JP2017049522A - Laminated electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated electrophotographic photoreceptor that can achieve both wear resistance and oil crack resistance.SOLUTION: There is provided a laminated electrophotographic photoreceptor comprising a photosensitive layer, where the photosensitive layer includes a charge generating layer containing a charge generating agent and a charge transport layer containing an electron transport agent, a binder resin, and silica particles. The charge transport layer is a single layer, and is arranged as an outermost surface layer. The electron transport agent includes a specific compound, and the average primary particle diameter of the silica particles is 50 nm or more and 150 nm or less. The content of the silica particles is 0.5 pts.mass or more and 15 pts.mass or less based on 100 pts.mass of the binder resin.SELECTED DRAWING: None

Description

  The present invention relates to a multilayer electrophotographic photosensitive member.

  An electrophotographic photosensitive member may be used as an image carrier in an electrophotographic image forming apparatus (for example, a printer or a multifunction peripheral). The electrophotographic photoreceptor includes a photosensitive layer. As the electrophotographic photosensitive member, for example, a multilayer electrophotographic photosensitive member is used. In the multilayer electrophotographic photoreceptor, the photosensitive layer includes a charge generation layer having a charge generation function and a charge transport layer having a charge transport function.

  The electrophotographic photoreceptor described in Patent Document 1 contains a modified polycarbonate resin and silica particles in the surface layer of the photoreceptor. The modified polycarbonate resin includes a repeating unit having a siloxane structure. The volume average particle diameter of the silica particles is 0.005 μm or more and less than 0.05 μm.

JP 2001-66800 A

  However, the electrophotographic photosensitive member described in Patent Document 1 has difficulty in achieving both wear resistance and oil crack resistance.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a multilayer electrophotographic photosensitive member capable of achieving both wear resistance and oil crack resistance.

  The laminated electrophotographic photoreceptor of the present invention includes a photosensitive layer. The photosensitive layer includes a charge generation layer containing a charge generation agent, and a charge transport layer containing an electron transport agent, a binder resin, and silica particles. The charge transport layer is a single layer. The charge transport layer is disposed as an outermost layer. The charge transport agent includes a compound represented by the general formula (1), (2) or (3). The average primary particle size of the silica particles is 50 nm or more and 150 nm or less. Content of the said silica particle is 0.5 to 15 mass parts with respect to 100 mass parts of said binder resins.

In the general formula (1), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ are each independently a hydrogen atom or an alkoxy group having 1 to 8 carbon atoms. , A phenyl group, or an alkyl group having 1 to 8 carbon atoms which may be substituted.

In the general formula (2), R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ , and R ₁₈ are each independently a hydrogen atom or an alkoxy having 1 to 8 carbon atoms. A group, a phenyl group, or an alkyl group having 1 to 8 carbon atoms which may be substituted;

In the general formula (3), R ₂₁ and R ₂₂ each independently represent a hydrogen atom, an alkoxy group, a phenyl group, or an optionally substituted alkyl group having 1 to 8 carbon atoms.

  According to the present invention, it is possible to provide a multi-layer electrophotographic photosensitive member capable of achieving both wear resistance and oil crack resistance.

(A) And (b) is sectional drawing which respectively shows the structure of the laminated electrophotographic photoreceptor which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention. In addition, although description may be abbreviate | omitted suitably about the location where description overlaps, the summary of invention is not limited.

  Hereinafter, an alkyl group having 1 to 8 carbon atoms, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, 1 carbon atom The alkoxy group having 6 to 6 carbon atoms, the cycloalkane having 5 to 7 carbon atoms, and the aryl group having 6 to 14 carbon atoms each have the following meanings.

  The alkyl group having 1 to 8 carbon atoms is a linear or branched alkyl group having 1 to 8 carbon atoms that is unsubstituted. Examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, pentyl group, isopentyl group, and neopentyl group. Hexyl group, heptyl group, or octyl group.

  The alkyl group having 1 to 6 carbon atoms is a linear or branched alkyl group having 1 to 6 carbon atoms that is unsubstituted. Examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, pentyl group, isopentyl group, and neopentyl group. Or a hexyl group.

  The alkyl group having 1 to 4 carbon atoms is a linear or branched alkyl group having 1 to 4 carbon atoms that is unsubstituted. Examples of the alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, and t-butyl group.

  The alkoxy group having 1 to 8 carbon atoms is a linear or branched alkoxy group having 1 to 8 carbon atoms which is unsubstituted. Examples of the alkoxy group having 1 to 8 carbon atoms include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, s-butoxy, t-butoxy, pentyloxy, iso Examples include a pentyloxy group, a neopentyloxy group, a hexyloxy group, a heptyloxy group, and an octyloxy group.

  The alkoxy group having 1 to 6 carbon atoms is a linear or branched alkoxy group having 1 to 6 carbon atoms which is unsubstituted. Examples of the alkoxy group having 1 to 6 carbon atoms include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, s-butoxy, t-butoxy, pentyloxy, iso Examples thereof include a pentyloxy group, a neopentyloxy group, and a hexyloxy group.

  The cycloalkane having 5 to 7 carbon atoms is, for example, an unsubstituted cycloalkane having 5 to 7 carbon atoms. Examples of the cycloalkane having 5 to 7 carbon atoms include cyclopentane, cyclohexane, and cycloheptane.

  Examples of the aryl group having 6 to 14 carbon atoms include an unsubstituted aromatic monocyclic hydrocarbon group having 6 to 14 carbon atoms and an unsubstituted aromatic condensed bicyclic carbon group having 6 to 14 carbon atoms. A hydrogen group or an unsubstituted aromatic condensed tricyclic hydrocarbon group having 6 to 14 elemental atoms; Examples of the aryl group having 6 to 14 carbon atoms include a phenyl group, a naphthyl group, an anthryl group, and a phenanthryl group.

<Photoconductor>
The multilayer electrophotographic photosensitive member of the present embodiment (hereinafter sometimes referred to as a photosensitive member) includes a photosensitive layer. Hereinafter, the structure of the photoreceptor according to the present embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view showing the structure of the photoreceptor 10. As shown in FIG. 1A, the photoreceptor 10 includes, for example, a conductive substrate 11 and a photosensitive layer 12. The photosensitive layer 12 includes a charge generation layer 13 (lower layer) and a charge transport layer 14 (upper layer). In the photosensitive layer 12, a charge generation layer 13 having a charge generation function and a charge transport layer 14 having a charge transport function are laminated. As shown in FIG. 1A, the charge transport layer 14 is disposed as the outermost surface layer of the photoreceptor 10. The charge transport layer 14 is a single layer (single layer).

  In addition, it can be confirmed using a transmission electron microscope (TEM) ("JSM-6700F" manufactured by JEOL Ltd.) that the charge transport layer is a single layer. Specifically, the cross section of the photosensitive layer is formed. An image of the cross section of the photosensitive layer is taken using a TEM. The obtained image is observed to confirm that the charge transport layer is a single layer.

  As shown in FIG. 1A, the photosensitive layer 12 may be disposed directly on the conductive substrate 11. As shown in FIG. 1B, the photoreceptor 10 includes, for example, a conductive substrate 11, an intermediate layer 15 (undercoat layer), and a photosensitive layer 12. As shown in FIG. 1B, the photosensitive layer 12 may be indirectly disposed on the conductive substrate 11. As shown in FIG. 1B, the intermediate layer 15 may be provided between the conductive substrate 11 and the charge generation layer 13. In this case, the photosensitive layer 12 is indirectly provided on the conductive substrate 11 via the intermediate layer 15. For example, the intermediate layer 15 may be provided between the charge generation layer 13 and the charge transport layer 14.

  In the photoreceptor 10 according to this embodiment, the charge generation layer 13 and the charge transport layer 14 are laminated in this order on the conductive substrate 11. The charge transport layer 14 is a single layer (single layer) and contains predetermined components described later. Such a charge transport layer 14 is disposed as the outermost surface layer of the photoreceptor 10. For this reason, it is easy to form the charge generation layer 13 thin. Specifically, since the charge transport layer 14 is disposed as the outermost surface layer of the photoreceptor 10, wear or loss of the charge generation layer 13 can be suppressed. In addition, the life of the charge generation layer 13 can be extended. The charge generation layer 13 may be formed thinner than the charge transport layer 14. The charge generation layer 13 may be a single layer or a plurality of layers.

  Further, when the charge transport layer 14 is disposed as the outermost surface layer of the photoconductor 10, image flow hardly occurs in the photoconductor 10 having such a configuration. Furthermore, such a photoreceptor 10 is easy to manufacture at low cost.

  The structure of the photoreceptor 10 according to the present embodiment has been described above with reference to FIG. Subsequently, the elements (conductive substrate 11, photosensitive layer 12, and intermediate layer 15) of the photoreceptor according to the present embodiment will be described. A method for manufacturing the photoreceptor is also described.

[1. Conductive substrate]
The conductive substrate is not particularly limited as long as it can be used as the conductive substrate of the photoreceptor. As the conductive substrate, for example, a conductive substrate formed of a material having at least a surface portion having conductivity can be used. As the conductive substrate, for example, a conductive substrate composed entirely of a conductive material, or a conductive substrate partially composed of a conductive material (more specifically, coated with a conductive material) Conductive substrate). For example, a conductive substrate in which a surface of an insulating material (for example, a plastic material or glass) is coated (for example, vapor deposition) with a conductive material may be used. Examples of the conductive material include aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, and brass. Among these materials having conductivity, one kind may be used alone, or two or more kinds may be used in combination (for example, as an alloy).

  Among these materials having conductivity, the transfer of electric charge from the photosensitive layer to the conductive substrate is good, and it is easy to form a more suitable image. Therefore, as the material having conductivity, aluminum or an aluminum alloy is used. preferable.

  The shape of the conductive substrate is not particularly limited. For example, it can be appropriately selected according to the structure of the image forming apparatus to which the photosensitive member is applied. For example, a sheet-like conductive substrate or a drum-shaped conductive substrate can be used. Further, the thickness of the conductive substrate can be appropriately selected according to the shape of the conductive substrate. However, in use, it is desirable that the conductive substrate has sufficient mechanical strength.

[2. Photosensitive layer]
As already described, the photosensitive layer includes a charge generation layer and a charge transport layer. The photosensitive layer may further contain an additive. Hereinafter, the charge generation layer and the charge transport layer will be described. Furthermore, an additive is demonstrated.

[2-1. Charge generation layer]
The charge generation layer contains, for example, a charge generation agent and a charge generation layer binder resin (hereinafter, sometimes referred to as a base resin). The thickness of the charge generation layer is not particularly limited as long as it can sufficiently function as the charge generation layer. Specifically, the thickness of the charge generation layer is preferably 0.01 μm or more and 5 μm or less, and more preferably 0.1 μm or more and 3 μm or less. Hereinafter, the charge generating agent and the base resin will be described.

[2-1-1. Charge generator]
The charge generator is not particularly limited as long as it is a charge generator for a photoreceptor. Examples of the charge generator include phthalocyanine pigments, perylene pigments, bisazo pigments, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, trisazo pigments, indigo pigments, azurenium pigments, cyanine pigments, Powder of inorganic photoconductive material such as selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, amorphous silicon, pyrylium salt, ansanthrone pigment, triphenylmethane pigment, selenium pigment, toluidine pigment, pyrazoline pigment Or quinacridone pigments.

Examples of the phthalocyanine pigment include a metal-free phthalocyanine pigment (more specifically, an X-type metal-free phthalocyanine (x-H ₂ Pc)) or a phthalocyanine derivative (more specifically, a metal phthalocyanine pigment). Examples of the metal phthalocyanine pigment include titanyl phthalocyanine (more specifically, Y-type titanyl phthalocyanine (Y-TiOPc) or V-type hydroxygallium phthalocyanine). The crystal shape of the phthalocyanine pigment is not particularly limited, and phthalocyanine pigments having various crystal shapes are used. Examples of the crystal shape of the phthalocyanine pigment include α-type, β-type, and Y-type. A charge generating agent may be used individually by 1 type, and may be used in combination of 2 or more type.

A charge generating agent having an absorption wavelength in a desired region may be used alone, or a photoreceptor having sensitivity in a desired wavelength region may be formed by combining two or more kinds of charge generating agents. For example, for a digital optical system image forming apparatus (for example, a laser beam printer using a light source such as a semiconductor laser or a facsimile), it is preferable to use a photoconductor having sensitivity in a wavelength region of 700 nm or more. In order to form such a photoreceptor, it is preferable to use a phthalocyanine pigment (for example, X-type metal-free phthalocyanine (x-H ₂ Pc) or Y-type titanyl phthalocyanine (Y-TiOPc)) as a charge generator. In an image forming apparatus using a short wavelength laser light source, it is preferable to use a photoreceptor having sensitivity in a short wavelength region (for example, a wavelength of 350 nm or more and 550 nm or less). In order to form such a photoreceptor, it is preferable to use an anthanthrone pigment or a perylene pigment as a charge generator.

  Examples of the charge generating agent may be described as phthalocyanine pigments represented by formulas (CGM-1) to (CGM-4) (hereinafter referred to as phthalocyanine pigments (CGM-1) to (CGM-4)). ).

  The content of the charge generating agent is preferably 5 parts by mass or more and 1,000 parts by mass or less, and more preferably 30 parts by mass or more and 500 parts by mass or less with respect to 100 parts by mass of the base resin.

[2-1-2. Base resin]
The base resin is not particularly limited as long as it can be applied to the photoreceptor. Examples of the base resin include a thermoplastic resin, a thermosetting resin, and a photocurable resin. Examples of the thermoplastic resin include styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic copolymer, styrene-acrylic acid copolymer, polyethylene resin, and ethylene-acetic acid. Vinyl copolymer, chlorinated polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer resin, vinyl chloride-vinyl acetate copolymer, alkyd resin, polyamide resin, polyurethane resin, polysulfone resin, diallyl phthalate resin, ketone resin, polyvinyl Examples include acetal resin, polyvinyl butyral resin, and polyether resin. Examples of the thermosetting resin include silicone resin, epoxy resin, phenol resin, urea resin, and melamine resin. Examples of the photocurable resin include an epoxy acrylic acid resin or a urethane-acrylic acid resin. Of these base resins, polyvinyl acetal resins are preferred. As these base resins, one kind of base resin may be used alone, or two or more kinds thereof may be used in combination.

  As the base resin, a resin similar to the binder resin described later is exemplified, but in the same photoreceptor, a resin different from the binder resin is usually selected. This is due to the following reason. When manufacturing a photoreceptor, usually, a charge transport layer is formed on the charge generation layer after the charge generation layer is formed. For this reason, the charge transport layer coating solution is applied to the charge generation layer. This is because it is required that the base resin of the charge generation layer is not dissolved in the solvent of the charge transport layer coating solution when the charge transport layer is formed. Therefore, as the base resin, a resin different from the binder resin is usually selected for the same photoreceptor.

[2-2. Charge transport layer]
The charge transport layer includes, for example, an electron transport agent, a binder resin, and silica particles. The thickness of the charge transport layer is not particularly limited as long as it can sufficiently function as the charge transport layer. Specifically, the thickness of the charge transport layer is preferably 2 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less. The charge transport layer may contain a hole transport agent. Hereinafter, the electron transport agent, the hole transport agent, the binder resin, and the silica particles will be described.

(2-2-1. Electron transport agent)
In the photoreceptor according to the exemplary embodiment, the electron transport agent includes a compound represented by the general formula (1), (2), or (3). When the charge transport layer contains the compound represented by the general formula (1), (2) or (3) as an electron transport agent, both the oil crack resistance and the wear resistance of the photoreceptor can be achieved.

In general formula (1), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ are each independently a hydrogen atom, an alkoxy group having 1 to 8 carbon atoms, It represents a phenyl group or an alkyl group having 1 to 8 carbon atoms which may be substituted.

In the general formula (2), R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ and R ₁₈ are each independently a hydrogen atom, an alkoxy group having 1 to 8 carbon atoms, It represents a phenyl group or an alkyl group having 1 to 8 carbon atoms which may be substituted.

In general formula (3), R ₂₁ and R ₂₂ are each independently a hydrogen atom, an alkoxy group having 1 to 8 carbon atoms, a phenyl group, or an alkyl having 1 to 8 carbon atoms that may be substituted. Represents a group.

In general formula (1), the alkyl group having 1 to 8 carbon atoms represented by R _{1 to} R ₈ is preferably an alkyl group having 1 to 4 carbon atoms, which is a methyl group or a t-butyl group. More preferably. In general formula (1), the alkyl group having 1 to 8 carbon atoms represented by R _{1 to} R ₈ may be substituted with a substituent. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, or a cyano group. In general formula (1), R _{1 to} R ₈ each independently preferably represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and represents a hydrogen atom, a methyl group, or a t-butyl group. It is more preferable to represent.

In general formula (2), the alkyl group represented by R _{11 to} R ₁₈ is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or a t-butyl group. In general formula (2), the alkyl group having 1 to 8 carbon atoms represented by R _{11 to} R ₁₈ may be substituted with a substituent. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, or a cyano group. In the general formula (2), R ₁₁ ~R ₁₈ each independently represent a hydrogen atom, or preferably represents an alkyl group having a carbon number of 1 to 4, hydrogen atom, methyl group, or t- butyl group More preferably it represents.

In general formula (3), the alkyl group having 1 to 8 carbon atoms represented by R ₂₁ and R ₂₂ is preferably an alkyl group having 1 to 5 carbon atoms, and preferably a t-pentyl group. More preferred. In general formula (3), the alkyl group having 1 to 8 carbon atoms represented by R ₂₁ and R ₂₂ may be substituted with a substituent. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, or a cyano group. In general formula (3), R ₂₁ and R ₂₂ each independently preferably represent an alkyl group having 1 to 5 carbon atoms, and more preferably a t-pentyl group.

  Preferable examples of the compound represented by the general formula (1) include compounds represented by the formulas (ETM-1) to (ETM-2) (hereinafter referred to as electron transfer agents (ETM-1) to (ETM-2). ) May be described.

  Preferable examples of the compound represented by the general formula (2) include compounds represented by the formulas (ETM-3) to (ETM-4) (hereinafter referred to as electron transfer agents (ETM-3) to (ETM-4)). May be described).

  Preferable examples of the compound represented by the general formula (3) include a compound represented by the formula (ETM-5) (hereinafter sometimes referred to as an electron transport agent (ETM-5)).

  The electron transport agent can include a compound other than the compound represented by the general formula (1), (2) or (3) (hereinafter, may be referred to as other electron transport agent). Other electron transport agents are not particularly limited as long as they can be applied to the photoreceptor. Examples of other electron transporting agents include quinone compounds (quinone compounds other than the compounds represented by formula (1), (2) or (3)), diimide compounds, hydrazone compounds, malononitrile compounds. Thiopyran compounds, trinitrothioxanthone compounds, 3,4,5,7-tetranitro-9-fluorenone compounds, dinitroanthracene compounds, dinitroacridine compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone , Dinitrobenzene, dinitroacridine, succinic anhydride, maleic anhydride, or dibromomaleic anhydride. Examples of quinone compounds include diphenoquinone compounds, azoquinone compounds, anthraquinone compounds, naphthoquinone compounds, nitroanthraquinone compounds, and dinitroanthraquinone compounds. These electron transfer agents may be used alone or in combination of two or more.

  Examples of other electron transporting agents may be described as compounds represented by formulas (ETM-6) to (ETM-7) (hereinafter referred to as electron transporting agents (ETM-6) to (ETM-7)). ).

  The content of the electron transport agent in the charge transport layer is preferably 0.1 parts by mass or more and 20 parts by mass or less, and 0.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the binder resin. Is more preferable.

(2-2-2. Hole transport agent)
The hole transport agent is not particularly limited as long as it can be applied to the photoreceptor. As the hole transport agent, for example, a nitrogen-containing cyclic compound or a condensed polycyclic compound can be used. Examples of the nitrogen-containing cyclic compound and the condensed polycyclic compound include triphenylamine derivatives; diamine derivatives (for example, N, N, N ′, N′-tetraphenylbenzidine derivatives, N, N, N ′, N ′). -Tetraphenylphenylenediamine derivative, N, N, N ', N'-tetraphenylnaphthylenediamine derivative, or di (aminophenylethenyl) benzene derivative, or N, N, N', N'-tetraphenylphenanthri Range amine derivatives); oxadiazole compounds (eg, 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole); styryl compounds (eg, 9- (4-diethylaminostyryl) ) Anthracene); carbazole compounds (for example, polyvinyl carbazole); organic polysilane compounds; pyrazoline compounds ( For example, 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline); hydrazone compound; indole compound; oxazole compound; isoxazole compound; thiazole compound; thiadiazole compound; imidazole compound; Or triazole compounds. These hole transport agents may be used alone or in combination of two or more.

  Among these hole transport agents, a hole transport agent containing a compound having two or more styryl groups and one or more aryl groups is preferable. Examples of such hole transporting agents include compounds represented by general formula (4), (5), (6) or (7).

In general formula (4), Q ₁ is substituted with a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or an alkyl group having 1 to 8 carbon atoms. Represents an optionally substituted phenyl group. Q ₂ each independently represents an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a phenyl group. Q ₃ , Q ₄ , Q ₅ , Q ₆ and Q ₇ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a phenyl group. Represent. Two adjacent ones of Q ₃ , Q ₄ , Q ₅ , Q ₆ , and Q ₇ may be bonded to each other to form a ring. a represents an integer of 0 or more and 5 or less. When a represents an integer of 2 or more and 5 or less, a plurality of Q ₂ bonded to the same phenyl group may be the same or different from each other.

In the general formula (5), Q ₈ , Q ₁₀ , Q ₁₁ , Q ₁₂ , Q ₁₃ , and Q ₁₄ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or 1 or more carbon atoms. It represents an alkoxy group of 8 or less or a phenyl group. Q ₉ and Q ₁₅ each independently represents an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a phenyl group. b represents an integer of 0 or more and 5 or less. When b represents an integer of 2 or more and 5 or less, a plurality of Q ₉ bonded to the same phenyl group may be the same as or different from each other. c represents an integer of 0 or more and 4 or less. When c represents an integer of 2 or more and 4 or less, the plurality of Q ₁₅ bonded to the same phenyl group may be the same as or different from each other. k represents 0 or 1 each independently.

In general formula (6), R _a , R _b and R _c each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a phenyl group, or an alkoxy group having 1 to 8 carbon atoms. Represent. q independently represents an integer of 0 or more and 4 or less. When q represents an integer of 2 or more and 4 or less, a plurality of R _c bonded to the same phenyl group may be the same or different from each other. m and n each independently represent an integer of 0 or more and 5 or less. When m represents an integer of 2 or more and 5 or less, a plurality of R _b bonded to the same phenyl group may be the same or different from each other. When n represents an integer of 2 or more and 5 or less, a plurality of R _a bonded to the same phenyl group may be the same or different from each other.

In General Formula (7), Ar ₁ is substituted with one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a phenoxy group, and an alkoxy group having 1 to 6 carbon atoms. Or an aryl group that may be substituted, or an alkyl group having 1 to 6 carbon atoms, a phenoxy group, and one or more substituents selected from the group consisting of alkoxy groups having 1 to 6 carbon atoms. Represents a good heterocyclic group. Ar ₂ may be independently substituted with one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a phenoxy group, and an alkoxy group having 1 to 6 carbon atoms. Represents a good aryl group.

In general formula (4), the phenyl group represented by Q ₁ is preferably a phenyl group substituted with an alkyl group having 1 to 8 carbon atoms, more preferably a phenyl group substituted with a methyl group. preferable.

In general formula (4), the alkyl group having 1 to 8 carbon atoms represented by Q ₂ is preferably an alkyl group having 1 to 6 carbon atoms, and is an alkyl group having 1 to 4 carbon atoms. More preferably, it is more preferably a methyl group. It is preferable that a represents 0 or 1.

In general formula (4), the alkyl group having 1 to 8 carbon atoms represented by Q _{3 to} Q ₇ is preferably an alkyl group having 1 to 4 carbon atoms, and may be a methyl group, an ethyl group, or n. -It is more preferable that it is a butyl group. In general formula (4), the alkoxy group having 1 to 8 carbon atoms represented by Q _{3 to} Q ₇ is preferably a methoxy group. In general formula (4), Q _{3 to} Q ₇ preferably each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms, More preferably, it represents an atom, an alkyl group having 1 to 4 carbon atoms, or a methoxy group.

In the general formula (4), two adjacent Q _{3 to} Q ₇ are bonded to each other to form a ring (more specifically, a benzene ring or a cycloalkane having 5 to 7 carbon atoms). May be. For example, Q ₆ and Q ₇ adjacent to each other among Q _{3 to} Q ₇ may be bonded to each other to form a benzene ring or a cycloalkane having 5 to 7 carbon atoms. When two adjacent Q _{3 to} Q ₇ are bonded to each other to form a benzene ring, this benzene ring is condensed with a phenyl group to which Q _{3 to} Q ₇ are bonded to form a bicyclic condensed ring group (naphthyl group). Form. When two adjacent Q _{3 to} Q ₇ are bonded to each other to form a cycloalkane having 5 to 7 carbon atoms, Q _{3 to} Q ₇ are bonded to the cycloalkane having 5 to 7 carbon atoms. To form a bicyclic fused ring group. In this case, the condensation site between the cycloalkane having 5 to 7 carbon atoms and the phenyl group may contain a double bond. Two adjacent Q _{3 to} Q ₇ are preferably bonded to each other to form a cycloalkane having 5 to 7 carbon atoms, more preferably cyclohexane.

In the general formula (4), each Q ₁ preferably independently represents a hydrogen atom or a phenyl group substituted with an alkyl group having 1 to 8 carbon atoms. Q ₂ preferably represents an alkyl group having 1 to 8 carbon atoms. Q _{3 to} Q ₇ each independently preferably represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms. It is preferable that two adjacent Q _{3 to} Q ₇ are bonded to each other to form a ring. It is preferable that a represents 0 or 1.

In general formula (5), the alkyl group having 1 to 8 carbon atoms represented by Q ₈ and Q _{10 to} Q ₁₄ is preferably an alkyl group having 1 to 4 carbon atoms, and may be a methyl group or an ethyl group. It is preferable that In general formula (5), Q ₈ and Q _{10 to} Q ₁₄ preferably each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group. In general formula (5), b and c preferably represent 0.

In general formula (6), the alkyl group having 1 to 4 carbon atoms represented by R _a and R _b is preferably an alkyl group having 1 to 4 carbon atoms, and represents a methyl group or an ethyl group. Is more preferable. It is preferable that m and n each independently represent an integer of 0 or more and 2 or less. q preferably represents 0.

In the general formula (6), examples of the aryl group represented by Ar ¹ include an aryl group having 6 to 14 carbon atoms. In general formula (6), the aryl group represented by Ar ¹ may be substituted with a substituent. Such a substituent is a substituent selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a phenoxy group, and an alkoxy group having 1 to 6 carbon atoms. In general formula (6), the aryl group represented by Ar ₁ is preferably a phenyl group substituted with an alkyl group having 1 to 4 carbon atoms, and is a phenyl group substituted with a methyl group and an ethyl group. It is more preferable. In general formula (6), the aryl group represented by Ar ₂ preferably represents a phenyl group.

In the general formula (6), the heterocyclic group represented by Ar ₁ includes, for example, one or more (preferably one to three) heteroatoms and a 5-membered or 6-membered monocycle having aromaticity. A heterocyclic group in which such single rings are condensed; or a heterocyclic group in which such a single ring is condensed with a 5-membered or 6-membered hydrocarbon ring. The hetero atom is at least one selected from the group consisting of a nitrogen atom, a sulfur atom, and an oxygen atom. Specific examples of the heterocyclic group include thiophenyl group, furanyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, isothiazolyl group, isoxazolyl group, oxazolyl group, isoxazolyl group, thiazolyl group, isothiazolyl group, furazanyl group, pyranyl group, pyridyl group. , Pyridazinyl group, pyrimidinyl group, pyrazinyl group, indolyl group, 1H-indazolyl group, isoindolyl group, chromenyl group, quinolinyl group, isoquinolinyl group, purinyl group, pteridinyl group, triazolyl group, tetrazolyl group, 4H-quinolidinyl group, naphthyridinyl group, A benzofuranyl group, a 1,3-benzodioxolyl group, a benzoxazolyl group, a benzothiazolyl group, or a benzimidazolyl group can be mentioned. In general formula (V), the heterocyclic group represented by Ar ₁ may be substituted with a substituent. Such a substituent is a substituent selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a phenoxy group, and an alkoxy group having 1 to 6 carbon atoms.

  Preferable examples of the compound represented by the general formula (4) include compounds represented by the formulas (HTM-1) to (HTM-4) (hereinafter referred to as hole transporting agents (HTM-1) to (HTM- 4) may be mentioned.

  Preferable examples of the compound represented by the general formula (5) include compounds represented by the formulas (HTM-5) to (HTM-7) (hereinafter referred to as hole transport agents (HTM-5) to (HTM-). 7)).

  Preferable examples of the compound represented by the general formula (6) include compounds represented by the formulas (HTM-8) to (HTM-9) (hereinafter referred to as hole transport agents (HTM-8) to (HTM-). 9))).

  Preferable examples of the compound represented by the general formula (7) include a compound represented by the formula (HTM-10) (hereinafter may be referred to as a hole transport agent (HTM-10)).

  As hole transporting agents other than the compounds represented by the general formulas (4) to (7), compounds represented by the formulas (HTM-11) to (HTM-12) (hereinafter referred to as hole transporting agent (HTM-)). 11) to (HTM-12)).

  The content of the hole transport agent in the charge transport layer of the photoreceptor is preferably 10 parts by mass or more and 200 parts by mass or less, and 20 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the binder resin. Is more preferable.

[2-2-3. Binder resin]
The binder resin binds a material in the charge transport layer (for example, an electron transport agent or silica particles). The binder resin preferably contains a polycarbonate resin. As a suitable example of the polycarbonate resin contained in the binder resin, a resin represented by the formula (Resin-1) or (Resin-2) (hereinafter, polycarbonate resin (Resin-1) or polycarbonate resin (Resin-2)) Or a resin having a repeating unit represented by (Resin-3) (hereinafter, sometimes referred to as polycarbonate resin (Resin-3)). In addition, the subscripts (20, 80) in the formulas (Resin-1) and (Resin-2) each indicate the ratio (mol%) of the repeating structural unit in the polycarbonate resin.

  The binder resin may contain only a polycarbonate resin or may contain a resin other than the polycarbonate resin. The content of the polycarbonate resin in the binder resin is preferably 95% by mass or more, and more preferably 100% by mass.

  Hereinafter, resins other than the polycarbonate resin will be exemplified. For example, suitable examples of the thermoplastic resin contained in the binder resin include styrene resin, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, styrene-acrylic acid copolymer. Polymer, acrylic copolymer, polyethylene resin, ethylene-vinyl acetate copolymer, chlorinated polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer, vinyl chloride-vinyl acetate copolymer, polyester resin, alkyd resin, polyamide resin , Polyurethane resin, polyarylate resin, polysulfone resin, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, or polyester resin. Moreover, as a suitable example of the thermosetting resin contained in binder resin, a silicone resin, an epoxy resin, a phenol resin, a urea resin, or a melamine resin is mentioned. Moreover, as a suitable example of the photocurable resin contained in binder resin, an epoxy acrylic resin or a urethane-acrylic resin is mentioned. One kind of resin may be used alone, or two or more kinds of resins may be used in combination.

  The viscosity average molecular weight of the binder resin is preferably 40,000 or more, and more preferably 40,000 or more and 60,000 or less. When the viscosity average molecular weight of the binder resin is 40,000 or more, the photoconductor tends to have high wear resistance. For this reason, it becomes possible to suppress wear of the charge transport layer of the photoreceptor. In addition, when the binder resin has a viscosity average molecular weight of 60,000 or less, the binder resin tends to have appropriate solubility. Therefore, the charge transport layer is formed using a non-halogen polar solvent or a non-polar solvent. It is easy to prepare a coating solution for forming.

[2-2-4. Silica particles]
Content of the silica particle contained in a charge transport layer is 0.5 to 15.0 parts by mass with respect to 100.0 parts by mass of the binder resin. By including an appropriate amount of silica particles in the outermost surface layer of the photosensitive layer, it is possible to obtain a photoreceptor that can achieve both wear resistance and oil crack resistance.

  Use particles other than silica particles (for example, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, indium oxide doped with tin, tin oxide doped with antimony or tantalum, or zirconium oxide) In comparison with the case where the silica particles are used, when the silica particles are used, a photosensitive layer excellent in abrasion resistance and oil crack resistance tends to be obtained. Silica particles can be produced at low cost. Silica particles can be easily surface-treated and the particle diameter can be easily adjusted.

  The surface of the silica particles is preferably treated with a surface treatment agent in order to improve wear resistance and oil crack resistance. Examples of the surface treatment agent include hexamethyldisilazane, N-methyl-hexamethyldisilazane, and hexamethyl-N-propyldisilazane. Of these, hexamethyldisilazane is preferred. Hexamethyldisilazane has good reactivity with the hydroxyl groups on the surface of the silica particles. When the silica particles are surface-treated with hexamethyldisilazane, the hydroxyl groups on the surface of the silica particles can be easily reduced. As a result, it is possible to suppress a decrease in electrical characteristics of the silica particles due to moisture (humidity). Further, by using hexamethyldisilazane as the surface treatment agent, it is possible to suppress the release of the surface treatment agent from the surface of the silica particles. By suppressing the release of the surface treatment agent, it is possible to suppress charge traps (and hence a decrease in sensitivity due to the charge traps) caused by the released surface treatment agent.

  When the surface of the silica particles is surface-treated using a surface treatment agent such as hexamethyldisilazane, hydroxyl groups on the silica surface are silylated, and the surface of the silica particles has a site represented by the general formula (8).

In the general formula (8), R ₃₁ , R ₃₂ and R ₃₃ each independently represents an alkyl group or an aryl group. Examples of the alkyl group represented by R ₃₁ , R ₃₂ and R ₃₃ include an alkyl group having 1 to 6 carbon atoms, and an alkyl group having 1 to 4 carbon atoms is preferable. Examples of the aryl group represented by R ₃₁ , R ₃₂ and R ₃₃ include an aryl group having 6 to 14 carbon atoms.

Furthermore, in the general formula (8), it is more preferable that R ₃₁ , R ₃₂ and R ₃₃ each represent a methyl group. This preferred example corresponds to the case where the surface treatment agent is hexamethyldisilazane.

  The particle diameter (average primary particle diameter) of the silica particles is 50 nm or more and 150 nm or less. When the particle diameter of the silica particles is 50 nm or more, there is a tendency that the wear resistance is excellent. On the other hand, when the particle diameter of the silica particles is 150 nm or less, the dispersibility of the silica particles in the binder resin tends to be high.

The average primary particle size of the silica particles is measured by the following method. Silica (powder that is a plurality of silica particles) is used as a measurement sample. The N ₂ adsorption isotherm at −196 ° C. of the measurement sample is measured. The obtained N ₂ adsorption isotherm is evaluated according to the method of Brunauer, Emmett and Teller, and further according to the t curve method by De Boer. Thereby, the specific surface area of the measurement sample is calculated. From the specific surface area of the obtained measurement sample, the particle size of the measurement sample is calculated according to the formula “S = 6 / ρd”. In the formula, S represents the specific surface area of the measurement sample, ρ represents the density of the measurement sample, and d represents the particle size of the measurement sample. The calculated particle diameter of the measurement sample is defined as the average primary particle diameter of the silica particles. In addition, as another method for measuring the average primary particle size of silica particles, for example, a method of taking an image of a measurement sample using a transmission electron microscope and calculating the average primary particle size from the obtained image is also mentioned. It is done.

[2-3. Additive]
In the photoreceptor according to the exemplary embodiment, at least one of the photosensitive layer (charge generation layer and charge transport layer) and the intermediate layer may contain various additives. Suitable examples of additives include deterioration inhibitors (antioxidants, radical scavengers, quenchers, or UV absorbers), softeners, surface modifiers, extenders, thickeners, dispersion stabilizers, waxes. , Acceptors, donors, surfactants, or leveling agents. Hereinafter, sensitizers, pigments, plasticizers, and antioxidants will be described.

[2-3-1. Sensitizer]
In order to improve the sensitivity of the charge generation layer, a sensitizer (for example, terphenyl, halonaphthoquinones, or acenaphthylene) may be included in the charge generation layer.

[2-3-2. Pigment]
The charge transport layer may further contain a pigment. By using silica particles and a pigment together in the charge transport layer, the electrical characteristics of the photoreceptor in a low temperature and low humidity environment (for example, temperature: 10 ° C., humidity: 35% RH) tend to be improved. Examples of the pigment contained in the charge transport layer include phthalocyanine pigments, perylene pigments, bisazo pigments, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, trisazo pigments, and indigo pigments. Azulenium pigments, cyanine pigments, ansanthrone pigments, triphenylmethane pigments, selenium pigments, toluidine pigments, pyrazoline pigments, or quinacridone pigments. Examples of phthalocyanine pigments include metal-free phthalocyanine pigments (more specifically, X-type metal-free phthalocyanine (x-H ₂ Pc) pigments), Y-type titanyl phthalocyanine (Y-TiOPc) pigments, α-type titanyl phthalocyanine ( α-TiOPc) pigment and ε-type copper phthalocyanine (ε-CuPc) pigment. Of these pigments, phthalocyanine pigments are preferred, and metal-free phthalocyanine pigments or titanyl phthalocyanine pigments are more preferred.

  More preferably, the metal-free phthalocyanine pigment has a main peak at a Bragg angle (2θ ± 0.2 °) of 27.2 ° in the CuKα characteristic X-ray diffraction spectrum. Examples of such metal-free phthalocyanine include X-type metal-free phthalocyanine. The titanyl phthalocyanine pigment has a main peak at a Bragg angle (2θ ± 0.2 °) of 27.2 ° or a Bragg angle (2θ ± 0.2 °) of 28.6 in a CuKα characteristic X-ray diffraction spectrum. It is more preferable to have °. Examples of such titanyl phthalocyanine include Y-type titanyl phthalocyanine. The main peak corresponds to a diffraction peak having the first or second highest intensity in a range where the Bragg angle (2θ ± 0.2 °) is 3 ° or more and 40 ° or less. The main peak can be read from the X-ray diffraction spectrum. The X-ray diffraction spectrum can be measured using an X-ray diffraction apparatus (“RINT (registered trademark) 1100” manufactured by Rigaku Corporation). The method for measuring the X-ray diffraction spectrum will be described in detail in Examples.

[2-3-3. Plasticizer]
In order to improve the oil crack resistance of the charge transport layer, the charge transport layer may contain a plasticizer. Preferable examples of the plasticizer include biphenyl derivatives. Preferable examples of the biphenyl derivative include compounds represented by formulas (BP-1) to (BP-20).

[2-3-4. Antioxidant]
The charge transport layer may contain an antioxidant. Examples of the antioxidant include hindered phenol compounds, hindered amine compounds, thioether compounds, and phosphite compounds. Among these antioxidants, hindered phenol compounds and hindered amine compounds are preferred.

  The addition amount of the antioxidant in the charge transport layer is preferably 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the binder resin. When the addition amount of the antioxidant is within such a range, it is easy to suppress deterioration of electrical characteristics due to oxidation of the photoreceptor.

[3. Middle layer]
The photoreceptor according to the exemplary embodiment may include an intermediate layer (for example, an undercoat layer). The intermediate layer preferably contains a resin (interlayer resin) used for the intermediate layer and inorganic particles. When the intermediate layer having such a configuration is interposed between the conductive substrate and the photosensitive layer, it is possible to maintain an insulating property that can suppress the occurrence of leakage. Further, the flow of current generated when the photosensitive member is exposed can be smoothed to suppress an increase in electrical resistance. The intermediate layer resin is not particularly limited as long as it can be used as a resin for forming the intermediate layer.

  Examples of inorganic particles include metal (for example, aluminum, iron, or copper), metal oxide (for example, titanium oxide, alumina, zirconium oxide, tin oxide, or zinc oxide) particles, or non-metal oxide (more Specific examples thereof include silica) particles. These inorganic particles may be used individually by 1 type, or may be used in combination of 2 or more type.

[4. Photoconductor manufacturing method]
A method for manufacturing the photoreceptor will be described. The method for producing a photoreceptor includes, for example, a photosensitive layer forming step. The photoreceptor forming step includes a charge generation layer forming step and a charge transport layer forming step.

[4-1. Charge generation layer forming step]
In the charge generation layer forming step, first, a coating liquid for forming the charge generation layer (hereinafter, sometimes referred to as a charge generation layer coating liquid) is prepared. A charge generation layer coating solution is applied onto the conductive substrate. Next, at least a part of the solvent contained in the applied charge generation layer coating solution is removed by drying by an appropriate method. As a result, a charge generation layer is formed on the conductive substrate. The charge generation layer coating solution includes, for example, a charge generation agent, a base resin, and a solvent. Such a charge generation layer coating solution is prepared by dissolving or dispersing a charge generation agent and a base resin in a solvent. Various additives (for example, a surfactant or a leveling agent) may be added to the coating solution for the charge generation layer as necessary.

[4-2. Charge transport layer forming step]
In the charge transport layer forming step, first, a coating liquid for forming the charge transport layer (hereinafter, sometimes referred to as a charge transport layer coating liquid) is prepared. A charge transport layer coating solution is applied onto the charge generation layer. Next, at least a part of the solvent contained in the applied charge transport layer coating solution is removed by drying by an appropriate method. Thereby, a charge transport layer is formed on the charge generation layer. The coating solution for the charge transport layer contains an electron transport agent, a binder resin, silica particles, and a solvent. Such a coating liquid for a charge transport layer can be prepared by dissolving or dispersing an electron transport agent, a binder resin, and silica particles in a solvent. Various additives (for example, a surfactant or a leveling agent) may be added to the charge transport layer coating solution as necessary.

  Hereinafter, the charge generation layer forming step and the charge transport layer forming step will be described as examples, and the details of the photosensitive layer forming step will be described.

  The solvent contained in the charge generation layer coating solution and the charge transport layer coating solution is not particularly limited as long as each component contained in the charge generation layer coating solution and the charge transport layer coating solution can be dissolved or dispersed. Specifically, examples of the solvent include alcohols (methanol, ethanol, isopropanol, or butanol), aliphatic hydrocarbons (n-hexane, octane, or cyclohexane), and aromatic hydrocarbons (benzene, toluene, or xylene). , Halogenated hydrocarbons (dichloromethane, dichloroethane, carbon tetrachloride, or chlorobenzene), ethers (dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, or diethylene glycol dimethyl ether), ketones (acetone, methyl ethyl ketone, or cyclohexanone), esters (Ethyl acetate or methyl acetate), dimethylformaldehyde, dimethylformamide, or dimethyl sulfoxide. These solvents may be used alone or in combination of two or more. Of these solvents, non-halogen solvents are preferably used.

  Furthermore, the solvent contained in the charge transport layer coating solution is preferably different from the solvent contained in the charge generation layer coating solution. When producing a photoreceptor, usually, a charge generation layer and a charge transport layer are formed in this order, and therefore a charge transport layer coating solution is applied on the charge generation layer. This is because the charge generation layer is required not to be dissolved in the solvent of the charge transport layer coating solution when the charge transport layer is formed.

  The charge generation layer coating solution and the charge transport layer coating solution are prepared by mixing the respective components and dispersing the mixture in a solvent. For mixing or dispersing, for example, a bead mill, a roll mill, a ball mill, an attritor, a paint shaker, or an ultrasonic disperser can be used.

  The charge generation layer coating solution and the charge transport layer coating solution contain, for example, a surfactant or a leveling agent in order to improve the dispersibility of each component or the surface smoothness of each formed layer. Also good.

  The method for applying the charge generation layer coating solution and the charge transport layer coating solution is not particularly limited as long as the charge generation layer coating solution and the charge transport layer coating solution can be uniformly applied. Examples of the coating method include a dip coating method, a spray coating method, a spin coating method, and a bar coating method.

  As a method for drying at least part of the solvent contained in the charge generation layer coating solution and the charge transport layer coating solution, the solvent in the charge generation layer coating solution and the charge transport layer coating solution can be suitably evaporated. If it is a method, it will not specifically limit. Examples of the removal method include heating, pressurization, or combined use of heating and decompression. More specifically, a method of heat treatment (hot air drying) using a high-temperature dryer or a reduced-pressure dryer can be mentioned. The conditions for the heat treatment are that the treatment temperature is 40 ° C. or more and 150 ° C. or less, and the treatment time is 3 minutes or more and 120 minutes or less.

  Note that the method for manufacturing a photoreceptor may further include a step of forming an intermediate layer as necessary. A known method can be selected as appropriate for the step of forming the intermediate layer.

  As described above, in the photoreceptor according to this embodiment, the charge transfer agent includes the compound represented by the general formula (1), (2), or (3) as the electron transfer agent. The average primary particle size of the silica particles is 50 nm or more and 150 nm or less. Moreover, content of the silica particle contained in a charge transport layer is 0.5 to 15 mass parts with respect to 100 mass parts of binder resin. The photoreceptor having such a configuration can achieve both wear resistance and oil crack resistance. For this reason, the photoreceptor according to the present embodiment can be suitably used in various image forming apparatuses.

  Examples of the present invention will be described below. The present invention is not limited to the examples.

Manufacture of photoconductor [Method of manufacturing photoconductor (A-1)]
Hereinafter, the production of the photoreceptor (A-1) according to Example 1 will be described.

(Formation of intermediate layer)
First, a surface-treated titanium oxide (prototype “SMT-A” manufactured by Teika Co., Ltd., average primary particle size 10 nm) was prepared. Specifically, titanium oxide was surface-treated using alumina and silica, and surface treatment was further performed using methyl hydrogen polysiloxane while wet-dispersing the surface-treated titanium oxide. Thereby, the titanium oxide used for formation of an intermediate | middle layer was obtained.

  Subsequently, 2 parts by mass of titanium oxide (surface-treated titanium oxide) prepared as described above in a solvent containing 10 parts by mass of methanol, 1 part by mass of butanol, and 1 part by mass of toluene are polyamide resin. 1 part by mass of Amilan (registered trademark) (“CM8000” polyamide 6, polyamide 12, polyamide 66, and quaternary copolymer polyamide resin of polyamide 610 manufactured by Toray Industries, Inc.) was added. The material in the solvent was mixed for 5 hours using a bead mill, and the material was dispersed in the solvent. Thereby, the coating liquid for intermediate | middle layers was obtained.

  Subsequently, the obtained intermediate layer coating solution was filtered using a filter having an opening of 5 μm. Subsequently, the intermediate layer coating solution (filtered intermediate layer coating solution) was applied to the surface of an aluminum drum-shaped support (diameter 30 mm, total length 246 mm) using a dip coating method. Subsequently, the applied intermediate layer coating solution was dried at 130 ° C. for 30 minutes. As a result, an intermediate layer (thickness: 1.0 μm) was formed on the conductive substrate (drum-like support).

(Formation of charge generation layer)
In a solvent containing 40 parts by mass of propylene glycol monomethyl ether and 40 parts by mass of tetrahydrofuran, titanyl phthalocyanine (Y-type titanyl) having a main peak at a Bragg angle 2θ ± 0.2 ° = 27.2 ° in a CuKα characteristic X-ray diffraction spectrum. 1.5 parts by mass of phthalocyanine) and 1 part by mass of a polyvinyl acetal resin (“S-LEC BX-5” manufactured by Sekisui Chemical Co., Ltd.) as a base resin are added and mixed for 2 hours using a bead mill. The material was dispersed. As a result, a charge generation layer coating solution was obtained.

  Subsequently, the obtained coating solution for charge generation layer was filtered using a filter having an opening of 3 μm. Subsequently, a charge generation layer coating solution (charge generation layer coating solution after filtration) was applied onto the intermediate layer formed as described above by using a dip coating method. Subsequently, the applied charge generation layer coating solution was dried at 50 ° C. for 5 minutes. As a result, a charge generation layer (thickness 0.3 μm) was formed on the intermediate layer.

(Formation of charge transport layer)
In a solvent containing 350 parts by mass of tetrahydrofuran and 350 parts by mass of toluene, 50 parts by mass of a hole transport agent (HTM-1), 2 parts by mass of an electron transport agent (ETM-1), and a binder resin (Resin-1) ( Viscosity average molecular weight 51,000) 100 parts by mass and silica particles surface-treated with hexamethyldisilazane (HMDS) (“Aerosil (registered trademark) VP RX40S” manufactured by Nippon Aerosil Co., Ltd., average primary particle size 80 nm) 5 mass Part 0.4 parts by mass of an X-type metal-free phthalocyanine pigment (“FASTOGEN Blue 8120BS” manufactured by DIC Corporation) and a hindered phenol-based antioxidant (“Irganox (registered trademark) 1010” manufactured by BASF Corporation) 2 Parts by weight were added. These were mixed for 12 hours using a circulating ultrasonic dispersion device to disperse the material in the solvent. Thereby, the coating liquid for charge transport layers was obtained. The X-type metal-free phthalocyanine pigment had a main peak at a Bragg angle 2θ ± 0.2 ° = 27.2 ° in a CuKα characteristic X-ray diffraction spectrum.

  Subsequently, the obtained coating liquid for charge transport layer was filtered using a filter having an opening of 3 μm. Subsequently, a charge transport layer coating solution (filtered charge transport layer coating solution) was applied onto the charge generation layer formed as described above using a dip coating method. Subsequently, the applied charge transport layer coating solution was dried at 120 ° C. for 40 minutes. As a result, a charge transport layer (thickness 30 μm) was formed on the charge generation layer. As a result, a photoreceptor (A-1) was obtained in which an intermediate layer, a charge generation layer, and a charge transport layer were laminated in this order on a conductive substrate.

[Method for Producing Photosensitive Member (A-2)]
A photoconductor (A-2) is produced in the same manner as the photoconductor (A-1) except that the hole transfer agent (HTM-2) is used instead of the hole transfer agent (HTM-1). did.

[Method for Producing Photoconductor (A-3)]
A photoconductor (A-3) is produced in the same manner as the photoconductor (A-1) except that the hole transfer agent (HTM-3) is used instead of the hole transfer agent (HTM-1). did.

[Method for Producing Photosensitive Member (A-4)]
A photoconductor (A-4) is produced in the same manner as the photoconductor (A-1) except that the hole transfer agent (HTM-4) is used instead of the hole transfer agent (HTM-1). did.

[Method for Producing Photosensitive Member (A-5)]
A photoconductor (A-5) is produced in the same manner as the photoconductor (A-1) except that the hole transfer agent (HTM-5) is used instead of the hole transfer agent (HTM-1). did.

[Method for Producing Photosensitive Member (A-6)]
A photoconductor (A-6) is produced in the same manner as the photoconductor (A-1) except that the hole transfer agent (HTM-6) is used instead of the hole transfer agent (HTM-1). did.

[Method for Producing Photoreceptor (A-7)]
A photoconductor (A-7) is produced in the same manner as the photoconductor (A-1) except that the hole transfer agent (HTM-7) is used instead of the hole transfer agent (HTM-1). did.

[Method for Producing Photoreceptor (A-8)]
A photoconductor (A-8) is produced in the same manner as the photoconductor (A-1) except that the hole transfer agent (HTM-8) is used instead of the hole transfer agent (HTM-1). did.

[Method for producing photoconductor (A-9)]
A photoconductor (A-9) is produced in the same manner as the photoconductor (A-1) except that the hole transfer agent (HTM-9) is used instead of the hole transfer agent (HTM-1). did.

[Method for Producing Photosensitive Member (A-10)]
A photoconductor (A-10) is produced in the same manner as the photoconductor (A-1) except that the hole transfer agent (HTM-10) is used instead of the hole transfer agent (HTM-1). did.

[Method for Producing Photosensitive Member (A-11)]
A photoconductor (A-11) is produced in the same manner as the photoconductor (A-1) except that the hole transfer agent (HTM-11) is used instead of the hole transfer agent (HTM-1). did.

[Method for Producing Photoconductor (A-12)]
A photoconductor (A-12) is produced in the same manner as the photoconductor (A-1) except that the hole transfer agent (HTM-12) is used instead of the hole transfer agent (HTM-1). did.

[Method for Producing Photosensitive Member (A-13)]
A photoconductor (A-13) was produced in the same manner as the photoconductor (A-1) except that the electron transfer agent (ETM-2) was used instead of the electron transfer agent (ETM-1).

[Method for Producing Photosensitive Member (A-14)]
A photoconductor (A-14) was produced in the same manner as the photoconductor (A-1) except that the electron transfer agent (ETM-3) was used instead of the electron transfer agent (ETM-1).

[Method for Producing Photosensitive Member (A-15)]
A photoconductor (A-15) was produced in the same manner as the photoconductor (A-1) except that the electron transfer agent (ETM-4) was used instead of the electron transfer agent (ETM-1).

[Method for Manufacturing Photosensitive Member (A-16)]
A photoconductor (A-16) was produced in the same manner as the photoconductor (A-1) except that the electron transfer agent (ETM-5) was used instead of the electron transfer agent (ETM-1).

[Method for Producing Photosensitive Member (A-17)]
The photoconductor is the same as the photoconductor (A-1) except that a Y-type titanyl phthalocyanine (Y-TiOPc) pigment is used instead of the X-type metal-free phthalocyanine pigment as the pigment to be added to the charge transport layer. (A-17) was produced. This Y-type titanyl phthalocyanine pigment had a main peak at a Bragg angle of 2θ ± 0.2 ° = 27.2 ° in a CuKα characteristic X-ray diffraction spectrum.

[Method for Producing Photosensitive Member (A-18)]
The photoconductor is the same as the photoconductor (A-1) except that an α-type titanyl phthalocyanine (α-TiOPc) pigment is used instead of the X-type metal-free phthalocyanine pigment as the pigment to be added to the charge transport layer. (A-18) was produced.

[Method for Producing Photosensitive Member (A-19)]
The photoconductor is the same as the photoconductor (A-1) except that an ε-type copper phthalocyanine (ε-CuPc) pigment is used in place of the X-type metal-free phthalocyanine pigment as the pigment to be added to the charge transport layer. (A-19) was produced.

[Method for Producing Photosensitive Member (A-20)]
A method similar to that of the photoreceptor (A-1) except that (Resin-2) (viscosity average molecular weight 50,500) was used instead of the binder resin (Resin-1) (viscosity average molecular weight 51,000). A photoreceptor (A-20) was produced.

[Method for Producing Photosensitive Member (A-21)]
A method similar to that for the photoreceptor (A-1) except that (Resin-3) (viscosity average molecular weight 50,000) was used instead of the binder resin (Resin-1) (viscosity average molecular weight 51,000). A photoreceptor (A-21) was produced.

[Method for Manufacturing Photosensitive Member (A-22)]
Photosensitization is performed in the same manner as for the photoreceptor A-1, except that (Resin-4) (viscosity average molecular weight 40,000) is used instead of the binder resin (Resin-1) (viscosity average molecular weight 51,000). Body (A-22) was produced.

[Method for Producing Photosensitive Member (A-23)]
The same as the photoreceptor (A-1) except that (Resin-5) (viscosity average molecular weight 32,500) was used instead of (Resin-1) (viscosity average molecular weight 51,000) as the binder resin. A photoreceptor (A-23) was produced by the method.

[Method for Manufacturing Photosensitive Member (A-24)]
Instead of silica particles (“Aerosil (registered trademark) VP RX40S” manufactured by Nippon Aerosil Co., Ltd., average primary particle size of 80 nm), silica particles (“Aerosil (registered trademark) NAX50” manufactured by Nippon Aerosil Co., Ltd.), average primary particle size of 50 nm The photoconductor (A-24) was produced in the same manner as the photoconductor (A-1), except that (2) was used.

[Method for Producing Photosensitive Member (A-25)]
A photoconductor except that silica particles (“prototype”, average primary particle size 145 nm) were used instead of silica particles (“Aerosil (registered trademark) VP RX40S” manufactured by Nippon Aerosil Co., Ltd., average primary particle size 80 nm)) A photoconductor (A-25) was produced by the same method as (A-1).

[Method for Manufacturing Photosensitive Member (A-26)]
Instead of silica particles surface-treated with hexamethyldisilazane (HMDS) ("Aerosil (registered trademark) VP RX40S" manufactured by Nippon Aerosil Co., Ltd., average primary particle size of 80 nm), surface treatment was performed with dimethyldichlorosilane (DMDCS). A photoconductor (A-26) was produced in the same manner as the photoconductor (A-1) except that silica particles (“prototype”, average primary particle size 80 nm) were used.

[Method for Producing Photosensitive Member (A-27)]
Instead of silica particles surface-treated with hexamethyldisilazane (HMDS) (“Aerosil (registered trademark) VP RX40S” manufactured by Nippon Aerosil Co., Ltd., average primary particle size 80 nm), surface treatment was performed with polydimethylsiloxane (PDMS). A photoconductor (A-27) was produced in the same manner as the photoconductor (A-1) except that silica particles (“prototype”, average primary particle size 80 nm) were used.

[Method for Manufacturing Photosensitive Member (A-28)]
A photoconductor (A-28) was produced in the same manner as the photoconductor (A-1) except that no pigment was added to the charge transport layer.

[Method for Producing Photosensitive Member (A-29)]
A photoconductor (A-29) was produced in the same manner as the photoconductor (A-1) except that the addition amount of silica particles was changed from 5 parts by mass to 0.5 parts by mass.

[Method for Producing Photosensitive Member (A-30)]
A photoconductor (A-30) was produced in the same manner as the photoconductor (A-1) except that the addition amount of silica particles was changed from 5 parts by mass to 2 parts by mass.

[Method for Producing Photoconductor (A-31)]
A photoconductor (A-31) was produced in the same manner as the photoconductor (A-1) except that the addition amount of silica particles was changed from 5 parts by mass to 10 parts by mass.

[Method for Manufacturing Photosensitive Member (A-32)]
A photoconductor (A-32) was produced in the same manner as the photoconductor (A-1) except that the addition amount of silica particles was changed from 5 parts by mass to 15 parts by mass.

[Method for Producing Photoreceptor (B-1)]
A photoconductor (B-1) was produced in the same manner as the photoconductor (A-1) except that silica particles, an electron transfer agent, and a pigment were not added to the charge transport layer.

[Method for Producing Photoconductor (B-2)]
A photoconductor (B-2) was produced in the same manner as the photoconductor (A-1) except that silica particles and an electron transfer agent were not added to the charge transport layer.

[Method for Producing Photoconductor (B-3)]
A photoconductor (B-3) was produced in the same manner as the photoconductor (A-1) except that no electron transfer agent was added to the charge transport layer.

[Method for Producing Photoreceptor (B-4)]
A photoconductor (B-4) was produced in the same manner as the photoconductor (A-1) except that no silica particles were added to the charge transport layer.

[Method for Producing Photoreceptor (B-5)]
A photoconductor (B-5) was produced in the same manner as the photoconductor (A-1) except that the electron transfer agent (ETM-6) was used instead of the electron transfer agent (ETM-1).

[Method for Manufacturing Photosensitive Member (B-6)]
A photoconductor (B-6) was produced in the same manner as the photoconductor (A-1) except that the electron transfer agent (ETM-7) was used instead of the electron transfer agent (ETM-1).

[Method for Producing Photoreceptor (B-7)]
Surface treatment with hexamethyldisilazane (HMDS) instead of silica particles surface-treated with hexamethyldisilazane (HMDS) (“Aerosil (registered trademark) VP RX40S” manufactured by Nippon Aerosil Co., Ltd., average primary particle size 80 nm)) A photoconductor (B-7) was produced in the same manner as the photoconductor (A-1) except that the produced silica particles (“prototype”, average primary particle size: 170 nm) were used.

[Method for Producing Photoreceptor (B-8)]
Surface treatment with hexamethyldisilazane (HMDS) instead of silica particles surface-treated with hexamethyldisilazane (HMDS) (“Aerosil (registered trademark) VP RX40S” manufactured by Nippon Aerosil Co., Ltd., average primary particle size 80 nm)) The photoconductor (B-8) was prepared in the same manner as the photoconductor (A-1) except that the silica particles ("Aerosil (registered trademark) RX300" manufactured by Nippon Aerosil Co., Ltd., average primary particle size 7 nm) were used. ) Was manufactured.

[Method for Producing Photoreceptor (B-9)]
Surface treatment with hexamethyldisilazane (HMDS) instead of silica particles surface-treated with hexamethyldisilazane (HMDS) (“Aerosil (registered trademark) VP RX40S” manufactured by Nippon Aerosil Co., Ltd., average primary particle size 80 nm)) Except for the silica particles (“Aerosil (registered trademark) RX 50” manufactured by Nippon Aerosil Co., Ltd., average primary particle size 40 nm)), the photoconductor (B- 9) was produced.

[Method for Manufacturing Photosensitive Member (B-10)]
A photoconductor (B-10) was produced in the same manner as the photoconductor (A-1), except that the addition amount of silica particles was changed from 5 parts by mass to 0.3 parts by mass.

[Method for Producing Photoconductor (B-11)]
A photoconductor (B-11) was produced in the same manner as the photoconductor (A-1) except that the addition amount of silica particles was changed from 5 parts by mass to 20 parts by mass.

[Measuring method]
(X-ray diffraction spectrum of pigment)
The X-ray diffraction spectrum was measured using an X-ray diffraction apparatus (“RINT (registered trademark) 1100” manufactured by Rigaku Corporation). Specifically, a sample (pigment) is filled in a sample holder of an X-ray diffractometer (“RINT (registered trademark) 1100” manufactured by Rigaku Corporation), an X-ray tube Cu, a tube voltage 40 kV, a tube current 30 mA, and CuKα. An X-ray diffraction spectrum was measured under the condition of a characteristic X-ray wavelength of 1.542 mm. The measurement range (2θ) was, for example, 3 ° or more and 40 ° or less (start angle: 3 °, stop angle: 40 °), and the scanning speed was 10 ° / min.

[Evaluation method]
Each sample (each of photoconductors (A-1) to (A-32) and photoconductors (B-1) to (B-11)) was evaluated for performance.

(Evaluation of electrical characteristics of photoconductor)
Using a drum sensitivity tester (Gentec Co., Ltd.), the sample (photoreceptor) was charged under the conditions of electrification −800 V and rotation speed 31 rpm. Subsequently, monochromatic light (wavelength 780 nm, exposure 1.0 μJ / cm ² ) extracted from the light of the halogen lamp using a bandpass filter was irradiated on the surface of the sample. The surface potential of the sample after 50 milliseconds had elapsed after irradiation with monochromatic light was measured. The measured surface potential was defined as a residual potential (V _L ). The measurement environment was a temperature of 10 ° C. and a humidity of 15% RH.

(Evaluation of abrasion resistance of photoconductor)
The wear resistance of each sample was evaluated using a charge transport layer coating solution (hereinafter, sometimes referred to as an “evaluation coating solution”) prepared in any production of each sample. Specifically, the evaluation coating solution was applied to a polypropylene sheet (thickness: 0.3 mm) wound around an aluminum pipe (diameter: 78 mm). This was dried at 120 ° C. for 40 minutes. As a result, an evaluation sheet having a thickness of 30 μm was formed on the polypropylene sheet.

  Subsequently, the evaluation sheet was peeled from the polypropylene sheet. And the peeled sheet | seat for evaluation was affixed on the wheel ("S-36" by the Taber company), and it was set as the test piece.

Subsequently, after measuring the mass M _A of the specimen before the abrasion test was conducted wear test for the test piece. Specifically, the test piece was attached to a rotary table of a rotary abrasion tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.). Then, with the wear wheel having a load of 600 gf (“CS-10” manufactured by Taber Co., Ltd.) placed on the test piece, the turntable was rotated at a rotation speed of 60 rpm, and a 1,000-turn wear test was performed.

Subsequently, the mass was measured M _B of the specimen after the abrasion test. Then, to determine the mass change is a abrasion loss of the specimen between before and after the test (= M _A -M _B). The wear resistance of the sample was evaluated based on the obtained wear loss.

(Oil crack resistance of photoconductor)
The surface of the sample (photoreceptor) was pressed with a finger, finger oil was attached at one location, and left for 48 hours (2 days) at a temperature of 23 ° C. and a humidity of 50% RH. Then, the surface of the sample to which finger oil adhered was observed visually and using an optical microscope ("OPTISHOT 300" magnification 50 times manufactured by Nikon Corporation). Specifically, the presence or absence of cracks was confirmed, and the locations where cracks occurred were counted. The oil crack resistance was evaluated according to the following criteria from the obtained crack occurrence location.
A: Generation of cracks was not confirmed visually or with a microscope. That is, there were 0 cracks.
B: The crack generation | occurrence | production location was not able to be confirmed visually but the crack generation | occurrence | production location which can be observed with a microscope was 1 or less.
C: There were 5 or less cracks that could be visually confirmed.
D: There were 6 or more cracks that could be visually confirmed.

[Evaluation results]
Tables 1, 2 and 3 show the materials contained in the charge transport layers of the photoreceptors (A-1) to (A-32) and the photoreceptors (B-1) to (B-11). In Tables 1 to 3, the average primary particle size of the silica particles was measured by the method for measuring the N ₂ adsorption isotherm described in the embodiment. Tables 4 and 5 show the evaluation results (electrical characteristics (sensitivity) of each sample (each of photoconductors (A-1) to (A-32) and photoconductors (B-1) to (B-11))). ), Wear resistance, and oil crack resistance).

  As shown in Table 1, Table 2, and Table 3, in the photoreceptors (A-1) to (A-32), the charge transport layer contained an electron transport agent and silica particles. Specifically, the electron transport agent is any one of electron transport agents (ETM-1) to (ETM-5), and any one of the compounds represented by the general formulas (1) to (3). The average primary particle size of the silica particles was 50 nm or more and 145 nm or less. The content of silica particles was 0.5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the binder resin.

  As shown in Table 3, in the photoreceptors (B-1) to (B-3), the charge transport layer did not contain an electron transport agent. In the photoconductors (B-1) to (B-2) and the photoconductor (B-4), the charge transport layer did not contain silica particles. In the photoreceptors (B-5) to (B-6), the charge transport layer contained an electron transport agent (ETM-6) or an electron transport agent (ETM-7). These electron transfer agents were not compounds represented by the general formulas (1) to (3). In the photoreceptors (B-7) to (B-9), the average primary particle diameter of the silica particles was 7 nm, 40 nm, or 170 nm. In photoreceptors (B-10) to (B-11), the content of silica particles was 0.3 parts by mass or 20 parts by mass with respect to 100 parts by mass of the binder resin.

  As shown in Tables 4 and 5, in the photoreceptors (A-1) to (A-32), the evaluation result of oil crack resistance is any one of A to C, and the wear loss is 4.0 mg or more 6 .6 mg or less. As shown in Table 5, in the photoconductors (B-3), (B-5), (B-6), and (B-11), the oil crack resistance evaluation results were all D. As shown in Table 5, in the photoreceptors (B-1), (B-2), (B-4), and (B-7) to (B-10), the wear loss is 7.1 mg or more. It was 8 mg or less.

  As described above, the photoconductors (A-1) to (A-32) can achieve both oil crack resistance and wear resistance as compared with the photoconductors (B-1) to (B-11).

  As shown in Table 1, in the photoreceptor (A-1), the surface of the silica particles was treated with hexamethyldisilazane. As shown in Table 2, in the photoreceptors (A-26) to (A-27), the surfaces of the silica particles were treated with dimethyldichlorosilane and polydimethylsiloxane, respectively. As shown in Table 4, the evaluation result of the oil crack resistance of the photoreceptor (A-1) was A. As shown in Tables 4 and 5, the evaluation results of the oil crack resistance of the photoreceptors (A-26) to (A-27) were all C. From the above, the photoreceptor (A-1) in which the surface of the silica particles is treated with hexamethyldisilazane is the photoreceptor (A-26) to (A-) in which the surface of the silica particles is treated with other than hexamethyldisilazane. Compared with 27), the oil crack resistance was excellent.

As shown in Tables 1 and 2, in the photoreceptor (A-1) and the photoreceptors (A-17) to (A-19), the charge transport layer is xH ₂ Pc, Y-TiOPc, It contained α-TiOPc or ε-CuPc. As shown in Table 2, in the photoreceptor (A-28), the charge transport layer did not contain a pigment. As shown in Table 4, with respect to the photoreceptor (A-1) and the photoreceptors (A-17) to (A-19), the evaluation result of oil crack resistance was A. As shown in Table 5, in the photoreceptor (A-28), the evaluation result of oil crack resistance was C. From the above, the photoreceptor (A-1) containing the pigment in the charge transport layer and the photoreceptors (A-17) to (A-19) are the photoreceptor (A-28) containing no pigment in the charge transport layer. Compared to the above, the oil crack resistance was excellent.

  As shown in Tables 1 and 2, in the photoreceptor (A-1) and the photoreceptors (A-20) to (A-22), the charge transport layer is formed of polycarbonate resins (Resin-1) to (Resin-4). ). These polycarbonate resins had a viscosity average molecular weight of 40,000 or more and 51,000 or less. As shown in Table 2, in the photoreceptor (A-23), the charge transport layer contained a polycarbonate resin (Resin-5). The viscosity average molecular weight of this polycarbonate resin was 32,500. As shown in Table 4, in the photoconductor (A-1) and the photoconductors (A-20) to (A-22), the evaluation result of oil crack resistance was A or B. As shown in Table 4, in the photoreceptor (A-23), the oil crack resistance evaluation result was C. From the above, the photoconductor (A-1) and the photoconductors (A-20) to (A-22) were excellent in oil crack resistance compared to the photoconductor (A-23).

  The electrophotographic photoreceptor according to the present invention can be applied to an image forming apparatus such as a multifunction peripheral.

DESCRIPTION OF SYMBOLS 10 Multilayer type electrophotographic photoreceptor 11 Conductive substrate 12 Photosensitive layer 13 Charge generation layer 14 Charge transport layer 15 Intermediate layer

Claims (8)

A laminated electrophotographic photosensitive member provided with a photosensitive layer,
The photosensitive layer includes a charge generation layer containing a charge generation agent, and a charge transport layer containing an electron transport agent, a binder resin, and silica particles,
The charge transport layer is a single layer, the charge transport layer is disposed as an outermost layer,
The electron transfer agent includes a compound represented by the general formula (1), (2) or (3),
The average primary particle size of the silica particles is 50 nm or more and 150 nm or less,
The content of the silica particles is 0.5 to 15 parts by mass with respect to 100 parts by mass of the binder resin.

In the general formula (1),
R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ are each independently a hydrogen atom, an alkoxy group having 1 to 8 carbon atoms, a phenyl group, or a substituted group. Or an alkyl group having 1 to 8 carbon atoms.

In the general formula (2),
R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ , and R ₁₈ are each independently a hydrogen atom, an alkoxy group having 1 to 8 carbon atoms, a phenyl group, or a substituted group. Represents an alkyl group having 1 to 8 carbon atoms.

In the general formula (3),
R ₂₁ and R ₂₂ each independently represent a hydrogen atom, an alkoxy group having 1 to 8 carbon atoms, a phenyl group, or an optionally substituted alkyl group having 1 to 8 carbon atoms.
In the general formula (1),
R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
In the general formula (2),
R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ , and R ₁₈ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
In the general formula (3),
2. The multilayer electrophotographic photosensitive member according to claim 1, wherein R ₂₁ and R ₂₂ each independently represents an alkyl group having 1 to 5 carbon atoms.
The multilayer electrophotographic photoreceptor according to claim 1 or 2, wherein the surface of the silica particles is treated with hexamethyldisilazane.
The multilayer electrophotographic photosensitive member according to claim 1, wherein the charge transport layer further contains a phthalocyanine pigment.
The phthalocyanine pigment is a titanyl phthalocyanine having a main peak at a Bragg angle 2θ ± 0.2 ° = 28.6 ° or a Bragg angle 2θ ± 0.2 ° = 27.2 ° in a CuKα characteristic X-ray diffraction spectrum. The multilayer electrophotographic photosensitive member according to claim 4, which is a titanyl phthalocyanine or metal-free phthalocyanine having a peak.
The said electric charge transport layer further contains the compound represented by General formula (4), (5), (6) or (7) as a positive hole transport agent. Multilayer electrophotographic photoreceptor.

In the general formula (4),
Q ₁ represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a phenyl group that may be substituted with an alkyl group having 1 to 8 carbon atoms. ,
Q ₂ each independently represents an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a phenyl group,
Q ₃ , Q ₄ , Q ₅ , Q ₆ and Q ₇ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a phenyl group. And two adjacent ones of Q ₃ , Q ₄ , Q ₅ , Q ₆ , and Q ₇ may be bonded to each other to form a ring,
a represents an integer of 0 to 5, and when a represents an integer of 2 to 5, a plurality of Q ₂ bonded to the same phenyl group may be the same as or different from each other.

In the general formula (5),
Q ₈ , Q ₁₀ , Q ₁₁ , Q ₁₂ , Q ₁₃ and Q ₁₄ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or Represents a phenyl group,
Q ₉ and Q ₁₅ each independently represents an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a phenyl group,
b represents an integer of 0 to 5, and when b represents an integer of 2 to 5, a plurality of Q ₉ bonded to the same phenyl group may be the same or different from each other;
c represents an integer of 0 or more and 4 or less, and when c represents an integer of 2 or more and 4 or less, a plurality of Q ₁₅ bonded to the same phenyl group may be the same or different from each other;
k represents 0 or 1.

In the general formula (6), R _a , R _b and R _c each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a phenyl group, or an alkoxy group having 1 to 8 carbon atoms. Represents
q represents an integer of 0 or more and 4 or less, and when q represents an integer of 2 or more and 4 or less, a plurality of R _c bonded to the same phenyl group may be the same or different from each other;
m and n each independently represent an integer of 0 to 5, and when m represents an integer of 2 to 5, a plurality of R _b bonded to the same phenyl group may be the same or different from each other. In the case where n represents an integer of 2 or more and 5 or less, a plurality of R _a bonded to the same phenyl group may be the same or different from each other.

In the general formula (7),
Ar ₁ is an aryl group which may be substituted with one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a phenoxy group, and an alkoxy group having 1 to 6 carbon atoms; Or a heterocyclic group which may be substituted with one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a phenoxy group, and an alkoxy group having 1 to 6 carbon atoms,
Ar ₂ represents an aryl group which may be substituted with one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a phenoxy group, and an alkoxy group having 1 to 6 carbon atoms. Represent.
In the general formula (4),
Q ₁ represents a hydrogen atom or a phenyl group substituted with an alkyl group having 1 to 8 carbon atoms,
Q ₂ represents an alkyl group having 1 to 8 carbon atoms,
_{Q 3, Q 4, Q 5} , Q 6 and Q ₇ each independently represent a hydrogen atom, 1 to 8 of the alkyl group carbon atoms, or a carbon atom number of 1 to 8 alkoxy group, Q ₃ , Q ₄ , Q ₅ , Q ₆ and Q ₇ may be bonded to each other to form a ring,
a represents 0 or 1,
In the general formula (5),
Q ₈ , Q ₁₀ , Q ₁₁ , Q ₁₂ , Q ₁₃ and Q ₁₄ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group,
b and c represent 0;
In the general formula (6),
R _a and R _b each independently represents an alkyl group having 1 to 8 carbon atoms,
m and n each independently represent an integer of 0 or more and 2 or less,
q represents 0;
In the general formula (7),
Ar ₁ represents a phenyl group substituted with an alkyl group having 1 to 4 carbon atoms,
The multilayer electrophotographic photosensitive member according to claim 6, wherein Ar ₂ represents a phenyl group.
  The laminated electrophotographic photosensitive member according to any one of claims 1 to 7, wherein the binder resin has a viscosity average molecular weight of 40,000 or more.

Images