JP2005189721A - Electrophotographic photoreceptor, process cartridge and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor capable of achieving a ghost image of a new severe level while maintaining high sensitivity, a process cartridge with the electrophotographic photoreceptor, and an electrophotographic apparatus. <P>SOLUTION: In the electrophotographic photoreceptor having at least a charge generating layer and a charge transport layer in this order on a conductive substrate, wherein the charge transport layer contains a hole transport material, a universal hardness of a surface layer of the electrophotographic photoreceptor is ≥230 N/mm<SP>2</SP>and a charge generating material and an electron transport material are contained in the charge generating layer. The process cartridge with the electrophotographic photoreceptor and the electrophotographic apparatus are also provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member, a process cartridge, and an electrophotographic apparatus, and more specifically, an electrophotographic material containing a charge generating material and at least an electron transporting material in a charge generating layer in a laminated electrophotographic photosensitive member. The present invention relates to a photoconductor, a process cartridge having the electrophotographic photoconductor, and an electrophotographic apparatus.

  Conventionally, as electrophotographic photoreceptors, inorganic electrophotographic photoreceptors mainly composed of inorganic photoconductive compounds such as selenium, zinc oxide and cadmium sulfide have been widely used. In recent years, as seen in Patent Document 1 to Patent Document 5, etc., a stacked organic material having two functionally separated layers, a charge transport layer in which an organic photoconductive substance is bound with a resin or the like, and a charge generation layer. Various proposals have been made regarding electrophotographic photosensitive members. In particular, an electrophotographic photosensitive member having a layer structure in which a charge transport layer is provided on a charge generation layer is excellent in durability and is currently mainstream. For example, Patent Document 6 discloses an electrophotographic photosensitive member having a charge transfer layer containing triallyl pyrazoline, and Patent Document 7 discloses a charge generation layer composed of a derivative of perylene pigment and a charge composed of a condensate of 3-propylene and formaldehyde. An electrophotographic photoreceptor comprising a moving layer is disclosed. Further, as an electrophotographic photoreceptor using a disazo pigment or a trisazo pigment as a charge generation material, there are Patent Document 8 and Patent Document 9. Further, the organic photoconductive compound can freely select the photosensitive wavelength region of the electrophotographic photosensitive member depending on the compound. For example, with regard to azo-based organic pigments, the substances disclosed in Patent Document 10 and Patent Document 11 are those that exhibit high sensitivity in the visible region, and the substances disclosed in Patent Document 12 and Patent Document 13 Some have sensitivity even in the infrared region.

  Of these materials, materials having sensitivity in the red or infrared region are used in laser beam printers, LED printers, and the like that have made remarkable progress in recent years, and the frequency of demand thereof is increasing. Conventionally, copper phthalocyanine (Patent Document 14), metal-free phthalocyanine, and the like are listed as materials having sensitivity in the infrared region, but they are insufficient for increasing the sensitivity today. Further, in Patent Document 15 and the like, it has been proposed to increase sensitivity by adding an organic acceptor to the charge generation layer in the laminated organic electrophotographic photosensitive member, but this is not sufficient. Oxytitanium phthalocyanine pigments (Patent Literature 16 and Patent Literature 17), gallium phthalocyanine pigments (Patent Literature 18 and Patent Literature 19), chlorogallium phthalocyanine pigments (Patent Literature 20 and Patent Literature 21), etc. Is attracting attention.

  However, the development of today's electrophotographic technology is remarkable, and very advanced technology is required for the characteristics required for electrophotographic photoreceptors. For example, the process speed is increasing year by year, and charging characteristics, sensitivity, durability stability, and the like have been demanded. In particular, in recent years, high-quality images have been avoided as represented by colorization, and black-and-white images that have been character-centered have become more and more halftone images and solid images represented by photographs. Their image quality is increasing year by year. In particular, a phenomenon in which the light-irradiated portion of one image is darkened only in the light-irradiated portion in the halftone image at the next rotation, a so-called positive ghost image, on the contrary, the density of the portion is lightened. The permissible range for so-called negative ghosts and the like has become much stricter than the permissible range for black and white printers and black and white copiers. These ghost images use a highly sensitive charge generation material, because the number of carriers is large, and electrons after holes are injected into the charge transport layer are likely to remain in the charge generation layer, resulting in a memory. It is considered that this phenomenon is particularly remarkable in recent high-sensitivity charge generation materials. On the other hand, cost reduction and miniaturization are evolving year by year, and there is an increasing demand for less technology such as cleaner-less and pre-exposure-less. In particular, black-and-white laser printers and black-and-white copiers are often not equipped with pre-exposure with ghost image curing, and color printers and color copiers do not have pre-exposure. It's easy to imagine. Therefore, achieving a ghost image level in a color machine without pre-exposure requires a technique that is much more difficult than achieving a ghost level allowed in a black and white printer or black and white copier.

Patent Document 22 and Patent Document 23 disclose measures against ghosts by using type II chlorogallium phthalocyanine, but ghosts are evaluated under conditions in which the main body has pre-exposure. Are very different. Patent Document 24 discloses that a residual potential is reduced and a ghost is reduced by including an acceptor compound in a charge generation layer using oxytitanium phthalocyanine. However, after leaving the electrophotographic photoreceptor charged at +500 V for 5 hours to make the phenomenon noticeable, ghost evaluation is performed under certain conditions of pre-exposure. This is different from a normal ghost. In addition, the addition of an electron transport material, an electron acceptor or an electron withdrawing substance to the charge generation layer is disclosed in Patent Documents 25 to 32, etc., but is effective for the severe ghost level as described above. It wasn't. Further, Patent Document 33 discloses a method for producing a phthalocyanine pigment which is produced by adding an electron carrier material during the phthalocyanine pigmentation step, but in this publication, the electron carrier material is close to the charge generation material. Although it is disclosed that high sensitivity is achieved thereby, this is also not effective for the severe ghost level as described above. As described above, there has been a demand for an electrophotographic photosensitive member that satisfies severe ghost levels in printers and copying machines without pre-exposure, particularly color machines.
JP-A-57-54942 JP 60-59355 A JP-A-61-203461 JP-A 62-47054 JP-A 62-67094 U.S. Pat. No. 3,378,851 U.S. Pat. No. 3,871,882 JP 56-46237 A JP-A-60-111249 JP 60-272754 A JP 56-167759 A JP-A-57-195767 Japanese Patent Laid-Open No. 61-228453 Japanese Patent Laid-Open No. 50-38543 JP-A-61-2157 JP-A-63-366 JP-A-1-319934 JP-A-5-249716 Japanese Patent Laid-Open No. 5-263007 JP-A-5-188615 JP-A-5-194523 Japanese Patent Laid-Open No. 11-172142 JP 2002-91039 A JP 7-104495 A Japanese Patent Laid-Open No. 2-136860 JP-A-2-136661 Japanese Patent Laid-Open No. 2-146048 Japanese Patent Laid-Open No. 2-146049 JP-A-2-146050 JP-A-5-150498 JP-A-6-313974 JP 2000-39730 A JP 2001-040237 A

  An object of the present invention has been made in view of the above circumstances, and is to provide an electrophotographic photoreceptor that achieves a harsh level of ghost images that has never been achieved while maintaining high sensitivity.

  Another object of the present invention is to provide a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

According to the present invention, in an electrophotographic photoreceptor having at least a charge generation layer and a charge transport layer in this order on a conductive support, and the charge transport layer contains a hole transporting material, the electrophotographic photoreceptor The electrophotographic photosensitive member is characterized in that the surface layer has a universal hardness of 230 N / mm ² or more, and the charge generation layer contains a charge generation material and an electron transporting material.

  According to the present invention, there are provided a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

  As described above, according to the present invention, an electrophotography that counters a phenomenon in which a portion exposed to light at the time of the previous rotation becomes darker than the other portion at the next rotation, a so-called positive ghost or a phenomenon in which the portion becomes thinner, a so-called negative ghost. An electrophotographic photosensitive member that achieves a ghost level that satisfies a severe image level represented by a color image in a main body without pre-exposure, particularly a main body without pre-exposure, a process cartridge having the electrophotographic photosensitive member, and electrophotography It became possible to supply the device.

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

  1A to 1D are schematic views showing cross-sectional views of the electrophotographic photosensitive member of the present invention. In FIG. 1A, the charge generation layer 1 is provided on the conductive support 3, and the charge transport layer 2 is provided thereon. In FIG. 1B, the subbing is applied on the conductive support 3. In (c), a conductive layer 5 and an undercoat layer 4 are provided on the conductive support 3, and in (d), on the surface layer of (c). A protective layer 6 is provided. You may provide a protective layer on the surface layer of Fig.1 (a) and (b).

  As the conductive support, metals such as aluminum, nickel, chromium, and stainless steel; thin films such as aluminum, nickel, chromium, stainless steel, gold, vanadium, tin oxide, indium oxide, and indium tin oxide (ITO) were provided. And plastic film and the like; and paper coated with or impregnated with a conductivity-imparting agent, and plastic film. These conductive supports are used in an appropriate shape such as a drum shape, a sheet shape, and a plate shape, but are not limited to these shapes.

  Furthermore, various treatments can be performed on the surface of the conductive support as necessary. For example, a metal salt compound or a fluorine compound metal salt is added to an acidic aqueous solution mainly composed of alkaline phosphate or phosphoric acid or tannic acid on the surface of the conductive support or the oxidation treatment such as honing, composite electropolishing and anodization. Chemical treatment that performs chemical treatment with a solution obtained by dissolution, and irregular reflection treatment such as coloring treatment or graining can be performed. Although it does not specifically limit regarding the thickness of an electroconductive support body, 0.2 mm-10 mm are preferable and 0.5 mm-1.5 mm are more preferable.

  A conductive layer can be provided between the support and the undercoat layer. This layer also has a role of covering the protrusions and scratches of the conductive support and a role of preventing interference fringes when an image input such as a laser beam printer uses a light source such as a laser beam. The conductive layer can be formed using a dispersion liquid in which conductive powder such as carbon black, metal, and metal oxide is dispersed in a binder resin. The film thickness is preferably from 0.1 to 30 μm, more preferably from 0.5 to 20 μm.

  Furthermore, an undercoat layer having an adhesive function can be formed on the conductive layer. Examples of the material for the undercoat layer include polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose, casein, polyurethane, and polyether urethane. These materials are prepared by dissolving in a suitable solvent. By applying this prepared solution, an undercoat layer is formed. The film thickness is preferably from 0.1 to 5 μm, more preferably from 0.3 to 2 μm.

  Examples of the charge generating material used in the present invention include (1) azo pigments such as monoazo, disazo and trisazo, (2) phthalocyanine pigments such as metal phthalocyanine and nonmetal phthalocyanine, and (3) indigo materials such as indigo and thioindigo. Pigments, (4) perylene pigments such as perylene anhydride and perylene imide, (5) polycyclic quinone pigments such as anthraquinone and pyrenequinone, (6) squarylium dyes, (7) pyrylium salts and thiapyrylium salts ( 8) Triphenylmethane dye, (9) inorganic substances such as selenium, selenium-tellurium and amorphous silicon, (10) quinacridone pigment, (11) azulenium salt pigment, (12) cyanine dye, (13) xanthene dye, 14) quinoneimine dye, (15) styryl dye, (16) potassium sulfide Miumu and (17) zinc oxide.

  In particular, metal phthalocyanine pigments are preferred, and among them, oxytitanium phthalocyanine crystals, chlorogallium phthalocyanine crystals, dichlorotin phthalocyanine crystals and hydroxygallium phthalocyanine pigments are preferred, and hydroxygallium phthalocyanine pigments are particularly preferred.

  The oxytitanium phthalocyanine pigment has a Bragg angle (2θ ± 0.2 °) of 9.0 °, 14.2 °, 23.9 ° and 27.1 ° in the characteristic X-ray diffraction using CuKα as a radiation source. Oxytitanium phthalocyanine pigment with strong peaks, Bragg angles (2θ ± 0.2 °) of 9.5 °, 9.7 °, 11.7 °, 15.0 °, 23.5 °, 24.1 ° and Oxytitanium phthalocyanine pigments having a strong peak at 27.3 ° are preferred.

  The chlorogallium phthalocyanine crystal has a Bragg angle (2θ ± 0.2 °) of 7.4 °, 16.6 °, 25.5 ° and 28.2 ° in the characteristic X-ray diffraction using CuKα as a radiation source. Chlorogallium phthalocyanine crystals with strong peaks, chlorogallium phthalocyanine crystals with strong peaks at Bragg angles (2θ ± 0.2 °) of 6.8 °, 17.3 °, 23.6 ° and 26.9 °, and Chlorogallium phthalocyanine crystals having strong peaks at Bragg angles (2θ ± 0.2 °) of 8.7 ° to 9.2 °, 17.6 °, 24.0 °, 27.4 ° and 28.8 ° preferable.

  As a dichlorotin phthalocyanine crystal, in characteristic X-ray diffraction using CuKα as a radiation source, Bragg angles (2θ ± 0.2 °) of 8.3 °, 12.2 °, 13.7 °, 15.9 °, Dichlorotin phthalocyanine crystals with strong peaks at 18.9 ° and 28.2 °, Bragg angles (2θ ± 0.2 °) of 8.5 °, 11.2 °, 14.5 ° and 27.2 ° A dichlorotin phthalocyanine crystal having a strong peak, Bragg angle (2θ ± 0.2 °) of 8.7 °, 9.9 °, 10.9 °, 13.1 °, 15.2 °, 16.3 °, Dichlorotin phthalocyanine crystals with strong peaks at 17.4 °, 21.9 ° and 25.5 ° and Bragg angles (2θ ± 0.2 °) of 9.2 °, 12.2 °, 13.4 ° Dichlorotin with strong peaks at 14.6 °, 17.0 ° and 25.3 ° Phthalocyanine crystals are preferred.

  As the hydroxygallium phthalocyanine crystal, in characteristic X-ray diffraction using CuKα as a radiation source, hydroxy having strong peaks at 7.3 °, 24.9 °, and 28.1 ° of Bragg angles (2θ ± 0.2 °). Gallium phthalocyanine crystals, Bragg angles (2θ ± 0.2 °) of 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 ° and 28.3 ° A hydroxygallium phthalocyanine crystal having a strong peak is preferred.

  Electron transport materials to be added to the charge generation layer include quinones such as benzoquinones, diphenoquinones and polycyclic quinones, carbazoles, fluorene compounds, naphthalene tetracarboxylic acid diimide derivatives, naphthalene tetracarboxylic acid diimidazole derivatives, Perylenetetracarboxylic acid diimide derivatives, perylenetetracarboxylic acid diimidazole derivatives, oxadiazole derivatives, and the like can be used, but are not limited thereto. In particular, a naphthalene tetracarboxylic acid diimide derivative represented by the following formula (1) is more preferable.

In the formula, R ₂ and R ₃ each independently represent a hydrogen atom, a halogen atom, a nitro group, an alkoxy group which may have a substituent or an alkyl group which may have a substituent. R ₁ and R ₄ are each independently an alkyl group which may be interrupted by an ether group, an alkenyl group which may be interrupted by an ether group, a heterocyclic group; an alkyl group, an alkenyl group, a nitro group, a halogen atom or a halogen An aryl group which may have a substituted alkyl group; an aralkyl group which may have an alkyl group, an alkenyl group, a nitro group, a halogen atom or a halogen-substituted alkyl group;

  From the viewpoint of solubility in a solvent, the molecular structure is more preferably an asymmetric system. The reduction potential of the electron transporting material is preferably −0.25 to −0.55 (V), more preferably −0.35 to −0.51 (V). The reduction potential was measured by a three-electrode cyclic voltammetry as follows.

Electrode: Working electrode (platinum electrode), counter electrode (platinum electrode)
Reference electrode saturated calomel electrode (0.1 mol / l KCl-water solution)
Measurement solution Electrolyte: t-butylammonium perchlorate 0.1 mol Measurement substance: Electron-transporting material 0.001 mol Solvent: Acetonitrile 1 liter The above was prepared to prepare a measurement solution.

  The peak top of the first reduction potential of the measurement result was taken as the reduction potential of the electron transport material. In addition, when added to the charge generation layer, the LUMO level of the electron transport material is preferably in the range of ± 0.2 (eV) of the LUMO level of the charge generation material in relation to the charge generation material, More preferably, it is in the range of ± 0.1 (eV). Regarding addition of the electron transport material to the charge generation layer solution, it is preferable to add the charge generation material and the binder resin after dispersing them in a solvent. There is a production method in which an electron transporting substance is added during the pigmentation process of the charge generating material, and there are many methods in the vicinity of the charge generating material and less in the binder resin, but the electrons move after receiving the electrons from the charge generating material. Since it is necessary for the binder resin to also have an electron transporting substance, it is preferable to add the electron transporting substance after dispersing the charge generating material and the binder as described above. The addition amount of the electron transporting substance is preferably 7.5 to 60% by mass (hereinafter, mass% is expressed as%), more preferably 25 to 45%, and more preferably 25 to 35% with respect to the charge generation material. Is more preferable. Moreover, for the said reason, 15-120% is preferable also with respect to binder resin, Furthermore, 51-80% is preferable and 51-70% is more preferable. The dispersed particle size of the charge generating material is preferably 0.01 to 0.5 μm, more preferably 0.1 to 0.3 μm.

  As binder resin, butyral resin, polyester resin, polycarbonate resin, polyarylate resin, polystyrene resin, polyvinyl methacrylate resin, polyvinyl acrylate resin, polyvinyl acetate resin, polyvinyl chloride resin, polyamide resin, polyurethane resin, silicone resin, alkyd resin , Epoxy resin, cellulose resin, melamine resin, and the like, but are not limited thereto. In particular, a butyral resin is preferred. This mixed solution is applied onto the undercoat layer and dried to obtain a charge generation layer. The thickness of the charge generation layer is preferably from 0.01 to 2 μm, more preferably from 0.05 to 0.3 μm.

  The charge transport layer is formed by applying and drying a paint prepared by dissolving a charge transport material and a binder resin in a solvent. Examples of the charge transport material include various triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, triallylmethane compounds, and thiazole compounds.

As the binder resin, the resins listed in the charge generation layer can be used, and are not particularly limited. Among them, when the charge transport layer is used for the surface layer, the surface hardness is 230 N / in universal hardness. It is necessary to select a resin and adjust the amount of addition so that it is at least ² mm. A preferred resin is polyarylate resin.

  Specific examples of the repeating structural unit of the polyarylate resin are listed in Table 1. However, these structures may be used alone or may be a copolymer of two or more of these, and is not limited to these structures.

  Among these polyarylate resins, bisphenol C type polyarylate resins, biphenyl type polyarylate resins and copolymers thereof having a repeating structural unit represented by (1-2) are particularly preferred. The mass ratio (D / B) between the charge transport material (D) and the binder resin (B) is preferably 10/5 to 5/10, more preferably 10/8 to 6/10.

  In addition to the charge transport layer, antioxidants such as hindered phenols and hindered amines, lubricating materials such as silicone oil, silicone oil particles, and fluorine atom-containing resin particles, and film strength reinforcing materials such as silica balls are added. May be. A coating liquid containing these is applied onto the charge generation layer and dried to obtain a charge transport layer. The film thickness of the charge transport layer is preferably 5 to 30 μm, and more preferably 8 to 19 μm.

  The weight average molecular weight of the binder resin is preferably 50,000 to 250,000, and more preferably 100,000 to 200,000. The measurement of a weight average molecular weight (Mw) measured molecular weight distribution using the gel permeation chromatography ("HLC-8120" by Tosoh Corporation), and computed it by polystyrene conversion.

For the measurement, tetrahydrofuran (THF) was used as a developing solvent, and a 0.1 mass% solution of a resin sample was used as a column with an exclusion limit molecular weight (polystyrene conversion) 4 × 10 ⁶ column (“TSKgel SuperHM-N” manufactured by Tosoh Corporation). ”), Using RI as a detector, under conditions of a column temperature of 40 ° C., an injection amount of 20 μl, and a flow rate of 1.0 ml / min.

  Furthermore, a surface protective layer may be formed on the charge transport layer. The surface protective layer contains a curable resin and at least one of conductive particles or a charge transport material.

  Examples of the conductive particles used for the protective layer include metals, metal oxides, and carbon black. Examples of the metal include aluminum, zinc, copper, chromium, nickel, silver, and stainless steel, or those obtained by depositing these metals on the surface of plastic particles. Examples of the metal oxide include zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, indium oxide doped with tin, tin oxide doped with antimony and tantalum, and zirconium oxide doped with antimony. . These can be used alone or in combination of two or more. When two or more types are used in combination, they may be simply mixed, or may be in the form of a solid solution or fusion.

  The average particle size of the conductive particles used in the present invention is preferably 0.3 μm or less, particularly preferably 0.1 μm or less, from the viewpoint of the transparency of the protective layer. Moreover, in this invention, it is especially preferable to use a metal oxide from the point of transparency among the electroconductive particle mentioned above.

  As the charge transport material used for the surface protective layer, the same charge transport materials as those used for the charge transport layer described above can be used, and further, hydroxyalkyl represented by the following formulas (3) to (5): The charge transport material having at least one substituent selected from a group and a hydroxyalkoxy group, or the charge transport material having at least one phenolic residue represented by the following formulas (6) to (8) is preferable.

In the formula, R ₁₁ , R ₁₂ and R ₁₃ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and α, β and γ each have a halogen atom or a substituent as a substituent. An optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted aryl group or an optionally substituted heterocyclic group A ring is represented, a, b and d are 0 or 1, and m and n are 0 or 1.

In the formula, R ₁₄ , R ₁₅ and R ₁₆ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and δ and ε each have a halogen atom or a substituent as a substituent. An alkyl group that may have a substituent, an alkoxy group that may have a substituent, an aryl group that may have a substituent, or a benzene ring that may have one or more heterocyclic groups that may have a substituent. E, f and g are 0 or 1. p, q, and r are 0 or 1, and all do not become 0 at the same time. Z ₁ and Z ₂ each have a halogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryl group which may have a substituent, or a substituent. A good heterocyclic group may be indicated and a ring may be formed jointly.

In the formula, R ₁₇ , R ₁₈ , R ₁₉ and R ₂₀ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and ζ, η, θ and ι each represent a halogen atom as a substituent. , An alkyl group that may have a substituent, an alkoxy group that may have a substituent, an aryl group that may have a substituent, or one or more heterocyclic groups that may have a substituent. Benzene ring which may be substituted, h, i, j and k are 0 or 1, and s, t and u are 0 or 1. Z ₃ and Z ₄ each have a halogen atom, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, an aryl group that may have a substituent, or a substituent. A good heterocyclic group may be indicated and a ring may be formed jointly.

In the formula, R ₂₁ represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and R ₂₂ may have a hydrogen atom, an alkyl group which may have a substituent, or a substituent. The phenyl group which may have a good aralkyl group or a substituent is shown. Ar ₁ and Ar ₂ are an alkyl group that may have a substituent, an aralkyl group that may have a substituent, an aryl group that may have a substituent, or a heterocyclic group that may have a substituent. Indicates. Ar ₃ represents an arylene group which may have a substituent or a heterocyclic group which may have a divalent substituent. v and w are 0 or 1, respectively. However, when w = 0, v = 0. κ and λ each have a halogen atom as a substituent, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, an aryl group that may have a substituent, or a substituent. And a benzene ring which may have one or more heterocyclic groups.

In the formula, R ₂₃ represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched. Ar ₄ and Ar ₅ are an alkyl group that may have a substituent, an aralkyl group that may have a substituent, an aryl group that may have a substituent, or a heterocyclic group that may have a substituent. Indicates. μ and ν each have a halogen atom as a substituent, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, an aryl group that may have a substituent, or a substituent. And a benzene ring which may have one or more heterocyclic groups. Μ and ν may form a ring jointly via a substituent. x is 0 or 1.

In the formula, R ₂₄ and R ₂₅ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched. Ar ₆ represents an alkyl group that may have a substituent, an aralkyl group that may have a substituent, an aryl group that may have a substituent, or a heterocyclic group that may have a substituent. ξ, π, ρ and σ are each a halogen atom as a substituent, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, an aryl group that may have a substituent, or a substituent A benzene ring which may have one or more heterocyclic groups which may have Note that ξ and π, and ρ and σ may form a ring jointly via a substituent. y and z are 0 or 1, respectively.

  The resin that can be polymerized and cross-linked by light irradiation or light such as UV may be any compound that can generate an active site such as a radical by light irradiation or light such as UV and can be polymerized or cross-linked. In general, a compound having a chain polymerizable functional group is exemplified. Among them, a compound having an unsaturated polymerizable functional group in the molecule is preferable from the viewpoint of high reactivity, fast reaction rate, versatility of materials, etc., and acryloyloxy group, methacryloyloxy group and styrene group are particularly preferable. These are not limited to any of monomers, oligomers, macromers and polymers, and can be appropriately selected or combined. In addition, in the case of using a resin having charge transporting ability, preferably hole transporting ability and capable of being polymerized and cross-linked by irradiation with radiation or light such as UV, a charge transport layer is formed by itself or the above-mentioned charge transport It is possible to appropriately mix a material and a resin that can be polymerized and cross-linked by irradiation with radiation that does not have charge transporting ability or light such as UV. Resins that have charge transporting ability and can be polymerized and cross-linked by irradiation with radiation or light such as UV are, for example, known hole transporting compounds having an unsaturated polymerizable functional group, and known hole transporting compounds. What is necessary is just the compound etc. which added the unsaturated polymerizable functional group to the part. Examples of known hole transporting compounds include hydrazone compounds, pyrazoline compounds, triphenylamine compounds, benzidine compounds, and stilbene compounds, but any compounds can be used as long as they are hole transporting compounds. Furthermore, in the present invention, in order to sufficiently secure the hardness of the electrophotographic photoreceptor surface layer, the compound having an unsaturated polymerizable functional group is a compound having a plurality of unsaturated polymerizable functional groups in one molecule. Is preferred.

  The lubricating resin used in the surface layer of the present invention includes fluorine atom-containing resin particles, silica particles, and silicone particles. In the present invention, fluorine atom-containing resin particles are particularly preferable. Examples of the fluorine atom-containing resin particles used in the present invention include ethylene tetrafluoride, ethylene trifluoride chloride resin, hexafluoroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin and Among these copolymers, it is preferable to select one or two or more types as appropriate, and ethylene tetrafluoride resin and vinylidene fluoride resin are particularly preferable. The molecular weight of the resin particles and the particle size of the particles can be appropriately selected and are not particularly limited.

  As the binder resin for the protective layer, a curable resin is more preferable from the viewpoint of high surface hardness and excellent wear resistance. Examples of the curable resin include, but are not limited to, an acrylic resin, a urethane resin, an epoxy resin, a silicone resin, and a phenol resin. In the present invention, an acrylic resin or a phenol resin is preferable.

  The above resin is a resin containing a monomer or oligomer that is cured by heat, light, electron beam or the like. A monomer or oligomer that is cured by heat, light, or electron beam has, for example, a functional group that causes a polymerization reaction at the end of the molecule by energy such as heat or light. A relatively large molecule of about 20 is an oligomer, and a smaller molecule is a monomer. Examples of the functional group causing the polymerization reaction include those having a carbon-carbon double bond such as acryloyl group, methacryloyl group, vinyl group and acetophenone group, silanol group, and ring-opening polymerization such as cyclic ether group, or Examples thereof include those in which two or more kinds of molecules react to cause polymerization, such as phenol + formaldehyde.

  In the case of a protective layer containing a charge transport material, the charge transport material used may be a hydrazone compound, a styryl compound, an oxazole compound, a thiazole compound, a triarylmethane compound, a polyarylalkane compound, or the like. However, it is not limited to these. The solvent of the protective layer solution is preferably a solvent that does not adversely affect the charge transporting layer that is in contact with it. Therefore, the solvents include alcohols such as methanol, ethanol and 2-propanol, ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, ethers such as tetrahydrofuran and dioxane, and aromatics such as toluene and xylene. Aromatic hydrocarbons, halogenated hydrocarbons such as chlorobenzene and dichloromethane can be used. Among these, even in the dip coating method having good productivity, the best solvents are alcohols such as methanol, ethanol, and 2-propanol.

  The protective layer in the present invention preferably uses a curable resin. The curing type includes a thermosetting type, a photocuring type, and a radiation curing type, but is not dependent on the type of curing. When the type of curing is a thermosetting type, it is usually cured in a hot air drying oven after the protective layer is applied on the photosensitive layer. The curing temperature at this time is preferably 100 ° C to 300 ° C, more preferably 120 ° C to 200 ° C. Moreover, the film thickness of the protective layer is preferably 0.5 μm to 10 μm, more preferably 1 μm to 7 μm.

  When the type of curing is radiation, as disclosed in JP-A-2000-066425, examples include electron beams and γ-rays, and various types of apparatus such as size, safety, cost, and versatility. From the viewpoint, an electron beam is preferable. In the case of electron beam irradiation, any of a scanning type, an electro curtain type, a broad beam type, a pulse type, a laminar type, or the like can be used as an accelerator. In the present invention in which an electrophotographic photosensitive member is formed by electron beam irradiation, the acceleration voltage and absorbed dose of the electron beam are very important factors in fully expressing the electric characteristics and durability of the electrophotographic photosensitive member. The acceleration voltage is preferably 300 KV or less, optimally 150 KV or less, and the dose is preferably in the range of 1 to 100 Mrad, more preferably 50 Mrad or less. When the acceleration voltage exceeds 300 KV or the dose exceeds 100 Mrad, the electrophotographic photosensitive member tends to deteriorate.

  Examples of the method for applying these photosensitive layers include dip coating, spray coating, spinner coating, bead coating, blade coating, and beam coating. The dip coating method is more preferable from the viewpoint of mass productivity.

The electrostatic capacity per 1 cm ^{2 of the} electrophotographic photosensitive member is preferably 135 pF / cm ² or more. Furthermore, 150 pF / cm ² or more is preferable, and 400 pF / cm ² or less is particularly preferable. The electrostatic capacity of the electrophotographic photosensitive member is determined by all the layers of the photosensitive layer, and has a slight influence on the relationship between the layers. Among the layer configurations, the charge transport layer has the largest ratio of controlling the capacitance among the film configurations of the electrophotographic photosensitive member. Among them, the relative dielectric constant ε of the binder resin and the thickness of the charge transport layer are large. Influence. The relative dielectric constant of the binder resin of the charge transport layer is preferably 2.6 to 3.5, and more preferably 2.8 to 3.2. The capacitance is measured by preparing an electrode of a certain area on the surface of the electrophotographic photosensitive member by gold sputtering or the like, and using an impedance measuring instrument (4192A, manufactured by YHP Co., Ltd.), the static when the frequency is 1 kHz. The area of the electrode was divided from the measured capacitance value to obtain a measured capacitance value per 1 cm ² . With respect to a sample having a curvature, for example, it is cut into about 2 cm square, and a 1 cm ² electrode can be produced by gold sputtering and measured. In some cases, the instrument may need some modifications.

  The universal hardness of the present invention was measured using a hardness meter Fischerscope H100V (manufactured by Fischer, Germany) in an environment of 23 ° C./45% RH. In the measurement, a diamond indenter having a quadrangular pyramid shape and a facing angle of 136 ° was used, and a set load was applied stepwise to the surface of the electrophotographic photosensitive member when the load was applied. The indentation depth is electrically detected and read, indented to 1 μm, and the hardness value H is displayed as a ratio obtained by dividing the test load by the surface area of the indentation generated by the test load. In the universal hardness, the value of Hu is represented by the hardness value at the set maximum indentation depth.

  As shown in FIG. 2, the elastic deformation rate We% is obtained from the elastic deformation work We (nJ) and the plastic deformation work Wr (nJ) using the following mathematical formula (II). The measurement was performed 10 times while changing the measurement position on the same sample, and the average was obtained from 8 points excluding the maximum and minimum values.

  Elastic deformation ratio We% = elastic deformation work We / (elastic deformation work We + plastic deformation work Wr) × 100... Formula (II)

  FIG. 5 shows a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

  In FIG. 5, reference numeral 11 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is rotationally driven around a shaft 12 at a predetermined peripheral speed (process speed) in the arrow direction. In the rotation process, the electrophotographic photosensitive member 11 is subjected to uniform charging at a predetermined positive or negative potential on the peripheral surface thereof by the primary charging means 13, and then subjected to slit exposure or laser beam scanning exposure which is reflected light from the original. The exposure light 14 intensity-modulated in response to the time-series electric digital image signal of the target image information output from the exposure means (not shown) is received. In this way, electrostatic latent images corresponding to target image information are sequentially formed on the peripheral surface of the electrophotographic photosensitive member 11.

  The formed electrostatic latent image is visualized as a transferable particle image (toner image) by regular development or reversal development with charged particles (toner) in the developing means 15, and is electrophotographic from a paper supply unit (not shown). A toner image formed and supported on the surface of the electrophotographic photosensitive member 11 is transferred to the transfer material 17 that is taken out and fed between the photosensitive member 11 and the transfer unit 16 in synchronization with the rotation of the electrophotographic photosensitive member 11. The images are sequentially transferred by the transfer means 16. At this time, a bias voltage having a polarity opposite to the charge held in the toner is applied to the transfer means from a bias power source (not shown).

  The transfer material 17 that has received the transfer of the toner image (in the case of the final transfer material (paper, film, etc.)) is separated from the electrophotographic photosensitive member surface, conveyed to the fixing means 18, and undergoes a toner image fixing process. Printed out of the apparatus as a formed product (print, copy). When the transfer material 17 is a primary transfer material (intermediate transfer material or the like), it is printed out after a fixing process after a plurality of transfer processes.

  The surface of the electrophotographic photosensitive member 11 after the toner image is transferred is cleaned by the cleaning means 19 after removal of deposits such as toner remaining after transfer. In recent years, a cleanerless system has been studied, and the transfer residual toner can be directly collected by a developing device or the like.

  In the present invention, a plurality of components such as the electrophotographic photosensitive member 11, the primary charging unit 13, the developing unit 15 and the cleaning unit 19 are housed in a container and integrally combined as a process cartridge. The process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. For example, at least one of the primary charging unit 13, the developing unit 15, and the cleaning unit 19 is integrally supported together with the electrophotographic photosensitive member 11 to form a cartridge, and is attached to and detached from the apparatus main body using a guide unit 21 such as a rail of the apparatus main body. A flexible process cartridge 20 can be obtained.

  Further, when the electrophotographic apparatus is a copying machine or a printer, the exposure light 14 is a reflected light or transmitted light from a document, or a signal is read by a document by a sensor, and a laser beam scanning performed according to this signal is performed. The light emitted by driving the LED array or the liquid crystal shutter array.

  The electrophotographic photosensitive member of the present invention can be used not only for electrophotographic copying machines but also widely applicable to electrophotographic application fields such as laser beam printers, CRT printers, LED printers, FAX, liquid crystal printers, and laser plate making. It is.

  The basic configuration of the electrophotographic apparatus of the present invention, especially a full-color machine, usually has four such configurations, each of which is a tandem system or an electrophotographic photosensitive member arranged in four colors of magenta, cyan, yellow, and black. In contrast, there are four developing units, and there are two sets of developing units for two colors for one drum.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, embodiments of the present invention are not limited to these. In the examples, “part” means “part by mass”.

(Example 1)
A honed-treated aluminum cylinder with a diameter of 30 mm x 260.5 mm is used as a support, and 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon are dissolved in a mixed solvent of methanol 65 / n-butanol 30 parts. The resulting solution was applied by a dip coating method and dried at 90 ° C. for 5 minutes to form an undercoat layer having a thickness of 0.5 μm.

  Next, as shown in FIG. 3, hydroxygallium phthalocyanine having strong peaks at 7.4 °, 25.0 ° and 28.2 ° of the Bragg angle (2θ ± 0.2 °) in the characteristic X-ray diffraction of CuKα. 2 parts of crystals and 1 part of polyvinyl butyral resin (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) are added to 120 parts of cyclohexanone and dispersed in a sand mill using 1 mmφ glass beads for 3 hours. Part was added to dilute. In this mixed solution, 0.6 part of a tetracarboxylic acid diimide derivative represented by the following formula (9) was dissolved to prepare a charge generation layer coating solution. The reduction potential of the compound represented by the formula (9) was −0.47 (V). The dispersed particle diameter of CAPA-700 (manufactured by Horiba, Ltd.) of the charge generating material at this time was 0.15 μm. On the undercoat layer, this charge generation layer coating solution was applied by dip coating and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.15 μm.

  Next, 7 parts of a compound represented by the following formula (10),

下記式（１１）で示される化合物１部、

1 part of a compound represented by the following formula (11),

及び、表１の（１−２）で示される繰り返し構造単位を有するビスフェノールＣ型ポリアリレート樹脂（樹脂中におけるテレフタル酸とイソフタル酸の質量比：テレフタル酸／イソフタル酸＝５０／５０）１０部をモノクロロベンゼン５０部／ジクロロメタン１０部の混合溶媒に溶解し、電荷輸送層用塗料を調製した。この塗料を電荷発生層上に浸漬塗布法で塗布し、１１０℃で１時間乾燥して、膜厚が１７μｍの電荷輸送層を形成した。こうして電子写真感光体を作製した。

And 10 parts of a bisphenol C-type polyarylate resin having a repeating structural unit represented by (1-2) in Table 1 (mass ratio of terephthalic acid to isophthalic acid in the resin: terephthalic acid / isophthalic acid = 50/50) It was dissolved in a mixed solvent of 50 parts of monochlorobenzene / 10 parts of dichloromethane to prepare a charge transport layer coating material. This paint was applied on the charge generation layer by a dip coating method and dried at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 17 μm. Thus, an electrophotographic photosensitive member was produced.

  Preparation of the bisphenol C type polyarylate resin which has a repeating structural unit shown by following formula (12) is obtained as follows.

Add 0.3 mol each of bisphenol C monomer, 0.012 mol of pt-butylphenol as molecular weight regulator and 65 g of sodium hydroxide in 2 liters of ion-exchanged water, then add phase transfer catalyst tributylbenzylammonium chloride. Dissolved (aqueous phase). Separately, 0.64 mol of a 1: 1 mixture of terephthalic acid chloride and isophthalic acid chloride was dissolved in 1 liter of dichloromethane (organic phase). The reaction vessel was kept at 20 ° C., the organic phase was added to the aqueous phase with strong stirring, and interfacial polymerization was performed for 4 hours. Although there was a polymer formed in the organic phase, this organic phase was thoroughly washed with ion-exchanged water in order to prevent the catalyst from being mixed into the polymer. In addition, the organic phase was added dropwise to methanol to reprecipitate and isolate the polymer. The weight average molecular weight (Mw) of the obtained polymer was 11.5 × 10 ⁴ . Other polyarylate resins can be synthesized in the same manner.

The universal hardness of the surface layer at this time was 235 N / mm ² and the elastic deformation rate was 43.6%. Further, the electrostatic capacity of this electrophotographic photosensitive member was 158 pF / cm ² . The relative dielectric constant of only the charge transport layer resin was 3.15.

  As an evaluation method, the produced electrophotographic photosensitive member is a color laser printer manufactured by Hewlett-Packard Co., Ltd., laser jet 4600 (primary charging: roller contact DC charging, one-component contact development, process speed 94.2 mm / second, laser The ghost image was evaluated immediately after the endurance of 5000 sheets in a 10% image density image in an environment of 13 ° C./5% RH with the pre-exposure removed. The ghost image is produced with a single color of magenta, cyan, yellow, and black. For example, in the case of black, as shown in FIG. A halftone image printed with a pattern was prepared. The order of image production is to take a solid white image as the first image, then take five consecutive ghost images, then take one solid black image and then take five ghost images again for a total of ten images. Evaluation was performed using a ghost image. The evaluation of the ghost image is performed by measuring the density difference between the image density obtained by printing one dot in the Keima pattern and the image density of the ghost portion with a spectral densitometer X-Rite 504/508 (manufactured by X-Rite Co., Ltd.). Ten points were measured on the ghost image, and the average of those ten points was taken as one result, and all the above-mentioned ten ghost images were measured in the same manner. Their average value was determined. By this method, the other three colors were similarly processed, and evaluation was performed using an average value of these values. As the measurement result of each color, the result of each color of magenta, cyan, yellow, and black of the spectral densitometer X-Rite is displayed, and the value of the same color as the image color is used as the measurement value. Moreover, this density difference means that the smaller the value, the better the ghost.

(Example 2)
In Example 1, the charge transport layer binder is a bisphenol C type polyarylate resin having a repeating structural unit represented by (1-2) in Table 1 (mass ratio of terephthalic acid to isophthalic acid in the resin: terephthalic acid / isophthalic acid). Acid = 50/50) and a biphenyl polyarylate resin having a repeating structural unit represented by (1-14) (mass ratio of terephthalic acid to isophthalic acid in the resin: terephthalic acid / isophthalic acid = 50/50) Except for changing to a polyarylate copolymer resin (weight average molecular weight Mw: 13.5 × 10 ⁴ ) having a molar fraction of 7/3, and changing the film thickness of the charge transport layer to 10 μm, completely the same as Example 1. The same was done.

The universal hardness of the surface layer at this time was 250 N / mm ² and the elastic deformation rate was 45.2%. The electrostatic capacity of this electrophotographic photosensitive member was 268 pF / cm ² . The relative dielectric constant of only the binder of the charge transport layer was 3.20.

(Example 3)
In Example 1, it changed as follows.

An aluminum ED cylinder is used as a support, and on this, 10 parts of conductive tin oxide-coated barium sulfate as a conductive pigment, 2 parts of titanium oxide as a resistance adjusting pigment, and a phenol resin as a binder resin (J325: DIC Corporation) 6 parts), 0.001 part of silicone oil as leveling agent, 0.2 part of Tospearl as interference fringe prevention, and methanol / methoxypropanol = 4/6 20 parts as a solvent were applied by a dip coating method. Thermal curing was performed at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm. A subbing layer was applied thereon as in Example 1. The electron transport material added to the charge generation layer was 0.5 part of the compound represented by the following formula (13). The reduction potential of the compound represented by the formula (13) was −0.51 (V). The binder of the charge transport layer is a bisphenol Z-type polyarylate resin having a repeating structural unit represented by (1-9) in Table 1 (mass ratio of terephthalic acid to isophthalic acid in the resin: terephthalic acid / isophthalic acid = 50/50 ) And a biphenyl-type polyarylate resin having a repeating structural unit represented by (1-12) (mass ratio of terephthalic acid to isophthalic acid in the resin: terephthalic acid / isophthalic acid = 50/50) is 6 The thickness of the charge transport layer was changed to 19 μm by changing to a polyarylate copolymer resin (weight average molecular weight Mw: 1.05 × 10 ⁵ ) to be / 4. Except for the changes described above, the procedure was the same as in Example 1.

The universal hardness of the surface layer at this time was 238 N / mm ² and the elastic deformation rate was 39.2%. The electrostatic capacity of this electrophotographic photosensitive member was 138 pF / cm ² . The relative dielectric constant of only the binder of the charge transport layer was 3.12.

Example 4
In Example 3, the addition amount of the electron transport material in the charge generation layer is 0.7 part, the weight average molecular weight of the binder of the charge transport layer is 20.0 × 10 ⁴ , and the thickness of the charge transport layer is 8 μm. The procedure was the same as in Example 3 except that

The universal hardness of the surface layer at this time was 258 N / mm ² and the elastic deformation rate was 41.3%. The relative dielectric constant of only the binder of the charge transport layer was 3.12, which was the same as in Example 3. The electrostatic capacity of this electrophotographic photosensitive member was 332 pF / cm ² .

(Example 5)
In Example 3, the binder in the charge transport layer is a bisphenol A type polyarylate resin having a repeating structural unit represented by (1-1) in Table 1 (mass ratio of terephthalic acid and isophthalic acid in the resin: terephthalic acid / Isophthalic acid = 50/50) and a biphenyl type polyarylate resin having a repeating structural unit represented by (1-15) (mass ratio of terephthalic acid to isophthalic acid in the resin: terephthalic acid / isophthalic acid = 50/50) Is changed to a polyarylate copolymer resin (weight average molecular weight Mw: 8.0 × 10 ⁴ ) with a molar fraction of 8/2, and the primary charging of the laser jet 4600 of the evaluator is superimposed on the DC voltage with the AC voltage The procedure was the same as in Example 3 except that the above was changed. At this time, the AC peak-to-peak voltage was 1.8 kV, and the frequency was 870 Hz. The universal hardness of the surface layer at this time was 230 N / mm ² and the elastic deformation rate was 38.0%. The relative dielectric constant of only the binder in the charge transport layer was 3.05. The electrostatic capacity of this electrophotographic photosensitive member was 137 pF / cm ² .

(Example 6)
In Example 5, the same procedure as in Example 3 was performed except that the primary charger was remodeled so that a corona charger could be attached, and the primary charging was performed by the corona charger.

(Example 7)
In Example 5, the charge generation material of the charge generation layer was 9.5 °, 9.7 °, 11.7 °, 15.0 ° with a Bragg angle (2θ ± 0.2) in the characteristic X-ray diffraction of CuKα, The oxytitanium phthalocyanine pigment having strong peaks at 23.5 °, 24.1 ° and 27.3 ° is used, and the electron transporting material is a material represented by the following formula (14). Changed to 0.4 parts. The particle size of the charge generation material in the charge generation layer solution at this time was 0.12 μm. Further, the thickness of the charge transport layer was set to 19.5 μm. The same procedure as in Example 5 was performed except for the above changes. The reduction potential of the compound represented by the formula (14) was −0.58 (V). The values of universal hardness, elastic deformation rate, etc. were the same as in Example 5, and the electrostatic capacity of the electrophotographic photosensitive member was 135 pF / cm ² .

(Example 8)
In Example 7, it carried out like Example 7 except having changed the electron carrying material in a charge transport layer into the material shown by following formula (15). The reduction potential of the compound represented by the formula (15) was −0.24 (V). The values of universal hardness, elastic deformation rate, etc. were the same as in Example 7, and the electrostatic capacity of the electrophotographic photosensitive member was 135 pF / cm ² .

Example 9
In Example 7, as an undercoat layer coating solution on an aluminum cylinder, titanium dioxide: 10 parts, polyester resin (trade name: Byron 200, manufactured by Toyobo Co., Ltd.): 1 part, toluylene-2,4-diisocyanate: 0.2 parts, 2-butanone: 100 parts, 4-methyl-2-pentanone: 70 parts, and an undercoat layer having a thickness of 2 μm was formed. Further, the electron transport material in the charge generation layer was a material represented by the following formula (16), the addition amount of the electron transport material was changed to 0.67 parts, and the thickness of the charge generation layer was set to 0.2 μm. Furthermore, the charge transport material in the charge transport layer was changed to that shown by the following formula (17), the amount of charge transport material added was 11 parts, and the thickness of the charge transport layer was 18 μm. Except for the changes described above, the procedure was the same as in Example 7.

The universal hardness of the surface layer at this time was 230 N / mm ² and the elastic deformation rate was 38.0%. The electrostatic capacity of this electrophotographic photosensitive member was 148 pF / cm ² .

(Comparative Example 1)
In Example 8, the same operation as in Example 8 was performed, except that no electron transporting material was added to the charge generation layer.

(Comparative Example 2)
In Example 9, the charge generation material is changed to that represented by the following formula (18), the binder is changed to polyvinyl butyral resin (trade name: XYHL, manufactured by UCC Corporation), and the film thickness of the charge generation layer is 0. .3 μm, and the binder in the charge transport layer is a bisphenol A type polyarylate resin having a repeating structural unit shown in (1-1) of Table 1 (trade name: U-100, manufactured by Unitika Ltd .: weight average molecular weight) (Mw) 6.0 × 10 ⁴ ), except that the solvent was changed to tetrahydrofuran.

The universal hardness of the surface layer at this time was 205 N / mm ² and the elastic deformation rate was 36.5%. The relative dielectric constant of only the binder of the charge transport layer was 3.01. The electrostatic capacity of this electrophotographic photosensitive member was 145 pF / cm ² .

(Comparative Example 3)
In Comparative Example 2, the same procedure as in Comparative Example 2 was performed except that the binder resin in the charge transport layer was changed to a bisphenol A type polycarbonate resin (trade name: Panlite L-1250, manufactured by Teijin Chemicals Ltd.). .

The universal hardness of the surface layer at this time was 195 N / mm ² and the elastic deformation rate was 35.7%. The electrostatic capacity of this electrophotographic photosensitive member was 144 pF / cm ² . The relative dielectric constant of only the binder of the charge transport layer was 2.95.

(Comparative Example 4)
In Comparative Example 2, exactly the same as Comparative Example 2 except that the binder resin in the charge transport layer was changed to a polyester resin (trade name: Byron 200, manufactured by Toyobo Co., Ltd .: weight molecular weight 1.7 × 10 ⁴ ). went.

At this time, the universal hardness of the surface layer was 185 N / mm ² and the elastic deformation rate was 35.0%. The electrostatic capacity of this electrophotographic photosensitive member was 152 pF / cm ² . The relative dielectric constant of only the binder of the charge transport layer was 3.22.

(Example 10)
In Example 7, the following changes were made. Oxytitanium phthalocyanine crystal having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° of the Bragg angle (2θ ± 0.2 °) in the characteristic X-ray diffraction of CuKα 3 parts and 2 parts of polyvinyl butyral resin (trade name: ESREC BM-2, manufactured by Sekisui Chemical Co., Ltd.) and 0.6 part of a compound represented by the following formula (19) are added to 80 parts of cyclohexanone, and 1 mmφ glass beads For 4 hours, 115 parts of methyl ethyl ketone was added thereto and diluted to prepare a coating solution for charge generation layer. The reduction potential of the compound represented by the formula (19) was −0.51 (V). At this time, the dispersed particle diameter of the charge generating material was 0.10 μm. On the undercoat layer, this charge generation layer coating solution was applied by dip coating and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm. In addition, t-Bu in the following formula (19) represents a tertiary butyl group.

Next, 10 parts of the compound represented by the formula (10) was used as the charge transport layer, and after coating on the charge generation layer, it was dried at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 20 μm. Thus, an electrophotographic photosensitive member was produced. The same procedure as in Example 7 was performed except for the above changes. The electrostatic capacity of this electrophotographic photosensitive member was 128 pF / cm ² .

(Comparative Example 5)
In Example 10, the addition amount of the electron transporting material in the charge generation layer was changed to 0.03 part, and the binder in the charge transport layer was bisphenol Z-type polycarbonate (trade name: Z200, manufactured by Mitsubishi Gas Chemical Co., Ltd .: The procedure was the same as in Example 10, except that the weight average molecular weight was changed to 5.0 × 10 ⁴ ).

At this time, the universal hardness of the surface layer was 200 N / mm ² and the elastic deformation rate was 42%. The electrostatic capacity of this electrophotographic photosensitive member was 128 pF / cm ² . The relative dielectric constant of only the binder of the charge transport layer was 2.95.

(Comparative Example 6)
In Example 10, the same operation as in Example 10 was performed, except that no electron transporting material was added to the charge generation layer.

(Example 11)
In Example 7, the following changes were made. Using a 30 mmφ × 260.5 mm aluminum cylinder as a support, 10 parts of a zirconium compound (trade name: Olga Chix ZC540, manufactured by Matsumoto Pharmaceutical Co., Ltd.) and 1 part of a silane compound (trade name: A1110, manufactured by Nippon Junker Co., Ltd.) A solution dissolved in a mixed solvent of 40 parts of propanol / 20 parts of butanol was applied by a dip coating method and dried by heating at 150 ° C. for 10 minutes to form an undercoat layer having a thickness of 0.5 μm.

  Next, 1 part of an X-type metal-free phthalocyanine crystal and 0.2 part of a compound represented by the following formula (20) were added to 1 part of a polyvinyl butyral resin (trade name: ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.) and n-acetate. After mixing with 100 parts of butyl and dispersing with glass beads for 1 hour in a paint shaker, the resulting dispersion was applied onto the undercoat layer by dip coating and dried by heating at 100 ° C. for 10 minutes. In order to match the required sensitivity of the evaluator, a charge generation layer having a thickness of 0.6 μm was formed. The reduction potential of the compound represented by the formula (20) was −0.69 (V). In addition, Octyl in the following formula (20) represents an octyl group.

Next, 2 parts of a compound represented by the following formula (21) and a binder are bisphenol Z-type polyarylate resins having a repeating structural unit represented by (1-10) in Table 1 (mass of terephthalic acid and isophthalic acid in the resin) Ratio: terephthalic acid / isophthalic acid = 50/50) and biphenyl type polyarylate resin having a repeating structural unit represented by (1-13) (mass ratio of terephthalic acid and isophthalic acid in the resin: terephthalic acid / isophthalic acid = 50/50) and 3 parts of a polyarylate copolymer resin (weight average molecular weight Mw: 2 × 10 ⁵ ) having a molar fraction of 7/3 is dissolved in 20 parts of monochlorobenzene. Then, it is applied by dip coating on an aluminum cylinder on which a charge generation layer is formed, and is heated and dried at 120 ° C. for 1 hour to obtain a film thickness of 20 μm. Of to form a charge transport layer.

At this time, the universal hardness of the surface layer was 265 N / mm ² and the elastic deformation rate was 48%. The electrostatic capacity of this electrophotographic photosensitive member was 128 pF / cm ² . The relative dielectric constant of only the binder of the charge transport layer was 2.90.

(Comparative Example 7)
In Example 11, the electron transporting material in the charge generation layer was changed to 0.05 part, and the binder in the charge transport layer was changed to bisphenol Z-type polycarbonate (trade name: Z400, weight average molecular weight 8 × 10 ⁴ ). Except for the above, the same procedure as in Example 11 was performed.

The universal hardness of the surface layer at this time was 210 N / mm ² and the elastic deformation rate was 43%. The electrostatic capacity of this electrophotographic photosensitive member was 130 pF / cm ² . It was a dielectric constant of only the binder of the charge transport layer.

(Comparative Example 8)
In Example 11, the same operation as in Example 11 was performed except that the electron transporting material was not added to the charge generation layer.

(Example 12)
In Example 7, the following changes were made. The thickness of the charge transport layer was 6 μm. Further, a surface protective layer was produced as follows. 100 parts of ethanol using 250 parts of ethanol and 70 parts of a charge transport material represented by the following formula (22) and a resol type phenolic resin (trade name: PL-5294, manufactured by Gunei Chemical Industry Co., Ltd .: using a metal-based alkali catalyst) Part was dissolved. Furthermore, 0.5 parts of powder obtained by purifying a fluorine atom-containing compound (trade name: GF-300, manufactured by Toa Gosei Co., Ltd.) in 20 parts of ethanol, polytetrafluoroethylene particles (trade name: Lubron L-2, Daikin Industries) 9 parts of (made by Co., Ltd.) was dispersed with a paint shaker containing 1 mmφ glass beads for 2 hours, and this was added to the solution in which the above charge transport material and resin were dissolved to form a protective layer solution, which was applied on the charge transport layer. Cured. As the curing conditions, a surface protective layer having a film thickness of 3 μm was prepared by curing at 155 ° C. for 2 hours in a hot air drying oven. Except for the changes described above, the procedure was the same as in Example 7.

At this time, the surface layer had a universal hardness of 295 N / mm ² and an elastic deformation rate of 53%. The electrostatic capacity of this electrophotographic photosensitive member was 290 pF / cm ² .

(Comparative Example 9)
In Example 12, the same operation as in Example 12 was performed except that the electron transporting material in the charge generation layer was not added.

  The results are shown in Table 2.

It is sectional drawing which shows the layer structure of the electrophotographic photoreceptor of this invention. It is an example of a measurement chart in a Fischer hardness meter. 3 is a pattern showing powder X-ray diffraction of a hydroxygallium phthalocyanine crystal used in Example 1. FIG. It is a figure which shows the outline of the ghost image evaluated in the Example. 1 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus including a process cartridge having the electrophotographic photosensitive member of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Charge generation layer 2 Charge transport layer 3 Conductive support body 4 Undercoat layer 5 Conductive layer 6 Protective layer 11 Electrophotographic photosensitive member 12 Shaft 13 Primary charging means (contact charge, non-contact charge (corona charge etc.))
14 Exposure light (laser light, LED, etc.)
15 Development means (contact system, non-contact system, etc.)
16 Transfer means (contact system, non-contact system, etc.)
17 Transfer material 18 Fixing means 19 Cleaning means (may not be present)
20 Process cartridge 21 Guide means

Claims (10)

In an electrophotographic photoreceptor having at least a charge generation layer and a charge transport layer in this order on a conductive support, the charge transport layer containing a hole transporting material, the surface layer of the electrophotographic photoreceptor An electrophotographic photosensitive member having a universal hardness of 230 N / mm ² or more and containing a charge generation material and an electron transporting material in the charge generation layer. The electrophotographic photosensitive member according to claim 1, wherein an elastic deformation rate We (%) of the charge transport layer satisfies the following formula (I).
38 (%) ≦ We (%) ≦ 60 (%) (I) The electrophotographic photosensitive member according to claim 1 or 2 capacitance of 1 cm ² per the electrophotographic photoconductor is 135pF / cm ² or more.   The electrophotographic photosensitive member according to claim 1, wherein the charge generation material in the charge generation layer is a hydroxygallium phthalocyanine pigment. The electrophotographic photosensitive member according to claim 1, wherein the electron transporting material is represented by the following formula (1):

(In the formula, R ₂ and R ₃ each independently represent a hydrogen atom, a halogen atom, a nitro group, an alkoxy group which may have a substituent or an alkyl group which may have a substituent. R ₁ and R ₄ independently represents an alkyl group which may be interrupted by an ether group, an alkenyl group which may be interrupted by an ether group, a heterocyclic group; an alkyl group, an alkenyl group, a nitro group, a halogen atom or a halogen-substituted alkyl group. An aryl group which may have; an alkyl group, an alkenyl group, a nitro group, a halogen atom or a aralkyl group which may have a halogen-substituted alkyl group;   The electrophotographic photosensitive member according to claim 1, wherein the resin used for the charge transport layer is a polyarylate resin. The polyarylate resin is a bisphenol C type polyarylate resin having a repeating structural unit represented by the following formula (2), or a copolymer of the bisphenol C type polyarylate resin and a biphenyl type polyarylate resin. The electrophotographic photoreceptor described in 1.

  The electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photosensitive member has a protective layer containing a curable resin on the charge transport layer.   9. The electrophotographic photosensitive member according to claim 1, charging means for charging the electrophotographic photosensitive member, and development for developing the electrophotographic photosensitive member on which an electrostatic latent image is formed with toner. And at least one means selected from the group consisting of cleaning means for collecting the toner remaining on the electrophotographic photosensitive member after the transfer step are integrally supported and detachable from the main body of the electrophotographic apparatus. Process cartridge characterized by.   9. The electrophotographic photosensitive member according to claim 1, charging means for charging the electrophotographic photosensitive member, and exposure for forming an electrostatic latent image by exposing the charged electrophotographic photosensitive member. And a transfer unit for transferring the toner image on the electrophotographic photosensitive member onto a transfer material. Electrophotographic device.

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