihydric phenol-alkylene oxide adduct is low, the toner resin itself has no flexibility, and, unfavorably, a printed copy paper tends to curl increasingly, the toners are insufficiently fixed onto a copy paper, or other deficiencies occur. If "n + m" is equal to 9 or more, or the content is too high, the image transferred from the copy fixed image side to the vinyl chloride resin sheet may become more likely to occur, too much glossiness may occur, and further the storageability may deteriorate.
  • the second method is a method using a compound prepared by ester-bonding a polyvalent carboxylic acid to the dihydric phenol-alkylene oxide adduct such as bisphenol A as a compound having two or more active hydrogen atoms which react with an epoxy group in molecules of the compound having two or more active hydrogen atoms.
  • polyvalent carboxylic acids may include malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, phthalic acid, terephthalic acid, trimellitic acid, trimellitic anhydride.
  • the compound prepared by allowing the dihydric phenol-alkylene oxide adduct and a polyvalent carboxylic acid to react is preferably contained in an amount of 10 % by weight to 40 % by weight relative to the amount of the polyol resin. If the content thereof is low, the toner resin itself has no flexibility, a printed copy paper is more likely to curl, and, unfavorably, the toners are insufficiently fixed onto paper, or other deficiencies occur. If "n + m" is equal to 7 or more, or the content is too high, the image is transferred from a side on which the image is fixed, to the vinyl chloride resin sheet may become more likely to occur, too much glossiness may occur, and further the storageability may deteriorate.
  • the Tg of the resulting resin is preferably from 50°C to 70 °C, and more preferably from 55°C to 70 °C. If the Tg is low, agglomerate tends to occur in a toner bottle or a development unit. As a result, the agglomerate is also developed. The developed agglomerate remains on the photoconductor, and leaves one or more white spots on an image, when the toners are transferred. On the other hand, if the Tg is high, unfavorably, image glossiness tends to be insufficient.
  • any known dyes and pigments can be used as the coloring agents.
  • the coloring agent include carbon black, nigrosine dyes, black oxide of iron, Naphthol Yellow S, Hansa Yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, yellow ochre, chrome yellow, titanic yellow, polyazo yellow, oil yellow, Hansa Yellow (GR, A, RN, R), Pigment Yellow L, benzidine yellow (G, GR), permanent yellow (NCG), vulcan fast yellow (5G, R), tartrazine lake, quinoline yellow lake, anthragen yellow BGL, isoindolinone yellow, red oxide, red lead oxide, red lead, cadmium red, cadmium mercury red, antimony red, permanent red 4R, para red, Fire Red, para-chloro-ortho-nitroaniline red, Lithol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD
  • the coloring agent is preferably used in an amount of 0.1 part by weight to 50 parts by weight relative to 100 parts by weight of the binder resin.
  • a so-called release agent for imparting the releasability to the toner may also be used.
  • the softening point of the release agent to be used is preferably 70°C to 100 °C.
  • the softening point of lower than 70 °C results in deficient storage stability.
  • the softening point is higher than 100 °C, not only the image-fixing properties tend to deteriorate, but also the resulting color image tends to be poor in quality because of its lower glossiness.
  • the release agent may include synthesized waxes such as low-molecular weight polyethylene, low-molecular weight polypropylene, copolymers thereof, vegetable waxes such as candelilla wax, carnauba wax, rice wax, Japan tallow, jojoba wax, or the like; animal waxes such as bees wax, lanolin, spermaceti, or the like; mineral waxes such as montan wax, ozocerite and grease waxes such as hardened castor oil, hydroxystearic acid, aliphatic acid amide, phenol aliphatic aid ester. From the viewpoint of chemical structures of the waxes, hydrocarbon waxes, ester waxes, amide waxes are known. However, in the present invention, ester waxes are preferable from the viewpoint of evaluating the storageability, image quality, the range of the fixing temperature.
  • vegetable waxes such as candelilla wax, carnauba wax, rice wax, Japan tallow, jojoba wax,
  • the amount of the release agent is preferably 1 part by weight to 6 parts by weight relative to the total amount of the toner.
  • the toner If the amount is larger than 6 parts by weight, the toner shows deficient storage stability, rough surface of an image, and lower glossiness. Further, even if the amount is less than 1 part by weight, the surface of an image tends to be rough, and the resulting color image tends to be poor in quality because of the lower glossiness.
  • the toner of the present invention may contain a charge control agent, if required.
  • a charge control agent Any known charge control agents can be used in the present invention.
  • the charge control agent include a nigrosine dye, a triphenylmethane dye, a chromium-containing metal complex dye, a molybdic acid chelate pigment, a rhodamine dye, an alkoxyamine, a quaternary ammonium salt (including a fluorine-modified quaternary ammonium salt), alkylamide, a simplex or a compound of phosphorus, a simplex or a compound of tungsten, a fluorine-containing activator, a metallic salt of salicylic acid, a metallic salt of a salicylic acid derivative.
  • the toner of the present invention may further contain other additives, for example; silica fine particles, aliphatic metallic salts (such as zinc stearate, aluminum stearate. metallic oxides (such as titanium oxide, aluminum oxide, tin oxide, antimony oxide), fluoropolymers.
  • silica fine particles such as zinc stearate, aluminum stearate.
  • metallic oxides such as titanium oxide, aluminum oxide, tin oxide, antimony oxide
  • fluoropolymers such as hydrophobilized silica, titania, and alumina fine particles are preferred.
  • silica fine particles may include HDK H 2000, HDK H 2000/4, HDK H 2050EP, and HDK H 1303VP (all of which are manufactured by Clariant Ltd.), and R972, R974, RX200, RY200, R202, R805, and R812 (all of which are manufactured by Nippon Aerosil K.K.).
  • examples of the titania fine particles may include P-25 (manufactured by Nippon Aerosil K.K.), STT-30, and STT-65C-S (all of which are manufactured by Titan Kogyo K.K.), TAF-140 (manufactured by Fuji Titanium Industry Co., Ltd.), and MT-150W, MT-500B, MT-600B (all of which are manufactured by Tayca Corp.).
  • hydrophobically treated titanium oxide fine particles there can be used the anatase type or rutile type crystalline ones, or amorphous ones.
  • examples thereof may include T-805 (manufactured by Nippon Aerosil K.
  • MT-100S, MT-100T, MT150A, MT150AFM, and MT-150AI all of which are manufactured by Tayca Corp.
  • STT-30A, STT-65S-S all of which are manufactured by Titan Kogyo K.K.
  • TAF-500T and TAF-1500T all of which are manufactured by Fuji Titanium Industry Co., Ltd.
  • MT-100S and MT-100T all of which are manufactured by Tayca Corp.
  • IT-S manufactured by Ishihara Sangyo Kaisha, Ltd.
  • the hydrophobically treated silica fine particles, titania fine particles, or alumina fine particles can be obtained by treating hydrophilic fine particles with a silane coupling agent such as methyl trimethoxy silane, methyl triethoxy silane, octyl trimethoxy silane.
  • a silane coupling agent such as methyl trimethoxy silane, methyl triethoxy silane, octyl trimethoxy silane.
  • an alphilic acid metal salt such as zinc stearate or aluminum stearate
  • a metal oxide such as alumina, tin oxide, or antimony oxide
  • fluoropolymers such as alumina, tin oxide, or antimony oxide
  • the toner made of the materials as described above of the present invention may be used as a double-component developer in combination with a carrier shown below. Alternatively, the toner may be used alone as a single-component developer.
  • developer herein refers to any kinds of agent used for developing a latent electrostatic image.
  • the carrier when the toner is used as a double-component developer, as the carrier, the same materials as those employed in the related art such as iron powders, ferrite particles, glass beads, or the like can be employed. It is noted that these carrier may be coated with a resin. Known resins may also be used in this case. Examples of the resin may include acrylic resin, polyfluorocarbon, polyvinyl chloride, polyvinylidene chloride, phenolic resin, polyvinyl acetal, silicone resin.
  • the mixing ratio of the toner to the carrier in general, it is proper that the toner is mixed in an amount of 2.5 parts by weight to 8.0 parts by weight relative to 100 parts by weight of the carrier.
  • the softening point and the Tg of the resin for use in the present invention are determined in the following manner.
  • the measurement is carried out using a full-automatic dropping point measurement apparatus "FP5/FP53" manufactured by Mettler Co., Ltd., as an apparatus for determining the softening point in accordance with the following procedure:
  • the measurement is carried out, using DSC-200 made by Seiko Instruments Inc., as an apparatus for determining the Tg in accordance with the following procedure:
  • the sample is heated from room temperature up to 150 °C with a temperature increasing rate of 20 °C/min, and is then allowed to stand at 150 °C for 10 minutes.
  • the sample is then cooled to 0 °C at a temperature decreasing rate of 50 °C/min, and is then allowed to stand for 10 minutes.
  • the sample is again heated up to 150 °C with a temperature increasing rate of 20 °C/min, and subjected to the DSC measurement.
  • the Tg is measured by reading a peak rise-up temperature, using an analysis software "Tg Job.”
  • the epoxy equivalent is measured in accordance with an indicator titration method defined in paragraph 4.2 of JIS K7236.
  • An image-forming process of the present invention has no particular restriction, except that the toner for electrophotography of the present invention is used for developing a latent electrostatic image, and can be appropriately selected according to the intended purpose.
  • the image-forming apparatus of the present invention has no particular restriction, except that the image-forming apparatus accommodates an image developer in which the toner for electrophotography of the present invention is provided as a developing unit.
  • image developer herein refers to a developing device that enables developing a latent electrostatic image with a developer.
  • the image-forming process cartridge of the present invention is characterized by including a latent electrostatic image support; a charger configured to charge a surface of the latent electrostatic image support; a light-irradiator configured to irradiate a light to the latent electrostatic image; a cleaner configured to clean the surface of the latent electrostatic support; and an image developer configured to supply a developer onto a latent electrostatic image so as to develop the latent electrostatic image and to form a visible image.
  • the image-forming process cartridge is formed in one-piece construction, and is attachable to and detachable from an image-forming apparatus.
  • the image developer in the image-forming process cartridge of the present invention includes the developer which contains the toner for electrophotography including a color toner for forming an image according to the present invention.
  • the image-forming process cartridge When installed in an image-forming apparatus, the image-forming process cartridge provides sufficient offset-resistance even in a fixing step where no lubricant oil is coated on a fixing roller, or a very small amount of lubricant oil is coated on a fixing roller.
  • FIGURE shows an example of a structure of an image-forming process unit (process cartridge) (106), which includes all of a photoconductive drum (101) as the latent electrostatic image support, a charging roller (103) as the charger, a cleaning unit (105) as the cleaner, and a developing unit (102) as the image developer.
  • the image-forming process cartridge is attachable to and detachable from a printer.
  • the developing unit includes a developing sleeve (104).
  • the mixture was polymerized at a reaction temperature of 180 °C for 6 to 9 hours, resulting in about 1 kg of a polyol resin having a softening point of 108 °C and a Tg of 61 °C (which may be referred to as "resin 1,” hereinafter).
  • the amount of residual bisphenol A was found to be 0 ⁇ g/g, and the epoxy equivalent was found to be 20,000 or more.
  • the resulting mixture was further heated to 160 °C, and xylene was distilled off under a reduced pressure.
  • the mixture was polymerized at a reaction temperature of 180 °C for 6 to 9 hours, resulting in about 1 kg of a polyol resin with a softening point of 107 °C and a Tg of 58 °C (which may be referred to as "resin 2,” hereinafter).
  • the amount of the residual bisphenol A was found to be 830 ⁇ g/g, and the epoxy equivalent was found to be 20,000 or more.
  • reaction 3 a polyol resin with a softening point of 109 °C and a Tg of 58 °C (hereinafter, may be referred to as "resin 3").
  • the amount of residual bisphenol A was found to be 280 ⁇ g/g, and the epoxy equivalent was found to be 20,000 or more.
  • the resulting mixture was heated to 70 °C to 100 °C under a N 2 atmosphere, and 0.183 g of lithium chloride was added thereto.
  • the resulting mixture was further heated to 160 °C, and xylene was distilled off under a reduced pressure.
  • the mixture was polymerized at a reaction temperature of 180 °C for 6 to 9 hours, resulting in about 1 kg of a polyol resin with a softening point of 109 °C and a Tg of 58 °C (hereinafter, may be referred to as "resin 4").
  • the amount of residual bisphenol A was found to be 950 ⁇ g/g, and the epoxy equivalent was found to be 20,000 or more.
  • the resulting mixture was heated to 70 °C to 100 °C under a N 2 atmosphere, and 0.183 g of lithium chloride was added thereto.
  • the resulting mixture was further heated to 160 °C, and xylene was distilled off under a reduced pressure.
  • the mixture was polymerized at a reaction temperature of 180 °C for 6 to 9 hours, resulting in about 1 kg of a polyol resin with a softening point of 112 °C and a Tg of 59 °C (hereinafter, may be referred to as "resin 6").
  • the amount of residual bisphenol A was found to be 620 ⁇ g/g, and the epoxy equivalent was found to be 20,000 or more.
  • reaction 7 a polyol resin with a softening point of 118 °C and a Tg of 62 °C (hereinafter, may be referred to as "resin 7").
  • the amount of residual bisphenol A was found to be 0 ⁇ g/g, and the epoxy equivalent was found to be 20,000 or more.
  • reaction 8 a polyol resin with a softening point of 108 °C and a Tg of 61 °C (hereinafter, may be referred to as "resin 8").
  • the amount of residual bisphenol A was found to be 0 ⁇ g/g, and the epoxy equivalent was found to be 9380.
  • the resulting mixture was heated to 70 °C to 100 °C under a N 2 atmosphere, and 0.183 g of lithium chloride was added thereto.
  • the resulting mixture was further heated to 160 °C, and xylene was distilled off under reduced pressure.
  • the mixture was polymerized at a reaction temperature of 180 °C for 6 to 9 hours, resulting in about 1 kg of a polyol resin with a softening point of 112 °C and a Tg of 59 °C (hereinafter, may be referred to as "resin 9").
  • the amount of residual bisphenol A was found to be 8850 ⁇ g/g, and the epoxy equivalent was found to be 20,000 or more.
  • the resulting mixture was heated to 70 °C to 100 °C under a N 2 atmosphere, and 0.183 g of lithium chloride was added thereto.
  • the resulting mixture was further heated to 160 °C, and xylene was distilled off under a reduced pressure.
  • the mixture was polymerized at a reaction temperature of 180 °C for 6 to 9 hours, resulting in about 1 kg of a polyol resin with a softening point of 112 °C and a Tg of 59 °C (hereinafter, may be referred to as "resin 10").
  • the amount of residual bisphenol A was found to be 120 ⁇ g/g, and the epoxy equivalent was found to be 9800.
  • a mixture of the materials above was melt-kneaded by a hot roll mill. After cooling the mixture, the resulting mixture was roughly ground in a hammer mill, and then finely pulverized in an air-jet grinder. The resulting fine powder was classified to form a matrix toner having an average particle diameter of about 7 ⁇ m.
  • Each of the toners of Examples 1 to 4 was obtained in the same manner as in the Reference Example, except that the resin was altered to each of the resins of Synthetic Examples 2 to 5 in the Reference Example.
  • a toner of Comparative Example 4 was obtained with in the same manner as in the Reference Example, except that the resin of the Reference Example was altered to a polyester resin.
  • the polyester resin is a resin obtained from the condensation polymerization of a bisphenol A ethylene oxide adduct, a bisphenol A propylene oxide adduct, a terephthalic acid, and a fumaric acid in a molar ratio of 60 : 40 : 25 : 75.
  • the polyester resin has a softening point of 107 °C and a Tg of 59°C.
  • Each of the toners of the Reference Example, Examples 1 to 4, and the toners of Comparative Examples 1 to 4 was installed into a color copier Imagio Color 2800 manufactured by Ricoh Company Ltd., to produce image-bearing copy sheets.
  • Each of the image-bearing copy sheets was brought in intimate contact with a vinyl chloride sheet, and then stored at 50 °C for 1 week to evaluate the adhesion of the toner to the vinyl chloride sheet.
  • Curl of the paper was also evaluated as to the toners of the Reference Example, Examples 1 to 4 and the toners of Comaprative Examples 1 to 4.
  • the curl of the paper was measured based upon how the paper became curled up, when an image with 1mg/cm of the toners was transferred, and was then fixed onto paper.
  • the evaluation was ranked as follows:
  • each of the toners of Examples of the present invention is characterized in that the amount of the residual bisphenol A is smaller, the epoxy equivalent is larger, and less toners adheres to the vinyl chloride sheet, compared with the toners of Comparative Examples.
  • the toner for electrophotography of the present invention enables obtaining a toner which contains less the residual bisphenol A and less residual epoxy groups. Hence the toner for electrophotography of the present invention enables obtaining a safer toner. Further, the toner for electrophotography of the present invention enables obtaining a toner which is less likely to adhere a vinyl chloride mat when used in a copied image.

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Developing Agents For Electrophotography (AREA)
EP03006072A 2002-03-20 2003-03-19 Toner for electrophotography Expired - Lifetime EP1347342B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2002077856A JP3867900B2 (ja) 2002-03-20 2002-03-20 電子写真用トナー
JP2002077856 2002-03-20

Publications (2)

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EP1347342A1 EP1347342A1 (en) 2003-09-24
EP1347342B1 true EP1347342B1 (en) 2011-08-03

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EP03006072A Expired - Lifetime EP1347342B1 (en) 2002-03-20 2003-03-19 Toner for electrophotography

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EP (1) EP1347342B1 (ja)
JP (1) JP3867900B2 (ja)
AT (1) ATE519143T1 (ja)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7291435B2 (en) 2002-03-25 2007-11-06 Sanyo Chemical Industries, Ltd. Toner binder for electrophotography and toner for electrophotography
JP2007156168A (ja) * 2005-12-06 2007-06-21 Kao Corp イエロートナー

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL7605372A (nl) * 1976-05-20 1977-11-22 Oce Van Der Grinten Nv Tonerpoeder voor het ontwikkelen van elektro- statische beelden.
JP3313895B2 (ja) * 1993-07-12 2002-08-12 株式会社リコー 乾式電子写真用トナー
US5998073A (en) 1997-03-10 1999-12-07 Ricoh Company, Ltd. Dry toner for electrophotography
JPH1184719A (ja) * 1997-07-10 1999-03-30 Ricoh Co Ltd 乾式電子写真用トナー
EP1043630B1 (en) * 1999-04-08 2006-01-11 Ricoh Company, Ltd. Toner, method of producting the toner, image formation method using the toner, and toner container

Also Published As

Publication number Publication date
ATE519143T1 (de) 2011-08-15
EP1347342A1 (en) 2003-09-24
JP2003280262A (ja) 2003-10-02
JP3867900B2 (ja) 2007-01-17

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