JP6508129B2 - Electrophotographic photosensitive member, process cartridge and image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member (hereinafter sometimes referred to as a photosensitive member), a process cartridge, and an image forming apparatus.

  The photoreceptor is used in an electrophotographic image forming apparatus. The photoreceptor comprises a photosensitive layer. As the photosensitive member, a so-called laminated photosensitive member or a single-layered photosensitive member is used. The multi-layer photosensitive member includes, as a photosensitive layer, a charge generation layer having a charge generation function and a charge transport layer having a charge transport function. The single-layer type photosensitive member includes, as a photosensitive layer, a single photosensitive layer having a charge generation function and a charge transport function.

  Patent Document 1 describes a compound represented by chemical formula (2-11) as an electron transporting material (electron transporting agent).

Japanese Patent Application Laid-Open No. 60-69657

  However, in the compound represented by the chemical formula (2-11) described in Patent Document 1, it is difficult to suppress the occurrence of white spots in the formed image.

  The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide an electrophotographic photosensitive member capable of suppressing the occurrence of white spots in a formed image. Another object of the present invention is to provide a process cartridge and an image forming apparatus capable of suppressing the occurrence of white spots in a formed image by providing such an electrophotographic photosensitive member.

  The electrophotographic photosensitive member of the present invention comprises a conductive substrate and a photosensitive layer. The photosensitive layer is a single layer. The photosensitive layer contains a charge generating agent, an electron transporting agent, a hole transporting agent, and a binder resin. The said binder resin contains polycarbonate resin represented by following General formula (1). The said electron transport agent contains the compound represented by following General formula (2).

In the general formula (1), R ¹ , R ² , R ⁵ and R ⁶ each independently represent a halogen atom, an alkyl group having 1 to 6 carbon atoms having one or more halogen atoms, a halogen atom An alkoxy group having 1 to 6 carbon atoms having one or more, an aryl group having 6 to 14 carbon atoms having one or more halogen atoms, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, the number of carbon atoms 1 or more and 6 or less alkoxy groups or C6 or more and 14 or less aryl groups are represented. At least one of R ¹ , R ² , R ⁵ and R ⁶ is a halogen atom, an alkyl group having 1 or more and 6 or less carbon atoms having one or more halogen atoms, or a carbon atom having one or more halogen atoms 1 or more and 6 or less alkoxy groups or an aryl group having 6 or more and 14 or less carbon atoms having one or more halogen atoms. Each of R ³ and R ⁴ independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or 1 to 6 carbon atoms which may have a substituent. The following alkoxy group or an aryl group having 6 to 14 carbon atoms which may have a substituent is shown. Y has a single bond, an alkylene group having 2 to 18 carbon atoms which may have a substituent, an alkylidene group having 1 to 18 carbon atoms which may have a substituent, a substituent Optionally substituted cycloalkyl group having 5 to 15 carbon atoms, optionally substituted cycloalkyl group having 5 to 15 carbon atoms, -S-, -SO-, -O- or Represents -CO-. Each of m and n independently represents a number satisfying the following formulas (i) and (ii).
m + n = 1.0 (i)
0.0 <m ≦ 1.0 (ii)

In the general formula (2), R ⁷ is an alkyl group having 1 to 8 carbon atoms having one or more halogen atoms, a cycloalkyl group having 3 to 10 carbon atoms having one or more halogen atoms, halogen An aryl group having 6 to 14 carbon atoms having one or more atoms and an alkyl group having 1 to 6 carbon atoms, and a 5- or 14-membered heterocyclic ring having one or more halogen atoms And a aralkyl group having 7 or more and 20 or less carbon atoms each having one or more halogen atoms.

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

  An image forming apparatus according to the present invention includes the above-described electrophotographic photosensitive member, a charging unit, an exposure unit, a developing unit, and a transfer unit. The charging unit charges the surface of the electrophotographic photosensitive member. The exposure unit exposes the charged surface of the electrophotographic photosensitive member to form an electrostatic latent image on the surface of the electrophotographic photosensitive member. The developing unit develops the electrostatic latent image as a toner image. The transfer unit transfers the toner image from the electrophotographic photosensitive member to a recording medium. When the transfer unit transfers the toner image from the electrophotographic photosensitive member to the recording medium, the electrophotographic photosensitive member is in contact with the recording medium.

  According to the electrophotographic photosensitive member of the present invention, the occurrence of white spots in a formed image can be suppressed. Further, according to the process cartridge and the image forming apparatus of the present invention, the occurrence of white spots in the formed image can be suppressed by providing such an electrophotographic photosensitive member.

(A), (b), and (c) are partial sectional views which respectively show an example of the photoreceptor concerning embodiment of this invention. It is a figure for demonstrating the method to measure the charge amount of calcium carbonate when making a photosensitive layer and calcium carbonate rub. FIG. 1 is a view showing an example of the configuration of an image forming apparatus provided with a photosensitive member according to an embodiment of the present invention.

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

  Hereinafter, “system” may be added after the compound name to generically generically refer to the compound and its derivative. Moreover, when a "system" is attached after a compound name and it represents a polymer name, it means that the repeating unit of a polymer originates in a compound or its derivative (s). Furthermore, the reactions represented by reaction formulas (R-1) to (R-4) may be described as reactions (R-1) to (R-4), respectively.

  Hereinafter, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms and an aryl group having 6 to 14 carbon atoms have the following meanings unless otherwise specified. It is.

  The halogen atom (halogen group) is, for example, a fluorine atom (fluoro group), a chlorine atom (chloro group), a bromine atom (bromo group) or an iodine atom (iodo group).

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

  The alkoxy group having 1 to 6 carbon atoms is linear or branched and unsubstituted. Examples of the alkoxy group having 1 to 6 carbon atoms include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, s-butoxy group, t-butoxy group, pentyloxy group, iso A pentyloxy group, a neopentyloxy group or a hexyloxy group may be mentioned.

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

<1. Photosensitive body>
The photoreceptor according to the present embodiment includes a conductive substrate and a photosensitive layer. The binder resin contained in the photosensitive layer contains a polycarbonate resin represented by the general formula (1) (hereinafter sometimes referred to as a polycarbonate resin (1)). The electron transfer agent contained in the photosensitive layer contains a compound represented by the general formula (2) (hereinafter sometimes referred to as a compound (2)). When the photosensitive layer contains the polycarbonate resin (1) and the compound (2), the generation of white spots in the formed image can be suppressed. The reason is presumed as follows.

  In order to facilitate understanding, the cause of the occurrence of white spots in the formed image will be described. When the recording medium (for example, paper) and the photosensitive member come into contact in image formation, minute components (for example, paper dust) of the recording medium may be attached to the surface of the photosensitive member. When the minute component of the recording medium adheres to the surface of the photosensitive member, the minute component may block the light exposed on the photosensitive member in the exposure step of image formation. The surface potential of the photosensitive member does not easily decrease in the portion where the exposed light is blocked by the minute component. Since it is difficult for toner to adhere to a portion where the surface potential is not sufficiently reduced, white spots occur in the formed image.

  Here, when the recording medium (for example, paper) and the photosensitive member come into contact in image formation, a minute component (for example, paper powder) of the recording medium is rubbed by the photosensitive member, and the minute component is negative or desired value It may charge to a lower positive polarity. However, the photosensitive layer of the photoreceptor of the present embodiment contains a polycarbonate resin (1) and a compound (2). The polycarbonate resin (1) has a halogen atom and thus has high electronegativity. Since the compound (2) also has a halogen atom, it has high electronegativity. When the minute component is in contact with the photosensitive member of the present embodiment and the minute component is rubbed by the photosensitive member containing the polycarbonate resin (1) having a high electronegativity and the compound (2), the minute component is desired. It can be charged to the positive polarity of a value or more. When the surface of the photosensitive member is charged to positive polarity in the charging step of image formation, the surface of the photosensitive member charged to positive polarity and the minute component having positive polarity of a desired value or more are electrically repelled. The larger the positive value of the charge amount of the minute component, the larger the electrical repulsion with the surface of the photosensitive member. This makes it difficult for the minute component to adhere to the surface of the photosensitive member. As a result, the generation of white spots in the formed image can be suppressed.

  In addition, in order to exert the function as a photosensitive member, it is difficult to extremely increase the content of the binder resin and the content of the electron transfer agent in the photosensitive layer. In the photosensitive member of the present embodiment, the content ratio of halogen atoms in the photosensitive layer can be increased by containing the polycarbonate resin (1) having halogen atoms and the compound (2) having halogen atoms in the photosensitive layer. it can. As a result, the minute component of the recording medium can be charged to the positive polarity of a desired value or more, and the generation of white spots in the formed image can be suitably suppressed.

  The structure of the photosensitive member 1 will be described below with reference to FIG. FIG. 1 is a cross-sectional view showing an example of the photosensitive member 1 according to the present embodiment.

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

  As shown in FIG. 1 (b), the photosensitive member 1 may be provided with a conductive substrate 2, a photosensitive layer 3, and an intermediate layer 4 (undercoat layer). The intermediate layer 4 is provided between the conductive substrate 2 and the photosensitive layer 3. The photosensitive layer 3 may be provided directly on the conductive substrate 2 as shown in FIG. 1 (a), or the photosensitive layer 3 may be an intermediate layer on the conductive substrate 2 as shown in FIG. 1 (b). It may be provided indirectly via 4.

  As shown in FIG. 1C, the photoreceptor 1 may include a conductive substrate 2, a photosensitive layer 3, and a protective layer 5. The protective layer 5 is provided on the photosensitive layer 3.

  The thickness of the photosensitive layer 3 is not particularly limited as long as it can sufficiently exhibit the function as the photosensitive layer. The thickness of the photosensitive layer 3 is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less.

  In order to suppress the generation of white spots in the formed image, the photosensitive layer 3 is preferably disposed as the outermost surface layer of the photosensitive member 1. For the same reason, the photosensitive member 1 is preferably a positively charged single-layer type photosensitive member. The structure of the photosensitive member 1 has been described above with reference to FIG.

<1-1. Photosensitive layer>
The photosensitive layer contains a charge generating agent, an electron transporting agent, a hole transporting agent and a binder resin in one layer. The photosensitive layer may contain an additive, if necessary. Hereinafter, the charge generating agent, the electron transfer agent, the hole transfer agent, the binder resin and the additive will be described.

(Binder resin)
The binder resin contained in the photosensitive layer contains a polycarbonate resin (1). The photosensitive layer contains a polycarbonate resin (1) as a binder resin. Polycarbonate resin (1) is represented by following General formula (1).

First, R ¹ , R ² , R ⁵ and R ⁶ in the general formula (1) will be described. In the general formula (1), R ¹ , R ² , R ⁵ and R ⁶ each independently represent a halogen atom, an alkyl group having 1 to 6 carbon atoms having one or more halogen atoms, a halogen atom Alkoxy group having 1 to 6 carbon atoms, aryl group having 6 to 14 carbon atoms having one or more halogen atoms, hydrogen atom, alkyl group having 1 to 6 carbon atoms, 1 carbon atom Or more represents an alkoxy group having 6 or less and an aryl group having 6 to 14 carbon atoms. At least one of R ¹ , R ² , R ⁵ and R ⁶ is a halogen atom, an alkyl group having 1 or more and 6 or less carbon atoms having one or more halogen atoms, or a carbon atom having one or more halogen atoms 1 or more and 6 or less alkoxy groups or an aryl group having 6 or more and 14 or less carbon atoms having one or more halogen atoms. Therefore, polycarbonate resin (1) always has a halogen atom.

As a halogen atom (halogen group) represented by R ¹ , R ² , R ⁵ and R ⁶ , a chlorine atom (chloro group) or a fluorine atom (fluoro group) is preferable.

When R ¹ , R ² , R ⁵ or R ⁶ represents an alkyl group having 1 to 6 carbon atoms having one or more halogen atoms, the alkyl group having 1 to 6 carbon atoms has 1 carbon atom. An alkyl group of 3 or more and 3 or less is preferable, and a methyl group is more preferable. It is preferable that the halogen atom which the C1-C6 alkyl group has is a chloro group or a fluoro group. The number of halogen atoms contained in the alkyl group having 1 to 6 carbon atoms is preferably 1 or more and 3 or less. The alkyl group having 1 to 6 carbon atoms having one or more halogen atoms represented by R ¹ , R ² , R ⁵ and R ⁶ includes 1 to 3 carbon atoms having one or more and three or less halogen atoms. Alkyl groups are preferred, and trifluoromethyl is more preferred.

When R ¹ , R ² , R ⁵ or R ⁶ represents an alkoxy group having 1 to 6 carbon atoms having one or more halogen atoms, the alkoxy group having 1 to 6 carbon atoms has 1 carbon atom More than 3 or less alkoxy groups are preferable. It is preferable that the halogen atom which a C1-C6 alkoxy group has is a chloro group or a fluoro group. The number of halogen atoms contained in the alkoxy group having 1 to 6 carbon atoms is preferably 1 or more and 3 or less. The alkoxy group having 1 to 6 carbon atoms having one or more halogen atoms represented by R ¹ , R ² , R ⁵ and R ⁶ includes 1 to 3 carbon atoms having one or more and three or less halogen atoms. Alkoxy groups are preferred.

When R ¹ , R ² , R ⁵ or R ⁶ represents an aryl group having 6 to 14 carbon atoms having one or more halogen atoms, the aryl group having 6 to 14 carbon atoms has 6 carbon atoms An aromatic monocyclic hydrocarbon group having 14 or more and 14 or less is preferable, and a phenyl group is more preferable. The halogen atom contained in the aryl group having 6 to 14 carbon atoms is preferably a chloro group or a fluoro group, and more preferably a fluoro group. The number of halogen atoms contained in the aryl group having 6 to 14 carbon atoms is preferably 1 or more and 3 or less, and more preferably one. The aryl group having 6 to 14 carbon atoms having one or more halogen atoms represented by R ¹ , R ² , R ⁵ and R ^{6 includes 6} to 14 carbon atoms having one to three halogen atoms. Are preferably an aryl group of 6 to 14 carbon atoms having one or more and three or less halogen atoms, more preferably a fluorophenyl group, further preferably a p (para) -fluorophenyl group. Is particularly preferred.

As an alkyl group having 1 to 6 carbon atoms represented by R ¹ , R ² , R ⁵ and R ⁶ , an alkyl group having 1 to 3 carbon atoms is preferable, and a methyl group is more preferable.

As an alkoxy group having 1 to 6 carbon atoms represented by R ¹ , R ² , R ⁵ and R ^6, an alkoxy group having 1 to 3 carbon atoms is preferable.

As an aryl group having 6 to 14 carbon atoms represented by R ¹ , R ² , R ⁵ and R ^6, an aromatic monocyclic hydrocarbon group having 6 to 14 carbon atoms is preferable, and a phenyl group is more preferable.

The bonding position of R ¹ and R ² is not particularly limited. R ¹ is bonded to the ortho or para position of the phenyl group with respect to the oxygen atom to which the phenyl group is bonded. R ^{2 is} also bonded to the ortho or para position of the phenyl group with respect to the oxygen atom to which the phenyl group is bonded. Each of R ¹ and R ² is preferably bonded to the ortho of the phenyl group with respect to the oxygen atom to which the phenyl group is bonded.

In order to suppress the occurrence of white spots in the formed image, each of R ¹ , R ² , R ⁵ and R ⁶ independently has a halogen atom or one or more halogen atoms, and has 1 to 6 carbon atoms. And R represents an alkyl group, an aryl group having 6 to 14 carbon atoms having one or more halogen atoms, a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and among R ¹ , R ² , R ⁵ and R ⁶ Preferably, at least one of them represents a halogen atom, an alkyl group having 1 to 6 carbon atoms having one or more halogen atoms, or an aryl group having 6 to 14 carbon atoms having one or more halogen atoms.

In a preferred example for suppressing the occurrence of white spots in the formed image, R ¹ and R ² each represent a hydrogen atom, and one or both of R ⁵ and R ⁶ have one or more halogen atoms, and one carbon atom It represents an aryl group having 6 to 14 carbon atoms having one or more alkyl groups or halogen atoms of 6 or more.

In another preferable example for suppressing the occurrence of white spots in the formed image, R ¹ and R ² each represent a halogen atom, and R ⁵ and R ⁶ each represent an alkyl group having 1 to 6 carbon atoms. .

  In order to suppress the occurrence of white spots in the formed image, the number of halogen atoms in the polycarbonate resin (1) is preferably large. The number of halogen atoms in the polycarbonate resin (1) is preferably 1 or more and 6 or less, more preferably 2 or more and 6 or less, and particularly preferably 6 or more.

Next, R ³ and R ⁴ in the general formula (1) will be described. In the general formula (1), each of R ³ and R ⁴ independently has a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or a substituent It represents an aryl group having 6 to 14 carbon atoms which may have an alkoxy group having 1 to 6 carbon atoms or a substituent.

As an alkyl group having 1 to 6 carbon atoms represented by R ³ and R ⁴ , an alkyl group having 1 to 3 carbon atoms is preferable. The alkyl group having 1 to 6 carbon atoms represented by R ³ and R ⁴ may have a substituent. It is preferable that the substituent which the C1-C6 alkyl group has is except a halogen atom. Examples of the substituent that the alkyl group having 1 to 6 carbon atoms has are an alkoxy group having 1 to 6 carbon atoms or an aryl group having 6 to 14 carbon atoms. The number of substituents which the alkyl group having 1 to 6 carbon atoms has is, for example, 1 or more and 3 or less.

The alkoxy group having 1 to 6 carbon atoms represented by R ³ and R ⁴ is preferably an alkoxy group having 1 to 3 carbon atoms. The alkoxy group having 1 to 6 carbon atoms represented by R ³ and R ⁴ may have a substituent. The substituent which the alkoxy group having 1 to 6 carbon atoms has is preferably other than a halogen atom. Examples of the substituent which the alkoxy group having 1 to 6 carbon atoms has are an alkoxy group having 1 to 6 carbon atoms or an aryl group having 6 to 14 carbon atoms. The number of substituents which the alkoxy group having 1 to 6 carbon atoms has is, for example, 1 or more and 3 or less.

As an aryl group having 6 to 14 carbon atoms represented by R ³ and R ^4, an aromatic monocyclic hydrocarbon group having 6 to 14 carbon atoms is preferable, and a phenyl group is more preferable. The aryl group having 6 to 14 carbon atoms represented by R ³ and R ⁴ may have a substituent. The substituent which the aryl group having 6 to 14 carbon atoms has is preferably other than a halogen atom. Examples of the substituent that the aryl group having 6 to 14 carbon atoms has are an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms. It is. The number of substituents which the aryl group having 6 to 14 carbon atoms has is, for example, 1 or more and 3 or less.

The bonding position of R ³ and R ⁴ is not particularly limited. R ³ is bonded to the ortho or para position of the phenyl group with respect to the oxygen atom to which the phenyl group is bonded. R ^{4 is} also bonded to the ortho or para position of the phenyl group with respect to the oxygen atom to which the phenyl group is bonded. Each of R ³ and R ⁴ is preferably bonded to the ortho of the phenyl group with respect to the oxygen atom to which the phenyl group is bonded.

In order to suppress the occurrence of white spots in the formed image, each of R ³ and R ⁴ preferably represents a hydrogen atom.

  Next, Y in the general formula (1) will be described. In the general formula (1), Y is a single bond, an alkylene group having 2 to 18 carbon atoms which may have a substituent, or 1 to 18 carbon atoms which may have a substituent An alkylidene group, a cycloalkylene group having 5 to 15 carbon atoms which may have a substituent, a cycloalkylidene group having 5 to 15 carbon atoms which may have a substituent, -S-,- Represents SO-, -O- or -CO-;

  The alkylene group having 2 to 18 carbon atoms represented by Y is linear or branched, and is a divalent group in which one bond is bonded to each of carbon atoms located at both ends of the alkyl group. It is. Examples of the alkylene group having 2 to 18 carbon atoms include ethylene group, n-propylene group, methyl ethylene group, n-butylene group, methyl propylene group, dimethyl ethylene group, ethyl ethylene group, pentylene group, hexylene group, A heptylene group, octylene group, nonylene group, decylene group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene group or octadecylene group can be mentioned. As an alkylene group having 2 to 18 carbon atoms, an alkylene group having 2 to 6 carbon atoms is preferable. The alkylene group having 2 to 18 carbon atoms represented by Y may have a substituent. It is preferable that the substituent which an alkylene group having 2 to 18 carbon atoms has is other than a halogen atom. An example of the substituent which an alkylene group having 2 to 18 carbon atoms has is an alkoxy group having 1 to 6 carbon atoms or a phenyl group. The number of substituents which an alkylene group having 2 to 18 carbon atoms has is, for example, 1 or more and 3 or less.

The alkylidene group having 1 to 18 carbon atoms represented by Y is linear or branched, and is a divalent group in which two bonds are bonded to one carbon atom. Examples of the alkylidene group having 1 to 18 carbon atoms include a methylidene group, an ethylidene group, an n-propylidene group, a dimethylmethylidene group (= C (CH ₃ ) ₂ ), an n-butylidene group and an ethylmethylmethylidene group. (= C (CH ₃ ) (CH ₂ CH ₃ )), pentylidene group, isopentylidene group, neopentylidene group, hexylidene group, heptylidene group, octylidene group, nonylidene group, decylidene group, undecylidene group, dodecylylidene group, tolidylidene Groups, tetradecylidene group, pentadecylidene group, hexadecylidene group, heptadecylidene group or octadecylidene group. As the alkylidene group having 1 or more and 18 or less carbon atoms, an alkylidene group having 1 or more and 6 or less carbon atoms is preferable, and a dimethyl methylidene group (= C (CH ₃ ) ₂ ) or an ethyl methyl methylidene group (ジ メ チ ル C (CH ₂ ) is preferable. ₃ ) (CH ₂ CH ₃ )) is more preferred. The alkylidene group having 1 to 18 carbon atoms represented by Y may have a substituent. The substituent that the alkylidene group having 1 to 18 carbon atoms has is preferably other than a halogen atom. An example of the substituent which the alkylidene group having 1 to 18 carbon atoms has is an alkoxy group having 1 to 6 carbon atoms or a phenyl group. The number of substituents which the alkylidene group having 1 to 18 carbon atoms has is, for example, 1 or more and 3 or less.

  The cycloalkylene group having 5 to 15 carbon atoms represented by Y is a divalent group in which one bond is bonded to each of two carbon atoms among carbon atoms forming the cycloalkane. As a cycloalkylene group having 5 to 15 carbon atoms, for example, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclooctylene group, a cyclononylene group, a cyclodecylene group, a cycloundecylene group, a cyclododecylene group, a cyclotridecylene group , Cyclotetradecylene group or cyclopentadecylene group. The cycloalkylene group having 5 to 15 carbon atoms is preferably a cycloalkylene group having 5 to 7 carbon atoms. The cycloalkylene group having 5 to 15 carbon atoms represented by Y may have a substituent. It is preferable that the substituent which a C5-C15 cycloalkylene group has is except a halogen atom. Examples of the substituent which the cycloalkylene group having 5 to 15 carbon atoms has are an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. The number of substituents which the cycloalkylene group having 5 to 15 carbon atoms has is, for example, 1 or more and 3 or less.

  The cycloalkylidene group having 5 to 15 carbon atoms represented by Y is a divalent group in which two bonds are bonded to one carbon atom of carbon atoms forming a cycloalkane. As a cycloalkylidene group having 5 to 15 carbon atoms, for example, a cyclopentylidene group, a cyclohexylidene group, a cycloheptylidene group, a cyclooctylidene group, a cyclononylidene group, a cyclodecylidene group, a cycloundecylidene group , Cyclododecylidene group, cyclotridecylidene group, cyclotetradecylidene group or cyclopentadecylidene group. As a cycloalkylidene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 7 carbon atoms is preferable, and a cyclohexylidene group is more preferable. The cycloalkylidene group having 5 to 15 carbon atoms represented by Y may have a substituent. The substituent that the cycloalkylidene group having 5 to 15 carbon atoms has is preferably other than a halogen atom. Examples of the substituent that the cycloalkylidene group having 5 to 15 carbon atoms has are an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. The number of substituents which the cycloalkylidene group having 5 to 15 carbon atoms has is, for example, 1 or more and 3 or less.

  In order to suppress the occurrence of white spots in the formed image, Y preferably represents a cycloalkylidene group having 5 to 15 carbon atoms, and more preferably represents a cycloalkylidene group having 5 to 7 carbon atoms. It is particularly preferable to represent a cyclohexylidene group.

Next, m and n in the general formula (1) will be described. The polycarbonate resin (1) is a repeating structural unit represented by the following general formula (5) (hereinafter sometimes referred to as a repeating unit (5)) and a repeating structural unit represented by the general formula (6) Hereinafter, it may be described as a repeating unit (6). Polycarbonate resin (1) is a copolymer of repeating unit (5) and repeating unit (6). Incidentally, R ¹ in the general formula (5), R ^2, R ⁵ and R ⁶ have the same meanings as R ^1, R ^2, R ⁵ and R ⁶ each general formula (1). R ^3, R ⁴ and Y in the general formula (6) have the same meanings as those in general formula (1) R ^3, R ⁴ and Y.

  In the general formula (1), m represents the mass (number of moles) of the repeating unit (5) relative to the total mass (number of moles) of the repeating unit (5) and the repeating unit (6) in the polycarbonate resin (1) Represents the ratio (molar ratio) of N in the general formula (1) is the amount of substance (number of moles) of the repeating unit (6) relative to the total amount (number of moles) of the repeating unit (5) and the repeating unit (6) in the resin (1) It represents a ratio (molar ratio).

In general formula (1), m and n each independently represent a number satisfying the following formulas (i) and (ii). m represents a number greater than 0.0. Since m is not 0.0, the polycarbonate resin (1) always has a repeating unit (5). On the other hand, the polycarbonate resin (1) may or may not have the repeating unit (6). For example, when m is 1.0, n is 0.0. When m is 1.0, polycarbonate resin (1) has only repeating unit (5). When m is 1.0, the carbonate resin (1) has no repeating unit (6).
m + n = 1.0 (i)
0.0 <m ≦ 1.0 (ii)

  Formula (ii) is preferably 0.2 ≦ m ≦ 0.8, more preferably 0.3 ≦ m ≦ 0.7, and 0.4 ≦ m ≦ 0.6. Particularly preferred. It becomes easy to suppress generation | occurrence | production of the white spot in a formation image as m is 0.2 or more. It is thought that the solubility of polycarbonate resin (1) with respect to the solvent contained in the coating liquid for photosensitive layers can be improved as m is 0.8 or less. In addition, it is considered that the oil crack resistance of the photosensitive layer can be improved when m is 0.8 or less. The oil crack is a phenomenon in which a crack is generated on the surface of the photosensitive member when the oil or other oil of the finger adheres to the surface (for example, the photosensitive layer) of the photosensitive member.

  The polycarbonate resin (1) may be a random copolymer in which the repeating units (5) and the repeating units (6) are randomly copolymerized. Alternatively, the polycarbonate resin (1) may be an alternating copolymer in which repeating units (5) and repeating units (6) are copolymerized alternately. Alternatively, the polycarbonate resin (1) may be a periodic copolymer in which one or more repeating units (5) and one or more repeating units (6) are periodically copolymerized. Alternatively, the polycarbonate resin (1) may be a block copolymer obtained by copolymerizing a block consisting of a plurality of repeating units (5) and a block consisting of a plurality of repeating units (6).

  A specific example of the polycarbonate resin (1) is a polycarbonate resin represented by the following chemical formula (1-1), (1-2), (1-3) or (1-4).

  The viscosity average molecular weight of the polycarbonate resin (1) is preferably 25,000 or more, more preferably 25,000 or more and 52,500 or less. When the viscosity average molecular weight of the polycarbonate resin (1) is 25,000 or more, the abrasion resistance of the photoreceptor is easily improved. When the viscosity average molecular weight of the polycarbonate resin (1) is 52,500 or less, the polycarbonate resin (1) is easily dissolved in the solvent when forming the photosensitive layer, and the viscosity of the coating solution for photosensitive layer does not become too high. As a result, it becomes easy to form a photosensitive layer.

The method for producing the polycarbonate resin (1) is not particularly limited as long as the polycarbonate resin (1) can be produced. As an example of the manufacturing method of polycarbonate resin (1), the method (what is called the phosgene method) of condensation-polymerizing the diol compound and phosgene for comprising the repeating unit of polycarbonate resin (1) is mentioned. More specifically, for example, a method of subjecting a diol compound represented by the following general formula (7), a diol compound represented by the following general formula (8), and phosgene to condensation polymerization can be mentioned. Incidentally, R ¹ in the general formula (7), R ^2, R ³ and R ⁴ are the same with each R ¹ in the general formula (1) in, R ^2, R ³ and R ^4. R ^3, R ⁴ and Y in the general formula (8) has the same meaning as R ^3, R ⁴ and X each in the general formula (1). As another example of the method for producing the polycarbonate resin (1), a method in which a diol compound and diphenyl carbonate are transesterified is also mentioned.

  The photosensitive layer may further contain a binder resin other than the polycarbonate resin (1) (hereinafter sometimes referred to as another binder resin) in addition to the polycarbonate resin (1). As other binder resin, thermoplastic resins other than polycarbonate resin, thermosetting resin, or photocurable resin are mentioned, for example. Examples of thermoplastic resins other than polycarbonate resin are polyarylate resin, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic acid polymer, styrene-acrylic acid copolymer, Polyethylene resin, ethylene-vinyl acetate copolymer, chlorinated polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer resin, vinyl chloride-vinyl acetate copolymer, alkyd resin, polyamide resin, urethane resin, polysulfone resin, diallyl phthalate Resin, ketone resin, polyvinyl butyral resin, polyester resin or polyether resin. Examples of thermosetting resins are silicone resins, epoxy resins, phenolic resins, urea resins or melamine resins. Examples of photocurable resins are epoxy acrylates (acrylic acid adducts of epoxy compounds) or urethane-acrylates (acrylic acid adducts of urethane compounds). One of these binder resins may be used alone, or two or more thereof may be used in combination.

  When the photosensitive layer contains another binder resin, the content of the polycarbonate resin (1) is preferably 80% by mass or more, and more preferably 90% by mass or more based on the total mass of the binder resin. Preferably, it is 100% by mass. The total mass of the binder resin is the sum of the mass of the polycarbonate resin (1) and the mass of the other binder resin.

(Electron transport agent)
The electron transfer agent contained in the photosensitive layer contains the compound (2). The photosensitive layer contains the compound (2) as an electron transfer agent. The compound (2) is represented by the following general formula (2). The compound (2) is a malononitrile derivative.

In the general formula (2), R ⁷ is an alkyl group having 1 to 8 carbon atoms having one or more halogen atoms; a cycloalkyl group having 3 to 10 carbon atoms having one or more halogen atoms; halogen atoms An aryl group having 6 to 14 carbon atoms which may have an alkyl group having 1 to 6 carbon atoms; a 5- or 14-membered heterocyclic ring having one or more halogen atoms Or a group having 7 or more and 20 or less carbon atoms having one or more halogen atoms.

The alkyl group having 1 to 8 carbon atoms represented by R ^{7 in the} general formula (2) is linear or branched. Examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, pentyl group, isopentyl group, neopentyl group , Hexyl, heptyl or octyl. As an alkyl group having 1 to 8 carbon atoms, an alkyl group having 1 to 6 carbon atoms is preferable, an alkyl group having 3 to 5 carbon atoms is more preferable, and n-propyl group, n-butyl group or The neopentyl group is more preferred, and the n-butyl group is particularly preferred. The alkyl group having 1 to 8 carbon atoms represented by R ⁷ has one or more halogen atoms. The halogen atom contained in the alkyl group having 1 to 8 carbon atoms represented by R ⁷ is preferably a chloro group or a fluoro group, and more preferably a chloro group. The number of halogen atoms possessed by the alkyl group having 1 to 8 carbon atoms represented by R ⁷ is preferably one or two, and more preferably one.

Examples of the cycloalkyl group having 3 to 10 carbon atoms represented by R ⁷ include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group and cyclodecyl group. The cycloalkyl group having 3 to 10 carbon atoms has one or more halogen atoms. Halogen atom of the cycloalkyl group having not more than 3 or more carbon atoms 10 R ⁷ represents is preferably a chloro group or a fluoroalkyl group. It is preferable that the number of halogen atoms which the cycloalkyl group having 3 to 10 carbon atoms represented by R ⁷ has is one or two.

The aryl group having 6 to 14 carbon atoms represented by R ⁷ is preferably a phenyl group. The aryl group having 6 to 14 carbon atoms represented by R ⁷ has one or more halogen atoms. The halogen atom of the aryl group having 6 to 14 carbon atoms represented by R ⁷ is preferably a chloro group or a fluoro group, and more preferably a chloro group. The number of halogen atoms possessed by the aryl group having 6 to 14 carbon atoms represented by R ⁷ is preferably one or two. The aryl group having 6 to 14 carbon atoms may further have an alkyl group having 1 to 6 carbon atoms in addition to the halogen atom.

The 5- to 14-membered heterocyclic group represented by R ⁷ contains at least one hetero atom in addition to a carbon atom. The hetero atom is one or more selected from the group consisting of nitrogen atom, sulfur atom and oxygen atom. The 5- to 14-membered heterocyclic group is, for example, a 5- or 6-membered monocyclic heterocyclic group containing 1 to 3 hetero atoms in addition to carbon atoms; such a monocyclic heterocyclic ring A heterocyclic group in which 2 such groups are fused; a heterocyclic group in which such a monocyclic heterocyclic ring and a 5- or 6-membered monocyclic hydrocarbon ring are fused; 3 such monocyclic heterocyclic rings A fused heterocyclic group; a heterocyclic group in which two such monocyclic heterocycles and one 5- or 6-membered monocyclic hydrocarbon ring are fused; or such a monocyclic heterocycle 1 And heterocyclic groups in which two 5-membered or 6-membered monocyclic hydrocarbon rings are fused. Specific examples of 5- to 14-membered heterocyclic groups include piperidinyl, piperazinyl, morpholinyl, thiophenyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl, isothiazolyl, isoxazolyl, oxazolyl, 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 Group, triazolyl group, tetrazolyl group, 4H-quinolizinyl group, naphthyridinyl group, benzofuranyl group, 1,3-benzodioxolyl group, benzoxazolyl group, benzothiazolyl group, benzimidazolyl group, Rubazoriru group, phenanthridinyl group, acridinyl group, phenazinyl group or include phenanthrolinyl group. As the 5- to 14-membered heterocyclic group, a 5- or 6-membered monocyclic heterocyclic group containing 1 to 3 hetero atoms (preferably nitrogen atoms) in addition to carbon atoms is preferable, and pyridyl is preferred. Groups are more preferred. The 5- to 14-membered heterocyclic group represented by R ⁷ has one or more halogen atoms. It is preferable that the halogen atom which the heterocyclic group of 5 to 14 members represented by R ⁷ has is a chloro group or a fluoro group. The number of halogen atoms possessed by the 5- to 14-membered heterocyclic group represented by R ⁷ is preferably one or two.

The aralkyl group having 7 to 20 carbon atoms represented by R ⁷ is an alkyl group having 1 to 6 carbon atoms in which an aryl group having 6 to 14 carbon atoms is bonded. The aralkyl group having 7 to 20 carbon atoms is preferably an alkyl group having 1 to 6 carbon atoms to which a phenyl group is bonded, and more preferably a phenylmethyl group (benzyl group) or a phenylethyl group. The aralkyl group having 7 to 20 carbon atoms represented by R ⁷ has one or more halogen atoms. Halogen atoms having an aralkyl group 20 or less carbon atoms 7 or more R ⁷ represents is preferably a chloro group or a fluoroalkyl group. The number of halogen atoms possessed by the aralkyl group having 7 to 20 carbon atoms which R ⁷ represents is preferably one or two.

In the general formula (2), bonding position of the group represented by the general formula "-COOR ^7" (substitution position) it is not particularly limited. Group represented by the general formula "-COOR ^7" is # 1 out of the following chemical formula, 2-position, may be bonded to any position of the 3-position and 4-position. The group represented by the general formula “—COOR ⁷ ” is preferably bonded to the 1-, 2- or 4-position in the following chemical formula, and more preferably to the 1- or 4-position.

In order to suppress the occurrence of white spots in the formed image, R ⁷ is an alkyl group having 1 to 8 carbon atoms having one or two halogen atoms, or a carbon atom having one or two halogen atoms It is preferable to represent several 7 or more and 20 or less aralkyl groups.

  In order to suppress the generation of white spots in the formed image, it is preferable that the number of halogen atoms in the compound (2) is large. The number of halogen atoms contained in the polycarbonate resin (2) is preferably one or two, and more preferably two.

  Specific examples of the compound (2) are compounds represented by the following chemical formulas (2-1) to (2-10) (hereinafter, sometimes described as compounds (2-1) to (2-10)) is there. Among them, compounds (2-1), (2-5) and (2-10) are preferable.

Compound (2) is produced, for example, according to or following a reaction (R-1) or (R-2) described below. In addition to these reactions, appropriate steps may be included as necessary. R ⁷ in the reaction formula shown in the reaction (R-1) and (R-2) has the same meaning as R ⁷ in the general formula (2). In addition, compounds represented by the following chemical formula (A), general formula (B), general formula (C) and chemical formula (D) are respectively compound (A), (B), (C) and (D) May be described.

  In the reaction (R-1), 1 molar equivalent of a compound (A) and 1 molar equivalent of a compound (B) are reacted to obtain 1 molar equivalent of a compound (C). It is preferable to add 1 mole or more and 5 moles or less of the compound (B) to 1 mole of the compound (A). It is preferable that the reaction temperature of reaction (R-1) is 80 degreeC or more and 150 degrees C or less. The reaction time of the reaction (R-1) is preferably 2 hours or more and 10 hours or less.

  The reaction (R-1) may be carried out in the presence of a catalyst. As a catalyst, an acid catalyst is mentioned, for example, More specifically, p-toluenesulfonic acid, camphorsulfonic acid or pyridinium-p-toluenesulfonic acid is mentioned. One of these catalysts may be used alone, or two or more thereof may be used in combination. The addition amount of the catalyst is preferably a small amount, specifically 0.01 mol or more and 0.5 mol or less, per 1 mol of the compound (A).

  The reaction (R-1) may be carried out in a solvent. As the solvent, for example, ethers (specifically, tetrahydrofuran, diethyl ether or dioxane), halogenated hydrocarbons (specifically, methylene chloride, chloroform or dichloroethane) or aromatic hydrocarbons (specifically, And benzene or toluene).

  In the reaction (R-2), 1 molar equivalent of a compound (C) and 1 molar equivalent of a compound (D, malononitrile) are reacted to obtain 1 molar equivalent of a compound (2). It is preferable to add 1 mole or more and 5 moles or less of the compound (D) to 1 mole of the compound (C). It is preferable that the reaction temperature of reaction (R-2) is 40 degreeC or more and 120 degrees C or less. The reaction time of the reaction (R-2) is preferably 1 hour or more and 10 hours or less.

  The reaction (R-2) may be carried out in the presence of a catalyst. The catalyst includes, for example, a base catalyst, and more specifically, piperidine and piperazine.

  The reaction (R-2) may be carried out in a solvent. As a solvent, a polar solvent is mentioned, More specifically, methanol, ethanol, n-propanol, acetone or dioxane is mentioned.

  The reaction product obtained in the reaction (R-2) may be purified, if necessary, to isolate the target compound, compound (2). A well-known method is suitably employ | adopted as a purification method. Purification may be performed, for example, by crystallization or silica gel chromatography. Examples of the solvent used for purification include chloroform.

  The photosensitive layer may contain, in addition to the compound (2), an electron transfer agent other than the compound (2) (hereinafter, may be described as another electron transfer agent). Examples of other electron transfer agents include quinone compounds, diimide compounds, hydrazone compounds, thiopyran compounds, trinitrothioxanthone compounds, 3,4,5,7-tetranitro-9-fluorenone compounds, dinitroanthracene compounds Compounds, dinitroacridine compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroacridine, succinic anhydride, maleic anhydride or dibromomaleic anhydride. Examples of quinone compounds are diphenoquinone compounds, azoquinone compounds, anthraquinone compounds, naphthoquinone compounds, nitroanthraquinone compounds or dinitroanthraquinone compounds. One of the other electron transport agents may be used alone, or two or more thereof may be used in combination.

  When the photosensitive layer contains another electron transfer agent in addition to the compound (2), the content of the compound (2) is preferably 80% by mass or more based on the total mass of the electron transfer agent, and 90 It is more preferable that it is mass% or more, and it is especially preferable that it is 100 mass%.

  The content of the compound (2) as the electron transfer agent is preferably 20 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the binder resin. When the content of the compound (2) is at least 20 parts by mass with respect to 100 parts by mass of the binder resin, the electrical characteristics of the photoreceptor can be easily improved. If the content of the compound (2) is 40 parts by mass or less based on 100 parts by mass of the binder resin, the compound (2) is easily dissolved in the solvent for forming the photosensitive layer, and a uniform photosensitive layer is formed. It will be easier.

(The amount of triboelectric charge of calcium carbonate)
The charge amount of calcium carbonate (hereinafter sometimes referred to as the charge amount of calcium carbonate) when the photosensitive layer and calcium carbonate are rubbed is preferably 7.0 μC / g or more. Calcium carbonate is a main component of paper dust which is an example of a minute component of the recording medium. When the charge amount of calcium carbonate is 7.0 μC / g or more, when the photoreceptor and the minute component of the recording medium rub, the minute component of the recording medium tends to be favorably positively charged. When the surface of the photosensitive member is positively charged in the charging step of image formation, the surface of the positively charged photosensitive member electrically repels the minute component of the recording medium having the positive polarity. This makes it difficult for the minute components of the recording medium to adhere to the surface of the photosensitive member. As a result, the generation of white spots in the formed image can be further suppressed. The charge amount of calcium carbonate is preferably 7.0 μC / g or more and 15.0 μC / g or less, more preferably 9.0 μC / g or more and 15.0 μC / g or less, and 9.0 μC / g or more It is particularly preferable that it is 13.5 μC / g or less.

  Hereinafter, with reference to FIG. 2, a method of measuring the charge amount of calcium carbonate when the photosensitive layer 3 and the calcium carbonate are rubbed will be described. The charge amount of calcium carbonate is measured by performing the first step, the second step, the third step and the fourth step. In the first step, two photosensitive layers 3 are prepared. One of the photosensitive layers 3 is a first photosensitive layer 30. The other of the photosensitive layers 3 is a second photosensitive layer 32. The first photosensitive layer 30 and the second photosensitive layer 32 have a circular shape of 3 cm in diameter. In the second step, 0.007 g of calcium carbonate is placed on the first photosensitive layer 30. Thereby, a calcium carbonate layer 24 composed of calcium carbonate is formed. Subsequently, the second photosensitive layer 32 is placed on the calcium carbonate layer 24. In the third step, the first photosensitive layer 30 is rotated at a rotational speed of 60 rpm for 60 seconds while the second photosensitive layer 32 is fixed under an environment of a temperature of 23 ° C. and a relative humidity of 50% RH. Thereby, the calcium carbonate contained in the calcium carbonate layer 24 is rubbed between the first photosensitive layer 30 and the second photosensitive layer 32 to charge the calcium carbonate. In the fourth step, charged calcium carbonate is sucked using a charge amount measuring device. The total charge amount Q and mass M of the sucked calcium carbonate are measured using a charge amount measuring device, and the charge amount of calcium carbonate is calculated from the formula “charge amount = Q / M”. The charge amount of calcium carbonate is specifically measured by the method described in the examples. In the above, with reference to FIG. 2, the method of measuring the charge amount of calcium carbonate when making the photosensitive layer 3 and calcium carbonate rub is demonstrated.

(Hole transport agent)
The photosensitive layer contains, for example, a hole transport agent. Examples of the hole transport agent include triphenylamine derivatives, diamine derivatives (eg, N, N, N ′, N′-tetraphenylbenzidine derivatives, N, N, N ′, N′-tetraphenylphenylenediamine derivatives, N, N, N ', N'-tetraphenyl naphthyl didiamine derivative, N, N, N', N'-tetraphenyl phenanthrylene diamine derivative or di (aminophenyl ethenyl) benzene derivative), oxadiazole type A compound (for example, 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole), a styryl compound (for example, 9- (4-diethylaminostyryl) anthracene), a carbazole compound (for example, , Polyvinylcarbazole), organic polysilane compounds, pyrazoline compounds (eg, 1-phenyl-3- (p-) Methylamino phenyl) pyrazoline), hydrazone compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compound, or triazole-based compounds. One type of hole transport agent may be used alone, or two or more types may be used in combination.

  The hole transfer agent is a compound represented by the following general formula (3) (hereinafter, may be described as a compound (3)) or a compound represented by the following general formula (4) (hereinafter, the compound (4) It may be preferable to include The hole transfer agent is more preferably the compound (3) in order to suppress the occurrence of white spots in the formed image. First, the compound (3) will be described.

In the general formula (3), R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ each independently represent a hydrogen atom And an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms.

When the photosensitive layer contains the compound (2) as an electron transfer agent and the compound (3) as a hole transfer agent, generation of white spots in the formed image is suppressed without impairing the electrical properties of the photosensitive layer. be able to. Further, it is considered that the occurrence of oil cracks in the photosensitive layer can be suppressed by the photosensitive layer containing the polycarbonate resin (1) and the compound (3). Since R ^{8 to} R ¹⁹ possessed by the compound (3) are not conjugated groups such as an alkenyl group or an aryl group, the molecular weight of the compound (3) is relatively small. The compound (3) having such a chemical structure is considered to fill the voids (microvoids) of the photosensitive layer by containing the compound (3) having such a chemical structure in combination with the polycarbonate resin (1) in the photosensitive layer. It is.

As an alkyl group having 1 to 6 carbon atoms represented by R ^{8 to} R ¹⁹ , an alkyl group having 1 to 3 carbon atoms is preferable, a methyl group or an ethyl group is more preferable, and a methyl group is particularly preferable.

As an alkoxy group having 1 to 6 carbon atoms represented by R ^{8 to} R ^19, an alkoxy group having 1 to 3 carbon atoms is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is particularly preferable.

In order to suppress the generation of white spots in the formed image, in general formula (3), R ^{8 to} R ¹⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. More preferably, it represents a hydrogen atom, a methyl group, an ethyl group, a methoxy group or an ethoxy group, and particularly preferably a hydrogen atom or a methyl group.

In order to suppress the occurrence of white spots in the formed image, R ⁸ and R ^{11 in} the general formula (3) are preferably the same group. R ⁹ and R ¹² are preferably the same group. It is preferable that R ¹⁰ and R ¹³ be the same group.

In order to suppress the generation of white spots in the formed image, in general formula (3), R ^{14 to} R ¹⁹ preferably represent a hydrogen atom.

  Specific examples of the compound (3) are compounds represented by the following chemical formulas (3-1) to (3-4) (hereinafter, sometimes described as compounds (3-1) to (3-4)) is there. Among these, the compound (3-1) is preferable.

  Next, the compound (4) will be described.

In the general formula (4), each of R ^{20 to} R ²⁵ independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl having 6 to 14 carbon atoms. Represents a group. R ^{20 to} R ²⁵ each preferably represent an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and representing a methyl group or an ethyl group Is particularly preferred.

In the general formula (4), a, b, c and d each independently represent an integer of 0 or more and 5 or less. When a represents an integer of 2 or more and 5 or less, a plurality of R ²⁰ bonded to the same phenyl group may be the same or different. When b represents an integer of 2 or more and 5 or less, a plurality of R ²¹ bonded to the same phenyl group may be the same or different. When c represents an integer of 2 or more and 5 or less, a plurality of R ²² bonded to the same phenyl group may be the same or different. When d represents an integer of 2 or more and 5 or less, plural R ²³ bonded to the same phenyl group may be the same or different. Preferably, a and b each represent 0. Each of c and d preferably independently represents an integer of 1 or more and 5 or less, and more preferably 2.

The bonding position of R ^{20 to} R ²³ is not particularly limited. R ^{20 to} R ²³ may be bonded (positioned) at any of the ortho, meta and para positions of the phenyl group. R ²² and R ²³ are each preferably bonded to the ortho position of the phenyl group.

In the general formula (4), e and f each independently represent an integer of 0 or more and 4 or less. When e represents an integer of 2 or more and 4 or less, a plurality of R ²⁴ bonded to the same phenylene group may be the same or different. When f represents an integer of 2 or more and 4 or less, a plurality of R ²⁵ bonded to the same phenylene group may be the same or different. Preferably, e and f each represent 0.

The bonding position of R ²⁴ and R ²⁵ is not particularly limited. Each of R ²⁴ and R ²⁵ may be bonded (positioned) to either the ortho position or the meta position with respect to the nitrogen atom to which the phenylene group is bonded.

  A specific example of the compound (4) is a compound represented by the following chemical formula (4-1) (hereinafter, sometimes described as a compound (4-1)).

  When the photosensitive layer contains the compound (3) as a hole transport agent, the content of the compound (3) is preferably 80% by mass or more, and 90% by mass, based on the total mass of the hole transport agent. It is more preferable that it is the above, and it is especially preferable that it is 100 mass%.

  When the photosensitive layer contains the compound (4) as a hole transport agent, the content of the compound (4) is preferably 80% by mass or more, and 90% by mass, based on the total mass of the hole transport agent. It is more preferable that it is the above, and it is especially preferable that it is 100 mass%.

  The content of the hole transfer agent contained in the photosensitive layer is preferably 40 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the binder resin contained in the photosensitive layer.

(Charge generating agent)
The photosensitive layer contains a charge generating agent. The charge generating agent is not particularly limited as long as it is a charge generating agent for a photoreceptor. Examples of charge generating agents include phthalocyanine pigments, perylene pigments, bisazo pigments, trisazo pigments, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squalene pigments, indigo pigments, azulenium pigments, cyanines Pigment, powder of inorganic photoconductive material (eg, selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide or amorphous silicon), pyrylium pigment, ansanthrone pigment, triphenylmethane pigment, selenium pigment, toluidine pigment, A pyrazoline pigment or a quinacridone pigment is mentioned. One type of charge generating agent may be used alone, or two or more types may be used in combination.

  Examples of phthalocyanine pigments include metal-free phthalocyanines or metal phthalocyanines represented by the chemical formula (CGM-1). Examples of metal phthalocyanines include titanyl phthalocyanine, hydroxygallium phthalocyanine and chlorogallium phthalocyanine. The phthalocyanine pigment may be crystalline or non-crystalline. The crystal form (for example, α-type, β-type, Y-type, V-type or II-type) of the phthalocyanine-based pigment is not particularly limited, and phthalocyanine-based pigments having various crystal forms are used.

  Examples of crystals of metal-free phthalocyanine include, for example, X-type crystals of metal-free phthalocyanine (hereinafter sometimes referred to as X-type metal-free phthalocyanine). Examples of crystals of titanyl phthalocyanine include α-type, β-type or Y-type crystals of titanyl phthalocyanine (hereinafter sometimes referred to as α-type, β-type or Y-type titanyl phthalocyanine). Examples of hydroxygallium phthalocyanine crystals include V-type crystals of hydroxygallium phthalocyanine. Examples of chlorogallium phthalocyanine crystals include type II crystals of chlorogallium phthalocyanine.

  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 photosensitive member having sensitivity in a wavelength region of 700 nm or more. As a charge generating agent, phthalocyanine pigments are preferable, metal-free phthalocyanines or titanyl phthalocyanines are more preferable, and X-type metal-free phthalocyanines or Y-type titanyl phthalocyanines are more preferable because they have high quantum yield in a wavelength region of 700 nm or more. And X-type metal free phthalocyanines are particularly preferred.

  For a photosensitive member applied to an image forming apparatus using a short wavelength laser light source (for example, a laser light source having a wavelength of 350 nm to 550 nm), an anthanthrone pigment is suitably used as a charge generating agent.

  The content of the charge generating agent is preferably 0.1 parts by mass to 50 parts by mass, and more preferably 1 part by mass to 30 parts by mass with respect to 100 parts by mass of the binder resin contained in the photosensitive layer. Is more preferred.

(Additive)
The photosensitive layer may contain various additives as needed. As the additive, for example, an antidegradant (for example, an antioxidant, a radical scavenger, a singlet quencher or an ultraviolet absorber), a softener, a surface modifier, an extender, a thickener, a dispersion stabilizer Waxes, acceptors, donors, surfactants, plasticizers, sensitizers or leveling agents. Examples of antioxidants include hindered phenols (eg, di (tert-butyl) p-cresol), hindered amines, paraphenylenediamines, arylalkanes, hydroquinones, spirochromans, spiroindanones or derivatives thereof, organic sulfur compounds or Organophosphorus compounds are mentioned.

<1-2. Conductive substrate>
The conductive substrate is not particularly limited as long as it can be used as the conductive substrate of the photoreceptor. The conductive substrate may be formed at least at a surface portion of a material having conductivity. An example of the conductive substrate is a conductive substrate formed of a conductive material. Another example of the conductive substrate is a conductive substrate coated with a material having conductivity. As the material having conductivity, for example, aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel or brass can be mentioned. These materials having conductivity may be used alone, or two or more may be used in combination (for example, as an alloy). Among these materials having conductivity, aluminum or an aluminum alloy is preferable because charge transfer from the photosensitive layer to the conductive substrate is good.

  The shape of the conductive substrate is appropriately selected in accordance with the structure of the image forming apparatus. Examples of the shape of the conductive substrate include a sheet or a drum. In addition, the thickness of the conductive substrate is appropriately selected according to the shape of the conductive substrate.

<1-3. Middle layer>
The intermediate layer (undercoat layer) contains, for example, inorganic particles and a resin (interlayer resin) used for the intermediate layer. By the presence of the intermediate layer, it is considered that the flow of current generated when the photosensitive member is exposed can be smoothed and the increase in resistance can be suppressed while maintaining the insulation state to the extent that the occurrence of leakage can be suppressed.

  As the inorganic particles, for example, particles of metal (for example, aluminum, iron or copper), metal oxide (for example, titanium oxide, alumina, zirconium oxide, tin oxide or zinc oxide) or non-metal oxide (for example, silica) Particles of One of these inorganic particles may be used alone, or two or more thereof 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 the additives of the photosensitive layer.

<1-4. Method of manufacturing photoreceptor>
The photoreceptor is manufactured, for example, as follows. The photoreceptor is manufactured by applying a coating solution for a photosensitive layer on a conductive substrate and drying it. The coating solution for the photosensitive layer is produced by dissolving or dispersing the charge generating agent, the electron transfer agent, the hole transfer agent, the binder resin and the components (eg, various additives) added as necessary in a solvent. Ru.

  The solvent contained in the coating solution for the photosensitive layer is not particularly limited as long as it can dissolve or disperse each component contained in the coating solution. Examples of solvents include alcohols (eg methanol, ethanol, isopropanol or butanol), aliphatic hydrocarbons (eg n-hexane, octane or cyclohexane), aromatic hydrocarbons (eg benzene, toluene or xylene), Halogenated hydrocarbons (for example, dichloromethane, dichloroethane, carbon tetrachloride or chlorobenzene), ethers (for example, dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether or propylene glycol monomethyl ether), ketones (for example, acetone, Methyl ethyl ketone or cyclohexanone), esters (eg ethyl acetate or methyl acetate), dimethyl formaldehyde, Amide or dimethyl sulfoxide. These solvents are used singly or in combination of two or more. In order to improve the workability at the time of production of the photosensitive member, it is preferable to use a non-halogen solvent (a solvent other than a halogenated hydrocarbon) as the solvent.

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

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

  The method for applying the coating solution for the photosensitive layer is not particularly limited as long as it is a method capable of uniformly applying the coating solution on the conductive substrate. As a coating method, a dip coating method, a spray coating method, a spin coating method, or a bar coating method is mentioned, for example.

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

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

<2. Image forming apparatus>
Next, with reference to FIG. 3, an image forming apparatus 100 including the photosensitive member 1 according to the present embodiment will be described. An example of the configuration of the image forming apparatus 100 is shown in 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 system. Hereinafter, the tandem type image forming apparatus 100 will be described as an example.

  The image forming apparatus 100 includes image forming units 40 a, 40 b, 40 c and 40 d, a transfer belt 50, and a fixing unit 52. Hereinafter, each of the image forming units 40 a, 40 b, 40 c, and 40 d will be referred to as an image forming unit 40 if it is not necessary to distinguish.

  The image forming unit 40 includes the photosensitive member 1, a charging unit 42, an exposure unit 44, a developing unit 46, and a transfer unit 48. The photosensitive member 1 is provided at the center position of the image forming unit 40. The photosensitive member 1 is provided rotatably in the arrow direction (counterclockwise). The charging unit 42, the exposure unit 44, the developing unit 46, and the transfer unit 48 are provided around the photosensitive member 1 in order from the upstream side of the rotational direction of the photosensitive member 1 with respect to the charging unit 42. The image forming unit 40 may further include one or both of a cleaning unit (not shown) and a charge removing unit (not shown). The cleaning unit and the charge removal unit are provided, for example, between the transfer unit 48 and the charging unit 42.

  The charging unit 42 charges the surface of the photosensitive member 1. The charging unit 42 is a noncontact system or a contact system. An example of the non-contact charging unit 42 is a corotron charger or a scorotron charger. An example of the contact type charging unit 42 is a charging roller or a charging brush.

  The image forming apparatus 100 can include a charging roller as the charging unit 42. When the surface of the photosensitive member 1 is charged, the charging roller contacts the photosensitive member 1. When a minute component (for example, paper powder) of a recording medium P (for example, paper) adheres to the surface of the photosensitive member 1, the minute component is pressed against the surface of the photosensitive member 1 by the charging roller in contact. As a result, minute components are easily fixed to the surface of the photosensitive member 1. However, the image forming apparatus 100 includes the photosensitive member 1 capable of suppressing the occurrence of white spots caused by the adhesion of the minute component. For this reason, even when the image forming apparatus 100 includes the charging roller as the charging unit 42, it is difficult for the minute component to be fixed to the surface of the photosensitive member 1 and to suppress the generation of white spots in the formed image. it can.

  The charging unit 42 preferably charges the surface of the photosensitive member 1 to a positive polarity. When the photosensitive member 1 of the present embodiment and the recording medium P come into contact with each other and are rubbed, the recording medium P tends to be positively charged. When the surface of the photosensitive member 1 is positively charged by the charging unit 42, the surface of the photosensitive member 1 and the recording medium P frictionally charged to the positive polarity electrically repel each other. As a result, minute components (for example, paper dust) of the recording medium P do not easily adhere to the surface of the photosensitive member 1, and the generation of white spots in the formed image can be suitably suppressed.

  The exposure unit 44 exposes the charged surface of the photosensitive member 1. Thereby, an electrostatic latent image is formed on the surface of the photosensitive member 1. The electrostatic latent image is formed based on the image data input to the image forming apparatus 100.

  The developing unit 46 supplies toner to the electrostatic latent image formed on the photosensitive member 1. Thereby, the electrostatic latent image is developed as a toner image. The photosensitive member 1 corresponds to an image carrier that carries a toner image.

  The developing unit 46 can develop the electrostatic latent image as a toner image while being in contact with the photosensitive member 1. That is, the image forming apparatus 100 can adopt a so-called contact development method. When a minute component (for example, paper dust) of the recording medium P adheres to the surface of the photosensitive member 1, the minute component is pressed against the surface of the photosensitive member 1 by the developing unit 46 in contact. As a result, minute components are easily fixed to the surface of the photosensitive member 1. However, the image forming apparatus 100 includes the photosensitive member 1 capable of suppressing the occurrence of white spots caused by the adhesion of the minute component. Therefore, even when the contact developing method is adopted, the image forming apparatus 100 can not easily fix the minute components to the surface of the photosensitive member 1 and can suppress the generation of white spots in the formed image.

  The developing unit 46 can clean the surface of the photosensitive member 1. That is, the image forming apparatus 100 can adopt a so-called cleanerless system. The developing unit 46 can remove components remaining on the surface of the photosensitive member 1 (hereinafter, sometimes referred to as “residual components”). An example of the residual component is a toner component, more specifically, a toner or a free external additive. Another example of the residual component is a non-toner component, more specifically, a minute component of the recording medium P (for example, paper powder). In the image forming apparatus 100 adopting the cleanerless method, residual components on the surface of the photosensitive member 1 are not scraped off by the cleaning unit (for example, a cleaning blade). Therefore, in the image forming apparatus 100 adopting the cleanerless method, residual components are likely to remain on the surface of the photosensitive member 1 in general. However, the photosensitive member 1 of the present embodiment can suppress the generation of white spots caused by the adhesion of the minute component. Therefore, even if the image forming apparatus 100 including such a photosensitive member 1 adopts the cleanerless method, residual components, particularly minute components (for example, paper dust) of the recording medium P are hardly left on the surface of the photosensitive member 1. . As a result, the image forming apparatus 100 can suppress the occurrence of white spots in the formed image.

In order for the developing unit 46 to clean the surface of the photosensitive member 1 efficiently, it is preferable that the following conditions (a) and (b) be satisfied.
Condition (a): A contact development method is adopted, and a circumferential speed (rotational speed) difference is provided between the photosensitive member 1 and the developing unit 46.
Condition (b): The surface potential of the photosensitive member 1 and the potential of the developing bias satisfy the following mathematical expressions (b-1) and (b-2).
0 (V) <potential of developing bias (V) <surface potential of unexposed area of photoreceptor 1 (V) (b-1)
Potential of development bias (V)> surface potential of exposed area of photoreceptor 1 (V)> 0 (V) (B-2)

  If the contact developing method shown in the condition (a) is adopted and the peripheral speed difference is provided between the photosensitive member 1 and the developing unit 46, the surface of the photosensitive member 1 contacts the developing unit 46, and the photosensitive member 1 is The adhered components on the surface of the toner are removed by friction with the developing unit 46. The circumferential speed of the developing unit 46 is preferably faster than the circumferential speed of the photosensitive member 1.

  In the condition (b), it is assumed that the developing method is the reverse developing method. In order to improve the electrical characteristics of the photosensitive member 1 which is a single layer type photosensitive member, the charging polarity of the toner, the surface potential of the unexposed region of the photosensitive member 1, the surface potential of the exposed region of the photosensitive member 1 and the potential of the developing bias Is preferably positive. The surface potential of the unexposed area of the photosensitive member 1 and the surface potential of the exposed area of the photosensitive member 1 after the transfer unit 48 transfers the toner image from the photosensitive member 1 to the recording medium P It is measured before charging the surface.

  When the numerical formula (b-1) of the condition (b) is satisfied, electrostatic acting between the toner remaining on the photosensitive member 1 (hereinafter sometimes referred to as residual toner) and the unexposed area of the photosensitive member 1 The potential repulsive force is larger than the electrostatic repulsive force acting between the residual toner and the developing portion 46. Therefore, the residual toner in the unexposed area of the photosensitive member 1 moves from the surface of the photosensitive member 1 to the developing unit 46 and is collected.

  When the numerical formula (b-2) of the condition (b) is satisfied, the electrostatic repulsion acting between the residual toner and the exposure area of the photosensitive member 1 acts on the electrostatic between the residual toner and the developing portion 46 It becomes smaller than the repulsive force. Therefore, the residual toner in the exposed area of the photosensitive member 1 is held on the surface of the photosensitive member 1. The toner held in the exposure area of the photosensitive member 1 is used as it is for image formation.

  The transfer belt 50 conveys the recording medium P between the photosensitive member 1 and the transfer unit 48. The transfer belt 50 is an endless belt. The transfer belt 50 is provided rotatably in the arrow direction (clockwise).

  The transfer unit 48 transfers the toner image developed by the developing unit 46 from the photosensitive member 1 to the recording medium P. When the toner image is transferred from the photosensitive element 1 to the recording medium P by the transfer unit 48, the photosensitive element 1 is in contact with the recording medium P. That is, the image forming apparatus 100 adopts a so-called direct transfer method. The transfer unit 48 is, for example, a transfer roller.

  The 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 by each of the image forming units 40a to 40d. 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 fixing unit 52 heats and / or pressurizes the unfixed toner image transferred to the recording medium P by the transfer unit 48. The fixing unit 52 is, for example, a heating roller and / or a pressure roller. The toner image is fixed on the recording medium P by heating and / or pressurizing the toner image. As a result, an image is formed on the recording medium P.

<3. Process cartridge>
Next, with continued reference to FIG. 3, the process cartridge provided with the photosensitive member 1 of the present embodiment will be described. The process cartridge corresponds to each of the image forming units 40a to 40d. The process cartridge includes the photosensitive member 1 unitized. 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, and a transfer unit 48 in addition to the photosensitive member 1 is unitized. The process cartridge may further include one or both of a cleaning device (not shown) and a static eliminator (not shown). The process cartridge is designed to be removable from the image forming apparatus 100. Therefore, the process cartridge is easy to handle, and can be easily and quickly replaced including the photosensitive member 1 when the sensitivity characteristics and the like of the photosensitive member 1 are deteriorated.

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

<1. Material of Photoreceptor>
As materials for forming the photosensitive layer of the photosensitive member, the following binder resin, charge generating agent, hole transporting agent and electron transporting agent were prepared.

<1-1. Binder resin>
The polycarbonate resins (1-1) to (1-4) described in the embodiments were prepared as binder resins. The viscosity average molecular weight of polycarbonate resin (1-1)-(1-4) was 50000.

  Polycarbonate resins (1-5) to (1-7) were prepared as binder resins for comparison. Each of polycarbonate resin (1-5)-(1-7) is represented by following Chemical formula (1-5)-(1-7). The viscosity average molecular weight of polycarbonate resin (1-5)-(1-7) was 50000. In addition, the subscript attached | subjected to the repeating unit in Chemical formula (1-5)-(1-7) represents the molar ratio of each repeating unit. The subscript “1.0” in the chemical formulas (1-5) and (1-7) is a repeating unit in which each of the polycarbonate resins (1-5) and (1-7) is subscripted Indicates that it consists only of

<1-2. Charge generator>
An X-type metal free phthalocyanine was prepared as a charge generating agent.

<1-3. Hole transport agent>
Compounds (3-1) and (4-1) described in the embodiment were prepared as hole transport agents.

<1-4. Electron transport agent>
The compounds (2-1), (2-5), and (2-10) described in the embodiments were prepared as electron transport agents. Specifically, compounds (2-1), (2-5) and (2-10) were synthesized by the following method.

(Production of Compound (2-1))
Compound (2-1) was produced according to the following reactions (R-3) and (R-4). The compounds represented by the chemical formulas (A-1), (B-1), (C-1) and (D) in the following reaction formulas are respectively compounds (A-1), (B-1), (D) It may be described as C-1) and (D).

  In the reaction (R-3), the compound (A-1) and the compound (B-1) were reacted to obtain a compound (C-1). Specifically, 2.24 g (0.010 mol) of compound (A-1), 3.26 g (0.030 mol) of compound (B-1) and toluene (100 mL) are added to a flask, and the contents of the flask are It was dissolved. Into the flask was added p-toluenesulfonic acid (0.001 mol). The flask was set in the Dean-Stark apparatus. The contents of the flask were refluxed for dehydration at 90 ° C. for 5 hours. The contents of the resulting flask were depressurized and the toluene was distilled off. Ion-exchanged water was added to the mixture after evaporation under reduced pressure, and the mixture was extracted with chloroform. After drying the obtained organic layer, the organic layer was depressurized and chloroform was distilled off. As a result, compound (C-1) was obtained as a crude product. The yield of compound (C-1) was 2.84 g, and the yield of compound (C-1) from compound (A-1) was 90 mol%.

  In the reaction (R-4), the compound (C-1) and the compound (D, malononitrile) were reacted to obtain a compound (2-1). Specifically, 1.57 g (0.005 mol) of compound (C-1) and 0.66 g (0.010 mol) of compound (D) were added to methanol (100 mL) to obtain a methanol solution. To a methanol solution was added 0.08 g (0.001 mol) of piperidine to obtain a mixture. The mixture was stirred at 80 ° C. for 3 hours while refluxing. Subsequently, the mixture was added to ion-exchanged water (200 mL) to precipitate a solid, and the solid was collected by filtration. The obtained solid was purified by silica gel column chromatography using chloroform as a developing solvent. As a result, compound (2-1) was obtained. The yield of compound (2-1) was 1.45 g, and the yield of compound (2-1) from compound (C-1) was 80 mol%.

(Production of Compound (2-5))
Reaction (R-3) was carried out in the same manner as in the production of compound (C-1) except for the following changes. 3.26 g (0.030 mol) of compounds (B-1) added by manufacture of a compound (C-1) was changed into 5.31 g (0.030 mol) of compounds (B-5). As a result, compound (C-5) was obtained instead of compound (C-1). The yield of compound (C-5) was 3.26 g, and the yield of compound (C-5) from compound (A-1) was 85 mol%. The compounds (B-5) and (C-5) are compounds represented by the following chemical formulas (B-5) and (C-5), respectively.

  Subsequently, a reaction (R-4) was performed in the same manner as in the production of the compound (2-1) except that the following points were changed. 1.57 g (0.005 mol) of compound (C-1) added in the production of compound (2-1) was changed to 1.92 g (0.005 mol) of compound (C-5). As a result, compound (2-5) was obtained instead of compound (2-1). The yield of compound (2-5) was 1.73 g, and the yield of compound (2-5) from compound (C-5) was 80 mol%.

(Production of Compound (2-10))
Reaction (R-3) was carried out in the same manner as in the production of compound (C-1) except for the following changes. 2.24 g (0.010 mol) of compound (A-1) added in the production of compound (C-1) was changed to 2.24 g (0.010 mol) of compound (A-10). 3.26 g (0.030 mol) of compounds (B-1) added by manufacture of a compound (C-1) was changed into 3.84 g (0.030 mol) of compounds (B-10). As a result, compound (C-10) was obtained instead of compound (C-1). The yield of compound (C-10) was 2.81 g, and the yield of compound (C-10) from compound (A-1) was 84 mol%. The compounds (A-10), (B-10) and (C-10) are compounds represented by the following chemical formulas (A-10), (B-10) and (C-10), respectively.

  Subsequently, a reaction (R-4) was performed in the same manner as in the production of the compound (2-1) except that the following points were changed. 1.57 g (0.005 mol) of compound (C-1) added in the production of compound (2-1) was changed to 1.67 g (0.005 mol) of compound (C-10). As a result, compound (2-10) was obtained instead of compound (2-1). The yield of compound (2-10) was 1.76 g, and the yield of compound (2-10) from compound (C-10) was 92 mol%.

Next, with reference to ¹ H-NMR (proton nuclear magnetic resonance spectroscopy), it was analyzed by ¹ H-NMR spectrum of the compound prepared (2-1). The magnetic field strength was set to 300 MHz. Deuterated chloroform (CDCl ₃ ) was used as a solvent. Tetramethylsilane (TMS) was used as an internal standard substance. The chemical shift values of the ¹ H-NMR spectrum of compound (2-1) are shown below. It was confirmed from the chemical shift value of the measured ¹ H-NMR spectrum that the compound (2-1) was obtained. In addition, similarly to the compounds (2-5) and (2-10), it was confirmed that the compounds (2-5) and (2-10) were obtained.

Compound (2-1): ¹ H-NMR (300 MHz, CDCl ₃ ) δ = 8.53 (dd, 1 H), 8.39 (d, 1 H), 8.18 (d, 1 H), 7.85 ( dd, 1 H), 7.49 (dt, 1 H), 7. 35 (t, 1 H), 7.3 4 (dt, 1 H), 4. 45 (t, 2 H), 3.63 (t, 2 H), 1.90-2.07 (m, 4H).

  Preparation of compounds represented by the following chemical formulas (2-11) and (2-12) (hereinafter sometimes referred to as compounds (2-11) and (2-12)) as electron transport agents for comparison did.

<2. Production of photoconductor>
Photosensitive members (P-1) to (P-19) were manufactured using materials for forming a photosensitive layer.

<2-1. Production of Photoreceptor (P-1)>
In a container, 2 parts by mass of X-type metal-free phthalocyanine as charge generating agent, 55 parts by mass of compound (3-1) as hole transporting agent, 35 parts by mass of compound (2-1) as electron transporting agent, binder 100 parts by mass of polycarbonate resin (1-1) as a resin and 700 parts by mass of tetrahydrofuran as a solvent were charged. The contents of the container were mixed using a ball mill for 12 hours to disperse the materials in the solvent. Thus, a coating solution for photosensitive layer was obtained. The coating solution for a photosensitive layer was applied on an aluminum drum-shaped support (diameter 30 mm, total length 238.5 mm) as a conductive substrate using a dip coating method. The coating solution for photosensitive layer applied was dried with hot air at 120 ° C. for 80 minutes. Thereby, a photosensitive layer (film thickness of 30 μm) was formed on the conductive substrate. As a result, a photoreceptor (P-1) was obtained.

2-2. Production of Photoreceptors (P-2) to (P-19)>
Photosensitive members (P-2) to (P-19) were produced in the same manner as in the production of photosensitive member (P-1), except that the following points were changed. The polycarbonate resin (1-1) as a binder resin used for the production of the photosensitive member (P-1) was changed to a binder resin of the type shown in Table 1. The compound (2-1) as the electron transfer agent used for the production of the photosensitive member (P-1) was changed to an electron transfer agent of the type shown in Table 1. The compound (3-1) as a hole transfer agent used in the production of the photosensitive member (P-1) was changed to a hole transfer agent of the type shown in Table 1.

<3. Evaluation of electrical characteristics>
The electrical characteristics of each of the manufactured photosensitive members (P-1) to (P-19) were evaluated. The evaluation of the electrical characteristics was performed under an environment of a temperature of 23 ° C. and a relative humidity of 50% RH. First, the surface of the photosensitive member was charged to +600 V using a drum sensitivity tester (manufactured by Gentec Co., Ltd.). Next, monochromatic light (wavelength 780 nm, half width 20 nm, light energy 1.5 μJ / cm ² ) was extracted from white light of the halogen lamp using a band pass filter. The extracted monochromatic light was irradiated to the surface of the photoreceptor. The surface potential of the photosensitive member was measured 0.5 seconds after the end of the irradiation. The measured surface potential was taken as the sensitivity potential (V _L , unit: + V). The measured sensitivity potentials (V _L ) of the photosensitive members are shown in Table 1. The smaller the absolute value of the sensitivity potential (V _L ), the better the electrical characteristics of the photosensitive member.

<4. Evaluation of triboelectricity>
The triboelectric chargeability was evaluated for each of the manufactured photosensitive members (P-1) to (P-19).

  Hereinafter, with reference to FIG. 2 again, a method of measuring the charge amount of calcium carbonate when the photosensitive layer 3 and the calcium carbonate are rubbed will be described. The charge amount of calcium carbonate was measured by performing the following first step, second step, third step and fourth step. The jig 10 was used to measure the charge amount of calcium carbonate.

  The jig 10 includes a first base 12, a rotary shaft 14, a rotary drive unit 16 (for example, a motor), and a second base 18. The rotation drive unit 16 rotates the rotation shaft 14. The rotating shaft 14 rotates around the rotation axis S of the rotating shaft 14. The first stand 12 is integral with the rotating shaft 14 and rotates about the rotation axis S. The second stand 18 is fixed without rotating.

(First step)
In the first step, two photosensitive layers 3 were prepared. Hereinafter, one of the photosensitive layers 3 is referred to as a first photosensitive layer 30, and the other of the photosensitive layers 3 is referred to as a second photosensitive layer 32. First, the first film 20 provided with the first photosensitive layer 30 having a film thickness L1 of 30 μm was prepared. In addition, a second film 22 provided with a second photosensitive layer 32 having a film thickness L2 of 30 μm was prepared. In detail, overhead projector (OHP) films were used as the first film 20 and the second film 22. The size of each of the first film 20 and the second film 22 was a circle having a diameter of 3 cm. On each of the first film 20 and the second film 22, the coating solution for a photosensitive layer used in the production of the photosensitive member (P-1) was applied. The coating solution for photosensitive layer applied was dried with hot air at 120 ° C. for 80 minutes. As a result, the first film 20 including the first photosensitive layer 30 and the second film 22 including the second photosensitive layer 32 were obtained.

(Second step)
In the second step, 0.007 g of calcium carbonate was placed on the first photosensitive layer 30. Thus, a calcium carbonate layer 24 composed of calcium carbonate was formed on the first photosensitive layer 30. Then, the second photosensitive layer 32 was placed on the calcium carbonate layer 24. The specific procedure of the second step was as follows.

  First, the first film 20 was fixed to the first base 12 using a double-sided tape. 0.007 g of calcium carbonate was placed on the first photosensitive layer 30 of the first film 20. Thus, a calcium carbonate layer 24 composed of calcium carbonate was formed on the first photosensitive layer 30. The second film 22 was fixed to the second pedestal 18 using a double-sided tape so that the calcium carbonate layer 24 was in contact with the second photosensitive layer 32. Thus, the first table 12, the first film 20, the first photosensitive layer 30, the calcium carbonate layer 24, the second photosensitive layer 32, the second film 22, and the second table 18 are disposed in order from the bottom. The centers of the first table 12, the first film 20, the first photosensitive layer 30, the second photosensitive layer 32, the second film 22 and the second table 18 are disposed to pass through the rotation axis S.

(Third step)
In the third step, while the second photosensitive layer 32 is fixed, the first photosensitive layer 30 is rotated at a rotational speed of 60 rpm for 60 seconds under an environment of a temperature of 23 ° C. and a relative humidity of 50% RH. Specifically, the rotary drive unit 16 is driven to rotate the rotary shaft 14, the first base 12, the first film 20 and the first photosensitive layer 30 about the rotation axis S at a rotation speed of 60 rpm for 60 seconds. The Thereby, the calcium carbonate contained in the calcium carbonate layer 24 is rubbed between the first photosensitive layer 30 and the second photosensitive layer 32, and the calcium carbonate is charged.

(4th step)
In the fourth step, calcium carbonate charged in the third step was taken out from the jig 10 and was suctioned using a charge amount measuring device (a suction type small charge amount measuring device, "Model 212 HS" manufactured by Trek Co.). The total electric quantity Q (unit: + μC) and mass M (unit: g) of the sucked calcium carbonate were measured using a charge amount measuring device. From the formula “charge amount = Q / M”, the charge amount (frictional charge amount, unit: + μC / g) of calcium carbonate was calculated.

  The triboelectric chargeability of each of the photoreceptors (P-2) to (P-19) was evaluated by the same method as the triboelectric charge evaluation of the photoreceptor (P-1) except that the following points were changed. . In the first step, instead of the coating solution for the photosensitive layer used for the production of the photosensitive member (P-1), the coating solution for the photosensitive layer used for the production of the photosensitive members (P-2) to (P-19) I used each.

  The calculated charge amount of calcium carbonate is shown in Table 1 for each of the photosensitive members (P-1) to (P-19). The larger the positive charge amount of calcium carbonate, the more easily the calcium carbonate is charged to the positive polarity with respect to the first photosensitive layer 30 and the second photosensitive layer 32.

<5. Evaluation of image characteristics>
Image characteristics were evaluated for each of the manufactured photoreceptors (P-1) to (P-19). The evaluation of the image characteristics was performed under the environment of temperature 32.5 ° C. and relative humidity 80% RH. As an evaluation machine, an image forming apparatus (a modified machine of "monochrome printer FS-1300D" manufactured by KYOCERA Document Solutions Inc.) was used. Specifically, the non-contact development system was converted to a contact development system. The blade cleaning method has been converted to a cleanerless method. The scorotron charger was converted to a charging roller. The image forming apparatus adopts a direct transfer method, and the charging polarity of the charging portion is positive. As a recording medium, "Kyocera Document Solutions brand paper VM-A4" (A4 size) sold by KYOCERA Document Solutions Inc. was used. For the evaluation by the evaluation machine, a one-component developer (prototype) was used.

  The image I (image with 1% printing rate) was continuously printed on 20000 sheets of recording medium under the condition of the rotational speed of the photosensitive member of 168 mm / sec using the evaluation machine. Subsequently, the image II (A4 size black solid image) was printed on one recording medium. The recording medium on which the image II was formed was observed with the naked eye, and the number of white spots appearing in the image II was counted. As the minute components (for example, paper dust) of the recording medium adhere to the photosensitive member, the number of white spots in the image II tends to increase. The number of white spots appearing in the image II is shown in Table 1.

In Table 1, HTM, ETM and _VL respectively indicate a hole transfer agent, an electron transfer agent and a sensitivity potential.

  The photosensitive layers of the photosensitive members (P-1) to (P-12) and (P-18) were single-layered photosensitive layers containing a charge generating agent, an electron transferring agent, a hole transferring agent and a binder resin. . The binder resin contained polycarbonate resin (1), specifically polycarbonate resin (1-1), (1-2), (1-3) or (1-4). The electron transfer agent contained the compound (2), specifically the compound (2-1), (2-5) or (2-10). Therefore, as apparent from Table 1, in the photosensitive members (P-1) to (P-12) and (P-18), the number of white spots in the formed image is small, and the generation of the white spots is suppressed. . Further, with these photosensitive members, the generation of white spots in the formed image could be suppressed without impairing the electrical characteristics of the photosensitive members.

  On the other hand, the photosensitive layers of the photosensitive members (P-13) to (P-15) did not contain the polycarbonate resin (1) and the compound (2). The photosensitive layer of the photoreceptor (P-16) did not contain the compound (2). The photosensitive layer of the photoreceptor (P-17) did not contain the polycarbonate resin (1). The photosensitive layer of the photoreceptor (P-19) did not contain the compound (2). Therefore, as is clear from Table 1, in the photosensitive members (P-13) to (P-17) and (P-19), the number of white spots in the formed image was large, and white spots occurred.

  From the above, it has been shown that the photoreceptor according to the present invention suppresses the occurrence of white spots in the formed image. In addition, it has been shown that the process cartridge and the image forming apparatus according to the present invention suppress the generation of white spots in the formed image.

  The photoreceptor according to the present invention can be used in an image forming apparatus. The process cartridge and the image forming apparatus according to the present invention can be used to form an image on a recording medium.

Reference Signs List 1 electrophotographic photosensitive member 2 conductive substrate 3 photosensitive layer 42 charging unit 44 exposure unit 46 developing unit 48 transfer unit 100 image forming apparatus P recording medium

Claims (14)

An electrophotographic photosensitive member comprising a conductive substrate and a photosensitive layer,
The photosensitive layer is a single layer, and the photosensitive layer contains a charge generating agent, an electron transporting agent, a hole transporting agent, and a binder resin.
The binder resin includes a polycarbonate resin represented by the following general formula (1),
The electrophotographic photosensitive member, wherein the electron transfer agent contains a compound represented by the following general formula (2).

In the general formula (1),
Each of R ¹ , R ² , R ⁵ and R ⁶ independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms having one or more halogen atoms, or a carbon atom having 1 or more halogen atoms. Alkoxy group having 6 or less, an aryl group having 6 to 14 carbon atoms having one or more halogen atoms, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms or Represents an aryl group having 6 to 14 carbon atoms,
At least one of R ¹ , R ² , R ⁵ and R ⁶ is a halogen atom, an alkyl group having 1 or more and 6 or less carbon atoms having one or more halogen atoms, or a carbon atom having one or more halogen atoms 1 or more and 6 or less alkoxy groups or an aryl group having 6 or more and 14 or less carbon atoms having one or more halogen atoms,
Each of R ³ and R ⁴ independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or 1 to 6 carbon atoms which may have a substituent. The following alkoxy group or an aryl group having 6 to 14 carbon atoms which may have a substituent,
Y has a single bond, an alkylene group having 2 to 18 carbon atoms which may have a substituent, an alkylidene group having 1 to 18 carbon atoms which may have a substituent, a substituent Optionally substituted cycloalkyl group having 5 to 15 carbon atoms, optionally substituted cycloalkyl group having 5 to 15 carbon atoms, -S-, -SO-, -O- or Represents -CO-,
Each of m and n independently represents a number satisfying the following formulas (i) and (ii).
m + n = 1.0 (i)
0.0 <m ≦ 1.0 (ii)

In the general formula (2), R ⁷ is
An alkyl group having 1 to 8 carbon atoms and having one or more halogen atoms,
A cycloalkyl group having one or more halogen atoms and having 3 to 10 carbon atoms,
An aryl group having 6 to 14 carbon atoms, which has one or more halogen atoms and may have an alkyl group having 1 to 6 carbon atoms,
And a 5- to 14-membered heterocyclic group having one or more halogen atoms, or an aralkyl group having 7 to 20 carbon atoms having one or more halogen atoms.   The electrophotographic photosensitive member according to claim 1, wherein the charge amount of the calcium carbonate when the photosensitive layer and the calcium carbonate are rubbed is 7.0 μC / g or more.   3. The electrophotographic photosensitive member according to claim 1, wherein the charge amount of the calcium carbonate when the photosensitive layer and the calcium carbonate are rubbed is not less than 9.0 μC / g and not more than 15.0 μC / g. In the general formula (1),
R ¹ , R ² , R ⁵ and R ⁶ each independently represent a halogen atom, an alkyl group having 1 or more and 6 or less carbon atoms having one or more halogen atoms, or 6 carbon atoms having one or more halogen atoms Represents an aryl group having 14 or more and a hydrogen atom or an alkyl group having 1 to 6 carbon atoms,
At least one of R ¹ , R ² , R ⁵ and R ⁶ is a halogen atom, C 1 to 6 carbon atoms having one or more halogen atoms, or C 1 to 6 carbon atoms having one or more halogen atoms Represents an aryl group of 6 or more and 14 or less,
R ³ and R ⁴ each represent a hydrogen atom,
The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein Y represents a cycloalkylidene group having 5 to 15 carbon atoms. The polycarbonate resin represented by the general formula (1) is a polycarbonate resin represented by the following chemical formula (1-1), (1-2), (1-3) or (1-4). The electrophotographic photosensitive member according to any one of 1 to 4.

In the general formula (2), R ⁷ is
The compound according to any one of claims 1 to 5, which represents an alkyl group having 1 to 8 carbon atoms having one or two halogen atoms, or an aralkyl group having 7 to 20 carbon atoms having one or two halogen atoms. An electrophotographic photosensitive member according to any one of the preceding claims. The electrophotographic photosensitive member according to any one of claims 1 to 6, wherein the hole transfer agent contains a compound represented by the following general formula (3).

In the general formula (3), R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ are each independently. And a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. In the general formula (3), R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ are each independently. The electrophotographic photosensitive member according to claim 7, which represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.   A process cartridge comprising the electrophotographic photosensitive member according to any one of claims 1 to 8. An image forming apparatus comprising the electrophotographic photosensitive member according to any one of claims 1 to 8, a charging unit, an exposure unit, a developing unit, and a transfer unit,
The charging unit charges the surface of the electrophotographic photosensitive member,
The exposure unit exposes the charged surface of the electrophotographic photosensitive member to form an electrostatic latent image on the surface of the electrophotographic photosensitive member.
The developing unit develops the electrostatic latent image as a toner image,
The transfer unit transfers the toner image from the electrophotographic photosensitive member to a recording medium,
The image forming apparatus, wherein the electrophotographic photosensitive member is in contact with the recording medium when the transfer unit transfers the toner image from the electrophotographic photosensitive member to the recording medium.   The image forming apparatus according to claim 10, wherein the developing unit develops the electrostatic latent image as the toner image while being in contact with the electrophotographic photosensitive member.   The image forming apparatus according to claim 10, wherein the charging unit is a charging roller.   The image forming apparatus according to any one of claims 10 to 12, wherein the developing unit cleans the surface of the electrophotographic photosensitive member.   The image forming apparatus according to any one of claims 10 to 13, wherein the charging unit positively charges the surface of the electrophotographic photosensitive member.

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