JP6569597B2 - Electrophotographic photosensitive member and method for manufacturing the same, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member and a method for manufacturing the same, a process cartridge, and an image forming apparatus.

  The electrophotographic photosensitive member is used in an electrophotographic image forming apparatus. The electrophotographic photoreceptor includes a photosensitive layer. The photosensitive layer contains, for example, a charge generating agent, a charge transporting agent (more specifically, a hole transporting agent or an electron transporting agent), and a resin (binder resin) for binding them. The photosensitive layer may contain a charge generation agent and a charge transport agent in the same layer, and may have both functions of charge generation and charge transport in the same layer. Such an electrophotographic photoreceptor is referred to as a single layer type electrophotographic photoreceptor.

  Patent Document 1 describes an organic photoelectric conversion film. An organic photoelectric conversion film is used for an optical sensor or a solar cell, for example. The organic photoelectric conversion film includes a p-type material layer and an n-type material layer. The n-type material layer is formed from 1,4,5,8-naphthalenetetracarboxylic dianhydride.

JP 2009-290190 A

  However, with the technique described in Patent Document 1, it has not been possible to sufficiently suppress the occurrence of black spots in an image and a decrease in toner image transferability.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrophotographic photosensitive member that suppresses the occurrence of black spots in an image and suppresses a decrease in transferability of a toner image, and a method for manufacturing the same. is there. Another object of the present invention is to provide a process cartridge and an image forming apparatus that suppress image defects (for example, image defects caused by occurrence of black spots in images and deterioration in toner image transferability).

  The electrophotographic photosensitive member of the present invention includes a conductive substrate and a photosensitive layer provided directly on the conductive substrate. The conductive substrate has an oxide film. The thickness of the oxide film is not less than 1 μm and not more than 25 μm. The photosensitive layer is a single-layer type photosensitive layer. The photosensitive layer includes a charge generating agent, a hole transport agent, tetracarboxylic dianhydride, and a binder resin. The tetracarboxylic dianhydride is one or more compounds selected from the group consisting of compounds represented by the general formulas (1), (2), and (3). Content of the said tetracarboxylic dianhydride is 0.02 mass part or more and 7.00 mass part or less with respect to 100 mass parts of said binder resins.

In the general formulas (1), (2), and (3), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or 6 to 14 carbon atoms. Represents an aryl group. The alkoxy group may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom. The alkyl group may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom. The aryl group may have one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen atom.

The method for producing an electrophotographic photoreceptor of the present invention is a method for producing the above-described electrophotographic photoreceptor. The method for producing an electrophotographic photosensitive member includes a photosensitive layer forming step and an oxide film forming step. In the oxide film forming step, the substrate is immersed in the water, taken out from the water and heated to form the oxide film on the surface of the substrate. The substrate includes aluminum or an aluminum alloy. In the photosensitive layer forming step, a photosensitive layer forming coating solution is applied onto the conductive substrate, and at least a part of the solvent contained in the applied photosensitive layer forming coating solution is removed to form the photosensitive layer. The coating solution for forming a photosensitive layer contains the charge generating agent, the hole transport agent, the tetracarboxylic dianhydride, the binder resin, and the solvent. The water has a volume resistivity of 1.0 × 10 ⁶ Ω · cm or more. The temperature of the water is 70 ° C. or higher and lower than 80 ° C. The time for immersing the substrate in the water is not less than 60 seconds and not more than 90 seconds. The heating is performed at a heating temperature of 110 ° C. or higher and 150 ° C. or lower.

  The process cartridge of the present invention includes the above-described electrophotographic photosensitive member.

  The image forming apparatus of the present invention includes an image carrier, a charging unit, an exposure unit, a developing unit, and a transfer unit. The charging unit charges the surface of the image carrier. The exposure unit exposes the charged surface of the image carrier to form an electrostatic latent image on the surface of the image carrier. The developing unit develops the electrostatic latent image as a toner image. The transfer unit transfers the toner image from the image carrier to a transfer body. The charging polarity of the charging unit is positive. The image carrier is the above-described electrophotographic photosensitive member.

  According to the electrophotographic photosensitive member of the present invention, it is possible to suppress the occurrence of black spots in an image and to suppress a decrease in toner image transferability. Further, according to the method for producing an electrophotographic photosensitive member of the present invention, it is possible to produce an electrophotographic photosensitive member that suppresses the occurrence of black spots in an image and suppresses a decrease in transferability of a toner image. In addition, according to the process cartridge and the image forming apparatus of the present invention, it is possible to suppress image defects.

(A), (b), and (c) are schematic sectional drawings which show the structure of the electrophotographic photosensitive member according to the first embodiment. It is a schematic diagram which shows the image which image defect generate | occur | produced. It is the schematic which shows the structure of the one aspect | mode of the image forming apparatus which concerns on 3rd embodiment. It is a schematic diagram which shows the image for evaluation.

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

  Hereinafter, a compound and its derivatives may be generically named by adding “system” after the compound name. In addition, when “polymer” is added after the compound name to indicate the polymer name, it means that the repeating unit of the polymer is derived from the compound or a derivative thereof.

  Hereinafter, unless otherwise specified, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an aryl group having 6 to 14 carbon atoms are as follows. Meaning.

  As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom is mentioned, for example.

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

  The alkoxy group having 1 to 6 carbon atoms is linear or branched and unsubstituted. Examples of the alkoxy group having 1 to 6 carbon atoms include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, n-pentoxy group, A tert-pentoxy group or an n-hexoxy group can be mentioned.

  An aryl group having 6 to 14 carbon atoms is unsubstituted. Examples of the aryl group having 6 to 14 carbon atoms include, for example, an unsubstituted aromatic monocyclic hydrocarbon group having 6 to 14 carbon atoms, and an unsubstituted aromatic condensed bicycle having 6 to 14 carbon atoms. It is a hydrocarbon group or an unsubstituted aromatic condensed tricyclic hydrocarbon group having 6 to 14 carbon atoms. Examples of the aryl group having 6 to 14 carbon atoms include a phenyl group, a naphthyl group, an anthryl group, and a phenanthryl group.

<First embodiment: electrophotographic photoreceptor>
The first embodiment relates to an electrophotographic photoreceptor (hereinafter sometimes referred to as “photoreceptor”). The photoconductor according to the first embodiment suppresses the generation of black spots in the image and suppresses the decrease in transferability of the toner image. The reason is presumed as follows.

  First, for the sake of convenience, a decrease in toner image transferability will be described. An electrophotographic image forming apparatus includes, for example, an image carrier (photosensitive member), a charging unit, an exposure unit, a developing unit, and a transfer unit. The transfer unit transfers the toner image from the photosensitive member to the transfer member. In the transfer process executed by the transfer unit, when the photosensitive member has a single-layer type photosensitive layer and the charged polarity of the photosensitive member is positive, the surface potential of the exposed region of the photosensitive member is lowered and becomes less than 0V. is there. As described above, when the surface potential of the exposure area of the photoconductor is less than 0 V, the transferability of the toner image from the photoconductor to the transfer body tends to be lowered. Such a drop in toner image transferability is likely to occur particularly in a high humidity environment (for example, relative humidity 80% RH).

  In the photoreceptor according to the first embodiment, the conductive substrate has an oxide film, and the thickness of the oxide film is 1 μm or more and 25 μm or less. The photosensitive layer contains tetracarboxylic dianhydride, and the tetracarboxylic dianhydride is selected from the group consisting of compounds represented by the general formulas (1), (2), and (3). These compounds. The content of tetracarboxylic dianhydride is 0.02 parts by mass or more and 7.00 parts by mass or less with respect to 100 parts by mass of the binder resin in the photosensitive layer. Photoconductors having such a configuration tend to have an appropriate electrical resistance. As a result, in the photoreceptor according to the first embodiment, it is considered that the surface potential of the photoreceptor is stably maintained, and the charged polarity of the surface potential is unlikely to be opposite to the charged polarity of the toner. Therefore, it is considered that the photoreceptor according to the first embodiment suppresses a decrease in toner image transferability. Further, in the photoconductor according to the first embodiment, the photoconductor tends to have an appropriate electric resistance uniformly. As a result, it is considered that the occurrence of black spots can be suppressed because the electrical resistance is unlikely to decrease locally on the surface of the photoreceptor. As described above, the photoconductor according to the first embodiment suppresses the occurrence of black spots in the image and suppresses a decrease in transferability of the toner image.

  The photoreceptor is described with reference to FIG. FIG. 1 is a schematic cross-sectional view showing the structure of the photoreceptor 1. The photoreceptor 1 is a positively charged single layer type photoreceptor. The photoreceptor 1 includes a conductive substrate 2 and a photosensitive layer 3. As shown in FIG. 1A, the photosensitive layer 3 is a single-layer type photosensitive layer, and the photosensitive layer 3 is directly provided on the conductive substrate 2. Further, as shown in FIG. 1A, the photosensitive layer 3 may be exposed as the outermost layer. As shown in FIG. 1B, a protective layer 5 may be provided on the photosensitive layer 3. Hereinafter, the conductive substrate and the photosensitive layer will be described.

[1. Conductive substrate]
The conductive substrate includes aluminum or an aluminum alloy. An aluminum alloy is an alloy of aluminum and an element other than aluminum. Examples of elements other than aluminum include manganese (Mn), silicon (Si), magnesium (Mg), copper (Cu), iron (Fe), chromium (Cr), titanium (Ti), and zinc (Zn). Can be mentioned. The aluminum alloy may contain one of these elements as an element other than aluminum, or two or more of these elements. Examples of the aluminum alloy include an Al—Mn alloy (JIS 3000 series), an Al—Mg alloy (JIS 5000 series), and an Al—Mg—Si alloy (JIS 6000 series).

  The conductive substrate has an oxide film. The oxide film is an aluminum oxide film or an aluminum alloy oxide film. The aluminum oxide film or the aluminum alloy oxide film is formed, for example, by oxidizing the surface of a substrate containing aluminum or an aluminum alloy. The method for forming the oxide film will be described later in the method for producing a photoreceptor.

The abundance ratio R of oxygen atoms in the oxide film is preferably 20% or more and 50% or less. The abundance ratio R of oxygen atoms can be calculated using Equation (1).
R = [A _O / (A _O + A _Al )] × 100 (1)
In Equation (1), A 2 _O is oxygen atom concentration, and is obtained by measuring an oxide film using energy dispersive X-ray spectroscopy (EDX). A _Al is the aluminum atom concentration, and can be obtained by measuring an oxide film using energy dispersive X-ray spectroscopy.

  The oxygen atom concentration and the aluminum atom concentration are measured using an energy dispersive X-ray spectrometer (“JSM-6380LV” manufactured by JEOL Ltd.). The measuring method of oxygen atom concentration and aluminum atom concentration will be described later in detail in Examples.

  When the oxygen atom abundance ratio R is 20% or more, the oxide film of the conductive substrate has an appropriate electrical resistance, so that charge injection (electron injection) from the conductive substrate to the photosensitive layer can be suppressed. If the oxygen atom abundance ratio R is 50% or less, the oxide film of the conductive substrate has an appropriate electrical resistance, and therefore it is difficult to inhibit the transport of holes from the photosensitive layer to the conductive substrate.

  The thickness of the oxide film is 1 μm or more and 15 μm or less, and preferably 3 μm or more and 10 μm or less. When the thickness of the oxide film is 1 μm or more and 15 μm or less, the photoreceptor has an appropriate electrical resistance. As a result, charge injection (electron injection) from the conductive substrate to the photosensitive layer can be suppressed. It is difficult to inhibit the transport of holes from the photosensitive layer to the conductive substrate. The thickness of the oxide film is measured using a reflection / transmission thin film measuring instrument (“NANOCALC-VIS” manufactured by Tokyo Instruments Inc.). A method for measuring the thickness of the oxide film will be described later in detail in Examples.

  The shape of the conductive substrate can be appropriately selected according to the structure of the image forming apparatus to be used. For example, a sheet-like conductive substrate or a drum-shaped conductive substrate can be used. Further, the thickness of the conductive substrate can be appropriately selected according to the shape of the conductive substrate.

[2. Photosensitive layer]
As already described, the photosensitive layer includes a charge generating agent, a hole transporting agent, tetracarboxylic dianhydride, and a binder resin. The photosensitive layer may contain an electron transport agent or an additive as necessary. Hereinafter, the tetracarboxylic dianhydride, the charge generator, the electron transport agent, the hole transport agent, the binder resin, and the additive will be described.

(2-1. Tetracarboxylic acid dianhydride)
The tetracarboxylic dianhydride is one or more compounds selected from the group consisting of compounds represented by the general formulas (1), (2), and (3). The compounds represented by the general formulas (1), (2), and (3) may be hereinafter referred to as tetracarboxylic dianhydrides (1), (2), and (3), respectively. The tetracarboxylic dianhydride may be any one of tetracarboxylic dianhydrides (1), (2), and (3), or tetracarboxylic dianhydrides (1), (2 ) And (3) may be any two or more.

In the general formulas (1), (2), and (3), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ (hereinafter sometimes referred to as R ^{1 to} R ¹⁴ ) are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or 1 carbon atom. It represents an alkoxy group having 6 or less or an aryl group having 6 to 14 carbon atoms. The alkoxy group may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom. The alkyl group may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom. The aryl group may have one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen atom.

In general formulas (1) to (3), the halogen atom represented by R ^{1 to} R ¹⁴ is preferably a bromine atom.

In general formulas (1) to (3), the alkyl group having 1 to 6 carbon atoms represented by R ^{1 to} R ¹⁴ is preferably an alkyl group having 1 to 4 carbon atoms, and 1 to 3 carbon atoms. Are more preferable, and a methyl group is still more preferable. The alkyl group having 1 to 6 carbon atoms may have one or more substituents. Such one or more substituents are one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom.

In general formulas (1) to (3), the alkoxy group having 1 to 6 carbon atoms represented by R ^{1 to} R ¹⁴ is preferably an alkoxy group having 1 to 4 carbon atoms, and 1 to 3 carbon atoms. The alkoxy group is more preferable. The alkoxy group having 1 to 6 carbon atoms may have one or more substituents. Such one or more substituents are one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom.

In general formulas (1) to (3), the aryl group having 6 to 14 carbon atoms represented by R ^{1 to} R ¹⁴ is preferably an aryl group having 6 to 10 carbon atoms, more preferably a phenyl group or a naphthyl group. preferable. The aryl group having 6 to 14 carbon atoms may have one or more substituents. The one or more substituents are one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen atom.

In general formula (1), R ¹ , R ² , R ³ , and R ⁴ preferably each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms. In general formula (2), R ⁵ and R ⁶ preferably each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms. In the general formula (3), R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ are each independently a hydrogen atom, a halogen atom, or 1 or more carbon atoms. It is preferable to represent the following alkyl groups.

  Specific examples of tetracarboxylic dianhydride (1) are described as compounds represented by chemical formulas (ADD1-1) to (ADD1-3) (hereinafter referred to as compounds (ADD1-1) to (ADD1-3)). May be included).

  Specific examples of tetracarboxylic dianhydride (2) are described as compounds represented by chemical formulas (ADD2-1) to (ADD2-3) (hereinafter referred to as compounds (ADD2-1) to (ADD2-3)). May be included).

  Specific examples of the tetracarboxylic dianhydride (3) are described as compounds represented by chemical formulas (ADD3-1) to (ADD3-3) (hereinafter referred to as compounds (ADD3-1) to (ADD3-3)). May be included).

  The content of tetracarboxylic dianhydride is 0.07 to 7.00 parts by mass and 0.50 to 5.00 parts by mass with respect to 100 parts by mass of the binder resin. Preferably, it is 0.10 parts by mass or more and 5.00 parts by mass or less.

(2-2. Charge generator)
The charge generator is not particularly limited as long as it is a charge generator for a photoreceptor. Examples of the charge generator include phthalocyanine pigments, perylene pigments, bisazo pigments, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, trisazo pigments, indigo pigments, azurenium pigments, cyanine pigments , Powders of inorganic photoconductive materials (more specifically, selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, amorphous silicon, etc.), pyrylium salts, ansanthrone pigments, triphenylmethane pigments, selenium pigments , Toluidine pigments, pyrazoline pigments, or quinacridone pigments. A charge generating agent may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the phthalocyanine pigment include metal-free phthalocyanine represented by the chemical formula (CGM-1) or metal phthalocyanine. Examples of the crystal of metal-free phthalocyanine include an X-type crystal of metal-free phthalocyanine (hereinafter sometimes referred to as X-type metal-free phthalocyanine). Examples of the metal phthalocyanine include titanyl phthalocyanine represented by the chemical formula (CGM-2) or phthalocyanine coordinated with a metal other than titanium oxide (more specifically, V-type hydroxygallium phthalocyanine, etc.). Examples of the titanyl phthalocyanine crystal include α-type crystal, β-type crystal, and Y-type crystal of titanyl phthalocyanine. The phthalocyanine pigment may be crystalline or non-crystalline. In the case where the conductive substrate has the above oxide film and the photosensitive layer contains tetracarboxylic dianhydride, none of these charge generating agents can be used to further suppress black spots and further improve transferability. Metal phthalocyanine is preferred, and X-type metal-free phthalocyanine is more preferred.

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

  An ansanthrone pigment or a perylene pigment is preferably used as a charge generating agent in a photoreceptor applied to an image forming apparatus using a short wavelength laser. Examples of the wavelength of the short wavelength laser include wavelengths of about 350 nm to 550 nm.

  The content of the charge generating agent is preferably 0.1 parts by mass or more and 50 parts by mass or less, and more preferably 0.5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin.

(2-3. Electron transport agent)
The electron transfer agent is not particularly limited as long as it can be applied to the photoreceptor. Examples of the electron transfer agent include quinone compounds, diimide compounds, hydrazone compounds, malononitrile compounds, thiopyran compounds, trinitrothioxanthone compounds, 3,4,5,7-tetranitro-9-fluorenone compounds, Examples include dinitroanthracene compounds, dinitroacridine compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroacridine, succinic anhydride, maleic anhydride, or dibromomaleic anhydride. Examples of quinone compounds include diphenoquinone compounds, azoquinone compounds, anthraquinone compounds, naphthoquinone compounds, nitroanthraquinone compounds, and dinitroanthraquinone compounds. These electron transfer agents may be used alone or in combination of two or more.

  Of these electron transfer agents, compounds represented by the general formula (4), (5), (6), (7), or (8) are preferable, and (4) is more preferable. The electron transport agent may be used alone or in combination of two or more of the compounds represented by the general formulas (4), (5), (6), (7), and (8). Also good. Hereinafter, the compounds represented by the general formulas (4), (5), (6), (7), and (8) are converted into electron transfer agents (4), (5), (6), (7), And (8).

In the general formula (4), R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , and R ¹⁹ (hereinafter sometimes referred to as R ^{15 to} R ¹⁹ ) each independently represent a hydrogen atom or a carbon atom number of 1 It represents an alkyl group having 6 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms. The alkoxy group may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom. The alkyl group may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom. The aryl group may have one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen atom. R ²⁰ and R ²¹ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

In general formula (4), the alkyl group having 1 to 6 carbon atoms represented by R ^{15 to} R ²¹ is preferably an alkyl group having 1 to 4 carbon atoms, and an alkyl group having 1 to 3 carbon atoms. Are more preferable, and a methyl group or an ethyl group is still more preferable. The alkyl group having 1 to 6 carbon atoms represented by R ^{15 to} R ¹⁹ may have one or more substituents. Such one or more substituents are one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom.

In the general formula (4), the alkoxy group having 1 to 6 carbon atoms represented by R ^{15 to} R ²¹ is preferably an alkoxy group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 3 carbon atoms. Is more preferable. The alkoxy group having 1 to 6 carbon atoms represented by R ^{15 to} R ¹⁹ may have one or more substituents. Such one or more substituents are one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom.

In the general formula (4), the aryl group having 6 to 14 carbon atoms represented by R ^{15 to} R ¹⁹ is preferably an aryl group having 6 to 10 carbon atoms, and more preferably a phenyl group or a naphthyl group. The aryl group having 6 to 14 carbon atoms represented by R ^{15 to} R ¹⁹ may have one or more substituents. Such one or more substituents are one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen atom. is there.

In the general formula (4), R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , R ¹⁹ , R ²⁰ , R ²¹ , R ²² , R ²³ , R ²⁴ , and R ²⁵ are each independently a hydrogen atom or carbon It preferably represents an alkyl group having 1 to 3 atoms, more preferably a hydrogen atom, a methyl group, or an ethyl group.

  Specific examples of the electron transfer agent (4) may be described as compounds represented by chemical formulas (ETM4-1) to (ETM4-2) (hereinafter referred to as compounds (ETM4-1) to (ETM4-2)). ).

In the general formulas (5), (6), (7), and (8), R ²² , R ²³ , R ²⁴ , R ²⁵ , R ²⁶ , R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ , R ³¹ , R ³² , R ³³ , and R ³⁴ (hereinafter sometimes referred to as R ^{22 to} R ³⁴ ) are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or the number of carbon atoms. An alkoxy group having 1 to 6 carbon atoms or an aryl group having 6 to 14 carbon atoms is represented. The alkoxy group may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom. The alkyl group may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom. The aryl group may have one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen atom.

In general formulas (5) to (8), the alkyl group having 1 to 6 carbon atoms represented by R ^{22 to} R ³⁴ is preferably an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, An isopropyl group, a t-butyl group, or a 2-methyl-2-butyl group is more preferable. The alkyl group having 1 to 6 carbon atoms represented by R ^{22 to} R ³⁴ may have one or more substituents. Such one or more substituents are one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom.

In general formulas (5) to (8), the alkoxy group having 1 to 6 carbon atoms represented by R ^{22 to} R ³⁴ is preferably an alkoxy group having 1 to 4 carbon atoms, and 1 to 3 carbon atoms. The following alkoxy groups are more preferred. The alkoxy group having 1 to 6 carbon atoms represented by R ^{22 to} R ³⁴ may have one or more substituents. Such one or more substituents are one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom.

In general formulas (5) to (8), the aryl group having 6 to 14 carbon atoms represented by R ^{22 to} R ³⁴ is preferably an aryl group having 6 to 10 carbon atoms, and a phenyl group or a naphthyl group is More preferred is a phenyl group. The aryl group having 6 to 14 carbon atoms represented by R ^{22 to} R ³⁴ may have one or more substituents. Such one or more substituents are one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen atom. is there. The aryl group having 6 to 10 carbon atoms having one or more substituents is preferably a phenyl group having one or more halogen atoms, and more preferably a dichlorophenyl group.

In general formulas (5) to (8), R ^{22 to} R ³⁴ preferably each independently represent a phenyl group having one or more halogen atoms, or an alkyl group having 1 to 5 carbon atoms, More preferably, it represents a dichlorophenyl group, a methyl group, an ethyl group, an isopropyl group, a t-butyl group, or a 2-methyl-2-butyl group.

  Specific examples of the electron transfer agent (5) may be described as compounds represented by chemical formulas (ETM5-1) to (ETM5-2) (hereinafter referred to as compounds (ETM5-1) to (ETM5-2)). ).

  Specific examples of the electron transfer agent (6) may be described as compounds represented by chemical formulas (ETM6-1) to (ETM6-2) (hereinafter referred to as compounds (ETM6-1) to (ETM6-2)). ).

  Specific examples of the electron transfer agent (7) may be described as compounds represented by chemical formulas (ETM7-1) to (ETM7-2) (hereinafter referred to as compounds (ETM7-1) to (ETM7-2)). ).

  Specific examples of the electron transfer agent (8) may be described as compounds represented by chemical formulas (ETM8-1) to (ETM8-2) (hereinafter referred to as compounds (ETM8-1) to (ETM8-2)). ).

The content of the electron transport agent is preferably 5 parts by mass or more and 100 parts by mass or less, and more preferably 10 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the binder resin.

(2-4. Hole transport agent)
The hole transport agent is not particularly limited as long as it can be applied to the photoreceptor. As the hole transport agent, for example, a nitrogen-containing cyclic compound or a condensed polycyclic compound can be used. Nitrogen-containing cyclic compounds and condensed polycyclic compounds include, for example, triphenylamine derivatives; diamine derivatives (more specifically, N, N, N ′, N′-tetraphenylbenzidine derivatives, N, N, N ', N'-tetraphenylphenylenediamine derivative, N, N, N', N'-tetraphenylnaphthylenediamine derivative, or di (aminophenylethenyl) benzene derivative, or N, N, N ', N'- Tetraphenylphenanthrylenediamine derivatives, etc.); oxadiazole compounds (more specifically, 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole, etc.); styryl compounds (More specifically, 9- (4-diethylaminostyryl) anthracene and the like); Carbazole compounds (more specifically, polyvinylcarbazole and the like); Existence Polysilane compounds; pyrazoline compounds (more specifically, 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline); hydrazone compounds; indole compounds; oxazole compounds; isoxazole compounds; thiazole compounds A thiadiazole compound; an imidazole compound; a pyrazole compound; or a triazole compound. These hole transport agents may be used alone or in combination of two or more.

  Of these hole transporting agents, compounds represented by the general formula (9) or (10) are preferable.

In general formula (9), R ³⁵ represents an alkyl group having 1 to 6 carbon atoms which may have a substituent selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom. Represent. t represents an integer of 0 or more and 2 or less. u represents 1 or 2;

In general formula (10), R ³⁶ , R ³⁷ , R ³⁸ , R ³⁹ , R ⁴⁰ , and R ⁴¹ are each independently selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom. Represents an alkyl group having 1 to 6 carbon atoms which may have a substituent. r, s, v, and w each independently represent an integer of 0 or more and 5 or less. x and y each independently represents an integer of 0 or more and 4 or less.

In general formula (9), the alkyl group having 1 to 6 carbon atoms represented by R ³⁵ is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group, an ethyl group, or an n-butyl group. preferable. The alkyl group having 1 to 6 carbon atoms may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom. The position at which the alkyl group having 1 to 6 carbon atoms represented by R ³⁵ is substituted is the ortho position (o position), meta position (m position), or para position (p position) of the phenyl group with respect to the bond with the nitrogen atom. And the ortho position or para position is preferred.

  Specific examples of the compound represented by the general formula (9) include compounds represented by chemical formulas (HTM9-1) to (HTM9-2) (hereinafter, compounds (HTM9-1) to (HTM9-2) and May be described).

In General Formula (10), the alkyl group having 1 to 6 carbon atoms represented by R ³⁶ , R ³⁷ , R ³⁸ , R ³⁹ , R ⁴⁰ , and R ⁴¹ is an alkyl group having 1 to 3 carbon atoms. Preferably, a methyl group is more preferable. The alkyl group having 1 to 6 carbon atoms may have a substituent selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom. It is preferable that r, s, v, and w each independently represent 0 or 1. x and y preferably represent 0.

  Specific examples of the compound represented by the general formula (10) include compounds represented by chemical formulas (HTM10-1) to (HTM10-2) (hereinafter, compounds (HTM10-1) to (HTM10-2) and May be described).

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

(2-5. Binder resin)
The photosensitive layer can contain a binder resin. Examples of the binder resin include a thermoplastic resin, a thermosetting resin, and a photocurable resin. Examples of the thermoplastic resin include polyester resin, polycarbonate resin, styrene resin, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, styrene-acrylic acid copolymer, acrylic copolymer. Polymer, polyethylene resin, ethylene-vinyl acetate copolymer, chlorinated polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer, vinyl chloride-vinyl acetate copolymer, alkyd resin, polyamide resin, urethane resin, polyarylate resin , Polysulfone resin, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, or polyether resin. Examples of thermosetting resins include silicone resins, epoxy resins, phenolic resins, urea resins, melamine resins, or other crosslinkable thermosetting resins. As an example of a photocurable resin, an epoxy acrylic acid resin or a urethane-acrylic acid copolymer is mentioned. One of these other resins may be used alone, or two or more thereof may be used in combination.

  Of these binder resins, polycarbonate resins are preferred. When the binder resin is a polycarbonate resin, it is easy to obtain a photosensitive layer having an excellent balance of processability, mechanical properties, optical properties, and wear resistance. Among the polycarbonate resins, a bisphenol Z-type polycarbonate resin is preferable and a resin represented by the following chemical formula (Z) is more preferable because the transferability of the toner image by the photoreceptor is easy to improve. In the chemical formula (Z), the suffix of the repeating unit indicates the ratio (molar ratio) of the number of moles of the repeating unit to which the suffix is attached to the sum of the number of moles of all the repeating units in the resin.

  The molecular weight of the binder resin is preferably 40,000 or more in terms of viscosity average molecular weight, and more preferably 40,000 or more and 52,500 or less. When the viscosity average molecular weight of the binder resin is 40,000 or more, it is easy to improve the wear resistance of the photoreceptor. Further, when the molecular weight of the other binder resin is 52,500 or less, the binder resin is easily dissolved in the solvent during the formation of the photosensitive layer, and the viscosity of the coating solution for forming the photosensitive layer does not become too high. As a result, it becomes easy to form a photosensitive layer.

(2-6. Additives)
Examples of the additive include a deterioration inhibitor (more specifically, an antioxidant, a radical scavenger, a quencher, or an ultraviolet absorber), a softener, a surface modifier, a bulking agent, a thickener, A dispersion stabilizer, wax, acceptor, donor, surfactant, plasticizer, sensitizer, or leveling agent may be mentioned. Examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone, or a derivative thereof, an organic sulfur compound, or an organic phosphorus compound.

  The photoconductor according to the first embodiment has been described above. According to the photoconductor according to the first embodiment, it is possible to suppress the occurrence of black spots in an image and to suppress a decrease in transferability of a toner image.

<Second Embodiment: Method for Manufacturing Photoconductor>
The second embodiment relates to a method for manufacturing a photoreceptor. With reference to FIG. 1, the manufacturing method of the photoreceptor 1 is demonstrated. The method for manufacturing the photoreceptor 1 includes an oxide film forming step and a photosensitive layer forming step. Hereinafter, the oxide film forming step and the photosensitive layer forming step will be described.

[1. Oxide film formation process]
In the oxide film forming step, the substrate is immersed in water, taken out from the water and heated to form an oxide film on the surface of the substrate. As a result, the conductive substrate 2 is obtained. The substrate includes aluminum or an aluminum alloy.
Or aluminum alloy.

The volume resistivity of water is 1.0 × 10 ⁶ Ω · cm or more. The temperature of water is 75 ° C. or higher and 95 ° C. or lower, and preferably 80 ° C. or higher and 93 ° C. or lower.

  The time for immersing the substrate in water is 110 seconds to 700 seconds, preferably 120 seconds to 600 seconds, and more preferably 200 seconds to 550 seconds.

  The heating temperature is 100 ° C. or higher and 180 ° C. or lower, preferably 110 ° C. or higher and 160 ° C. or lower, and more preferably 120 ° C. or higher and 155 ° C. or lower. For heating after removal from the water, for example, an oven can be used.

  By setting the volume resistivity of water, the temperature of water, the immersion time in water, and the heating temperature within the above ranges, the conductive substrate 2 having an appropriate electrical resistance can be obtained. In addition, by setting the volume resistivity of water, the temperature of water, the immersion time in water, and the heating temperature within the above ranges, the ratio of oxygen atoms in the oxide film is within a desired range (greater than 20% and less than 50%). It is easy to adjust the film thickness of the oxide film to a desired range (1 μm or more and 15 μm or less).

[2. Photosensitive layer forming step]
In the photosensitive layer forming step, a photosensitive layer forming coating solution (hereinafter sometimes referred to as a coating solution) is applied onto the conductive substrate 2, and at least part of the solvent of the applied coating solution is removed. The photosensitive layer 3 is formed. The photosensitive layer forming step includes, for example, a coating solution preparing step, a coating step, and a drying step. Hereinafter, a coating liquid preparation process, a coating process, and a drying process will be described.

(2-1. Coating liquid preparation step)
In the coating liquid preparation step, a coating liquid is prepared. The coating liquid contains at least a charge generator, a hole transport agent, a tetracarboxylic dianhydride, a binder resin, and a solvent. The coating solution may contain an additive as necessary. The coating solution is prepared by, for example, dissolving or dispersing a charge generator, a hole transport agent, tetracarboxylic dianhydride, a binder resin, and optional components (more specifically, additives) in a solvent. can do.

  The solvent contained in the coating solution is not particularly limited as long as each component contained in the coating solution can be dissolved or dispersed. Examples of the solvent include alcohols (more specifically, methanol, ethanol, isopropanol, butanol, etc.), aliphatic hydrocarbons (more specifically, n-hexane, octane, cyclohexane, etc.), aromatics, and the like. Group hydrocarbons (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, or diethylene glycol dimethyl ether), ketones (more specifically, acetone, methyl ethyl ketone, or cyclohexanone), esters (more specifically, ethyl acetate, or Acetic acid Chill etc.), dimethyl formaldehyde, N, N-dimethylformamide (DMF), or dimethylsulfoxide. These solvents may be used alone or in combination of two or more. Of these solvents, non-halogen solvents are preferred.

  The coating solution is prepared by mixing each component and dissolving or dispersing in a solvent. For mixing, dissolving, or dispersing, for example, a bead mill, a roll mill, a ball mill, an attritor, a paint shaker, or an ultrasonic disperser can be used.

  The coating liquid may contain, for example, a surfactant or a leveling agent in order to improve the dispersibility of each component or the surface smoothness of the formed photosensitive layer.

(2-2. Application process)
In the coating process, a coating solution is applied onto the conductive substrate 2. The method for applying the coating solution is not particularly limited as long as it is a method that can uniformly apply the coating solution on the conductive substrate 2. Examples of the coating method include a dip coating method, a spray coating method, a spin coating method, and a bar coating method.

  Since it is easy to adjust the thickness of the photosensitive layer 3 to a desired value, a dip coating method is preferable as a method of applying the coating solution. When the coating process is performed by a dip coating method, in the coating process, the conductive substrate 2 is immersed in a coating solution. Subsequently, the immersed conductive substrate 2 is pulled up from the coating solution. As a result, the coating liquid is applied to the conductive substrate 2.

(2-3. Drying step)
In the drying step, at least a part of the solvent contained in the coating solution applied on the conductive substrate 2 is removed. The method for removing the solvent contained in the coating solution is not particularly limited as long as it is a method capable of evaporating the solvent in the coating solution. Examples of the removal method include heating, reduced pressure, or combined use of heating and reduced pressure. More specifically, a method of performing heat treatment (hot air drying) using a high-temperature dryer or a vacuum dryer can be mentioned. The heat treatment conditions are preferably, for example, a temperature of 40 ° C. or higher and 150 ° C. or lower and a time of 3 minutes or longer and 120 minutes or shorter.

  In addition, the manufacturing method of the photoreceptor 1 may further include one or both of the steps of forming the protective layer 5 as necessary. In the step of forming the protective layer 5, a known method is appropriately selected.

  The method for manufacturing the photoreceptor 1 according to the second embodiment has been described above with reference to FIG. According to the method for manufacturing the photoconductor 1 according to the second embodiment, it is possible to provide a method for manufacturing a photoconductor that suppresses the occurrence of black spots in an image and suppresses a decrease in transferability of a toner image.

<Third embodiment: Image forming apparatus>
The third embodiment relates to an image forming apparatus. The image forming apparatus according to the third embodiment includes an image carrier, a charging unit, an exposure unit, a developing unit, and a transfer unit. The charging unit charges the surface of the image carrier. The exposure unit exposes the surface of the charged image carrier to form an electrostatic latent image on the surface of the image carrier. The developing unit develops the electrostatic latent image as a toner image. The transfer unit transfers the toner image from the image carrier to the transfer member. The charging polarity of the charging unit is positive. The image carrier is the photoreceptor according to the first embodiment.

  The image forming apparatus according to the third embodiment includes the photoconductor according to the first embodiment as an image carrier. The photoconductor according to the first embodiment can suppress a decrease in transferability of the toner image and suppress the occurrence of black spots. Therefore, the image forming apparatus according to the third embodiment can suppress the occurrence of image defects. Image defects include, for example, image defects caused by the occurrence of black spots in the image and a decrease in toner image transferability. As an example of the image defect, an image defect caused by a decrease in toner image transferability will be described.

  When the transferability of the toner image is reduced as described above, the toner that could not be transferred to the transfer member remains on the image carrier. Residual toner may be transferred to an image formed in the next round of the image carrier. An image defect in which an image reflecting the previous round image of the image carrier is formed is an image defect caused by a decrease in toner image transferability.

  With reference to FIG. 2, an image in which an image defect has occurred will be further described. FIG. 2 is a schematic diagram illustrating an image in which an image defect has occurred. This image defect is an image defect generated due to a decrease in transferability of the toner image. The image 100 has a region 102, a region 104, and a region 106. The area 102, the area 104, and the area 106 are areas corresponding to one turn in the direction a (conveying direction a) of the image carrier. The direction a is a direction in which the recording medium is conveyed. Region 102 includes an image 108. The image 108 is a rectangular solid image (image density 100%). An image other than the image 108 in the region 102 is a blank paper image (image density 0%). The area 104 and the area 106 each include an entire blank image (image density 0%) on the design image. In the direction a, first, the image 108 and the blank image of the region 102 are formed, then the blank image of the region 104 is formed, and finally, the blank image of the region 106 is formed. The blank paper image in the area 104 is an image corresponding to one round of the next rotation of the image carrier, and the first round of the image carrier forming the image 108 is used as a reference for one round of the image carrier of the second round. The corresponding image. The blank paper image in the area 106 is an image corresponding to one round of the next rotation of the image carrier, and one round of the image carrier 1 on the third round with reference to the first round of the image carrier forming the image 108. It is an image equivalent to.

  The blank paper image in the area 110 of the area 104 is an image corresponding to the image 108 in the second turn of the image carrier. The blank paper image in the area 112 of the area 106 is an image corresponding to the image 108 in the third round of the image carrier. In this case, an image reflecting the image 108 is formed in the area 110 and / or the area 112 as an image defect. As described above, the image defect due to the decrease in the transferability of the toner image occurs in a cycle with the circumference of the image carrier 1 as a unit. Images reflecting the image 108 are easily formed on both ends of the recording medium. This is considered to be because the pressing force to both ends of the recording medium is relatively strong. Here, the both end portions of the recording medium are, for example, both end portions in the vertical direction b (region 110L and region 110R) in the region 110 of the recording medium, and both end portions (region 112L and region 112R in the vertical direction b in the region 112. ).

  The image forming apparatus 10 according to the third embodiment will be described below with reference to FIG. FIG. 3 shows an example of the configuration of the image forming apparatus 10 according to the third embodiment.

  The image forming apparatus 10 is not particularly limited as long as it is an electrophotographic image forming apparatus. For example, the image forming apparatus 10 may be a monochrome image forming apparatus or a color image forming apparatus. When the image forming apparatus 10 is a color image forming apparatus, the image forming apparatus 10 employs, for example, a tandem method. Hereinafter, the tandem image forming apparatus 10 will be described as an example.

  The image forming apparatus 10 includes image forming units 40a, 40b, 40c, and 40d, a transfer belt 50, and a fixing unit 52. Hereinafter, when it is not necessary to distinguish, each of the image forming units 40a, 40b, 40c, and 40d is referred to as an image forming unit 40.

  The image forming unit 40 includes the image carrier 1, a charging unit 42, an exposure unit 44, a developing unit 46, and a transfer unit 48. The image carrier 1 is provided at the center position of the image forming unit 40. The image carrier 1 is provided to be rotatable in the arrow direction (counterclockwise). Around the image carrier 1, a charging unit 42, an exposure unit 44, a developing unit 46, and a transfer unit 48 are provided in this order from the upstream side in the rotation direction of the image carrier 1 with the charging unit 42 as a reference. The image forming unit 40 may further include one or both of a cleaning unit (not shown) and a charge removal unit (not shown).

  The charging unit 42 charges the surface of the image carrier 1. The charging polarity of the charging unit is positive. The charging unit 42 is a non-contact type or contact type charging unit. Examples of the non-contact charging unit 42 include a corotron charger and a scorotron charger. Examples of the contact-type charging unit 42 include a charging roller or a charging brush.

  The image forming apparatus 10 can include a charging roller as the charging unit 42. When charging the surface of the image carrier 1, the charging roller comes into contact with the surface of the image carrier 1. When a minute component adheres to the surface of the image carrier 1, the minute component is pressed against the surface of the image carrier 1 by the charging roller that has come into contact. Thereby, a minute component is easily fixed on the surface of the image carrier 1. For this reason, normally, in an image forming apparatus provided with a charging roller, black spots tend to occur on an image. However, the image forming apparatus 10 includes the photoreceptor 1 according to the first embodiment as the image carrier 1. The photoreceptor 1 according to the first embodiment can suppress the occurrence of black spots on an image. Therefore, the image forming apparatus according to the third embodiment suppresses the occurrence of black spots and suppresses the occurrence of image defects due to the occurrence of black spots on the image even when the charging unit 42 includes a charging roller. Can do.

  The exposure unit 44 exposes the surface of the charged image carrier 1. As a result, an electrostatic latent image is formed on the surface of the image carrier 1. The electrostatic latent image is formed based on the image data input to the image forming apparatus 10.

  The developing unit 46 supplies toner to the surface of the image carrier 1 and develops the electrostatic latent image as a toner image.

  The developing unit 46 can clean the surface of the image carrier 1. That is, the image forming apparatus 10 can employ a so-called blade cleaner-less method. The developing unit 46 can remove components remaining on the surface of the image carrier 1 (hereinafter sometimes referred to as residual components). An example of the residual component is a toner component, and more specifically, a toner or a free external additive. Another example of the residual component is a non-toner component (micro component), more specifically, paper dust. In the image forming apparatus 10 that employs the blade cleaner-less method, since there is no cleaning blade as a cleaning unit, residual components on the surface of the image carrier 1 are not sufficiently scraped off. Therefore, in the image forming apparatus 10 that employs the blade cleaner-less method, usually, residual components tend to remain on the surface of the image carrier 1, and black spots are easily generated on the image due to the residual components. However, since the image carrier 1 can easily suppress the occurrence of black spots on the image, the image forming apparatus 10 including such an image carrier 1 employs a blade cleaner-less method, and minute components are formed on the surface of the image carrier 1. Even if it remains, it is possible to suppress the occurrence of image defects due to black spots on the image.

In order for the developing unit 46 to efficiently clean the surface of the image carrier 1, it is preferable to satisfy the following conditions (a) and (b).
Condition (a): A contact developing method is adopted, and a peripheral speed (rotational speed) difference is provided between the image carrier 1 and the developing unit 46.
Condition (b): The surface potential of the image carrier 1 and the potential of the developing bias satisfy the following formulas (b-1) and (b-2).
0 (V) <potential of developing bias (V) <surface potential of unexposed area of image carrier 1 (V) (b-1)
Development bias potential (V)> Surface potential (V) of the exposure area of the image carrier 1> 0 (V) (b-2)

  When the contact development method shown in the condition (a) is adopted and a peripheral speed difference is provided between the image carrier 1 and the development unit 46, the surface of the image carrier 1 comes into contact with the development unit 46, and the image Adhering components on the surface of the carrier 1 are removed by friction with the developing unit 46. The peripheral speed of the developing unit 46 is preferably faster than the peripheral speed of the image carrier 1.

  In condition (b), it is assumed that the charging polarity of the toner, the surface potential of the unexposed area of the image carrier 1, the surface potential of the exposed area of the image carrier 1, and the potential of the developing bias are all positive. doing. That is, it is assumed that the development method is a reversal development method. The timing at which the surface potential of the unexposed area of the image carrier 1 and the surface potential of the exposed area are measured is after the transfer unit 48 has transferred the toner image from the image carrier 1 to the recording medium P and is charged. This is before the portion 42 charges the surface of the next image carrier 1.

  When the mathematical expression (b-1) of the condition (b) is satisfied, it acts between the toner remaining on the image carrier 1 (hereinafter sometimes referred to as residual toner) and the unexposed area of the image carrier 1. The electrostatic repulsive force is larger than the electrostatic repulsive force acting between the residual toner and the developing unit 46. Therefore, residual toner in the unexposed area of the image carrier 1 moves from the surface of the image carrier 1 to the developing unit 46 and is collected.

  When the mathematical expression (b-2) of the condition (b) is satisfied, an electrostatic repulsive force that acts between the residual toner and the exposed area of the image carrier 1 acts between the residual toner and the developing unit 46. Smaller than electric repulsion. Therefore, the residual toner in the exposed area of the image carrier 1 is held on the surface of the image carrier 1. The toner held in the exposure area of the image carrier 1 is used as it is for image formation.

  The transfer belt 50 conveys the recording medium P between the image carrier 1 and the transfer unit 48. The transfer belt 50 is an endless belt. The transfer belt 50 is provided to be rotatable in the arrow direction (clockwise).

  The transfer unit 48 transfers the toner image developed by the developing unit 46 from the surface of the image carrier 1 to the transfer member (recording medium P). When the toner image is transferred from the image carrier 1 to the recording medium P, the image carrier 1 is in contact with the recording medium P. That is, the image forming apparatus 10 employs a so-called direct transfer method. Usually, in an image forming apparatus that employs a direct transfer method, a toner image is transferred by contact between a photoconductor and a recording medium, so that minute components on the recording medium P tend to adhere to the surface of the photoconductor. For this reason, an image forming apparatus that employs the direct transfer method usually tends to cause image defects. However, the image forming apparatus according to the third embodiment includes the photoconductor according to the first embodiment. The photoconductor according to the first embodiment suppresses the occurrence of black spots on the image and suppresses the transferability of the toner image. Therefore, the image forming apparatus according to the third embodiment can suppress image defects. An example of the transfer unit 48 is a transfer roller. In the direct transfer method, the transfer body corresponds to the recording medium P. The image forming apparatus can also employ a so-called intermediate transfer method. In an image forming apparatus that employs an intermediate transfer method, the transfer member corresponds to an intermediate transfer member (for example, an intermediate transfer belt).

  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. When the image forming apparatus 10 is a monochrome image forming apparatus, the image forming apparatus 10 includes an image forming unit 40a, and the image forming units 40b to 40d are omitted.

  The fixing unit 52 heats and / or pressurizes the unfixed toner image transferred to the recording medium P by the transfer unit 48. The fixing unit 52 is, for example, a heating roller and / or a pressure roller. The toner image is fixed on the recording medium P by heating and / or pressurizing the toner image. As a result, an image is formed on the recording medium P.

  The image forming apparatus according to the third embodiment has been described above. The image forming apparatus according to the third embodiment includes the photoconductor according to the first embodiment as an image carrier, thereby causing an image defect (particularly, an image defect due to occurrence of black spots and a decrease in toner image transferability). Can be suppressed.

<Fourth embodiment: Process cartridge>
The fourth embodiment relates to a process cartridge. A process cartridge according to the fourth embodiment includes the photoconductor according to the first embodiment. Next, a process cartridge according to the fourth embodiment will be described with reference to FIG. The process cartridge includes a unitized image carrier 1. The process cartridge may employ a configuration in which at least one selected from the group consisting of the charging unit 42, the exposure unit 44, the developing unit 46, and the transfer unit 48 is unitized in addition to the image carrier 1. The process cartridge corresponds to each of the image forming units 40a to 40d, for example. The process cartridge may further include one or both of a cleaning unit (not shown) and a charge removal unit (not shown). The process cartridge is designed to be detachable from the image forming apparatus 10. Therefore, the process cartridge is easy to handle, and when the sensitivity characteristics and the like of the image carrier 1 are deteriorated, the process cartridge can be easily and quickly replaced including the image carrier 1.

  The process cartridge according to the fourth embodiment has been described above. The process cartridge according to the fourth embodiment includes the photoconductor according to the first embodiment as an image carrier, thereby causing an image defect (particularly, an image defect due to the occurrence of black spots on the image and a decrease in toner image transferability). ) Can be suppressed.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the scope of the examples.

[1. Photoconductor Material]
As materials for forming the photosensitive layer of the photoreceptor, the following tetracarboxylic dianhydrides, electron transport agents, hole transport agents, charge generators, and binder resins were prepared.

  The tetracarboxylic dianhydrides (ADD1-1) to (ADD1-4), (ADD2-1) to (ADD2-4), and (ADD3-1) to (ADD3-4) described in the first embodiment are used. Got ready.

  As the electron transport agent, the compounds (ETM4-1) to (ETM4-3), (ETM5-1) to (ETM5-3), (ETM6-1) to (ETM6-3) described in the first embodiment, ( ETM7-1) to (ETM7-3) and (ETM8-1) to (ETM8-3) were prepared.

  As the hole transport agent, the compounds (HTM9-1) to (HTM9-2) and (HTM10-1) to (HTM10-2) described in the first embodiment were prepared.

  A compound (CGM-1X) was prepared as a charge generator. The compound (CGM-1X) was a metal-free phthalocyanine represented by the chemical formula (CGM-1) described in the first embodiment. Furthermore, the crystal structure of the compound (CGM-1X) was X-type.

  A polycarbonate resin (Za) (viscosity average molecular weight 5000) was prepared as a binder resin. The polycarbonate resin (Za) was a polycarbonate resin represented by the chemical formula (Z) described in the first embodiment.

[2. Production of photoconductor]
Photoconductors (E-1) to (E-34) and photoconductors (F-1) to (F-14) were produced using the material for forming the photosensitive layer of the prepared photoconductor.

(2-1. Oxide film forming step)
(2-1-1. Production of Conductive Substrate (A-1))
First, the oxide film formation process was performed. An aluminum substrate having a diameter of 160 mm, a length of 365 mm, and a thickness of 2 mm was prepared. This substrate was immersed in water at 90 ° C. for 200 seconds. And the base | substrate was taken out from water. The substrate was heated at 130 ° C. in an air atmosphere using an oven. The volume resistivity of water was 2.5 × 10 ⁶ Ω · cm. As a result, a conductive substrate (A-1) was obtained.

(2-1-2. Production of Conductive Substrates (A-2) to (A-15) and (B-1) to (B-7))
The conductive substrate (A-2) was produced in the same manner as the production of the conductive substrate (A-1) except that the conditions (temperature of water, immersion time, and heating temperature) of the oxide film forming step shown in Table 1 were changed. -(A-15) and (B-1)-(B-7) were produced.

(2-2. Photosensitive layer forming step)
(2-2-1. Production of Photosensitive Member (E-1))
Next, a photosensitive layer forming step was performed. First, a coating solution was prepared. 1.00 parts by mass of tetracarboxylic dianhydride, 2 parts by mass of a compound (CGM-1X) as a charge generating agent, 60 parts by mass of a compound (HTM9-1) as a hole transporting agent, and as an electron transporting agent 35 parts by mass of the compound (ETM4-1), 100 parts by mass of a polycarbonate resin (Za) as a binder resin, and 800 parts by mass of tetrahydrofuran as a solvent were put in a container. The contents of the container were mixed and dispersed for 50 hours using a ball mill to obtain a coating solution.

  Next, the coating liquid was applied onto the conductive substrate (A-1) obtained in the oxide film formation step by using a dip coating method, thereby forming a coating film on the conductive substrate (A-1). Specifically, the conductive substrate (A-1) was immersed in the coating solution. Next, the immersed conductive substrate (A-1) was pulled up from the coating solution. Thereby, the coating liquid was applied to the conductive substrate (A-1).

  Next, the conductive substrate (A-1) coated with the coating solution was dried with hot air at 100 ° C. for 40 minutes. As a result, the solvent (tetrahydrofuran) contained in the coating solution applied to the conductive substrate (A-1) was removed. As a result, a photosensitive layer (C-1) was formed on the conductive substrate (A-1). As a result, a photoreceptor (E-1) was obtained.

(2-2-2. Production of photoconductors (E-2) to (E-34) and photoconductors (F-1) to (F-14))
Except for the following changes, the photoconductors (E-2) to (E-34) and the photoconductors (F-1) to (F-14) are produced in the same manner as in the production of the photoconductor (E-1). ) Was manufactured. In the production of the photoreceptor (E-1), the conductive substrate (A-1) is changed to any one of the conductive substrates (A-2) to (A-15) and (B-1) to (B-7). did. And the compound (ADD1-1) as a tetracarboxylic dianhydride used for adjustment of the coating liquid in a photosensitive layer formation process, the compound (ETM4-1) as an electron transport agent, and the compound (HTM9) as a hole transport agent -1) was changed to the types of tetracarboxylic dianhydrides, electron transport agents, and hole transport agents shown in Table 2 or Table 3, respectively. Further, the content of tetracarboxylic dianhydride with respect to 100 parts by mass of the binder resin was changed to the content shown in Table 3. Tables 4 and 5 show the relationship between the conductive substrate and the photosensitive layer.

[3. Measuring method]
(3-1. Measurement of oxide film)
The thickness of the oxide film was measured using a reflection / transmission thin film measuring instrument (“NANOCALC-VIS” manufactured by Tokyo Instruments Inc.).

[4. Evaluation method]
(4-1. Measurement of surface potential of photoreceptor)
The surface potential of the exposed area of the photoreceptor was measured using a surface potential meter (“MODEL244” manufactured by Monroe Electronics). This surface potential was the surface potential of the exposed area of the photoconductor after the toner image was transferred from the surface of the photoconductor to the recording medium and before the charging portion charged the surface of the photoconductor on the next round. . Specifically, a surface potential probe (“MODEL1017AS” manufactured by Monroe Electronics) was installed at the position of the exposure area after transfer, and the surface potential was measured. This measurement was performed under the conditions of a temperature of 23 ° C., a relative humidity of 50% RH, a drum linear velocity of 165 mm / sec, a charging voltage of +600 V, a flow-in current of 300 μA, an exposure wavelength of 780 nm, and an exposure dose of 1.2 μJ / cm ² .

The transferability using the surface potential was evaluated from the measured surface potential based on the following criteria. Table 6 and Table 7 show the measured surface potential and evaluation results.
(Evaluation criteria for transferability using surface potential)
○ (good): The measured surface potential was 0 V or more.
X (Poor): The measured surface potential was less than 0V.

(4-2. Evaluation of transferability of toner image by photoreceptor)
The photoconductor was mounted on an evaluation machine. As an evaluation machine, a printer (“FS-1300D” manufactured by Kyocera Document Solutions Co., Ltd., a dry electrophotographic printer using a semiconductor laser) was used. The evaluator was provided with a charging roller as a charging unit. A DC voltage was applied to the charging roller. The evaluation machine was provided with a direct transfer type transfer section (transfer roller). The evaluator was equipped with a contact developing type developing unit. For the transferability evaluation, “Kyocera Document Solutions Brand Paper VM-A4 (A4 size)” sold by Kyocera Document Solutions Inc. was used as the paper. For transferability evaluation, “TK-131” manufactured by Kyocera Document Solutions Co., Ltd. was used as the toner. The transferability evaluation was performed in a high temperature and high humidity (temperature: 32.5 ° C., humidity: 80% RH) environment.

  An evaluation image was formed on a sheet using an evaluation machine equipped with a photoreceptor and toner. Details of the evaluation image will be described later with reference to FIG. The image forming condition was set to a linear velocity of 165 mm / sec. The current applied by the transfer roller to the photoconductor was set to -25 μA.

  Next, the obtained image was visually confirmed, and it was confirmed whether there was an image defect due to a decrease in transferability of the toner image. From the obtained visual observation results, the transferability of the toner image by the photoconductor was evaluated according to the following criteria. ◎ (Very good) and ○ (Good) were accepted. The evaluation results are shown in Tables 6 and 7.

  The evaluation image will be described with reference to FIG. FIG. 4 is a schematic diagram showing an evaluation image. The evaluation image 200 includes a region 202, a region 204, and a region 206. A region 202 is a region corresponding to one rotation of the image carrier. The area 202 is composed of a white image (image density 0%) and a solid image (image density 100%) as the image 208. This solid image had a rectangular shape.

  The region 204 and the region 206 are regions corresponding to one rotation of the image carrier, and each includes a blank paper image (image density 0%). First, the image 208 and the blank image of the region 202 were formed along the conveyance direction a, and then the blank image of the region 204 and the region 206 was formed. A blank image in the region 204 is an image formed on the second turn with the circumference of the photoconductor on which the image 208 is formed as a reference (first turn).

  An area 210 is an area corresponding to the image 208 in the area 204. The blank paper image in the area 206 is an image formed on the third turn with the circumference (first turn) of the photoreceptor on which the image 208 is formed as a reference (first turn). An area 212 is an area corresponding to the image 208 in the area 206.

(Evaluation criteria for transferability using evaluation images)
A (very good): The image corresponding to the image 208 was not confirmed in the area 210 and the area 212.
○ (Good): Images corresponding to the image 208 were slightly confirmed at both ends of the area 210 in the vertical direction b. An image corresponding to the image 208 was not confirmed in the area 212.
Δ (bad): Images corresponding to the image 208 were clearly confirmed at both ends of the area 210 in the vertical direction b. An image corresponding to the image 208 was not confirmed in the area 212.
X (very bad): Images corresponding to the image 208 were clearly confirmed at both ends of the area 210 and the area 212 in the vertical direction b.

(4-3. Image evaluation on black spots)
As an evaluation machine, a printer (“FS-1300D” manufactured by Kyocera Document Solutions Co., Ltd., a dry electrophotographic printer using a semiconductor laser) was used. The evaluator was provided with a charging roller as a charging unit. The charging polarity of the charging part was positive. The evaluation machine was provided with a direct transfer type transfer section (transfer roller). The developing section of the evaluation machine had a photoreceptor cleaning function. For the evaluation, “Kyocera Document Solutions Brand Paper VM-A4 (A4 size)” manufactured by Kyocera Document Solutions Inc. was used as the paper. For each evaluation, “toner for non-magnetic one component” manufactured by Kyocera Document Solutions Co., Ltd. was used as the toner. The measurement environment for each evaluation was a high-temperature and high-humidity environment (temperature: 32.5 ° C., humidity: 80% RH). The photoconductor was mounted on an evaluation machine. The image forming condition was set to a linear velocity of 168 mm / sec. In order to stabilize the operation of the photoconductor of the evaluation machine, 1000 alphabet images were printed. Subsequently, one image D was printed and used as a black spot evaluation sample. Image D was a full blank image. The obtained sample for evaluation was visually observed to observe the presence or absence of black spots. Based on the observation results, image evaluation on black spots was performed according to the following evaluation criteria.
(Evaluation criteria for image evaluation for sunspots)
○ (Good): The number of black spots was 1 or less.
X (bad): The number of black spots exceeded one.

  As shown in Tables 1 to 5, in the photoreceptors (E-1) to (E-48), the thickness of the oxide film was 1.5 μm or more and 14.5 μm or less. The photosensitive layer contained tetracarboxylic dianhydride. The tetracarboxylic dianhydride was a compound represented by the general formula (1), (2), or (3). The content of tetracarboxylic dianhydride was 0.50 parts by mass or more and 5.00 parts by mass or less with respect to 100 parts by mass of the binder resin.

  As shown in Tables 6 to 7, in the photoreceptors (E-1) to (E-48), the evaluation results for the occurrence of black spots are all “good”, and the evaluation results for the transferability of the toner image are all “good”. (Good).

  As shown in Tables 1, 3, and 5, the photoreceptor (F-1) had no oxide film. In the photoreceptors (F-2) to (F-7), the thickness of the oxide film was 0.9 μm or less or 16.1 μm or more. In photoreceptors (F-8) to (F-11), the content of tetracarboxylic dianhydride was 0.01 parts by mass or less or 10.0 parts by mass or more with respect to 100 parts by mass of the binder resin. In Table 7, for the photoreceptor (F-10), the transferability evaluation result “−” indicates that crystallization occurred in the photosensitive layer and measurement was not possible.

  As shown in Table 7, in the photoreceptors (F-1) to (F-11), at least one of the evaluation result of black spot generation and the evaluation result of toner image transferability was x.

  As described above, the photoconductors (E-1) to (E-48) suppress the deterioration of the transferability of the toner image by the photoconductor as compared with the photoconductors (F-1) to (F-11). It is clear to suppress the occurrence.

  The photoreceptor according to the present invention can be suitably used in an electrophotographic image forming apparatus.

1 Photoconductor (Electrophotographic photoconductor)
2 Conductive substrate 3 Photosensitive layer 10 Image forming apparatus 42 Charging unit 44 Exposure unit 46 Development unit 48 Transfer unit

Claims (14)

An electrophotographic photoreceptor comprising a conductive substrate and a photosensitive layer provided directly on the conductive substrate,
The conductive substrate has an oxide film,
The thickness of the oxide film is 1 μm or more and 15 μm or less,
The photosensitive layer is a single-layer type photosensitive layer,
The photosensitive layer includes a charge generator, a hole transport agent, a tetracarboxylic dianhydride, and a binder resin.
The tetracarboxylic dianhydride is one or more compounds selected from the group consisting of compounds represented by the general formulas (1), (2), and (3),
The content of the tetracarboxylic dianhydride is 0.02 parts by mass or more and 7.00 parts by mass or less with respect to 100 parts by mass of the binder resin.

In the general formulas (1), (2), and (3),
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are each independently a hydrogen atom, A halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms,
The alkoxy group may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom,
The alkyl group may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom,
The aryl group may have one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen atom. The oxygen atom abundance ratio R in the oxide film is 20% or more and 50% or less,
The electrophotographic photosensitive member according to claim 1, wherein the abundance ratio R is calculated from Equation (1).
R = [A _O / (A _O + A _Al )] × 100 (1)
In the formula (1),
A _O is the oxygen atom concentration obtained by measuring the oxide film using energy dispersive X-ray spectroscopy,
A _Al is the aluminum atom concentration obtained by measuring the oxide film using energy dispersive X-ray spectroscopy. In the general formula (1), R ¹ , R ² , R ³ , and R ⁴ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms,
In the general formula (2), R ⁵ and R ⁶ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms,
In the general formula (3), R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ are each independently a hydrogen atom, a halogen atom, or one or more carbon atoms. The electrophotographic photosensitive member according to claim 1, which represents 3 or less alkyl groups. The photosensitive layer further includes a compound represented by the general formula (4), (5), (6), (7), or (8) as an electron transport agent. The electrophotographic photoreceptor described in 1.

In the general formula (4),
R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , and R ¹⁹ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or the number of carbon atoms Represents an aryl group of 6 or more and 14 or less,
The alkoxy group may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom,
The alkyl group may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom,
The aryl group may have one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen atom,
R ²⁰ and R ²¹ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

In the general formulas (5), (6), (7), and (8),
R ²² , R ²³ , R ²⁴ , R ²⁵ , R ²⁶ , R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ , R ³¹ , R ³² , R ³³ , and R ³⁴ are each independently a hydrogen atom or a halogen atom Represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms,
The alkoxy group may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom,
The alkyl group may have one or more substituents selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom,
The aryl group may have one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen atom. In the general formula (4),
R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , R ¹⁹ , R ²⁰ , and R ²¹ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,
In the general formulas (5), (6), (7), and (8),
R ²² , R ²³ , R ²⁴ , R ²⁵ , R ²⁶ , R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ , R ³¹ , R ³² , R ³³ , and R ³⁴ are each independently one or more halogens The electrophotographic photoreceptor according to claim 4, which represents a phenyl group having an atom or an alkyl group having 1 to 5 carbon atoms.   The electrophotographic photosensitive member according to any one of claims 1 to 5, wherein the charge generating agent includes X-type metal-free phthalocyanine. The electrophotographic photosensitive member according to claim 1, wherein the hole transport agent includes a compound represented by the general formula (9) or (10).

In the general formula (9),
R ³⁵ represents an alkyl group having 1 to 6 carbon atoms which may have a substituent selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom;
t represents an integer of 0 or more and 2 or less,
u represents 1 or 2,
In the general formula (10),
R ³⁶ , R ³⁷ , R ³⁸ , R ³⁹ , R ⁴⁰ , and R ⁴¹ each independently have a substituent selected from the group consisting of an alkoxy group having 1 to 6 carbon atoms and a halogen atom. Represents an alkyl group having 1 to 6 carbon atoms,
r, s, v, and w each independently represent an integer of 0 to 5,
x and y each independently represents an integer of 0 or more and 4 or less. It is a manufacturing method of the electrophotographic photosensitive member as described in any one of Claims 1-7,
An oxide film forming step of immersing the substrate in water , taking it out of the water and heating to form the oxide film on the surface of the substrate;
And a photosensitive layer forming step of forming a photosensitive layer by applying a photosensitive layer forming coating solution on the conductive substrate and removing at least a part of the solvent contained in the applied photosensitive layer forming coating solution. ,
The substrate includes aluminum or an aluminum alloy,
The photosensitive layer forming coating solution includes the charge generating agent, the hole transport agent, the tetracarboxylic dianhydride, the binder resin, and the solvent.
The volume resistivity of the water is 1.0 × 10 ⁶ Ω · cm or more,
The temperature of the water is 75 ° C. or higher and 95 ° C. or lower,
The time for immersing the substrate in the water is 110 seconds or more and 700 seconds or less,
The method for producing an electrophotographic photosensitive member, wherein the heating is performed at a heating temperature of 100 ° C. or higher and 180 ° C. or lower.   A process cartridge comprising the electrophotographic photosensitive member according to claim 1. An image carrier;
A charging unit that charges the surface of the image carrier;
An exposure unit that exposes the surface of the charged image carrier to form an electrostatic latent image on the surface of the image carrier;
A developing unit for developing the electrostatic latent image as a toner image;
An image forming apparatus comprising: a transfer unit that transfers the toner image from the image carrier to a transfer member;
The charging polarity of the charging part is positive.
The image forming apparatus according to claim 1, wherein the image carrier is the electrophotographic photosensitive member according to claim 1.   The image forming apparatus according to claim 10, wherein the developing unit develops the electrostatic latent image as the toner image while being in contact with the image carrier.   The image forming apparatus according to claim 10, wherein the developing unit cleans the surface of the image carrier.   The image forming apparatus according to claim 10, wherein the transfer body is a recording medium. The image forming apparatus according to claim 10, wherein the charging unit is a charging roller.

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