JP4591146B2 - Electrophotographic photosensitive member, process cartridge, and image forming apparatus - Google Patents

Description

The present invention, electronic photosensitive member, a process cartridge and an image forming apparatus.

  Electrophotographic technology is widely used not only in the field of conventional copying machines but also in various printers, facsimiles and the like because it can obtain images of immediacy and high quality. As for electrophotographic photoreceptors (hereinafter, simply referred to as “photoreceptors” in some cases) that form the core of electrophotographic technology, inorganic photoconductive materials such as amorphous silicon and arsenic-selenium are currently used. The mainstream is an organic photoreceptor.

  The structure of the organic photoreceptor has changed to a function-separated photoreceptor in which a layer containing a charge generation material (charge generation layer) and a layer containing a charge transport material (charge transport layer) are provided separately. ing. In this method, an electrophotographic photosensitive material having excellent photosensitivity and response characteristics can be obtained by using a substance having a high charge generation efficiency as a charge generation material and combining it with a substance having a high charge transport capability as a charge transport material. The body is expected to be obtained.

  Thus, as part of the development of a photoreceptor that satisfies the above characteristics, studies have been actively conducted on charge transport materials having a high charge transport capability. Among these, compounds having an arylamine structure have been studied because of their high charge transport ability. As such a compound, for example, a triarylamine compound having a benzidine structure is known (see, for example, Patent Documents 1 to 3).

Japanese Patent Publication No.59-9049 Japanese Patent Publication No. 7-1393 Japanese Patent Publication No. 5-16019

  However, with the recent miniaturization and speeding up of copiers and printers, when a higher level of photosensitivity, response characteristics, and durability is required for the photoreceptor, the conventional charge transport materials described above are required. It has become difficult to respond using

  As a method for improving photosensitivity and response characteristics, a method for increasing the content of the charge transport material in the charge transport layer is also conceivable. However, in such a method, the charge transport material may precipitate in the charge transport layer and adversely affect the printing characteristics, and it is often difficult to ensure sufficient durability of the photoreceptor.

The present invention has been made in view of the above circumstances, and is an electrophotographic photosensitive member capable of high- sensitivity and high-speed response and capable of maintaining high image quality even during repeated use, and an image forming apparatus including such an electrophotographic photosensitive member. And it aims at providing a process cartridge.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above problems can be solved by using an arylamine compound having a specific structure as a charge transport material, and completed the present invention. It came to do.

That is, the electrophotographic photosensitive member of the present invention includes a conductive support, an undercoat layer, and 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. And a charge transport layer containing a charge transport material having a structure represented by the following general formula (1) in this order.

In formula (1), Ar ¹ represents a substituted or unsubstituted aromatic group, X ¹ represents a hydrogen atom, a substituted or unsubstituted aromatic group, and R ¹ , R ² , R ³ and R ⁴ are each Independently, it represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 4 carbon atoms.

According to the electrophotographic photosensitive member of the present invention, an electrophotographic photosensitive member capable of high-sensitivity and high-speed response by maintaining such a charge transport material in the photosensitive layer of the photosensitive member and maintaining high image quality even during repeated use. It becomes feasible. Although the reason why the above-described effect can be obtained by the present invention is not necessarily clear, the present inventors infer as follows.

That is, the electrophotographic photoreceptor of the present invention has four methyl groups bonded to the triphenylamine structure and a butadiene skeleton bonded to the triphenylamine structure and extending the conjugated system to the aromatic group Ar ^1. It is considered that both the charge mobility and the chemical stability are improved, and that the glass transition temperature of the photosensitive layer can be sufficiently suppressed from decreasing when the charge transport material is contained in the photosensitive layer. In addition, when the charge transport material is contained in the photosensitive layer, it is presumed that the photosensitive member can maintain excellent electrical characteristics for a long period of time and sufficiently secure the abrasion resistance of the photosensitive layer.

Since the electrophotographic photosensitive member of the present invention contains the charge transport material in the photosensitive layer, it can respond with high sensitivity and high speed, and can maintain high image quality even during repeated use.

  Further, the process cartridge of the present invention comprises developing the electrophotographic photosensitive member of the present invention, a charging means for charging the electrophotographic photosensitive member, and an electrostatic latent image formed on the electrophotographic photosensitive member with toner. And at least one selected from the group consisting of a developing means for forming a toner image and a cleaning means for removing the toner remaining on the surface of the electrophotographic photosensitive member after transfer.

  The image forming apparatus of the present invention also includes the electrophotographic photosensitive member of the present invention, a charging unit for charging the electrophotographic photosensitive member, and an exposing unit for forming an electrostatic latent image on the electrophotographic photosensitive member. And developing means for developing the electrostatic latent image formed on the electrophotographic photosensitive member with toner to form a toner image, and transfer means for transferring the toner image to the transfer target. Features.

  The process cartridge and the image forming apparatus of the present invention are provided with the electrophotographic photosensitive member of the present invention, so that high sensitivity and high speed response are possible, and high image quality can be obtained even in repeated use.

According to the present invention, it is possible to provide an electrophotographic photosensitive member capable of high- sensitivity and high-speed response and maintaining high image quality even during repeated use, and an image forming apparatus and a process cartridge provided with such an electrophotographic photosensitive member.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings as the case may be. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

(Charge transport material)
The charge transport material of this embodiment is a compound having a structure represented by the following general formula (1).

In the above formula (1), Ar ¹ represents a substituted or unsubstituted aromatic group, X ¹ represents a hydrogen atom, a substituted or unsubstituted aromatic group, and R ¹ , R ² , R ³ and R ⁴ are Each independently represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 4 carbon atoms.

Specific examples of Ar ¹ in the general formula (1) include a substituted or unsubstituted aromatic group represented by the following general formula (Ar-1).


In formula (Ar-1), X ² represents a halogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and k1 represents an integer of 0 to 5.

Also, among the groups represented by X ¹ in the general formula (1), a substituted or Specific examples of the unsubstituted aromatic group, for example, aromatic groups represented by the following formula (X-1) Is mentioned.

In formula (X-1), X ³ represents a halogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and k2 represents an integer of 0 to 5.

  Table 1 shows compounds represented by (1-1) to (1-9) as specific examples of the compound having the structure represented by the general formula (1).

  Production examples of the compound having the structure represented by the general formula (1) will be described below.

  First, a benzaldehyde compound represented by the following general formula (R-1) is prepared as an arylamine raw material compound.

Here, R ¹ , R ² , R ³ and R ⁴ have the same meaning as in the general formula (1).

  The benzaldehyde compound can be synthesized, for example, by heating and stirring the corresponding triphenylamine and phosphorus oxychloride in dimethylformamide at a temperature of 60 ° C. The benzaldehyde compound may be obtained by synthesis by other known methods.

Then mixed with benzaldehyde compound represented by the prepared above general formula (R-1), and a salt is Ru represented by the following general formula (R-2), a known method, for example, tetrahydrofuran, sodium methylate The target compound represented by the general formula (1) can be obtained by heating and stirring in the presence.

Here, Ar ¹ and X ¹ are synonymous with those in the general formula (1). X ⁻ represents Cl ⁻ or Br ⁻ .

  The heating temperature can be 20 to 60 ° C., and the reaction time can be 3 to 8 hours.

  After completion of the reaction, the obtained compound of the general formula (1) can be purified by a known method. For example, after extracting the reaction product with a predetermined organic solvent, the extract can be concentrated and purified by column chromatography. Examples of the organic solvent used for extraction include toluene, ligroin, toluene / hexane mixed solvent, and the like.

(Electrophotographic photoreceptor)
FIG. 1A is a schematic cross-sectional view showing a first embodiment as a reference example of the electrophotographic photosensitive member of the present invention. An electrophotographic photoreceptor 100 shown in FIG. 1A is a laminated type in which functions are separated into a layer containing a charge generation material (charge generation layer 1) and a layer containing a charge transport material (charge transport layer 2). It has a photosensitive layer 6 and has a structure in which a charge generation layer 1 and a charge transport layer 2 are sequentially laminated on a conductive support 3. The charge transport material having the structure represented by the general formula (1) (hereinafter sometimes referred to as “ charge transport material of the present invention ”) is contained in the charge transport layer 2 as a charge transport material.

  Hereinafter, each component of the electrophotographic photoreceptor 100 will be described in detail.

  Examples of the conductive support 3 include those made of metal such as aluminum, copper, iron, zinc and nickel; on a substrate such as a polymer sheet, paper, plastic and glass, aluminum, copper, gold, silver and platinum Conductive treatment by depositing a metal such as palladium, titanium, nickel-chromium, stainless steel, copper-indium; Conductive treatment by depositing a conductive metal compound such as indium oxide or tin oxide on the substrate. Conductive treatment by laminating a metal foil on the substrate; carbon black, indium oxide, tin oxide-antimony oxide powder, metal powder, copper iodide, etc. are dispersed in a binder resin, The thing etc. which carried out the conductive process by apply | coating to are mentioned. The shape of the conductive support 3 may be any of a drum shape, a sheet shape, and a plate shape.

  When a metal pipe substrate is used as the conductive support 3, the surface thereof may remain as it is, but in advance, mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, wet honing, coloring treatment It is preferable to roughen the substrate surface by a surface treatment such as In this way, by roughening the surface of the substrate, it is possible to prevent grain-like density spots due to interference light in the photoconductor that may occur when a coherent light source such as a laser beam is used.

  The charge generation layer 1 contains a charge generation material and a binder resin.

  As the charge generation material, an azo pigment, a perylene pigment, a condensed aromatic pigment, or the like can be used, but a metal-containing or metal-free phthalocyanine is preferably used. Among these, it is particularly preferable to use a hydroxygallium phthalocyanine pigment, a chlorogallium phthalocyanine pigment, a dichlorotin phthalocyanine pigment, or an oxytitanyl phthalocyanine pigment.

In the present embodiment, the optical absorption spectrum in a wavelength range of 600 to 900 nm, Ru using at least a hydroxygallium phthalocyanine pigment having a maximum peak wavelength in the range of 810～839Nm. Such hydroxygallium phthalocyanine pigments are different from conventional V-type hydroxygallium phthalocyanine pigments. Further, those having a maximum peak wavelength in the range of 810 to 835 nm are particularly preferred because more excellent dispersibility can be obtained. Thus, by shifting the maximum peak wavelength of the spectral absorption spectrum to the 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 preferably has an average particle diameter in a specific range and a BET specific surface area in a specific range. Specifically, the average particle size is preferably 0.20 μm or less, more preferably 0.01 to 0.15 μm, still more preferably 0.01 to 0.1 μm, and It is particularly preferably 01 to 0.08 μm, and the BET specific surface area is preferably 45 m ² / g or more, more preferably 50 m ² / g or more, and 55 to 120 m ² / g. It is particularly preferred. 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.

  Furthermore, it is preferable that the hydroxygallium phthalocyanine pigment does not contain coarse particles having a large particle size. Specifically, the above hydroxygallium phthalocyanine pigment preferably has a maximum primary particle size of 0.3 μm or less, and more preferably 0.2 μm or less. When the maximum primary particle diameter exceeds 0.3 μm, the particles are coarse or an aggregate of particles is formed, and the dispersibility when used as a material for an electrophotographic photosensitive member, Defects tend to be likely to occur in characteristics such as sensitivity, chargeability, and dark decay characteristics, thereby tending to cause image quality defects.

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

  The hydroxygallium phthalocyanine pigment may be subjected to a surface treatment from the viewpoint of improving dispersibility as long as the maximum peak wavelength is maintained so as to satisfy the above conditions. Although it does not specifically limit as a surface treating agent, For example, a coupling agent etc. can be used.

  Examples of the coupling agent include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and γ-glycidoxypropyltrimethoxy. Silane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ -Aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3 -Methacryloxypro Rutrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (Aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, etc. A silane coupling agent is mentioned. 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- Aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane are preferred.

  In addition to coupling agents, zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate Organic zirconium compounds such as zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like can be used. Further, tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium lactate, titanium lactate Organic titanium compounds such as ethyl ester, titanium triethanolamate, polyhydroxy titanium stearate, aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) An organoaluminum compound such as can be used.

  In the above-described spectral absorption spectrum in the wavelength range of 600 to 900 nm, the hydroxygallium phthalocyanine pigment having the maximum peak wavelength in the range of 810 to 839 nm can be obtained by the following production method.

  That is, in the X-ray diffraction spectrum using CuKα characteristic X-rays, the manufacturing method is Bragg angle (2θ ± 0.2 °) 6.9 °, 13.2 to 14.2 °, 16.5 °, 26. By wet grinding a hydroxygallium phthalocyanine pigment having diffraction peaks at 0 ° and 26.4 °, or 7.0 °, 13.4 °, 16.6 °, 26.0 ° and 26.7 °. In the method for producing a hydroxygallium phthalocyanine pigment to be crystallized, the wet pulverization treatment is carried out using a pulverizer using a spherical medium having an outer diameter of 0.1 to 3.0 mm, and the amount of media used is changed to hydroxygallium phthalocyanine pigment 1 The wet pulverization treatment time is determined by measuring the absorption wavelength of the hydroxygallium phthalocyanine pigment in the pulverization process. In the wet pulverization treatment, the crystallization of the hydroxygallium phthalocyanine pigment after the wet pulverization treatment has 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. It is preferable to determine the wet grinding time while monitoring the conversion state by measuring the absorption wavelength of the wet grinding liquid.

  In an X-ray diffraction spectrum using CuKα characteristic X-rays used as a raw material in such a production method, Bragg angles (2θ ± 0.2 °) of 6.9 °, 13.2-14.2 °, 16.5 A hydroxygallium phthalocyanine pigment having diffraction peaks at °, 26.0 ° and 26.4 °, or 7.0 °, 13.4 °, 16.6 °, 26.0 ° and 26.7 ° "Type I hydroxygallium phthalocyanine pigment") can be obtained by a conventionally known method. An example is shown below.

  First, a method in which o-phthalodinitrile or 1,3-diiminoisoindoline and gallium trichloride are reacted in a predetermined solvent (type I chlorogallium phthalocyanine method); o-phthalodinitrile, alkoxygallium and ethylene glycol Crude gallium phthalocyanine is produced by a method of synthesizing a phthalocyanine dimer (phthalocyanine dimer) by reacting with heating in a predetermined solvent (phthalocyanine dimer method). As the solvent in the above reaction, α-chloronaphthalene, β-chloronaphthalene, α-methylnaphthalene, methoxynaphthalene, dimethylaminoethanol, diphenylethane, ethylene glycol, dialkyl ether, quinoline, sulfolane, dichlorobenzene, dimethylformamide, dimethyl It is preferable to use an inert and high boiling point solvent such as sulfoxide or dimethylsulfamide.

  Next, the crude gallium phthalocyanine obtained in the above step is subjected to an acid pasting process, whereby the crude gallium phthalocyanine is made into fine particles and converted into an I-type hydroxygallium phthalocyanine pigment. Here, the acid pasting treatment, specifically, a solution obtained by dissolving crude gallium phthalocyanine in an acid such as sulfuric acid or an acid salt such as a sulfate, is poured into an aqueous alkaline solution, water or ice water, Recrystallized. As the acid used for the acid pasting treatment, sulfuric acid is preferable, and sulfuric acid having a concentration of 70 to 100% (particularly preferably 95 to 100%) is more preferable.

  In the spectral absorption spectrum in the wavelength range of 600 to 900 nm, the hydroxygallium phthalocyanine pigment having the maximum peak wavelength in the range of 810 to 839 nm is a wet type of the I-type hydroxygallium phthalocyanine pigment obtained by the acid pasting process together with a solvent. It can be obtained by pulverization and crystal conversion.

  Here, the wet pulverization treatment is performed using a pulverizer using a spherical medium having an outer diameter of 0.1 to 3.0 mm, preferably a spherical medium having an outer diameter of 0.2 to 2.5 mm. Done with. When the outer shape of the media is larger than 3.0 mm, the pulverization efficiency is lowered, so that the particle diameter does not become small and aggregates tend to be easily generated. Further, when the outer diameter of the medium is smaller than 0.1 mm, it tends to be difficult to separate the medium and the hydroxygallium phthalocyanine pigment. In addition, when the media is not spherical, but in other shapes such as a columnar shape or an indefinite shape, the grinding efficiency is reduced and the media is easily worn by grinding, so that the wear powder becomes an impurity and deteriorates the characteristics of the hydroxygallium phthalocyanine pigment. There is a tendency to make it easy.

  The material of the media is not particularly limited, but is preferably one that hardly causes image quality defects even when mixed in a hydroxygallium phthalocyanine pigment, and glass, zirconia, alumina, meno and the like are preferable.

  Further, the material of the container for performing the wet pulverization treatment is not particularly limited, but it is preferable that it does not easily cause image quality defects when mixed in a hydroxygallium phthalocyanine pigment, and glass, zirconia, alumina, meno, polypropylene, poly Tetrafluoroethylene, polyphenylene sulfide and the like are preferable. Alternatively, the inner surface of a metal container such as iron or stainless steel may be lined with glass, polypropylene, polytetrafluoroethylene, polyphenylene sulfide, or the like.

  The amount of the media used varies depending on the apparatus used, but is 50 parts by mass or more, preferably 55 to 100 parts by mass with respect to 1 part by mass of the type I hydroxygallium phthalocyanine pigment. Also, as the media outer diameter decreases, the media density in the device increases even with the same weight (use amount), and the viscosity of the mixed solution increases and the pulverization efficiency changes. It is desirable to perform wet processing at an optimal mixing ratio by controlling the amount of media used and the amount of solvent used.

  In the above-described method for producing a hydroxygallium phthalocyanine pigment, the maximum values of the average particle diameter, the BET specific surface area and the primary particle diameter of the resulting hydroxygallium phthalocyanine pigment are controlled by appropriately adjusting the conditions of these wet pulverization treatments. be able to.

  Moreover, the temperature of the wet pulverization treatment is preferably 0 to 100 ° C, more preferably 5 to 80 ° C, and particularly preferably 10 to 50 ° C. When the temperature is low, the rate of crystal transition tends to be slow, and when the temperature is too high, the solubility of the hydroxygallium phthalocyanine pigment tends to be high and crystal growth tends to be difficult. is there.

  Examples of the solvent used in the wet grinding treatment include amides such as N, N-dimethylformamide, N, N-dimethylacetamide, and N-methylpyrrolidone; esters such as ethyl acetate, n-butyl acetate, and iso-amyl acetate. In addition to ketones such as acetone, methyl ethyl ketone, methyl iso-butyl ketone, dimethyl sulfoxide and the like. The usage-amount of these solvents is 1-200 mass parts normally with respect to 1 mass part of hydroxygallium phthalocyanine pigments, Preferably it is 1-100 mass parts.

  As an apparatus used for the wet pulverization treatment, an apparatus using a media such as a vibration mill, an automatic mortar, a sand mill, a dyno mill, a coball mill, an attritor, a planetary ball mill, or a ball mill as a dispersion medium can be used.

  In the above-described method for producing a hydroxygallium phthalocyanine pigment, the progress speed of crystal conversion is greatly influenced by the scale of the wet pulverization process, the stirring speed, the media material, etc., but the hydroxygallium phthalocyanine pigment after the wet pulverization process is 600. The wet pulverization treatment time is determined while monitoring the crystal conversion state by measuring the absorption wavelength of the wet pulverization treatment liquid so as to have the maximum peak wavelength in the range of 810 to 839 nm in the spectral absorption spectrum in the wavelength region of ˜900 nm, It is preferable to continue until the crystal is converted into a hydroxygallium phthalocyanine pigment. Here, as a method for monitoring the crystal conversion state by measuring the absorption wavelength of the wet pulverization treatment liquid, for example, a small amount of the pigment solution during the crystal conversion treatment is sampled from the wet pulverization treatment apparatus, and acetone, ethyl acetate, etc. The method of measuring the solution diluted with the solvent by the liquid cell method using a spectrophotometer is mentioned.

  The wet pulverization time thus determined is usually in the range of 5 to 500 hours, preferably in the range of 7 to 300 hours. When the treatment time is less than 5 hours, the crystal conversion is not completed, and the electrophotographic characteristics are deteriorated, and particularly, the sensitivity is apt to be insufficient. Further, when the processing time exceeds 500 hours, sensitivity tends to decrease due to the influence of pulverization stress, productivity decreases, and media wear powder tends to be mixed. By determining the wet pulverization time as described above, it is possible to complete the wet pulverization process in a state where the hydroxygallium phthalocyanine pigment particles are uniformly finely divided, and furthermore, a plurality of lots of repeated wet pulverization processes were performed. In this case, it is possible to suppress the quality variation between lots.

  In the above-described method for producing a hydroxygallium phthalocyanine pigment, it is preferable to perform washing with a solvent and / or heat drying after the wet pulverization treatment. The impurity concentration of the hydroxygallium phthalocyanine pigment can be controlled by such washing with a solvent or heat drying, and in particular, the thermal weight loss rate when the temperature is raised from 25 ° C. to 400 ° C. is 2.0-4. A hydroxygallium phthalocyanine pigment of 0% can be obtained efficiently and reliably.

  When the impurity concentration is controlled by washing with a solvent, examples of the solvent used include water, ethanol, methanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, and ethyl acetate. , Organic solvents such as n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, benzene, toluene, xylene, chlorobenzene, dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, and mixed solvents thereof, and carbon dioxide And supercritical fluids such as nitrogen and the like. As a cleaning method, a known method can be used without any particular limitation. From the viewpoint of cleaning efficiency, a ceramic filter, an ultrasonic cleaner, a Soxhlet extractor, a micromixer having a channel diameter of 10 to 1000 μm, or the like The cleaning method using the is effective.

  Moreover, when controlling an impurity density | concentration by heat drying, as temperature of heat drying, Preferably it is 50-200 degreeC, More preferably, it is 100-180 degreeC. When the heating temperature is less than 50 ° C., it tends to be difficult to completely remove impurities affecting various properties of the hydroxygallium phthalocyanine pigment. When the heating temperature exceeds 200 ° C., the sensitivity of the hydroxygallium phthalocyanine pigment is remarkably increased. It tends to decrease. The heat drying treatment time is preferably adjusted as appropriate according to the weight of the hydroxygallium phthalocyanine pigment to be treated.

  In order to efficiently remove the residual solvent and low boiling point impurities of the hydroxygallium phthalocyanine pigment by heat drying, it is preferable to heat and dry the hydroxygallium phthalocyanine under reduced pressure. When performing heat drying under reduced pressure, there is an advantage that the temperature of heat drying can be made lower than when performing under normal pressure. The temperature of the heat drying at this time is preferably in the range of 50 ° C. to 200 ° C., although it depends on the degree of reduced pressure.

  Heat drying can also be performed in the presence of an inert gas. Examples of the inert gas include nitrogen and helium, neon, argon, etc. belonging to Group 0 of the periodic table, and these can be used alone or in admixture of two or more. By performing heat drying in the presence of these inert gases, there is an advantage that the hydroxygallium phthalocyanine pigment is prevented from being oxidized by oxygen in the air, and heat drying at high temperatures becomes possible. Moreover, it is also preferable to perform heat drying in the state which interrupted light. Thereby, it is possible to prevent the hydroxygallium phthalocyanine pigment from being light fatigued during the heat drying.

  Examples of the binder resin include polycarbonate, polyarylate, polystyrene, polysulfone, polyester, polyimide, polyamide, polyester carbonate, polyvinyl butyral, methacrylate ester polymer, vinyl acetate homopolymer or copolymer, cellulose ester, cellulose ether, Insulating resins such as polybutadiene, polyurethane, phenoxy resin, epoxy resin, silicone resin, fluorine resin, polyvinyl acetal resin, acrylic resin, polyacrylamide resin, polyvinyl pyridine resin, polyvinyl pyrrolidone resin, and partially crosslinked cured products thereof, -N-vinyl carbazole, polyvinyl anthracene, polyvinyl pyrene, polysilane and other photoconductive resins may be mentioned, and one of these may be used alone or 2 It can be used in combination of at least.

  The compounding ratio (weight ratio) of the charge generation material and the binder resin in the charge generation layer 1 is preferably 10: 1 to 1:10, more preferably 8: 2 to 2: 8. If the blending amount of the charge generating material exceeds 10 times the blending amount of the binder resin, the dispersibility of the pigment in the dispersion used in the electrophotographic photoreceptor manufacturing process tends to be insufficient, If the blending amount of the binder resin is less than 1/10, the sensitivity of the electrophotographic photosensitive member tends to be insufficient.

  Furthermore, various additives can be added to the charge generation layer 1 in order to improve electrical characteristics, image quality, and the like. Examples of the additive include quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone. Fluorenone compounds such as 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4 -Oxadiazole compounds such as oxadiazole, 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole, xanthone compounds, thiophene compounds, 3,3 ', 5,5' -Electron transporting substances such as diphenoquinone compounds such as tetra-t-butyldiphenoquinone, electron transporting pigments such as polycyclic condensation systems and azo systems, zirconium crystal Compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, silane coupling agents.

  Here, as a silane coupling agent, the thing similar to what was demonstrated previously can be used.

  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.

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

  When another layer such as the charge transport layer 2 is further formed on the charge generation layer 1, the charge generation layer 1 is not dissolved or swollen by the solvent used in the coating solution. The combination of the binder resin of the charge generation layer 1 and the solvent of the coating solution applied onto the charge generation layer 1 is preferably selected as appropriate. The binder resin of the charge generation layer 1 and the binder resin of the charge transport layer 2, which will be described later, are preferably used in combination with each other having a refractive index close to each other. The difference is preferably 1 or less. When a binder resin having a similar refractive index is used in combination, light reflection at the interface between the charge generation layer 1 and the charge transport layer 2 is suppressed, and the interference fringe prevention effect tends to be improved.

  The charge generation layer 1 is formed by adding a charge generation material and a binder resin to a predetermined solvent, such as 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 homogenizer, and a microfluidizer. , Blade coating method, wire bar coating method, spray coating method, dip coating method, bead coating method, air knife coating It can be obtained by applying by a method, a curtain coating method or the like and drying. Here, as a solvent used for the coating liquid of the charge generation layer 1, specifically, methanol, ethanol, n-butanol, benzyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl 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. Good. The film thickness of the charge generation layer 1 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. When the film thickness of the charge generation layer 1 is less than 0.05 μm, the sensitivity tends to decrease, and when the film thickness exceeds 5 μm, there is a tendency that adverse effects such as poor chargeability tend to occur.

  The charge transport layer 2 contains the charge transport material of the present invention and a binder resin.

  As the binder resin used for the charge transport layer 2, a known resin can be used without any particular limitation, but a resin capable of forming an electrically insulating film is preferably used. For example, polycarbonate resin, polyarylate resin, polyester 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-carbazole, polyvinyl butyral, polyvinyl formal, polysulfone, casein, gelatin, polyvinyl alcohol, ethyl cellulose, phenol resin, polyamide, carboxy-methyl cellulose, vinylidene chloride System polymer wax, polyurethane and the like. These binder resins can be used alone or in combination of two or more. In particular, a polycarbonate resin, a polyarylate resin, a polyester resin, a methacrylic resin, and an acrylic resin are preferably used because they are excellent in compatibility with a charge transport material, solubility in a solvent, and strength.

  The charge transport layer 2 may contain other charge transport materials other than the charge transport material of the present invention. Examples of other charge transporting materials include oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1 -[Pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline and other pyrazoline derivatives, triphenylamine, tri (P-methyl) phenylamine, N, N'- Aromatic tertiary amino compounds such as bis (3,4-dimethylphenyl) biphenyl-4-amine, dibenzylaniline, 9,9-dimethyl-N, N′-di (p-tolyl) fluoren-2-amine Aromatic tertiary diamination such as N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1-biphenyl] -4,4′-diamine , 1,2,4-triazine derivatives such as 3- (4′dimethylaminophenyl) -5,6-di- (4′-methoxyphenyl) -1,2,4-triazine, 4-diethylaminobenzaldehyde-1 , 1-diphenylhydrazone, 4-diphenylaminobenzaldehyde-1,1-diphenylhydrazone, hydrazone derivatives such as [p- (diethylamino) phenyl] (1-naphthyl) phenylhydrazone, 2-phenyl-4-styryl-quinazoline, etc. Quinazoline derivatives, benzofuran derivatives such as 6-hydroxy-2,3-di (p-methoxyphenyl) -benzofuran, α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N′-diphenylaniline, Enamine derivatives, carbazole derivatives such as N-ethylcarbazole, poly- Hole transport materials such as N-vinylcarbazole and its derivatives, quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2,4,5,7 -Fluorenone compounds such as tetranitro-9-fluorenone, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) Oxadiazole compounds such as -1,3,4-oxadiazole, 2,5-bis (4-diethylaminophenyl) 1,3,4 oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, And electron transport materials such as diphenoquinone compounds such as 5,5 ′ tetra-t-butyldiphenoquinone. Furthermore, as another charge transport material, a polymer having the basic structure of the compound exemplified above in the main chain or side chain can be used. These charge transport materials can be used singly or in combination of two or more.

  Further, the blending ratio (weight ratio) between the charge transporting material and the binder resin of the present invention can be arbitrarily set in consideration of a decrease in electrical characteristics and a decrease in film strength, but preferably 10: 1 to 1:10. And more preferably 5: 1 to 1: 5. When the blending amount of the charge transport material of the present invention exceeds 10 times the blending amount of the binder resin, the charge transporting material is deposited or formed in the coating liquid used in the manufacturing process of the electrophotographic photosensitive member. The charge transport material is likely to be deposited in the transport layer, and if the deposition occurs, it may cause image quality defects. On the other hand, if the blending amount of the binder resin is less than 1/10, the photosensitivity of the electrophotographic photosensitive member tends to be insufficient.

  Furthermore, the thickness of the charge transport layer 2 is preferably 5 to 100 μm, more preferably 5 to 50 μm, and particularly preferably 5 to 35 μm.

  In addition, a solid lubricant or a metal oxide can be dispersed in the charge transport layer 2 for the purpose of reducing wear. Solid lubricants include fluorine-containing resin particles (ethylene tetrafluoride, ethylene trifluoride chloride, ethylene tetrafluoride hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride, and those And the like, and silicon-containing resin particles. Examples of the metal oxide include silica, alumina, titanium oxide, tin oxide and the like.

  When the solid lubricant is dispersed in the charge transport layer 2, the friction coefficient on the surface of the charge transport layer 2 decreases, so that wear can be suppressed. Further, when the metal oxide is dispersed, the mechanical hardness of the charge transport layer 2 is increased, so that wear can be suppressed. Further, since the fluorine-containing resin particles are hardly dispersed particles, dispersibility is improved when a fluorine-containing polymer-based dispersion aid is used.

  As a method for dispersing the solid lubricant or metal oxide in the charge transport layer 2, a method such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, a paint shaker, a homogenizer, or a high-pressure treatment type homogenizer is used. be able to. In this dispersion, it is effective to make the dispersed particles 1.0 μm or less, preferably 0.2 μm or less.

  Further, a small amount of silicone oil can be added to the charge transport layer 2 as a leveling agent for improving the smoothness of the coating film.

  As a solvent used for the coating liquid for forming the charge transport layer 2, a common organic solvent such as dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, toluene and the like can be used alone or in combination. As a method for applying the charge transport layer 2, a normal method 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, or a curtain coating method can be used.

  Further, in the photosensitive layer 6 (the charge generation layer 1, the charge transport layer 2, etc.), it is possible to prevent the photoreceptor from being deteriorated by ozone, an oxidizing gas, or light or heat generated in the image forming apparatus. Thus, additives such as antioxidants and light stabilizers can be added.

  Here, 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 hindered phenol antioxidants include 2,6-di-t-butyl-4-methylphenol, styrenated phenol, n-octadecyl-3- (3 ′, 5′-di-t-butyl-4 ′. -Hydroxyphenyl) -propionate, 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2-t-butyl-6- (3'-t-butyl-5'-methyl-2) '-Hydroxybenzyl) -4-methylphenyl acrylate, 4,4'-butylidene-bis- (3-methyl-6-tert-butylphenol), 4,4'-thio-bis- (3-methyl-6-t -Butylphenol), 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, tetrakis- [methylene-3- (3 ', 5',-di- -Butyl-4'-hydroxyphenyl) propionate] methane, 3,9-bis [2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl ] -2,4,8,10-tetraoxaspiro [5,5] undecane and the like.

  Examples of hindered amine antioxidants include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [ 2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy ] -2,2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4 -Dione, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpi-succinate Lysine polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diimyl} {(2,2,6,6-tetra Methyl-4-piperidyl) imino} hexamethylene {(2,3,6,6-tetramethyl-4-piperidyl) imino}], 2- (3,5-di-t-butyl-4-hydroxybenzyl)- 2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl- N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate and the like.

  Examples of organic sulfur-based antioxidants include dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythritol-tetrakis. -(Β-laurylthiopropionate), ditridecyl-3,3′-thiodipropionate, 2-mercaptobenzimidazole and the like.

  Examples of the organophosphorus antioxidant include trisnonylphenyl phosfte, triphenyl phosfte, tris (2,4-di-t-butylphenyl) -phosfte, and the like.

  These organic sulfur-based antioxidants and organic phosphorus-based antioxidants are referred to as secondary antioxidants, and a synergistic effect can be obtained by using them together with primary antioxidants such as phenols or amines. .

  Examples of the light stabilizer include benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine derivatives.

  Here, examples of the benzophenone light stabilizer include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, and the like.

  Examples of the benzotriazole light stabilizer include 2- (2′-hydroxy-5′-methylphenyl) -benzotriazole, 2- [2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ′, 6 ″). -Tetrahydrophthalimido-methyl) -5'-methylphenyl] benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'- Hydroxy-3′-t-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5 ′,-di-t-butylphenyl) benzotriazole, 2- ( 2'-hydroxy-5'-t-octylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5',-di-t-amylphenyl) benzotriazole And the like.

  In addition, 2,4-di-t-butylphenyl-3 ', 5'-di-t-butyl-4'-hydroxybenzoate, nickel dibutyl-dithiocarbamate, or the like may be used.

Further, for the purpose of improving sensitivity, reducing residual potential, and reducing fatigue during repeated use, the photosensitive layer 6 (charge generation layer 1, charge transport layer 2, etc.) contains at least one electron accepting substance. be able to. Examples of the electron accepting substance include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-di Examples include nitrobenzene, chloranilquinone, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, phthalic acid and the like. Among these, fluorenone compounds, quinone compounds and, Cl-, CN-, NO 2 _- benzene derivatives having an electron attractive substituent, and the like are particularly preferable.

  FIG. 1B is a schematic cross-sectional view showing a second embodiment of the electrophotographic photosensitive member of the present invention. The electrophotographic photoreceptor 110 shown in FIG. 1B is similar to the electrophotographic photoreceptor 100 shown in FIG. 1A except that the undercoat layer 4 is provided between the conductive support 3 and the photosensitive layer 6. It has the same structure.

  The undercoat layer 4 is made of a material arbitrarily selected from a binder resin, an organic or inorganic powder, an electron transporting substance, and the like. Here, as the binder resin, acetal resin such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin , Vinyl chloride-vinyl acetate-maleic anhydride resin, 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 Known materials such as organic titanium compounds and silane coupling agents can be used. These compounds can be used alone, as a mixture of a plurality of compounds, or as a polycondensate.

  Here, as the silane coupling agent, the zirconium chelate compound, the titanium chelate compound and the aluminum chelate compound, the same ones as described above can be used.

  In the undercoat layer 4, fine powders of various inorganic compounds can be added for the purpose of improving electrical characteristics and light scattering properties. In particular, white pigments such as titanium oxide, zinc oxide, tin oxide, zinc white, zinc sulfide, lead white, and lithopone, and inorganic pigments as extender pigments such as alumina, calcium carbonate, and barium sulfate are effective. The added fine powder has a particle size of 0.01 to 2 μm. The fine powder is added as necessary, but the addition amount is preferably 10 to 90% by mass, more preferably 30 to 80% by mass based on the total amount of the solid content of the undercoat layer 4. .

  Among these fine powders, metal oxide fine particles such as titanium oxide, zinc oxide and tin oxide are preferably added to the undercoat layer 4. By adding such metal oxide fine particles, there is a tendency that the characteristics of the electrophotographic photoreceptor can be improved.

The average primary particle size of the metal oxide fine particles is preferably 0.5 μm or less. Moreover, it is preferable that the undercoat layer 4 obtains an appropriate resistance for obtaining leak resistance. Therefore, as the metal oxide fine particles, those having a powder resistance of about 10 ² to 10 ¹¹ Ω · cm are used. Is preferred. If the specific resistance of the metal oxide fine particles is less than 10 ² Ω · cm, sufficient leak resistance tends to be not obtained, and if it exceeds 10 ¹¹ Ω · cm, there is a tendency to cause an increase in residual potential. Moreover, 2 or more types of metal oxide fine particles can be mixed and used.

  The metal oxide fine particles can also be subjected to a surface treatment. When surface-treating the metal oxide fine particles, for example, a hydrolyzable organometallic compound can be used. The hydrolyzable organometallic compound is not particularly limited as long as the desired photoreceptor characteristics can be obtained. For example, a zirconium chelate compound, a titanium chelate compound, an aluminum chelate compound, a titanium alkoxide compound, an organic titanium compound, a silane cup Known materials such as a ring agent can be used. Here, as the silane coupling agent, the zirconium chelate compound, the titanium chelate compound and the aluminum chelate compound, the same ones as described above can be used.

  As the surface treatment method for the metal oxide fine particles, any known method can be used, and a dry method or a wet method can be used. When surface treatment is performed by a dry method, a hydrolyzable organometallic compound dissolved in an organic solvent or water is dropped while stirring the metal oxide fine particles with a mixer having a large shearing force, etc. It is uniformly treated by spraying with nitrogen gas. The addition or spraying is preferably performed at a temperature below the boiling point of the solvent. When sprayed at a temperature equal to or higher than the boiling point of the solvent, the solvent evaporates before being uniformly stirred, and the hydrolyzable organometallic compound tends to locally accumulate, making uniform treatment difficult. Moreover, after addition or spraying, 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 dry method, the surface adsorbed water can be removed by heating and drying the metal oxide fine particles before the surface treatment with the hydrolyzable organometallic compound. By removing the surface adsorbed water before the treatment, the hydrolyzable organometallic compound can be uniformly adsorbed on the surface of the metal oxide fine particles. The metal oxide fine particles can be heat-dried while stirring with a mixer having a large shearing force.

  When surface treatment is performed by a wet method, the metal oxide fine particles are dispersed in a solvent using ultrasonic waves, a sand mill, an attritor, a ball mill, etc., and a hydrolyzable organometallic compound solution is added and stirred or dispersed. Then, it is processed uniformly by removing the solvent. The removal of the solvent is performed, for example, by distilling off by distillation. In the removal method by filtration, unreacted hydrolyzable organometallic compounds tend to flow out, and the amount of hydrolyzable organometallic compounds 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. Also in the wet method, the surface adsorbed water can be removed before the metal oxide fine particles are surface-treated with the hydrolyzable organometallic compound. As this surface adsorbed water removal method, in addition to the removal by heating and drying as in the dry method, a method of removing with stirring and heating in the solvent used for the surface treatment, a method of removing by azeotropy with the solvent, etc. are used. Can do. In addition, the quantity of the hydrolyzable organometallic compound with respect to metal oxide microparticles | fine-particles can be arbitrarily set in the range which can obtain a desired electrical property.

  In addition, it is also effective in the undercoat layer 4 to contain the electron transporting substance, the electron transporting pigment and the like described above from the viewpoint of lowering the residual potential and environmental stability. Examples of the electron transporting pigment to be contained in the undercoat layer 4 include organic pigments such as perylene pigments, bisbenzimidazole perylene pigments, polycyclic quinone pigments, indigo pigments, quinacridone pigments, cyano groups, nitro groups, nitroso groups, Examples thereof include organic pigments such as bisazo pigments and phthalocyanine pigments having electron-withdrawing substituents such as halogen atoms, and inorganic pigments such as zinc oxide and titanium oxide. Among these pigments, perylene pigments, bisbenzimidazole perylene pigments and polycyclic quinone pigments are preferable because of their high electron mobility. If the amount of the electron transport pigment is too large, the strength of the undercoat layer 4 tends to decrease and coating film defects tend to occur. Therefore, it is preferably 95% by mass or less based on the total solid content of the undercoat layer 4. Is added so that it may become 90 mass% or less.

  Furthermore, the thickness of the undercoat layer 4 is preferably 0.01 to 30 μm, and more preferably 0.05 to 25 μm. When the undercoat layer 4 does not contain the metal oxide fine particles described above, the thickness of the undercoat layer 4 is more preferably 0.1 to 10 μm, and particularly preferably 0.5 to 5.0 μm. preferable. On the other hand, when the undercoat layer 4 contains metal oxide fine particles, the thickness of the undercoat layer 4 is preferably 15 μm or more, and more preferably 15 to 50 μm. If the thickness of the undercoat layer 4 satisfies the above conditions, local dielectric breakdown (photoreceptor leakage) in the electrophotographic photoreceptor 110 tends to be more reliably prevented. Further, there is a tendency that stable image quality can be obtained over a longer period. The undercoat layer 4 preferably has a Vickers strength of 35 or more.

  Furthermore, fine particles other than the metal oxide fine particles can be further added to the undercoat layer 4. As these fine particles, various resin fine particles such as silicone fine particles and polytetrafluoroethylene fine particle crosslinked PMMA resin particles can be used. The amount and particle size of the resin fine particles contained in the undercoat layer 4 can be arbitrarily set within a range where desired surface roughness and electrical characteristics can be obtained, but are preferably 0.5 to 10 μm, and more preferably 1 to 6 μm. In addition, two or more types of resin particles having different particle diameters can be mixed and used.

  Further, the undercoat layer 4 can be polished to adjust the surface roughness. As a polishing method, buffing, sand blasting, wet honing, grinding, or the like can be used.

  In addition, when preparing a coating liquid for forming the undercoat layer 4, when adding a fine powder substance, it is added to a solution in which the resin component is dissolved and dispersed. As the dispersion treatment method, methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, a dyno mill, and a paint shaker can be used.

  Here, as a solvent used in preparing the coating solution, the resin component can be dissolved, and when an electron transporting pigment is added, gelation or aggregation does not occur when the pigment is mixed or dispersed. If it is a thing, it will not restrict | limit in particular. Specific examples of such solvents include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, and n-acetate. -Butyl, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, toluene and the like. These can be used individually by 1 type or in mixture of 2 or more types.

  The undercoat layer 4 can be formed by applying a coating solution for forming the undercoat layer 4 on the conductive support 3 and drying it. As a coating method at this time, usual methods such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, a curtain coating method, and the like can be used.

FIG. 1C is a schematic cross-sectional view showing a third embodiment as a reference example of the electrophotographic photosensitive member of the present invention. The electrophotographic photosensitive member 120 shown in FIG. 1C has the same configuration as the electrophotographic photosensitive member 100 shown in FIG. 1A except that the protective layer 5 is provided on the photosensitive layer 6.

  The protective layer 5 is used to prevent chemical change of the charge transport layer 2 when the electrophotographic photosensitive member 120 is charged or to further improve the mechanical strength of the photosensitive layer 6.

  The protective layer 5 is formed, for example, by applying a coating solution containing a conductive material in an appropriate binder resin on the photosensitive layer 6. The conductive material is not particularly limited, and examples thereof include metallocene compounds such as N, N′-dimethylferrocene, N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1, Aromatic amine compounds such as 1′-biphenyl] -4,4′-diamine, molybdenum oxide, tungsten oxide, antimony oxide, tin oxide, titanium oxide, indium oxide, tin oxide and antimony, solid solution of barium sulfate and antimony oxide Carrier, mixture of the above metal oxide, titanium oxide, tin oxide, zinc oxide or barium sulfate mixed with the above metal oxide, or titanium oxide, tin oxide, zinc oxide or sulfuric acid For example, a single particle of barium coated with the above metal oxide.

  As the binder resin used for the protective layer 5, polyamide resin, polyvinyl acetal resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polyvinyl ketone resin, polystyrene resin, polyacrylamide resin, polyimide resin, polyamideimide Known resins such as resins are used. These can also be used by cross-linking each other as necessary.

  In addition, a fluorine-containing compound can be added to the protective layer 5 for the purpose of imparting surface lubricity. By improving the surface lubricity, the coefficient of friction with the cleaning member decreases, and the wear resistance can be improved. It also has the effect of preventing the adhesion of discharge products, developer, paper dust, etc. to the surface of the photoreceptor, which helps to improve the life of the photoreceptor.

  As the fluorine-containing compound, a fluorine atom-containing polymer such as polytetrafluoroethylene can be added as it is, or fine particles of these polymers can be added.

  The content of the fluorine-containing compound is preferably 20% by mass or less based on the total amount of the protective layer 5. When the content of the fluorine-containing compound exceeds 20% by mass, a problem may occur in the film formability of the crosslinked cured film.

  The protective layer 5 containing the above compound has sufficient oxidation resistance, but an antioxidant may be added for the purpose of imparting stronger oxidation resistance. Antioxidants are preferably hindered phenols or hindered amines, organic sulfur antioxidants, phosphite antioxidants, dithiocarbamate antioxidants, thiourea antioxidants, benzimidazole antioxidants. , Etc., may be used. As content of antioxidant, 15 mass% or less is preferable on the basis of the protective layer 5 whole quantity, and 10 mass% or less is still more preferable.

  Here, as the hindered phenol antioxidant, 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-hydroxybenzylphosphonate-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'-butylidene bis (3-methyl -6-t-butylphenol) and the like.

  Moreover, it is also possible to add the additive used for well-known coating-film formation to the protective layer 5, and add well-known additives, such as a leveling agent, a ultraviolet absorber, a light stabilizer, and surfactant. be able to.

  As a coating method of the coating liquid for forming the protective layer 5, 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 are used. Can be used.

  Moreover, as a solvent used for the coating liquid for forming the protective layer 5, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, toluene, water, methanol, ethanol, n-propanol, i-propanol, n-butanol, Usual organic solvents such as benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dimethyl ether and dibutyl ether can be used. These may be used alone or in combination of two or more, but it is preferable to use a solvent that hardly dissolves the photosensitive layer 6 to which the coating solution is applied.

  The thickness of the protective layer 5 having the above-described configuration is preferably 0.5 to 20 μm, more preferably 1 to 20 μm, and still more preferably 2 to 10 μm.

  In the electrophotographic photoreceptor of the present invention, from the viewpoint of obtaining higher resolution, the thickness of the functional layer above the charge generation layer is preferably 50 μm or less, and more preferably 40 μm or less. When the functional layer is a thin film, the combination of the undercoat layer 4 and the high-strength protective layer 5 described above is particularly effectively used.

  The preferred embodiment of the electrophotographic photoreceptor of the present invention has been described in detail above, but the electrophotographic photoreceptor of the present invention is not limited to the above embodiment. For example, as in the electrophotographic photoreceptor 130 shown in FIG. 2A, the undercoat layer 4 is provided between the conductive support 3 and the photosensitive layer 6, and the protective layer 5 is further provided on the photosensitive layer 6. It may be.

  In the electrophotographic photoreceptors 100, 110, and 120 of the above-described embodiment, the case where the photosensitive layer 6 has a laminated structure has been described. For example, the electrophotographic photoreceptor shown in FIG. As in 140, the photosensitive layer 6 may have a single layer structure. In this case, the undercoat layer 4 may be provided between the conductive support 3 and the photosensitive layer 6, and the protective layer 5 may be provided on the photosensitive layer 6. And the protective layer 5 may be provided.

  Further, an intermediate layer 30 may be provided between the photosensitive layer 6 and the undercoat layer 4 as in the electrophotographic photoreceptor 150 shown in FIG. The material used for the intermediate layer 30 is the same as the material used for the undercoat layer 4, such as a zirconium chelate compound, a zirconium alkoxide compound, and a zirconium coupling agent; a titanium chelate compound, a titanium alkoxide compound, and a titanate. Organic titanium compounds such as coupling agents; organoaluminum compounds such as aluminum chelate compounds and aluminum coupling agents; antimony alkoxide compounds; germanium alkoxide compounds; organic indium compounds such as indium alkoxide compounds and indium chelate compounds; manganese alkoxide compounds and manganese chelates Organic manganese compounds such as compounds; Organotin compounds such as tin alkoxide compounds and tin chelate compounds; Aluminum silicon Al Kishido compounds; aluminum titanium alkoxide compound; aluminum zirconium alkoxide compounds include organometallic compounds such as. Among these, organic zirconium compounds, organic titanyl compounds, and organoaluminum compounds are preferably used because of their low residual potential and good electrophotographic characteristics.

  Further, as in the case of the undercoat layer 4, the intermediate layer 30 includes vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris-2-methoxyethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltri Methoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-2-aminoethylaminopropyltrimethoxysilane, γ-mercapropropyltrimethoxysilane, γ -A silane coupling agent such as ureidopropyltriethoxysilane or β-3,4-epoxycyclohexyltrimethoxysilane can be contained and used.

  Furthermore, polyvinyl alcohol, polyvinyl methyl ether, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, polyamide, polyimide, casein, gelatin, polyethylene, polyester, phenol resin, vinyl chloride- Known binder resins such as a vinyl acetate copolymer, an epoxy resin, polyvinyl pyrrolidone, polyvinyl pyridine, polyurethane, polyglutamic acid, and polyacrylic acid can also be used. These mixing ratios can be appropriately set as necessary.

  Further, in the intermediate layer 30, similarly to the undercoat layer 4, an electron transport pigment can be mixed / dispersed and used. Examples of electron transport pigments include organic pigments such as perylene pigments, bisbenzimidazole perylene pigments, polycyclic quinone pigments, indigo pigments, and quinacridone pigments, and electron-withdrawing pigments such as cyano groups, nitro groups, nitroso groups, and halogen atoms. Examples thereof include organic pigments such as bisazo pigments and phthalocyanine pigments having a substituent, and inorganic pigments such as zinc oxide and titanium oxide. Among these pigments, perylene pigments, bisbenzimidazole perylene pigments and polycyclic quinone pigments are preferably used because of their high electron mobility. If the amount of the electron transporting pigment is too large, the strength of the undercoat layer is lowered and a coating film defect is generated, so that it is used at 95% by mass or less, preferably 90% by mass or less.

  Similar to the undercoat layer 4, the intermediate layer 30 is formed by applying a coating solution obtained by mixing / dispersing the above materials in a predetermined organic solvent on the undercoat layer 4 and removing the solvent by drying. Examples of the mixing / dispersing method in preparing the coating liquid for forming the intermediate layer 30 include a ball mill, a roll mill, a sand mill, an attritor, and an ultrasonic wave. Any organic solvent may be used as long as it does not cause gelation or aggregation when an organic metal compound or resin is dissolved and an electron transporting pigment is mixed / dispersed. Specifically, methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform , Chlorobenzene, toluene and the like, and these can be used alone or in admixture of two or more. The coating solution is dried at a temperature at which the solvent can be evaporated and a film can be formed.

  Thus, the thickness of the intermediate | middle layer 30 obtained is preferably 0.1-10 micrometers, and it is more preferable that it is 0.5-5 micrometers. When the film thickness of the intermediate layer 30 satisfies the above conditions, stable characteristics can be obtained even when the electrophotographic photoreceptor is continuously used for a long period of time.

  The electrophotographic photoreceptor of the present invention described above is provided in an image forming apparatus such as a laser beam printer, a digital copying machine, an LED printer, or a laser facsimile that emits near-infrared light or visible light, or such an image forming apparatus. Can be mounted on a process cartridge. The electrophotographic photoreceptor of the present invention can be used in combination with a one-component or two-component regular developer or reversal developer. The electrophotographic photosensitive member of the present invention is mounted on a contact charging type image forming apparatus using a charging roller or a charging brush, and good characteristics with little occurrence of current leakage can be obtained.

(Image forming apparatus and process cartridge)
4 and 5 are cross-sectional views schematically showing the basic configuration of a preferred embodiment of the image forming apparatus of the present invention.

  An image forming apparatus 200 shown in FIG. 4 includes an electrophotographic photoreceptor 7 of the present invention, a charging unit 8 for charging the electrophotographic photoreceptor 7 by a corona discharge method, a power source 9 connected to the charging unit 8, and a charging unit. Exposure means 10 that exposes the electrophotographic photosensitive member 7 charged by 8 to form an electrostatic latent image, and developing means that develops the electrostatic latent image formed by the exposure means 10 with toner to form a toner image. 11, a transfer unit 12 that transfers the toner image formed by the developing unit 11 to the transfer target 20, a cleaning unit 13, a static eliminator 14, and a fixing device 15.

  The image forming apparatus 210 shown in FIG. 5 has the same configuration as that of the image forming apparatus 200 shown in FIG. 4 except that the image forming apparatus 210 includes a charging unit 8 that charges the electrophotographic photoreceptor 7 of the present invention by a contact method. Have In particular, an image forming apparatus that employs a contact-type charging unit in which an AC voltage is superimposed on a DC voltage can be preferably used because it has excellent wear resistance. In this case, the static eliminator 14 may not be provided.

  Here, as the charging means 8, for example, a contact-type charger using a roller-like, brush-like, blade-like, film-like or pin-electrode-like conductive or semiconductive charging member, or scorotron charging using corona discharge. Non-contact chargers such as chargers and corotron chargers are used.

  Here, as the charging member in the contact-type charger, a member provided with an elastic layer, a resistance layer, a protective layer and the like on the outer peripheral surface of the core material is preferably used.

  Examples of the material for the core material include conductive materials such as iron, copper, brass, stainless steel, aluminum, and nickel. Also, a resin molded product in which conductive particles or the like are dispersed can be used.

As the material of the elastic layer, a material having conductivity or semiconductivity, for example, a material in which conductive particles or semiconducting particles are dispersed in a rubber material can be used. EPDM, polybutadiene, natural rubber, polyisobutylene, SBR, CR, NBR, silicone rubber, urethane rubber, epichlorohydrin rubber, SBS, thermoplastic elastomer, norbornene rubber, fluorosilicone rubber, ethylene oxide rubber, chloroprene rubber, isoprene Rubber, epoxy rubber or the like is used. Examples of the conductive particles or semiconductive particles include carbon black, zinc, aluminum, copper, iron, nickel, chromium, titanium and other metals, ZnO—Al ₂ O ₃ , SnO ₂ —Sb ₂ O ₃ , In ₂ O ₃ — Metal oxides such as SnO ₂ , ZnO—TiO ₂ , MgO—Al ₂ O ₃ , FeO—TiO ₂ , TiO ₂ , SnO ₂ , Sb ₂ O ₃ , In ₂ O ₃ , ZnO, and MgO can be used. These materials can be used individually by 1 type or in mixture of 2 or more types.

  Examples of the material of the resistance layer and the protective layer include those in which conductive particles or semiconductive particles are dispersed in a binder resin and the resistance is controlled. Binder resins include acrylic resin, cellulose resin, polyamide resin, methoxymethylated nylon, ethoxymethylated nylon, polyurethane resin, polycarbonate resin, polyester resin, polyethylene resin, polyvinyl resin, polyarylate resin, polythiophene resin, PFA, FEP Polyolefin resin such as PET, styrene butadiene resin or the like is used. As the conductive particles or semiconductive particles, the same carbon black, metal, and metal oxide as the elastic layer are used. If necessary, an antioxidant such as hindered phenol and hindered amine, a filler such as clay and kaolin, and a lubricant such as silicone oil can be added.

  As a means for forming these layers, blade coating method, Meyer bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating method, melt molding method, injection molding method, etc. should be used. Can do.

  When the photosensitive member is charged using these conductive members, a voltage is applied to the conductive member. The applied voltage may be a DC voltage or a DC voltage superimposed with an AC voltage.

  There is no particular limitation on the charging method used in the electrophotographic photosensitive member of the present invention. However, in recent years, a contact charging method that generates less ozone and has a low environmental load tends to be used preferably. In general, the contact charging method has a weak charging ability as compared with non-contact charging methods such as scorotron and corotron, and is likely to be a problem particularly in an image forming apparatus that requires a high-speed response. When the charging capability is weak, the charge remaining in the photosensitive layer of the electrophotographic photosensitive member causes image quality defects such as fogging. However, according to the electrophotographic photosensitive member of the present invention, the charge transport material of the present invention present in the charge transport layer has a high charge transport ability and can sufficiently reduce the formation of charge traps. Image quality defects are less likely to occur and can be suitably used in combination with a contact charging system.

  The charging means 8 has a predetermined charging potential that is higher than the charging potential in the first electrophotographic process including charging by the charging means 8, exposure by the exposure means 10, development by the developing means 11, and transfer by the transfer means 12. It is preferable that the unit has a function of adjusting and controlling the charging potential so that the charging potential is reduced when it is repeated a number of times. Hereinafter, a specific method for adjusting and controlling the charging potential on the surface of the electrophotographic photosensitive member as described above will be described with reference to the drawings.

  In the image forming apparatus 200 shown in FIG. 4, a power source 9 is connected to the charging unit 8, and a charging potential control device (not shown) is electrically connected to the power source 9. A measuring device (not shown) for measuring the number of rotations of the electrophotographic photosensitive member is electrically connected. The charging potential control device controls the electric field applied to the photosensitive layer from the power source 9 via the charging means 8, and thereby reduces the charging potential on the surface of the photosensitive layer when the electrophotographic process is repeated a predetermined number of times. be able to.

  FIG. 6 is a process diagram showing an example of a method for adjusting and controlling the charging potential to be smaller when the electrophotographic process is repeated a predetermined number of times than the charging potential in the first electrophotographic process. First, in step S1, the number of rotations of the electrophotographic photosensitive member 7 serving as an index of the number of repetitions of the electrophotographic process is measured by the measuring device. Next, in step S2, a data signal relating to the measured number of rotations is sent from the measuring device to the charging potential control device and converted into the number of repetitions of the electrophotographic process. The charging potential control device includes data relating to the correlation between the thickness of the photosensitive layer when the electrophotographic process is repeated a predetermined number of times and the charging potential when a predetermined electric field is applied to the photosensitive layer having the thickness. Is input in advance, and based on the converted number of electrophotographic processes, the film thickness of the photosensitive layer at the number of repetitions is estimated. Then, the electric field to be applied to the photosensitive layer is determined so that the charging potential is lowered when an electric field is applied to the photosensitive layer having the estimated film thickness. Further, in step S3, a control signal relating to the determined electric field is sent to the power source 9, and an electric field based on the control signal is applied to the photosensitive layer via the charging roll. In this manner, the charged potential of the photosensitive layer can be lowered with an increase in the number of repetitions of the electrophotographic process.

  In addition, although the said method includes the process of converting the rotation frequency of the electrophotographic photoreceptor 7 into the repetition number of an electrophotographic process, this conversion process is not necessarily required. That is, the data on the correlation between the thickness of the photosensitive layer when the electrophotographic photoreceptor 7 rotates a predetermined number of times and the charging potential when a predetermined electric field is applied to the photosensitive layer having the thickness is charged potential control. The film thickness of the photosensitive layer at the number of rotations may be estimated directly from the number of rotations of the electrophotographic photosensitive member 7 measured in advance by inputting into the apparatus.

  Further, the electric field applied to the photosensitive layer may be determined directly from the diameter and the number of rotations of the electrophotographic photosensitive member without providing a step of estimating the film thickness (or wear amount) of the photosensitive layer. That is, a theoretical curve for the electric field to be applied to the electrophotographic photosensitive member in order to lower the charging potential when the electrophotographic process is repeated a predetermined number of times is previously obtained as a function of the diameter and the number of rotations of the electrophotographic photosensitive member 7. By obtaining and reducing the electric field according to the theoretical curve, the charged potential of the photosensitive layer can be lowered when the electrophotographic process is repeated a predetermined number of times.

  The electric field reduction schedule in the present invention is not particularly limited as long as it is possible to make the charging potential smaller when the electrophotographic process is repeated a predetermined number of times than the charging potential in the first electrophotographic process. For example, the electric field may be continuously reduced as the electrophotographic process increases as shown in FIG. 7A, or the electric field is reduced stepwise as shown in FIG. 7B. Also good.

  Based on the correlation between the thickness of the photosensitive layer when the electrophotographic process is repeated a predetermined number of times and the charging potential when a predetermined electric field is applied to the photosensitive layer having the thickness, the charging is performed. By controlling the electric field applied to the photosensitive layer, the operation of reducing the charged potential on the surface of the photosensitive layer with the increase in the number of repetitions of the electrophotographic process is effectively performed, so image quality defects such as fog are reliably generated. And good image quality can be obtained over a long period of time.

  As the exposure means 10, an optical system device that can expose a light source such as a semiconductor laser, an LED (light emitting diode), and a liquid crystal shutter in a desired image-like manner on the surface of the electrophotographic photosensitive member is used.

  As the developing means 11, a conventionally known developing means using a regular or reversal developer such as a one-component system or a two-component system is used.

The shape of the toner used for the developing means 11 is not particularly limited, and it can be used even if it is indefinite, spherical, or any other specific shape. Among these, spherical toners are preferably used from the viewpoint of high image quality and ecology. The spherical toner is a toner having a spherical shape represented by an average shape factor (ML ² / A) of 100 to 145, preferably 100 to 140, in order to achieve high transfer efficiency. When this average shape factor (ML ² / A) is larger than 145, the transfer efficiency is lowered, and the deterioration of the image quality of the print sample tends to be visually confirmed.

  The spherical toner contains at least a binder resin and a colorant. The spherical toner may preferably use 2 to 12 μm particles, more preferably 3 to 9 μm particles.

  Examples of the binder resin include homopolymers and copolymers such as styrenes, monoolefins, vinyl esters, α-methylene aliphatic monocarboxylic acid esters, vinyl ethers, and vinyl ketones. Typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. Examples thereof include coalescence, polyethylene, and polypropylene. Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like.

  Coloring agents include magnetic powders such as magnetite and ferrite, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, and lamp black. Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 is a typical example.

  The spherical toner may be subjected to internal addition treatment or external addition treatment with a known additive such as a charge control agent, a release agent, and other inorganic fine particles.

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

  Known charge control agents can be used, but charge control agents such as azo-based metal complex compounds, metal complex compounds of salicylic acid, and resin types containing polar groups can be used.

  As other inorganic fine particles, small-diameter inorganic fine particles having an average primary particle size of 40 nm or less can be used for the purpose of powder flowability, charge control, etc. Larger inorganic or organic fine particles may be used in combination. As these other inorganic fine particles, known ones can be used.

  In addition, small-diameter inorganic fine particles are effective because surface treatment increases dispersibility and increases the powder flowability.

  The spherical toner is not particularly limited by the production method, and can be obtained by a known method. Specific examples include a kneading and pulverizing method, a method of changing the shape of particles obtained by a kneading and pulverizing method with a mechanical impact force or thermal energy, an emulsion polymerization aggregation method, a dissolution suspension method, and the like. In addition, a manufacturing method may be performed in which the spherical toner obtained by the above method is used as a core, and agglomerated particles are further adhered and heat-fused to have a core-shell structure. When the external additive is added, it can be produced by mixing the spherical toner and the external additive with a Henschel mixer or a V blender. In addition, when the spherical toner is manufactured by a wet method, it can be externally added by a wet method.

  The exposure means 10 is a means for forming an electrostatic latent image on the electrophotographic photosensitive member 7 during one rotation of the electrophotographic photosensitive member after starting the stationary electrophotographic photosensitive member 7. Is preferred. This eliminates the idling time and sufficiently shortens the time (First Copy Output Time (FCOT)) from when the copy start button is pressed until the trailing edge of the first sheet is ejected to the tray. In addition, by using the charge transport material of the present invention, it is possible to obtain good image quality in which generation of ghosts is sufficiently suppressed.

  As the transfer means 12, a contact transfer charger using a belt, a roller, a film, a rubber blade or the like, a scorotron transfer charger using a corona discharge, a corotron transfer charger, or the like is used.

  The cleaning means 13 is for removing residual toner adhering to the surface of the electrophotographic photosensitive member after the transfer process, and the electrophotographic photosensitive member cleaned by this is used in the next image forming process (electrophotographic process). ) Repeatedly.

  The static eliminator 14 is for preventing a phenomenon in which the residual potential of the electrophotographic photosensitive member is brought into the next cycle, and thereby improves the image quality when the electrophotographic photosensitive member is repeatedly used. Can do.

  Although not shown in FIGS. 4 and 5, the image forming apparatus of the present invention may include an intermediate transfer unit. As the intermediate transfer means, one having a structure in which an elastic layer containing rubber, elastomer, resin, etc. and at least one coat layer is laminated on a conductive support can be used as the material. The materials used are conductive to polyurethane resins, polyester resins, polystyrene resins, polyolefin resins, polybutadiene resins, polyamide resins, polyvinyl chloride resins, polyethylene resins, fluororesins, etc. And those obtained by dispersing and mixing carbon particles, metal powder, and the like. Examples of the shape of the intermediate transfer unit include a roller shape and a belt shape.

  FIG. 8 is a cross-sectional view schematically showing a basic configuration of another embodiment of the image forming apparatus of the present invention. An image forming apparatus 220 shown in FIG. 8 is an intermediate transfer type image forming apparatus. In the housing 400, four electrophotographic photosensitive members 401a to 401d (for example, the electrophotographic photosensitive member 401a is yellow and the electrophotographic photosensitive member 401b is provided. Magenta, electrophotographic photosensitive member 401c can be formed with cyan, and electrophotographic photosensitive member 401d can be formed with black.) Are arranged in parallel with each other along intermediate transfer belt 409.

  Here, the electrophotographic photoreceptors 401a to 401d mounted on the image forming apparatus 220 are the electrophotographic photoreceptors of the present invention.

  Each of the electrophotographic photoreceptors 401a to 401d can be rotated in a predetermined direction (counterclockwise on the paper surface), and the charging rolls 402a to 402d, the developing devices 404a to 404d, and the primary transfer roll along the rotation direction. 410a to 410d and cleaning blades 415a to 415d are arranged. Each of the developing devices 404a to 404d can be supplied with toner of four colors of black, yellow, magenta and cyan accommodated in the toner cartridges 405a to 405d, and the primary transfer rolls 410a to 410d are respectively intermediate transfer belts. 409 is in contact with the electrophotographic photoreceptors 401a to 401d.

  Further, a laser light source (exposure device) 403 is disposed at a predetermined position in the housing 400, and the surface of the charged electrophotographic photoreceptors 401a to 401d is irradiated with laser light emitted from the laser light source 403. Is possible. Accordingly, charging, exposure, development, primary transfer, and cleaning are sequentially performed in the rotation process of the electrophotographic photosensitive members 401a to 401d, and the toner images of the respective colors are transferred onto the intermediate transfer belt 409 in an overlapping manner.

  The intermediate transfer belt 409 is supported with a predetermined tension by a drive roll 406, a backup roll 408, and a tension roll 407, and can rotate without causing deflection due to the rotation of these rolls. Further, the secondary transfer roll 413 is disposed so as to contact the backup roll 408 via the intermediate transfer belt 409. The intermediate transfer belt 409 passing between the backup roll 408 and the secondary transfer roll 413 is cleaned by, for example, a cleaning blade 416 disposed in the vicinity of the drive roll 406 and then repeatedly used for the next image forming process. Is done.

  A tray (transfer medium tray) 411 is provided at a predetermined position in the housing 400, and the transfer medium 500 such as paper in the tray 411 is transferred to the intermediate transfer belt 409 and the secondary transfer roll by the transfer roll 412. Then, the paper is sequentially transferred between the two fixing rolls 414 that are in contact with each other and the two fixing rolls 414, and then discharged to the outside of the housing 400.

  In the above description, the case where the intermediate transfer belt 409 is used as the intermediate transfer member has been described. However, the intermediate transfer member may have a belt shape like the intermediate transfer belt 409 or a drum shape. Also good.

  When the intermediate transfer member is belt-shaped, a conventionally known resin can be used as the resin material used as the base material. For example, polyimide resin, polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene terephthalate (PAT), ethylenetetrafluoroethylene copolymer (ETFE) / PC, ETFE / PAT, PC / PAT blend material, polyester Resin materials such as polyether ether ketone and polyamide, and resin materials using these as main raw materials. Furthermore, a resin material and an elastic material can be blended and used.

  As an elastic material, polyurethane, chlorinated polyisoprene, NBR, chloropyrene rubber, EPDM, hydrogenated polybutadiene, butyl rubber, silicone rubber, or the like can be used, or a material obtained by blending two or more kinds can be used. If necessary, a conductive agent imparting electronic conductivity or a conductive agent having ionic conductivity is added to the resin material and elastic material used for these base materials in combination of one kind or two or more kinds. Among these, it is preferable to use a polyimide resin in which a conductive agent is dispersed from the viewpoint of excellent mechanical strength. As the conductive agent, a conductive polymer such as carbon black, metal oxide, or polyaniline can be used. When a belt-shaped configuration such as the intermediate transfer belt 409 is employed as the intermediate transfer member, the thickness of the belt is generally preferably 50 to 500 μm and more preferably 60 to 150 μm, but is appropriately selected according to the hardness of the material. be able to.

  As a manufacturing method of the intermediate transfer belt 409, for example, when manufacturing a belt made of a polyimide resin in which a conductive agent is dispersed, a polyimide precursor is used as described in JP-A-63-311263. 5 to 20% by weight of carbon black as a conductive agent is dispersed in a polyamic acid solution, the dispersion is cast on a metal drum and dried, and then the film peeled from the drum is stretched at a high temperature to obtain a polyimide film. And can be manufactured by cutting it into an appropriate size to obtain an endless belt.

  The film molding is generally performed by injecting a polyamic acid solution film-forming stock solution in which a conductive agent is dispersed into a cylindrical mold and, for example, heating at 100 to 200 ° C. at a rotational speed of 500 to 2000 rpm. The film was formed into a film by a centrifugal molding method while rotating, and then the obtained film was demolded in a semi-cured state and covered with an iron core. It can be carried out by proceeding a ring-closing reaction) and carrying out main curing. In addition, the stock solution is cast on a metal sheet to a uniform thickness and heated to 100 to 200 ° C. to remove most of the solvent in the same manner as described above, and then gradually raised to a high temperature of 300 ° C. or higher. There is also a method of forming a polyimide film. The intermediate transfer member may have a surface layer.

  When a drum-shaped configuration is adopted as the intermediate transfer member, it is preferable to use a cylindrical substrate formed of aluminum, stainless steel (SUS), copper, or the like as the substrate. If necessary, an elastic layer can be coated on the cylindrical substrate, and a surface layer can be formed on the elastic layer.

  In general, when an intermediate transfer member is used, a potential is applied to the surface of the electrophotographic photosensitive member through the intermediate transfer member, so that the residual charge existing in the photosensitive layer is affected. The image in the cycle is likely to cause an image quality defect such as a decrease that appears as an afterimage in the next cycle. However, according to the electrophotographic photosensitive member of the present invention, the charge transport material of the present invention present in the charge transport layer has a high charge transport ability and can sufficiently reduce the formation of charge traps. Image quality defects are less likely to occur and can be suitably used in combination with an intermediate transfer member.

  The transfer target in the present invention is not particularly limited as long as it is a medium for transferring a toner image formed on the electrophotographic photosensitive member. For example, the transfer medium refers to the transfer medium when transferring directly from the electrophotographic photosensitive member to a transfer medium such as paper, and when the intermediate transfer body is used, the intermediate transfer body is referred to as the transfer medium. Point to.

  FIG. 9 is a sectional view schematically showing a basic configuration of a preferred embodiment of the process cartridge of the present invention. In the process cartridge 300, together with the electrophotographic photosensitive member 7 of the present invention, a charging unit 8, a developing unit 11, a cleaning unit 13, an opening 18 for exposure, and a static eliminator 14 are combined using a mounting rail 16 and integrated. It has become. The process cartridge 300 is detachable from an image forming apparatus main body including the transfer unit 12, the fixing device 15, and other components (not shown). It constitutes.

  FIG. 10 is a cross-sectional view schematically showing a basic configuration of another preferred embodiment of the process cartridge of the present invention. In FIG. 10, a process cartridge 310, together with the electrophotographic photosensitive member 7 of the present invention, includes a charging device 208, a developing device 211, a cleaning device (cleaning means) 213, an opening 218 for exposure, and a discharge exposure. The opening 217 is combined and integrated using the mounting rail 216. The process cartridge 310 is detachably attached to an image forming apparatus main body including a transfer unit 212, a fixing device 215, and other components not shown. The image forming apparatus and the image forming apparatus main body are detachable. It constitutes.

  Since the image forming apparatus and the process cartridge of the present invention described above include the electrophotographic photosensitive member using the charge transport material of the present invention, stable image quality can be obtained over a long period without causing image quality defects. it can.

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

<Synthesis of charge transport materials>
( Production Example 1: Synthesis of Compound (I))
10 parts by weight of 4- [bis- (3,4-dimethyl-phenyl) -amino] -benzaldehyde, 15.7 parts by weight of cinnamyltriphenylphosphonium bromide and 1.3 parts by weight of sodium methylate in tetrahydrofuran The reaction was stirred at room temperature for 5 hours. After completion of the reaction, extraction was performed by adding water and further adding toluene. After concentrating the toluene layer, it was purified by column chromatography using a mixed solvent having a volume ratio of toluene / hexane of 2/1 to obtain the target compound (I) represented by the following general formula (I). The IR spectrum of the compound is shown in FIG. The IR spectrum was measured with an infrared spectrophotometer (HORIBA FT-IR, manufactured by Horiba, Ltd.) under the conditions of a resolution of 4 cm ⁻¹ , a scan count of 20 times, and a measurement gain of 2.

( Production Example 2: Synthesis of Compound (II))
10 parts by weight of 4- [bis- (3,4-dimethyl-phenyl) -amino] -benzaldehyde, 16 parts by weight of 4-methylcinnamyl triphenylphosphonium bromide and 1.3 parts by weight of sodium methylate in tetrahydrofuran The reaction was stirred at 25 ° C. for 6 hours. After completion of the reaction, extraction was performed by adding water and further adding toluene. After concentrating the toluene layer, it was purified by column chromatography using a mixed solvent having a volume ratio of toluene / hexane of 2/1 to obtain the target compound (II) represented by the following general formula (II).

( Production Example 3: Synthesis of Compound (III))
10 parts by mass of 4- [bis- (3,4-dimethyl-phenyl) -amino] -benzaldehyde, 17 parts by mass of α-phenylcinnamyl triphenylphosphonium bromide and 1.4 parts by mass of sodium methylate in tetrahydrofuran The reaction was stirred at 30 ° C. for 8 hours. After completion of the reaction, extraction was performed by adding water and further adding toluene. After concentrating the toluene layer, it was purified by column chromatography using a mixed solvent having a volume ratio of toluene / hexane of 2/1 to obtain the target compound (III) represented by the following general formula (III).

<Synthesis of 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.

Next, 6 parts by mass of the type I hydroxygallium phthalocyanine obtained above was used together with 90 parts by mass of N, N-dimethylformamide and 350 parts by mass of glass spherical media with an outer diameter of 0.9 mm using a glass ball mill. And then wet pulverized 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 λ _MAX in the range of 600 to 900 nm of the spectral absorption spectrum of hydroxygallium phthalocyanine was 827 nm. 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 X-ray diffraction spectrum of the obtained hydroxygallium phthalocyanine pigment is shown in FIG. 11, and the spectral absorption spectrum is shown in FIG.

<Production of electrophotographic photoreceptor>
(Example 1 )
First, 100 parts by mass of zinc oxide (manufactured by Teika, average particle size: 70 nm, specific surface area value: 15 m ² / g) is stirred and mixed with 500 parts by mass of toluene, and a silane coupling agent “KBM603” (manufactured by Shin-Etsu Chemical Co., Ltd., Product name) 1.25 parts by mass were added and stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure, and baking was performed at 150 ° C. for 2 hours to obtain a surface-treated zinc oxide pigment.

  Next, 60 parts by mass of the obtained surface-treated zinc oxide pigment, 13.5 parts by mass of a blocked isocyanate “Sumijoule 3175” (trade name, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent, and a butyral resin “BM-1” "38 parts by mass of a solution obtained by dissolving 15 parts by mass of Sekisui Chemical Co., Ltd. in 85 parts by mass of methyl ethyl ketone and 25 parts by mass of methyl ethyl ketone were mixed, and this was mixed in a sand mill for 2 hours using 1 mmφ glass beads. A dispersion was obtained by dispersing. As a catalyst, 0.005 part by mass of dioctyltin dilaurate and 3.4 parts by mass of silicone resin particles “Tospearl 130” (manufactured by GE Toshiba Silicone Co., Ltd., trade name) are added to the resulting dispersion as a coating for forming an undercoat layer. A liquid was obtained. This coating solution was applied onto an aluminum substrate having a thickness of 1 mm by a dip coating method, followed by drying and curing at 170 ° C. for 40 minutes to form an undercoat layer having a thickness of 25 μm.

  Next, a solution obtained by dissolving 1 part by mass of vinyl chloride / vinyl acetate copolymer resin “VMCH” (trade name, manufactured by Nippon Unicar Co., Ltd.) in 100 parts by mass of n-butyl acetate, and 1 mass of hydroxygallium phthalocyanine obtained above. Were mixed in a sand mill for 5 hours together with 150 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 the subbing layer formed above and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.20 μm.

Next, 4 parts by mass of the compound (I) synthesized above as a charge transport material, 6 parts by mass of a bisphenol Z-type polycarbonate resin having a viscosity average molecular weight of 30,000 as a binder resin, 80 parts by mass of tetrahydrofuran, and 2,6-di A coating solution for forming a charge transport layer was prepared by mixing 0.2 parts by mass of -t-butyl-4-methylphenol. The resulting dip coating a coating solution was coated on the charge generation layer formed above, and dried by heating for 40 minutes at 120 ° C., to form a charge transport layer having a thickness of 25 [mu] m, electrophotographic of Example 1 A photoconductor was prepared.

(Example 2 )
An electrophotographic photoreceptor of Example 2 was produced in the same manner as Example 1 except that Compound (II) synthesized above was used instead of Compound (I) as the charge transport material.

(Example 3 )
An electrophotographic photoreceptor of Example 3 was produced in the same manner as in Example 1 except that the compound (III) synthesized above was used instead of the compound (I) as the charge transport material.

( Reference Example 1 )
An electrophotographic photosensitive member of Reference Example 1 was produced in the same manner as in Example 1 except that an alumite substrate having an anodized surface was used instead of the aluminum substrate and no undercoat layer was formed.

(Comparative Example 1)
An electrophotographic photosensitive member of Comparative Example 1 was prepared in the same manner as in Example 1 except that the compound (IV) represented by the following general formula (IV) was used instead of the compound (I) as the charge transport material. did.

<Electrophotographic characteristic evaluation test of electrophotographic photosensitive member>
The electrophotographic characteristics of the electrophotographic photosensitive members of Examples 1 to 3, Reference Example 1 and Comparative Example 1 obtained above were evaluated by the following procedure.

(1) Characteristic evaluation at the initial stage of use Using a 20 mmφ small area mask on the photoconductor, and using an electrostatic copying paper test apparatus “EPA8200” (manufactured by Kawaguchi Electric Co., Ltd.) in an environment of 20 ° C. and 50% RH, The photoreceptor was negatively charged by -5.0 kV corona discharge (charging process). Then, the photosensitive member charged with halogen lamp light dispersed at 780 nm using an interference filter was adjusted and irradiated to 5.0 μW / cm ² on the surface of the photosensitive member (exposure process). After measuring the initial surface potential V ₀ (V), the half-exposure amount E _1/2 (μJ / cm ² ) until the surface potential becomes ½ of V ₀ , and the surface potential V ₀ at this time. The dark decay rate (DDR) (%) obtained by {(V ₀ −V ₁ ) / V ₀ } × 100 was measured with the surface potential after 1 second as V ₁ . These results are shown in Table 2.

(2) repeating the charging step and exposure step and characterized above in the use neutralization and repeated 10,000 times an operation that once the initial surface potential V ₀ at this time _(V), the surface potential of V ₀ 1 / The half-exposure amount E _1/2 (μJ / cm ² ) until ² and the dark decay rate (DDR) (%) were measured. These results are shown in Table 2.

<Abrasion test of charge transport layer>
For the charge transport materials of the compounds (I) to (IV) synthesized above, the wear resistance of the charge transport layer containing these charge transport materials was evaluated by the following method.

First, a charge transport material and a binder resin (bisphenol Z-type polycarbonate resin having a viscosity average molecular weight of 30,000) are dissolved in THF at a mass ratio of 2: 3, and this solution is 107 mm in diameter and 100 μm in thickness by a solvent cast method. A sample for evaluation was produced by forming a film on a flat petri dish. A rotary abrasion tester “5130ABRASER” (manufactured by Toyo Seiki Co., Ltd.) was applied to the sample for evaluation, and 500 g of excess weight was added and the amount of wear after 1000 rotations was measured. The obtained results are shown in Table 3. Reference Examples 2 to 4 correspond to compounds (I) to (III), respectively, and Reference Comparative Example 1 corresponds to compound (IV).

3 is a schematic cross-sectional view showing first to third embodiments of the electrophotographic photosensitive member of the present invention. FIG. It is a schematic cross section which shows other embodiment of the electrophotographic photoreceptor of this invention. It is. It is a schematic cross section which shows other embodiment of the electrophotographic photoreceptor of this invention. 1 is a cross-sectional view schematically showing a basic configuration of a preferred embodiment of an image forming apparatus of the present invention. It is sectional drawing which shows schematically the basic composition of other suitable one Embodiment of the image forming apparatus of this invention. FIG. 5 is a process diagram showing an example of a method for reducing the charged potential of a photosensitive layer when an electrophotographic process is repeated a predetermined number of times. It is a graph which shows an example of the correlation (electric field reduction schedule) with the repetition number of an electrophotographic process, and the electric field applied to a photosensitive layer. It is sectional drawing which shows schematically the basic composition of other suitable one Embodiment of the image forming apparatus of this invention. 1 is a cross-sectional view schematically showing a basic configuration of a preferred embodiment of a process cartridge of the present invention. It is sectional drawing which shows schematically the basic composition of other suitable one Embodiment of the process cartridge of this invention. It is a powder X-ray diffraction pattern of the hydroxygallium phthalocyanine pigment produced in the Example. It is a spectrum absorption spectrum of the hydroxygallium phthalocyanine pigment produced in the Example. 2 is a diagram showing an IR spectrum of the charge transport material obtained in Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Charge generating layer, 2 ... Charge transport layer, 3 ... Conductive support body, 4 ... Undercoat layer, 5 ... Protective layer, 6 ... Photosensitive layer, 7 ... Electrophotographic photoreceptor, 8 ... Charging means, 9 ... Power supply DESCRIPTION OF SYMBOLS 10 ... Exposure means, 11 ... Developing means, 12 ... Transfer means, 13 ... Cleaning means, 14 ... Static eliminator, 15 ... Fixing device, 16 ... Mounting rail, 18 ... Opening for exposure, 20 ... Transfer object 30 ... intermediate layer, 100,110,120,130,140,150 ... electrophotographic photosensitive member, 200,210,220 ... image forming apparatus, 208 ... charging device, 209 ... power supply, 210 ... exposure device, 211 ... development 212, transfer device, 213, cleaning device, 214 ... discharger, 215 ... fixing device, 216 ... mounting rail, 217 ... opening for discharge exposure, 218 ... opening for exposure, 300, 310 ... process Cartridges, 500 ... the transfer medium.

Claims (3)

A conductive support, an undercoat layer, a charge generation layer containing 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, and the following general formula: An electrophotographic photoreceptor comprising a charge transport layer containing a charge transport material having a structure represented by (1) in this order .


[In the formula (1), Ar ¹ represents a substituted or unsubstituted aromatic group, X ¹ represents a hydrogen atom, a substituted or unsubstituted aromatic group, and R ¹ , R ² , R ³ and R ⁴ represent Each independently represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 4 carbon atoms. ] An electrophotographic photoreceptor according to claim 1 ;
Charging means for charging the electrophotographic photosensitive member; developing means for developing a latent electrostatic image formed on the electrophotographic photosensitive member with toner to form a toner image; and the transferred electron At least one selected from the group consisting of cleaning means for removing toner remaining on the surface of the photoconductor;
A process cartridge comprising: An electrophotographic photoreceptor according to claim 1 ;
Charging means for charging the electrophotographic photosensitive member;
Exposure means for forming an electrostatic latent image on the electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image formed on the electrophotographic photosensitive member with toner to form a toner image;
Transfer means for transferring the toner image to a transfer object;
An image forming apparatus comprising: