JP2018189941A - Electrophotographic photoreceptor, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that can reduce an image defect due to an exposure memory, improve repetitive characteristics, and improve ozone resistance.SOLUTION: An electrophotographic photoreceptor 1 comprises a conductive substrate 2 and a single-layer photosensitive layer 3. The photosensitive layer 3 contains a charge generating agent, a hole transport agent, an electron transport agent, a binder resin, and an additive. Light response time is 0.05 milliseconds or more and 0.85 milliseconds or less. A molecular weight of the hole transport agent is 750 or less. A ratio m/mof the mass mof the hole transport agent to the mass mof the electron transport agent is 1.2 or more and 4.0 or less. The additive contains at least one kind of compounds with a specific structure.SELECTED DRAWING: Figure 1

Description

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

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

  In order to prevent discharge products such as ozone from falling and adhering to the surface of the electrophotographic photosensitive member from the vicinity of the charging unit, the image forming apparatus described in Patent Document 1 includes an electrophotographic photosensitive member and a charging unit. Prepare. The charging unit charges the electrophotographic photosensitive member. It has a moving means for moving the charging portion away from the electrophotographic photosensitive member when image formation is stopped.

Japanese Unexamined Patent Publication No. 2017-026682

  However, the image forming apparatus described in Patent Document 1 is insufficient in terms of improving ozone resistance. Further, the inventors have found that the image forming apparatus described in Patent Document 1 is insufficient in terms of suppressing image defects caused by exposure memory and improving repetition characteristics.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an electrophotographic photoreceptor capable of suppressing image defects caused by exposure memory, improving repetition characteristics, and improving ozone resistance. It is to be. Another object of the present invention is to provide an image forming apparatus and a process cartridge that suppress the occurrence of image defects due to exposure memory, deterioration of repetitive characteristics, and influence of ozone.

The electrophotographic photosensitive member of the present invention includes a conductive substrate and a single photosensitive layer. The photosensitive layer contains a charge generating agent, a hole transporting agent, an electron transporting agent, a binder resin, and an additive. The optical response time is not less than 0.05 milliseconds and not more than 0.85 milliseconds. The photoresponse time is the time from when the surface of the photosensitive layer charged with + 800V is irradiated with pulsed light having a wavelength of 780 nm until the surface potential of the photosensitive layer decays from + 800V to + 400V. The intensity of the pulsed light is an intensity at which the surface potential of the photosensitive layer is changed from +800 V to +200 V after 400 milliseconds from the irradiation of the surface of the photosensitive layer charged with +800 V with the pulsed light. The molecular weight of the hole transport agent is 750 or less. A ratio m _HTM / m _ETM of a mass m _HTM of the hole transport agent to a mass m _ETM of the electron transfer agent is 1.2 or more and 4.0 or less. The additive includes at least one of the compounds represented by the general formulas (1) and (2).

In the general formula (1), R ^1A , R ^1B , R ^1C , R ^1D , R ^1E , R ^2A , R ^2B , R ^2C , R ^2D and R ^2E are each independently a hydrogen atom, halogen atom, hydroxyl group Group, cyano group, nitro group, amino group, alkyl group having 1 to 12 carbon atoms which may have a substituent, alkoxy group having 1 to 12 carbon atoms which may have a substituent, substitution An aryl group having 6 to 30 carbon atoms which may have a group, a cycloalkyl group having 3 to 12 carbon atoms which may have a substituent, or a heterocyclic group which may have a substituent Represents. R ³ represents an alkylene group having 1 to 12 carbon atoms which may have a substituent. p represents 0 or 1. In the general formula (2), R ⁴ , R ⁵ and R ⁶ are each independently a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amino group, or a C 1 or more carbon atom which may have a substituent. An alkyl group having 12 or less alkyl, an alkoxy group having 1 to 12 carbon atoms which may have a substituent, an aryl group having 6 to 30 carbon atoms which may have a substituent, or a substituent; And may represent a cycloalkyl group having 3 to 12 carbon atoms. q ₁ and q ₂ each independently represents an integer of 0 or more and 5 or less.

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

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

  According to the electrophotographic photosensitive member of the present invention, it is possible to suppress image defects caused by exposure memory, improve repetitive characteristics, and improve ozone resistance. In addition, the process cartridge and the image forming apparatus of the present invention can suppress image defects caused by exposure memory, deterioration of repetitive characteristics, and influence of ozone.

(A) And (b) is a fragmentary sectional view which respectively shows an example of the electrophotographic photoreceptor which concerns on embodiment of this invention. It is a graph which shows the attenuation curve of the surface potential of a photosensitive layer. 1 is a diagram illustrating an example of an image forming apparatus, and the image forming apparatus includes an electrophotographic photosensitive member according to an embodiment of the present invention. It is a figure which shows the measuring apparatus of optical response time. It is a figure which shows the image for evaluation. It is a figure which shows the image in which the image defect resulting from exposure memory generate | occur | produced.

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

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

  Hereinafter, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 4 carbon atoms, carbon An alkyl group having 1 to 3 atoms, an alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and 1 to 3 carbon atoms Alkoxy groups having 6 to 30 carbon atoms, aryl groups having 6 to 14 carbon atoms, aryl groups having 6 to 10 carbon atoms, aralkyl groups having 7 to 20 carbon atoms, and heterocyclic rings A cycloalkylidene group having 5 to 7 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a carbon atom number of 5 or less A cycloalkane having 7 or less carbon atoms, an alkylene group having 1 to 12 carbon atoms, an alkylene group having 1 to 6 carbon atoms, an alkylene group having 1 to 3 carbon atoms, an acyl group having 2 to 13 carbon atoms, An alkoxycarbonyl group having 2 to 13 carbon atoms has the following meaning unless otherwise specified.

  As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, for example.

  An alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 4 carbon atoms, 1 to 3 carbon atoms The following alkyl groups are each linear or branched and unsubstituted. Examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, A neopentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, and a dodecyl group are mentioned. Examples of the alkyl group having 1 to 6 carbon atoms are groups having 1 to 6 carbon atoms among the groups described as examples of alkyl groups having 1 to 12 carbon atoms. Examples of the alkyl group having 1 to 5 carbon atoms are groups having 1 to 5 carbon atoms among the groups described as examples of alkyl groups having 1 to 12 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms are groups having 1 to 4 carbon atoms among the groups described as examples of alkyl groups having 1 to 12 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms are groups having 1 to 3 carbon atoms among the groups described as examples of alkyl groups having 1 to 12 carbon atoms.

  An alkenyl group having 2 to 4 carbon atoms is linear or branched and unsubstituted. An alkenyl group having 2 to 4 carbon atoms has one or two double bonds. Examples of the alkenyl group having 2 to 4 carbon atoms include an ethenyl group, a propenyl group, a butenyl group, and a butadienyl group.

  The alkoxy group having 1 to 12 carbon atoms, the alkoxy group having 1 to 6 carbon atoms, and the alkoxy group having 1 to 3 carbon atoms are linear or branched and unsubstituted. Examples of the alkoxy group having 1 to 12 carbon atoms include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, pentyloxy, Examples include pentyloxy group, neopentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, nonyloxy group, decyloxy group, undecyloxy group, and dodecyloxy group. Examples of the alkoxy group having 1 to 6 carbon atoms are groups having 1 to 6 carbon atoms among the groups described as examples of alkoxy groups having 1 to 12 carbon atoms. Examples of the alkoxy group having 1 to 3 carbon atoms are groups having 1 to 3 carbon atoms among the groups described as examples of alkoxy groups having 1 to 12 carbon atoms.

  The aryl group having 6 to 30 carbon atoms, the aryl group having 6 to 14 carbon atoms, and the aryl group having 6 to 10 carbon atoms are each unsubstituted. Examples of the aryl group having 6 to 30 carbon atoms include a phenyl group, a naphthyl group, an indacenyl group, a biphenylenyl group, an acenaphthylenyl group, an anthryl group and a phenanthryl group, a tetracenyl group, a tetraphenyl group, a chrysenyl group, a pyrenyl group, and a triphenylenyl group. Group, benzophenanthrenyl group, picenyl group, perylenyl group, pentaphenyl group, tetraphenylenyl group, hexahelicenyl group, hexaphenyl group, hexacenyl group, rubicenyl group, coronenyl group, trinaphthylenyl group, heptaphenyl group and heptacenyl group Is mentioned. Examples of the aryl group having 6 to 14 carbon atoms include a phenyl group, a naphthyl group, an indacenyl group, a biphenylenyl group, an acenaphthylenyl group, an anthryl group, and a phenanthryl group. Examples of the aryl group having 6 to 10 carbon atoms include a phenyl group and a naphthyl group.

  An aralkyl group having 7 to 20 carbon atoms is unsubstituted. The aralkyl group having 7 to 20 carbon atoms is, for example, an alkyl group having 1 to 6 carbon atoms having an aryl group having 6 to 14 carbon atoms.

  Examples of the heterocyclic ring include a heterocyclic group having 5 to 14 members. The 5- to 14-membered heterocyclic group contains at least one heteroatom in addition to the carbon atom and is unsubstituted. The hetero atom is at least one selected from the group consisting of a nitrogen atom, a sulfur atom and an oxygen atom. The 5- to 14-membered heterocyclic group includes, for example, a 5-membered or 6-membered monocyclic heterocyclic group containing 1 to 3 heteroatoms in addition to the carbon atom; A heterocyclic group in which two monocyclic rings are fused; a heterocyclic group in which such a monocyclic heterocyclic ring is fused with a 5- or 6-membered monocyclic hydrocarbon ring; and three such monocyclic heterocyclic rings A fused heterocyclic group; a heterocyclic group fused with two such monocyclic heterocycles and one 5- or 6-membered monocyclic hydrocarbon ring; or such monocyclic heterocycle 1 And a heterocyclic group formed by condensing two and five or six-membered monocyclic hydrocarbon rings. Specific examples of the 5- to 14-membered heterocyclic group include piperidinyl group, piperazinyl group, morpholinyl group, thiophenyl group, furanyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, isothiazolyl group, isoxazolyl group, oxazolyl group, isoxazolyl group Group, thiazolyl group, isothiazolyl group, furazanyl group, pyranyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, indolyl group, 1H-indazolyl group, isoindolyl group, chromenyl group, quinolinyl group, isoquinolinyl group, purinyl group, pteridinyl Group, triazolyl group, tetrazolyl group, 4H-quinolidinyl group, naphthyridinyl group, benzofuranyl group, 1,3-benzodioxolyl group, benzoxazolyl group, benzothiazolyl group, benzimidazolyl group, Rubazoriru group, phenanthridinyl group, acridinyl group, and a phenazinyl group and a phenanthrolinyl group.

  A cycloalkylidene group having 5 to 7 carbon atoms is unsubstituted. Examples of the cycloalkylidene group having 5 to 7 carbon atoms include a cyclopentylidene group, a cyclohexylidene group, and a cycloheptylidene group. A cycloalkylidene group having 5 to 7 carbon atoms is represented by the following general formula. In the general formula, t represents an integer of 1 to 3, and an asterisk represents a bond. It is preferable that t represents 2.

  The cycloalkyl group having 3 to 12 carbon atoms and the cycloalkyl group having 5 to 7 carbon atoms are each unsubstituted. Examples of the cycloalkyl group having 3 to 12 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a cycloundecyl group, and a cyclododecyl group. Groups. Examples of the cycloalkyl group having 5 to 7 carbon atoms are groups having 5 to 7 carbon atoms among the groups described as examples of the cycloalkyl group having 3 to 12 carbon atoms.

  A cycloalkane having 5 to 7 carbon atoms is unsubstituted. Examples of the cycloalkane having 5 to 7 carbon atoms include a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group.

  The alkylene group having 1 to 12 carbon atoms, the alkylene group having 1 to 6 carbon atoms, and the alkylene group having 1 to 3 carbon atoms are each linear or branched and unsubstituted. Examples of the alkylene group having 1 to 12 carbon atoms include methylene group, ethylene group, propylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene group, decylene group, undecylene group and dodecylene group. Is mentioned. Examples of the alkylene group having 1 to 6 carbon atoms are groups having 1 to 6 carbon atoms among the groups described as examples of alkylene groups having 1 to 12 carbon atoms. Examples of the alkylene group having 1 to 3 carbon atoms are groups having 1 to 3 carbon atoms among the groups described as examples of alkylene groups having 1 to 12 carbon atoms.

  Examples of the acyl group having 2 to 13 carbon atoms include a carbonyl group having an alkyl group having 1 to 12 carbon atoms. Examples of the alkoxycarbonyl group having 2 to 13 carbon atoms include a carbonyl group having an alkoxy group having 1 to 12 carbon atoms.

<Electrophotographic photoreceptor>
The present embodiment relates to an electrophotographic photoreceptor (hereinafter sometimes referred to as a photoreceptor). The structure of the photoreceptor 1 will be described with reference to FIG. FIG. 1 is a cross-sectional view illustrating an example of a photoreceptor 1 according to the present embodiment.

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

  As shown in FIG. 1B, the photoreceptor 1 may include 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. As shown in FIG. 1A, the photosensitive layer 3 may be provided directly on the conductive substrate 2. Alternatively, as shown in FIG. 1B, the photosensitive layer 3 may be provided on the conductive substrate 2 via the intermediate layer 4. The intermediate layer 4 may be a single layer or a plurality of layers.

  The photoreceptor 1 may include a conductive substrate 2, a photosensitive layer 3, and a protective layer (not shown). The protective layer is provided on the photosensitive layer 3. The protective layer may be a single layer or a plurality of layers.

  The thickness of the photosensitive layer 3 is not particularly limited. 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. The structure of the photoreceptor 1 has been described above with reference to FIG. Hereinafter, the photoreceptor will be described in more detail.

<Photosensitive layer>
The photosensitive layer contains a charge generating agent, a hole transporting agent, an electron transporting agent, a binder resin, and an additive.

(Light response time)
The photoresponse time of the photoreceptor is from 0.05 milliseconds to 0.85 milliseconds. The photoresponse time is the time from when the surface of the photosensitive layer charged with + 800V is irradiated with pulsed light having a wavelength of 780 nm until the surface potential of the photosensitive layer decays from + 800V to + 400V. The light intensity of the pulsed light is set to an intensity at which the surface potential of the photosensitive layer is changed from +800 V to +200 V after 400 milliseconds from the irradiation of the surface of the photosensitive layer charged with +800 V with the pulsed light having a wavelength of 780 nm.

  The optical response time will be described with reference to FIG. FIG. 2 shows an attenuation curve of the surface potential of the photosensitive layer. The vertical axis represents the surface potential (unit: V) of the photosensitive layer. The horizontal axis indicates time. In the attenuation curve of the surface potential of the photosensitive layer, the time when the surface of the photosensitive layer is irradiated with pulsed light is set to 0.00 milliseconds. As shown by the attenuation curve of the surface potential of the photosensitive layer, the surface potential of the photosensitive layer attenuates from +800 V to +200 V 400 milliseconds after the pulsed light is applied to the surface of the photosensitive layer charged to +800 V. At this time, the time τ from when the surface of the photosensitive layer charged with +800 V is irradiated to the surface potential of the photosensitive layer is attenuated from +800 V to +400 V is defined as the optical response time.

  When the photoresponse time of the photoreceptor is 0.05 milliseconds or more and 0.85 milliseconds or less, it is possible to suppress the occurrence of image defects due to the exposure memory. Here, the exposure memory has a charge potential in the surface area of the photoconductor corresponding to the exposure area of the previous circumference due to the influence of exposure during image formation, and the surface of the photoconductor corresponding to the non-exposure area of the previous circumference. This is a phenomenon that is lower than the above region. When the exposure memory is generated, an image defect occurs in the formed image in which the area corresponding to the exposure area on the periphery of the photoreceptor is darkened. When the photoresponse time of the photoreceptor exceeds 0.85 milliseconds, charges (especially holes) easily remain in the photosensitive layer. Therefore, an image defect caused by the exposure memory occurs. Since a certain amount of time is required for the photoconductor to respond to light, the photoresponse time of the photoconductor can be set to 0.05 milliseconds or more. In addition, when the photoresponse time of the photoconductor is 0.85 milliseconds or less, the repetitive characteristics of the photoconductor described later can be improved.

  In order to suppress the occurrence of image defects due to the exposure memory, the upper limit of the photoresponse time of the photoreceptor is more preferably 0.70 milliseconds, further preferably 0.60 milliseconds, More preferably, it is 0.50 milliseconds. For example, the lower limit of the photoresponse time of the photoconductor may be 0.23 milliseconds.

The photoresponse time of the photoreceptor is measured by the method described in the examples. The photoresponse time of the photoreceptor can be adjusted, for example, by changing the type of the hole transport agent. The photoresponse time of the photoreceptor can also be adjusted by changing the type of electron transport agent, for example. The photoresponse time of the photoreceptor can also be adjusted, for example, by changing the type of additive. The photoresponse time of the photoreceptor can also be adjusted, for example, by changing the content of the hole transport agent with respect to the mass of the photosensitive layer. The photoresponse time of the photoreceptor can also be adjusted, for example, by changing the ratio m _HTM / m _ETM of the mass transfer agent mass m _{HTM to} the electron transfer agent mass m _ETM .

(Additive)
The additive includes at least one of the compounds represented by the general formulas (1) and (2). Hereinafter, the compounds represented by the general formulas (1) and (2) may be referred to as compounds (1) and (2), respectively. When the photosensitive layer contains at least one of the compounds (1) and (2) as additives, the ozone resistance and repeatability of the photoreceptor can be improved. Here, in this specification, the ozone resistance of the photoconductor means that the post-exposure potential in the exposed region of the photoconductor can be lowered to a desired value even when the photoconductor is exposed to ozone. It is a characteristic. When the photosensitive layer contains at least one of the compounds (1) and (2) as an additive, the density of the photosensitive layer is increased and ozone can be prevented from entering the photosensitive layer. As a result, the ozone resistance of the photoreceptor can be improved. In this specification, the repetitive characteristics of a photoconductor means that the surface of the photoconductor can be charged to a desired value even when an image is repeatedly formed on a recording medium using the photoconductor. This is a characteristic capable of maintaining the potential of the non-exposed region of the photoreceptor at a desired value.

In general formula (1), R ^1A , R ^1B , R ^1C , R ^1D , R ^1E , R ^2A , R ^2B , R ^2C , R ^2D and R ^2E are each independently a hydrogen atom, halogen atom, hydroxyl group , A cyano group, a nitro group, an amino group, an alkyl group having 1 to 12 carbon atoms which may have a substituent, an alkoxy group having 1 to 12 carbon atoms which may have a substituent, a substituent An aryl group having 6 to 30 carbon atoms which may have a cycloalkyl group having 3 to 12 carbon atoms which may have a substituent, or a heterocyclic group which may have a substituent. Represent. R ³ represents an alkylene group having 1 to 12 carbon atoms which may have a substituent. p represents 0 or 1.

In the general formula (2), R ⁴ , R ⁵ and R ⁶ are each independently a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amino group, or a C 1 or more carbon atom which may have a substituent. The following alkyl group, an alkoxy group having 1 to 12 carbon atoms which may have a substituent, an aryl group having 6 to 30 carbon atoms which may have a substituent, or a substituent Or a cycloalkyl group having 3 to 12 carbon atoms. q ₁ and q ₂ each independently represents an integer of 0 or more and 5 or less. When q ₁ represents an integer of 2 or more and 5 or less, the plurality of R ⁴ may be the same as or different from each other. When q ₂ represents an integer of 2 or more and 5 or less, the plurality of R ⁵ may be the same as or different from each other.

R ^1A , R ^1B , R ^1C , R ^1D , R ^1E , R ^2A , R ^2B , R ^2C , R ^2D and R ^2E in general formula (1), and R ⁴ , R ^{5 in} general formula (2) And the halogen atom represented by R ⁶ is preferably a chlorine atom or a fluorine atom.

R ^1A , R ^1B , R ^1C , R ^1D , R ^1E , R ^2A , R ^2B , R ^2C , R ^2D and R ^2E in general formula (1), and R ⁴ , R ^{5 in} general formula (2) And the alkyl group having 1 to 12 carbon atoms represented by R ⁶ is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and still more preferably a methyl group. . Such an alkyl group having 1 to 12 carbon atoms may have a substituent. Examples of the substituent of the alkyl group having 1 to 12 carbon atoms include a halogen atom, nitro group, cyano group, amino group, hydroxyl group, carboxyl group, sulfanyl group, carbamoyl group, and 3 to 12 carbon atoms. A cycloalkyl group, an alkoxy group having 1 to 12 carbon atoms, an alkylsulfanyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, and an acyl group having 2 to 13 carbon atoms And an alkoxycarbonyl group having 2 to 13 carbon atoms and an aryl group having 6 to 14 carbon atoms. The number of substituents that the alkyl group having 1 to 12 carbon atoms has is, for example, 1 to 3 inclusive.

R ^1A , R ^1B , R ^1C , R ^1D , R ^1E , R ^2A , R ^2B , R ^2C , R ^2D and R ^2E in general formula (1), and R ⁴ , R ^{5 in} general formula (2) And the alkoxy group having 1 to 12 carbon atoms represented by R ⁶ is preferably an alkoxy group having 1 to 6 carbon atoms. Such an alkoxy group having 1 to 12 carbon atoms may have a substituent. Examples of the substituent of the alkoxy group having 1 to 12 carbon atoms include a halogen atom, nitro group, cyano group, amino group, hydroxyl group, carboxyl group, sulfanyl group, carbamoyl group, and 3 to 12 carbon atoms. A cycloalkyl group, an alkoxy group having 1 to 12 carbon atoms, an alkylsulfanyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, and an acyl group having 2 to 13 carbon atoms And an alkoxycarbonyl group having 2 to 13 carbon atoms and an aryl group having 6 to 14 carbon atoms. The number of substituents that the alkoxy group having 1 to 12 carbon atoms has is, for example, 1 to 3 inclusive.

R ^1A , R ^1B , R ^1C , R ^1D , R ^1E , R ^2A , R ^2B , R ^2C , R ^2D and R ^2E in general formula (1), and R ⁴ , R ^{5 in} general formula (2) And an aryl group having 6 to 30 carbon atoms represented by R ⁶ is preferably an aryl group having 6 to 14 carbon atoms, more preferably an aryl group having 6 to 10 carbon atoms, and still more preferably a phenyl group. . Such an aryl group having 6 to 30 carbon atoms may have a substituent. Examples of the substituent of the aryl group having 6 to 30 carbon atoms include a halogen atom, nitro group, cyano group, amino group, hydroxyl group, carboxyl group, sulfanyl group, carbamoyl group, and 3 to 12 carbon atoms. A cycloalkyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkylsulfanyl group having 1 to 12 carbon atoms, and an alkylsulfonyl group having 1 to 12 carbon atoms And an acyl group having 2 to 13 carbon atoms, an alkoxycarbonyl group having 2 to 13 carbon atoms, and an aryl group having 6 to 14 carbon atoms. The substituent of the aryl group having 6 to 30 carbon atoms is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and 1 to 3 carbon atoms. The following alkyl groups are more preferable, and a methyl group is particularly preferable. The number of substituents of the aryl group having 6 to 30 carbon atoms is, for example, 1 or more and 3 or less. The number of such substituents is preferably 1.

R ^1A , R ^1B , R ^1C , R ^1D , R ^1E , R ^2A , R ^2B , R ^2C , R ^2D and R ^2E in general formula (1), and R ⁴ , R ^{5 in} general formula (2) And the cycloalkyl group having 3 to 12 carbon atoms represented by R ⁶ is preferably a cycloalkyl group having 5 to 7 carbon atoms. Such a cycloalkyl group having 3 to 12 carbon atoms may have a substituent. Examples of the substituent of the cycloalkyl group having 3 to 12 carbon atoms include a halogen atom, nitro group, cyano group, amino group, hydroxyl group, carboxyl group, sulfanyl group, carbamoyl group, 3 to 12 carbon atoms. The following cycloalkyl groups, alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, alkylsulfanyl groups having 1 to 12 carbon atoms, alkylsulfonyl having 1 to 12 carbon atoms Group, an acyl group having 2 to 13 carbon atoms, an alkoxycarbonyl group having 2 to 13 carbon atoms, and an aryl group having 6 to 14 carbon atoms. The number of substituents that the cycloalkyl group having 3 to 12 carbon atoms has is, for example, 1 to 3 inclusive.

The heterocyclic group represented by R ^1A , R ^1B , R ^1C , R ^1D , R ^1E , R ^2A , R ^2B , R ^2C , R ^2D and R ^{2E in the} general formula (1) is 5 to 14 members. The heterocyclic group is preferably. Such a heterocyclic group may have a substituent. Examples of the substituent of the heterocyclic group include a halogen atom, a nitro group, a cyano group, an amino group, a hydroxyl group, a carboxyl group, a sulfanyl group, a carbamoyl group, a cycloalkyl group having 3 to 12 carbon atoms, and a carbon atom. An alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkylsulfanyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, and 2 to 13 carbon atoms. Examples include the following acyl groups, alkoxycarbonyl groups having 2 to 13 carbon atoms, and aryl groups having 6 to 14 carbon atoms. The number of substituents that the heterocyclic group has is, for example, 1 or more and 3 or less.

The alkylene group having 1 to 12 carbon atoms represented by R ³ in the general formula (1) is preferably an alkylene group having 1 to 6 carbon atoms, more preferably an alkylene group having 1 to 3 carbon atoms. More preferred is a methylene group. Such an alkylene group having 1 to 12 carbon atoms may have a substituent. Examples of the substituent of the alkylene group having 1 to 12 carbon atoms include a halogen atom, a nitro group, a cyano group, an amino group, a hydroxyl group, a carboxyl group, a sulfanyl group, a carbamoyl group, and a cyclohexane having 3 to 12 carbon atoms. An alkyl group, an alkoxy group having 1 to 12 carbon atoms, an alkylsulfanyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, an acyl group having 2 to 13 carbon atoms, carbon Examples thereof include an alkoxycarbonyl group having 2 to 13 atoms and an aryl group having 6 to 14 carbon atoms. The number of substituents possessed by an alkylene group having 1 to 12 carbon atoms is, for example, 1 or more and 3 or less.

In general formula (1), R ^1A , R ^1B , R ^1C , R ^1D and R ^1E each preferably represent a hydrogen atom. R ^2A , R ^2B , R ^2C , R ^2D and R ^2E each independently preferably represent a hydrogen atom or an aryl group having 6 to 10 carbon atoms. R ³ preferably represents an alkylene group having 1 to 6 carbon atoms. p preferably represents 0 or 1.

In general formula (2), R ⁴ and R ⁵ preferably each independently represent an alkyl group having 1 to 6 carbon atoms. R ⁶ preferably represents an aryl group having 6 to 10 carbon atoms, which may have an alkyl group having 1 to 6 carbon atoms. q ₁ and q ₂ each independently preferably represents 0 or 1.

  Preferable examples of the compound (1) include compounds represented by the chemical formulas (1-P1), (1-P2), (1-P3) and (1-P4) (hereinafter, the compounds (1-P1 ), (1-P2), (1-P3) and (1-P4)). Preferable examples of compound (2) include compounds represented by chemical formulas (2-P5) and (2-P6) (hereinafter referred to as compounds (2-P5) and (2-P6), respectively). There is). Preferably, at least one of compounds (1) and (2) is preferably compounds (1-P1), (1-P2), (1-P3), (1-P4), (2-P5) and ( 2-P6) at least one of them.

  In order to particularly improve the repetitive characteristics of the photoreceptor, the additive is preferably the compound (1-P1), (1-P2), (2-P5) or (2-P6), and the compound (1-P1) ) Or (1-P2) is more preferable, and the compound (1-P2) is particularly preferable. In order to particularly improve the ozone resistance of the photoreceptor, the additive is preferably the compound (1-P1), (1-P2), (2-P5) or (2-P6), and the compound (1- P2) or (2-P6) is more preferable. In order to shorten the photoresponse time of the photoreceptor, the additive is preferably the compound (1-P1), (1-P2), (2-P5) or (2-P6), and the compound (2-P6) ) Is more preferable.

  In order to improve the ozone resistance and repeatability of the photoreceptor, the content of at least one of the compounds (1) and (2) is 5 parts by mass or more and 30 parts by mass with respect to 100 parts by mass of the binder resin. Or less, more preferably 20 parts by mass or more and 30 parts by mass or less.

  In order to improve the ozone resistance and repeatability of the photoreceptor, the content of at least one of the compounds (1) and (2) with respect to the mass of the photosensitive layer is 1.0% by mass or more and 10.0% by mass or less. It is preferable that it is 2.0 mass% or more and 10.0 mass% or less.

  As an additive, the photosensitive layer may contain only one of the compounds (1) and (2). Further, as the additive, the photosensitive layer may contain two or more of the compounds (1) and (2).

  As the additive, the photosensitive layer may contain only at least one of the compounds (1) and (2). The photosensitive layer may further contain an additive other than the compounds (1) and (2) (hereinafter sometimes referred to as other additives) in addition to the compound (1) or (2). Good. Other additives include, for example, deterioration inhibitors (eg, antioxidants, radical scavengers, singlet quenchers or ultraviolet absorbers), softeners, surface modifiers, extenders, thickeners, dispersions. Stabilizers, waxes, acceptors, donors, surfactants, plasticizers, sensitizers and leveling agents.

(Hole transport agent)
The molecular weight of the hole transport agent is 750 or less. When the molecular weight of the hole transport agent is 750 or less, the density of the photosensitive layer is increased and ozone can be prevented from entering the photosensitive layer. As a result, the ozone resistance of the photoreceptor is improved. Further, when the hole transport agent has a molecular weight of 750 or less, the repetitive characteristics of the photoreceptor are also improved. In order to improve the ozone resistance of the photoreceptor, the molecular weight of the hole transport agent is preferably 675 or less, more preferably 635 or less, further preferably 500 or less, and 480 or less. More preferably it is. In order to improve the repetition characteristics of the photoreceptor, the molecular weight of the hole transport agent is preferably 705 or less, more preferably 635 or less, and even more preferably 610 or less. In addition, the molecular weight of the hole transport agent is preferably 50 or more, and more preferably 450 or more.

  Examples of the hole transport agent include triphenylamine derivatives and diamine derivatives (for example, N, N, N ′, N′-tetraphenylbenzidine derivatives, N, N, N ′, N′-tetraphenylphenylenediamine derivatives, N, N, N ′, N′-tetraphenylnaphthylenediamine derivative, N, N, N ′, N′-tetraphenylphenanthrylenediamine derivative or di (aminophenylethenyl) benzene derivative), oxadiazole series A compound (eg, 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole), a styryl compound (eg, 9- (4-diethylaminostyryl) anthracene), a carbazole compound (eg, , Polyvinylcarbazole), organic polysilane compounds, pyrazoline compounds (for example, 1-phenyl- -(P-dimethylaminophenyl) pyrazoline), hydrazone compound, indole compound, oxazole compound, isoxazole compound, thiazole compound, thiadiazole compound, imidazole compound, pyrazole compound or triazole compound And compounds having a molecular weight of 750 or less. The photosensitive layer may contain only one kind of hole transporting agent, or may contain two or more kinds of hole transporting agents.

  In order to suitably achieve suppression of image defects caused by exposure memory, improvement of repetition characteristics, and improvement of ozone resistance, the hole transport agent is represented by the general formulas (11) to (18) and has a molecular weight. It is preferable that at least 1 sort (s) of the compounds whose is is 750 or less is included. Hereinafter, the compounds represented by the general formulas (11) to (18) and having a molecular weight of 750 or less may be referred to as compounds (11) to (18), respectively. In the present specification, the compound represented by the general formulas (11) to (18) and having a molecular weight of 750 or less has a molecular weight of 750 or less among the compounds represented by the general formulas (11) to (18). Even if it is a compound included by General formula (11)-(18), it does not mean the compound in which molecular weight exceeds 750.

The compound (11) will be described. The compound (11) is a compound having a molecular weight of 750 or less among the compounds represented by the following general formula (11). In general formula (11), Q ¹ , Q ² , Q ³ and Q ⁴ each independently represents an alkyl group having 1 to 6 carbon atoms. b ₁ , b ₂ , b ₃ and b ₄ each independently represent an integer of 0 or more and 5 or less. b ₅ represents 0 or 1.

When b ₁ represents an integer of 2 or more and 5 or less, the plurality of Q ¹ may be the same as or different from each other. When b ₂ represents an integer of 2 or more and 5 or less, the plurality of Q ² may be the same as or different from each other. When b ₃ represents an integer of 2 or more and 5 or less, the plurality of Q ³ may be the same as or different from each other. When b ₄ represents an integer of 2 or more and 5 or less, the plurality of Q ⁴ may be the same as or different from each other.

The alkyl group having 1 to 6 carbon atoms represented by Q ¹ , Q ² , Q ³ and Q ^{4 in the} general formula (11) is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group. preferable.

In general formula (11), Q ¹ , Q ² , Q ³ and Q ⁴ preferably each independently represent an alkyl group having 1 to 3 carbon atoms. It is preferable that b ₁ , b ₂ , b ₃ and b ₄ each independently represent 0 or 1. b ₅ preferably represents 0 or 1.

  The compound (11) is preferably a compound represented by the chemical formulas (11-HT6) and (11-HT7) (hereinafter sometimes referred to as compounds (11-HT6) and (11-HT7), respectively). Can be mentioned.

The compound (12) will be described. The compound (12) is a compound having a molecular weight of 750 or less among the compounds represented by the following general formula (12). In the general formula (12), Q ²¹ and Q ²⁸ are each independently a phenyl group, a hydrogen atom, or an alkyl group having 1 to 6 carbon atoms, which may have an alkyl group having 1 to 6 carbon atoms. Alternatively, it represents an alkoxy group having 1 to 6 carbon atoms. Q ²² and Q ²⁹ each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. Q ²³ , Q ²⁴ , Q ²⁵ , Q ²⁶ and Q ²⁷ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. Two adjacent members of Q ²³ , Q ²⁴ , Q ²⁵ , Q ²⁶ and Q ²⁷ are bonded to each other to form a ring (for example, a cycloalkane having 5 to 7 carbon atoms, specifically, cyclopentane, cyclohexane or Cycloheptane) may be formed. d ₁ and d ₂ each independently represents an integer of 0 or more and 2 or less. d ₃ and d ₄ each independently represents an integer of 0 or more and 5 or less.

When d ₃ represents an integer of 2 or more and 5 or less, the plurality of Q ²² may be the same as or different from each other. When d ₄ represents an integer of 2 or more and 5 or less, the plurality of Q ²⁹ may be the same as or different from each other.

In the general formula (12), Q ²¹ and Q ²⁸ each independently preferably represent a phenyl group which may have an alkyl group having 1 to 6 carbon atoms, or a hydrogen atom. Q ²² and Q ²⁹ each independently preferably represent an alkyl group having 1 to 6 carbon atoms. Q ²³ , Q ²⁴ , Q ²⁵ , Q ²⁶ and Q ²⁷ each independently preferably represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. . Two adjacent ones of Q ²³ , Q ²⁴ , Q ²⁵ , Q ²⁶ and Q ²⁷ may be bonded to each other to form a cycloalkane having 5 to 7 carbon atoms. It is preferable that d ₁ and d ₂ each independently represent an integer of 0 or more and 2 or less. d ₃ and d ₄ are each independently preferably represents 0 or 1.

The phenyl group which may have an alkyl group having 1 to 6 carbon atoms represented by Q ²¹ and Q ²⁸ is preferably a phenyl group which may have an alkyl group having 1 to 3 carbon atoms. A phenyl group which may have a group is more preferable. The alkyl group having 1 to 6 carbon atoms represented by Q ²² and Q ²⁹ is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. The alkyl group having 1 to 6 carbon atoms represented by Q ²³ , Q ²⁴ , Q ²⁵ , Q ²⁶ and Q ²⁷ is preferably an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group or n- A butyl group is more preferable, and a methyl group is still more preferable. The alkoxy group having 1 to 6 carbon atoms represented by Q ²³ , Q ²⁴ , Q ²⁵ , Q ²⁶ and Q ²⁷ is preferably an alkoxy group having 1 to 3 carbon atoms, and more preferably an ethoxy group.

For example, adjacent Q ²³ and Q ^{24 of} Q ²³ , Q ²⁴ , Q ²⁵ , Q ²⁶ and Q ²⁷ may be bonded to each other to form a cycloalkane having 5 to 7 carbon atoms. When two adjacent Q ²³ , Q ²⁴ , Q ²⁵ , Q ²⁶ and Q ²⁷ are bonded to each other to form a cycloalkane having 5 to 7 carbon atoms, the cycloalkane having 5 to 7 carbon atoms The alkane is condensed with a phenyl group to which Q ²³ , Q ²⁴ , Q ²⁵ , Q ²⁶ and Q ²⁷ are bonded to form a bicyclic fused ring group. In this case, the condensation site between the cycloalkane having 5 to 7 carbon atoms and the phenyl group may contain a double bond. Cycloalkane having 5 or more and 7 or less carbon atoms represented by two adjacent Q ²³ , Q ²⁴ , Q ²⁵ , Q ²⁶ and Q ²⁷ bonded to each other is preferable.

In the general formula (12), Q ²¹ and Q ²⁸ are the same, Q ²² and Q ²⁹ are the same, d ₁ and d ₂ are the same integer, and d ₃ and d ₄ are the same integer. Is preferably represented.

  Compound (12) is preferably a compound represented by the chemical formula (12-HT1), (12-HT2), (12-HT3), (12-HT4), (12-HT8) and (12-HT9) ( Hereinafter, the compounds (12-HT1), (12-HT2), (12-HT3), (12-HT4), (12-HT8), and (12-HT9) may be respectively described). .

The compound (13) will be described. The compound (13) is a compound having a molecular weight of 750 or less among the compounds represented by the following general formula (13). In the general formula (13), Q ³¹ , Q ³² , Q ³³ and Q ³⁴ each independently represent an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. e ₁ , e ₂ , e ₃ and e ₄ each independently represents an integer of 0 or more and 5 or less. e ₅ represents 2 or 3.

When e ₁ represents an integer of 2 or more and 5 or less, the plurality of Q ³¹ may be the same as or different from each other. When e ₂ represents an integer of 2 or more and 5 or less, the plurality of Q ³² may be the same as or different from each other. When e ₃ represents an integer of 2 or more and 5 or less, the plurality of Q ³³ may be the same as or different from each other. When e ₄ represents an integer of 2 or more and 5 or less, the plurality of Q ³⁴ may be the same as or different from each other.

In the general formula ^{(13), Q 31, Q} 32, Q 33 and Q ³⁴ are each independently preferably represents a 1 to 6 alkyl group carbon atoms. The alkyl group having 1 to 6 carbon atoms represented by Q ³¹ , Q ³² , Q ³³ and Q ³⁴ is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. It is preferable that e ₁ , e ₂ , e ₃ and e ₄ each independently represent 0 or 1. e ₅ preferably represents 2 or 3.

  Compound (13) is preferably a compound represented by chemical formulas (13-HT10) and (13-HT12) (hereinafter sometimes referred to as compounds (13-HT10) and (13-HT12), respectively). Can be mentioned.

The compound (14) will be described. The compound (14) is a compound having a molecular weight of 750 or less among the compounds represented by the following general formula (14). In the general formula (14), Q ⁴¹ , Q ⁴² and Q ⁴³ each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. f ₁ , f ₂ and f ₃ each independently represents an integer of 0 or more and 5 or less. Q ⁴⁴ , Q ⁴⁵ and Q ⁴⁶ are each independently a phenyl group optionally having an alkyl group having 1 to 6 carbon atoms, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or the number of carbon atoms 1 to 6 alkoxy groups are represented. f ₄ , f ₅ and f ₆ each independently represents 0 or 1;

When f ₁ represents an integer of 2 or more and 5 or less, the plurality of Q ⁴¹ may be the same as or different from each other. When f ₂ represents an integer of 2 or more and 5 or less, the plurality of Q ⁴² may be the same as or different from each other. When f ₃ represents an integer of 2 or more and 4 or less, the plurality of Q ⁴³ may be the same as or different from each other.

In the general formula (14), Q ⁴¹ , Q ⁴² and Q ⁴³ each independently preferably represents an alkyl group having 1 to 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms represented by Q ⁴¹ , Q ⁴² and Q ⁴³ is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. f ₁ , f ₂ and f ₃ each preferably represents 0 or 1. Q ⁴⁴ , Q ⁴⁵ and Q ⁴⁶ each preferably represents a hydrogen atom. f ₄ , f ₅ and f ₆ each preferably represent 0.

  The compound (14) is preferably a compound represented by the chemical formula (14-HT5) (hereinafter sometimes referred to as the compound (14-HT5)).

The compound (15) will be described. The compound (15) is a compound having a molecular weight of 750 or less among the compounds represented by the following general formula (15). In the general formula (15), Q ⁵¹ , Q ⁵² , Q ⁵³ , Q ⁵⁴ , Q ⁵⁵ and Q ⁵⁶ each independently have 2 or more and 4 or less carbon atoms which may have one or more phenyl groups. An alkenyl group, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an alkoxy group having 1 to 6 carbon atoms is represented. h ₃ and h ₆ each independently represents an integer of 0 or more and 4 or less. h ₁ , h ₂ , h ₄ and h ₅ each independently represents an integer of 0 or more and 5 or less.

When h ₃ represents an integer of 2 or more and 4 or less, the plurality of Q ⁵³ may be the same as or different from each other. When h ₆ represents an integer of 2 or more and 4 or less, the plurality of Q ⁵⁶ may be the same as or different from each other. When h ₁ represents an integer of 2 or more and 5 or less, the plurality of Q ⁵¹ may be the same as or different from each other. When h ₂ represents an integer of 2 or more and 5 or less, the plurality of Q ⁵² may be the same as or different from each other. When h ₄ represents an integer of 2 or more and 5 or less, the plurality of Q ⁵⁴ may be the same as or different from each other. When h ₅ represents an integer of 2 or more and 5 or less, the plurality of Q ⁵⁵ may be the same as or different from each other.

In the general formula (15), Q ⁵¹ , Q ⁵² , Q ⁵³ , Q ⁵⁴ , Q ⁵⁵ and Q ⁵⁶ each independently preferably represent an alkyl group having 1 to 6 carbon atoms. h ₃ and h ₆ each preferably represents 0. h ₁ , h ₂ , h ₄ and h ₅ each independently preferably represent an integer of 0 or more and 2 or less. The alkyl group having 1 to 6 carbon atoms represented by Q ⁵¹ , Q ⁵² , Q ⁵³ , Q ⁵⁴ , Q ⁵⁵ and Q ⁵⁶ is preferably an alkyl group having 1 to 3 carbon atoms, a methyl group or an ethyl group Is more preferable.

  The compound (15) is preferably a compound represented by the chemical formula (15-HT13) (hereinafter sometimes referred to as the compound (15-HT13)).

The compound (16) will be described. The compound (16) is a compound having a molecular weight of 750 or less among the compounds represented by the following general formula (16). In the general formula (16), Q ⁶¹ , Q ⁶² , Q ⁶³ and Q ⁶⁴ each independently represents an alkyl group having 1 to 6 carbon atoms. k ₁ , k ₂ , k ₃ and k ₄ each independently represents an integer of 0 or more and 5 or less.

When k ₁ represents an integer of 2 or more and 5 or less, the plurality of Q ⁶¹ may be the same as or different from each other. When k ₂ represents an integer of 2 or more and 5 or less, the plurality of Q ⁶² may be the same as or different from each other. When k ₃ represents an integer of 2 or more and 5 or less, the plurality of Q ⁶³ may be the same as or different from each other. When k ₄ represents an integer of 2 or more and 5 or less, the plurality of Q ⁶⁴ may be the same as or different from each other.

In general formula (16), Q ⁶¹ , Q ⁶² , Q ⁶³ and Q ⁶⁴ each independently preferably represent an alkyl group having 1 to 3 carbon atoms. Preferably, k ₁ , k ₂ , k ₃ and k ₄ each independently represent 0 or 1. The alkyl group having 1 to 3 carbon atoms represented by Q ⁶¹ , Q ⁶² , Q ⁶³ and Q ⁶⁴ is preferably a methyl group.

  As the compound (16), a compound represented by the chemical formula (16-HT11) (hereinafter sometimes referred to as the compound (16-HT11)) is preferable.

The compound (17) will be described. The compound (17) is a compound having a molecular weight of 750 or less among the compounds represented by the following general formula (17). In the general formula (17), Q ⁷¹ , Q ⁷² , Q ⁷³ , Q ⁷⁴ and Q ⁷⁵ are each independently an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, carbon An aryl group having 6 to 14 atoms or an aralkyl group having 7 to 20 carbon atoms is represented. m ₁ represents an integer of 0 or more and 5 or less. n ₁ and n ₂ each independently represents an integer of 0 or more and 2 or less. However, the case where n ₁ represents 1 and n ₂ represents ₁ is excluded.

When m ₁ represents an integer of 2 or more and 5 or less, the plurality of Q ⁷¹ may be the same as or different from each other.

In the general formula (17), Q ⁷¹ , Q ⁷² , Q ⁷³ , Q ⁷⁴ and Q ⁷⁵ each independently preferably represent an alkyl group having 1 to 6 carbon atoms, and 1 to 3 carbon atoms. It is more preferable to represent the alkyl group, and it is more preferable to represent a methyl group or an ethyl group. m ₁ preferably represents 1 or 2, and more preferably represents 2. n ₁ and n ₂ each preferably represent 0.

  The compound (17) is preferably a compound represented by the chemical formula (17-HT16) (hereinafter sometimes referred to as the compound (17-HT16)).

The compound (18) will be described. The compound (18) is a compound having a molecular weight of 750 or less among the compounds represented by the following general formula (18). In the general formula (18), R ⁸¹ and R ⁸² each independently represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 14 carbon atoms, provided that both of R ⁸¹ and R ⁸² Except that represents an aryl group having 6 to 14 carbon atoms. R ⁸³ represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 14 carbon atoms. p ₁ represents an integer of 0 or more and 2 or less. p ₂ represents an integer of 0 to 5.

When p ₂ represents an integer of 2 or more, the plurality of R ⁸³ may be the same as or different from each other.

In the general formula (18), R ⁸¹ and R ⁸² each independently represents an alkyl group having 1 to 3 carbon atoms or a phenyl group, except that both R ⁸¹ and R ⁸² represent a phenyl group. It is preferable. p ₁ preferably represents 1 or 2. p ₂ preferably represents 0.

  The compound (18) is preferably a compound represented by the chemical formula (18-HT17) (hereinafter sometimes referred to as the compound (18-HT17)).

  As the hole transport agent, the photosensitive layer may contain only one of the compounds (11) to (18). In order to particularly suppress image defects caused by the occurrence of exposure memory, it is preferable that the photosensitive layer contains at least two of compounds (11) to (18) as a hole transport agent. It is more preferable that the photosensitive layer contains two types of (A) to (18). Of the compounds (11) to (18), two of the compounds (12), or one of the compounds (12) and one of the compounds (13) are preferable, and the compound (12-HT1 ) And compound (12-HT2); compound (12-HT1) and compound (12-HT8); compound (12-HT1) and compound (12-HT9); or compound (12-HT1) and compound (13-HT12) ) Is more preferable. The photosensitive layer may further contain a hole transport agent other than the compounds (11) to (18) in addition to the compounds (11) to (18).

  In order to particularly suppress image defects caused by exposure memory, the compound (11), (12), (13), (14), (17) or (18) is preferable as the hole transport agent. For the same reason, as the hole transport agent, the compounds (11-HT6), (11-HT7), (12-HT1), (12-HT2), (12-HT3), (12-HT4), (12 -HT8), (12-HT9), (13-HT12), (14-HT5), (17-HT16) or (18-HT17) is preferred.

  In order to particularly improve the repeatability of the photoreceptor, the compound (11), (12), (13), (14), (15), (17) or (18) is preferable as the hole transport agent. Compound (17) or (18) is more preferable. For the same reason, as the hole transport agent, the compounds (11-HT7), (12-HT1), (12-HT2), (12-HT3), (12-HT4), (12-HT8), (12 -HT9), (13-HT12), (14-HT5), (15-HT13), (17-HT16) or (18-HT17) is preferred, and compound (17-HT16) or (18-HT17) is more preferred. preferable.

  In order to particularly improve the ozone resistance of the photoreceptor, the hole transporting agent is preferably the compound (11), (12), (13), (16), (17) or (18). 11), (16), (17), or (18) is more preferable. For the same reason, as the hole transport agent, the compounds (11-HT6), (11-HT7), (12-HT1), (12-HT2), (12-HT3), (12-HT8), (13 -HT10), (16-HT11), (17-HT16) or (18-HT17) is preferred, and the compound (11-HT6), (11-HT7), (16-HT11), (17-HT16) or ( 18-HT17) is more preferred.

  The hole transport agent is preferably at least one of the compounds (11), (13), (16), (17) and (18), and the compounds (11-HT6), (11-HT7), More preferably, it is at least one of (13-HT10), (13-HT12), (14-HT5), (16-HT11), (17-HT16) and (18-HT17).

  In order to suitably achieve suppression of image defects due to exposure memory, improvement of repetitive characteristics, and improvement of ozone resistance, the hole transporting agent is preferably compound (17) or (18). 17-HT16) or (18-HT17) is more preferable.

  The content of the hole transport agent with respect to the mass of the photosensitive layer is preferably 33% by mass to 65% by mass, and more preferably 35% by mass to 60% by mass. When the content ratio of the hole transport agent with respect to the mass of the photosensitive layer is 33% by mass or more, image defects caused by the occurrence of exposure memory can be suitably suppressed. Further, when the content ratio of the hole transport agent with respect to the mass of the photosensitive layer is 33% by mass or more, the repetitive characteristics of the photoreceptor can be suitably improved. On the other hand, when the content of the hole transport agent with respect to the mass of the photosensitive layer is 65% by mass or less, the ozone resistance of the photoreceptor and the repetitive characteristics of the photoreceptor can be further improved. Further, when the content of the hole transport agent with respect to the mass of the photosensitive layer is 65% by mass or less, it is possible to further suppress image defects due to the occurrence of exposure memory. Further, when the content of the hole transport agent with respect to the mass of the photosensitive layer is 65% by mass or less, crystallization of the photosensitive layer is difficult to occur.

The ratio m _HTM / m _ETM mass m _HTM of the hole transport agent to the mass m _ETM of the electron transport agent is 1.2 to 4.0. When the ratio m _HTM / m _ETM is 1.2 or more, image defects caused by the occurrence of exposure memory can be suitably suppressed. Further, when the ratio m _HTM / m _ETM is 1.2 or more, the repetitive characteristics of the photoreceptor can be preferably improved. On the other hand, when the ratio m _HTM / m _ETM is 4.0 or less, the ozone resistance of the photoconductor and the repetitive characteristics of the photoconductor can be further improved. The ratio m _HTM / m _ETM of the mass m _HTM of the hole transport agent to the mass m _ETM of the electron transfer agent is preferably 1.5 or more and 3.5 or less. When two or more kinds of electron transport agents are contained in the photosensitive layer, the mass m _ETM of the electron transport agent is the total mass of the two or more kinds of electron transport agents. Further, when two or more hole transport agents are contained in the photosensitive layer, the mass m _HTM of the hole transport agent is the total mass of the two or more hole transport agents.

  The content of the hole transport agent contained in the photosensitive layer is preferably 10 parts by mass or more and 300 parts by mass or less, and preferably 60 parts by mass or more and 250 parts by mass or less with respect to 100 parts by mass of the binder resin. More preferred.

(Electron transfer agent)
Examples of the electron transfer agent include quinone compounds, diimide compounds, hydrazone compounds, malononitrile compounds, thiopyran compounds, trinitrothioxanthone compounds, 3,4,5,7-tetranitro-9-fluorenone compounds, Examples include dinitroanthracene compounds, dinitroacridine compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroacridine, succinic anhydride, maleic anhydride and dibromomaleic anhydride. Examples of quinone compounds include diphenoquinone compounds, azoquinone compounds, anthraquinone compounds, naphthoquinone compounds, nitroanthraquinone compounds, and dinitroanthraquinone compounds. These electron transfer agents may be used alone or in combination of two or more.

  Among these electron transfer agents, suitable examples of the electron transfer agent include compounds represented by the general formulas (21), (22) and (23) (hereinafter referred to as compounds (21) to (23), respectively). May be described).

In general formula (21), R ¹¹ and R ¹² are each independently 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. Alternatively, it represents an aralkyl group having 7 to 20 carbon atoms.

In general formula (21), R ¹¹ and R ¹² preferably each independently represent an alkyl group having 1 to 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms represented by R ¹¹ and R ¹² in the general formula (21) is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a 1,1-dimethylpropyl group. .

  As the compound (21), a compound represented by the chemical formula (ET1) (hereinafter sometimes referred to as the compound (ET1)) is preferable.

In the general formula (22), R ²¹ , R ²² and R ²³ each independently have a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom. And an aryl group having 6 to 14 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or a heterocyclic group having 5 to 14 members.

In the general formula (22), R ²¹ and R ²² each independently represents an alkyl group having 1 to 6 carbon atoms, and R ²³ has 6 to 14 carbon atoms which may have a halogen atom. It is preferable to represent the aryl group. The alkyl group having 1 to 6 carbon atoms represented by R ²¹ and R ²² is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a tert-butyl group. The aryl group having 6 to 14 carbon atoms represented by R ²³ is preferably an aryl group having 6 to 10 carbon atoms, and more preferably a phenyl group. The aryl group having 6 to 14 carbon atoms represented by R ²³ may have a halogen atom. As such a halogen atom, a fluorine atom or a chlorine atom is preferable, and a chlorine atom is more preferable. The number of halogen atoms contained in the aryl group having 6 to 14 carbon atoms represented by R ²³ is preferably 1 or more and 3 or less, and more preferably 1.

  As the compound (22), a compound represented by the chemical formula (ET2) (hereinafter sometimes referred to as the compound (ET2)) is preferable.

In general formula (23), R ³¹ and R ³² each independently represent a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an amino group, or a substituent. An aryl group having 6 to 14 carbon atoms which may be present.

In the general formula (23), R ³¹ and R ³² each independently preferably represents an aryl group having up to 14 which may having 6 or more carbon atoms have a substituent. The aryl group having 6 to 14 carbon atoms represented by R ³¹ and R ³² is preferably an aryl group having 6 to 10 carbon atoms, and more preferably a phenyl group. The aryl group having 6 to 14 carbon atoms represented by R ³¹ and R ³² may have a substituent. Examples of such a substituent include a halogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and 6 to 14 carbon atoms. The following aryl groups are mentioned. As the substituent of the aryl group having 6 to 14 carbon atoms represented by R ³¹ and R ³² , an alkyl group having 1 to 6 carbon atoms is preferable, and an alkyl group having 1 to 3 carbon atoms is more preferable. Further, a methyl group or an ethyl group is more preferable. The number of substituents of the aryl group having 6 to 14 carbon atoms represented by R ³¹ and R ³² is preferably 1 or more, 3 or less, more preferably 1 or more and 2 or less, and 2 Is more preferable.

  As the compound (23), a compound represented by the chemical formula (ET3) (hereinafter sometimes referred to as the compound (ET3)) is preferable.

  In order to improve the repetitive characteristics of the photoreceptor, the electron transporting agent is preferably the compound (21), more preferably the compound (ET1).

  The photosensitive layer may contain only one of the compounds (21), (22) and (23) as an electron transport agent. Further, the photosensitive layer may contain two or more compounds (21), (22) and (23) as an electron transport agent. In addition to the compound (21), (22) or (23), the photosensitive layer may further contain an electron transport agent other than the compounds (21), (22) and (23) as an electron transport agent. Good.

  The content of the electron transport agent is preferably 20 parts by mass or more and 100 parts by mass or less, and more preferably 40 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the binder resin.

(Binder resin)
Examples of the binder resin include a thermoplastic resin, a thermosetting resin, and a photocurable resin. Examples of the thermoplastic resin include polycarbonate resin, polyarylate resin, styrene-butadiene 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 Examples include resins, ketone resins, polyvinyl butyral resins, polyester resins, and polyether resins. As a thermosetting resin, a silicone resin, an epoxy resin, a phenol resin, a urea resin, and a melamine resin are mentioned, for example. As photocurable resin, the acrylic acid adduct of an epoxy compound and the acrylic acid adduct of a urethane compound are mentioned, for example. Binder resin may be used individually by 1 type, and may be used in combination of 2 or more type.

  As the binder resin, a polycarbonate resin having a repeating unit represented by the general formula (31) (hereinafter sometimes referred to as a polycarbonate resin (31)) is preferable.

In the general formula (31), R ⁴¹ , R ⁴² , R ⁴³ and R ⁴⁴ are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms which may have a halogen atom, or the number of carbon atoms Represents 6 or more and 14 or less aryl group. R ⁴³ and R ⁴⁴ may be bonded to each other to represent a cycloalkylidene group having 5 to 7 carbon atoms.

As the alkyl group having 1 to 3 carbon atoms represented by R ⁴¹ , R ⁴² , R ⁴³ and R ^{44 in the} general formula (31), a methyl group or an ethyl group is preferable. The alkyl group having 1 to 3 carbon atoms represented by R ⁴¹ , R ⁴² , R ⁴³ and R ⁴⁴ may have a halogen atom. The halogen atom contained in the alkyl group having 1 to 3 carbon atoms is preferably a fluorine atom or a chlorine atom, and more preferably a fluorine atom. The number of halogen atoms contained in the alkyl group having 1 to 3 carbon atoms is preferably 1 or more, 7 or less, more preferably 1 or more and 5 or less, and still more preferably 1 or more and 3 or less.

The aryl group having 6 to 14 carbon atoms represented by R ⁴¹ , R ⁴² , R ⁴³ and R ^{44 in the} general formula (31) is preferably an aryl group having 6 to 10 carbon atoms, more preferably a phenyl group. preferable.

As the cycloalkylidene group having 5 to 7 carbon atoms represented by R ⁴³ and R ⁴⁴ in the general formula (31) bonded to each other, a cyclohexylidene group is preferable.

In the general formula (31), R ⁴¹ and R ⁴² each independently preferably represents a hydrogen atom or a halogen atom 3 an alkyl group having 1 or more which may carbon atoms have. R ⁴³ and R ⁴⁴ each independently represent an alkyl group having 1 to 3 carbon atoms, or R ⁴³ and R ⁴⁴ may be bonded to each other to represent a cycloalkylidene group having 5 to 7 carbon atoms. preferable.

  Preferable examples of the polycarbonate resin (31) include a polycarbonate resin having a repeating unit represented by the chemical formula (R1) and a polycarbonate resin having a repeating unit represented by the chemical formula (R2) (hereinafter, the polycarbonate resin ( R1) and (R2)).

  The viscosity average molecular weight of the polycarbonate resin (31) is preferably 25,000 or more and 60,000 or less, and more preferably 35,000 or more and 53,000 or less. When the viscosity average molecular weight of the polycarbonate resin (31) is 25,000 or more, the hardness of the photosensitive layer can be suitably improved. When the viscosity average molecular weight of the polycarbonate resin (31) is 60,000 or less, the polycarbonate resin (31) is easily dissolved in the solvent for forming the photosensitive layer, and the photosensitive layer can be suitably formed.

  The polycarbonate resin (31) may have only the repeating unit represented by the general formula (31) as the repeating unit. Further, the polycarbonate resin (31) may further have a repeating unit other than the repeating unit represented by the general formula (31) in addition to the repeating unit represented by the general formula (31) as the repeating unit. Good. The ratio of the number of repeating units represented by the general formula (31) to the total number of repeating units of the polycarbonate resin (31) is preferably 0.80 or more, and more preferably 0.90 or more. 1.00 is particularly preferable.

  The photosensitive layer may contain only one kind of polycarbonate resin (31) as a binder resin. Further, the photosensitive layer may contain two or more kinds of polycarbonate resin (31) as a binder resin. In addition to the polycarbonate resin (31), the photosensitive layer may further contain a binder resin other than the polycarbonate resin (31) as a binder resin.

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

  Examples of the phthalocyanine pigment include metal-free phthalocyanine and metal phthalocyanine. Examples of the metal phthalocyanine include titanyl phthalocyanine, hydroxygallium phthalocyanine, and chlorogallium phthalocyanine. Titanyl phthalocyanine is represented, for example, by the chemical formula (CG1). Metal-free phthalocyanine is represented, for example, by the chemical formula (CG2).

  The phthalocyanine pigment may be crystalline or non-crystalline. The crystal shape of the phthalocyanine pigment (for example, α type, β type, Y type, V type or II type) is not particularly limited, and phthalocyanine pigments having various crystal shapes are used. Examples of the crystal of metal-free phthalocyanine include an X-type crystal of metal-free phthalocyanine (hereinafter sometimes referred to as X-type metal-free phthalocyanine). Examples of the titanyl phthalocyanine crystal include α-type, β-type, and Y-type crystals of titanyl phthalocyanine (hereinafter sometimes referred to as α-type, β-type, and Y-type titanyl phthalocyanine), respectively.

  For example, in a digital optical image forming apparatus (for example, a laser beam printer or a facsimile using a light source such as a semiconductor laser), it is preferable to use a photoreceptor having sensitivity in a wavelength region of 700 nm or more. Since it has a high quantum yield in a wavelength region of 700 nm or more, the charge generator is preferably a phthalocyanine pigment, more preferably a metal-free phthalocyanine or titanyl phthalocyanine, and even more preferably an X-type metal-free phthalocyanine or a Y-type titanyl phthalocyanine. . In particular, Y-type titanyl phthalocyanine is particularly preferable as the charge generating agent in order to suppress image defects caused by the transfer memory.

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

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

  In a photoreceptor 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 or more and 550 nm or less), an sanslon pigment is preferably used as a charge generating agent.

  The content of the charge generating agent is preferably 0.1 parts by weight or more and 50 parts by weight or less, and 0.5 parts by weight or more and 30 parts by weight or less with respect to 100 parts by weight of the binder resin contained in the photosensitive layer. More preferably, it is 0.5 parts by mass or more and 5 parts by mass or less.

(Combination of materials)
In order to suitably suppress image defects caused by exposure memory, improve the repetitive characteristics of the photoconductor, and improve the ozone resistance of the photoconductor, the additive and the hole transporting agent have the following combinations. Either is preferable.
Whether the additive comprises compound (1) and the hole transporting agent comprises compound (12);
Whether the additive comprises compound (2) and the hole transporting agent comprises compound (12);
Whether the additive comprises compound (1) and the two hole transporting agents comprise compound (12);
Whether the additive comprises compound (1) and the hole transporting agent comprises compound (14);
Whether the additive comprises compound (1) and the hole transporting agent comprises compound (11);
Whether the additive comprises compound (1) and the hole transporting agent comprises compound (13);
Whether the additive comprises compound (1) and the hole transporting agent comprises compound (16);
Whether the additive comprises compound (1) and the hole transporting agent comprises compound (12) and compound (13);
Whether the additive comprises compound (1) and the hole transporting agent comprises compound (15);
The additive comprises compound (1) and the hole transport agent comprises compound (17); or the additive comprises compound (1) and the hole transport agent comprises compound (18).

In order to suitably suppress image defects caused by exposure memory, improve the repetitive characteristics of the photoconductor, and improve the ozone resistance of the photoconductor, the additive and the hole transporting agent have the following combinations. More preferably, it is either.
Whether the additive comprises compound (1-P2) and the hole transporting agent comprises compound (12-HT1);
Whether the additive comprises compound (1-P1) and the hole transporting agent comprises compound (12-HT1);
Whether the additive comprises compound (1-P3) and the hole transporting agent comprises compound (12-HT1);
Whether the additive comprises compound (1-P4) and the hole transporting agent comprises compound (12-HT1);
Whether the additive comprises compound (2-P5) and the hole transporting agent comprises compound (12-HT1);
Whether the additive comprises compound (2-P6) and the hole transporting agent comprises compound (12-HT1);
Whether the additive comprises compound (1-P2) and the hole transporting agent comprises compound (12-HT1) and compound (12-HT2);
Whether the additive comprises compound (1-P2) and the hole transporting agent comprises compound (12-HT3);
Whether the additive comprises compound (1-P2) and the hole transporting agent comprises compound (12-HT4);
Whether the additive comprises compound (1-P2) and the hole transporting agent comprises compound (14-HT5);
Whether the additive comprises compound (1-P2) and the hole transporting agent comprises compound (11-HT6);
Whether the additive comprises compound (1-P2) and the hole transporting agent comprises compound (11-HT7);
Whether the additive comprises compound (1-P2) and the hole transporting agent comprises compound (12-HT1) and compound (12-H8);
Whether the additive comprises compound (1-P2) and the hole transporting agent comprises compound (12-HT1) and compound (12-HT9);
Whether the additive comprises compound (1-P2) and the hole transporting agent comprises compound (13-HT10);
Whether the additive comprises compound (1-P2) and the hole transporting agent comprises compound (16-HT11);
Whether the additive comprises compound (1-P2) and the hole transport agent comprises compound (12-HT1) and compound (13-HT12);
Whether the additive comprises compound (1-P2) and the hole transporting agent comprises compound (15-HT13);
The additive comprises compound (1-P2) and the hole transport agent comprises compound (17-HT16); or the additive comprises compound (1-P2) and the hole transport agent comprises compound (18-HT17). )including.

In order to suitably suppress image defects caused by exposure memory, improve the repetitive characteristics of the photoconductor, and improve the ozone resistance of the photoconductor, additives, hole transport agents and electron transport agents include the following: It is preferable that any one of the combinations shown in FIG.
Whether the additive comprises compound (1), the hole transport agent comprises compound (12), and the electron transport agent comprises compound (21);
Whether the additive comprises compound (2), the hole transport agent comprises compound (12), and the electron transport agent comprises compound (21);
Whether the additive comprises compound (1), the two hole transporting agents comprise compound (12), and the electron transporting agent comprises compound (21);
Whether the additive comprises compound (1), the hole transport agent comprises compound (14), and the electron transport agent comprises compound (21);
Whether the additive comprises compound (1), the hole transport agent comprises compound (11), and the electron transport agent comprises compound (21);
Whether the additive comprises compound (1), the hole transport agent comprises compound (13), and the electron transport agent comprises compound (21);
Whether the additive comprises compound (1), the hole transport agent comprises compound (16), and the electron transport agent comprises compound (21);
Whether the additive comprises compound (1), the hole transporting agent comprises compound (12) and compound (13), and the electron transporting agent comprises compound (21);
Whether the additive comprises compound (1), the hole transport agent comprises compound (15), and the electron transport agent comprises compound (21);
Whether the additive comprises compound (1), the hole transport agent comprises compound (12), and the electron transport agent comprises compound (22);
Whether the additive comprises compound (1), the hole transport agent comprises compound (12), and the electron transport agent comprises compound (23);
The additive comprises compound (1) and the hole transport agent comprises compound (17) and the electron transport agent comprises compound (21); or the additive comprises compound (1) and the hole transport agent comprises Compound (18) is included, and the electron transport agent includes compound (21).

In order to suitably suppress image defects caused by exposure memory, improve the repetitive characteristics of the photoconductor, and improve the ozone resistance of the photoconductor, additives, hole transport agents and electron transport agents include the following: It is more preferable that any one of the combinations shown in FIG.
Whether the additive comprises compound (1-P2), the hole transport agent comprises compound (12-HT1), and the electron transport agent comprises compound (ET1);
Whether the additive comprises compound (1-P1), the hole transport agent comprises compound (12-HT1), and the electron transport agent comprises compound (ET1);
Whether the additive comprises compound (1-P3), the hole transport agent comprises compound (12-HT1), and the electron transport agent comprises compound (ET1);
Whether the additive comprises compound (1-P4), the hole transport agent comprises compound (12-HT1), and the electron transport agent comprises compound (ET1);
Whether the additive comprises compound (2-P5), the hole transport agent comprises compound (12-HT1), and the electron transport agent comprises compound (ET1);
Whether the additive comprises compound (2-P6), the hole transport agent comprises compound (12-HT1), and the electron transport agent comprises compound (ET1);
Whether the additive comprises compound (1-P2), the hole transport agent comprises compound (12-HT1), and the electron transport agent comprises compound (ET1);
Whether the additive includes the compound (1-P2), the hole transport agent includes the compound (12-HT1) and the compound (12-HT2), and the electron transport agent includes the compound (ET1);
Whether the additive comprises compound (1-P2), the hole transport agent comprises compound (12-HT3), and the electron transport agent comprises compound (ET1);
Whether the additive includes the compound (1-P2), the hole transport agent includes the compound (12-HT4), and the electron transport agent includes the compound (ET1);
Whether the additive comprises compound (1-P2), the hole transport agent comprises compound (14-HT5), and the electron transport agent comprises compound (ET1);
Whether the additive comprises compound (1-P2), the hole transport agent comprises compound (11-HT6), and the electron transport agent comprises compound (ET1);
Whether the additive includes the compound (1-P2), the hole transport agent includes the compound (11-HT7), and the electron transport agent includes the compound (ET1);
Whether the additive includes the compound (1-P2), the hole transport agent includes the compound (12-HT1) and the compound (12-H8), and the electron transport agent includes the compound (ET1);
Whether the additive includes the compound (1-P2), the hole transport agent includes the compound (12-HT1) and the compound (12-HT9), and the electron transport agent includes the compound (ET1);
Whether the additive comprises compound (1-P2), the hole transport agent comprises compound (13-HT10), and the electron transport agent comprises compound (ET1);
Whether the additive comprises compound (1-P2), the hole transporting agent comprises compound (16-HT11), and the electron transporting agent comprises compound (ET1);
Whether the additive includes the compound (1-P2), the hole transport agent includes the compound (12-HT1) and the compound (13-HT12), and the electron transport agent includes the compound (ET1);
Whether the additive comprises compound (1-P2), the hole transport agent comprises compound (15-HT13), and the electron transport agent comprises compound (ET1);
Whether the additive comprises compound (1-P2), the hole transport agent comprises compound (12-HT1), and the electron transport agent comprises compound (ET2);
Whether the additive comprises compound (1-P2), the hole transport agent comprises compound (12-HT1), and the electron transport agent comprises compound (ET3);
The additive comprises compound (1-P2), the hole transport agent comprises compound (17-HT16), and the electron transport agent comprises compound (ET1); or the additive comprises compound (1-P2) The hole transporting agent includes the compound (18-HT17), and the electron transporting agent includes the compound (ET1).

  In order to suitably achieve suppression of image defects caused by exposure memory, improvement of repetitive characteristics of the photoconductor, and improvement of ozone resistance of the photoconductor, additives, hole transport agents and electron transport agents are used as described above. Any of the combinations is preferable, and the binder resin is preferably a polycarbonate resin (R1). For the same reason, it is preferable that the additive, the hole transport agent and the electron transport agent are any of the above-mentioned combinations, and the charge generating agent is Y-type titanyl phthalocyanine. For the same reason, it is preferable that the additive, the hole transport agent, and the electron transport agent are any of the above combinations, the binder resin is a polycarbonate resin (R1), and the charge generating agent is Y-type titanyl phthalocyanine.

<Conductive substrate>
The conductive substrate is not particularly limited as long as it can be used as the conductive substrate of the photoreceptor. The conductive substrate may be formed of a material having at least a surface portion having conductivity. An example of the conductive substrate is a conductive substrate formed of a conductive material. Another example of the conductive substrate is a conductive substrate coated with a conductive material. Examples of the conductive material include aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, and brass. These conductive materials may be used alone or in combination of two or more (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 according to the structure of the image forming apparatus. Examples of the shape of the conductive substrate include a sheet shape and a drum shape. The thickness of the conductive substrate is appropriately selected according to the shape of the conductive substrate.

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

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

  The resin for the intermediate layer is not particularly limited as long as it can be used as a resin for forming the intermediate layer. The intermediate layer may contain an additive. Examples of the additive contained in the intermediate layer are the same as those of the additive contained in the photosensitive layer.

<Method for producing photoconductor>
The photoreceptor is manufactured, for example, as follows. The photoreceptor is manufactured by applying a coating solution for the photosensitive layer onto a conductive substrate and drying. The coating solution for the photosensitive layer is a charge generator, an electron transport agent, a binder resin, a hole transport agent, at least one of the compounds (1) and (2) as additives, and a component added as necessary ( For example, it is produced by dissolving or dispersing other additives) in a solvent.

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

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

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

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

  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) is mentioned using a high-temperature dryer or a vacuum dryer. The heat treatment temperature is, for example, 40 ° C. or higher and 150 ° C. or lower. The heat treatment time is, for example, not less than 3 minutes and not more than 120 minutes.

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

<Image forming apparatus>
Hereinafter, an image forming apparatus including the photoconductor of the present embodiment will be described. Hereinafter, a color image forming apparatus employing a direct transfer system and a tandem system will be described as an example of an image forming apparatus including the photosensitive member of the present embodiment, with reference to FIG.

  An image forming apparatus 90 shown in FIG. 3 includes image forming units 40 a, 40 b, 40 c and 40 d, a transfer belt 38, and a fixing unit 36. Hereinafter, when it is not necessary to distinguish, each of the image forming units 40a, 40b, 40c, and 40d is referred to as an image forming unit 40.

  The image forming unit 40 includes an image carrier 30, a charging unit 42, an exposure unit 44, a developing unit 46, and a transfer unit 48. The image carrier 30 is the photoreceptor 1 of the present embodiment. An image carrier 30 is provided at the center position of the image forming unit 40. The image carrier 30 is provided to be rotatable in the arrow direction (counterclockwise). Around the image carrier 30, a charging unit 42, an exposure unit 44, a developing unit 46, and a transfer unit 48 are provided in order from the upstream side in the rotation direction of the image carrier 30 with respect to the charging unit 42. . The image forming unit 40 may further include one or both of a cleaning unit (not shown, specifically a blade cleaning unit) and a charge eliminating unit (not shown). Note that the image forming unit 40 may not include a cleaning blade. That is, the image forming apparatus 90 can employ a blade cleaningless system.

  By each of the image forming units 40a to 40d, toner images of a plurality of colors (for example, four colors of black, cyan, magenta, and yellow) are sequentially superimposed on the recording medium M on the transfer belt 38.

  The charging unit 42 charges the surface (specifically, the peripheral surface) of the image carrier 30. The charging polarity of the charging unit 42 is positive. That is, the charging unit 42 charges the surface of the image carrier 30 to a positive polarity.

  The charging unit 42 is a charging roller. The charging roller charges the surface of the image carrier 30 while being in contact with the surface of the image carrier 30. The image forming apparatus 90 employs a contact charging method. Examples of the contact charging type charging unit other than the charging roller include a charging brush. The charging unit may be a non-contact type. Examples of the non-contact type charging unit include a corotron charger and a scorotron charger.

  The exposure unit 44 exposes the surface of the charged image carrier 30. As a result, an electrostatic latent image is formed on the surface of the image carrier 30. The electrostatic latent image is formed based on image data input to the image forming apparatus 90.

  The developing unit 46 supplies toner to the surface of the image carrier 30. Thereby, the developing unit 46 develops the electrostatic latent image as a toner image. As a result, the image carrier 30 carries the toner image. The developer may be a one-component developer or a two-component developer. When the developer is a one-component developer, the developing unit 46 supplies toner that is a one-component developer to the electrostatic latent image formed on the surface of the image carrier 30. When the developer is a two-component developer, the developing unit 46 supplies toner from the toner and carrier contained in the two-component developer to the electrostatic latent image formed on the surface of the image carrier 30.

  The time from when a predetermined portion on the surface of the image carrier 30 is exposed by the exposure unit 44 to development by the developing unit 46 (hereinafter, may be referred to as a process time between exposure and development) is: 100 milliseconds or less. More specifically, the process time between exposure and development is more specifically determined by the developing unit 46 after the exposure light irradiated by the exposure unit 44 starts irradiating a predetermined site on the surface of the image carrier 30. This is the time until the toner starts to be supplied. The predetermined location on the surface of the image carrier 30 is, for example, one point in the exposed region of the peripheral surface of the image carrier 30. The process time between exposure and development corresponds to the peripheral speed of the image carrier 30.

  Usually, when the process time between exposure and development is 100 milliseconds or less, the peripheral speed of the image carrier is high, and charges are likely to remain in the photosensitive layer of the image carrier. Therefore, image defects due to the exposure memory are likely to occur. However, the image forming apparatus 90 includes the photoreceptor 1 according to the present embodiment as the image carrier 30. The photoreceptor 1 can suppress image defects caused by the exposure memory. For this reason, the image forming apparatus 90 including the photoreceptor 1 as the image carrier 30 can suppress image defects caused by the exposure memory even if the process time between exposure and development is 100 milliseconds or less. it can.

  The process time between exposure and development is preferably greater than 0 milliseconds and 100 milliseconds or less, more preferably 50 milliseconds or more and 90 milliseconds or less, and 65 milliseconds or more and 70 milliseconds or less. More preferably it is.

  The transfer belt 38 conveys the recording medium M between the image carrier 30 and the transfer unit 48. The transfer belt 38 is an endless belt. The transfer belt 38 is provided to be rotatable in the arrow direction (clockwise).

  The transfer unit 48 transfers the toner image developed by the developing unit 46 from the surface of the image carrier 30 to the transfer target. The transfer target is the recording medium M. An example of the transfer unit 48 is a transfer roller.

  The area on the surface of the image carrier 30 where the transfer unit 48 has finished transferring the toner image from the surface of the image carrier 30 to the recording medium M, which is a transfer target, is charged again by the charging unit 42 without being neutralized. The That is, the image forming apparatus 90 can employ a so-called static elimination-less method. Usually, in an image forming apparatus that employs a static elimination-less method, electric charges are likely to remain in the photosensitive layer of the image carrier. Therefore, image defects due to the exposure memory are likely to occur. However, the image forming apparatus 90 includes the photoreceptor 1 according to the present embodiment as the image carrier 30. The photoreceptor 1 can suppress the occurrence of image defects caused by the exposure memory. For this reason, the image forming apparatus 90 including the photoreceptor 1 as the image carrier 30 can suppress the occurrence of image defects due to the exposure memory even when the static elimination-less method is employed.

  The fixing unit 36 heats and / or pressurizes the unfixed toner image transferred to the recording medium M by the transfer unit 48. The fixing unit 36 is, for example, a heating roller and / or a pressure roller. The toner image is fixed on the recording medium M by heating and / or pressurizing the toner image. As a result, an image is formed on the recording medium M.

  Although an example of the image forming apparatus has been described above, the image forming apparatus is not limited to the image forming apparatus 90 described above. Although the image forming apparatus 90 described above is a color image forming apparatus, the image forming apparatus may be a monochrome image forming apparatus. In this case, the image forming apparatus may include only one image forming unit, for example. Further, although the image forming apparatus 90 described above employs a tandem system, the image forming apparatus may employ, for example, a rotary system. Further, although the image forming apparatus 90 described above employs the direct transfer method, the image forming apparatus may employ an intermediate transfer method, for example. In this case, the transfer portion corresponds to a primary transfer portion and a secondary transfer portion, and the transfer target corresponds to a recording medium and a transfer belt.

<Process cartridge>
With continuing reference to FIG. 3, an example of a process cartridge including the photoreceptor 1 of the present embodiment will be described. The process cartridge is an image forming cartridge. The process cartridge corresponds to each of the image forming units 40a to 40d. The process cartridge includes an image carrier 30. The image carrier 30 is the photoreceptor 1 according to the present embodiment. In addition to the photoreceptor 1, the process cartridge may further include 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. The process cartridge may further include one or both of a cleaning unit (not shown) and a charge removal unit (not shown). The process cartridge is designed to be detachable from the image forming apparatus 90. Therefore, the process cartridge is easy to handle, and when the sensitivity characteristics of the photoconductor 1 deteriorate, the process cartridge including the photoconductor 1 can be replaced easily and quickly. The process cartridge provided with the photoreceptor 1 of the present embodiment has been described above with reference to FIG.

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

<Material for forming photosensitive layer>
The following electron transport agent, hole transport agent, charge generator, binder resin and additive were prepared as materials for forming the photosensitive layer of the photoreceptor.

(Electron transfer agent)
As the electron transport agent, the compounds (ET1) to (ET3) described in the embodiment were prepared.

(Hole transport agent)
As the hole transport agent, the compounds (11-HT6), (11-HT7), (12-HT1), (12-HT2), (12-HT3), (12-HT4), (12) described in the embodiment are used. -HT8), (12-HT9), (13-HT10), (13-HT12), (14-HT5), (15-HT13), (16-HT11) and (17-HT16) were prepared. Further, as hole transporting agents, compounds represented by the following chemical formulas (HT14) and (HT15) (hereinafter, sometimes referred to as compounds (HT14) and (HT15), respectively) were also prepared. Tables 1 to 3 show the molecular weights of these compounds prepared as hole transport agents.

(Charge generator)
Y-type titanyl phthalocyanine and X-type metal-free phthalocyanine were prepared as charge generating agents. The Y-type titanyl phthalocyanine was a titanyl phthalocyanine represented by the chemical formula (CG1) described in the embodiment and having a Y-type crystal structure (hereinafter sometimes referred to as a compound (CG1)). The X-type metal-free phthalocyanine was a metal-free phthalocyanine represented by the chemical formula (CG2) described in the embodiment and having an X-type crystal structure (hereinafter sometimes referred to as a compound (CG2)).

(Binder resin)
The polycarbonate resin (R1) described in the embodiment was prepared as a binder resin. The viscosity average molecular weight of the polycarbonate resin (R1) was 40000.

(Additive)
As additives, the compounds (1-P1), (1-P2), (1-P3), (1-P4), (2-P5) and (2-P6) described in the embodiment were prepared.

<Manufacture of photoconductor>
Each of the photoreceptors (A-1) to (A-29) and (B-1) to (B-7) was manufactured using a material for forming the photosensitive layer.

(Manufacture of photoconductor (A-1))
In the container, 3 parts by mass of the compound (CG1) as the charge generating agent, 150 parts by mass of the compound (12-HT1) as the hole transporting agent, 75 parts by mass of the compound (ET1) as the electron transporting agent, and as the binder resin 100 parts by mass of the polycarbonate resin (R1), 20 parts by mass of the compound (1-P2) as an additive, and 800 parts by mass of tetrahydrofuran as a solvent were added. The contents of the container were mixed for 50 hours using a ball mill to disperse the material in the solvent. This obtained the coating liquid for photosensitive layers. The photosensitive layer coating solution was applied on a conductive substrate (aluminum drum-shaped support, 30 mm in diameter, 247.5 mm in total length) using a dip coating method. The coated photosensitive layer coating solution was dried with hot air at 120 ° C. for 60 minutes. Thereby, a single photosensitive layer (film thickness 28 μm) was formed on the conductive substrate. As a result, a photoreceptor (A-1) was obtained.

(Production of photoconductors (A-2) to (A-29) and (B-1) to (B-7))
Each of the photoreceptors (A-2) to (A-29) and (B-1) to (B-7) is the same as the production of the photoreceptor (A-1) except that the following points are changed. Manufactured. In the production of the photoreceptor (A-1), the compound (CG1) was used as a charge generator, but the photoreceptors (A-2) to (A-29) and (B-1) to (B-7) were used. In each production, charge generators of the types shown in Tables 1 to 3 were used. In the production of the photoreceptor (A-1), 150 parts by mass of the compound (12-HT1) was used as the hole transport agent, but the photoreceptors (A-2) to (A-29) and (B-1) In each production of (B-7), hole transport agents of the types and amounts shown in Tables 1 to 3 were used. In the production of the photoconductor (A-1), 75 parts by mass of the compound (ET1) was used as the electron transport agent, but the photoconductors (A-2) to (A-29) and (B-1) to (B) In each production of -7), the types and amounts of electron transport agents shown in Tables 1 to 3 were used. In the production of the photoreceptor (A-1), 20 parts by mass of the compound (1-P2) was used as an additive, but the photoreceptors (A-2) to (A-29) and (B-1) to (B-1) to (B) In each production of B-2) and (B-4) to (B-7), additives of the types and amounts shown in Tables 1 to 3 were used. No additive was used in the production of the photoreceptor (B-3).

<Measurement of optical response time>
The photoresponse times of the photoreceptors (A-1) to (A-29) and (B-1) to (B-7) were measured. The measurement environment of the photoresponsiveness time was an environment with a temperature of 25 ° C. and a relative humidity of 50% RH.

  With reference to FIG. 4, a method for measuring the photoresponse time of the photoreceptor 1 will be described. FIG. 4 shows an apparatus 50 for measuring the photoresponse time of the photoreceptor 1. The measurement device 50 includes a charging device 52, an exposure device 54, a transparent probe 56, and a potential detection device 58. As the measuring device 50, a drum sensitivity tester (manufactured by Gentec Corporation) was used. First, the photoreceptor 1 (specifically, any one of the photoreceptors (A-1) to (A-29) and (B-1) to (B-7)) was attached to the measuring device 50.

  The charging device 52 charged the surface 3a of the photosensitive layer 3 of the photoreceptor 1 to + 800V. As a result, the surface 3 a of the photosensitive layer 3 was charged to +800 V at the charging position A. The charging position A was a position where the charging device 52 and the surface 3 a of the photosensitive layer 3 were in contact with each other.

  The photosensitive member 1 was rotated in the direction from the charging position A to the exposure position B (the direction indicated by the solid line arrow in FIG. 4), and the surface 3 a of the charged photosensitive layer 3 was moved to the exposure position B. The exposure position B was a position where pulsed light was irradiated. After the movement, the rotation of the photosensitive member 1 was stopped and the position of the photosensitive member 1 was fixed. The measurement of the potential (surface potential) of the surface 3a of the photosensitive layer 3 was performed with the photosensitive member 1 fixed. At the exposure position B, the surface 3a of the photosensitive layer 3 charged with the exposure device 54 was irradiated with pulsed light (wavelength 780 nm, half width 40 microseconds). The light intensity of the pulsed light was set to an intensity at which the surface potential of the photosensitive layer 3 changed from +800 V to +200 V 400 milliseconds after the pulsed light was applied to the surface 3 a of the photosensitive layer 3 charged to +800 V. The pulsed light was irradiated once. That is, one pulse was irradiated. A xenon flash lamp (“C4479” manufactured by Hamamatsu Photonics Co., Ltd.) was used as the light source of the exposure device 54. The wavelength and light intensity of the pulsed light were adjusted with an optical filter (not shown). Strictly speaking, the surface 3 a of the photosensitive layer 3 was charged to a value slightly larger than +800 V by the charging device 52. Next, when the surface potential of the photosensitive layer 3 was darkly attenuated to +800 V after a predetermined time, pulsed light was irradiated to the surface 3 a of the photosensitive layer 3 by the exposure device 54.

  The surface potential of the photosensitive layer 3 was measured with the transparent probe 56. The transparent probe 56 is installed on the optical axis of the pulsed light and transmits the pulsed light. In FIG. 4, a broken line arrow from the exposure device 54 to the photosensitive member 1 indicates the optical axis of the pulsed light. A probe (“3629A” manufactured by Trek Japan Co., Ltd.) was used as the transparent probe 56.

  The potential detection device 58 was electrically connected to the transparent probe 56. The surface potential of the photosensitive layer 3 for each time measured by the transparent probe 56 was obtained by the potential detector 58. Thereby, an attenuation curve of the surface potential of the photosensitive layer 3 was obtained. From the obtained attenuation curve, a time τ was obtained from the time when the surface 3a of the photosensitive layer 3 was irradiated with the pulsed light until the surface potential of the photosensitive layer 3 was attenuated from + 800V to + 400V. The obtained time τ was defined as a light response time. The method for measuring the photoresponse time of the photoreceptor 1 has been described above with reference to FIG. Tables 1 to 3 show the measured photoresponse times of the photoreceptors.

<Image evaluation: Image defects caused by exposure memory>
It was evaluated for each of the photoreceptors (A-1) to (A-29) and (B-1) to (B-7) whether or not image defects due to the exposure memory were suppressed. Evaluation of image defects caused by the exposure memory was performed in an environment of a temperature of 10 ° C. and a relative humidity of 15% RH.

  The photoconductor was mounted on an evaluation machine. As an evaluation machine, a modified machine of a color image forming apparatus (“FS-C5250DN” manufactured by Kyocera Document Solutions Inc.) was used. The remodeling points of the modified machine were that the scorotron charger was changed to a charging roller, the cleaning blade was removed, and the static elimination unit (specifically, the static elimination lamp) was removed. That is, this evaluation machine was provided with a charging roller as a charging unit. Further, this evaluator did not include a static elimination unit and a cleaning blade as a cleaning unit. The charging potential was set to + 700V. The peripheral speed of the photoreceptor was adjusted so that the process time between exposure and development was 75 milliseconds.

  With reference to FIG. 5, an evaluation image 70 used for evaluating an image defect caused by the exposure memory will be described. FIG. 5 shows an evaluation image 70. The evaluation image 70 includes a first area 72 and a second area 74. The first area 72 corresponds to an area of an image formed on the first circumference of the image carrier. The first area 72 includes a first image 76. The first image 76 is composed of a donut-shaped solid image (image density 100%). This solid image is composed of a set of two concentric circles. The second area 74 corresponds to an area of an image formed on the second circumference of the image carrier. The second area 74 includes a second image 78. The second image 78 is composed of an entire halftone image (image density 40%).

  Next, with reference to FIG. 6, an image 80 in which an image defect caused by the exposure memory has occurred will be described. FIG. 6 shows an image 80 in which an image defect due to the exposure memory has occurred. The image 80 includes the first area 72, the second area 74, the first image 76, and the second image 78 described in the evaluation image 70. When the image for evaluation 70 is printed and an image defect caused by the exposure memory occurs, the second image 78 should be printed in the second area 74, and the ghost is included in the second image 78 in the second area 74. Image G appears. The image density of the ghost image G is higher than that of the second image 78. The ghost image G is an image defect caused by the exposure memory, which is darker than the design image density reflecting the first image 76 of the exposure area of the first area 72.

  First, an image (print pattern image with a printing rate of 4%) was printed at intervals of 15 seconds on 2000 recording media (A4 size paper) using an evaluation machine. After printing on 2,000 recording media, the evaluation image 70 shown in FIG. 5 was printed on one recording medium (A4 size paper). The printed evaluation image 70 was observed with the naked eye, and it was confirmed whether or not an image defect caused by the exposure memory occurred. Specifically, it was confirmed whether or not a ghost image G corresponding to the first image 76 occurred in the second region 74 of the evaluation image 70. Based on the observation results of the evaluation image 70, image defects caused by the exposure memory were evaluated based on the following criteria. The evaluation results are shown in Tables 4-6. In addition, it evaluated that the image defect resulting from exposure memory was not suppressed to the photoreceptor with evaluation D.

(Evaluation criteria for image defects caused by exposure memory)
Evaluation A: The ghost image G was not observed.
Evaluation B: A ghost image G was slightly observed.
Evaluation C: Although a ghost image G was observed, it was a level with no practical problem.
Evaluation D: The ghost image G was clearly observed, which was a practically problematic level.

<Evaluation of ozone resistance>
Ozone resistance was evaluated for each of the photoreceptors (A-1) to (A-29) and (B-1) to (B-7). First, in a normal environment (atmosphere, temperature 25 ° C. and relative humidity 50% RH), using a drum sensitivity tester (manufactured by Gentec Co., Ltd.), the photoreceptor is adjusted so that the surface potential of the photoreceptor becomes + 700V. Charged. Light (light energy 0.4 μJ / cm ² , wavelength 780 nm) was irradiated on the surface of the charged photoreceptor. The surface potential of the exposed area of the photoreceptor was measured when 80 milliseconds had elapsed from the start of light irradiation. The measured surface potential of the exposed area was defined as the initial post-exposure potential (V _L1 , unit: + V). Subsequently, the photoreceptor was allowed to stand for 6 hours in a dark environment (ozone concentration 10 ppm, temperature 25 ° C. and relative humidity 50% RH). This exposed the photoreceptor to ozone. After 6 hours of ozone exposure, the photoreceptor was removed from the dark environment and the photoreceptor was allowed to stand for 30 minutes in a normal environment. Next, the photoreceptor was charged using a drum sensitivity tester (Gentec Co., Ltd.) in a normal environment so that the surface potential of the photoreceptor was + 700V. Light (light energy 0.4 μJ / cm ² , wavelength 780 nm) was irradiated on the surface of the charged photoreceptor. The surface potential of the exposed area of the photoreceptor was measured when 80 milliseconds had elapsed from the start of light irradiation. The measured surface potential of the exposed region was defined as ozone exposure-post-exposure potential (V _L2 , unit: + V). The value “V _L2 −V _L1 ” was determined from the measured initial post-exposure potential (V _L1 ) and ozone exposure−post-exposure potential (V _L2 ). The values “V _L2 -V _L1 ” of each photoconductor are shown in Tables 4 to 6. The smaller the value “V _L2 −V _L1 ”, the better the ozone resistance of the photoreceptor. A photoconductor having a value “V _L2 −V _L1 ” of 30 V or higher was evaluated as having poor ozone resistance (indicated by x in Tables 4 to 6).

<Evaluation of repetitive characteristics>
The repetitive characteristics of the photoreceptors were evaluated for each of the photoreceptors (A-1) to (A-29) and the photoreceptors (B-1) to (B-7). The evaluation of the repetition characteristics was performed in an environment of a temperature of 10 ° C. and a relative humidity of 15% RH. The photoconductor was mounted on an evaluation machine. The evaluation machine used in the evaluation of the repetition characteristics was the same as that used in the evaluation of the image defect caused by the exposure memory. The peripheral speed of the photoreceptor was adjusted so that the process time between exposure and development was 70 milliseconds.

The charging potential of the photoreceptor was set to + 700V. The set charging potential was V _A (unit: + V). Using an evaluation machine, images (print pattern images with a printing rate of 4%) were continuously printed on 3000 recording media (A4 size paper). Immediately after printing on 3000 recording media, a blank image was printed on one recording medium (A4 size paper) using an evaluator. When a blank paper image (image corresponding to the non-exposed area) was printed, the surface potential of the non-exposed area of the photoreceptor after exposure was measured. The measured surface potential of the non-exposed area was defined as V _B (unit: + V). The value “V _A −V _B ” was determined from the set charging potential (V _A ) and the surface potential (V _B ) of the non-exposed area. Tables 4 to 6 show values “V _A −V _B ” of the respective photosensitive members. The smaller the value “V _A −V _B ”, the better the repeatability of the photoreceptor. _A photoconductor having a value “V _A −V _B ” of 40 V or more was evaluated as having poor repeatability of the photoconductor (indicated by x in Tables 4 to 6).

  In Tables 1 to 3, CGM, HTM, ETM, parts, wt%, CG2 and CG1 are, respectively, a charge generating agent, a hole transporting agent, an electron transporting agent, parts by mass, mass%, an X-type metal-free phthalocyanine and Y-type titanyl phthalocyanine is shown. In addition, the type of the hole transporting agent “12-HT2 / 12-HT1” and the amount of the hole transporting agent “60/60” of the photoreceptor (A-13) shown in Table 2 are 60 It shows that the compound (12-HT2) of a mass part and the compound (12-HT1) of 60 mass parts were used. The type of the hole transport agent “12-HT1 / 12-HT8” and the amount of the hole transport agent “60/60” of the photoreceptor (A-19) shown in Table 2 is 60 parts by mass as the hole transport agent. The compound (12-HT1) and 60 parts by mass of the compound (12-HT8) were used. The type of the hole transport agent “12-HT1 / 12-HT9” and the amount of the hole transport agent “60/60” of the photoreceptor (A-20) shown in Table 2 is 60 parts by mass as the hole transport agent. The compound (12-HT1) and 60 parts by mass of the compound (12-HT9) were used. The type of the hole transport agent “12-HT1 / 13-HT12” and the amount of the hole transport agent “60/60” of the photoreceptor (A-23) shown in Table 3 is 60 parts by mass as the hole transport agent. The compound (12-HT1) and 60 parts by mass of the compound (13-HT12) were used.

  In Tables 1 to 3, “HTM content” indicates the content of the hole transport agent relative to the mass of the photosensitive layer. The content of the hole transport agent with respect to the mass of the photosensitive layer is calculated by the formula “content ratio (unit: mass%) = 100 × amount of hole transport agent (unit: parts by mass) / [amount of charge generating agent (unit: (Mass part) + amount of hole transport agent (unit: mass part) + amount of electron transport agent (unit: mass part) + amount of binder resin (unit: mass part) + amount of additive (unit: mass part) ] ”.

In Tables 1 to 3, “ratio m _HTM / m _ETM ” indicates the ratio m _HTM / m _ETM of the mass m _HTM of the hole transport agent to the mass m _ETM of the electron transport agent. The ratio m _HTM / m _ETM was determined from the calculation formula “ratio m _HTM / m _ETM = amount of hole transport agent (unit: part by mass) / amount of electron transport agent (unit: part by mass)”.

Each of the photoconductors (A-1) to (A-29) was provided with a conductive substrate and a single photosensitive layer. The photosensitive layer contained a charge generating agent, a hole transporting agent, an electron transporting agent, a binder resin, and an additive. The optical response time was 0.05 milliseconds or more and 0.85 milliseconds or less. Each photosensitive layer of the photoreceptors (A-1) to (A-29) has, as a hole transport agent, compounds (11-HT6), (11-HT7), (12-HT1), (12-HT2). , (12-HT3), (12-HT4), (12-HT8), (12-HT9), (13-HT10), (13-HT12), (14-HT5), (15-HT13), ( 16-HT11), (17-HT16) and (18-HT17) were contained. The molecular weights of these compounds which are hole transporting agents were all 750 or less. The ratio m _HTM / m _ETM mass m _HTM of the hole transport agent to the mass m _ETM of the electron transport agent, was 1.2 to 4.0. Each photosensitive layer of the photoreceptors (A-1) to (A-29) has, as additives, compounds (1-P1), (1-P2), (1-P3), (1-P4), ( 2-P5) and (2-P6). Each of these compounds as additives was a compound included in the general formula (1) or (2). Therefore, as shown in Tables 4 to 6, in the photoconductors (A-1) to (A-29), the evaluation of the image defect due to the exposure memory is A to C, and the image defect due to the exposure memory. Was suppressed. In the photoconductors (A-1) to (A-29), the value of V _L2 -V _L1 was less than 30 V, and the ozone resistance of the photoconductor was good. In the photoconductors (A-1) to (A-29), the value of V _A -V _B was less than 40 V, and the repetitive characteristics of the photoconductor were good.

On the other hand, in each of the photoreceptors (B-1) and (B-2), the photoresponse time was more than 0.85 milliseconds. In the photosensitive member (B-1), the ratio m _HTM / m _ETM mass m _HTM of the hole transport agent to the mass m _ETM of the electron transport agent is less than 1.2. Therefore, as shown in Table 6, in each of the photosensitive members (B-1) and (B-2), the evaluation of the image defect due to the exposure memory is D, and the image defect due to the exposure memory is suppressed. It wasn't. In the photoreceptors (B-1) and (B-2), the value of V _A -V _B was 40 V or more, and the repeatability of the photoreceptor was inferior.

The photosensitive layer of the photoreceptor (B-3) did not contain an additive. Therefore, as shown in Table 6, in the photoreceptor (B-3), the value of V _L2 −V _L1 was 30 V or more, and the ozone resistance of the photoreceptor was inferior. Further, in the photoreceptor (B-3), the value of V _A −V _B was 40 V or more, and the repeatability of the photoreceptor was inferior.

The photosensitive layer of the photoreceptor (B-4) contained the compound (HT14) as a hole transport agent. However, the molecular weight of compound (HT14) was greater than 750. Therefore, as shown in Table 6, in the photoreceptor (B-4), the value of V _L2 -V _L1 was 30 V or more, and the ozone resistance of the photoreceptor was inferior. In the photoreceptor (B-4), the value of V _A −V _B was 40 V or more, and the repetitive characteristics of the photoreceptor were inferior.

In the photoreceptor (B-5), the optical response time was more than 0.85 milliseconds. Therefore, as shown in Table 6, in the photoreceptor (B-5), the evaluation of the image defect due to the exposure memory was D, and the image defect due to the exposure memory was not suppressed. In the photoreceptor (B-5), the value of V _A -V _B was 40 V or more, and the repetitive characteristics of the photoreceptor were inferior.

In the photoreceptor (B-6), the ratio m _HTM / m _ETM of the mass transfer agent mass m _{HTM to} the electron transfer agent mass m _ETM was _greater than 4.0. Therefore, as shown in Table 6, in the photoreceptor (B-6), the value of V _L2 −V _L1 was 30 V or more, and the ozone resistance of the photoreceptor was inferior. In the photoreceptor (B-6), the value of V _A -V _B was 40 V or more, and the repeatability of the photoreceptor was inferior.

In the photosensitive member (B-7), the ratio m _HTM / m _ETM mass m _HTM of the hole transport agent to the mass m _ETM of the electron transport agent was greater than 4.0. In the photoreceptor (B-7), the photoresponse time could not be measured because the photosensitive layer was crystallized. As shown in Table 6, since the photosensitive layer was crystallized, the value of V _L2 -V _{L1 and} the value of V _A -V _B could not be measured in the photoconductor (B-7), and the exposure memory was not used. The resulting image failure could not be evaluated.

  From the above, it has been shown that the photoreceptor according to the present invention can achieve suppression of image defects caused by exposure memory, improvement of repetition characteristics, and improvement of ozone resistance. Further, it has been shown that the process cartridge and the image forming apparatus according to the present invention can suppress the occurrence of image defects due to the exposure memory, the deterioration of the repetition characteristics, and the influence of ozone.

  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 for forming an image on a recording medium.

1: Electrophotographic photosensitive member 2: Conductive substrate 3: Photosensitive layer 3 a: Surface 30 of the photosensitive layer: Image carrier 42: Charging unit 44: Exposure unit 46: Developing unit 48: Transfer unit 90: Image forming apparatus

Claims (13)

An electrophotographic photosensitive member comprising a conductive substrate and a single photosensitive layer,
The photosensitive layer contains a charge generating agent, a hole transport agent, an electron transport agent, a binder resin, and an additive,
The optical response time is 0.05 milliseconds or more and 0.85 milliseconds or less,
The photoresponse time is a time from when the surface of the photosensitive layer charged with +800 V is irradiated with pulsed light having a wavelength of 780 nm until the surface potential of the photosensitive layer decays from +800 V to +400 V,
The intensity of the pulsed light is an intensity at which the surface potential of the photosensitive layer is changed from +800 V to +200 V after 400 milliseconds from the irradiation of the surface of the photosensitive layer charged with +800 V with the pulsed light,
The hole transport agent has a molecular weight of 750 or less,
The ratio m _HTM / m _ETM mass m _HTM of the hole transport agent to the mass m _ETM of the electron transport agent is approximately 1.2 to 4.0,
The additive is an electrophotographic photosensitive member containing at least one of the compounds represented by the general formulas (1) and (2).

(In the general formula (1),
R ^1A , R ^1B , R ^1C , R ^1D , R ^1E , R ^2A , R ^2B , R ^2C , R ^2D and R ^2E are each independently a hydrogen atom, halogen atom, hydroxyl group, cyano group, nitro group, An amino group, an alkyl group having 1 to 12 carbon atoms which may have a substituent, an alkoxy group having 1 to 12 carbon atoms which may have a substituent, and a carbon which may have a substituent An aryl group having 6 to 30 atoms, a cycloalkyl group having 3 to 12 carbon atoms which may have a substituent, or a heterocyclic group which may have a substituent;
R ³ represents an alkylene group having 1 to 12 carbon atoms which may have a substituent,
p represents 0 or 1,
In the general formula (2),
R ⁴ , R ⁵ and R ⁶ are each independently a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amino group, an alkyl group having 1 to 12 carbon atoms which may have a substituent, or a substituent. An alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 30 carbon atoms that may have a substituent, or 3 or more carbon atoms that may have a substituent Represents 12 or less cycloalkyl groups,
q ₁ and q ₂ each independently represents an integer of 0 or more and 5 or less. )   2. The electrophotographic photosensitive member according to claim 1, wherein a content ratio of the hole transport agent with respect to a mass of the photosensitive layer is 33% by mass or more and 60% by mass or less. In the general formula (1),
R ^1A , R ^1B , R ^1C , R ^1D and R ^1E each represent a hydrogen atom;
R ^2A , R ^2B , R ^2C , R ^2D and R ^2E each independently represent a hydrogen atom or an aryl group having 6 to 10 carbon atoms,
R ³ represents an alkylene group having 1 to 6 carbon atoms,
p represents 0 or 1,
In the general formula (2),
R ⁴ and R ⁵ each independently represents an alkyl group having 1 to 6 carbon atoms,
R ⁶ represents an aryl group having 6 to 10 carbon atoms, which may have an alkyl group having 1 to 6 carbon atoms,
The electrophotographic photosensitive member according to claim _1, wherein q ₁ and q ₂ each independently represent 0 or 1. At least one of the compounds represented by the general formulas (1) and (2) is represented by the chemical formulas (1-P1), (1-P2), (1-P3), (1-P4), (2 The electrophotographic photoreceptor according to any one of claims 1 to 3, which is at least one of the compounds represented by -P5) and (2-P6).

The electron according to any one of claims 1 to 4, wherein the hole transport agent includes at least one of compounds represented by general formulas (11) to (18) and having a molecular weight of 750 or less. Photoconductor.

(In the general formula (11), Q ¹ , Q ² , Q ³ and Q ⁴ each independently represents an alkyl group having 1 to 6 carbon atoms, and b ₁ , b ₂ , b ₃ and b _4. Each independently represents an integer of 0 to ₅ , b ₅ represents 0 or 1,
In the general formula (12), Q ²¹ and Q ²⁸ are each independently a phenyl group optionally having an alkyl group having 1 to 6 carbon atoms, a hydrogen atom, or an alkyl having 1 to 6 carbon atoms. A group or an alkoxy group having 1 to 6 carbon atoms, Q ²² and Q ²⁹ are each independently an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group; Q ²³ , Q ²⁴ , Q ²⁵ , Q ²⁶ and Q ²⁷ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group And adjacent two of Q ²³ , Q ²⁴ , Q ²⁵ , Q ²⁶ and Q ²⁷ may be bonded to each other to form a ring, and d ₁ and d ₂ are each independently 0 or more and 2 represents an integer, d ₃ and d ₄ are each independently table an integer of 0 to 5 ,
In the general formula (13), Q ³¹ , Q ³² , Q ³³ and Q ³⁴ each independently represent an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, e ₁ , e ₂ , e ₃ and e ₄ each independently represents an integer of 0 or more and 5 or less, e ₅ represents 2 or 3,
In the general formula (14), Q ⁴¹ , Q ⁴² and Q ⁴³ each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms or a phenyl group, and f ₁ , f ₂ and f ₃ each independently represents an integer of 0 or more and 5 or less, and Q ⁴⁴ , Q ⁴⁵ and Q ⁴⁶ each independently have an alkyl group having 1 to 6 carbon atoms. And may represent a phenyl group, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, wherein f ₄ , f ₅ and f ₆ are each independently 0 or 1 Represent,
In the general formula (15), Q ⁵¹ , Q ⁵² , Q ⁵³ , Q ⁵⁴ , Q ⁵⁵ and Q ⁵⁶ each independently have 2 or more and 4 or less carbon atoms which may have one or more phenyl groups. An alkenyl group, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an alkoxy group having 1 to 6 carbon atoms, h ₃ and h ₆ each independently represents an integer of 0 to 4 , H ₁ , h ₂ , h ₄ and h ₅ each independently represents an integer of 0 or more and 5 or less,
In the general formula (16), Q ⁶¹ , Q ⁶² , Q ⁶³ and Q ⁶⁴ each independently represents an alkyl group having 1 to 6 carbon atoms, and k ₁ , k ₂ , k ₃ and k ₄ are Each independently represents an integer from 0 to 5,
In the general formula (17), Q ⁷¹ , Q ⁷² , Q ⁷³ , Q ⁷⁴ and Q ⁷⁵ are each independently an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, Represents an aryl group having 6 to 14 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, m ₁ represents an integer of 0 to 5, and n ₁ and n ₂ are each independently 0 or more. Represents an integer of 2 or less, except that n ₁ represents 1 and n ₂ represents 1.
In the general formula (18), R ⁸¹ and R ⁸² each independently represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 14 carbon atoms, provided that R ⁸¹ and R ⁸² R ⁸³ is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxy group having 7 to 20 carbon atoms, unless both represent an aryl group having 6 to 14 carbon atoms. The following aralkyl groups or aryl groups having 6 to 14 carbon atoms are represented, p ₁ represents an integer of 0 or more and 2 or less, and p ₂ represents an integer of 0 or more and 5 or less. ) In the general formula (11), Q ¹ , Q ² , Q ³ and Q ⁴ each independently represents an alkyl group having 1 to 3 carbon atoms, and b ₁ , b ₂ , b ₃ and b ₄ are Each independently represents 0 or 1, b ₅ represents 0 or 1,
In the general formula (12), Q ²¹ and Q ²⁸ each independently represent a phenyl group which may have an alkyl group having 1 to 6 carbon atoms, or a hydrogen atom, and Q ²² and Q ²⁹ are Each independently represents an alkyl group having 1 to 6 carbon atoms, and Q ²³ , Q ²⁴ , Q ²⁵ , Q ²⁶ and Q ²⁷ are each independently a hydrogen atom, an alkyl having 1 to 6 carbon atoms. Or an alkoxy group having 1 to 6 carbon atoms, and adjacent two of Q ²³ , Q ²⁴ , Q ²⁵ , Q ²⁶ and Q ²⁷ are bonded to each other to form a cyclohexane having 5 to 7 carbon atoms. An alkane may be formed, d ₁ and d ₂ each independently represent an integer of 0 or more and 2 or less, d ₃ and d ₄ each independently represent 0 or 1,
In the general formula (13), Q ³¹ , Q ³² , Q ³³ and Q ³⁴ each independently represents an alkyl group having 1 to 6 carbon atoms, and e ₁ , e ₂ , e ₃ and e ₄ are Each independently represents 0 or 1, e ₅ represents 2 or 3,
In the general formula (14), Q ⁴¹ , Q ⁴² and Q ⁴³ each independently represents an alkyl group having 1 to 6 carbon atoms, and f ₁ , f ₂ and f ₃ are each 0 or 1 Q ⁴⁴ , Q ⁴⁵ and Q ⁴⁶ each represents a hydrogen atom, f ₄ , f ₅ and f ₆ each represents 0,
In the general formula (15), Q ⁵¹ , Q ⁵² , Q ⁵³ , Q ⁵⁴ , Q ⁵⁵ and Q ⁵⁶ each independently represents an alkyl group having 1 to 6 carbon atoms, and h ₃ and h ₆ are Each represents 0, h ₁ , h ₂ , h ₄ and h ₅ each independently represents an integer of 0 or more and 2 or less,
In the general formula (16), Q ⁶¹ , Q ⁶² , Q ⁶³ and Q ⁶⁴ each independently represents an alkyl group having 1 to 3 carbon atoms, and k ₁ , k ₂ , k ₃ and k ₄ are Each independently represents 0 or 1,
In the general formula (17), Q ⁷¹ , Q ⁷² , Q ⁷³ , Q ⁷⁴ and Q ⁷⁵ each independently represents an alkyl group having 1 to 6 carbon atoms, and m ₁ represents 1 or 2. , N ₁ and n ₂ each represents 0;
In the general formula (18), R ⁸¹ and R ⁸² each independently represents an alkyl group having 1 to 3 carbon atoms or a phenyl group, provided that both R ⁸¹ and R ⁸² represent a phenyl group. Except for the above, p ₁ represents 1 or 2, and p ₂ represents 0. At least one of the compounds represented by the general formulas (11) to (18) and having a molecular weight of 750 or less is represented by the chemical formulas (11-HT6), (11-HT7), (12-HT1), (12 -HT2), (12-HT3), (12-HT4), (12-HT8), (12-HT9), (13-HT10), (13-HT12), (14-HT5), (15-HT13) ), (16-HT11), (17-HT16) and (18-HT17). The electrophotographic photoreceptor according to claim 5 or 6, which is at least one of the compounds represented by (18-HT17).

  At least one of the compounds represented by the general formulas (11) to (18) and having a molecular weight of 750 or less is the chemical formula (11-HT6), (11-HT7), (13-HT10), ( The electrophotography according to claim 7, which is at least one of the compounds represented by (13-HT12), (14-HT5), (16-HT11), (17-HT16) and (18-HT17). Photoconductor.   At least one of the compounds represented by the general formulas (11) to (18) and having a molecular weight of 750 or less is at least one of the compounds represented by the chemical formulas (17-HT16) and (18-HT17). The electrophotographic photosensitive member according to claim 7 or 8, which is a seed.   A process cartridge comprising the electrophotographic photosensitive member according to claim 1. An image carrier;
A charging unit that charges the surface of the image carrier;
An exposure unit that exposes the surface of the charged image carrier to form an electrostatic latent image on the surface of the image carrier;
A developing unit for developing the electrostatic latent image as a toner image;
An image forming apparatus comprising: a transfer unit that transfers the toner image from the image carrier to a transfer target;
The charging unit charges the surface of the image carrier to a positive polarity,
The image forming apparatus according to claim 1, wherein the image carrier is the electrophotographic photosensitive member according to claim 1.   The image forming apparatus according to claim 11, wherein a time from when a predetermined portion on the surface of the image carrier is exposed by the exposure unit to development by the developing unit is 100 milliseconds or less.   13. The image forming apparatus according to claim 11, wherein a region of the surface of the image carrier that has finished transferring the toner image to the transfer target is charged again by the charging unit without being neutralized. .

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