EP0690354A2 - Procédé de développement pour contact - Google Patents

Procédé de développement pour contact Download PDF

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Publication number
EP0690354A2
EP0690354A2 EP95304501A EP95304501A EP0690354A2 EP 0690354 A2 EP0690354 A2 EP 0690354A2 EP 95304501 A EP95304501 A EP 95304501A EP 95304501 A EP95304501 A EP 95304501A EP 0690354 A2 EP0690354 A2 EP 0690354A2
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EP
European Patent Office
Prior art keywords
resin
positive charging
toner
side chain
group
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.)
Withdrawn
Application number
EP95304501A
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German (de)
English (en)
Other versions
EP0690354A3 (fr
Inventor
Kazushige C/O Mita Industrial Co. Ltd. Inoue
Yoshihisa C/O Mita Industrial Co. Ltd. Kuramae
Takashi C/O Mita Industrial Co. Ltd. Nagai
Tohru C/O Mita Industrial Co. Ltd. Takatsuna
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kyocera Mita Industrial Co Ltd
Original Assignee
Mita Industrial Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mita Industrial Co Ltd filed Critical Mita Industrial Co Ltd
Publication of EP0690354A2 publication Critical patent/EP0690354A2/fr
Publication of EP0690354A3 publication Critical patent/EP0690354A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—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
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/06—Developing
    • G03G13/08—Developing using a solid developer, e.g. powder developer
    • 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
    • G03G9/08702—Binders for toner particles comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08706—Polymers of alkenyl-aromatic compounds
    • G03G9/08708—Copolymers of styrene
    • G03G9/08711—Copolymers of styrene with esters of acrylic or methacrylic acid

Definitions

  • the present invention relates to a method for contact type development using a positive charging toner and a positive charging photoconductor, which is used for image forming apparatus such as facsimiles, laser beam printers, etc.
  • a toner is positively charged by friction with a developing sleeve, to which a negative developing bias has been applied, in a developing apparatus, and then adhered on the surface of the developing sleeve by an image force from a control blade to form an uniform thin layer of the positive charging toner on the surface of the developing sleeve.
  • the surface of a photoconductor is uniformly charged to the same polarity (positive) as that of the toner by corona charging, etc.. Then, the photoconductor is exposed to laser light, etc. to form an electrostatic latent image. Regarding this electrostatic latent image, the potential of the exposed area should be lower than a developing bias and the potential of the non-exposed area should be higher than the developing bias.
  • the toner does not transfer to the photoconductor at the non-exposed area.
  • the toner transfers from the thin layer to the surface of the photoconductor by the potential different from the developing bias, thereby forming a toner image on the surface of the photoconductor.
  • the method for contact type development had the following problem. That is, the potential of the photoconductor is higher than the developing bias at the non-exposed area, as described above, so that an electric charge having a reverse polarity (negative) from the developing sleeve flows into the toner to reverse the charged potential to negative from positive, and the toner of which charged potential is reversed is adhered to the non-exposed area of the photoconductor by the action of the image force, thereby causing so-called image fog, that is, a toner is adhered to the area where no image is formed.
  • the method has also the following problem. That is, when the negative electric charge from the developing sleeve flows into the thin layer, the charged potential of the toner does not reverse but the amount of charging is decreased, thereby decreasing the potential difference between the toner and photoconductor at the exposed area, which results in decrease of the density at the image area of the image formed.
  • It is a main object of the present invention is to provide a method for contact type development which can form a good image having a high image density without causing image fog.
  • the present inventors have studied intensively about an optimum combination of a positive charging toner and a positive charging photoconductor to be used for the method for contact type development.
  • a positive charging toner wherein a resin having a trialkylammonio group at the side chain (hereinafter referred to as an "electric charge controlling resin”) is blended as an electric charge controlling material, with a positive charging photoconductor wherein a single-layer type positive charging organic photosensitive layer is formed on the surface of an electroconductive substrate, a good image having a high image density can be obtained without causing image fog.
  • the method for contact type development of the present invention comprises the steps of: rubbing a positive charging toner with a developing surface, preferably a sleeve, to which a developing bias is applied, to positively charge the toner, thereby forming a uniform thin layer of the positive charging toner on the developing surface; charging the surface of a positive charging photoconductor to the same polarity as that of the toner and exposing to light to form an electrostatic latent image having a potential lower than the developing bias; bringing the thin layer of the positive charging toner on the developing surface into contact with the electrostatic latent image on the surface of the photoconductor to transfer the toner from the thin layer to the surface of the photoconductor, thereby forming a toner image on the surface of the photoconductor; and transferring the toner image to a material to be printed; wherein the positive charging toner contains an electric charge controlling resin as an electric charge controlling material, and the positive charging photoconductor comprises an electroconductive substrate and a single-layer type positive charging organic photo
  • the electric charge controlling resin wherein a trialkylammonio group is introduced into the side chain has a good compatibility with a fixing resin so that it does not collect on the surface or interior of a toner particle like a normal low-molecular weight electric charge controlling material, for example, dye type electric charge controlling material such as nigrosine dye, etc., but is uniformly dispersed in the toner particle. Therefore, the positive charging toner using the electric charge controlling resin as the electric charge controlling material is superior in charging stability and the negative electric charge from the developing sleeve is not easily flown into so that the charging potential thereof is not easily allowed to reverse from positive to negative or the amount of changing is not easily decreased.
  • a normal low-molecular weight electric charge controlling material for example, dye type electric charge controlling material such as nigrosine dye, etc.
  • the positive charging toner using the electric charge controlling resin matches well with the single-layer type positive charging organic photosensitive layer formed on the surface of the electroconductive substrate with respect to charging characteristics, etc., so that the toner is efficiently transferred to the exposed area on the surface of the photoconductor from the thin layer on the surface of the developing sleeve, but no toner is transferred at the non-exposed area.
  • a good image having a high image density can be formed without causing image fog.
  • Fig. 1 is a schematic diagram illustrating the apparatus used for measuring a fog density in the Examples of the present invention.
  • Fig. 2 is a graph illustrating a relation between the charged potential and the fog density of the surface of the photoconductor measured using the apparatus of Fig. 1 .
  • the positive charging toner to be used in the present invention is that which contains the electric charge controlling resin, wherein a trialkylammonio group is introduced into the side chain, as the electric charge controlling material.
  • the positive charging toner is composed of a toner particle formed by internally adding the electric charge controlling resin and a colorant in a fixing resin, and an external additive (e.g. inorganic fine powder, etc.) to be externally added in the toner particle.
  • the external additive may be used for improving fluidity and the like.
  • the fixing resin examples include styrene resin (homopolymer or copolymer containing styrene or a styrene substitute) such as polystyrene, chloropolystyrene, poly- ⁇ -methylstyrene, styrene-chlorostyrene copolymer, styrenepropylene copolymer, styrene-butadiene copolymer, styrenevinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylate copolymer (e.g.,
  • styrene-methyl acrylate copolymer styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styreneoctyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.
  • styrene-methacrylate copolymer e.g.
  • styrene-methyl methacrylate copolymer styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-phenyl methacrylate copolymer, etc.
  • styrene- ⁇ -chloromethyl acrylate copolymer styrene-acrylonitrile-acrylate copolymer, etc.
  • polyvinyl chloride low-molecular weight polyethylene, low-molecular weight polypropylene, ethylene-ethyl acrylate copolymer, polyvinyl butyral, ethylene-vinyl acetate copolymer, rosin-modified maleic resin, phenol resin, epoxy resin, polyester resin, ionomer resin, polyurethane resin, silicone resin, ketone resin, xylene resin, polyamide resin and the like. These may be used alone or in combinations thereof.
  • the colorant to be contained in the toner particle there can be used various dyes, pigments, etc. which have hitherto been known. Among them, carbon black is mainly used in case of a black toner.
  • carbon black there can be used various carbon blacks which have hitherto been known, such as channel black, roller black, disk black, gas furnace black, oil furnace black, thermal black, acetylene black and the like.
  • the amount of carbon black is not specifically limited. However, since carbon black itself has an electroconductivity, it also plays a role as a control means of electric properties of the toner particle, which take part in charging of the toner particle. Accordingly, it is preferred to set the preferable range of the amount to be added according to the objective performances of the developer.
  • the amount of carbon black to be formulated is preferably about 1 to 9 parts by weight, based on 100 parts by weight of the fixing resin, in view of the charging properties of the developer.
  • an electric charge controlling resin wherein a trialkylammonio group corresponding to a quaternary ammonium salt is introduced into the side chain, as described above.
  • the electric charge controlling resin include compounds wherein a trialkylammonio group represented by the formula: (wherein R1, R and R3 are the same or different and indicate a straight or branched chain alkyl group having 1 to 6 carbon atoms, such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group or hexyl group; and X is F, Cl, Br, I, ClO4, PF4 or BF4) as the side chain is introduced into a suitable polymer main chain.
  • the main chain of the electric charge controlling resin there can be used various polymer main chains.
  • the compatibility between the electric charge controlling resin and fixing resin is particularly important in view of charging properties of the toner so that it is preferred to use the polymer main chain having a good compatibility with the polymer to be used as the fixing resin. Among them, it is more preferred to use the same polymer main chain as the polymer to be used as the fixing resin.
  • the styrene-acrylic resin such as styrene-acrylate copolymer, styrene-methacrylate copolymer, etc.
  • the main chain is the styreneacrylic resin
  • the trialkylammonio group is substituted on whole or partial ester moiety of acrylate or methacrylate. It is preferable that the portion of acrylate or methacrylate component in styrene-acrylic resin is 10 to 50 mol %.
  • Examples of the side chain may be a carbon chain such as methyl group, ethyl group, as well as the ester moiety of acrylate or methacrylate.
  • the electric charge controlling resin may be formulated in the amount of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the fixing resin.
  • additives such as release agents (anti-offset agents), etc. may be added to the toner particle, in addition to the colorants and electric charge controlling materials.
  • release agent examples include aliphatic hydrocarbons, aliphatic metal salts, higher fatty acids, fatty acid esters or partially saponified material thereof, silicone oil, various waxes and the like.
  • aliphatic hydrocarbons having a weight-average molecular weight of about 1000 to 10000 are preferred.
  • examples thereof include low-molecular weight polypropylene, low-molecular weight polyethylene, paraffin wax, low-molecular weight olefin polymer of an olefin unit having not less than 4 carbon atoms, and they may be suitably used alone or in combination thereof.
  • the release agent may be internally added in the amount of 0.1 to 10 parts by weight, preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the fixing resin.
  • the toner particle can be produced by uniformly melting and kneading a mixture, obtained by uniformly premixing the above respective components with a dry-blender, Henschel mixer, ball mill, etc., using a kneading apparatus such as Banbury mixer, roll, single- or twin-screw extruder, etc., cooling the resulting kneaded mixture, followed by pulverizing and optional classifying. It can also be produced by a suspension polymerization method.
  • the particle size of the toner particle is not more than 10 ⁇ m for the purpose of enhancing the image quality of the image to be formed.
  • the construction of the present invention can also be used for a normal toner particle having a particle size of larger than 10 ⁇ m.
  • the external additive to be externally added to the toner particle there can be used various external additives which have hitherto been used, such as inorganic fine powder, fluorine plastic particle and the like.
  • silica surface treatments containing hydrophobic or hydrophilic silica fine particles e.g. ultrafine particulate silica anhydride, colloidal silica, etc. are suitably used.
  • the amount of the external additive to be externally added is not specifically limited and it may be the same as a conventional amount.
  • the positive charging photoconductor to be used in combination with the positive charging toner is composed by forming the single-layer type positive charging organic photosensitive layer on the surface of the electroconductive substrate.
  • Such a single-layer type positive charging organic photosensitive layer may be composed by formulating the electric charge generating material and electric charge transferring material in the layer of the binding resin.
  • binding resin examples include synthetic resins which have hitherto been known, such as styrene polymer, acrylic polymer, styrene, acrylic copolymer, ethylene, vinyl acetate copolymer, olefin polymer (e.g. polypropylene, ionomer, etc.), polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, epoxy resin, polycarbonate, polyarylate, polysulfon, diaryl phthalate, silicone resin, ketone resin, polyvinyl butyral, polyether, phenol resin, photosetting resin (e.g. epoxy acrylate, etc.). These binding resins can be used alone or in combination thereof.
  • styrene polymer acrylic polymer, styrene, acrylic copolymer, polyester, alkyd resin, polycarbonate, polyacrylate and the like.
  • bisphenol type polycarbonates derived from bisphenols represented by the formula (2): (wherein R4 and R5 are the same or different and indicate a hydrogen atom or a lower alkyl group such as methyl group, ethyl group and the like; and R4 and R5 may be bonded together with a carbon atom of the main chain to form a cyclo ring such as cyclohexane ring) and phosgene can be used, most preferably.
  • Examples of the electric charge generating material to be contained in the layer of the binding resin include selenium, selenium-tellurium, amorphous-silicon, pyrylium salt, azo pigments, bisazo pigments, anthanthrone pigments, phthalocyanine pigments, indigo pigments, therene pigments, toluidine pigments, pyrazoline pigments, perylene pigments, quinacridone pigments and the like. They may be used alone or in combination thereof so that the resulting photoconductor may have a sensitivity within a desired absorption wavelength range.
  • phthalocyanine pigments e.g. X-type metal-free phthalocyanine, oxotitanylphthalocyanine, etc.
  • perylene pigments represented by the formula (3): (wherein R6 and R7 are the same or different and respectively indicate an alkyl, cycloalkyl, aryl or aralkyl group having not more than 18 carbon atoms which may have a substituent) are particularly preferred.
  • Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, 2-ethylhexyl group and the like.
  • Examples of the cycloalkyl group include cyclohexyl group and the like.
  • Examples of the aryl group include phenyl group, napthyl group, tolyl group xylyl group, ethylphenyl group and the like.
  • Examples of the aralkyl group include benzyl group, phenethyl group and the like.
  • substituents which may be substituted on these groups include lower alkyl groups such as methyl group, ethyl group, etc.; alkoxy groups such as methoxy group, ethoxy group, etc.; halogen atoms such as chlorine, iodine, bromine, etc.
  • the electric charge transferrinq material preferably includes an electron transferring material superior in electric transferring properties and a hole transferring material superior in hole transferring properties.
  • the electron transferring material include electron attractive materials such as paradiphenoquinone derivative, benzoquinone derivative, naphthoquinone derivative, trinitrofluorenoneimine derivative, tetracyanoethylene, tetracyanoquinodimethane, chloroanil, bromoanil, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4,7-trinitro-9-dicyanomthylenefluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, etc., high-molecular compounds of electron attractive materials mentioned above, and the like.
  • paradiphenoquinone derivatives represented by the formula (4): (wherein R8, R9, R10 and R11 are the same or different and indicate a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkoxy group) are suitably used.
  • unsymmetrical paradiphenoquinone derivatives such as paradiphenoquinone derivatives wherein two substituents of the substituents R8, R9, R10 and R11 indicate a lower straight-chain alkyl group and other two substituents indicate a branched alkyl, cycloalkyl, aryl or aralkyl group are used, most preferably, because they are superior in electron transferring properties and solubility to the binding resin.
  • alkyl group examples include the respective groups described above.
  • examples of the hole transferring material include the following compounds: pyrene, N-ethylcarbazole, N-isopropylcarbazole, N-methyl-N-phenylhydrizino-3-methylidene-9-carbazole, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-10-ethylphenothiazine N,N-diphenylhydrazino-3-methylidene-10-ethylphenoxazine; hydrazone salts such as p-diethylaminobenzaldehyde-N,N-diphenylhydrazone, p-diethylaminobenzaldehyde- ⁇ -naphthyl-N-phenylhydrazone, p-pyrrolidinobenzaldehyde-N,N-diphenyl
  • alkyl, cycloalkyl, aryl and aralkyl group examples include the respective groups described above.
  • examples of the acyl group include formyl group, acetyl group, propionyl group, butyryl group, valeryl group and the like.
  • examples of the alkylene group include ethylene group, propylene group, butylene group and the like.
  • the amount of the electric charge generating material is not specifically limited, but is preferably about 0.1 to 5 % by weight, particularly about 0.25 to 2.5 % by weight, based on the total amount (total amount of solid content) of the respective components constituting the single-layer type positive charging organic photosensitive layer.
  • the amount of the electron transferring material is preferably about 5 to 50 % by weight, particularly about 10 to 40 % by weight, based on the total amount of the solid content.
  • the amount of the hole transferring material is preferably about 5 to 50 % by weight, particularly about 10 to 40 % by weight, based on the total amount of the solid content. It is preferred to contain the electron transferring material and hole transferring material in the weight ratio of 1:9 to 9:1, particularly 2:8 to 8:2.
  • the single-layer type positive charging organic photosensitive layer is formed as follows. That is, the above respective components are dispersed/mixed with a suitable solvent using a roll mill, a ball mill, an atriter, a paint shaker, a supersonic dispenser, etc. to prepare a coating solution for photosensitive layer, which is applied on the surface of an electroconductive substrate by a dip coating method, a bar coating method, a spray coating method, a flow coating method, spin coating method, etc., followed by drying.
  • the concentration of the solid content of the coating solution can be suitably adjusted according to the method of coating onto the surface of the electroconductive substrate, and is preferably 5 to 50 % by weight.
  • additives such as antioxidants, radical scavengers, singlet quenchers, ultraviolet absorbers, softeners, surface modifiers, antifoamers, bulking agents, thickners, dispersion stabilizers, wax, acceptors, donors, etc. can be appropriately contained in the coating solution, in addition to the above respective components, within such a range as not to exert a deleterious influence on characteristics of the photoconductor.
  • the durability of the photosensitive layer can be improved without exerting a deleterious influence on characteristics of the photoconductor.
  • the conductive substrate there can be used any substrate of various materials having the electroconductivity in various forms which fit to the structure of an image forming apparatus, such as drum, plate, sheet, etc.
  • the material for the electroconductive substrate include metals or alloy such as aluminum, copper, tin, platinum, gold, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, indium, stainless steel, brass, etc.; plastic materials vapor-deposited or laminated with the above metal; glass materials coated with aluminum iodide, tin oxide, indium oxide, etc.
  • aluminum particularly aluminum which has been subjected to anodizing so that the anodized film may become 1 to 50 ⁇ m, because no interference fringe is produced occurs.
  • the solvent for preparing the coating solution there can be used various organic solvents, and examples thereof include alcohols such as methanol, ethanol, isopropanol, butanol, etc.; aliphatic hydrocarbons such as n-hexane, octane, cyclohexane, etc.; aromatic hydrocarbons such as benzene, toluene, xylene, etc.; halogenated hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene, etc.; ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, etc.; ketones such as acetone, methyl ethyl ketone, cyclohexanone, etc.; esters such as ethyl acetate, methyl acetate, etc.; dimethylformamide, dimethyl
  • a styrene-acrylic resin as the fixing resin 100 Parts by weight of a styrene-acrylic resin as the fixing resin, 7.5 parts by weight of an electric charge controlling resin [resin (trade name of FCA-201-PZ manufactured by Fujikura Kasei Co., Ltd.) wherein a trialkylammonio group is introduced into the side chain of the styrene-acrylic resin)], 5 parts by weight of carbon black as the colorant and 2.5 parts by weight of polypropylene wax as the release agent were mixed and, after melting and kneading, the mixture was pulverized and classified to prepare a toner particle having an average particle size of 9 ⁇ m.
  • an electric charge controlling resin [resin (trade name of FCA-201-PZ manufactured by Fujikura Kasei Co., Ltd.) wherein a trialkylammonio group is introduced into the side chain of the styrene-acrylic resin)]
  • carbon black as the colorant
  • metal-free phthalocyanine as the electric charge generating material
  • 40 parts by weight of N,N'-diphenyl-N,N'-bis(2,4-dimethylphenyl)benzidine as the hole transferring material
  • 40 parts by weight of 3,3',5,5'-tetraphenyldiphenoquinone as the electron transferring material
  • 100 parts by weight of polycarbonate as the binding resin were mixed and dispersed with 800 parts by weight of dichloromethane as the solvent using a paint shaker to prepare a coating solution.
  • this coating solution was applied on an aluminum tube by a dip coating method, followed by hot-air drying in a dark place at 60 °C for 60 minutes to produce a positive charging photoconductor drum having a single-layer type positive charging organic photosensitive layer of 15 ⁇ m in film thickness.
  • an image forming apparatus using a contact type developing apparatus 4 equipped with a developing sleeve 2 and a control blade 3 in combination with transfer and release chargers 5 , 6 was used for the positive charging photoconductor drum 1 produced above in order to carry out the test.
  • a positive charging toner 7 was charged in the developing apparatus 4 and a DC voltage (developing bias) of -200 to -900 V was applied from a bias power 9 to the developing sleeve 2 while rotating the drum 1 and developing sleeve 2 at the state where the drum 1 is grounded (0 V) to produce a potential difference between them.
  • a DC voltage developing bias
  • Example 1 wherein the positive charging toner produced in the production of the positive charging toner I was used in combination with the positive charging photoconductor drum having the positively charged type organic photosensitive layer and the fog density was increased to cause image fog in other combinations, at the state corresponding to the non-exposed area at the time of contact developing where the effective potential difference between the drum 1 and sleeve 2 was 400 V or more.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Developing Agents For Electrophotography (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
  • Dry Development In Electrophotography (AREA)
  • Photoreceptors In Electrophotography (AREA)
EP95304501A 1994-06-29 1995-06-27 Procédé de développement pour contact Withdrawn EP0690354A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP147285/94 1994-06-29
JP6147285A JPH0815893A (ja) 1994-06-29 1994-06-29 接触現像方法

Publications (2)

Publication Number Publication Date
EP0690354A2 true EP0690354A2 (fr) 1996-01-03
EP0690354A3 EP0690354A3 (fr) 1996-08-28

Family

ID=15426751

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95304501A Withdrawn EP0690354A3 (fr) 1994-06-29 1995-06-27 Procédé de développement pour contact

Country Status (2)

Country Link
EP (1) EP0690354A3 (fr)
JP (1) JPH0815893A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0778503A3 (fr) * 1995-12-08 1999-05-12 Brother Kogyo Kabushiki Kaisha Dispositif de formation d'images électrophotographiques avec toner à chargement positif
EP1273976A4 (fr) * 2000-02-10 2004-12-15 Zeon Corp Toner pour le developpement d'images electrostatique et son procede de production

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1010784A (ja) * 1996-06-27 1998-01-16 Brother Ind Ltd 正帯電性一成分現像剤並びにその現像剤を用いた画像形成装置

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60229035A (ja) * 1984-04-27 1985-11-14 Canon Inc 現像方法
US4833059A (en) * 1986-03-18 1989-05-23 Kabushiki Kaisha Toshiba Developing method using one-component non-magnetic toner with positive frictional charge
JPH01193871A (ja) * 1988-01-29 1989-08-03 Toshiba Corp 現像剤

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0778503A3 (fr) * 1995-12-08 1999-05-12 Brother Kogyo Kabushiki Kaisha Dispositif de formation d'images électrophotographiques avec toner à chargement positif
EP1273976A4 (fr) * 2000-02-10 2004-12-15 Zeon Corp Toner pour le developpement d'images electrostatique et son procede de production
US6887637B2 (en) 2000-02-10 2005-05-03 Zeon Corporation Toner for electrostatic image development and process for producing the same

Also Published As

Publication number Publication date
JPH0815893A (ja) 1996-01-19
EP0690354A3 (fr) 1996-08-28

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