JP6638612B2 - Electrophotographic photosensitive member, image forming apparatus, and process cartridge - Google Patents

Description

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

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

  The photosensitive layer included in the electrophotographic photosensitive member described in Patent Document 1 contains, for example, a compound represented by the following chemical formula (ET-4).

  The photosensitive layer included in the electrophotographic photosensitive member described in Patent Document 2 contains, for example, a compound represented by the following chemical formula (ET-3).

JP 2005-154444 A JP 2005-173292 A

  However, the electrophotographic photosensitive members described in Patent Documents 1 and 2 have excellent filming resistance and cannot sufficiently suppress the occurrence of transfer memory.

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

  The electrophotographic photoreceptor of the present invention includes a conductive substrate and a photosensitive layer. The photosensitive layer includes a charge generating agent, a hole transporting agent, at least one selected from the group consisting of a quinone derivative and a diimide derivative, a binder resin, and one or more filler particles. The quinone derivative is represented by the general formula (1). The diimide derivative is represented by the general formula (2). The one or more filler particles are silica particles or resin particles.

In the general formula (1), R ¹ may have an alkyl group having 1 or more and 8 or less carbon atoms, which may have one or more substituents, or an alkyl group having 1 or more and 6 or less carbon atoms. It represents a first group selected from the group consisting of a good aryl group having 6 to 14 carbon atoms and a cycloalkyl group having 3 to 20 carbon atoms. The first group is substituted with one or more halogen atoms. Two R ¹ may be the same or different from each other. R ² is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an aryl group having 6 to 14 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or And represents a heterocyclic group having 3 to 14 carbon atoms which may have a substituent. Two R ² may be the same or different from each other.

In the general formula (2), R ³ and R ⁴ each independently represent an alkyl group having 1 to 6 carbon atoms and a phenylcarbonyl group, which may have any of 6 to 14 carbon atoms. Represents an aryl group, an aralkyl group having 7 to 20 carbon atoms, an alkyl group having 1 to 8 carbon atoms, and a cycloalkyl group having 3 to 10 carbon atoms. . The second group may be substituted with one or more halogen atoms. At least one of R ³ and R ⁴ has one or more halogen atoms.

  The image forming apparatus according to the present invention includes an image carrier, a charging unit, an exposure unit, a development unit, and a transfer unit. The image bearing member is the above-described electrophotographic photosensitive member. The charging unit charges the surface of the image carrier. The charging portion has a positive polarity. The exposure section 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 a recording medium while the surface of the image carrier is in contact with the recording medium.

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

  ADVANTAGE OF THE INVENTION According to the electrophotographic photosensitive member of this invention, it is excellent in filming resistance and can suppress generation | occurrence | production of a transfer memory. Further, according to the image forming apparatus and the process cartridge of the present invention, occurrence of an image defect can be suppressed.

(A), (b) and (c) are schematic sectional views each showing an example of the electrophotographic photosensitive member according to the first embodiment of the present invention. (A), (b) and (c) are schematic sectional views each showing another example of the electrophotographic photosensitive member according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating an example of an image forming apparatus according to a second embodiment of the present invention. FIG. 3 is a diagram illustrating an image in which an image ghost has occurred. ^{1 is} a ¹ H-NMR spectrum of a quinone derivative (1-1). It is a < ¹ > H-NMR spectrum of a diimide derivative (2-1). It is a figure showing an 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 present invention. In addition, although the description may be omitted as appropriate for portions where the description is duplicated, the gist of the invention is not limited.

  Hereinafter, a compound and its derivative may be generically referred to by adding “system” after the compound name. Further, when a polymer name is indicated by adding “system” after the compound name, it means that the repeating unit of the polymer is derived from the compound or its derivative.

  A halogen atom, an alkyl group having 1 to 8 carbon atoms, 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, carbon atom Alkyl group having 2 to 4 atoms, alkyl group having 1 to 3 carbon atoms, alkoxy group having 1 to 8 carbon atoms, alkoxy group having 1 to 4 carbon atoms, 6 to 14 carbon atoms Aryl group, an aralkyl group having 7 to 20 carbon atoms, an aralkyl group having 7 to 9 carbon atoms, a heterocyclic group having 3 to 14 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, The cycloalkylidene group having 5 or more and 7 or less carbon atoms has the following meanings, respectively, unless otherwise specified.

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

  The alkyl group having 1 to 8 carbon atoms is linear or branched and is unsubstituted. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an s-butyl group, a t-butyl group, a pentyl group, an isopentyl group, Examples include a neopentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group.

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

  The alkyl group having 1 to 5 carbon atoms is linear or branched and is unsubstituted. Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an s-butyl group, a t-butyl group, a pentyl group, an isopentyl group, Or a neopentyl group.

  The alkyl group having 1 to 4 carbon atoms is linear or branched and is 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 2 or more and 4 or less carbon atoms is linear or branched and is unsubstituted. Examples of the alkyl group having 2 or more and 4 or less carbon atoms include 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 3 carbon atoms is straight-chain or branched and is 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 alkoxy group having 1 to 8 carbon atoms is linear or branched and unsubstituted. Examples of the alkoxy group having 1 to 8 carbon atoms include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, s-butoxy, t-butoxy, pentyloxy, Examples include a pentyloxy group, a neopentyloxy group, a hexyloxy group, a heptyloxy group, and an octyloxy group.

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

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

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

  An aralkyl group having 7 to 9 carbon atoms is unsubstituted. The aralkyl group having 7 to 9 carbon atoms is a group in which a phenyl group is bonded to an alkyl group having 1 to 3 carbon atoms. Examples of the aralkyl group having 7 to 9 carbon atoms include a phenylmethyl group, a 2-phenylethyl group, and a 1-phenylethyl group.

  A heterocyclic group having 3 to 14 carbon atoms is unsubstituted. Examples of the heterocyclic group having 3 to 14 carbon atoms include an aromatic 5- or 6-membered monocyclic heterocyclic ring containing one or more (preferably 1 to 3) heteroatoms. A heterocyclic group in which such single rings are fused; or a heterocyclic group in which such a single ring is fused with a 5- 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-quinolizinyl group, naphthyridinyl group, Examples include a benzofuranyl group, a 1,3-benzodioxolyl group, a benzoxazolyl group, a benzothiazolyl group, and a benzimidazolyl group.

  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.

  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.

<First Embodiment: Electrophotographic Photoreceptor>
The first embodiment of the present invention relates to an electrophotographic photosensitive member (hereinafter, sometimes referred to as a photosensitive member). The photoconductor includes a conductive substrate and a photosensitive layer. As the photoreceptor, for example, a single-layer type electrophotographic photoreceptor (hereinafter, sometimes referred to as a single-layer type photoreceptor) or a stacked-type electrophotographic photoreceptor (hereinafter, sometimes referred to as a laminated-type photoreceptor) ).

[1. Single layer type photoreceptor]
Hereinafter, the structure of the single-layer type photoconductor will be described with reference to FIG. FIG. 1 is a schematic sectional view showing an example of the photoconductor 1 according to the first embodiment.

  In FIG. 1, the photoconductor 1 is a single-layer photoconductor. As shown in FIG. 1A, the single-layer type photoconductor includes, for example, a conductive substrate 2 and a photosensitive layer 3. The single-layer type photoconductor includes a single-layer type photosensitive layer 3 a as the photosensitive layer 3. The single-layer photosensitive layer 3a is a single photosensitive layer 3. As shown in FIG. 1A, the photosensitive layer 3 may be directly disposed 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 via the intermediate layer 4. Further, as shown in FIG. 1C, a 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 the single-layer type photosensitive layer can be sufficiently exhibited. The thickness of the single-layer type photosensitive layer 3a is preferably 5 μm or more and 100 μm or less, more preferably 10 μm or more and 50 μm or less.

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

  In FIG. 2, the photoconductor 1 is a stacked photoconductor. As shown in FIG. 2A, the stacked photoconductor 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 wear resistance of the laminated photoreceptor, as shown in FIG. 2A, a charge generation layer 3b is provided on a conductive substrate 2, and a charge transport layer 3c is provided on the charge generation layer 3b. Preferably, it is provided. As shown in FIG. 2B, in the laminated type 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. 2C, the laminated 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 exhibited. 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 from 2 μm to 100 μm, more preferably from 5 μm to 50 μm.

  The structure of the photoconductor 1 has been described above with reference to FIGS.

  The photoreceptor according to the first embodiment includes a photosensitive layer. The photosensitive layer includes a charge generating agent, a hole transporting agent, at least one selected from the group consisting of a quinone derivative and a diimide derivative, a binder resin, and one or more filler particles. In the laminated photoreceptor, the charge generation layer includes, for example, a charge generation agent and a binder resin for the charge generation agent (hereinafter, sometimes referred to as a base resin). The charge transport layer includes, for example, a hole transport agent, at least one selected from the group consisting of a quinone derivative and a diimide derivative, a binder resin, and one or more filler particles. In the single-layer type photoreceptor, the single-layer type photosensitive layer includes, for example, a charge generating agent, a hole transporting agent, at least one selected from the group consisting of quinone derivatives and diimide derivatives, a binder resin, It contains the above filler particles. The charge generation layer, the charge transport layer, and the single-layer type photosensitive layer may further contain an additive.

  The photoreceptor according to the first embodiment suppresses generation of transfer memory. The reason is presumed as follows. The photoconductor according to the first embodiment includes at least one selected from the group consisting of a quinone derivative and a diimide derivative. The quinone derivative is represented by the general formula (1) (hereinafter, the quinone derivative represented by the general formula (1) is referred to as a quinone derivative (1)). The diimide derivative is represented by the general formula (2) (hereinafter, the diimide derivative represented by the general formula (2) may be referred to as a diimide derivative (2)). The quinone derivative (1) and the diimide derivative (2) have planarity and a relatively large π-conjugated system. For this reason, the photosensitive layer has an excellent electron-accepting ability, and tends to hardly cause charges as carriers to remain in the photosensitive layer. Therefore, it is considered that the photoconductor according to the first embodiment suppresses generation of transfer memory. The method of evaluating the transfer memory will be described later in detail in Examples.

  Further, the photoconductor according to the first embodiment has excellent filming resistance. The reason is presumed as follows. First, for the sake of convenience, an image defect caused by filming in the image forming process will be described. An electrophotographic image forming apparatus includes, for example, an image carrier (photoconductor), a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit. When the image forming process employs the direct transfer method, the transfer unit transfers the toner image from the photoconductor to the recording medium. After the transfer, the cleaning unit cleans the surface of the photosensitive layer 3.

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

  In the photoreceptor according to the first embodiment, in the photosensitive layer, the quinone derivative (1) and the diimide derivative (2) have a halogen atom. Therefore, if the photosensitive layer contains at least one selected from the group consisting of the quinone derivative (1) and the diimide derivative (2), even if the recording medium rubs against the surface of the photoreceptor at the transfer portion, Has the same polarity as the charging polarity of the photoreceptor and tends to have less charging property, and has a tendency to be less likely to be reversely charged. Therefore, electrostatic attraction is less likely to occur between the minute components and the surface of the photosensitive layer, and the minute components are less likely to adhere to the surface of the photosensitive layer. Further, the photosensitive layer contains one or more filler particles. For this reason, the photosensitive layer tends to form irregularities on its surface, and the contact area between the surface of the photosensitive layer and the minute components tends to be small. If 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 has excellent filming resistance.

  Hereinafter, a conductive substrate, an electron transporting agent, an electron acceptor compound, a hole transporting 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. Also, a method for manufacturing the photoconductor will be described.

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

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

[4. Electron transport agent, electron acceptor compound]
In the single-layer type photosensitive member, the single-layer type photosensitive layer contains at least one selected from the group consisting of a quinone derivative (1) and a diimide derivative (2) as an electron transporting agent. In the multilayer photoconductor, the charge transport layer contains at least one selected from the group consisting of a quinone derivative (1) and a diimide derivative (2) as an electron acceptor compound.

[4-1. Quinone derivative (1)]
The quinone derivative is represented by the general formula (1).

In the general formula (1), R ¹ may have an alkyl group having 1 or more and 8 or less carbon atoms, which may have one or more substituents, or an alkyl group having 1 or more and 6 or less carbon atoms. Represents a first group selected from the group consisting of an aryl group having 6 to 14 carbon atoms and a cycloalkyl group having 3 to 20 carbon atoms. The first group is substituted with one or more halogen atoms. Two R ¹ may be the same or different from each other. R ² is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an aryl group having 6 to 14 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or And represents a heterocyclic group having 3 to 14 carbon atoms which may have a substituent. Two R ² may be the same or different from each other.

In general formula (1), the alkyl group having 1 to 8 carbon atoms represented by R ¹ is preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 2 to 4 carbon atoms, An ethyl group, an isopropyl group, or a tert-butyl group is more preferred. The alkyl group having 1 to 8 carbon atoms may have one or more substituents. Examples of such a substituent include a halogen atom, or an aryl group having 6 to 14 carbon atoms that may have a halogen atom, and has a fluorine atom, a chlorine atom, or a fluorine atom or a chlorine atom. A phenyl group is preferred. When the aryl group having 6 to 14 carbon atoms is a phenyl group, the substitution position of the halogen atom in the phenyl group is, for example, with respect to the position at which the phenyl group is bonded to the alkyl group having 1 to 8 carbon atoms. An ortho position (o position), a meta position (m position), a para position (p position), or at least two of them are preferable, and a para position is preferable. The alkyl group having 1 or more and 8 or less carbon atoms having one or more substituents is selected from the group consisting of an aryl group having 6 or more and 14 or less carbon atoms substituted with a halogen atom and one or more halogen atoms. An alkyl group having 1 or more and 5 or less carbon atoms having one or more tertiary groups is preferable, and an alkyl group having 2 or more and 4 or less carbon atoms having one or more tertiary groups is more preferable. 1,1-dimethylethyl group, 2,2,2-trichloro-1,1-dimethylethyl group, 1,1-dimethyl-1- (4-chlorophenyl) methyl group, 1- (4-chlorophenyl) ethyl group, -Chloro-1-phenylethyl, 2-chloro-1- (4-chlorophenyl) ethyl or 1- (4-fluorophenyl) ethyl is more preferred, and 2-chloro-1,1-dimethyl is preferred. Ethyl group, 1,1-dimethyl-1- (4-chlorophenyl) methyl group, 1- (4-chlorophenyl) ethyl group, 2-chloro-1-phenylethyl group, 2-chloro-1- (4-chlorophenyl) An ethyl group or a 1- (4-fluorophenyl) ethyl group is particularly preferred.

In the general formula (1), the alkyl group having 1 to 6 carbon atoms represented by R ² may have a substituent. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, and a cyano group. In the general formula (1), the heterocyclic group having 3 to 14 carbon atoms represented by R ² may have a substituent. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a cyano group.

In the general formula (1), R ¹ preferably represents an alkyl group having 1 to 5 carbon atoms which may have an aryl group having 6 to 14 carbon atoms. Such an aryl group having 6 to 14 carbon atoms or an alkyl group having 1 to 5 carbon atoms is preferably substituted with one or more halogen atoms. Preferably, the two R ¹ are the same. R ² preferably represents a hydrogen atom. Preferably, the two R ² are the same as each other.

In the general formula (1), the number of halogen atoms included in the first group of two R ¹ represents the total number of the number of halogen atoms included in the first base represented by the two R ² are, the sensitivity characteristic of the photosensitive member From the viewpoint of further improving and further suppressing the occurrence of transfer memory, the number is preferably 4 or more.

  As specific examples of the quinone derivative (1), quinone derivatives represented by the chemical formulas (1-1) to (1-7) (hereinafter, referred to as quinone derivatives (1-1) to (1-7)) may be used. Is).

[4-2. Method for producing quinone derivative (1)]
The quinone derivative (1) is, for example, a reaction formula (R1-1) represented by the reaction formula (R1-1) and a reaction formula (R1-2) represented by the reaction formula (R1-2). Hereinafter, it may be described as the reaction (R1-2)) or by a method analogous thereto. The method for producing the quinone derivative (1) includes, for example, a reaction (R1-1) and a reaction (R1-2).

In the reaction (R1-1), R ¹ and R ² are the same meanings as R ¹ and R ² in the general formula (1).

In the reaction (R1-1), one equivalent of the compound (naphthol derivative) represented by the chemical formula (A1) (hereinafter, may be referred to as a naphthol derivative (A1). In the general formula (1), R ¹ When a represents a hydrogen atom, the naphthol derivative (A1) represents naphthol) and 1 equivalent of the compound represented by the general formula (B1) (alcohol derivative) (hereinafter sometimes referred to as an alcohol derivative (B1)). ) In a solvent in the presence of concentrated sulfuric acid to obtain 1 equivalent of a compound represented by the general formula (C1), which is an intermediate (hereinafter sometimes referred to as a naphthol derivative (C1)). . In the reaction (R1-1), it is preferable to add 1 mol or more and 2.5 mol or less of the alcohol derivative (B1) to 1 mol of the naphthol derivative (A1). When 1 mol or more of the alcohol derivative (B1) is added to 1 mol of the naphthol derivative (A1), the yield of the naphthol derivative (C1) can be easily improved. On the other hand, when 2.5 mol or less of the alcohol derivative (B1) is added to 1 mol of the naphthol derivative (A1), the unreacted alcohol derivative (B1) hardly remains after the reaction (R1-1), and the quinone derivative Purification of (1) becomes easy. The reaction temperature of the reaction (R1-1) is preferably room temperature (for example, 25 ° C.). The reaction time of the reaction (R1-1) is preferably from 1 hour to 10 hours. Reaction (R1-1) can be performed in a solvent. Examples of the solvent include an organic acid aqueous solution (more specifically, acetic acid and the like).

  More specifically, in the reaction (R1-1), a naphthol derivative (A1) and an alcohol derivative (B1) are reacted. After the reaction, ion-exchange water is added to the reaction solution, and the mixture is extracted into an organic layer. Examples of the organic solvent contained in the organic layer include chloroform and ethyl acetate. The organic layer is added with an aqueous alkali solution, and the organic layer is washed and neutralized. Examples of the alkali include an alkali metal hydroxide (more specifically, sodium hydroxide or potassium hydroxide, etc.) or an alkaline earth metal hydroxide (more specifically, calcium hydroxide, etc.) ).

  In the reaction (R1-1), it is considered that a carbocation is generated as a reaction intermediate from the alcohol derivative (B1). For this reason, as the alcohol derivative (B1), for example, a tertiary alcohol or a secondary alcohol having an aryl group is preferable. As used herein, the term “secondary alcohol having an aryl group” means a secondary alcohol having an aryl group bonded to a carbon atom to which a hydroxyl group is bonded. In such a secondary alcohol, electrons are delocalized by the aryl group, and the carbocation is considered to be stabilized.

In the reaction (R1-2), R ¹ and R ² are the same meanings as R ¹ and R ² in the general formula (1).

In the reaction (R1-2), when two R ¹ are the same and two R ² are the same, two equivalents of the naphthol derivative (C1) are reacted in the presence of an oxidizing agent to give one equivalent The quinone derivative (1) is obtained. In the reaction (R1-2), it is preferable to add 1 mol of the oxidizing agent to 1 mol of the naphthol derivative (C1). Examples of the oxidizing agent include chloranil, potassium permanganate, and silver oxide. The reaction temperature of the reaction (R1-2) is preferably room temperature (for example, 25 ° C.). The reaction time of the reaction (R1-2) is preferably from 1 hour to 10 hours. Examples of the solvent include chloroform or dichloromethane.

In the reaction (R1-2), when at least one of the two R ¹ and the two R ² is different from each other, two equivalents of the naphthol derivative (C1) are replaced with one equivalent of the naphthol derivative (C1) and a different naphthol derivative (C1). Except having changed to 1 equivalent, the quinone derivative (1) is obtained in the same manner as in the reaction (R-2) when two R ¹ are the same and two R ² are the same.

  In the production of the quinone derivative (1), another step (for example, a purification step) may be included as necessary. Such a step includes, for example, a purification step. Examples of the purification method include a known method (more specifically, filtration, chromatography, crystallization, or the like).

[4-3. Diimide derivative (2)]
The diimide derivative (2) is represented by the general formula (2).

In the general formula (2), R ³ and R ⁴ each independently represent an alkyl group having 1 to 6 carbon atoms and a phenylcarbonyl group having 6 to 14 carbon atoms. A second group selected from the group consisting of an aryl group, an aralkyl group having 7 to 20 carbon atoms, an alkyl group having 1 to 8 carbon atoms, and a cycloalkyl group having 3 to 10 carbon atoms. The second group may be substituted with one or more halogen atoms. At least one of R ³ and R ⁴ has one or more halogen atoms.

In the general formula (2), the aryl group having 6 to 14 carbon atoms represented by R ³ and R ⁴ is preferably a phenyl group. The aryl group having 6 to 14 carbon atoms may have a substituent. Examples of such a substituent include a halogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenylcarbonyl group, and a chlorine atom, a methyl group, an ethyl group, or a phenylcarbonyl group is preferable. The number of substituents is preferably an integer of 1 or more and 3 or less. When the aryl group having 6 to 14 carbon atoms is a phenyl group, the substitution position of the substituent in the phenyl group may be, for example, an ortho position (o position), a meta position, Position (m position), para position (p position), or at least two of them. This substitution position is preferably at one ortho and para position, at two ortho positions, or at two ortho and para positions. Examples of the phenyl group having a substituent include a 4-chloro-2-phenylcarbonylphenyl group, a 2,6-dichlorophenyl group, a 2,4,6-trichlorophenyl group, and a 2-ethyl-6-methylphenyl group. No.

In the general formula (2), the aralkyl group having 7 to 20 carbon atoms represented by R ³ and R ⁴ is preferably an aralkyl group having 7 to 9 carbon atoms, and more preferably a 1-phenylethyl group. The aralkyl group having 7 to 20 carbon atoms may have a substituent. Examples of such a substituent include an alkyl group having 1 to 6 carbon atoms or a halogen atom. Examples of the aralkyl group having a halogen atom and having 7 to 20 carbon atoms include a 1- (2,4-dichlorophenyl) ethyl group.

In the general formula (2), R ³ and R ⁴ may be the same or different. When R ³ and R ⁴ are the same as each other, R ³ and R ⁴ are each an aralkyl group having 7 or more and 9 or less carbon atoms having one or more halogen atoms, or one phenylcarbonyl group and one halogen atom. It preferably represents an aryl group having 6 to 14 carbon atoms, more preferably a 1- (2,4-dichlorophenyl) ethyl group or a 4-chloro-2-phenylcarbonylphenyl group.

In the general formula (2), when R ³ and R ⁴ are different from each other, one of R ³ and R ⁴ has 6 to 14 carbon atoms having at least one alkyl group having 1 to 3 carbon atoms. Represents the following aryl group, and the other of R ³ and R ⁴ may have one or more halogen atoms, an aralkyl group having 7 or more and 9 or less carbon atoms, or a phenylcarbonyl group, Preferably represents an aryl group having a halogen atom of 6 to 14 carbon atoms.

In Formula (2), the groups represented by R ³ and R ⁴ may be substituted with one or more halogen atoms, and at least one of R ³ and R ⁴ has one or more halogen atoms. The number of halogen atoms included in the second group represented by the two R ^3, the total number of the number of halogen atoms included in the second group represented by the two R ⁴ is an integer of 1 or more. It is preferable that the total number be 1 or 2 from the viewpoint of further suppressing the occurrence of transfer memory.

  As specific examples of the diimide derivative (2), diimide derivatives represented by the chemical formulas (2-1) to (2-6) (hereinafter, diimide derivatives (2-1) to (2-6) may be described. Is).

[4-4. Method for producing diimide derivative (2)]
[4-4-1. R ¹ and R ² are different from each other]
In the general formula (2), when R ³ and R ⁴ are different from each other, the diimide derivative (2) is, for example, a reaction formula represented by a reaction formula (R2-1) or a reaction formula represented by a reaction formula (R2-2). And the reaction formula represented by the reaction formula (R2-3) (hereinafter, may be referred to as the reaction (R2-1), the reaction (R2-2), and the reaction (R2-3), respectively) or conforms thereto. Manufactured by the method. The method for producing the diimide derivative (2) includes, for example, a reaction (R2-1), a reaction (R2-2), and a reaction (R2-3).

In the reaction (R2-1), R ³ has the same meaning as R ³ in the general formula (1). R ⁵ represents an alkyl group, and preferably represents an alkyl group having 1 to 3 carbon atoms.

  In the reaction (R2-1), one molar equivalent of the compound represented by the general formula (A2) (hereinafter, sometimes referred to as compound (A2)) and one molar equivalent of the general formula (B2) are used. A compound (primary amine compound) (hereinafter, sometimes referred to as compound (B2)) is reacted in the presence of a base to give 1 molar equivalent of a compound represented by the general formula (C2) (hereinafter, referred to as a compound (B2)). Compound (C2) may be obtained). Compound (C2) is an intermediate product. In the reaction (R2-1), it is preferable to add 1 to 2.5 mol of the compound (B2) to 1 mol of the compound (A2). When 1 mol or more of the compound (B2) is added to 1 mol of the compound (A2), the yield of the compound (C2) is easily improved. On the other hand, when 2.5 mol or less of the compound (B2) is added to 1 mol of the compound (A2), the unreacted compound (B2) hardly remains after the reaction (R2-1). Purification becomes easy. The reaction temperature of the reaction (R2-1) is preferably from 80 ° C to 150 ° C. The reaction time of the reaction (R2-1) is preferably from 1 hour to 8 hours. The reaction (R2-1) can be performed in a solvent. Examples of the solvent include dioxane. The base preferably has low nucleophilicity from the viewpoint of improving the yield of the compound (C2). Such bases include, for example, N, N-diisopropylethylamine (Hünig base).

In the reaction (R2-2), R ³ has the same meaning as in formula (2) R ³ in. In the reaction (R2-2), R ⁵ has the same meaning as R ⁵ in the reaction (R2-1).

  In the reaction (R2-2), 1 molar equivalent of the compound (C2) is reacted in the presence of an acid, and 1 molar equivalent of the compound represented by the general formula (D2) (hereinafter, referred to as compound (D2)) Sometimes). Compound (D2) is an intermediate product. In the reaction (R2-2), the ester of the compound (C2) is hydrolyzed in the presence of an acid to form a dicarboxylic acid, and then the dicarboxylic acid is closed to form a carboxylic anhydride. As a result, a compound (D2) is produced. The reaction time of the reaction (R2-2) is preferably 5 hours or more and 30 hours or less. The reaction temperature of the reaction (R2-2) is preferably from 70 ° C to 150 ° C. As the acid, for example, trifluoroacetic acid is preferable. The acid may function as a solvent.

In the reaction (R2-3), R ³ and R ⁴ are the same meanings as R ³ and R ⁴ in the general formula (2).

  In the reaction (R2-3), 1 molar equivalent of the compound (D2) and 1 molar equivalent of the compound (primary amine compound) represented by the general formula (E2) (hereinafter, referred to as compound (E2) Is reacted in the presence of a base to obtain 1 molar equivalent of the diimide derivative (2). In the reaction (R2-3), it is preferable to add 1 mol or more and 2.5 mol or less of the compound (E2) to 1 mol of the compound (D2). When 1 mol or more of the compound (E2) is added to 1 mol of the compound (D2), the yield of the diimide derivative (2) is easily improved. On the other hand, when 2.5 mol or less of the compound (E2) is added to 1 mol of the compound (D2), the unreacted compound (E2) hardly remains after the reaction (R2-3), and the diimide derivative (2) Can be easily purified. The reaction temperature of the reaction (R2-3) is preferably from 80 ° C to 150 ° C. The reaction time of the reaction (R2-3) is preferably from 1 hour to 8 hours. Reaction (R2-3) can be carried out in a solvent. Examples of the solvent include dioxane. The base preferably has low nucleophilicity from the viewpoint of improving the yield of the diimide derivative (2). Such bases include, for example, N, N-diisopropylethylamine (Hünig base).

In addition, the manufacturing method of the diimide derivative (2) changes the order of imidation with the primary amine having R ¹ and the primary amine having R ² in the reactions (R2-1) to (R2-3). You may. The diimide derivative (2) is, for example, a reaction represented by the reaction formula (R'2-1), a reaction represented by the reaction formula (R'2-2), and a reaction represented by the reaction formula (R'2-3). It is also produced according to the formula (hereinafter sometimes referred to as reaction (R'2-1), reaction (R'2-2) and reaction (R'2-3), respectively) or by a method analogous thereto. .

Specifically, the reaction (R′2-1) is the same as the reaction (R2-1) except that the compound (B2) is changed to the compound (E2). Reaction (R′2-2) is a reaction (R′2-2) except that compound (C2) is changed to a compound represented by general formula (C′2) (hereinafter sometimes referred to as compound (C′2)). This is the same reaction as (R2-2). The reaction (R'2-3) changes the compound (D2) to a compound represented by the general formula (D'2) (hereinafter, sometimes referred to as a compound (D'2)), and converts the compound (E2 ) Is the same as the reaction (R2-3) except that the compound (B2) was replaced with the compound (B2). Reaction (R'2-1) in ^{~ (R'2-3), R 3,} R 4, and R ^5, R ³ in the reaction, respectively (R2-1) ~ (R2-3), R 4 and, R ⁵ as synonymous.

[4-4-2. R ³ and R ⁴ are the same]
In the general formula (2), when R ³ and R ⁴ are the same as each other, the diimide derivative (2) can be obtained, for example, by the reaction represented by the reaction formula (R2-4) (hereinafter referred to as reaction (R2-4) May be described) or a method analogous thereto. For convenience, in the reaction formula (R2-4), R ⁴ in the general formula (2) is replaced with R ³ . The method for producing the diimide derivative (2) includes, for example, a reaction (R2-4).

  In the reaction (R2-4), one molar equivalent of the compound represented by the chemical formula (F2) (hereinafter, sometimes referred to as the compound (F2)) and two molar equivalents of the general formula (G2) A compound (primary amine compound) (hereinafter sometimes referred to as compound (G2)) is reacted in the presence of a base to obtain 1 molar equivalent of diimide derivative (2). In the reaction (R2-4), it is preferable to add 2 to 5 mol of the compound (G2) to 1 mol of the compound (F2). When 2 mol or more of the compound (G2) is added to 1 mol of the compound (F2), the yield of the diimide derivative (2) is easily improved. On the other hand, when 5 mol or less of the compound (G2) is added to 1 mol of the compound (F2), the unreacted compound (G2) hardly remains after the reaction (R2-4), and thus the purification of the diimide derivative (2) Becomes easier. The reaction temperature of the reaction (R2-4) is preferably from 80 ° C to 150 ° C. The reaction time of the reaction (R2-4) is preferably from 1 hour to 8 hours. Reaction (R2-4) can be carried out in a solvent. Examples of the solvent include picoline (methylpyridine). The base preferably has low nucleophilicity from the viewpoint of improving the yield of the diimide derivative (2). Such bases include, for example, N, N-diisopropylethylamine (Hünig base).

  The method for producing the diimide derivative (2) may include an appropriate step as necessary. Such a step includes, for example, a purification step. Examples of the purification method include a known method (more specifically, filtration, chromatography, crystallization, or the like).

  When the photoconductor is a single-layer photoconductor, the total content of the quinone derivative (1) and the diimide derivative (2) is 10 parts by mass with respect to 100 parts by mass of the binder resin contained in the single-layer photoconductor. Not less than 200 parts by mass, more preferably not less than 10 parts by mass and not more than 100 parts by mass, particularly preferably not less than 10 parts by mass and not more than 75 parts by mass.

  When the photoconductor is a laminated photoconductor, the total content of the quinone derivative (1) and the diimide derivative (2) is 10 parts by mass or more and 200 parts by mass with respect to 100 parts by mass of the binder resin contained in the charge transport layer. It is preferably at most 20 parts by mass, more preferably at most 20 parts by mass and at most 100 parts by mass.

[4-5. Another electron acceptor compound, electron transport agent]
The charge transport layer may further contain another electron acceptor compound in addition to the quinone derivative (1), the diimide derivative (2), or the quinone derivative (1) and the diimide derivative (2). The single-layer type photosensitive layer may further contain another electron transport agent in addition to the quinone derivative (1), the diimide derivative (2), or the quinone derivative (1) and the diimide derivative (2). Examples of other electron acceptor compounds and electron transporting agents include quinone compounds (quinone compounds other than quinone derivative (1)), diimide compounds (diimide compounds other than diimide derivative (2)), hydrazone compounds, Malononitrile compound, thiopyran compound, trinitrothioxanthone compound, 3,4,5,7-tetranitro-9-fluorenone compound, dinitroanthracene compound, dinitroacridine compound, tetracyanoethylene, 2,4,8- Examples include trinitrothioxanthone, dinitrobenzene, dinitroacridine, succinic anhydride, maleic anhydride, or dibromomaleic anhydride. Examples of the quinone-based compound include a diphenoquinone-based compound, an azoquinone-based compound, an anthraquinone-based compound, a naphthoquinone-based compound, a nitroanthraquinone-based compound, and a dinitroanthraquinone-based compound. One of these electron transporting agents may be used alone, or two or more thereof may be used in combination.

[5. Hole transport agent]
As the hole transporting 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, for example, diamine derivatives (more specifically, benzidine derivatives, N, N, N ', N'-tetraphenylphenylenediamine derivatives, N, N, N' , N′-tetraphenylnaphthylenediamine derivative, N, N, N ′, N′-tetraphenylphenanthrylenediamine derivative, etc.), oxadiazole-based compounds (more specifically, 2,5-di ( 4-methylaminophenyl) -1,3,4-oxadiazole, etc.), styryl compounds (more specifically, 9- (4-diethylaminostyryl) anthracene, etc.), carbazole compounds (more specifically, polyvinyl Carbazole, etc.), organic polysilane compounds, pyrazoline compounds (more specifically, 1-phenyl-3- (p-dimethylaminophenyl) pyrazo Emissions, etc.), hydrazone compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, or triazole compound. One of these hole transporting agents may be used alone, or two or more thereof may be used in combination. Among these hole transporting agents, a compound represented by the general formula (HTM) (benzidine derivative, hereinafter sometimes referred to as hole transporting agent (HTM)) is preferable.

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

In the general formula (HTM), Q ⁸ , Q ¹⁰ , Q ¹¹ , Q ¹² , Q ¹³ , and Q ¹⁴ each preferably independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, It preferably represents a hydrogen atom, a methyl group, or an ethyl group. Preferably, k represents 0. b and c preferably represent 0.

  As the hole transporting agent (HTM), for example, a hole transporting agent represented by the chemical formula (HTM1) (hereinafter sometimes referred to as a hole transporting agent (HTM1)) may be mentioned.

  When the photoconductor is a single-layer photoconductor, the content of the hole transporting 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 preferably 10 parts by mass or more and 100 parts by mass or less, particularly preferably 10 parts by mass or more and 75 parts by mass or less.

  When the photoreceptor is a laminated photoreceptor, the content of the hole transporting 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 transporting layer. It is more preferable that the amount be 20 parts by mass or more and 100 parts by mass or less.

[6. Charge generating agent]
When the photoconductor is a laminated photoconductor, the charge generating layer may contain a charge generating agent. When the photoreceptor is a single-layer type photoreceptor, the single-layer type photoreceptor may contain a charge generating agent.

  The charge generator is not particularly limited as long as it is a charge generator for a photoreceptor. As the charge generator, for example, phthalocyanine pigments, perylene pigments, bisazo pigments, trisazo pigments, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, indigo pigments, azurenium pigments, cyanine Pigment, powder of an inorganic photoconductive material (more specifically, selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, amorphous silicon, or the like), pyrylium pigment, ansanceron-based pigment, triphenylmethane-based pigment, sulene-based pigment Pigment, toluidine pigment, pyrazoline pigment, or quinacridone pigment. One kind of the charge generating agent may be used alone, or two or more kinds may be used in combination.

  Examples of the phthalocyanine-based pigment include titanyl phthalocyanine represented by the chemical formula (CGM-1) (hereinafter sometimes referred to as a charge generating agent (CGM-1)) or metal phthalocyanine. Examples of the metal phthalocyanine include a metal-free phthalocyanine represented by the chemical formula (CGM-2) (hereinafter, sometimes referred to as a charge generator (CGM-2)), hydroxygallium phthalocyanine, or chlorogallium phthalocyanine. The phthalocyanine-based pigment may be crystalline or non-crystalline. The crystal shape (for example, X type, α type, β type, Y type, V type, or II type) of the phthalocyanine pigment is not particularly limited, and phthalocyanine pigments having various crystal shapes are used.

  Examples of the crystal of the metal-free phthalocyanine include an X-type crystal of the metal-free phthalocyanine (hereinafter, sometimes referred to as an X-type metal-free phthalocyanine). Examples of the crystal of titanyl phthalocyanine include, for example, α-type, β-type, or Y-type crystal of titanyl phthalocyanine (hereinafter, may be referred to as α-type titanyl phthalocyanine, β-type titanyl phthalocyanine, and Y-type titanyl phthalocyanine, respectively). Can be Examples of the hydroxygallium phthalocyanine crystal include a hydroxygallium phthalocyanine V-type crystal. Examples of chlorogallium phthalocyanine crystals include chlorogallium phthalocyanine type II crystals.

  For example, in a digital optical image forming apparatus (for example, a laser beam printer or a facsimile using a light source such as a semiconductor laser), it is preferable to use a photoconductor having sensitivity in a wavelength region of 700 nm or more. Since it has a high quantum yield in a wavelength region of 700 nm or more, the charge generator is preferably a phthalocyanine pigment, and more preferably a metal-free phthalocyanine or titanyl phthalocyanine. When the photosensitive layer contains at least one selected from the group consisting of a quinone derivative (1) and a diimide derivative (2), in order to particularly improve the electrical characteristics of the photosensitive member, an X-type charge generating agent is used. Metal-free phthalocyanine or Y-type titanyl phthalocyanine is more preferable, and Y-type titanyl phthalocyanine is particularly preferable.

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

(Method of measuring CuKα characteristic X-ray diffraction spectrum)
An example of a method for measuring a 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), and an X-ray tube Cu, a tube voltage of 40 kV, a tube current of 30 mA, and CuKα are used. An X-ray diffraction spectrum is measured under the condition of a characteristic X-ray wavelength of 1.542 °. The measurement range (2θ) is, for example, not less than 3 ° and not more than 40 ° (start angle 3 °, stop angle 40 °), and the scanning speed is, for example, 10 ° / min.

  In a photoreceptor applied to an image forming apparatus using a short-wavelength laser light source, an ensenzlon-based pigment is suitably used as a charge generating agent. The wavelength of the short wavelength laser light is, for example, 350 nm or more and 550 nm or less.

  When the photoreceptor is a single-layer type photoreceptor, the content of the charge generator is 0.1 parts by mass or more and 50 parts by mass or less based on 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 photoconductor is a laminated photoconductor, 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 generating layer. It is more preferable that the amount be from not less than 500 parts by mass to not more than 500 parts by mass.

[7. Binder resin]
Examples of the binder resin include a thermoplastic resin, a thermosetting resin, and a photocurable resin. As the thermoplastic resin, for example, a polycarbonate resin, a polyarylate resin, a styrene-butadiene resin, a styrene-acrylonitrile resin, a styrene-maleic acid resin, an acrylic resin, a styrene-acrylic resin, a polyethylene resin, an 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 Polyether resins are mentioned. Examples of the thermosetting resin include a silicone resin, an epoxy resin, a phenol resin, a urea resin, and a melamine resin. As the photocurable resin, for example, an epoxy-acrylic acid-based resin (more specifically, an acrylic acid derivative adduct of an epoxy compound or the like) or a urethane-acrylic acid resin (an acrylic acid derivative adduct of a urethane compound) is used. No. One of these binder resins may be used alone, or two or more thereof may be used in combination.

  Among these resins, a polycarbonate resin or a polyarylate resin is preferable because a single-layer photosensitive layer and a charge transporting layer having an excellent balance of processability, mechanical strength, optical characteristics, and abrasion resistance can be obtained. Furthermore, from the viewpoint that the compatibility with the quinone derivative (1) and the diimide derivative (2) is good and the dispersibility of the quinone derivative (1) and the diimide derivative (2) in the photosensitive layer is improved, the general formula (3) ) Or a polyarylate resin having a repeating unit represented by the general formula (4) (hereinafter sometimes referred to as a polycarbonate resin (3)). 4)) is more preferable.

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 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 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 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 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 or different from each other. R ¹⁷ and R ¹⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms which may have a halogen atom. R ¹⁷ and R ¹⁸ may be the same or different from each other.

In 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 preferable. 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 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. It is preferable to represent More preferably, R ¹¹ and R ¹² represent a hydrogen atom or a methyl group, or a cyclohexylidene group formed by bonding to each other.

In the 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, and is a methyl group or A methyl fluoride group is more preferred, and a methyl group or a trifluoromethyl group is even more preferred. In the general formula (3), R ¹³ and R ¹⁴ preferably represent a hydrogen atom or a methyl group optionally having a halogen atom, more preferably represent a hydrogen atom or a methyl fluoride group, and represent a hydrogen atom or More preferably, it represents a trifluoromethyl group. R ¹³ and R ¹⁴ are preferably the same as each other. From the viewpoint of further improving the filming resistance of the photoconductor, it is preferable that at least one of R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ in Formula (3) has one or more halogen atoms. .

  As the polycarbonate resin (3), for example, a repeating unit represented by the chemical formula (PC-1), the chemical formula (PC-2), the chemical formula (PC-3), the chemical formula (PC-4), or the chemical formula (PC-5) And a polycarbonate resin having a unit (hereinafter may be referred to as polycarbonate resins (PC-1) to (PC-5), respectively).

In the 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 preferable. 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, more preferably a hydrogen atom or a methyl group. Preferably, R ¹⁵ and R ¹⁶ are different from each other. R ¹⁷ and R ¹⁸ preferably represent an alkyl group having 1 to 3 carbon atoms, more preferably 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, in the general formula (4), at least one of R ¹⁵ , R ¹⁶ , R ¹⁷ , and R ¹⁸ preferably has one or more halogen atoms. . The substitution positions of two carbonyl groups are in an ortho position (o position), a meta position (m position), or a para position (p position) on a benzene ring having two carbonyl groups.

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

  The viscosity average molecular weight of the binder resin is preferably 40,000 or more, more preferably 40,000 or more and 51,000 or less. When the viscosity average molecular weight of the binder resin is 40,000 or more, the abrasion resistance of the photoconductor is easily improved. When the viscosity average molecular weight of the binder resin is 51,000 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 the single layer type photosensitive layer coating solution increases. Not just. 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. Examples of the resin of the resin particles include a silicone resin, a polyphenylene sulfide resin (hereinafter sometimes referred to as a PFS resin), and a polytetrafluoroethylene resin (hereinafter sometimes referred to as a PTFE resin). . The resin particles preferably contain a halogen atom (more specifically, a fluorine atom or the like). It is preferable that the filler particles have no 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. The volume median diameter D50 of the filler particles is measured using a precision particle size distribution measuring device (“Beckman Coulter Co., Ltd.,“ Coulter Counter Multitizer 3 ”). The volume median diameter D ₅₀ means a median diameter calculated on a volume basis using the Coulter counter method.

  The content of the filler particles is preferably 0.5 part by mass or more and 30 parts by mass or less based on 100 parts by mass of the binder resin in the single-layer type photosensitive layer or the charge transport layer.

[9. Base resin]
When the photoconductor is a laminated photoconductor, 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 photoconductor. Examples of the base resin include a thermoplastic resin, a thermosetting resin, and a photocurable resin. As the thermoplastic resin, for example, 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 exemplified. Examples of the thermosetting resin include a silicone resin, an epoxy resin, a phenol resin, a urea resin, a melamine resin, and other crosslinkable thermosetting resins. As the photocurable resin, for example, an epoxy-acrylic acid-based resin (more specifically, an adduct of an acrylic acid derivative of an epoxy compound) or a urethane-acrylic acid-based resin (more specifically, an acrylic resin of a urethane compound) Acid derivative adduct). One type of base resin may be used alone, or two or more types may be used in combination.

  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 coating solution for the charge transport layer. In the production of a laminated photoreceptor, it is general that a charge generation layer is formed on a conductive substrate, and a charge transport layer is formed on the charge generation layer. This is because when forming the charge transport layer, the charge transport layer coating liquid is applied on 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, Examples include dispersion stabilizers, waxes, donors, surfactants, plasticizers, sensitizers, or leveling agents.

[11. Middle layer]
The intermediate layer (undercoat layer) contains, for example, inorganic particles and a resin (a resin for the intermediate layer). It is considered that the presence of the intermediate layer smoothes the flow of current generated when the photosensitive member is exposed and suppresses a rise in resistance while maintaining an insulating state that can suppress the occurrence of leakage.

  As the inorganic particles, for example, particles of a metal (more specifically, aluminum, iron, copper, or the like), a metal oxide (more specifically, titanium oxide, alumina, zirconium oxide, tin oxide, or zinc oxide) And the like, or particles of a non-metal oxide (more specifically, silica and the like). One type of these inorganic particles may be used alone, or two or more types may be used in combination.

  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 additives are the same as those of the photosensitive layer.

[12. Production method of photoreceptor]
Next, when the photoreceptor is a single-layer type photoreceptor, the single-layer type photoreceptor is manufactured by, for example, applying a coating solution for a single-layer type photosensitive layer on a conductive substrate and drying. The coating solution for a single-layer photosensitive layer includes, for example, a charge generating agent, a hole transporting agent, and at least one selected from the group consisting of a quinone derivative (1) and a diimide derivative (2) as an electron transporting agent. It is prepared by dissolving or dispersing, in a solvent, a binder resin, filler particles, and additives added as necessary.

  When the photoconductor is a stacked photoconductor, the stacked photoconductor is manufactured, for example, as follows. First, a coating solution for the charge generation layer and a coating solution for the charge transport layer are prepared. A charge generation layer is formed by applying the coating solution for a charge generation layer on a conductive substrate and drying. Subsequently, a charge transport layer coating solution is applied on the charge generation layer and dried to form a charge transport layer. As a result, a laminated photoconductor is manufactured.

  The coating liquid for a charge generation layer 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 charge transport layer coating solution includes a hole transport agent, at least one selected from the group consisting of a quinone derivative (1) and a diimide derivative (2) as an electron acceptor compound, a binder resin, and filler particles. It is prepared by dissolving or dispersing an additive added as necessary in a solvent.

  The solvent contained in the coating solution for the charge generation layer, the coating solution for the charge transport layer, or the coating solution for the single-layer photosensitive layer (hereinafter sometimes referred to as the coating solution) dissolves each component contained in the coating solution. Or, it is not particularly limited as long as it can be dispersed. Examples of the solvent include alcohols (more specifically, methanol, ethanol, isopropanol, or butanol, etc.), aliphatic hydrocarbons (more specifically, n-hexane, octane, or cyclohexane, etc.), and aromatic hydrocarbons. Hydrogen (more specifically, benzene, toluene, or xylene, etc.), halogenated hydrocarbon (more specifically, dichloromethane, dichloroethane, carbon tetrachloride, or chlorobenzene, etc.), ether (more specifically, dimethyl ether) , Diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, etc.), ketones (more specifically, acetone, methyl ethyl ketone, cyclohexanone, etc.), esters (more components) 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 photoconductor, it is preferable to use a non-halogen solvent (a solvent other than a halogenated hydrocarbon) as the solvent.

  The coating liquid is prepared by mixing the components and dispersing the components in a solvent. For mixing or dispersion, 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 liquid is not particularly limited as long as the method can uniformly apply the coating liquid on 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 liquid is not particularly limited as long as the solvent in the coating liquid can be evaporated. For example, a method of performing heat treatment (hot-air drying) using a high-temperature dryer or a reduced-pressure dryer is exemplified. The heat treatment conditions are, for example, a temperature of 40 ° C. or more and 150 ° C. or less, and a time of 3 minutes or more and 120 minutes or less.

  The method for manufacturing the photoconductor may further include, if necessary, one or both of a step of forming an intermediate layer and a step of forming a protective layer. In the step of forming the intermediate layer and the step of forming the protective layer, a known method is appropriately selected.

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

<Second Embodiment: Image Forming Apparatus>
The second embodiment relates to an image forming apparatus. Hereinafter, one mode 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 the image forming apparatus according to the second embodiment. The image forming apparatus 100 according to the second embodiment includes an image forming unit 40. The image forming unit 40 includes the image carrier 30, a charging unit 42, an exposing 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 section 42 charges the surface of the image carrier 30. The charging polarity of the charging unit 42 is positive. The exposure section 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 P 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 due to filming and 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 photoreceptor according to the first embodiment has excellent filming resistance and can suppress the occurrence of transfer memory. Therefore, the image forming apparatus 100 according to the second embodiment can suppress image defects due to filming and transfer memory. Hereinafter, suppression of transfer memory generation will be described in detail.

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

  An image in which an image defect has occurred will be described with reference to FIG. FIG. 4 is a diagram illustrating an image 60 in which an image ghost has occurred. Image 60 includes region 62 and region 64. The area 62 is an area corresponding to one rotation of the image carrier, and the area 64 is also an area corresponding to one rotation of the image carrier. Region 62 includes image 66. The image 66 is composed of a donut-shaped solid image. The area 64 includes an image 68 and an image 69. 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 is darker than the design image density. Note that the image of the region 64 is composed of a halftone image on the entire surface of the design image.

  The photoreceptor according to the first embodiment tends to suppress the occurrence of image defects caused by 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 occurrence of an image defect due to the transfer memory can be suppressed.

  Hereinafter, each part will be described in detail. An image forming apparatus 100 according to the second embodiment will be described with reference to FIG. The image forming apparatus 100 is not particularly limited as long as it is an electrophotographic image forming apparatus. The image forming apparatus 100 may be, for example, a monochrome image forming apparatus or a color image forming apparatus. When the image forming apparatus 100 is a color image forming apparatus, the image forming apparatus 100 employs, for example, a tandem method. Hereinafter, the tandem type 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 adopting the direct transfer method, the image carrier 30 is easily affected by a transfer bias, so that a transfer memory is usually easily generated. Further, in an image forming apparatus employing the direct transfer method, since the surface of the image carrier 30 may come into contact with the recording medium P, minute components easily adhere to the surface of the image carrier 30, and filming is difficult. , 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 photoreceptor according to the first embodiment has excellent filming resistance and can suppress the occurrence of transfer memory. Therefore, when the photoconductor according to the first embodiment is provided as the image carrier 30, even when the image forming apparatus 100 employs 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, each of the image forming units 40a, 40b, 40c, and 40d will be referred to as an image forming unit 40 unless it is necessary to distinguish them.

  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 a central position of the image forming unit 40. The image carrier 30 is provided rotatably 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 this order from the upstream side in the rotation direction of the image carrier 30 with respect to the charging unit 42. Can be Note that the image forming unit 40 may further include a charge removing unit (not shown).

  By each of the image forming units 40a to 40d, toner images of a plurality of colors (for example, four colors of black, cyan, magenta, and yellow) are sequentially superimposed on the recording medium P on the transfer belt 50. When the image forming apparatus 100 is a monochrome image forming apparatus, the image forming apparatus 100 includes the image forming unit 40a, and the image forming units 40b to 40d are omitted.

  The charging unit 42 is a charging roller. The charging roller charges the surface of the image carrier 30 while contacting the surface of the image carrier 30. Generally, in an image forming apparatus provided with a charging roller, an image defect easily occurs due to filming and transfer memory. However, the photoconductor according to the first embodiment is provided in the image forming apparatus 100 as the image carrier 30. The photoreceptor according to the first embodiment has excellent filming resistance and can suppress the occurrence of transfer memory. Therefore, even when a charging roller is provided as the charging unit 42 in the image forming apparatus 100, occurrence of image defects due to filming and transfer memory is suppressed. An example of another contact charging type charging unit is a charging brush. The charging unit 42 may be of a non-contact type. Examples of the non-contact charging section include a corotron charging section and a scorotron charging section.

  The voltage applied by the charging unit 42 is not particularly limited. Examples of the voltage applied by the charging unit 42 include a DC voltage, an AC voltage, and 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 the DC voltage, the voltage 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. When the charging unit 42 applies only the 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 to light. Thus, an electrostatic latent image is formed on the surface of the image carrier 30. The electrostatic latent image is formed based on the 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. Normally, when the developer contains a 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, minute components adhere to the surface of the photoconductor, 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 photoreceptor according to the first embodiment has excellent filming resistance. For this reason, the image forming apparatus 100 according to the second embodiment can suppress an image defect due to filming even when the developer contains a 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 so as 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. The transfer unit 48 includes, for example, a transfer roller.

  The fixing unit 54 heats and / or presses 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. By heating and / or pressurizing the toner image, the toner image is fixed on the recording medium P. 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 includes the photoconductor according to the first embodiment as an image carrier, so that occurrence of an image defect can be suppressed.

<Third embodiment: process cartridge>
The third embodiment relates to a process cartridge. The process cartridge according to the third embodiment includes the photoconductor 1 according to the first embodiment. Subsequently, a process cartridge according to the third embodiment will be described with reference to FIG.

  The process cartridge includes a unitized image carrier. The process cartridge adopts a configuration in which at least one selected from the group consisting of a charging unit 42, an exposure unit 44, a developing unit 46, a transfer unit 48, and a cleaning unit 52 is unitized in addition to the image carrier 30. You. The process cartridge corresponds to, for example, each of the image forming units 40a to 40d. 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 characteristic or the like of the image carrier 30 is deteriorated, the entire 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 the occurrence of filming and transfer memory.

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

<1. Photoconductor Materials>
The following electron transporting agent, hole transporting agent, charge generating agent, binder resin, and filler particles were prepared as materials for forming the single-layered photosensitive layer of the single-layered photoconductor.

[1-1. Electron transport agent]
As electron transport agents, quinone derivatives (1-1) to (1-4) and (1-6) were prepared. The quinone derivatives (1-1) to (1-4) and (1-6) were produced by the following methods, respectively.

[1-1-1. Production of quinone derivative (1-1)]
According to the reaction represented by the reaction formula (r1-1) and the reaction formula (r1-2) (hereinafter, sometimes referred to as the reaction (r1-1) and (r1-2), respectively), the quinone derivative (1- 1) was manufactured.

  In the reaction (r1-1), the naphthol derivative (A1-1) (1-naphthol) and the alcohol derivative (B1-1) were reacted to obtain an intermediate naphthol derivative (C1-1). Specifically, 1.44 g (0.010 mol) of the naphthol derivative (A1-1), 1.57 g (0.010 mol) of the alcohol derivative (B1-1), and 30 mL of acetic acid were put into a flask, and the acetic acid solution was added. Was prepared. 0.98 g (0.010 mol) of concentrated sulfuric acid was added dropwise to the contents of the flask, and the mixture was stirred at room temperature for 8 hours. Ion exchange water and chloroform were added to the contents of the flask to obtain an organic layer. The organic layer was washed with an aqueous sodium hydroxide solution and neutralized. Subsequently, anhydrous sodium sulfate was added to the organic layer, and the organic layer was dried. The dried organic layer was distilled off under reduced pressure to obtain a crude product containing a naphthol derivative (C1-1).

  In the reaction (r1-2), the naphthol derivative (C1-1) was oxidized to obtain a quinone derivative (1-1). Specifically, a crude product containing a naphthol derivative (C1-1) and 100 mL of chloroform were charged into a flask to prepare a chloroform solution. 2.46 g (0.010 mol) of chloranil was added to the contents of the flask, and the mixture was stirred at room temperature for 8 hours. Subsequently, the contents of the flask were filtered to obtain a filtrate. The solvent of the obtained filtrate was distilled off to obtain a residue. The residue obtained was purified by silica gel column chromatography using chloroform as a developing solvent. As a result, a quinone derivative (1-1) was obtained. The yield of the quinone derivative (1-1) was 1.68 g, and the yield of the quinone derivative (1-1) from the naphthol derivative (A1-1) was 60 mol%.

[1-1-2. Production of quinone derivatives (1-2) to (1-4) and (1-6)]
The quinone derivatives (1-2) to (1-4) and (1-6) were produced in the same manner as in the production of the quinone derivative (1-1), except for the following changes. In the production of the quinone derivatives (1-2) to (1-4) and (1-6), each raw material was added in the same mole number as the corresponding raw material in the production of the quinone derivative (1-1). did.

  Table 1 shows the naphthol derivative (A1), alcohol derivative (B1), and naphthol derivative (C1) in the reaction (r1-1). In Table 1, A1-1 in the naphthol derivative (A1) column indicates the naphthol derivative (A1-1). B1-1 to B1-4 and B1-6 in the alcohol derivative (B) column indicate the alcohol derivatives (B1-1) to (B1-4) and (B1-6), respectively. C1-1 to C1-4 and C1-6 in the naphthol derivative (C) column represent the naphthol derivatives (C1-1) to (C1-4) and (C1-6), respectively.

  The alcohol derivative (B1-1) used in the reaction (r1-1) was changed to any of the alcohol derivatives (B1-2) to (B1-4) and (B1-6). As a result, in the reaction (r1-1), crude products containing the naphthol derivatives (C1-2) to (C1-4) and (C1-6) instead of the naphthol derivative (C1-1) are obtained. Was done.

  Table 1 shows the naphthol derivative (C1) and the quinone derivative (1) in the reaction (r1-2). In Table 1, 1-1 to 1-4 and 1-6 in the quinone derivative (1) column represent the quinone derivatives (1-1) to (1-4) and (1-6), respectively. The crude product containing the naphthol derivative (C1-1) used in the reaction (r1-2) is converted into a crude product containing any of the naphthol derivatives (C1-2) to (C1-4) and (C1-6). changed. As a result, in the reaction (r1-2), quinone derivatives (1-2) to (1-4) and (1-6) were obtained instead of the quinone derivative (1-1).

  Table 1 shows the yield and yield of the quinone derivative (1). In Table 1, the alcohol derivatives (B1-2) to (B1-4) and (B1-6) are represented by the following chemical formulas (B1-2) to (B1-4) and (B1-6), respectively. You. The naphthol derivatives (C1-2) to (C1-4) and (C1-6) are represented by the following chemical formulas (C1-2) to (C1-4) and (C1-6), respectively.

  Diimide derivatives (2-1) to (2-4) and (2-6) were prepared. The diimide derivatives (2-1) to (2-4) and (2-6) were produced by the following methods, respectively.

[1-1-3. Production of diimide derivative (2-1)]
A diimide derivative (2-1) was produced according to a reaction represented by a reaction formula (r2-4) (hereinafter, sometimes referred to as reaction (r2-4)).

  In the reaction (r2-4), the compound (F2-1) (naphthalene-1,4,5,8-tetracarboxylic dianhydride) 2.68 g (10 mmol) was represented by the chemical formula (G2-1). 4.64 g (20 mmol) of the compound and 50 mL of picoline were charged into a flask to prepare a picoline solution. The temperature of the contents of the flask was raised to 100 ° C. and maintained at 100 ° C., and the contents of the flask were stirred for 4 hours. After the reaction, ion-exchanged water was charged into the flask and extracted with chloroform. The solvent (picoline) in the organic layer was removed to obtain a residue. The obtained residue was purified by silica gel column chromatography using chloroform as a developing solvent. As a result, a diimide derivative (2-1) was obtained. The yield of the diimide derivative (2-1) was 4.16 g, and the yield of the diimide derivative (2-1) from the compound (F2-1) in the reaction (r2-4) was 60 mol%.

[1-1-4. Production of diimide derivative (2-5)]
Except having changed the following point, the diimide derivative (2-5) was manufactured by the method similar to manufacture of the diimide derivative (2-1). In addition, each raw material used in the production of the diimide derivative (2-5) was added in the same mole number as the corresponding raw material in the production of the diimide derivative (2-1).

  In the production of the diimide derivative (2-5), the compound (G2-1) used in the reaction (r2-4) was changed to a compound (G2-5). As a result, a diimide derivative (2-5) was obtained instead of the diimide derivative (2-1). Table 2 shows the compound (F2), the compound (G2), and the diimide derivative (2) in the reaction (r2-4). In Table 2, F2-1 represents the compound (F2-1). G2-1 represents the compound (G2-1), and G2-5 represents the compound (G2-5).

  Table 2 shows the yield and yield of the diimide derivative (2). Note that the compound (G2-5) is represented by a chemical formula (G2-5).

[1-1-5. Production of diimide derivative (2-2)]
Reactions represented by the reaction formulas (r'2-1), (r'2-2) and (r'2-3) (hereinafter referred to as reaction (r'2-1) and reaction (r'2-2, respectively) ) And reaction (sometimes described as r′2-3)) to produce a diimide derivative (2-2).

  In the reaction (r′2-1), 3.42 g (10 mmol) of the compound (A2-2), 1.35 g (10 mmol) of the compound (E2-2), and 1.3 g of N, N-diisopropylethylamine ( 10 mmol) and 50 mL of dioxane were charged into a flask to prepare a dioxane solution. The temperature of the contents of the flask was increased to 100 ° C. and maintained at 100 ° C., and the contents of the flask were stirred for 2 hours. After the reaction, dioxane was removed to obtain a residue. The residue obtained was purified by silica gel column chromatography using ethyl acetate / hexane (volume ratio V / V = 1/2) as a developing solvent. As a result, an intermediate product represented by the chemical formula (C′2-2) (hereinafter, sometimes referred to as compound (C′2-2)) was obtained.

  In the reaction (r'2-2), the compound (C'2-2) and 15 mL of trifluoroacetic acid were charged into a flask to prepare a trifluoroacetic acid solution. As the compound (C'2-2), the entire amount obtained in the reaction (r'2-1) was used in the reaction (r'2-2). The temperature of the contents of the flask was raised to 80 ° C. and maintained at 80 ° C., and the contents of the flask were stirred for 24 hours. After the reaction, trifluoroacetic acid was removed to obtain a residue. The residue obtained was purified by silica gel column chromatography using ethyl acetate / hexane (volume ratio V / V = 1/4) as a developing solvent. Thus, an intermediate product represented by the chemical formula (D'2-2) (hereinafter, sometimes referred to as compound (D'2-2)) was obtained.

  In the reaction (r'2-3), the compound (D'2-2), 2.32 g (10 mmol) of the compound represented by the chemical formula (B2-2), and 1.3 g of N, N-diisopropylethylamine ( 10 mmol) and 50 mL of dioxane were charged into a flask to prepare a dioxane solution. The temperature of the contents of the flask was increased to 100 ° C. and maintained at 100 ° C., and the contents of the flask were stirred for 2 hours. After the reaction, dioxane was removed to obtain a residue. The residue obtained was purified by silica gel column chromatography using ethyl acetate as a developing solvent. As a result, a diimide derivative (2-2) was obtained. The yield of the diimide derivative (2-2) was 2.69 g, and the yield of the diimide derivative (2-2) from the compound (A2-2) in the reactions (r′2-1) to (r′2-3) was determined. The rate was 45 mol%.

[1-1-6. Production of diimide derivatives (2-3) and (2-6)]
The diimide derivatives (2-3) and (1-6) were produced in the same manner as in the production of the diimide derivative (2-2), except for the following changes. In addition, each raw material used in the synthesis of the diimide derivative (2-3) and (2-6) was added in the same mole number as the corresponding raw material in the production of the diimide derivative (2-2).

  In the production of diimide derivatives (2-3) and (2-6), compound (B2-2) used in reaction (r′2-3) was changed to compounds (B2-3) and (B2-6), respectively. did. As a result, diimide derivatives (2-3) and (2-6) were obtained instead of diimide derivative (2-2). Table 3 shows compound (A2), compound (D'2), compound (B2), and diimide derivative (2) in reactions (r'2-1) to (r'2-3).

  Table 3 shows the yield and yield of the diimide derivative (2). The compounds (B2-3) and (B2-6) are represented by the following chemical formulas (B2-3) and (B2-6), respectively.

Next, using a proton nuclear magnetic resonance spectrometer (manufactured by JASCO Corporation, 300 MHz), the manufactured quinone derivatives (1-1) to (1-4) and (1-6) and the diimide derivative (2-1) ) To (2-3) and (2-5) to (2-6) ¹ H-NMR spectra were measured. CDCl ₃ was used as a solvent. Tetramethylsilane (TMS) was used as an internal standard sample. Among these, the quinone derivative (1-1) and the diimide derivative (2-1) are mentioned as typical examples. FIGS. 5 and 6 show ¹ H-NMR spectra of the quinone derivative (1-1) and the diimide derivative (2-1), respectively. 5 and 6, the vertical axis indicates signal intensity (unit: arbitrary unit), and the horizontal axis indicates chemical shift (unit: ppm). The chemical shift values of the quinone derivative (1-1) and the diimide derivative (2-1) are shown below.
Quinone derivative (1-1): ¹ H-NMR (300 MHz, CDCl ₃ ) δ = 8.30 (d, 2H), 7.18-7.74 (m, 16H), 4.57 (q, 2H) , 1.50 (d, 6H).
Diimide derivative (2-1): ¹ H-NMR (300 MHz, CDCl ₃ ) δ = 8.70 (d, 4H), 7.62-7.75 (m, 8H), 7.36-7.55 ( m, 8H).

^{From the 1} H-NMR spectrum and the chemical shift value, it was confirmed that the quinone derivative (1-1) and the diimide derivative (2-1) were obtained. The same applies to other quinone derivatives (1-2) to (1-4) and (1-6) and diimide derivatives (2-2) to (2-3) and (2-5) to (2-6). a manner, by ¹ H-NMR spectrum and chemical shift values, respectively quinone derivative (1-2) to (1-4) and (1-6), and diimide derivative (2-2) to (2-3) and It was confirmed that (2-5) to (2-6) were obtained.

[1-1-7. Preparation of Compounds (ET-1) to (ET-3)]
Compounds represented by chemical formulas (ET-1) to (ET-4) (hereinafter sometimes referred to as compounds (ET-1) to (ET-4), respectively) were prepared as electron transporting agents.

[1-2. Hole transport agent]
The hole transporting agent (HTM1) described in the first embodiment was prepared as the hole transporting agent.

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

  The charge generator (CGM-2) was a metal-free phthalocyanine (X-type metal-free phthalocyanine) represented by the chemical formula (CGM-2). Further, the crystal structure of the charge generating agent (CGM-2) was X type.

[1-4. Binder resin]
As the binder resin, the polycarbonate resins (PC-1) to (PC-5) described in the first embodiment (the viscosity average molecular weights are 40,000, 45,500, 51,000, 48,500 and 49,000, respectively) And a polyarylate resin (PAR-1) (viscosity average molecular weight 50,000).

[1-5. Filler particles]
Table 4 shows filler particles used in Examples and Comparative Examples. Table 4 shows the type, material, volume median diameter, trade name, and manufacturer of the filler particles. Note that “AEROSIL” and “Trepearl” in the column “Product Name” in Table 4 are registered trademarks. In Table 4, the volume median diameter D ₅₀ of the filler particles was measured using a precision particle size distribution measuring device described in the first embodiment.

<2. Production of single-layer photoconductor>
Photoconductors (A-1) to (A-28) and Photoconductors (B-1) to (B-6) were manufactured using the material for forming the photosensitive layer.

[2-1. Production of Photoconductor (A-1)]
3 parts by mass of a charge generating agent (CGM-1), 60 parts by mass of a compound (HTM1) as a hole transporting agent, 40 parts by mass of a quinone derivative (1-1) as an electron transporting agent, 5 parts by mass of filler particles F7, 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 charged into a container. Using a rod-shaped acoustic oscillator, the material in the container and the solvent were mixed for 2 minutes, 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. Thus, a coating solution for a single-layer photosensitive layer was obtained. The coating solution for a single-layer type photosensitive layer was applied on an aluminum drum-shaped support as a conductive substrate by a dip coating method. The applied coating solution for a single-layer type photosensitive layer was dried with hot air at 100 ° C. for 40 minutes. Thus, a single-layer type photosensitive layer (25 μm in thickness) was formed on the conductive substrate. As a result, a single-layer type photoreceptor (A-1) was obtained.

[2-2. Production of Photoconductors (A-2) to (A-28) and Photoconductors (B-1) to (B-6)]
Except for the following changes, the photoconductors (A-2) to (A-28) and the photoconductors (B-1) to (B-6) are manufactured in the same manner as in the production of the photoconductor (A-1). ) Were each manufactured. The charge generator (CGM-1) used in the production of the photoconductor (A-1) was changed to a charge generator of the type shown in Tables 5 to 7. 40 parts by mass of the quinone derivative (1-1) as the electron transporting agent used in the production of the photoreceptor (A-1) were changed to the types and contents of the electron transporting agents shown in Tables 5 to 7. The filler particles F7 used in the production of the photoconductor (A-1): 5 parts by mass were changed to the types and contents of the types of filler particles shown in Tables 5 to 7. The polycarbonate resin (PC-1) as the binder resin used in the production of the photoreceptor (A-1) was changed to the types of binder resins shown in Tables 5 to 7. Tables 5 to 7 show the configurations of the photoconductors (A-1) to (A-28) and the photoconductors (B-1) to (B-6). In Tables 5 to 7, CGM, HTM, and ETM indicate a charge generating agent, a hole transporting agent, and an electron transporting agent, respectively. In Tables 5 to 7, CGM-1 and CGM-2 in the CGM column denote Y-type titanyl phthalocyanine (charge generator (CGM-1)) and X-type metal-free phthalocyanine (charge generator (CGM-2)), respectively. Show. H-1 in the HTM column indicates a compound (HTM1). 1-1 to 1-4 and 1-6, 2-1 to 2-3 and 2-5 to 2-6 in the ETM column, and ET-1 to ET-3 are quinone derivatives (1-1) to -1, respectively. (1-4) and (1-6), diimide derivatives (2-1) to (2-3) and (2-5) to (2-6), and compounds (ET-1) to (ET-3) ). In Tables 5 to 7, F1, F3 to F4, F6 to F7, and F9 to F11 in the type column of the filler particles indicate the filler particles F1, F3 to F4, F6 to F7, and F9 to F11, respectively. In Tables 5 to 7, PC-1 to PC-5 and PAR-1 in the column of binder type are polycarbonate resins (PC-1) to (PC-5) and polyarylate resin (PAR-1), respectively. Is shown.

<3. Evaluation of photoconductor>
[3-1. Evaluation of sensitivity characteristics of single-layer type photoreceptor]
The electrical characteristics (sensitivity characteristics) of each of the manufactured single-layer photoconductors (A-1) to (A-28) and single-layer photoconductors (B-1) to (B-6) were evaluated. . The evaluation of the electrical characteristics was performed in an environment at a temperature of 23 ° C. and a relative humidity of 50% RH.

The surface of the single-layer type photoconductor was charged to a positive polarity using a drum sensitivity tester (manufactured by Gentec Corporation). The charging condition was set at a rotation speed of the single-layer photoreceptor of 31 rpm. The surface potential of the single-layer type photosensitive member immediately after charging was set to + 600V. Next, monochromatic light (wavelength 780 nm, half width 20 nm, light energy 1.5 μJ / cm ² ) was extracted from the white light of the halogen lamp using a band-pass filter. The extracted monochromatic light was applied to the surface of the single-layer type photoreceptor. The surface potential of the single-layer type photoreceptor was measured 0.5 seconds after the irradiation was completed. The measured surface potential was defined as a sensitivity potential ( _VL , unit V). Tables 8 and 9 show the measured sensitivity potentials (V _L ) of the single-layer type photoreceptor. The smaller the absolute value of the sensitivity potential (V _L ), the better the sensitivity characteristics of the single-layer type photoreceptor.

[3-2. Evaluation of image defect (image ghost)]
Image defects (image ghost) were evaluated for each of the single-layer photoconductors (A-1) to (A-28) and the single-layer photoconductors (B-1) to (B-6). Evaluation of image defects was performed in an environment at a temperature of 10 ° C. and a relative humidity of 20% RH.

  The single-layer type photoreceptor was mounted on an evaluation machine. The evaluation machine used was an image forming apparatus ("FS-C5250DN" modified machine manufactured by Kyocera Document Solutions Inc.). A polymerized toner (a one-component developer of "prototype" manufactured by Kyocera Document Solutions Inc.) was charged into the developing section of the evaluation machine. This evaluation machine employs a contact charging system and a direct transfer system. This evaluation machine was provided with a charging roller as a charging unit of a contact charging system and a cleaning blade as a cleaning unit. "Kyocera Document Solutions brand paper VM-A4" (A4 size) sold by Kyocera Document Solutions Inc. was used as a recording medium.

  First, 1,000 print patterns (image density 40%) were printed on a recording medium (A4 size paper) at intervals of 15 seconds, and a print test was performed. Thereafter, an image for evaluation was created by the following operation.

  The evaluation image will be described with reference to FIG. FIG. 7 is a diagram showing an evaluation image 70. The evaluation image 70 includes a region 72 and a region 74. The area 72 is an area corresponding to one rotation of the image carrier. The area 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 one set of two concentric circles. The region 74 is a region corresponding to one rotation of the image carrier. Region 74 includes image 78. The image 78 is composed of an entire halftone image (image density 40%). First, an image 76 of the area 72 was formed, and then an image 78 of the area 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 rotation based on the rotation of the image 76.

Next, the image obtained after the printing test was used as an image for evaluation. 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, the 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 an image defect (image ghost) caused by the transfer memory was confirmed. The presence or absence of image ghost was evaluated based on the following criteria. Tables 8 and 9 show the obtained evaluation results. The evaluations A to C were regarded as acceptable.
(Image ghost evaluation criteria)
Evaluation A: No image ghost corresponding to the image 76 was observed.
Evaluation B: An image ghost corresponding to the image 76 was slightly observed.
Evaluation C: An image ghost corresponding to the image 76 was observed, but at a level having no practical problem.
Evaluation D: The image ghost corresponding to the image 76 was clearly observed, and 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.

[3-3. Evaluation of Filming Resistance of Single-Layer Photoreceptor]
The filming resistance was evaluated for each of the single-layer photoconductors (A-1) to (A-28) and the single-layer photoconductors (B-1) to (B-6). The evaluation of the filming resistance was performed in an environment at a temperature of 10 ° C. and a relative humidity of 15% RH. As the evaluation machine, the same image forming apparatus used in the evaluation of the image defect was used.

  First, a printing test was performed. Specifically, 5,000 print patterns (image density 1%) were printed on a recording medium (A4 size paper) at intervals of 15 seconds. After the printing test, an evaluation image was prepared. Specifically, one halftone image (image density of 50%) was printed and used as an evaluation image. The evaluation image was visually observed to confirm the presence or absence of image defects (streaks, dash marks) due to filming. Streaks are lines parallel to the printing direction. The 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. Tables 8 and 9 show the obtained evaluation results. The evaluations A to C were regarded as acceptable.

(Evaluation criteria for filming resistance)
Evaluation A: Streaks and dash marks were not observed.
Evaluation B: Streaks and dash marks were slightly observed.
Evaluation C: Streaks and dash marks were partially observed, but at a level having no practical problem.
Evaluation D: Streaks and dash marks were clearly observed as a whole, and were at a practically problematic level.

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

  As shown in Tables 5 and 6, in the photoconductors (A-1) to (A-28), the photosensitive layer includes a charge generator, a hole transport agent, an electron transport agent, filler particles, and a binder resin. And was contained. Specifically, the electron transporting agent contained at least one of the quinone derivative (1) and the diimide derivative (2). The quinone derivative (1) is represented by the general formula (1). The quinone derivative (1) was any one of the quinone derivatives (1-1) to (1-4) and the quinone derivative (1-6). The diimide derivative (2) is represented by the general formula (2). The diimide derivative (2) was any one of the diimide derivatives (2-1) to (2-3) and the diimide derivatives (2-5) to (2-6). The filler particles were any one of F1, F3 to F4, F6 to F7, and F9 to F10.

  As shown in Tables 8 and 9, in the photoconductors (A-1) to (A-28), the comprehensive evaluation results of the transfer memory and the filming resistance were A or B.

  As shown in Table 7, in the photoconductor (B-1), the photosensitive layer did not contain filler particles. In the photoconductors (B-2) to (B-5), the photosensitive layer contained any one of the electron transporting agents (ET-1) to (ET-4) as the electron transporting agent. The electron transporting agents (ET-1) to (ET-4) were neither the quinone derivative (1) nor the diimide derivative (2). In the photoreceptor (B-6), the photosensitive layer contained the filler particles F11. The filler particles F11 were neither silica particles nor resin particles.

  As shown in Table 9, in the photoconductors (B-1) to (B-6), the comprehensive evaluation results of the transfer memory and the filming resistance were C or D.

  Photoconductors (A-1) to (A-28) suppress the occurrence of transfer memory and are excellent in filming resistance as compared with photoconductors (B-1) to (B-6).

  The photoreceptor according to the present invention can be used for 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 (18)

An electrophotographic photosensitive member including a conductive substrate and a photosensitive layer,
The photosensitive layer includes a charge generating agent, a hole transporting agent, at least one selected from the group consisting of a quinone derivative and a diimide derivative, a binder resin, and one or more filler particles,
The quinone derivative is represented by Chemical Formula (1-1), Chemical Formula (1-2), Chemical Formula (1-3), Chemical Formula (1-4), or Chemical Formula (1-6) ,
The diimide derivative is represented by chemical formula (2-1), chemical formula (2-2), chemical formula (2-3), chemical formula (2-5) or chemical formula (2-6) ,
The electrophotographic photoreceptor, wherein the one or more filler particles are silica particles or resin particles.

The photosensitive layer is formed of the chemical formula (1-1), the chemical formula (1-2), the chemical formula (1-3), the chemical formula (1-4), the chemical formula (2-1), the chemical formula (2- The electrophotographic photoreceptor according to claim 1, comprising 3) or a compound represented by the chemical formula (2-6). The volume median diameter of the one or more filler particles is 5nm or more 10μm or less, the electrophotographic photosensitive member according to claim 1 or 2. The electrophotographic photoreceptor according to any one of claims 1 to 3 , wherein the content of the one or more filler particles is 0.5 parts by mass or more and 30 parts by mass or less based on 100 parts by mass of the binder resin. . Wherein the resin particles comprise a fluorine atom, an electrophotographic photosensitive member according to any one of claims 1-4. The electrophotographic photoreceptor according to any one of claims 1 to 5 , wherein the binder resin has a repeating unit represented by the general formula (3) or (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 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 or different from each other,
R ¹⁷ and R ¹⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms which may have a halogen atom;
R ¹⁷ and R ¹⁸ may be the same or different from each other. In the general formula (3),
R ¹¹ and R ¹² represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or a cycloalkylidene group having 5 to 7 carbon atoms formed by bonding to each other;
R ¹³ and R ¹⁴ represent a hydrogen atom 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 R ¹⁷ and R ^18, are identical to each other, electrophotographic photosensitive member according to claim 6. In the general formula (3),
At least one of R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ has one or more halogen atoms;
In the general formula (4),
^{R 15, R 16, R 17} , and at least one of R ^18, but having one or more halogen atoms, an electrophotographic photosensitive member according to claim 6. The electrophotographic photoreceptor according to any one of claims 1 to 8 , wherein the charge generator includes an X-type metal-free phthalocyanine or a Y-type titanyl phthalocyanine. The electrophotographic photoreceptor according to any one of claims 1 to 9 , wherein the hole transporting agent contains a compound represented by the general formula (HTM).

In the general formula (HTM),
Q ⁸ , Q ¹⁰ , Q ¹¹ , Q ¹² , Q ¹³ , and Q ¹⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or Represents a phenyl group,
Q ⁹ and Q ¹⁵ each independently represent an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a phenyl group;
b represents an integer of 0 to 5;
When b represents an integer of 2 to 5, a plurality of Q ⁹ bonded to the same phenyl group may be the same or different from each other;
c represents an integer of 0 to 4;
When c represents an integer of 2 or more and 4 or less, a plurality of Q ¹⁵ bonded to the same phenyl group may be the same or different from each other;
k represents 0 or 1. In the general formula (HTM),
Q ⁸ , Q ¹⁰ , Q ¹¹ , Q ¹² , Q ¹³ , and Q ¹⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,
k represents 0,
The electrophotographic photosensitive member according to claim 10 , wherein b and c represent 0. The electrophotographic photoconductor according to any one of claims 1 to 11 , wherein the photosensitive layer is a single-layer type photosensitive layer. The electrophotograph according to any one of claims 1 to 12 , wherein the photosensitive layer is disposed directly on the conductive substrate, or indirectly disposed via an undercoat layer or an oxide film. Photoconductor. An image carrier;
A charging unit that charges the surface of the image carrier,
Exposure unit that exposes the charged surface of the 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,
A transfer unit that transfers the toner image from the image carrier to a recording medium,
The image bearing member is the electrophotographic photosensitive member according to claim 12 ,
The charging polarity of the charging unit is positive,
The image forming apparatus, wherein the transfer unit transfers the toner image from the image carrier to the recording medium while the surface of the image carrier is in contact with the recording medium. The image forming apparatus according to claim 14 , wherein the charging unit charges the surface of the image carrier while contacting the surface of the image carrier. The developer comprises a polymerized toner, the image forming apparatus according to claim 14 or 15. It further includes a cleaning unit,
The cleaning unit is a cleaning blade, an image forming apparatus according to any one of claims 14-16. Comprising an electrophotographic photosensitive member according to any one of claims 1 to 13, a process cartridge.

Images