JP4640070B2 - Electrophotographic photosensitive member, process cartridge, and image forming apparatus - Google Patents

Description

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

  2. Description of the Related Art Conventionally, as an electrophotographic image forming apparatus, an apparatus that sequentially performs processes such as charging, exposure, development, transfer, and cleaning using an electrophotographic photosensitive member (hereinafter sometimes referred to as “photosensitive member”) is widely known. ing. In the field of such image forming apparatuses, recently, there are increasing demands for higher image quality and longer life of the apparatus, and improvement of each member and system is being studied to meet such demands.

  For example, a photoconductor used for image writing is susceptible to stress during charging, cleaning, and the like, and scratches and wear on the surface of the photoconductor may cause image defects. Therefore, a method has been proposed in which a protective layer obtained by crosslinking a phenol resin is provided on the surface of the photoconductor to improve the mechanical strength of the photoconductor (see, for example, Patent Documents 1 and 2).

JP 2002-82469 A JP 2003-186234 A

  However, even if it is possible to suppress the occurrence of scratches and abrasion on the photoreceptor by the above method, the image quality may deteriorate due to the following reasons when the image forming apparatus is used for a long period of time. Longevity and longevity cannot be achieved.

  That is, it is necessary to replace consumables such as process cartridges and toner cartridges during the period of use of the image forming apparatus. Normally, consumables are exchanged by opening the front cover of the apparatus. According to a study, it has been found that density unevenness may occur in an image if a part of the surface of the photoreceptor is exposed to strong light such as a fluorescent lamp during the replacement. In particular, since the photoreceptor having the protective layer is intended for long-term use, the above-described density unevenness tends to occur because the chance of exposure to light increases.

  Providing a protective layer with excellent mechanical strength in the photosensitive layer is expected to be effective in achieving higher image quality and longer life of the image forming apparatus. Actually, sufficient examination has not yet been made on the resistance to exposure (hereinafter sometimes referred to as “light fatigue resistance”).

  The present invention has been made in view of the above circumstances, and an electrophotographic photoreceptor capable of sufficiently suppressing the occurrence of density unevenness even when exposed to light such as a fluorescent lamp, and such an electrophotographic photoreceptor. It is an object of the present invention to provide a process cartridge and an image forming apparatus that can achieve longer life and higher image quality.

In order to achieve the above object, an electrophotographic photosensitive member of the present invention includes a conductive support and a protective layer provided on the conductive support and disposed on the side farthest from the conductive support. An electrophotographic photosensitive member having a photosensitive layer, wherein the volume resistivity per 1 cm ² of the surface of the photosensitive layer measured under an environment of a temperature of 22 ° C. and a humidity of 55% RH is R0 (Ω · cm) and 1000 Lux When the volume resistivity per 1 cm ² of the surface of the photosensitive layer exposed to 10 minutes of white light is R1 (Ω · cm), the following formulas (1) and (2) are satisfied.
3.7 × 10 ¹⁰ Ω · cm ≦ R0 ≦ 8.9 × 10 ¹⁰ Ω · cm (1)
0.1 ≦ (R1 / R0) ≦ 0.71 (2)

  Here, the volume resistivity R0 and R1 is measured by attaching a 1 cm × 1 cm electrode on the surface of the photosensitive layer, under the environment of a temperature of 22 ° C. and a humidity of 55% RH, using a frequency response analyzer at a frequency of 1 Hz. The value obtained is used.

  According to such an electrophotographic photosensitive member, by providing the photosensitive layer satisfying the above formulas (1) and (2), the occurrence of density unevenness can be sufficiently suppressed even when exposed to light such as a fluorescent lamp. Therefore, an image forming apparatus capable of forming a good image quality over a long period can be realized. Further, according to the photoconductor of the present invention, it is possible to maintain the image quality of a halftone image at a high level for a long period of time by preventing density unevenness.

  The reason why the above-described effect is achieved by the present invention is not clear, but the present inventors infer as follows. That is, the density unevenness caused by exposure of the photoconductor to light is caused not only by the sensitivity change of the charge generation material but also by a combination of a plurality of factors such as sensitivity change and chargeability change caused by the protective layer. Conceivable. In contrast, according to the present invention, the cause of density unevenness contained in the entire photosensitive layer can be estimated with high accuracy by using the volume resistivity of the photosensitive layer under specific conditions as an index. It is presumed that a photosensitive layer having excellent properties could be obtained, and that both a long life and high image quality could be achieved.

  In the electrophotographic photoreceptor of the present invention, the photosensitive layer preferably contains hydroxygallium phthalocyanine having a maximum peak wavelength in the range of 810 to 839 nm in the spectral absorption spectrum in the wavelength range of 600 to 900 nm. By blending the above-mentioned hydroxygallium phthalocyanine into the photosensitive layer so as to satisfy the above formulas (1) and (2), the photoreceptor can exhibit excellent electrophotographic characteristics, and further achieve a high level of image quality. Can be achieved.

The hydroxygallium phthalocyanine preferably has an average particle size of 0.2 μm or less, a maximum particle size of 1.2 μm or less, and a BET specific surface area of 45 m ² / g or more. By using such hydroxygallium phthalocyanine, it becomes easier to form a photosensitive layer satisfying the above formulas (1) and (2), and excellent electrophotographic characteristics can be obtained more reliably.

  In the electrophotographic photoreceptor of the present invention, it is preferable that the protective layer contains a phenol resin having a cross-linked structure and charge transportability. Since the photosensitive layer has such a protective layer and satisfies the above formulas (1) and (2), it satisfies all of mechanical strength, electrical characteristics and light fatigue resistance at a higher level. be able to.

  Furthermore, the protective layer further contains an organic sulfonic acid and / or a derivative thereof, and the content of the organic sulfonic acid and / or the derivative thereof is 0.01 to 0.25% by mass based on the total solid content of the protective layer. It is preferable that

  According to the study by the present inventors, by forming a protective layer using an organic sulfonic acid and / or a derivative thereof as a curing catalyst for a phenol resin, the mechanical strength of the protective layer can be further improved and the surface of the photoreceptor It has been found that the residual potential of can be further reduced. However, on the other hand, it has been found that the light fatigue resistance of the photosensitive layer is lowered and the above-described density unevenness is likely to occur. On the other hand, according to the electrophotographic photosensitive member, a photosensitive layer satisfying the above formulas (1) and (2) is formed using the organic sulfonic acid and / or its derivative so as to have the above content. As a result, both reduction of the residual potential of the photosensitive layer and light fatigue resistance can be achieved at a high level.

  In the electrophotographic photosensitive member of the present invention, it is preferable that the protective layer includes a phenol resin including a phenol derivative having a methylol group and a charge transporting substance having a reactive functional group. Thereby, higher image quality and longer life can be achieved at a higher level. The reason why such an effect can be obtained is that when the protective layer is formed using the above-described phenol derivative and the charge transporting substance, the charge transporting substance is chemically bonded in the cross-linked structure of the phenol resin. This is considered to be because both the mechanical strength and electrical characteristics of the protective layer to be formed are further enhanced.

  The charge transporting material preferably has at least one functional group selected from a hydroxyl group, a carboxyl group, an alkoxysilyl group, an epoxy group, a carbonate group, a thiol group, and an amino group.

ここで、式（ＩＶ）中、Ｆは正孔輸送性を有するｎ５価の有機基を、Ｔは２価の基を、Ｙは酸素原子又は硫黄原子を、Ｒ^４、Ｒ^５及びＲ^６はそれぞれ独立に水素原子又は１価の有機基を、Ｒ^７は１価の有機基を、ｍ１は０又は１を、ｎ５は１〜４の整数を、それぞれ示す。但し、Ｒ^６とＲ^７は互いに結合してＹをヘテロ原子とする複素環を形成してもよい。

ここで、式（Ｖ）中、Ｆは正孔輸送性を有するｎ６価の有機基を、Ｔは２価の基を、Ｒ^８は１価の有機基を、ｍ２は０又は１を、ｎ６は１〜４の整数を、それぞれ示す。 Furthermore, the charge transporting substance is preferably a compound represented by the following general formula (I), (II), (III), (IV) or (V).
_{^{F [- (X 1) n}} -R 1 -Z 1 H] m ... (I)
In the formula (I), F represents an organic group derived from a compound having a hole transporting ability, X ¹ represents an oxygen atom or a sulfur atom, R ¹ represents an alkylene group, Z ¹ represents an oxygen atom, sulfur. An atom, NH or COO, n represents 0 or 1, and m represents an integer of 1 to 4.
_{^{F [- (X 2) n1}} - (R 2) n2 - (Z 2) n3 G] n4 ... (II)
In the formula (II), F represents an organic group derived from a compound having a hole transporting ability, X ² represents an oxygen atom or a sulfur atom, R ² represents an alkylene group, Z ² represents an oxygen atom, sulfur. Atom, NH or COO, G represents an epoxy group, n1, n2 and n3 each independently represents 0 or 1, and n4 represents an integer of 1 to 4.
F [—D—Si (R ³ ) _(3-a) Q _a ] _b (III)
Here, in Formula (III), F is an organic group derived from a compound having a hole transporting ability, D is a divalent group having flexibility, R ³ is a hydrogen atom, substituted or unsubstituted An alkyl group or a substituted or unsubstituted aryl group, Q represents a hydrolyzable group, a represents an integer of 1 to 3, and b represents an integer of 1 to 4.

Here, in formula (IV), F is an n5-valent organic group having hole transportability, T is a divalent group, Y is an oxygen atom or a sulfur atom, R ⁴ , R ⁵ and R ⁶ are Each independently represents a hydrogen atom or a monovalent organic group, R ⁷ represents a monovalent organic group, m1 represents 0 or 1, and n5 represents an integer of 1 to 4. However, R ⁶ and R ⁷ may combine with each other to form a heterocycle having Y as a heteroatom.

Here, in the formula (V), F is an n6 valent organic group having a hole transport property, T is a divalent group, R ⁸ is a monovalent organic group, m2 is 0 or 1, n6 Represents an integer of 1 to 4, respectively.

  When the protective layer contains at least one compound of the compounds represented by the general formulas (I) to (V), the mechanical strength and electrical characteristics of the protective layer are further enhanced, and high image quality is achieved. And longer life can be achieved at a higher level.

  The present invention also forms the toner image by developing the electrophotographic photosensitive member of the present invention, a charging means for charging the electrophotographic photosensitive member, and the electrostatic latent image formed on the electrophotographic photosensitive member with toner. There is provided a process cartridge characterized by comprising at least one selected from the group consisting of developing means for cleaning and cleaning means for removing toner remaining on the surface of the electrophotographic photosensitive member.

  The present invention also provides the electrophotographic photoreceptor of the present invention, a charging means for charging the electrophotographic photoreceptor, an exposure means for forming an electrostatic latent image on the charged electrophotographic photoreceptor, An image forming apparatus comprising: developing means for developing a latent image with toner to form a toner image; and transfer means for transferring the toner image from an electrophotographic photosensitive member to a transfer target. To do.

  These process cartridges and image forming apparatuses can form high-quality images over a long period of time by including the electrophotographic photosensitive member of the present invention.

  According to the present invention, an electrophotographic photosensitive member that can sufficiently suppress the occurrence of density unevenness even when exposed to light such as a fluorescent lamp, and the electrophotographic photosensitive member provided with such an electrophotographic photosensitive member have a longer life and higher image quality. It is possible to provide a process cartridge and an image forming apparatus that can achieve the above.

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

(Electrophotographic photoreceptor)
FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of the electrophotographic photosensitive member of the present invention. An electrophotographic photosensitive member 1 shown in FIG. 1 includes a conductive support 2 and a photosensitive layer 3. The photosensitive layer 3 has a structure in which an undercoat layer 4, a charge generation layer 5, a charge transport layer 6 and a protective layer 7 are laminated on the conductive support 2 in this order.

  2 and 3 are schematic sectional views showing other preferred embodiments of the electrophotographic photosensitive member of the present invention. The electrophotographic photosensitive member shown in FIGS. 2 and 3 includes the photosensitive layer 3 in which the functions are separated into the charge generation layer 5 and the charge transport layer 6 as in the electrophotographic photosensitive member shown in FIG.

  The electrophotographic photoreceptor 1 shown in FIG. 2 has a structure in which a charge generation layer 5, a charge transport layer 6 and a protective layer 7 are sequentially laminated on a conductive support 2. The electrophotographic photoreceptor 1 shown in FIG. 3 has a structure in which an undercoat layer 4, a charge transport layer 6, a charge generation layer 5, and a protective layer 7 are sequentially laminated on a conductive support 2.

  As described above, when the photosensitive layer provided in the electrophotographic photosensitive member of the present invention is a function-separated type photosensitive layer, it is possible to achieve a higher function because it is possible to perform functional separation that each layer only has to satisfy each function.

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

  Examples of the conductive support 2 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. Etc. Further, as the conductive support 2, paper, plastic film, belt or the like coated, vapor-deposited or laminated with a conductive polymer, a conductive compound such as indium oxide, or a metal or alloy such as aluminum, palladium, or gold can be used.

  The surface of the conductive support 2 is preferably roughened to a center line average roughness Ra of 0.04 μm to 0.5 μm in order to prevent interference fringes generated when laser light is irradiated. If Ra on the surface of the conductive support 2 is less than 0.04 μm, the effect of preventing interference tends to be insufficient because it is close to a mirror surface. On the other hand, if Ra exceeds 0.5 μm, the image quality tends to be insufficient even if a film is formed. When non-interfering light is used as a light source, it is not particularly necessary to roughen the interference fringes, and it is possible to prevent the occurrence of defects due to irregularities on the surface of the conductive support 2, which 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. Treatment etc. are preferred.

  Further, as another roughening method, a conductive or semiconductive powder is dispersed in a resin without roughening the surface of the conductive support 2 to form a layer on the surface of the support. A method of roughening with fine particles dispersed in the layer is also preferably used.

  The anodizing treatment 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 intact porous anodic oxide film is chemically active, 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. .

  The thickness of the anodized film is preferably 0.3 to 15 μm. When this film thickness is less than 0.3 μm, the barrier property against implantation tends to be poor and the effect tends to be insufficient. On the other hand, when it exceeds 15 μm, there is a tendency that the residual potential increases due to repeated use.

  Further, the conductive support 2 may be subjected to treatment with an acidic aqueous solution or boehmite treatment. The treatment with an acidic treatment liquid comprising 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 to 11% by mass, chromic acid is in the range of 3 to 5% by mass, and hydrofluoric acid is in the range of 0.5 to 2% by mass. The concentration of these acids is preferably in the range of 13.5 to 18% by mass. The treatment temperature is preferably 42 to 48 ° C., but by keeping the treatment temperature high, a thicker film can be formed faster. The film thickness is preferably 0.3 to 15 μm. If it is less than 0.3 μm, the barrier property against injection tends to be poor and the effect tends to be insufficient. On the other hand, when it exceeds 15 μm, there is a tendency that the residual potential increases due to repeated use.

  The boehmite treatment can be performed by immersing in pure water at 90 to 100 ° C. for 5 to 60 minutes, or by contacting with heated steam at 90 to 120 ° C. for 5 to 60 minutes. The film thickness is preferably 0.1 to 5 μm. This may be further anodized using an electrolyte solution with low film solubility such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, citrate, etc. Good.

  The undercoat layer 4 is formed on the conductive support 2. The undercoat layer 4 prevents the injection of charges from the conductive support 2 to the photosensitive layer 3 when the photosensitive layer 3 having a laminated structure is charged, and the photosensitive layer 3 is attached to the conductive support 2. The subbing layer 4 has an action as an adhesive layer that is integrally bonded and held. In some cases, the undercoat layer 4 can exhibit an antireflection effect of light of the conductive support 2. From the viewpoint of having such an effect and maintaining a high-quality image, the electrophotographic photoreceptor according to the present invention preferably includes an undercoat layer.

  Materials for the undercoat layer 4 include acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, and polyvinyl acetate resin. , Vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, polymer resin compound such as melamine resin, zirconium chelate compound, titanium chelate compound, aluminum chelate compound, titanium alkoxide compound, An organic titanium compound, a silane coupling agent, etc. are mentioned. In addition, a charge transporting resin having a charge transporting group, a conductive resin such as polyaniline, or the like can be used. These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds. Among them, a resin insoluble in the solvent contained in the coating liquid for forming the upper layer (in this embodiment, the charge generation layer 5) is preferably used, and in particular, a phenol resin, a phenol-formaldehyde resin, a melamine resin, a urethane resin, an epoxy resin, or the like is preferably used. It is done. Further, zirconium chelate compounds and silane coupling agents are excellent in performance, such as low residual potential, little potential change due to environment, and little potential change due to repeated use.

  Examples of the silane coupling agent include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and γ-glycidoxypropyl. Trimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -Γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, and the like. Among these, vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxy Silane, N-2- (aminoethyl) 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyl Silane coupling agents such as trimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane are preferred.

  Examples of the zirconium chelate compound include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

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

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

  The undercoat layer 4 can contain a conductive substance for improving the photoreceptor characteristics. Examples of the conductive material include metal oxides such as titanium oxide, zinc oxide, and tin oxide, and any known material can be used as long as desired photoreceptor characteristics can be obtained.

  These metal oxides can be surface treated. By performing the surface treatment, resistance value control, dispersibility control, and improvement in photoreceptor characteristics can be achieved. As the surface treatment agent, known materials such as a zirconium chelate compound, a titanium chelate compound, an aluminum chelate compound, a titanium alkoxide compound, an organic titanium compound, and a silane coupling agent can be used. These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds. Among them, the silane coupling agent is excellent in performance such as low residual potential, little potential change due to environment, little potential change due to repeated use, and excellent image quality characteristics.

  Examples of the silane coupling agent, the zirconium chelate compound, the titanium chelate compound, and the aluminum chelate compound include the same substances as those described above.

  As the surface treatment method, any known method can be used, but a dry method or a wet method can be used.

  When surface treatment is performed by a dry method, while stirring the metal oxide fine particles with a mixer having a large shearing force or the like, the silane coupling agent is dissolved directly or dissolved in an organic solvent, and the mixture is added to dry air or nitrogen gas. By spraying together, uniform surface treatment is performed. The dropping of the silane coupling agent and the spraying of the mixture are preferably performed at a temperature not higher than the boiling point of the solvent used. When dripping or spraying is performed at a temperature equal to or higher than the boiling point of the solvent, the solvent evaporates before being uniformly stirred, and the silane coupling agent tends to aggregate locally, making uniform treatment difficult.

  The surface-treated metal oxide particles can be further baked at 100 ° C. or higher. Baking can be 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, metal oxide fine particles are stirred in a solvent, dispersed using ultrasonic waves, a sand mill, an attritor, a ball mill, etc., added with a silane coupling agent solution, stirred or dispersed, and then the solvent is removed. It is processed uniformly by doing. The solvent is preferably distilled off by distillation. In the removal method by filtration, unreacted silane coupling agent tends to flow out, and the amount of silane coupling agent for obtaining desired characteristics tends to be difficult to control. After removing the solvent, baking can be performed at 100 ° C. or higher. Baking can be 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, as a method for removing the metal oxide fine particle-containing water, a method of removing with stirring and heating in a solvent used for surface treatment, a method of removing by azeotropy with a solvent, or the like can be used.

  The amount of the silane coupling agent relative to the metal oxide fine particles in the undercoat layer 4 can be any amount as long as desired electrophotographic characteristics can be obtained. Further, the ratio of the metal oxide fine particles and the resin used in the undercoat layer 4 can be arbitrarily set as long as desired electrophotographic characteristics can be obtained.

  Various organic or inorganic fine powders can be mixed in the undercoat layer 4 for the purpose of improving light scattering properties. Preferred examples of such fine powder include white pigments such as titanium oxide, zinc oxide, zinc sulfide, lead white, and lithopone, inorganic pigments as extender pigments such as alumina, calcium carbonate, and barium sulfate, and polytetrafluoroethylene resin. Examples thereof include particles, benzoguanamine resin particles, and styrene resin particles. The particle size of these fine powders is preferably 0.01 to 2 μm. The fine powder is a component that is added as necessary, but the amount added is preferably 10 to 80% by mass with respect to the solid content contained in the undercoat layer 4, It is more preferable that it is 30-70 mass%.

  In addition, various additives can be used in the coating liquid (coating liquid for forming the undercoat layer) used for forming the undercoat layer 4 in order to improve electrical characteristics, environmental stability, and image quality. Additives include quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, fluorenones such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone Compound, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4-oxadi Azoles, oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) 1,3,4 oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5 ′ tetra-t-butyl Examples thereof include electron transporting substances such as diphenoquinone compounds such as diphenoquinone, electron transporting pigments such as polycyclic condensation systems and azo systems.

  When preparing the coating liquid for forming the undercoat layer, when mixing fine powders such as the above-mentioned conductive substances and light scattering substances, the fine powder is added to the solution in which the resin component is dissolved and the dispersion treatment is performed. It is preferable. As a method for dispersing the fine powder in the resin, 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.

  In addition, as a method for applying the coating liquid for forming the undercoat layer, conventional methods such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method can be used. Can be used.

  The film thickness of the undercoat layer 4 is preferably 0.01 to 50 μm, more preferably 0.05 to 30 μm.

  The charge generation layer 5 includes a charge generation material or includes a charge generation material and a binder resin.

  Charge generation materials include azo pigments such as bisazo and trisazo, condensed aromatic pigments such as dibromoanthanthrone, organic pigments such as perylene pigments, pyrrolopyrrole pigments, and phthalocyanine pigments, and inorganic pigments such as trigonal selenium and zinc oxide. All known ones can be used. As the charge generation material, an inorganic pigment is preferable when a light source with an exposure wavelength of 380 nm to 500 nm is used, and a metal and a metal-free phthalocyanine pigment are preferable when a light source with an exposure wavelength of 700 nm to 800 nm is used.

  In the present embodiment, it is preferable to use a hydroxygallium phthalocyanine pigment having a maximum peak wavelength in the range of 810 to 839 nm in the spectral absorption spectrum in the wavelength range of 600 to 900 nm. Such hydroxygallium phthalocyanine pigments are different from conventional V-type hydroxygallium phthalocyanine pigments, and are preferable because they can provide more excellent dispersibility. Thus, by shifting the maximum peak wavelength of the spectral absorption spectrum to a shorter wavelength side than the conventional V-type hydroxygallium phthalocyanine pigment, it becomes a fine hydroxygallium phthalocyanine pigment in which the crystal arrangement of the pigment particles is suitably controlled, When used as a material for an electrophotographic photosensitive member, it is possible to obtain excellent dispersibility and sufficient sensitivity, chargeability, and dark decay characteristics.

The hydroxygallium phthalocyanine pigment having the maximum peak wavelength in the range of 810 to 839 nm is preferably in a specific range for the average particle diameter and in a specific range for the BET specific surface area. Specifically, the average particle size is preferably 0.20 μm or less, more preferably 0.01 to 0.15 μm, while the BET specific surface area is preferably 45 m ² / g or more, more preferably 50 m ² / g more, and particularly preferably 55~120m ² / g.

When the average particle diameter is larger than 0.20 μm, or when the specific surface area value is less than 45 m ² / g, the pigment particles are coarsened or aggregates of the pigment particles are formed, and the electrophotographic photosensitive member When used as a material, there is a tendency that defects are likely to occur in characteristics such as dispersibility, sensitivity, chargeability, and dark decay characteristics, thereby tending to cause image quality defects.

  The maximum particle size of the hydroxygallium phthalocyanine pigment is preferably 1.2 μm or less, and more preferably 1.0 μm or less. When the maximum particle size exceeds 1.2 μm, minute black spots tend to occur in the formed image.

Furthermore, from the viewpoint of more reliably suppressing density unevenness caused by exposure of the photoreceptor to a fluorescent lamp or the like, the hydroxygallium phthalocyanine pigment has an average particle size of 0.2 μm or less and a maximum particle size of 1.2 μm. And the specific surface area value is preferably 45 m ² / g or more.

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

  Furthermore, the above-mentioned hydroxygallium phthalocyanine pigment preferably has a thermal weight loss rate of 2.0 to 4.0% when heated from 25 ° C to 400 ° C, and is 2.5 to 3.8%. It is more preferable. The thermal weight reduction rate can be measured with a thermobalance or the like.

  When the thermal weight reduction rate exceeds 4.0%, the impurities contained in the hydroxygallium phthalocyanine pigment affect the electrophotographic photosensitive member, and the sensitivity characteristics, potential stability during repeated use, and image quality decrease. Tend to occur. Further, if it is less than 2.0%, the sensitivity tends to be lowered. This is considered due to the fact that the hydroxygallium phthalocyanine pigment exhibits a sensitizing action by interaction with a solvent molecule contained in a small amount in the crystal.

  When the above-mentioned hydroxygallium phthalocyanine pigment is used as a charge generation material for an electrophotographic photoreceptor, it is possible to obtain the optimum sensitivity and excellent photoelectric characteristics of the photoreceptor, and in the binder resin contained in the photosensitive layer. This is particularly effective in terms of excellent image quality characteristics.

  The binder resin for the photosensitive layer includes polycarbonate, polystyrene, polysulfone, polyester, polyimide, polyester carbonate, polyvinyl butyral, methacrylic acid ester polymer, vinyl acetate homopolymer or copolymer, cellulose ester, cellulose ether, polybutadiene. , Polyurethane, phenoxy resin, epoxy resin, silicone resin, fluororesin, and partially crosslinked cured products thereof. One of these can be used alone, or two or more can be used in combination.

  The compounding ratio (weight ratio) between the hydroxygallium phthalocyanine pigment and the binder resin in the charge generation layer 5 is preferably 40: 1 to 1: 4, and more preferably 20: 1 to 1: 2. When the blending amount of the hydroxygallium phthalocyanine pigment exceeds 40 times the blending amount of the binder resin, the dispersibility of the pigment in the dispersion used in the production process of the electrophotographic photoreceptor tends to be insufficient. On the other hand, when the blending amount of the binder resin is less than ¼, the sensitivity of the electrophotographic photosensitive member tends to be insufficient.

  The charge generation layer 5 may contain the hydroxygallium phthalocyanine pigment and a charge generation material other than the hydroxygallium phthalocyanine pigment. Here, as other charge generation materials used for the charge generation layer 5, azo pigments, perylene pigments, condensed aromatic pigments and the like can be used, but it is preferable to use metal-containing or metal-free phthalocyanines. Among them, it is particularly preferable to use a hydroxygallium phthalocyanine pigment, a chlorogallium phthalocyanine pigment, a dichlorotin phthalocyanine pigment or an oxytitanyl phthalocyanine pigment other than the hydroxygallium phthalocyanine pigment having the maximum peak wavelength in the range of 810 to 839 nm. Further, the blending amount of these other charge generation materials is preferably 50% by mass or less based on the total amount of substances contained in the charge generation layer.

  When another layer such as the charge transport layer 6 is further formed on the charge generation layer 5 as in this embodiment, the charge generation layer 5 is dissolved or swollen by the solvent used in the coating solution. In order to avoid this, it is preferable to appropriately select a combination of the binder resin of the charge generation layer 5 and the solvent of the coating solution applied onto the charge generation layer 5.

  The binder resin of the charge generation layer 5 and the binder resin of the charge transport layer 6 to be described later are preferably used in combination with ones whose refractive indexes are close to each other. The difference is preferably 1 or less. When a binder resin having a refractive index close to each other is used in combination, light reflection at the interface between the charge generation layer 5 and the charge transport layer 6 is suppressed, and the interference fringe prevention effect tends to be improved.

  The charge generation layer 5 is formed by adding a charge generation material such as the hydroxygallium phthalocyanine pigment and a binder resin to a predetermined solvent, a sand mill, a colloid mill, an attritor, a dyno mill, a jet mill, a coball mill, a roll mill, an ultrasonic disperser, a gorin The coating liquid obtained by mixing and dispersing using a homogenizer, microfluidizer, optimizer, milder, etc., blade coating method, Meyer bar coating method, spray coating method, dip coating method, bead coating method, air knife It can be obtained by applying and drying by a coating method, a curtain coating method or the like. Here, as a solvent used for the coating liquid of the charge generation layer 5, specifically, methanol, ethanol, n-butanol, benzyl alcohol, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran , Methylene chloride, chloroform, toluene, xylene, chlorobenzene, dimethylformamide, dimethylacetamide, water, and the like. One of these may be used alone, or a mixture of two or more may be used.

  The film thickness of the charge generation layer 5 thus obtained is preferably 0.05 to 5 μm, more preferably 0.1 to 1 μm, from the viewpoint of obtaining good electrical characteristics and image quality. If the film thickness of the charge generation layer 5 is less than 0.05 μm, the sensitivity tends to decrease, and if the film thickness exceeds 5 μm, there is a tendency that adverse effects such as poor chargeability tend to occur.

  The charge transport layer 6 includes a charge transport material and a binder resin, or 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 transporting 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 can be used alone or in combination of two or more.

  A polymer charge transport material can also 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 can be used. In particular, polyester polymer charge transport materials disclosed in JP-A-8-176293, JP-A-8-208820 and the like have a high charge transporting property and are particularly preferable. The polymer charge transport material can be formed by itself, but may be formed by mixing with a binder resin described later.

  Moreover, as a charge transport material, the compound shown by the following general formula (a-1), (a-2) or (a-3) from a mobility viewpoint is preferable.

In the above formula (a-1), R ³⁴ represents a hydrogen atom or a methyl group, and k10 represents 1 or 2. Ar ⁶ and Ar ⁷ are each a substituted or unsubstituted aryl group, —C ₆ H ₄ —C (R ³⁸ ) ═C (R ³⁹ ) (R ⁴⁰ ), or —C ₆ H ₄ —CH═CH—. CH = C (Ar) ₂ represents a substituted amino substituted with a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 1 to 3 carbon atoms Groups. R ³⁸ , R ³⁹ and R ⁴⁰ are a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and Ar is a substituted or unsubstituted aryl group.

In the above formula (a-2), R ³⁵ and R ³⁵ ′ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms, R ³⁶ , R ³⁶ ′. R ³⁷ and R ³⁷ ′ are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted with an alkyl group having 1 to 2 carbon atoms, A substituted aryl group, —C (R ³⁸ ) ═C (R ³⁹ ) (R ⁴⁰ ), or —CH═CH—CH═C (Ar) ₂ , R ³⁸ , R ³⁹ and R ⁴⁰ are each independently A hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, Ar represents a substituted or unsubstituted aryl group. M4 and m5 each independently represents an integer of 0 to 2.

Here, in the formula (a-3), R ⁴¹ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a substituted or unsubstituted aryl group, or —CH═CH. -CH = C (Ar) ₂ is shown. Ar represents a substituted or unsubstituted aryl group. R ⁴² , R ⁴² ′, R ⁴³ , and R ⁴³ ′ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl having 1 to 2 carbon atoms. An amino group substituted with a group, or a substituted or unsubstituted aryl group is shown.

  The binder resin used for the charge transport layer 6 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. Also, as described above, polymer charge transport materials such as polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 can be used. These binder resins can be used alone or in combination of two or more. The compounding ratio of the charge transport material and the binder resin is preferably 10: 1 to 1: 5 by mass ratio.

  The charge transport layer 6 can be formed using a coating liquid in which a charge transport material and a binder resin are dispersed in a predetermined solvent. Solvents include aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, halogenated aliphatic hydrocarbons such as methylene chloride, chloroform and ethylene chloride, tetrahydrofuran and ethyl. Ordinary organic solvents such as cyclic or straight chain ethers such as ether can be used alone or in admixture of two or more.

  The protective layer 7 is preferably configured to include a phenol resin having a charge transporting property and a crosslinked structure. As such a phenol resin, what is comprised including the phenol derivative which has a methylol group, and the charge transport material which has a reactive functional group is preferable. The charge transporting substance having a reactive functional group is preferably incorporated in the crosslinked structure as a constituent component of the phenol resin.

  Examples of the phenol derivative having a methylol group include monomers of monomethylolphenols, dimethylolphenols or trimethylolphenols, mixtures thereof, oligomers thereof, or mixtures of these monomers and oligomers. Such phenol derivatives having a methylol group include resorcin, bisphenol, etc., substituted phenols containing one hydroxyl group such as phenol, cresol, xylenol, paraalkylphenol, paraphenylphenol, and two hydroxyl groups such as catechol, resorcinol, hydroquinone, etc. It is obtained by reacting a compound having a phenol structure, such as substituted phenols, bisphenol A, bisphenol Z, and the like having a phenol structure with formaldehyde, paraformaldehyde, etc. in the presence of an acid catalyst or an alkali catalyst, Generally what is marketed as a phenol resin can also be used. In the present specification, a relatively large molecule having about 2 to 20 repeating molecular structural units is referred to as an oligomer, and a molecule smaller than that is referred to as a monomer.

As the acid catalyst, sulfuric acid, paratoluenesulfonic acid, phosphoric acid and the like are used. Further, as the alkali catalyst, hydroxides or amine catalysts of alkali metals and alkaline earth metals such as NaOH, KOH, Ca (OH) ₂ and Ba (OH) ₂ are used.

  Examples of the amine catalyst include, but are not limited to, ammonia, hexamethylenetetramine, trimethylamine, triethylamine, and triethanolamine. When a basic catalyst is used, the carrier is remarkably trapped by the remaining catalyst, and the electrophotographic characteristics tend to be deteriorated. Therefore, it is preferable to inactivate or remove by neutralizing with an acid or contacting with an adsorbent such as silica gel or an ion exchange resin.

  Examples of the charge transporting substance having a reactive functional group include a charge transporting substance having at least one selected from a hydroxyl group, a carboxyl group, an alkoxysilyl group, an epoxy group, a carbonate group, a thiol group, and an amino group.

式（ＩＶ）中、Ｆは正孔輸送性を有するｎ５価の有機基を、Ｔは２価の基を、Ｙは酸素原子又は硫黄原子を、Ｒ^４、Ｒ^５及びＲ^６はそれぞれ独立に水素原子又は１価の有機基を、Ｒ^７は１価の有機基を、ｍ１は０又は１を、ｎ５は１〜４の整数を、それぞれ示す。但し、Ｒ^６とＲ^７は互いに結合してＹをヘテロ原子とする複素環を形成してもよい。

式（Ｖ）中、Ｆは正孔輸送性を有するｎ６価の有機基を、Ｔは２価の基を、Ｒ^８は１価の有機基を、ｍ２は０又は１を、ｎ６は１〜４の整数を、それぞれ示す。 In addition, as the charge transporting substance having a reactive functional group, a compound represented by the following general formula (I), (II), (III), (IV) or (V) may be used as a film forming property, mechanical strength and It is preferable because of its excellent stability.
_{^{F [- (X 1) n}} -R 1 -Z 1 H] m ... (I)
In the formula (I), F represents an organic group derived from a compound having a hole transport ability, X ¹ represents an oxygen atom or a sulfur atom, R ¹ represents an alkylene group, Z ¹ represents an oxygen atom, a sulfur atom, NH Or COO, n is 0 or 1, and m is an integer of 1 to 4.
_{^{F [- (X 2) n1}} - (R 2) n2 - (Z 2) n3 G] n4 ... (II)
In formula (II), F represents an organic group derived from a compound having a hole transporting ability, X ² represents an oxygen atom or a sulfur atom, R ² represents an alkylene group, Z ² represents an oxygen atom, a sulfur atom, NH Or COO, G represents an epoxy group, n1, n2 and n3 each independently represents 0 or 1, and n4 represents an integer of 1 to 4.
F [—D—Si (R ³ ) _(3-a) Q _a ] _b (III)
In formula (III), F represents an organic group derived from a compound having a hole transporting ability, D represents a divalent group having flexibility, R ³ represents a hydrogen atom, a substituted or unsubstituted alkyl group ( The number of carbon atoms is preferably 1-15, more preferably 1-10, or a substituted or unsubstituted aryl group (carbon number is preferably 6-20, more preferably 6-15), and Q is a hydrolyzable group. A represents an integer of 1 to 3, and b represents an integer of 1 to 4.

In formula (IV), F is an n5-valent organic group having hole transportability, T is a divalent group, Y is an oxygen atom or a sulfur atom, and R ⁴ , R ⁵ and R ⁶ are each independently A hydrogen atom or a monovalent organic group, R ⁷ represents a monovalent organic group, m1 represents 0 or 1, and n5 represents an integer of 1 to 4, respectively. However, R ⁶ and R ⁷ may combine with each other to form a heterocycle having Y as a heteroatom.

In the formula (V), F is an n6 valent organic group having a hole transport property, T is a divalent group, R ⁸ is a monovalent organic group, m2 is 0 or 1, and n6 is 1 to 1. An integer of 4 is shown respectively.

式（ＶＩ）中、Ａｒ^１〜Ａｒ^４は同一でも異なっていてもよく、それぞれ置換又は未置換のアリール基を示し、Ａｒ^５は置換又は未置換のアリール基又はアリーレン基を示し、ｃはそれぞれ独立に０又は１を示し、ｋは０又は１を示し、Ｄは、下記一般式（ＶＩＩ）、（ＶＩＩＩ）、（ＩＸ）、（Ｘ）又は（ＸＩ）で示される１価の有機基を示し、ｃの総数は１〜４である。
−（Ｘ^１）_ｎ−Ｒ^１−Ｚ^１Ｈ …（ＶＩＩ）
式（ＶＩＩ）中、Ｘ^１は酸素原子又は硫黄原子を、Ｒ^１はアルキレン基を、Ｚ^１は酸素原子、硫黄原子、ＮＨ又はＣＯＯを、ｎは０又は１を示す。
−（Ｘ^２）_ｎ１−（Ｒ^２）_ｎ２−（Ｚ^２）_ｎ３Ｇ …（ＶＩＩＩ）
式（ＶＩＩＩ）中、Ｘ^２は酸素原子又は硫黄原子を、Ｒ^２はアルキレン基を、Ｚ^２は酸素原子、硫黄原子、ＮＨ又はＣＯＯを、Ｇはエポキシ基を、ｎ１、ｎ２及びｎ３はそれぞれ独立に０又は１を示す。
−Ｄ−Ｓｉ（Ｒ^３）_{（３-ａ）}Ｑ_ａ …（ＩＸ）
式（ＩＸ）中、Ｄは可とう性を有する２価の基を、Ｒ^３は水素原子、置換若しくは未置換のアルキル基又は置換若しくは未置換のアリール基を、Ｑは加水分解性基を、ａは１〜３の整数を示す。

式（Ｘ）中、Ｔは２価の基を、Ｙは酸素原子又は硫黄原子を、Ｒ^４、Ｒ^５及びＲ^６はそれぞれ独立に水素原子又は１価の有機基を、Ｒ^７は１価の有機基を、ｍ１は０又は１を、それぞれ示す。但し、Ｒ^６とＲ^７は互いに結合してＹをヘテロ原子とする複素環を形成してもよい。

式（ＸＩ）中、Ｔは２価の基を、Ｒ^８は１価の有機基を、ｍ２は０又は１を、それぞれ示す。 Further, among the charge transporting substances represented by the above formulas (I) to (V), more preferred are compounds having a structure represented by the following general formula (VI).

In formula (VI), Ar ^{1 to} Ar ⁴ may be the same or different and each represents a substituted or unsubstituted aryl group, Ar ⁵ represents a substituted or unsubstituted aryl group or an arylene group, and c represents each Independently represents 0 or 1, k represents 0 or 1, D represents a monovalent organic group represented by the following general formula (VII), (VIII), (IX), (X) or (XI) The total number of c is 1 to 4.
_{^{- (X 1) n -R 1}} -Z 1 H ... (VII)
In formula (VII), X ¹ represents an oxygen atom or a sulfur atom, R ¹ represents an alkylene group, Z ¹ represents an oxygen atom, a sulfur atom, NH or COO, and n represents 0 or 1.
_{^{- (X 2) n1 - (}} R 2) n2 - (Z 2) n3 G ... (VIII)
In formula (VIII), X ² represents an oxygen atom or a sulfur atom, R ² represents an alkylene group, Z ² represents an oxygen atom, sulfur atom, NH or COO, G represents an epoxy group, and n1, n2 and n3 each represent Independently represents 0 or 1.
-D-Si (R ³ ) _(3-a) Q _a (IX)
In the formula (IX), D is a divalent group having flexibility, R ³ is a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, Q is a hydrolyzable group, a represents an integer of 1 to 3.

In formula (X), T is a divalent group, Y is an oxygen atom or a sulfur atom, R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom or a monovalent organic group, and R ⁷ is a monovalent group. M1 represents 0 or 1, respectively. However, R ⁶ and R ⁷ may combine with each other to form a heterocycle having Y as a heteroatom.

In formula (XI), T represents a divalent group, R ⁸ represents a monovalent organic group, and m2 represents 0 or 1.

As the substituted or unsubstituted aryl group represented by Ar ^{1 to} Ar ⁴ in the general formula (VI), specifically, an aryl group represented by the following formulas (1) to (7) is preferable.

In formulas (1) to (7), R ⁹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a phenyl group substituted with them. Or an unsubstituted phenyl group or 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, an alkoxy group having 1 to 4 carbon atoms, and 1 carbon atom, respectively. -4 alkoxy groups, phenyl or unsubstituted phenyl groups substituted therewith, aralkyl groups having 7 to 10 carbon atoms or halogen atoms, Ar represents a substituted or unsubstituted arylene group, and D represents the above general formula One of structures represented by formulas (VII) to (XI) is shown, c and s each represent 0 or 1, and t represents an integer of 1 to 3.

  Ar in the aryl group represented by the above formula (7) is preferably an arylene group represented by the following formula (8) or (9).

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

  Moreover, as Z 'in the aryl group represented by the above formula (7), divalent groups represented by the following formulas (10) to (17) are preferable.

In formulas (10) to (17), R ¹⁵ and R ¹⁶ are each substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. A phenyl group, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, or a halogen atom; W represents a divalent group; q and r each represents an integer of 1 to 10; Each represents an integer of 1 to 3.

  In the above formulas (16) to (17), W represents a divalent group represented by the following formulas (18) to (26). In formula (25), u represents an integer of 0 to 3.

In addition, the specific structure of Ar ⁵ in the general formula (VI) is as follows. When k = 0, the structure of c = 1 in the specific structure of Ar ^{1 to} Ar ⁴ and when Ar = 1, the Ar 5 ^The structure of c = 0 in the specific structure of ^{1 to} Ar ⁴ is given.

  Specific examples of the compound represented by the general formula (I) include the following compounds (I-1) to (I-37). In addition, in the following table | surface, although the bond is described, the thing in which the substituent is not described shows a methyl group.

  Specific examples of the compound represented by the general formula (II) include the following compounds (II-1) to (II-47). In the following table, Me or a bond is described but a substituent is not described, a methyl group, Et represents an ethyl group.

Specific examples of the compound represented by the general formula (III) include the following compounds (III-1) to (III-61). The following compounds (III-1) to (III-61) are a combination of Ar ^{1 to} Ar ⁵ and k of the compound represented by the general formula (VI) as shown in the following table, and an alkoxysilyl group. (S) is the specific one shown in the table below.

  Specific examples of the compound represented by the general formula (IV) include the following compounds (IV-1) to (IV-40). In the following table, Me or a bond is described but a substituent is not described, a methyl group, Et represents an ethyl group.

  Specific examples of the compound represented by the general formula (V) include the following compounds (V-1) to (V-55). In the following table, Me or a bond is described but a substituent is not described indicates a methyl group.

In addition, a compound represented by the following general formula (XII) can also be added to the protective layer 7 in order to control various physical properties such as strength and film resistance of the protective layer 7.
Si (R ⁵⁰ ) _(4-c) Q _c (XII)
In the formula (XII), R ⁵⁰ represents a hydrogen atom, an alkyl group or a substituted or unsubstituted aryl group, Q represents a hydrolyzable group, and c represents an integer of 1 to 4.

  Specific examples of the compound represented by the general formula (XII) include the following silane coupling agents. Examples of silane coupling agents include tetrafunctional silanes such as tetramethoxysilane and tetraethoxysilane (c = 4); methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, methyltrimethoxyethoxysilane, vinyltri Methoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxy Silane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, (tridecafluoro-1,1,2,2-tetrahydrooctyl L) Triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, 3- (heptafluoroisopropoxy) propyltriethoxysilane, 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane, 1H , 1H, 2H, 2H-perfluorodecyltriethoxysilane, trifunctional alkoxysilanes such as 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (c = 3); dimethyldimethoxysilane, diphenyldimethoxysilane, methyl And bifunctional alkoxysilanes such as phenyldimethoxysilane (c = 2); monofunctional alkoxysilanes such as trimethylmethoxysilane (c = 1), and the like. Trifunctional and tetrafunctional alkoxysilanes are preferable for improving the strength of the film, and monofunctional and bifunctional alkoxysilanes are preferable for improving the flexibility and film formability.

  The silane coupling agent can be used in any amount, but when a fluorine-containing compound is used, the content of the fluorine-containing compound is preferably 0.25 times or less by mass with respect to the compound not containing fluorine. When this content is exceeded, a problem may occur in the film formability of the crosslinked film.

  In addition, a silicon-based hard coat agent produced mainly from these coupling agents can also be used. Commercially available hard coat agents include KP-85, X-40-9740, X-40-2239 (manufactured by Shin-Etsu Silicone), and AY42-440, AY42-441, AY49-208 (manufactured by Toray Dow Corning). Etc.) can be used.

In order to increase the strength of the protective layer 7, it is also preferable to use a compound having two or more silicon atoms as shown in the following general formula (XIII).
B- (Si (R ⁵¹ ) _(3-d) Q _d ) ₂ (XIII)

In the above formula (XIII), B represents a divalent organic group, R ⁵¹ represents a hydrogen atom, an alkyl group or a substituted or unsubstituted aryl group, Q represents a hydrolyzable group, and d represents an integer of 1 to 3. Show. More specific examples of the compound represented by the general formula (XIII) include the following compounds (XIII-1) to (XIII-16).

  Various resins can be added for the purposes of discharge gas resistance, mechanical strength, scratch resistance, particle dispersibility, viscosity control, torque reduction, wear amount control, pot life extension, and the like. In the present embodiment, it is preferable to further add a resin that dissolves in alcohol. Examples of resins soluble in alcohol solvents include polyvinyl butyral resins, polyvinyl formal resins, and polyvinyl acetal resins such as partially acetalized polyvinyl acetal resins in which a part of butyral is modified with formal or acetoacetal (for example, manufactured by Sekisui Chemical Co., Ltd.). ESREC B, K, etc.), polyamide resin, cellulose resin, polyvinylphenol resin and the like. In particular, polyvinyl acetal resin and polyvinyl phenol resin are preferable from the viewpoint of improving electrical characteristics.

  The molecular weight of the resin is preferably 2000-100000, more preferably 5000-50000. If the molecular weight is less than 2,000, the desired effect tends to be lost, and if it is more than 100,000, the solubility tends to be low and the addition amount is limited, or the film formation tends to be poor during application. The addition amount is preferably 1 to 40% by mass, more preferably 1 to 30% by mass, and most preferably 5 to 20% by mass. When the addition amount is less than 1% by mass, it is difficult to obtain a desired effect. When the addition amount is more than 40% by mass, image blurring at high temperature and high humidity is likely to occur. Moreover, although said resin may be used independently, you may mix and use them.

上記式（ＸＩＶ）中、Ａ^１及びＡ^２は、それぞれ独立に一価の有機基を示す。 In order to extend the pot life and control the film properties, it is preferable to contain a cyclic compound having a repeating structural unit represented by the following general formula (XIV) or a derivative thereof.

In the above formula (XIV), A ¹ and A ² each independently represent a monovalent organic group.

  Examples of the cyclic compound having a repeating structural unit represented by the general formula (XIV) include commercially available cyclic siloxanes. Specifically, cyclic dimethylcyclosiloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, 1,3,5-trimethyl-1,3,5- Triphenylcyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclotetrasiloxane, 1,3,5,7,9-pentamethyl-1,3,5,7 , 9-pentaphenylcyclopentasiloxane and other cyclic methylphenylcyclosiloxanes, hexaphenylcyclotrisiloxane and other cyclic phenylcyclosiloxanes, and 3- (3,3,3-trifluoropropyl) methylcyclotrisiloxane and other fluorine Atom-containing cyclosiloxanes, methylhydrosiloxa Mixture, pentamethylcyclopentasiloxane, mention may be made of phenyl hydrosilyl group-containing cyclosiloxanes of hydrocyclosiloxane like, cyclic siloxanes and vinyl group-containing cyclosiloxanes such as penta vinyl pentamethylcyclopentasiloxane like. These cyclic siloxane compounds may be used alone or in combination of two or more.

  Further, various fine particles can be added to the protective layer 7 in order to control the contamination resistance adhesion, lubricity, hardness and the like of the electrophotographic photosensitive member surface. These fine particles may be used alone or in combination of two or more.

  Examples of the fine particles include silicon atom-containing fine particles or fluorine atom-containing resin particles. The silicon atom-containing fine particles are fine particles containing silicon as a constituent element, and specific examples include colloidal silica and silicone fine particles. The colloidal silica used as the silicon atom-containing fine particles preferably has a volume average particle diameter of 1 to 100 nm, more preferably 10 to 30 nm, in an acidic or alkaline aqueous dispersion, or an organic solvent such as alcohol, ketone or ester. It is selected from those dispersed in, and commercially available products can be used. The solid content of colloidal silica in the protective layer 7 is not particularly limited, but preferably 0.1 to 0.1 based on the total solid content of the protective layer 7 in terms of film formability, electrical characteristics, and strength. It is used in the range of 50% by mass, more preferably in the range of 0.1-30% by mass.

  Silicone fine particles used as silicon atom-containing fine particles are spherical and preferably have a volume average particle diameter of 1 to 500 nm, more preferably 10 to 100 nm, and are selected from silicone resin particles, silicone rubber particles, and silicone surface-treated silica particles. A commercially available product can be used.

  Silicone fine particles are small particles that are chemically inert and excellent in dispersibility in resin, and since the content required to obtain sufficient characteristics is low, the electron does not hinder the crosslinking reaction, The surface properties of the photographic photoreceptor can be improved. In other words, in a state in which it is uniformly incorporated into a strong cross-linked structure, it improves the lubricity and water repellency of the surface of the electrophotographic photosensitive member, and maintains good wear resistance and contamination resistance adhesion over a long period of time. Can do. The content of the silicone fine particles in the protective layer 7 is preferably in the range of 0.1 to 30% by mass, more preferably in the range of 0.5 to 10% by mass based on the total solid content of the protective layer 7. .

  Fluorine atom-containing resin particles include fluorine-based fine particles such as ethylene tetrafluoride, ethylene trifluoride, propylene hexafluoride, vinyl fluoride, vinylidene fluoride, and the 8th Polymer Materials Forum Lecture Proceedings p89. And fine particles made of a resin obtained by copolymerizing a fluororesin and a monomer having a hydroxyl group.

Other fine particles include ZnO—Al ₂ O ₃ , SnO ₂ —Sb ₂ O ₃ , In ₂ O ₃ —SnO ₂ , ZnO—TiO ₂ , ZnO—TiO ₂ , MgO—Al ₂ O ₃ , FeO—. Examples thereof include semiconductive metal oxides such as TiO ₂ , TiO ₂ , SnO ₂ , In ₂ O ₃ , ZnO, and MgO.

  For the same purpose, an oil such as silicone oil can be added. Examples of the silicone oil include silicone oils such as dimethylpolysiloxane, diphenylpolysiloxane, and phenylmethylsiloxane, amino-modified polysiloxane, epoxy-modified polysiloxane, carboxyl-modified polysiloxane, carbinol-modified polysiloxane, methacryl-modified polysiloxane, and mercapto. Examples include reactive silicone oils such as modified polysiloxanes and phenol-modified polysiloxanes. These may be added in advance to the protective layer-forming coating solution, or may be impregnated under reduced pressure or increased pressure after producing the photoreceptor.

  Moreover, the protective layer 7 can also contain additives, such as a plasticizer, a surface modifier, antioxidant, and a photodegradation inhibitor. Examples of the plasticizer include biphenyl, biphenyl chloride, terphenyl, dibutyl phthalate, diethylene glycol phthalate, dioctyl phthalate, triphenyl phosphate, methyl naphthalene, benzophenone, chlorinated paraffin, polypropylene, polystyrene, and various fluorohydrocarbons.

  It is particularly preferable to add an antioxidant to the protective layer 7 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 in the protective layer 7 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′-hexamethylenebis (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-tert-butylphenol), 2,5-di-tert-amylhydroquinone, 2-tert-butyl-6- (3-butyl) -2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 4,4'-butylidenebis (3-methyl-6-t-butylphenol), and the like.

  Further, commercially available hindered phenol-based antioxidants include, for example, “Sumilizer BHT-R”, “Sumilizer MDP-S”, “Sumilizer BBM-S”, “Sumizer WX-R”. , "Sumizer NW", "Sumizer BP-76", "Sumizer BP-101", "Sumizer GA-80", "Sumizer GM", "Sumizer GS", Sumitomo Chemical Co., Ltd., "IRGANOX1010", "IRGANOX" “IRGANOX1076”, “IRGANOX1098”, “IRGANOX1135”, “IRGANOX1141”, “IRGANOX1222”, “IRGANOX1330”, “IR “ANOX1425WL”, “IRGANOX1520L”, “IRGANOX245”, “IRGANOX259”, “IRGANOX3114”, “IRGANOX3790”, “IRGANOX5057”, “IRGANOX565” or more, manufactured by Ciba Specialty Chemicals, “Adekastab AO-20” ”,“ ADK STAB AO-40 ”,“ ADK STAB AO-50 ”,“ ADK STAB AO-60 ”,“ ADK STAB AO-70 ”,“ ADK STAB AO-80 ”,“ ADK STAB AO-330 ”or more, manufactured by Asahi Denka Co., Ltd. As the dirt amine system, “Sanol LS2626”, “Sanol LS765”, “Sanol LS770”, “Sanol LS744” or more manufactured by Sankyo Lifetech Co., Ltd., “Tinubin 144”, “ Tinuvin 622LD "or more manufactured by Ciba Specialty Chemicals," Mark LA57 "," Mark LA67 "," Mark LA62 "," Mark LA68 "," Mark LA63 "or more manufactured by Asahi Denka Co., Ltd." Sumilyzer TPS "or more manufactured by Sumitomo Chemical Co., Ltd. As a thioether type, “Sumilyzer TP-D” or more manufactured by Sumitomo Chemical Co., Ltd., and as a phosphite type, “Mark 2112”, “Mark PEP · 8”, “Mark PEP · 24G”, “Mark PEP · 36”, “Mark 329K”, “Mark HP · 10” or more are manufactured by Asahi Denka Co., Ltd. Furthermore, these may be modified with a substituent such as an alkoxysilyl group capable of undergoing a crosslinking reaction with the material forming the crosslinked film.

  The protective layer 7 includes polyvinyl butyral resin, polyarylate resin (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin An insulating resin such as a resin, polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, or polyvinyl pyrrolidone resin may be contained. In this case, the insulating resin can be added at a desired ratio, and thereby, adhesion to the charge transport layer 6, coating film defects due to heat shrinkage and repellency, and the like can be suppressed.

  Further, conductive particles may be added to the protective layer 7 in order to reduce the residual potential. Examples of the conductive particles include metals, metal oxides, and carbon black, but metals or metal oxides are more preferable. 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 can 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.

  The protective layer 7 is formed using a coating liquid for forming a protective layer containing the above-described constituent materials.

  Since the protective layer 7 is formed using the above-described charge transporting substance having a reactive functional group, a catalyst is added to the protective layer forming coating solution, or the catalyst is added during the preparation of the protective layer forming coating solution. It is preferable to use it. Catalysts used include inorganic acids such as hydrochloric acid, acetic acid, phosphoric acid and sulfuric acid, organic acids such as formic acid, propionic acid, oxalic acid, paratoluenesulfonic acid, benzoic acid, phthalic acid and maleic acid, potassium hydroxide, water An alkali catalyst such as sodium oxide, calcium hydroxide, ammonia, triethylamine, or a solid catalyst insoluble in the system can also be used.

  Moreover, when forming the protective layer 7 using the above-mentioned phenol resin and a charge transporting substance having a reactive functional group, from the viewpoint of further reducing the residual potential, an organic sulfonic acid and / or a derivative thereof is used as a catalyst. It is preferable to use it. Examples of the organic sulfonic acid and derivatives thereof include paratoluenesulfonic acid, zinc phenolsulfonate, dodecylbenzenesulfonic acid, and the like.

  The amount of the organic sulfonic acid and / or derivative thereof to be blended in the coating solution for forming the protective layer is preferably such that the content of the organic sulfonic acid and / or derivative thereof contained in the protective layer 7 is based on the total solid content of the protective layer 7. Is set to be in the range of 0.01 to 0.25% by mass, more preferably 0.01 to 0.10% by mass. By forming a photosensitive layer satisfying the above formulas (1) and (2) using an organic sulfonic acid and / or a derivative thereof so as to have such a content, both reduction of residual potential and light fatigue resistance are improved. It can be made compatible at the level. If the content is less than 0.01% by mass, the residual potential reducing effect tends to be difficult to obtain. On the other hand, if the content exceeds 0.25% by mass, the above formulas (1) and ( It becomes difficult to satisfy 2), and it tends to be difficult to reduce the residual potential while sufficiently suppressing density unevenness.

  Furthermore, when the coating liquid for forming the protective layer contains an organic sulfonic acid and / or a derivative thereof, this exhibits an excellent function as a curing catalyst for the phenol resin, and sufficiently promotes the curing reaction of the phenol resin. The mechanical strength of the protective layer formed can be further improved. Furthermore, the organic sulfonic acid and / or the derivative thereof exhibits an excellent function as a dopant for the charge transporting substance having the reactive functional group, and can further improve the electrical characteristics of the formed protective layer. .

  In addition, in order to remove the catalyst at the time of synthesis from a phenol derivative having a methylol group, the phenol derivative is dissolved in a suitable solvent such as methanol, ethanol, toluene, ethyl acetate, washed with water, reprecipitation using a poor solvent, etc. It is preferable to perform the above treatment or to perform treatment using an ion exchange resin or an inorganic solid.

  For example, as an ion exchange resin, Amberlite 15, Amberlite 200C, Amberlyst 15E (above, manufactured by Rohm and Haas); Dowex MWC-1-H, Dowex 88, Dowex HCR-W2 (above Levacit SPC-108, Levacit SPC-118 (above, Bayer); Diaion RCP-150H (Mitsubishi Kasei); Sumikaion KC-470, Duolite C26-C, Duolite C-433, Duolite-464 (above, manufactured by Sumitomo Chemical Co., Ltd.); Cation exchange resins such as Nafion-H (DuPont); Amberlite IRA-400, Amberlite IRA-45 (above, Rohm and Anion exchange resins such as (made by Haas) are listed.

Further, as the inorganic solid, an inorganic solid in which a group containing a protonic acid group such as Zr (O ₃ PCH ₂ CH ₂ SO ₃ H) ₂ or Th (O ₃ PCH ₂ CH ₂ COOH) ₂ is bonded to the surface. A polyorganosiloxane containing a protonic acid group such as a polyorganosiloxane having a sulfonic acid group; a heteropolyacid such as cobalt tungstic acid or phosphomolybdic acid; an isopolyacid such as niobic acid, tantalic acid or molybdic acid; silica gel, alumina, Single metal oxides such as chromia, zirconia, CaO, MgO; complex metal oxides such as silica-alumina, silica-magnesia, silica-zirconia, zeolites; clay minerals such as acid clay, activated clay, montmorillonite, and kaolinite ; LiSO _4, metal sulfates MgSO ₄ and the like; phosphoric acid zirconium, phosphorus Metal phosphates such as lanthanum; coupled to on silica gel by reacting aminopropyltriethoxysilane containing an amino group such as the resulting solid which groups _{surface; LiNO 3, Mn (NO 3} ) 2 and the like of a metal nitrate Inorganic solids such as polyorganosiloxanes containing amino groups such as amino-modified silicone resins.

  For the coating liquid for forming the protective layer, various solvents such as alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; tetrahydrofuran; ethers such as diethyl ether and dioxane, etc. Can be used. In order to apply a dip coating method generally used for production of an electrophotographic photosensitive member, an alcohol solvent, a ketone solvent, or a mixed solvent thereof is preferable. In addition, the boiling point of the solvent used is preferably 50 to 150 ° C., and these can be arbitrarily mixed and used.

  In addition, since an alcohol solvent, a ketone solvent, or a mixed solvent thereof is preferable as the solvent, the charge transporting substance used for forming the protective layer is preferably soluble in these solvents.

  The amount of the solvent can be set arbitrarily, but if the amount is too small, the constituent materials are likely to be precipitated. Therefore, the amount of the solvent is preferably 0.5 to 30 mass with respect to the total 1 mass part of the solid content contained in the coating liquid for forming the protective layer. Parts, more preferably 1 to 20 parts by mass.

  Coating methods for forming a protective layer using a coating solution for forming a protective layer include blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating. A usual method such as can be used. However, when a required film thickness cannot be obtained by a single application, the necessary film thickness can be obtained by applying a plurality of times. In addition, when performing the multiple application | coating several times, a heat processing may be performed every time of application | coating, and may be after carrying out multiple application | coating several times.

  Further, since the protective layer 7 formed from the above-mentioned coating solution for forming a protective layer has excellent mechanical strength and sufficient photoelectric properties, it can be used as it is as a charge transport layer of a multilayer photoreceptor. it can.

  The photosensitive layer 3 can contain at least one electron accepting substance for the purpose of improving sensitivity, reducing residual potential, reducing fatigue during repeated use, and the like.

Examples of the electron acceptor include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene, Examples include chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, and phthalic acid. Of these, fluorenone-based, quinone-based, and benzene derivatives having an electron-withdrawing substituent such as Cl, CN, NO ₂ are particularly preferable.

  The photosensitive layer 3 may be added with an antioxidant, a light stabilizer, a heat stabilizer, etc. for the purpose of preventing deterioration of the photoreceptor due to ozone, oxidizing gas, or light or heat generated in the image forming apparatus. An agent can be added.

  Examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds. Examples of the light stabilizer include derivatives such as benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine.

  Furthermore, if the protective layer 7 which is the outermost layer of the electrophotographic photosensitive member 1 is treated with an aqueous dispersion containing a fluorine-based resin, torque required for rotation of the electrophotographic photosensitive member can be reduced and transfer efficiency can be improved. preferable.

  The electrophotographic photoreceptor 1 requires that the photosensitive layer 3 satisfies the following conditions.

That is, the photosensitive layer was exposed for 10 minutes to white light of R0 (Ω · cm) and 1000 Lux of volume resistivity per 1 cm ² of the surface of the photosensitive layer 3 measured in an environment of a temperature of 22 ° C. and a humidity of 55% RH. When the volume resistivity per 1 cm ² of surface 3 is R1 (Ω · cm), the following formulas (1) and (2) must be satisfied.
3.7 × 10 ¹⁰ Ω · cm ≦ R0 ≦ 8.9 × 10 ¹⁰ Ω · cm (1)
0.1 ≦ (R1 / R0) ≦ 0.71 (2)

  Whether the photosensitive layer 3 satisfies the above formulas (1) and (2) can be confirmed by the following method.

First, an area of 3 cm ^{2 on} the surface of the photosensitive layer 3 is irradiated with white light with an illuminance of 1000 Lux (for example, a halogen lamp, a fluorescent lamp, an incandescent lamp, etc.) for 10 minutes. A 1 cm ² (1 cm × 1 cm) electrode was attached to the surface of the exposed portion, and a frequency response analyzer (for example, “1260 type”, manufactured by Solartron) was used in an environment of a temperature of 22 ° C. and a humidity of 55% RH. The volume resistivity R1 is obtained by measuring the volume resistivity 100 times under the conditions of 1 Hz and a sine waveform (sin waveform) 1 V and obtaining an average value. Further, a volume resistivity R0 is obtained by attaching a 1 cm ² electrode to the surface of the non-exposed portion and measuring the volume resistivity under the same conditions as described above. And what is necessary is just to substitute the obtained R0 and R1 into said Formula (1) and (2).

  Since the photosensitive layer satisfying the above formulas (1) and (2) can be confirmed by such a method, the composition of the photosensitive layer 3 according to the present invention is determined while appropriately adjusting the constituent components of the photosensitive layer. Can do.

  In addition, the above method can also be used as a method for evaluating the light fatigue resistance of an electrophotographic photoreceptor, and an electrophotographic photoreceptor excellent in light fatigue resistance can be obtained more easily and reliably.

(Image forming apparatus and process cartridge)
FIG. 4 is a schematic diagram showing a preferred embodiment of an image forming apparatus for forming an image based on the image forming method of the present invention. An image forming apparatus 100 illustrated in FIG. 4 includes a process cartridge 20 including an electrophotographic photosensitive member 1, an exposure device 30, a transfer device 40, and an intermediate transfer member 50 in an image forming apparatus main body (not shown). . In the image forming apparatus 100, the exposure device 30 is disposed at a position where the electrophotographic photosensitive member 1 can be exposed from the opening of the process cartridge 20, and the transfer device 40 is interposed between the electrophotographic photosensitive member via the intermediate transfer member 50. The intermediate transfer member 50 is disposed such that a part of the intermediate transfer member 50 can come into contact with the electrophotographic photosensitive member 1.

  The process cartridge 20 is obtained by integrating a charging device 21, a developing device 25, and a cleaning device 27 together with an electrophotographic photosensitive member 1 by a mounting rail in a case. The case is provided with an opening for exposure.

  As the charging device 21, for example, a contact charger using a conductive or semiconductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube or the like can be used. Further, a non-contact type roller charger using a charging roller in the vicinity of the photoreceptor 1, a known charger such as a scorotron charger using a corona discharge or a corotron charger can be used.

  As the developing device 25, for example, a general developing device that performs development by bringing a magnetic or non-magnetic one-component developer or two-component developer into contact or non-contact with each other can be used. Such a developing device is not particularly limited as long as it has the functions described above, and can be appropriately 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 photosensitive member 1 using a brush, a roller, or the like can be used.

  Examples of the exposure apparatus 30 include optical system devices that can expose the surface of the photoreceptor 1 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 to 450 nm as a blue laser can be used. For color image formation, a surface-emitting laser light source capable of multi-beam output is also effective.

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

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

  In addition to the above-described devices, the image forming apparatus 100 may include, for example, an optical static elimination device that performs optical static elimination on the photoreceptor 1.

  FIG. 5 is a schematic diagram showing another embodiment of the image forming apparatus according to the present invention. In the image forming apparatus 110 shown in FIG. 5, the electrophotographic photosensitive member 1 is fixed to the main body of the image forming apparatus, and the charging device 22, the developing device 25, and the cleaning device 27 are each formed into a cartridge. It is provided independently as a cleaning cartridge. Note that the charging device 22 includes a charging device for charging by a corona discharge method.

  In the image forming apparatus 110, the electrophotographic photosensitive member 1 and other apparatuses are separated, and the charging device 22, the developing device 25, and the cleaning device 27 are fixed to the image forming apparatus main body by screws, caulking, adhesion, or welding. It is possible to detach it by the operation by pulling out and pushing in without being done.

  In the image forming apparatus according to the present invention, the electrophotographic photosensitive member 1 has a protective layer having a crosslinked structure, and can sufficiently suppress wear on the surface of the photosensitive member. The electrophotographic photosensitive member 1 can sufficiently suppress the occurrence of image quality defects such as density unevenness even when exposed to light such as a fluorescent lamp, has excellent light fatigue resistance, and has a long life. Thereby, there is a case where it is not necessary to make a cartridge. Therefore, the charging device 22, the developing device 25, or the cleaning device 27 can be detached and attached by an operation by pulling out and pushing in without being fixed to the main body by screws, caulking, adhesion, or welding. The member cost per hit can be reduced. Further, two or more of these devices can be detachable as an integrated cartridge, thereby further reducing the member cost per print.

  The image forming apparatus 110 has the same configuration as that of the image forming apparatus 100 except that the charging device 22, the developing device 25, and the cleaning device 27 are each formed as a cartridge.

  FIG. 6 is a schematic view showing another embodiment of the image forming apparatus according to the present invention. The image forming apparatus 120 is a tandem full-color image forming apparatus equipped with four process cartridges 20. In the image forming apparatus 120, four process cartridges 20 are arranged in parallel on the intermediate transfer member 50, and one electrophotographic photosensitive member can be 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.

  The tandem image forming apparatus 120 includes the electrophotographic photosensitive member of the present invention as a photosensitive member for forming a toner image of each color, so that a single-color photosensitive member is exposed to light during cartridge replacement or maintenance work. Even if it exists, it can suppress sufficiently that the hue of a print image changes, and a stable image can be obtained.

  FIG. 7 is a schematic view showing another embodiment of the image forming apparatus of the present invention. The image forming apparatus 130 shown in FIG. 7 is a so-called four-cycle image forming apparatus that forms toner images of a plurality of colors with one electrophotographic photosensitive member. The image forming apparatus 130 includes a photosensitive drum 1 that is rotated by a driving device (not shown) at a predetermined rotational speed in the direction of arrow A in the figure, and above the photosensitive drum 1 is a photosensitive member. A charging device 22 for charging the outer peripheral surface of the drum 1 is provided. The photosensitive drum 1 has the same configuration as the electrophotographic photosensitive member 1.

  Further, an exposure device 30 having a surface emitting laser array as an exposure light source is disposed above the charging device 22. The exposure device 30 modulates a plurality of laser beams emitted from a light source in accordance with an image to be formed and deflects the laser beams in the main scanning direction so that the axis of the photosensitive drum 1 is on the outer peripheral surface of the photosensitive drum 1. Scan in parallel. Thereby, an electrostatic latent image is formed on the outer peripheral surface of the charged photosensitive drum 1.

  A developing device 25 is disposed on the side of the photosensitive drum 1. The developing device 25 includes a roller-shaped container that is rotatably arranged. Four containers are formed inside the container, and developing units 25Y, 25M, 25C, and 25K are provided in each container. The developing devices 25Y, 25M, 25C, and 25K each include a developing roller 26, and store Y, M, C, and K color toners therein.

  The full-color image is formed by the image forming apparatus 130 while the photosensitive drum 1 is rotated four times. That is, during four rotations of the photosensitive drum 1, the charging device 22 charges the outer peripheral surface of the photosensitive drum 1, and the exposure device 20 includes Y, M, C, K image data representing a color image to be formed. Scanning the outer peripheral surface of the photosensitive drum 1 with the laser beam modulated according to any one is repeated while switching the image data used for modulation of the laser beam each time the photosensitive drum 1 rotates. Further, the developing device 25 operates the developing device corresponding to the outer peripheral surface in a state where any of the developing rollers 26 of the developing devices 25Y, 25M, 25C, and 25K corresponds to the outer peripheral surface of the photosensitive drum 1. The photosensitive drum 1 is the one that develops the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 1 to a specific color and forms a toner image of the specific color on the outer peripheral surface of the photosensitive drum 1. Each time it rotates, the process is repeated while rotating the container so that the developing unit used for developing the electrostatic latent image is switched. Thus, every time the photosensitive drum 1 rotates, Y, M, C, and K toner images are formed on the outer peripheral surface of the photosensitive drum 1.

  An endless intermediate transfer belt 50 is disposed substantially below the photosensitive drum 1. The intermediate transfer belt 50 is wound around rollers 51, 53, and 55, and is disposed so that the outer peripheral surface is in contact with the outer peripheral surface of the photosensitive drum 1. The rollers 51, 53, and 55 are rotated by a driving force of a motor (not shown) and rotate the intermediate transfer belt 50 in the direction of arrow B in FIG.

  A transfer device (transfer device) 40 is disposed on the opposite side of the photosensitive drum 1 across the intermediate transfer belt 50, and the toner image formed on the outer peripheral surface of the photosensitive drum 1 is intermediate transferred by the transfer device 40. The image is transferred onto the image forming surface of the belt 50. The intermediate transfer belt 50 is also rotated in accordance with the rotation of the photosensitive drum 1, and a full-color toner image is formed on the intermediate transfer belt 50 when the photosensitive drum 1 is rotated four times.

  A lubricant supply device 31 and a cleaning device 27 are disposed on the outer peripheral surface of the photosensitive drum 1 on the opposite side of the developing device 25 with the photosensitive drum 1 interposed therebetween. When the toner image formed on the outer peripheral surface of the photosensitive drum 12 is transferred to the intermediate transfer belt 50, the lubricant is supplied to the outer peripheral surface of the photosensitive drum 1 by the lubricant supply device 31, and the The area carrying the transferred toner image is cleaned by the cleaning device 27.

  A tray 60 is disposed below the intermediate transfer belt 50, and a large number of sheets P as recording materials are accommodated in the tray 60 in a stacked state. A take-out roller 61 is disposed obliquely above and to the left of the tray 60, and a roller pair 63 and a roller 65 are arranged in this order on the downstream side in the take-out direction of the paper P by the take-out roller 61. The uppermost recording sheet in the stacked state is taken out from the tray 60 by the take-out roller 61 rotating, and is conveyed by the roller pair 63 and the roller 65.

  A transfer device 42 is disposed on the opposite side of the roller 55 with the intermediate transfer belt 50 interposed therebetween. The paper P conveyed by the roller pair 63 and the roller 65 is sent between the intermediate transfer belt 50 and the transfer device 42, and the toner image formed on the image forming surface of the intermediate transfer belt 50 is transferred by the transfer device 42. . A fixing device 44 having a pair of fixing rollers is arranged on the downstream side of the transfer device 42 in the conveyance direction of the paper P. The paper P on which the toner image is transferred is transferred by the fixing device 44. After being fused and fixed, the sheet is discharged out of the image forming apparatus 130 and placed on a discharge tray (not shown).

  As the fixing device 44, for example, a commonly used device such as a heat roll fixing device or an oven fixing device can be used. The toner image transferred onto the transfer medium can be fixed by the fixing device 44.

(Process cartridge)
Next, the process cartridge according to the present invention will be described. FIG. 8 is a schematic diagram showing a basic configuration of a preferred embodiment of the process cartridge according to the present invention.

  The process cartridge 300 is combined and integrated in the case 311 together with the electrophotographic photosensitive member 1 using the charging device 21, the exposure device 30, the developing device 25, the cleaning device 27, and the mounting rail 313. The process cartridge 300 is detachable from the main body of the image forming apparatus including the transfer device 40, the fixing device 44, and other components (not shown), and constitutes the image forming apparatus together with the main body of the image forming apparatus. To do.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

<Synthesis of hydroxygallium phthalocyanine>
(Type I hydroxygallium phthalocyanine)
30 parts by mass of 1,3-diiminoisoindoline and 9.1 parts by mass of gallium trichloride were added to 230 parts by mass of dimethyl sulfoxide and reacted by stirring at 160 ° C. for 6 hours to obtain red-violet crystals. The obtained crystals were washed with dimethyl sulfoxide, then washed with ion-exchanged water, and dried to obtain 28 parts by mass of crude crystals of type I chlorogallium phthalocyanine.

  Next, 10 parts by mass of the obtained crude crystals of type I chlorogallium phthalocyanine sufficiently dissolved in 300 parts by mass of sulfuric acid (concentration 97%) heated to 60 ° C. were ion-exchanged with 600 parts by mass of 25% aqueous ammonia. It was dripped in the mixed solution with 200 mass parts of water. Subsequently, the precipitated crystals were collected by filtration, further washed with ion exchange water, and dried to obtain 8 parts by mass of I-type hydroxygallium phthalocyanine.

(Hydroxygallium phthalocyanine-1)
Using a glass ball mill, 6 parts by mass of the above-obtained I-type hydroxygallium phthalocyanine together with 90 parts by mass of N, N-dimethylformamide and 350 parts by mass of glass spherical media having an outer diameter of 0.9 mm was obtained at 25 ° C. For 48 hours. The progress of crystal conversion was monitored by measuring the absorption wavelength of the wet pulverization treatment liquid, and it was confirmed that the maximum peak wavelength λ _MAX in the range of 600 to 900 nm of the spectral absorption spectrum of hydroxygallium phthalocyanine was 827 nm. The spectral absorption spectrum was measured using a U-2000 type spectrophotometer manufactured by Hitachi, Ltd., and the measurement liquid was prepared by dispersing 0.6 g of hydroxygallium phthalocyanine pigment in 8 mL of n-butyl acetate at room temperature.

Next, the obtained crystal was washed with acetone and dried to obtain 7.5 °, 9.9 °, 12.5 °, 16 ° Bragg angles (2θ ± 0.2 °) with respect to CuKα characteristic X-rays. 5.5 parts by mass of hydroxygallium phthalocyanine having diffraction peaks at .3 °, 18.6 °, 25.1 °, and 28.3 ° were obtained. The obtained hydroxygallium phthalocyanine pigment had a BET specific surface area of 67.7 m ² / g, a maximum particle size of 0.8 μm, and an average particle size of 0.1 μm. This hydroxygallium phthalocyanine was designated as “hydroxygallium phthalocyanine-1”.

The X-ray diffraction spectrum was measured by the powder method using CuKα characteristic X-rays under the following conditions.
Measuring instrument: X-ray diffractometer Miniflex manufactured by Rigaku Corporation
X-ray tube: Cu
Tube current: 15 mA
Scan speed: 5.0 deg. / Min
Sampling interval: 0.02 deg.
Start angle (2θ): 5 deg.
Stop angle (2θ): 35 deg.
Step angle (2θ): 0.02 deg.

  The BET specific surface area was measured using a BET specific surface area measuring instrument (Flow Soap II 2300, manufactured by Shimadzu Corporation), and the average particle diameter was measured by a laser diffraction scattering type particle size distribution analyzer (LA-700, Horiba, Ltd.). ).

(Hydroxygallium phthalocyanine-2)
Using a glass ball mill, 6 parts by mass of the I-type hydroxygallium phthalocyanine obtained above, together with 90 parts by mass of N, N-dimethylformamide and 350 parts by mass of glass spherical media having an outer diameter of 5.5 mm, For 48 hours. The progress of the crystal conversion was monitored by measuring the absorption wavelength of the wet pulverized liquid, and it was confirmed that the maximum peak wavelength λ _MAX in the range of 600 to 900 nm of the spectral absorption spectrum of hydroxygallium phthalocyanine was 832 nm. The spectral absorption spectrum was measured in the same manner as described above.

Next, the crystals obtained are then washed with acetone and dried to obtain a Bragg angle (2θ ± 0.2 °) of 7.5 °, 9.9 °, 12.5 ° with respect to CuKα characteristic X-rays. Thus, 5.5 parts by mass of hydroxygallium phthalocyanine having diffraction peaks at 16.3 °, 18.6 °, 25.1 °, and 28.3 ° were obtained. The obtained hydroxygallium phthalocyanine pigment had a BET specific surface area of 38.3 m ² / g, a maximum particle size of 1.8 μm, and an average particle size of 0.2 μm. This hydroxygallium phthalocyanine was designated as “hydroxygallium phthalocyanine-2”. The X-ray diffraction spectrum and BET specific surface area were measured in the same manner as described above.

Example 1
First, the surface of an aluminum tube (diameter 30 mm, length 404 mm, wall thickness 1 mm) is roughened by a liquid honing method using alumina spherical fine powder (volume average particle diameter D50v = 30 μm) (centerline average roughness). Ra = 0.18 μm) to prepare a cylindrical aluminum substrate.

  100 parts by mass of zinc oxide (manufactured by Teika, “MZ-300”, average particle diameter 70 nm) and 500 parts by mass of toluene are mixed with stirring, and a silane coupling agent (“KBM603”, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by mass was added and stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure and baked at 150 ° C. for 2 hours.

  60 parts by mass of surface-treated zinc oxide, 15 parts by mass of blocked isocyanate (“Sumijoule 3175”, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent, butyral resin (“BM-1”, manufactured by Sekisui Chemical Co., Ltd.) 15 parts by weight and 85 parts by weight of methyl ethyl ketone are mixed, and then 38 parts by weight of this solution and 25 parts by weight of methyl ethyl ketone are mixed, and dispersed using a 1 mmφ glass bead in a sand mill for 2 hours. A liquid was obtained. As a catalyst, 0.005 part by mass of dioctyltin dilaurate was added to the resulting dispersion to obtain a coating solution for forming an undercoat layer. This coating solution was applied onto an aluminum substrate by a dip coating method, followed by drying and curing at 160 ° C. for 100 minutes to obtain an undercoat layer having a thickness of 20 μm.

  Next, 1 part by mass of the above-obtained “hydroxygallium phthalocyanine-1” is mixed with 1 part by mass of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nihon Unicar) and 100 parts by mass of n-butyl acetate. This was dispersed in a sand mill for 5 hours together with 140 parts by mass of glass beads having an outer diameter of 1 mm to prepare a coating solution for forming a charge generation layer. The obtained coating solution was dip-coated on a conductive support provided with an undercoat layer, and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.25 μm.

  Next, 4 parts by mass of N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1 ′] biphenyl-4,4′-diamine and bisphenol Z polycarbonate resin (viscosity average molecular weight 40 , 000) 6 parts by mass was sufficiently dissolved in 80 parts by mass of chlorobenzene to prepare a charge transport layer coating solution. The obtained coating solution was dip-coated on the charge generation layer and heated at 130 ° C. for 45 minutes to form a charge transport layer having a thickness of 20 μm.

  3 parts by mass of a compound represented by the formula (I-2), 3 parts by mass of a resol type phenolic resin (trade name “Resist Top PL-2211”, manufactured by Gunei Chemical), 0.3 parts by mass of colloidal silica, polyvinylphenol resin ( Aldrich) 0.5 parts by mass and 3,5-di-tert-butyl-4-hydroxytoluene (BHT) 0.4 parts by mass, isopropyl alcohol 5 parts by mass and methyl isobutyl ketone 5 parts by mass In addition to the solvent, a coating solution for forming a protective layer was prepared. This coating solution is applied onto the charge transport layer by a ring-type dip coating method, air-dried at room temperature for 30 minutes, and then heated and cured at 145 ° C. for 48 minutes to form a protective layer having a thickness of 2.8 μm. Thus, an electrophotographic photosensitive member of Example 1 was obtained.

(Example 2)
An electrophotographic photoreceptor of Example 2 was obtained in the same manner as Example 1 except that the compound represented by formula (I-17) was used instead of the compound represented by formula (I-2).

(Example 3)
An electrophotographic photoreceptor of Example 3 was obtained in the same manner as Example 1 except that the compound represented by the formula (II-1) was used instead of the compound represented by the formula (I-2).

Example 4
An electrophotographic photoreceptor of Example 4 was obtained in the same manner as Example 1 except that the compound represented by formula (II-16) was used instead of the compound represented by formula (I-2).

(Example 5)
An electrophotographic photoreceptor of Example 5 was obtained in the same manner as Example 1 except that the compound represented by the formula (IV-3) was used instead of the compound represented by the formula (I-2).

(Example 6)
An electrophotographic photoreceptor of Example 6 was obtained in the same manner as Example 1 except that the compound represented by the formula (IV-24) was used instead of the compound represented by the formula (I-2).

(Example 7)
An electrophotographic photoreceptor of Example 7 was obtained in the same manner as Example 1 except that the compound represented by the formula (V-4) was used instead of the compound represented by the formula (I-2).

(Example 8)
An electrophotographic photoreceptor of Example 8 was obtained in the same manner as Example 1 except that the compound represented by the formula (V-15) was used instead of the compound represented by the formula (I-2).

Example 9
First, the charge transport layer was formed in the same manner as in Example 1. Next, 3 parts by mass of the compound represented by the formula (I-2), 3 parts by mass of a resol type phenolic resin (trade name “Resist Top PL-2211”, manufactured by Gunei Chemical Co., Ltd.), 0.3 parts by mass of colloidal silica, polyvinyl 0.5 parts by mass of phenol resin (manufactured by Aldrich), 0.4 parts by mass of 3,5-di-t-butyl-4-hydroxytoluene (BHT), and 0.01 parts by mass of paratoluenesulfonic acid were added to isopropyl. In addition to a mixed solvent of 5 parts by mass of alcohol and 5 parts by mass of methyl isobutyl ketone, a coating solution for forming a protective layer was prepared. This coating solution is applied onto the charge transport layer by a ring-type dip coating method, air-dried at room temperature for 30 minutes, and then heated and cured at 145 ° C. for 48 minutes to form a protective layer having a thickness of 2.8 μm. Thus, an electrophotographic photosensitive member of Example 9 was obtained.

(Example 10)
An electrophotographic photoreceptor of Example 10 was obtained in the same manner as Example 9 except that the amount of paratoluenesulfonic acid was 0.035 parts by mass.

(Comparative Example 1)
First, the charge transport layer was formed in the same manner as in Example 1. Next, 2 parts by mass of the compound represented by the following formula (CT-1) and 2 parts by mass of the compound represented by the following formula (CP-1) were mixed with 5 parts by mass of isopropyl alcohol, 3 parts by mass of tetrahydrofuran and 0.3 parts of distilled water. Add to 0.05 parts by weight of mixed solvent and mix. Add 0.05 parts by weight of ion exchange resin (Amberlyst 15E, manufactured by Rohm and Haas) to this mixture and stir at room temperature for 24 hours for hydrolysis. Went. In formula (CT-1), -i-Pr represents an isopropyl group.

0.02 parts by mass of aluminum trisacetylacetonate (Al (aqaq) ₃ ) was added to 2 parts by mass of the solution obtained by filtering and separating the ion exchange resin from the hydrolyzed product to obtain a coating solution for forming a protective layer. This coating solution was applied onto the charge transport layer by a ring-type dip coating method and air-dried at room temperature for 10 minutes. Thereafter, the film was cured by heat treatment at 145 ° C. for 48 minutes to form a protective layer having a thickness of 3 μm. Thus, an electrophotographic photoreceptor of Comparative Example 1 was obtained.

(Comparative Example 2)
An electrophotographic photoreceptor of Comparative Example 2 was obtained in the same manner as Example 9 except that the amount of paratoluenesulfonic acid was 0.05 parts by mass.

(Comparative Example 3)
An electrophotographic photoreceptor of Comparative Example 3 was obtained in the same manner as Example 1 except that “hydroxygallium phthalocyanine-2” was used instead of “hydroxygallium phthalocyanine-1”.

<Volume resistivity and volume resistivity ratio>
About the electrophotographic photoreceptors obtained in Examples 1 to 10 and Comparative Examples 1 to 3, the volume resistivity R1 of the white light exposed portion and the volume resistivity R0 of the non-exposed portion of the photosensitive layer were determined according to the following method, and obtained. The volume resistivity ratio (R1 / R0) was determined from the obtained R1 and R0 values. The results obtained are shown in Table 57.

(Measurement of volume resistivity R1 and volume resistivity R0)
White light (fluorescent lamp) having an illuminance of 1000 Lux was irradiated for 10 minutes on a 3 cm ² surface area at the center of the photoreceptor. A 1 cm ² (1 cm × 1 cm) Al electrode is attached to the surface of the exposed portion, and a frequency response analyzer (1260 type, manufactured by Solartron) is used in an environment of a temperature of 22 ° C. and a humidity of 55% RH. The volume resistivity R1 was determined by measuring and averaging the volume resistivity 100 times at an applied voltage of waveform 1V. Further, a 1 cm ² electrode was attached to the surface of the non-exposed portion, and the volume resistivity R0 was obtained under the same conditions as described above.

<Evaluation of image quality>
The photoreceptors of Examples 1 to 10 and Comparative Examples 1 to 3 that were irradiated with white light as described above were mounted as the photoreceptors of a full color printer Docu Print C2220 manufactured by Fuji Xerox Co., Ltd., and the environment was 22 ° C. and 55% RH. Below, 30% halftone image formation was performed on A3 paper, and the image quality at that time was visually evaluated based on the following evaluation criteria. The results obtained are shown in Table 57.
A: No density difference is observed in the image.
B: A very slight density difference is observed between the exposed portion and the non-exposed portion of white light.
C: A density difference is observed between the exposed portion of white light and the non-exposed portion.

<Ghost evaluation>
Images were formed using a full-color printer Docu Print C2220 manufactured by Fuji Xerox Co., Ltd. produced in the same manner as described above, and the presence or absence of initial ghost was visually evaluated according to the following criteria. The results obtained are shown in Table 57.
A: No ghost is seen in the image.
B: A little ghost is seen in the image.
C: A ghost is seen in the image.
In the table, “Negative” indicates that a negative ghost has occurred, and “Positive” indicates that a positive ghost has occurred.

<Measurement of residual potential>
For the electrophotographic photoreceptors obtained in Examples 1 to 10 and Comparative Examples 1 to 3, the residual potential was measured by the following procedure using the evaluation apparatus shown in FIG. The results obtained are shown in Table 57. The evaluation apparatus 400 shown in FIG. 9 can be loaded with a photoconductor 401 to be evaluated. A charger (Scotron charger) 402, an exposure light source (wavelength 780 nm semiconductor laser) 403, a charge eliminating device around the photoconductor. A light source (red LED light source) 404 and a surface potential measurement probe 405 are provided with a frame 406 attached in this order.

Under normal temperature and normal humidity (20 ° C., 40% RH), the photoconductor is rotated at 100 rpm, the photoconductor is charged to −700 V by a scorotron charger, and a semiconductor laser having a wavelength of 780 nm is used 1 second after charging. Irradiate light with 10.0 erg / cm ² to discharge, and then discharge 30.0 seconds after charging with a red LED light of 50.0 erg / cm ² to remove the charge, and the potential V _RP 100 msec after the charge removal Measurement was made with a potential measuring probe, which was defined as a residual potential.

As shown in Table 57, it was confirmed that the density unevenness was sufficiently suppressed in the images formed using the photoreceptors of Examples 1 to 10. Therefore, by designing the photoconductor so that the volume resistivity of the photosensitive layer and the volume resistivity ratio before and after light exposure satisfy the conditions according to the present invention, the photoconductor is exposed to light such as a fluorescent lamp. It was found that the occurrence of image quality defects such as density unevenness can be sufficiently suppressed. Further, from the results of the photoreceptors of Examples 9 and 10, by using the organic sulfonic acid within the range where the volume resistivity ratio of the photosensitive layer and the volume resistivity ratio before and after the light exposure satisfy the conditions according to the present invention, It has been found that the residual potential on the surface of the photoreceptor can be further reduced while sufficiently suppressing the occurrence of density unevenness. It was also confirmed that the photoreceptors of Examples 1 to 10 can sufficiently prevent the occurrence of negative ghosts and positive ghosts.

1 is a schematic cross-sectional view showing a preferred embodiment of an electrophotographic photoreceptor of the present invention. FIG. 6 is a schematic cross-sectional view showing another preferred embodiment of the electrophotographic photosensitive member of the present invention. FIG. 6 is a schematic cross-sectional view showing another preferred embodiment of the electrophotographic photosensitive member of the present invention. 1 is a schematic configuration diagram illustrating a preferred embodiment of an image forming apparatus of the present invention. It is a schematic block diagram which shows other suitable embodiment of the image forming apparatus of this invention. It is a schematic block diagram which shows other suitable embodiment of the image forming apparatus of this invention. It is a schematic block diagram which shows other suitable embodiment of the image forming apparatus of this invention. It is a schematic diagram showing a preferred embodiment of the process cartridge of the present invention. It is a schematic block diagram which shows the structure of the evaluation apparatus for evaluating the residual potential of a photoreceptor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electrophotographic photosensitive member, 2 ... Conductive support body, 3 ... Photosensitive layer, 4 ... Undercoat layer, 5 ... Charge generation layer, 6 ... Charge transport layer, 7 ... Protective layer, 8 ... Single layer type photosensitive layer, 21 ... 22 charging device, 24 ... developing device, 27 ... cleaning device, 30 ... exposure device, 40 ... transfer device, 50 ... intermediate transfer member, 100, 110, 120, 130 ... image forming device, 300 ... process cartridge.

Claims (6)

An electrophotographic photosensitive member having a conductive support, and a photosensitive layer provided on the conductive support and including a protective layer disposed on the side farthest from the conductive support,
The volume resistivity per cm ² of the surface of the photosensitive layer measured under an environment of a temperature of 22 ° C. and a humidity of 55% RH was R0 (Ω · cm), and the photosensitive layer exposed to 1000 Lux white light for 10 minutes. An electrophotographic photoreceptor, wherein the following formulas (1) and (2) are satisfied when the volume resistivity per 1 cm ^{2 of the} surface is R1 (Ω · cm).
3.7 × 10 ¹⁰ Ω · cm ≦ R0 ≦ 8.9 × 10 ¹⁰ Ω · cm (1)
0.1 ≦ (R1 / R0) ≦ 0.71 (2)   The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer contains hydroxygallium phthalocyanine having a maximum peak wavelength in a range of 810 to 839 nm in a spectral absorption spectrum in a wavelength range of 600 to 900 nm.   The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains a phenol resin having a crosslinked structure and having a charge transporting property. The protective layer further comprises an organic sulfonic acid and / or a derivative thereof;
4. The electrophotographic photosensitive member according to claim 3, wherein the content of the organic sulfonic acid and / or derivative thereof is 0.01 to 0.25% by mass based on the total solid content of the protective layer. body. The electrophotographic photosensitive member according to any one of claims 1 to 4,
A charging means for charging the electrophotographic photosensitive member; a developing means for developing a latent electrostatic image formed on the electrophotographic photosensitive member with toner to form a toner image; and At least one selected from the group consisting of cleaning means for removing toner remaining on the surface;
A process cartridge comprising: The electrophotographic photosensitive member according to any one of claims 1 to 4,
Charging means for charging the electrophotographic photosensitive member;
Exposure means for forming an electrostatic latent image on the charged electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image with toner to form a toner image;
Transfer means for transferring the toner image from the electrophotographic photosensitive member to a transfer target;
An image forming apparatus comprising:

Images