WO2018100813A1 - Electrophotographic photoreceptor - Google Patents

Abstract

An electrographic photoreceptor (1), provided with an electroconductive base (2) and a photosensitive layer (3). The photosensitive layer is provided with a charge generation layer (3a) and a charge transportation layer (3b). The charge generation layer contains a charge-generating agent. The charge transportation layer contains a hole transportation agent, a binder resin, and a phthalocyanine-type pigment. The binder resin contains a polyarylate resin. The polyarylate resin is represented by general formula (1). The amount of the phthalocyanine-type pigment contained is 0.01-1.00 mass parts, relative to 100 mass parts of the binder resin. In general formula (1), kt represents 2 or 3. X represents a divalent group represented by chemical formula (2A), chemical formula (2B), chemical formula (2C), or chemical formula (2D).

Description

Electrophotographic photoreceptor

The present invention relates to an electrophotographic photoreceptor.

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

Patent Document 1 describes an electrophotographic photoreceptor containing a polyarylate resin. The polyarylate resin has a repeating unit represented by the chemical formula (RA).

Japanese Patent Laid-Open No. 10-288845

However, the electrophotographic photosensitive member described in Patent Document 1 has insufficient wear resistance.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrophotographic photosensitive member provided with a photosensitive layer having excellent wear resistance.

The electrophotographic photoreceptor of the present invention comprises a conductive substrate and a photosensitive layer. The photosensitive layer includes a charge generation layer and a charge transport layer. The charge generation layer includes a charge generation agent. The charge transport layer includes a hole transport agent, a binder resin, and a phthalocyanine pigment. The binder resin includes a polyarylate resin. The polyarylate resin is represented by the general formula (1). The content of the phthalocyanine pigment is 0.01 parts by mass or more and 1.00 parts by mass or less with respect to 100 parts by mass of the binder resin.

In the general formula (1), kt represents 2 or 3. X represents a divalent group represented by the chemical formula (2A), the chemical formula (2B), the chemical formula (2C), or the chemical formula (2D).

The electrophotographic photoreceptor of the present invention is excellent in wear resistance.

It is a fragmentary sectional view showing the structure of the electrophotographic photosensitive member according to the first embodiment of the present invention. It is a fragmentary sectional view showing the structure of the electrophotographic photosensitive member according to the first embodiment of the present invention. It is a fragmentary sectional view showing the structure of the electrophotographic photosensitive member according to the first embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail, but 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. In the present specification, a compound and its derivatives may be generically named by adding “system” after the compound name. When the name of a polymer is expressed by adding “system” after the compound name, it means that the repeating unit of the polymer is derived from the compound or a derivative thereof. Further, “OEt” in the chemical formula and the general formula represents an ethoxy group.

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 alkyl group having 1 to 3 carbon atoms, and 1 carbon atom An alkoxy group having 8 or less carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cycloalkane having 5 to 7 carbon atoms, an aryl group having 6 to 14 carbon atoms , An aryloxy group having 6 to 14 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and a halogen atom have the following meanings.

An alkyl group having 1 to 8 carbon atoms is linear or branched and 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.

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

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

An alkyl group having 1 to 3 carbon atoms is linear or branched and unsubstituted. Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, a propyl group, and an isopropyl group.

An alkoxy group having 1 to 8 carbon atoms is linear or branched and 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 thereof include a pentyloxy group, a neopentyloxy group, a hexyloxy group, a heptyloxy group, and an octyloxy group.

An alkoxy group having 1 to 6 carbon atoms is linear or branched and 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.

An alkoxy group having 1 to 4 carbon atoms is linear or branched and unsubstituted. Examples of the alkoxy group having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an s-butoxy group, and a t-butoxy group.

A cycloalkane having 5 to 7 carbon atoms is unsubstituted. Examples of the cycloalkane having 5 to 7 carbon atoms include cyclopentane, cyclohexane, and cycloheptane.

An aryl group having 6 to 14 carbon atoms is unsubstituted. 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 carbon 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.

An aryloxy group having 6 to 14 carbon atoms is unsubstituted. An aryloxy group having 6 to 14 carbon atoms is a group in which an oxygen atom is bonded to an aryl group having 6 to 14 carbon atoms. Examples of the aryloxy group having 6 to 14 carbon atoms include a phenoxy group, a naphthyloxy group, an anthryloxy group, and a phenanthryloxy group.

An aralkyl group having 7 to 20 carbon atoms is unsubstituted. The aralkyl group having 7 to 20 carbon atoms is a group in which an aryl group having 6 to 14 carbon atoms and an alkyl group having 1 to 6 carbon atoms are bonded. Examples of the aralkyl group having 7 to 20 carbon atoms include phenylmethyl group (benzyl group), 2-phenylethyl group (phenethyl group), 1-phenylethyl group, 3-phenylpropyl group, and 4-phenylbutyl. Groups.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

<Electrophotographic photoreceptor>
The structure of an electrophotographic photoreceptor (hereinafter sometimes referred to as a photoreceptor) according to an embodiment of the present invention will be described. The photoreceptor according to the exemplary embodiment is a multilayer electrophotographic photoreceptor (hereinafter sometimes referred to as a multilayer photoreceptor). 1A to 1C are partial cross-sectional views showing the structure of the multilayer photoreceptor 1 according to this embodiment. As shown in FIG. 1A, the multilayer photoreceptor 1 includes a conductive substrate 2 and a photosensitive layer 3. The photosensitive layer 3 includes a charge generation layer 3a and a charge transport layer 3b. As shown in FIG. 1A, the multilayer photoreceptor 1 may include a charge generation layer 3a on a conductive substrate 2, and a charge transport layer 3b on the charge generation layer 3a. As shown in FIG. 1B, the multilayer photoreceptor 1 may include a charge transport layer 3b on the conductive substrate 2, and further include a charge generation layer 3a on the charge transport layer 3b. As shown in FIG. 1A, the charge transport layer 3 b may be disposed as the outermost surface layer of the multilayer photoreceptor 1. The charge transport layer 3b may be a single layer (single layer).

As shown in FIG. 1A, the photosensitive layer 3 may be disposed directly on the conductive substrate 2. As shown in FIG. 1C, the multilayer photoreceptor 1 includes, for example, a conductive substrate 2, an intermediate layer 4 (undercoat layer), and a photosensitive layer 3. As shown in FIG. 1C, the photosensitive layer 3 may be indirectly disposed on the conductive substrate 2. As shown in FIG. 1C, the intermediate layer 4 may be provided between the conductive substrate 2 and the charge generation layer 3a. The intermediate layer 4 may be provided, for example, between the charge generation layer 3a and the charge transport layer 3b. The charge generation layer 3a may be a single layer or a plurality of layers.

Specifically, the thickness of the charge generation layer 3a 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. The thickness of the charge transport layer 3b is not particularly limited as long as it can sufficiently function as the charge transport layer 3b. Specifically, the thickness of the charge transport layer 3b is preferably 2 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.

Hereinafter, the elements (conductive substrate 2, photosensitive layer 3, and intermediate layer 4) of the multilayer photoreceptor 1 according to the present embodiment will be described. Further, a method for manufacturing the photoreceptor 1 will be described.

[1. Conductive substrate]
The conductive substrate 2 is not particularly limited as long as it can be used as the conductive substrate of the photoreceptor 1. As the conductive substrate 2, a conductive substrate composed of a material having at least a surface portion having conductivity (hereinafter sometimes referred to as a conductive material) can be used. An example of the conductive substrate 2 is a conductive substrate made of a conductive material. Another example of the conductive substrate 2 is a conductive substrate coated with a conductive material. Examples of the conductive material include aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, and indium. These conductive materials may be used alone or in combination of two or more. Examples of the combination of two or more include alloys (more specifically, aluminum alloy, stainless steel, brass, etc.). Of these conductive materials, aluminum or an aluminum alloy is preferable.

The shape of the conductive substrate 2 can be appropriately selected according to the structure of the image forming apparatus to be used. Examples of the shape of the conductive substrate 2 include a sheet shape and a drum shape. Further, the thickness of the conductive substrate 2 can be appropriately selected according to the shape of the conductive substrate 2.

[2. Photosensitive layer]
The charge generation layer 3a contains a charge generation agent. The charge generation layer 3a may contain a charge generation layer binder resin (hereinafter sometimes referred to as a base resin). The charge transport layer 3b includes a hole transport agent, a binder resin, and a phthalocyanine pigment. The charge generation layer 3a and the charge transport layer 3b may contain an additive. Hereinafter, the charge generator, the phthalocyanine pigment, the hole transport agent, the binder resin, the base resin, and the additive will be described.

[2-1. Charge generator, phthalocyanine pigment]
The charge generator is not particularly limited as long as it is a charge generator for the photoreceptor 1. 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, and cyanine pigments. Powders of inorganic photoconductive materials such as selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, amorphous silicon, pyrylium salts, ansanthrone pigments, triphenylmethane pigments, selenium pigments, toluidine pigments, pyrazoline pigments Examples thereof include pigments and quinacridone pigments. Examples of the phthalocyanine pigment include phthalocyanine pigments and phthalocyanine derivative pigments. Examples of the phthalocyanine pigment include a metal-free phthalocyanine pigment (more specifically, an X-type metal-free phthalocyanine pigment (xH ₂ Pc) and the like). Examples of the phthalocyanine derivative pigment include metal phthalocyanine pigments (more specifically, titanyl phthalocyanine pigments, copper phthalocyanine pigments, V-type hydroxygallium phthalocyanine pigments, and the like). 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, ε-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. Of these charge generators, phthalocyanine pigments are preferable, and Y-type titanyl phthalocyanine pigments are more preferable.

A charge generator having an absorption wavelength in a desired region may be used alone, or two or more charge generators may be used in combination. Further, for example, in a digital optical image forming apparatus, it is preferable to use a photoconductor having sensitivity in a wavelength region of 700 nm or more. Examples of the digital optical image forming apparatus include a laser beam printer or a facsimile using a light source such as a semiconductor laser. Therefore, for example, phthalocyanine pigments are preferable, and X-type metal-free phthalocyanine pigments or Y-type titanyl phthalocyanine pigments are more preferable.

For a photoreceptor applied to an image forming apparatus using a short wavelength laser light source, an ansanthrone pigment or a perylene pigment is preferably used as a charge generating agent. Examples of the wavelength of the short wavelength laser include wavelengths of 350 nm or more and 550 nm or less.

The charge generators are, for example, phthalocyanine pigments represented by chemical formulas (CGM-1) to (CGM-4) (hereinafter referred to as charge generators (CGM-1) to (CGM-4), respectively). There).

The content of the charge generation agent in the charge generation layer 3a is preferably 0.1 parts by weight or more and 50 parts by weight or less, and 0.5 parts by weight or more and 30 parts by weight or less with respect to 100 parts by weight of the charge generation layer binder resin. The amount is more preferably 0.5 parts by mass or less, and particularly preferably 0.5 parts by mass or more and 4.5 parts by mass or less.

Examples of the phthalocyanine pigment in the charge transport layer 3b include a metal-free phthalocyanine pigment or a metal phthalocyanine pigment. Examples of the metal-free phthalocyanine pigment include X-type metal-free phthalocyanine pigment. Examples of metal phthalocyanine pigments include titanyl phthalocyanine pigments (more specifically, Y-type titanyl phthalocyanine pigments or α-type titanyl phthalocyanine pigments) or copper phthalocyanine pigments (more specifically, ε-type copper phthalocyanine pigments). Can be mentioned. Examples of the phthalocyanine pigment in the charge transport layer 3b include an X-type metal-free phthalocyanine pigment, a Y-type titanyl phthalocyanine pigment, an α-type titanyl phthalocyanine pigment, or an ε-type copper phthalocyanine pigment.

The content of the phthalocyanine pigment in the charge transport layer 3b is 0.01 parts by mass or more and 1.00 parts by mass or less with respect to 100 parts by mass of the binder resin. When the content of the phthalocyanine pigment in the charge transport layer 3b exceeds 1.00 parts by mass with respect to 100 parts by mass of the binder resin, the sensitivity repeatability in a high temperature and high humidity environment decreases. This is because the absorption of exposure light in the charge transport layer 3b is increased, making it difficult for the exposure light to reach the charge generation layer 3a, and sufficient carriers are not generated. If the content of the phthalocyanine pigment in the charge transport layer 3b is less than 0.01 parts by mass with respect to 100 parts by mass of the binder resin, the sensitivity repeatability in a high temperature and high humidity environment is deteriorated. This is because residual charges in the photosensitive layer 3 accumulate and carriers are less likely to reach the surface of the photoreceptor 1.

[2-2. Hole transport agent]
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 diamine derivatives (more specifically, benzidine derivatives, N, N, N ′, N′-tetraphenylphenylenediamine derivatives, N, N, N ′). , N′-tetraphenylnaphthylenediamine derivative, or N, N, N ′, N′-tetraphenylphenanthrylenediamine derivative, etc.); oxadiazole compounds (more specifically, 2,5-di ( 4-methylaminophenyl) -1,3,4-oxadiazole, etc.); styryl compounds (more specifically, 9- (4-diethylaminostyryl) anthracene, etc.); carbazole compounds (more specifically, Organic polysilane compounds; pyrazoline compounds (more specifically, 1-phenyl-3- (p-dimethylaminophenyl) pi Ethylbenzthiazoline etc.); hydrazone compounds; indole-based compound; oxazole-based compounds; isoxazole compounds; thiazole compounds; thiadiazole compounds; imidazole compounds; pyrazole compound; triazole compounds.

Among these hole transporting agents, compounds represented by the general formula (2), the general formula (3), the general formula (4), the general formula (5), or the general formula (6) (hereinafter each referred to as a hole). Transport agents (2), (3), (4), (5), and (6) may be described) are preferred. That is, the hole transport agent preferably contains a hole transport agent (2), (3), (4), (5), or (6). The charge transport layer contains the hole transport agent (2), (3), (4), (5) or (6), thereby improving the repetitive characteristics of the sensitivity of the photoreceptor in a high temperature and high humidity environment. It is also possible to improve the potential environment stability and wear resistance of the photoreceptor. From the viewpoint of further improving the potential environment stability of the photoreceptor, the hole transport agent is preferably the hole transport agent (2), (3), (4) or (5). 3), (4), or (5) is more preferable, and the hole transport agent (3) is still more preferable. From the viewpoint of further improving the abrasion resistance of the photoreceptor, the hole transport agent is preferably the hole transport agent (4), (5), or (6), more preferably the hole transport agent (4). preferable.

In general formula (2), 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. The phenyl group 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. To express. 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 General Formula (3), 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 phenylene group may be the same as or different from each other. k represents 0 or 1.

In general formula (4), R _a , R _b and R _c each independently represents an alkyl group having 1 to 8 carbon atoms, a phenyl group, or an alkoxy group having 1 to 8 carbon atoms. q 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 phenylene group may be the same as 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 (5), R ¹ , R ² , and R ³ are each independently an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and 6 to 14 carbon atoms. The following aryl groups, aryloxy groups having 6 to 14 carbon atoms, aralkyl groups having 7 to 20 carbon atoms, halogen atoms, or hydrogen atoms are represented. R ² and R ³ may be bonded to each other. d represents 1 or 2.

In general formula (6), R ¹¹¹ and R ¹¹² are each independently an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms. Represents an aryloxy group having 6 to 14 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or a halogen atom. d ₁ and d ₂ each independently represents an integer of 0 or more and 5 or less. d ₃ represents 1 or 2.

In general formula (2), 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 (2), 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 (2), 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 preferably an n-butyl group. More preferred. In general formula (2), the alkoxy group having 1 to 8 carbon atoms represented by Q ₃ to Q ₇ is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group or an ethoxy group. . In general formula (2), 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, More preferably, it represents an atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms.

In the general formula (2), 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, adjacent Q ₆ and Q _{7 of} 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 general formula (2), Q ₁ represents a phenyl group or a hydrogen atom, the phenyl group is substituted with an alkyl group having 1 to 8 carbon atoms, and Q ₂ has 1 to 8 carbon atoms. Q ₃ to Q ₇ each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms, and a is 0 or 1 Is preferably represented. Two adjacent Q ₃ to Q ₇ may be bonded to each other to form a ring.

In general formula (3), 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 more preferable that In general formula (3), Q ₈ and Q ₁₀ to Q ₁₄ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group, and b and c each represent 0. Is preferred.

In general formula (4), the alkyl group having 1 to 8 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. In General Formula (4), R _a and R _b represent an alkyl group having 1 to 8 carbon atoms, m and n each independently represent an integer of 0 to 2, and q represents 0. It is preferable.

In general formula (5), the aryl group having 6 to 14 carbon atoms represented by R ¹ , R ² and R ³ is preferably a phenyl group.

In general formula (5), R ² and R ³ may be bonded to each other. As a result of bonding to each other, a ring may be formed. Examples of such a ring include a cycloalkane (more specifically, a cycloalkane having 5 to 7 carbon atoms) or an aromatic ring (more specifically, an aromatic ring having 5 to 7 carbon atoms). Is mentioned. For example, when both R ² and R ³ represent a phenyl group, R ² and R ³ may be bonded to each other to form a ring and become a fluorenyl group.

R ¹ , R ² , and R ³ each preferably represents an aryl group having 6 to 14 carbon atoms. R ² and R ³ may be bonded to each other.

In general formula (6), R ¹¹¹ and R ¹¹² each preferably represents an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, More preferably, it represents a group.

When d ₁ represents an integer of 2 or more and 5 or less, the plurality of R ¹¹¹ may be the same as or different from each other. The bonding position of R ¹¹¹ is not particularly limited. R ¹¹¹ may be bonded to the ortho, meta, or para position of the phenyl group, and is preferably bonded to the para position of the phenyl group. When d ₂ represents an integer of 2 or more and 5 or less, the plurality of R ¹¹² may be the same as or different from each other. The bonding position of R ¹¹² is not particularly limited. R ¹¹² may be bonded to the ortho, meta, or para position of the phenyl group, and is preferably bonded to the para position of the phenyl group. In the general formula (6), d ₁ and d ₂ are each independently preferably represents 0 or 1.

In general formula (6), d ₃ represents 1 or 2. When d ₃ represents 1, the general formula (6) corresponds to the general formula (6-1). When d ₃ represents 2, the general formula (6) corresponds to the general formula (6-2). R ¹¹¹ in formula (6-1) and (6-2) in, R ^112, d ₁ and d ₂ are each, R ¹¹¹ in formula (6) in, R ^112, d ₁ and d ₂ as defined It is. D ₃ in the general formula (6) preferably represents 1.

In the general formula (6), R ¹¹¹ and R ¹¹² each represents an alkyl group having 1 to 6 carbon atoms, d ₁ and d ₂ each independently represent 0 or 1, and d ₃ is 1 is preferably represented.

Examples of the hole transport agent (2) include hole transport agents represented by chemical formulas (HTM-1) to (HTM-4) (hereinafter referred to as hole transport agents (HTM-1) to (HTM-4, respectively). ) May be described. Examples of the hole transporting agent (3) include hole transporting agents represented by chemical formulas (HTM-5) and (HTM-7) (hereinafter referred to as hole transporting agent (HTM-5) and (HTM-7, respectively). ) May be described. Examples of the hole transporting agent (4) include hole transporting agents represented by chemical formulas (HTM-6) and (HTM-8) (hereinafter referred to as hole transporting agent (HTM-6) and (HTM-8), respectively). ) May be described. Examples of the hole transporting agent (5) include hole transporting agents represented by chemical formula (HTM-11) and chemical formula (HTM-12) (hereinafter referred to as hole transporting agent (HTM-11) and (HTM- 12))). Examples of the hole transporting agent (6) include hole transporting agents represented by chemical formula (HTM-9) and chemical formula (HTM-10) (hereinafter referred to as hole transporting agent (HTM-9) and (HTM- 10))).

Each of the hole transport agents (2) to (5) can be produced, for example, by appropriately applying a known method. The hole transport agent (6) can be produced, for example, by the following method. The hole transporting agent (6) is, for example, a reaction represented by the reaction formulas (r-1), (r-2) and (r-3) (hereinafter referred to as reactions (r-1) and (r-2), respectively. ) And (r-3)), or according to a similar method. Reaction (r-1), (r -2) and ^{(r-3) R 111,} R 112, d 1, d 2 in, and d ₃ are each formula in (6) R ^111, R ¹¹² , d ₁ , d ₂ , and d ₃ are synonymous.

In the reaction (r-1), 1 mol equivalent of the compound represented by the chemical formula (A1) (hereinafter referred to as the compound (A1)) and 1 mol equivalent of triethyl phosphite are reacted to give 1 mol An equivalent amount of the compound represented by the chemical formula (B1) (hereinafter referred to as the compound (B1)) is obtained. In the reaction (r-1), it is preferable to add 1 mol to 2.5 mol of triethyl phosphite with respect to 1 mol of the compound (A1). The reaction temperature for reaction (r-1) is preferably 160 ° C. or higher and 200 ° C. or lower. The reaction time for reaction (r-1) is preferably 2 hours or longer and 10 hours or shorter.

In the reaction (r-2), 1 mol equivalent of a compound represented by the chemical formula (A2) (hereinafter referred to as the compound (A2)) and 1 mol equivalent of triethyl phosphite are reacted to give 1 mol An equivalent amount of the compound represented by the chemical formula (B2) (hereinafter referred to as the compound (B2)) is obtained. Reaction (r-2) can be carried out in the same manner as in reaction (r-1), except that compound (A1) is changed to compound (A2).

In the reaction (r-3), 1 molar equivalent of the compound represented by the chemical formula (C) (hereinafter referred to as the compound (C)), 1 molar equivalent of the compound (B1), and 1 molar equivalent of the compound ( B2) is reacted with to obtain 1 molar equivalent of the hole transporting agent (6). It is preferable to add 1 mol or more and 5 mol or less of compound (B1) with respect to 1 mol of compound (C). It is preferable to add 1 mol or more and 5 mol or less of compound (B2) with respect to 1 mol of compound (C). The reaction temperature for reaction (r-3) is preferably 0 ° C. or higher and 50 ° C. or lower. The reaction time for reaction (r-3) is preferably 10 minutes to 24 hours. The reaction (r-3) may be performed in an atmosphere of an inert gas (for example, argon gas).

The reaction (r-3) may be performed in the presence of a base. Examples of the base include sodium alkoxide (more specifically, sodium methoxide or sodium ethoxide), metal hydride (more specifically, sodium hydride, potassium hydride, etc.) or metal salt (more specifically, Specifically, n-butyllithium and the like can be mentioned. Of these bases, sodium methoxide is preferred. These bases may be used individually by 1 type, and may be used in combination of 2 or more type. The amount of the base added is preferably 1 mol or more and 3 mol or less with respect to 1 mol of the compound (C).

The reaction (r-3) may be performed in a solvent. Examples of the solvent include ether (more specifically, tetrahydrofuran, diethyl ether, dioxane and the like), halogenated hydrocarbon (more specifically, methylene chloride, chloroform, dichloroethane and the like) or aromatic hydrocarbon (more specifically, Specifically, benzene, toluene, etc.) are mentioned. Of these solvents, tetrahydrofuran is preferred.

By purifying the reaction product (product) obtained in the reaction (r-3) as necessary, the hole transport agent (6) as the target compound can be isolated. As a purification method, a known method is appropriately employed, and examples thereof include crystallization or silica gel chromatography. Examples of the solvent used for purification include chloroform, hexane, and a mixed solvent of chloroform and hexane.

The content of the hole transporting agent is preferably 10 parts by mass or more and 200 parts by mass or less, and more preferably 10 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the binder resin.

[2-3. Binder resin]
The binder resin includes a polyarylate resin (1). The polyarylate resin (1) is represented by the general formula (1).

In general formula (1), kt represents 2 or 3. X represents a divalent group represented by the chemical formula (2A), the chemical formula (2B), the chemical formula (2C), or the chemical formula (2D).

In general formula (1), kt represents 3, and X preferably represents a divalent group represented by chemical formula (2B), chemical formula (2C), or chemical formula (2D).

The polyarylate resin (1) is represented by a repeating unit represented by the chemical formula (1-5) (hereinafter sometimes referred to as a repeating unit (1-5)) and a general formula (1-6). Repeating units (hereinafter sometimes referred to as repeating units (1-6)).

Kt in general formula (1-5) and X in general formula (1-6) have the same meanings as kt and X in general formula (1), respectively.

The polyarylate resin (1) may have a repeating unit other than the repeating units (1-5) and (1-6). The ratio (molar fraction) of the total amount of the repeating units (1-5) and (1-6) to the total amount of the repeating units in the polyarylate resin (1) is preferably 0.80 or more, 0.90 or more is more preferable, and 1.00 is still more preferable.

The arrangement of the repeating units (1-5) and (1-6) in the polyarylate resin (1) is not particularly limited as long as the repeating unit derived from the aromatic diol and the repeating unit derived from the aromatic dicarboxylic acid are adjacent to each other. .

Examples of the polyarylate resin (1) include polyarylate resins represented by chemical formulas (R-1) to (R-4) (hereinafter referred to as polyarylate resins (R-1) to (R-4)). May be included).

The viscosity average molecular weight of the polyarylate resin (1) is preferably 10,000 or more, more preferably 20,000 or more, still more preferably 30,000 or more, and 45,000 or more. It is particularly preferred. The viscosity average molecular weight of the polyarylate resin (1) is preferably 80,000 or less, more preferably 60,000 or less, and further preferably 52,000 or less. When the viscosity average molecular weight of the polyarylate resin (1) is 10,000 or more, the wear resistance of the binder resin can be increased, and the charge transport layer 3b is hardly worn. On the other hand, when the viscosity average molecular weight of the polyarylate resin (1) is 80,000 or less, the polyarylate resin (1) is easily dissolved in the solvent during the formation of the photosensitive layer 3, and the formation of the photosensitive layer 3 is easy. Tend to be.

As the binder resin, only the polyarylate resin (1) may be used alone, or a resin (other resin) other than the polyarylate resin (1) may be included within a range that does not impair the effects of the present invention. Good. Examples of other resins include thermoplastic resins (more specifically, polyarylate resins other than polyarylate resin (1), polycarbonate resins, styrene resins, styrene-butadiene copolymers, and styrene-acrylonitrile copolymers. , Styrene-maleic acid copolymer, styrene-acrylic acid copolymer, 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, polysulfone resin, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, or polyester resin), thermosetting resin (more specific) In , Silicone resin, epoxy resin, phenol resin, urea resin, melamine resin, or other cross-linkable thermosetting resin), or photo-curing resin (more specifically, epoxy-acrylic resin or urethane) -Acrylic acid copolymer). These may be used alone or in combination of two or more.

(Production method of polyarylate resin (1))
The production method of the polyarylate resin (1) is not particularly limited as long as the polyarylate resin (1) can be produced. Examples of these production methods include a method of polycondensing an aromatic diol and an aromatic dicarboxylic acid for constituting a repeating unit of the polyarylate resin (1). The synthesis method of the polyarylate resin (1) is not particularly limited, and a known synthesis method (more specifically, solution polymerization, melt polymerization, interfacial polymerization, or the like) can be employed. Hereinafter, an example of the manufacturing method of polyarylate resin (1) is demonstrated.

The polyarylate resin (1) is produced, for example, according to the reaction represented by the reaction formula (R-1) (hereinafter sometimes referred to as reaction (R-1)) or by a method analogous thereto. The method for producing the polyarylate resin (1) includes, for example, reaction (R-1).

In reaction (R-1), kt in general formula (1-11) and X in general formula (1-9) have the same meanings as kt and X in general formula (1), respectively.

In the reaction (R-1), an aromatic dicarboxylic acid represented by the general formula (1-9) (hereinafter sometimes referred to as aromatic dicarboxylic acid (1-9)) and a general formula (1-11) ) (Hereinafter sometimes referred to as aromatic diol (1-11)) to obtain polyarylate resin (1).

The amount of the aromatic diol (1-11) relative to 1 mol of the aromatic dicarboxylic acid (1-9) is preferably 0.9 to 1.1 mol. Within the above range, the polyarylate resin (1) can be easily purified, and the yield of the polyarylate resin (1) is improved.

The reaction (R-1) may be allowed to proceed in the presence of an alkali and a catalyst. Examples of the catalyst include tertiary ammonium (more specifically, trialkylamine and the like) or quaternary ammonium salt (more specifically, benzyltrimethylammonium bromide and the like). Examples of the alkali include alkali metal hydroxides (more specifically, sodium hydroxide or potassium hydroxide) and alkaline earth metal hydroxides (more specifically, calcium hydroxide). Can be mentioned. Reaction (R-1) may be allowed to proceed in a solvent and under an inert gas atmosphere. Examples of the solvent include water or chloroform. Examples of the inert gas include argon. The reaction time for reaction (R-1) is preferably 2 hours or longer and 5 hours or shorter. The reaction temperature is preferably 5 ° C or higher and 25 ° C or lower. *

Examples of the aromatic dicarboxylic acid (1-9) include an aromatic dicarboxylic acid having two carboxyl groups bonded on the aromatic ring (more specifically, 2,6-naphthalenedicarboxylic acid, 4,4′- Dicarboxydiphenyl ether, or 4,4′-dicarboxybiphenyl). The aromatic dicarboxylic acid may contain other dicarboxylic acids in addition to the aromatic dicarboxylic acid (1-9). In the synthesis of the polyarylate resin (1), a derivative of the aromatic dicarboxylic acid (1-9) (more specifically, a halogenated alkanoyl or aromatic dicarboxylic acid, instead of the aromatic dicarboxylic acid (1-9). Acid anhydride) may be used.

Examples of the aromatic diol (1-11) include 1,1-bis (3-methylphenyl) cyclohexane or 1,1-bis (3-methylphenyl) cyclopentane. In the reaction (R-1), as the aromatic diol, in addition to the aromatic diol (1-11), another diol (for example, bisphenol A, bisphenol S, bisphenol E, or bisphenol F) may be used. In the synthesis of the polyarylate resin (1), an aromatic diol derivative can be used in place of the aromatic diol (1-11). Examples of the aromatic diol derivative include diacetate.

In the production of the polyarylate resin (1), other steps may be included as necessary. An example of such a process is a purification process. Examples of the purification method include known methods (more specifically, filtration, chromatography, crystal folding, etc.).

[2-4. Base resin]
The base resin is not particularly limited as long as it can be applied to the photoreceptor 1. Examples of the base resin include a thermoplastic resin, a thermosetting resin, and a photocurable resin. Examples of the thermoplastic resin include a styrene resin, a styrene-butadiene copolymer, a styrene-acrylonitrile copolymer, a styrene-maleic acid copolymer, a styrene-acrylic acid copolymer, an acrylic copolymer, and a polyethylene resin. , Ethylene-vinyl acetate copolymer, chlorinated polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer, vinyl chloride-vinyl acetate copolymer, alkyd resin, polyamide resin, urethane resin, polycarbonate resin, polyarylate resin, polysulfone Examples of the resin include diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, and polyester resin. Examples of the thermosetting resin include silicone resins, epoxy resins, phenol resins, urea resins, melamine resins, and other crosslinkable thermosetting resins. Examples of the photocurable resin include an epoxy acrylic resin or a urethane-acrylic resin. These may be used individually by 1 type and may be used in combination of 2 or more type.

As the base resin, the same resin as the above-described binder resin is also exemplified, but in the same laminated photoreceptor 1, a resin different from the binder resin is usually selected. This is based on the following reasons. When the multilayer photoconductor 1 is manufactured, the charge generating layer 3a and the charge transport layer 3b are usually formed in this order, and therefore a coating solution for forming a charge transport layer on the charge generation layer 3a (hereinafter referred to as charge transport layer use) (It may be described as a coating solution). When the charge transport layer 3b is formed, the charge generation layer 3a is preferably not dissolved in the solvent of the charge transport layer coating solution. Therefore, as the base resin, a resin different from the binder resin is usually selected in the same laminated photoreceptor 1.

[2-5. Additive]
Examples of the additive include a deterioration inhibitor (more specifically, an antioxidant, a radical scavenger, a quencher, or an ultraviolet absorber), a softener, a surface modifier, a bulking agent, a thickener, Examples include dispersion stabilizers, waxes, donors, surfactants, or leveling agents.

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.

[3. Middle layer]
The photoreceptor 1 according to the second embodiment may have an intermediate layer 4 (for example, an undercoat layer). The intermediate layer 4 contains, for example, inorganic particles and a resin (intermediate layer resin). By interposing the intermediate layer 4, it is possible to smooth the flow of current generated when the photosensitive member 1 is exposed and suppress an increase in electric resistance while maintaining an insulating state capable of suppressing the occurrence of current leakage. it can.

Examples of the inorganic particles include metal (more specifically, aluminum, iron, copper, etc.) particles, metal oxide (more specifically, titanium oxide, alumina, zirconium oxide, tin oxide, or zinc oxide). Etc.) or non-metal oxide (more specifically, silica etc.) particles. These inorganic particles may be used individually by 1 type, and may use 2 or more types together. The inorganic particles may be subjected to a surface treatment.

The intermediate layer resin is not particularly limited as long as it can be used as a resin for forming the intermediate layer 4.

[4. Photoconductor manufacturing method]
In the method for manufacturing the multilayer photoreceptor 1, the photosensitive layer forming step includes a charge generation layer forming step and a charge transport layer forming step. In the charge generation layer forming step, first, a coating solution for forming the charge generation layer 3a (hereinafter, sometimes referred to as a charge generation layer coating solution) is prepared. The charge generation layer coating solution is applied onto the conductive substrate 2 to form a coating film. Next, the coating film is dried by an appropriate method to remove at least a part of the solvent contained in the coating film to form the charge generation layer 3a. 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 may be added to the charge generation layer coating solution as necessary.

In the charge transport layer forming step, first, a charge transport layer coating solution is prepared. The charge transport layer coating solution is applied onto the charge generation layer 3a to form a coating film. Next, the coating film is dried by an appropriate method to remove at least a part of the solvent contained in the coating film, thereby forming the charge transport layer 3b. The coating solution for charge transport layer contains a hole transport agent, a polyarylate resin (1) as a binder resin, a phthalocyanine pigment, and a solvent. The coating solution for the charge transport layer can be prepared by dissolving or dispersing the hole transport agent, the polyarylate resin (1), and the phthalocyanine pigment in a solvent. Various additives may be added to the charge transport layer coating solution as necessary.

Hereinafter, 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 (hereinafter, these two coating solutions may be referred to as coating solutions) can dissolve or disperse each component contained in the coating solution. And if it is easy to remove from a coating film by drying, it will not specifically limit. Examples of the solvent include alcohol (more specifically, methanol, ethanol, isopropanol, butanol, etc.), aliphatic hydrocarbon (more specifically, n-hexane, octane, cyclohexane, etc.), aromatic carbonization, and the like. Hydrogen (more specifically, benzene, toluene, xylene, etc.), halogenated hydrocarbon (more specifically, dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene, etc.), ether (more specifically, dimethyl ether) , Diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, or diethylene glycol dimethyl ether), ketones (more specifically, acetone, methyl ethyl ketone, or cyclohexanone), esters (more specifically, ethyl acetate or methyl acetate, etc.), Methyl formaldehyde, 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. Examples of the combination of two or more include a mixed solvent containing methanol, butanol and toluene, a mixed solvent containing propylene glycol monomethyl ether and tetrahydrofuran, or a mixed solvent containing tetrahydrofuran and toluene.

Coating solution is prepared by mixing each component and dispersing 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 coating liquid may contain, for example, a surfactant or a leveling agent in order to improve the dispersibility of each component or the surface smoothness of each layer formed.

The method for applying the coating solution is not particularly limited as long as it is a method capable of uniformly applying the coating solution. Examples of the coating method include a dip coating method, a spray coating method, a spin coating method, and a bar coating method.

The method for removing at least a part of the solvent contained in the coating solution is not particularly limited as long as it is a method capable of evaporating the solvent in the coating solution. Examples of the removal method include heating, reduced pressure, or combined use of heating and reduced pressure. More specifically, a method of performing heat treatment (hot air drying) using a high-temperature dryer or a vacuum dryer can be mentioned. The heat treatment conditions are, for example, a temperature of 40 ° C. or higher and 150 ° C. or lower and a time of 3 minutes or longer and 120 minutes or shorter.

Note that the method for manufacturing the photoreceptor 1 may further include a step of forming the intermediate layer 4 as necessary. A known method can be appropriately selected for the step of forming the intermediate layer 4.

Since the electrophotographic photoreceptor of the present invention described above is excellent in fog resistance, it can be suitably used in various image forming apparatuses.

Hereinafter, the present invention will be described more specifically using examples. The present invention is not limited to the scope of the examples.

The following charge generators, hole transport agents, binder resins, and pigments were prepared as materials for producing a laminated photoreceptor.

(Charge generator)
The charge generating agent (CGM-2) described in the second embodiment was prepared. The charge generating agent (CGM-2) was a titanyl phthalocyanine pigment (Y-type titanyl phthalocyanine pigment, Y-type titanyl phthalocyanine crystal) represented by the chemical formula (CGM-2). The crystal structure was Y-type.

Y-type titanyl phthalocyanine crystal has a Bragg angle of 2θ ± 0.2 ° = 9.2 °, 14.5 °, 18.1 °, 24.1 °, 27.2 ° in the CuKα characteristic X-ray diffraction spectrum chart. It had a peak, and the main peak was 27.2 °. The CuKα characteristic X-ray diffraction spectrum was measured using the measurement apparatus and measurement conditions described in the second embodiment.

(Hole transport agent)
The hole transport agents (HTM-1) to (HTM-12) described in the second embodiment were prepared.

(Binder resin)
In addition to the polyarylate resins (R-1) to (R-4) described in the first embodiment, binder resins (R-5) to (R-6) were prepared. Binder resins (R-5) to (R-6) are polyarylate resins having repeating units represented by chemical formulas (R-5) to (R-6), respectively.

(Method for synthesizing polyarylate resins (R-1) to (R-4))
A method for synthesizing the polyarylate resins (R-1) to (R-4) will be described below.

[Preparation of polyarylate resin (R-1)]
A three-necked flask was used as a reaction vessel. This reaction container is a 1 L three-necked flask equipped with a thermometer, a three-way cock, and a dropping funnel 200 mL. In a reaction vessel, 12.1-g (41.3 mmol) of 1,1-bis (3-methyl-4-hydroxyphenyl) cyclohexane, 0.06 g (0.41 mmol) of t-butylphenol, and 3.9 g of sodium hydroxide (98 mmol) and 0.12 g (0.38 mmol) of benzyltributylammonium chloride were added. Next, the inside of the reaction vessel was purged with argon. Thereafter, 600 mL of water was further added to the reaction vessel. The contents of the reaction vessel were stirred for 1 hour under the condition of the internal temperature of the reaction vessel of 20 ° C. Next, the contents of the reaction vessel were cooled, and the internal temperature of the reaction vessel was lowered to 10 ° C. In this way, an alkaline aqueous solution was prepared.

9.56 g (32.4 mmol) of 4,4'-oxybisbenzoic acid chloride was dissolved in 300 g of chloroform to separately prepare a chloroform solution.

Subsequently, the internal temperature of the reaction container of the alkaline aqueous solution was maintained at 10 ° C., and the contents in the reaction container were stirred. The chloroform solution was put into an aqueous alkali solution to initiate the polymerization reaction. The polymerization reaction was allowed to proceed for 3 hours while stirring the contents of the reaction vessel and maintaining the internal temperature in the reaction vessel at 13 ± 3 ° C. Thereafter, the upper layer (aqueous layer) was removed using a decant to obtain an organic layer.

A 2 L Erlenmeyer flask was used as a reaction vessel. After adding 500 mL of ion-exchanged water to the reaction vessel, the organic layer was added. Further, 300 g of chloroform and 6 mL of acetic acid were added to the reaction vessel. The contents of the reaction vessel were stirred at room temperature (25 ° C.) for 30 minutes. Next, the upper layer (aqueous layer) was removed by decanting to obtain an organic layer. Next, the organic layer was washed 8 times with a separatory funnel using 500 mL of ion-exchanged water.

The organic layer after washing with water was taken out by liquid separation. The organic layer was filtered to obtain a filtrate. 1.5 L of methanol was put into a 3 L beaker. While methanol was stirred, the organic layer was slowly added dropwise to obtain a precipitate. The precipitate was filtered off. The obtained precipitate was vacuum-dried at a temperature of 70 ° C. for 12 hours. As a result, polyarylate resin (R-1) was obtained. The yield of the polyarylate resin (R-1) was 10.1 g, and the yield was 58.3 mol%.

[Preparation of polyarylate resins (R-2) to (R-4)]
The same procedure as for the polyarylate resin (R-1) except that 4,4′-oxybisbenzoyl chloride was changed to the halogenated alkanoyl starting material of the polyarylate resins (R-2) to (R-4). Polyarylate resins (R-2) to (R-4) were produced respectively. The amount of halogenated alkanoyl was the same as the amount of halogenated alkanoyl in the synthesis of polyarylate resins (R-1) to (R-4).

(Pigment)
As the pigment, the X-type metal-free phthalocyanine pigment, the Y-type titanyl phthalocyanine pigment, the α-type titanyl phthalocyanine pigment, and the ε-type copper phthalocyanine pigment described in the second embodiment were prepared.

<Manufacture of photoconductor>
[Photoreceptor (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 with alumina and silica, and further, surface-treated with methyl hydrogen polysiloxane was prepared while wet-dispersing the surface-treated titanium oxide. Subsequently, surface-treated titanium oxide (2 parts by mass) and Amilan (registered trademark) (“CM8000” manufactured by Toray Industries, Inc.) (1 part by mass) as a polyamide resin were added to the mixed solvent. Amilan was a quaternary copolymerized polyamide resin of polyamide 6, polyamide 12, polyamide 66, and polyamide 610. This mixed solvent was a solvent containing methanol (10 parts by mass), butanol (1 part by mass), and toluene (1 part by mass). These were mixed for 5 hours using a bead mill, and materials (surface-treated titanium oxide and polyamide resin) were dispersed in a mixed solvent. This prepared the coating liquid for intermediate | middle layers.

The obtained intermediate layer coating solution was filtered using a filter having an opening of 5 μm. Then, the coating liquid for intermediate | middle layers was apply | coated to the surface of the drum-shaped support body (diameter 30mm, full length 246mm) as an electroconductive base | substrate using the dip coating method, and the coating film was formed. Subsequently, the coating film was dried at 130 ° C. for 30 minutes to form an intermediate layer (film thickness: 1.5 μm) on the conductive substrate (drum-shaped support).

(Formation of charge generation layer)
A Y-type titanyl phthalocyanine pigment (1.5 parts by mass) and a polyvinyl acetal resin (“SREC BX-5” manufactured by Sekisui Chemical Co., Ltd.) (1 part by mass) as a base resin were added to a mixed solvent. This mixed solvent was a solvent containing propylene glycol monomethyl ether (40 parts by mass) and tetrahydrofuran (40 parts by mass). These were mixed for 12 hours using a bead mill, and materials (Y-type titanyl phthalocyanine pigment and polyvinyl acetal resin) were dispersed in a mixed solvent to prepare a charge generation layer coating solution. The obtained coating solution for charge generation layer was filtered using a filter having an opening of 3 μm. Subsequently, the obtained filtrate was applied onto the intermediate layer formed as described above by using a dip coating method to form a coating film. Subsequently, the coating film 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)
50 parts by mass of a hole transporting agent (HTM-1), 2 parts by mass of a hindered phenol antioxidant (“Irganox (registered trademark) 1010” manufactured by BASF Corporation) as an additive, and 3 as an electron acceptor compound , 3 ′, 5,5′-tetra-tert-butyl-4,4′-diphenoquinone, 0.04 parts by mass of an X-type metal-free phthalocyanine pigment as a phthalocyanine pigment, and a polyarylate resin as a binder resin ( R-1) 100 parts by mass was added to the mixed solvent. This mixed solvent was a solvent containing 550 parts by mass of tetrahydrofuran and 150 parts by mass of toluene. These were mixed for 12 hours, and the materials (hole transport agent (HTM-1), hindered phenol antioxidant, electron acceptor compound, X-type metal-free phthalocyanine pigment, and polyarylate resin (R-1) were mixed in a mixed solvent. ) Was dispersed to prepare a coating solution for charge transport layer.

The charge transport layer coating solution was applied onto the charge generation layer by the same operation as the charge generation layer coating solution to form a coating film. Thereafter, the coating film was dried at 120 ° C. for 40 minutes to form a charge transport layer (film thickness 20 μm) on the charge generation layer. As a result, a photoreceptor (A-1) was obtained. The photoreceptor (A-1) had a configuration in which an intermediate layer, a charge generation layer, and a charge transport layer were laminated in this order on a conductive substrate.

[Photosensitive members (A-2) to (A-21) and photosensitive members (B-1) to (B-4)]
Instead of the hole transport agent (HTM-1), the hole transport agents listed in Table 1 were used. As the binder resin, the binder resins shown in Table 1 were used in place of the polyarylate resin (R-1). As the phthalocyanine pigment, the types and contents of the pigments shown in Table 1 were used instead of 0.04 part by mass of the X-type metal-free phthalocyanine pigment. In this way, photoreceptors (A-2) to (A-21) and photoreceptors (B-1) to (B-4) were obtained, respectively.

Table 1 shows the structures of the photoconductors (A-1) to (A-21) and the photoconductors (B-1) to (B-4). In the column “Binder resin type”, R-1 to R-6 indicate polyarylate resins (R-1) to (R-4) and binder resins (R-5) to (R-6), respectively. The column “molecular weight of the binder resin” indicates the viscosity average molecular weight. X-H ₂ Pc, Y-TiOPc, α-TiOPc, and ε-CuPc in the column “Types of phthalocyanine pigments” are X-type metal-free phthalocyanine pigment, Y-type titanyl phthalocyanine pigment, α-type titanyl phthalocyanine pigment, and An ε-type copper phthalocyanine pigment is shown. The column “content of phthalocyanine pigment” indicates the content of phthalocyanine pigment with respect to 100 parts by mass of the binder resin in the charge transport layer. The columns “HTM-1 to HTM-12” in the “hole transport agent” indicate the hole transport agents (HTM-1) to (HTM-12), respectively.

<Evaluation of sensitivity characteristics: measurement of potential V _L after exposure>
(Potential environment stability)
Using either a drum sensitivity tester (manufactured by Gentec Co., Ltd.) or any of photoconductors (A-1) to (A-21) and photoconductors (B-1) to (B-4) Charging was performed under conditions of several 31 rpm and a charging potential of −600V. Next, monochromatic light (wavelength: 780 nm) was extracted from the light of the halogen lamp using a bandpass filter and irradiated on the surface of the photoreceptor. The surface potential after 80 milliseconds had elapsed after the end of monochromatic light irradiation was measured. A plurality of post-exposure potentials were measured by increasing the exposure dose from 0.05 μJ / cm ² to 1.0 μJ / cm ² . The measurement of the post-exposure potential was performed in a low temperature and low humidity environment (LL environment: temperature 10 ° C. and relative humidity 15% RH) or a high temperature and high humidity environment (HH environment: temperature 30 ° C. and relative humidity 85% RH). A linear function was obtained by linearly approximating a plurality of post-exposure potentials with respect to the exposure amount using the least square method. The exposure amount when the post-exposure potential was −300 V was calculated using a linear function. The exposure amount obtained was E1 / 2 (unit: μJ / cm ² ). Specifically, E1 / 2 obtained from the post-exposure potential measured in the LL environment is defined as E1 / 2 (LL), and E1 / 2 obtained from the post-exposure potential measured in the HH environment is represented as E1 / 2 (HH). did. ΔE1 / 2 was calculated from the obtained E1 / 2 (LL) and E1 / 2 (HH) using Equation (1).
ΔE1 / 2 = E1 / 2 (LL) −E1 / 2 (HH) (1)
It shows that stability with respect to the temperature / humidity environment (potential environment stability) of the potential after exposure is excellent as the value of ΔE1 / 2 is small. Table 2 shows the evaluation results of the potential environment stability.

(HH repeatability)
Using either a drum sensitivity tester (manufactured by Gentec Co., Ltd.) or any of photoconductors (A-1) to (A-21) and photoconductors (B-1) to (B-4) Charging was performed under conditions of several 31 rpm and a charging potential of −600V. Next, monochromatic light (wavelength: 780 nm, exposure amount: 0.8 μJ / cm ² ) was taken out from the light of the halogen lamp using a bandpass filter and irradiated on the surface of the photoreceptor. The surface potential of the photoreceptor was measured 80 milliseconds after the exposure light irradiation. The obtained surface potential was defined as the initial post-exposure potential (V _L0 ). Next, the surface of the photosensitive member was irradiated with monochromatic light (wavelength: 660 nm, exposure amount: 5 μJ / cm ² ) to remove static electricity. Such charge-exposure-static charge was repeated, and the photoreceptor was rotated 10,000 times. Next, charging and exposure were performed under the same conditions, and the post-exposure potential was measured 80 milliseconds after the exposure light was irradiated. The obtained surface potential was taken as the post-exposure potential after 10,000 revolutions (V _L10,000 ). Measurement of the post-exposure potential was performed in an HH environment (temperature 30 ° C. and relative humidity 85% RH). ΔV _L was calculated from V _L0 and V _L10,000 using Equation (2).
ΔV _L = | V _L0 −V _L10,000 | (2)
It shows that the smaller the value of ΔV _L, the better the repeated stability (HH repeatability) of the post-exposure potential in the HH environment. Table 2 shows the evaluation results of the HH repetition characteristics.

<Evaluation of abrasion resistance of photoconductor: measurement of wear loss>
The coating solution for the charge transport layer prepared in the production of any one of the photoconductors (A-1) to (A-21) and the photoconductors (B-1) to (B-4) was used as an aluminum pipe (diameter: 78 mm). The film was applied to a polypropylene sheet (thickness 0.3 mm) wound around the film to form a coating film. The coating film was dried at 120 ° C. for 40 minutes. As a result, a wear evaluation test sheet on which a charge transport layer having a thickness of 30 μm was formed was produced.

The charge transport layer was peeled off from this polypropylene sheet and attached to a wheel S-36 (manufactured by Taber) to prepare a sample. The prepared sample is set in a rotary abrasion tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.), wear wheel CS-10 (manufactured by Taber), and rotated 1,000 times under conditions of load 500 gf and rotation speed 60 rpm, wear evaluation test Carried out. Wear loss (mg / 1000 rotations), which is a change in mass of the sample before and after the wear evaluation test, was measured. The wear resistance of the photoreceptor was evaluated based on the obtained wear loss. Table 2 shows the evaluation results of wear resistance.

As shown in Table 1, in the photoreceptors (A-1) to (A-21), the photosensitive layer was a laminated photosensitive layer. The photosensitive layer was provided with a charge generation layer and a charge transport layer. The charge transport layer contained a hole transport agent, any of polyarylate resins (R-1) to (R-4) as binder resins, and a phthalocyanine pigment. The content of the phthalocyanine pigment in the charge transport layer was 0.01 parts by mass or more and 1.00 parts by mass or less with respect to 100 parts by mass of the binder resin. The polyarylate resins (R-1) to (R-4) were polyarylate resins represented by the general formula (1). As shown in Table 2, in the photoconductors (A-1) to (A-21), the wear loss was 2.8 mg to 3.7 mg.

As shown in Table 1, in the photoreceptor (B-1), the charge transport layer did not contain a phthalocyanine pigment. In the photoconductors (B-2) and (B-3), the charge transport layer contained binder resins (R-5) and (R-6), respectively. The binder resins (R-5) and (R-6) were not polyarylate resins represented by the general formula (1). In the photoreceptor (B-4), the content of the phthalocyanine pigment in the charge transport layer was 2.00 masses with respect to 100 mass parts of the binder resin. As shown in Table 2, in the photoconductors (B-1) to (B-4), the wear loss was 4.0 mg or more and 11.4 mg or less.

As is clear from Tables 1 and 2, the photoconductors (A-1) to (A-21) were superior in wear resistance to the photoconductors (B-1) to (B-4).

As shown in Table 1, in the photoreceptor (A-4), the charge transport layer contained a polyarylate resin (R-4) as a binder resin. As shown in Table 2, the abrasion loss of the photoreceptor (A-4) was 2.8 mg.

As shown in Table 1, in the photoreceptors (A-1) to (A-3), the charge transport layer is made of any one of polyarylate resins (R-1) to (R-3) as a binder resin. Included. As shown in Table 2, in the photoconductors (A-1) to (A-3), the wear loss was 3.5 mg or more and 3.7 mg or less.

As is apparent from Tables 1 and 2, the photoconductor (A-4) was superior in wear resistance to the photoconductors (A-1) to (A-3).

The electrophotographic photosensitive member according to the present invention can be used in an image forming apparatus such as a multifunction machine.

Claims (10)

1. An electrophotographic photosensitive member comprising a conductive substrate and a photosensitive layer,
   The photosensitive layer includes a charge generation layer and a charge transport layer,
   The charge generation layer includes a charge generation agent,
   The charge transport layer includes a hole transport agent, a binder resin, and a phthalocyanine pigment,
   The binder resin includes a polyarylate resin,
   The polyarylate resin is represented by the general formula (1),
   The electrophotographic photoreceptor, wherein the content of the phthalocyanine pigment is 0.01 parts by mass or more and 1.00 parts by mass or less with respect to 100 parts by mass of the binder resin.
   

   

   In the general formula (1),
   kt represents 2 or 3,
   X represents a divalent group represented by the chemical formula (2A), the chemical formula (2B), the chemical formula (2C), or the chemical formula (2D).
   

   
2. In the general formula (1),
   kt represents 3,
   2. The electrophotographic photoreceptor according to claim 1, wherein X represents the divalent group represented by the chemical formula (2B), the chemical formula (2C), or the chemical formula (2D).
3. 2. The electrophotographic photosensitive member according to claim 1, wherein the polyarylate resin is represented by a chemical formula (R-1), a chemical formula (R-2), a chemical formula (R-3), or a chemical formula (R-4).
   

   

   

   

   
4. 2. The electrophotographic photoreceptor according to claim 1, wherein the phthalocyanine pigment is an X-type metal-free phthalocyanine pigment, a Y-type titanyl phthalocyanine pigment, an α-type titanyl phthalocyanine pigment, or an ε-type copper phthalocyanine pigment.
5. The said hole transport agent contains the compound represented by General formula (2), General formula (3), General formula (4), General formula (5), or General formula (6). Electrophotographic photoreceptor.
   

   

   In the general formula (2),
   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, and the phenyl group is an alkyl group having 1 to 8 carbon atoms. You may have
   Q ₂ 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 (3),
   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 phenylene group may be the same or different from each other;
   k represents 0 or 1.
   

   

   In the general formula (4),
   R _a , R _b and R _c each independently represents an alkyl group having 1 to 8 carbon atoms, a phenyl group, or an alkoxy group having 1 to 8 carbon atoms,
   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 phenylene 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 (5),
   R ¹ , R ² , and R ³ are each independently an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, a carbon atom Represents an aryloxy group having 6 to 14 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a halogen atom, or a hydrogen atom,
   R ² and R ³ may be bonded to each other,
   d represents 1 or 2.
   

   

   In the general formula (6),
   R ¹¹¹ and R ¹¹² are each independently an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, or 6 to 14 carbon atoms. Represents the following aryloxy group, an aralkyl group having 7 to 20 carbon atoms, or a halogen atom;
   d ₁ and d ₂ each independently represents an integer of 0 to 5,
   d ₃ represents 1 or 2.
6. In the general formula (2),
   Q ₁ represents a phenyl group or a hydrogen atom, and the phenyl group has 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 (3),
   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 (4),
   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 (5),
   R ¹ , R ² , and R ³ each represents an aryl group having 6 to 14 carbon atoms,
   R ² and R ³ may be bonded to each other,
   In the general formula (6),
   R ¹¹¹ and R ¹¹² each represents an alkyl group having 1 to 6 carbon atoms,
   d ₁ and d ₂ each independently represent 0 or 1,
   The electrophotographic photosensitive member according to claim 5, wherein d ₃ represents 1.
7. The hole transport agent includes chemical formula (HTM-1), chemical formula (HTM-2), chemical formula (HTM-3), chemical formula (HTM-4), chemical formula (HTM-5), chemical formula (HTM-6), chemical formula (HTM-7), chemical formula (HTM-8), chemical formula (HTM-9), chemical formula (HTM-10), chemical formula (HTM-11), or chemical formula (HTM-12). The electrophotographic photosensitive member described.
   

   

   

   

   
8. The electrophotographic photosensitive member according to claim 1, wherein the charge generator is a Y-type titanyl phthalocyanine pigment.
9. In the general formula (1),
   The electrophotographic photoreceptor according to claim 1, wherein X represents the divalent group represented by the chemical formula (2D).
10. The electrophotographic photoreceptor according to claim 1, wherein the hole transport agent is a compound represented by the general formula (3) or (4).
    
    

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