JP2016184004A - Electrophotographic photoreceptor, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor including an outermost surface layer that is hard to be peeled off.SOLUTION: There is provided an electrophotographic photoreceptor 7A that comprises a conductive substrate 4 and photosensitive layers 2, 3 arranged on the conductive substrate, where an outermost surface layer 5 is a hardened film of a composition including a charge transport skeleton having an aromatic ring, and includes a charge transport compound A having a structure in which a [(tetrahydro-2H-pyran-2-yl)oxy]methyl group and a methylol group are coupled to the aromatic ring.SELECTED DRAWING: Figure 1

Description

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

For example, in Patent Document 1, “in an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support, the outermost surface layer of the photosensitive layer is attached to an aromatic ring of a charge transporting compound [(tetrahydro-2H-pyran. 2-yl) oxy] methyl group, a compound having three or more groups, which is polymerized by a reaction in which a part of the [(tetrahydro-2H-pyran-2-yl) oxy] methyl group is cut off and eliminated An index (C / D) / (A / B) representing the remaining amount of [(tetrahydro-2H-pyran-2-yl) oxy] methyl group in the three-dimensional cross-linked film is as follows: The electrophotographic photosensitive member is characterized by satisfying the above condition.
(C / D) / (A / B) = 0.35-0.60 (I)
However, in the condition (I), A to D are as follows.
A = Infrared absorption spectrum intensity of aliphatic C—H stretching vibration peak (2940 ± 10 cm ⁻¹ ) of charge transporting compound before reaction B = Aromatic C—H stretching vibration peak of charge transporting compound before reaction ( 3028 ± 10 cm ⁻¹ ) Infrared absorption spectrum intensity C = 3D cross-linked aliphatic chain CH stretching vibration peak (2940 ± 10 cm ⁻¹ ) Infrared absorption spectrum intensity D = 3D cross-linked aromatic C Infrared absorption spectrum intensity of —H stretching vibration peak (3028 ± 10 cm ⁻¹ ) ”is disclosed.

Patent Document 2 includes “a conductive substrate and a photosensitive layer provided on the surface of the conductive substrate, and the outermost surface layer of the photosensitive layer is at least one selected from a guanamine compound and a melamine compound; Guanamine, comprising a cross-linked product using at least one charge transporting material having at least one substituent selected from OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. At least one selected from a compound and a melamine compound is contained in an amount of 0.1% by mass or more and 5% by mass or less, and the charge transporting material is contained in an amount of 90% by mass or more.
An electrophotographic photosensitive member characterized by the above. Is disclosed.

JP2012-150400A JP 2009-229549 A

  In the present invention, the outermost surface layer includes a charge transport compound in which either [(tetrahydro-2H-pyran-2-yl) oxy] methyl group or methylol group is linked to an aromatic ring of a charge transport skeleton, Compared to a cured film of a composition that does not include a charge transport compound in which an aromatic ring of a transport skeleton is linked to a [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and a methylol group, the outermost surface layer is An object of the present invention is to provide an electrophotographic photosensitive member that does not easily peel off.

In order to achieve the above object, the following invention is provided.
The invention according to claim 1
A conductive substrate;
A photosensitive layer disposed on the conductive substrate;
Have
A charge transport compound having a structure in which an outermost surface layer has a charge transport skeleton containing an aromatic ring, and a [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and a methylol group are linked to the aromatic ring. An electrophotographic photoreceptor which is a cured film of a composition containing A.

The invention according to claim 2
The electrophotographic photoreceptor according to claim 1, wherein the charge transport compound A is a compound represented by the following general formula (A).

(In general formula (A), F represents a charge transport skeleton containing an aromatic ring, and [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and methylol group are each represented by F.) (It is connected to the aromatic ring of the skeleton. M and n each independently represents an integer of 1 or more.)

The invention according to claim 3
The electrophotographic photoreceptor according to claim 1, wherein the charge transport compound A is a compound represented by the following general formula (A-1).

In general formula (A-1), Ar ^{1 to} Ar ⁴ may be the same or different and each independently represents a substituted or unsubstituted aryl group, and Ar ⁵ represents a substituted or unsubstituted aryl group or a substituted or unsubstituted aryl group. Represents an unsubstituted arylene group, X ^{1 to} X ⁵ represent a [(tetrahydro-2H-pyran-2-yl) oxy] methyl group, Y ^{1 to} Y ⁵ represent a methylol group, and m 1 to m ⁵ each independently And n1 to n5 each independently represents an integer of 0 or more and 1 or less, and p represents 0 or 1. However, the sum of m1 to m5 is 1 or more, and the sum of n1 to n5 is 1 or more.

The invention according to claim 4
The composition contains a charge transport compound S having a reactive group in addition to the charge transport compound A, and the content of the charge transport compound A with respect to 100 parts by mass of the charge transport compound S in the composition is The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the electrophotographic photoreceptor is 5 parts by mass or more.

The invention according to claim 5
The electrophotographic photosensitive member according to claim 4, wherein the content of the charge transport compound A with respect to 100 parts by mass of the charge transport compound S in the composition is 50 parts by mass or less.

The invention according to claim 6
The electrophotographic photosensitive member according to claim 4, wherein the charge transport compound S has three or more of the reactive groups in one molecule.

The invention according to claim 7 provides:
The electrophotographic photoreceptor according to any one of claims 1 to 6,
A process cartridge that can be attached to and detached from an image forming apparatus.

The invention according to claim 8 provides:
The electrophotographic photosensitive member according to any one of claims 1 to 6,
Charging means for charging the surface of the electrophotographic photosensitive member;
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image;
Transfer means for transferring the toner image to the surface of the recording medium;
An image forming apparatus comprising:

  According to the first, second, and third aspects of the invention, the outermost surface layer has one of [[tetrahydro-2H-pyran-2-yl) oxy] methyl group and methylol group on the aromatic ring of the charge transport skeleton. A cured film of a composition containing a charge transport compound in which [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and methylol group are linked to the aromatic ring of the charge transport skeleton As compared with the case of the above, an electrophotographic photosensitive member is provided in which the outermost surface layer is hardly peeled off.

  According to the invention of claim 4, the composition contains a charge transport compound S having a reactive group in addition to the charge transport compound A, and the content of the charge transport compound S in the composition is 100 parts by mass. As compared with the case where the content of the charge transport compound A is less than 5 parts by mass, an electrophotographic photosensitive member in which the outermost surface layer is hardly peeled is provided.

  According to the invention which concerns on Claim 5, compared with the case where content of the said charge transport compound A with respect to 100 mass parts of said charge transport compound S in the said composition exceeds 50 mass parts, an increase in residual potential and An electrophotographic photosensitive member in which wear is suppressed is provided.

  According to the sixth aspect of the present invention, there is provided an electrophotographic photosensitive member in which wear is suppressed as compared with the case where the charge transport compound S has two or less reactive groups.

  According to the inventions according to claims 7 and 8, the outermost surface layer is connected to the aromatic ring of the charge transport skeleton with any one of [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and methylol group. And a cured film of a composition that does not include a charge transport compound in which a [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and a methylol group are linked to an aromatic ring of a charge transport skeleton. A process cartridge and an image forming apparatus are provided in which the outermost surface layer of the electrophotographic photosensitive member is less likely to be peeled off than when the electrophotographic photosensitive member is provided.

1 is a schematic partial cross-sectional view illustrating an example of a layer configuration of an electrophotographic photoreceptor according to an exemplary embodiment. FIG. 6 is a schematic partial cross-sectional view illustrating another example of the layer configuration of the electrophotographic photosensitive member according to the exemplary embodiment. FIG. 6 is a schematic partial cross-sectional view illustrating another example of the layer configuration of the electrophotographic photosensitive member according to the exemplary embodiment. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows the image forming apparatus which concerns on other this embodiment. 4 is a graph showing an infrared absorption spectrum of exemplary compound AI-1 obtained in Synthesis Example 1. FIG.

  Embodiments that are examples of the present invention will be described below.

[Electrophotographic photoreceptor]
The electrophotographic photoreceptor according to the exemplary embodiment includes a conductive substrate and a photosensitive layer disposed on the conductive substrate, and the outermost surface layer has a charge transport skeleton including an aromatic ring, and It is a cured film of a composition comprising a charge transport compound A having a structure in which a [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and a methylol group are linked to the aromatic ring.

  In the electrophotographic photoreceptor according to the exemplary embodiment, as the charge transport material, the outermost surface layer includes an aromatic ring having a charge transport skeleton, [(tetrahydro-2H-pyran-2-yl) oxy] methyl group, and methylol group. A composition comprising any one of the charge transport compounds linked to each other, and no charge transport compound containing [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and methylol group linked to the aromatic ring of the charge transport skeleton. Compared with the case of the cured film, the outermost surface layer is difficult to peel off. Although the reason is not clear, the outermost surface layer of the electrophotographic photosensitive member has at least one [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and at least one methylol group in the aromatic ring. It is considered that the anchoring effect on the lower layer (for example, the charge transport layer) is improved and the adhesiveness is improved by being formed as a cured film of the composition containing.

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

  An electrophotographic photoreceptor 7A shown in FIG. 1 is a so-called function-separated photoreceptor (or laminated photoreceptor), and an undercoat layer 1 is provided on a conductive substrate 4, on which a charge generation layer 2 and a charge are formed. The transport layer 3 and the protective layer 5 have a structure formed sequentially. In the electrophotographic photoreceptor 7A, the charge generation layer 2 and the charge transport layer 3 constitute a photosensitive layer.

An electrophotographic photoreceptor 7B shown in FIG. 2 is a function-separated type photoreceptor in which the functions are separated into the charge generation layer 2 and the charge transport layer 3 like the electrophotographic photoreceptor 7A shown in FIG.
In the electrophotographic photoreceptor 7B shown in FIG. 2, a structure in which an undercoat layer 1 is provided on a conductive substrate 4, and a charge transport layer 3, a charge generation layer 2, and a protective layer 5 are sequentially formed thereon. It is what has. In the electrophotographic photoreceptor 7B, the charge transport layer 3 and the charge generation layer 2 constitute a photosensitive layer.

  The electrophotographic photoreceptor 7C shown in FIG. 3 contains a charge generation material and a charge transport material in the same layer (single layer type photosensitive layer 6). The electrophotographic photoreceptor 7C shown in FIG. 1 has a structure in which an undercoat layer 1 is provided on a conductive substrate 4, and a single-layer type photosensitive layer 6 and a protective layer 5 are sequentially formed thereon. .

  In the electrophotographic photoreceptors 7A, 7B, and 7C shown in FIGS. 1, 2, and 3, the protective layer 5 is the outermost surface layer disposed on the side farthest from the conductive substrate 4, The outermost surface layer has the above configuration.

  The electrophotographic photosensitive member in the present embodiment is not limited to the layer configuration shown in FIGS. 1 to 3. For example, the undercoat layer 1 may not be provided, or between the undercoat layer 1 and the photosensitive layer. An intermediate layer may be included.

  Hereinafter, each element of the electrophotographic photoreceptor 7A shown in FIG. 1 will be described as a representative example. In some cases, the reference numerals are omitted.

(Conductive substrate)
Examples of the conductive substrate include metal plates (eg, aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.), metal drums, metal belts, etc. Is mentioned. In addition, as the conductive substrate, for example, paper, resin film, belt, etc. coated, vapor-deposited or laminated with a conductive compound (for example, conductive polymer, indium oxide, etc.), metal (for example, aluminum, palladium, gold, etc.) or an alloy, etc. Also mentioned. Here, “conductive” means that the volume resistivity is less than 10 ¹³ Ωcm.

  When the electrophotographic photosensitive member is used in a laser printer, the surface of the conductive substrate has a center line average roughness Ra of 0.04 μm or more and 0.5 μm for the purpose of suppressing interference fringes generated when laser light is irradiated. The surface is preferably roughened below. When non-interfering light is used as a light source, roughening for preventing interference fringes is not particularly required, but it is suitable for extending the life because it suppresses generation of defects due to irregularities on the surface of the conductive substrate.

  As a roughening method, for example, wet honing performed by suspending an abrasive in water and spraying it on a support, centerless grinding in which a conductive substrate is pressed against a rotating grindstone, and grinding is continuously performed, Anodizing treatment etc. are mentioned.

  As a roughening method, without roughening the surface of the conductive substrate, conductive or semiconductive powder is dispersed in the resin to form a layer on the surface of the conductive substrate. The method of roughening by the particle | grains disperse | distributed in a layer is also mentioned.

  In the roughening treatment by anodic oxidation, a metal (for example, aluminum) conductive substrate is used as an anode, and an oxide film is formed on the surface of the conductive substrate by anodizing in an electrolyte solution. Examples of the electrolyte solution include a sulfuric acid solution and an oxalic acid solution. However, the porous anodic oxide film formed by anodic oxidation is chemically active as it is, easily contaminated, and has a large resistance fluctuation due to the environment. Therefore, the pores of the oxide film are blocked by the volume expansion due to the hydration reaction in pressurized water vapor or boiling water (a metal salt such as nickel may be added) against the porous anodic oxide film, and more stable hydration oxidation It is preferable to perform a sealing treatment for changing to a product.

  The thickness of the anodized film is preferably, for example, 0.3 μm or more and 15 μm or less. When this film thickness is within the above range, the barrier property against implantation tends to be exhibited, and the increase in residual potential due to repeated use tends to be suppressed.

The conductive substrate may be treated with an acidic treatment liquid or boehmite treatment.
The treatment with the acidic treatment liquid is performed as follows, for example. First, an acidic treatment liquid containing phosphoric acid, chromic acid and hydrofluoric acid is prepared. The mixing ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment liquid is, for example, in the range of 10% by mass to 11% by mass of phosphoric acid, in the range of 3% by mass to 5% by mass of chromic acid, The concentration of these acids is preferably in the range of 13.5% by mass or more and 18% by mass or less. The treatment temperature is preferably 42 ° C. or higher and 48 ° C. or lower, for example. The film thickness is preferably from 0.3 μm to 15 μm.

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

(Undercoat layer)
The undercoat layer is, for example, a layer containing inorganic particles and a binder resin.

Examples of the inorganic particles include inorganic particles having a powder resistance (volume resistivity) of 10 ² Ωcm or more and 10 ¹¹ Ωcm or less.
Among these, as the inorganic particles having the resistance value, for example, metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles are preferable, and zinc oxide particles are particularly preferable.

The specific surface area of the inorganic particles by the BET method is preferably 10 m ² / g or more, for example.
The volume average particle diameter of the inorganic particles is, for example, preferably from 50 nm to 2000 nm (preferably from 60 nm to 1000 nm).

  For example, the content of the inorganic particles is preferably 10% by mass or more and 80% by mass or less, and more preferably 40% by mass or more and 80% by mass or less with respect to the binder resin.

  The inorganic particles may be subjected to a surface treatment. Two or more inorganic particles having different surface treatments or particles having different particle diameters may be mixed and used.

  Examples of the surface treatment agent include a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, and a surfactant. In particular, a silane coupling agent is preferable, and an amino group-containing silane coupling agent is more preferable.

  Examples of the silane coupling agent having an amino group include 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and N-2- (aminoethyl) -3-amino. Examples include, but are not limited to, propylmethyldimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, and the like.

  Two or more silane coupling agents may be used in combination. For example, a silane coupling agent having an amino group and another silane coupling agent may be used in combination. Other silane coupling agents include, for example, vinyltrimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycol. Sidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- ( Aminoethyl) -3-aminopropylmethyldimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, and the like, but are not limited thereto. It is not a thing.

  The surface treatment method using the surface treatment agent may be any method as long as it is a known method, and may be either a dry method or a wet method.

  The treatment amount of the surface treatment agent is preferably 0.5% by mass or more and 10% by mass or less with respect to the inorganic particles, for example.

  Here, the undercoat layer may contain an electron-accepting compound (acceptor compound) together with the inorganic particles from the viewpoint of enhancing the long-term stability of the electric characteristics and the carrier blocking property.

Examples of the electron accepting compound include quinone compounds such as chloranil and bromoanil; tetracyanoquinodimethane compounds; 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone, and the like. 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4- Oxadiazole compounds such as oxadiazole and 2,5-bis (4-diethylaminophenyl) -1,3,4 oxadiazole; xanthone compounds; thiophene compounds; 3,3 ′, 5,5 ′ tetra- electron transporting substances such as diphenoquinone compounds such as t-butyldiphenoquinone;
In particular, the electron-accepting compound is preferably a compound having an anthraquinone structure. As the compound having an anthraquinone structure, for example, a hydroxyanthraquinone compound, an aminoanthraquinone compound, an aminohydroxyanthraquinone compound, and the like are preferable, and specifically, for example, anthraquinone, alizarin, quinizarin, anthralfin, and purpurin are preferable.

  The electron-accepting compound may be dispersed and included in the undercoat layer together with the inorganic particles, or may be included in a state of being attached to the surface of the inorganic particles.

  Examples of the method for attaching the electron accepting compound to the surface of the inorganic particles include a dry method and a wet method.

  In the dry method, for example, while stirring inorganic particles with a mixer having a large shearing force or the like, an electron-accepting compound dissolved directly or in an organic solvent is dropped and sprayed with dry air or nitrogen gas. It is a method of adhering to the surface of inorganic particles. When the electron-accepting compound is dropped or sprayed, it is preferably performed at a temperature not higher than the boiling point of the solvent. After dropping or spraying the electron-accepting compound, baking may be performed at 100 ° C. or higher. The baking is not particularly limited as long as it is a temperature and time for obtaining electrophotographic characteristics.

  In the wet method, for example, an electron-accepting compound is added while dispersing inorganic particles in a solvent by stirring, ultrasonic waves, a sand mill, an attritor, a ball mill, etc., and after stirring or dispersing, the solvent is removed to remove electrons. This is a method of attaching a receptive compound to the surface of inorganic particles. The solvent removal method is distilled off by filtration or distillation, for example. After removing the solvent, baking may be performed at 100 ° C. or higher. The baking is not particularly limited as long as it is a temperature and time for obtaining electrophotographic characteristics. In the wet method, the water content of the inorganic particles may be removed before adding the electron-accepting compound. Examples thereof include a method of removing while stirring and heating in a solvent, and a method of removing by azeotropic distillation with a solvent. Can be mentioned.

  The attachment of the electron-accepting compound may be performed before or after the surface treatment with the surface treatment agent is performed on the inorganic particles, or may be performed simultaneously with the attachment of the electron-accepting compound and the surface treatment with the surface treatment agent.

  The content of the electron-accepting compound is, for example, from 0.01% by mass to 20% by mass with respect to the inorganic particles, and preferably from 0.01% by mass to 10% by mass.

Examples of the binder resin used for the undercoat layer include acetal resins (eg, polyvinyl butyral), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, and unsaturated polyesters. Resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, urea resin, phenol resin, phenol-formaldehyde resin, melamine resin, Known polymer compounds such as urethane resin, alkyd resin, epoxy resin; zirconium chelate compound; titanium chelate compound; aluminum chelate compound; titanium alkoxide compound ; Organic titanium compounds; known materials silane coupling agent, and the like.
Examples of the binder resin used for the undercoat layer include a charge transport resin having a charge transport group, a conductive resin (for example, polyaniline) and the like.

Among these, as the binder resin used for the undercoat layer, a resin insoluble in the upper coating solvent is preferable, and in particular, a urea resin, a phenol resin, a phenol-formaldehyde resin, a melamine resin, a urethane resin, and an unsaturated polyester. Thermosetting resins such as resins, alkyd resins, and epoxy resins; at least one resin selected from the group consisting of polyamide resins, polyester resins, polyether resins, methacrylic resins, acrylic resins, polyvinyl alcohol resins, and polyvinyl acetal resins; Resins obtained by reaction with curing agents are preferred.
When these binder resins are used in combination of two or more, the mixing ratio is set as necessary.

The undercoat layer may contain various additives for improving electrical characteristics, improving environmental stability, and improving image quality.
Additives include known materials such as electron transport pigments such as polycyclic condensation systems and azo systems, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, and silane coupling agents. It is done. The silane coupling agent is used for the surface treatment of the inorganic particles as described above, but may be further added to the undercoat layer as an additive.

  Examples of the silane coupling agent as the additive include vinyltrimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3- Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (Aminoethyl) -3-aminopropylmethylmethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane and the like can be mentioned.

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

The undercoat layer preferably has a Vickers hardness of 35 or more.
The surface roughness (ten-point average roughness) of the undercoat layer is adjusted from 1 / 4n (n is the refractive index of the upper layer) to 1 / 2λ of the exposure laser wavelength λ used to suppress moire images. It should be done.
Resin particles or the like may be added to the undercoat layer for adjusting the surface roughness. Examples of the resin particles include silicone resin particles and cross-linked polymethyl methacrylate resin particles. Further, the surface of the undercoat layer may be polished for adjusting the surface roughness. Examples of the polishing method include buffing, sandblasting, wet honing, and grinding.

  There is no particular limitation on the formation of the undercoat layer, and a well-known formation method is used. For example, a coating film for forming an undercoat layer in which the above components are added to a solvent is formed, and the coating film is dried. And heating as necessary.

Solvents for preparing the coating solution for forming the undercoat layer include known organic solvents such as alcohol solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone solvents, ketone alcohol solvents, ether solvents. Examples include solvents and ester solvents.
Specific examples of these solvents include methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, Examples include ordinary organic solvents such as n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene.

  Examples of the dispersion method of the inorganic particles when preparing the coating liquid for forming the undercoat layer include known methods such as a roll mill, a ball mill, a vibration ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker.

  Examples of the method for applying the coating liquid for forming the undercoat layer onto the conductive substrate include, for example, 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. The usual methods, such as these, are mentioned.

  The thickness of the undercoat layer is, for example, preferably set in the range of 15 μm or more, more preferably 20 μm or more and 50 μm or less.

(Middle layer)
Although illustration is omitted, an intermediate layer may be further provided between the undercoat layer and the photosensitive layer.
An intermediate | middle layer is a layer containing resin, for example. Examples of the resin used for the intermediate layer include an acetal resin (for example, polyvinyl butyral), polyvinyl alcohol resin, polyvinyl acetal resin, casein resin, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, Polymer compounds such as polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin, and the like can be given.
The intermediate layer may be a layer containing an organometallic compound. Examples of the organometallic compound used for the intermediate layer include organometallic compounds containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon.
The compounds used for these intermediate layers may be used alone or as a mixture or polycondensate of a plurality of compounds.

  Among these, the intermediate layer is preferably a layer containing an organometallic compound containing a zirconium atom or a silicon atom.

The formation of the intermediate layer is not particularly limited, and a well-known formation method is used. For example, a coating film of an intermediate layer forming coating solution in which the above components are added to a solvent is formed, and the coating film is dried and necessary. It is performed by heating according to.
As the coating method for forming the intermediate layer, usual methods such as a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, and a curtain coating method are used.

  For example, the thickness of the intermediate layer is preferably set in a range of 0.1 μm to 3 μm. An intermediate layer may be used as the undercoat layer.

(Charge generation layer)
The charge generation layer is, for example, a layer containing a charge generation material and a binder resin. The charge generation layer may be a vapor deposition layer of a charge generation material. The vapor-deposited layer of the charge generation material is suitable when an incoherent light source such as an LED (Light Emitting Diode) or an organic EL (Electro-Luminescence) image array is used.

  Examples of the charge generation material include azo pigments such as bisazo and trisazo; fused aromatic pigments such as dibromoanthanthrone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide;

  Among these, in order to cope with near-infrared laser exposure, it is preferable to use a metal phthalocyanine pigment or a metal-free phthalocyanine pigment as the charge generation material. Specifically, for example, hydroxygallium phthalocyanine disclosed in JP-A-5-263007, JP-A-5-279591, etc .; chlorogallium phthalocyanine disclosed in JP-A-5-98181; More preferred are dichlorotin phthalocyanines disclosed in JP-A No. 140472, JP-A No. 5-140473 and the like; and titanyl phthalocyanine disclosed in JP-A No. 4-189873.

  On the other hand, in order to cope with laser exposure in the near-ultraviolet region, as the charge generation material, condensed aromatic pigments such as dibromoanthanthrone; thioindigo pigments; porphyrazine compounds; zinc oxide; trigonal selenium; Bisazo pigments and the like disclosed in 2004-78147 and JP-A-2005-181992 are preferred.

  The above-described charge generation material may also be used in the case of using an incoherent light source such as an LED having a central wavelength of light emission of 450 nm to 780 nm and an organic EL image array. However, from the viewpoint of resolution, the photosensitive layer is 20 μm or less. When the thin film is used, the electric field strength in the photosensitive layer is increased, and a charge decrease due to charge injection from the substrate, that is, an image defect called a black spot is likely to occur. This becomes conspicuous when a charge generating material that easily generates a dark current is used in a p-type semiconductor such as trigonal selenium or a phthalocyanine pigment.

On the other hand, when an n-type semiconductor such as a condensed ring aromatic pigment, perylene pigment, azo pigment or the like is used as the charge generation material, dark current hardly occurs and even a thin film can suppress image defects called black spots. . Examples of the n-type charge generation material include compounds (CG-1) to (CG-27) described in paragraphs [0288] to [0291] of JP2012-155282A. It is not limited.
The n-type determination is performed by using a time-of-flight method that is usually used, and is determined by the polarity of the flowing photocurrent, and an n-type is more likely to flow electrons as carriers than holes.

The binder resin used for the charge generation layer is selected from a wide range of insulating resins, and the binder resin is selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinyl anthracene, polyvinyl pyrene, and polysilane. You may choose.
As the binder resin, for example, polyvinyl butyral resin, polyarylate resin (polycondensate of bisphenol and aromatic divalent carboxylic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, Examples thereof include polyamide resin, acrylic resin, polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, and the like. Here, “insulating” means that the volume resistivity is 10 ¹³ Ωcm or more.
These binder resins are used singly or in combination of two or more.

  The mixing ratio of the charge generation material and the binder resin is preferably in the range of 10: 1 to 1:10 by mass ratio.

  In addition, the charge generation layer may contain a known additive.

  The formation of the charge generation layer is not particularly limited, and a known formation method is used. For example, a coating film of a charge generation layer forming coating solution in which the above components are added to a solvent is formed, and the coating film is dried. And heating as necessary. The charge generation layer may be formed by vapor deposition of a charge generation material. Formation of the charge generation layer by vapor deposition is particularly suitable when a condensed ring aromatic pigment or perylene pigment is used as the charge generation material.

  Solvents for preparing the charge generation layer forming coating solution include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-acetate. -Butyl, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, toluene and the like. These solvents are used alone or in combination of two or more.

Examples of a method for dispersing particles (for example, a charge generation material) in a coating solution for forming a charge generation layer include, for example, a media disperser such as a ball mill, a vibrating ball mill, an attritor, a sand mill, a horizontal sand mill, a stirring, an ultrasonic disperser, etc. Medialess dispersers such as roll mills and high-pressure homogenizers are used. Examples of the high-pressure homogenizer include a collision method in which a dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high pressure state, and a penetration method in which a fine flow path is dispersed in a high pressure state.
In this dispersion, it is effective that the average particle size of the charge generation material in the coating solution for forming the charge generation layer is 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less. .

  Examples of methods for applying the charge generation layer forming coating solution on the undercoat layer (or on the intermediate layer) include blade coating, wire bar coating, spray coating, dip coating, bead coating, and air knife coating. And usual methods such as a curtain coating method.

  The film thickness of the charge generation layer is, for example, preferably set in the range of 0.1 μm to 5.0 μm, more preferably 0.2 μm to 2.0 μm.

(Charge transport layer)
The charge transport layer is, for example, a layer containing a charge transport material and a binder resin. The charge transport layer may be a layer containing a polymer charge transport material.

  Examples of charge transport materials include quinone compounds such as p-benzoquinone, chloranil, bromanyl and anthraquinone; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone; xanthone compounds; benzophenone compounds A cyanovinyl compound; an electron transporting compound such as an ethylene compound; Examples of the charge transporting material include hole transporting compounds such as triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, and hydrazone compounds. These charge transport materials may be used alone or in combination of two or more, but are not limited thereto.

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

In Structural Formula (a-1), Ar ^T1 , Ar ^T2 , and Ar ^T3 are each independently a substituted or unsubstituted aryl group, —C ₆ H ₄ —C (R ^T4 ) ═C (R ^T5 ) (R ^T6), or _{-C 6 H 4 -CH = CH-} CH = C (R T7) shows the ^{(R T8).} R ^T4 , R ^T5 , R ^T6 , R ^T7 , and R ^T8 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.
Examples of the substituent for each group include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. Examples of the substituent of each group also include a substituted amino group substituted with an alkyl group having 1 to 3 carbon atoms.

In Structural Formula (a-2), R ^T91 and R ^T92 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. R ^T101 , R ^T102 , R ^T111 and R ^T112 are each independently ^substituted with a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 1 to 2 carbon atoms. A substituted amino group, a substituted or unsubstituted aryl group, —C (R ^T12 ) ═C (R ^T13 ) (R ^T14 ), or —CH═CH— ^CH═C (R ^T15 ) (R ^T16 ), R ^T12 , R ^T13 , R ^T14 , R ^T15 and R ^T16 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Tm1, Tm2, Tn1, and Tn2 each independently represent an integer of 0 or more and 2 or less.
Examples of the substituent for each group include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. Examples of the substituent of each group also include a substituted amino group substituted with an alkyl group having 1 to 3 carbon atoms.

Here, among the triarylamine derivative represented by the structural formula (a-1) and the benzidine derivative represented by the structural formula (a-2), in particular, “—C ₆ H ₄ —CH═CH—CH═ Triarylamine derivatives having “C (R ^T7 ) (R ^T8 )” and benzidine derivatives having “—CH═CH— ^CH═C (R ^T15 ) (R ^T16 )” are preferable from the viewpoint of charge mobility.

  As the polymer charge transporting material, known materials having charge transporting properties such as poly-N-vinylcarbazole and polysilane are used. In particular, polyester-based polymer charge transport materials disclosed in JP-A-8-176293, JP-A-8-208820 and the like are particularly preferable. The polymer charge transport material may be used alone or in combination with a binder resin.

The binder resin used for the charge transport layer is polycarbonate resin, polyester resin, polyarylate resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, Vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N -Vinylcarbazole, polysilane, etc. are mentioned. Among these, as the binder resin, a polycarbonate resin or a polyarylate resin is preferable. These binder resins are used alone or in combination of two or more.
The mixing ratio of the charge transport material and the binder resin is preferably 10: 1 to 1: 5 by mass ratio.

  In addition, the charge transport layer may contain a known additive.

  The formation of the charge transport layer is not particularly limited, and a known formation method is used. For example, a coating film of a charge transport layer forming coating solution in which the above components are added to a solvent is formed, and the coating film is dried. This is done by heating as necessary.

  Solvents for preparing the coating solution for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene; ketones such as acetone and 2-butanone; methylene chloride, chloroform and ethylene chloride. Halogenated aliphatic hydrocarbons: Usual organic solvents such as cyclic or linear ethers such as tetrahydrofuran and ethyl ether. These solvents are used alone or in combination of two or more.

  Coating methods for applying the charge transport layer forming coating solution on the charge generation layer include blade coating method, wire bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain A usual method such as a coating method may be mentioned.

  The thickness of the charge transport layer is, for example, preferably set in the range of 5 μm to 50 μm, more preferably 10 μm to 30 μm.

(Protective layer)
The protective layer is the outermost surface layer in the electrophotographic photosensitive member, and is a layer separately provided to protect the photosensitive layer composed of the charge generation layer 2 and the charge transport layer 3. By having the protective layer 5, the outermost surface of the photoreceptor can be resistant to abrasion, scratches, and the like, and toner transfer efficiency can be improved. The protective layer in this embodiment has a charge transport skeleton containing an aromatic ring, and a structure in which a [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and a methylol group are linked to the aromatic ring. It is the cured film of the composition containing the charge transport compound A which has this.

-Charge transport compound A-
The charge transport compound A has a charge transport skeleton including an aromatic ring, and has a structure in which a [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and a methylol group are linked to the aromatic ring. That is, the charge transport compound A has a structure in which at least one [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and at least one methylol group are linked to the aromatic ring of the charge transport skeleton.
Here, the “charge transport skeleton containing an aromatic ring” means an organic group containing an aromatic ring derived from a compound having a charge transport ability.

The aromatic ring contained in the charge transport skeleton may be monocyclic, polycyclic or condensed. For example, substituted or unsubstituted benzene (monocyclic aromatic hydrocarbon); polycyclic aromatic hydrocarbons in which a plurality of benzenes such as biphenyl and triphenyl are single-bonded; naphthalene, phenalene, phenanthrene, anthracene, triphenylene, pyrene, Condensed ring aromatic hydrocarbons such as chrysene and tetracene; a compound in which two or more selected from benzene, the polycyclic aromatic hydrocarbon and the condensed ring aromatic hydrocarbon are single-bonded; a plurality of benzenes having 1 to 12 carbon atoms The following alkyl groups (for example, straight chain such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, etc.) A compound bonded through a branched alkyl group; benzene, the polycyclic aromatic hydrocarbon, and the condensed ring aroma 2 or more selected from hydrocarbons are alkyl groups having 1 to 12 carbon atoms (for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert- Compounds having a single bond via a straight-chain or branched alkyl group such as a butyl group, a pentyl group, or a hexyl group;
Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, a hydroxy group, and a halogen atom (for example, fluorine, chlorine, bromine, iodine).
Examples of the substituent include alkyl groups having 1 to 6 carbon atoms (for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, A linear or branched alkyl group such as a pentyl group or a hexyl group) or a hydroxy group is desirable, and a methyl group or a hydroxy group is more desirable.

  In the charge transport compound A, the [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and the methylol group may be linked to the same aromatic ring included in the charge transport skeleton, or [(tetrahydro A structure in which a methylol group is linked to a ring other than the ring to which the -2H-pyran-2-yl) oxy] methyl group is linked may be used.

  The charge transport compound A is preferably a compound represented by the following general formula (A).

  In the general formula (A), F represents a charge transport skeleton containing an aromatic ring, and the [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and the methylol group are each represented by F. It is connected to the aromatic ring. m and n each independently represents an integer of 1 or more. From the viewpoint of film strength and electrical characteristics, preferably, m is 1 or more and 3 or less, and n is 1 or more and 3 or less.

  In addition, the [(tetrahydro-2H-pyran-2-yl) oxy] methyl group contained in the charge transport compound A is represented by the following formula (X), the methylol group is represented by the following formula (Y), and * is the charge transport skeleton. A binding site with an aromatic ring contained in F is represented.

  The charge transport compound A represented by the general formula (A) is more preferably a compound represented by the following general formula (A-1).

In general formula (A-1), Ar ^{1 to} Ar ⁴ may be the same or different and each independently represents a substituted or unsubstituted aryl group, and Ar ⁵ represents a substituted or unsubstituted aryl group or a substituted or unsubstituted aryl group. Represents an unsubstituted arylene group, X ^{1 to} X ⁵ represent a [(tetrahydro-2H-pyran-2-yl) oxy] methyl group, Y ^{1 to} Y ⁵ represent a methylol group, and m 1 to m ⁵ each independently And n1 to n5 each independently represents an integer of 0 or more and 1 or less, and p represents 0 or 1. However, the sum of m1 to m5 is 1 or more, and the sum of n1 to n5 is 1 or more.
From the viewpoint of film strength and electrical characteristics, the total of m1 to m5 is preferably 1 or more and 3 or less, and the total of n1 to n5 is 1 or more and 3 or less.

  Specific examples of the charge transport compound A are shown below, but the charge transport compound A used in the present embodiment is not limited to the following examples.

  The charge transport compound A used in the present embodiment can be produced, for example, by the following method.

[Synthesis example]
Hereinafter, specific synthesis examples will be described, but the method for synthesizing the charge transport compound A used in the present embodiment is not limited to the following method.

[Synthesis Example 1]
Synthesis of Exemplary Compound (AI-1) 3.05 g of 4,4 ′-(phenylimino) bis (4,1-phenylene) dimethanol and 0.84 g of 3,4-dihydro-2H-pyran were dissolved in 40 ml of tetrahydrofuran. And kept below 10 ° C. in an ice bath.
To this, 10 mg of paratoluenesulfonic acid was added and allowed to react for 2 hours while maintaining 20 ° C. or lower. After the reaction, 100 ml of ethyl acetate was added and washed with water. The organic layer was dried over sodium sulfate, separated and purified by silica gel chromatography (developing solvent: toluene / ethyl acetate = 2/1), and the exemplified compound (AI-1). 0.41 g was obtained.
FIG. 6 shows an infrared absorption spectrum (KBr tablet method) of the compound obtained in Synthesis Example 1.

-Reactive charge transport compound S-
The composition forming the cured film constituting the protective layer preferably contains a charge transport compound other than the charge transport compound A from the viewpoint of charge transport properties of the protective layer, and has a charge transport compound having a reactive group (reactive property). More preferably, it comprises a charge transport compound S).

  The reactive charge transport compound S having a reactive group other than the charge transport compound A contains two or more reactive groups in one molecule from the viewpoints of wear resistance, image quality characteristics, electrical characteristics and the like of the electrophotographic photoreceptor. It is preferable that three or more are included.

The reactive charge transport compound S includes —OH, —OR ¹⁰ (R ¹⁰ represents an alkyl group having 1 to 12 carbon atoms), —NH ₂ , —SH, —COOH, and carbon The charge transport compound may be at least one kind having at least one substituent selected from a group having a functional group having a heavy bond. In particular, the reactive charge transport compound S includes at least two substituents selected from —OH, —OR ¹⁰ , —NH ₂ , —SH, —COOH, and a group having a functional group having a carbon double bond. One (or three) charge transport compound is desirable. When the reactive functional group (substituent) increases in the charge transport compound, the crosslink density increases and a cured film with higher strength is easily obtained.

The reactive charge transport compound S is preferably a compound represented by the following general formula (C).
Fr- (D) _n3 ... General formula (C)
In general formula (C), Fr represents an organic group (charge transport skeleton) derived from a compound having a charge transporting ability, and D represents — (— R ¹¹ —Z) _n1 (R ¹² ) _n2 —Y (provided that , R ¹¹ and R ¹² each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms, Z represents an oxygen, NH or sulfur atom, Y represents —OH, —OR ¹⁰ ( R ¹⁰ represents an alkyl group having 1 to 12 carbon atoms), —NH ₂ , —SH or —COOH, n 1 represents 0 or 1, n 2 represents 0 or 1, and carbon double A group having a functional group having a bond is represented, and n3 represents an integer of 1 or more and 4 or less.

  Examples of the group having a functional group having a carbon double bond represented by D include acryloyl group, methacryloyl group, styryl group (vinylphenyl group), allyl group, vinyl group, vinyl ether group, allyl vinyl ether group, and the like. And a group having at least one selected from the derivatives. In particular, a group having a group selected from these at the terminal is desirable.

  In general formula (C), an arylamine derivative is preferably exemplified as the compound having charge transporting ability in the “organic group derived from the compound having charge transporting ability” represented by Fr. Preferred examples of the arylamine derivative include a triphenylamine derivative and a tetraphenylbenzidine derivative.

  The compound represented by the general formula (C) is preferably a compound represented by the following general formula (C-1).

In general formula (C-1), Ar ^C1 , Ar ^C2 , Ar ^C3 and Ar ^C4 each independently represent a substituted or unsubstituted aryl group, and may be the same or different.
Ar ^C5 represents a substituted or unsubstituted aryl group or a substituted or unsubstituted arylene group.

D represents — (— R ¹¹ —Z) _n1 (R ¹² ) _n2 —Y (wherein R ¹¹ and R ¹² each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms; Z represents an oxygen, NH, or sulfur atom, Y represents —OH, —OR ¹⁰ (R ¹⁰ represents an alkyl group having 1 to 12 carbon atoms), —NH ₂ , —SH, or —COOH, n 1 Represents 0 or 1, and n2 represents 0 or 1.), or — (CH ₂ ) _d — (O—CH ₂ —CH ₂ ) _f —O—CO—C (R ′) ═CH ₂ (provided that , R ′ represents a hydrogen atom or a methyl group, d represents an integer of 1 to 5, and f represents 0 or 1. e represents 0 or 1 independently at each position, and the total number of D is 1 or more and 4 or less. k represents 0 or 1;

Regarding Ar ^{C1 to} Ar ^C5 , the substituent in the substituted aryl group and the substituted arylene group is a group other than D, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, substituted or unsubstituted And an aryl group having 6 to 10 carbon atoms.

In the general formula (C-1), when D is “— (— R ¹¹ —Z) _n1 (R ¹² ) _n2 —Y”, R ¹¹ and R ¹² are each independently a straight chain having 1 to 5 carbon atoms. A branched or branched alkylene group, n1 is preferably 1, n2 is preferably 1, and Z is preferably oxygen.

  In the general formula (C-1), the total number of D corresponds to n3 in the general formula (C), preferably 2 or more and 4 or less, and more preferably 3 or more and 4 or less. When the total number of D is 2 or more and 4 or less, preferably 3 or more and 4 or less in one molecule, the crosslinking density is increased and a cured film having higher strength can be obtained.

In general formula (C-1), Ar ^C1 , Ar ^C2 , Ar ^C3 and Ar ^C4 are preferably any of the following formulas (1) to (7). The following formulas (1) to (7) are shown together with “— (D) _e ” which can be linked to each of Ar ^C1 , Ar ^C2 , Ar ^C3 and Ar ^C4 .

In the formulas (1) to (7), R ¹³ is phenyl substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Represents one selected from the group consisting of a group, an unsubstituted phenyl group, and an aralkyl group having 7 to 10 carbon atoms, wherein R ¹⁴ , R ¹⁵ and R ¹⁶ are each independently a hydrogen atom, 1 to 4 carbon atoms An alkyl group having 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom. 1 represents one selected from the group, Ar represents a substituted or unsubstituted arylene group, D and e are the same as “D” and “e” in formula (C-1), and s is 0 or 1 T is 1 It represents the upper 3 an integer.

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

In formula (8) or (9), R ¹⁷ and R ¹⁸ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. This represents one type selected from the group consisting of a substituted phenyl group, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, and t represents an integer of 1 to 3.

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

In formulas (10) to (17), R ¹⁹ and R ²⁰ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. It represents one selected from the group consisting of a substituted phenyl group, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, W represents a divalent group, and q and r are respectively Represents an integer of 1 to 10, and t represents an integer of 1 to 3.

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

In the general formula (C-1), Ar ^C5 is an aryl group of the above formulas (1) to (7) exemplified in the description of Ar ^{C1 to} Ar ^C4 when k is 0, and when k is 1 Is an arylene group obtained by removing a hydrogen atom from the aryl groups of the above formulas (1) to (7).

  Specific examples of the compound represented by the general formula (C) include compounds i-1 to i-25, compounds ii-1 to ii-56, and iii-1 to iii described in JP2011-175038A. -19, iv-1 to iv-49, v-1 to v-3, vi-1 to vi-6, compound I-1 to compound I-31 described in JP2011-112801A, and JP Compound I-1 thru | or Compound I-34 as described in 2011-27808 gazette are mentioned.

  The composition for forming a protective layer in the present embodiment includes, as the reactive charge transport compound S, the reactive charge transport compound S having an alkoxy group from the viewpoints of wear resistance, image quality characteristics, electrical characteristics, and the like of the electrophotographic photoreceptor. It is desirable to include at least one reactive charge transport compound S having a hydroxyl group.

  The addition amount of the reactive charge transport compound S with respect to the total solid content of the outermost surface layer (protective layer 5) is preferably 60% by mass to 95% by mass, and more preferably 60% by mass to 90% by mass. Is more desirable, and 65 mass% or more and 90 mass% or less is especially desirable.

  Here, specific examples of the reactive charge transport compound S having a hydroxyl group and the reactive charge transport compound S having an alkoxy group among the compounds represented by the general formula (C-1) are given. However, it is not limited to the following.

  When the composition for forming the protective layer contains the charge transport compound S having a reactive group in addition to the charge transport compound A, the charge in the composition for forming the protective layer is used from the viewpoint of improving the adhesion to the charge transport layer. The content of the charge transport compound A relative to 100 parts by mass of the transport compound S is preferably 3 parts by mass or more, and more preferably 5 parts by mass or more.

  On the other hand, from the viewpoint of suppressing increase in residual potential and wear, the content of the charge transport compound A with respect to 100 parts by mass of the charge transport compound S in the protective layer forming composition is preferably 60 parts by mass or less. More preferably, it is 50 parts by mass or less. It is considered that the transfer of charges becomes smooth due to the improved adhesion between the protective layer and the charge transport layer, and the residual potential can be kept low.

  Further, from the viewpoint of improving adhesiveness with the charge transport layer and suppressing residual potential, the content of the charge transport compound A with respect to 100 parts by weight of the charge transport compound S in the protective layer forming composition is 10 parts by weight. More preferably, it is 20 parts by mass or less.

In the present embodiment, the protective layer forming composition may contain one or more charge transport compounds A, and may contain one or more charge transport compounds S.
When one or both of the charge transport compound A and the charge transport compound S includes a plurality of types of charge transport compounds, the ratio of the total amount of each charge transport compound is preferably in the above range.

  The total amount of the charge transport compound in the protective layer forming composition is preferably 60% by mass or more and 95% by mass or less, and 75% by mass or more and 95% by mass or less, based on the total amount of the solid. Is more preferable.

(Guanamine compounds, melamine compounds)
The composition for forming the protective layer includes a compound having a guanamine structure (hereinafter also referred to as “guanamine compound”) and a melamine structure in order to further improve the abrasion resistance and electrical stability of the electrophotographic photoreceptor. At least one selected from compounds having the following (hereinafter also referred to as “melamine compound”) may be included.

-Guanamine compounds-
A guanamine compound is a compound having a guanamine skeleton (structure), and examples thereof include acetoguanamine, benzoguanamine, formoguanamine, steroguanamine, spiroguanamine, and cyclohexylguanamine.

  The guanamine compound is particularly preferably at least one of a compound represented by the following general formula (H) and a multimer thereof. Here, the multimer is an oligomer polymerized using the compound represented by the general formula (H) as a structural unit, and the degree of polymerization thereof is, for example, 2 or more and 200 or less (desirably 2 or more and 100 or less). The compound represented by the general formula (H) or a multimer thereof may be used alone or in combination of two or more. When the compound represented by the general formula (H) is used as a mixture of two or more kinds or used as a multimer (oligomer) having the structural unit as a structural unit, the solubility in a solvent is improved.

In General Formula (H), R ^H1 represents a linear or branched alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, or a substituted or unsubstituted carbon. This represents an alicyclic hydrocarbon group of several 4 or more and 10 or less. R ^{H2 to} R ^H5 each independently represents a hydrogen atom, —CH ₂ —OH, or —CH ₂ —O—R ^H6 . R ^H6 represents a linear or branched alkyl group having 1 to 10 carbon atoms.

When R ^H1 is a linear or branched alkyl group having 1 to 10 carbon atoms, the carbon number is preferably 1 to 8 and more preferably 1 to 5 carbon atoms.
When R ^H1 is a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, it preferably has 6 to 8 carbon atoms. Examples of the substituent when the phenyl group is substituted include a methyl group, an ethyl group, and a propyl group.

When R ^H1 is a substituted or unsubstituted alicyclic hydrocarbon group having 4 to 10 carbon atoms, it preferably has 5 to 8 carbon atoms. Examples of the substituent when the alicyclic hydrocarbon group is substituted include a methyl group, an ethyl group, and a propyl group.
The linear or branched alkyl group having 1 to 10 carbon atoms represented by R ^H6 desirably has 1 to 8 carbon atoms, more desirably 1 to 6 carbon atoms (for example, methyl Group, ethyl group, butyl group, etc.).

In the compound represented by the general formula (H), it is particularly desirable that R ^H1 is a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, and R ^{H2 to} R ^H5 are each independently —CH ₂ —O—. a compound represented by R ^{H6, R H6} is methyl or n- butyl.
The compound represented by the general formula (H) is synthesized by, for example, a known method (for example, “Experimental Chemistry Course”, 4th edition, Volume 28, page 430) using guanamine and formaldehyde.

  Although the specific example of a compound represented by general formula (H) below is shown, it is not necessarily restricted to these. Moreover, although the following specific examples show a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient.

  Examples of commercially available compounds represented by the general formula (H) include superbecamine (R) L-148-55, superbecamine (R) 13-535, and superbecamine (R) L-145. 60, Superbecamine (R) TD-126 (manufactured by DIC Corporation), Nicarak BL-60, Nicarac BX-4000 (manufactured by Nippon Carbide Corporation), and the like.

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

-Melamine compounds-
The melamine compound is a compound having a melamine skeleton (structure), and is particularly preferably at least one of a compound represented by the following general formula (J) and a multimer thereof. Here, the multimer is an oligomer polymerized using the compound represented by the general formula (J) as a structural unit, and the degree of polymerization thereof is, for example, 2 or more and 200 or less (desirably 2 or more and 100 or less). The compound represented by the general formula (J) or a multimer thereof may be used alone or in combination of two or more. When the compound represented by the general formula (J) is used as a mixture of two or more kinds or used as a multimer (oligomer) having the same as a structural unit, the solubility in a solvent is improved.

In General Formula (J), R ^{J6 to} R ^J11 each independently represent a hydrogen atom, —CH ₂ —OH, —CH ₂ —O—R ^J12 , or —O—R ^J12 , and R ^J12 represents the number of carbon atoms. 1 or more and 5 or less linear or branched alkyl group is represented. Examples of the alkyl group include a methyl group, an ethyl group, and a butyl group.

The compound represented by the general formula (J) is synthesized by a known method (for example, “Experimental Chemistry Course”, 4th edition, Volume 28, page 430) using, for example, melamine and formaldehyde.
Although the specific example of a compound represented by general formula (J) below is shown, it is not necessarily restricted to these. Moreover, although the following specific examples show a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient.

  As a commercial item of the compound represented by the general formula (J), for example, Super Melami No. 90 (manufactured by NOF Corporation), Super Becamine (R) TD-139-60 (manufactured by DIC), Uban 2020 (manufactured by Mitsui Chemicals), Smitex Resin M-3 (manufactured by Sumitomo Chemical Co., Ltd.), Nicarac MW -30 (made by Nippon Carbide).

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

  When using at least one selected from a guanamine compound and a melamine compound, it is desirable to use as the reactive charge transport compound S at least one selected from reactive charge transport compounds S having an alkoxy group, It is more desirable to use at least one selected from reactive charge transport compounds S having a hydroxyl group.

In this case, the total addition amount of the guanamine compound and the melamine compound is 0.1% by mass with respect to the total solid content of the outermost surface layer (protective layer) excluding the fluororesin particles and the fluorinated alkyl group-containing copolymer. The content is preferably 25% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, and further preferably 1% by mass or more and 20% by mass or less.
By setting the protective layer to the above configuration, the protective layer becomes a denser cured film, and the wear resistance and electrical characteristics of the electrophotographic photosensitive member are further improved.

  The total content of the charge transport compound A, the total content of the reactive charge transport compound S, the total content of the guanamine compound and the melamine compound, etc. in the protective layer are determined by the composition of these compounds in the composition for forming the protective layer. Controlled by adjusting solids concentration.

  In addition to the charge transport compound, a phenol resin, urea resin, alkyd resin, or the like may be used in combination for the protective layer. In order to improve the strength, a compound having a larger number of functional groups in one molecule such as spiroacetal guanamine resin (for example, “CTU-guanamine” manufactured by Ajinomoto Fine Techno Co., Ltd.) It is also effective to copolymerize the material.

  The protective layer may be mixed with other thermosetting resins such as phenol resin for the purpose of effectively suppressing oxidation by the discharge generated gas so that the discharge generated gas is not excessively adsorbed.

An antioxidant may be added to the protective layer. The antioxidant is an additive used for the purpose of suppressing deterioration due to an oxidizing gas such as ozone generated in the charging device.
Examples of antioxidants include hindered phenol antioxidants, aromatic amine antioxidants, hindered amine antioxidants, organic sulfur antioxidants, phosphite antioxidants, and dithiocarbamate antioxidants. And known antioxidants such as oxidants, thiourea antioxidants, and benzimidazole antioxidants.

  A surfactant is preferably added to the protective layer. The surfactant is not particularly limited as long as it is a surfactant containing at least one of a fluorine atom, an alkylene oxide structure, and a silicone structure. It is preferable because it has high affinity and compatibility, improves the film-forming property of the coating liquid for forming the protective layer, and suppresses wrinkles and unevenness of the protective layer.

  For the purpose of suppressing wear of the protective layer, the protective layer-forming coating solution may contain fluorine-containing resin particles, and in order to maintain the dispersion stability of the fluorine-containing resin particles, a fluorinated alkyl group-containing copolymer May be blended.

  The protective layer may be used by mixing with a coupling agent or a fluorine compound for the purpose of adjusting film formability, flexibility, lubricity, and adhesion. As this compound, various silane coupling agents and commercially available silicone hard coat agents are used.

The protective layer is made of alcohol for the purposes of discharge gas resistance, mechanical strength, scratch resistance, particle dispersibility, viscosity control, torque reduction, wear amount control, pot life (storability of coating liquid for layer formation), etc. A dissolving resin may be added.
Here, the resin that dissolves in alcohol means a resin that dissolves 1% by mass or more in an alcohol having 5 or less carbon atoms. As resin which melt | dissolves in alcohol, polyvinyl acetal resin and polyvinyl phenol resin are mentioned, for example.

Various particles may be added to the protective layer for the purpose of lowering the residual potential or improving the strength. An example of the particles is silicon-containing particles. The silicon-containing particles are particles containing silicon as a constituent element, and specific examples include colloidal silica and silicone particles.
Further, an oil such as silicone oil may be added to the protective layer.

  Metals, metal oxides, carbon black and the like may be added to the protective layer.

The protective layer is charge transport compound A. A cured film (cross-linked film) obtained by polymerizing (cross-linking) the reactive charge transport compound S, and a guanamine compound and a melamine compound used as necessary using an acid catalyst is desirable.
Acid catalysts include aliphatic carboxylic acids such as acetic acid, chloroacetic acid, trichloroacetic acid, trifluoroacetic acid, oxalic acid, maleic acid, malonic acid, and lactic acid; aromatics such as benzoic acid, phthalic acid, terephthalic acid, and trimellitic acid Carboxylic acids: Aliphatic or aromatic sulfonic acids such as methanesulfonic acid, dodecylsulfonic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, etc. are used, but sulfur-containing materials (especially organic sulfonic acids) And derivatives thereof).

  Here, the compounding amount of the catalyst is desirably in the range of 0.01% by mass or more and 0.1% by mass or less, particularly 0.05% by mass or more and 0.0. 1 mass% or less is desirable. When the amount is less than the above range, the catalytic activity may be too low, and when it exceeds the above range, the light resistance may be deteriorated. The light resistance refers to a phenomenon in which the irradiated portion causes a decrease in density when the photosensitive layer is exposed to light from the outside such as room light. The cause is not clear, but it is presumed that a phenomenon similar to the optical memory effect occurs as disclosed in JP-A-5-099737.

  The protective layer having the above structure is formed using a protective layer-forming coating solution in which the above components are mixed. The coating liquid for forming the protective layer may be prepared without a solvent, or may be performed using a solvent as necessary. Such solvents are used singly or in combination of two or more, and preferably have a boiling point of 100 ° C. or lower. As the solvent, it is particularly preferable to use a solvent having at least one hydroxyl group (for example, alcohol).

  In addition, when a coating solution is obtained by reacting the above components, it may be simply mixed and dissolved, but it is room temperature (for example, 25 ° C.) to 100 ° C., preferably 30 ° C. to 80 ° C., for 10 minutes to 100 Heating may be performed for a period of time, preferably 1 hour to 50 hours. It is also desirable to irradiate ultrasonic waves at this time. Thereby, it is likely that a partial reaction proceeds, and it becomes easy to obtain a film with few coating film defects and little variation in thickness.

  Then, the coating liquid for forming the protective layer is applied by a known method such as blade coating method, Mayer bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating method, etc. Accordingly, for example, the protective layer is obtained by heating and curing at a temperature of 100 ° C. or higher and 170 ° C. or lower.

  The film thickness of the protective layer is desirably 1 μm or more and 15 μm or less, and more desirably 3 μm or more and 10 μm or less.

-Method for forming protective layer-
The protective layer 5 is prepared by preparing a coating solution for forming a protective layer containing the above-described components in a solvent, coating the coating solution to form a coating film, and heating the coating film to at least charge transport Compound A is subjected to condensation polymerization to form a polymer and dried to remove the solvent, and then formed.

  Examples of the solvent used in the protective layer-forming coating solution include cyclic aliphatic ketone compounds such as cyclobutanone, cyclopentanone, cyclohexanone, and cycloheptanone; cyclic such as methanol, ethanol, propanol, butanol, and cyclopentanol; Linear alcohols; linear ketones such as acetone and methyl ethyl ketone; cyclic or linear ethers such as tetrahydrofuran, dioxane, ethylene glycol, diethyl ether, and sillopentyl methyl ether; methylene chloride, chloroform, ethylene chloride, and the like And halogenated aliphatic hydrocarbon solvents. A solvent may be used individually by 1 type, or may mix and use 2 or more types.

  In the heating step, for example, when the charge transport compound having a reactive group is condensed and polymerized by heating at a temperature of 100 ° C. to 170 ° C. for 30 minutes to 60 minutes, and the guanamine compound or melamine compound described above is further added If so, the polymer is formed by the progress of the cross-linking polymerization, and the solvent is removed to form a cured film, whereby the protective layer 5 is obtained.

(Single layer type photosensitive layer)
The single-layer type photosensitive layer (charge generation / charge transport layer) is, for example, a layer containing a charge generation material, a charge transport material, and, if necessary, a binder resin and other known additives. Note that these materials are the same as those described for the charge generation layer and the charge transport layer.
In the single-layer type photosensitive layer, the content of the charge generating material is preferably 10% by mass or more and 85% by mass or less, and preferably 20% by mass or more and 50% by mass or less with respect to the total solid content. In the single-layer type photosensitive layer, the content of the charge transport material is preferably 5% by mass or more and 50% by mass or less based on the total solid content.
The method for forming the single-layer type photosensitive layer is the same as the method for forming the charge generation layer and the charge transport layer.
The film thickness of the single-layer type photosensitive layer is, for example, from 5 μm to 50 μm, and preferably from 10 μm to 40 μm.

  As shown in FIG. 3, when the protective layer 5 is formed as the outermost surface layer on the single-layer type photosensitive layer 6, the same configuration as that of the protective layer described above provided on the charge transport layer may be used.

[Image forming apparatus (and process cartridge)]
The image forming apparatus according to the present embodiment includes an electrophotographic photosensitive member, a charging unit that charges the surface of the electrophotographic photosensitive member, and an electrostatic latent image formation that forms an electrostatic latent image on the surface of the charged electrophotographic photosensitive member. Means, developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image, and transfer means for transferring the toner image to the surface of the recording medium; Is provided. The electrophotographic photosensitive member according to the present embodiment is applied as the electrophotographic photosensitive member.

  The image forming apparatus according to the present embodiment includes an apparatus having fixing means for fixing a toner image transferred to the surface of a recording medium; direct transfer for directly transferring the toner image formed on the surface of the electrophotographic photosensitive member to the recording medium Type apparatus; intermediate transfer in which the toner image formed on the surface of the electrophotographic photosensitive member is primarily transferred onto the surface of the intermediate transfer member, and the toner image transferred onto the surface of the intermediate transfer member is secondarily transferred onto the surface of the recording medium. Type of apparatus; apparatus with cleaning means for cleaning the surface of the electrophotographic photosensitive member after the toner image is transferred and before charging; after the toner image is transferred, the surface of the electrophotographic photosensitive member is irradiated with a charge eliminating light before charging. A known image forming apparatus such as an apparatus provided with an electrophotographic photoreceptor heating member for raising the temperature of the electrophotographic photoreceptor and reducing the relative temperature is applied.

  In the case of an intermediate transfer type apparatus, the transfer means includes, for example, an intermediate transfer body on which a toner image is transferred to the surface, and a primary transfer that primarily transfers the toner image formed on the surface of the electrophotographic photosensitive member to the surface of the intermediate transfer body. A configuration including a transfer unit and a secondary transfer unit that secondarily transfers the toner image transferred onto the surface of the intermediate transfer member onto the surface of the recording medium is applied.

  The image forming apparatus according to the present embodiment may be either a dry developing type image forming apparatus or a wet developing type (developing type using a liquid developer).

  Note that in the image forming apparatus according to the present embodiment, for example, the portion including the electrophotographic photosensitive member may have a cartridge structure (process cartridge) that is detachable from the image forming apparatus. As the process cartridge, for example, a process cartridge including the electrophotographic photosensitive member according to this embodiment is preferably used. In addition to the electrophotographic photosensitive member, the process cartridge may include at least one selected from the group consisting of a charging unit, an electrostatic latent image forming unit, a developing unit, and a transfer unit.

  Hereinafter, an example of the image forming apparatus according to the present embodiment will be described, but the present invention is not limited thereto. In addition, the main part shown to a figure is demonstrated and the description is abbreviate | omitted about others.

FIG. 4 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present embodiment.
As shown in FIG. 4, the image forming apparatus 100 according to this embodiment includes a process cartridge 300 including an electrophotographic photosensitive member 7, an exposure device 9 (an example of an electrostatic latent image forming unit), and a transfer device 40 (primary. Transfer device) and an intermediate transfer member 50. In the image forming apparatus 100, the exposure device 9 is disposed at a position where the electrophotographic photosensitive member 7 can be exposed from the opening of the process cartridge 300, and the transfer device 40 is interposed between the electrophotographic photosensitive member via the intermediate transfer member 50. 7, and a part of the intermediate transfer member 50 is disposed in contact with the electrophotographic photosensitive member 7. Although not shown, it also has a secondary transfer device that transfers the toner image transferred to the intermediate transfer member 50 to a recording medium (for example, paper). The intermediate transfer member 50, the transfer device 40 (primary transfer device), and the secondary transfer device (not shown) correspond to an example of a transfer unit.

  In the process cartridge 300 in FIG. 4, an electrophotographic photosensitive member 7, a charging device 8 (an example of a charging unit), a developing device 11 (an example of a developing unit), and a cleaning device 13 (an example of a cleaning unit) are integrated in a housing. I support it. The cleaning device 13 includes a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is disposed so as to contact the surface of the electrophotographic photosensitive member 7. The cleaning member may be a conductive or insulating fibrous member instead of the cleaning blade 131, and may be used alone or in combination with the cleaning blade 131.

  In FIG. 4, as an image forming apparatus, a fibrous member 132 (roll shape) for supplying the lubricant 14 to the surface of the electrophotographic photosensitive member 7 and a fibrous member 133 (flat brush shape) for assisting cleaning are shown. Examples are provided, but these are arranged as necessary.

  Hereinafter, each configuration of the image forming apparatus according to the present embodiment will be described.

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

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

-Developer-
Examples of the developing device 11 include a general developing device that performs development by bringing a developer into contact or non-contact with the developer. The developing device 11 is not particularly limited as long as it has the functions described above, and is selected according to the purpose. For example, a known developing device having a function of attaching a one-component developer or a two-component developer to the electrophotographic photosensitive member 7 using a brush, a roller, or the like can be used. Among these, those using a developing roller holding the developer on the surface are preferable.

  The developer used in the developing device 11 may be a one-component developer including a toner alone or a two-component developer including a toner and a carrier. Further, the developer may be magnetic or non-magnetic. A well-known thing is applied for these developers.

-Cleaning device-
As the cleaning device 13, a cleaning blade type device including a cleaning blade 131 is used.
In addition to the cleaning blade method, a fur brush cleaning method and a simultaneous development cleaning method may be employed.

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

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

FIG. 5 is a schematic configuration diagram illustrating another example of the image forming apparatus according to the present embodiment.
An image forming apparatus 120 shown in FIG. 5 is a tandem multicolor image forming apparatus equipped with four process cartridges 300. In the image forming apparatus 120, four process cartridges 300 are arranged in parallel on the intermediate transfer member 50, and one electrophotographic photosensitive member is used for one color. The image forming apparatus 120 has the same configuration as that of the image forming apparatus 100 except that it is a tandem system.

  Note that the image forming apparatus 100 according to the present embodiment is not limited to the above configuration, and is, for example, a cleaning device around the electrophotographic photosensitive member 7 and downstream of the transfer device 40 in the rotation direction of the electrophotographic photosensitive member 7. The first toner neutralizing device may be provided on the upstream side of the rotation direction of the electrophotographic photosensitive member with respect to 13 so that the polarity of the remaining toner is aligned and easily removed with a cleaning brush. Alternatively, a configuration may be adopted in which a second static elimination device for neutralizing the surface of the electrophotographic photosensitive member 7 is provided on the downstream side in the rotation direction of the electrophotographic photosensitive member and on the upstream side in the rotational direction of the electrophotographic photosensitive member relative to the charging device 8. .

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all. Unless otherwise specified, “parts” in the following Examples and Comparative Examples means “parts by mass” and “%” means “% by mass”.

[Example 1]
(Formation of undercoat layer)
100 parts of zinc oxide (average particle diameter 70 nm: manufactured by Teika: specific surface area value 15 m ² / g) is stirred and mixed with 500 parts of tetrahydrofuran, and 1.2 parts of a silane coupling agent (KBM502: manufactured by Shin-Etsu Chemical Co., Ltd.) is added. And stirred for 2 hours. Tetrahydrofuran was then distilled off under reduced pressure and baked at 120 ° C. for 3 hours to obtain a silane coupling agent surface-treated zinc oxide.

  110 parts of the surface-treated zinc oxide was stirred and mixed with 500 parts of tetrahydrofuran, a solution prepared by dissolving 0.7 parts of alizarin in 50 parts of tetrahydrofuran was added, and the mixture was stirred at 50 ° C. for 4 hours. Then, the zinc oxide to which alizarin was imparted by filtration under reduced pressure was filtered off, and further dried at 60 ° C. under reduced pressure to obtain alizarin imparted zinc oxide.

  60 parts of this alizarin-provided zinc oxide, 13.5 parts of a curing agent (blocked isocyanate, Sumidur 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.), 15 parts of butyral resin (ESREC BM-1, manufactured by Sekisui Chemical Co., Ltd.), A solution obtained by dissolving 38 parts of methyl ethyl ketone in 85 parts of methyl ethyl ketone and 30 parts of methyl ethyl ketone were mixed and dispersed in a sand mill for 2 hours 30 minutes using 1 mmφ glass beads to obtain a dispersion.

  As a catalyst, 0.005 part of dioctyltin dilaurate and 40 parts of silicone resin particles (Tospearl 145, manufactured by Momentive Performance Materials) were added to the resulting dispersion to obtain a coating liquid for forming an undercoat layer. This coating solution was applied on an aluminum substrate having a diameter of 84 mm, a length of 357 mm, and a thickness of 1 mm by a dip coating method, followed by drying and curing at 170 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 21 μm.

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

(Formation of charge transport layer)
33 parts of N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1 ′] biphenyl-4,4′-diamine, 10 parts of the following compound (HT-**), and 57 parts of bisphenol Z polycarbonate resin (viscosity average molecular weight: 50,000) was added to 800 parts of chlorobenzene and dissolved to obtain a coating solution for forming a charge transport layer. This coating solution was applied onto the charge generation layer and dried at 135 ° C. for 45 minutes to form a charge transport layer having a thickness of 21 μm.

(Formation of protective layer)
The following composition was mixed to prepare a coating solution for forming a protective layer.

-Composition for forming a protective layer-
・ Guanamine resin Nicalak BL-60 (manufactured by Nippon Carbide): 5 parts ・ Charge transport compound represented by the following compound S-1: 85 parts ・ Charge transport compound represented by the following exemplified compound AI-1: 8.5 Parts · antioxidant 3,5-di-t-butyl-4-hydroxytoluene (BHT): 1.5 parts · NACURE2107 (manufactured by King Industries): 0.075 parts · leveling agent (surfactant BYK-302 , Manufactured by Big Chemie Japan Co., Ltd.)
: 0.05 part · Cyclopentanol (solvent): 100 parts · Sillopentyl methyl ether (solvent): 50 parts

This coating solution is applied onto the charge transport layer by a dip coating method, air-dried at room temperature (25 ° C.) for 20 minutes, and then heated and cured at 145 ° C. for 40 minutes to form a protective layer having a thickness of 6.8 μm. Thus, a photoreceptor was produced.
Further, a photosensitive layer for adhesion evaluation was produced by forming a protective layer having a thickness of 2.0 μm.

[Examples 2 to 9]
In the formation of the protective layer in Example 1, Example 2 thru | or Example 2 thru | or was carried out similarly to Example 1 except having changed exemplary compound AI-1 into the charge transport compound or content shown in Table 1, and having formed the protective layer. 9 photoreceptors were prepared. In addition, when changing the composition ratio of the charge transport material, the total content of the charge transport material was not changed, and the addition ratio of the compound S-1 and the other charge transport compound was adjusted.
In Examples 2 to 9, the structure of the charge transport compound used instead of the exemplified compound AI-1 is shown below.

[Comparative Examples 1 to 4]
In the formation of the protective layer in Example 1, Comparative Example 1 to Comparative Example 1 were carried out in the same manner as in Example 1 except that the protective layer was formed by changing Exemplified Compound AI-1 to the charge transport compound or content shown in Table 1. No. 4 photoconductor was produced.
The structures of Compound B, Compound C and Compound D are shown below.

[Evaluation]
<Abrasion amount>
The photoconductor produced as described above is mounted at a black position of Color 1000 press manufactured by Fuji Xerox Co., Ltd., and continuously printed 1000 sheets of A4 size print pattern with an image density of 5% in an environment of 10 ° C. and 15% RH per minute. The amount of wear on the surface of the photoreceptor after printing 100 sheets, a total of 100,000 sheets, was measured.

  The wear amount is measured in advance by measuring the initial film thickness of the outermost surface layer, measuring the difference between the initial film thickness and the film thickness after printing a total of 100,000 sheets, and the wear amount of the protective layer (μm ) Was calculated. In addition, although the film thickness was measured using the self-made interference type film thickness measuring device, you may use a commercially available film thickness measuring device (for example, a permscope by Fisherscope, etc.) if the amount of wear is calculated.

<Adhesiveness>
A cross-cut tape peeling test was performed on the photoreceptor for evaluation of adhesiveness (protective layer thickness of 2 μm) prepared as described above in accordance with JIS D0202-1988. Using cellophane tape (“CT24”, manufactured by Nichiban Co., Ltd.), the film was adhered to the film with the finger pad and then peeled off. Judgment is represented by the number of squares that do not peel out of 100 squares. The case where the protective layer does not peel from the charge transport layer is 0%, and the case where the protective layer is completely peeled is 100%.
A: 0% or more and less than 10% B: 10% or more and less than 40% C: 40% or more and less than 80% D: 80% or more

<Light part potential>
The photoconductor produced as described above was mounted on a Color 1000 press remodeling machine (process speed increase) manufactured by Fuji Xerox Co., Ltd., and the light portion potential was measured under the following conditions.
Room temperature 10 ℃ Humidity 15%
It is charged to dark part potential 700V, exposure amount is 1.5mJ / m ² , 41ms after exposure. Black solid image quality is printed at this time. confirmed.

  Table 1 shows the charge transport compounds other than Compound S-1 and the evaluation results in the outermost surface layer of the electrophotographic photosensitive member produced in Examples and Comparative Examples.

DESCRIPTION OF SYMBOLS 1 Undercoat layer, 2 Charge generation layer, 3 Charge transport layer, 4 Conductive substrate, 5 Protective layer, 6 Single layer type photosensitive layer, 7A, 7B, 7C, 7 Electrophotographic photoreceptor, 8 Charging device, 9 Exposure device , 11 Developing device, 13 Cleaning device, 14 Lubricant, 40 Transfer device, 50 Intermediate transfer member, 100 Image forming device, 120 Image forming device, 131 Cleaning blade, 132 Fibrous member, 133 Fibrous member, 300 Process cartridge

Claims (8)

A conductive substrate;
A photosensitive layer disposed on the conductive substrate;
Have
A charge transport compound having a structure in which an outermost surface layer has a charge transport skeleton containing an aromatic ring, and a [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and a methylol group are linked to the aromatic ring. An electrophotographic photoreceptor which is a cured film of a composition containing A. The electrophotographic photoreceptor according to claim 1, wherein the charge transport compound A is a compound represented by the following general formula (A).

(In general formula (A), F represents a charge transport skeleton containing an aromatic ring, and [(tetrahydro-2H-pyran-2-yl) oxy] methyl group and methylol group are each represented by F.) (It is connected to the aromatic ring of the skeleton. M and n each independently represents an integer of 1 or more.) The electrophotographic photoreceptor according to claim 1, wherein the charge transport compound A is a compound represented by the following general formula (A-1).

(In General Formula (A-1), Ar ^{1 to} Ar ⁴ may be the same or different and each independently represents a substituted or unsubstituted aryl group, and Ar ⁵ represents a substituted or unsubstituted aryl group or a substituted group. Or an unsubstituted arylene group, X ^{1 to} X ⁵ each represent a [(tetrahydro-2H-pyran-2-yl) oxy] methyl group, Y ^{1 to} Y ⁵ each represent a methylol group, and m 1 to m ⁵ each represent Each independently represents an integer from 0 to 1, n1 to n5 each independently represents an integer from 0 to 1, and p represents 0 or 1. However, the sum of m1 to m5 is 1 or more, (The total of n1 to n5 is 1 or more.)   The composition contains a charge transport compound S having a reactive group in addition to the charge transport compound A, and the content of the charge transport compound A with respect to 100 parts by mass of the charge transport compound S in the composition is The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the electrophotographic photoreceptor is 5 parts by mass or more.   The electrophotographic photosensitive member according to claim 4, wherein the content of the charge transport compound A with respect to 100 parts by mass of the charge transport compound S in the composition is 50 parts by mass or less.   The electrophotographic photosensitive member according to claim 4, wherein the charge transport compound S has three or more of the reactive groups in one molecule. The electrophotographic photoreceptor according to any one of claims 1 to 6,
A process cartridge that can be attached to and detached from an image forming apparatus. The electrophotographic photosensitive member according to any one of claims 1 to 6,
Charging means for charging the surface of the electrophotographic photosensitive member;
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image;
Transfer means for transferring the toner image to the surface of the recording medium;
An image forming apparatus comprising: