JP2013167768A - Photoreceptor, image forming apparatus, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoreceptor that has excellent wear resistance, scratch resistance, and reproducibility of fine dots, and can suppress an increase in residual potential; an image forming apparatus including the photoreceptor; and a process cartridge.SOLUTION: A photoreceptor 10 includes a charge generating layer 12a, a charge transport layer 12b, and a protective layer 13 that are sequentially laminated on a conductive support 11. The protective layer 13 contains a binder resin, spherical particles, and needle-shaped particles; the total content of the spherical particles and the needle-shaped particles is 5 mass% or more and 40 mass% or less; and the mass ratio of the spherical particles relative to the needle-shaped particles is 2 or more and 5 or less.

Description

  The present invention relates to a photoreceptor, an image forming apparatus, and a process cartridge.

  Conventionally, as a photoreceptor, a photoconductive resin type typified by poly-N-vinylcarbazole (PVK), a charge transfer complex type typified by PVK-TNF (2,4,7-trinitrofluorenone), phthalocyanine Organic pigments of the pigment dispersion type typified by a binder and the functional separation type using a combination of a charge generation material and a charge transport material are known.

  In recent years, it has been required to improve the wear resistance of the photoreceptor as the speed and size of the electrophotographic process are increased.

  Patent Document 1 discloses an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support. At this time, the surface layer of the photosensitive layer is a cross-linked resin layer obtained by curing at least a trifunctional or higher-functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure. Filler fine particles are dispersed.

  Patent Document 2 discloses an image carrier having at least a photosensitive layer on a conductive support. At this time, the surface layer of the photosensitive layer has a surface layer, the surface layer is dispersed with needle-like fine particles, and at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerization having a charge transport structure. It is the crosslinked resin layer which hardened the ionic compound.

  However, it is desired to further improve the wear resistance, scratch resistance and reproducibility of fine dots, and to further suppress the increase in residual potential.

  SUMMARY OF THE INVENTION In view of the above-described problems of the prior art, the present invention provides a photoconductor excellent in wear resistance, scratch resistance and reproducibility of fine dots, and capable of suppressing an increase in residual potential, and an image forming apparatus having the photoconductor And it aims at providing a process cartridge.

  In the photoreceptor of the present invention, a photosensitive layer and a protective layer are sequentially laminated on a conductive support, and the protective layer includes a binder resin, spherical particles, and acicular particles, and the spherical particles and the acicular shape. The total content of the particles is 5% by mass or more and 40% by mass or less, and the mass ratio of the spherical particles to the acicular particles is 2 or more and 5 or less.

  The image forming apparatus of the present invention comprises the photosensitive member of the present invention, a charging unit for charging the photosensitive member, an exposure unit for exposing the charged photosensitive member to form an electrostatic latent image, and the photosensitive member. Developing means for developing the electrostatic latent image formed with toner to form a toner image, transfer means for transferring the toner image formed on the photoreceptor to a recording medium, and a toner image transferred to the recording medium It has fixing means for fixing.

  The process cartridge of the present invention has the photoreceptor of the present invention and is detachable from the main body of the image forming apparatus.

  According to the present invention, there are provided a photoconductor that is excellent in wear resistance, scratch resistance, and fine dot reproducibility, and that can suppress an increase in residual potential, and an image forming apparatus and a process cartridge having the photoconductor. Can do.

It is a fragmentary sectional view showing an example of the structure of the photoconductor of the present invention. It is a fragmentary sectional view which shows the other example of the structure of the photoconductor of this invention. It is a fragmentary sectional view which shows the other example of the structure of the photoconductor of this invention. 1 is a schematic diagram illustrating an example of an image forming apparatus of the present invention. It is the schematic which shows the other example of the image forming apparatus of this invention. It is the schematic which shows an example of the process cartridge of this invention.

  Next, the form for implementing this invention is demonstrated with drawing.

  FIG. 1 shows an example of the structure of the photoreceptor of the present invention. In the photoreceptor 10, a charge generation layer 12a, a charge transport layer 12b, and a protective layer 13 are sequentially laminated on a conductive support 11, and the protective layer 13 includes a binder resin, spherical particles, and acicular particles.

  The total content of spherical particles and acicular particles in the protective layer 13 is 5 to 40% by mass, and preferably 10 to 30% by mass. When the total content of the spherical particles and the acicular particles in the protective layer 13 is less than 5% by mass, the abrasion resistance and scratch resistance of the photoconductor 10 are lowered, and when it exceeds 40% by mass, the photoconductor 10 remains. As the potential increases, the reproducibility of the fine dots decreases.

  The mass ratio of the spherical particles to the acicular particles is 2 to 5, and 3 to 4 are preferable. When the mass ratio of the spherical particles to the acicular particles is less than 2, the abrasion resistance and scratch resistance of the photoreceptor 10 and the reproducibility of the fine dots are lowered, and when it exceeds 5, the scratch resistance of the photoreceptor 10 is lowered. .

  The spherical particles mean particles whose primary particle aspect ratio is 1 or more and less than 2, and the acicular particles mean particles whose primary particle aspect ratio is 2 or more and 500 or less.

  The spherical particles are not particularly limited, but spherical fluorine resin particles such as spherical polytetrafluoroethylene particles, spherical resin particles such as spherical silicone resin particles; spherical copper particles, spherical tin particles, spherical aluminum particles, spherical indium particles, etc. Spherical metal particles, spherical silica particles, spherical tin oxide particles, spherical zinc oxide particles, spherical titanium oxide particles, spherical indium oxide particles, spherical antimony oxide particles, spherical bismuth oxide particles, antimony doped spherical tin oxide particles, tin doped Inorganic particles such as spherical metal oxide particles such as spherical indium oxide particles, spherical potassium titanate particles, and spherical a-carbon particles may be used, and two or more kinds may be used in combination. Among these, spherical inorganic particles are preferable, spherical metal oxide particles are more preferable, and spherical aluminum oxide particles are particularly preferable from the viewpoint of wear resistance of the photoreceptor 10.

  The average primary particle size of the spherical particles is usually 0.01 to 0.5 μm. When the average primary particle size of the spherical particles is less than 0.01 μm, the wear resistance and scratch resistance of the photoreceptor 10 may be reduced, and when it exceeds 0.5 μm, the light transmittance of the protective layer 13 is reduced. Sometimes.

  The acicular particles are not particularly limited, but acicular titanium oxide particles, acicular zinc oxide particles, acicular tin oxide particles, acicular silicon oxide particles, acicular zirconium oxide particles, acicular potassium titanate particles, acicular particles Examples thereof include acicular inorganic particles such as indium oxide particles and acicular aluminum oxide particles, and two or more of them may be used in combination. Among these, from the viewpoint of scratch resistance of the photoreceptor 10, acicular inorganic particles are preferable, and acicular metal oxide particles are more preferable.

  The length of the short axis of the acicular particles is usually 0.5 μm or less, and the length of the long axis of the acicular particles is usually 10 μm or less. When the length of the short axis of the acicular particles exceeds 0.5 μm, the light transmittance of the protective layer 13 may decrease. When the length of the long axis of the acicular particles exceeds 10 μm, the photoconductor 10 is scratched. May decrease.

  In addition, the shape of spherical particles and acicular particles can be observed using SEM or TEM.

  The binder resin is not particularly limited, but ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene. , Polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylpentene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, Examples thereof include polyvinylidene chloride and epoxy resin, and two or more kinds may be used in combination. Of these, polycarbonate and polyarylate are preferable.

  The binder resin preferably contains a cross-linked resin. Thereby, the abrasion resistance of the photoreceptor 10 can be improved.

  The binder resin includes a compound having no charge transporting structure and having three or more radical polymerizable groups and a resin having a charge transporting structure and a compound having one radical polymerizable group crosslinked. More preferably.

  The protective layer 13 containing such a binder resin has no charge transporting structure, a compound having three or more radical polymerizable groups, and a compound having a charge transporting structure and one radical polymerizable group. It can be formed by applying a coating liquid containing, and then crosslinking by applying energy.

  The coating liquid may further contain a polymerization initiator as necessary.

  The coating solution may further contain a solvent as necessary.

  The solvent is not particularly limited, but alcohol solvents such as methanol, ethanol, propanol and butanol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; tetrahydrofuran, Ether solvents such as dioxane and propyl ether; halogen solvents such as dichloromethane, dichloroethane, trichloroethane and chlorobenzene; aromatic solvents such as benzene, toluene and xylene; cellosolv solvents such as methyl cellosolve, ethyl cellosolve and cellosolve acetate 2 or more may be used in combination.

  Examples of the method for applying the coating solution include a dip coating method, a spray coating method, a bead coating method, and a ring coating method.

  Examples of the energy applied at the time of crosslinking include heat, light, and radiation. Of these, heat or light is preferable because of easy control of the crosslinking reaction and simplicity of the apparatus.

  Examples of the heating method include a method of heating from the surface side on which the coating liquid is applied or the conductive support 11 side using a gas such as air or nitrogen, steam, a heat medium, infrared rays, or electromagnetic waves. .

  The temperature to heat is 100-170 degreeC normally. When the heating temperature is less than 100 ° C., the crosslinking reaction may not proceed sufficiently, and when it exceeds 170 ° C., the crosslinking reaction may proceed non-uniformly.

  In addition, in order to advance a crosslinking reaction uniformly, after heating at the temperature below 100 degreeC, you may heat at the temperature of 100 degreeC or more.

  Examples of the light source for irradiating light include an ultraviolet light source such as a high-pressure mercury lamp and a metal halide lamp, and a visible light source.

The amount of light to be irradiated is usually 50 to 1000 mW / cm ² . If the amount of light to be irradiated is less than 50 mW / cm ² , the crosslinking reaction may not proceed sufficiently, and if it exceeds 1000 mW / cm ² , the crosslinking reaction may proceed non-uniformly.

  Examples of radiation include electron beams.

  Next, as a compound having no charge transporting structure and having three or more radical polymerizable groups, a compound having three acryloyloxy groups, having a charge transporting structure, and one radical polymerizable group The case of using a coating liquid that contains a triarylamine compound having one acryloyloxy group as the compound having a polymerization initiator and a solvent will be described.

  The mass of the triarylamine compound having one acryloyloxy group with respect to the compound having three acryloyloxy groups is usually 3/7 to 7/3.

  The ratio of the mass of the polymerization initiator to the total mass of the triarylamine compound having 1 acryloyloxy group with respect to the compound having 3 acryloyloxy groups is usually 0.03 to 0.20.

  For example, when the protective layer 13 is formed on the charge transport layer 12b containing a triarylamine compound and a polycarbonate using a spray coating method, examples of the solvent include tetrahydrofuran, 2-butanone, and ethyl acetate.

  The ratio of the mass of the solvent to the total mass of the triarylamine compound having one acryloyloxy group with respect to the compound having three acryloyloxy groups is usually from 3 to 10.

  The thickness of the protective layer 13 is usually 1.0 to 6.0 μm. If the thickness of the protective layer 13 is less than 1.0 μm, the wear resistance of the photoreceptor 10 may be reduced. If the thickness exceeds 6.0 μm, the residual potential of the photoreceptor 10 may increase or fine dots may be formed. The reproducibility may decrease.

The conductive support 11 is not particularly limited as long as the volume resistivity is 1 × 10 ¹⁰ Ω · cm or less, but a metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, or platinum, tin oxide A film or cylindrical plastic or paper coated with a metal oxide such as indium oxide by vapor deposition or sputtering; aluminum plate, aluminum alloy plate, nickel plate, stainless steel plate, etc .; aluminum, aluminum alloy, After making nickel, stainless steel, etc. into a raw pipe by extruding, drawing, etc., pipes subjected to surface treatment such as cutting, superfinishing and polishing can be used.

  Moreover, as the electroconductive support body 11, an endless nickel belt and an endless stainless steel belt can also be used.

  Furthermore, as the conductive support 11, a support in which a conductive layer in which conductive particles are dispersed in a binder resin is formed can also be used.

  Although it does not specifically limit as electroconductive particle, Metal particles, such as carbon black, acetylene black, aluminum particle, nickel particle, iron particle, nichrome particle, copper particle, zinc particle, silver particle, electroconductive tin oxide particle, ITO particle And metal oxide particles.

  The binder resin is not particularly limited, but polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, Polyvinyl acetate, polyvinylidene chloride, polyarylate, phenoxy resin, polycarbonate, cellulose acetate, ethyl cellulose, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly (N-vinylcarbazole), acrylic resin, silicone resin, epoxy resin, melamine resin, A urethane resin, a phenol resin, an alkyd resin, etc. are mentioned.

  The conductive layer can be formed by applying a coating solution in which a binder resin and conductive particles are dispersed in a solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.

  When the support is cylindrical, use a heat shrinkable tube containing a resin such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark), and conductive particles. A conductive layer may be formed.

  The charge generation layer 12a includes a charge generation material, and further includes a binder resin as necessary.

  The charge generation material is not particularly limited, but is a monoazo pigment, disazo pigment, trisazo pigment, perylene pigment, perinone pigment, quinacridone pigment, quinone condensed polycyclic compound, squalic acid dye, other phthalocyanine pigment, Naphthalocyanine pigments, azulenium salt dyes and the like may be mentioned, and two or more may be used in combination. Of these, azo pigments and / or phthalocyanine pigments are preferable.

  Azo pigments have the general formula

（式中、Ｒ_１及びＲ_２は、それぞれ独立に、水素原子、ハロゲン原子、アルキル基、アルコキシ基又はシアノ基であり、Ｃｐ_１及びＣｐ_２は、それぞれ独立に、一般式

Wherein R ₁ and R ₂ are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a cyano group, and Cp ₁ and Cp ₂ are each independently a general formula

（式中、Ｒ_３は、水素原子、メチル基、エチル基等のアルキル基又はフェニル基等のアリール基であり、Ｒ_４、Ｒ_５、Ｒ_６、Ｒ_７及びＲ_８は、それぞれ独立に、水素原子、ニトロ基、シアノ基、フッ素原子、塩素原子、臭素原子、ヨウ素原子等のハロゲン原子、トリフルオロメチル基、メチル基、エチル基等のアルキル基、メトキシ基、エトキシ基等のアルコキシ基、ジアルキルアミノ基又は水酸基であり、Ｚは、置換基により置換されていてもよい芳香族炭素環又は置換基により置換されていてもよい芳香族複素環を構成するのに必要な原子群である。）
で表される化合物であることが好ましい。

(Wherein R ₃ is a hydrogen atom, an alkyl group such as a methyl group or an ethyl group, or an aryl group such as a phenyl group, and R ₄ , R ₅ , R ₆ , R ₇ and R ₈ are each independently Hydrogen atom, nitro group, cyano group, fluorine atom, chlorine atom, bromine atom, halogen atom such as iodine atom, alkyl group such as trifluoromethyl group, methyl group, ethyl group, alkoxy group such as methoxy group, ethoxy group, It is a dialkylamino group or a hydroxyl group, and Z is an atomic group necessary for constituting an aromatic carbocycle which may be substituted with a substituent or an aromatic heterocycle which may be substituted with a substituent. )
It is preferable that it is a compound represented by these.

  The phthalocyanine pigment is preferably titanyl phthalocyanine, and has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.514Å) of CuKα. More preferred is phthalocyanine.

  The binder resin is not particularly limited, but polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly (N-vinylcarbazole), polyacrylamide. , Polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone and the like.

  The mass ratio of the binder resin to the charge generating material is usually 0 to 5, and preferably 0.1 to 3.

  The charge generation layer 12a is formed by applying a coating solution in which a charge generation material is dispersed in a solvent using a ball mill, an attritor, a sand mill, an ultrasonic wave, or the like together with a binder resin as necessary. After coating, it can be formed by drying.

  Examples of the solvent include, but are not limited to, isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin and the like. Of these, ketone solvents, ester solvents, and ether solvents are preferable.

  A method for applying the coating solution is not particularly limited, and examples thereof include a dip coating method, a spray coating method, a beat coating method, a nozzle coating method, a spinner coating method, and a ring coating method.

  The thickness of the charge generation layer 12a is usually 0.01 to 5 μm, preferably 0.1 to 2 μm.

  The charge transport layer 12b includes a charge transport material and a binder resin.

  Examples of charge transport materials include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4, 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-trinitro Electron transport materials such as dibenzothiophene-5,5-dioxide and benzoquinone derivatives; poly (N-vinylcarbazole) and its derivatives, poly (γ-carbazolylethyl glutamate) and its derivatives, pyrene-formaldehyde condensates and their Derivatives, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, Examples include hole transport materials such as divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, and enamine derivatives, and two or more kinds may be used in combination.

  The binder resin is not particularly limited, and examples thereof include polystyrene, polyester, polyarate, polycarbonate, polyvinyl butyral, polyvinyl formal, and polyvinyl toluene.

  The mass ratio of the charge transport material to the binder resin is usually 0.2 to 3, and preferably 0.4 to 1.5.

  The charge transport layer 12b can be formed by applying a coating solution in which a charge transport material and a binder resin are dissolved or dispersed in a solvent on the charge generation layer 12a and then drying the coating solution.

  Examples of the solvent include, but are not limited to, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, and acetone.

  The thickness of the charge transport layer 12b is usually 5 to 25 μm.

  FIG. 2 shows another example of the structure of the photoreceptor of the present invention. The photoconductor 10 ′ has the same configuration as that of the photoconductor 10 except that a single photosensitive layer 12 ′ is formed instead of the photoconductive layer 12 including the charge generation layer 12a and the charge transport layer 12b.

  The photosensitive layer 12 ′ includes a charge generation material, a charge transport material, and a binder resin.

  The charge generation material and the charge transport material are the same as described above.

  As the binder resin, the binder resin used for the charge transport layer 12b can be used together with the binder resin used for the charge generation layer 12a as necessary.

  The mass ratio of the charge generating material to the binder resin is usually 0.05 to 0.40.

  The mass ratio of the charge transport material to the binder resin is usually 0.5 to 1.5.

  The photosensitive layer 12 ′ can be formed by applying a coating solution in which a charge generating substance, a charge transporting substance, and a binder resin are dissolved or dispersed in a solvent on the conductive support 11 and then drying.

  Although it does not specifically limit as a solvent, Tetrahydrofuran, a dioxane, a dichloroethane, a cyclohexane etc. are mentioned.

  A method for applying the coating solution is not particularly limited, and examples thereof include a dip coating method, a spray coating method, and a bead coating method.

  The thickness of the photosensitive layer 12 ′ is usually 5 to 25 μm.

  FIG. 3 shows another example of the structure of the photoreceptor of the present invention. The photoconductor 20 has the same configuration as the photoconductor 10 except that an undercoat layer 21 is formed between the conductive support 11 and the charge generation layer 12a.

  The undercoat layer 21 includes a resin.

  The resin is not particularly limited as long as it has excellent resistance to the solvent used in forming the charge generation layer 12a, but water-soluble resins such as polyvinyl alcohol, casein, sodium polyacrylate, copolymer nylon, methoxymethyl Examples include alcohol-soluble resins such as fluorinated nylon, resins in which a crosslinkable resin such as polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy resin is crosslinked.

  The undercoat layer 21 may further include metal oxide particles. Thereby, generation | occurrence | production of a moire and a raise of a residual potential can be suppressed.

  Although it does not specifically limit as a metal oxide particle, A titanium oxide particle, a silica particle, an alumina particle, a zirconium oxide particle, a tin oxide particle, an indium oxide particle etc. are mentioned.

  The undercoat layer 21 can also be formed using a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like.

  In addition, an alumina layer can be formed as the undercoat layer 21 by anodizing.

  Furthermore, an organic compound layer such as polyparaxylylene (parylene); an inorganic compound layer such as silica, tin dioxide, titanium oxide, ITO, and cerium oxide is formed as the undercoat layer 21 using a vacuum thin film forming method. You can also.

  The thickness of the undercoat layer 21 is usually 0.1 to 50 μm, preferably 1 to 5 μm.

  The coating solution for each layer may contain an antioxidant, an ultraviolet absorber, a radical scavenger, a softener, a dispersion stabilizer, an anti-settling agent, an anti-coloring agent, a leveling agent, an antifoaming agent, and a thickener as necessary. An agent, a matting agent, and the like may be further included.

  The antioxidant is not particularly limited, and examples thereof include hindered phenol antioxidants, amine antioxidants, sulfur antioxidants, and benzotriazole ultraviolet absorbers.

  FIG. 4 shows an example of the image forming apparatus of the present invention. The image forming apparatus 30 includes a photoconductor 10, a corona charger 31, an exposure device (not shown) that irradiates the photoconductor 10 with light L, a developing device 32, a pre-transfer corona charger 33, and a registration roller that conveys the recording paper P. 34, a transfer unit 35, a cleaning unit 36, and a static elimination lamp 37. At this time, the transfer device 35 includes a transfer corona charger 35a, a separation corona charger 35b, and a separation claw 35c, and the cleaning device 36 includes a pre-cleaning corona charger 36a, a cleaning brush 36b, and a cleaning blade 36c. .

  The photoconductor 10 has a drum shape, but may have a sheet shape or an endless belt shape.

  Corona charger 31, pre-transfer corona charger 33, transfer corona charger 35a, separation corona charger 35b, and pre-cleaning corona charger 36a include corotron, scorotron, solid state charger (solid state charger), etc. Is mentioned.

  The light source and the charge removal lamp 37 of the exposure device are not particularly limited, but a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), an electroluminescence (EL), or the like is used. be able to. At this time, a filter such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, or a color temperature conversion filter may be used to irradiate only light in a desired wavelength range.

  Instead of the pre-transfer corona charger 33, the transfer corona charger 35a, the separation corona charger 35b, or the pre-cleaning corona charger 36a, a light source may be installed.

  Although it does not specifically limit as the cleaning brush 37b, A fur brush etc. can be used.

  Next, a method for forming an image using the image forming apparatus 30 will be described. First, the surface of the photoconductor 10 is positively (negatively) charged using the corona charger 31 and then irradiated with the light L using the exposure device. A (negative) electrostatic latent image is formed. Next, when the electrostatic latent image formed on the surface of the photoreceptor 10 is developed with toner using the developing device 32, a toner image is formed. At this time, when developing with negative (positive) toner, a positive image is formed, and when developing with positive (negative) toner, a negative image is formed. Further, the toner image formed on the surface of the photoreceptor 10 is transferred onto the recording paper P conveyed by the registration roller 34 using the transfer device 35. Next, after cleaning the toner remaining on the surface of the photoconductor 10 to which the toner image has been transferred using the cleaning device 36, the surface of the photoconductor 10 is discharged using the charge eliminating lamp 37.

  FIG. 5 shows another example of the image forming apparatus of the present invention. The image forming apparatus 40 is a tandem image forming apparatus, and includes image forming units 30 ′ for each color of yellow, magenta, cyan, and black. The image forming unit 30 ′ is provided with a charging roller 31 ′ and a primary transfer roller 35 ′ in place of the corona charger 31 and the transfer device 35, respectively, and the pre-transfer corona charger 33 and the registration roller 34 are omitted. The image forming apparatus 30 has the same configuration except that the intermediate transfer belt 41 is installed.

  Next, a method for forming an image using the image forming apparatus 40 will be described. First, using each color image forming unit 30 ′, each color toner image is transferred to the intermediate transfer belt 41 and superimposed, thereby forming a full color toner image. Next, using the secondary transfer roller 42, the full color toner image formed on the surface of the intermediate transfer belt 41 is transferred to the recording paper P conveyed by the registration roller 43 and the transfer belt 44. Further, after the recording paper P on which the full color toner image has been transferred is conveyed using the transfer belt 44 and the conveyance belt 45, the full color toner image is fixed on the recording paper P using the fixing device 46. On the other hand, using the fur brush 47, the toner remaining on the surface of the intermediate transfer belt 41 to which the full color toner image has been transferred is cleaned.

  The process cartridge of the present invention is not particularly limited as long as it has the photoreceptor of the present invention and can be attached to and detached from the main body of an image forming apparatus such as a copying machine or a printer.

  The process cartridge of the present invention further includes one or more means selected from the group consisting of charging means, exposure means, developing means, transfer means, cleaning means, and static elimination means.

  FIG. 6 shows an example of the process cartridge of the present invention. The process cartridge 50 includes a photoreceptor 10, a corona charger 31, a developing device 32, a transfer roller 35 ′, and a cleaning device 36, and is detachable from the main body of the image forming apparatus.

  The photoreceptor of the present invention can be applied to electrophotographic application fields such as electrophotographic copying machines, laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited by an Example. In addition, a part means a mass part.

(Preparation of coating solution for undercoat layer)
3 parts of alkyd resin Beccosol 1307-60-EL (manufactured by DIC), 2 parts of melamine resin Super Becamine G-821-60 (manufactured by DIC), 20 parts of CR-EL of titanium oxide (manufactured by Ishihara Sangyo Co., Ltd.) And 100 parts of methyl ethyl ketone was mixed to obtain an undercoat layer coating solution.

(Preparation of coating solution for charge generation layer)
Chemical formula

で表されるビスアゾ顔料５部、ポリビニルブチラールのＸＹＨＬ（ＵＣＣ社製）１部、２−ブタノン１００部及びシクロヘキサノン２００部を混合して、電荷発生層用塗布液を得た。

5 parts of a bisazo pigment represented by the formula, 1 part of polyvinyl butyral XYHL (UCC), 100 parts of 2-butanone and 200 parts of cyclohexanone were mixed to obtain a coating solution for a charge generation layer.

(Preparation of coating solution for charge transport layer)
Bisphenol Z-type polycarbonate (A) 1 part, chemical formula

で表される電荷輸送物質（Ａ）１部及びテトラヒドロフラン１０部を混合して、電荷輸送層用塗布液を得た。

1 part of charge transport material (A) represented by the following and 10 parts of tetrahydrofuran were mixed to obtain a coating liquid for charge transport layer.

Example 1
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 0.66 parts of spherical titanium oxide particles PT401M (Ishihara Sangyo Co., Ltd.) with an aspect ratio of 1.2, acicular oxidation with an aspect ratio of 13 0.22 parts of titanium particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) and 340 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2 were mixed to obtain a coating solution for a protective layer of 5% by mass.

  An undercoat layer coating solution is applied on an aluminum conductive support having an outer diameter of 40 mm and a length of 340 mm using a dip coating method, and then dried by heating to a thickness of 3.5 μm. An undercoat layer was formed.

  On the conductive support on which the undercoat layer was formed, a charge generation layer coating solution was applied using a dip coating method, followed by drying by heating to form a charge generation layer having a thickness of 0.2 μm. .

  On the conductive support on which the charge generation layer was formed, a charge transport layer coating solution was applied using a dip coating method and then dried by heating to form a charge transport layer having a thickness of 20 μm.

  After applying the coating solution for the protective layer on the conductive support on which the charge transport layer is formed, using a spray coating method, it is dried at 130 ° C. for 20 minutes to form a protective layer having a thickness of 5.0 μm. As a result, a photoreceptor was obtained.

(Example 2)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 2.25 parts of spherical titanium oxide particles PT401M (Ishihara Sangyo Co., Ltd.) with an aspect ratio of 1.2, acicular oxidation with an aspect ratio of 13 0.75 parts of titanium particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) and 380 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2 were mixed to obtain a 5% by mass protective layer coating solution.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Example 3)
7 parts of charge transport material (A), 10 parts of bisphenol Z type polycarbonate (A), 4.25 parts of spherical titanium oxide particles PT401M (Ishihara Sangyo Co., Ltd.) with an aspect ratio of 1.2, acicular oxidation with an aspect ratio of 13 1.42 parts of titanium particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) and 431 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2 were mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

Example 4
7 parts of charge transport material (A), 10 parts of bisphenol Z type polycarbonate (A), 8.50 parts of spherical titanium oxide particles PT401M (Ishihara Sangyo Co., Ltd.) with an aspect ratio of 1.2, acicular oxidation with an aspect ratio of 13 2.83 parts of titanium particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) and 538 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2 were mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Example 5)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 4.53 parts of spherical titanium oxide particles PT401M (Ishihara Sangyo Co., Ltd.) with an aspect ratio of 1.2, acicular oxidation with an aspect ratio of 13 1.13 parts of titanium particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) and 431 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2 were mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Example 6)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 4.72 parts of spherical titanium oxide particles PT401M (Ishihara Sangyo Co., Ltd.) with an aspect ratio of 1.2, acicular oxidation with an aspect ratio of 13 0.94 parts of titanium particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) and 431 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2 were mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Example 7)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 3.78 parts of spherical titanium oxide particles PT401M (Ishihara Sangyo Co., Ltd.) with an aspect ratio of 1.2, acicular oxidation with an aspect ratio of 13 1.89 parts of titanium particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) and 431 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2 were mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Example 8)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 4.25 parts of spherical silicon oxide particles KMPX100 (manufactured by Shin-Etsu Chemical Co., Ltd.) with an aspect ratio of 1.2, needle-like with an aspect ratio of 13 1.42 parts of titanium oxide particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) and 431 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2 were mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

Example 9
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 4.25 parts of spherical silicon oxide particles KMPX100 (manufactured by Shin-Etsu Chemical Co., Ltd.) having an aspect ratio of 1.2, and an aspect ratio of 20 to 100 By mixing 1.42 parts of nano-serum fibers (made by Argonide) of acicular aluminum oxide particles and 431 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2, a coating solution for protective layer of 5% by mass is obtained. It was.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Example 10)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 4.25 parts of spherical titanium oxide particles PT401M (Ishihara Sangyo Co., Ltd.) with an aspect ratio of 1.2, needles with an aspect ratio of 20 to 100 Of aluminum oxide particles nanoserum fiber (manufactured by Argonide) 1.42 parts mixed solvent 431 parts by mass ratio of tetrahydrofuran and cyclohexanone 7: 2 to obtain a coating solution for protective layer of 5% by mass .

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Example 11)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 4.25 parts of spherical aluminum oxide particles AA03 (manufactured by Sumitomo Chemical Co., Ltd.) with an aspect ratio of 1.1, acicular oxidation with an aspect ratio of 13 1.42 parts of titanium particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) and 431 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2 were mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Example 12)
7 parts of charge transport material (A), 10 parts of bisphenol Z type polycarbonate (A), 4.25 parts of spherical aluminum oxide particles AA05 (manufactured by Sumitomo Chemical Co., Ltd.) with an aspect ratio of 1.1, acicular oxidation with an aspect ratio of 13 1.42 parts of titanium particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) and 431 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2 were mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Example 13)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 4.25 parts of spherical aluminum oxide particles AA03 (Sumitomo Chemical Co., Ltd.) having an aspect ratio of 1.1, needles having an aspect ratio of 20 to 100 Of aluminum oxide particles nanoserum fiber (manufactured by Argonide) 1.42 parts mixed solvent 431 parts by mass ratio of tetrahydrofuran and cyclohexanone 7: 2 to obtain a coating solution for protective layer of 5% by mass .

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Example 14)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 4.25 parts of spherical aluminum oxide particles AA05 (Sumitomo Chemical Co., Ltd.) having an aspect ratio of 1.1, needles having an aspect ratio of 20 to 100 Of aluminum oxide particles nanoserum fiber (manufactured by Argonide) 1.42 parts mixed solvent 431 parts by mass ratio of tetrahydrofuran and cyclohexanone 7: 2 to obtain a coating solution for protective layer of 5% by mass .

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Comparative Example 1)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 5.67 parts of spherical titanium oxide particles PT401M (Ishihara Sangyo Co., Ltd.) having an aspect ratio of 1.2, and a mass ratio of tetrahydrofuran and cyclohexanone of 7 : 431 parts of a mixed solvent of 2 was mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Comparative Example 2)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 11.33 parts of spherical titanium oxide particles PT401M (Ishihara Sangyo Co., Ltd.) with an aspect ratio of 1.2, and a mass ratio of tetrahydrofuran and cyclohexanone of 7 : 5 parts of a mixed solvent of 538 was mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Comparative Example 3)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 5.67 parts of acicular titanium oxide particles FTL-100 (produced by Ishihara Sangyo Co., Ltd.) with an aspect ratio of 13, mass ratio of tetrahydrofuran and cyclohexanone 431 parts of a 7: 2 mixed solvent was mixed to obtain a 5% by mass protective layer coating solution.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Comparative Example 4)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 11.33 parts of acicular titanium oxide particles FTL-100 (produced by Ishihara Sangyo Co., Ltd.) with an aspect ratio of 13, mass ratio of tetrahydrofuran and cyclohexanone 538 parts of a 7: 2 mixed solvent was mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Comparative Example 5)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 0.57 parts of spherical titanium oxide particles PT401M (Ishihara Sangyo Co., Ltd.) with an aspect ratio of 1.2, acicular oxidation with an aspect ratio of 13 0.19 parts of titanium particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) and 337 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2 were mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Comparative Example 6)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 10.43 parts of spherical titanium oxide particles PT401M (Ishihara Sangyo Co., Ltd.) with an aspect ratio of 1.2, acicular oxidation with an aspect ratio of 13 3.47 parts of titanium particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) and 587 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2 were mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Comparative Example 7)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 4.86 parts of spherical titanium oxide particles PT401M (Ishihara Sangyo Co., Ltd.) with an aspect ratio of 1.2, acicular oxidation with an aspect ratio of 13 0.81 part of titanium particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) and 431 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2 were mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Comparative Example 8)
7 parts of charge transport material (A), 10 parts of bisphenol Z-type polycarbonate (A), 2.83 parts of spherical titanium oxide particles PT401M (Ishihara Sangyo Co., Ltd.) with an aspect ratio of 1.2, acicular oxidation with an aspect ratio of 13 2.83 parts of titanium particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) and 431 parts of a mixed solvent having a mass ratio of tetrahydrofuran and cyclohexanone of 7: 2 were mixed to obtain a coating solution for a protective layer of 5% by mass.

  A photoconductor was obtained in the same manner as in Example 1 except that the obtained protective layer coating solution was used.

(Example 15)
10 parts KAYARAD TMPTA (manufactured by Nippon Kayaku Co., Ltd.) as a compound having no charge transporting structure and having 3 or more radical polymerizable groups, a compound having a charge transporting structure and one radical polymerizable group As the chemical formula

で表される化合物（Ａ）１０部、光重合開始剤のイルガキュア１８４（チバ・スペシャルティ・ケミカルズ製）１部、アスペクト比が１．１の球状酸化アルミニウム粒子ＡＡ０３（住友化学社製）５．２５部、アスペクト比が１３の針状酸化チタン粒子ＦＴＬ−１００（石原産業社製）１．７５部及びテトラヒドロフラン１５９部を混合して、１５質量％の保護層用塗布液を得た。

10 parts of the compound (A) represented by the formula, 1 part of Irgacure 184 (manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator, 5.25 spherical aluminum oxide particles AA03 (manufactured by Sumitomo Chemical Co., Ltd.) having an aspect ratio of 1.1. Part, 1.75 parts of acicular titanium oxide particles FTL-100 (Ishihara Sangyo Co., Ltd.) having an aspect ratio of 13 and 159 parts of tetrahydrofuran were mixed to obtain a coating solution for a protective layer of 15% by mass.

  An undercoat layer coating solution is applied on an aluminum conductive support having an outer diameter of 40 mm and a length of 340 mm using a dip coating method, and then dried by heating to a thickness of 3.5 μm. An undercoat layer was formed.

  On the conductive support on which the undercoat layer was formed, a charge generation layer coating solution was applied using a dip coating method, followed by drying by heating to form a charge generation layer having a thickness of 0.2 μm. .

  On the conductive support on which the charge generation layer was formed, a charge transport layer coating solution was applied using a dip coating method and then dried by heating to form a charge transport layer having a thickness of 20 μm.

The coating liquid for protective layers was apply | coated on the electroconductive support body in which the charge transport layer was formed using the spray coat method. Next, using a metal halide lamp, after irradiation with light having a wavelength of 365 nm under the conditions of irradiation intensity of 700 mW / cm ² and irradiation time of 4 minutes, the film was dried at 130 ° C. for 30 minutes, and the thickness was 5.0 μm. A protective layer was formed to obtain a photoreceptor.

(Example 16)
KAYARAD TMPTA (manufactured by Nippon Kayaku Co., Ltd.) 10 parts, compound (A) 10 parts, photopolymerization initiator Irgacure 184 (manufactured by Ciba Specialty Chemicals), spherical aluminum oxide particles AA05 having an aspect ratio of 1.1 Sumitomo Chemical Co., Ltd.) 5.25 parts, 1.75 parts of acicular titanium oxide particles FTL-100 (manufactured by Ishihara Sangyo Co., Ltd.) with an aspect ratio of 13 and 159 parts of tetrahydrofuran are mixed, and a 15% by mass protective layer coating is applied. A liquid was obtained.

  A photoconductor was obtained in the same manner as in Example 15 except that the obtained protective layer coating solution was used.

(Example 17)
KAYARAD TMPTA (Nippon Kayaku Co., Ltd.) 10 parts, Compound (A) 10 parts, Photopolymerization initiator Irgacure 184 (Ciba Specialty Chemicals) 1 part, spherical aluminum oxide particles AA03 (aspect ratio 1.1) Sumitomo Chemical Co., Ltd.) 5.25 parts, 1.75 parts of needle-shaped aluminum oxide particle nanoserum fibers (made by Argonide) having an aspect ratio of 20 to 100, and 159 parts of tetrahydrofuran were mixed to form a 15% by mass protective layer. A coating solution was obtained.

  A photoconductor was obtained in the same manner as in Example 15 except that the obtained protective layer coating solution was used.

(Example 18)
KAYARAD TMPTA (manufactured by Nippon Kayaku Co., Ltd.) 10 parts, compound (A) 10 parts, photopolymerization initiator Irgacure 184 (manufactured by Ciba Specialty Chemicals), spherical aluminum oxide particles AA05 having an aspect ratio of 1.1 Sumitomo Chemical Co., Ltd.) 5.25 parts, 1.75 parts of needle-shaped aluminum oxide particle nanoserum fibers (made by Argonide) having an aspect ratio of 20 to 100, and 159 parts of tetrahydrofuran were mixed to form a 15% by mass protective layer. A coating solution was obtained.

  A photoconductor was obtained in the same manner as in Example 15 except that the obtained protective layer coating solution was used.

(Comparative Example 9)
KAYARAD TMPTA (Nippon Kayaku Co., Ltd.) 10 parts, Compound (A) 10 parts, Photopolymerization initiator Irgacure 184 (Ciba Specialty Chemicals) 1 part, spherical aluminum oxide particles AA03 (aspect ratio 1.1) 7.00 parts (manufactured by Sumitomo Chemical Co., Ltd.) and 159 parts of tetrahydrofuran were mixed to obtain a coating solution for a protective layer of 15% by mass.

  A photoconductor was obtained in the same manner as in Example 15 except that the obtained protective layer coating solution was used.

(Comparative Example 10)
KAYARAD TMPTA (Nippon Kayaku Co., Ltd.) 10 parts, Compound (A) 10 parts, Photopolymerization initiator Irgacure 184 (Ciba Specialty Chemicals) 1 part, Acicular aluminum oxide particles having an aspect ratio of 20 to 100 Nanoserum fiber (manufactured by Argonide) 7.00 parts and 159 parts of tetrahydrofuran were mixed to obtain a coating solution for a protective layer of 15% by mass.

  A photoconductor was obtained in the same manner as in Example 15 except that the obtained protective layer coating solution was used.

(Comparative Example 11)
A photoconductor was obtained in the same manner as in Example 1 except that the protective layer was not formed.

  In Table 1, the structure of the protective layer of Examples 1-18 and Comparative Examples 1-10 is shown.

（実機通紙試験）
ｉＰＳｉＯ ＳＰ Ｃ８１１（リコー社製）を用いて、用紙Ｍｙ Ｐａｐｅｒ Ａ４（ＮＢＳリコー社製）に、画像面積率が１０％のブラックの格子画像を２０万枚形成し、感光体の耐摩耗性、耐傷性、微細ドットの再現性及び残留電位を評価した。

(Real machine paper test)
Using iPSiO SP C811 (manufactured by Ricoh), 200,000 black lattice images with an image area ratio of 10% were formed on a paper My Paper A4 (manufactured by NBS Ricoh), and the abrasion resistance and scratch resistance of the photoconductor , Reproducibility of fine dots and residual potential were evaluated.

(Abrasion resistance)
Using a Fisherscope eddy current film thickness meter MMS, the thickness of 20 points on the photosensitive member before and after the actual paper passing test was measured, the wear amount was calculated, and the wear resistance was evaluated.

  Table 2 shows the evaluation results of the wear amount.

なお、比較例１１の感光体は、摩耗量が多かったため、５万枚で実機通紙試験を終了した。

Since the photoconductor of Comparative Example 11 had a large amount of wear, the actual machine passing test was completed with 50,000 sheets.

(Scratch resistance)
The scratches on the surface of the photoreceptor after the actual machine paper feeding test were visually observed to evaluate the scratch resistance. In addition, the case where a flaw was not confirmed was evaluated as ◯, the case where a flaw was confirmed slightly as Δ, and the case where a flaw was confirmed as x.

  Table 3 shows the evaluation results of scratch resistance.

（微細ドットの再現性）
実機通紙試験後に、日本画像学会発行テストチャートＮＯ．３を用いて、画像を形成し、目視及び光学顕微鏡で観察し、微小ドットの再現性を評価した。なお、細線の再現性が良好である場合を○、細線がやや太る場合を△、細線が太る場合を×として、判定した。

(Reproducibility of fine dots)
After the actual machine paper passing test, test chart NO. 3 was used to form an image and observed visually and with an optical microscope to evaluate the reproducibility of the fine dots. In addition, the case where the reproducibility of the fine line was good was judged as ◯, the case where the fine line was slightly thicker as Δ, and the case where the thin line was thick as x.

  Table 4 shows the evaluation results of the reproducibility of the minute dots.

（残留電位）
実機通紙試験前後に、露光エネルギー０．５μＪ／ｃｍ^２で露光した露光部の電位を、表面電位計Ｍｏｄｅｌ３４４（Ｔｒｅｋ社製）を用いて測定し、残留電位を評価した。

(Residual potential)
Before and after the actual machine passing test, the potential of the exposed portion exposed with an exposure energy of 0.5 μJ / cm ² was measured using a surface potential meter Model 344 (manufactured by Trek) to evaluate the residual potential.

  Table 5 shows the evaluation results of the potential of the exposed area.

表２〜５より、実施例１〜１８の感光体は、耐摩耗性、耐傷性及び微細ドットの再現性に優れ、残留電位の上昇を抑制できることがわかる。

From Tables 2 to 5, it can be seen that the photoconductors of Examples 1 to 18 are excellent in abrasion resistance, scratch resistance and reproducibility of fine dots, and can suppress an increase in residual potential.

  On the other hand, the photoconductors of Comparative Examples 1, 2, and 9 have poor scratch resistance because the protective layer does not contain acicular particles. In the photoconductor of Comparative Example 2, since the content of spherical particles in the protective layer is 40% by mass, the residual potential increases.

  In the photoconductors of Comparative Examples 3, 4, and 10, since the protective layer does not contain spherical particles, wear resistance and scratch resistance are reduced. In the photoconductor of Comparative Example 4, since the content of acicular particles in the protective layer is 40% by mass, the reproducibility of fine dots is lowered and the residual potential is increased.

  In the photoconductor of Comparative Example 5, since the total content of spherical particles and acicular particles in the protective layer is 4% by mass, the wear resistance and scratch resistance are lowered.

The photoconductor of Comparative Example 6 has a total content of spherical particles and needle-like particles in the protective layer of 45% by mass, so that the residual potential increases and the reproducibility of fine dots decreases. Since the mass ratio of spherical particles to acicular particles is 6, the scratch resistance is reduced.

  In the photoconductor of Comparative Example 8, since the mass ratio of spherical particles to acicular particles is 1, the wear resistance, scratch resistance, and reproducibility of fine dots are reduced.

  Since the photoconductor of Comparative Example 11 does not have a protective layer, wear resistance and scratch resistance are reduced.

10, 10 'photoreceptor 11 conductive support 12, 12' photosensitive layer 12a charge generation layer 12b charge transport layer 13 protective layer 30, 40 image forming apparatus 31 corona charger 31 'charging roller 32 developer 35 transfer device 35' Primary transfer roller 41 Intermediate transfer belt 42 Secondary transfer roller 50 Process cartridge

JP 2005-99688 A JP 2008-146022 A

Claims (10)

A photosensitive layer and a protective layer are sequentially laminated on the conductive support,
The protective layer includes a binder resin, spherical particles, and acicular particles, and the total content of the spherical particles and the acicular particles is 5% by mass or more and 40% by mass or less,
A photoreceptor having a mass ratio of the spherical particles to the acicular particles of 2 or more and 5 or less.   The photoreceptor according to claim 1, wherein the binder resin includes a crosslinked resin.   The binder resin is a resin in which a compound having no charge transporting structure and having three or more radical polymerizable groups and a compound having a charge transporting structure and having one radical polymerizable group are crosslinked. The photoreceptor according to claim 2, further comprising:   4. The photoreceptor according to claim 1, wherein the spherical particles are spherical inorganic particles.   The photoreceptor according to claim 4, wherein the spherical inorganic particles are spherical metal oxide particles.   6. The photoreceptor according to claim 5, wherein the spherical particles are spherical aluminum oxide particles.   The photoconductor according to claim 1, wherein the acicular particles are acicular inorganic particles.   The photoreceptor according to claim 7, wherein the acicular inorganic particles are acicular metal oxide particles. A photoconductor according to any one of claims 1 to 8,
Charging means for charging the photoreceptor;
Exposure means for exposing the charged photoreceptor to form an electrostatic latent image;
Developing means for developing the electrostatic latent image formed on the photoreceptor with toner to form a toner image;
An image forming apparatus comprising transfer means for transferring a toner image formed on the photoreceptor to a recording medium. A photoconductor according to any one of claims 1 to 8,
A process cartridge which is detachable from a main body of an image forming apparatus.

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