CN113994268A

CN113994268A - Electrophotographic photoreceptor, process cartridge, and image forming apparatus

Info

Publication number: CN113994268A
Application number: CN202080045413.5A
Authority: CN
Inventors: 岩下裕子; 浜崎一也
Original assignee: Kyocera Document Solutions Inc
Current assignee: Kyocera Document Solutions Inc
Priority date: 2019-06-24
Filing date: 2020-06-15
Publication date: 2022-01-28
Also published as: JP7215577B2; JPWO2020262069A1; WO2020262069A1

Abstract

An electrophotographic photoreceptor includes a conductive substrate and a photosensitive layer. The photosensitive layer is a single layer. The photosensitive layer contains a charge generator, a hole transporting agent, an electron transporting agent, a binder resin, and an n-type pigment. The binder resin contains a polyarylate resin. The polyarylate resin contains at least 1 repeating unit represented by the general formula (1) and at least 1 repeating unit represented by the general formula (2). In the general formula (1), a represents 1 or 2. In the general formula (2), X is a divalent group represented by the formula (X1), (X2), (X3), (X4) or (X5).

Description

Electrophotographic photoreceptor, process cartridge, and image forming apparatus

Technical Field

The invention relates to an electrophotographic photoreceptor, a process cartridge and an image forming apparatus.

Background

Electrophotographic photoreceptors are used as image carriers in electrophotographic image forming apparatuses (e.g., printers or multifunction machines). The electrophotographic photoreceptor includes a photosensitive layer. Examples of the electrophotographic photoreceptor include a single-layer type electrophotographic photoreceptor and a laminated type electrophotographic photoreceptor. The single-layer electrophotographic photoreceptor has a single photosensitive layer having a charge generating function and a charge transporting function. The photosensitive layer in the laminated electrophotographic photoreceptor contains a charge generation layer having a charge generation function and a charge transport layer having a charge transport function.

The electrophotographic photoreceptor in the image forming apparatus described in patent document 1 contains a bisphenol Z polycarbonate resin as a binder resin at least in its surface layer.

[ patent document ]

Patent document 1: japanese laid-open patent publication No. 8-234538

Disclosure of Invention

However, the inventors have found, through their studies, that the electrophotographic photoreceptor in the image forming apparatus described in patent document 1 is insufficient in terms of abrasion resistance and charging stability.

The present invention has been made in view of the above problems, and an object thereof is to provide an electrophotographic photoreceptor having excellent wear resistance and charging stability. Still another object of the present invention is to provide a process cartridge and an image forming apparatus which have excellent durability and can form a high-quality image by having the above-mentioned electrophotographic photoreceptor.

The electrophotographic photoreceptor of the present invention includes a conductive substrate and a photosensitive layer. The photosensitive layer is a single layer. The photosensitive layer contains a charge generator, a hole transporting agent, an electron transporting agent, a binder resin, and an n-type pigment. The binder resin contains a polyarylate resin. The polyarylate resin contains at least 1 repeating unit represented by the general formula (1) and at least 1 repeating unit represented by the general formula (2).

In the general formula (1), a represents 1 or 2. In the general formula (2), X is a divalent group represented by the chemical formula (X1), (X2), (X3), (X4) or (X5).

The process cartridge of the present invention includes the electrophotographic photoreceptor.

An image forming apparatus of the present invention includes an image carrier, a charging device, an exposure device, a developing device, and a transfer device. The image carrier is rotatably provided. The charging device charges the surface of the image carrier to a positive polarity. The exposure device irradiates the charged surface of the image carrier with light to form an electrostatic latent image on the surface of the image carrier. The developing device develops the electrostatic latent image into a toner image. The transfer device transfers the toner image from the image bearing member to a transfer object. The image bearing member is the electrophotographic photoreceptor.

[ Effect of the invention ]

The electrophotographic photoreceptor of the present invention has excellent abrasion resistance and charging stability. Further, the process cartridge and the image forming apparatus of the present invention are provided with the above-mentioned electrophotographic photoreceptor, have excellent durability and can form a high-quality image.

Drawings

Fig. 1 is a partial sectional view of an electrophotographic photoreceptor according to an embodiment of the present invention.

Fig. 2 is a partial sectional view of the electrophotographic photoreceptor according to the embodiment of the present invention.

Fig. 3 is a partial sectional view of the electrophotographic photoreceptor according to the embodiment of the present invention.

Fig. 4 is a cross-sectional view of an example of an image forming apparatus.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments in any way. The present invention can be implemented by appropriately changing the range of the object. Note that, although the description thereof may be omitted as appropriate, the gist of the present invention is not limited thereto. Hereinafter, the compound and its derivatives may be collectively referred to by adding "class" to the compound name. When a "class" is added to a compound name to indicate a polymer name, the repeating unit indicating the polymer is derived from the compound or a derivative thereof.

First, the substituents used in the present specification will be described. Halogen atoms (halo groups) are, for example: fluorine atom (fluoro group), chlorine atom (chloro group), bromine atom (bromo group), and iodine atom (iodo group).

Unless otherwise indicated, C1-C10 alkyl, C1-C8 alkyl, C1-C6 alkyl, C1-C5 alkyl, C1-C4 alkyl and C1-C3 alkyl are all straight or branched chain and unsubstituted. C1-C10 alkyl is, for example: methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylpropyl group, 2-ethylpropyl group, 1-dimethylpropyl group, 1, 2-dimethylpropyl group, 2, 2-dimethylpropyl group, 1, 2-dimethylpropyl group, n-hexyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 1-dimethylbutyl group, 1, 2-dimethylbutyl group, 1, 3-dimethylbutyl group, 2, 2-dimethylbutyl group, 2, 3-dimethylbutyl group, 3-dimethylbutyl group, 1, 2-trimethylpropyl group, 1,2, 2-trimethylpropyl group, 1-ethylbutyl, 2-ethylbutyl and 3-ethylbutyl, straight-chain and branched-chain heptyl, straight-chain and branched-chain octyl, straight-chain and branched-chain nonyl and straight-chain and branched-chain decyl. Examples of C1-C8 alkyl, C1-C6 alkyl, C1-C5 alkyl, C1-C4 alkyl and C1-C3 alkyl are each radicals having the corresponding number of carbon atoms in the case of C1-C10 alkyl.

Unless otherwise indicated, C1-C8 alkoxy, C1-C6 alkoxy, C1-C4 alkoxy and C1-C3 alkoxy are linear or branched and are unsubstituted. C1-C6 alkoxy is, for example: methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, 1-methylbutoxy, 2-methylbutoxy, 3-methylbutoxy, 1-ethylpropoxy, 2-ethylpropoxy, 1-dimethylpropoxy, 1, 2-dimethylpropoxy, 2-dimethylpropoxy, 1, 2-dimethylpropoxy, n-hexoxy, 1-methylpentoxy, 2-methylpentoxy, 3-methylpentoxy, 4-methylpentoxy, 1-dimethylbutoxy, 1, 2-dimethylbutoxy, 1, 3-dimethylbutoxy, 2-dimethylbutoxy, 2, 3-dimethylbutoxy, 3-dimethylbutoxy, n-butoxy, 2-methylbutoxy, 3-methylpropoxy, 2-methylpropoxy, 1, 2-dimethylbutoxy, 2-dimethylbutoxy, 3-dimethylbutoxy, 1,1, 2-trimethylpropoxy, 1,2, 2-trimethylpropoxy, 1-ethylbutoxy, 2-ethylbutoxy, 3-ethylbutoxy, linear and branched heptyloxy and linear and branched octyloxy. Examples of C1-C6 alkoxy, C1-C4 alkoxy and C1-C3 alkoxy are the radicals having the corresponding number of carbon atoms in the examples of C1-C8 alkoxy, respectively.

Unless otherwise indicated, aryl, C6-C14 aryl, and C6-C10 aryl are unsubstituted. Aryl is, for example, C6-C14 aryl. C6-C14 aryl is, for example: phenyl, naphthyl, indacenyl, biphenylene, acenaphthylene, anthryl and phenanthryl. C6-C10 aryl is, for example: phenyl and naphthyl.

Unless otherwise indicated, C6-C14 aryloxy is unsubstituted. C6-C14 aryloxy is for example: phenoxy, naphthoxy, indacenyloxy (indacenyloxy), biphenylyloxy (biphenylyloxy), acenaphthenyloxy (acenaphthenyloxy), anthracenyloxy, phenanthreneoxy, and fluorenyloxy groups.

Unless otherwise indicated, C2-C6 alkenyl is straight-chain or branched-chain and is unsubstituted. The C2-C6 alkenyl group has 1 to 3 double bonds. C2-C6 alkenyl is, for example: ethenyl, propenyl, butenyl, butadienyl, pentenyl, hexenyl, hexadienyl, and hextripentyl.

Unless otherwise indicated, heterocyclyl and C3-C14 heterocyclyl are both unsubstituted. Heterocyclyl is for example C3-C14 heterocyclyl. C3-C14 heterocyclyl is, for example: piperidinyl, piperazinyl, (2-or 3-) morpholinyl, thiophenyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl, isothiazolyl, isoxazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, furazanyl, pyranyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, 1H-indazolyl, isoindolyl, benzopyranyl, quinolinyl, isoquinolinyl, purinyl, pteridinyl, triazolyl, tetrazolyl, 4H-quinolizinyl, naphthyridinyl, benzofuranyl, 1, 3-benzodioxolyl, benzoxazolyl, benzothiazolyl, benzimidazolyl, carbazolyl, phenanthridinyl, acridinyl, phenazinyl, and phenanthrolinyl.

Unless otherwise indicated, aralkyl, C7-C20 aralkyl, and C7-C12 aralkyl are unsubstituted. Aralkyl is for example C7-C20 aralkyl. C7-C20 aralkyl is, for example, C1-C6 alkyl having C6-C14 aryl substituents. C7-C12 aralkyl is, for example, C1-C6 alkyl with a phenyl substituent.

Unless otherwise indicated, both the C7-C20 aralkyloxy and the C7-C10 aralkyloxy are unsubstituted. C7-C20 aralkyloxy is, for example, C1-C6 alkoxy having C6-C14 aryl substituents. C7-C10 aralkyl is, for example, C1-C4 alkoxy with a phenyl substituent. As described above, the substituents used in the present specification are illustrated.

< electrophotographic photoreceptor >

The present embodiment relates to an electrophotographic photoreceptor (hereinafter, may be referred to as a photoreceptor). The structure of the photoreceptor 1 according to the present embodiment will be described below with reference to fig. 1 to 3. Fig. 1 to 3 each show a partial sectional view of the photoreceptor 1.

As shown in fig. 1, the photoreceptor 1 includes, for example, a conductive substrate 2 and a photosensitive layer 3. The photosensitive layer 3 is a single layer. The photoreceptor 1 is a single-layer electrophotographic photoreceptor having a single photosensitive layer 3.

As shown in fig. 2, the photoreceptor 1 may also 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. 1, the photosensitive layer 3 may be directly on the conductive substrate 2. Alternatively, as shown in fig. 2, the photosensitive layer 3 may be provided on the conductive substrate 2 with the intermediate layer 4 interposed therebetween.

As shown in fig. 3, the photoreceptor 1 may include a conductive substrate 2, a photosensitive layer 3, and a protective layer 5. The protective layer 5 is provided on the photosensitive layer 3. As shown in fig. 1 and 2, the photosensitive layer 3 serves as the outermost surface layer of the photoreceptor 1. Alternatively, as shown in fig. 3, the protective layer 5 may be an outermost surface layer of the photoreceptor 1.

The photosensitive layer 3 contains a charge generator, a hole transporting agent, an electron transporting agent, a binder resin, and an n-type pigment.

The thickness of the photosensitive layer 3 is not particularly limited, but is preferably 5 μm to 100 μm, and more preferably 10 μm to 50 μm. As described above, the structure of the photoreceptor 1 is described with reference to fig. 1 to 3. The photoreceptor will be further described below.

(Binder resin)

The photosensitive layer contains a polyarylate resin as a binder resin. The polyarylate resin contains at least 1 repeating unit represented by the general formula (1) and at least 1 repeating unit represented by the general formula (2). Hereinafter, when the polyarylate resin contains at least 1 repeating unit represented by the general formula (1) and at least 1 repeating unit represented by the general formula (2), it may be referred to as a polyarylate resin (PA). The repeating units represented by the general formulae (1) and (2) may be referred to as repeating units (1) and (2), respectively.

In the general formula (1), a represents 1 or 2. In the general formula (2), X is a divalent group represented by the formula (X1), (X2), (X3), (X4) or (X5).

The polyarylate resin (PA) has a specific chemical structure. By containing the polyarylate resin (PA) in the photosensitive layer, the abrasion resistance of the photoreceptor can be improved. Further, the polyarylate resin (PA) has a specific chemical structure, and thus the density of the photosensitive layer can be increased. Therefore, a substance (e.g., gas) that lowers the charging potential is less likely to enter the photosensitive layer, and the charging stability of the photoreceptor is improved. In the present specification, the charge stability of the photoreceptor means: the characteristic that the charged potential of the photoreceptor is not easily lowered even when image printing is repeatedly performed using an image forming apparatus having the photoreceptor.

In the general formula (1), a preferably represents 2. In the general formula (2), X is preferably a divalent group represented by the formula (X1), (X3), (X4) or (X5).

Preferred examples of the repeating unit (1) include: repeating units represented by the formulae (1-1) and (1-2). Hereinafter, the repeating units represented by the chemical formulae (1-1) and (1-2) may be referred to as repeating units (1-1) and (1-2), respectively.

Preferable examples of the repeating unit (2) include: a repeating unit represented by the chemical formula (2-X1), (2-X2), (2-X3), (2-X4) and (2-X5). Hereinafter, the repeating units represented by chemical formulae (2-X1), (2-X2), (2-X3), (2-X4) and (2-X5) may be described as repeating units (2-X1), (2-X2), (2-X3), (2-X4) and (2-X5), respectively. Further preferable examples of the repeating unit (2) include: repeating units (2-X1), (2-X3), (2-X4) and (2-X5).

An example of the polyarylate resin (PA) is a polyarylate resin (hereinafter, referred to as polyarylate resin (V)) containing the repeating units (1 to 2) and (2 to X3). The polyarylate resin (V) is preferably: a polyarylate resin (hereinafter, referred to as polyarylate resin (V')) having only the repeating units (1-2) and (2-X3) in the repeating units.

Another example of the polyarylate resin (PA) is a polyarylate resin (hereinafter, referred to as polyarylate resin (IX)) containing the repeating units (1 to 2) and (2 to X5). The polyarylate resin (IX) is preferably: a polyarylate resin (hereinafter, referred to as polyarylate resin (IX')) having only the repeating units (1-2) and (2-X5) in the repeating units.

Another example of the polyarylate resin (PA) is a polyarylate resin (hereinafter, referred to as polyarylate resin (I)) containing the repeating units (1-2), (2-X1) and (2-X4).

Another example of the polyarylate resin (PA) is a polyarylate resin (hereinafter, referred to as polyarylate resin (II)) containing the repeating units (1-2), (2-X1) and (2-X3). The polyarylate resin (II) is preferably: a polyarylate resin (hereinafter, referred to as polyarylate resin (II')) having only the repeating units (1-2), (2-X1) and (2-X3) in the repeating units.

Another example of the polyarylate resin (PA) is a polyarylate resin (hereinafter, referred to as polyarylate resin (III)) containing the repeating units (1-2), (2-X4) and (2-X3).

Another example of the polyarylate resin (PA) is a polyarylate resin (hereinafter, referred to as polyarylate resin (VIII)) containing the repeating units (1-2), (2-X5) and (2-X3).

Another example of the polyarylate resin (PA) is a polyarylate resin (hereinafter, referred to as polyarylate resin (VI)) having the repeating units (1-2), (2-X5) and (2-X1).

Another example of the polyarylate resin (PA) is a polyarylate resin (hereinafter, referred to as polyarylate resin (X)) containing the repeating units (1-1), (2-X1) and (2-X3).

Another example of the polyarylate resin (PA) is a polyarylate resin (hereinafter, referred to as polyarylate resin (XII)) having the repeating units (1-1), (1-2), (2-X1) and (2-X3).

Preferred examples of the polyarylate resin (PA) are: polyarylate resins represented by chemical formulas (R1) to (R12) (hereinafter, sometimes referred to as polyarylate resins (R1) to (R12), respectively). In addition, in the chemical formulas (R1) to (R12), the right subscript number of each repeating unit means: the percentage (%) of the number of each repeating unit in the polyarylate resin with respect to the total number of the repeating units. The total number of repeating units in the polyarylate resin is the sum of the number of repeating units derived from bisphenol and the number of repeating units derived from dicarboxylic acid.

The polyarylate resin (PA) contains 1 or 2 kinds of repeating units (1). When the polyarylate resin (PA) contains 2 kinds of the repeating units (1), the ratio of the number of one repeating unit (1) to the total number of one repeating unit (1) and the other repeating unit (1) is preferably 10% or more and 90% or less, more preferably 30% or more and 70% or less, further preferably 40% or more and 60% or less, and particularly preferably 55% or more and 60% or less. In the case where the 2 kinds of repeating units (1) are the repeating units (1-1) and (1-2), one repeating unit (1) is the repeating unit (1-2), and the other repeating unit (1) is the repeating unit (1-1).

The polyarylate resin (PA) contains 1 or more and 5 or less kinds of repeating units (2). The polyarylate resin (PA) preferably contains at least 2 (for example, 2 or more and 5 or less) repeating units (2), and more preferably contains 2 repeating units (2). When the polyarylate resin (PA) contains 2 kinds of the repeating units (2), the ratio of the number of one repeating unit (2) to the total number of one repeating unit (2) and the other repeating unit (2) is preferably 10% or more and 90% or less, more preferably 30% or more and 80% or less, further preferably 50% or more and 80% or less, and particularly preferably 50% or more and 70% or less. In the case where the 2 kinds of repeating units (2) are the repeating units (2-X3) and (2-X4), one repeating unit (2) is the repeating unit (2-X3), and the other repeating unit (2) is the repeating unit (2-X4). In the case where the 2 kinds of repeating units (2) are the repeating units (2-X1) and (2-X3), one repeating unit (2) is the repeating unit (2-X3), and the other repeating unit (2) is the repeating unit (2-X1).

With respect to the ratio of the number of the above one repeating unit (1) and the ratio of the number of the above one repeating unit (2), the measurement of polyarylate resin (PA) was carried out using a proton nuclear magnetic resonance spectrometer¹H-NMR spectrum against the obtained¹The ratio can be obtained by calculating the ratio of characteristic peaks for each repeating unit in the H-NMR spectrum.

The polyarylate resin (PA) may contain only the repeating units (1) and (2) or may further contain another repeating unit. In the photosensitive layer, the binder resin may contain only 1 polyarylate resin (PA), or may contain 2 or more polyarylate resins (PA).

In the polyarylate resin (PA), the repeating units derived from bisphenol and the repeating units derived from dicarboxylic acid are adjacent to each other and bonded to each other. The repeating unit derived from bisphenol is, for example, the repeating unit (1). The repeating unit derived from a dicarboxylic acid is, for example, the repeating unit (2). The polyarylate resin (PA) may be, for example, a random copolymer, an alternating copolymer, a periodic copolymer, or a block copolymer.

The viscosity average molecular weight of the polyarylate resin (PA) is preferably 10,000 or more, more preferably 20,000 or more, further preferably 30,000 or more, further preferably 40,000 or more, and particularly preferably 50,000 or more. When the viscosity average molecular weight of the polyarylate resin (PA) is 10,000 or more, the abrasion resistance of the photoreceptor can be improved. On the other hand, the viscosity average molecular weight of the polyarylate resin (PA) is preferably 80,000 or less, and more preferably 70,000 or less. When the viscosity average molecular weight of the polyarylate resin (PA) is 80,000 or less, the polyarylate resin (PA) is easily soluble in a solvent for forming the photosensitive layer.

The method for producing the polyarylate resin (PA) is not particularly limited. The method for producing the polyarylate resin (PA) is, for example: a method for polycondensation of bisphenol (constituting repeating units derived from bisphenol) and dicarboxylic acid (constituting repeating units derived from dicarboxylic acid). The polycondensation may employ a well-known synthesis method (for example, solution polymerization, melt polymerization, or interfacial polymerization).

Examples of the bisphenol (used to constitute the repeating unit derived from bisphenol) include: a compound represented by the general formula (BP-1). Examples of dicarboxylic acids (used to form the repeating units derived from dicarboxylic acids) include: a compound represented by the general formula (DC-2). A in the formula (BP-1) has the same meaning as a in the formula (1). X in the general formula (DC-2) has the same meaning as X in the general formula (2).

In the polycondensation of bisphenol and dicarboxylic acid, one or both of a base and a catalyst may be added. An example of a base is sodium hydroxide. Examples of catalysts are: benzyl tributyl ammonium chloride, ammonium bromide, quaternary ammonium salts, triethylamine and trimethylamine.

In the photosensitive layer, the binder resin may be only polyarylate resin (PA). Alternatively, the photosensitive layer may further contain a binder resin (hereinafter, referred to as another binder resin) other than the polyarylate resin (PA) in addition to the polyarylate resin (PA). Other binding resins are, for example: thermoplastic resins (more specifically, polycarbonate resins, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, styrene-acrylic acid copolymers, polyethylene resins, ethylene-vinyl acetate copolymers, chlorinated polyethylene resins, polyvinyl chloride resins, polypropylene resins, ionomers, vinyl chloride-vinyl acetate copolymers, polyester resins, alkyd resins, polyamide resins, polyurethane resins, polysulfone resins, diallyl phthalate resins, ketone resins, polyvinyl butyral resins, and polyether resins), thermosetting resins (more specifically, silicone resins, epoxy resins, phenol resins, urea resins, melamine resins, and other crosslinking thermosetting resins), and light-curing resins (more specifically, epoxy-acrylic resins and polyurethane-acrylic copolymers).

(n-type pigment)

n-type pigments are pigments whose main charge carrier is an electron. In addition, p-type pigments are pigments in which the main charge carrier is a hole. By incorporating an n-type pigment into the photosensitive layer, the dispersibility of the charge generating agent in the photosensitive layer is improved, and a uniform photosensitive layer can be formed. Therefore, the charging stability of the photoreceptor can be improved. By containing the n-type pigment and the polyarylate resin (PA) in the photosensitive layer, the charging stability of the photoreceptor is significantly improved. Examples of n-type pigments are: azo pigments and perylene pigments.

Hereinafter, an azo pigment as an example of the n-type pigment will be described. Azo pigments have azo groups (-N ═ N-). Azo pigments are, for example: monoazo pigments and polyazo pigments (e.g., disazo pigments, trisazo pigments, and tetrazo pigments). Azo pigments may also be tautomers. The azo pigment may have a chlorine atom (chlorine group) in addition to the azo group.

Azo pigments are, for example: azo pigments are well known. Preferred examples of azo pigments are: pigment yellow (14, 17, 49, 65, 73, 83, 93, 94, 95, 128, 166 and 77), pigment orange (1, 2, 13, 34 and 36) and pigment red (30, 32, 61 and 144).

Further preferable examples of the azo pigment include: an azo pigment (pigment yellow 128) represented by chemical formula (a1), an azo pigment (pigment yellow 93) represented by chemical formula (a2), an azo pigment (pigment orange 13) represented by chemical formula (A3), and an azo pigment (pigment yellow 83) represented by chemical formula (a 4). Hereinafter, azo pigments represented by chemical formulae (a1), (a2), (A3), and (a4) may be described as azo pigments (a1), (a2), (A3), and (a4), respectively.

Next, a perylene pigment as an example of the n-type pigment will be explained. The perylene pigment has a perylene skeleton represented by the general formula (P-I). In the general formula (P-I), Q⁴⁰And Q⁴¹Each independently represents a divalent organic group.

A first specific example of the perylene pigment is a perylene pigment represented by the general formula (P-II).

In the general formula (P-II), Q⁴²And Q⁴³Each independently represents a hydrogen atom or a monovalent organic group. Z¹And Z²Each independently represents an oxygen atom or a nitrogen atom.

In the general formula (P-II), Q⁴²And Q⁴³When a monovalent organic group is represented, for example, an aliphatic hydrocarbon group, an alkoxy group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group are exemplified.

In the general formula (P-II), Q⁴²And Q⁴³When the aliphatic hydrocarbon group is represented, it may have any structure of a straight chain, a branched chain, a cyclic structure or a combination thereof. The aliphatic hydrocarbon group is saturated or unsaturated, and preferably saturated. In the general formula (P-II), Q⁴²And Q⁴³When the alkyl group represents an aliphatic hydrocarbon group, the alkyl group is preferably a C1-C20 aliphatic hydrocarbon group, more preferably a C1-C10 aliphatic hydrocarbon group. The C1-C10 aliphatic hydrocarbon group is preferably a C1-C10 alkyl group, more preferably a C1-C6 alkyl group, still more preferably a C1-C3 alkyl group, and particularly preferably a methyl group or an ethyl group.

In the general formula (P-II), Q⁴²And Q⁴³When it represents an alkoxy group, it is preferably a C1-C6 alkoxy group, more preferably a C1-C3 alkoxy group, and still more preferably a methoxy group or an ethoxy group.

In the general formula (P-II), Q⁴²And Q⁴³When the aralkyl group is represented, it is preferably a C7-C12 aralkyl group, more preferably a benzyl group, a phenethyl group, an α -naphthylmethyl group or a β -naphthylmethyl group, and still more preferably a benzyl group or a phenethyl group.

In the general formula (P-II), Q⁴²And Q⁴³When the aryl group is represented, it is preferably a C6-C14 aryl group, more preferably a C6-C10 aryl group, and still more preferably a phenyl group.

In the general formula (P-II), Q⁴²And Q⁴³When it represents a heterocyclic group, it is preferably a C3-C14 heterocyclic group, more preferably a C3-C14 heterocyclic group in which a heteroatom contains a nitrogen atom, and still more preferably a pyridyl group.

In the general formula (P-II), Q⁴²And Q⁴³When the aralkyl group, the aryl group and the heterocyclic group are represented, they may be substituted by a substituent. Such a substituent is preferably a C1-C6 alkyl group, a C1-C6 alkoxy group, a phenyl group, a halogen atom, a hydroxyl group, a cyano group, a nitro group or a phenylazo group, and more preferably a C1-C6 alkyl group (e.g., a methyl group), a halogen atom (e.g., a chlorine atom) or a phenylazo group.

In the general formula (P-II), Q⁴²And Q⁴³Preferably, the formula: C1-C6 alkyl group, C3-C14 heterocyclic group, C7-C12 aralkyl group, C1-C6 alkoxy group, C1-C6 alkyl group, halogen atom, unsubstituted C6-C14 aryl group, C6-C14 aryl group substituted with phenylazo group, or hydrogen atom. In the general formula (P-II), Q⁴²And Q⁴³More preferably, it is represented by: methyl group, ethyl group, pyridyl group, benzyl group, phenethyl group, ethoxy group, methoxy group, phenyl group, dimethylphenyl group (more preferably 3, 5-dimethylphenyl group), chlorophenyl group (more preferably 4-chlorophenyl group), phenylazophenyl group (more preferably 4-phenylazophenyl group), or a hydrogen atom. Q⁴²And Q⁴³Preferably identical to each other.

In the general formula (P-II), Q⁴²And Q⁴³Preferably, the formula: C1-C6 alkyl, unsubstituted C6-C14 aryl or C6-C14 aryl with C1-C6 alkyl substituents. In the general formula (P-II), Q⁴²And Q⁴³More preferably, it is represented by: methyl, phenyl, dimethylphenyl (more preferably 3, 5-dimethylphenyl). Q⁴²And Q⁴³Preferably identical to each other. Q⁴²And Q⁴³Preferably identical to each other.

A second specific example of the perylene pigment may be a compound represented by the general formula (P-III).

In the general formula (P-III), Q⁴⁴～Q⁴⁷Each independently represents a hydrogen atom or a monovalent organic group. Q⁴⁴And Q⁴⁵The ring may be bonded to each other. Q⁴⁶And Q⁴⁷The ring may be bonded to each other.

Q in the formula (P-III)⁴⁴～Q⁴⁷A monovalent organic group represented by the formula (I) and Q in the general formula (P-II)⁴²And Q⁴³The monovalent organic groups represented have the same meaning.

Q⁴⁴And Q⁴⁵Ring formed by bonding to each other and Q⁴⁶And Q⁴⁷The rings formed by bonding to each other are, for example: aromatic hydrocarbon rings, aromatic heterocyclic rings, alicyclic hydrocarbon rings, and alicyclic heterocyclic rings. Q⁴⁴And Q⁴⁵Ring formed by bonding to each other and Q⁴⁶And Q⁴⁷The ring formed by bonding to each other is preferably a benzene ring, a naphthalene ring, a pyridine ring or a tetrahydronaphthalene ring, and more preferably a benzene ring or a naphthalene ring. Q⁴⁴And Q⁴⁵The benzene ring and the naphthalene ring bonded with each other are respectively the same as Q⁴⁴And Q⁴⁵The imidazole ring formed by bonding is condensed. Q⁴⁶And Q⁴⁷The benzene ring and the naphthalene ring bonded with each other are respectively the same as Q⁴⁶And Q⁴⁷The imidazole ring formed by bonding is condensed.

Q⁴⁴And Q⁴⁵Ring formed by bonding to each other and Q⁴⁶And Q⁴⁷The rings bonded to each other may be substituted with a substituent. Such a substituent is preferably a halogen atom, and more preferably a chlorine atom or a fluorine atom.

In the general formula (P-III), Q⁴⁴And Q⁴⁵Preferably, they are bonded to each other to form an unsubstituted C6-C10 aromatic hydrocarbon ring or a C6-C10 aromatic hydrocarbon ring substituted with a halogen atom. Q⁴⁶And Q⁴⁷Preferably, they are bonded to each other to form an unsubstituted C6-C10 aromatic hydrocarbon ring or a C6-C10 aromatic hydrocarbon ring substituted with a halogen atom.

In the general formula (P-III), Q⁴⁴And Q⁴⁵Preferably, they are bonded to each other to form a benzene ring, a chlorobenzene ring, a fluorobenzene ring or a naphthalene ring. Q⁴⁶And Q⁴⁷Preferably, they are bonded to each other to form a benzene ring, a chlorobenzene ring, a fluorobenzene ring or a naphthalene ring.

Further preferred examples of perylene pigments are: perylene pigments represented by the following chemical formulae (P1) to (P17) (hereinafter, sometimes referred to as perylene pigments (P1) to (P17), respectively). The substitution positions of the pyridyl group in the chemical formula (P5) and the fluoro group in the chemical formula (P12) are not particularly limited.

Perylene pigments (P1) to (P3), (P5), (P6), (P9), (P10), (P11), and (P14) to (P17) are preferable examples of perylene pigments represented by the general formula (P-II). Perylene pigments (P4), (P7), (P8) and (P12) are preferable examples of the perylene pigments represented by the general formula (P-III). The perylene pigment (P13) is a preferable example of the perylene pigments other than the perylene pigments represented by the general formulae (P-II) and (P-III).

In order to improve the abrasion resistance and charging stability of the photoreceptor, the perylene pigment is preferably a perylene pigment (P1), (P2), or (P3).

The n-type pigment may be an n-type pigment other than perylene pigments and azo pigments (hereinafter, may be referred to as another n-type pigment). Other n-type pigments are, for example: polycyclic quinone pigments, squarylium pigments, pyranthrone pigments, perinone pigments, isoindoline pigments, quinacridone pigments, pyrazolone pigments and benzimidazolone pigments.

The photosensitive layer may contain only 1 type of n-type pigment, or may contain 2 or more types of n-type pigments. In order to improve the abrasion resistance and charging stability of the photoreceptor, the content of the n-type pigment is preferably more than 0.00 part by mass, more preferably 0.01 part by mass or more, and further preferably 0.50 part by mass or more, relative to 1.00 part by mass of the charge generating agent. In order to improve the abrasion resistance and charging stability of the photoreceptor, the content of the n-type pigment is preferably 3.00 parts by mass or less, more preferably 2.70 parts by mass or less, further preferably 2.00 parts by mass or less, and particularly preferably 1.00 parts by mass or less, relative to 1.00 parts by mass of the charge generating agent. When the photosensitive layer contains 2 or more types of n-type pigments, the content thereof means the total content of 2 or more types of n-type pigments.

(additives)

Examples of additives are: singlet quenchers, softeners, surface modifiers, extenders, thickeners, dispersion stabilizers, waxes, donors, surfactants, plasticizers, sensitizers, electron acceptor compounds and leveling agents.

(Charge generating agent)

Examples of charge generators are: phthalocyanine pigments, perylene pigments, disazo pigments, trisazo pigments, dithione-pyrrolopyrrole (dithioketo-pyrrozole) pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaric acid pigments, indigo pigments, azulene pigments, cyanine pigments, powders of inorganic photoconductive materials (e.g., selenium-tellurium, selenium-arsenic, cadmium sulfide, and amorphous silicon), pyran pigments, anthanthrone pigments, triphenylmethane pigments, threne pigments, toluidine pigments, pyrazoline pigments, and quinacridone pigments. The photosensitive layer may contain only 1 kind of charge generating agent, or may contain 2 or more kinds.

Examples of phthalocyanine pigments are: metal-free phthalocyanines and metal phthalocyanines. The metal phthalocyanines are, for example: oxytitanium phthalocyanine, hydroxygallium phthalocyanine and chlorogallium phthalocyanine. The metal-free phthalocyanine is represented by the chemical formula (CGM-1). The oxytitanium phthalocyanine is represented by the chemical formula (CGM-2).

The phthalocyanine pigment may be crystalline or amorphous. The metal phthalocyanine-free crystals are, for example: an X-type crystal of metal-free phthalocyanine (hereinafter, sometimes referred to as X-type metal-free phthalocyanine). Crystals of oxytitanium phthalocyanine are, for example: crystal of oxytitanium phthalocyanine of α type, β type and Y type (hereinafter, sometimes referred to as "α type", "β type" and "Y type", respectively).

For example, in a digital optical image forming apparatus (for example, a laser printer or a facsimile machine using a light source such as a semiconductor laser), it is preferable to use a photoreceptor having sensitivity in a wavelength region of 700nm or more. The charge generating agent is preferably a phthalocyanine-based pigment, more preferably a metal-free phthalocyanine or oxytitanium phthalocyanine, still more preferably an X-type metal-free phthalocyanine or Y-type oxytitanium phthalocyanine, and particularly preferably a Y-type oxytitanium phthalocyanine, from the viewpoint of having a high quantum yield in a wavelength region of 700nm or more. Such a charge generating agent not only has a high quantum yield in a wavelength region of 700nm or more, but also can be well dispersed in a photosensitive layer by interaction with an n-type pigment.

The Y-type oxytitanium phthalocyanine has a main peak at 27.2 ° of the bragg angle (2 θ ± 0.2 °) in the CuK α characteristic X-ray diffraction spectrum, for example. The main peak in the CuK α characteristic X-ray diffraction spectrum means a peak having a first or second large intensity in a range where the bragg angle (2 θ ± 0.2 °) is 3 ° or more and 40 ° or less. In the CuK α characteristic X-ray diffraction spectrum, the Y-type oxytitanium phthalocyanine has no peak at 26.2 ℃.

The CuK α characteristic X-ray diffraction spectrum can be measured, for example, by the following method. First, a sample (oxytitanium phthalocyanine) was filled in a sample holder of an X-ray diffraction apparatus ("RINT (Japanese registered trademark) 1100" manufactured by Rigaku Corporation) at X-ray tube Cu, tube voltage 40kV, tube current 30mA and CuK α characteristic X-ray wavelength

The X-ray diffraction spectrum was measured. The measurement range (2 θ) is, for example, 3 ° to 40 ° (start angle 3 ° and stop angle 40 °), and the scanning speed is, for example, 10 °/min. And determining a main peak according to the obtained X-ray diffraction spectrum, and reading the Bragg angle of the main peak.

The content of the charge generating agent is preferably 0.1 part by mass or more and 50 parts by mass or less, and more preferably 0.5 part by mass or more and 5 parts by mass or less, with respect to 100 parts by mass of the binder resin.

(Electron transport agent)

Examples of electron transport agents are: quinone compounds, imide compounds, hydrazone compounds, malononitrile compounds, thiopyran compounds, trinitrothioxanthone compounds, 3,4,5, 7-tetranitro-9-fluorenone compounds, dinitroanthracene compounds, dinitroacridine compounds, tetracyanoethylene, 2,4, 8-trinitrothioxanthone, dinitrobenzene, dinitroacridine, succinic anhydride, maleic anhydride and dibromomaleic anhydride. Quinone compounds are for example: diphenoquinone compounds, azoquinone compounds, anthraquinone compounds, naphthoquinone compounds, nitroanthraquinone compounds and dinitroanthraquinone compounds. The photosensitive layer may contain only 1 kind of electron-transporting agent, or may contain 2 or more kinds of electron-transporting agents.

Preferred examples of the electron-transporting agent include compounds represented by the following general formulae (10), (11), (12), (13) and (14) (hereinafter, sometimes referred to as the electron-transporting agents (10), (11), (12), (13) and (14), respectively) in order to improve the abrasion resistance and charging stability of the photoreceptor.

In the general formula (10), Q¹、Q²、Q³And Q⁴Each independently represents a hydrogen atom, a C1-C6 alkyl group, a C1-C6 alkoxy group, a C6-C14 aryl group or a C7-C20 aralkyl group.

In the general formula (10), Q¹、Q²、Q³And Q⁴Each independently preferably represents a hydrogen atom or a C1-C6 alkyl group. More preferably: q¹And Q⁴Each independently represents a C1-C6 alkyl group, Q²And Q³Represents a hydrogen atom. Q¹、Q²、Q³And Q⁴When it represents a C1-C6 alkyl group, it is preferably a C1-C5 alkyl group, and more preferably a1, 1-dimethylpropyl group.

In the general formula (11), Q⁵Represents a C1-C6 alkyl group or a C6-C14 aryl group. Q⁶Represents a C1-C6 alkyl group, a C6-C14 aryl group, a C1-C6 alkoxy group, a C7-C20 aralkyl group, a C6-C14 aryloxy group or a C7-C20 aralkyloxy group. Q⁷Represents a C1-C6 alkyl group. v represents an integer of 0 to 4.

In the general formula (11), Q⁵Preferably represents a C6-C14 aryl group, more preferably represents a phenyl group. Q⁶Preferably represents a C7-C20 aralkyloxy group, more preferably represents a C7-C10 aralkyloxy group, and still more preferably represents a benzyloxy group. v preferably represents 0.

In the general formula (12), Q⁸And Q⁹Independently of one another, represents a C6-C14 aryl group having at least one C1-C6 alkyl substituent or an unsubstituted C6-C14 aryl group.

In the general formula (12), Q⁸And Q⁹Each independently preferably represents a C6-C14 aryl group having 2 or more and 5 or less (e.g., 2) C1-C6 alkyl substituents, more preferably represents a phenyl group having 2 or more and 5 or less (e.g., 2) C1-C3 alkyl substituents, still more preferably represents an ethylmethylphenyl group, and particularly preferably represents a 2-ethyl-6-methylphenyl group.

In the general formula (13), Q¹⁰、Q¹¹、Q¹²And Q¹³Each independently represents a hydrogen atom, a C1-C6 alkyl group, a C2-C6 alkenyl group, a C1-C6 alkoxy group, a C6-C14 aryl group, a C7-C20 aralkyl group or a C3-C14 heterocyclic group.

In the general formula (13), Q¹⁰、Q¹¹、Q¹²And Q¹³Each independently preferably represents a C1-C6 alkyl group, more preferably represents a C1-C4 alkyl group, and still more preferably represents a methyl group or a tert-butyl group.

In the general formula (14), Q¹⁴、Q¹⁵And Q¹⁶Independently of one another, a C1-C6 alkyl group, a C6-C14 aryl group substituted with a halogen atom, or an unsubstituted C6-C14 aryl group.

In the general formula (14), Q¹⁴And Q¹⁵Each independently preferably represents a C1-C6 alkyl group, more preferably a C1-C4 alkyl group, and still more preferably a tert-butyl group. Q¹⁶Preferably represents a C6-C14 aryl group substituted with a halogen atom, more preferably represents a phenyl group substituted with a halogen atom, still more preferably represents a chlorophenyl group, and particularly preferably represents a 4-chlorophenyl group.

Further preferable examples of the electron transport agent include compounds represented by chemical formulas (ET1), (ET2), (ET3), (ET4), and (ET5) (hereinafter, sometimes referred to as electron transport agents (ET1), (ET2), (ET3), (ET4), and (ET5), respectively) in order to improve abrasion resistance and charge stability of the photoreceptor.

The electron transport agent (ET1) is a preferred example of the electron transport agent (10). The electron transport agent (ET2) is a preferred example of the electron transport agent (11). The electron transport agent (ET3) is a preferred example of the electron transport agent (12). The electron transport agent (ET4) is a preferred example of the electron transport agent (13). The electron transport agent (ET5) is a preferred example of the electron transport agent (14).

The content of the electron-transporting agent is preferably 5 parts by mass or more and 150 parts by mass or less, and more preferably 10 parts by mass or more and 50 parts by mass or less, with respect to 100 parts by mass of the binder resin.

(hole transport agent)

Hole transporters are for example: oxadiazole compounds (e.g., 2, 5-bis (4-methylaminophenyl) -1,3, 4-oxadiazole), styrene compounds (e.g., 9- (4-diethylaminostyryl) anthracene), carbazole compounds (e.g., polyvinylcarbazole), organopolysilane compounds, pyrazoline compounds (e.g., 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline), hydrazone compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, and triazole compounds. The photosensitive layer may contain only 1 kind of hole-transporting agent, or may contain 2 or more kinds of hole-transporting agents.

Preferred examples of the hole-transporting agent for improving the abrasion resistance and the charging stability of the photoreceptor include compounds represented by the following general formulae (20), (21), (22), (23), (24), (25), (26) and (27) (hereinafter, sometimes referred to as the hole-transporting agents (20), (21), (22), (23), (24), (25), (26) and (27), respectively).

In the general formula (20), R¹¹、R¹²、R¹³、R¹⁴、R¹⁵And R¹⁶Each independently represents a C1-C8 alkyl group or a phenyl group. R¹⁷And R¹⁸Each independently represents hydrogenAtom, C1-C8 alkyl or phenyl. b1, b2, b3 and b4 are independent of each other and each represents an integer of 0 to 5 inclusive. b5 and b6 are each independently an integer of 0 to 4. d and e are each independently 0 or 1.

In the general formula (20), when b1 represents an integer of 2 to 5, a plurality of R¹¹The same or different from each other. b2 represents an integer of 2 to 5 inclusive, a plurality of R¹²The same or different from each other. b3 represents an integer of 2 to 5 inclusive, a plurality of R¹³The same or different from each other. b4 represents an integer of 2 to 5 inclusive, a plurality of R¹⁴The same or different from each other. b5 represents an integer of 2 to 4 inclusive, a plurality of R¹⁵The same or different from each other. b6 represents an integer of 2 to 4 inclusive, a plurality of R¹⁶The same or different from each other.

In the general formula (20), R¹¹、R¹²、R¹³、R¹⁴、R¹⁵And R¹⁶Each independently preferably represents a C1-C8 alkyl group, more preferably a C1-C3 alkyl group, and still more preferably a methyl group or an ethyl group. R¹⁷And R¹⁸Preferably represents a hydrogen atom. b1, b2, b3 and b4 are each independently an integer of 0 to 2. b5 and b6 preferably represent 0. As described above, d and e are each independently 0 or 1.

In the general formula (21), R²⁰Represents a hydrogen atom, a C1-C8 alkyl group, a C1-C8 alkoxy group, a phenyl group having a C1-C8 alkyl substituent, or an unsubstituted phenyl group. R²¹、R²²And R²³Independently of one another, represents a C1-C8 alkyl group or a C1-C8 alkoxy group. f1, f2 and f3 are each independently an integer of 0 to 5. f4 represents 0 or 1.

In the general formula (21), when f1 represents an integer of 2 to 5, a plurality of R²¹The same or different from each other. f2 represents an integer of 2 to 5 inclusive, a plurality of R²²The same or different from each other. f3 represents an integer of 2 to 5 inclusive, a plurality of R²³The same or different from each other.

In the general formula (21), R²⁰Preferably represents a phenyl group having a C1-C8 alkyl substituent or an unsubstituted phenyl group, and more preferably representsUnsubstituted phenyl. R²¹、R²²And R²³Each independently preferably represents a C1-C8 alkyl group, more preferably a C1-C3 alkyl group, and still more preferably a methyl group. f1, f2 and f3 are each independently, preferably 0 or 1. As described above, f4 represents 0 or 1.

In the general formula (22), R³¹、R³²、R³³、R³⁴And R³⁵Independently of one another, represents a C1-C8 alkyl group or a C1-C8 alkoxy group. g1, g2, g3, g4 and g5 are each independently an integer of 0 to 5.

In the general formula (22), when g1 represents an integer of 2 to 5, a plurality of R³¹The same or different from each other. g2 represents an integer of 2 to 5 inclusive, a plurality of R³²The same or different from each other. g3 represents an integer of 2 to 5 inclusive, a plurality of R³³The same or different from each other. g4 represents an integer of 2 to 5 inclusive, a plurality of R³⁴The same or different from each other. g5 represents an integer of 2 to 5 inclusive, a plurality of R³⁵The same or different from each other.

In the general formula (22), R³¹、R³²、R³³、R³⁴And R³⁵Each independently preferably represents a C1-C8 alkyl group, more preferably a C1-C3 alkyl group, and still more preferably a methyl group. g1, g2, g3, g4 and g5 preferably represent 1.

In the general formula (23), R⁴¹、R⁴²、R⁴³、R⁴⁴、R⁴⁵And R⁴⁶Independently of one another, represents C1-C8 alkyl, phenyl or C1-C8 alkoxy. h1, h2, h4 and h5 are independent of each other and each represents an integer of 0 to 5. h3 and h6 are independent of each other and each represents an integer of 0 to 4.

In the general formula (23), when h1 represents an integer of 2 to 5, a plurality of R⁴¹The same or different from each other. h2 represents an integer of 2 to 5 inclusive, and R's are several⁴²The same or different from each other. h4 represents an integer of 2 to 5 inclusive, and R's are several⁴⁴The same or different from each other. h5 represents an integer of 2 to 5 inclusive, and R's are several⁴⁵The same or different from each other. h3 represents an integer of 2 to 4, a plurality of R⁴³The same or different from each other. h6 represents an integer of 2 to 4, a plurality of R⁴⁶The same or different from each other.

In the general formula (23), R⁴¹、R⁴²、R⁴³、R⁴⁴、R⁴⁵And R⁴⁶Each independently preferably represents a C1-C8 alkyl group, more preferably a C1-C3 alkyl group, and still more preferably a methyl group or an ethyl group. h1, h2, h4 and h5 are each independently an integer of 0 to 2. h3 and h6 preferably represent 0.

In the general formula (24), R⁶¹、R⁶²And R⁶³Each independently represents a C1-C8 alkyl group. R⁶⁴、R⁶⁵And R⁶⁶Each independently represents a hydrogen atom or a C1-C8 alkyl group.

In the general formula (24), R⁶¹、R⁶²And R⁶³Each independently preferably represents a C1-C8 alkyl group, more preferably a C1-C3 alkyl group, and still more preferably a methyl group. R⁶⁴、R⁶⁵And R⁶⁶Preferably represents a hydrogen atom.

In the general formula (25), R⁷¹、R⁷²、R⁷³And R⁷⁴Each independently represents a C1-C8 alkyl group. j1, j2, j3 and j4 are independent of each other and each represents an integer of 0 to 5. j5 represents 0 or 1.

In the general formula (25), when j1 represents an integer of 2 to 5, a plurality of R⁷¹The same or different from each other. j2 represents an integer of 2 to 5, and R' s⁷²The same or different from each other. j3 represents an integer of 2 to 5, and R' s⁷³The same or different from each other. j4 represents an integer of 2 to 5, and R' s⁷⁴The same or different from each other.

In the general formula (25), R⁷¹、R⁷²、R⁷³And R⁷⁴Each independently preferably represents a C1-C3 alkyl group, more preferably a methyl or ethyl group. j1, j2, j3 and j4 are each independently, preferably 0 or 1. As described above, j5 represents 0 or 1.

In the general formula (26), R⁸¹、R⁸²And R⁸³Each independently represents C1-C8 alkyl, phenyl or C1-C8 alkoxy. R⁸⁴And R⁸⁵Each independently represents a phenyl group having a C1-C8 alkyl substituent, an unsubstituted phenyl group, a hydrogen atom, a C1-C8 alkyl group or a C1-C8 alkoxy group. k1, k2, and k3 are each independently an integer of 0 to 5. k4 and k5 are independent of each other and represent 1 or 2.

In the general formula (26), when k1 represents an integer of 2 to 5, a plurality of R⁸¹The same or different from each other. When k2 represents an integer of 2 to 5, a plurality of R⁸²The same or different from each other. When k3 represents an integer of 2 to 5, a plurality of R⁸³The same or different from each other.

In the general formula (26), R⁸¹、R⁸²And R⁸³Each independently preferably represents a C1-C8 alkyl group, more preferably a C1-C6 alkyl group, and still more preferably a methyl group, an ethyl group or an n-butyl group. R⁸⁴And R⁸⁵Preferably represents a hydrogen atom. k1, k2 and k3 are each independently preferably an integer of 0 to 2. As described above, k4 and k5 are independent of each other and represent 1 or 2.

In the general formula (27), R⁹¹、R⁹²And R⁹³Each independently represents a C1-C8 alkyl group. R⁹⁴Represents a C1-C8 alkyl group or a hydrogen atom. v1, v2 and v3 are independent of each other and each represents an integer of 0 to 5 inclusive.

In the general formula (27), when v1 represents an integer of 2 to 5, a plurality of R' s⁹¹The same or different from each other. When v2 represents an integer of 2 to 5, a plurality of R⁹²The same or different from each other. When v3 represents an integer of 2 to 5, a plurality of R⁹³The same or different from each other.

In the general formula (27), R⁹⁴Preferably represents a hydrogen atom. v1, v2 and v3 preferably represent 0.

Further preferable examples of the hole-transporting agent for improving the abrasion resistance and charge stability of the photoreceptor include compounds represented by chemical formulae (HT1), (HT2), (HT3), (HT4), (HT5), (HT6), (HT7), (HT8), (HT9), (HT10), (HT11), (HT12), (HT13), and (HT14) (hereinafter, sometimes referred to as hole-transporting agents (HT1), (HT2), (HT3), (HT4), (HT5), (HT6), (HT7), (HT8), (HT9), (HT10), (HT11), (HT12), (HT13), and (HT 14)).

Further, both the hole-transporting agents (HT1) and (HT2) are preferable examples of the hole-transporting agent (20). Both the hole-transporting agents (HT3) and (HT4) are preferred examples of the hole-transporting agent (21). The hole-transporting agent (HT5) is a preferred example of the hole-transporting agent (22). Both the hole-transporting agents (HT6) and (HT7) are preferred examples of the hole-transporting agent (23). The hole-transporting agent (HT8) is a preferred example of the hole-transporting agent (24). The hole-transporting agents (HT9), (HT10) and (HT11) are preferred examples of the hole-transporting agent (25). Both hole-transporting agents (HT12) and (HT13) are preferred examples of hole-transporting agents (26). The hole-transporting agent (HT14) is a preferred example of the hole-transporting agent (27).

The content of the hole transporting agent is preferably 10 parts by mass or more, more preferably 50 parts by mass or more, and further preferably 65 parts by mass or more, with respect to 100 parts by mass of the binder resin. The content of the hole transporting agent is preferably 300 parts by mass or less, more preferably 100 parts by mass or less, and further preferably 75 parts by mass or less, with respect to 100 parts by mass of the binder resin.

(combination of materials)

In order to improve the abrasion resistance and charging stability of the photoreceptor, the combination of the n-type pigment and the binder resin is preferably each of combination nos. D1 to D33 in table 1. For the same reason, it is preferable that: the combination of the n-type pigment and the binder resin was each of combination Nos. D1 to D33 in Table 1, and the charge generating agent was Y-type oxytitanium phthalocyanine.

[ TABLE 1 ]

In order to improve the abrasion resistance and charging stability of the photoreceptor, the combination of the hole transporting agent, the n-type pigment and the binder resin is preferably each of combination nos. E1 to E59 in table 2. For the same reason, it is preferable that: the combination of the hole transporting agent, the n-type pigment and the binder resin is each of combination nos. E1 to E59 in table 2, and the charge generating agent is Y-type oxytitanium phthalocyanine.

[ TABLE 2 ]

In order to improve the abrasion resistance and charging stability of the photoreceptor, the combination of the hole transporting agent, the electron transporting agent, the n-type pigment and the binder resin is preferably each of combination nos. F1 to F67 in tables 3 and 4. For the same reason, it is preferable that: the combination of the hole transporting agent, the electron transporting agent, the n-type pigment and the binder resin is each of combination nos. F1 to F67 in table 3, and the charge generating agent is Y-type oxytitanium phthalocyanine.

[ TABLE 3 ]

No.

n type

HTM

ETM

Resin composition

No.

n type

HTM

ETM

Resin composition

F1

A1

HT1

ET1

I

F25

A1

HT1

ET1

R1

F2

A2

HT1

ET1

I

F26

A2

HT1

ET1

R1

F3

A3

HT1

ET1

I

F27

A3

HT1

ET1

R1

F4

A4

HT1

ET1

I

F28

A4

HT1

ET1

R1

F5

P1

HT1

ET1

I

F29

P1

HT1

ET1

R1

F6

P2

HT1

ET1

I

F30

P2

HT1

ET1

R1

F7

P3

HT1

ET1

I

F31

P3

HT1

ET1

R1

F8

A1

HT2

ET1

I

F32

A1

HT2

ET1

R1

F9

A1

HT3

ET1

I

F33

A1

HT3

ET1

R1

F10

A1

HT4

ET1

I

F34

A1

HT4

ET1

R1

F11

A1

HT5

ET1

I

F35

A1

HT5

ET1

R1

F12

A1

HT6

ET1

I

F36

A1

HT6

ET1

R1

F13

A1

HT7

ET1

I

F37

A1

HT7

ET1

R1

F14

A1

HT8

ET1

I

F38

A1

HT8

ET1

R1

F15

A1

HT9

ET1

I

F39

A1

HT9

ET1

R1

F16

A1

HT10

ET1

I

F40

A1

HT10

ET1

R1

F17

A1

HT11

ET1

I

F41

A1

HT11

ET1

R1

F18

A1

HT12

ET1

I

F42

A1

HT12

ET1

R1

F19

A1

HT13

ET1

I

F43

A1

HT13

ET1

R1

F20

A1

HT14

ET1

I

F44

A1

HT14

ET1

R1

F21

A1

HT1

ET2

I

F45

A1

HT1

ET2

R1

F22

A1

HT1

ET3

I

F46

A1

HT1

ET3

R1

F23

A1

HT1

ET4

I

F47

A1

HT1

ET4

R1

F24

A1

HT1

ET5

I

F48

A1

HT1

ET5

R1

[ TABLE 4 ]

In tables 1 to 4, "No." represents "combination No.", "n-type" represents "n-type pigment", "HTM" represents "hole transporting agent", "ETM" represents "electron transporting agent", and "resin" represents polyarylate resin as a binder resin.

(conductive substrate)

The conductive substrate is not particularly limited as long as it can be used as a conductive substrate of a photoreceptor. The conductive substrate may be formed of a conductive material at least on the surface portion thereof. An example of a conductive substrate is: a conductive substrate made of a conductive material. Another example of a conductive substrate is: a conductive substrate coated with a conductive material. The conductive material is, for example: 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 2 or more kinds (for example, as an alloy) may be used in combination. Among these conductive materials, aluminum or an aluminum alloy is preferable from the viewpoint of good charge transfer from the photosensitive layer to the conductive substrate.

The shape of the conductive substrate is appropriately selected according to the structure of the image forming apparatus. The shape of the conductive substrate is, for example: sheet and drum. 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 (resin for intermediate layer) used in the intermediate layer. It can be considered that: the presence of the intermediate layer allows smooth current flow to be generated when the photoreceptor is exposed, while maintaining an insulating state to such an extent that leakage current can be suppressed, thereby suppressing an increase in resistance.

The inorganic particles are, for example: particles of metals (e.g., aluminum, iron, and copper), particles of metal oxides (e.g., titanium dioxide, aluminum oxide, zirconium oxide, tin oxide, and zinc oxide), and particles of non-metal oxides (e.g., silicon dioxide). These inorganic particles may be used alone or in combination of 2 or more.

Examples of the resin for the intermediate layer are the same as those of the binder resin described above. In order to form the intermediate layer and the photosensitive layer well, the resin for the intermediate layer is preferably different from the binder resin contained in the photosensitive layer. The intermediate layer may also contain additives. Examples of the additive contained in the intermediate layer are the same as those of the additive contained in the photosensitive layer.

(method for manufacturing photoreceptor)

Next, an example of a method for manufacturing the photoreceptor will be described. The method for manufacturing the photoreceptor includes a photosensitive layer forming step. In the photosensitive layer forming step, a coating liquid for forming a photosensitive layer (hereinafter, sometimes referred to as a coating liquid for a photosensitive layer) is prepared. The photosensitive layer is coated on the conductive substrate with the coating liquid. Then, at least a part of the solvent contained in the coating liquid for the photosensitive layer to be coated is removed, thereby forming a photosensitive layer. The coating liquid for photosensitive layers contains, for example, a charge generator, a hole transporting agent, an electron transporting agent, a binder resin, an n-type pigment and a solvent. A coating liquid for photosensitive layer is prepared by dissolving or dispersing a charge generating agent, a hole transporting agent, an electron transporting agent, a binder resin, and an n-type pigment in a solvent.

The solvent contained in the coating liquid for photosensitive layer is not particularly limited as long as it can dissolve or disperse each component contained in the coating liquid for photosensitive layer. Examples of solvents are: alcohols (more specifically, methanol, ethanol, isopropanol, butanol, and the like), aliphatic hydrocarbons (more specifically, n-hexane, octane, cyclohexane, and the like), aromatic hydrocarbons (more specifically, benzene, toluene, xylene, and the like), halogenated hydrocarbons (more specifically, dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene, and the like), ethers (more specifically, dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and the like), ketones (more specifically, acetone, methyl ethyl ketone, cyclohexanone, and the like), esters (more specifically, ethyl acetate, methyl acetate, and the like), dimethyl formaldehyde, dimethyl formamide, and dimethyl sulfoxide. These solvents may be used alone or in combination of two or more.

The photosensitive layer coating liquid is prepared by mixing and dispersing the respective components in a solvent. In the mixing or dispersing operation, for example, a bead mill, a roll mill, a ball mill, an attritor, a paint shaker, or an ultrasonic disperser can be used.

The method for coating with the coating liquid for photosensitive layer is not particularly limited as long as it can uniformly coat the coating liquid for photosensitive layer. The coating method is, for example: dip coating, spray coating, spin coating, and bar coating.

Examples of a method for removing at least a part of the solvent contained in the coating liquid for photosensitive layer include: heating, reducing the pressure, or a combination of heating and reducing the pressure. More specifically, a method of performing heat treatment (hot air drying) using a high-temperature dryer or a reduced-pressure dryer is given. The temperature of the heat treatment is, for example, 40 ℃ to 150 ℃. The time for the heat treatment is, for example, 3 minutes to 120 minutes.

The method for manufacturing the photoreceptor may further include a step of forming an intermediate layer, if necessary. The intermediate layer can be formed by a known method.

< image forming apparatus >

Next, an image forming apparatus including the photoreceptor 1 of the present embodiment will be described. Hereinafter, a tandem color image forming apparatus will be described as an example with reference to fig. 4. Fig. 4 is a cross-sectional view of an example of an image forming apparatus.

The image forming apparatus 110 in fig. 4 includes an image forming unit 40a, an image forming unit 40b, an image forming unit 40c, an image forming unit 40d, a transfer belt 50, and a fixing device 52. Hereinafter, the

image forming units

40a, 40b, 40c, and 40d are all described as the image forming unit 40 unless otherwise noted.

The image forming unit 40 includes an image carrier 100, a charging device 42, an exposure device 44, a developing device 46, a transfer device 48, and a cleaning device 54. The image bearing member 100 is the photoreceptor 1 of the present embodiment.

As described above, the photoreceptor 1 of the present embodiment has excellent abrasion resistance and charging stability. Therefore, by providing the photoreceptor 1 as the image carrier 100, the image forming apparatus 110 has excellent durability and can form a good-quality image on the recording medium P.

An image carrier 100 is provided at a central position of the image forming unit 40. The image carrier 100 is provided to be rotatable in the arrow direction (counterclockwise direction). Around the image carrier 100, a charging device 42, an exposure device 44, a developing device 46, a transfer device 48, and a cleaning device 54 are provided in this order from the upstream side in the rotational direction of the image carrier 100.

Toner images of several colors (for example, four colors of black, cyan, magenta, and yellow) are sequentially superimposed on the recording medium P on the transfer belt 50 by each of the image forming units 40a to 40 d.

The charging device 42 charges the surface (for example, the circumferential surface) of the image carrier 100 to a positive polarity. The charging device 42 is, for example, a grid corotron charger.

The exposure device 44 irradiates the surface of the charged image carrier 100 with light. That is, the exposure device 44 exposes the surface of the charged image carrier 100. Thereby, an electrostatic latent image is formed on the surface of the image carrier 100. Based on the image data input into the image forming apparatus 110, an electrostatic latent image is formed.

The developing device 46 supplies toner to the surface of the image carrier 100 to develop the electrostatic latent image into a toner image. The developing device 46 comes into contact with the surface of the image carrier 100. That is, the image forming apparatus 110 employs a contact development system. The developing device 46 is, for example, a developing roller. In the case where the developer is a one-component developer, the developing device 46 supplies toner as the one-component developer to the electrostatic latent image formed on the image carrier 100. In the case where the developer is a two-component developer, the developing device 46 supplies toner contained in the two-component developer and toner in the carrier to the electrostatic latent image formed on the image bearing member 100. Thereby, the image bearing member 100 bears the toner image.

The time (hereinafter, sometimes referred to as exposure-development time) from when the predetermined region on the surface of the image carrier 100 passes the exposure position PA until when the predetermined region moves to the development position PB is 100 milliseconds or less. The exposure position PA is a position at which light emitted from the exposure device 44 is incident on the surface of the image carrier 100. The developing position PB is a position at which the surface of the image carrier 100 abuts against the developing device 46 or the surface of the image carrier 100 is closest to the developing device 46. The defined area is for example a point on the surface of the image carrier 100.

The transfer belt 50 conveys the recording medium P between the image carrier 100 and the transfer device 48. The transfer belt 50 is an endless belt. The transfer belt 50 is provided to be rotatable in an arrow direction (clockwise direction).

The transfer device 48 transfers the toner image developed by the developing device 46 from the surface of the image carrier 100 to a recording medium P as a transfer target. Specifically, when the transfer device 48 transfers the toner image from the surface of the image carrier 100 to the recording medium P, the surface of the image carrier 100 comes into contact with the recording medium P. That is, the image forming apparatus 110 employs a direct transfer system. The transfer device 48 is, for example, a transfer roller.

The cleaning device 54 is used to collect toner adhering to the surface of the image carrier 100. The washing device 54 includes a housing 541 and a cleaning roller 542. In addition, the cleaning device 54 does not have a cleaning blade. The cleaning roller 542 is disposed inside the housing 541. The cleaning roller 542 is disposed in contact with the surface of the image carrier 100. The cleaning roller 542 grinds the surface of the image carrier 100, and collects the toner adhering to the surface of the image carrier 100 into the housing 541.

After the toner image is transferred onto the recording medium P by the transfer device 48, the recording medium P is conveyed to the fixing device 52 by the transfer belt 50. The fixing device 52 is, for example, a heating roller and/or a pressure roller. The unfixed toner image transferred by the transfer device 48 is heated and/or pressurized by the fixing device 52. The toner image is heated and/or pressurized, whereby the toner image is fixed on the recording medium P. As a result, an image is formed on the recording medium P.

As described above, although an example of the image forming apparatus is described, the image forming apparatus is not limited to the image forming apparatus 110 described above. The image forming apparatus 110 described above is a color image forming apparatus, but the image forming apparatus may be a monochrome image forming apparatus. In such a case, the image forming apparatus may include only 1 image forming unit, for example. Although the image forming apparatus 110 described above employs a tandem system, the image forming apparatus may employ a Rotary system (Rotary system), for example. The charging device 42 is described by taking a grid corotron charger as an example, but the charging device may be a charging device other than a grid corotron charger (for example, a charging roller, a charging brush, or a corotron charger). The image forming apparatus 110 described above employs a contact development system, but the image forming apparatus may employ a non-contact development system. The image forming apparatus 110 described above employs a direct transfer system, but the image forming apparatus may employ an intermediate transfer system. When the image forming apparatus employs the intermediate transfer system, the intermediate transfer belt corresponds to a transfer target. The cleaning device 54 described above includes the cleaning roller 542 and does not include the cleaning blade, but may be a cleaning device including the cleaning roller 542 and the cleaning blade. The image forming unit 40 described above does not include an electrostatic charge eliminating device, but the image forming unit may include an electrostatic charge eliminating device.

< processing box >

Next, an example of a process cartridge including the photoreceptor 1 according to the present embodiment will be described with reference to fig. 4. The process cartridge corresponds to each of the image forming units 40a to 40 d. The process cartridge includes an image carrier 100. The image bearing member 100 is the photoreceptor 1 of the present embodiment. As described above, the photoreceptor 1 of the present embodiment has excellent abrasion resistance and charging stability. Therefore, by providing the photoreceptor 1 as the image carrier 100, the process cartridge has excellent durability and can form a good-quality image on the recording medium P.

The process cartridge may further include at least one of a charging device 42, an exposure device 44, a developing device 46, a transfer device 48, and a cleaning device 54 in addition to the image carrier 100. That is, the process cartridge may further include at least one device selected from the group consisting of the charging device 42, the exposure device 44, the developing device 46, the transfer device 48, and the cleaning device 54, in addition to the image carrier 100. The process cartridge may further include a static eliminator (not shown). The process cartridge is designed to be detachable with respect to the image forming apparatus 110. Therefore, the process cartridge is easy to handle, and when the sensitivity characteristics and the like of the image carrier 100 are deteriorated, the components included in the image carrier 100 can be easily and quickly replaced. As described above, the process cartridge including the photoreceptor 1 according to the present embodiment is described with reference to fig. 4.

[ examples ] A method for producing a compound

The present invention will be described in more detail with reference to examples. However, the present invention is not limited in any way to the scope of the examples.

< Material for Forming photosensitive layer >

First, as materials for forming a photosensitive layer of the photoreceptor, the following charge generating agent, electron transporting agent, hole transporting agent, binder resin, and n-type pigment are prepared.

(Charge generating agent)

The Y-type oxytitanium phthalocyanine described in the embodiment was prepared as a charge generating agent.

(Electron transport agent)

The electron-transporting agents (ET1) to (ET5) described in the embodiments were prepared as electron-transporting agents.

(hole transport agent)

Hole-transporting agents (HT1) to (HT14) described in the embodiments were prepared as hole-transporting agents.

(Binder resin)

Polyarylate resins (R1) to (R12) described in the embodiment were prepared as binder resins. The viscosity average molecular weights of the polyarylate resins (R1) to (R12) were all 60000.

As the binder resin used in the comparative example, polycarbonate resins having repeating units represented by chemical formulae (R13), (R14), and (R15) (hereinafter, each of which is described as a polycarbonate resin (R13), (R14), and (R15)) were prepared. The viscosity average molecular weights of the polycarbonate resins (R13), (R14) and (R15) were all 60000. The polycarbonate resin (R13) corresponds to the bisphenol Z-type polycarbonate resin described in the patent documents of the background art.

Polyarylate resins having repeating units represented by the chemical formulas (R16) and (R17) (hereinafter, referred to as polyarylate resins (R16) and (R17), respectively) were prepared as binder resins used in comparative examples. The viscosity average molecular weights of both polyarylate resins (R16) and (R17) were 50000.

In the above chemical formulas (R13) to (R17), the lower right-hand number of each repeating unit represents the percentage (%) of the number of each repeating unit in the polycarbonate resin or polyarylate resin relative to the total number of repeating units contained.

(n-type pigment)

The azo pigments (a1) to (a4) and perylene pigments (P1) to (P3) described in the embodiment were prepared as n-type pigments.

< production of photoreceptor >

Photoreceptors (A-1) to (A-37) and (B-1) to (B-6) were produced using the charge generating agent, the electron transporting agent, the hole transporting agent, the binder resin and the n-type pigment described in < Material for Forming photosensitive layer > above.

(production of photoreceptor (A-1))

Using a ball mill, 3.00 parts by mass of Y-type oxytitanium phthalocyanine as a charge generator, 70.00 parts by mass of a hole transporting agent (HT1), 35.00 parts by mass of an electron transporting agent (ET1), 100.00 parts by mass of a polyarylate resin (R1) as a binder resin, 2.00 parts by mass of an azo pigment (a1) as an n-type pigment, and 800.00 parts by mass of tetrahydrofuran as a solvent were mixed for 50 hours to obtain a coating liquid for a photosensitive layer. The coating liquid for photosensitive layer was applied on a conductive substrate (aluminum drum-shaped support) by dip coating. The coating liquid for the photosensitive layer applied was dried with hot air at 120 ℃ for 60 minutes. Thus, a photosensitive layer (film thickness: 28 μm) was formed on the conductive substrate, and the photoreceptor (A-1) was obtained. In the photoreceptor (A-1), a single photosensitive layer is directly formed on a conductive substrate.

(production of photoreceptors (A-2) to (A-35) and (B-2) to (B-6))

Photoreceptors (A-2) to (A-35) and (B-2) to (B-6) were produced according to the production method of photoreceptor (A-1) except that the hole-transporting agent, the electron-transporting agent, the n-type pigment and the binder resin of the types shown in tables 5 and 6 were used.

(production of photoreceptors (A-36) to (A-37))

Photoreceptors (A-36) to (A-37) were produced in accordance with the production method for photoreceptor (A-1) except that the amount of azo pigment (A1) added was changed from 2.00 parts by mass to the amount shown in Table 6.

(production of photoreceptor (B-1))

Photoreceptor (B-1) was produced according to the method for producing photoreceptor (A-1) except that the n-type pigment was not added.

< evaluation >

The following evaluations were carried out for each of the photoreceptors (A-1) to (A-37) and (B-1) to (B-6) to be evaluated.

[ evaluation of abrasion resistance of photosensitive layer ]

The coating liquid for photosensitive layer prepared in < production of photoreceptor > above was coated on a polypropylene sheet wound with an aluminum tube. The coating liquid for the photosensitive layer applied was dried at 120 ℃ for 60 minutes to produce a polypropylene sheet having a photosensitive layer (film thickness of 28 μm). Subsequently, the photosensitive layer was peeled off from the polypropylene sheet. The peeled photosensitive layer was adhered to a card-like member (manufactured by TABER corporation, "S-36"). Measuring the mass of a card-like member to which a photosensitive layer is appliedM_A. Then, a card-like member was set on a rotary table of a rotary abrasion tester (manufactured by Toyo Seiki Seisaku-Sho Co., Ltd.). Subsequently, a grindstone (CS-10, manufactured by TABER) loaded at 500gf was placed on the photosensitive layer on the card-like member, and the rotary table was rotated at 60rpm for 500 revolutions. This causes abrasion of the photosensitive layer on the turntable. After the abrasion, the mass M of the card-like member to which the photosensitive layer is attached is measured again_B. Then, the amount of wear (═ M) of change in the mass of the photosensitive layer before and after the wear was determined_A-M_B). The abrasion resistance of the photoreceptor was evaluated from the abrasion amount based on the following criteria. The results of the abrasion resistance evaluation are shown in tables 5 and 6. The photoreceptor evaluated as having abrasion resistance was evaluated as having poor abrasion resistance.

(evaluation criteria for abrasion resistance)

Evaluation A: the abrasion loss is less than 5 mg.

Evaluation B: the abrasion loss is 5mg or more and less than 8 mg.

Evaluation C: the abrasion loss was 8mg or more.

[ evaluation of charging stability of photoreceptor ]

The evaluation environment of the charging stability of the photoreceptor was an environment at a temperature of 10 ℃ and a relative humidity of 15% RH. For the evaluation of the charging stability, an evaluation machine (a changer of "FS-C5250 DN" manufactured by Kyowa office information systems Co., Ltd.) was used. The evaluation machine was equipped with a grid corotron charger and a cleaning roller, and was not equipped with a cleaning blade. The charged polarity of the grid corotron charger is positive. The rotation speed of the photoreceptor was set so that the exposure-development time reached 70 msec.

First, an image a (full-area blank image) was printed on 3 sheets of a recording medium (a4 paper) using an evaluation machine. When each sheet is printed, the surface potential of the photoreceptor is measured at the development position. In addition, when printing a blank image, since exposure is not performed, the measured surface potential corresponds to a charged potential. The surface potential was measured 1 time for printing 1 sheet, 3 times in total. The average value of the measured surface potentials for 3 times was used as the charging potential V before the printing test₀₁(unit: + V).

Then, a printing test was performed. In the printing test, the printing of an image B (print pattern image with a print coverage of 5%) was performed on 10,000 recording media (a4 paper) using an evaluation machine every 15 seconds. Immediately after the end of the print test, printing of an image a (full-face blank image) was performed on 3 recording media (a4 paper sheets). When printing is performed on each sheet, the surface potential of the photoreceptor is measured at the development position. The surface potential was measured 1 time for printing 1 sheet, 3 times in total. The average value of the measured surface potentials for 3 times is used as the charged potential V after the printing test₀₂(unit: + V).

Charged potential V before printing test₀₁Subtracting the charged potential V after the printing test₀₂Value of (V)₀₁-V₀₂) As a decrease amount of charged potential Δ V₀(unit: V). According to the charge potential drop amount DeltaV₀The evaluation of the charging stability of the photoreceptor was performed based on the following criteria. The evaluation results of the charging stability are shown in tables 5 and 6. The photoreceptor evaluated as C in the charging stability, i.e., the photoreceptor evaluated as poor in the charging stability.

(evaluation criteria for Charge stability)

Evaluation A: charge potential drop amount Δ V₀Is 0V or more and less than 60V.

Evaluation B: charge potential drop amount Δ V₀Is 60V or more and less than 110V.

Evaluation C: charge potential drop amount Δ V₀Is 110V or more.

In tables 5 and 6, the meanings of the technical terms are as follows. "n-type" means an n-type pigment. "HTM" means a hole transporting agent. "ETM" means an electron transport agent. "resin" means a bonding resin. The "amount" in the column of "n-type" indicates the addition amount of the n-type pigment with respect to 3.00 parts by mass of the charge generating agent. "parts" means parts by mass. "none" means no such ingredient.

[ TABLE 5 ]

[ TABLE 6 ]

As shown in tables 5 and 6, the photosensitive layers of the photoreceptors (a-1) to (a-37) each contain 1 of polyarylate resins (R1) to (R12) as a binder resin. The polyarylate resins (R1) to (R12) are each a polyarylate resin of polyarylate resins (PA) containing at least 1 repeating unit (1) and at least 1 repeating unit (2). The photosensitive layers of the photoreceptors (a-1) to (a-37) each contain an n-type pigment (more specifically, 1 of azo pigments (a1) to (a4) and perylene pigments (P1) to (P3)). The abrasion resistance of the photoreceptors (A-1) to (A-37) was evaluated as A or B, and these photoreceptors were excellent in abrasion resistance. The photoreceptors (A-1) to (A-37) were evaluated for their charge stability as A or B, and the charge stability of these photoreceptors was good.

As described above, the photoreceptor according to the present invention exhibits excellent abrasion resistance and charging stability. The photoreceptor according to the present invention has excellent abrasion resistance and charging stability, and therefore, the process cartridge and the image forming apparatus having the photoreceptor according to the present invention have excellent durability and can form a high-quality image.

[ industrial availability ]

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

Claims

1. An electrophotographic photoreceptor is provided with a photosensitive layer containing a photosensitive compound,

comprises a conductive substrate and a photosensitive layer,

the photosensitive layer is a single layer of a photosensitive material,

the photosensitive layer contains a charge generator, a hole transporting agent, an electron transporting agent, a binder resin and an n-type pigment,

the binder resin contains a polyarylate resin having at least 1 repeating unit represented by the general formula (1) and at least 1 repeating unit represented by the general formula (2),

in the general formula (1), a represents 1 or 2,

in the general formula (2), X is a divalent group represented by the formula (X1), (X2), (X3), (X4) or (X5),

2. the electrophotographic photoreceptor according to claim 1,

the n-type pigment is an azo pigment.

3. The electrophotographic photoreceptor according to claim 2,

the azo pigment is represented by the formula (A1), (A2), (A3) or (A4),

4. the electrophotographic photoreceptor according to claim 1,

the n-type pigment is a perylene pigment.

5. The electrophotographic photoreceptor according to claim 4,

the perylene pigment is represented by the chemical formula (P1), (P2) or (P3),

6. the electrophotographic photoreceptor according to claim 1,

the content of the n-type pigment is 0.01 to 3.00 parts by mass with respect to 1.00 part by mass of the charge generating agent.

7. The electrophotographic photoreceptor according to claim 1,

the polyarylate resin is a polyarylate resin having repeating units represented by chemical formulas (1-2) and (2-X3),

or a polyarylate resin comprising the repeating units represented by the above chemical formula (1-2) and chemical formula (2-X5),

8. the electrophotographic photoreceptor according to claim 1,

the polyarylate resin is a polyarylate resin having a repeating unit represented by chemical formula (1-2), chemical formula (2-X1), and chemical formula (2-X4),

or a polyarylate resin comprising repeating units represented by the above chemical formula (1-2), the above chemical formula (2-X1), and the above chemical formula (2-X3),

or a polyarylate resin comprising repeating units represented by the following chemical formula (1-2), the following chemical formula (2-X4), and the following chemical formula (2-X3),

or a polyarylate resin comprising repeating units represented by the above chemical formula (1-2), the above chemical formula (2-X5), and the above chemical formula (2-X3),

or a polyarylate resin comprising repeating units represented by the following chemical formula (1-2), the following chemical formula (2-X5), and the following chemical formula (2-X1),

or a polyarylate resin comprising repeating units represented by the following chemical formula (1-1), the following chemical formula (2-X1), and the following chemical formula (2-X3),

9. the electrophotographic photoreceptor according to claim 1,

the polyarylate resin is a polyarylate resin having a repeating unit represented by chemical formula (1-1), chemical formula (1-2), chemical formula (2-X1), and chemical formula (2-X3),

10. the electrophotographic photoreceptor according to claim 1,

the charge generating agent contains metal-free phthalocyanine or metal phthalocyanine.

11. The electrophotographic photoreceptor according to claim 1,

the electron transport agent contains a compound represented by general formula (10), (11), (12), (13) or (14),

in the general formula (10), Q¹、Q²、Q³And Q⁴Independently of one another, represents a hydrogen atom, a C1-C6 alkyl group, a C1-C6 alkoxy group, a C6-C14 aryl group or a C7-C20 aralkyl group,

in the general formula (11), Q⁵Represents a C1-C6 alkyl group or a C6-C14 aryl group, Q⁶Represents C1-C6 alkyl, C6-C14 aryl, C1-C6 alkoxy, C7-C20 aralkyl, C6-C14 aryloxy or C7-C20 aralkyloxy, Q⁷Represents a C1-C6 alkyl group, v represents an integer of 0 to 4 inclusive,

in the general formula (12), Q⁸And Q⁹Independently of one another, represents a C6-C14 aryl group having at least one C1-C6 alkyl substituent or an unsubstituted C6-C14 aryl group,

in the general formula (13), Q¹⁰、Q¹¹、Q¹²And Q¹³Each independently represents a hydrogen atom, a C1-C6 alkyl group, a C2-C6 alkenyl group, a C1-C6 alkoxy group, a C6-C14 aryl group, a C7-C20 aralkyl group or a C3-C14 heterocyclic group,

12. The electrophotographic photoreceptor according to claim 1,

the hole-transporting agent contains a compound represented by the general formula (20), (21), (22), (23), (24), (25), (26) or (27),

in the general formula (20), R¹¹、R¹²、R¹³、R¹⁴、R¹⁵And R¹⁶Each independently represents C1-C8 alkyl or phenyl, R¹⁷And R¹⁸Each independently represents a hydrogen atom, a C1-C8 alkyl group or a phenyl group, b1, b2, b3 and b4 each independently represents an integer of 0 to 5, b5 and b6 each independently represents an integer of 0 to 4, d and e each independently represents 0 or 1,

in the general formula (21), R²⁰Represents a hydrogen atom, a C1-C8 alkyl group, a C1-C8 alkoxy group, a phenyl group having a C1-C8 alkyl substituent or an unsubstituted phenyl group, R²¹、R²²And R²³Independently represents a C1-C8 alkyl group or a C1-C8 alkoxy group, f1, f2 and f3 independently represent an integer of 0 to 5, f4 represents 0 or 1,

in the general formula (22), R³¹、R³²、R³³、R³⁴And R³⁵Independently represents a C1-C8 alkyl group or a C1-C8 alkoxy group, g1, g2, g3, g4 and g5 independently represent an integer of 0 to 5,

in the general formula (23), R⁴¹、R⁴²、R⁴³、R⁴⁴、R⁴⁵And R⁴⁶Independently represents C1-C8 alkyl, phenyl or C1-C8 alkoxy, h1, h2, h4 and h5 independently represent an integer of 0 to 5, and h3And h6 each independently represents an integer of 0 to 4 inclusive,

in the general formula (24), R⁶¹、R⁶²And R⁶³Each independently represents a C1-C8 alkyl group, R⁶⁴、R⁶⁵And R⁶⁶Each independently represents a hydrogen atom or a C1-C8 alkyl group,

in the general formula (25), R⁷¹、R⁷²、R⁷³And R⁷⁴Independently represents a C1-C8 alkyl group, j1, j2, j3 and j4 independently represent an integer of 0 to 5, j5 represents 0 or 1,

in the general formula (26), R⁸¹、R⁸²And R⁸³Each independently represents C1-C8 alkyl, phenyl or C1-C8 alkoxy, R⁸⁴And R⁸⁵Each independently represents a phenyl group having a C1-C8 alkyl substituent, an unsubstituted phenyl group, a hydrogen atom, a C1-C8 alkyl group or a C1-C8 alkoxy group, each of k1, k2 and k3 independently represents an integer of 0 to 5, each of k4 and k5 independently represents 1 or 2,

in the general formula (27), R⁹¹、R⁹²And R⁹³Each independently represents a C1-C8 alkyl group, R⁹⁴Represents a C1-C8 alkyl group or a hydrogen atom, and v1, v2 and v3 each independently represent an integer of 0 to 5.

13. The electrophotographic photoreceptor according to claim 1,

the hole transporting agent contains a compound represented by the formula (HT1), (HT2), (HT3), (HT4), (HT5), (HT6), (HT7), (HT8), (HT9), (HT10), (HT11), (HT12), (HT13), or (HT14),

14. a kind of processing box is disclosed, which comprises a box body,

the electrophotographic photoreceptor according to claim 1.

15. An image forming apparatus includes:

an image carrier provided rotatably;

a charging device for charging the surface of the image carrier to a positive polarity;

an exposure device configured to irradiate the surface of the charged image carrier with light to form an electrostatic latent image on the surface of the image carrier;

a developing device that develops the electrostatic latent image into a toner image; and

a transfer device for transferring the toner image from the image bearing member to a transfer object,

the image bearing member is the electrophotographic photoreceptor according to claim 1.