JP2012203253A - Electrophotographic photoreceptor, image forming apparatus, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the accumulation of residual potential even after repeated static charging and elimination.SOLUTION: An electrophotographic photoreceptor includes a conductive substrate 1, and a photosensitive layer 2 on the conductive substrate 1. The surface layer of the photosensitive layer 2 (protective layer 2C) contains: at least one compound selected from a guanamine compound and a melamine compound; a cross-linked product of a charge transport material having at least one substituent group selected from -OH, -OCH, -HN, -SH, and -COOH; an oligomer containing fluororesin particles and fluorine atoms; and at least one solvent selected from a lower alcohol solvent having 6 or less carbon atoms, a keton-based solvent, an ether-based solvent, an ester-based solvent, and a hydrocarbon-based solvent. The content ratio of the charge transport material in the surface layer (protection layer 2C) is 85% or more.

Description

  The present invention relates to an electrophotographic photosensitive member, an image forming apparatus, and a process cartridge.

  A technology in which fluororesin particles such as polytetrafluoroethylene are dispersed in the surface layer of a photoconductor used in an electrophotographic image forming apparatus, and the technology in which the fluororesin particles are dispersed in the surface layer of the photoconductor For example, a method using an oligomer containing a fluorine atom as a dispersion aid is disclosed (for example, see Patent Document 1).

Also disclosed is an electrophotographic photosensitive member in which the surface layer of the photosensitive layer is formed using a coating solution containing a monomer in a solvent, and the amount of residual solvent in the surface layer at the start of polymerization is 5000 ppm or less. (For example, refer to Patent Document 2).
Further, in the method for producing an electrophotographic photosensitive member having a conductive support and a charge generation layer, a charge transport layer and a surface layer on the conductive support, the charge generation layer comprises a charge transport material, a resin and a solvent. A step of applying a coating solution and drying at 100 ° C. or less to form the charge transport layer; a coating solution comprising a hole transport compound and a solvent is applied on the charge transport layer; and an electron having an acceleration voltage of 100 kV or less A step of forming the surface layer by heating and curing at 140 ° C. or lower after irradiation with a wire, and the amount of residual solvent in the charge transport layer after formation of the charge transport layer and before formation of the surface layer is 0 An electrophotographic photosensitive member of 5 mass% to 5 mass% is disclosed (for example, see Patent Document 3).

JP 2008-46197 A JP 2007-241158 A JP 2009-251507 A

  The object of the present invention is to provide a lower alcohol solvent having 6 or less carbon atoms, and at least one solvent selected from ketone solvents, ether solvents, ester solvents and hydrocarbon solvents. This is to suppress the accumulation of the residual potential even if the charge removal is repeated.

The above problem is solved by the following means. That is,
The invention according to claim 1
A conductive substrate, and a photosensitive layer on the conductive substrate;
The layer constituting the outermost surface of the photosensitive layer is at least one selected from guanamine compounds and melamine compounds, and at least one selected from —OH, —OCH ₃ , —NH ₂ , —SH and —COOH. Cross-linked product of charge transporting material having one substituent, fluorine resin particles, oligomer containing fluorine atom, lower alcohol solvent having 6 or less carbon atoms, ketone solvent, ether solvent, ester solvent and carbonization And at least one solvent selected from hydrogen-based solvents,
In the electrophotographic photosensitive member, the content of the charge transporting material in the layer constituting the outermost surface is 85% by mass or more.

The invention according to claim 2
The lower alcohol solvent having 6 or less carbon atoms is at least one selected from cyclopentanol, methanol, ethanol, i-propanol, 2-butanol, and n-pentanol;
At least one solvent selected from the ketone solvents, ether solvents, ester solvents and hydrocarbon solvents is cyclopentanone, butyl acetate, isobutyl acetate, methyl ethyl ketone, methyl isobutyl ketone, toluene, ethylbenzene, tetrahydrofuran, The electrophotographic photosensitive member according to claim 1, which is at least one selected from 2-methyltetrahydrofuran and 2-methyltetrahydrofuran.

The invention according to claim 3
An electrophotographic photoreceptor according to claim 1;
A charging device for charging the surface of the electrophotographic photosensitive member;
An electrostatic latent image forming apparatus for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member;
A developing device for developing the electrostatic latent image with a developer to form a toner image;
A transfer device for transferring the toner image to a transfer medium;
An image forming apparatus.

The invention according to claim 4
A process cartridge comprising at least the electrophotographic photosensitive member according to claim 1 and detachable from an image forming apparatus.

  According to the invention of claim 1, when it does not contain a lower alcohol solvent having 6 or less carbon atoms and at least one solvent selected from a ketone solvent, an ether solvent, an ester solvent and a hydrocarbon solvent In contrast, the accumulation of residual potential is suppressed even when charging and discharging are repeated.

  According to the invention of claim 2, the lower alcohol solvent having 6 or less carbon atoms is not at least one selected from cyclopentanol, methanol, ethanol, i-propanol, 2-butanol, and n-pentanol. And / or at least one solvent selected from the ketone solvents, ether solvents, ester solvents and hydrocarbon solvents is cyclopentanone, butyl acetate, isobutyl acetate, methyl ethyl ketone, methyl isobutyl ketone, toluene As compared with the case where at least one selected from ethylbenzene, tetrahydrofuran, and 2-methyltetrahydrofuran is not used, accumulation of residual potential is suppressed even when charging and discharging are repeated.

  According to the invention of claim 3, the photosensitive agent does not contain a lower alcohol solvent having 6 or less carbon atoms and at least one solvent selected from a ketone solvent, an ether solvent, an ester solvent and a hydrocarbon solvent. Compared to the case of having a body, an image having excellent repeated image quality is formed.

  According to the invention of claim 4, a photosensitivity containing no lower alcohol solvent having 6 or less carbon atoms and at least one solvent selected from ketone solvents, ether solvents, ester solvents and hydrocarbon solvents. Compared to the case of having a body, an image having excellent repeated image quality is formed.

1 is a schematic partial cross-sectional view showing an electrophotographic photosensitive member of a first aspect used in the present embodiment. It is a general | schematic fragmentary sectional view which shows the electrophotographic photoreceptor of the 2nd aspect used for this embodiment. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows the other image forming apparatus which concerns on this embodiment.

  Hereinafter, embodiments of the present invention will be described in detail.

<Electrophotographic photoreceptor>
The electrophotographic photoreceptor according to the exemplary embodiment (hereinafter referred to as “photoreceptor”) includes a conductive substrate and a layer that forms a outermost surface of the photosensitive layer, and includes a photosensitive layer on the conductive substrate ( (Hereinafter referred to as “surface layer”) contains the following components (a) to (e), and the content of the following charge transport material in the surface layer is 85% by mass or more.
(A) at least one (a-1) selected from a guanamine compound and a melamine compound and at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH and —COOH (hereinafter “ Charge transport material (a-2) having a specific substituent ”) and a cross-linked product (b) fluororesin particles (c) an oligomer containing a fluorine atom (hereinafter referred to as“ specific oligomer ”)
(D) Lower alcohol solvent having 6 or less carbon atoms (hereinafter referred to as “lower alcohol solvent”)
(E) At least one solvent selected from ketone solvents, ether solvents, ester solvents and hydrocarbon solvents (hereinafter referred to as “other specific solvents”)

  In a photoreceptor having a surface layer containing (b) a fluororesin particle and (b) a specific oligomer that serves to disperse the (b) fluororesin particle by adsorbing to the fluororesin particle, When static electricity removal is repeated, residual potential may accumulate. Although this mechanism is not clear, when (c) the specific oligomer is present in the surface layer in the state of being adsorbed to (b) the fluororesin particles, it does not become a polarization component, while (c) the specific oligomer is (b ) When present alone without adsorbing to the fluororesin particles, it acts as a polarization component and is considered to be a substance that accumulates electric charges.

Here, (d) a lower alcohol solvent having 6 or less carbon atoms has a property that (c) the specific oligomer is hardly dissolved. In this embodiment, (d) a lower alcohol solvent having 6 or less carbon atoms is contained in the surface layer, that is, (d) a lower alcohol solvent having 6 or less carbon atoms is used as a solvent when forming the surface layer. Thus, the compatibility between (c) the specific oligomer and the solvent is suppressed, and the affinity between (c) the specific oligomer and (b) the fluororesin particles is relatively increased. As a result, (c) the specific oligomer does not easily exist alone in the surface layer, and (b) adsorbs to the fluororesin particles, so that the (c) specific oligomer exists in the surface layer as a substance that accumulates charges. It is presumed that the accumulation of residual potential is suppressed even when charging and discharging are repeated in the photoconductor according to the present embodiment.
In addition, in a lower alcohol solvent having more than 6 carbon atoms, it is considered that (c) the compatibility between the specific oligomer and the solvent cannot be suppressed, and accumulation of residual potential when charging and discharging are repeated can be suppressed. Absent.

  Moreover, it is thought that (c) the dispersibility of specific oligomer itself improves by using (e) other specific solvents, and (b) the function which disperse | distributes a fluororesin particle is exhibited effectively. When the surface layer does not contain (e) other specific solvent, (b) the aggregate of the fluororesin particles remains in the surface layer because (b) the dispersion of the fluororesin particles is not good during the formation of the surface layer. It is presumed that the aggregate portion is not charged, and as a result, the formed image is inferior in granularity (circularity of each dot constituting the image).

In the present embodiment, (d) the lower alcohol solvent and (e) other specific solvent present in the surface layer of the photoreceptor are solvents used in the coating solution for forming the surface layer, It refers to what remains as a residual solvent without being completely evaporated even after the surface layer is dried and cured when the surface layer is formed.
Hereinafter, the configuration of the photoreceptor in the present embodiment will be described.

-Structure of photoconductor-
The photosensitive layer according to the present embodiment may have a function-integrated type photosensitive layer having both charge transporting ability and charge generating ability, or a function separation type photosensitive layer including a charge transporting layer and a charge generating layer. You may have. Furthermore, you may provide other layers, such as an undercoat layer and a protective layer.

Hereinafter, the configuration of the photoconductor in the present embodiment will be described with reference to FIGS. 1 and 2, but the present embodiment is not limited to FIGS. 1 and 2.
FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of the photoreceptor in this embodiment. In FIG. 1, 1 is a conductive substrate, 2 is a photosensitive layer, 2A is a charge generation layer, 2B is a charge transport layer, 2C represents a protective layer and 4 represents an undercoat layer.
The photoreceptor shown in FIG. 1 has a layer structure in which an undercoat layer 4, a charge generation layer 2A, a charge transport layer 2B, and a protective layer 2C are laminated on a conductive substrate 1 in this order. It is composed of three layers including a generation layer 2A, a charge transport layer 2B, and a protective layer 2C (the photoreceptor of the first embodiment).
In the photoreceptor shown in FIG. 1, the protective layer 2C is a surface layer constituting the outermost surface.

FIG. 2 is a schematic cross-sectional view showing another example of the layer structure of the photoreceptor in the present embodiment, and the reference numerals shown in FIG. 2 are synonymous with those shown in FIG.
The photoreceptor shown in FIG. 2 has a layer structure in which an undercoat layer 4, a charge generation layer 2A, and a charge transport layer 2B are laminated in this order on a conductive substrate 1, and the photosensitive layer 2 includes the charge generation layer 2A and the charge generation layer 2A. It is composed of two layers of the charge transport layer 2B (photoconductor of the second aspect).
In the photoreceptor shown in FIG. 2, the charge transport layer 2B is a surface layer constituting the outermost surface.

  In the embodiment shown in FIG. 1, the photosensitive layer 2 is composed of three layers including the charge generation layer 2A, the charge transport layer 2B and the protective layer 2C as described above. As an aspect having a charge transport layer 2B, a charge generation layer 2A, and a protective layer 2C in this order from the conductive substrate 1 side, an aspect having a function-integrated type photosensitive layer and a protective layer 2C having both charge transport ability and charge generation ability Etc.

  Hereinafter, each of the first to second aspects will be described as an example of the photoconductor in the present exemplary embodiment.

[Photoreceptor of First Aspect: Surface Layer = Protective Layer]
As shown in FIG. 1, the photoreceptor of the first embodiment has a layer structure in which an undercoat layer 4, a charge generation layer 2A, a charge transport layer 2B, and a protective layer 2C are laminated in this order on a conductive substrate 1. The protective layer 2C is a surface layer.

Conductive substrate As the conductive substrate 1, a conductive substrate having conductivity is used. For example, a metal or alloy such as aluminum, copper, zinc, stainless steel, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, or the like Paper, plastic coated, vapor-deposited, or laminated with metal plates, metal drums, and metal belts, or conductive polymers, conductive compounds such as indium oxide, and metals or alloys such as aluminum, palladium, and gold A film, a belt, etc. are mentioned. Here, “conductive” means that the volume resistivity is less than 10 ¹³ Ωcm.

  If the photoreceptor of the first aspect is used in a laser printer, the surface of the conductive substrate 1 is desirably roughened to a center line average roughness Ra of 0.04 μm or more and 0.5 μm or less. However, when non-interfering light is used as a light source, roughening is not particularly required.

  Surface roughening methods include wet honing by suspending an abrasive in water and spraying it on the support, or centerless grinding and anodization in which the support is brought into contact with a rotating grindstone and continuously ground. Processing is desirable.

  Further, as another roughening method, a conductive or semiconductive powder is dispersed in a resin without roughening the surface of the conductive substrate 1, and a layer is formed on the surface of the support. A method of roughening with particles dispersed in the layer is also desirably used.

  Here, the roughening treatment by anodic oxidation is to form an oxide film on the aluminum surface by anodizing in an electrolyte solution using aluminum as an anode. Examples of the electrolyte solution include a sulfuric acid solution and an oxalic acid solution. However, since the porous anodic oxide film formed by anodic oxidation is chemically active as it is, fine pores of the anodic oxide film may be added to pressurized water vapor or boiling water (metal salt such as nickel may be added). It is desirable to perform a sealing treatment to block the volume expansion due to the hydration reaction, and to change to a more stable hydrated oxide. The thickness of the anodic oxide film is desirably 0.3 μm or more and 15 μm or less.

Further, the conductive substrate 1 may be subjected to treatment with an acidic aqueous solution or boehmite treatment.
The treatment with an acidic treatment solution containing phosphoric acid, chromic acid and hydrofluoric acid is carried out as follows. First, an acidic treatment liquid is prepared. The mixing ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment liquid is such that phosphoric acid is in the range of 10% by mass to 11% by mass, chromic acid is in the range of 3% by mass to 5% by mass, and hydrofluoric acid is 0. The concentration of these acids is preferably in the range of 13.5 mass% to 18 mass%. The treatment temperature is desirably 42 ° C. or higher and 48 ° C. or lower. The film thickness is preferably from 0.3 μm to 15 μm.

  The boehmite treatment is performed by immersing in pure water of 90 ° C. or more and 100 ° C. or less for 5 minutes or more and 60 minutes or less, or by contacting with heated steam of 90 ° C. or more and 120 ° C. or less for 5 minutes or more and 60 minutes or less. The film thickness is preferably 0.1 μm or more and 5 μm or less. This is further anodized using an electrolyte solution with lower film solubility than other types such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, citrate, etc. It may be processed.

-Undercoat layer The undercoat layer 4 is comprised as a layer which contained the inorganic particle in binder resin, for example.
As the inorganic particles, those having a powder resistance (volume resistivity) of 10 ² Ω · cm to 10 ¹¹ Ω · cm are desirably used.

  Among these, inorganic particles (conductive metal oxide) such as tin oxide, titanium oxide, zinc oxide and zirconium oxide are preferably used as the inorganic particles having the above resistance value, and zinc oxide is particularly preferably used.

  In addition, the inorganic particles may be subjected to a surface treatment, or may be used as a mixture of two or more types such as those having different surface treatments or particles having different particle diameters. The volume average particle size of the inorganic particles is desirably in the range of 50 nm to 2000 nm (desirably 60 to 1000).

As the inorganic particles, those having a specific surface area of 10 m ² / g or more by the BET method are desirably used.

  Further, in addition to the inorganic particles, an acceptor compound may be contained. Any acceptor compound may be used. For example, quinone compounds such as chloranil and bromoanil, tetracyanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2,4,5,7- Fluorenone compounds such as tetranitro-9-fluorenone, 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole and 2,5-bis (4-naphthyl)- Oxadiazole compounds such as 1,3,4-oxadiazole, 2,5-bis (4-diethylaminophenyl) 1,3,4-oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, Electron transporting substances such as diphenoquinone compounds such as 5,5′tetra-t-butyldiphenoquinone are desirable, and in particular, anthraquinone structure Compounds is desired. Furthermore, acceptor compounds having an anthraquinone structure such as hydroxyanthraquinone compounds, aminoanthraquinone compounds, aminohydroxyanthraquinone compounds, and the like are desirably used, and specific examples include anthraquinone, alizarin, quinizarin, anthralfin, and purpurin.

  The content of these acceptor compounds may be arbitrarily set, but is desirably 0.01% by mass or more and 20% by mass or less with respect to the inorganic particles. Furthermore, 0.05 mass% or more and 10 mass% or less are desirable.

  The acceptor compound may be added only when the undercoat layer 4 is applied, or may be previously attached to the surface of the inorganic particles. Examples of the method for imparting the acceptor compound to the surface of the inorganic particles include a dry method or a wet method.

  When surface treatment is performed by a dry method, the inorganic particles are treated by dropping an acceptor compound dissolved in an organic solvent directly or with dry air or nitrogen gas while stirring with a mixer having a large shearing force. The The addition or spraying is preferably performed at a temperature below the boiling point of the solvent. After addition or spraying, baking may be performed at 100 ° C. or higher. About baking temperature and time, it implements in arbitrary ranges.

  As the wet method, the inorganic particles are stirred in a solvent, dispersed using ultrasonic waves, a sand mill, an attritor, a ball mill, or the like, and after adding or accepting an acceptor compound, the solvent is removed. The solvent removal method is distilled off by filtration or distillation. After removing the solvent, baking may be performed at 100 ° C. or higher. About baking temperature and time, it implements in arbitrary ranges. In the wet method, the water containing inorganic particles may be removed before adding the surface treatment agent. For example, a method of removing with stirring and heating in a solvent used for the surface treatment, a method of removing by azeotropic distillation with the solvent. May be used.

  In addition, the inorganic particles may be subjected to a surface treatment before the acceptor compound is provided. The surface treatment agent is selected from known materials. For example, a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, a surfactant, and the like can be given. In particular, a silane coupling agent is desirably used. Furthermore, a silane coupling agent having an amino group is also desirably used.

  Any material may be used as the silane coupling agent having an amino group. Specific examples include γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N -Β- (aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, and the like. However, it is not limited to these.

  Two or more silane coupling agents may be mixed and used. Examples of silane coupling agents that may be used in combination with the silane coupling agent having an amino group include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3 , 4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -Γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyl Examples include trimethoxysilane. However, it is not limited to these.

  As the surface treatment method, any known method can be used, but a dry method or a wet method is preferably used. Moreover, you may perform acceptor provision and surface treatment by a coupling agent etc. in parallel.

  Although the quantity of the silane coupling agent with respect to the inorganic particle in the undercoat layer 4 is set arbitrarily, 0.5 mass% or more and 10 mass% or less are desirable with respect to an inorganic particle.

  As the binder resin contained in the undercoat layer 4, any known resin can be used. For example, acetal resin such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester Resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, etc. These known polymer resin compounds, charge transporting resins having a charge transporting group, conductive resins such as polyaniline, and the like are used. Among these, resins that are insoluble in the upper coating solvent are preferably used, and phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, epoxy resins, and the like are particularly preferable. When these are used in combination of two or more, the mixing ratio is set as necessary.

  In addition, the ratio of the metal oxide and binder resin which provided acceptor property in the coating liquid for undercoat layer formation or an inorganic particle and binder resin is set arbitrarily.

Various additives may be used in the undercoat layer 4. As additives, known materials such as polycyclic condensation type, azo type electron transporting pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, silane coupling agents and the like are used. It is done. The silane coupling agent is used for the surface treatment of the metal oxide, but may be further added to the coating solution as an additive. Specific examples of the silane coupling agent used here include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ. -Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β -(Aminoethyl) -γ-aminopropylmethyldimethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane and the like.
Examples of zirconium chelate compounds include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl zirconium acetoacetate, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, naphthene. Zirconate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Examples of titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt , Titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, polyhydroxy titanium stearate and the like.

  Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.

  These compounds may be used alone or as a mixture or polycondensate of a plurality of compounds.

  The solvent for preparing the coating solution for forming the undercoat layer is selected from known organic solvents such as alcohols, aromatics, halogenated hydrocarbons, ketones, ketone alcohols, ethers, esters, etc. The Examples of the solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, Usual organic solvents such as dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene and toluene are used.

  Moreover, you may use the solvent used for these dispersion | distribution individually or in mixture of 2 or more types. When mixing, any solvent can be used as long as it can dissolve the binder resin as the mixed solvent.

  As a dispersion method, known methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker are used. Further, as the coating method used when the undercoat layer 4 is provided, usual methods such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method are used. Is used.

The undercoat layer 4 is formed on the conductive substrate 1 using the coating solution for forming the undercoat layer thus obtained.
The undercoat layer 4 preferably has a Vickers strength of 35 or more.
Further, the undercoat layer 4 may be set to any thickness, but the thickness is preferably 15 μm or more, and more preferably 15 μm or more and 50 μm or less.

  Further, the surface roughness (ten-point average roughness) of the undercoat layer 4 is from 1 / 4n (n is the refractive index of the upper layer) to 1 / 2λ of the exposure laser wavelength λ used to prevent moire images. Adjusted to In order to adjust the surface roughness, particles such as a resin may be added to the undercoat layer. As the resin particles, silicone resin particles, cross-linked polymethyl methacrylate resin particles and the like are used.

The undercoat layer 4 contains a binder resin and a conductive metal oxide, and has a light transmittance of 40% or less (more preferably 10% or more and 35% or less, more preferably 15%) with respect to light having a wavelength of 950 nm at a thickness of 20 μm. % Or more and 30% or less).
The light transmittance of the undercoat layer is measured as follows. The undercoat layer-forming coating solution is applied on a glass plate so that the thickness after drying is 20 μm, and after drying, the light transmittance of the film at a wavelength of 950 nm is measured using a spectrophotometer. For the light transmittance by the photometer, an apparatus name “Spectrophotometer (U-2000): manufactured by Hitachi, Ltd.” is used as a spectrophotometer.

  The light transmittance of the undercoat layer can be controlled by adjusting the dispersion time during dispersion using the roll mill, ball mill, vibration ball mill, attritor, sand mill, colloid mill, paint shaker, or the like. The dispersion time is not particularly limited, but is preferably 5 minutes to 1000 hours, and more preferably 30 minutes to 10 hours. When the dispersion time is increased, the light transmittance tends to decrease.

  Further, the undercoat layer may be polished for adjusting the surface roughness. As a polishing method, buffing, sandblasting, wet honing, grinding, or the like is used.

  The coated layer is dried to obtain an undercoat layer. Usually, the drying is performed at a temperature at which the solvent can be evaporated to form a film.

Charge generation layer The charge generation layer 2A is preferably a layer containing at least a charge generation material and a binder resin.
Examples of the charge generation material include azo pigments such as bisazo and trisazo, condensed aromatic pigments such as dibromoanthanthrone, perylene pigments, pyrrolopyrrole pigments, phthalocyanine pigments, zinc oxide, and trigonal selenium. Among these, metal and / or metal-free phthalocyanine pigments are desirable for near-infrared laser exposure. In particular, hydroxygallium disclosed in JP-A-5-263007, JP-A-5-279591, and the like. Phthalocyanine, chlorogallium phthalocyanine disclosed in JP-A-5-98181, dichlorotin phthalocyanine disclosed in JP-A-5-140472, JP-A-5-140473, etc., JP-A-4-189873, More preferred is titanyl phthalocyanine disclosed in JP-A-5-43823. For near-ultraviolet laser exposure, condensed aromatic pigments such as dibromoanthanthrone, thioindigo pigments, porphyrazine compounds, zinc oxide, and trigonal selenium are more desirable. As the charge generation material, an inorganic pigment is desirable when a light source with an exposure wavelength of 380 nm to 500 nm is used, and a metal and a metal-free phthalocyanine pigment are desirable when a light source with an exposure wavelength of 700 nm or less and 800 nm is used.

  As the charge generation material, it is desirable to use a hydroxygallium phthalocyanine pigment having a maximum peak wavelength in a range of 810 nm to 839 nm in a spectral absorption spectrum in a wavelength range of 600 nm to 900 nm. This hydroxygallium phthalocyanine pigment is different from the conventional V-type hydroxygallium phthalocyanine pigment, and the maximum peak wavelength of the spectral absorption spectrum is shifted to a shorter wavelength side than the conventional V-type hydroxygallium phthalocyanine pigment. .

The hydroxygallium phthalocyanine pigment having the maximum peak wavelength in the range of 810 nm to 839 nm is preferably in a specific range for the average particle size and in a specific range for the BET specific surface area. Specifically, the average particle size is desirably 0.20 μm or less, more desirably 0.01 μm or more and 0.15 μm or less, while the BET specific surface area is desirably 45 m ² / g or more. 50 m ² / g or more is more desirable, and 55 m ² / g or more and 120 m ² / g or less is particularly desirable. The average particle size is a volume average particle size (d50 average particle size) measured by a laser diffraction / scattering particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.). Moreover, it is the value measured by the nitrogen substitution method using the BET-type specific surface area measuring device (Shimadzu Corporation make: Flow soap II2300).

  The maximum particle size (maximum primary particle size) of the hydroxygallium phthalocyanine pigment is desirably 1.2 μm or less, more desirably 1.0 μm or less, and further desirably 0.3 μm or less. is there.

Further, the hydroxygallium phthalocyanine pigment preferably has an average particle size of 0.2 μm or less, a maximum particle size of 1.2 μm or less, and a specific surface area value of 45 m ² / g or more.

  In addition, the hydroxygallium phthalocyanine pigment described above has Bragg angles (2θ ± 0.2 °) of 7.5 °, 9.9 °, 12.5 °, and 16.5 in an X-ray diffraction spectrum using CuKα characteristic X-rays. It is desirable to have diffraction peaks at 3 °, 18.6 °, 25.1 ° and 28.3 °.

  The hydroxygallium phthalocyanine pigment preferably has a thermal weight reduction rate of 2.0% or more and 4.0% or less when heated from 25 ° C. to 400 ° C., and preferably 2.5% or more and 3.8%. % Or less is more desirable.

The binder resin used for the charge generation layer 2A is selected from a wide range of insulating resins, and selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. Also good. Desirable binder resins include polyvinyl butyral resins, polyarylate resins (polycondensates of bisphenols and aromatic divalent carboxylic acids, etc.), polycarbonate resins, polyester resins, phenoxy resins, vinyl chloride-vinyl acetate copolymers, polyamides. Resins, acrylic resins, polyacrylamide resins, polyvinyl pyridine resins, cellulose resins, urethane resins, epoxy resins, caseins, polyvinyl alcohol resins, polyvinyl pyrrolidone resins, and the like. These binder resins are used alone or in combination of two or more. The blending ratio of the charge generation material and the binder resin is preferably in the range of 10: 1 to 1:10 by mass ratio. Here, “insulating” means that the volume resistivity is 10 ¹³ Ωcm or more.

The charge generation layer 2A is formed using, for example, a coating liquid in which the charge generation material and the binder resin are dispersed in a solvent.
Solvents used for dispersion include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, and methylene chloride. , Chloroform, chlorobenzene, toluene and the like. These may be used alone or in admixture of two or more.

  Further, as a method for dispersing the charge generating material and the binder resin in the solvent, usual methods such as a ball mill dispersion method, an attritor dispersion method, and a sand mill dispersion method are used. Further, at the time of dispersion, it is effective that the average particle size of the charge generating material is 0.5 μm or less, desirably 0.3 μm or less, and more desirably 0.15 μm or less.

  Further, when forming the charge generation layer 2A, a usual method such as a blade coating method, a Mayer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method is used. .

  The film thickness of the charge generation layer 2A thus obtained is desirably 0.1 μm or more and 5.0 μm or less, and more desirably 0.2 μm or more and 2.0 μm or less.

Charge transport layer The charge transport layer 2B is preferably a layer containing at least a charge transport material and a binder resin, or a layer containing a polymer charge transport material.
Charge transport materials include quinone compounds such as p-benzoquinone, chloranil, bromanyl, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, xanthone compounds, benzophenone compounds , Electron transport compounds such as cyanovinyl compounds and ethylene compounds, triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, etc. Examples thereof include pore transporting compounds. These charge transport materials may be used alone or in combination of two or more, but are not limited thereto.

  As the charge transport material, from the viewpoint of charge mobility, a triarylamine derivative represented by the following structural formula (a-1) and a benzidine derivative represented by the following structural formula (a-2) are desirable.

(In Structural Formula (a-1), R ⁸ represents a hydrogen atom or a methyl group. N represents 1 or 2. Ar ⁶ and Ar ⁷ are each independently a substituted or unsubstituted aryl group, —C _6. H ₄ —C (R ⁹ ) ═C (R ¹⁰ ) (R ¹¹ ), or —C ₆ H ₄ —CH═CH—CH═C (R ¹² ) (R ¹³ ), wherein R ^{9 to} R ¹³ are Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, including a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms; A substituted amino group substituted with a group or an alkyl group having 1 to 3 carbon atoms.)

(In Structural Formula (a-2), R ¹⁴ and R ^{14 ′} may be the same or different and each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or 1 to 5 carbon atoms. R ¹⁵ , R ^{15 ′} , R ¹⁶ and R ^{16 ′} may be the same or different and each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or 1 carbon atom. Or more, an alkoxy group having 5 or less, an amino group substituted with an alkyl group having 1 to 2 carbon atoms, a substituted or unsubstituted aryl group, -C (R ¹⁷ ) = C (R ¹⁸ ) (R ¹⁹ ), or- CH = CH—CH═C (R ²⁰ ) (R ²¹ ), wherein R ^{17 to} R ²¹ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. And n are independent of each other 0 or 2 show the following integer.)

Here, among the triarylamine derivatives represented by the structural formula (a-1) and the benzidine derivatives represented by the structural formula (a-2), in particular, “—C ₆ H ₄ —CH═CH—CH Triarylamine derivatives having “═C (R ¹² ) (R ¹³ )” and benzidine derivatives having “—CH═CH—CH═C (R ²⁰ ) (R ²¹ )” are desirable.

  The binder resin used for the charge transport layer 2B is polycarbonate resin, polyester resin, polyarylate resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer. , Vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly- N-vinyl carbazole, polysilane, etc. are mentioned. Further, as described above, a polymer charge transport material such as a polyester-based polymer charge transport material disclosed in JP-A-8-176293 and JP-A-8-208820 may be used. These binder resins are used alone or in combination of two or more. The blending ratio of the charge transport material and the binder resin is desirably 10: 1 to 1: 5 by mass ratio.

  The binder resin is not particularly limited, but at least one of a polycarbonate resin having a viscosity average molecular weight of 50,000 to 80,000 and a polyarylate resin having a viscosity average molecular weight of 50,000 to 80,000 is desirable.

  In addition, a polymer charge transport material may be used as the charge transport material. As the polymer charge transporting material, known materials having charge transporting properties such as poly-N-vinylcarbazole and polysilane are used. In particular, polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 are desirable. The polymer charge transport material can be formed by itself, but may be formed by mixing with the binder resin.

  The charge transport layer 2B is formed using, for example, a charge transport layer forming coating solution containing the above-described constituent materials. Solvents used in the coating solution for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, and halogenation such as methylene chloride, chloroform and ethylene chloride. Ordinary organic solvents such as aliphatic hydrocarbons, cyclic ethers such as tetrahydrofuran and ethyl ether, or straight chain ethers may be used alone or in admixture of two or more. Moreover, a well-known method is used as a dispersion method of each said constituent material.

  Coating methods for coating the charge transport layer forming coating solution on the charge generation layer 2A include blade coating method, Mayer bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, A usual method such as a curtain coating method is used.

  The film thickness of the charge transport layer 2B is desirably 5 μm or more and 50 μm or less, and more desirably 10 μm or more and 30 μm or less.

-Protective layer The surface layer (protective layer 2C in the first embodiment) contains the following components (a) to (e).
(A) at least one substituent (a-1) selected from guanamine compounds and melamine compounds and at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH and —COOH (specific Charge transport material (a-2) having a substituent) and cross-linked product (b) Fluororesin particle (c) Oligomer containing fluorine atom (specific oligomer)
(D) Lower alcohol solvent having 6 or less carbon atoms (lower alcohol solvent)
(E) At least one solvent selected from ketone solvents, ether solvents, ester solvents and hydrocarbon solvents (other specific solvents)

(A-1) Guanamine compound and melamine compound First, the guanamine compound will be described.
The guanamine compound is a compound having a guanamine skeleton (structure), and examples thereof include acetoguanamine, benzoguanamine, formoguanamine, steroguanamine, spiroguanamine, and cyclohexylguanamine.

  The guanamine compound is particularly preferably at least one of a compound represented by the following general formula (A) and a multimer thereof. Here, the multimer is an oligomer polymerized using the compound represented by the general formula (A) as a structural unit, and the degree of polymerization thereof is, for example, 2 or more and 200 or less (preferably 2 or more and 100 or less). In addition, the compound shown by general formula (A) may be used individually by 1 type, but may use 2 or more types together.

In General Formula (A), R ¹ is a linear or branched alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, or 4 to 10 carbon atoms. The following substituted or unsubstituted alicyclic hydrocarbon groups are shown. R ^{2 to} R ⁵ each independently represent hydrogen, —CH ₂ —OH, or —CH ₂ —O—R ⁶ . R ⁶ represents hydrogen or a linear or branched alkyl group having 1 to 10 carbon atoms.

In general formula (A), the alkyl group represented by R ¹ has 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 5 carbon atoms. . The alkyl group may be linear or branched.

In general formula (A), the phenyl group represented by R ¹ has 6 to 10 carbon atoms, and more preferably 6 to 8 carbon atoms. Examples of the substituent substituted with the phenyl group include a methyl group, an ethyl group, and a propyl group.

In general formula (A), the alicyclic hydrocarbon group representing R ¹ has 4 to 10 carbon atoms, and more preferably 5 to 8 carbon atoms. Examples of the substituent substituted with the alicyclic hydrocarbon group include a methyl group, an ethyl group, and a propyl group.

In the general formula (A), in “—CH ₂ —O—R ⁶ ” representing R ^{2 to} R ⁵ , the alkyl group representing R ⁶ has 1 to 10 carbon atoms, and desirably has carbon atoms. 1 to 8 and more preferably 1 to 6 carbon atoms. The alkyl group may be linear or branched. Desirably, a methyl group, an ethyl group, a butyl group, etc. are mentioned.

As the compound represented by the general formula (A), it is particularly desirable that R ¹ represents a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, and R ^{2 to} R ⁵ are each independently —CH ₂ —O. It is a compound represented by —R ⁶ . R ⁶ is preferably selected from a methyl group and an n-butyl group.

  The compound represented by the general formula (A) is synthesized by a known method using, for example, guanamine and formaldehyde (for example, see Experimental Chemistry Course 4th edition, Vol. 28, page 430).

  Specific examples of the compound represented by the general formula (A) are shown below, but are not limited thereto. Moreover, although the following specific examples show the thing of a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient.

  Commercially available products of the compound represented by the general formula (A) include, for example, “Superbecamine (R) L-148-55, Superbecamine (R) 13-535, Superbecamine (R) L-145- 60, Super Becamine (R) TD-126 "or more manufactured by DIC Corporation," Nicarac BL-60, Nicalac BX-4000 "or more manufactured by Nippon Carbide Corporation, and the like.

  In addition, the compound represented by the general formula (A) (including multimers) can be used in a suitable solvent such as toluene, xylene, ethyl acetate, etc., in order to remove the influence of residual catalyst after synthesis or after purchasing a commercial product. It may be dissolved and washed with distilled water, ion exchange water or the like, or may be removed by treatment with an ion exchange resin.

Next, the melamine compound will be described.
The melamine compound is a melamine skeleton (structure), and is preferably at least one of a compound represented by the following general formula (B) and a multimer thereof. Here, the multimer is an oligomer obtained by polymerizing the compound represented by the general formula (B) as a structural unit as in the general formula (A), and the degree of polymerization thereof is, for example, 2 or more and 200 or less (preferably 2 or more and 100). The following). In addition, the compound shown by General formula (B) or its multimer may be used individually by 1 type, but may use 2 or more types together. Moreover, you may use together with the compound shown by the said general formula (A), or its multimer.

In General Formula (B), R ^{7 to} R ¹² each independently represent a hydrogen atom, —CH ₂ —OH, —CH ₂ —O—R ¹³ , —O—R ¹³ , and R ¹³ has 1 or more carbon atoms. The alkyl group which may branch 5 or less is shown. Examples of R ¹³ include a methyl group, an ethyl group, and a butyl group.

  The compound represented by the general formula (B) is synthesized by a known method using, for example, melamine and formaldehyde (for example, synthesized like the melamine resin described in Experimental Chemistry Course 4th edition, Volume 28, page 430). Synthesized.

  Specific examples of the compound represented by the general formula (B) are shown below, but are not limited thereto. Moreover, although the following specific examples show the thing of a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient.

  As a commercial item of the compound represented by the general formula (B), for example, Super Melami No. 90 (manufactured by NOF Corporation), Super Becamine (R) TD-139-60 (manufactured by DIC), Uban 2020 (Mitsui Chemicals), Sumitex Resin M-3 (Sumitomo Chemical Industries), Nicarak MW-30 (Japan) Carbide).

  In addition, the compound represented by the general formula (B) (including multimers) is dissolved in an appropriate solvent such as toluene, xylene or ethyl acetate after synthesis or after purchase of a commercial product in order to remove the influence of residual catalyst. It may be washed with distilled water, ion exchange water or the like, or may be removed by treatment with ion exchange resin.

  Here, the content of at least one selected from guanamine compounds and melamine compounds with respect to the solid content of the surface layer (protective layer 2C in the first embodiment) is preferably 0.1% by mass or more and 5% by mass or less. More preferably, it is 1 mass% or more and 3 mass% or less.

(A-2) Charge transporting material The charge transporting material has a charge having at least one substituent (specific substituent) selected from —OH, —OCH ₃ , —NH ₂ , —SH and —COOH. If it is a transportable material, it will not specifically limit. Particularly preferred are those having at least two (or three) specific substituents. Among them, a charge transport material having a structure represented by the following general formula (I) is preferably used.
^{_{F - ((- R 1 -X}} ) n1 (R 2) n3 -Y) n2 (I)
(In general formula (I), F represents an organic group derived from a compound having a hole transporting ability, and R ¹ and R ² each independently represents a linear or branched chain having 1 to 5 carbon atoms. N1 is 0 or 1, n2 is an integer of 1 to 4, n3 is 0 or 1, X is any one selected from an oxygen atom, a sulfur atom and a —NH— group, Represents —OH, —OCH ₃ , —NH ₂ , —SH and —COOH.)

  In general formula (I), as the compound having a hole transport ability in an organic group derived from a compound having a hole transport ability represented by F, an arylamine derivative is preferably exemplified. Preferred examples of the arylamine derivative include a triphenylamine derivative and a tetraphenylbenzidine derivative.

  The compound represented by the general formula (I) is preferably a compound represented by the following general formula (II).

(In general formula (II), Ar ^{1 to} Ar ⁴ may be the same or different and each independently represents a substituted or unsubstituted aryl group, and Ar ⁵ represents a substituted or unsubstituted aryl group or a substituted or unsubstituted aryl group. Represents a substituted arylene group, D represents — (— R ¹ —X) _n1 (R ² ) _n3 —Y, c represents 0 or 1 independently, k represents 0 or 1, and the total number of D Is from 1 to 4. R ¹ and R ² each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms, n1 represents 0 or 1, and n3 represents 0. Or 1 represents, X represents any selected from an oxygen atom, a sulfur atom and a —NH— group, and Y represents —OH, —OCH ₃ , —NH ₂ , —SH and —COOH.)

In the general formula (II), “— (— R ¹ —X) _n1 (R ² ) _n3 —Y” representing D is synonymous with the general formula (I), and R ¹ and R ² are each independently carbon. A linear or branched alkylene group having a number of 1 or more and 5 or less. N1 is preferably 1. X is preferably oxygen. Y is preferably a hydroxyl group.

  The total number of D in the general formula (II) corresponds to n2 in the general formula (I), preferably 2 or more and 4 or less, more preferably 3 or more and 4 or less. That is, in general formula (I) or general formula (II), it is preferable to have a specific substituent of 2 to 4 and more preferably 3 to 4 in one molecule.

In general formula (II), Ar ^{1 to} Ar ⁴ are preferably any of the following formulas (1) to (7). The following formulas (1) to (7) are shown together with “-(D) _c ” that can be linked to each of Ar ^{1 to} Ar ⁴ .

[In the formulas (1) to (7), R ⁹ is substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Represents one selected from the group consisting of a phenyl group, an unsubstituted phenyl group, and an aralkyl group having 7 to 10 carbon atoms, wherein R ^{10 to} R ¹² are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, carbon 1 selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom. Represents a seed, Ar represents a substituted or unsubstituted arylene group, D and c have the same meanings as “D” and “c” in formula (II), s represents 0 or 1, and t represents 1 3 or more It represents an integer. ]

  Here, as Ar in Formula (7), what is represented by following formula (8) or (9) is desirable.

[In formulas (8) and (9), R ¹³ and R ¹⁴ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. 1 represents one selected from the group consisting of a phenyl group substituted with, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms and a halogen atom, and t represents an integer of 1 to 3. ]

  Further, Z ′ in the formula (7) is preferably represented by any one of the following formulas (10) to (17).

[In the formulas (10) to (17), R ¹⁵ and R ¹⁶ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. 1 represents one selected from the group consisting of a phenyl group substituted with, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, W represents a divalent group, q and r each represent Represents an integer of 1 to 10, and t represents an integer of 1 to 3. ]

  W in the formulas (16) to (17) is preferably any one of divalent groups represented by the following (18) to (26). However, in formula (25), u represents an integer of 0 or more and 3 or less.

In general formula (II), Ar ⁵ is the aryl group of the above (1) to (7) exemplified in the description of Ar ^{1 to} Ar ⁴ when k is 0, and when k is 1, An arylene group obtained by removing one hydrogen atom from the above aryl groups (1) to (7) is desirable.

  Here, specific examples of the charge transporting material include the following.

  Here, the content rate of the charge transporting material with respect to the solid content of the surface layer (the protective layer 2C in the first embodiment) is 85% by mass or more, and more preferably 90% by mass or more.

(B) Fluorine resin particles The fluorine resin particles are not particularly limited. For example, polytetrafluoroethylene, perfluoroalkoxy fluorine resin, polychlorotrifluoroethylene, polyvinylidene fluoride, polydichlorodifluoroethylene, and tetrafluoroethylene. -Perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer, and the like. These may be used alone or in combination of two or more.

The fluororesin particles preferably have a molecular weight of 3,000 to 5,000,000. The particle diameter is preferably 0.01 μm or more and 10 μm or less, and more preferably 0.05 μm or more and 2.0 μm or less.
The particle diameter (average primary particle diameter) of the fluororesin particles is diluted with the same solvent as the dispersion in which the fluororesin particles are dispersed, using a laser diffraction particle size distribution analyzer LA-700 (manufactured by Horiba). The measured liquid was measured at a refractive index of 1.35.

  Commercially available fluororesin particles may be used. Examples of commercially available products include the Lubron series (Daikin Kogyo Co., Ltd.), the Teflon (registered trademark) series (Dupont), and the Dinion series (Sumitomo 3M). .

  The content of the fluororesin particles with respect to the total solid content of the protective layer 2C as the surface layer is preferably 1% by mass or more and 30% by mass or less, and more preferably 2% by mass or more and 20% by mass or less.

(C) Oligomer containing fluorine atom (specific oligomer)
Examples of the oligomer having a fluorine atom (specific oligomer) include oligomers of carboxylic acids having a —CF ₃ group as a terminal group.
Commercially available oligomers having a fluorine atom may be used. Examples of commercially available products include GF300, GF400 (manufactured by Toagosei Co., Ltd.), Surflon series (manufactured by AGC Seikekikal), Footage series (manufactured by Neos), and PF series. (Made by Kitamura Chemical Co., Ltd.), Mega Fuck Series (made by DIC), FC Series (made by 3M) and the like. These may be used alone or in combination of two or more.

In addition, the molecular weight of the oligomer having a fluorine atom is preferably 2000 or more and 250,000 or less, and more preferably 3000 or more and 150,000 or less.
The molecular weight of the oligomer having a fluorine atom is measured by gel permeation chromatography (GPC).

  In the protective layer 2C that is the surface layer, the content of the oligomer having fluorine atoms with respect to the fluororesin particles is preferably 0.5% by mass or more and 10% by mass or less, and more preferably 1% by mass or more and 7% by mass or less.

(D) a lower alcohol solvent and (e) other specific solvent, (d) a lower alcohol solvent having 6 or less carbon atoms (lower alcohol solvent), and (e) a ketone solvent, an ether solvent, an ester solvent, and At least one solvent selected from hydrocarbon solvents (other specific solvents) will be described.
In the present embodiment, (d) the lower alcohol solvent and (e) other specific solvent present in the surface layer of the photoreceptor are solvents used in the coating solution for forming the surface layer, It refers to what remains as a residual solvent without being completely evaporated even after the surface layer is dried and cured when the surface layer is formed.

・ Lower alcohol solvent with 6 or less carbon atoms (lower alcohol solvent)
Examples of the lower alcohol solvent having 6 or less carbon atoms include linear or cyclic alcohols such as methanol, ethanol, i-propanol, 2-butanol, n-pentanol, cyclopentanol, and ethylene glycol.
Among these, 2-butanol, n-pentanol, and cyclopentanol are particularly preferable.
The carbon number of the lower alcohol solvent is preferably 4 or more and 6 or less.
Such lower alcohol solvents may be used alone or in combination of two or more.

Ketone solvent Examples of the ketone solvent include cycloaliphatic ketones such as cyclobutanone, cyclopentanone, cyclohexanone, and cycloheptanone; linear or branched ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. .
Among these, cyclopentanone, methyl ethyl ketone, and methyl isobutyl ketone are particularly preferable.

-Ether solvent Examples of the ether solvent include cyclic or linear ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, and diethyl ether.
Among these, tetrahydrofuran and 2-methyltetrahydrofuran are particularly preferable.

-Ester solvent Examples of the ester solvent include esters such as butyl acetate and isobutyl acetate.

-Hydrocarbon solvent Examples of the hydrocarbon solvent include toluene, ethylbenzene, and the like.

  Such ketone solvents, ether solvents, ester solvents and hydrocarbon solvents may be used alone or in admixture of two or more.

-Solvent content, etc. In the coating liquid for forming the surface layer (in the first embodiment, the coating liquid for forming the protective layer 2C), the total amount of the solvent is 20% by mass or more with respect to the total amount of the coating liquid. The mass is preferably not more than mass%, more preferably not less than 30 mass% and not more than 50 mass%.

  The proportion of (d) the lower alcohol solvent in the total solvent in the coating solution for forming the surface layer is preferably 5% by mass or more and 80% by mass or less, while (e) the proportion of the other specific solvent is 20%. The mass is preferably 95% by mass or more and 95% by mass or less.

  The amount of residual solvent in the surface layer of the photoreceptor is preferably 1000 ppm or more and 40000 ppm or less, and more preferably 3000 ppm or more and 6000 ppm or less.

  Further, identification analysis and quantitative analysis of the solvent (residual solvent) contained in the surface layer of the photoreceptor are detected by, for example, gas chromatography. For gas chromatography, for example, HP6890 (manufactured by Agilent) and column HP-5MS (manufactured by Agilent) are used at an oven initial temperature of 45 ° C.

(Other compositions)
For the protective layer 2C, other thermosetting resins such as phenol resin, melamine resin, urea resin, alkyd resin, and benzoguanamine resin may be mixed and used together with a crosslinked product obtained by crosslinking a specific charge transporting material. . In addition, a compound having a larger number of functional groups in one molecule such as a spiroacetal guanamine resin (for example, “CTU-guanamine” (Ajinomoto Fine Techno Co., Ltd.)) may be copolymerized with the material in the crosslinked product.

  In addition, it is preferable to add a surfactant to the protective layer 2C, and the surfactant to be used is particularly a surfactant that includes at least one type of structure among a fluorine atom, an alkylene oxide structure, and a silicone structure. Although there is no restriction | limiting, What has multiple said structures is mentioned suitably.

  Various things are mentioned as surfactant which has a fluorine atom. Specific examples of the surfactant having a fluorine atom and an acrylic structure include Polyflow KL600 (manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF-351, EF-352, EF-801, EF-802, EF-601 (above, JEMCO Etc.). Examples of the surfactant having an acrylic structure mainly include those obtained by polymerizing or copolymerizing monomers such as acrylic or methacrylic compounds.

  Further, as the surfactant having a perfluoroalkyl group as a fluorine atom, specifically, perfluoroalkyl sulfonic acids (for example, perfluorobutane sulfonic acid, perfluorooctane sulfonic acid, etc.), perfluoroalkyl carboxylic acids (for example, , Perfluorobutanecarboxylic acid, perfluorooctanecarboxylic acid, etc.) and perfluoroalkyl group-containing phosphates. Perfluoroalkylsulfonic acids and perfluoroalkylcarboxylic acids may be salts thereof and amide-modified products thereof.

Examples of commercially available perfluoroalkyl sulfonic acids include Megafax F-114 (manufactured by DIC Corporation), F-top EF-101, EF102, EF-103, EF-104, EF-105, EF-112, and EF-. 121, EF-122A, EF-122B, EF-122C, EF-123A (manufactured by JEMCO), AK, 501 (manufactured by Neos) and the like.
Examples of commercially available products of perfluoroalkylcarboxylic acids include Megafac F-410 (manufactured by DIC Corporation), F-top EF-201, EF-204 (manufactured by JEMCO Corporation), and the like.
Commercially available perfluoroalkyl group-containing phosphate esters include MegaFac F-493 and F-494 (manufactured by DIC Corporation) F-top EF-123A, EF-123B, EF-125M, EF-132, ( As mentioned above, JEMCO Co., Ltd.) can be cited.

  Examples of the surfactant having an alkylene oxide structure include polyethylene glycol, polyether antifoaming agent, and polyether-modified silicone oil. Polyethylene glycol preferably has a number average molecular weight of 2000 or less. Polyethylene glycol having a number average molecular weight of 2000 or less includes polyethylene glycol 2000 (number average molecular weight 2000), polyethylene glycol 600 (number average molecular weight 600), polyethylene glycol 400 (number average molecular weight 400), polyethylene glycol 200 (number average molecular weight 200). ) And the like.

  Moreover, as a polyether antifoamer, PE-M, PE-L (above, Wako Pure Chemical Industries Ltd. make), antifoam No. 1. Antifoaming agent No. 1 5 (above, manufactured by Kao Corporation).

  Examples of the surfactant having a silicone structure include general silicone oils such as dimethyl silicone, methylphenyl silicone, diphenyl silicone and derivatives thereof.

  Further, as the surfactant having both a fluorine atom and an alkylene oxide structure, those having an alkylene oxide structure or a polyalkylene structure in the side chain, or substituted at the terminal of the alkylene oxide or polyalkylene oxide structure with a substituent containing fluorine And the like. Specific examples of the surfactant having an alkylene oxide structure include, for example, MegaFuck F-443, F-444, F-445, F-446 (above, manufactured by DIC Corporation), POLY FOX PF636, PF6320, and PF6520. , PF656 (made by Kitamura Chemical Co., Ltd.) and the like.

  As surfactants having both an alkylene oxide structure and a silicone structure, KF351 (A), KF352 (A), KF353 (A), KF354 (A), KF355 (A), KF615 (A), KF618, KF945 (A), KF6004 (above, manufactured by Shin-Etsu Chemical Co., Ltd.), TSF4440, TSF4445, TSF4450, TSF4446, TSF4452, TSF4453, TSF4460 (above, manufactured by GE Toshiba Silicon), BYK-300, 302, 306, 307, 310, 315, 320, 322, 323, 325, 330, 331, 333, 337, 341, 344, 345, 346, 347, 348, 370, 375, 377, 378, UV3500, UV3510, UV3570, etc. Made emissions Co., Ltd.) and the like.

  The content of the surfactant is desirably 0.01% by mass or more and 1% by mass or less, more desirably 0.02% by mass or more and 0.5% by mass or less with respect to the total solid content of the protective layer.

  Further, the protective layer 2C may be further mixed with another coupling agent or a fluorine compound. As this compound, various silane coupling agents and commercially available silicone hard coat agents are used.

  As the silane coupling agent, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, and the like are used. As a commercially available hard coat agent, KP-85, X-40-9740, X-8239 (manufactured by Shin-Etsu Silicone), AY42-440, AY42-441, AY49-208 (manufactured by Toray Dow Corning) Etc. are used. In order to impart water repellency and the like, (tridecafluoro-1,1,2,2-tetrahydrooctyl) triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, 3- (hepta) Fluoroisopropoxy) propyltriethoxysilane, 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorooctyl Fluorine-containing compounds such as triethoxysilane may be added. Although the silane coupling agent is used in an arbitrary amount, the amount of the fluorine-containing compound is desirably 0.25 times or less by mass with respect to the compound not containing fluorine.

Further, a resin that dissolves in alcohol may be added to the protective layer. Here, the alcohol-soluble resin means a resin that can be dissolved by 1% by mass or more in an alcohol having 5 or less carbon atoms. Examples of resins that are soluble in alcohol solvents include polyvinyl acetal resins such as polyvinyl butyral resin, polyvinyl formal resin, and partially acetalized polyvinyl acetal resin in which a part of butyral is modified with formal or acetoacetal (for example, manufactured by Sekisui Chemical Co., Ltd.) ESREC B, K, etc.), polyamide resin, cellulose resin, polyvinylphenol resin and the like. In particular, polyvinyl acetal resin and polyvinyl phenol resin are desirable.
The resin preferably has a weight average molecular weight of 2,000 to 100,000, and more preferably 5,000 to 50,000. The amount of the resin added is preferably 1% by mass or more and 40% by mass or less, more preferably 1% by mass or more and 30% by mass or less, and further preferably 5% by mass or more and 20% by mass or less.

  An antioxidant may be added to the protective layer 2C. Antioxidants are preferably hindered phenols or hindered amines, organic sulfur antioxidants, phosphite antioxidants, dithiocarbamate antioxidants, thiourea antioxidants, benzimidazole antioxidants. , Etc., may be used. The addition amount of the antioxidant is preferably 20% by mass or less, and more preferably 10% by mass or less.

  Examples of the hindered phenol antioxidant include 2,6-di-t-butyl-4-methylphenol, 2,5-di-t-butylhydroquinone, N, N′-hexamethylene bis (3,5-di). -T-butyl-4-hydroxyhydrocinnamide, 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 2,4-bis [(octylthio) methyl] -o-cresol, 2,6-di-t-butyl-4-ethylphenol, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol) 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 2,5-di-t-amylhydroquinone, 2-t-butyl-6- (3-butyl-2- Dorokishi-5-methylbenzyl) -4-methylphenyl acrylate, 4,4'-butylidene bis (3-methyl -6-t-butylphenol) and the like.

  Furthermore, various particles may be added to the protective layer. An example of the particles is silicon-containing particles. Silicon-containing particles are particles containing silicon as a constituent element, and specific examples include colloidal silica and silicone particles. The colloidal silica used as the silicon-containing particles is obtained by dispersing silica having an average particle diameter of 1 nm or more and 100 nm or less, preferably 10 nm or more and 30 nm or less in an organic solvent such as an acidic or alkaline aqueous dispersion, alcohol, ketone, or ester. A commercially available product may be used. The solid content of the colloidal silica in the protective layer 2C is not particularly limited, but is 0.1% by mass or more and 50% by mass or less, preferably 0.1% by mass based on the total solid content of the protective layer. It is used in the range of mass% to 30 mass%.

  The silicone particles used as the silicon-containing particles may be selected from silicone resin particles, silicone rubber particles, and silicone surface-treated silica particles, and commercially available particles may be used. These silicone particles are spherical, and the average particle size is desirably 1 nm or more and 500 nm or less, and more desirably 10 nm or more and 100 nm or less. Silicone particles are particles that are chemically inert and have excellent dispersibility in resins. The content of the silicone particles in the protective layer is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.5% by mass or more and 10% by mass or less, based on the total solid content of the protective layer. .

Other particles include fluorine-based particles such as ethylene tetrafluoride, ethylene trifluoride, propylene hexafluoride, vinyl fluoride, and vinylidene fluoride, and “8th Polymer Material Forum Lecture Proceedings p89”. As shown, particles made of a resin obtained by copolymerizing a fluororesin and a monomer having a hydroxyl group, ZnO—Al ₂ O ₃ , SnO ₂ —Sb ₂ O ₃ , In ₂ O ₃ —SnO ₂ , ZnO ₂ —TiO ₂ , ZnO Examples thereof include semiconductive metal oxides such as —TiO ₂ , MgO—Al ₂ O ₃ , FeO—TiO ₂ , TiO ₂ , SnO ₂ , In ₂ O ₃ , ZnO, and MgO.
Oil such as silicone oil may be added. Silicone oils include silicone oils such as dimethylpolysiloxane, diphenylpolysiloxane, and phenylmethylsiloxane; amino-modified polysiloxane, epoxy-modified polysiloxane, carboxyl-modified polysiloxane, carbinol-modified polysiloxane, methacryl-modified polysiloxane, mercapto-modified poly Reactive silicone oils such as siloxane and phenol-modified polysiloxane; cyclic dimethylcyclosiloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane; 1,3,5- Trimethyl-1,3,5-triphenylcyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclo Cyclic methylphenylcyclosiloxanes such as trasiloxane, 1,3,5,7,9-pentamethyl-1,3,5,7,9-pentaphenylcyclopentasiloxane; cyclic phenylcyclosiloxanes such as hexaphenylcyclotrisiloxane Fluorine-containing cyclosiloxanes such as (3,3,3-trifluoropropyl) methylcyclotrisiloxane; hydrosilyl group-containing cyclosiloxanes such as methylhydrosiloxane mixtures, pentamethylcyclopentasiloxane, and phenylhydrocyclosiloxane; penta And vinyl group-containing cyclosiloxanes such as vinylpentamethylcyclopentasiloxane.

  Moreover, you may add a metal, a metal oxide, carbon black, etc. to a protective layer. Examples of the metal include aluminum, zinc, copper, chromium, nickel, silver and stainless steel, or those obtained by depositing these metals on the surface of plastic particles. Examples of the metal oxide include zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, indium oxide doped with tin, tin oxide doped with antimony and tantalum, and zirconium oxide doped with antimony. . These may be used alone or in combination of two or more. When two or more types are used in combination, they may be simply mixed, or may be in the form of a solid solution or fusion. The average particle size of the conductive particles is preferably 0.3 μm or less, particularly preferably 0.1 μm or less.

  The protective layer 2C may contain a curing catalyst for accelerating the curing of the guanamine compound, the melamine compound and the charge transporting material. An acid catalyst is preferably used as the curing catalyst. Acid-based catalysts include acetic acid, chloroacetic acid, trichloroacetic acid, trifluoroacetic acid, oxalic acid, maleic acid, malonic acid, lactic acid and other aliphatic carboxylic acids, benzoic acid, phthalic acid, terephthalic acid, trimellitic acid, etc. Aromatic carboxylic acids, methane sulfonic acids, dodecyl sulfonic acids, benzene sulfonic acids, aliphatics such as dodecyl benzene sulfonic acids, naphthalene sulfonic acids, and aromatic sulfonic acids are used, but sulfur-containing materials should be used. desirable.

  The sulfur-containing material as the curing catalyst is desirably one that exhibits acidity at room temperature (for example, 25 ° C.) or after heating, and is most desirably at least one of organic sulfonic acids and derivatives thereof. The presence of these catalysts in the protective layer 2C is easily confirmed by energy dispersive X-ray analysis (EDS), X-ray photoelectron spectroscopy (XPS), or the like.

  Examples of the organic sulfonic acid and / or a derivative thereof include p-toluenesulfonic acid, dinonylnaphthalenesulfonic acid (DNNSA), dinonylnaphthalenedisulfonic acid (DNNDSA), dodecylbenzenesulfonic acid, and phenolsulfonic acid. Among these, p-toluenesulfonic acid and dodecylbenzenesulfonic acid are desirable. Moreover, as long as it can dissociate in a curable resin composition, you may use an organic sulfonate.

Further, a so-called thermal latent catalyst, which has a high catalytic ability when heated, may be used.
As a heat latent catalyst, for example, a microcapsule in which an organic sulfone compound or the like is encapsulated in a polymer form, an adsorbed acid or the like on a pore compound such as zeolite, and a proton acid and / or proton acid derivative is blocked with a base Thermal latent proton acid catalyst, proton acid and / or proton acid derivative esterified with primary or secondary alcohol, proton acid and / or proton acid derivative blocked with vinyl ethers and / or vinyl thioethers , Boron trifluoride monoethylamine complex, boron trifluoride pyridine complex, and the like.

Of these, a protonic acid and / or a protonic acid derivative blocked with a base is desirable.
As the protonic acid of the heat latent protonic acid catalyst, sulfuric acid, hydrochloric acid, acetic acid, formic acid, nitric acid, phosphoric acid, sulfonic acid, monocarboxylic acid, polycarboxylic acids, propionic acid, oxalic acid, benzoic acid, acrylic acid, methacrylic acid, Itaconic acid, phthalic acid, maleic acid, benzenesulfonic acid, o, m, p-toluenesulfonic acid, styrenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, decylbenzenesulfonic acid, undecylbenzenesulfonic acid, Examples include tridecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, dodecylbenzenesulfonic acid and the like. In addition, as protonic acid derivatives, neutralized products such as alkali metal salts or alkaline earth metal salts of protonic acids such as sulfonic acid and phosphoric acid, and polymer compounds in which a protonic acid skeleton is introduced into the polymer chain (polyvinylsulfone) Acid, etc.). Examples of the base that blocks the protonic acid include amines.

  Amines are classified as primary, secondary or tertiary amines. There is no restriction | limiting in particular and any may be used.

  Examples of the primary amine include methylamine, ethylamine, propylamine, isopropylamine, n-butylamine, isobutylamine, t-butylamine, hexylamine, 2-ethylhexylamine, secondary butylamine, allylamine, and methylhexylamine.

  As secondary amines, dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, diisobutylamine, di-t-butylamine, dihexylamine, di (2-ethylhexyl) amine, N-isopropyl N-isobutylamine , Di (2-ethylhexyl) amine, disecondary butylamine, diallylamine, N-methylhexylamine, 3-pipecoline, 4-pipecoline, 2,4-lupetidine, 2,6-lupetidine, 3,5-lupetidine, morpholine, N -Methylbenzylamine and the like.

  As tertiary amines, trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, triisobutylamine, tri-t-butylamine, trihexylamine, tri (2-ethylhexyl) amine, N-methylmorpholine, N, N-dimethylallylamine, N-methyldiallylamine, triallylamine, N, N-dimethylallylamine, N, N, N ′, N′-tetramethyl-1,2-diaminoethane, N, N, N ′, N '-Tetramethyl-1,3-diaminopropane, N, N, N', N'-tetraallyl-1,4-diaminobutane, N-methylpiperidine, pyridine, 4-ethylpyridine, N-propyldiallylamine, 3- Dimethylaminopropanol, 2-ethylpyrazine, 2,3-di Tilpyrazine, 2,5-dimethylpyrazine, 2,4-lutidine, 2,5-lutidine, 3,4-lutidine, 3,5-lutidine, 2,4,6-collidine, 2-methyl-4-ethylpyridine, 2-methyl-5-ethylpyridine, N, N, N ′, N′-tetramethylhexamethylenediamine, N-ethyl-3-hydroxypiperidine, 3-methyl-4-ethylpyridine, 3-ethyl-4-methyl Pyridine, 4- (5-nonyl) pyridine, imidazole, N-methylpiperazine and the like can be mentioned.

Commercially available products include “NACURE2501” (toluenesulfonic acid dissociation, methanol / isopropanol solvent, pH 6.0 to pH 7.2, dissociation temperature 80 ° C.), “NACURE2107” (p-toluenesulfonic acid dissociation, manufactured by King Industries, Inc. Isopropanol solvent, pH 8.0 to pH 9.0, dissociation temperature 90 ° C.) “NACURE 2500” (p-toluenesulfonic acid dissociation, isopropanol solvent, pH 6.0 to pH 7.0, dissociation temperature 65 ° C.), “NACURE 2530” (P-toluenesulfonic acid dissociation, methanol / isopropanol solvent, pH 5.7 to pH 6.5, dissociation temperature 65 ° C.), “NACURE2547” (p-toluenesulfonic acid dissociation, aqueous solution, pH 8.0 to pH 9.0, Dissociation temperature 107 ), “NACURE2558” (p-toluenesulfonic acid dissociation, ethylene glycol solvent, pH 3.5 to pH4.5, dissociation temperature 80 ° C.), “NACUREXP-357” (p-toluenesulfonic acid dissociation, methanol solvent, pH 2. 0 to pH 4.0, dissociation temperature 65 ° C.) “NACUREXP-386” (p-toluenesulfonic acid dissociation, aqueous solution, pH 6.1 to pH 6.4, dissociation temperature 80 ° C.), “NACUREX C-2211” (p -Toluenesulfonic acid dissociation, pH 7.2 to pH 8.5, dissociation temperature 80 ° C.), “NACURE 5225” (dodecylbenzenesulfonic acid dissociation, isopropanol solvent, pH 6.0 to pH 7.0, dissociation temperature 120 ° C.), “ NACURE 5414 "(dodecylbenzenesulfonic acid dissociation, key Ren solvent, dissociation temperature 120 ° C.), “NACURE 5528” (dodecylbenzenesulfonic acid dissociation, isopropanol solvent, pH 7.0 to pH 8.0, dissociation temperature 120 ° C.), “NACURE 5925” (dodecylbenzenesulfonic acid dissociation, pH 7.0) PH 7.5 or less, dissociation temperature 130 ° C., “NACURE 1323” (disinyl naphthalene sulfonic acid dissociation, xylene solvent, pH 6.8 to pH 7.5, dissociation temperature 150 ° C.), “NACURE 1419” (dinonyl naphthalene sulfonic acid Dissociation, xylene / methyl isobutyl ketone solvent, dissociation temperature 150 ° C.), “NACURE1557” (dinonylnaphthalenesulfonic acid dissociation, butanol / 2-butoxyethanol solvent, pH 6.5 to pH 7.5, dissociation temperature 150 ° C.), “ NA CUREX 49-110 ”(dinonyl naphthalene disulfonic acid dissociation, isobutanol / isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 90 ° C.),“ NACURE 3525 ”(dinonyl naphthalene disulfonic acid dissociation, isobutanol / isopropanol solvent, pH 7.0 to pH 8.5, dissociation temperature 120 ° C., “NACUREXP-383” (dinonyl naphthalene disulfonic acid dissociation, xylene solvent, dissociation temperature 120 ° C.), “NACURE 3327” (dinonyl naphthalene disulfonic acid dissociation, isobutanol / Isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 150 ° C.), “NACURE4167” (phosphoric acid dissociation, isopropanol / isobutanol solvent, pH 6.8 to pH 7.3, dissociation temperature 80 ), “NACUREXP-297” (phosphoric acid dissociation, water / isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 90 ° C., “NACURE 4575” (phosphoric acid dissociation, pH 7.0 to pH 8.0, dissociation temperature) 110 ° C.).
These thermal latent catalysts may be used alone or in combination of two or more.

  Here, the blending amount of the catalyst is desirably in the range of 0.1% by mass or more and 10% by mass or less with respect to the total solid content excluding the fluororesin particles and the oligomer containing fluorine atoms in the coating solution, and particularly 0. .1% by mass to 5% by mass is desirable.

(Method for forming surface layer)
Here, as an example of a method for forming the surface layer of the photoconductor in the present embodiment, a method for forming the protective layer 2C, which is the surface layer in the photoconductor of the first aspect, will be described.
First, in the method for producing the photoreceptor of the first aspect, the conductive substrate 1 in which layers other than the surface layer (that is, the protective layer 2C) (that is, the undercoat layer 4, the charge generation layer 2A, the charge transport layer 2B, and the like) are formed. And (a) at least one selected from a guanamine compound and a melamine compound (a-1), and selected from —OH, —OCH ₃ , —NH ₂ , —SH and —COOH A charge transport material (a-2) having at least one substituent (specific substituent), (b) fluororesin particles, (c) an oligomer containing a fluorine atom (specific oligomer), and (d) ) A lower alcohol solvent having 6 or less carbon atoms (lower alcohol solvent) and (e) at least one solvent selected from ketone solvents, ether solvents, ester solvents and hydrocarbon solvents (other specific solvents) And With a coating solution was coated on the conductive substrate, having a surface layer forming step, forming the surface layer (i.e. the protective layer 2C) polymerized.

  As a coating method of the film forming coating solution for forming the protective layer 2C as the surface layer, push-up coating method, ring coating method, blade coating method, Meyer bar coating method, spray coating method, dip coating method, bead Examples of the method include a coating method, an air knife coating method, a curtain coating method, and an inkjet coating method. After coating, for example, the protective layer 2C can be obtained by heating at a temperature of 100 ° C. to 170 ° C. and curing (crosslinking).

  In the present embodiment, the thickness of the surface layer is preferably 5 μm or more and 20 μm or less, more preferably 7 μm or more and 15 μm or less.

Here, in the photoreceptor of the first aspect, the example of the function separation type having the charge generation layer 2A and the charge transport layer 2B has been described. However, the single layer type photosensitive layer (a layer having charge generation ability and charge transport ability) is described. ), The content of the charge generating material in the single-layer type photosensitive layer is preferably 10% by mass to 85% by mass, and more preferably 20% by mass to 50% by mass. In addition, the content of the charge transport material is desirably 5% by mass or more and 50% by mass or less.
The method for forming the single-layer type photosensitive layer is performed according to the method for forming the charge generation layer 2A and the charge transport layer 2B.
The film thickness of the single-layer type photosensitive layer is preferably from 5 μm to 50 μm, and more preferably from 10 μm to 40 μm.

[Photoreceptor of Second Embodiment: Surface Layer = Charge Transport Layer]
As shown in FIG. 2, the photoreceptor of the second mode, which is an example in the present embodiment, is a layer in which an undercoat layer 4, a charge generation layer 2A, and a charge transport layer 2B are laminated in this order on a conductive substrate 1. The charge transport layer 2B is a surface layer.

  As the conductive substrate 1, the undercoat layer 4, and the charge generation layer 2A in the photoreceptor of the second embodiment, the conductive substrate 1, the undercoat layer 4, the charge in the photoreceptor of the first embodiment shown in FIG. The generation layer 2A is applied as it is. As the charge transport layer 2B in the photoconductor of the second mode, the protective layer 2C in the photoconductor of the first mode shown in FIG. 1 is applied as it is.

[Image forming apparatus]
FIG. 3 is a schematic configuration diagram illustrating the image forming apparatus according to the present embodiment. As shown in FIG. 3, the image forming apparatus 100 includes a process cartridge 300 including an electrophotographic photosensitive member 7, an exposure device 9, a transfer device 40, and an intermediate transfer member 50. In the image forming apparatus 100, the exposure device 9 is disposed at a position where the electrophotographic photosensitive member 7 can be exposed from the opening of the process cartridge 300, and the transfer device 40 is interposed between the electrophotographic photosensitive member via the intermediate transfer member 50. 7, and a part of the intermediate transfer member 50 is disposed in contact with the electrophotographic photosensitive member 7.

  A process cartridge 300 in FIG. 3 integrally supports an electrophotographic photosensitive member 7, a charging device 8, a developing device 11, and a cleaning device 13 in a housing. The cleaning device 13 has a cleaning blade 131 (blade member) made of an elastic material such as rubber, and the cleaning blade 131 is arranged so that the edge of one end thereof is in contact with the surface of the electrophotographic photosensitive member 7. A method of removing a developer such as toner adhered to the surface of the photographic photoreceptor 7 is applied. In addition to this, a known cleaning method such as a method using a cleaning brush using conductive plastic is used.

  Further, an example is shown in which a fibrous member 132 (roll shape) for supplying the lubricant 14 to the surface of the photoreceptor 7 and a fibrous member 133 (flat brush shape) for assisting cleaning are used. It may be used accordingly.

  As the charging device 8, for example, a contact type charger using a conductive or semiconductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube or the like is used. Further, a non-contact type roller charger, a known charger such as a scorotron charger using a corona discharge or a corotron charger may be used.

  Although not shown, a photosensitive member heating member for raising the temperature of the electrophotographic photosensitive member 7 and reducing the relative temperature may be provided around the electrophotographic photosensitive member 7.

  Examples of the exposure apparatus 9 include optical system devices that expose the surface of the photoconductor 7 with light such as semiconductor laser light, LED light, and liquid crystal shutter light in a desired image-like manner. The wavelength of the light source is in the spectral sensitivity region of the photoreceptor. As the wavelength of the semiconductor laser, near infrared having an oscillation wavelength near 780 nm is the mainstream. However, the wavelength is not limited to this, and a laser having an oscillation wavelength of 600 nm or a laser having an oscillation wavelength of 400 nm to 450 nm may be used as a blue laser. In addition, a surface-emitting type laser light source that can output a multi-beam is also effective for forming a multicolor image.

  As the developing device 11, for example, a general developing device that performs development by bringing a magnetic or non-magnetic one-component developer or two-component developer into contact or non-contact with each other may be used. The developing device is not particularly limited as long as it has the functions described above, and is selected according to the purpose. For example, a known developing device having a function of adhering the one-component developer or the two-component developer to the photoreceptor 7 using a brush, a roller, or the like can be used. Among these, those using a developing roller holding the developer on the surface are desirable.

Hereinafter, the toner used in the developing device 11 will be described.
The toner used in the image forming apparatus of this embodiment has an average shape factor ((ML ² / A) × (π / 4) × 100, where ML represents the maximum length of the particles, and A represents the projected area of the particles. Is preferably from 100 to 150, more preferably from 105 to 145, and even more preferably from 110 to 140. Further, the toner preferably has a volume average particle size of 3 μm to 12 μm, and more preferably 3.5 μm to 9 μm.

  The toner is not particularly limited by the production method. For example, a kneading and pulverizing method in which a binder resin, a colorant and a release agent, and a charge control agent are further added, kneaded, pulverized, and classified; A method of changing the shape of particles obtained by the method by mechanical impact force or thermal energy; a dispersion monomer formed by emulsion polymerization of a polymerizable monomer of a binder resin, a colorant and a release agent In addition, an emulsion polymerization aggregation method for obtaining toner particles by mixing a dispersion liquid such as a charge control agent and aggregating and heat-fusing to obtain toner particles; a polymerizable monomer for obtaining a binder resin, a colorant and a release agent Suspension polymerization method in which a solution of an agent, a charge control agent, etc. is suspended in an aqueous solvent for polymerization; a binder resin, a coloring agent, a release agent, and a solution of a charge control agent, etc., in an aqueous solvent Toner produced by the suspension method, etc. It is use.

  Further, a known method such as a production method in which the toner obtained by the above method is used as a core, and agglomerated particles are further adhered and heated and fused to give a core-shell structure is used. The toner production method is preferably a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method in which an aqueous solvent is used from the viewpoint of shape control and particle size distribution control, and an emulsion polymerization aggregation method is particularly desirable.

  The toner base particles desirably contain a binder resin, a colorant, and a release agent, and may further contain silica or a charge control agent.

  Binder resins used for toner base particles include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, etc. Α-methylene aliphatics such as vinyl esters, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate Homopolymers and copolymers of monocarboxylic acid esters, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone , Polyester resins by copolymerization of dicarboxylic acids and diols.

  Particularly representative binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. A polymer, polyethylene, a polypropylene, a polyester resin etc. are mentioned. Further, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like can be mentioned.

  In addition, as colorants, magnetic powders such as magnetite and ferrite, carbon black, aniline blue, caryl blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, Lamp Black, Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 is exemplified as a typical example.

  Typical examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, Fischer tropic wax, montan wax, carnauba wax, rice wax, and candelilla wax.

  As the charge control agent, known ones are used, and azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups are used. When toner is manufactured by a wet manufacturing method, it is desirable to use a material that is difficult to dissolve in water. The toner may be either a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material.

  The toner used in the developing device 11 is manufactured by mixing the toner base particles and the external additive with a Henschel mixer or a V blender. Further, when the toner base particles are produced by a wet method, they may be externally added by a wet method.

  Lubricating particles may be added to the toner used in the developing device 11. Lubricating particles include solid lubricants such as graphite, molybdenum disulfide, talc, fatty acids and fatty acid metal salts, low molecular weight polyolefins such as polypropylene, polyethylene and polybutene, silicones having a softening point upon heating, oleic amides , Erucic acid amide, ricinoleic acid amide, stearic acid amide and other aliphatic amides, carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil and other plant waxes, beeswax animal wax, montan wax, ozokerite , Ceresin, paraffin wax, microcrystalline wax, minerals such as Fischer-Tropsch wax, petroleum wax, and modified products thereof. These are used individually by 1 type or in combination of 2 or more types. However, the average particle size is preferably in the range of 0.1 μm or more and 10 μm or less, and those having the above chemical structure may be pulverized to make the particle sizes uniform. The amount added to the toner is desirably in the range of 0.05% by mass to 2.0% by mass, and more desirably in the range of 0.1% by mass to 1.5% by mass.

  To the toner used in the developing device 11, inorganic particles, organic particles, composite particles obtained by attaching inorganic particles to the organic particles, or the like may be added.

  Inorganic particles include silica, alumina, titania, zirconia, barium titanate, aluminum titanate, strontium titanate, magnesium titanate, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, Various inorganic oxides such as manganese oxide, boron oxide, silicon carbide, boron carbide, titanium carbide, silicon nitride, titanium nitride, and boron nitride, nitrides, borides, and the like are preferably used.

  In addition, the inorganic particles may be mixed with titanium coupling agents such as tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, bis (dioctylpyrophosphate) oxyacetate titanate, γ- (2- Aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxy Silane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane The treatment may be performed with a silane coupling agent such as run, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, and p-methylphenyltrimethoxysilane. In addition, those hydrophobized with higher fatty acid metal salts such as silicone oil, aluminum stearate, zinc stearate, calcium stearate and the like are also desirably used.

  Examples of the organic particles include styrene resin particles, styrene acrylic resin particles, polyester resin particles, and urethane resin particles.

  The particle diameter is preferably a number average particle diameter of 5 nm to 1000 nm, more preferably 5 nm to 800 nm, and even more preferably 5 nm to 700 nm. Moreover, it is desirable that the sum of the addition amounts of the above-described particles and the lubricating particles is 0.6% by mass or more.

  As the other inorganic oxide added to the toner, it is desirable to use a small-diameter inorganic oxide having a primary particle size of 40 nm or less, and further add an inorganic oxide having a larger diameter. Known inorganic oxide particles are used, but it is desirable to use silica and titanium oxide in combination.

  Moreover, you may surface-treat about a small diameter inorganic particle. Furthermore, it is also desirable to add carbonates such as calcium carbonate and magnesium carbonate and inorganic minerals such as hydrotalcite.

  In addition, the color toner for electrophotography is used by mixing with a carrier. As the carrier, iron powder, glass beads, ferrite powder, nickel powder, or those coated with a resin are used. The mixing ratio with the carrier is set as necessary.

  As the transfer device 40, for example, a contact transfer charger using a belt, a roller, a film, a rubber blade, etc., or a known transfer charger such as a scorotron transfer charger using a corona discharge or a corotron transfer charger. Can be mentioned.

  As the intermediate transfer member 50, a belt-like member (intermediate transfer belt) made of polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber or the like having semiconductivity is used. Further, as the form of the intermediate transfer member 50, a drum-like one is used in addition to the belt-like shape.

  In addition to the above-described devices, the image forming apparatus 100 may include, for example, a light neutralizing device that performs light neutralization on the photoconductor 7.

  FIG. 4 is a schematic cross-sectional view showing an image forming apparatus according to another embodiment. As shown in FIG. 4, the image forming apparatus 120 is a tandem multicolor image forming apparatus equipped with four process cartridges 300. In the image forming apparatus 120, four process cartridges 300 are arranged in parallel on the intermediate transfer member 50, and one electrophotographic photosensitive member is used for each color. The image forming apparatus 120 has the same configuration as the image forming apparatus 100 except that it is a tandem system.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example and a comparative example, this invention is not limited to a following example at all. In the following, “part” is based on mass unless otherwise specified.

<Example 1>
(Formation of undercoat layer)
100 parts of zinc oxide (average particle size 70 nm: manufactured by Teika: specific surface area value 15 m ² / g) is stirred and mixed with 500 parts of tetrahydrofuran, and 1.3 parts of a silane coupling agent (KBM503: manufactured by Shin-Etsu Chemical Co., Ltd.) is added. Stir for 2 hours. Thereafter, toluene was distilled off under reduced pressure and baked at 120 ° C. for 3 hours to obtain a silane coupling agent surface-treated zinc oxide.
110 parts of the surface-treated zinc oxide was stirred and mixed with 500 parts of tetrahydrofuran, a solution prepared by dissolving 0.6 part of alizarin in 50 parts of tetrahydrofuran was added, and the mixture was stirred at 50 ° C. for 5 hours. Then, the zinc oxide to which alizarin was imparted by filtration under reduced pressure was filtered off, and further dried at 60 ° C. under reduced pressure to obtain alizarin imparted zinc oxide.

60 parts of this alizarin-provided zinc oxide, 13.5 parts of a curing agent (blocked isocyanate, Sumidur 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) and 15 parts of butyral resin (ESREC BM-1, manufactured by Sekisui Chemical Co., Ltd.) 85 parts of methyl ethyl ketone 38 parts of the solution dissolved in 25 parts of methyl ethyl ketone was mixed and dispersed in a sand mill for 2 hours using 1 mmφ glass beads to obtain a dispersion.
As a catalyst, 0.005 part of dioctyltin dilaurate and 40 parts of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) were added to the resulting dispersion to obtain a coating solution for an undercoat layer. This coating solution was applied onto an aluminum substrate having a diameter of 30 mm, a length of 340 mm, and a thickness of 1 mm by a dip coating method, followed by drying and curing at 170 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 19 μm.

(Formation of charge generation layer)
Bragg angles (2θ ± 0.2 °) of X-ray diffraction spectrum using Cukα characteristic X-ray as a charge generating material are at least 7.3 °, 16.0 °, 24.9 °, 28.0 °. A mixture of 15 parts of hydroxygallium phthalocyanine having a diffraction peak, 10 parts of vinyl chloride / vinyl acetate copolymer resin (VMCH, manufactured by Nihon Unicar) as a binder resin, and 200 parts of n-butyl acetate is used as a glass having a diameter of 1 mmφ. The beads were dispersed in a sand mill for 4 hours. To the obtained dispersion, 175 parts of n-butyl acetate and 180 parts of methyl ethyl ketone were added and stirred to obtain a charge generation layer coating solution. This charge generation layer coating solution was dip coated on the undercoat layer and dried at room temperature (25 ° C.) to form a charge generation layer having a thickness of 0.2 μm.

(Formation of charge transport layer)
N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1 ′] biphenyl-4,4′-diamine 45 parts and bisphenol Z polycarbonate resin (viscosity average molecular weight: 50,000) 55 Part was added to 800 parts of chlorobenzene and dissolved to obtain a coating solution for charge transport layer. This coating solution was applied onto the charge generation layer and dried at 130 ° C. for 45 minutes to form a charge transport layer having a thickness of 20 μm.

(Formation of protective layer)
The following components were mixed to prepare a preparation liquid (1).
-2 parts of the guanamine resin represented by the above-mentioned "(A) -1"-70 parts of the compound represented by the above-mentioned "I-16" (charge transport material)-3,5-di-t-butyl-4-hydroxy Toluene (BHT, antioxidant) 1.0 part, dodecylbenzenesulfonic acid (King Industries, Inc .: Nacure 5225) 0.15 part, cyclopentanone (other specific solvent) 50 parts, cyclopentanol (lower alcohol solvent) 35 copies

Next, the following components were stirred and mixed for 24 hours while keeping the liquid temperature at 20 ° C., and using a high-pressure homogenizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.) equipped with a through-type chamber having a fine flow path, 500 kgf / Dispersion treatment under pressure up to cm ² was repeated 6 times to obtain a preparation liquid (2).
・ Polytetrafluoroethylene (PTFE, average primary particle size: 0.2 μm) 6 parts ・ Fluorine comb graft polymer (specific oligomer, manufactured by Toagosei Co., Ltd., trade name: GF400) 0.15 parts ・ Cyclopentanone (other specified Solvent) 20 parts ・ Cyclopentanol (lower alcohol solvent) 15 parts

  The said preparation liquid (1) and the preparation liquid (2) were mixed, and the coating liquid for protective layers was obtained. This coating solution is applied onto the charge transport layer by a dip coating method, air-dried at room temperature (25 ° C.) for 30 minutes, and then cured by heat treatment at 150 ° C. for 1 hour to form a protective layer having a thickness of 7 μm. Thus, a photoreceptor of Example 1 was produced.

<Examples 2 to 28>
In Example 1, according to Table 1 or Table 2, the charge transport material and its blending amount, the guanamine compound or melamine compound and its blending amount, the fluororesin particles, the specific oligomer (oligomer containing fluorine atom), the alcohol solvent and its blending amount A photoconductor was prepared by the method described in Example 1, except that the specific solvent and the blending amount thereof were changed.

<Comparative Examples 1 to 3>
In Example 1, a photoconductor was prepared according to the method described in Example 1 except that the alcohol solvent and its blending amount and other specific solvents and its blending amount were changed according to Table 2.

[Image quality evaluation]
The prepared photoreceptor is mounted on an image forming apparatus (DocuCenter Color 400CP, manufactured by Fuji Xerox Co., Ltd.), and an image forming test is performed to output 500,000 10% halftone images continuously in an environment of 30 ° C. and 85%. The following evaluation was performed.

Measurement of increase in residual potential The residual potential on the surface of the photoconductor immediately after printing the first sheet and the residual potential on the surface of the photoconductor immediately after printing the 500,000th sheet were measured, and the increase was calculated from the difference.
The residual potential was measured by placing a surface potential measuring probe at a position after the charge eliminating lamp of the photoconductor in the image forming apparatus and reading the surface potential.

-Measurement of wear film thickness By measuring the initial film thickness of the protective layer and the film thickness of the protective layer after the image formation test of 500,000 sheets, the film thickness worn by the image formation test of 500,000 sheets in the protective layer of the photoconductor Calculated.

-Graininess The graininess of the first image in the image formation test was evaluated according to the following evaluation criteria.
5: Very good (1 dot has a circularity of 80% or more)
4: Good (1 dot has a circularity of 60% or more and less than 80%)
3: Normal (1 dot has a circularity of 40% or more and less than 60%)
2: Poor (1 dot has a circularity of 20% or more and less than 40%)
1: Very bad (1 dot is less than 20% circularity)
The above evaluation results are shown in Tables 3 and 4.

  Further, the residual solvent in the protective layer of the obtained photoreceptor was detected by gas chromatography. For gas chromatography, HP6890 (manufactured by Agilent) and column HP-5MS (manufactured by Agilent) were used at an oven initial temperature of 45 ° C. Tables 3 and 4 show the types of the residual solvents.

In addition, the specific oligomers described in Table 1 and Table 2 respectively represent the following.
・ GF400 (specific oligomer, manufactured by Toagosei Co., Ltd., molecular weight 120,000)
・ Furgent 750FL (specific oligomer, manufactured by Neos, molecular weight 4000)
・ Surflon S651 (specific oligomer, manufactured by AGC Seikekikal, molecular weight 3000)
PF-6520 (specific oligomer, manufactured by Kitamura Chemical Co., Ltd., molecular weight 5000)
In addition, the description of “%” in the “content” column of the “charge transporting material” and “guanamine compound, melamine compound” described in Table 1 and Table 2 represents the ratio to the total solid content of the protective layer. .

DESCRIPTION OF SYMBOLS 1 Substrate, 2 Photosensitive layer, 2A Charge generation layer, 2B Charge transport layer, 2C Protective layer, 4 Undercoat layer, 7 Electrophotographic photoreceptor, 8 Charging device, 9 Exposure device, 11 Developing device, 13 Cleaning device, 14 Lubrication 40, transfer device, 50 intermediate transfer member, 100 image forming device, 120 image forming device, 131 cleaning blade, 132 fibrous member (roll shape), 133 fibrous member (flat brush shape), 300 process cartridge

Claims (4)

A conductive substrate, and a photosensitive layer on the conductive substrate;
The layer constituting the outermost surface of the photosensitive layer is at least one selected from guanamine compounds and melamine compounds, and at least one selected from —OH, —OCH ₃ , —NH ₂ , —SH and —COOH. Cross-linked product of charge transporting material having one substituent, fluorine resin particles, oligomer containing fluorine atom, lower alcohol solvent having 6 or less carbon atoms, ketone solvent, ether solvent, ester solvent and carbonization And at least one solvent selected from hydrogen-based solvents,
An electrophotographic photosensitive member, wherein a content of the charge transporting material in a layer constituting the outermost surface is 85% by mass or more. The lower alcohol solvent having 6 or less carbon atoms is at least one selected from cyclopentanol, methanol, ethanol, i-propanol, 2-butanol, and n-pentanol;
At least one solvent selected from the ketone solvents, ether solvents, ester solvents and hydrocarbon solvents is cyclopentanone, butyl acetate, isobutyl acetate, methyl ethyl ketone, methyl isobutyl ketone, toluene, ethylbenzene, tetrahydrofuran, The electrophotographic photosensitive member according to claim 1, which is at least one selected from 2-methyltetrahydrofuran and 2-methyltetrahydrofuran. An electrophotographic photoreceptor according to claim 1;
A charging device for charging the surface of the electrophotographic photosensitive member;
An electrostatic latent image forming apparatus for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member;
A developing device for developing the electrostatic latent image with a developer to form a toner image;
A transfer device for transferring the toner image to a transfer medium;
An image forming apparatus comprising:   A process cartridge comprising at least the electrophotographic photosensitive member according to claim 1 and detachable from an image forming apparatus.