JP7310329B2 - Electrophotographic photoreceptor, image forming apparatus, and electrophotographic photoreceptor manufacturing method - Google Patents

Description

The present invention relates to an electrophotographic photoreceptor, an image forming apparatus, and a method for manufacturing an electrophotographic photoreceptor.

An electrophotographic photoreceptor is used as an image carrier in an electrophotographic image forming apparatus (for example, a printer or a multifunction machine). An electrophotographic photoreceptor has a photosensitive layer. As the electrophotographic photoreceptor, for example, a single-layer electrophotographic photoreceptor and a laminated electrophotographic photoreceptor are used. A single-layer electrophotographic photoreceptor includes a single-layer photosensitive layer having a charge generation function and a charge transport function. A laminated electrophotographic photoreceptor includes a photosensitive layer including a charge generation layer having a charge generation function and a charge transport layer having a charge transport function.

US Pat. No. 4,900,002 describes an imaging element with a charge transport layer containing a diamine compound of particular structure.

JP-A-56-119132

However, investigations by the present inventors have revealed that the imaging element described in Patent Document 1 is insufficient in terms of crack resistance and crystallization suppression.

The present invention has been made in view of the above problems, and an object thereof is to provide an electrophotographic photoreceptor that is excellent in crack resistance and capable of suppressing crystallization. Another object of the present invention is to provide an image forming apparatus which is equipped with such an electrophotographic photoreceptor and is capable of forming excellent images with excellent durability. Another object of the present invention is to produce an electrophotographic photoreceptor that is excellent in crack resistance and capable of suppressing crystallization while simplifying the production process of a hole transport agent.

The electrophotographic photoreceptor of the present invention comprises a conductive substrate and a photosensitive layer. The photosensitive layer is a single layer. The photosensitive layer contains a charge generating agent, a hole transporting agent, an electron transporting agent, and a binder resin. The hole transport agent includes a first hole transport agent and a second hole transport agent. The first hole transport agent is a compound represented by general formula (1). The second hole transport agent is a compound represented by general formula (2). The electron transport agent includes a compound represented by general formula (10), (11), or (12).

In general formula (1), R ^1A , R ^2A , R ^3A , R ^4A , R ^5A , R ^6A , R ^7A , R ^8A , R ^9A , and R ^10A each independently represent a hydrogen atom and a number of carbon atoms; It represents an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or an aryl group having 6 to 14 carbon atoms. R ^1B in the general formula (1) and R ^1C in the general formula (2) represent the same groups as R ^1A in the general formula (1). R ^2B in the general formula (1) and R ^2C in the general formula (2) represent the same groups as R ^2A in the general formula (1). R ^3B in the general formula (1) and R ^3C in the general formula (2) represent the same groups as R ^3A in the general formula (1). R ^4B in the general formula (1) and R ^4C in the general formula (2) represent the same groups as R ^4A in the general formula (1). R ^5B in the general formula (1) and R ^5C in the general formula (2) represent the same groups as R ^5A in the general formula (1). R ^6B in the general formula (1) and R ^6C and R ^6D in the general formula (2) represent the same groups as R ^6A in the general formula (1). R ^7B in the general formula (1) and R ^7C and R ^7D in the general formula (2) represent the same groups as R ^7A in the general formula (1). R ^8B in the general formula (1) and R ^8C and R ^8D in the general formula (2) represent the same groups as R ^8A in the general formula (1). R ^9B in the general formula (1) and R ^9C and R ^9D in the general formula (2) represent the same groups as R ^9A in the general formula (1). R ^10B in the general formula (1) and R ^10C and R ^10D in the general formula (2) represent the same groups as R ^10A in the general formula (1). Y in the general formula (1) represents a divalent group represented by the chemical formula (Y2).

In general formula (10), ^Q5A and ^Q5B 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. Q ^6A and Q ^6B each independently represent an alkyl group having 1 to 8 carbon atoms, a phenyl group, or an alkoxy group having 1 to 8 carbon atoms. m ₁ and m ₂ each independently represent an integer of 0 or more and 4 or less. In general formula (11), Q ⁷ and Q ⁸ 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. ^Q9 represents an alkyl group having 1 to 8 carbon atoms, a phenyl group, or an alkoxy group having 1 to 8 carbon atoms; _m3 represents an integer of 0 to 4; In general formula (12), Q ¹⁰ and Q ¹¹ each independently represent an alkyl group having 1 to 6 carbon atoms or a hydrogen atom. ^Q12 represents a halogen atom or a hydrogen atom.

An image forming apparatus of the present invention includes an image carrier, a charging device, an exposure device, a developing device, and a transfer device. The charging device positively charges the surface of the image carrier. The exposure device exposes the charged surface of the image carrier to form an electrostatic latent image on the surface of the image carrier. The developing device develops the electrostatic latent image into a toner image. The transfer device transfers the toner image from the image bearing member to a transfer receiving member. The image carrier is the above electrophotographic photoreceptor.

The method for manufacturing an electrophotographic photoreceptor of the present invention includes a hole transport agent manufacturing step and a photosensitive layer forming step. The hole transport agent is manufactured in the hole transport agent manufacturing step. In the photosensitive layer forming step, a coating liquid containing the charge generating agent, the hole transporting agent, the electron transporting agent, the binder resin, and the solvent is applied onto the conductive substrate, and the At least part of the solvent is removed to form the photosensitive layer. The hole transport agent manufacturing process includes a first stirring process and a second stirring process. In the first stirring step, the mixed liquid containing the compound represented by the general formula (A) and the compound represented by the general formula (B) is first stirred. In the second stirring step, the compound represented by the general formula (C) is further added to the mixed liquid, and the mixed liquid is second stirred. The second stirring step is performed without purifying the mixed solution after the first stirring step. The hole transport agent containing the first hole transport agent and the second hole transport agent is obtained through the first stirring step and the second stirring step.

R ¹ , R ² , R ³ , R ⁴ and R ⁵ in general formula (A) are respectively R ^1A , R ^2A , R ^3A , R ^4A and R ^5A in general formula (1) represents the same group as R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ in general formula (B) are respectively R ^6A , R ^7A , R ^8A , R ^9A and R ^10A in general formula (1) represents the same group as Z ¹ in the general formula (B) represents a halogen atom. Y in the general formula (C) represents the same group as Y in the general formula (1). Z ² and Z ³ in the general formula (C) represent halogen atoms.

The electrophotographic photoreceptor of the present invention is excellent in crack resistance and can suppress crystallization. In addition, since the image forming apparatus of the present invention includes an electrophotographic photoreceptor that is excellent in crack resistance and capable of suppressing crystallization, it is possible to form excellent images with excellent durability. Further, according to the method of manufacturing a photoreceptor according to the present invention, it is possible to manufacture a photoreceptor that is excellent in crack resistance and capable of suppressing crystallization while simplifying the manufacturing process of the hole transport agent.

1 is a partial cross-sectional view of an electrophotographic photoreceptor according to an embodiment of the present invention; FIG. 1 is a partial cross-sectional view of an electrophotographic photoreceptor according to an embodiment of the present invention; FIG. 1 is a partial cross-sectional view of an electrophotographic photoreceptor according to an embodiment of the present invention; FIG. 1 is a cross-sectional view showing an example of an image forming apparatus; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is by no means limited to the following embodiments. The present invention can be implemented with appropriate modifications within the scope of the purpose of the present invention. It should be noted that descriptions of overlapping descriptions may be omitted as appropriate, but the gist of the invention is not limited. Hereinafter, compounds and derivatives thereof may be collectively referred to by adding "system" to the name of the compound. In addition, when the name of a polymer is expressed by adding "system" to the name of a compound, it means that the repeating unit of the polymer is derived from the compound or its derivative.

First, the substituents used in this specification are described. Halogen atoms (halogen groups) include, for example, fluorine atoms (fluoro groups), chlorine atoms (chloro groups), bromine atoms (bromo groups), and iodine atoms (iodo groups).

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, and an alkyl group having 2 to 4 carbon atoms are each unless otherwise specified. , linear or branched and unsubstituted. Examples of alkyl groups having 1 to 8 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, 1 -methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylpropyl group, 2-ethylpropyl group, 1,1-dimethylpropyl group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group, 1,2-dimethylpropyl group, n-hexyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 1,1-dimethylbutyl group, 1,2-dimethyl butyl group, 1,3-dimethylbutyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, 3,3-dimethylbutyl group, 1,1,2-trimethylpropyl group, 1,2,2 -trimethylpropyl, 1-ethylbutyl, 2-ethylbutyl and 3-ethylbutyl groups, linear and branched heptyl groups, and linear and branched octyl groups. Examples of alkyl groups having 1 to 6 carbon atoms, alkyl groups having 1 to 4 carbon atoms, and alkyl groups having 2 to 4 carbon atoms are respectively examples of alkyl groups having 1 to 8 carbon atoms. It is a group having the corresponding number of carbon atoms among the groups described as above.

An alkoxy group having 1 to 8 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 3 carbon atoms are linear or branched unless otherwise specified. is unsubstituted. Examples of alkoxy groups having 1 to 8 carbon atoms include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, 1-methylbutoxy group, 2-methylbutoxy group, 3-methylbutoxy group, 1-ethylpropoxy group, 2-ethylpropoxy group, 1,1-dimethylpropoxy group, 1,2-dimethylpropoxy group, 2,2- dimethylpropoxy group, 1,2-dimethylpropoxy group, n-hexyloxy group, 1-methylpentyloxy group, 2-methylpentyloxy group, 3-methylpentyloxy group, 4-methylpentyloxy group, 1,1- dimethylbutoxy group, 1,2-dimethylbutoxy group, 1,3-dimethylbutoxy group, 2,2-dimethylbutoxy group, 2,3-dimethylbutoxy group, 3,3-dimethylbutoxy group, 1,1,2- trimethylpropoxy, 1,2,2-trimethylpropoxy, 1-ethylbutoxy, 2-ethylbutoxy, 3-ethylbutoxy, linear and branched heptyloxy groups, and linear and A branched octyloxy group can be mentioned. Examples of the alkoxy group having 1 to 6 carbon atoms and the alkoxy group having 1 to 3 carbon atoms are each the corresponding carbon among the groups described as examples of the alkoxy group having 1 to 8 carbon atoms It is a group having the number of atoms.

Each aryl group having 6 to 14 carbon atoms and aryl group having 6 to 10 carbon atoms is unsubstituted unless otherwise specified. Examples of aryl groups having 6 to 14 carbon atoms include phenyl, naphthyl, indacenyl, biphenylenyl, acenaphthylenyl, anthryl and phenanthryl groups. Examples of the aryl group having 6 to 10 carbon atoms include a phenyl group and a naphthyl group. The substituents used in the present specification have been described above.

<Electrophotographic photoreceptor>
The present embodiment relates to an electrophotographic photoreceptor (hereinafter sometimes referred to as a photoreceptor). The photoreceptor 1 of this embodiment will be described below with reference to FIGS. 1 to 3. FIG. 1 to 3 each show a partial cross-sectional view of photoreceptor 1. FIG.

As shown in FIG. 1, the photoreceptor 1 includes, for example, a conductive substrate 2 and a photosensitive layer 3. As shown in FIG. The photosensitive layer 3 is a single layer. The photoreceptor 1 is a single layer electrophotographic photoreceptor having a single photosensitive layer 3 .

As shown in FIG. 2, the photoreceptor 1 may include a conductive substrate 2, a photosensitive layer 3, and an intermediate layer 4 (undercoat layer). An intermediate layer 4 is provided between the conductive substrate 2 and the photosensitive layer 3 . The photosensitive layer 3 may be provided directly on the conductive substrate 2, as shown in FIG. Alternatively, as shown in FIG. 2, the photosensitive layer 3 may be provided on the conductive substrate 2 with an intermediate layer 4 interposed therebetween.

As shown in FIG. 3, the photoreceptor 1 may comprise a conductive substrate 2, a photosensitive layer 3, and a protective layer 5. As shown in FIG. A protective layer 5 is provided on the photosensitive layer 3 . As shown in FIGS. 1 and 2, it is preferable that the photosensitive layer 3 is provided as the outermost layer of the photoreceptor 1 . Since the photosensitive layer 3 containing a predetermined hole transport agent and a predetermined electron transport agent, which will be described later, is provided as the outermost layer, even if the cleaning agent remains on the surface of the photoreceptor 1 during maintenance, Cracks are less likely to occur in the photosensitive layer 3 . In addition, as shown in FIG. 3, a protective layer 5 may be provided as the outermost surface layer of the photoreceptor 1 .

The photosensitive layer 3 contains at least a charge generating agent, a hole transporting agent, an electron transporting agent and a binder resin. The photosensitive layer 3 may further contain additives as necessary.

Although the thickness of the photosensitive layer 3 is not particularly limited, it is preferably 5 μm or more and 100 μm or less, more preferably 10 μm or more and 50 μm or less. The photoreceptor 1 has been described above with reference to FIGS. 1 to 3. FIG.

(Charge generating agent)
Examples of charge generating agents include phthalocyanine pigments, perylene pigments, bisazo pigments, trisazo pigments, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaline pigments, indigo pigments, azulenium pigments, cyanine pigments, Pigments, powders of inorganic photoconductive materials (e.g. selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, and amorphous silicon), pyrylium pigments, anthanthrone-based pigments, triphenylmethane-based pigments, threne-based pigments, toluidine-based pigments , pyrazoline-based pigments, and quinacridone-based pigments. The photosensitive layer may contain only one type of charge generating agent, or may contain two or more types.

A phthalocyanine pigment is a pigment having a phthalocyanine structure. Examples of phthalocyanine pigments include metal-free phthalocyanines and metal phthalocyanines. Metal phthalocyanines include, for example, titanyl phthalocyanine, hydroxygallium phthalocyanine, and chlorogallium phthalocyanine. A metal-free phthalocyanine is represented by the chemical formula (CGM-1). Titanyl phthalocyanine is represented by the chemical formula (CGM-2).

The phthalocyanine pigment may be crystalline or amorphous. Examples of metal-free phthalocyanine crystals include X-type crystals of metal-free phthalocyanine (hereinafter sometimes referred to as X-type metal-free phthalocyanine). Examples of titanyl phthalocyanine crystals include α-type, β-type, and Y-type crystals of titanyl phthalocyanine (hereinafter sometimes referred to as α-type, β-type, and Y-type titanyl phthalocyanine).

For example, it is preferable to use a photoreceptor having sensitivity in a wavelength region of 700 nm or more for a digital optical image forming apparatus (for example, a laser beam printer or facsimile using a light source such as a semiconductor laser). As the charge generating agent, a phthalocyanine-based pigment is preferred, metal-free phthalocyanine or titanyl phthalocyanine is more preferred, titanyl phthalocyanine is still more preferred, and Y-type titanyl phthalocyanine is particularly preferred, since it has a high quantum yield in a wavelength region of 700 nm or more. .

Y-type titanyl phthalocyanine has a main peak at, for example, a Bragg angle (2θ±0.2°) of 27.2° in its CuKα characteristic X-ray diffraction spectrum. The main peak in the CuKα characteristic X-ray diffraction spectrum is the peak having the first or second highest intensity in the range where the Bragg angle (2θ±0.2°) is 3° or more and 40° or less. Y-type titanyl phthalocyanine does not have a peak at 26.2° C. in its CuKα characteristic X-ray diffraction spectrum.

The CuKα characteristic X-ray diffraction spectrum can be measured, for example, by the following method. First, a sample (titanyl phthalocyanine) is filled in a sample holder of an X-ray diffraction device (for example, "RINT (registered trademark) 1100" manufactured by Rigaku Corporation), and the X-ray tube Cu, tube voltage 40 kV, tube current 30 mA, Also, the X-ray diffraction spectrum is measured under the condition that the wavelength of the CuKα characteristic X-ray is 1.542 Å. The measurement range (2θ) is, for example, 3° or more and 40° or less (start angle: 3°, stop angle: 40°), and the scanning speed is, for example, 10°/min. A main peak is determined from the obtained X-ray diffraction spectrum, and the Bragg angle of the main peak is read.

The content of the charge generating agent is preferably 0.1 parts by mass or more and 50 parts by mass or less, more preferably 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.

(Hole transport agent)
The hole transport agent includes a first hole transport agent and a second hole transport agent. The first hole transport agent is a compound represented by general formula (1). The second hole transport agent is a compound represented by general formula (2). Hereinafter, the compounds represented by formulas (1) and (2) may be referred to as hole transport agents (1) and (2), respectively.

In general formula (1), R ^1A , R ^2A , R ^3A , R ^4A , R ^5A , R ^{6A , R 7A ,} R ^8A , R ^9A , and R ^10A each independently represent a hydrogen atom and 1 carbon atom. represents an alkyl group having at least 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or an aryl group having 6 to 14 carbon atoms. R ^1B in general formula (1) and R ^1C in general formula (2) represent the same groups as R ^1A in general formula (1). R ^2B in general formula (1) and R ^2C in general formula (2) represent the same groups as R ^2A in general formula (1). R ^3B in general formula (1) and R ^3C in general formula (2) represent the same groups as R ^3A in general formula (1). R ^4B in general formula (1) and R ^4C in general formula (2) represent the same groups as R ^4A in general formula (1). R ^5B in general formula (1) and R ^5C in general formula (2) represent the same groups as R ^5A in general formula (1). R ^6B in general formula (1) and R ^6C and R ^6D in general formula (2) represent the same groups as R ^6A in general formula (1). R ^7B in general formula (1) and R ^7C and R ^7D in general formula (2) represent the same groups as R ^7A in general formula (1). R ^8B in general formula (1) and R ^8C and R ^8D in general formula (2) represent the same groups as R ^8A in general formula (1). R ^9B in general formula (1) and R ^9C and R ^9D in general formula (2) represent the same groups as R ^9A in general formula (1). R ^10B in general formula (1) and R ^10C and R ^10D in general formula (2) represent the same groups as R ^10A in general formula (1). Y in general formula (1) represents a divalent group represented by chemical formula (Y2).

By containing both the hole transport agents (1) and (2) in the photosensitive layer, the crack resistance of the photoreceptor can be improved and crystallization of the photoreceptor can be suppressed. The crack resistance of the photoreceptor is a characteristic that can suppress the occurrence of cracks in the photoreceptor layer even when the cleaning agent remains on the surface of the photoreceptor 1 during maintenance. Here, the hole transport agent (2) is a by-product generated when synthesizing the final product, the hole transport agent (1). Purification typically removes by-products to provide the final product. However, the present inventors intentionally mixed the hole transport agent (2) with the hole transport agent (1) without completely removing the hole transport agent (2), which is a by-product, by purification. It has been found that the crack resistance of the photoreceptor is improved by The present inventors also found that the hole transport agent (2) suppresses aggregation of the hole transport agent (1), thereby suppressing crystallization of the photoreceptor. Further, the photoreceptor of the present embodiment comprises a photoreceptor layer containing a hole transport agent (1) having excellent sensitivity characteristics. Therefore, the crack resistance of the photoreceptor can be improved and the crystallization of the photoreceptor can be suppressed without impairing the sensitivity characteristics of the photoreceptor.

as an alkyl group having 1 to 8 carbon atoms represented by R ^1A , R ^2A , R ^3A , R ^4A , R ^5A , R ^6A , R ^7A , R ^8A , R ^9A and R ^10A in general formula (1) is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and still more preferably a methyl group or an ethyl group.

as an alkoxy group having 1 to 8 carbon atoms represented by R ^1A , R ^2A , R ^3A , R ^4A , R ^5A , R ^6A , R ^7A , R ^8A , R ^9A and R ^10A in general formula (1); is preferably an alkoxy group having 1 to 6 carbon atoms, more preferably an alkoxy group having 1 to 3 carbon atoms, and still more preferably a methoxy group.

as an aryl group having 6 to 14 carbon atoms represented by R ^1A , R ^2A , R ^3A , R ^4A , R ^5A , R ^6A , R ^7A , R ^8A , R ^9A and R ^10A in general formula (1); is preferably an aryl group having 6 to 10 carbon atoms.

In order to improve the crack resistance of the photoreceptor and suppress crystallization, R ^1A , R ^2A , R ^3A , R ^4A , R ^5A , R ^6A , R ^7A , R ^8A and R ^9A in general formula (1) , and at least two of R ^10A represent groups other than hydrogen atoms, and R ^1A , R ^2A , R 3A , R ^4A , R ^5A , R ^6A , R ^7A , ^{R 8A ,} R ^9A , and R ^10A preferably represent hydrogen atoms. Moreover, the total number of carbon atoms of the groups other than hydrogen atoms is preferably 3 or more. In general formula (1), groups other than hydrogen atoms represented by R ^1A , R ^2A , R ^3A , R ^4A , R 5A , R ^6A , R ^7A , ^{R 8A ,} R ^9A , and R ^10A are carbon atoms It is an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or an aryl group having 6 to 14 carbon atoms.

In general formula (1), R ^3A preferably represents an alkoxy group having 1 to 8 carbon atoms in order to improve the crack resistance of the photoreceptor and suppress crystallization.

In general formula (1), one or two of R ^1A , R ^3A and R ^5A have 1 to 8 carbon atoms in order to improve the crack resistance of the photoreceptor and suppress crystallization. or an alkoxy group having 1 to 8 carbon atoms, the remainder of R ^1A , R ^3A and R ^5A represent hydrogen atoms, and R ^2A and R ^4A each represent a hydrogen atom is preferably represented.

In general formula (1), R ^8A represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ^6A and R ^{7A are} , R ^9A and R ^10A preferably represent a hydrogen atom.

In order to improve the crack resistance of the photoreceptor and suppress crystallization, the hole transport agent (1) is a compound represented by the chemical formula (HTM-1), and the hole transport agent (2) is A compound represented by the chemical formula (HTM-A) is preferred. For the same reason, the hole transport agent (1) is a compound represented by the chemical formula (HTM-2), and the hole transport agent (2) is a compound represented by the chemical formula (HTM-B). is preferred. For the same reason, the hole transport agent (1) is a compound represented by the chemical formula (HTM-3), and the hole transport agent (2) is a compound represented by the chemical formula (HTM-C). is preferred. For the same reason, the hole transport agent (1) is a compound represented by the chemical formula (HTM-4), and the hole transport agent (2) is a compound represented by the chemical formula (HTM-D). is preferred. Hereinafter, the compounds represented by chemical formulas (HTM-1) to (HTM-4) may be referred to as hole transport agents (HTM-1) to (HTM-4), respectively. Further, the compounds represented by the chemical formulas (HTM-A) to (HTM-D) are sometimes described as hole transport agents (HTM-A) to (HTM-D), respectively.

The content of the hole transport agent (2) with respect to the total mass of the hole transport agents (1) and (2) is preferably 1.0% by mass or more and 30.0% by mass or less, and is 1.0% by mass. % or more and 10.0 mass % or less, and more preferably 2.0 mass % or more and 5.0 mass % or less. When the content of the hole transport agent (2) with respect to the total mass of the hole transport agents (1) and (2) is 1.0% by mass or more, the crack resistance of the photoreceptor can be further improved. Crystallization can be further suppressed. When the content of the hole transport agent (2) with respect to the total mass of the hole transport agents (1) and (2) is 30.0% by mass or less, the sensitivity characteristics of the photoreceptor can be improved. A method for adjusting the content of the hole transporting agent (2) with respect to the total mass of the hole transporting agents (1) and (2) will be described later in <Method for Producing Photoreceptor>.

The total content of the hole transport agents (1) and (2) is preferably 10 parts by mass or more and 200 parts by mass or less, and 50 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the binder resin. More preferably, it is 60 parts by mass or more and 80 parts by mass or less.

The photosensitive layer may contain only hole transport agents (1) and (2) as hole transport agents. Alternatively, in the photosensitive layer, in addition to the hole transport agents (1) and (2), other hole transport agents (hereinafter sometimes referred to as other hole transport agents) are used as the hole transport agent. may further contain. Other hole transport agents include, for example, triphenylamine derivatives, diamine derivatives (e.g., N,N,N',N'-tetraphenylbenzidine derivatives, N,N,N',N'-tetraphenylphenylenediamine derivatives, N,N,N',N'-tetraphenylnaphthylenediamine derivatives, N,N,N',N'-tetraphenylphenanthrylenediamine derivatives, and di(aminophenylethenyl)benzene derivatives), oxa Diazole compounds (e.g., 2,5-di(4-methylaminophenyl)-1,3,4-oxadiazole), styryl compounds (e.g., 9-(4-diethylaminostyryl)anthracene), carbazole compounds compounds (e.g., polyvinylcarbazole), organic polysilane compounds, pyrazoline compounds (e.g., 1-phenyl-3-(p-dimethylaminophenyl)pyrazoline), hydrazone compounds, indole compounds, oxazole compounds, isoxazole compounds , thiazole-based compounds, thiadiazole-based compounds, imidazole-based compounds, pyrazole-based compounds, and triazole-based compounds.

(Electron transport agent)
The electron transport agent is a compound represented by general formula (10), (11), or (12) (hereinafter referred to as electron transport agents (10), (11), and (12), respectively). )including. The photosensitive layer contains both the hole transport agents (1) and (2) as well as the electron transport agent (10), (11), or (12), thereby improving the crack resistance of the photoreceptor. , the crystallization of the photoreceptor can be particularly suppressed.

In general formula (10), ^Q5A and ^Q5B 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. Q ^6A and Q ^6B each independently represent an alkyl group having 1 to 8 carbon atoms, a phenyl group, or an alkoxy group having 1 to 8 carbon atoms. m ₁ and m ₂ each independently represent an integer of 0 or more and 4 or less.

When m ₁ represents an integer of 2 or more and 4 or less, multiple Q ^6A may be the same or different. When m ₂ represents an integer of 2 or more and 4 or less, multiple Q ^6Bs may be the same or different.

In general formula (10), Q ^5A and Q ^5B each independently preferably represent an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms. , more preferably represents a 1,1-dimethylpropyl group. m ₁ and m ₂ preferably represent zero.

In general formula (11), ^Q7 and ^Q8 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. Q ⁹ represents an alkyl group having 1 to 8 carbon atoms, a phenyl group, or an alkoxy group having 1 to 8 carbon atoms. m ₃ represents an integer of 0 or more and 4 or less.

When m ₃ represents an integer of 2 or more and 4 or less, multiple Q ^9s may be the same or different.

In general formula (11), Q ⁷ and Q ⁸ each independently preferably represent an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms. , more preferably represents a tert-butyl group. m ₃ preferably represents 0.

In general formula (12), Q ¹⁰ and Q ¹¹ each independently represent an alkyl group having 1 to 6 carbon atoms or a hydrogen atom. ^Q12 represents a halogen atom or a hydrogen atom.

In general formula (12), Q ¹⁰ and Q ¹¹ preferably each independently represent an alkyl group having 1 to 6 carbon atoms, more preferably a tert-butyl group. Q ¹² preferably represents a halogen atom, more preferably a chlorine atom.

A compound represented by the chemical formula (E-1) is preferable as the electron transport agent (10) in order to improve the crack resistance of the photoreceptor and suppress crystallization. For the same reason, the compound represented by the chemical formula (E-2) is preferable as the electron transport agent (11). For the same reason, the compound represented by the chemical formula (E-3) is preferable as the electron transport agent (12). Hereinafter, the compounds represented by chemical formulas (E-1), (E-2), and (E-3) are used as electron transport agents (E-1), (E-2), and (E-3), respectively. ) may be described.

The content of the electron transport agent is preferably 5 parts by mass or more and 150 parts by mass or less, more preferably 10 parts by mass or more and 50 parts by mass or less, and 20 parts by mass or more with respect to 100 parts by mass of the binder resin. It is more preferably 40 parts by mass or less.

The photosensitive layer may contain only one electron transport agent, or may contain two or more electron transport agents. The photosensitive layer may further contain an electron transport agent other than the electron transport agents (10), (11) and (12) (hereinafter sometimes referred to as other electron transport agents). Other electron transport agents include, for example, quinone-based compounds, diimide-based compounds, hydrazone-based compounds, malononitrile-based compounds, thiopyran-based compounds, trinitrothioxanthone-based compounds, and 3,4,5,7-tetranitro-9-fluorenone-based compounds. compounds, dinitroanthracene-based compounds, dinitroacridine-based compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroacridine, succinic anhydride, maleic anhydride, and dibromomaleic anhydride. Examples of quinone compounds include diphenoquinone compounds, azoquinone compounds, anthraquinone compounds, naphthoquinone compounds, nitroanthraquinone compounds, and dinitroanthraquinone compounds.

(binder resin)
Examples of binder resins include thermoplastic resins, thermosetting resins, and photocurable resins. Examples of thermoplastic resins include polyarylate resins, polycarbonate resins, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, acrylic acid polymers, styrene-acrylic acid copolymers, Polyethylene resin, ethylene-vinyl acetate copolymer, chlorinated polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer resin, vinyl chloride-vinyl acetate copolymer, alkyd resin, polyamide resin, urethane resin, polysulfone resin, diallyl phthalate Resins, ketone resins, polyvinyl butyral resins, polyester resins, polyvinyl acetal resins, and polyether resins. Thermosetting resins include, for example, silicone resins, epoxy resins, phenolic resins, urea resins, and melamine resins. Examples of photocurable resins include acrylic acid adducts of epoxy compounds and acrylic acid adducts of urethane compounds. The photosensitive layer may contain only one binder resin, or may contain two or more binder resins.

The viscosity average molecular weight of the binder resin is preferably 10,000 or more, more preferably 20,000 or more, still more preferably 30,000 or more, and particularly preferably 40,000 or more. . When the viscosity average molecular weight of the binder resin is 10,000 or more, the wear resistance of the photoreceptor can be improved. On the other hand, the viscosity average molecular weight of the binder resin is preferably 80,000 or less, more preferably 70,000 or less. When the viscosity-average molecular weight of the binder resin is 80,000 or less, the binder resin is easily dissolved in the solvent for forming the photosensitive layer.

As the binder resin, a polyarylate resin or a polycarbonate resin is preferred, and a polyarylate resin is more preferred. The polyarylate resin and the polycarbonate resin will be described in order below.

First, the polyarylate resin will be explained. In order to particularly improve the crack resistance of the photoreceptor and suppress crystallization, preferable examples of the polyarylate resin include at least one type of repeating unit represented by the general formula (10) and at least one type of and a repeating unit represented by general formula (11). Hereinafter, a polyarylate resin containing at least one repeating unit represented by the general formula (10) and at least one repeating unit represented by the general formula (11) is referred to as a polyarylate resin (PA). I have something to do. Also, the repeating units represented by formulas (10) and (11) may be referred to as repeating units (10) and (11), respectively.

In general formula (10), R ¹¹ and R ¹² each independently represent a hydrogen atom or a methyl group. In general formula (10), W represents a divalent group represented by general formula (W1), general formula (W2), or chemical formula (W3).

In general formula (W1), R ¹³ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ¹⁴ represents an alkyl group having 1 to 4 carbon atoms. In general formula (W2), t represents an integer of 1 or more and 3 or less.

In general formula (11), X represents a divalent group represented by chemical formula (X1), chemical formula (X2), or chemical formula (X3).

The alkyl group having 1 to 4 carbon atoms represented by R ¹³ in general formula (W1) is preferably a methyl group. The alkyl group having 1 to 4 carbon atoms represented by R ¹⁴ in general formula (W1) is preferably an alkyl group having 2 to 4 carbon atoms, more preferably an ethyl group. It is preferable that t in the general formula (W2) represents 2.

In general formula (10), R ¹¹ and R ¹² preferably represent a methyl group. In general formula (10), W preferably represents a divalent group represented by general formula (W2). In general formula (11), X preferably represents a divalent group represented by chemical formulas (X1) and (X3).

Preferable examples of the repeating unit (10) include repeating units represented by chemical formulas (10-1), (10-2) and (10-3). Hereinafter, repeating units represented by chemical formulas (10-1), (10-2), and (10-3) are replaced with repeating units (10-1), (10-2), and (10-3), respectively. ) may be described.

Preferable examples of repeating unit (11) include repeating units represented by chemical formulas (11-X1), (11-X2) and (11-X3). Hereinafter, the repeating units represented by chemical formulas (11-X1), (11-X2), and (11-X3) are replaced with repeating units (11-X1), (11-X2), and (11-X3), respectively. ) may be described.

The polyarylate resin (PA) may contain only one repeating unit (10), or may contain two or more repeating units (10). The polyarylate resin (PA) may contain only one repeating unit (11), or may contain two or more repeating units (11). The polyarylate resin (PA) preferably contains at least one type of repeating unit (10) and at least two types of repeating unit (11), and one type of repeating unit (10) and two types of repeating unit (11 ) and more preferably.

Preferred examples of polyarylate resins (PA) include polyarylate resins containing repeating units (10-2), (11-X1), and (11-X3) (hereinafter referred to as polyarylate resin (I) may be used).

A more suitable example of the polyarylate resin (PA) is a polyarylate resin represented by the chemical formula (R-1) (hereinafter sometimes referred to as polyarylate resin (R-1)). In chemical formula (R-1), the number attached to the lower right of each repeating unit indicates the percentage (%) of the number of each repeating unit with respect to the total number of repeating units contained in the polyarylate resin. The total number of repeating units is the sum of the number of bisphenol-derived repeating units and the number of dicarboxylic acid-derived repeating units.

Polyarylate resins (PA) can be, for example, random copolymers, alternating copolymers, periodic copolymers, or block copolymers. In the polyarylate resin (PA), the arrangement of the repeating units is not particularly limited as long as the bisphenol-derived repeating units and the dicarboxylic acid-derived repeating units are adjacent and bound to each other. A bisphenol-derived repeating unit is, for example, repeating unit (10). The dicarboxylic acid-derived repeating unit is, for example, repeating unit (11).

The polyarylate resin (PA) may contain only repeating units (10) and (11) as repeating units. Alternatively, the polyarylate resin (PA) may further contain repeating units other than repeating units (10) and (11) as repeating units.

A method for producing the polyarylate resin (PA) is not particularly limited. Examples of a method for producing a polyarylate resin (PA) include a method of condensation polymerization of bisphenol for forming bisphenol-derived repeating units and dicarboxylic acid for forming dicarboxylic acid-derived repeating units. For polycondensation, known synthesis methods (eg, solution polymerization, melt polymerization, or interfacial polymerization) can be employed.

A bisphenol for constituting a bisphenol-derived repeating unit is, for example, a compound represented by general formula (BP-10). A dicarboxylic acid for constituting a dicarboxylic acid-derived repeating unit is, for example, a compound represented by the chemical formula (DC-11). R ¹¹ , R ¹² , W and X in general formulas (BP-10) and (DC-11) are respectively R ¹¹ , R 12 , W and X in general formulas ( ¹⁰ ) and (11) is synonymous with

A bisphenol for forming a bisphenol-derived repeating unit may be used after being derivatized to an aromatic diacetate. A dicarboxylic acid for forming a dicarboxylic acid-derived repeating unit may be used after being derivatized. Examples of derivatives of dicarboxylic acids include dicarboxylic acid dichlorides, dicarboxylic acid dimethyl esters, dicarboxylic acid diethyl esters, and dicarboxylic acid anhydrides. A dicarboxylic acid dichloride is a compound in which two “—C(=O)—OH” groups of a dicarboxylic acid are each substituted with a “—C(=O)—Cl” group.

One or both of a base and a catalyst may be added in the polycondensation of bisphenol and dicarboxylic acid. Examples of bases include sodium hydroxide. Examples of catalysts include benzyltributylammonium chloride, ammonium chloride, ammonium bromide, quaternary ammonium salts, triethylamine, and trimethylamine. The polyarylate resin has been described above.

Next, the polycarbonate resin will be described. Examples of polycarbonate resins include bisphenol ZC-type polycarbonate resins, bisphenol C-type polycarbonate resins, bisphenol A-type polycarbonate resins, and bisphenol Z-type polycarbonate resins. A bisphenol Z-type polycarbonate resin has a repeating unit represented by the chemical formula (R-2). Hereinafter, a polycarbonate resin having a repeating unit represented by the chemical formula (R-2) may be referred to as a polycarbonate resin (R-2). The polycarbonate resin has been described above.

(Additive)
Additives include, for example, ultraviolet absorbers, antioxidants, radical scavengers, singlet quenchers, softeners, surface modifiers, extenders, thickeners, dispersion stabilizers, waxes, donors, surface active agents, plasticizers, sensitizers, electron acceptor compounds, and leveling agents.

(combination of materials)
In order to improve the crack resistance of the photoreceptor and suppress crystallization, the combination of the hole transport agents (1) and (2) and the electron transport agent is selected from combination No. 1 shown in Table 1. Each of F-1 to F-8 is preferred. For the same reason, the combination of the hole transport agents (1) and (2) and the electron transport agent is the combination No. 1 shown in Table 1. It is each of F-1 to F-8, and the charge generating agent is more preferably Y-type titanyl phthalocyanine.

In order to improve the crack resistance of the photoreceptor and suppress the crystallization, the combination of the hole transport agents (1) and (2), the electron transport agent, and the binder resin is selected from combination No. 1 shown in Table 2. Each of G-1 to G-17 is preferred. For the same reason, the combination of the hole transport agents (1) and (2), the electron transport agent, and the binder resin is the combination No. shown in Table 2. Each of G-1 to G-17, and the charge generating agent is more preferably Y-type titanyl phthalocyanine.

In Tables 1 and 2 above, "No." "HTM(1)" indicates hole transport agent (1), "HTM(2)" indicates hole transport agent (2), "ETM" indicates electron transport agent, and "resin" indicates a binder resin. "I" in the "Resin" column indicates polyarylate resin (I). "R-1" in the "Resin" column indicates polyarylate resin (R-1). "R-2" in the "Resin" column indicates polycarbonate resin (R-2).

(Conductive substrate)
The conductive substrate is not particularly limited as long as it can be used as the conductive substrate of the photoreceptor. At least the surface portion of the conductive substrate may be made of a conductive material. An example of the conductive substrate is a conductive substrate made of a conductive material. Another example of a conductive substrate is a conductive substrate coated with a material having electrical conductivity. Conductive materials include, for example, aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, and brass. These conductive materials may be used alone, or two or more of them may be used in combination (for example, as an alloy). Among these electrically conductive materials, aluminum and aluminum alloys are preferred because of good charge transfer from the photosensitive layer to the conductive substrate.

The shape of the conductive substrate is appropriately selected according to the structure of the image forming apparatus. Examples of the shape of the conductive substrate include a sheet shape and a drum shape. Moreover, the thickness of the conductive substrate is appropriately selected according to the shape of the conductive substrate.

(middle layer)
The intermediate layer (undercoat layer) contains, for example, inorganic particles and a resin used for the intermediate layer (intermediate layer resin). The presence of the intermediate layer makes it possible to maintain an insulating state to the extent that leakage can be suppressed, and to smooth the flow of current generated when the photosensitive member is exposed to light, thereby suppressing an increase in resistance.

Examples of inorganic particles include particles of metals (e.g., aluminum, iron, and copper), particles of metal oxides (e.g., titanium oxide, alumina, zirconium oxide, tin oxide, and zinc oxide), and non-metal oxides. (eg, silica) particles. One of these inorganic particles may be used alone, or two or more thereof may be used in combination.

Examples of the intermediate layer resin are the same as those of the binder resin already described. In order to form the intermediate layer and the photosensitive layer satisfactorily, the resin for the intermediate layer is preferably different from the binder resin contained in the photosensitive layer. The intermediate layer may contain additives. Examples of additives contained in the intermediate layer are the same as examples of additives contained in the photosensitive layer.

<Method for manufacturing photoreceptor>
The photoreceptor manufacturing method includes a hole transport agent manufacturing step and a photosensitive layer forming step.

(Hole transport agent manufacturing process)
A hole transport agent is manufactured in the hole transport agent manufacturing process. The hole transport agent manufacturing process includes a first stirring process and a second stirring process. In the first stirring step, the mixed liquid (hereinafter sometimes simply referred to as "liquid") is first stirred. The liquid contains a compound represented by general formula (A) and a compound represented by general formula (B). In the second stirring step, the compound represented by the general formula (C) is further added to the liquid obtained in the first stirring step, and the liquid is subjected to second stirring. The second stirring step is carried out without purifying the liquid after the first stirring step. A hole transport agent containing both a first hole transport agent and a second hole transport agent (i.e., a mixture of hole transport agents (1) and (2)) through a first stirring step and a second stirring step is obtained. The resulting mixture of hole transport agents (1) and (2) is used as a hole transport agent in the step of forming a photosensitive layer. Hereinafter, the compounds represented by general formulas (A), (B) and (C) may be referred to as compounds (A), (B) and (C), respectively.

R ¹ , R ² , R ³ , R ⁴ and R ⁵ in general formula (A) are respectively the same as R ^1A , R ^2A , R ^3A , R ^4A and R ^5A in general formula (1) represents the group of R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ in general formula (B) are respectively the same as R ^6A , R ^7A , R ^8A , R ^9A and R ^10A in general formula (1) represents the group of Z ¹ in general formula (B) represents a halogen atom. Y in general formula (C) represents the same group as Y in general formula (1). Z ² and Z ³ in general formula (C) represent halogen atoms.

As represented by the following reaction formula (r-1), 1 molar equivalent of the compound (A) reacts with 2 molar equivalents of the compound (B) to obtain 1 molar equivalent of the hole transport agent (2 ) is obtained. In the first stirring step, the reaction represented by reaction formula (r-1) proceeds. The reaction represented by the reaction formula (r-1) may proceed not only in the first stirring step but also in the second stirring step.

Further, as represented by the following reaction formulas (r-2) and (r-3), 2 molar equivalents of compound (A), 2 molar equivalents of compound (B), and 1 molar equivalent of compound (C ) gives 1 molar equivalent of hole transport agent (1). Specifically, as represented by reaction formula (r-2), 2 molar equivalents of compound (A) and 2 molar equivalents of compound (B) are reacted to give 2 molar equivalents of chemical formula (D). A compound represented by (hereinafter sometimes referred to as compound (D)) is obtained. Compound (D) is an intermediate product. Then, as represented by the reaction formula (r-3), 2 molar equivalents of the compound (D) and 1 molar equivalent of the compound (C) are reacted to obtain 1 molar equivalent of the hole transport agent ( 1) is obtained. In the first stirring step, the reaction represented by Reaction Formula (r-2) proceeds, and in the second stirring step, the reaction represented by Reaction Formula (r-3) proceeds. The reaction represented by the reaction formula (r-2) may proceed not only in the first stirring step but also in the second stirring step.

Since the raw materials of the hole transport agents (1) and (2) are common like the compound (A), R ¹ in the general formula (A) is the same as R ^1A in the general formula (1) and R It is the same group as ^1B and R ^1C in general formula (2). Similarly to R ¹ , R ² to R ⁵ in general formula (A) are the same groups as the corresponding substituents in general formulas (1) and (2). Since the raw materials of the hole transport agents (1) and (2) are common like the compound (B), R ⁶ in the general formula (B) corresponds to R ^6A and R ^6B in the general formula (1). , and the same group as R ^6C and R ^6D in general formula (2). Similarly to R ⁶ , R ⁷ to R ¹⁰ in general formula (B) are the same groups as the corresponding substituents in general formulas (1) and (2).

A palladium catalyst may be added to the first stirred liquid in the first stirring step and the second stirred liquid in the second stirring step. Palladium catalysts include, for example, palladium(II) acetate, palladium(II) chloride, sodium hexachloropalladium(IV) tetrahydrate, and tris(dibenzylideneacetone)dipalladium(0).

A ligand may be added to the liquid to be first stirred in the first stirring step and the liquid to be second stirred in the second stirring step. Examples of ligands include 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl, (4-dimethylaminophenyl)di-tertbutylphosphine, tricyclohexylphosphine, triphenylphosphine, and methyl Diphenylphosphine can be mentioned.

A base may be added to the liquid to be first stirred in the first stirring step and the liquid to be second stirred in the second stirring step. Bases include, for example, sodium tert-butoxide, tripotassium phosphate, and cesium fluoride.

A solvent may be added to the liquid to be first stirred in the first stirring step and the liquid to be second stirred in the second stirring step. Solvents include, for example, xylene, toluene, tetrahydrofuran, and dimethylformamide.

The temperature of the liquid to be first stirred in the first stirring step and the temperature of the liquid to be second stirred in the second stirring step is preferably 80° C. or higher and 140° C. or lower. The first stirring time is preferably 1 hour or more and 10 hours or less, more preferably 5 hours or more and 10 hours or less. The second stirring time is preferably 1 hour or more and 10 hours or less, more preferably 1 hour or more and 4 hours or less. The first stirring and the second stirring may be performed under an atmosphere of inert gas (for example, nitrogen gas or argon gas).

In the hole transport agent manufacturing process, the liquid is not purified after the first stirring process. Therefore, the manufacturing process of the hole transport agent can be simplified. Also, through the first stirring step and the second stirring step, the hole transport agents (1) and (2) are simultaneously obtained in the form of a mixture. Since it is obtained in the form of a mixture, it is possible to omit the operation of weighing and mixing the hole transport agents (1) and (2) when preparing the coating solution in the photosensitive layer forming step.

In the hole transport agent production step, the hole transport agent (2) remains in the hole transport agent obtained in the second stirring step. By deliberately leaving the hole transporting agent (2) without completely removing the hole transporting agent (2), which is a by-product, both the hole transporting agents (1) and (2) are transferred to the photosensitive layer. can be contained in Therefore, the crack resistance of the photoreceptor can be improved, and crystallization of the photoreceptor can be suppressed. In addition, purification may be performed after the second stirring step so that the hole transport agent (2) is not completely removed. Further, purification may be performed after the second stirring step so that the hole transport agent (1) is not completely removed. Purification methods after the second stirring step include, for example, activated clay treatment, recrystallization, and combinations thereof.

The content of the hole transport agent (2) with respect to the total mass of the hole transport agents (1) and (2) is, for example, the ratio of the amount of the compound (B) added to the amount of the compound (A) added ( B/A) can be adjusted. A ratio (B/A) is a molar ratio conversion value. The higher the ratio (B/A), the higher the content of hole transport agent (2) relative to the total mass of hole transport agents (1) and (2). The ratio (B/A) is preferably 1.05 or more and 1.45 or less, more preferably 1.05 or more and 1.25 or less.

Further, the content of the hole transport agent (2) with respect to the total mass of the hole transport agents (1) and (2) is, for example, the additive substance amount of the compound (A) with respect to the additive substance amount of the compound (C) It can be adjusted by changing the volume ratio (A/C). A ratio (A/C) is a molar ratio conversion value. The higher the ratio (A/C), the higher the content of hole transport agent (2) relative to the total mass of hole transport agents (1) and (2). The ratio (A/C) is preferably 2.30 or more and 3.30 or less, more preferably 2.30 or more and 2.60 or less.

Moreover, the content of the hole transport agent (2) with respect to the total mass of the hole transport agents (1) and (2) is, for example, It can be adjusted by performing subsequent purification and changing the purification conditions. In order to adjust the content of the hole transport agent (2) with respect to the total mass of the hole transport agents (1) and (2), the hole transport agent obtained through the first stirring step and the second stirring step One or both of hole transport agents (1) and (2) may be further added to the agent.

(Photosensitive layer forming step)
In the photosensitive layer forming step, a coating liquid (more specifically, a coating liquid for forming a photosensitive layer) is applied onto the conductive substrate, and at least part of the solvent contained in the coating liquid is removed to form the photosensitive layer. The coating liquid contains a charge generating agent, a hole transporting agent, an electron transporting agent, a binder resin and a solvent.

The solvent contained in the coating liquid is not particularly limited as long as it can dissolve or disperse each component contained in the coating liquid. Examples of solvents include alcohols (more specifically, methanol, ethanol, isopropanol, butanol, etc.), aliphatic hydrocarbons (more specifically, n-hexane, octane, cyclohexane, etc.), aromatic hydrocarbons, etc. Hydrogen (more specifically, benzene, toluene, xylene, etc.), halogenated hydrocarbons (more specifically, dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene, etc.), ethers (more specifically, dimethyl ether , diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether), ketones (more specifically, acetone, methyl ethyl ketone, cyclohexanone, etc.), esters (more specifically, ethyl acetate, methyl acetate, etc.), Dimethylformaldehyde, dimethylformamide, and dimethylsulfoxide. These solvents may be used singly or in combination of two or more.

The coating liquid is prepared by dissolving or dispersing a charge generating agent, a hole transporting agent, an electron transporting agent and a binder resin in a solvent. For dissolution or dispersion, for example, a bead mill, roll mill, ball mill, attritor, paint shaker, or ultrasonic disperser can be used.

Examples of methods for applying the coating liquid include dip coating, spray coating, spin coating, and bar coating.

Methods for removing at least part of the solvent contained in the coating liquid include, for example, heating, reduced pressure, and combined use of heating and reduced pressure. More specifically, a method of heat-treating (hot-air drying) using a high-temperature dryer or a reduced-pressure dryer is exemplified. The heat treatment temperature is, for example, 40° C. or higher and 150° C. or lower. The heat treatment time is, for example, 3 minutes or more and 120 minutes or less.

The photoreceptor manufacturing method may further include a step of forming an intermediate layer and a protective layer, if necessary. A known method can be appropriately selected for the step of forming the intermediate layer and the protective layer.

<Image forming apparatus>
Next, an image forming apparatus including the photoreceptor 1 of this embodiment will be described. A tandem color image forming apparatus will be described below as an example with reference to FIG. FIG. 4 is a cross-sectional view showing an example of an image forming apparatus.

The image forming apparatus 100 shown in FIG. 4 includes image forming units 40a, 40b, 40c, and 40d, a transfer belt 50, and a fixing device . Hereinafter, each of the image forming units 40a, 40b, 40c, and 40d will be referred to as the image forming unit 40 when there is no need to distinguish between them.

The image forming unit 40 includes an image carrier 30 , a charging device 42 , an exposure device 44 , a developing device 46 , a transfer device 48 and a cleaning member 52 . The image carrier 30 is the photoreceptor 1 of this embodiment.

As described above, since the photoreceptor 1 of the present embodiment is excellent in crack resistance, the durability of the image forming apparatus 100 can be improved by providing such a photoreceptor 1 as the image carrier 30 . Further, as already described, since the photoreceptor 1 of the present embodiment can suppress crystallization, the image forming apparatus 100 can form a good image by using the photoreceptor 1 as the image carrier 30 .

An image carrier 30 is provided at a central position of the image forming unit 40 . The image carrier 30 is rotatable in the arrow direction (counterclockwise). Around the image carrier 30 , there are a charging device 42 , an exposure device 44 , a developing device 46 , a transfer device 48 , and a cleaning member 52 in the order described from the upstream side in the rotational direction of the image carrier 30 . be provided.

Each of the image forming units 40a to 40d sequentially superimposes toner images of a plurality of colors (for example, four colors of black, cyan, magenta, and yellow) on the recording medium P on the transfer belt 50. FIG.

The charging device 42 charges the surface (for example, the peripheral surface) of the image carrier 30 to a positive polarity, for example. The charging device 42 is, for example, a charging roller.

The exposure device 44 exposes the charged surface of the image carrier 30 . Thereby, an electrostatic latent image is formed on the surface of the image carrier 30 . The electrostatic latent image is formed based on image data input to image forming apparatus 100 .

The developing device 46 supplies toner to the surface of the image carrier 30 and develops the electrostatic latent image into a toner image. When the developing device 46 develops the electrostatic latent image into a toner image, the surface of the image carrier 30 is in contact with the surface (for example, the peripheral surface) of the developing device 46 . That is, the image forming apparatus 100 employs the contact development method. The developing device 46 is, for example, a developing roller. When the developer is a one-component developer, the developing device 46 supplies toner, which is a one-component developer, to the electrostatic latent image formed on the image carrier 30 . When the developer is a two-component developer, the developing device 46 supplies the electrostatic latent image formed on the image carrier 30 with toner, which is contained in the two-component developer and carrier. In this manner, the image carrier 30 carries a toner image.

The transfer belt 50 conveys the recording medium P between the image carrier 30 and the transfer device 48 . The transfer belt 50 is an endless belt. The transfer belt 50 is rotatable in the arrow direction (clockwise).

The transfer device 48 transfers the toner image developed by the developing device 46 from the surface of the image carrier 30 to a transfer receiving body. The object to be transferred is the recording medium P. As shown in FIG. Specifically, the transfer device 48 transfers the toner image from the surface of the image carrier 30 to the recording medium P while the recording medium P is in contact with the surface of the image carrier 30 . That is, the image forming apparatus 100 employs a direct transfer method. The transfer device 48 is, for example, a transfer roller.

The cleaning member 52 is brought into pressure contact with the surface of the image carrier 30 , and the cleaning member 52 collects the toner adhering to the peripheral surface of the image carrier 30 . The cleaning member 52 is, for example, a cleaning blade.

The recording medium P onto which the toner image has been transferred by the transfer device 48 is conveyed to the fixing device 54 by the transfer belt 50 . The fixing device 54 is, for example, a heating roller and/or a pressure roller. The unfixed toner image transferred by the transfer device 48 is heated and/or pressed by the fixing device 54 . The toner image is fixed on the recording medium P by heating and/or pressing the toner image. As a result, an image is formed on the recording medium P. FIG.

An example of the image forming apparatus has been described above, but the image forming apparatus is not limited to the image forming apparatus 100 described above. Although the image forming apparatus 100 is a color image forming apparatus, the image forming apparatus may be a monochrome image forming apparatus. In this case, the image forming apparatus may have, for example, only one image forming unit. Further, although the image forming apparatus 100 employs a tandem system, the image forming apparatus may employ, for example, a rotary system. Although the charging roller has been described as an example of the charging device 42, the charging device may be a charging device other than the charging roller (for example, a scorotron charger, a charging brush, or a corotron charger). Although the image forming apparatus 100 employs a contact developing method, the image forming apparatus may employ a non-contact developing method. Although the image forming apparatus 100 employs a direct transfer method, the image forming apparatus may employ an intermediate transfer method. When the image forming apparatus employs an intermediate transfer method, the transfer target corresponds to an intermediate transfer belt. Although the cleaning blade has been described as an example of the cleaning member 52, the cleaning member may be a cleaning roller. Although the image forming unit 40 does not include a static eliminating device, the image forming unit may further comprise a static eliminating device.

EXAMPLES Hereinafter, the present invention will be described more specifically using examples. However, the present invention is in no way limited to the scope of the examples.

First, as materials for forming the photosensitive layer of the photoreceptor, the following charge-generating agent, electron-transporting agent, hole-transporting agent, and binder resin were prepared.

(Charge generating agent)
Y-type titanyl phthalocyanine described in the embodiment was prepared as a charge generating agent.

(Electron transport agent)
Each of the electron transport agents (E-1), (E-2), and (E-3) described in the embodiment was prepared as the electron transport agent. In addition, a compound represented by the chemical formula (E-4) (hereinafter referred to as electron transport agent (E-4)) was prepared as an electron transport agent used in Comparative Examples.

(binder resin)
As binder resins, each of the polyarylate resin (R-1) and the polycarbonate resin (R-2) described in the embodiment was prepared. The viscosity average molecular weight of the polyarylate resin (R-1) was 47,500. The polycarbonate resin (R-2) had a viscosity average molecular weight of 50,000.

(Hole transport agent)
Samples (M-A1) to (M-A4), which are mixtures of hole transport agents (1) and (2), were synthesized by the method shown below. Samples (M-B1) to (M-B5) used in Comparative Examples were synthesized by the method shown below. Table 3 shows the compositions of samples (M-A1) to (M-A4) and (M-B1) to (M-B5). The terms in Table 3 are as follows. "HTM(1)" and "HTM(2)" in the "Type" column indicate the type of hole transport agent (1) and the type of hole transport agent (2), respectively. "HTM (1)" in the "Content" column is the content of the hole transport agent (1) with respect to the total mass of the hole transport agent (1) and the hole transport agent (2) (unit: mass%). indicates "HTM (2)" in the "Content" column is the content of the hole transport agent (2) with respect to the total mass of the hole transport agent (1) and the hole transport agent (2) (unit: % by mass). indicates "-" indicates that the corresponding hole transport agent was not contained in the sample.

In the explanation of the method for synthesizing each sample shown below, the compounds represented by the following chemical formulas (A-1) to (A-4), (B-1) to (B-2), and (C-1) are , respectively, may be described as compounds (A-1) to (A-4), (B-1) to (B-2), and (C-1).

(Preparation of sample (M-A1))
A sample (M-A1) was prepared according to the following reaction formula (ra).

Specifically, tris(dibenzylideneacetone)dipalladium (0.0366 g, 0.040 mmol) and 2-dicyclohexylphosphino-2′,4′,6′-triisopropyl were added to a 500 mL three-necked flask equipped with a still tube. Biphenyl (0.0763 g, 0.016 mmol) and sodium tert-butoxide (9.669 g, 100.7 mmol) were charged. The air in the flask was replaced with nitrogen gas by repeating degassing and nitrogen gas replacement in the flask twice.

Then, 2-ethylaniline (compound (A-1), 8.45 g, 69.8 mmol), 4-chlorotoluene (compound (B-1), 10.13 g, 80.0 mmol) and xylene (45 g) was added into the flask. The temperature of the liquid in the flask was raised to 130° C. so that the liquid in the flask was refluxed. The temperature of the liquid was raised while tert-butanol generated during the temperature raising process was distilled off. While refluxing the liquid, the liquid was stirred at 130° C. for 2 hours (corresponding to the first stirring). The liquid in the flask was then cooled to 50°C.

Then, sodium tert-butoxide (7.680 g, 80.0 mmol), 4,4″-dibro-p-terphenyl (compound (C-1), 11.60 g, 30.0 mmol) and palladium acetate ( II) (0.0168 g, 0.075 mmol), 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl (0.1425 g, 0.299 mmol) and xylene (32 g) were placed in a flask. Added more to the liquid inside. The temperature of the liquid in the flask was raised to 130° C. so that the liquid in the flask was refluxed. The temperature of the liquid was raised while tert-butanol generated during the temperature raising process was distilled off. While refluxing the liquid, the liquid was stirred at 130° C. for 3 hours (corresponding to the second stirring).

The liquid in the flask was then cooled to 90°C. The 90° C. liquid in the flask was filtered to remove insoluble matter in the liquid to obtain a filtrate. The filtrate was treated twice with activated clay. The activated clay treatment was a treatment in which activated clay (“SA-1” manufactured by Japan Activated Clay Co., Ltd., 8 g) was added to the filtrate, stirred at 110° C. for 15 minutes, filtered again, and the filtrate was recovered. The filtrate that had been subjected to the activated clay treatment twice was concentrated under reduced pressure to obtain a concentrate. An amount of isohexane (about 50 g) was added to the concentrate to make the concentrate slightly cloudy, and then methanol (50 g) was added. The concentrate was cooled to 5°C, and the precipitated crystals were collected by filtration. Xylene (100 g) was added to the crystals and heated to 110° C. to dissolve the crystals in xylene to obtain a solution. The solution was subjected to the above activated clay treatment five times. The filtrate that had been treated with activated clay five times was concentrated under reduced pressure to obtain a concentrate. An amount of isohexane (about 50 g) was added to the concentrate to make the concentrate slightly cloudy, and then methanol (50 g) was added. The concentrate was cooled to 5°C, and the precipitated crystals were collected by filtration. The resulting crystals were dried under vacuum at 70° C. for 24 hours to obtain a sample (M-A1). Sample (M-A1) was a mixture containing a hole transport agent (HTM-1) and a hole transport agent (HTM-A). The yield of sample (M-A1) was 16.3 g. The yield of the hole transport agent (HTM-1) contained in the sample (M-A1) relative to the compound (C-1) was 84%.

(Preparation of sample (M-A2))
Sample (M-A2) was obtained in the same manner as sample (M-A1) except that 69.8 mmol of compound (A-1) was changed to 69.8 mmol of compound (A-2). Sample (M-A2) was a mixture containing a hole transport agent (HTM-2) and a hole transport agent (HTM-B).

(Preparation of sample (M-A3))
Sample (M-A3) was obtained in the same manner as sample (M-A1), except that 69.8 mmol of compound (A-1) was changed to 69.8 mmol of compound (A-3). Sample (M-A3) was a mixture containing a hole transport agent (HTM-3) and a hole transport agent (HTM-C).

(Preparation of sample (M-A4))
Except that the compound (A-1) 69.8 mmol was changed to the compound (A-4) 69.8 mmol, and the compound (B-1) 80.0 mmol was changed to the compound (B-2) 80.0 mmol , Sample (M-A4) was obtained in the same manner as the preparation of sample (M-A1). Sample (M-A4) was a mixture containing a hole transport agent (HTM-4) and a hole transport agent (HTM-D).

(Preparation of sample (M-B1))
The sample (M-A1) was purified by silica gel column chromatography using a mixed solvent of toluene and isohexane (50/50 by volume) as a developing solvent. Fractions containing the hole transport agent (HTM-1) were collected in this manner. The separated liquid (fraction) was concentrated under reduced pressure until it became slightly cloudy to obtain a concentrated liquid. Isohexane and methanol were added to the concentrate. The concentrate was cooled to 5° C., and the precipitated crystals were collected by filtration to obtain a sample (M-B1). Sample (M-B1) contained only hole transport agent (HTM-1) and no hole transport agent (HTM-A).

(Preparation of sample (M-B2))
Sample (M-B2) was obtained in the same manner as sample (M-B1) except that sample (M-A1) was changed to sample (M-A2). Sample (M-B2) contained only hole transport agent (HTM-2) and no hole transport agent (HTM-B).

(Preparation of sample (M-B3))
A sample (M-B3) was obtained in the same manner as the sample (M-B1) except that the sample (M-A1) was changed to the sample (M-A3). Sample (M-B3) contained only hole transport agent (HTM-3) and no hole transport agent (HTM-C).

(Preparation of sample (M-B4))
Sample (M-B4) was obtained in the same manner as sample (M-B1) except that sample (M-A1) was changed to sample (M-A4). Sample (M-B4) contained only hole transport agent (HTM-4) and no hole transport agent (HTM-D).

(Preparation of sample (M-B5))
The sample (M-A1) was purified by silica gel column chromatography using a mixed solvent of toluene and isohexane (50/50 by volume) as a developing solvent. Fractions containing the hole transport agent (HTM-A) were collected in this manner. The separated liquid (fraction) was concentrated under reduced pressure until it became slightly cloudy to obtain a concentrated liquid. Isohexane and methanol were added to the concentrate. The concentrate was cooled to 5° C. and the precipitated crystals were collected by filtration to obtain a sample (M-B5). Sample (M-B5) contained only hole transport agent (HTM-A) and no hole transport agent (HTM-1).

(Measurement of content of hole transport agent (1) and hole transport agent (2))
For each prepared sample, the content of hole transport agent (1) with respect to the total mass of hole transport agent (1) and hole transport agent (2) was measured. As the content rate of the hole transport agent (1), the content rates of the hole transport agents (HTM-1) to (HTM-4) included in the general formula (1) were measured. In addition, the content of the hole transport agent (2) with respect to the total mass of the hole transport agent (1) and the hole transport agent (2) was measured for each prepared sample. As the content rate of the hole transport agent (2), the content rates of the hole transport agents (HTM-A) to (HTM-D) included in the general formula (2) were measured. The measuring method was as follows.

2.0 mg of the sample (more specifically, each of samples (M-A1) to (M-A4) and (M-B1) to (M-B5)) was dissolved in 670 mg of tetrahydrofuran to obtain a tetrahydrofuran solution. rice field. Tetrahydrofuran containing no stabilizer was used. The resulting tetrahydrofuran solution was analyzed by high performance liquid chromatography (HPLC). Specifically, the tetrahydrofuran solution of the sample was analyzed using the analysis equipment and analysis conditions shown below, and an HPLC chart was obtained. The content of the hole transport agent (1) in the sample was determined from the peak area of the hole transport agent (1) in the HPLC chart. The content of the hole transport agent (2) in the sample was obtained from the peak area of the hole transport agent (2) in the HPLC chart. From the determined content of hole transport agent (1) and the content of hole transport agent (2), the content of hole transport agent (1) and the content of hole transport agent (2) are calculated. bottom. The calculation results are shown in the "content rate" column of Table 3.

(Analytical equipment and analytical conditions)
・ Analyzer: "LaChrom ELITE" manufactured by Hitachi High-Technologies Co., Ltd.
・Detection wavelength: 254 nm
・ Column: "Inertsil (registered trademark) ODS-3" manufactured by GL Sciences Co., Ltd. (inner diameter: 4.6 mm, length: 250 mm)
・Column temperature: 40°C
・Developing solvent: acetonitrile ・Flow rate: 1 mL/min ・Sample injection volume: 1 μL

<Production of Photoreceptor>
Photoreceptors (PA-1) to (PA-9) and (PB-1) to (PB-10) were prepared using the charge generating agent, electron transport agent, hole transport agent, and binder resin prepared as described above. manufactured.

(Production of photoreceptor (PA-1))
3 parts by mass of Y-type titanyl phthalocyanine as a charge generating agent, 70 parts by mass of sample (M-A1) (specifically, 67 parts by mass of hole transport agent (HTM-1) and 3 parts by mass of hole transport agent (HTM-A) parts), 100 parts by mass of a polyarylate resin (R-1) as a binder resin, 30 parts by mass of an electron transport agent (E-1), and 800 parts by mass of tetrahydrofuran as a solvent are mixed using a ball mill for 50 hours. to obtain a coating liquid. The coating liquid was applied onto a conductive substrate (drum-shaped support made of aluminum) by a dip coating method. The applied coating liquid was dried with hot air at 120° C. for 60 minutes. Thus, a photosensitive layer (thickness: 28 μm) was formed on the conductive substrate to obtain a photosensitive member (PA-1). In photoreceptor (PA-1), a single photosensitive layer was provided directly on a conductive substrate.

(Production of photoreceptors (PA-2) to (PA-9) and (PB-1) to (PB-10))
Photoreceptors (PA-2) to (PA-9) and photoreceptors (PA-2) to (PA-9) were prepared in the same manner as photoreceptor (PA-1) except that the types of samples, electron transport agents, and binder resins shown in Table 4 were used. Each of (PB-1) to (PB-10) was produced.

<Evaluation>
For each of the photoreceptors (PA-1) to (PA-9) and (PB-1) to (PB-10) to be evaluated, the sensitivity characteristics, crack resistance, and crystal It was evaluated whether or not the transformation was suppressed.

<Evaluation of sensitivity characteristics>
The evaluation environment for the sensitivity characteristics of the photoreceptor was an environment with a temperature of 23° C. and a relative humidity of 50% RH. The surface of the photoreceptor was charged to +750 V using a drum sensitivity tester (manufactured by Gentec Co., Ltd.). Next, monochromatic light (wavelength: 780 nm, exposure amount: 0.7 μJ/cm ² ) was extracted from the light of the halogen lamp using a bandpass filter and irradiated onto the surface of the photoreceptor. The surface potential of the photoreceptor was measured 40 milliseconds after the end of irradiation with monochromatic light. The measured surface potential was taken as the post-exposure potential V _L (unit: +V) of the photosensitive member. Table 4 shows the post-exposure potential V _L of the photosensitive member. A photoreceptor having a post-exposure potential V _L of +150 V or less was evaluated as having good sensitivity characteristics.

<Evaluation of crack resistance>
The evaluation environment for the crack resistance of the photoreceptor was an environment with a temperature of 23° C. and a relative humidity of 50% RH. A region of the photosensitive member from the lower end to 40 mm was immersed in an isoparaffin-based hydrocarbon solvent ("Isopar L" manufactured by Exxon Mobil) for 24 hours. After immersion for 24 hours, the number of cracks generated on the surface of the photoreceptor was confirmed. From the number of cracks, crack resistance was evaluated according to the following criteria. Table 4 shows the evaluation results.
Evaluation A (particularly good): The number of cracks is 20 or less.
Evaluation B (Good): The number of cracks is 21 or more and 100 or less.
Evaluation C (defective): The number of cracks is 101 or more.

<Evaluation of crystallization suppression>
The entire area of the photosensitive layer of the photoreceptor was observed with the naked eye to confirm the presence or absence of a crystallized portion in the photosensitive layer. Based on the confirmation results, whether or not crystallization of the photoreceptor was suppressed was evaluated according to the following criteria. Table 4 shows the evaluation results.
Evaluation A (Good): No crystallized portion was observed.
Evaluation B (poor): A crystallized portion was confirmed.

Each term in Table 4 is as follows. "HTM" indicates hole transport agent. "HTM (1)" indicates hole transport agent (1). "HTM(2)" indicates hole transport agent (2). "ETM" indicates an electron transport agent. "Resin" indicates a binder resin. “V _L ” indicates the post-exposure potential. "Crack" indicates the evaluation result of the crack resistance of the photoreceptor. "Crystalization" indicates the evaluation result of whether or not crystallization of the photoreceptor is suppressed. "-" indicates that the corresponding component is not contained.

As shown in Table 4, the photosensitive layers of the photoreceptors (PA-1) to (PA-9) are single layers, and contain a charge-generating agent, a hole-transporting agent, an electron-transporting agent, and a binder resin. contained. The photosensitive layer contains two types of hole transport agents (1) and (2) as hole transport agents (more specifically, hole transport agents (HTM-1) and (HTM-A), hole transport agents (HTM-2) and (HTM-B), hole transport agents (HTM-3) and (HTM-C), or hole transport agents (HTM-4) and (HTM-D)). rice field. The photosensitive layer contains electron transport agents (10), (11), or (12) (more specifically, electron transport agents (E-1), (E-2), or (E- 3)) was contained. The crack resistance evaluation of photoreceptors (PA-1) to (PA-9) was A or B, and these photoreceptors were excellent in crack resistance. Photoreceptors (PA-1) to (PA-9) were evaluated as A for crystallization suppression, and crystallization of these photoreceptors was suppressed. In addition, the post-exposure potential V _L of the photoreceptors (PA-1) to (PA-9) is +150 V or less, and these photoreceptors improve crack resistance and suppress crystallization without impairing sensitivity characteristics. was able to achieve

From the above, it was shown that the photoreceptor according to the present invention has excellent crack resistance and can suppress crystallization. Further, since the photoreceptor according to the present invention is excellent in crack resistance and can suppress crystallization, it is judged that an image forming apparatus provided with such a photoreceptor is excellent in durability and capable of forming good images. It was also shown that the method for producing a photoreceptor according to the present invention can produce a photoreceptor that is excellent in crack resistance and capable of suppressing crystallization while simplifying the manufacturing process of the hole transport agent.

A photoreceptor according to the present invention can be used in an image forming apparatus. The image forming apparatus according to the present invention can be used to form an image on a recording medium. A photoreceptor manufactured by the manufacturing method according to the present invention can be used in an image forming apparatus.

1: photoreceptor (electrophotographic photoreceptor)
2: Conductive substrate 3: Photosensitive layer 30: Image carrier 42: Charging device 44: Exposure device 46: Developing device 48: Transfer device 100: Image forming device P: Recording medium

Claims (11)

comprising a conductive substrate and a photosensitive layer;
The photosensitive layer is a single layer,
The photosensitive layer contains a charge generating agent, a hole transport agent, an electron transport agent, and a binder resin,
the hole transport agent comprises a first hole transport agent and a second hole transport agent;
The first hole transport agent is a compound represented by the chemical formula (HTM-1), and the second hole transport agent is a compound represented by the chemical formula (HTM-A),
The first hole transport agent is a compound represented by the chemical formula (HTM-2), and the second hole transport agent is a compound represented by the chemical formula (HTM-B), or
The first hole transport agent is a compound represented by the chemical formula (HTM-3), and the second hole transport agent is a compound represented by the chemical formula (HTM-C),
The electron transport agent contains a compound represented by the chemical formula (E-1) ,
The electrophotographic photoreceptor, wherein the binder resin includes a polyarylate resin containing repeating units represented by chemical formulas (10-2), (11-X1), and (11-X3).

2. The electrophotographic photoreceptor according to claim 1 , wherein said photosensitive layer is provided as an outermost layer. an image carrier;
a charging device that positively charges the surface of the image carrier;
an exposure device that exposes the charged surface of the image carrier to form an electrostatic latent image on the surface of the image carrier;
a developing device that develops the electrostatic latent image as a toner image;
a transfer device for transferring the toner image from the image carrier to a transfer target;
An image forming apparatus, wherein the image carrier is the electrophotographic photosensitive member according to claim 1 or 2 . The transfer-receiving material is a recording medium,
4. The image forming apparatus according to claim 3, wherein said transfer device transfers said toner image from said image carrier to said recording medium while said recording medium is in contact with said surface of said image carrier. 5. The image forming apparatus according to claim 3 , wherein said surface of said image carrier is in contact with said developing device. The image forming apparatus according to any one of claims 3 to 5 , wherein the charging device is a charging roller. comprising a conductive substrate and a photosensitive layer;
The photosensitive layer is a single layer,
The photosensitive layer contains a charge generating agent, a hole transport agent, an electron transport agent, and a binder resin,
The hole-transporting agent includes a first hole-transporting agent and a second hole-transporting agent, the first hole-transporting agent being a compound represented by the general formula (1), and the second hole-transporting agent The transport agent is a compound represented by the general formula (2),
A method for producing an electrophotographic photoreceptor, wherein the electron transport agent contains a compound represented by general formula (10), (11), or (12),
a hole transport agent manufacturing step for manufacturing the hole transport agent;
A coating liquid containing the charge generating agent, the hole transporting agent, the electron transporting agent, the binder resin, and the solvent is applied onto the conductive substrate, and at least part of the solvent contained in the coating liquid is applied. and a photosensitive layer forming step of removing the photosensitive layer to form the photosensitive layer,
The hole transport agent manufacturing step includes a first stirring step and a second stirring step,
In the first stirring step, the mixed liquid containing the compound represented by the general formula (A) and the compound represented by the general formula (B) is first stirred,
In the second stirring step, the compound represented by the general formula (C) is further added to the mixed liquid, and the mixed liquid is second stirred,
The second stirring step is performed without purifying the mixed solution after the first stirring step,
A method for producing an electrophotographic photoreceptor, wherein the hole transport agent containing the first hole transport agent and the second hole transport agent is obtained through the first stirring step and the second stirring step.

(In general formula (1), R ^{1A ,} R ^2A , R ^3A , R ^4A , R 5A , R ^6A , R ^7A , R ^8A , R ^9A , and R ^10A each independently represent a hydrogen atom, a carbon atom, represents an alkyl group having a number of 1 to 8, an alkoxy group having 1 to 8 carbon atoms, or an aryl group having 6 to 14 carbon atoms,
R ^1B in the general formula (1) and R ^1C in the general formula (2) represent the same group as R ^1A in the general formula (1) ,
R ^2B in the general formula (1) and R ^2C in the general formula (2) represent the same group as R ^2A in the general formula (1) ,
R ^3B in the general formula (1) and R ^3C in the general formula (2) represent the same group as R ^3A in the general formula (1) ,
R ^4B in the general formula (1) and R ^4C in the general formula (2) represent the same group as R ^4A in the general formula (1) ,
R ^5B in the general formula (1) and R ^5C in the general formula (2) represent the same group as R ^5A in the general formula (1) ,
R ^6B in the general formula (1) and R ^6C and R ^6D in the general formula (2) represent the same groups as R ^6A in the general formula (1) ,
R ^7B in the general formula (1) and R ^7C and R ^7D in the general formula (2) represent the same groups as R ^7A in the general formula (1) ,
R ^8B in the general formula (1) and R ^8C and R ^8D in the general formula (2) represent the same groups as R ^8A in the general formula (1) ,
R ^9B in the general formula (1) and R ^9C and R ^9D in the general formula (2) represent the same groups as R ^9A in the general formula (1) ,
R ^10B in the general formula (1) and R ^10C and R ^10D in the general formula (2) represent the same group as R ^10A in the general formula (1) ,
Y in the general formula (1) represents a divalent group represented by the chemical formula (Y2). )

(In the general formula (10), Q ^5A and Q ^5B 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. , Q ^6A and Q ^6B each independently represent an alkyl group having 1 to 8 carbon atoms, a phenyl group, or an alkoxy group having 1 to 8 carbon atoms, and m 1 and _m 2 _each independently , represents an integer from 0 to 4,
In the general formula (11), Q7 ^and Q8 ^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; Q ⁹ represents an alkyl group having 1 to 8 carbon atoms, a phenyl group, or an alkoxy group having 1 to 8 carbon atoms, m 3 represents an integer of ₀ to 4,
In general formula (12), Q ¹⁰ and Q ¹¹ each independently represent an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, and Q ¹² represents a halogen atom or a hydrogen atom. )

(R ¹ , R ² , R ³ , R ⁴ and R ⁵ in the general formula (A) are respectively R ^1A , R ^2A , R ^3A , R ^4A and R in the general formula (1) represents the same group as ^5A ,
R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ in general formula (B) are respectively R ^6A , R ^7A , R ^8A , R ^9A and R ^10A in general formula (1) represents the same group as, Z ¹ in the general formula (B) represents a halogen atom,
Y in the general formula (C) represents the same group as Y in the general formula (1), and Z ² and Z ³ in the general formula (C) represent halogen atoms. ) The compound represented by the general formula (1) is a compound represented by the chemical formula (HTM-1), and the compound represented by the general formula (2) is represented by the chemical formula (HTM-A) is a compound that
The compound represented by the general formula (1) is a compound represented by the chemical formula (HTM-2), and the compound represented by the general formula (2) is represented by the chemical formula (HTM-B) is a compound that
The compound represented by the general formula (1) is a compound represented by the chemical formula (HTM-3), and the compound represented by the general formula (2) is represented by the chemical formula (HTM-C) or
The compound represented by the general formula (1) is a compound represented by the chemical formula (HTM-4), and the compound represented by the general formula (2) is represented by the chemical formula (HTM-D) 8. The method for producing an electrophotographic photoreceptor according to claim 7, wherein the compound is

The compound represented by the general formula (10) is a compound represented by the chemical formula (E-1),
The compound represented by the general formula (11) is a compound represented by the chemical formula (E-2),
9. The method for producing an electrophotographic photoreceptor according to claim 7, wherein the compound represented by general formula (12) is a compound represented by chemical formula (E-3).

The binder resin includes a polyarylate resin,
Any one of claims 7 to 9, wherein the polyarylate resin comprises at least one type of repeating unit represented by general formula (10) and at least one type of repeating unit represented by general formula (11). 1. The method for producing the electrophotographic photoreceptor according to item 1.

(In the general formula (10), R ¹¹ and R ¹² each independently represents a hydrogen atom or a methyl group, W represents a divalent group represented by general formula (W1), general formula (W2), or chemical formula (W3),
In general formula (11), X represents a divalent group represented by chemical formula (X1), chemical formula (X2), or chemical formula (X3). )

(In the general formula (W1), R ¹³ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ¹⁴ represents an alkyl group having 1 to 4 carbon atoms,
In the general formula (W2), t represents an integer of 1 or more and 3 or less. )

The electrophotographic photoreceptor according to claim 10, wherein the polyarylate resin is a polyarylate resin containing repeating units represented by chemical formulas (10-2), (11-X1), and (11-X3). Production method.

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