JP2010181540A - Electrophotographic photoreceptor, process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor capable of obtaining an image over a long term, the image having a surface hardly scratched and prevented from lowering resistance, thereby preventing the occurrence of density unevenness and image defects. <P>SOLUTION: The electrophotographic photoreceptor has a conductive base body and a photosensitive layer provided on the surface of the conductive base body. The outermost surface layer of the photosensitive layer is structured so as to include a crosslinked material using at least one selected from a guanamine compound and a melamine compound and at least one charge transport material having at least two substituents selected from -OH, -OCH<SB>3</SB>, -NH<SB>2</SB>, -SH and -COOH and the content of the charge transport material is ≥90 mass% to ≤99 mass% and the relation between the composition ratio A (atm%) of oxygen on the surface and the composition ratio B (atm%) of oxygen in a depth 20 nm from the surface measured by an X-ray photoelectric spectroscopy satisfies formula (1): B×2<A<B×4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  An electrophotographic image forming apparatus generally has the following configuration and process. That is, the surface of the electrophotographic photosensitive member is charged to a predetermined polarity and potential by a charging unit, and the surface of the electrophotographic photosensitive member after charging is selectively discharged by image exposure to form an electrostatic latent image. The latent image is developed as a toner image by attaching toner to the electrostatic latent image by the developing unit, and the toner image is transferred to a transfer medium by the transfer unit, and discharged as an image formed product.

  In recent years, electrophotographic photoreceptors have the advantage of being able to obtain high speed and high print quality, and thus have been remarkably used in fields such as copying machines and laser beam printers. As an electrophotographic photosensitive member used in these image forming apparatuses, it is inexpensive, manufacturable and disposable compared to conventional electrophotographic photosensitive members using inorganic photoconductive materials such as selenium, selenium-tellurium alloy, selenium-arsenic alloy, cadmium sulfide. Organic photoreceptors using organic photoconductive materials that have advantages in terms of the point have come to dominate.

On the other hand, it has been proposed to provide a protective layer as a surface layer of the electrophotographic photosensitive member. As a material system for forming the protective layer, for example, a material in which conductive powder is dispersed in a phenol resin (for example, see Patent Document 1) and a material using a chain polymerizable material (for example, see Patent Document 2) have been proposed. Yes. In addition, an image forming apparatus using a photoreceptor in which a charge transport material is contained in a protective layer has been proposed (see, for example, Patent Document 3). Further, there have been proposed a photoreceptor in which an antioxidant is contained in a photosensitive layer (for example, see Patent Document 4) and a photoreceptor in which an oxygen gas permeability coefficient of a surface layer is specified (for example, see Patent Document 5).
Japanese Patent No. 3287678 JP 2005-234546 A JP 2006-85033 A JP-A-6-332216 Japanese Patent No. 3939775

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor in which an image in which occurrence of density unevenness and image defects is suppressed can be obtained over a long period of time by preventing scratches on the surface and suppressing a decrease in resistance. To do.

The above problem is solved by the following means. That is,
The invention according to claim 1
A conductive substrate;
A photosensitive layer provided on the surface of the conductive substrate;
Have
The outermost surface layer of the photosensitive layer has at least one selected from guanamine compounds and melamine compounds and at least two substituents selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. A cross-linked product using at least one kind of charge transporting material possessed, the content of the charge transporting material is 90% by mass or more and 99% by mass or less, and was measured by X-ray photoelectron spectroscopy. An electrophotographic photosensitive member characterized in that a composition ratio A (atm%) of oxygen at the surface and a composition ratio B (atm%) of oxygen at a depth of 20 nm from the surface satisfy the relationship of the following formula (1): is there.
Formula (1)
B × 2 <A <B × 4

The invention according to claim 2
An electrophotographic photoreceptor according to claim 1;
Charging means for charging the electrophotographic photosensitive member, developing means for developing the electrostatic latent image formed on the electrophotographic photosensitive member with toner to form a toner image, and remaining on the surface of the electrophotographic photosensitive member At least one selected from the group consisting of toner removing means for removing toner.

The invention according to claim 3
An electrophotographic photoreceptor according to claim 1;
Charging means for charging the electrophotographic photoreceptor;
Electrostatic latent image forming means for forming an electrostatic latent image on the charged electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image formed on the electrophotographic photosensitive member with toner to form a toner image;
Transfer means for transferring the toner image to a transfer object;
Toner removing means for removing toner remaining on the surface of the electrophotographic photosensitive member;
An image forming apparatus comprising:

According to the first aspect of the present invention, compared to the case where the oxygen ratio on the surface is not controlled, the surface is less likely to be scratched, and the decrease in resistance is suppressed, thereby suppressing the occurrence of density unevenness and image defects. An electrophotographic photosensitive member capable of obtaining a long image can be provided.
According to the second aspect of the present invention, an image in which the occurrence of density unevenness and image defects is suppressed can be obtained over a long period of time as compared with the case where no photoconductor whose surface oxygen ratio is controlled is provided.
According to the third aspect of the present invention, an image in which the occurrence of density unevenness and image defects is suppressed can be obtained over a long period of time as compared with the case where no photoconductor whose surface oxygen ratio is controlled is provided.

(Electrophotographic photoreceptor)
The electrophotographic photosensitive member according to the present embodiment (hereinafter sometimes referred to as “photosensitive member according to the present embodiment”) includes a conductive substrate and a photosensitive layer provided on the surface of the conductive substrate. The outermost surface layer of the photosensitive layer has at least one selected from guanamine compounds and melamine compounds and at least two substituents selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. A cross-linked product using at least one kind of charge transporting material possessed, the content of the charge transporting material is 90% by mass or more and 99% by mass or less, and was measured by X-ray photoelectron spectroscopy. The oxygen composition ratio A (atm%) on the surface and the oxygen composition ratio B (atm%) at a depth of 20 nm from the surface satisfy the relationship of the following formula (1).
Formula (1)
B × 2 <A <B × 4

In the electrophotographic photoreceptor according to the exemplary embodiment, the above-described configuration allows selection from a guanamine compound, a melamine compound, and a specific functional group (—OH, —OCH ₃ , —NH ₂ , —SH, and —COOH). The cross-linking site (cross-linking site) can be polyfunctionalized and highly cross-linked by a charge transporting material having a plurality of substituents (hereinafter referred to as “specific charge transporting material”). As the strength increases, the amount of the charge transporting material increases as compared with the conventional outermost surface layer, and the electric characteristics (sensitivity) are kept good while maintaining this highly crosslinked state.
Further, by controlling the amount of oxygen on the very outermost surface layer, even when the outermost surface layer contains a large amount of charge transporting material, the occurrence of image quality defects due to highly oxidizing gas is suppressed. The reason for this is not clear, but is considered as follows. Highly oxidizing gas does not generate oxide when it comes into contact with charge transporting material, but only draws out electrons and degrades (lowers resistance) charge transporting material. By containing oxygen, an oxide is formed and stabilized (slightly increased in resistance). For this reason, even if a highly oxidizing gas subsequently contacts, electrons are not easily extracted, and the occurrence of image quality defects is suppressed.
Therefore, the electrophotographic photosensitive member according to this embodiment is presumed to have the above effect.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

(Electrophotographic photoreceptor)
Hereinafter, the electrophotographic photosensitive member according to the exemplary embodiment will be described.
FIG. 1 is a schematic cross-sectional view showing an example of an electrophotographic photoreceptor according to this embodiment. 2 and 3 are schematic cross-sectional views showing other examples of the electrophotographic photoreceptor according to this embodiment.

  The electrophotographic photoreceptor 7 shown in FIG. 1 is provided with a subbing layer 1 on a conductive substrate 4, and a photosensitive layer in which a charge generation layer 2, a charge transport layer 3, and a protective layer 5 are sequentially formed thereon. It has been.

  The electrophotographic photosensitive member 7 shown in FIG. 2 includes a photosensitive layer in which the functions are separated into the charge generation layer 2 and the charge transport layer 3 as in the electrophotographic photosensitive member 7 shown in FIG. The electrophotographic photoreceptor 7 shown in FIG. 3 contains the charge generation material and the charge transport material in the same layer (single-layer type photosensitive layer 6 (charge generation / charge transport layer)).

  In the electrophotographic photosensitive member 7 shown in FIG. 2, an undercoat layer 1 is provided on a conductive substrate 4, and a photosensitive layer in which a charge transport layer 3, a charge generation layer 2, and a protective layer 5 are sequentially formed thereon. Is provided. In the electrophotographic photoreceptor 7 shown in FIG. 3, the undercoat layer 1 is provided on the conductive substrate 4, and the photosensitive layer in which the single-layer type photosensitive layer 6 and the protective layer 5 are sequentially formed thereon is provided. It has been.

  In the electrophotographic photoreceptor 7 shown in FIGS. 1, 2 and 3, the protective layer 5 corresponds to the outermost surface layer in the present embodiment. In the electrophotographic photosensitive member shown in FIGS. 1, 2, and 3, the undercoat layer may or may not be provided.

  Hereinafter, each element will be described based on the electrophotographic photoreceptor 7 shown in FIG. 1 as a representative example.

<Conductive substrate>
Examples of the conductive substrate 4 include a metal plate, a metal drum, and a metal belt formed using a metal or an alloy such as aluminum, copper, zinc, stainless steel, chromium, nickel, molybdenum, vanadium, indium, gold, or platinum. Alternatively, a paper, a plastic film, a belt, or the like on which a conductive compound such as a conductive polymer or indium oxide, or a metal or alloy such as aluminum, palladium, or gold is applied, vapor-deposited, or laminated can be given. Here, “conductive” means that the volume resistivity is less than 10 ¹³ Ωcm. In addition, the volume resistivity in this specification is a volume resistivity in 25 degreeC.

  When the electrophotographic photoreceptor 7 is used in a laser printer, the surface of the conductive substrate 4 has a center line average roughness Ra of 0.04 μm or more and 0 in order to prevent interference fringes generated when laser light is irradiated. It is desirable to roughen the surface to 5 μm or less. If Ra is less than 0.04 [mu] m, the effect of preventing interference may be insufficient because it is close to a mirror surface, and if Ra exceeds 0.5 [mu] m, the image quality may be rough even if a film is formed. When non-interfering light is used for the light source, it is not particularly necessary to roughen the interference fringes, and it is possible to prevent the occurrence of defects due to the irregularities on the surface of the conductive substrate 4, and thus it is suitable for longer life.

  Surface roughening methods include wet honing by suspending the abrasive in water and spraying it on the support, or centerless grinding and anodic oxidation in which the support is pressed against a rotating grindstone and continuously ground. Processing is desirable.

  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, the porous anodic oxide film formed by anodic oxidation is chemically active as it is, easily contaminated, and has a large resistance fluctuation due to the environment. Therefore, the pores of the anodic oxide film are sealed with pressurized water vapor or boiling water (a metal salt such as nickel may be added) by volume expansion due to a hydration reaction, and a sealing process is performed to change to a more stable hydrated oxide. It is desirable.

  The thickness of the anodic oxide film is desirably 0.3 μm or more and 15 μm or less. If the film thickness is less than 0.3 μm, the barrier property against implantation may be poor and the effect may be insufficient. On the other hand, if it exceeds 15 μm, the residual potential may increase due to repeated use.

  The conductive substrate 4 may be treated with an acidic aqueous solution containing phosphoric acid, chromic acid and hydrofluoric acid, or boehmite treatment. The treatment with an acidic treatment liquid 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 0.00%. The range of 5% by mass or more and 2% by mass or less is desirable, and the concentration of these acids as a whole is desirably 13.5% by mass or more and 18% by mass or less. The treatment temperature is preferably 42 ° C. or more and 48 ° C. or less, but by keeping the treatment temperature high, a thicker film can be formed faster than when the treatment temperature is lower than the range. The film thickness is preferably from 0.3 μm to 15 μm. If it is less than 0.3 μm, the barrier property against injection may be poor and the effect may be insufficient. On the other hand, if the thickness exceeds 15 μm, the residual potential may increase due to repeated use.

  The boehmite treatment may be performed by immersing in pure water at 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 at 90 ° C. or more and 120 ° C. or less for 5 minutes or more and 60 minutes or less. desirable. 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.

<Underlayer>
The undercoat layer 1 is configured by containing inorganic particles in a 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. This is because it is desirable that the undercoat layer 1 has an appropriate resistance for leak resistance and carrier block property acquisition. If the powder resistance of the inorganic particles is lower than 10 ² Ω · cm, sufficient leakage resistance may not be obtained. If the powder resistance is higher than 10 ¹¹ Ω · cm, the residual potential may be increased. There is.

  As the inorganic particles having the resistance value, it is desirable to use inorganic particles (conductive metal oxide) such as tin oxide, titanium oxide, zinc oxide, and zirconium oxide, and zinc oxide is particularly desirable.

  Further, the inorganic particles may be subjected to a surface treatment, or may be used by mixing two or more kinds 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. Those having a specific surface area of less than 10 m ² / g are liable to cause a decrease in chargeability, and it may be difficult to obtain good electrophotographic characteristics.

  Further, by incorporating inorganic particles and an acceptor compound, a product having excellent electrical properties for a long period of time and carrier blockability can be obtained. As the acceptor compound, any compound can be used as long as the desired characteristics can be obtained. However, quinone compounds such as chloranil and bromoanil, tetracyanoquinodimethane compounds, 2,4,7-trinitrofluorenone, Fluorenone compounds such as 2,4,5,7-tetranitro-9-fluorenone, 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole, and 2,5 Oxadiazole compounds such as -bis (4-naphthyl) -1,3,4-oxadiazole, 2,5-bis (4-diethylaminophenyl) 1,3,4-oxadiazole, xanthone compounds, Desirable are electron transport materials such as thiophene compounds and diphenoquinone compounds such as 3,3 ′, 5,5′tetra-t-butyldiphenoquinone. In particular compounds having an anthraquinone structure are preferable. 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 as long as the desired properties are obtained, but may be contained in the range of 0.01% by mass to 20% by mass with respect to the inorganic particles. desirable. Furthermore, from the viewpoint of preventing charge accumulation and preventing aggregation of inorganic particles, it is desirable to contain in the range of 0.05 mass% to 10 mass%. Aggregation of the inorganic particles tends to cause variations in the formation of the conductive path, which not only tends to cause deterioration in sustainability such as an increase in residual potential during repeated use, but may cause image quality defects such as black spots.

  The acceptor compound may be added only when the undercoat layer 1 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, dispersion is caused by dropping an acceptor compound dissolved in an organic solvent directly or with dry air or nitrogen gas while stirring inorganic particles with a mixer having a large shearing force. Processed without occurring. The addition or spraying is preferably performed at a temperature below the boiling point of the solvent. When spraying at a temperature equal to or higher than the boiling point of the solvent, the solvent evaporates before stirring without causing variation, and the acceptor compound is locally concentrated, making it difficult to perform processing without variation. After addition or spraying, baking may be performed at 100 ° C. or higher. Baking is carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained.

  As a wet method, the inorganic particles are dispersed in a solvent using stirring, ultrasonic waves, a sand mill, an attritor, a ball mill, etc., added with an acceptor compound, stirred or dispersed, and then the solvent is removed without causing variations. It is processed. The solvent removal method is distilled off by filtration or distillation. After removing the solvent, baking may be performed at 100 ° C. or higher. Baking is carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained. In the wet method, water containing inorganic particles can also 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 not particularly limited as long as it has desired characteristics and 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, silane coupling agents are desirably used because they provide good electrophotographic properties. Further, a silane coupling agent having an amino group is desirably used because it gives the undercoat layer 1 good blocking properties.

  Any silane coupling agent having an amino group may be used as long as the desired electrophotographic photoreceptor characteristics can be obtained. Specific examples include γ-aminopropyltriethoxysilane, N-β-. (Aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, etc. However, it is not limited to these.

  Two or more silane coupling agents may be mixed and used. Examples of the silane coupling agent 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-chloropropyltri Examples include methoxysilane, etc. Not intended to be constant.

  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 surface treatment by acceptor provision and a coupling agent etc. simultaneously.

  The amount of the silane coupling agent relative to the inorganic particles in the undercoat layer 1 is arbitrarily set as long as the desired electrophotographic characteristics can be obtained, but from the viewpoint of improving dispersibility, 0.5 mass with respect to the inorganic particles. % To 10% by mass is desirable.

  As the binder resin contained in the undercoat layer 1, any known resin can be used as long as it can form a good film and can obtain desired characteristics. For example, polyvinyl butyral, etc. Acetal resin, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, Known polymer resin compounds such as silicone resins, silicone-alkyd resins, phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, charge transport resins having charge transport groups, and conductive resins such as polyaniline, etc. 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.

  The ratio of the metal oxide to which the acceptor property is imparted in the coating solution for forming the undercoat layer and the binder resin, or the inorganic particles and the binder resin is arbitrarily set within a range in which desired electrophotographic photoreceptor characteristics can be obtained.

  Various additives may be used in the undercoat layer 1 in order to improve electrical characteristics, environmental stability, and image quality. 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, Examples thereof include titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.

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 arbitrarily selected from known organic solvents such as alcohols, aromatics, halogenated hydrocarbons, ketones, ketone alcohols, ethers, esters, etc. Selected. 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 vibration ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker can be used. Further, as the coating method used when the undercoat layer 1 is provided, conventional methods such as blade coating method, wire bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating method, etc. Is used.
The undercoat layer 1 is formed on the conductive substrate 4 using the undercoat layer-forming coating solution thus obtained.

The undercoat layer 1 preferably has a Vickers hardness of 35 or more.
Furthermore, the undercoat layer 1 is set to any thickness as long as desired characteristics can be obtained. The thickness is preferably 15 μm or more, and more preferably 15 μm or more and 50 μm or less.

  When the thickness of the undercoat layer 1 is less than 15 μm, sufficient leakage resistance cannot be obtained, and when it is 50 μm or more, residual potential tends to remain when used for a long period of time, so that it tends to cause an abnormal image density. There are drawbacks.

  Further, the surface roughness (ten-point average roughness) of the undercoat layer 1 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.

Further, the undercoat layer may be polished for adjusting the surface roughness. As a polishing method, buffing, sandblasting, wet honing, grinding, or the like can be used.
The applied 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 2 is a layer containing 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 metal-free phthalocyanine pigments are desirable for near-infrared laser exposure. In particular, hydroxygallium phthalocyanine disclosed in JP-A-5-263007, JP-A-5-279591, and the like. 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, etc. The disclosed titanyl phthalocyanine is more desirable. For near-ultraviolet laser exposure, condensed aromatic pigments such as dibromoanthanthrone, thioindigo pigments, porphyrazine compounds, zinc oxide, and trigonal selenium are more desirable.

The binder resin used for the charge generation layer 2 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 singly 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 2 is formed using a coating solution in which the charge generation material and the binder resin are dispersed in a predetermined 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.

  In addition, 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 can be used. By these dispersion methods, changes in the crystal form of the charge generation material due to dispersion are prevented. 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 2, a usual method such as a blade coating method, a Meyer 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 2 obtained in this way 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 3 is formed containing a charge transport material and a binder resin, or containing a polymer charge transport material.
Examples of 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) shows the ^{(R 13), 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} to an alkoxy group, ^{', R 16,} and ^{R 16'} may be the same or different, each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, 1 to 4 carbon atoms 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 each independently 0 or more and 2 It represents an integer of below.)

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 ═C (R ¹² ) (R ¹³ ) ”and a benzidine derivative having“ —CH═CH—CH═C (R ²⁰ ) (R ²¹ ) ”have charge mobility, protective layer and It is excellent and desirable from the standpoints of adhesiveness and afterimage (hereinafter sometimes referred to as “ghost”) caused by the history of the previous image remaining.

  The binder resin used for the charge transport layer 3 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, polymer charge transport materials such as polyester-based polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 may be used. These binder resins are used singly 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.

  In particular, 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 can be easily obtained. 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, JP-A-8-208820 and the like have a higher charge transportability than other types, and are particularly desirable. is there. The polymer charge transport material can be formed by itself, but may be formed by mixing with a binder resin described later.

  The charge transport layer 3 is formed using 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 linear ethers may be used alone or in combination of two or more. Moreover, a well-known method is used as a dispersion method of each said constituent material.

  The coating method for applying the charge transport layer forming coating solution onto the charge generation layer 2 includes 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 3 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 protective layer 5 is the outermost surface layer in the electrophotographic photosensitive member 7 and is a layer provided in order to give resistance to abrasion and scratches on the outermost surface and to increase toner transfer efficiency.

The protective layer 5 has a charge transport property having at least one selected from a guanamine compound and a melamine compound and a substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. It is comprised including the crosslinked material using the coating liquid containing at least 1 sort (s) of material.

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). The compound represented by the general formula (A) may be used alone or in combination of two or more. In particular, when the compound represented by the general formula (A) is used as a mixture of two or more kinds, or used as a multimer (oligomer) having the structural unit as a structural unit, the solubility in a solvent is improved.

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 the general formula (A), the alkyl group representing 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 or less and 8 or more, and more preferably 1 or more and 6 or less. 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, for example, a known method using guanamine and formaldehyde (for example, Experimental Chemistry Course 4th Edition, Volume 28, page 430).

  Hereinafter, exemplary compounds: (A) -1 to exemplary compounds: (A) -42 are shown as specific examples of the compound represented by the general formula (A), but this embodiment is not limited thereto. The following specific examples are monomers, but multimers (oligomers) having these monomers as structural units may also be used. In the following exemplary compounds, “Me” represents a methyl group, “Bu” represents a butyl group, and “Ph” represents a phenyl group.

  Moreover, as a commercial item of the compound shown by general formula (A), for example, "super becamine (R) L-148-55, super becamine (R) 13-535, super becamine (R) L-- 145-60, Super Becamine (R) TD-126 "manufactured by Dainippon Ink Co., Ltd.," Nicarak BL-60, Nicarak BX-4000 "manufactured by Nippon Carbide Co., 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 particularly preferably at least one of a compound represented by the following general formula (B) and a multimer thereof. Here, the multimer is an oligomer polymerized using the compound represented by the general formula (B) as a structural unit in the same manner as the general formula (A), and the degree of polymerization thereof is, for example, 2 or more and 200 or less (preferably 2 or more). 100 or less). In addition, the compound shown by the general formula (B) or the multimer thereof may be used alone or in combination of two or more. Moreover, you may use together with the compound shown by the said general formula (A), or its multimer. In particular, when the compound represented by the general formula (B) is used as a mixture of two or more kinds or used as a multimer (oligomer) having the same as a structural unit, the solubility in a solvent is improved.

In general formula (B), R ^{6 to} R ¹¹ each independently represent a hydrogen atom, —CH ₂ —OH, —CH ₂ —O—R ¹² , and R ¹² is branched from 1 to 5 carbon atoms. Or a good alkyl group. Examples of the alkyl group include a methyl group, an ethyl group, and a butyl group.

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

  Hereinafter, as specific examples of the compound represented by the general formula (B), exemplary compounds: (B) -1 to exemplary compounds: (B) -7 are shown, but this embodiment is 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 (Nippon Yushi Co., Ltd.), Super Becamine (R) TD-139-60 (Dainippon Ink Co., Ltd.), Uban 2020 (Mitsui Chemicals), Smitex Resin M-3 (Sumitomo Chemical), Nicarak MW-30 (Made by Nippon Carbide).

  In addition, the compound represented by the general formula (B) (including multimers) can be used in an appropriate 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, a specific charge transport material will be described. The specific charge transporting material has at least two (or three) substituents selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. As described above, by having two or more reactive functional groups (substituents) in a specific charge transporting material, the crosslink density is increased and a cross-linked film having higher strength can be obtained, particularly when using a blade cleaner. The rotational torque of the electrophotographic photosensitive member is reduced, and damage to the blade is suppressed and wear of the electrophotographic photosensitive member is suppressed. Although details of this are unknown, since a cured film having a high crosslinking density can be obtained by increasing the number of reactive functional groups, the molecular motion on the extreme surface of the electrophotographic photoreceptor is suppressed, and the surface molecules of the blade member It is presumed that this interaction weakens.

The specific charge transporting material is preferably a compound represented by the following general formula (I).
_{F - ((- R 1 -X} ) n1 R 2 -Y) n2 (I)

In general formula (I), F is an organic group derived from a compound having a hole transporting ability, R ₁ and R ₂ are each independently a linear or branched alkylene group having 1 to 5 carbon atoms. N1 represents 0 or 1, and n2 represents an integer of 2 or more and 4 or less. X represents an oxygen, NH, or sulfur atom, and Y represents —OH, —OCH ₃ , —NH ₂ , —SH, or —COOH.

  In general formula (I), an arylamine derivative is preferably used as the compound having a hole transporting ability in an organic group derived from a compound having a hole transporting ability represented by F. 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). The compound represented by the general formula (II) is particularly excellent in charge mobility, stability against oxidation and the like. Moreover, in General Formula (II), by having 2 or more, preferably 3 or more in the following D in one molecule, a crosslinking density increases and a crosslinked film with higher strength can be obtained.

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 substituted or unsubstituted. D represents — (— R ₁ —X) _n1 R ₂ —Y, c represents 0 or 1 independently, k represents 0 or 1, and the total number of D is 2 or more 4 It is as follows. R ₁ and R ₂ each independently represent a linear or branched alkylene group having 1 to 5 carbon atoms, n1 represents 0 or 1, X represents an oxygen, NH, or sulfur atom. , Y represents —OH, —OCH ₃ , —NH ₂ , —SH, or —COOH.

In the general formula (II), “— (— R ₁ —X) _n1 R ₂ —Y” representing D is the same as in the general formula (I), and R ₁ and R ₂ each independently have 1 or more carbon atoms. 5 or less linear or branched alkylene group. 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), and is preferably 3 or more and 4 or less. That is, in the general formula (I) or general formula (II), when the total number of D is 2 or more and 4 or less, preferably 3 or more and 4 or less in one molecule, the crosslinking density increases and a crosslinked film with higher strength is obtained. In particular, the rotational torque of the electrophotographic photosensitive member when using a blade cleaner is reduced, so that damage to the blade and wear of the electrophotographic photosensitive member are suppressed. Although the details are unknown, increasing the number of reactive functional groups results in a cured film having a high crosslink density, which suppresses molecular motion on the extreme surface of the electrophotographic photosensitive member and interacts with the blade member surface molecules. It is presumed that the action is weakened.

In general formula (II), Ar _{1 to} Ar ₄ are preferably any of the following formulas (1) to (7). Incidentally, the following equation (1) to (7) can be coupled to each Ar ₁ to Ar ₄ - shown with _{"(D) C".}

In the formulas (1) to (7), R ⁹ is phenyl 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 a group selected from the group consisting of a 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, and a carbon number, respectively. One 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 Ar represents a substituted or unsubstituted arylene group, D and c are the same as “D” and “c” in formula (II), s represents 0 or 1, and t represents 1 or more, respectively. Integer less than 3 Represent. ]

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

[In the 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. Represents 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 a predetermined hydrogen atom from the aryl groups of (1) to (7).

  Specific examples of the compound represented by the general formula (I) include the exemplified compounds (I-1) to (I-22) shown below. In addition, the compound shown by the said general formula (I) is not limited at all by these.

  Here, the total content of the guanamine compound (for example, the compound represented by the general formula (A)) and the melamine compound (for example, the compound represented by the general formula (B)) in the protective layer 5 is 0.1% by mass or more. The content is desirably 5% by mass or less, and more desirably 0.5% by mass or more and 2% by mass or less. If the solid content concentration is less than 0.1% by mass, it may be difficult to obtain a dense film, so that sufficient strength may not be obtained. If it exceeds 5% by mass, electrical characteristics and ghost resistance may be deteriorated. is there.

  On the other hand, the solid content concentration in at least one of the coating liquids of the specific charge transporting material is 90% by mass or more and 99% by mass or less, and desirably 94% by mass or more and 99% by mass or less. When this solid content concentration is less than 90% by mass, the electrical characteristics deteriorate. On the other hand, if it exceeds 99% by mass, the content of the guanamine compound and the melamine compound is reduced, and it is difficult to obtain a dense film, so that sufficient strength cannot be obtained.

Further, the protective layer 5 has an oxygen composition ratio A (atm%) on the surface and an oxygen composition ratio B (atm%) at a depth of 20 nm from the surface, as measured by X-ray photoelectron spectroscopy. It satisfies the relationship (1).
Formula (1)
B × 2 <A <B × 4

  Here, the oxygen composition ratios A and B were measured by X-ray photoelectron spectroscopy. In X-ray photoelectron spectroscopy, the elemental composition of the very surface of the measurement surface is measured semi-quantitatively. In the present embodiment, the composition ratio of oxygen on the surface of the protective layer 5 (outermost surface layer) is A (atm%), and is further etched to a depth of 20 nm by C60 ion sputtering. (Atm%). Incidentally, the composition ratio of oxygen is generally constant from the point of being cut by about 10 nm.

As described above, when A is larger than twice the value of B (B × 2), resistance to highly oxidizing gas is improved, and density unevenness associated therewith is suppressed. When the A is not more than twice the value of B (B × 2), high oxidizing gas resistance cannot be obtained. Further, when A is 4 times the value of B (B × 4) or more, density unevenness occurs under high humidity. This is presumably because the adhesion with an ionic substance is increased by a polar group such as -COOH generated by oxidation, and the surface cleaning property is deteriorated.
The A is preferably larger than 2.2 times the B and more preferably 2.4 times. On the other hand, the A is preferably smaller than the value of 3.9 times the B, and more preferably smaller than the value of 3.8 times.

  In view of the effects of the present embodiment, A is preferably 8 atm% or more and 20 atm% or less, more preferably 10 atm% or more and 18 atm% or less. On the other hand, the B is preferably 3 atm% or more and 10 atm% or less, more preferably 4 atm% or more and 8 atm% or less.

As a method of satisfying the relationship of the formula (1), a method of storing the photoconductor in an atmosphere having a high oxygen concentration can be mentioned.
The oxygen concentration in the method of storing the photoreceptor in an atmosphere having a high oxygen concentration is preferably 25% by volume or more and 80% by volume or less, and more preferably 30% by volume or more and 50% by volume or less. The storage time is preferably 3 days or more and 25 days or less, more preferably 7 days or more and 25 days or less. Furthermore, the storage temperature is preferably 20 ° C. or higher and 60 ° C. or lower, and more preferably 30 ° C. or higher and 60 ° C. or lower.

Hereinafter, the protective layer 5 will be described in more detail.
The protective layer 5 includes at least one selected from a guanamine compound (a compound represented by the general formula (A)) and a melamine compound (a compound represented by the general formula (B)) and a specific charge transporting material (general formula). A phenol resin, a melamine resin, a urea resin, an alkyd resin, or the like may be mixed and used together with a crosslinked product with the compound (I). Further, in order to improve the strength, a compound having more functional groups in one molecule such as spiroacetal guanamine resin (for example, “CTU-guanamine” (Ajinomoto Fine Techno Co., Ltd.)) is used as the material in the crosslinked product. Copolymerization is also effective.

  In addition, other heat such as phenol resin, melamine resin, and benzoguanamine resin is added to the protective layer 5 for the purpose of effectively suppressing oxidation by the discharge generated gas by adding so as not to absorb the discharge generated gas excessively. A curable resin may be mixed and used.

  In addition, it is desirable to add a surfactant to the protective layer 5, 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 limitation, those having a plurality of the above structures have high affinity and compatibility with the charge transporting organic compound, and the film forming property of the coating liquid for the protective layer is improved, and wrinkles and unevenness of the protective layer 5 are suppressed. Therefore, it is preferable.

  There are various surfactants having 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 Manufactured). The surfactant having an acrylic structure mainly includes those obtained by polymerizing or copolymerizing monomers such as acrylic or methacrylic compounds.

Specific examples of the surfactant having a perfluoroalkyl group as a fluorine atom include perfluoroalkyl sulfonic acids (for example, perfluorobutane sulfonic acid, perfluorooctane sulfonic acid), and 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 MegaFuck F-114 (manufactured by Dainippon Ink & Chemicals, Inc.), F-top EF-101, EF102, EF-103, EF-104, EF-105, and EF-. 112, 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 perfluoroalkyl carboxylic acids include Megafac F-410 (manufactured by Dainippon Ink & Chemicals, Inc.), Ftop EF-201, EF-204 (and above, manufactured by JEMCO).
As commercial products of perfluoroalkyl group-containing phosphates, MegaFac F-493, F-494 (above, manufactured by Dainippon Ink & Chemicals, Inc.) F-top EF-123A, EF-123B, EF-125M, EF -132 (above, manufactured by JEMCO).

  Examples of the surfactant having an alkylene oxide structure include polyethylene glycol, polyether antifoaming agent, and polyether-modified silicone oil. The polyethylene glycol preferably has a number average molecular weight of 2000 or less, and the 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.

  Furthermore, surfactants having both a fluorine atom and an alkylene oxide structure include those having an alkylene oxide structure or a polyalkylene structure in the side chain, and the end of the alkylene oxide or polyalkylene oxide structure substituted with a substituent containing fluorine. And the like. Specific examples of the surfactant having an alkylene oxide structure include, for example, Megafac F-443, F-444, F-445, and F-446 (above, Dainippon Ink & Chemicals, Inc.), POLY FOX PF636. , PF6320, PF6520, PF656 (above, manufactured by Kitamura Chemical Co., Ltd.).

  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. (above, Big Chemie Ja 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, and 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 7. When the content of the surfactant having a fluorine atom is 0.01% by mass or more, the effect of preventing coating film defects such as suppression of wrinkles and unevenness tends to increase. Further, when the content of the surfactant having a fluorine atom is 1% by mass or less, it becomes difficult to separate the surfactant having the fluorine atom from the cured resin, and the strength of the obtained cured product tends to be maintained. It is in.

  Further, the protective layer 5 may be used in combination with another coupling agent or a fluorine compound for the purpose of adjusting the film formability, flexibility, lubricity, and adhesiveness of the film. 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 addition, (tridecafluoro-1,1,2,2-tetrahydrooctyl) triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, 3- (hepta) for imparting water repellency and the like. 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. If this amount is exceeded, there may be a problem with the film formability of the crosslinked film.

  It is desirable to add an antioxidant to the protective layer 5 for the purpose of preventing deterioration due to an oxidizing gas such as ozone generated in the charging device. When the mechanical strength of the surface of the photoconductor is increased and the photoconductor has a long life, the photoconductor is in contact with the oxidizing gas for a long time, and therefore, stronger oxidation resistance is required than before. 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 5 for the purpose of lowering the residual potential or improving the strength. An example of the particles is silicon-containing particles. The silicon-containing particles are particles containing silicon as a constituent element, and specific examples include colloidal silica and silicone particles. Colloidal silica used as silicon-containing particles is prepared by dispersing silica having an average particle size of 1 nm to 100 nm, preferably 10 nm to 30 nm 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 colloidal silica in the protective layer 5 is not particularly limited, but 0.1% based on the total solid content of the protective layer 5 in terms of film forming properties, electrical characteristics, and strength. It is used in the range of mass% to 50 mass%, desirably 0.1 mass% to 30 mass%.

  The silicone particles used as the silicon-containing particles are selected from silicone resin particles, silicone rubber particles, and silicone surface-treated silica particles, and those commercially available are generally 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 small particles that are chemically inert and excellent in dispersibility in resins, and since the content required to obtain more sufficient properties is low, the crosslinking reaction is not hindered. The surface properties of the photographic photoreceptor are improved. In other words, it is improved in lubricity and water repellency on the surface of the electrophotographic photosensitive member in a state of being taken in without a variation in a strong cross-linked structure, and has good wear resistance and contamination resistance adhesion over a long period of time. Maintained. The content of the silicone particles in the protective layer 5 is desirably 0.1% by mass or more and 30% by mass or less, more desirably 0.5% by mass or more and 10% by mass or less, based on the total amount of the total solid content of the protective layer 5. It is.

Other particles include fluorine-based particles such as ethylene tetrafluoride, ethylene trifluoride, propylene hexafluoride, vinyl fluoride, 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 -TiO ₂ , MgO—Al ₂ O ₃ , FeO—TiO ₂ , TiO ₂ , SnO ₂ , In ₂ O ₃ , ZnO, MgO, etc., semiconductive (volume resistance value is 10 ² Ωcm or more and 10 ¹¹ Ωcm or less) metal An oxide is mentioned. For the same purpose, an 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.

  Further, a metal, metal oxide, carbon black, or the like may be added to the protective layer 5. 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 diameter of the conductive particles is preferably 0.3 μm or less, particularly preferably 0.1 μm or less, from the viewpoint of the transparency of the protective layer.

  In the protective layer 5, a curing catalyst may be used in order to accelerate 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.

  By using a sulfur-containing material as a curing catalyst, the sulfur-containing material exhibits an excellent function as a curing catalyst for a guanamine compound, a melamine compound or a charge transporting material, and a protective layer 5 obtained by accelerating the curing reaction. The mechanical strength of is improved. Furthermore, when the compound represented by the above general formula (I) (including the general formula (II)) is used as the charge transport material, the sulfur-containing material has an excellent function as a dopant for these charge transport materials. The electrical characteristics of the obtained functional layer are further improved. As a result, when an electrophotographic photosensitive member is formed, all of mechanical strength, film formability, and electrical characteristics are achieved at a high level.

  The sulfur-containing material as a curing catalyst is preferably at room temperature (for example, 25 ° C.) or exhibits acidity after heating, and at least one of organic sulfonic acid and its derivatives is most preferable from the viewpoint of adhesiveness, ghost, and electrical characteristics. desirable. The presence of these catalysts in the protective layer 5 is easily confirmed by 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, paratoluenesulfonic acid and dodecylbenzenesulfonic acid are desirable from the viewpoint of catalytic ability and film formability. Further, an organic sulfonate may be used as long as it can be dissociated to some extent in the curable resin composition.

  In addition, by using a so-called thermal latent catalyst that increases the catalytic ability when a temperature above a certain level is applied, the catalytic ability is low at the liquid storage temperature and the catalytic ability is high at the time of curing. And storage stability.

  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 And boron trifluoride monoethylamine complex, boron trifluoride pyridine complex, and the like.

  Among them, a product obtained by blocking a protonic acid and / or a protonic acid derivative with a base in terms of catalytic ability, storage stability, availability, and cost 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 a proton acid derivative, a neutral compound such as an alkali metal salt or alkaline earth metal circle of a proton acid such as sulfonic acid or phosphoric acid, a polymer compound in which a proton acid skeleton is introduced into a polymer chain (polyvinylsulfone) Acid, etc.). Examples of the base that blocks the protonic acid include amines.

  The amines are classified as primary, secondary or tertiary amines. There is no restriction in particular and any of them 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 compounding amount of the catalyst is at least one amount selected from the guanamine compound (the compound represented by the general formula (A)) and the melamine compound (the compound represented by the general formula (B)) (in the coating solution). The solid content concentration is preferably in the range of 0.1% by mass to 50% by mass, and more preferably 10% by mass to 30% by mass. When the amount is less than the above range, the catalytic activity may be too low, and when it exceeds the above range, the light resistance may be deteriorated. The light resistance refers to a phenomenon in which the irradiated portion causes a decrease in density when the photosensitive layer is exposed to light from the outside such as room light. The cause is not clear, but it is presumed that this is because a phenomenon similar to the optical memory effect occurs as disclosed in JP-A-5-099737.

  The protective layer 5 having the above-described configuration is formed using a coating liquid for film formation containing at least one selected from the above guanamine compounds and melamine compounds and at least one of the specific charge transport materials. In the coating liquid for film formation, the constituent components of the protective layer 5 are added as necessary.

  The coating solution for film formation is prepared without a solvent or, if necessary, alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran, diethyl ether and dioxane. You may carry out using solvents, such as. Such solvents can be used singly or in combination of two or more, and preferably have a boiling point of 100 ° C. or lower. As the solvent, it is particularly preferable to use a solvent having at least one hydroxyl group (for example, alcohol).

  The amount of the solvent is arbitrarily set, but if it is too small, the guanamine compound (the compound represented by the general formula (A)) and the melamine compound (the compound represented by the general formula (B)) are likely to be precipitated. 0.5 parts by mass or more and 30 parts by mass or less, preferably 1 part by mass of at least one kind selected from a compound represented by formula (A) and a melamine compound (compound represented by formula (B)) 1 to 20 parts by mass is used.

  In addition, when the coating liquid is obtained by reacting the above components, it may be simply mixed and dissolved, but it is room temperature (for example, 25 ° C.) to 100 ° C., preferably 30 ° C. to 80 ° C. for 10 minutes to 100 Heating may be performed for a period of time or less, preferably 1 hour or more and 50 hours or less. It is also desirable to irradiate ultrasonic waves at this time. Thereby, it is likely that a partial reaction proceeds, and it is easy to obtain a film having no coating film defects and little variation in film thickness.

  Then, a coating solution for forming a film is formed on the charge transport layer 3 by 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. The protective layer 5 can be obtained by curing by applying at a temperature of, for example, 100 ° C. or more and 170 or less if necessary.

  The coating liquid for forming a film is used for, for example, an antistatic film on a fluorescent coloring paint, a glass surface, a plastic surface, etc., in addition to the use as a photoreceptor. When this coating liquid for forming a film is used, a film having excellent adhesion to the lower layer is formed, and performance deterioration due to repeated use over a long period is suppressed.

  Here, the electrophotographic photoreceptor has been described as an example of the function separation type, but the content of the charge generation material in the single-layer type photosensitive layer 6 (charge generation / charge transport layer) is 10% by mass or more and 85% by mass. % Or less, desirably 20 mass% or more and 50 mass% or less. 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 6 (charge generation / charge transport layer) is the same as the method for forming the charge generation layer 2 and the charge transport layer 3. The film thickness of the single-layer type photosensitive layer (charge generation / charge transport layer) 6 is preferably about 5 μm to 50 μm, and more preferably 10 μm to 40 μm.

  In the above description, the outermost surface layer of the photosensitive layer is the protective layer 5, and the protective layer 5 is at least one selected from a guanamine compound and a melamine compound, and a specific charge transporting material (for example, the general formula ( In the case of a layer structure containing a cross-linked product with the compound represented by I) and satisfying the relationship of the formula (1), but in the case of a layer configuration without the protective layer 5, for example, in the outermost surface layer The charge transport layer located contains a cross-linked product of the above structure (at least one selected from guanamine compounds and melamine compounds and a specific charge transport material (compound represented by the general formula (I)), (The relationship of (1) may be satisfied).

(Image forming device / process cartridge)
FIG. 4 is a schematic configuration diagram illustrating the image forming apparatus according to the embodiment. The image forming apparatus 100 is as shown in FIG. A process cartridge 300 including the electrophotographic photosensitive member 7, an exposure device 9, a transfer device 40, and an intermediate transfer member 50 are provided. In the image forming apparatus 100, the exposure device (electrostatic latent image forming unit) 9 is disposed at a position where the electrophotographic photoreceptor 7 can be exposed from the opening of the process cartridge 300, and the transfer device (transfer unit) 40. Is disposed at a position facing the electrophotographic photosensitive member 7 through the intermediate transfer member 50, 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. 4 integrally supports an electrophotographic photosensitive member 7, a charging device 8, a developing device (developing means) 11, and a cleaning device 13 in a housing. The cleaning device (toner removing means) 13 has a cleaning blade (cleaning member), and the cleaning blade 131 is disposed so as to contact the surface of the electrophotographic photosensitive member 7.

  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, a non-contact type roller charger, a known charger such as a scorotron charger using a corona discharge or a corotron charger is preferably used.

  Although not shown, a photosensitive member heating member for increasing the temperature of the electrophotographic photosensitive member 7 and reducing the relative temperature is provided around the electrophotographic photosensitive member 7 for the purpose of improving the stability of the image. Also good.

  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 present invention is not limited to this wavelength, and an oscillation wavelength laser in the 600 nm range or a laser having an oscillation wavelength in the vicinity of 400 nm to 450 nm as a blue laser may be used. For color image formation, a surface-emitting laser light source capable of multi-beam output is also effective.

  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 a two-component developer into contact or non-contact 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 attaching 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 the present embodiment has an average shape factor (shape factor: (ML ² / A) × (π / 4) × 100) from the viewpoint of obtaining high developability and transferability and high image quality. Average, where ML represents the maximum length of the particle, and A represents the projected area of the particle) is preferably 100 or more and 150 or less, more preferably 105 or more and 145 or less, and 110 or more and 140 or less. More desirable. Further, the toner preferably has a volume average particle diameter of 3 μm or more and 12 μm or less, more preferably 3.5 μm or more and 10 μm or less, and further preferably 4 μm or more and 9 μm or less. By using a toner that satisfies this average shape factor and volume average particle diameter, the developability and transferability are improved, and a so-called high-quality image called photographic image quality is obtained.

  The toner is not particularly limited by the production method as long as it satisfies the above average shape factor and volume average particle diameter. For example, the toner may include a binder resin, a colorant, a release agent, and the like. A kneading and pulverizing method in which a charge control agent is added, kneading, pulverizing, and classifying; a method in which the shape of particles obtained by the kneading and pulverizing method is changed by mechanical impact force or thermal energy; Emulsion polymerization of the body, and the resulting dispersion is mixed with a dispersion of a colorant, a release agent and, if necessary, a charge control agent, and then agglomerated and heat-fused to obtain toner particles. Suspension polymerization method in which a polymerizable monomer for obtaining a binder resin, a colorant, a release agent, and a charge control agent, if necessary, are suspended in an aqueous solvent and polymerized; A water-based solution of a resin, a colorant, a release agent, and a solution such as a charge control agent as necessary. Toner is used which is suspended in and produced by a dissolution suspension method in which granulated.

  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 heat-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 are composed of a binder resin, a colorant, and a release agent, and include silica and a charge control agent as necessary.

  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, and 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 representative example.

  Typical examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, Fischer tropical 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 the toner is manufactured by a wet manufacturing method, it is desirable to use a material that is difficult to dissolve in water in terms of controlling ionic strength and reducing wastewater contamination. The toner may be either a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material.

  As the toner used in the developing device 11, the toner base particles and the external additive are mixed with a Henschel mixer or a V blender.

Manufactured by mixing. In addition, when the toner base particles are produced by a wet method, external addition can also be performed 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, mineral 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, and the like may be added for the purpose of removing deposits and deteriorated materials on the surface of the electrophotographic photosensitive member. .

  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 5 nm to 1000 nm, more preferably 5 nm to 800 nm, and even more preferably 5 nm to 700 nm in terms of number average particle diameter. If the average particle size is less than the lower limit, the polishing ability may be insufficient. On the other hand, if the average particle size exceeds the upper limit, the surface of the electrophotographic photosensitive member may be easily damaged. 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.

  Other inorganic oxides added to the toner are small-diameter inorganic oxides with a primary particle size of 40 nm or less for powder flowability, charge control, etc. It is desirable to add a larger diameter inorganic oxide. Known inorganic oxide particles are used, but it is desirable to use silica and titanium oxide in combination for precise charge control.

Further, the surface treatment of the small-diameter inorganic particles increases the dispersibility and increases the effect of increasing the powder fluidity. Furthermore, it is desirable to add carbonates such as calcium carbonate and magnesium carbonate and inorganic minerals such as hydrotalcite in order to remove the discharge purified product.

  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 the transfer device 40, for example, a contact transfer charger using a belt, a roller, a film, a rubber blade, etc., a known transfer charger such as a scorotron transfer charger using a corona discharge or a corotron transfer charger is used. 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 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. 5 is a schematic cross-sectional view showing an image forming apparatus according to another embodiment. As shown in FIG. 5, the image forming apparatus 120 is a tandem-type full-color 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 one color. The image forming apparatus 120 has the same configuration as that of the image forming apparatus 100 except that it is a tandem system.

  When the electrophotographic photosensitive member of the present invention is used in a tandem type image forming apparatus, the electric characteristics of the four photosensitive members are stabilized, so that an image quality with excellent color balance can be obtained over a longer period.

Further, in the image forming apparatus (process cartridge) according to the present embodiment, the developing device (developing means) is a developer holder that moves (rotates) in the opposite direction to the moving direction (rotating direction) of the electrophotographic photosensitive member. It is desirable to have a developing roller that is Here, the developing roller has a cylindrical developing sleeve that holds developer on the surface, and the developing device has a configuration that includes a regulating member that regulates the amount of developer supplied to the developing sleeve. Can be mentioned. By moving (rotating) the developing roller of the developing device in a direction opposite to the rotation direction of the electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is rubbed with toner remaining between the developing roller and the electrophotographic photosensitive member. The And this rubbing, at least one selected from a guanamine compound (compound represented by the general formula (A)) and a melamine compound (compound represented by the general formula (B)) and a specific charge transporting material (particularly The discharge product adhered to the surface of the electrophotographic photosensitive member due to the deposit removability enhanced by the cross-linked product with the material that increases the number of reactive functional groups to obtain a cured film having a high cross-linking density as described above. In particular, it is considered that the scraping property of the low-resistance substance due to ozone and NOx is improved, and the accumulation of such discharge products is suppressed for a very long time. As a result, the occurrence of image quality defects peculiar to a high wear resistance photoconductor such as resolution reduction, streaks, and image blurring is suppressed, and it is assumed that higher image quality and longer life have been achieved at a higher level. Moreover, it is considered that excellent slipperiness of the electrophotographic photosensitive member surface is maintained over a long period of time by suppressing the accumulation of discharge products. As a result, the cleaning blade can be prevented from turning over or generating abnormal noise, and a high level of cleaning performance can be maintained for a long time.
In the image forming apparatus of the present embodiment, the distance between the developing sleeve and the photosensitive member is preferably 200 μm or more and 600 μm or less, and more preferably 300 μm or more and 500 μm, from the viewpoint of suppressing the accumulation of discharge products over a longer period. The following is more desirable. From the same point of view, the distance between the developing sleeve and the regulating blade, which is a regulating member that regulates the developer amount, is desirably 300 μm or more and 1000 μm or less, and more desirably 400 μm or more and 750 μm or less.
Further, from the viewpoint of suppressing the accumulation of discharge products over a longer period, the absolute value of the moving speed of the developing roll surface is 1.5 times or more the absolute value (process speed) of the moving speed of the photoreceptor surface. Desirably, it is 5 times or less, and more desirably 1.7 times or more and 2.0 times or less.

  Further, in the image forming apparatus (process cartridge) according to the present embodiment, the developing device (developing unit) includes a developer holding body having a magnetic material, and is a two-component developer containing a magnetic carrier and toner. It is desirable to develop an image. In this configuration, a clearer image quality can be obtained with a color image, and higher image quality and longer life can be achieved compared to the case of a one-component developer, particularly a non-magnetic one-component developer.

    Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

<Example 1>
(Preparation of undercoat layer)
Zinc oxide: (average particle size 70 nm: manufactured by Teica Co., Ltd .: specific surface area value 15 m ² / g) 100 parts by mass is stirred and mixed with 500 parts by mass of tetrahydrofuran, and silane coupling agent (KBM503: manufactured by Shin-Etsu Chemical Co., Ltd.) 1.3 parts by mass Part was added and stirred 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 by mass of the surface-treated zinc oxide was stirred and mixed with 500 parts by mass of tetrahydrofuran, a solution prepared by dissolving 0.6 parts by mass of alizarin in 50 parts by mass of tetrahydrofuran was added, and the mixture was stirred at 50 ° C. for 5 hours. did. 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 by mass of this alizarin-provided zinc oxide and a curing agent (blocked isocyanate Sumijoule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.): 13.5 parts by mass and 15 parts by mass of butyral resin (ESREC BM-1, manufactured by Sekisui Chemical Co., Ltd.) 38 parts by mass of the solution dissolved in 85 parts by mass and 25 parts by mass of methyl ethyl ketone were mixed, and dispersion was performed for 2 hours with a sand mill using 1 mmφ glass beads.
Dioctyltin dilaurate: 0.005 parts by mass and silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone): 40 parts by mass were added as catalysts to the resulting dispersion to obtain an undercoat layer coating solution. This coating solution was applied on an aluminum substrate having a diameter of 60 mm, a length of 357 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.

(Preparation 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 consisting of 15 parts by mass of hydroxygallium phthalocyanine having a diffraction peak, 10 parts by mass of vinyl chloride / vinyl acetate copolymer resin (VMCH, manufactured by Nihon Unicar) as a binder resin, and 200 parts by mass of n-butyl acetate, The glass beads having a diameter of 1 mmφ were dispersed for 4 hours by a sand mill. To the obtained dispersion, 175 parts by mass of n-butyl acetate and 180 parts by mass of methyl ethyl ketone were added and stirred to obtain a coating solution for a charge generation layer. 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.

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

(Preparation of protective layer)
Guanamine resin (previously exemplified compound: (A) -14): 5 parts by mass, compound represented by general formula (I) as charge transport material (previously exemplified compound: (I-1)): 92 parts by mass, oxidized As an inhibitor, 3,5-di-t-butyl-4-hydroxytoluene (BHT): 4.4 parts by mass, dodecylbenzenesulfonic acid: 0.5 parts by mass, leveling agent BYK-302 (BIC Chemie Japan Co., Ltd.) Manufactured): 0.1 parts by mass and cyclopentanol: 160 parts by mass were added to prepare a coating solution for a protective layer. This coating solution is applied onto the charge transport layer by a dip coating method, air-dried at room temperature for 30 minutes, and then heated and cured at 150 ° C. for 1 hour to form a protective layer having a thickness of about 6 μm. α was produced.

(surface treatment)
The obtained photoreceptor α is inserted and sealed in a container filled with gas having an oxygen concentration of 50% by volume, and the temperature in the container is adjusted to 40 ° C., and the photoreceptor α is kept in this state for 3 days. Stored. The photoconductor obtained by storing for 3 days and surface-treating was designated as photoconductor α1 of Example 1.
The composition ratio A of oxygen on the surface of the photoreceptor α1 and the composition ratio B of oxygen at a depth of 20 nm from the surface were measured by the method described above. As a result, A was 10.6 atm%, B was 4.8 atm%, and the ratio of A to B (A / B) was about 2.2.

<Evaluation>
The obtained photoreceptor α1 was placed at the black position of Docu Center C75550 I manufactured by FUJI XEROX, and A2 size (Fuji Xerox, C2 paper) with a 20% halftone image under high temperature and high humidity (28 ° C., 85%). The following evaluation was carried out on the 5000th image and the first 20% halftone image that was re-output after leaving in the same environment for 12 hours after forming 5000 continuous images. The results are shown in Table 1. The “specific substituent” in “Number of specific substituents in charge transport material” in Table 1 represents a group selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH.

[Density change]
The image density of the first image and the image density of the 5000th image obtained by the continuous image formation were measured with a spectral densitometer (X-Rite 938) and evaluated according to the following criteria.
○: The image density difference ΔD between the first sheet and the 5000th sheet is less than 0.1.
Δ: The image density difference ΔD between the first sheet and the 5000th sheet is 0.1 or more and less than 0.15.
×: The image density difference ΔD between the first sheet and the 5000th sheet is 0.15 or more.

[Image quality defect]
The image quality defect of the 5000th image obtained by the continuous image formation was visually evaluated according to the following criteria.
○: No image quality defect due to scratches or film peeling on the surface of the photoreceptor.
×: Image quality defects due to scratches on the surface of the photoreceptor and film peeling.

[Density unevenness]
The first 20% halftone image re-output after being left for 12 hours was visually evaluated for density unevenness according to the following criteria.
○: No density unevenness in the photoconductor cycle.
Δ: Slight density unevenness in the photoconductor cycle (within image quality tolerance).
X: Clear density unevenness in the photoconductor cycle (outside image quality tolerance).

<Example 2>
In the production of the protective layer in Example 1, the guanamine resin (previously exemplified compound: (A) -14): 5 parts by mass was added to 5 parts by mass of the melamine resin (previously exemplified compound: (B) -2): 5 parts by mass. : (I-1): Photoconductor β was prepared in the same manner as in Example 1 except that 92 parts by mass was changed to 92 parts by mass of the exemplified compound (I-9). Furthermore, the surface treatment similar to that in Example 1 was performed on the photoreceptor β to obtain a photoreceptor β1. The same evaluation as in Example 1 was performed on the photoreceptor β1. The results are shown in Table 1. The oxygen composition ratio A on the surface of the photoreceptor β1 measured by the above-described method is 10.9 atm%, and the oxygen composition ratio B at a depth of 20 nm from the surface is 4.5 atm%. The ratio (A / B) was about 2.4.

<Example 3>
In preparation of the protective layer in Example 2, the usage-amount of a melamine resin (the said exemplary compound: (B) -2) is 1 mass part, and the usage-amount of the said exemplary compound: (I-9) is 99 mass parts, Except for changing the amount of dodecylbenzenesulfonic acid used to 0.1 parts by mass, and further changing 3,5-di-t-butyl-4-hydroxytoluene (BHT): 4.4 parts by mass to 1 part by mass In the same manner as in Example 2, a photoreceptor γ was produced. Further, the photoreceptor γ was subjected to the same surface treatment as in Example 2 to obtain a photoreceptor γ1. Evaluation similar to Example 1 was implemented with respect to the photoreceptor γ1. The results are shown in Table 1. The oxygen composition ratio A measured on the surface of the photoreceptor γ1 was 10.6 atm% and the oxygen composition ratio B at a depth of 20 nm from the surface was 4.6 atm%, which was measured by the method described above. The ratio (A / B) was about 2.3.

<Example 4>
In the surface treatment in Example 3, a photoconductor γ2 was obtained in the same manner as in Example 3 except that the storage period was changed to 10 days. Evaluation similar to Example 1 was implemented with respect to the photoreceptor γ2. The results are shown in Table 1. The oxygen composition ratio A on the surface of the photoreceptor γ2 measured by the above-described method is 17.4 atm%, and the oxygen composition ratio B at a depth of 20 nm from the surface is 4.6 atm%. The ratio (A / B) was about 3.8.

<Comparative Example 1>
A photoreceptor δ was produced in the same manner as in Example 1 except that the guanamine resin was not used in the production of the protective layer in Example 1. Further, the photoreceptor δ was subjected to the same surface treatment as in Example 1 to obtain a photoreceptor δ1. The same evaluation as in Example 1 was performed on the photoreceptor δ1. The results are shown in Table 1. The oxygen composition ratio A measured on the surface of the photoreceptor δ1 was 11.0 atm% and the oxygen composition ratio B at a depth of 20 nm from the surface was 4.5 atm%, which was measured by the method described above. The ratio (A / B) was about 2.4.

<Comparative example 2>
In the production of the protective layer in Example 1, the photoreceptor ε was produced in the same manner as in Example 1 except that 92 parts by mass of the exemplified compound (I-1) was changed to 92 parts by mass of the compound having the following structure. did. Further, the photoreceptor ε was subjected to the same surface treatment as in Example 1 to obtain a photoreceptor ε1. Evaluation similar to Example 1 was implemented with respect to the photoreceptor ε1. The results are shown in Table 1. The oxygen composition ratio A on the surface of the photoreceptor ε1 measured by the method described above was 9.1 atm%, and the oxygen composition ratio B at a depth of 20 nm from the surface was 4.1 atm%. The ratio (A / B) was about 2.2.

<Comparative Example 3>
In the production of the protective layer in Example 1, the amount of the exemplified compound (I-1) used is 88 parts by mass, and the amount of 3,5-di-t-butyl-4-hydroxytoluene (BHT) used is 6. A photoreceptor ζ was produced in the same manner as in Example 1 except that the content was changed to 4 parts by mass. Further, the photoconductor ζ1 was subjected to the same surface treatment as in Example 1 to obtain a photoconductor ζ1. Evaluation similar to Example 1 was implemented with respect to the photoreceptor ζ1. The results are shown in Table 1. The oxygen composition ratio A measured on the surface of the photoreceptor ζ1 was 10.6 atm% and the oxygen composition ratio B at a depth of 20 nm from the surface was 4.9 atm%, which was measured by the method described above. The ratio (A / B) was about 2.2.

<Comparative example 4>
In the surface treatment in Example 1, a photoreceptor α2 was obtained in the same manner as in Example 1 except that the storage period was changed to 1 day. The same evaluation as in Example 1 was performed on the photoreceptor α2. The results are shown in Table 1. The oxygen composition ratio A on the surface of the photoreceptor α2 measured by the above-described method was 8.1 atm%, and the oxygen composition ratio B at a depth of 20 nm from the surface was 4.6 atm%. The ratio (A / B) was about 1.8.

<Comparative Example 5>
In the surface treatment in Example 1, a photoreceptor α3 was obtained in the same manner as in Example 1 except that the storage period was changed to 30 days. The same evaluation as in Example 1 was performed on the photoreceptor α3. The results are shown in Table 1. The oxygen composition ratio A on the surface of the photoreceptor α3 measured by the method described above was 18.9 atm%, and the oxygen composition ratio B at a depth of 20 nm from the surface was 4.6 atm%. The ratio (A / B) was about 4.1.

1 is a schematic partial cross-sectional view showing an electrophotographic photosensitive member according to an embodiment. 1 is a schematic partial cross-sectional view showing an electrophotographic photosensitive member according to an embodiment. 1 is a schematic partial cross-sectional view showing an electrophotographic photosensitive member according to an embodiment. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment. It is a schematic block diagram which shows the image forming apparatus which concerns on other embodiment.

DESCRIPTION OF SYMBOLS 1 Undercoat layer 2 Charge generation layer 3 Charge transport layer 4 Conductive substrate 5 Protective layer 6 Single layer type photosensitive layer 7 Electrophotographic photoreceptor 8 Charging device 9 Exposure device 11 Development device 13 Cleaning device 14 Lubricant 40 Transfer device 50 Intermediate Transfer body 100 Image forming apparatus 120 Image forming apparatus 132 Fibrous member (roll shape)
133 Fibrous member (flat brush shape)

Claims (3)

A conductive substrate;
A photosensitive layer provided on the surface of the conductive substrate;
Have
The outermost surface layer of the photosensitive layer has at least one selected from guanamine compounds and melamine compounds and at least two substituents selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. A cross-linked product using at least one kind of charge transporting material possessed, the content of the charge transporting material is 90% by mass or more and 99% by mass or less, and was measured by X-ray photoelectron spectroscopy. An electrophotographic photosensitive member, wherein the oxygen composition ratio A (atm%) on the surface and the oxygen composition ratio B (atm%) at a depth of 20 nm from the surface satisfy the relationship of the following formula (1): .
Formula (1)
B × 2 <A <B × 4 An electrophotographic photoreceptor according to claim 1;
Charging means for charging the electrophotographic photosensitive member, developing means for developing the electrostatic latent image formed on the electrophotographic photosensitive member with toner to form a toner image, and remaining on the surface of the electrophotographic photosensitive member At least one selected from the group consisting of toner removing means for removing toner. An electrophotographic photoreceptor according to claim 1;
Charging means for charging the electrophotographic photoreceptor;
Electrostatic latent image forming means for forming an electrostatic latent image on the charged electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image formed on the electrophotographic photosensitive member with toner to form a toner image;
Transfer means for transferring the toner image to a transfer object;
Toner removing means for removing toner remaining on the surface of the electrophotographic photosensitive member;
An image forming apparatus comprising: