JP6617663B2 - Electrophotographic photosensitive member, image forming apparatus, and process cartridge - Google Patents

Description

  The present invention relates to an electrophotographic photoreceptor, 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 electrophotographic photosensitive member described in Patent Document 1 contains, for example, a compound represented by the following chemical formula (HTM-D).

JP 2013-50506 A

  However, the 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 an electrophotographic photosensitive member that has excellent filming resistance and suppresses 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 electrophotographic photosensitive member of the present invention includes a conductive substrate and a photosensitive layer. The photosensitive layer includes a charge generating agent, an enamine derivative, an electron transporting agent or an electron acceptor compound, a binder resin, and filler particles. The enamine derivative is represented by the general formula (1). The filler particles are silica particles or resin particles.

In the general formula (1), R ¹ , R ² , R ³ , R ⁴ , and R ⁵ are each independently an alkyl group having 1 to 6 carbon atoms which may have a substituent, and a substituent. An alkoxy group having 1 to 6 carbon atoms which may have, an aryl group having 6 to 14 carbon atoms which may have one or more substituents, and a carbon atom which may have substituents It represents an aryloxy group having 6 to 14 carbon atoms, an aralkyl group having 7 to 20 carbon atoms which may have a substituent, a halogen atom, or a hydrogen atom. n represents an integer of 0 or more and 4 or less.

  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 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. (A), (b) and (c) is a schematic sectional drawing which shows another example of the electrophotographic photoreceptor which concerns on 1st embodiment of this invention, respectively. 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 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 alkoxy group having 1 to 3 carbon atoms, an aryl group having 6 to 14 carbon atoms, and 7 to 20 carbon atoms An aralkyl group having 7 to 10 carbon atoms, an aralkyloxy group having 7 to 20 carbon atoms, an aralkyloxy group having 7 to 10 carbon atoms, and an aryloxy group having 6 to 14 carbon atoms A heterocyclic group having 3 to 14 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkylidene group having 5 to 7 carbon atoms, and amino Group, if not specified at all, respectively following meanings.

  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.

  The alkoxy group having 1 to 3 carbon atoms is linear or branched and unsubstituted. Examples of the alkoxy group having 1 to 3 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, and an isopropoxy group. The alkoxy 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.

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

  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.

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

  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. Specific examples of the heterocyclic group include thiophenyl group, furanyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, isothiazolyl group, isoxazolyl group, oxazolyl group, isoxazolyl group, thiazolyl group, isothiazolyl group, furazanyl group, pyranyl group, pyridyl group. , Pyridazinyl group, pyrimidinyl group, pyrazinyl group, indolyl group, 1H-indazolyl group, isoindolyl group, chromenyl group, quinolinyl group, isoquinolinyl group, purinyl group, pteridinyl group, triazolyl group, tetrazolyl group, 4H-quinolidinyl group, naphthyridinyl group, A benzofuranyl group, a 1,3-benzodioxolyl group, a benzoxazolyl group, a benzothiazolyl group, or a benzimidazolyl group can be mentioned. 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 cycloalkyl group having 3 to 10 carbon atoms is unsubstituted. Examples of the cycloalkyl group having 3 to 10 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, and a cyclodecyl group. The cycloalkyl group having 3 to 10 carbon atoms may have a substituent. 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, an aryl group having 6 to 14 carbon atoms, or A cyano group is mentioned.

  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>
An electrophotographic photoreceptor (hereinafter sometimes referred to as a photoreceptor) according to the first embodiment of the present invention includes a conductive substrate and a photosensitive layer. Examples of the photoreceptor include a single-layer electrophotographic photoreceptor (hereinafter sometimes referred to as a single-layer photoreceptor) or a multilayer electrophotographic photoreceptor (hereinafter referred to as a multilayer photoreceptor). ).

[1. Single-layer type photoreceptor]
Hereinafter, the structure of the single-layer type 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.

  In FIG. 1, the photoreceptor 1 is a single-layer photoreceptor. As shown in FIG. 1A, the single-layer type photoreceptor includes, for example, a conductive substrate 2 and a photosensitive layer 3. The single layer type photoreceptor 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 single-layer type photoreceptor 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.

[2. Multilayer photoreceptor]
In the multilayer photoreceptor, the photosensitive layer includes a charge generation layer and a charge transport layer. Hereinafter, the structure of the multilayer photoreceptor will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view showing another example of the photoreceptor 1 according to the second embodiment.

  In FIG. 2, the photoreceptor 1 is a stacked photoreceptor. As shown in FIG. 2A, the laminated photoreceptor includes, for example, a conductive substrate 2 and a photosensitive layer 3. The photosensitive layer 3 includes a charge generation layer 3b and a charge transport layer 3c. In order to improve the abrasion resistance of the multilayer photoreceptor, as shown in FIG. 2A, a charge generation layer 3b is provided on the conductive substrate 2, and a charge transport layer 3c is provided on the charge generation layer 3b. It is preferable to be provided. As shown in FIG. 2B, in the multilayer photoreceptor, the charge transport layer 3c may be provided on the conductive substrate 2, and the charge generation layer 3b may be provided on the charge transport layer 3c.

  As shown in FIG. 2 (c), the multilayer photoreceptor may include a conductive substrate 2, a photosensitive layer 3, and an intermediate layer (undercoat layer) 4. The intermediate layer 4 is provided between the conductive substrate 2 and the photosensitive layer 3. Further, a protective layer 5 (see FIG. 1C) may be provided on the photosensitive layer 3.

  The thicknesses of the charge generation layer 3b and the charge transport layer 3c are not particularly limited as long as the functions as the respective layers can be sufficiently expressed. The thickness of the charge generation layer 3b is preferably 0.01 μm or more and 5 μm or less, and more preferably 0.1 μm or more and 3 μm or less. The thickness of the charge transport layer 3c is preferably 2 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.

  The photoreceptor according to the first embodiment includes a photosensitive layer. The photosensitive layer includes a charge generating agent, an enamine derivative, an electron transporting agent or an electron acceptor compound, a binder resin, and filler particles. In the multilayer photoconductor, the charge generation layer includes, for example, a charge generation agent and a binder resin for charge generation agent (hereinafter sometimes referred to as a base resin). The charge transport layer includes, for example, an enamine derivative, an electron transport agent or an electron acceptor compound, a binder resin, and filler particles. In the single layer type photoreceptor, the single layer type photosensitive layer includes, for example, a charge generator, an enamine derivative, an electron transport agent or an electron acceptor compound, a binder resin, and filler particles. The charge generation layer, charge transport layer, and single-layer type photosensitive layer may further contain an additive.

  The photoconductor according to the first embodiment suppresses the generation of a transfer memory. The reason is presumed as follows. The photoconductor according to the first embodiment includes an enamine derivative. The enamine derivative is represented by the general formula (1) (hereinafter, the enamine derivative represented by the general formula (1) may be referred to as an enamine derivative (1)). The enamine derivative (1) has planarity and a relatively large π-conjugated system. For this reason, the photosensitive layer has an excellent hole transport ability, and charges as carriers tend not to remain in the photosensitive layer. Therefore, 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, an electron acceptor compound, a hole transport agent, a charge generating agent, a binder resin, a base resin, 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.

[3. 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.

[4. Electron transfer agent, electron acceptor compound]
In a single layer type photoreceptor, the single layer type photosensitive layer contains an electron transport agent. In the multilayer photoreceptor, the charge transport layer includes an electron acceptor compound.

  Examples of the electron transfer agent and the electron acceptor compound include quinone compounds, diimide compounds, hydrazone compounds, malononitrile compounds, thiopyran compounds, trinitrothioxanthone compounds, 3,4,5,7-tetranitro-9-. Fluorenone compounds, dinitroanthracene compounds, dinitroacridine compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroacridine, succinic anhydride, maleic anhydride, or dibromomaleic anhydride . Examples of the quinone compound 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 transfer agents and electron acceptor compounds, compounds represented by general formula (ETM1), general formula (ETM2), general formula (ETM3), general formula (ETM4), or general formula (ETM5) (hereinafter, It is preferable that each compound (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 the general formula (ETM1), R ⁶¹ , R ⁶² , R ⁶³ , and R ⁶⁴ each independently preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. More preferably, it represents 1 or more and 5 or less alkyl group, and further preferably represents a hydrogen atom or a 2-methyl-2-butyl group. Examples of the compound represented by the general formula (ETM1) include a compound represented by the chemical formula (ETM1-1) (hereinafter sometimes referred to as the compound (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 a t-butyl group. Examples of the compound represented by the general formula (ETM2) include a compound represented by the chemical formula (ETM2-1) (hereinafter sometimes referred to as the compound (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 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 which may have a substituent, or an aralkyloxy having 7 to 20 carbon atoms which may have a substituent Represents a group. 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 compound represented by the general formula (ETM3) include a compound represented by the chemical formula (ETM3-1) (hereinafter sometimes referred to as the compound (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. This represents an alkoxy group having 1 to 6 carbon atoms which may have, an aryl group having 6 to 14 carbon atoms which may have a substituent, and an amino group which may have a substituent. R ³⁹ and R ⁴⁰ may be the same as or different from each other. In general formula (ETM4), R ³⁹ and R ⁴⁰ preferably represent an aryl group having 6 to 14 carbon atoms, which may have one or more alkyl groups having 1 to 6 carbon atoms, More preferably, it represents a phenyl group having a plurality of alkyl groups having 1 to 3 carbon atoms, and more preferably an ethylmethylphenyl group. Examples of the compound represented by the general formula (ETM4) include a compound represented by the chemical formula (ETM4-1) (hereinafter sometimes referred to as the compound (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 compound represented by the general formula (ETM5) include a compound represented by the chemical formula (ETM5-1) (hereinafter sometimes referred to as the compound (ETM5-1)).

  Of these electron transfer agents and electron acceptor compounds, from the viewpoint of further improving the filming resistance of the photoreceptor, the compound (ETM1), the compound (ETM2), the compound (ETM3), or the compound (ETM4) is more preferable. Compound (ETM1) is more preferable. Among these electron transfer agents and electron acceptor compounds, from the viewpoint of further improving the filming resistance of the photoreceptor and further suppressing the generation of transfer memory, the compound (ETM1), the compound (ETM2), and the compound (ETM3) Or a compound (ETM4) is more preferable, and a compound (ETM1) is still more preferable.

[5. Hole transport agent]
The photosensitive layer contains an enamine derivative (1) as a hole transport agent. The enamine derivative (1) is represented by the general formula (1).

In general formula (1), R ¹ , R ² , R ³ , R ⁴ , and R ⁵ are each independently an alkyl group having 1 to 6 carbon atoms that may have a substituent, or a substituent. An alkoxy group having 1 to 6 carbon atoms which may have, an aryl group having 6 to 14 carbon atoms which may have one or more substituents, and a carbon atom which may have substituents It represents an aryloxy group having 6 to 14 carbon atoms, an aralkyl group having 7 to 20 carbon atoms which may have a substituent, a halogen atom, or a hydrogen atom. n represents an integer of 0 or more and 4 or less.

In general formula (1), the alkyl group having 1 to 6 carbon atoms represented by R ^{1 to} R ⁵ is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. The alkyl group having 1 to 6 carbon atoms represented by R ^{1 to} R ⁵ may have a substituent. Examples of such a substituent include a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or a heterocyclic group having 3 to 14 carbon atoms. It is done.

In general formula (1), the alkoxy group having 1 to 6 carbon atoms represented by R ^{1 to} R ⁵ may have a substituent. Examples of such a substituent include a halogen atom, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or a carbon atom. A heterocyclic group having a number of 3 or more and 14 or less is exemplified.

In general formula (1), the aryl group having 6 to 14 carbon atoms represented by R ^{1 to} R ⁵ is preferably a phenyl group. The aryl group having 6 to 14 carbon atoms represented by R ^{1 to} R ⁵ may have one or more substituents. Examples of such a substituent include an alkyl group having 1 to 3 carbon atoms, a halogen atom, and an alkoxy group having 1 to 3 carbon atoms, such as a methyl group, an ethyl group, a fluorine atom, and a chlorine atom. , An ethoxy group, or a methoxy group is preferable. Examples of the aryl group having 6 or more and 14 or less carbon atoms having one or more substituents include, for example, methylphenyl group, ethylmethylphenyl group, ethoxyphenyl group, methoxyphenyl group, dimethoxyphenyl group, chlorophenyl group, or fluorophenyl Groups. When the aryl group having 6 to 14 carbon atoms is a phenyl group, examples of the substitution position of the substituent include an ortho position (o position), a meta position (m position), and a para position (p position). The position or para position is preferred.

In general formula (1), the aryloxy group having 6 to 14 carbon atoms represented by R ^{1 to} R ⁵ may have a substituent. Examples of such a substituent include a halogen atom, 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 3 carbon atoms. Examples thereof include a cycloalkyl group having 10 or less or a heterocyclic group having 3 to 14 carbon atoms.

In general formula (1), the aralkyl group having 7 to 20 carbon atoms represented by R ^{1 to} R ⁵ may have a substituent. Examples of such a substituent include a halogen atom, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or a carbon atom. A heterocyclic group having a number of 3 or more and 14 or less is exemplified.

In general formula (1), R ¹ , R ² , R ³ , R ⁴ , and R ⁵ are each independently an alkyl group having 1 to 3 carbon atoms and the number of carbon atoms that may have a substituent. It preferably represents an aryl group of 6 or more and 14 or less, or a hydrogen atom. The substituent that the aryl group may have is preferably one or more alkyl groups having 1 to 3 carbon atoms, one or more alkoxy groups having 1 to 3 carbon atoms, or a halogen atom. . n preferably represents 1 or 2.

In general formula (1), R ⁴ preferably represents an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 14 carbon atoms which may have a halogen atom.

Examples of the enamine derivative (1) include the enamine derivative (1) shown in Table 1 (specifically, enamine derivatives (HTM-1) to (HTM-23)). In Table 1, HTM represents a hole transport agent. HTM-1 to HTM-23 in the column “HTM” represent enamine derivatives (HTM-1) to (HTM-23), respectively. The abbreviations in the columns “R ^{1 to} R ⁵ ” represent the following substituents.
Ph: phenyl group Me: methyl group p-Me-Ph: p-methylphenyl group p, o-Me, Et-Ph: o-ethyl-p-methylphenyl group p-OEt-Ph: p-ethoxyphenyl group o , P-diOMePh: o, p-dimethoxyphenyl group p-Cl-Ph: p-chlorophenyl group p-F-Ph: p-fluorophenyl group

  Enamine derivatives (HTM-1) to (HTM-4), (HTM-6) to (HTM-9), (HTM-11), (HTM-14), (HTM-17), and (HTM-20) Among them, from the viewpoint of further suppressing the generation of transfer memory, enamine derivatives (HTM-1) to (HTM-2), (HTM-4), (HTM-6), (HTM-9), (HTM-11) ), (HTM-14), or (HTM-17) is preferred. Enamine derivatives (HTM-1) to (HTM-4), (HTM-6) to (HTM-9), (HTM-11), (HTM-14), (HTM-17), and (HTM-20) Among these, enamine derivatives (HTM-1) to (HTM-2), (HTM-4), (HTM-6) from the viewpoint of further suppressing the generation of transfer memory and further improving the filming resistance of the photoreceptor. ), (HTM-9), (HTM-11), (HTM-14), or (HTM-17) is preferred.

  The photosensitive layer may contain another hole transporting agent in addition to the enamine derivative (1). As another 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.), Dorazon 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.

  When the photoreceptor is a single layer type photoreceptor, the content of the hole transport agent is 10 parts by mass or more and 200 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 100 parts by mass or less, and particularly preferably 10 parts by mass or more and 75 parts by mass or less.

  When the photoreceptor is a multilayer photoreceptor, the content of the hole transport agent is preferably 10 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the binder resin contained in the charge transport layer. More preferably, it is 20 parts by mass or more and 100 parts by mass or less.

[6. Charge generator]
When the photoreceptor is a multilayer photoreceptor, the charge generation layer contains a charge generation agent. When the photoreceptor is a single layer type photoreceptor, the single layer type photosensitive layer contains a charge generating agent.

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

  Examples of the phthalocyanine pigment include titanyl phthalocyanine or metal phthalocyanine represented by the chemical formula (CGM-A). 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 may be described as 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, it is preferable to use a photoconductor having sensitivity in a wavelength region of 700 nm or more. Examples of the digital optical image forming apparatus include a laser beam printer or a facsimile using a light source such as a semiconductor laser. 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 enamine derivative (1), the charge generator is X-type metal-free phthalocyanine, α-type titanyl phthalocyanine crystal, or Y-type titanyl phthalocyanine. Crystals are more preferred, and Y-type titanyl phthalocyanine crystals are particularly preferred. In order to further improve the filming resistance of the photoreceptor and further suppress the generation of transfer memory when the photosensitive layer contains the enamine derivative (1), X-type metal-free phthalocyanine, α A type titanyl phthalocyanine crystal or a Y type titanyl phthalocyanine crystal is more preferable, and a Y type titanyl phthalocyanine crystal is particularly preferable.

  The Y-type titanyl phthalocyanine crystal has a main peak at 27.2 ° of the Bragg angle (2θ ± 0.2 °) in the CuKα characteristic X-ray diffraction spectrum, for example. 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 ° of the Bragg angle (2θ ± 0.2 °) in the CuKα characteristic X-ray diffraction spectrum, for example.

(Measuring method of CuKα characteristic X-ray diffraction spectrum)
An example of 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 (for example, “RINT (registered trademark) 1100” manufactured by Rigaku Corporation), an X-ray tube Cu, a tube voltage 40 kV, a tube current 30 mA, and CuKα. An X-ray diffraction spectrum is measured under the condition of a characteristic X-ray wavelength of 1.542 mm. The measurement range (2θ) is, for example, 3 ° to 40 ° (start angle 3 °, stop angle 40 °), and the scanning speed is, for example, 10 ° / min.

  For the photoreceptor applied to the image forming apparatus using the short wavelength laser light source, Ansanthrone pigment is preferably used as the charge generating agent. 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 particularly preferably 0.5 parts by mass or more and 4.5 parts by mass or less.

  When the photoreceptor is a multilayer photoreceptor, the content of the charge generating agent is preferably 5 parts by mass or more and 1000 parts by mass or less with respect to 100 parts by mass of the base resin contained in the charge generation layer. More preferably, it is at least 500 parts by mass.

[7. 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 layer or a polyarylate resin is preferable because a single-layer type photosensitive layer and a charge transport layer having an excellent balance of workability, mechanical strength, optical properties, and abrasion resistance can be obtained. . Further, from the viewpoint of good compatibility with the enamine derivative (1) and improving the dispersibility of the enamine derivative (1) in the photosensitive layer, the binder resin contains a repeating unit represented by the general formula (3). A polycarbonate resin having a repeating unit represented by the general formula (4) (hereinafter referred to as a polycarbonate resin (3)) or a polyarylate resin having a repeating unit represented by the general formula (4) (hereinafter referred to as a polyarylate resin (4)). ) Is more preferable.

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 as or different from each other.

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 General Formula (3), R ¹³ and R ¹⁴ preferably represent a hydrogen atom, a methyl group, or a methyl group that may have a halogen atom, and represent a hydrogen atom, a methyl group, or a methyl fluoride group. It is more preferable that it represents a hydrogen atom or 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. From the viewpoint of further improving the filming resistance of the photoreceptor, it is preferable that at least one of R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ in the general formula (4) has one or more halogen atoms. . In the general formula (4), the substitution positions of the two carbonyl groups are the ortho position (o position), meta position (m position), para position (p position) on the benzene ring having the two carbonyl groups. ). The substitution position of these two carbonyl groups is preferably the para position.

  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 photoreceptor contains the enamine derivative (1) as a hole transport agent, from the viewpoint of further improving the filming resistance of the photoreceptor, the binder resin is a polycarbonate resin (PC-1), (PC-2), ( PC-4) and (PC-5) are preferred. When the photoreceptor contains the enamine derivative (1) as a hole transport agent, from the viewpoint of further improving the filming resistance of the photoreceptor and further suppressing the occurrence of transfer memory, the binder resin is a polycarbonate resin (PC- 1), (PC-2), (PC-4), and (PC-5) are preferable.

  The viscosity average molecular weight of the binder resin is preferably 25,000 or more, more preferably 30,000 or more and 70,000 or less, and more preferably 48,500 or more and 50,000 or less. When the viscosity average molecular weight of the binder resin is 30,000 or more, it is easy to improve the abrasion resistance of the photoreceptor. When the viscosity average molecular weight of the binder resin is 70,000 or less, the binder resin is easily dissolved in a solvent during formation of the photosensitive layer, and the viscosity of the charge transport layer coating solution or single layer type photosensitive layer coating solution is increased. Not too much. As a result, it becomes easy to form a charge transport layer or a single-layer type photosensitive layer.

[8. Filler particles]
The filler particles are silica particles or resin particles. As the resin of the resin particles, for example, silicone resin, polyphenylene sulfide resin (hereinafter, may be referred to as PFS resin), or Poritetorafu Le Oroechiren resin (hereinafter, may be referred to as PTFE resin) and the like. From the viewpoint of further suppressing the generation of the transfer memory, the filler particles are preferably resin particles, and more preferably contain a silicone resin or a PTFE resin. From the viewpoint of further improving the filming resistance of the photoreceptor, the filler particles are preferably resin particles, more preferably contain silicone resin or PTFE resin, and more preferably contain PTFE resin. From the viewpoint of further improving the filming resistance of the photoreceptor and further improving the generation of transfer memory, the filler particles are preferably resin particles, more preferably containing a silicone resin or PTFE resin, and more preferably containing a PTFE resin. Further preferred. 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 5 nm or more and 10 μm or less, and more preferably 0.40 μm or more and 10 μm or less from the viewpoint of further suppressing the generation of the transfer memory. The volume median diameter D ₅₀ of the filler particles is preferably from 5 nm to 10 μm, more preferably from 0.40 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 D ₅₀ of the filler particles is preferably 5 nm or more and 10 μm or less, and more preferably 0.40 μm or more and 10 μm from the viewpoint of further improving the filming resistance of the photoreceptor and further suppressing the generation of transfer memory. Or less, more preferably 1.0 μm or more and 10 μm or less. The volume median diameter D ₅₀ 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 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 single-layer type photosensitive layer or the charge transport layer. From the viewpoint of further improving the filming resistance of the photoreceptor, the content of the filler particles is more preferably 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin. More preferably, it is at most parts. From the viewpoint of further improving the filming resistance of the photoreceptor and further suppressing the generation of transfer memory, the content of the filler particles is 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin. Is more preferable, and it is still more preferable that they are 3 to 10 mass parts.

[9. Base resin]
When the photoreceptor is a multilayer photoreceptor, the charge generation layer contains a base resin. The base resin is not particularly limited as long as it is a base resin applicable to the photoreceptor. Examples of the base resin include a thermoplastic resin, a thermosetting resin, and a photocurable resin. Examples of the thermoplastic resin include styrene-butadiene resin, styrene-acrylonitrile resin, styrene-maleic acid resin, styrene-acrylic acid resin, acrylic resin, polyethylene resin, ethylene-vinyl acetate resin, chlorinated polyethylene resin, poly Vinyl chloride resin, polypropylene resin, ionomer, vinyl chloride-vinyl acetate resin, alkyd resin, polyamide resin, urethane resin, polycarbonate resin, polyarylate resin, polysulfone resin, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin or A polyester resin is mentioned. Examples of the thermosetting resin include silicone resins, epoxy resins, phenol resins, urea resins, melamine resins, and other crosslinkable thermosetting resins. Examples of the photocurable resin include an epoxy-acrylic acid resin (more specifically, an acrylic acid derivative adduct of an epoxy compound) or a urethane-acrylic acid resin (more specifically, an acrylic acrylic resin). Acid derivative adducts, etc.). A base resin may be used individually by 1 type, and may be used in combination of 2 or more type.

  The base resin contained in the charge generation layer is preferably different from the binder resin contained in the charge transport layer. This is because the charge generation layer is not dissolved in the solvent of the charge transport layer coating solution. In the production of a layered photoreceptor, it is common to form a charge generation layer on a conductive substrate and form a charge transport layer on the charge generation layer. This is because when forming the charge transport layer, a charge transport layer coating solution is applied onto the charge generation layer.

[10. Additive]
The photosensitive layer (charge generation layer, charge transport layer, or single layer type photosensitive layer) of the photoreceptor 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.

[11. Middle layer]
The intermediate layer (undercoat layer) contains, for example, inorganic particles and a resin (interlayer 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.

[12. Photoconductor manufacturing method]
Next, when the photoreceptor is a single-layer photoreceptor, the single-layer photoreceptor is produced, for example, by applying a coating solution for a single-layer photosensitive layer on a conductive substrate and drying. The coating solution for the single-layer type photosensitive layer is added, for example, as necessary, a charge generator, an enamine derivative (1) as a hole transport agent, an electron transport agent, a binder resin, filler particles, and the like. It is prepared by dissolving or dispersing the additive in a solvent.

  When the photoreceptor is a multilayer photoreceptor, the multilayer photoreceptor is manufactured, for example, as follows. First, a charge generation layer coating solution and a charge transport layer coating solution are prepared. A charge generation layer is formed by applying a coating solution for charge generation layer onto a conductive substrate and drying. Subsequently, the charge transport layer coating liquid is applied on the charge generation layer and dried to form the charge transport layer. Thereby, a laminated photoreceptor is manufactured.

  The charge generation layer coating solution is prepared, for example, by dissolving or dispersing a charge generation agent, a base resin, and an additive added as necessary in a solvent. The coating solution for the charge transport layer is prepared by dissolving an enamine derivative (1) as a hole transport agent, an electron acceptor compound, a binder resin, filler particles, and an additive added as necessary in a solvent. Prepared by dispersing.

  The solvent contained in the coating solution for charge generation layer, the coating solution for charge transport layer or the coating solution for single layer type photosensitive layer (hereinafter sometimes referred to as coating solution) dissolves each component contained in the coating solution. Or as long as it can disperse | distribute, it does not specifically limit. Examples of the solvent include alcohol (more specifically, methanol, ethanol, isopropanol, or butanol), aliphatic hydrocarbon (more specifically, n-hexane, octane, cyclohexane, etc.), aromatic carbonization, and the like. Hydrogen (more specifically, benzene, toluene, xylene, etc.), halogenated hydrocarbon (more specifically, dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene, etc.), ether (more specifically, dimethyl ether) , Diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, or propylene glycol monomethyl ether), ketones (more specifically, acetone, methyl ethyl ketone, cyclohexanone, etc.), esters (more The manner, 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>
Hereinafter, an aspect of the image forming apparatus according to the second embodiment will be described with reference to FIG. FIG. 3 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. When the transfer memory is generated in the image forming process as described above, when the circumference of the photoconductor in the image formation is used as a reference (hereinafter sometimes referred to as a reference circumference), the surface of the image carrier 30 has a reference circumference. The region where the desired potential cannot be obtained in the charging process of the next circumference tends to be lower than the area where the desired potential can be obtained in the charging process of the next circumference of the reference circumference. Specifically, the non-exposure area around the reference circumference on the surface of the image carrier 30 tends to have a lower potential when charging the next circumference around the reference circumference than the exposure area around the reference circumference. For this reason, the non-exposure area around the reference circumference tends to lower the potential during charging compared to the exposure area around the reference circumference, so that it becomes easier to attract positively charged toner during development. 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. 4, an image in which an image defect has occurred will be described. FIG. 4 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 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. 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 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.

  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 caused by 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>
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 portion. The unitized portion is an image carrier 30. The unitized portion may include 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 in addition to the image carrier 30. 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, and filler particles were prepared as materials for forming the single layer type photosensitive layer of the single layer type photoreceptor.

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

[1-2. Hole transport agent]
Hole transport agents (HTM-1) to (HTM-4), (HTM-6) to (HTM-9), (HTM-11), (HTM-14), (HTM-) described in the first embodiment 17) and (HTM-20) were prepared.

  Further, hole transport agents represented by chemical formulas (HTM-A), (HTM-B), and (HTM-C) (hereinafter referred to as hole transport agents (HTM-A), (HTM-B), and (It may be described as (HTM-C)).

[1-3. Charge generator]
[1-3-1. Y-type titanyl phthalocyanine crystal]
The charge generating agents (CGM-1), (CGM-2), and (CGM-3) described in the first embodiment were prepared. The charge generating agent (CGM-1) was titanyl phthalocyanine represented by the chemical formula (CGM-A), and the crystal structure was a known 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.

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

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

  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.

[1-4. Binder resin]
Polycarbonate resins (PC-1) to (PC-5) described in the first embodiment as binder resins (viscosity average molecular weights are 50,000, 48,500, 49,800, 50,000, and 50,000, respectively) And polyarylate resin (PAR-1) (viscosity average molecular weight 50,000).

[1-5. Filler particles]
Table 2 shows the filler particles used in Examples and Comparative Examples. Table 2 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 2 are registered trademarks. In Table 2, 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.

<2. Manufacture of photoconductor>
Photoconductors (A-1) to (A-32) and photoconductors (B-1) to (B-5) were produced using materials for forming the photosensitive layer.

[2-1. Production of photoconductor (A-1)]
Charge generator (CGM-1) 3 parts by mass, enamine derivative (HTM-1) 60 parts by mass as a hole transport agent, compound (ETM1-1) 40 parts by mass as an electron transport agent, filler particles F7: 5 parts by mass Part, 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 single layer type photosensitive layers. The single-layer photosensitive layer coating solution was coated on an aluminum drum-shaped support as a conductive substrate using a dip coating method. The applied coating liquid for single-layer type photosensitive layer 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-32) and photoconductors (B-1) to (B-5)]
The photoconductors (A-2) to (A-32) and the photoconductors (B-1) to (B-4) 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 type of charge generating agent shown in Tables 3-4. The compound (ETM1-1) as the electron transport agent used for the production of the photoreceptor (A-1) was changed to the type of electron transport agent shown in Tables 3-4. The enamine derivative (HTM-1) as the hole transporting agent used for the production of the photoreceptor (A-1) was changed to the types of hole transporting agents shown in Tables 3 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 3 to 4, respectively. The polycarbonate resin (PC-1) as the binder resin used for the production of the photoreceptor (A-1) was changed to the type of binder resin shown in Tables 3-4.

  Tables 3 to 4 show the structures of the photoreceptors (A-1) to (A-32) and the photoreceptors (B-1) to (B-5). In Tables 3 to 4, CGM, HTM, and ETM represent a charge generator, a hole transport agent, and an electron transport agent, respectively. In Tables 3 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)). In Tables 3 to 4, HTM-1 to HTM-4, HTM-6 to HTM-9, HTM-11, HTM-14, HTM-17, and HTM-20 in the HTM column are enamine derivatives (HTM-1 ) To (HTM-4), (HTM-6) to (HTM-9), (HTM-11), (HTM-14), (HTM-17), and (HTM-20). In Tables 3 to 4, ETM1-1, ETM2-1, ETM3-1, ETM4-1, and ETM5-1 in the ETM column are the compounds (ETM1-1), (ETM2-1), and (ETM3-1), respectively. , (ETM4-1), and (ETM5-1). In Tables 3 to 4, F1, F3, F4, F6, F7, and F9 to F11 in the kind column of filler particles indicate filler particles F1, F3, F4, F6, F7, and F9 to F11, respectively. In Tables 3-4, PC-1 to PC-5 and PAR-1 in the type of binder resin 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-32) and the photoreceptors (B-1) to (B-5). 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 an evaluation machine, an image forming apparatus (“FS-C5250DN” modified machine manufactured by Kyocera Document Solutions Co., Ltd.) was used. This evaluation machine adopted a direct transfer system. 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 of 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. 5 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 photoconductor, 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 _T : An image ghost corresponding to the image 76 was not observed.
Evaluation B _T : Image ghost corresponding to the image 76 was slightly observed.
Evaluation C _T : Although an image ghost corresponding to the image 76 was observed, it was a level with no practical problem.
Evaluation D _T : An image ghost corresponding to the image 76 was clearly observed, and it was at 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-32) and the photoreceptors (B-1) to (B-5). 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 check for the presence 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 5-6. In addition, evaluation AC was set as the pass.

(Filming resistance evaluation criteria)
Evaluation A _F : Muscles and dash marks were not observed.
Evaluation B _F : Slight muscles and dashes were observed.
Evaluation C _F : Although streaks and dash marks were partially observed, they were at a level having no practical problem.
Evaluation D _F : 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 was evaluation _AT and the evaluation result of the filming resistance was evaluation _AF .
Evaluation B: evaluation of the transfer memory is rated A _T a is either filming resistance evaluation result is rated B _F, evaluation results of evaluation of the transfer memory B _T a and filming resistance evaluation results are rated A or is _F, the evaluation result of the transfer memory is rated B _T a and filming resistance evaluation results were rated B _F.
Evaluation C: The evaluation result of the transfer memory was not evaluation _DT , and the evaluation result of filming resistance was not evaluation _DF . Or evaluation of the transfer memory is rated C _T, or filming resistance evaluation result is rated C _F, an evaluation result of the transfer memory is rated C _T, and filming resistance evaluation results of evaluation was C _F.
Evaluation D: The evaluation result _DT of the transfer memory evaluation result, and the evaluation result of the filming resistance was evaluation _DF .

  As shown in Tables 3 and 4, in the photoreceptors (A-1) to (A-32), the photosensitive layer has a charge generating agent, a hole transporting agent, an electron transporting agent, filler particles, and a binder resin. And contained. Specifically, the hole transport agent was an enamine derivative (1). The enamine derivative (1) is represented by the general formula (1). The filler particles were any one of F1, F3 to F4, F6 to F7, and F9 to F10.

  As shown in Table 5, in the photoreceptors (A-1) to (A-32), the overall evaluation result of the transfer memory and the filming resistance was any one of A, B, and C.

  As shown in Table 4, in the photoreceptor (B-1), the photosensitive layer did not contain filler particles. In the photoreceptors (B-2) to (B-4), the photosensitive layer has any one of a hole transport agent (HTM-A), (HTM-B), and (HTM-C) as a hole transport agent. Included. Hole transport agents (HTM-A), (HTM-B), and (HTM-C) were not enamine derivatives (1). In the photoreceptor (B-5), the photosensitive layer contained filler particles F11. The filler particles F11 were neither silica particles nor resin particles.

  As shown in Table 6, in the photoreceptors (B-1) to (B-5), the overall evaluation results of the transfer memory and the filming resistance were all D.

  The photoconductors (A-1) to (A-32) suppress generation of transfer memory and are excellent in filming resistance as compared with the photoconductors (B-1) to (B-5).

  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 3b Charge generation layer 3c Charge transport layer

Claims (16)

An electrophotographic photosensitive member comprising a conductive substrate and a photosensitive layer,
The photosensitive layer includes a charge generator, an enamine derivative, an electron transport agent or an electron acceptor compound, a binder resin, and filler particles.
The enamine derivative is represented by the general formula (1),
The electrophotographic photoreceptor, wherein the filler particles are resin particles containing a polytetrafluoroethylene resin .

In the general formula (1),
R ¹ and R ² are each independently an alkyl group having 1 to 6 carbon atoms which may have a substituent, an alkoxy 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 plurality of substituents, an aryloxy group having 6 to 14 carbon atoms which may have a substituent, and a substituent. Represents an aralkyl group having from 7 to 20 carbon atoms, a halogen atom, or a hydrogen atom,
R ³ represents a phenyl group, a p-methylphenyl group, or a p-methoxyphenyl group,
R ⁴ represents a phenyl group, a p-methylphenyl group, or a p-chlorophenyl group,
R ⁵ represents a p-methylphenyl group or a hydrogen atom,
When both R ⁴ and R ⁵ represent a p-methylphenyl group, R ¹ , R ² and R ³ all represent a p-methylphenyl group,
n represents 1 or 2 . In the general formula (1),
R ¹ and R ² each independently represents 1 or more carbon atoms of 3 or less alkyl group, having 6 or more carbon atoms which may have a substituent group 14 following aryl group, or a hydrogen atom,
The aryl group wherein the substituent that may be possessed by the Ru Ah 1 or more carbon atom number of 1 to 3 alkyl groups, one or more carbon atoms from 1 to 3 alkoxy groups, or halogen atoms The electrophotographic photosensitive member according to claim 1. The electrophotographic photosensitive member according to claim 1, wherein the charge generating agent includes a Y-type titanyl phthalocyanine crystal.   The electrophotographic photosensitive member according to claim 1, wherein the filler particles have a volume median diameter of 5 nm to 10 μm.   5. The electrophotographic photosensitive member according to claim 1, wherein a 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 electrophotographic photosensitive member according to claim 1, wherein the electron transfer agent or the electron acceptor compound includes a compound represented by a chemical formula (ETM1-1).

The electrophotographic photosensitive member according to claim 1, wherein the binder resin has a repeating unit represented by General Formula (3) or 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 as 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,
The electrophotographic photosensitive member according to claim 7, wherein R ¹⁷ and R ¹⁸ 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 (PC-5). The electrophotographic photosensitive member according to 7 or 8.

The photosensitive layer is a single-layer type photosensitive layer, the electrophotographic photosensitive member according to any one of claims 1-9. The electrophotographic image according to any one of claims 1 to 10 , wherein the photosensitive layer is disposed directly on the conductive substrate, or indirectly through an undercoat layer or an oxide film. Photoconductor. 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 11 ,
The transfer unit is an image forming apparatus that 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 image forming apparatus according to claim 12 , wherein the charging unit charges the surface of the image carrier while being in contact with the surface of the image carrier. The developer comprises a polymerized toner, the image forming apparatus according to claim 12 or 13. A cleaning unit;
The cleaning unit is a cleaning blade, an image forming apparatus according to any one of claims 12-14. A process cartridge comprising the electrophotographic photosensitive member according to any one of claims 1 to 11 .

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