JP2018021961A - Single-layer electrophotographic photoreceptor, image forming apparatus, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single-layer electrophotographic photoreceptor that is excellent in filming resistance and reduces the occurrence of transfer memory.SOLUTION: A single-layer electrophotographic photoreceptor comprises a conductive substrate and a photosensitive layer. The photosensitive layer is a single-layer photosensitive layer. The photosensitive layer includes a charge generating agent, a hole transport agent, an electron transport agent, a binder resin, an n-type pigment, and filler particles. The charge generating agent contains a phthalocyanine pigment. The content of the n-type pigment is 0.03 parts by mass or more and 3 parts by mass or less relative to 1 part by mass of phthalocyanine pigment. The filler particles are silica particles or resin particles.SELECTED DRAWING: Figure 1

Description

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

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

  The photosensitive layer provided in the single-layer electrophotographic photoreceptor described in Patent Document 1 includes titanyl phthalocyanine and silicon phthalocyanine.

JP 2002-196520 A

  However, the single-layer electrophotographic photosensitive member described in Patent Document 1 has insufficient filming resistance, and the generation of a transfer memory cannot be sufficiently suppressed.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a single-layer electrophotographic photosensitive member that has excellent filming resistance and suppresses the generation of a transfer memory. Another object of the present invention is to provide an image forming apparatus and a process cartridge that suppress the occurrence of image defects.

  The single layer type electrophotographic photosensitive member of the present invention includes a conductive substrate and a photosensitive layer. The photosensitive layer is a single-layer type photosensitive layer. The photosensitive layer includes a charge generating agent, a hole transporting agent, an electron transporting agent, a binder resin, an n-type pigment, and filler particles. The charge generating agent includes a phthalocyanine pigment. The content of the n-type pigment is 0.03 parts by mass or more and 3 parts by mass or less with respect to 1 part by mass of the phthalocyanine pigment. The filler particles are silica particles or resin particles.

  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 image carrier is the above-described electrophotographic photosensitive member. The charging unit charges the surface of the image carrier. The charging polarity of the charging unit is positive. 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 using a developer. The transfer unit transfers the toner image from the image carrier to the recording medium while the surface of the image carrier and the recording medium are in contact with each other.

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

  According to the single layer type electrophotographic photosensitive member of the present invention, the filming resistance is excellent and the generation of a transfer memory can be suppressed. Further, according to the image forming apparatus and the process cartridge of the present invention, it is possible to suppress the occurrence of image defects.

(A), (b) and (c) are schematic sectional views showing an example of the electrophotographic photosensitive member according to the first embodiment of the present invention. It is a figure which shows an example of the image forming apparatus which concerns on 2nd embodiment of this invention. It is a figure which shows the image in which the image ghost generate | occur | produced. It is a figure which shows the image for evaluation.

  Hereinafter, embodiments of the present invention will be described in detail. 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, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 3 carbon atoms, carbon An alkenyl group having 2 to 6 atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and 7 to 10 carbon atoms An aralkyloxy group having 7 to 20 carbon atoms, an aralkyloxy group having 7 to 10 carbon atoms, a heterocyclic group having 3 to 14 carbon atoms, and a cycloalkylidene having 5 to 7 carbon atoms. A group and an amino group have the following meanings unless otherwise specified.

  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, pentyl group, isopentyl group, A neopentyl group or a hexyl group is mentioned. The alkyl group having 1 to 6 carbon atoms may have one or more substituents. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, and a cyano group.

  The alkyl group having 1 to 5 carbon atoms is linear or branched and unsubstituted. Examples of the alkyl group having 1 to 5 carbon atoms include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, pentyl group, isopentyl group, Or a neopentyl group is mentioned. The alkyl group having 1 to 5 carbon atoms may have one or more substituents. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, and a cyano group.

  The alkyl group having 1 to 4 carbon atoms is linear or branched and unsubstituted. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an s-butyl group, and a t-butyl group. The alkyl group having 1 to 4 carbon atoms may have one or more substituents. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, and a cyano group.

  The alkyl group having 1 to 3 carbon atoms is linear or branched and unsubstituted. Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. The alkyl group having 1 to 3 carbon atoms may have one or more substituents. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, and a cyano group.

  The alkenyl group having 2 to 6 carbon atoms is linear or branched and unsubstituted. Examples of the alkenyl group having 2 to 6 carbon atoms include an ethenyl group, a propenyl group, a butenyl group, a pentenyl group, and a hexenyl group. The alkenyl group having 2 to 6 carbon atoms may have one or more substituents. Examples of such a substituent include an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, and a cyano 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 a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an s-butoxy group, a t-butoxy group, a pentyloxy group, an iso group. Examples thereof include a pentyloxy group, a neopentyloxy group, and a hexyloxy group. The alkoxy group having 1 to 6 carbon atoms may have one or more substituents. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, and a cyano group.

  Examples of the aryl group having 6 to 14 carbon atoms include an unsubstituted aromatic monocyclic hydrocarbon group having 6 to 14 carbon atoms and an unsubstituted aromatic condensed bicyclic carbon group having 6 to 14 carbon atoms. A hydrogen group or an unsubstituted aromatic condensed tricyclic hydrocarbon group having 6 to 14 carbon atoms. Examples of the aryl group having 6 to 14 carbon atoms include a phenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. The aryl group having 6 to 14 carbon atoms may have one or more substituents. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, or 6 or more carbon atoms. Examples include 14 or less aryl groups.

  An aryloxy group having 6 to 14 carbon atoms is unsubstituted. An aryloxy group having 6 to 14 carbon atoms is a group in which an aryl group having 6 to 14 carbon atoms and an oxygen atom are bonded. The aryloxy group having 6 to 14 carbon atoms may have one or more substituents. Examples of such a substituent include, for example, a halogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, or the number of carbon atoms. Examples include 6 or more and 14 or less aryl groups.

  An aralkyl group having 7 to 20 carbon atoms is unsubstituted. The aralkyl group having 7 to 20 carbon atoms is a group in which an aryl group having 6 to 14 carbon atoms and an alkyl group having 1 to 6 carbon atoms are bonded. The alkyl group having 1 to 6 carbon atoms in the aralkyl group having 7 to 20 carbon atoms is linear or branched and unsubstituted. Examples of the aralkyl group having 7 to 20 carbon atoms include phenylmethyl group (benzyl group), 2-phenylethyl group (phenethyl group), 1-phenylethyl group, 3-phenylpropyl group, and 4-phenylbutyl. Groups. The aralkyl group having 7 to 20 carbon atoms may have one or more substituents. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, or 6 or more carbon atoms. Examples include 14 or less aryl groups.

  An aralkyl group having 7 to 10 carbon atoms is unsubstituted. The aralkyl group having 7 to 10 carbon atoms is a group in which a phenyl group and an alkyl group having 1 to 4 carbon atoms are bonded. The alkyl group having 1 to 4 carbon atoms in the aralkyl group having 7 to 10 carbon atoms is linear or branched and unsubstituted. Examples of the aralkyl group having 7 to 10 carbon atoms include phenylmethyl group (benzyl group), 2-phenylethyl group (phenethyl group), 1-phenylethyl group, and 3-phenylpropyl group. The aralkyl group having 7 to 20 carbon atoms may have one or more substituents. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, or 6 or more carbon atoms. Examples include 14 or less aryl groups.

  An aralkyloxy group having 7 to 20 carbon atoms is unsubstituted. An aralkyloxy group having 7 to 20 carbon atoms is a group in which an aralkyl group having 7 to 20 carbon atoms and an oxygen atom are bonded. The oxygen atom is bonded to an alkyl group having 1 to 6 carbon atoms in the aralkyl group having 7 to 20 carbon atoms. Examples of the aralkyloxy group having 7 to 20 carbon atoms include a phenylmethyloxy group, a 2-phenylethyloxy group, a 1-phenylethyloxy group, a 3-phenylpropyloxy group, and a 4-phenylbutyloxy group. Can be mentioned. The aralkyloxy group having 7 to 20 carbon atoms may have one or more substituents. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, or 6 or more carbon atoms. Examples include 14 or less aryl groups.

  An aralkyloxy group having 7 to 10 carbon atoms is unsubstituted. An aralkyloxy group having 7 to 10 carbon atoms is a group in which an aralkyl group having 7 to 10 carbon atoms and an oxygen atom are bonded. The oxygen atom is bonded to an alkyl group having 1 to 3 carbon atoms in the aralkyl group having 7 to 10 carbon atoms. Examples of the aralkyloxy group having 7 to 10 carbon atoms include a phenylmethyloxy group, a 2-phenylethyloxy group, a 1-phenylethyloxy group, and a 3-phenylpropyloxy group. The aralkyloxy group having 7 to 10 carbon atoms may have one or more substituents. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, or 6 or more carbon atoms. Examples include 14 or less aryl groups.

  A heterocyclic group having 3 to 14 carbon atoms is unsubstituted. Examples of the heterocyclic group having 3 to 14 carbon atoms include a 5- or 6-membered monocyclic heterocyclic ring containing 1 or more (preferably 1 or more and 3 or less) heteroatoms and having aromaticity. A heterocyclic group in which such monocycles are condensed; or a heterocyclic group in which such a single ring is condensed with a 5-membered or 6-membered hydrocarbon ring. The hetero atom is at least one selected from the group consisting of a nitrogen atom, a sulfur atom, and an oxygen atom. Examples of the heterocyclic group having 3 to 14 carbon atoms include, for example, thiophenyl group, furanyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, isothiazolyl group, isoxazolyl group, oxazolyl group, isoxazolyl group, thiazolyl group, isothiazolyl group, and flazanil. Group, pyranyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, indolyl group, 1H-indazolyl group, isoindolyl group, chromenyl group, quinolinyl group, isoquinolinyl group, purinyl group, pteridinyl group, triazolyl group, tetrazolyl group, 4H -Quinolidinyl group, naphthyridinyl group, benzofuranyl group, 1,3-benzodioxolyl group, benzoxazolyl group, benzothiazolyl group, or benzimidazolyl group. The heterocyclic group having 3 to 14 carbon atoms may have one or more substituents. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, or 6 or more carbon atoms. Examples include 14 or less aryl groups.

  A cycloalkylidene group having 5 to 7 carbon atoms is unsubstituted. Examples of the cycloalkylidene group having 5 to 7 carbon atoms include a cyclopentylidene group, a cyclohexylidene group, and a cycloheptylidene group. The cycloalkylidene group having 5 to 7 carbon atoms may have one or more substituents. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, and a cyano group.

  An amino group is unsubstituted. The amino group may have a substituent. Examples of such a substituent include an alkyl group having 1 to 6 carbon atoms.

<First embodiment: electrophotographic photoreceptor>
[1. Photoconductor]
The first embodiment of the present invention relates to a single layer type electrophotographic photosensitive member (hereinafter sometimes referred to as a photosensitive member). Hereinafter, the structure of the photoreceptor will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view showing an example of a photoreceptor 1 according to the first embodiment.

  As shown in FIG. 1A, the photoreceptor 1 includes a conductive substrate 2 and a photosensitive layer 3. The photoreceptor 1 includes a single-layer type photosensitive layer 3 a as the photosensitive layer 3. The single layer type photosensitive layer 3 a is a single photosensitive layer 3. As shown in FIG. 1A, the photosensitive layer 3 may be disposed directly on the conductive substrate 2.

  As shown in FIG. 1B, the photoreceptor 1 may include a conductive substrate 2, a single-layer type photosensitive layer 3a, and an intermediate layer (undercoat layer) 4. The intermediate layer 4 is provided between the conductive substrate 2 and the single-layer type photosensitive layer 3a. As shown in FIG. 1B, the photosensitive layer 3 may be indirectly disposed on the conductive substrate 2 through the intermediate layer 4. Moreover, as shown in FIG.1 (c), the protective layer 5 may be provided on the single layer type photosensitive layer 3a.

  The thickness of the single-layer type photosensitive layer 3a is not particularly limited as long as the function as a single-layer type photosensitive layer can be sufficiently expressed. The thickness of the single-layer type photosensitive layer 3a is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less.

  The photosensitive layer includes a charge generating agent, a hole transporting agent, an electron transporting agent, a binder resin, an n-type pigment, and filler particles. The photosensitive layer may further contain an additive. The charge generating agent includes a phthalocyanine pigment. The content of the n-type pigment is 0.03 parts by mass or more and 3 parts by mass or less with respect to 1 part by mass of the phthalocyanine pigment.

  The photoconductor according to the first embodiment suppresses the generation of a transfer memory. The reason is presumed as follows. In the photoreceptor according to the first embodiment, the photosensitive layer includes a charge generating agent and an n-type pigment. The charge generating agent includes a phthalocyanine pigment. The content of the n-type pigment is 0.03 parts by mass or more and 3 parts by mass or less with respect to 1 part by mass of the phthalocyanine pigment. For this reason, the photosensitive layer tends to efficiently generate electrons as carriers and easily donates electrons to the electron transport agent. Therefore, the photosensitive layer has an excellent electron transport ability, and the carrier tends to hardly remain in the photosensitive layer. From the above, it is considered that the photoconductor according to the first embodiment suppresses the generation of the transfer memory. A method for evaluating the transfer memory will be described later in detail in Examples.

  Further, the photoreceptor according to the first embodiment is excellent in filming resistance. The reason is presumed as follows. For convenience, first, image defects due to filming in the image forming process 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, a transfer unit, and a cleaning unit. When the image forming process adopts a direct transfer method, the transfer unit transfers the toner image from the photoreceptor to the recording medium. After the transfer, the cleaning unit cleans the surface of the photosensitive layer 3.

  In the transfer of the toner image, the recording medium may be rubbed on the surface of the photoreceptor, and the recording medium may be charged (so-called frictional charging). In such a case, the recording medium tends to be charged to the same polarity as the charged polarity of the photoconductor and the chargeability tends to decrease, or tends to be charged to the opposite polarity (so-called reverse charging). When the recording medium has such a charging property, a minute component (for example, paper powder) included in the recording medium may move and adhere to the surface of the photoreceptor. If the cleaning unit cannot completely remove the minute components attached to the image area on the surface of the photoconductor, a defect may occur in the image formed on the recording medium. Such an image defect is called filming. The filming resistance evaluation method will be described later in detail in Examples.

  In the photoreceptor according to the first embodiment, the photosensitive layer includes filler particles. For this reason, the photosensitive layer tends to form an uneven shape on its surface, and the contact area between the surface of the photosensitive layer and a minute component tends to be small. When the contact area is small, the cleaning unit can easily remove minute components from the photosensitive layer. From the above, it is considered that the photoconductor according to the first embodiment is excellent in filming resistance.

  Hereinafter, a conductive substrate, an electron transport agent, a hole transport agent, a charge generator, a binder resin, an n-type pigment, filler particles, an additive, and an intermediate layer will be described as elements of the photoreceptor. In addition, a method for manufacturing the photoreceptor will be described.

[2. Conductive substrate]
The conductive substrate is not particularly limited as long as it can be used as the conductive substrate of the photoreceptor. The conductive substrate may be formed of a material having at least a surface portion having conductivity. An example of the conductive substrate is a conductive substrate formed of a conductive material. Another example of the conductive substrate is a conductive substrate coated with a conductive material. Examples of the conductive material include aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, and indium. These materials having conductivity may be used alone or in combination of two or more. Examples of the combination of two or more include alloys (more specifically, aluminum alloy, stainless steel, brass, etc.). Among these materials having conductivity, aluminum or an aluminum alloy is preferable because charge transfer from the photosensitive layer to the conductive substrate is good. Further, the conductive substrate may have an oxide film of the conductive material on the surface thereof.

  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 or a drum shape. The thickness of the conductive substrate is appropriately selected according to the shape of the conductive substrate.

[3. Electron transport agent]
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.

  Among these electron transport agents, compounds represented by general formula (ETM1), general formula (ETM2), general formula (ETM3), general formula (ETM4), and general formula (ETM5) (hereinafter referred to as electron transport agents (each ETM1) to (ETM5) may be included.

In General Formula (ETM1), R ⁶¹ , R ⁶² , R ⁶³ , and R ⁶⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms that may have a substituent, or a substituent. C1-C6 alkoxy group which may have, C6-C14 aryl group which may have a substituent, or C7-C20 which may have a substituent The following aralkyl groups are represented. R ⁶¹ , R ⁶² , R ⁶³ , and R ⁶⁴ may be the same as or different from each other. In General Formula (ETM1), R ⁶¹ , R ⁶² , R ⁶³ , and R ⁶⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and a hydrogen atom or 1 to 5 carbon atoms. It is preferable to represent the following alkyl groups, and it is preferable to represent a hydrogen atom or a 2-methyl-2-butyl group. Examples of the electron transfer agent (ETM1) include a compound represented by the chemical formula (ETM1-1) (hereinafter sometimes referred to as an electron transfer agent (ETM1-1)).

In General Formula (ETM2), R ³³ , R ³⁴ , R ³⁵ , and R ³⁶ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms that may have a substituent, or a substituent. An alkenyl group having 2 to 6 carbon atoms which may have, an alkoxy group having 1 to 6 carbon atoms which may have a substituent, and 6 to 14 carbon atoms which may have a substituent. An aryl group of the above, an aralkyl group having 7 to 20 carbon atoms which may have a substituent, or a heterocyclic group having 3 to 14 carbon atoms which may have a substituent. In the general formula (ETM2), R ³³ , R ³⁴ , R ³⁵ , and R ³⁶ preferably represent an alkyl group having 1 to 6 carbon atoms, and represent an alkyl group having 1 to 4 carbon atoms. Is more preferable, and it is more preferable to represent a methyl group or t-butyl group. Examples of the electron transport agent (ETM2) include a compound represented by the chemical formula (ETM2-1) (hereinafter sometimes referred to as an electron transport agent (ETM2-1)).

In General Formula (ETM3), R ⁶⁵ represents an alkyl group having 1 to 6 carbon atoms which may have a substituent or an aryl group having 6 to 14 carbon atoms which may have a substituent. . R ⁶⁶ represents an alkyl group having 1 to 6 carbon atoms which may have a substituent, an aryl group having 6 to 14 carbon atoms which may have a substituent, and the number of carbon atoms which may have a substituent. Represents an alkoxy group having 1 to 6 carbon atoms, an aryloxy group having 6 to 14 carbon atoms which may have a substituent, or an aralkyloxy group having 7 to 20 carbon atoms which may have a substituent. . R ⁶⁷ represents an alkyl group having 1 to 6 carbon atoms which may have a substituent. s represents an integer of 0 or more and 4 or less. R ⁶⁵ , R ⁶⁶ , and R ⁶⁷ may be the same as or different from each other.
In general formula (ETM3), R ₆₅ preferably represents an aryl group having 6 to 14 carbon atoms, and more preferably a phenyl group. R ⁶⁶ preferably represents an aralkyloxy group having 7 to 20 carbon atoms, more preferably an aralkyloxy group having 7 to 10 carbon atoms, and still more preferably a phenylmethyloxy group. It is preferable that s represents 0. Examples of the electron transfer agent (ETM3) include a compound represented by the chemical formula (ETM3-1) (hereinafter sometimes referred to as an electron transfer agent (ETM3-1)).

In General Formula (ETM4), R ³⁹ and R ⁴⁰ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms that may have one or more substituents, and a substituent. It represents an optionally substituted alkoxy group having 1 to 20 carbon atoms, an optionally substituted aryl group having 6 to 14 carbon atoms, and an optionally substituted amino group. R ³⁹ and R ⁴⁰ may be the same as or different from each other. In General Formula (ETM4), R ³⁹ and R ⁴⁰ represent an aryl group having 6 to 14 carbon atoms which may have one or more alkyl groups having 1 to 6 carbon atoms, and a plurality of carbons It preferably represents a phenyl group having an alkyl group having 1 or more and 3 or less atoms, and more preferably represents an ethylmethylphenyl group. Examples of the electron transfer agent (ETM4) include a compound represented by the chemical formula (ETM4-1) (hereinafter sometimes referred to as an electron transfer agent (ETM4-1)).

In the general formula (ETM5), R ⁴¹ , R ⁴² and R ⁴³ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or a substituent. An alkenyl group having 2 to 6 carbon atoms which may have, an alkoxy group having 1 to 6 carbon atoms which may have a substituent, and 6 to 14 carbon atoms which may have a substituent. An aryl group of the above, an aralkyl group having 7 to 20 carbon atoms which may have a substituent, or a heterocyclic group having 3 to 14 carbon atoms which may have a substituent. R ⁴¹ , R ⁴² , and R ⁴³ may be the same as or different from each other. In the general formula (ETM5), R ⁴¹ , R ⁴² , and R ⁴³ represent an aryl group having 6 to 14 carbon atoms or an alkyl group having 1 to 6 carbon atoms, which may have a halogen atom. It is more preferable that it represents a phenyl group having a halogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably a chlorophenyl group or a t-butyl group. Examples of the electron transfer agent (ETM5) include a compound represented by the chemical formula (ETM5-1) (hereinafter sometimes referred to as an electron transfer agent (ETM5-1)).

  Among these electron transfer agents, from the viewpoint of further suppressing the generation of transfer memory, electron transfer agents (ETM1) to (ETM5) are preferable, and electron transfer agents (ETM1) and (ETM4) to (ETM5) are more preferable. From the viewpoint of further improving the filming resistance of the photoreceptor, electron transfer agents (ETM1) to (ETM5) are preferable, and an electron transfer agent (ETM1) is more preferable. Among these electron transport agents, from the viewpoint of further improving the filming resistance of the photoreceptor and further suppressing the generation of the transfer memory, electron transport agents (ETM1) to (ETM5) are preferable, and the electron transport agent (ETM1) is preferred. ) And (ETM4) to (ETM5) are more preferable.

[4. Hole transport agent]
As the hole transport agent, for example, a nitrogen-containing cyclic compound or a condensed polycyclic compound can be used. Examples of the nitrogen-containing cyclic compound and the condensed polycyclic compound include diamine derivatives (more specifically, N, N, N ′, N′-tetraphenylphenylenediamine derivatives, N, N, N ′, N ′). -Tetraphenylnaphthylenediamine derivative, or N, N, N ', N'-tetraphenylphenanthrylenediamine derivative, etc.), oxadiazole compounds (more specifically, 2,5-di (4-methyl) Aminophenyl) -1,3,4-oxadiazole, etc.), styryl compounds (more specifically, 9- (4-diethylaminostyryl) anthracene, etc.), carbazole compounds (more specifically, polyvinylcarbazole, etc.) Organic polysilane compounds, pyrazoline compounds (more specifically, 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline, etc.), hydrazo System compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, or triazole compound. These hole transport agents may be used alone or in combination of two or more.

  Among these hole transport agents, general formula (HTM1), general formula (HTM2), general formula (HTM3), general formula (HTM4), general formula (HTM5), general formula (HTM6), or general formula (HTM7) ) (Hereinafter may be referred to as hole transporting agents (HTM1) to (HTM7)).

In general formula (HTM1), Q ⁸ , Q ¹⁰ , Q ¹¹ , Q ¹² , Q ¹³ , and Q ¹⁴ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or 1 or more carbon atoms. 6 or less alkoxy group or a phenyl group is represented. Q ⁹ and Q ¹⁵ each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. b represents an integer of 0 or more and 5 or less, and when b represents an integer of 2 or more and 5 or less, a plurality of Q ⁹ bonded to the same phenyl group may be the same or different. c represents an integer of 0 or more and 4 or less, and when c represents an integer of 2 or more and 4 or less, a plurality of Q ¹⁵ bonded to the same phenyl group may be the same or different from each other. k represents 0 or 1.

In general formula (HTM1), Q ⁸ , Q ¹⁰ , Q ¹¹ , Q ¹² , Q ¹³ , and Q ¹⁴ preferably represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. It is more preferable to represent a group or an ethyl group. b and c preferably represent 0. k preferably represents 0. Examples of the hole transporting agent (HTM1) include a compound represented by the chemical formula (HTM1-1) (hereinafter sometimes referred to as a hole transporting agent (HTM1-1)).

In General Formula (HTM2), Q ¹ has a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms. It may represent a phenyl group which may be. Q ² represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. Q ³ , Q ⁴ , Q ⁵ , Q ⁶ , and Q ⁷ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. Represent. Two adjacent ones of Q ³ , Q ⁴ , Q ⁵ , Q ⁶ , and Q ⁷ may be bonded to each other to form a ring. a represents an integer of 0 or more and 5 or less. When a represents an integer of 2 or more and 5 or less, a plurality of Q ² bonded to the same phenyl group may be the same or different from each other. t and u each independently represents an integer of 0 or more and 2 or less.

In general formula (HTM2), Q ¹ preferably represents a hydrogen atom. Q ³ , Q ⁴ , Q ⁵ , Q ⁶ , and Q ⁷ each independently preferably represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and each represents a hydrogen atom or an n-butyl group. Is more preferable. It is preferable that t and u represent 1. Examples of the hole transporting agent (HTM2) include a compound represented by the chemical formula (HTM2-1) (hereinafter sometimes referred to as a hole transporting agent (HTM2-1)).

In the general formula (HTM3), Q ¹⁶ , Q ¹⁷ , Q ¹⁸ , and Q ¹⁹ each independently represent an alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an n-butyl group. . Examples of the hole transporting agent (HTM3) include a compound represented by the chemical formula (HTM3-1) (hereinafter sometimes referred to as a hole transporting agent (HTM3-1)).

In general formula (HTM4), Q ²⁰ , Q ²¹ , Q ²² , and Q ²³ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and may represent a hydrogen atom or a methyl group. preferable. Examples of the hole transporting agent (HTM4) include a compound represented by the chemical formula (HTM4-1) (hereinafter sometimes referred to as a hole transporting agent (HTM4-1)).

In General Formula (HTM5), R ^d , R ^e , and R ^f each independently represents an alkyl group having 1 to 6 carbon atoms. o, p, and r each independently represent an integer of 0 or more and 5 or less. When o represents an integer of 2 or more and 4 or less, a plurality of R ^e bonded to the same phenyl group may be the same or different. When p represents an integer of 2 or more and 4 or less, a plurality of R ^f bonded to the same phenyl group may be the same or different from each other. When r represents an integer of 2 or more and 4 or less, a plurality of R ^d bonded to the same phenyl group may be the same or different from each other.

In general formula (HTM5), R ^e preferably represents an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group or an ethyl group. o preferably represents 2. p and r preferably represent 0. Examples of the hole transporting agent (HTM5) include a compound represented by the chemical formula (HTM5-1) (hereinafter sometimes referred to as a hole transporting agent (HTM5-1)).

In general formula (HTM6), R ^a , R ^b , and R ^c each independently represents an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an alkoxy group having 1 to 6 carbon atoms. q represents an integer of 0 or more and 4 or less, and when q represents an integer of 2 or more and 4 or less, a plurality of R ^c bonded to the same phenyl group may be the same or different from each other. m and n each independently represent an integer of 0 or more and 5 or less. When m represents an integer of 2 or more and 5 or less, a plurality of R ^b bonded to the same phenyl group may be the same or different from each other. When n represents an integer of 2 or more and 5 or less, a plurality of R ^a bonded to the same phenyl group may be the same or different from each other.

In general formula (HTM6), R ^b and R ^c are each independently preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. It is preferable that m and n each independently represent 1 or 2. q preferably represents 0. Examples of the hole transporting agent (HTM6) include a compound represented by the chemical formula (HTM6-1) (hereinafter sometimes referred to as a hole transporting agent (HTM6-1)).

In the general formula (HTM7), Q ³¹ , Q ³³ , and Q ³⁵ each independently represent an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. . d, e, and f each independently represent an integer of 0 or more and 5 or less. Q ³² , Q ³⁴ , and Q ³⁶ 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 an alkyl having 1 to 6 carbon atoms Represents a phenyl group which may be substituted with a group. g, h, and i each independently represents 0 or 1;

In the general formula (HTM7), Q ³¹ , Q ³³ , and Q ³⁵ preferably represent an alkyl group having 1 to 3 carbon atoms, and more preferably represent a methyl group. d, e, and f preferably represent 1. Q ³² , Q ³⁴ , and Q ³⁶ preferably represent a hydrogen atom. g, h, and i preferably represent 0. Examples of the hole transporting agent (HTM7) include a compound represented by the chemical formula (HTM7-1) (hereinafter sometimes referred to as a hole transporting agent (HTM7-1)).

  Among these hole transport agents, from the viewpoint of further improving the filming resistance of the photoreceptor, hole transport agents (HTM1) to (HTM7) are preferable, and hole transport agents (HTM1) to (HTM4) are more preferable. A hole transfer agent (HTM1) is more preferable. Further, from the viewpoint of further suppressing the generation of transfer memory, hole transport agents (HTM1) to (HTM7) are preferable, hole transport agents (HTM1) to (HTM3) and (HTM5) to (HTM7) are more preferable, A hole transport agent (HTM7) is more preferable. Of these hole transport agents, hole transport agents (HTM1) to (HTM7) are preferred from the viewpoint of further improving the filming resistance of the photoreceptor and suppressing the generation of transfer memory. The transport agents (HTM1) to (HTM3) are more preferable.

  When the photoreceptor is a single layer type photoreceptor, the content of the hole transport agent is 10 parts by mass or more and 300 parts by mass or less with respect to 100 parts by mass of the binder resin contained in the single layer type photosensitive layer. Is more preferably 10 parts by mass or more and 200 parts by mass or less, and particularly preferably 10 parts by mass or more and 100 parts by mass or less.

[5. Charge generator]
The charge generator is a phthalocyanine pigment. Examples of the phthalocyanine pigment include titanyl phthalocyanine represented by the chemical formula (CGM-A) (hereinafter sometimes referred to as titanyl phthalocyanine (CGM-A)) or metal phthalocyanine. Examples of the metal phthalocyanine include metal-free phthalocyanine, hydroxygallium phthalocyanine, or chlorogallium phthalocyanine represented by the chemical formula (CGM-B). The phthalocyanine pigment may be crystalline or non-crystalline. The crystal shape of the phthalocyanine pigment (for example, X-type, α-type, β-type, Y-type, V-type, or II-type) is not particularly limited, and phthalocyanine pigments having various crystal shapes are used.

  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 crystal of titanyl phthalocyanine include α-type, β-type, or Y-type crystal of titanyl phthalocyanine (hereinafter referred to as α-type titanyl phthalocyanine crystal, β-type titanyl phthalocyanine crystal, and Y-type titanyl phthalocyanine crystal, respectively). ). Examples of the crystal of hydroxygallium phthalocyanine include a V-type crystal of hydroxygallium phthalocyanine. Examples of chlorogallium phthalocyanine crystals include chlorogallium phthalocyanine type II crystals.

  For example, in a digital optical image forming apparatus (for example, a laser beam printer or a facsimile using a light source such as a semiconductor laser), it is preferable to use a photoreceptor having sensitivity in a wavelength region of 700 nm or more. Since it has a high quantum yield in a wavelength region of 700 nm or more, the charge generator is preferably a phthalocyanine pigment, more preferably a metal-free phthalocyanine or titanyl phthalocyanine. In order to further improve the filming resistance of the photoreceptor when the photosensitive layer contains an n-type pigment and filler particles, X-type metal-free phthalocyanine, α-type titanyl phthalocyanine crystal, or Y-type titanyl phthalocyanine crystal is preferable. More preferred are type-free metal phthalocyanine or Y-type titanyl phthalocyanine crystals. In order to further improve the filming resistance of the photoreceptor when the photosensitive layer contains an n-type pigment and filler particles, X-type metal-free phthalocyanine, α-type titanyl phthalocyanine crystal, or Y-type titanyl phthalocyanine crystal is preferable. Type-free metal phthalocyanine or Y-type titanyl phthalocyanine crystal is more preferable, and Y-type titanyl phthalocyanine crystal is more preferable. In order to further suppress the generation of transfer memory when the photosensitive layer contains n-type pigment and filler particles, X-type metal-free phthalocyanine, α-type titanyl phthalocyanine crystal, or Y-type titanyl phthalocyanine crystal is preferable, and Y-type titanyl phthalocyanine Crystals are more preferred.

  The Y-type titanyl phthalocyanine crystal preferably has a main peak at 27.2 ° with a Bragg angle 2θ ± 0.2 ° in the CuKα characteristic X-ray diffraction spectrum. The main peak in the CuKα characteristic X-ray diffraction spectrum is a peak having the first or second highest intensity in a range where the Bragg angle (2θ ± 0.2 °) is 3 ° or more and 40 ° or less.

  The α-type titanyl phthalocyanine crystal has a main peak at 28.6 ° with a Bragg angle 2θ ± 0.2 °, for example, in the CuKα characteristic X-ray diffraction spectrum.

(Measuring method of CuKα characteristic X-ray diffraction spectrum)
A method for measuring the CuKα characteristic X-ray diffraction spectrum will be described. A sample (titanyl phthalocyanine) is filled in a sample holder of an X-ray diffractometer (“RINT (registered trademark) 1100” manufactured by Rigaku Corporation), an X-ray tube Cu, a tube voltage 40 kV, a tube current 30 mA, and a CuKα characteristic X An X-ray diffraction spectrum is measured under the condition of a line wavelength of 1.542 mm. The measurement range (2θ) is 3 ° to 40 ° (start angle 3 °, stop angle 40 °), and the scanning speed is, for example, 10 ° / min. The main peak is determined from the obtained X-ray diffraction spectrum, and the Bragg angle of the main peak is read.

The Y-type titanyl phthalocyanine crystal preferably has the following characteristic (a) or characteristic (b).
Characteristic (a): In the differential scanning calorimetry, it has no peak in the range of 50 ° C. or higher and 400 ° C. or lower except for the peak accompanying the vaporization of adsorbed water.
Characteristic (b): In differential scanning calorimetry, except for the peak accompanying vaporization of adsorbed water, there is no peak in the range of 50 ° C. or more and less than 270 ° C. and 1 in the range of 270 ° C. or more and 400 ° C. or less. Having two peaks.

(Differential calorimetric spectrum measurement method)
A method for measuring the differential calorimetric spectrum will be described. A sample for evaluation of crystal powder is placed on a sample pan, and a differential scanning calorimetry spectrum is measured using a differential scanning calorimeter (“TAS-200 DSC8230D” manufactured by Rigaku Corporation). The measurement range is 40 ° C. or higher and 400 ° C. or lower, and the temperature rising rate is 20 ° C./min.

(Method for preparing Y-type titanyl phthalocyanine crystal)
The method for preparing Y-type titanyl phthalocyanine crystal includes, for example, a synthesis step, a pre-pigmentation step, and a pigmentation step.

(Synthesis process)
In the synthesis step, titanyl phthalocyanine is synthesized. Examples of the method for synthesizing titanyl phthalocyanine include a reaction represented by reaction formula (R-1) or a reaction represented by reaction formula (R-2) (hereinafter, reactions (R-1) and (R-2)). May be described). In reaction (R-1), phthalonitrile (21a) and titanium alkoxide (21b) are reacted to synthesize titanyl phthalocyanine (CGM-A).

  1,3-diiminoisoindoline (21c) is reacted with titanium alkoxide (21b) to synthesize titanyl phthalocyanine (CGM-A).

(Pre-pigmentation process)
In the pre-pigmentation treatment step, a stirring treatment and a stationary treatment are performed to stabilize titanyl phthalocyanine (CGM-A). In the stirring treatment, titanyl phthalocyanine (CGM-A) is added to a water-soluble organic solvent to prepare a solution. The solution is stirred for a certain time while the solution is heated. The heating temperature is preferably 70 ° C. or higher and 200 ° C. or lower. The stirring time is preferably 1 hour or more and 3 hours or less. In the standing treatment, the solution is allowed to stand for stabilization for a certain period of time at a low temperature. The low temperature indicates a temperature lower than the temperature in the stirring process. The low temperature is preferably 10 ° C. or more and 50 ° C. or less, and more preferably room temperature (for example, 23 ° C.). The standing time is preferably 5 hours or more and 10 hours or less. By removing the water-soluble organic solvent, a crude crystal of titanyl phthalocyanine (CGM-A) is obtained.

  Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, N, N-dimethylformamide, N, N-dimethylacetamide, propionic acid, acetic acid, N-methylpyrrolidone, or ethylene glycol. One of these water-soluble organic solvents may be used alone, or two or more thereof may be used in combination.

(Pigmentation process)
In the pigmentation step, titanyl phthalocyanine is pigmented. An example of the pigmentation process will be described. A crude crystal of titanyl phthalocyanine (CGM-A) is dissolved in a solvent to prepare a titanyl phthalocyanine solution. This solution is dropped into a poor solvent and recrystallized. Subsequently, it is pigmented through processes such as filtration, washing with water, milling, filtration, and drying. As a result, a Y-type titanyl phthalocyanine crystal is obtained.

  Examples of the solvent that dissolves the crude crystals include dichloromethane, chloroform, ethyl bromide, butyl bromide, trifluoroacetic acid, trichloroacetic acid, tribromoacetic acid, and sulfuric acid. These solvent may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the poor solvent for recrystallization include water, methanol, ethanol, isopropanol, acetone, and dioxane. These poor solvents may be used alone or in combination of two or more.

  The milling process is a process of dispersing and stirring in a non-aqueous solvent in a state where water is present without drying the solid after washing with water. Examples of non-aqueous solvents for milling include halogen solvents (more specifically, chlorobenzene, dichloromethane, etc.).

  Another example of the pigmentation process will be described. The crude crystal of titanyl phthalocyanine (CGM-A) is processed by the acid paste method. Specifically, an acid solution is prepared by dissolving crude crystals in an acid. The acid solution is dropped into water under ice cooling and stirred for a certain time. Subsequently, it is recrystallized by standing at room temperature (for example, 23 ° C.). As a result, low crystalline titanyl phthalocyanine is obtained. Examples of the acid used in the acid paste method include concentrated sulfuric acid or sulfonic acid.

  Low crystalline titanyl phthalocyanine is filtered and washed with water. Next, in a state where water is present without drying, a low crystalline titanyl phthalocyanine is dispersed in a non-aqueous solvent, and a milling process is performed. Filtration is performed after milling to obtain a filtrate (solid). When the filtrate is dried, Y-type titanyl phthalocyanine crystals are obtained.

  The charge generating agent may contain another charge generating agent other than the phthalocyanine pigment. Other charge generators include, for example, perylene pigments, bisazo pigments, trisazo pigments, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, indigo pigments, azulenium pigments, cyanine pigments, inorganic pigments Powders of photoconductive materials (more specifically, selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, amorphous silicon, etc.), pyrylium pigment, ansanthrone pigment, triphenylmethane pigment, selenium pigment, toluidine pigment, pyrazoline Examples thereof include pigments and quinacridone pigments. Another charge generating agent may be used alone or in combination of two or more.

  An santhrone pigment is preferably used as a charge generating agent in a photoreceptor applied to an image forming apparatus using a short wavelength laser light source. The wavelength of the short wavelength laser light is, for example, not less than 350 nm and not more than 550 nm.

  When the photoreceptor is a single layer type photoreceptor, the content of the charge generating agent is 0.1 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the binder resin contained in the single layer type photosensitive layer. It is preferably 0.5 parts by mass or more and 30 parts by mass or less, and more preferably 0.5 parts by mass or more and 6 parts by mass or less.

[6. Binder resin]
Examples of the binder resin include a thermoplastic resin, a thermosetting resin, and a photocurable resin. Examples of the thermoplastic resin include polycarbonate resin, polyarylate resin, styrene-butadiene resin, styrene-acrylonitrile resin, styrene-maleic acid resin, acrylic acid resin, styrene-acrylic acid resin, polyethylene resin, and ethylene-vinyl acetate resin. , Chlorinated polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer resin, vinyl chloride-vinyl acetate resin, alkyd resin, polyamide resin, urethane resin, polysulfone resin, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyester resin or A polyether resin is mentioned. As a thermosetting resin, a silicone resin, an epoxy resin, a phenol resin, a urea resin, or a melamine resin is mentioned, for example. Examples of the photocurable resin include an epoxy-acrylic acid resin (more specifically, an acrylic acid derivative adduct of an epoxy compound) or a urethane-acrylic resin (acrylic acid derivative adduct of a urethane compound). Can be mentioned. These binder resins may be used individually by 1 type, and may be used in combination of 2 or more type.

  Among these resins, a polycarbonate resin or a polyarylate resin is preferable because a photosensitive layer having a good balance of processability, mechanical properties, optical properties, and abrasion resistance can be obtained. Furthermore, from the viewpoint of good compatibility with the enamine derivative (1) and improvement in dispersibility of the enamine derivative (1) in the photosensitive layer, a polycarbonate resin having a repeating unit represented by the general formula (3) ( Hereinafter, a polyarylate resin having a repeating unit represented by the general formula (4) (hereinafter sometimes referred to as a polyarylate resin (4)) is more preferred. .

In general formula (3), R ¹¹ and R ¹² are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, or phenyl which may have a substituent. Represents a group. R ¹¹ and R ¹² may represent a cycloalkylidene group formed by bonding to each other. R ¹¹ and R ¹² may be the same as or different from each other. R ¹³ and R ¹⁴ each independently represents an alkyl group having 1 to 3 carbon atoms which may have a hydrogen atom or a halogen atom. R ¹³ and R ¹⁴ may be the same as or different from each other.

In the general formula (4), R ¹⁵ and R ¹⁶ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, or phenyl which may have a substituent. Represents a group. R ¹⁵ and R ¹⁶ may represent a cycloalkylidene group formed by bonding to each other. R ¹⁵ and R ¹⁶ may be the same as or different from each other. R ¹⁷ and R ¹⁸ each independently represents an alkyl group having 1 to 3 carbon atoms which may have a hydrogen atom or a halogen atom. R ¹⁷ and R ¹⁸ may be the same or different from each other. The substitution positions of the two carbonyl groups are in the ortho-position (o-position), meta- (m-position), or para-position (p-position) on the benzene ring having the two carbonyl groups.

In general formula (3), the alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ¹¹ and R ¹² is preferably an alkyl group having 1 to 4 carbon atoms, and a methyl group is More preferred. The cycloalkylidene group formed by combining R ¹¹ and R ¹² with each other is preferably a cycloalkylidene group having 5 to 7 carbon atoms, and more preferably a cyclohexylidene group. In general formula (3), R ¹¹ and R ¹² represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or a cycloalkylidene group having 5 to 7 carbon atoms formed by bonding to each other. Is preferably represented. More preferably, R ¹¹ and R ¹² represent a hydrogen atom or a methyl group, or represent a cyclohexylidene group formed by bonding to each other.

In general formula (3), the alkyl group having 1 to 3 carbon atoms which may have a halogen atom represented by R ¹³ and R ¹⁴ is preferably a methyl group which may have a halogen atom, A methyl fluoride group is more preferable, and a methyl group or a trifluoromethyl group is still more preferable. In the general formula (3), R ¹³ and R ¹⁴ preferably represent a hydrogen atom or a methyl group which may have a halogen atom, more preferably represent a hydrogen atom or a methyl fluoride group, a hydrogen atom or More preferably, it represents a trifluoromethyl group. R ¹³ and R ¹⁴ are preferably the same as each other. From the viewpoint of further improving the filming resistance of the photoreceptor, in general formula (3), at least one of R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ preferably has one or more halogen atoms. .

  As the polycarbonate resin (3), for example, a chemical formula (PC-1), a chemical formula (PC-2), a chemical formula (PC-3), a chemical formula (PC-4), or a repeating formula represented by a chemical formula (PC-5). Examples thereof include polycarbonate resins having units (hereinafter sometimes referred to as polycarbonate resins (PC-1) to (PC-5), respectively).

In general formula (4), the alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ¹⁵ and R ¹⁶ is preferably an alkyl group having 1 to 3 carbon atoms, and a methyl group is More preferred. The alkyl group having 1 to 3 carbon atoms which may have a halogen atom represented by R ¹⁷ and R ¹⁸ is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group.

In the general formula (4), R ¹⁵ and R ¹⁶ preferably represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably represent a hydrogen atom or a methyl group. R ¹⁵ and R ¹⁶ are preferably different from each other. R ¹⁷ and R ¹⁸ preferably represent an alkyl group having 1 to 3 carbon atoms, and more preferably represent a methyl group. R ¹⁷ and R ¹⁸ are preferably the same as each other. R ¹⁹ and R ²⁰ preferably represent a hydrogen atom. From the viewpoint of further improving the filming resistance of the photoreceptor, in general formula (4), at least one of R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ preferably has one or more halogen atoms. .

  Examples of the polyarylate resin (4) include a polyarylate resin having a repeating unit represented by the chemical formula (PAR-1) (hereinafter sometimes referred to as polyarylate resin (PAR-1)).

  When the photosensitive layer contains an n-type pigment and filler particles, the binder resin is preferably a polycarbonate resin (PC-1) to (PC-4) or a polyarylate resin (PAR-1). When the photosensitive layer contains an n-type pigment and filler particles, the binder resins are preferably polycarbonate resins (PC-1) to (PC-5) and polyarylate resins (PAR-1) from the viewpoint of further suppressing transfer memory. When the photosensitive layer contains an n-type pigment and filler particles, the binder resins are polycarbonate resins (PC-1) to (PC-5) and polyarylate resins (from the viewpoint of further improving the filming resistance of the photoreceptor). PAR-1) is preferred. When the photosensitive layer contains an n-type pigment and filler particles, the binder resins are polycarbonate resins (PC-1) to (PC) from the viewpoint of further improving the filming resistance of the photoreceptor and further suppressing the transfer memory. -5) and polyarylate resin (PAR-1) are preferred.

  The viscosity average molecular weight of the binder resin is preferably 20000 or more, more preferably 30000 or more and 70000 or less, and further preferably 48500 or more and 50000 or less. When the viscosity average molecular weight of the binder resin is 3000 or more, it is easy to improve the abrasion resistance of the photoreceptor. When the viscosity average molecular weight of the binder resin is 70000 or less, the binder resin is easily dissolved in a solvent during formation of the photosensitive layer, and the viscosity of the coating solution for the photosensitive layer does not become too high. As a result, it becomes easy to form a photosensitive layer.

[7. n-type pigment]
It is considered that the n-type pigment functions as a charge generation auxiliary agent and efficiently generates electrons as carriers. In addition, the n-type pigment may transfer electrons from the charge generating agent and donate electrons to the electron transport agent.

  Examples of n-type pigments include perylene pigments, azo pigments, polycyclic quinone pigments, squarylium pigments, pyranthrone pigments, perinone pigments, isoindoline pigments, quinacdrine pigments, pyrazolone pigments, or benzimidazolone pigments. Pigments. Among these n-type pigments, when the photosensitive layer contains filler particles, a perylene pigment or an azo pigment is preferable from the viewpoint of further improving the generation of transfer memory and further improving the filming resistance of the photoreceptor.

  The perylene pigment will be described. As a perylene pigment, the compound represented by general formula (PI) is mentioned, for example.

In general formula (PI), R ²¹ and R ²² each independently represent a hydrogen atom or a monovalent organic group.

In the general formula (PI), examples of the monovalent organic group represented by R ²¹ and R ²² include a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and a carbon atom that may have a substituent. Examples include an aralkyl group having 7 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms which may have a substituent, or a heterocyclic group having 3 to 14 carbon atoms which may have a substituent. It is done.

In general formula (PI), the alkyl group having 1 to 6 carbon atoms represented by R ²¹ and R ²² is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group.

In general formula (PI), the aryl group having 6 to 14 carbon atoms represented by R ²¹ and R ²² is preferably a phenyl group.

In general formula (PI), R ²¹ and R ²² represent an aralkyl group having 7 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms, or a heterocyclic group having 3 to 14 carbon atoms. May have a substituent. Examples of such a substituent include an alkyl group having 1 to 6 carbon atoms (preferably a methyl group), an alkoxy group having 1 to 6 carbon atoms, a phenyl group, and a halogen atom (preferably a chlorine atom). ), A hydroxyl group, a cyano group, or a nitro group. Examples of the phenyl group having a substituent include a 2,4-dimethylphenyl group and a 4-chlorophenyl group.

  Specific examples of suitable perylene pigments include compounds represented by chemical formulas (N6) to (N9) (hereinafter sometimes referred to as n-type pigments (N6) to (N9)).

  Next, the azo pigment will be described. The azo pigment is not particularly limited as long as it is a compound containing an azo group (—N═N—) in its structure.

  Examples of the azo pigment include monoazo pigments and polyazo pigments (more specifically, bisazo pigments, trisazo pigments, tetrakisazo pigments, etc.). The azo pigment may be a tautomer of a compound having an azo group. The compound having an azo group may be substituted with a chlorine atom.

  Examples of the azo pigment include known azo pigments. The azo pigment is preferably pigment yellow (more specifically, 14, 17, 49, 65, 73, 83, 93, 94, 95, 128, 166, or 77), pigment orange (more specifically, , 1, 2, 13, 34, or 36), or pigment red (more specifically, 30, 32, 61, or 144).

  Preferred specific examples of the azo pigment include a compound represented by the chemical formula (N1) (Pigment Yellow 128), a compound represented by the Chemical Formula (N2) (Pigment Yellow 93), and a compound represented by the Chemical Formula (N3) ( Pigment Orange 13) or a compound represented by Chemical Formula (N4) (Pigment Yellow 83). Hereinafter, the compounds represented by the chemical formulas (N1) to (N4) may be referred to as n-type pigments (N1) to (N4), respectively.

Specific examples of the pigment other than the perylene pigment and the azo pigment include a compound represented by the chemical formula (N5) (hereinafter sometimes referred to as an n-type pigment (N5)).

  The content of the n-type pigment is 0.03 to 3 parts by mass with respect to 1 part by mass of the phthalocyanine pigment.

  From the viewpoint of further improving the filming resistance of the photoreceptor and further suppressing the generation of transfer memory, the n-type pigment is a perylene pigment (more specifically, a perylene pigment (N6) to (N9) or the like) or An azo pigment (more specifically, an azo pigment (N1) to (N4) or the like) is preferable, and two or more selected from the group consisting of a perylene pigment and an azo pigment are more preferable.

  From the viewpoint of further improving the filming resistance of the photoreceptor and further suppressing the generation of transfer memory, compounds represented by perylene pigments (N1) to (N4), chemical formula (N5), or azo pigments (N6) To (N9) are preferred, and perylene pigments (N1) to (N4), azo pigments (N6), or azo pigments (N8) are more preferred.

  From the viewpoint of further suppressing the generation of transfer memory, perylene pigments (N1) to (N4), compounds represented by chemical formula (N5), or azo pigments (N6) to (N9) are preferable, and perylene pigments (N1) to (N4), an azo pigment (N6), or an azo pigment (N8) is more preferable.

  In addition to the n-type pigment, another pigment may be contained in the photosensitive layer as long as the effect is not impaired. Other pigments include, for example, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, indigo pigments, azulenium pigments, cyanine pigments, powders of inorganic photoconductive materials (more specifically, , Selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, amorphous silicon, etc.), pyrylium salt, ansanthrone pigment, triphenylmethane pigment, selenium pigment, toluidine pigment, pyrazoline pigment, or quinacridone pigment Is mentioned.

[8. Filler particles]
The filler particles are silica particles or resin particles. Examples of the resin of the resin particles include silicone resin, polyphenylene sulfide resin (hereinafter sometimes referred to as PFS resin), or polytetrafluoroethylene resin (hereinafter sometimes referred to as PTFE resin). . From the viewpoint of further suppressing the generation of the transfer memory, a silicone resin or a PTFE resin is preferable. The resin particles preferably contain a halogen atom (more specifically, a fluorine atom or the like). The filler particles preferably do not have conductivity. This is because if the filler particles have conductivity, it becomes difficult to uniformly charge the surface of the photosensitive layer.

The volume median diameter D ₅₀ of the filler particles is preferably from 5 nm to 10 μm, more preferably from 0.4 μm to 10 μm, from the viewpoint of further improving the filming resistance of the photoreceptor. More preferably, it is 0 μm or more and 10 μm or less. The volume median diameter D50 of the filler particles is measured using a precision particle size distribution measuring apparatus (“Coulter Counter Multitizer 3” manufactured by Beckman Coulter, Inc.). The volume median diameter D ₅₀ means the median diameter calculated by volume using a Coulter counter method.

  The content of the filler particles is preferably in the following range after satisfying that it is 0.03 parts by mass or more and 3 parts by mass or less with respect to 1 part by mass of the phthalocyanine pigment. The content of the filler particles is 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 in the photosensitive layer from the viewpoint of further suppressing the generation of the transfer memory. More preferably, it is 20 parts by mass or more. The content of the filler particles is 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 in the photosensitive layer from the viewpoint of further improving the filming resistance of the photoreceptor. It is more preferably 3 parts by mass or more and 20 parts by mass or less, and further preferably 3 parts by mass or more and 10 parts by mass or less. Further, the content of the filler particles is 0.5 parts by mass with respect to 100 parts by mass of the binder resin in the photosensitive layer from the viewpoint of further improving the filming resistance of the photoreceptor and further suppressing the generation of the transfer memory. The amount is preferably 30 parts by mass or less, and more preferably 3 parts by mass or more and 20 parts by mass or less.

[9. Additive]
The photosensitive layer may contain various additives as necessary. 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, donor, surfactant, plasticizer, sensitizer, or leveling agent may be mentioned.

[10. Middle layer]
The intermediate layer (undercoat layer) contains, for example, inorganic particles and a resin (intermediate layer resin). The presence of the intermediate layer is considered to suppress the increase in resistance by smoothing the flow of current generated when the photosensitive member is exposed while maintaining an insulating state capable of suppressing the occurrence of leakage.

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

  The resin for the intermediate layer is not particularly limited as long as it can be used as a resin for forming the intermediate layer. The intermediate layer may contain various additives. The additive is the same as the additive for the photosensitive layer.

[11. Photoconductor manufacturing method]
Next, the photoreceptor is produced, for example, by applying a photosensitive layer coating solution onto a conductive substrate and drying. The photosensitive layer coating solution includes, for example, a charge generator, a hole transport agent, an electron transport agent, a binder resin, an n-type pigment, filler particles, and an additive that is added as necessary. It is prepared by dissolving or dispersing in a solvent.

  The solvent contained in the photosensitive layer coating solution (hereinafter sometimes referred to as 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. 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, diethylene glycol dimethyl ether, or propylene glycol monomethyl ether), ketones (more specifically, acetone, methyl ethyl ketone, cyclohexanone, etc.), esters More specifically, ethyl acetate or methyl acetate, etc.), dimethylformamide, dimethyl formamide, or dimethyl sulfoxide and the like. These solvents are used alone or in combination of two or more. In order to improve the workability during the production of the photoreceptor, it is preferable to use a non-halogen solvent (a solvent other than the halogenated hydrocarbon) as the solvent.

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

  The coating liquid may contain, for example, a surfactant in order to improve the dispersibility of each component.

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

  The method for drying the coating solution is not particularly limited as long as the solvent in the coating solution can be evaporated. For example, the method of heat-processing (hot-air drying) is mentioned using a high-temperature dryer or a vacuum dryer. The heat treatment conditions are, for example, a temperature of 40 ° C. or higher and 150 ° C. or lower and a time of 3 minutes or longer and 120 minutes or shorter.

  In addition, the manufacturing method of a photoreceptor may further include one or both of a step of forming an intermediate layer and a step of forming a protective layer as necessary. A known method is appropriately selected in the step of forming the intermediate layer and the step of forming the protective layer.

  The photoreceptor according to the first embodiment has been described above. According to the photoconductor of the first embodiment, the filming resistance is excellent and the generation of a transfer memory can be suppressed.

<Second Embodiment: Image Forming Apparatus>
The second embodiment relates to an image forming apparatus. Hereinafter, an aspect of the image forming apparatus according to the second embodiment will be described with reference to FIG. FIG. 2 is a diagram illustrating an example of an image forming apparatus according to the second embodiment. The image forming apparatus 100 according to the second embodiment includes an image carrier 30, a charging unit 42, an exposure unit 44, a developing unit 46, and a transfer unit 48. The image carrier 30 is a photoconductor according to the first embodiment. The charging unit 42 charges the surface of the image carrier 30. The charging polarity of the charging unit 42 is positive. The exposure unit 44 exposes the charged surface of the image carrier 30 to form an electrostatic latent image on the surface of the image carrier 30. The developing unit 46 develops the electrostatic latent image as a toner image using a developer. The transfer unit 48 transfers the toner image from the image carrier 30 to the recording medium while the surface of the image carrier 30 and the recording medium P are in contact with each other. The outline of the image forming apparatus according to the second embodiment has been described above.

  The image forming apparatus 100 according to the second embodiment can suppress image defects caused by filming and generation of a transfer memory. The reason is presumed as follows. The image forming apparatus 100 according to the second embodiment includes the photoconductor according to the first embodiment as the image carrier 30. The photoconductor according to the first embodiment has excellent filming resistance and can suppress the generation of a transfer memory. Therefore, the image forming apparatus 100 according to the second embodiment can suppress image defects caused by the occurrence of filming and transfer memory. Hereinafter, suppression of generation of the transfer memory will be described in detail.

  First, for the sake of convenience, image defects caused by the transfer memory will be described. As described above, when a transfer memory is generated in the image forming process, when the circumference of the photoconductor in image formation is used as a reference (hereinafter sometimes referred to as a reference circumference), the next circumference on the surface of the image carrier 30 is obtained. In the region where the desired potential cannot be obtained in the charging step, the potential tends to be lower than the region where the desired potential can be obtained in the next charging step. Specifically, the potential of the non-exposure area in the previous round on the surface of the image carrier 30 tends to decrease during the next round of charging as compared to the exposure area in the previous round. For this reason, the non-exposure area in the previous round is more likely to attract the positively charged toner during development because the potential at the time of charging tends to be lower than the exposure area in the previous round. As a result, an image reflecting a non-image portion (non-exposed area) on the reference circumference is easily formed. An image defect in which an image reflecting the image portion of the reference circumference is formed is an image defect caused by the transfer memory (hereinafter sometimes referred to as an image ghost).

  With reference to FIG. 3, an image in which an image defect has occurred will be described. FIG. 3 is a diagram illustrating an image 60 in which an image ghost has occurred. The image 60 includes a region 62 and a region 64. The region 62 is a region corresponding to one rotation of the image carrier, and the region 64 is a region corresponding to one rotation of the image carrier. Region 62 includes an image 66. The image 66 is composed of a donut-shaped solid image. Region 64 includes image 68 and image 69. The image 68 is a donut-shaped halftone image. The image 69 is a donut-shaped white halftone image in the region 64. The image 69 has a higher image density than the image 68. The image 69 is an image defect (image ghost) that reflects the non-exposed area of the area 62 and becomes darker than the design image density. Note that the image in the region 64 is composed of the entire halftone image on the design image.

  The photoreceptor according to the first embodiment tends to suppress the occurrence of image defects due to the transfer memory as described above. Therefore, since the image forming apparatus 100 according to the second embodiment includes the photoconductor according to the first embodiment as the image carrier 30, it is considered that the occurrence of image defects due to the transfer memory can be suppressed.

  Hereinafter, each part will be described in detail. An image forming apparatus 100 according to the second embodiment will be described with reference to FIG. The image forming apparatus 100 is not particularly limited as long as it is an electrophotographic image forming apparatus. The image forming apparatus 100 may be, for example, a monochrome image forming apparatus or a color image forming apparatus. When the image forming apparatus 100 is a color image forming apparatus, the image forming apparatus 100 employs, for example, a tandem method. Hereinafter, the tandem image forming apparatus 100 will be described as an example.

  The image forming apparatus 100 employs a direct transfer method. Usually, in an image forming apparatus that employs a direct transfer system, the image carrier 30 is likely to be affected by a transfer bias, and therefore, a transfer memory is usually easily generated. In addition, in an image forming apparatus that employs a direct transfer method, the image carrier 30 may come into contact with a recording medium. Therefore, minute components are likely to adhere to the surface of the image carrier 30, resulting in filming. Image defects are likely to occur. However, the image forming apparatus 100 according to the second embodiment includes the photoconductor according to the first embodiment as the image carrier 30. The photoconductor according to the first embodiment has excellent filming resistance and can suppress the generation of a transfer memory. Therefore, when the image bearing member 30 includes the photoconductor according to the first embodiment, even when the image forming apparatus 100 adopts the direct transfer method, occurrence of image defects due to filming and transfer memory is suppressed. It is considered possible.

  The image forming apparatus 100 includes image forming units 40a, 40b, 40c, and 40d, a transfer belt 50, and a fixing unit 54. 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 an image carrier 30, a charging unit 42, an exposure unit 44, a developing unit 46, and a transfer unit 48. The image forming unit 40 can further include a cleaning unit 52. The cleaning unit 52 is a cleaning blade. An image carrier 30 is provided at the center position of the image forming unit 40. The image carrier 30 is provided to be rotatable in the arrow direction (counterclockwise). Around the image carrier 30, a charging unit 42, an exposure unit 44, a developing unit 46, a transfer unit 48, and a cleaning unit 52 are provided in order from the upstream side in the rotation direction of the image carrier 30 with respect to the charging unit 42. It is done. Note that the image forming unit 40 may further include a charge removal unit (not shown).

  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 100 is a monochrome image forming apparatus, the image forming apparatus 100 includes an image forming unit 40a, and the image forming units 40b to 40d are omitted.

  The charging unit 42 is a charging roller. The charging roller charges the surface of the image carrier 30 while being in contact with the surface of the image carrier 30. Usually, in an image forming apparatus provided with a charging roller, image defects due to filming and transfer memory are likely to occur. However, the photoconductor according to the first embodiment is provided in the image forming apparatus 100 as the image carrier 30. The photoconductor according to the first embodiment has excellent filming resistance and can suppress the generation of a transfer memory. Accordingly, even when the charging roller is provided in the image forming apparatus 100 as the charging unit 42, the occurrence of image defects due to the occurrence of filming and transfer memory is suppressed. Examples of other contact charging type charging units include a charging brush. The charging unit 42 may be a non-contact type. Examples of the non-contact type charging unit include a corotron charging unit and a scorotron charging unit.

  The voltage applied by the charging unit 42 is not particularly limited. The voltage applied by the charging unit 42 includes a DC voltage, an AC voltage, or a superimposed voltage (a voltage obtained by superimposing an AC voltage on a DC voltage), and more preferably a DC voltage. DC voltage has the following advantages over AC voltage or superimposed voltage. When the charging unit 42 applies only a DC voltage, the voltage value applied to the image carrier 30 is constant, so that the surface of the image carrier 30 is easily charged uniformly to a constant potential. Further, when the charging unit 42 applies only a DC voltage, the wear amount of the photosensitive layer tends to decrease. As a result, a suitable image can be formed.

  The exposure unit 44 exposes the surface of the charged image carrier 30. As a result, 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 the image forming apparatus 100.

  The developing unit 46 develops the electrostatic latent image as a toner image using a developer. The developer may be a one-component developer or a two-component developer. The developer may include a polymerized toner. Usually, when the developer contains polymerized toner, the polymerized toner remaining on the surface of the photoreceptor after image formation is difficult to be removed by a cleaning unit (for example, a cleaning blade). In such a case, a minute component adheres to the surface of the photoreceptor and filming is likely to occur. However, the image forming apparatus 100 according to the second embodiment includes the photoconductor according to the first embodiment as the image carrier 30. The photoconductor according to the first embodiment is excellent in filming resistance. For this reason, the image forming apparatus 100 according to the second embodiment can suppress image defects due to filming even when the developer includes polymerized toner.

  The transfer belt 50 conveys the recording medium P between the image carrier 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 to the recording medium P. When the toner image is transferred from the image carrier to the recording medium P, the image carrier is in contact with the recording medium P. An example of the transfer unit 48 is a transfer roller.

  The fixing unit 54 heats and / or pressurizes the unfixed toner image transferred to the recording medium P by the transfer unit 48. The fixing unit 54 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 second embodiment has been described above. The image forming apparatus according to the second embodiment can suppress the occurrence of image defects by including the photoconductor according to the first embodiment as an image carrier.

<Third embodiment: Process cartridge>
The third embodiment relates to a process cartridge. A process cartridge according to the third embodiment includes the photoconductor according to the first embodiment. Next, the process cartridge according to the third embodiment will be described with reference to FIG.

  The process cartridge includes a unitized image carrier. The process cartridge employs a configuration in which at least one selected from the group consisting of a charging unit 42, an exposure unit 44, a developing unit 46, a transfer unit 48, and a cleaning unit 52 is unitized in addition to the image carrier 30. The The process cartridge corresponds to each of the image forming units 40a to 40d, for example. The process cartridge may further include a static eliminator (not shown). The process cartridge is designed to be detachable from the image forming apparatus 100. Therefore, the process cartridge is easy to handle, and when the sensitivity characteristics and the like of the image carrier 30 are deteriorated, the process cartridge including the image carrier 30 can be easily and quickly replaced.

  The process cartridge according to the third embodiment has been described above. Since the process cartridge according to the third embodiment includes the photoconductor according to the first embodiment as an image carrier, it is possible to suppress the occurrence of image defects due to filming and transfer memory.

  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. Photosensitive Material>
The following electron transport agent, hole transport agent, charge generator, binder resin, n-type pigment, and filler particles were prepared as materials for forming a single-layer photosensitive layer of the single-layer photoreceptor.

[1-1. Electron transport agent]
The electron transport agents (ETM1-1) to (ETM5-1) described in the first embodiment were prepared.

[1-2. Hole transport agent]
The hole transport agents (HTM-1) to (HTM-6) described in the first embodiment were prepared.

[1-3. Charge generator]
[1-3-1. Y-type titanyl phthalocyanine crystal]
The charge generating agents (CGM-1) to (CGM-3) described in the first embodiment were prepared. The charge generating agent (CGM-1) was titanyl phthalocyanine (Y-type titanyl phthalocyanine crystal) represented by the chemical formula (CGM-A). The crystal structure of the charge generating agent (CGM-1) was Y-type.

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

  The Y-type titanyl phthalocyanine crystal has no peak in the range of 50 ° C. or higher and lower than 270 ° C. in the differential scanning calorimetry spectrum other than the peak accompanying vaporization of adsorbed water, and one peak in the range of 270 ° C. or higher and 400 ° C. or lower. Had. Note that the differential scanning calorimetry spectrum was measured using the measurement apparatus and measurement conditions described in the first embodiment.

  Y-type titanyl phthalocyanine crystals were prepared as follows.

(Synthesis process)
The flask was used as a reaction vessel. The reaction vessel was purged with argon. Into the reaction vessel, 25 g of 1,3-diiminoisoindoline, 22 g of titanium tetrabutoxide, and 300 g of diphenylmethane were charged. While stirring the mixture in these reaction vessels, the temperature in the reaction vessel was raised to 150 ° C.

  Next, the temperature inside the reaction vessel was raised to 215 ° C. while vapor generated from the reaction system was distilled out of the system. While maintaining the temperature in the reaction vessel at 215 ° C., the mixture was further reacted by stirring for 4 hours.

  After completion of the reaction, when the temperature in the reaction vessel was cooled to 150 ° C., the contents in the reaction vessel were taken out from the reaction vessel. The contents were filtered off with a glass filter to obtain a solid. The solid was washed sequentially with N, N-dimethylformamide and methanol. Then, it was vacuum dried to obtain 24 g of a purple solid.

(Pre-pigmentation process)
A purple solid (10 g) and N, N-dimethylformamide (100 mL) were charged into a reaction vessel to prepare a solution. While stirring the solution, the temperature in the reaction vessel was raised to 130 ° C. The solution was stirred for an additional 2 hours. Subsequently, heating of the solution was stopped when 2 hours had passed. After cooling the temperature in the reaction vessel to room temperature (23 ± 1 ° C.), stirring was also stopped. In this state, the contents in the reaction vessel were allowed to stand for 12 hours, and a stabilization process was performed. Then, the contents in the reaction vessel after the stabilization treatment were separated by a glass filter to obtain a solid. The solid was washed with methanol and dried in vacuo. As a result, 9.85 g of a crude crystal of titanyl phthalocyanine (CGM-A) was obtained.

(Pigmentation process)
100 mL of a mixed solvent of dichloromethane and trifluoroacetic acid (volume ratio dichloromethane: trifluoroacetic acid = 4: 1) was prepared. 5 g of crude crystals of titanyl phthalocyanine (CGM-A) were dissolved in 100 mL of a mixed solvent (volume ratio 4: 1) to prepare a mixed solution A.

  A mixed poor solvent of methanol and water (volume ratio methanol: water = 1: 1) was prepared. The mixed solution A was dropped into the mixed poor solvent to prepare a mixed solution B. Next, the mixed solution B was stirred at room temperature for 15 minutes and then allowed to stand for 30 minutes. As a result, titanyl phthalocyanine (CGM-A) was recrystallized.

  The mixed solution B was filtered off with a glass filter to obtain a solid. The solid was washed with water until the washing solution became neutral. The solid was then dispersed in 200 mL of chlorobenzene and stirred for 1 hour in the presence of water without drying. Subsequently, it filtered by the glass filter and obtained solid. The solid was vacuum dried at 50 ° C. for 5 hours. As a result, 4.2 g of Y-type titanyl phthalocyanine crystal (blue powder) was obtained.

[1-3-2. X-type metal-free phthalocyanine]
The charge generator (CGM-2) was a metal-free phthalocyanine (X-type metal-free phthalocyanine) represented by the chemical formula (CGM-B). The crystal structure of the charge generating agent (CGM-2) was X type.

[1-3-3. α-type titanyl phthalocyanine crystal]
The charge generating agent (CGM-3) was titanyl phthalocyanine (α-type titanyl phthalocyanine crystal) represented by the chemical formula (CGM-A). The crystal structure of the charge generating agent (CGM-3) was α-type.

  α-type titanyl phthalocyanine crystals were prepared as follows. The CuKα characteristic X-ray diffraction spectrum of the α-type titanyl phthalocyanine crystal was measured in the same manner as the Y-type titanyl phthalocyanine crystal. The α-type titanyl phthalocyanine crystal has Bragg angles 2θ ± 0.2 ° = 7.5 °, 10.2 °, 12.6 °, 13.2 °, 15.1 °, 16 in the CuKα characteristic X-ray diffraction spectrum chart. .3 °, 17.3 °, 18.3 °, 22.5 °, 24.2 °, 25.3 °, and 28.6 °, and the main peak was 28.6 °. It was.

  50 g (0.39 mol) of o-phthalonitrile and 750 mL of quinoline were placed in a 2 L flask, and 42.5 g (0.22 mol) of titanium tetrachloride was added while stirring under a nitrogen atmosphere. Then, the temperature in the flask was raised to 200 ° C., and the contents were reacted by heating and stirring at 200 ° C. for 5 hours. After completion of the reaction, the mixture was filtered with heating, and washed with 500 mL of hot DMF to obtain a wet cake. The obtained wet cake was added into 300 mL of DMF and stirred at 130 ° C. for 2 hours. Subsequently, hot filtration was performed at 130 ° C., followed by washing with 500 mL of DMF. After repeating this operation four times, the wet cake was washed with 750 mL of methanol.

  The wet cake that had been washed with methanol was dried under reduced pressure at 40 ° C. to obtain crude synthetic titanyl phthalocyanine (yield: 43 g). Subsequently, 400 g of concentrated sulfuric acid was cooled to 5 ° C. or lower in a methanol bath, and 30 g (0.052 mol) of crude synthetic titanyl phthalocyanine was added to the concentrated sulfuric acid while keeping the temperature at 5 ° C. or lower. After stirring this for 1 hour, the resulting reaction mixture was added dropwise to 10 L of water (5 ° C.), and this was stirred at room temperature for 3 hours, then allowed to stand, and then filtered to obtain a wet cake. .

  The obtained wet cake was added to 500 mL of water, stirred at room temperature for 1 hour, and then filtered. This operation was repeated twice. Further, the wet cake after washing with water was put into 5 L of water, stirred at room temperature for 1 hour, allowed to stand, and then filtered. This operation was repeated twice. Thereafter, the cake was washed with 2 L of ion-exchanged water, and the wet cake was collected when the pH was 6.2 or more and the conductivity was 20 μS or less. The wet cake was dried to obtain a low crystalline phthalocyanine (blue powder, yield: 25 g). This low crystalline phthalocyanine had peaks at Bragg angles 2θ ± 0.2 ° = 7.0 °, 15.6 °, 23.5 °, and 28.4 ° in the CuKα characteristic X-ray diffraction spectrum.

  24 g of low crystalline titanyl phthalocyanine, 400 mL of DMF, and an appropriate amount of glass beads (1 mmφ) were charged into a 900 mL mayonnaise bottle and dispersed in a bead mill for 24 hours. Next, the glass beads were separated and then filtered. The cake after filtration was washed with a mixed solution of 400 mL of DMF and 400 mL of methanol. The washed cake was dried under reduced pressure at 50 ° C. for 48 hours to obtain a solid. The obtained solid was pulverized to obtain α-type titanyl phthalocyanine crystals (yield 21 g).

[1-4. Binder resin]
Polycarbonate resins (PC-1) to (PC-5) (viscosity average molecular weights: 50000, 48500, 49800, 50000, and 50000, respectively) described in the first embodiment as the binder resin and polyarylate resin (PAR-1) ( Viscosity average molecular weight 50000) was prepared.

[1-5. Filler particles]
Table 1 shows the filler particles used in Examples and Comparative Examples. Table 1 shows the type, material, volume median diameter, trade name, and manufacturer of the filler particles. The resin of filler particles F7, F9, and F10 contained a fluorine atom. Note that “AEROSIL” and “Trepearl” in the column “Product Name” in Table 1 are registered trademarks. In Table 1, the volume median diameter D ₅₀ of the filler particles was measured using the precision particle size distribution measuring apparatus described in the first embodiment.

[1-6. n-type pigment]
The n-type pigments (N1) to (N9) described in the first embodiment were prepared.

<2. Manufacture of photoconductor>
Photoconductors (A-1) to (A-37) and photoconductors (B-1) to (B-4) were produced using materials for forming the photosensitive layer.

[2-1. Production of photoconductor (A-1)]
Charge generator (CGM-1) 3 parts by mass, hole transport agent (HTM-1) 60 parts by mass, electron transport agent (ETM1-1) 35 parts by mass, filler particles (F7) 5 parts by mass, n-type pigment ( N1) 2 parts by mass, 100 parts by mass of a polycarbonate resin (PC-1) as a binder resin, and 800 parts by mass of tetrahydrofuran as a solvent were put in a container. The material in the container and the solvent were mixed for 2 minutes using a rod-like acoustic oscillator, and the material was dispersed in the solvent. Further, using a ball mill, the material in the container and the solvent were mixed for 50 hours to disperse the material in the solvent. This obtained the coating liquid for photosensitive layers. The photosensitive layer coating solution was coated on an aluminum drum-shaped support as a conductive substrate using a dip coating method. The applied photosensitive layer coating solution was dried with hot air at 100 ° C. for 40 minutes. Thereby, a single-layer type photosensitive layer (film thickness: 25 μm) was formed on the conductive substrate. As a result, a photoreceptor (A-1) was obtained. In the photoreceptor (A-1), the conductive substrate had an oxide coating, and the photosensitive layer was indirectly disposed on the conductive substrate via the oxide coating.

[2-2. Production of photoconductors (A-2) to (A-38) and photoconductors (B-1) to (B-6)]
The photoconductors (A-2) to (A-38) and the photoconductors (B-1) to (B-6) were produced in the same manner as in the production of the photoconductor (A-1) except that the following points were changed. ) Were produced respectively. The charge generating agent (CGM-1) used for the production of the photoreceptor (A-1) was changed to the types of charge generating agents shown in Tables 2 to 4. The electron transport agent (ETM1-1) used for the production of the photoreceptor (A-1) was changed to the types of electron transport agents shown in Tables 2 to 4. The hole transport agent (HTM-1) used for the production of the photoreceptor (A-1) was changed to the types of hole transport agents shown in Tables 2 to 4. The filler particles F7 used in the production of the photoreceptor (A-1) and the content of 5 parts by mass were changed to the types and contents of filler particles shown in Tables 2 to 4, respectively. The n-type pigment (N1) used in the production of the photoreceptor (A-1) and its content of 2 parts by mass were changed to the types and contents of n-type pigments shown in Tables 2 to 4, respectively. The polycarbonate resin (PC-1) as the binder resin used for the production of the photoreceptor (A-1) was changed to a binder resin of the type shown in Tables 2 to 4.

  Tables 2 to 4 show the structures of the photoreceptors (A-1) to (A-38) and the photoreceptors (B-1) to (B-6). In Tables 2 to 4, CGM, HTM, and ETM represent a charge generator, a hole transport agent, and an electron transport agent, respectively. In Tables 2 to 4, CGM-1, CGM-2, and CGM-3 in the CGM column respectively represent Y-type titanyl phthalocyanine crystal (charge generator (CGM-1)) and X-type metal-free phthalocyanine (charge generator ( CGM-2)) and α-type titanyl phthalocyanine crystal (charge generation agent (CGM-3)). HTM-1 to HTM-6 in the HTM column indicate hole transport agents (HTM-1) to (HTM-7), respectively. ETM1-1, ETM2-1, ETM3-1, ETM4-1, and ETM5-1 in the ETM column are respectively electron transport agents (ETM1-1), (ETM2-1), (ETM3-1), (ETM4- 1) and (ETM5-1) are shown. In Tables 2 to 4, F1, F3 to F4, F6 to F7, and F9 to F12 in the type column of filler particles indicate filler particles F1, F3 to F4, F6 to F7, and F9 to F12, respectively. In Tables 2 to 4, N1 to N9 in the type column of n-type pigment represent n-type pigments (N1) to (N9), respectively. In Tables 2 to 4, PC-1 to PC-5 and PAR-1 in the type of binder column indicate polycarbonate resins (PC-1) to (PC-5) and polyarylate resin (PAR-1), respectively.

<3. Evaluation of photoconductor>
[3-1. Evaluation of image defect (image ghost)]
Image defect (image ghost) was evaluated for each of the photoreceptors (A-1) to (A-38) and the photoreceptors (B-1) to (B-6). Evaluation of image defects was performed in an environment of a temperature of 10 ° C. and a relative humidity of 20% RH.

  The photoconductor was mounted on an evaluation machine. As the evaluation machine, an image forming apparatus (“FS-C5250DN” modified machine manufactured by Kyocera Document Solutions Co., Ltd.) was used. This evaluation machine adopted a contact charging method and a direct transfer method. This evaluator was provided with a charging roller as a contact charging type charging unit. This evaluator did not include a cleaning blade as a cleaning unit. As a recording medium, “Kyocera Document Solutions Brand Paper VM-A4” (A4 size) sold by Kyocera Document Solutions Inc. was used. Polymerized toner (“Prototype” one-component developer manufactured by Kyocera Document Solutions Co., Ltd.) was filled in the developing section of the evaluation machine.

  First, 1000 print patterns (image density 4%) were printed on a recording medium (A4 size paper) at intervals of 15 seconds, and a print test was performed. Then, the image for evaluation was created by the following operation.

  The evaluation image will be described with reference to FIG. FIG. 4 is a diagram showing the evaluation image 70. The evaluation image 70 includes a region 72 and a region 74. The region 72 is a region corresponding to one rotation of the image carrier. Region 72 includes an image 76. The image 76 is composed of a donut-shaped solid image (image density 100%). This solid image is composed of a set of two concentric circles. The region 74 is a region corresponding to one rotation of the image carrier. Region 74 includes an image 78. The image 78 is composed of an entire halftone image (image density 40%). First, an image 76 of the region 72 was formed, and then an image 78 of the region 74 was formed. The image 76 is an image corresponding to one rotation of the photosensitive member, and the image 78 is an image corresponding to one rotation of the next turn on the basis of the rotation in which the image 76 is formed.

Next, an image obtained after the printing test was used as an evaluation image. The image for evaluation was visually observed, and the presence or absence of an image corresponding to the image 76 in the region 74 was confirmed. Here, visual observation is observation with the naked eye (visual observation) or observation through a loupe (magnification 10 times, manufactured by TRUSCO, TL-SL10K) (loupe observation). The presence or absence of image defects (image ghosts) due to the transfer memory was confirmed. The presence or absence of image ghost was evaluated based on the following criteria. The evaluation results are shown in Tables 5-6. In addition, evaluation AC was set as the pass.
(Image ghost evaluation criteria)
Evaluation A: An image ghost corresponding to the image 76 was not observed.
Evaluation B: A slight image ghost corresponding to the image 76 was observed.
Evaluation C: Although an image ghost corresponding to the image 76 was observed, it was a level with no practical problem.
Evaluation D: An image ghost corresponding to the image 76 was clearly observed, which was a practically problematic level. The contrast between the image ghost observed in the image evaluation sample and the non-image portion where no image ghost was observed was low.

[3-2. Evaluation of filming resistance of single layer type photoconductor]
Filming resistance was evaluated for each of the photoreceptors (A-1) to (A-38) and the photoreceptors (B-1) to (B-6). The filming resistance was evaluated in an environment of a temperature of 10 ° C. and a relative humidity of 15% RH. The evaluation machine used was the same as the image forming apparatus used in the evaluation of image defects.

  First, a printing test was performed. Specifically, 5000 print patterns (image density of 1%) were printed on a recording medium (A4 size paper) at intervals of 15 seconds. After the printing test, an evaluation image was created. Specifically, one halftone image (image density 50%) was printed as an evaluation image. The image for evaluation was visually observed to confirm the presence or absence of image defects (streaks, dash marks) caused by filming. A streak is a line parallel to the printing direction. A dash mark is a linear streak parallel to the printing direction. The presence or absence of image defects was evaluated based on the following criteria. The evaluation results are shown in Tables 4-5. In addition, evaluation AC was set as the pass.

(Filming resistance evaluation criteria)
Evaluation A: Muscle and dash marks were not observed.
Evaluation B: Slight streaks and dash marks were observed.
Evaluation C: Although streaks and dash marks were partially observed, it was a level with no practical problem.
Evaluation D: Streaks and dash marks were clearly observed as a whole, and there were practically problematic levels.

[Comprehensive evaluation]
Based on the evaluation results of the transfer memory and the filming resistance, a comprehensive evaluation of the photoconductor was performed based on the following criteria.
Evaluation A: The evaluation result of the transfer memory and the evaluation result of the filming resistance were both evaluation A.
Evaluation B: The evaluation result of the transfer memory and the evaluation result of the filming resistance were not evaluation C or D, and at least one of these evaluation results was evaluation B.
Evaluation C: At least one of the evaluation results of the transfer memory and the filming resistance was evaluation D.

  As shown in Tables 2 and 3, in the photoreceptors (A-1) to (A-38), the photosensitive layer has a charge generator, a hole transport agent, an electron transport agent, an n-type pigment, and a filler. Particles and binder resin were included. Specifically, the filler particles were any one of F1, F3 to F4, F6 to F7, and F9 to F10. These filler particles were silica particles or resin particles. The content of the n-type pigment was 0.03 to 3 parts by mass with respect to 1 part by mass of the phthalocyanine pigment.

  As shown in Table 5, in the photoreceptors (A-1) to (A-38), the overall evaluation result of the transfer memory and the filming resistance was A, B, or C.

  As shown in Table 4, in the photoreceptor (B-1), the photosensitive layer did not contain an n-type pigment. In the photoreceptor (B-2), the photosensitive layer did not contain filler particles. In the photoreceptors (B-3) to (B-4), the content of the n-type pigment in the photosensitive layer was less than 0.03 parts by mass or more than 3 parts by mass with respect to 1 part by mass of the phthalocyanine pigment. In the photoreceptors (B-5) to (B-6), the photosensitive layer contained filler particles F11 or F12. The filler particles F11 and F12 were neither silica particles nor resin particles.

  As shown in Table 6, in the photoreceptors (B-1) to (B-6), the overall evaluation results of the transfer memory and the filming resistance were all D.

  The photoconductors (A-1) to (A-38) suppress the generation of a transfer memory and are excellent in filming resistance compared to the photoconductors (B-1) to (B-6).

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

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 3 Photosensitive layer 3a Single layer type photosensitive layer

Claims (21)

A single-layer electrophotographic photoreceptor comprising a conductive substrate and a photosensitive layer,
The photosensitive layer is a single-layer type photosensitive layer,
The photosensitive layer includes a charge generator, a hole transport agent, an electron transport agent, a binder resin, an n-type pigment, and filler particles.
The charge generating agent includes a phthalocyanine pigment,
The content of the n-type pigment is 0.03 parts by mass or more and 3 parts by mass or less with respect to 1 part by mass of the phthalocyanine pigment.
The filler particle is a single layer type electrophotographic photosensitive member, which is a silica particle or a resin particle.   The single-layer electrophotographic photosensitive member according to claim 1, wherein the n-type pigment is a perylene pigment or an azo pigment.   The single-layer electrophotographic photosensitive member according to claim 2, wherein the n-type pigment includes two or more selected from the group consisting of the perylene pigment and the azo pigment.   The single layer type electrophotographic photosensitive member according to any one of claims 1 to 3, wherein a volume median diameter of the filler particles is 5 nm or more and 10 µm or less.   5. The single-layer electrophotographic photoreceptor according to claim 1, wherein the content of the filler particles is 0.5 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin.   The single-layer electrophotographic photosensitive member according to any one of claims 1 to 5, wherein the resin particles contain fluorine atoms. The single-layer electrophotographic photosensitive member according to claim 1, wherein the binder resin has a repeating unit represented by the general formula (3) or the general formula (4).

In the general formula (3),
R ¹¹ and R ¹² each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, or a phenyl group which may have a substituent,
R ¹¹ and R ¹² may represent a cycloalkylidene group formed by bonding to each other;
R ¹¹ and R ¹² may be the same or different from each other,
R ¹³ and R ¹⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms which may have a halogen atom,
R ¹³ and R ¹⁴ may be the same as or different from each other;
In the general formula (4),
R ¹⁵ and R ¹⁶ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, or a phenyl group which may have a substituent,
R ¹⁵ and R ¹⁶ may represent a cycloalkylidene group formed by bonding to each other;
R ¹⁵ and R ¹⁶ may be the same as or different from each other;
R ¹⁷ and R ¹⁸ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms which may have a halogen atom,
R ¹⁷ and R ¹⁸ may be the same or different from each other. In the general formula (3),
R ¹¹ and R ¹² represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or a cycloalkylidene group having 5 to 7 carbon atoms formed by bonding to each other;
R ¹³ and R ¹⁴ represent a hydrogen group or a methyl group which may have a halogen atom,
R ¹³ and R ¹⁴ are the same as each other;
In the general formula (4),
R ¹⁵ and R ¹⁶ represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,
R ¹⁵ and R ¹⁶ are different from each other,
R ¹⁷ and R ¹⁸ represent an alkyl group having 1 to 3 carbon atoms,
R ¹⁷ and R ¹⁸ are the same as each other;
R ¹⁹ and R ²⁰ represent a hydrogen atom,
The single-layer electrophotographic photosensitive member according to claim 7, wherein R ¹⁹ and R ²⁰ are the same as each other. The binder resin has a repeating unit represented by a chemical formula (PC-1), a chemical formula (PC-2), a chemical formula (PC-3), a chemical formula (PC-4), or a chemical formula (PAR-1). The single-layer electrophotographic photosensitive member according to 7 or 8.

The phthalocyanine pigment is a Y-type titanyl phthalocyanine crystal,
10. The single layer according to claim 1, wherein the Y-type titanyl phthalocyanine crystal has a main peak at a Bragg angle 2θ ± 0.2 ° = 27.2 ° in a CuKα characteristic X-ray diffraction spectrum. Type electrophotographic photoreceptor. The phthalocyanine pigment is a Y-type titanyl phthalocyanine crystal,
The Y-type titanyl phthalocyanine crystal has a main peak at a Bragg angle 2θ ± 0.2 ° = 27.2 ° in a CuKα characteristic X-ray diffraction spectrum, and accompanies vaporization of adsorbed water in a differential scanning calorimetry spectrum. The peak according to any one of claims 1 to 9, which has no peak in a range of 50 ° C or higher and lower than 270 ° C except for a peak and has one peak in a range of 270 ° C or higher and 400 ° C or lower. Single layer type electrophotographic photoreceptor. The electron transport agent includes a compound represented by General Formula (ETM1), General Formula (ETM2), General Formula (ETM3), General Formula (ETM4), or General Formula (ETM5). The single-layer electrophotographic photosensitive member according to any one of the above.

In the general formula (ETM1),
R ⁶¹ , R ⁶² , R ⁶³ , and R ⁶⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms that may have a substituent, or a carbon atom that may have a substituent. Represents an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms which may have a substituent, or an aralkyl group having 7 to 20 carbon atoms which may have a substituent; R ⁶¹ , R ⁶² , R ⁶³ , and R ⁶⁴ may be the same as or different from each other.
In the general formula (ETM2),
R ³³ , R ³⁴ , R ³⁵ , and R ³⁶ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms that may have a substituent, or a carbon atom that may have a substituent. An alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms which may have a substituent, an aryl group having 6 to 14 carbon atoms which may have a substituent, and a substituent; An aralkyl group having 7 to 20 carbon atoms that may have, or a heterocyclic group having 3 to 14 carbon atoms that may have a substituent,
In the general formula (ETM3),
R ⁶⁵ represents an alkyl group having 1 to 6 carbon atoms which may have a substituent, or an aryl group having 6 to 14 carbon atoms which may have a substituent,
R ⁶⁶ may have an alkyl group having 1 to 6 carbon atoms which may have a substituent, an aryl group having 6 to 14 carbon atoms which may have a substituent, or a substituent. An alkoxy group having 1 to 6 carbon atoms, an aryloxy group having 6 to 14 carbon atoms that may have a substituent and an aralkyl group substituent having 7 to 20 carbon atoms, or Represents an aralkyloxy group having 7 to 20 carbon atoms which may have a substituent,
R ⁶⁶ represents an alkyl group having 1 to 6 carbon atoms which may have a substituent,
s represents an integer of 0 or more and 4 or less,
R ⁶⁵ , R ⁶⁶ , and R ⁶⁷ may be the same as or different from each other.
In the general formula (ETM4),
R ³⁹ and R ⁴⁰ each independently represents an aryl group having 6 to 14 carbon atoms, which may have one or more alkyl groups having 1 to 6 carbon atoms,
In the general formula (ETM5),
R ⁴¹ , R ⁴² , and R ⁴³ each independently represents an aryl group having 6 to 14 carbon atoms or an alkyl group having 1 to 6 carbon atoms, which may have a halogen atom.   The single-layer electrophotographic photosensitive member according to claim 12, wherein the electron transport agent includes the compound represented by the general formula (ETM1), the general formula (ETM4), or the general formula (ETM5). The hole transport agent is represented by the general formula (HTM1), general formula (HTM2), general formula (HTM3), general formula (HTM4), general formula (HTM5), general formula (HTM6), or general formula (HTM7). The single-layer electrophotographic photosensitive member according to any one of claims 1 to 13, comprising the compound represented.

In the general formula (HTM1),
Q ⁸ , Q ¹⁰ , Q ¹¹ , Q ¹² , Q ¹³ , and Q ¹⁴ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or Represents a phenyl group,
Q ⁹ and Q ¹⁵ each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group,
b represents an integer of 0 to 5, and when b represents an integer of 2 to 5, a plurality of Q ⁹ bonded to the same phenyl group may be the same or different from each other;
c represents an integer of 0 or more and 4 or less, and when c represents an integer of 2 or more and 4 or less, a plurality of Q ¹⁵ bonded to the same phenyl group may be the same or different from each other;
k represents 0 or 1.

In the general formula (HTM2),
Q ¹ represents a phenyl group which may have a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms. ,
Two Q ¹ may be the same or different from each other,
Q ² represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group,
Q ³ , Q ⁴ , Q ⁵ , Q ⁶ , and Q ⁷ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. And two adjacent ones of Q ³ , Q ⁴ , Q ⁵ , Q ⁶ , and Q ⁷ may be bonded to each other to form a ring,
a represents an integer of 0 to 5, and when a represents an integer of 2 to 5, a plurality of Q ² bonded to the same phenyl group may be the same as or different from each other. t and u each independently represents an integer of 0 or more and 2 or less.

In the general formula (HTM3),
Q ¹⁶ , Q ¹⁷ , Q ¹⁸ , and Q ¹⁹ each independently represent an alkyl group having 1 to 4 carbon atoms.

In the general formula (HTM4),
Q ²⁰ , Q ²¹ , Q ²² , and Q ²³ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In the general formula (HTM5),
R ^d , R ^e , and R ^f each independently represents an alkyl group having 1 to 6 carbon atoms,
o, p, and r each independently represent an integer of 0 to 5,
when o represents an integer of 2 or more and 4 or less, a plurality of R ^e bonded to the same phenyl group may be the same or different from each other;
when p represents an integer of 2 or more and 4 or less, a plurality of R ^f bonded to the same phenyl group may be the same or different from each other;
When r represents an integer of 2 or more and 4 or less, a plurality of R ^d bonded to the same phenyl group may be the same or different from each other.

In the general formula (HTM6),
R ^a , R ^b , and R ^c each independently represents an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an alkoxy group having 1 to 6 carbon atoms,
q represents an integer of 0 or more and 4 or less, and when q represents an integer of 2 or more and 4 or less, a plurality of R ^c bonded to the same phenyl group may be the same or different from each other;
m and n each independently represent an integer of 0 to 5, and when m represents an integer of 2 to 5, a plurality of R ^b bonded to the same phenyl group may be the same or different from each other. In the case where n represents an integer of 2 or more and 5 or less, a plurality of R ^a bonded to the same phenyl group may be the same or different from each other.

In the general formula (HTM7),
Q ³¹ , Q ³³ , and Q ³⁵ each independently represent an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group,
d, e, and f each independently represent an integer of 0 to 5,
Q ³² , Q ³⁴ , and Q ³⁶ 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 an alkyl having 1 to 6 carbon atoms Represents a phenyl group optionally substituted by a group,
g, h, and i each independently represents 0 or 1;   The single-layer electrophotographic photosensitive member according to claim 14, wherein the hole transport agent includes the compound represented by the general formula (HTM1), the general formula (HTM2), or the general formula (HTM3). .   The single layer according to any one of claims 1 to 15, wherein the photosensitive layer is disposed directly on the conductive substrate or indirectly through an undercoat layer or an oxide film. Type electrophotographic photoreceptor. 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 that develops the electrostatic latent image as a toner image using a developer;
An image forming apparatus comprising: a transfer unit that transfers the toner image from the image carrier to a recording medium;
The image carrier is the electrophotographic photosensitive member according to any one of claims 1 to 16,
The charging part has a positive polarity, and the transfer part transfers the toner image from the image carrier to the recording medium while the surface of the image carrier and the recording medium are in contact with each other. Forming equipment.   The image forming apparatus according to claim 17, wherein the charging unit charges the surface of the image carrier while being in contact with the surface of the image carrier.   The image forming apparatus according to claim 17, wherein the developer includes a polymerized toner. A cleaning unit;
The image forming apparatus according to claim 17, wherein the cleaning unit is a cleaning blade.   A process cartridge comprising the electrophotographic photosensitive member according to claim 1.

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