JP6658664B2 - Electrophotographic photoreceptor, process cartridge and image forming apparatus - Google Patents

Description

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

  The electrophotographic photosensitive member is used as an image carrier in an electrophotographic image forming apparatus (for example, a printer and a multifunction peripheral). The electrophotographic photoreceptor includes a photosensitive layer. Examples of the electrophotographic photoconductor include a single-layer electrophotographic photoconductor and a laminated electrophotographic photoconductor. The single-layer type electrophotographic photoreceptor includes a photosensitive layer having a charge generation function and a charge transport function. The layered electrophotographic photoreceptor includes a photosensitive layer including a charge generation layer having a charge generation function and a charge transport layer having a charge transport function.

  Patent Document 1 describes an electrophotographic photosensitive member containing a polyarylate resin represented by the following chemical formula (RA).

JP-A-10-288845

  However, the electrophotographic photosensitive member described in Patent Literature 1 does not have sufficient transferability of a toner image (hereinafter, may be referred to as transferability) and filming resistance.

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

  The electrophotographic photoreceptor of the present invention includes a conductive substrate and a photosensitive layer. The photosensitive layer has a charge generation layer and a charge transport layer. The charge generation layer contains a charge generation agent. The charge transport layer includes a hole transport agent, a binder resin, and a carboxylic anhydride. The binder resin includes a polyarylate resin. The polyarylate resin has a repeating unit represented by the following general formula (1), general formula (2) or general formula (3). The carboxylic anhydride is a compound represented by the following general formula (4), general formula (5), general formula (6) or general formula (7). The content of the carboxylic anhydride is 0.02 to 8.00 parts by mass based on 100.00 parts by mass of the binder resin.

In the general formula (1), k represents 2 or 3. In the general formulas (1), (2) and (3), X, Y and Z are each independently the following chemical formulas (1A), (1B), (1C) and (1D) ), A divalent group represented by chemical formula (1E), chemical formula (1F) or chemical formula (1G). Q ¹ , Q ² , Q ³ and Q ⁴ each independently represent a methyl group or a hydrogen atom.

In the general formulas (4), (5) and (6), R ¹ , R ² , R ³ and R ⁴ each independently have 1 or more carbon atoms which may have a substituent. It represents an alkyl group having 6 or less, an alkoxy group having 1 to 6 carbon atoms which may have a substituent, an aryl group having 6 to 14 carbon atoms which may have a substituent, or a halogen atom. a1 and a2 each independently represent an integer of 0 or more and 3 or less. a3 represents an integer of 0 or more and 2 or less. a4 represents an integer of 0 or more and 4 or less. If a1 is representing two or three, more of R ¹ may be the same or different from each other. When a2 represents 2 or 3, a plurality of R ² may be the same or different. If a3 is 2, two R ³ may be the same or different from each other. If a4 represents an integer of 2 to 4, a plurality of R ⁴ may be the same or different from each other. In the general formula (7), G represents a single bond or an oxygen atom.

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

  The image forming apparatus according to the present invention includes an image carrier, a charging unit, an exposure unit, a development unit, and a transfer unit. The image bearing member is the above-described electrophotographic photosensitive member. The charging unit charges the surface of the image carrier. The exposure section exposes the charged surface of the image carrier to form an electrostatic latent image on the surface of the image carrier. The developing unit develops the electrostatic latent image as a toner image. The transfer unit transfers the toner image from the image carrier to the transfer body while bringing the surface of the image carrier into contact with the transfer body.

  The electrophotographic photoreceptor of the present invention can improve transferability and filming resistance. Further, the process cartridge and the image forming apparatus of the present invention can suppress the occurrence of image defects.

FIG. 2 is a partial cross-sectional view illustrating an example of the structure of the electrophotographic photosensitive member according to the first embodiment of the present invention. FIG. 2 is a partial cross-sectional view illustrating an example of the structure of the electrophotographic photosensitive member according to the first embodiment of the present invention. FIG. 2 is a partial cross-sectional view illustrating an example of the structure of the electrophotographic photosensitive member according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating an example of an image forming apparatus according to a second embodiment of the present invention. FIG. 4 is a diagram illustrating an image in which an image defect has occurred. It is a figure showing an example of composition of a scratching device. FIG. 7 is a sectional view taken along line IV-IV in FIG. 6. FIG. 7 is a side view of the fixing stand, the scratching needle, and the electrophotographic photosensitive member shown in FIG. 6. FIG. 3 is a diagram showing a scratch formed on the surface of a photosensitive layer. It is a figure showing the design image of the evaluation image used for evaluation of transfer nature.

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the present invention. In addition, although the description may be omitted as appropriate for portions where the description is duplicated, this does not limit the gist of the invention. In the present specification, a compound and its derivative may be generically referred to by adding “system” after the compound name. When a polymer name is represented by adding “system” after the compound name, it means that the repeating unit of the polymer is derived from the compound or its derivative.

  Hereinafter, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, and a halogen atom have the following meanings, respectively.

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

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

  An aryl group having 6 to 14 carbon atoms is unsubstituted. Examples of the aryl group having 6 to 14 carbon atoms include an unsubstituted aromatic monocyclic hydrocarbon group having 6 to 14 carbon atoms and an unsubstituted fused aromatic bicyclic group having 6 to 14 carbon atoms. Examples include a hydrocarbon group and an unsubstituted fused aromatic tricyclic hydrocarbon group having 6 to 14 carbon atoms. More specific examples of the aryl group having 6 to 14 carbon atoms include a phenyl group, a naphthyl group, an anthryl group, and a phenanthryl group.

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

  In the following description, “may have a substituent” means that part or all of the hydrogen atoms of the functional group may be substituted with a substituent.

<First Embodiment: Electrophotographic Photoreceptor>
The structure of the electrophotographic photosensitive member according to the first embodiment of the present invention (hereinafter, sometimes referred to as a photosensitive member) will be described. FIGS. 1, 2 and 3 are partial cross-sectional views showing the structure of the photoconductor 1 as an example of the first embodiment. As shown in FIG. 1, the photoconductor 1 includes a conductive substrate 2 and a photosensitive layer 3. The photosensitive layer 3 includes a charge generation layer 3a and a charge transport layer 3b.

  As shown in FIG. 2, the photoreceptor 1 may be provided with a charge transport layer 3b on a conductive substrate 2 and a charge generation layer 3a on the charge transport layer 3b. However, since the thickness of the charge transport layer 3b is generally thicker than the thickness of the charge generation layer 3a, the charge transport layer 3b is less likely to be damaged than the charge generation layer 3a. Therefore, in order to improve the wear resistance of the photoreceptor 1, as shown in FIG. 1, the charge generation layer 3a is provided on the conductive substrate 2, and the charge transport layer 3b is provided on the charge generation layer 3a. Is preferred.

  As shown in FIG. 3, the photoconductor 1 may include a conductive substrate 2, a photosensitive layer 3, and an intermediate layer 4 (for example, an undercoat layer). The intermediate layer 4 is provided between the conductive substrate 2 and the photosensitive layer 3. Further, a protective layer (not shown) may be provided on the photosensitive layer 3.

  The elastic power of the photosensitive layer 3 is preferably 45.0% or more, and more preferably 47.0% or more, from the viewpoint of further improving the filming resistance.

The elastic power of the photosensitive layer 3 is measured by performing the following steps A, B and C using a microhardness meter equipped with a diamond indenter in an environment of a temperature of 23 ° C. and a humidity of 50% RH. You. In step A, a load is applied to the photosensitive layer 3 using a diamond indenter over a period of 30 seconds so that the maximum load becomes 9.8 mN, and the maximum deformation work (EW ₁ : (Work of plastic deformation + Work of elastic deformation). In step B, the diamond indenter is separated from the photosensitive layer 3 over 30 seconds to remove the load applied to the photosensitive layer 3, and the restoration amount (EW ₂ : work of elastic deformation) of the photosensitive layer 3 when the load is removed. ) Is measured. In step C, from the measured maximum deformation work amount (EW ₁ ) of the photosensitive layer 3 and the restoration amount (EW ₂ ) of the photosensitive layer 3, the expression “elastic power (%) = (100 × EW ₂ ) / EW ₁ ", The elastic power of the photosensitive layer 3 is determined.

  The outline of the method for measuring the elastic power of the photosensitive layer 3 has been described above. The method for measuring the elastic power of the photosensitive layer 3 will be described in detail in Examples. The elastic power of the photosensitive layer 3 can be controlled, for example, by adjusting the type of a polyarylate resin described later and the type and content of a carboxylic anhydride described later.

  The scratch depth of the photosensitive layer 3 is preferably 1.00 μm or less, more preferably 0.70 μm or less, and further preferably 0.50 μm or less, from the viewpoint of further improving the filming resistance. preferable.

  The scratching depth of the photosensitive layer 3 is measured by performing the following first step, second step, third step, and fourth step using a scratching device specified in JIS K5600-5-5. You. The scratching device includes a fixed base and a scratching needle. The scratching needle has a hemispherical sapphire tip with a diameter of 1 mm.

  In the first step, the photoconductor 1 is fixed on the upper surface of the fixing base such that the longitudinal direction of the photoconductor 1 is parallel to the longitudinal direction of the fixing base. In the second step, the scratching needle is brought into perpendicular contact with the surface of the photosensitive layer 3. In the third step, while applying a load of 10 g to the photosensitive layer 3 from the scratching needle, the fixed member and the photosensitive member 1 fixed on the upper surface of the fixed member are moved 30 mm in the longitudinal direction of the fixed member at a speed of 30 mm / min. Let it. By this third step, a scratch is formed on the surface of the photosensitive layer 3. In the fourth step, the maximum depth of the scratch is measured.

  The outline of the method for measuring the scratch depth of the photosensitive layer 3 has been described above. The method of measuring the scratch depth of the photosensitive layer 3 will be described in detail in Examples. The scratch depth of the photosensitive layer 3 can be controlled, for example, by adjusting the type of a polyarylate resin described later and the type and content of a carboxylic anhydride described later.

  The thickness of the charge generation layer 3a and the charge transport layer 3b is not particularly limited as long as the function as each layer can be sufficiently exhibited. The thickness of the charge generation layer 3a is preferably 0.01 μm or more and 5 μm or less, and more preferably 0.1 μm or more and 3 μm or less. The thickness of the charge transport layer 3b is preferably 2 μm or more and 100 μm or less, more preferably 5 μm or more and 50 μm or less. The structure of the photoconductor 1 has been described above with reference to FIGS.

  Hereinafter, the components (conductive substrate, photosensitive layer, and intermediate layer) of the photoconductor according to the present embodiment will be described. Further, a method for manufacturing the photoconductor will be described.

[1. Conductive substrate]
The conductive substrate is not particularly limited as long as it can be used as a conductive substrate of the photoreceptor. As the conductive substrate, a conductive substrate including at least a surface portion made of a conductive material can be used. As an example of the conductive substrate, a conductive substrate formed of a material having conductivity (conductive material) can be given. Another example of a conductive substrate includes a conductive substrate coated with a conductive material. Examples of the conductive material include aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, and indium. Among these conductive materials, one kind may be used alone, or two or more kinds may be used in combination. As a combination of two or more, for example, an alloy (more specifically, an aluminum alloy, stainless steel, brass, or the like) can be given. Among these conductive materials, aluminum and an aluminum alloy are preferable.

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

[2. Photosensitive layer]
(Charge generation layer)
The charge generation layer contains a charge generation agent. Further, the charge generation layer may contain a binder resin for a charge generation layer (hereinafter, sometimes referred to as a base resin) and an additive.

(Charge generator)
The charge generator is not particularly limited as long as it is a charge generator for a photoreceptor. As the charge generating agent, for example, phthalocyanine pigments, perylene pigments, bisazo pigments, trisazo pigments, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, indigo pigments, azurenium pigments, cyanine Pigments, powders of inorganic photoconductive materials (more specifically, selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, amorphous silicon, etc.), pyrylium pigments, anthanthrone-based pigments, triphenylmethane-based pigments, sulene-based pigments , Toluidine pigments, pyrazoline pigments and quinacridone pigments. The charge generator may be used alone or in combination of two or more.

  Examples of the phthalocyanine-based pigment include a metal-free phthalocyanine and a metal phthalocyanine represented by the following chemical formula (C-1). Examples of the metal phthalocyanine include titanyl phthalocyanine and hydroxygallium phthalocyanine represented by the following chemical formula (C-2). The phthalocyanine-based pigment may be crystalline or non-crystalline. The crystal shape (for example, α-type, β-type, X-type, Y-type, V-type and II-type) of the phthalocyanine-based pigment is not particularly limited, and phthalocyanine-based pigments having various crystal shapes are used.

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

  For example, in a digital optical image forming apparatus (for example, a laser beam printer and a facsimile using a light source such as a semiconductor laser), it is preferable to use a photoconductor having sensitivity in a wavelength region of 700 nm or more. As the charge generating agent in this case, a phthalocyanine-based pigment is preferable because it has a high quantum yield in a wavelength region of 700 nm or more, and metal-free phthalocyanine and titanyl phthalocyanine are more preferable, and X-type metal-free phthalocyanine and Y-type titanyl phthalocyanine are used. Is more preferred.

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

  An example of a method for measuring a CuKα characteristic X-ray diffraction spectrum will be described. A sample (titanyl phthalocyanine) is filled in a sample holder of an X-ray diffractometer (for example, “RINT (registered trademark) 1100” manufactured by Rigaku Corporation), and an X-ray tube Cu, a tube voltage of 40 kV, a tube current of 30 mA and CuKα An X-ray diffraction spectrum is measured under the condition of a characteristic X-ray wavelength of 1.542 °. The measurement range (2θ) is, for example, not less than 3 ° and not more than 40 ° (start angle 3 °, stop angle 40 °), and the scanning speed is, for example, 10 ° / min.

  The content of the charge generating agent is, for example, preferably from 5 parts by mass to 1,000 parts by mass, and more preferably from 30 parts by mass to 500 parts by mass, based on 100 parts by mass of the base resin contained in the charge generating layer. Is more preferred.

(Base resin)
The base resin is not particularly limited as long as it is a resin for the charge generation layer. Examples of the base resin include a thermoplastic resin, a thermosetting resin, and a photocurable resin. As the thermoplastic resin, for example, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic acid copolymer, styrene-acrylic acid copolymer, polyethylene resin, ethylene-acetic acid Vinyl copolymer, chlorinated polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer, vinyl chloride-vinyl acetate copolymer, alkyd resin, polyamide resin, urethane resin, polysulfone resin, diallyl phthalate resin, ketone resin, polyvinyl acetal Resins, polyvinyl butyral resins, polyether resins, polycarbonate resins, polyarylate resins, and polyester resins. Examples of the thermosetting resin include a silicone resin, an epoxy resin, a phenol resin, a urea resin, a melamine resin, and other crosslinkable thermosetting resins. Examples of the photocurable resin include an epoxy-acrylic acid-based resin (an acrylic acid adduct of an epoxy compound) and a urethane-acrylic acid copolymer (an acrylic acid adduct of a urethane compound). As the base resin, a polyvinyl acetal resin is preferably used. As the base resin, one type may be used alone, or two or more types may be used in combination.

  Further, as the base resin, a resin different from a binder resin described later is preferable. This is because, when the photoreceptor is manufactured, for example, since the coating solution for the charge transport layer is applied on the charge generation layer, the charge generation layer is preferably not dissolved in the solvent of the coating solution for the charge transport layer.

(Charge transport layer)
The charge transporting layer contains a hole transporting agent, a binder resin, and a carboxylic anhydride (hereinafter sometimes referred to as an acid anhydride). The charge transport layer may contain one or both of an electron acceptor compound and an additive as needed.

(Hole transport agent)
Examples of the hole transport agent include a nitrogen-containing cyclic compound and a condensed polycyclic compound. Examples of the nitrogen-containing cyclic compound and the condensed polycyclic compound include a triphenylamine derivative; a diamine derivative (more specifically, an N, N, N ′, N′-tetraphenylbenzidine derivative, N, N, N ', N'-tetraphenylphenylenediamine derivative, N, N, N', N'-tetraphenylnaphthylenediamine derivative, di (aminophenylethenyl) benzene derivative, N, N, N ', N'-tetraphenyl Oxadiazole-based compounds (more specifically, 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole and the like); styryl-based compounds (more Specifically, 9- (4-diethylaminostyryl) anthracene and the like); carbazole-based compounds (more specifically, polyvinyl carbazole and the like); Pyrazoline compounds (more specifically, 1-phenyl-3- (p-dimethylaminophenyl) pyrazolin etc.); hydrazone compounds; indole compounds; oxazole compounds; isoxazole compounds; thiazole compounds A thiadiazole compound; an imidazole compound; a pyrazole compound; and a triazole compound. One of these hole transport agents may be used alone, or two or more thereof may be used in combination.

  As the hole transport agent, from the viewpoint of efficiently transporting holes, a compound represented by the following general formula (11) is preferable, and a compound represented by the following chemical formula (HTM11) (hereinafter, a hole transport agent (HTM11)) )) Is more preferable.

In the general formula (11), Q ⁸ , Q ¹⁰ , Q ¹¹ , Q ¹² , Q ¹³ and Q ¹⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and a carbon atom having 1 to 6 carbon atoms. It represents the following alkoxy group or phenyl group. Q ⁹ and Q ¹⁵ each independently represent an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. b represents an integer of 0 or more and 5 or less. c represents an integer of 0 or more and 4 or less. When b represents an integer of 2 to 5, a plurality of Q ⁹ bonded to the same phenyl group may be the same or different. When c represents an integer of 2 to 4, a plurality of Q ¹⁵ bonded to the same phenylene group may be the same or different. m represents 0 or 1.

  The content of the hole transporting agent is preferably from 10 parts by mass to 200 parts by mass, and more preferably from 10 parts by mass to 100 parts by mass with respect to 100 parts by mass of the binder resin, from the viewpoint of efficiently transporting holes. Is more preferable.

(Binder resin)
The binder resin includes a polyarylate resin having a repeating unit represented by the following general formula (1), general formula (2) or general formula (3). Hereinafter, the polyarylate resins having the repeating units represented by the general formulas (1) to (3) may be referred to as polyarylate resins (1) to (3), respectively. Further, the polyarylate resins (1) to (3) may be collectively described as a polyarylate resin R. The charge transport layer can include one or more of polyarylate resins (1) to (3). From the viewpoint of further improving transferability and filming resistance, the binder resin preferably contains at least one of the polyarylate resin (1) and the polyarylate resin (2).

In the general formula (1), k represents 2 or 3. In the general formulas (1), (2) and (3), X, Y and Z are each independently the following chemical formulas (1A), (1B), (1C) and (1D) , A divalent group represented by chemical formula (1E), chemical formula (1F) or chemical formula (1G). Q ¹ , Q ² , Q ³ and Q ⁴ each independently represent a methyl group or a hydrogen atom.

  Hereinafter, the polyarylate resins (1) to (3) will be described in detail.

(Polyarylate resin (1))
As the polyarylate resin (1), for example, a polyarylate resin having a repeating unit represented by the following general formula (1-A) (hereinafter sometimes referred to as polyarylate resin (1-A)) is used. it can.

In the general formula (1-A), ka and kb each independently represent 2 or 3. X ^a and X ^b are each independently represented by chemical formula (1A), chemical formula (1B), chemical formula (1C), chemical formula (1D), chemical formula (1E), chemical formula (1F) or chemical formula (1G). Is a valence group. s ¹ represents a number from 1 to 100. u ¹ represents a number from 0 to 99. s ¹ + u ¹ = 100.

In the general formula (1-A), ka and kb preferably represent 3 from the viewpoint of further improving transferability and filming resistance. From the same viewpoint, X ^a and X ^b are preferably each independently a divalent group represented by the chemical formula (1A), the chemical formula (1C), the chemical formula (1F), or the chemical formula (1G), More preferably, it is a divalent group represented by (1A), chemical formula (1F) or chemical formula (1G).

When u ¹ in the general formula (1-A) is 0, X ^a is a divalent group represented by the chemical formula (1G) from the viewpoint of further improving transferability and filming resistance. Is preferred. When u ¹ is not 0, from the viewpoint of further improving transferability and filming resistance, X ^a is ^a divalent group represented by the chemical formula (1A), and X ^b is represented by the chemical formula (1F). It is preferably a divalent group. When u ¹ is not 0, it is preferable that s ¹ and u ¹ each independently represent a number of 30 or more and 70 or less from the viewpoint of further improving transferability and filming resistance.

  The polyarylate resin (1-A) includes, for example, a repeating unit represented by the following general formula (1-A-1) (hereinafter, sometimes referred to as a repeating unit (1-A-1)), and the following: It has a repeating unit represented by the general formula (1-A-2) (hereinafter sometimes referred to as a repeating unit (1-A-2)).

Ka and X ^a in the general formula (1-A-1) is respectively the same as the ka and X ^a in formula (1-A). Kb and X ^b in the general formula (1-A-2) is the same meanings as defined kb and X ^b in formula (1-A).

  The polyarylate resin (1-A) may have a repeating unit other than the repeating units (1-A-1) and (1-A-2). The ratio (molar fraction) of the total amount of the repeating units (1-A-1) and (1-A-2) to the total amount of the repeating units in the polyarylate resin (1-A) is 0. .80 or more is preferred, 0.90 or more is more preferred, and 1.00 is even more preferred.

If u ¹ of formula (1-A) in is not 0, polyarylate resin (1-A) repeating units in (1-A-1) and the sequence of (1-A-2) is not particularly limited. That is, the polyarylate resin (1-A) may be any copolymer such as a random copolymer, an alternating copolymer, a periodic copolymer, and a block copolymer. Examples of the random copolymer include a copolymer in which repeating units (1-A-1) and repeating units (1-A-2) are randomly arranged. Examples of the alternating copolymer include a copolymer in which repeating units (1-A-1) and repeating units (1-A-2) are alternately arranged. Examples of the periodic copolymer include a copolymer in which one or more repeating units (1-A-1) and one or more repeating units (1-A-2) are periodically arranged. Is mentioned. Examples of the block copolymer include a copolymer in which a block composed of a plurality of repeating units (1-A-1) and a block composed of a plurality of repeating units (1-A-2) are arranged.

In addition, s ¹ in the general formula (1-A) represents the number of repeating units (1-A-1) and the number of repeating units (1-A-2) contained in the polyarylate resin (1-A). Represents the percentage of the number of repeating units (1-A-1) with respect to the sum of. U ¹ in the general formula (1-A) is the sum of the number of repeating units (1-A-1) and the number of repeating units (1-A-2) contained in the polyarylate resin (1-A). Represents the percentage of the number of repeating units (1-A-2) with respect to. Each of s ¹ and u ^{1 in} the general formula (1-A) is not a value obtained from one molecular chain, but the entire polyarylate resin (1-A) (a plurality of molecules) contained in the photosensitive layer. Chain).

  As the repeating unit (1-A-1) and the repeating unit (1-A-2), from the viewpoint of further improving transferability and filming resistance, the following chemical formulas (1-1) and (1-2) And at least one selected from the repeating units represented by the chemical formula (1-3).

(Polyarylate resin (2))
As the polyarylate resin (2), for example, a polyarylate resin having a repeating unit represented by the following general formula (2-A) (hereinafter sometimes referred to as polyarylate resin (2-A)) is used. it can.

In the general formula (2-A), Q ^1a , Q ^2a , Q ^1b and Q ^2b each independently represent a methyl group or a hydrogen atom. Y ^a and Y ^b are each independently formula (1A), the formula (1B), the formula (1C), the formula (1D), the formula (1E), two of formula (1F) or formula (1G) Is a valence group. s ² represents a number from 1 to 100. u ² represents a number from 0 to 99. s ² + u ² = 100.

In the general formula (2-A), Q ^1a , Q ^2a , Q ^1b and Q ^2b preferably represent a hydrogen atom from the viewpoint of further improving transferability and filming resistance. From the same viewpoint, Y ^a and Y ^b are each independently formula (1A), the formula (1C), it is a divalent group represented by the formula (1F) or formula (1G) Preferably, the chemical formula More preferably, it is a divalent group represented by (1C) or the chemical formula (1F).

From the viewpoint of further improving the transferability and filming resistance, in the general formula (2-A), a divalent group Y ^a is represented by the chemical formula (1C), and Y ^b is the formula (1F ) Is preferable. From the viewpoint of further improving transferability and filming resistance, it is preferable that s ² and u ² each independently represent a number of 30 or more and 70 or less.

  The polyarylate resin (2-A) includes, for example, a repeating unit represented by the following general formula (2-A-1) (hereinafter sometimes referred to as a repeating unit (2-A-1)), and the following: It has a repeating unit represented by the general formula (2-A-2) (hereinafter, sometimes referred to as a repeating unit (2-A-2)).

Formula (2-A-1) in the Q ^1a, Q ^2a and Y ^a is, Q ^1a, respectively in the general formula (2-A), the same meaning as Q ^2a and Y ^a. Formula (2-A-2) in the Q ^1b, Q ^2b and Y ^b is, Q ^1b, respectively in formula (2-A), the same meaning as Q ^2b and Y ^b.

  The polyarylate resin (2-A) may have a repeating unit other than the repeating units (2-A-1) and (2-A-2). The ratio (molar fraction) of the total amount of the repeating units (2-A-1) and (2-A-2) to the total amount of the repeating units in the polyarylate resin (2-A) is 0. .80 or more is preferred, 0.90 or more is more preferred, and 1.00 is even more preferred.

If u ² in formula (2-A) is not 0, polyarylate resin (2-A) repeating units in (2-A-1) and the sequence of (2-A-2) is not particularly limited. That is, the polyarylate resin (2-A) may be any copolymer such as a random copolymer, an alternating copolymer, a periodic copolymer, and a block copolymer. Examples of the random copolymer include a copolymer in which repeating units (2-A-1) and repeating units (2-A-2) are randomly arranged. Examples of the alternating copolymer include a copolymer in which repeating units (2-A-1) and repeating units (2-A-2) are alternately arranged. Examples of the periodic copolymer include a copolymer in which one or more repeating units (2-A-1) and one or more repeating units (2-A-2) are periodically arranged. Is mentioned. Examples of the block copolymer include a copolymer in which blocks composed of a plurality of repeating units (2-A-1) and blocks composed of a plurality of repeating units (2-A-2) are arranged.

In addition, s ² in the general formula (2-A) represents the number of repeating units (2-A-1) and the number of repeating units (2-A-2) contained in the polyarylate resin (2-A). Represents the percentage of the number of repeating units (2-A-1) with respect to the sum of U ² in the general formula (2-A) is the sum of the number of repeating units (2-A-1) and the number of repeating units (2-A-2) contained in the polyarylate resin (2-A). Represents the percentage of the number of repeating units (2-A-2) with respect to. Each of s ² and u ^{2 in} the general formula (2-A) is not a value obtained from one molecular chain, but the whole (a plurality of molecules) of the polyarylate resin (2-A) contained in the photosensitive layer. Chain).

  From the viewpoint of further improving transferability and filming resistance, the repeating unit (2-A-1) is a repeating unit represented by the following chemical formula (2-1), and the repeating unit (2-A-2) Is preferably a repeating unit represented by the following chemical formula (2-2).

(Polyarylate resin (3))
As the polyarylate resin (3), for example, a polyarylate resin having a repeating unit represented by the following general formula (3-A) (hereinafter sometimes referred to as polyarylate resin (3-A)) is used. it can.

In formula (3-A), Q ^3a , Q ^4a , Q ^3b and Q ^4b each independently represent a methyl group or a hydrogen atom. Z ^a and Z ^b are each independently formula (1A), the formula (1B), the formula (1C), the formula (1D), two of Formula (1E), the formula (1F) or formula (1G) Is a valence group. s ³ represents a number from 1 to 100. u ³ represents a number from 0 to 99. s ³ + u ³ = 100.

In formula (3-A), Q ^3a , Q ^4a , Q ^3b and Q ^4b preferably represent a methyl group from the viewpoint of further improving transferability and filming resistance. From the same viewpoint, Z ^a and Z ^b are each independently formula (1A), the formula (1C), it is a divalent group represented by the formula (1F) or formula (1G) Preferably, the chemical formula More preferably, it is a divalent group represented by (1C) or the chemical formula (1F).

From the viewpoint of further improving the transferability and filming resistance, in the general formula (3-A), a divalent group Z ^a is represented by the chemical formula (1C), and Z ^b is the formula (1F ) Is preferable. From the viewpoint of further improving transferability and filming resistance, it is preferable that s ³ and u ³ each independently represent a number of 30 or more and 70 or less.

  The polyarylate resin (3-A) includes, for example, a repeating unit represented by the following general formula (3-A-1) (hereinafter sometimes referred to as a repeating unit (3-A-1)), and the following: It has a repeating unit represented by the general formula (3-A-2) (hereinafter, sometimes referred to as a repeating unit (3-A-2)).

Formula (3-A-1) in the Q ^3a, Q ^4a and Z ^a is, Q ^3a, respectively in formula (3-A), the same meaning as Q ^4a and Z ^a. Q ^3b, Q ^4b and Z ^b in general formula (3-A-2) in the, Q ^3b, respectively in the general formula (3-A), the same meaning as Q ^4b and Z ^b.

  The polyarylate resin (3-A) may have a repeating unit other than the repeating units (3-A-1) and (3-A-2). The ratio (molar fraction) of the total amount of the repeating units (3-A-1) and (3-A-2) to the total amount of the repeating units in the polyarylate resin (3-A) is 0. .80 or more is preferred, 0.90 or more is more preferred, and 1.00 is even more preferred.

If the formula ^(3-A) u 3 in is not 0, polyarylate repeating units in the resin (3-A) (3- A-1) and the sequence of (3-A-2) is not particularly limited. That is, the polyarylate resin (3-A) may be any copolymer such as a random copolymer, an alternating copolymer, a periodic copolymer, and a block copolymer. Examples of the random copolymer include a copolymer in which repeating units (3-A-1) and repeating units (3-A-2) are randomly arranged. Examples of the alternating copolymer include a copolymer in which repeating units (3-A-1) and repeating units (3-A-2) are alternately arranged. Examples of the periodic copolymer include a copolymer in which one or more repeating units (3-A-1) and one or more repeating units (3-A-2) are periodically arranged. Is mentioned. Examples of the block copolymer include a copolymer in which a block composed of a plurality of repeating units (3-A-1) and a block composed of a plurality of repeating units (3-A-2) are arranged.

Incidentally, s ³ of the formula (3-A) in the the number of the number of repeating units (3-A-2) of the repeating units contained in the polyarylate resin (3-A) (3- A-1) Represents the percentage of the number of repeating units (3-A-1) with respect to the sum of U ³ in the general formula (3-A) is the sum of the number of repeating units (3-A-1) and the number of repeating units (3-A-2) contained in the polyarylate resin (3-A). Represents the percentage of the number of repeating units (3-A-2) with respect to. Each of s ³ and u ^{3 in} the general formula (3-A) is not a value obtained from one molecular chain, but the whole (a plurality of molecules) of the polyarylate resin (3-A) contained in the photosensitive layer. Chain).

  From the viewpoint of further improving transferability and filming resistance, the repeating unit (3-A-1) is a repeating unit represented by the following chemical formula (3-1), and the repeating unit (3-A-2) Is preferably a repeating unit represented by the following chemical formula (3-2).

  The binder resin may contain a resin (other resin) other than the polyarylate resin R. Other resins include, for example, thermoplastic resins (polyarylate resins other than polyarylate resin R, polycarbonate resins, styrene resins, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers) , Styrene-acrylic acid copolymer, acrylic copolymer, polyethylene resin, ethylene-vinyl acetate copolymer, chlorinated polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer, vinyl chloride-vinyl acetate copolymer, polyester Resin, alkyd resin, polyamide resin, polyurethane resin, polysulfone resin, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, polyester resin, etc., thermosetting resin (silicone resin, epoxy resin, pheno resin) Le resins, urea resins, melamine resins, and the like other than these crosslinking thermosetting resin), and a photocurable resin (epoxy - acrylic resins, urethane - acrylate copolymers, etc.). These may be used alone or in combination of two or more. The content of the polyarylate resin R is preferably at least 80% by mass, more preferably at least 90% by mass, even more preferably 100% by mass, based on the total amount of the binder resin.

  The viscosity average molecular weight of the binder resin is preferably 10,000 or more, more preferably 20,000 or more, still more preferably 30,000 or more, from the viewpoint of further improving filming resistance. It is particularly preferred that it is 40,000 or more. On the other hand, the viscosity average molecular weight of the binder resin is preferably 80,000 or less, more preferably 70,000 or less. When the viscosity average molecular weight of the binder resin is 80,000 or less, the binder resin tends to be easily dissolved in the solvent when forming the charge transport layer, and the charge transport layer tends to be easily formed.

  The method for producing the binder resin is not particularly limited as long as the polyarylate resin R can be produced. Examples of the method for producing the binder resin include a method of polycondensing an aromatic diol and an aromatic dicarboxylic acid for constituting a repeating unit of the polyarylate resin R. The method for condensation polymerization of the aromatic diol and the aromatic dicarboxylic acid is not particularly limited, and a known synthesis method (more specifically, solution polymerization, melt polymerization, interfacial polymerization, etc.) can be employed.

The aromatic dicarboxylic acid for producing the polyarylate resin R has two carboxyl groups. The aromatic dicarboxylic acid for producing the polyarylate resin (1-A) is represented by, for example, the following general formula (1-A-10) or general formula (1-A-20). The aromatic dicarboxylic acid for producing the polyarylate resin (2-A) is represented, for example, by the following general formula (2-A-10) or general formula (2-A-20). The aromatic dicarboxylic acid for producing the polyarylate resin (3-A) is represented by, for example, the following general formula (3-A-10) or general formula (3-A-20). X ^a, and X ^b in the formula (1-A-20) of the general formula (1-A-10) in is the same meaning as X ^a and X ^b in formula (1-A). Y ^b in the general formula (2-A-10) in Y ^a, and the general formula (2-A-20) in is the same meaning as Y ^a and Y ^b in the general formula (2-A). Z ^b of the general formula (3-A-10) in the Z ^a, and the general formula (3-A-20) in is the same meaning as Z ^a and Z ^b in the general formula (3-A).

  The aromatic dicarboxylic acid can also be used as a derivative such as diacid chloride, dimethyl ester, diethyl ester and the like. Further, the aromatic dicarboxylic acid used for the condensation polymerization may contain other aromatic dicarboxylic acids in addition to the above-described aromatic dicarboxylic acids.

The aromatic diol for producing the polyarylate resin R has two phenolic hydroxyl groups. The aromatic diol for producing the polyarylate resin (1-A) is represented, for example, by the following general formula (1-A-11) or general formula (1-A-21). The aromatic diol for producing the polyarylate resin (2-A) is represented by, for example, the following general formula (2-A-11) or general formula (2-A-21). The aromatic diol for producing the polyarylate resin (3-A) is represented, for example, by the following general formula (3-A-11) or general formula (3-A-21). Ka in the general formula (1-A-11) and kb in the general formula (1-A-21) have the same meanings as ka and kb in the general formula (1-A), respectively. Formula (2-A-11) in the Q ^1a and Q ^2a, and Q ^1b and Q ^2b in formula (2-A-21) is, Q ^1a and Q respectively in formula (2-A) ^2a , and synonymous with Q ^1b and Q ^2b . Formula (3-A-11) in the Q ^3a and Q ^4a, and Q ^3b and Q ^4b of the general formula (3-A-21) in the, Q ^3a and Q respectively in formula (3-A) ^4a , and synonymous with Q ^3b and Q ^4b .

  The aromatic diol can be used as a derivative such as diacetate. Further, the aromatic diol used for the condensation polymerization may contain other aromatic diols in addition to the aromatic diols exemplified above.

  Examples of the polyarylate resin (1) include, for example, polyarylate resins represented by the following chemical formulas (R1-1) to (R1-6) (hereinafter, polyarylate resins (R1-1) to (R1-6), respectively) May be described).

  Examples of the polyarylate resin (2) include a polyarylate resin represented by the following chemical formula (R2-1) (hereinafter, may be referred to as a polyarylate resin (R2-1)).

  As the polyarylate resin (3), for example, a polyarylate resin represented by the following chemical formula (R3-1) (hereinafter sometimes referred to as polyarylate resin (R3-1)) may be mentioned.

  Among the polyarylate resins R, polyarylate resins (R1-3), (R1-6) and (R2-1) are preferable from the viewpoint of further improving transferability and filming resistance.

(Acid anhydride)
The charge transport layer contains an acid anhydride represented by the following formula (4), (5), (6) or (7). Hereinafter, the acid anhydrides represented by the general formulas (4) to (7) may be referred to as acid anhydrides (4) to (7), respectively. Further, the acid anhydrides (4) to (7) may be collectively described as an acid anhydride AD. The charge transport layer contains one or more of the acid anhydrides (4) to (7).

In the general formulas (4), (5) and (6), R ¹ , R ² , R ³ and R ⁴ each independently represent a carbon atom of 1 to 6 which may have a substituent. The following alkyl group, an alkoxy group having 1 to 6 carbon atoms which may have a substituent, an aryl group having 6 to 14 carbon atoms which may have a substituent, or a halogen atom is shown. a1 and a2 each independently represent an integer of 0 or more and 3 or less. a3 represents an integer of 0 or more and 2 or less. a4 represents an integer of 0 or more and 4 or less. If a1 is representing two or three, more of R ¹ may be the same or different from each other. When a2 represents 2 or 3, a plurality of R ² may be the same or different. If a3 is 2, two R ³ may be the same or different from each other. If a4 represents an integer of 2 to 4, a plurality of R ⁴ may be the same or different from each other. In the general formula (7), G represents a single bond or an oxygen atom.

  The content of the acid anhydride AD is 0.02 parts by mass or more and 8.00 parts by mass or less based on 100.00 parts by mass of the binder resin. From the viewpoint of further improving the transferability and the filming resistance, the content of the acid anhydride AD is preferably 7.00 parts by mass or less, and more preferably 5.00 parts by mass, based on 100.00 parts by mass of the binder resin. And more preferably 4.00 parts by mass or less.

  The photoreceptor according to the first embodiment contains an acid anhydride AD and the above-described polyarylate resin R in the charge transport layer, and the content of the acid anhydride AD is 0.02 to 100.00 parts by mass of the binder resin. When the amount is from not less than 8.0 parts by mass, transferability is excellent. The reason is presumed as follows.

  When the charge transport layer is formed, in the charge transport layer coating solution, the polyarylate resin R interacts with the acid anhydride AD blended in the above specific range, so that in the charge transport layer formed, The acid anhydride AD tends to be uniformly dispersed. Therefore, in the photoconductor according to the first embodiment, the photosensitive layer tends to have an appropriate electric resistance. As a result, the photoreceptor according to the first embodiment tends to stably hold an electrostatic latent image formed on the photosensitive layer. Therefore, the photoconductor according to the first embodiment is considered to have excellent transferability.

  Further, the photoreceptor according to the first embodiment includes the charge transport layer containing the acid anhydride AD and the above-described polyarylate resin R, and the content of the acid anhydride AD is 0 with respect to 100.00 parts by mass of the binder resin. When the content is from 2.02 parts by mass to 8.00 parts by mass, the filming resistance is excellent. The reason is presumed as follows.

  When forming the charge transport layer, the layer of the charge transport layer formed by the interaction between the polyarylate resin R and the acid anhydride AD blended in the above specific range in the charge transport layer coating solution. Density tends to be high. Thereby, the surface of the photosensitive layer of the photosensitive member according to the first embodiment tends to have a high hardness. As a result, there is a tendency that the adhesion of a component (more specifically, a toner component, paper powder, or the like) that causes filming to the photosensitive layer surface is suppressed. Therefore, the photoconductor according to the first embodiment is considered to have excellent filming resistance.

In the general formulas (4), (5) and (6), the alkyl groups having 1 to 6 carbon atoms represented by R ¹ , R ² , R ³ and R ⁴ have a substituent. May be. Examples of such a substituent include an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, and a halogen atom.

In the general formulas (4), (5) and (6), the alkoxy groups having 1 to 6 carbon atoms represented by R ¹ , R ² , R ³ and R ⁴ have a substituent. May be. Examples of such a substituent include an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, and a halogen atom.

In the general formulas (4), (5) and (6), the aryl groups having 6 to 14 carbon atoms represented by R ¹ , R ² , R ³ and R ⁴ have a substituent. May be. Examples of such a substituent include an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, and a halogen atom.

  In the general formula (4), a1 and a2 preferably represent 0 from the viewpoint of further improving transferability and filming resistance.

  As the acid anhydride (4) represented by the general formula (4), for example, a compound represented by the following chemical formula (A4-1) (hereinafter sometimes referred to as an acid anhydride (A4-1)). Is mentioned.

  In the general formula (5), a3 preferably represents 0 from the viewpoint of further improving transferability and filming resistance.

  As the acid anhydride (5) represented by the general formula (5), for example, a compound represented by the following chemical formula (A5-1) (hereinafter sometimes referred to as acid anhydride (A5-1)) Is mentioned.

In the general formula (6), R ⁴ preferably represents a halogen atom, and more preferably represents a chlorine atom, from the viewpoint of further improving transferability and filming resistance. From the same viewpoint, a4 preferably represents 1 or 2, and more preferably represents 2.

  As the acid anhydride (6) represented by the general formula (6), for example, a compound represented by the following chemical formula (A6-1) (hereinafter sometimes referred to as an acid anhydride (A6-1)) Is mentioned.

  In the general formula (7), G preferably represents an oxygen atom from the viewpoint of further improving transferability and filming resistance.

  As the acid anhydride (7) represented by the general formula (7), for example, a compound represented by the following chemical formula (A7-1) (hereinafter sometimes referred to as acid anhydride (A7-1)) Is mentioned.

  The acid anhydride AD is preferably an acid anhydride (4) or an acid anhydride (5) from the viewpoint of further improving the filming resistance by reducing the scratch depth of the photosensitive layer, and is preferably an acid anhydride (A4). -1) and acid anhydride (A5-1) are more preferred.

(Electron acceptor compound)
The charge transport layer may contain an electron acceptor compound as needed. This tends to improve the hole transporting ability of the hole transporting agent.

  Examples of the electron acceptor compound include quinone compounds, diimide compounds, hydrazone compounds, malononitrile compounds, thiopyran compounds, trinitrothioxanthone compounds, 3,4,5,7-tetranitro-9-fluorenone compounds, Examples include dinitroanthracene compounds, dinitroacridine compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, and dinitroacridine. Examples of the quinone-based compound include a diphenoquinone-based compound, an azoquinone-based compound, an anthraquinone-based compound, a naphthoquinone-based compound, a nitroanthraquinone-based compound, and a dinitroanthraquinone-based compound. One kind of the electron acceptor compound may be used alone, or two or more kinds thereof may be used in combination.

(Additive)
The charge transport layer may contain an additive as needed. Examples of the additives include a deterioration inhibitor (more specifically, an antioxidant, a radical scavenger, a quencher, and an ultraviolet absorber), a softener, a surface modifier, a bulking agent, a thickener, and a dispersion Examples include stabilizers, waxes, donors, surfactants, and leveling agents.

  Examples of the antioxidant include a hindered phenol compound, a hindered amine compound, a thioether compound, and a phosphite compound. Among these antioxidants, hindered phenol compounds and hindered amine compounds are preferred.

[3. Middle layer]
The photoreceptor according to the first embodiment may have an intermediate layer (for example, an undercoat layer). The intermediate layer contains, for example, inorganic particles and a resin used for the intermediate layer (a resin for the intermediate layer). When an intermediate layer is interposed, the flow of current generated when the photosensitive member is exposed can be made smooth, and an increase in electrical resistance can be suppressed, while maintaining an insulating state that can suppress the occurrence of leakage.

  Examples of the inorganic particles include metal particles (more specifically, aluminum, iron, copper, etc.) and metal oxides (more specifically, titanium oxide, alumina, zirconium oxide, tin oxide, zinc oxide, etc.). And particles of a nonmetal oxide (more specifically, silica or the like). One type of these inorganic particles may be used alone, or two or more types may be used in combination. The inorganic particles may be subjected to a surface treatment.

  The resin for the intermediate layer is not particularly limited as long as it can be used as a resin for forming the intermediate layer.

[4. Production method of photoreceptor]
The method for manufacturing the photoconductor according to the first embodiment is not particularly limited as long as the method includes a photosensitive layer forming step. The photosensitive layer forming step includes, for example, a charge generating layer forming step and a charge transporting layer forming step.

  In the charge generation layer forming step, first, a charge generation layer coating solution is prepared. Next, the coating solution for the charge generation layer is applied on the conductive substrate. Next, by drying by an appropriate method, at least a part of the solvent contained in the applied coating solution for a charge generation layer is removed to form a charge generation layer. The coating solution for the charge generation layer contains, for example, a charge generation agent, a base resin, and a solvent. Such a charge generation layer coating solution can be prepared by dissolving or dispersing a charge generation agent and a base resin in a solvent. An additive may be added to the charge generation layer coating solution as needed.

  In the charge transport layer forming step, first, a charge transport layer coating solution is prepared. Next, the charge transport layer coating solution is applied on the charge generation layer. Next, by drying by an appropriate method, at least a part of the solvent contained in the applied coating liquid for a charge transport layer is removed to form a charge transport layer. The coating solution for the charge transport layer contains, for example, a hole transport agent, a polyarylate resin R as a binder resin, an acid anhydride AD, and a solvent. Such a charge transport layer coating solution can be prepared by dissolving or dispersing the hole transport agent, the polyarylate resin R, and the acid anhydride AD in a solvent. If necessary, one or both of the electron acceptor compound and the additive may be added to the charge transport layer coating solution.

  Hereinafter, details of the photosensitive layer forming step will be described. The solvent contained in the coating solution for the charge generation layer and the coating solution for the charge transport layer (hereinafter, these may be collectively referred to as a coating solution) may be used as long as the components contained in the coating solution can be dissolved or dispersed. There is no particular limitation. Examples of the solvent include 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, o-xylene, m-xylene, p-xylene, etc.), halogenated hydrocarbons (more specifically, dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene, etc.), ethers (more Specifically, dimethyl ether, diethyl ether, tetrahydrofuran, 1,4-dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, etc.), ketones (more specifically, acetone, methyl ethyl ketone, cyclohexanone, etc.), esters (more specifically, ,vinegar Ethyl, methyl acetate, etc.), dimethylformamide, dimethyl formamide, and dimethyl sulfoxide and the like. These solvents may be used alone or in combination of two or more. Among these solvents, it is preferable to use a non-halogen solvent.

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

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

  The method for applying the coating liquid is not particularly limited as long as the method can uniformly apply the coating liquid. Examples of the coating method include a dip coating method, a spray coating method, a spin coating method, and a bar coating method.

  The method for removing at least a part of the solvent contained in the coating solution is not particularly limited as long as at least a part of the solvent in the coating solution can be evaporated. Examples of the removing method include heating, decompression, and a combination of heating and decompression. More specifically, a method of performing a heat treatment (hot-air drying) using a high-temperature dryer or a reduced-pressure dryer is exemplified. The heat treatment conditions are, for example, a temperature of 40 ° C. or more and 150 ° C. or less, and a time of 3 minutes or more and 120 minutes or less.

  The method of manufacturing the photoconductor may further include a step of forming an intermediate layer as necessary. For the step of forming the intermediate layer, a known method can be appropriately selected.

  Since the photoreceptor according to the first embodiment described above has excellent transferability and filming resistance, it can be suitably used in various image forming apparatuses.

<Second Embodiment: Image Forming Apparatus>
Hereinafter, an outline of the image forming apparatus according to the second embodiment will be described with reference to FIG. The image forming apparatus 100 includes the image carrier 30, a charging unit 42, an exposure unit 44, a developing unit 46, and a transfer unit 48. The image carrier 30 is the photoconductor according to the above-described first embodiment. The charging section 42 charges the surface of the image carrier 30. The exposure section 44 exposes the charged surface of the image carrier 30 to form an electrostatic latent image on the surface of the image carrier 30. The developing unit 46 develops the electrostatic latent image as a toner image. The transfer unit 48 transfers the toner image from the image carrier 30 to the recording medium P while bringing the surface of the image carrier 30 into contact with the recording medium P (transfer medium). The outline of the image forming apparatus 100 according to the second embodiment has been described above.

  The image forming apparatus 100 according to the second embodiment can suppress occurrence of an image defect. The reason is presumed as follows. The image forming apparatus 100 according to the second embodiment includes the photoconductor according to the first embodiment as the image carrier 30. The photoreceptor according to the first embodiment is excellent in transferability and filming resistance. Therefore, the image forming apparatus 100 according to the second embodiment can suppress an image defect (more specifically, an image defect due to a decrease in transferability, an image defect due to filming, and the like). Hereinafter, as an example of an image defect, an image defect due to a decrease in transferability will be described.

  When the transferability is reduced, the toner that cannot be completely transferred remains on the image carrier 30 after the transfer of the toner image onto the recording medium P. The remaining toner may be transferred to an image formed after the next rotation of the reference rotation of the image carrier 30 (an arbitrary rotation when an image is continuously formed). An image defect in which an image reflecting the image of the reference circumference is formed after the next round is an image defect due to a decrease in transferability.

  With reference to FIG. 5, image defects due to a decrease in transferability will be further described. FIG. 5 is a diagram illustrating an image in which an image defect has occurred due to a decrease in transferability. The image 110 has a region 112, a region 114, and a region 116. The region 112, the region 114, and the region 116 are each a region corresponding to one rotation of the image carrier. The image 118 in the area 112 includes a rectangular solid image (image density 100%). The region 114 and the region 116 are respectively blank images (image density 0%) on the entire design image. Along the direction A in which the recording medium is conveyed (conveying direction A), an image 118 of the area 112 is first formed, then an image of the area 114 is formed, and finally an image of the area 116 is formed. Assuming that the circumference on which the image 118 of the area 112 is formed is set as the reference circumference, the image of the area 114 is an image corresponding to one round next to the reference circumference. Further, the image of the region 116 is an image corresponding to one revolution after the reference revolution.

  In this case, when the transferability decreases, an image reflecting the image 118 is formed in the region 114 and / or the region 116 as an image defect. In FIG. 5, an image 120 reflecting the image 118 is formed in the area 114. Further, an image 122 reflecting the image 118 is formed in the area 116. As described above, image defects due to a decrease in transferability occur in a cycle in units of the circumference of the image carrier. Further, images reflecting the image 118 are easily formed at both ends of the recording medium. This is probably because the pressing force on both ends of the recording medium is relatively strong. Here, the both ends of the recording medium are, for example, both ends (regions 120L and 120R) in the direction B orthogonal to the transport direction A in the region 114 of the recording medium, and both ends in the direction B (region 120R) in the region 116. 122L and the region 122R).

  Hereinafter, returning to FIG. 4, the details of the image forming apparatus 100 will be described. The image forming apparatus 100 is a tandem type color image forming apparatus. Further, the image forming apparatus 100 employs a direct transfer method. Normally, in an image forming apparatus employing the direct transfer method, since the image carrier comes into contact with the recording medium, minute components tend to adhere to the surface of the image carrier, and image defects due to filming are likely to occur. . However, the image forming apparatus 100 as an example of the second embodiment includes the photoconductor according to the first embodiment as the image carrier 30. The photoreceptor according to the first embodiment has excellent filming resistance. Therefore, when the photoconductor according to the first embodiment is provided as the image carrier 30, even in the image forming apparatus 100 employing the direct transfer method, occurrence of image defects due to filming can be suppressed.

  The image forming apparatus 100 includes image forming units 40a, 40b, 40c, and 40d, a transfer belt 50, and a fixing unit 52. Hereinafter, each of the image forming units 40a, 40b, 40c, and 40d will be referred to as an image forming unit 40 unless it is necessary to distinguish them.

  The image forming unit 40 includes the image carrier 30, a charging unit 42, an exposing unit 44, a developing unit 46, and a transfer unit 48. An image carrier 30 is provided at a central position of the image forming unit 40. The image carrier 30 is provided rotatably in the arrow direction (counterclockwise). Around the image carrier 30, a charging unit 42, an exposure unit 44, a developing unit 46, and a transfer unit 48 are provided in this order from the upstream side in the rotation direction of the image carrier 30 with respect to the charging unit 42. . The image forming unit 40 may further include one or both of a cleaning unit (not shown) and a charge removing unit (not shown).

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

  The charging unit 42 is a charging roller. The charging roller charges the surface of the image carrier 30 while contacting the surface of the image carrier 30. Generally, in an image forming apparatus including a charging roller, an image defect is likely to occur. However, the image forming apparatus 100 includes the photoconductor according to the first embodiment as the image carrier 30. The photoreceptor according to the first embodiment is excellent in transferability and filming resistance. Therefore, even in the image forming apparatus 100 including the charging roller as the charging unit 42, occurrence of an image defect is suppressed. As described above, the image forming apparatus 100 as an example of the second embodiment employs the contact charging method. An example of another contact charging type charging unit is a charging brush. The charging unit may be of a non-contact type. Examples of the non-contact type charging unit include a corotron charging unit and a scorotron charging unit.

  The voltage applied by the charging unit 42 is not particularly limited. Examples of the voltage applied by the charging unit 42 include a DC voltage, an AC voltage, and a superimposed voltage (a voltage in which an AC voltage is superimposed on a DC voltage), of which a DC voltage is preferable. DC voltage has the following advantages over AC voltage and superimposed voltage. When the charging unit 42 applies only the DC voltage, the voltage applied to the image carrier 30 is constant, so that the surface of the image carrier 30 is easily charged uniformly to a constant potential. When the charging unit 42 applies only the DC voltage, the wear amount of the photosensitive layer tends to decrease. As a result, a suitable image can be formed.

  The exposure unit 44 exposes the surface of the charged image carrier 30 to light. Thus, an electrostatic latent image is formed on the surface of the image carrier 30. The electrostatic latent image is formed based on the image data input to the image forming apparatus 100.

  The developing unit 46 supplies toner to the surface of the image carrier 30, and develops the electrostatic latent image as a toner image. The developing unit 46 can adopt a method of developing the electrostatic latent image as a toner image while contacting the surface of the image carrier 30 (contact developing method). Usually, in an image forming apparatus employing a contact developing method, an image defect is likely to occur. However, the image forming apparatus 100 includes the photoconductor according to the first embodiment as the image carrier 30. The photoreceptor according to the first embodiment is excellent in transferability and filming resistance. Therefore, even if the image forming apparatus 100 including such a photosensitive member employs the contact developing method, occurrence of image defects is suppressed.

  The developing unit 46 can clean the surface of the image carrier 30. That is, the image forming apparatus 100 can adopt a so-called cleanerless system. In this case, the developing unit 46 can remove the residual components on the surface of the image carrier 30. Generally, in an image forming apparatus provided with a cleaning unit (for example, a cleaning blade), residual components on the surface of the image carrier are scraped off by the cleaning unit. However, in the case of a cleaner-less type image forming apparatus, residual components on the surface of the image carrier are not scraped off. Therefore, in an image forming apparatus adopting the cleanerless system, residual components are likely to remain on the surface of the image carrier, so that an image defect due to filming is likely to occur. However, the image forming apparatus 100 includes, as the image carrier 30, the photoconductor of the first embodiment having excellent filming resistance. Accordingly, in the image forming apparatus 100 including such a photoconductor, even when the cleanerless method is adopted, a residual component, particularly, a minute component (for example, paper dust) of the recording medium P hardly remains on the surface of the photoconductor. As a result, the image forming apparatus 100 can suppress the occurrence of image defects due to filming.

  In order to efficiently clean the surface of the image carrier 30 while the developing unit 46 develops, a contact developing method is adopted, and a peripheral speed (rotational speed) difference between the image carrier 30 and the developing unit 46 is reduced. Preferably, it is provided. In this case, the surface of the image carrier 30 comes into contact with the developing unit 46, and residual components on the surface of the image carrier 30 are removed by friction with the developing unit 46. The peripheral speed of the developing unit 46 is preferably higher than the peripheral speed of the image carrier 30.

  The transfer belt 50 conveys the recording medium P between the image carrier 30 and the transfer unit 48. The transfer belt 50 is an endless belt. The transfer belt 50 is provided so as to be rotatable in the arrow direction (clockwise).

  The transfer unit 48 transfers the toner image developed by the developing unit 46 from the surface of the image carrier 30 to the recording medium P. When the toner image is transferred from the image carrier 30 to the recording medium P, the image carrier 30 is in contact with the recording medium P. The transfer unit 48 includes, for example, a transfer roller.

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

  The example of the image forming apparatus according to the second embodiment has been described above, but the image forming apparatus according to the second embodiment is not limited to the image forming apparatus 100 described above. For example, the above-described image forming apparatus 100 is a tandem type image forming apparatus, but the image forming apparatus according to the second embodiment is not limited to this, and a rotary type or the like may be adopted. Further, the image forming apparatus according to the second embodiment may be a monochrome image forming apparatus. In this case, the image forming apparatus may include, for example, only one image forming unit. Further, the image forming apparatus according to the second embodiment may employ an intermediate transfer method. When the image forming apparatus according to the second embodiment employs the intermediate transfer method, the transfer target corresponds to an intermediate transfer belt.

<Third embodiment: process cartridge>
The process cartridge according to the third embodiment includes the photoconductor according to the first embodiment as an image carrier. Subsequently, an example of the process cartridge according to the third embodiment will be described with reference to FIG.

  The process cartridge according to the third embodiment corresponds to, for example, each of the image forming units 40a to 40d (FIG. 4). These process cartridges include a unitized part. The unitized portion includes the image carrier 30. Further, the unitized portion may include at least one selected from the group consisting of a charging unit 42, an exposing unit 44, a developing unit 46, and a transfer unit 48 in addition to the image carrier 30. The process cartridge may further include one or both of a cleaning unit (not shown) and a charge removing unit (not shown). The process cartridge is designed to be detachable from the image forming apparatus 100, for example. In this case, the process cartridge is easy to handle, and when the sensitivity characteristics and the like of the image carrier 30 deteriorate, the process cartridge including the image carrier 30 can be easily and quickly replaced.

  The process cartridge according to the third embodiment described above includes the photoconductor according to the first embodiment as an image carrier, so that occurrence of an image defect can be suppressed.

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

<Material of photoconductor>
The following hole transport agents, binder resins, and acid anhydrides were prepared as materials for manufacturing the photoconductor.

[Hole transport agent]
The hole transport agent (HTM11) described in the first embodiment was prepared.

[Binder resin]
In addition to the polyarylate resins (R1-1) to (R1-6), (R2-1) and (R3-1) described in the first embodiment, a polyarylate resin (R-10) was prepared. The polyarylate resin (R-10) is represented by the following chemical formula (R-10).

  Hereinafter, a method for synthesizing the polyarylate resins (R1-1) to (R1-6), (R2-1) and (R3-1) will be described.

[Synthesis method of polyarylate resin (R1-1)]
A 1-liter three-necked flask equipped with a thermometer, a three-way cock, and a dropping funnel was used as a reaction vessel. In a reaction vessel, 12.2 g (41.3 mmol) of 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane as an aromatic diol, 0.06 g (0.41 mmol) of t-butylphenol, 3.9 g (98 mmol) of sodium hydroxide and 0.12 g (0.38 mmol) of benzyltributylammonium chloride were charged. Next, the inside of the reaction vessel was replaced with argon. Thereafter, 600 mL of water was further charged into the reaction vessel. The internal temperature of the reaction vessel was maintained at 20 ° C., and the contents of the reaction vessel were stirred for 1 hour. Next, the content of the reaction vessel was cooled, and the internal temperature of the reaction vessel was lowered to 10 ° C. Thus, an alkaline aqueous solution was prepared.

  On the other hand, 4.5 g (16.2 mmol) of 4,4'-biphenyldicarboxylic acid dichloride and 4.1 g (16.2 mmol) of 2,6-naphthalenedicarboxylic acid dichloride as aryloyl halide were dissolved in 300 g of chloroform. Then, a chloroform solution was prepared.

  Next, the temperature of the alkaline aqueous solution was maintained at 10 ° C., and while stirring the contents of the reaction vessel, the chloroform solution was charged into the alkaline aqueous solution to start a polymerization reaction. The polymerization reaction was allowed to proceed for 3 hours while stirring the contents of the reaction vessel and maintaining the internal temperature of the reaction vessel at 13 ± 3 ° C. Thereafter, the upper layer (aqueous layer) was removed using a decant to obtain an organic layer.

  Next, 500 mL of ion-exchanged water was charged into a 2 L three-necked flask, and then the obtained organic layer was charged. Further, 300 g of chloroform and 6 mL of acetic acid were added. The contents of the three-necked flask were stirred at room temperature (25 ° C.) for 30 minutes. Thereafter, the upper layer (aqueous layer) in the contents of the three-necked flask was removed using a decant to obtain an organic layer. The organic layer obtained using 500 mL of ion-exchanged water was washed eight times with a separating funnel. As a result, an organic layer washed with water was obtained.

  Next, the organic layer washed with water was filtered to obtain a filtrate. 1.5 L of methanol was charged into a 3 L Erlenmeyer flask. The obtained filtrate was slowly dropped into the Erlenmeyer flask to obtain a precipitate. The precipitate was separated by filtration. The obtained precipitate was dried under vacuum at a temperature of 70 ° C. for 12 hours. As a result, a polyarylate resin (R1-1) having a viscosity average molecular weight of 46,000 was obtained.

[Method of synthesizing polyarylate resins (R1-2) to (R1-6), (R2-1) and (R3-1)]
Except for the following changes, the polyarylate resins (R1-2) to (R1-6), (R2-1), and (R3) were respectively similar to the polyarylate resin (R1-1). -1) was synthesized. The viscosity average molecular weights of the polyarylate resins (R1-2) to (R1-6), (R2-1) and (R3-1) are 46,500, 48,000, 45,000, 46,500, respectively. , 49,000, 51,000 and 52,000.

(change point)
1,1-Bis (4-hydroxy-3-methylphenyl) cyclohexane is an aromatic starting material for polyarylate resins (R1-2) to (R1-6), (R2-1) and (R3-1). Changed to diol. 4,4'-biphenyldicarboxylic acid dichloride and 2,6-naphthalenedicarboxylic acid dichloride are starting materials for polyarylate resins (R1-2) to (R1-6), (R2-1) and (R3-1). Changed to aryloyl halide. The total amount of the aromatic diol in the synthesis of each of the polyarylate resins (R1-2) to (R1-6), (R2-1) and (R3-1) is determined by the polyarylate resin (R1-1) It was the same as the total amount of the aromatic diol in the synthesis of. The total amount of the aryloyl halide in the synthesis of each of the polyarylate resins (R1-2) to (R1-6), (R2-1) and (R3-1) is determined by the synthesis of the polyarylate resin (R1-1). Was the same as the total amount of aryloyl halide.

[Acid anhydride]
An acid anhydride (A10-1) was prepared in addition to the acid anhydrides (A4-1), (A5-1), (A6-1) and (A7-1) described in the first embodiment. The acid anhydride (A10-1) is an acid anhydride represented by the following chemical formula (A10-1).

<Manufacture of photoconductor>
[Photoconductor (A-1)]
Hereinafter, a method for manufacturing the photoconductor (A-1) according to the first embodiment will be described.

(Formation of intermediate layer)
First, surface-treated titanium oxide ("Prototype SMT-A" manufactured by Teica Co., Ltd., average primary particle size: 10 nm) was prepared. Specifically, a titanium oxide surface-treated with alumina and silica, and a surface-treated titanium oxide surface-treated with methyl hydrogen polysiloxane while wet-dispersing the surface-treated titanium oxide was prepared. The surface-treated titanium oxide (2 parts by mass) and the polyamide resin Amilan (registered trademark) (“CM8000” manufactured by Toray Industries, Inc.) (1 part by mass) were added to a solvent. Amilan is a quaternary polyamide resin of polyamide 6, polyamide 12, polyamide 66, and polyamide 610. As the solvent, a solvent containing methanol (10 parts by mass), butanol (1 part by mass), and toluene (1 part by mass) was used. These were mixed for 5 hours using a bead mill, and the materials were dispersed in a solvent. This dispersion was filtered using a filter having a mesh size of 5 μm. Thus, a coating solution for an intermediate layer was prepared.

  The obtained coating solution for an intermediate layer was applied to the surface of an aluminum drum-shaped support (diameter 30 mm, total length 246 mm) as a conductive substrate by dip coating. Subsequently, the applied coating liquid for an intermediate layer was dried at 130 ° C. for 30 minutes to form an intermediate layer (2.0 μm thick) on a conductive substrate (drum-shaped support).

(Formation of charge generation layer)
Y-type titanyl phthalocyanine (1.5 parts by mass) and a polyvinyl acetal resin (“S-LEC BX-5” manufactured by Sekisui Chemical Co., Ltd.) (1 part by mass) as a base resin were added to a solvent. As the solvent, a solvent containing propylene glycol monomethyl ether (40 parts by mass) and tetrahydrofuran (40 parts by mass) was used. These were mixed for 2 hours using a bead mill, and the materials were dispersed in a solvent. This dispersion was filtered using a filter having a mesh size of 3 μm. Thus, a coating solution for the charge generation layer was prepared. The obtained coating solution for a charge generation layer was applied on the intermediate layer formed as described above by using a dip coating method, and dried at 50 ° C. for 5 minutes. Thus, a charge generation layer (thickness: 0.3 μm) was formed on the intermediate layer.

(Formation of charge transport layer)
75.00 parts by mass of a hole transporting agent (HTM11), 0.50 parts by mass of a hindered phenolic antioxidant (“Irganox (registered trademark) 1010” manufactured by BASF) as an additive, and an acid anhydride (A4-1) 1.00 parts by mass and 100.00 parts by mass of a polyarylate resin (R1-1) as a binder resin were added to the solvent. As the solvent, a solvent obtained by mixing 560.00 parts by mass of tetrahydrofuran and 140.00 parts by mass of toluene was used. These materials were dispersed in a solvent for 2 minutes using an ultrasonic disperser to prepare a charge transport layer coating solution.

  Next, the charge transport layer coating solution was applied on the charge generation layer by the same operation as the above-described charge generation layer coating solution. Thereafter, the resultant was dried at 120 ° C. for 40 minutes to form a charge transport layer (film thickness: 20 μm) on the charge generation layer, thereby obtaining a photoreceptor (A-1). The obtained photoreceptor (A-1) was visually observed, and it was confirmed that the surface of the charge transport layer was not crystallized.

[Photoconductors (A-2) to (A-13) and Photoconductors (B-1) to (B-5)]
The photoconductors (A-2) to (A-13) and the photoconductors (B-1) to (B-5) were respectively processed in the same manner as the photoconductor (A-1) except for the following changes. Manufactured. The obtained photoconductors (A-2) to (A-13) and photoconductors (B-1) to (B-5) were each visually observed. Of these, regarding the photoconductors (B-3) and (B-4), the surface of the charge transport layer was crystallized. As for the other photoconductors, the surface of the charge transport layer was not crystallized.

(change point)
The polyarylate resin (R1-1) as a binder resin used in the production of the photoconductor (A-1) was changed to a polyarylate resin shown in Table 1. The acid anhydride (A4-1) and the content thereof used in the production of the photoreceptor (A-1) were changed to the acid anhydride and the content thereof shown in Table 1. In addition, A4-1, A5-1, A6-1, A7-1 and A10-1 of "kind" of the column "acid anhydride" of Table 1 are acid anhydride (A4-1) and (A5- 1), (A6-1), (A7-1) and (A10-1). The "content" in the column "acid anhydride" in Table 1 is the number of parts by mass based on 100.00 parts by mass of the polyarylate resin used.

<Method of measuring physical properties of photosensitive layer>
[Measurement of elastic power]
For each of the obtained photoconductors (A-1) to (A-13) and photoconductors (B-1) to (B-5), the elastic power of the photosensitive layer was measured. The elastic work rate of the photosensitive layer was measured using a micro hardness tester (“H-100” manufactured by Fisher Instruments Co., Ltd.) equipped with a diamond indenter in an environment of a temperature of 23 ° C. and a humidity of 50% RH. B and step C were measured. In step A, a load is applied to the photosensitive layer using a diamond indenter over 30 seconds so that the maximum load becomes 9.8 mN, and the maximum deformation work (EW ₁ : plastic deformation) of the photosensitive layer when the load is applied Work + elastic deformation work). In Step B, the load applied to the photosensitive layer is removed by moving the diamond indenter away from the photosensitive layer over 30 seconds, and the amount of restoration (EW ₂ : work of elastic deformation) of the photosensitive layer when the load is removed is measured. did. In step C, from the measured maximum deformation work amount (EW ₁ ) of the photosensitive layer and the restoration amount (EW ₂ ) of the photosensitive layer, according to the equation “elastic power (%) = (100 × EW ₂ ) / EW ₁ ”. The elastic power of the photosensitive layer was determined. Table 2 shows the results. As the elastic power of the photosensitive layer increases, the occurrence of filming tends to be suppressed. The measurement conditions of the elastic power were as follows.

(Measurement conditions of elastic power)
Measurement mode: dF / dt = const
Maximum load: 9.8mN
Loading time: 30 seconds Unloading time: 30 seconds Creep time: 5 seconds

[Measurement of scratch depth]
The scratch depth of the photosensitive layer was measured for each of the obtained photoconductors (A-1) to (A-13) and photoconductors (B-1) to (B-5). The scratch depth was determined using a scratching device 200 (see FIG. 6) according to JIS K5600-5-5 (Japanese Industrial Standards K5600: General Test Method for Paints, Part 5: Mechanical Properties of Coating Film, Section 5: Scratch Hardness). (Load needle method)).

  Hereinafter, the scratching device 200 specified in JIS K5600-5-5 will be described with reference to FIG. FIG. 6 is a diagram illustrating an example of the configuration of the scratching device 200. The scratching device 200 includes a fixing base 201, a fixing tool 202, a scratching needle 203, a support arm 204, two shaft supports 205, a base 206, two rails 207, a weight plate 208, , A constant speed motor (not shown). A weight 209 is placed on the weight pan 208.

  In FIG. 6, the X-axis direction and the Y-axis direction are horizontal directions, and the Z-axis direction is a vertical direction. The X-axis direction indicates the longitudinal direction of the fixed base 201. The Y-axis direction indicates a direction orthogonal to the X-axis direction in a plane parallel to the upper surface 201a (mounting surface) of the fixed base 201. In addition, the X-axis direction, the Y-axis direction, and the Z-axis direction in FIGS.

  The fixing table 201 corresponds to a test plate fixing table in JIS K5600-5-5. The fixed base 201 includes an upper surface 201a, one end 201b, and another end 201c. The upper surface 201a of the fixed base 201 is a horizontal plane. One end 201b faces the two shaft support portions 205.

  The fixing tool 202 is provided on the upper surface 201a of the fixing base 201 on the side of the other end 201c. The fixture 202 fixes the measurement target (photoconductor 1) on the upper surface 201 a of the fixing base 201.

  The scratching needle 203 has a tip 203b (see FIG. 7). The structure of the tip 203b is a hemisphere with a diameter of 1 mm. The material of the tip 203b is sapphire.

  The support arm 204 supports the scratching needle 203. The support arm 204 rotates about the support shaft 204 a in a direction in which the scratching needle 203 approaches and separates from the photoconductor 1.

  The two shaft support portions 205 rotatably support the support arm portion 204.

  The base 206 has an upper surface 206a. Two shaft support portions 205 are provided on one end side of the upper surface 206a.

  The two rail portions 207 are provided on the other end side of the upper surface 206a. The two rail portions 207 are provided so as to face each other in parallel. Each of the two rail portions 207 is provided in parallel with the longitudinal direction (X-axis direction) of the fixed base 201. A fixed base 201 is attached between the two rails 207. Along the rail portion 207, the fixed base 201 is horizontally movable in the longitudinal direction (X-axis direction) of the fixed base 201.

  The weight pan 208 is provided on the scratching needle 203 via the support arm 204. A weight 209 is placed on the weight pan 208.

  The constant speed motor moves the fixed base 201 along the rail 207 in the X-axis direction.

  Hereinafter, a method of measuring the scratch depth will be described. The method of measuring the scratch depth includes the following first step, second step, third step, and fourth step. As the scratching device 200, a surface property measuring device (“HEIDON TYPE14” manufactured by Shinto Kagaku Co., Ltd.) was used. The measurement of the scratch depth was performed in an environment at a temperature of 23 ° C. and a humidity of 50% RH. The shape of the photoconductor 1 was a drum shape (cylindrical shape).

(First step)
In the first step, the photoconductor 1 was fixed to the upper surface 201a of the fixing base 201 such that the longitudinal direction of the photoconductor 1 was parallel to the longitudinal direction of the fixing base 201. At this time, the photoconductor 1 was mounted such that the direction of the center axis L ₂ (rotation axis) of the photoconductor 1 was parallel to the longitudinal direction of the fixed base 201.

(Second step)
In the second step, the scratching needle 203 was brought into perpendicular contact with the surface 3c of the photosensitive layer 3. Referring to FIGS. 7 and 8, in addition to FIG. 6, a method of vertically contacting the scratching needle 203 with the surface 3c of the photosensitive layer 3 of the drum-shaped photosensitive member 1 will be described.

  FIG. 7 is a cross-sectional view taken along the line IV-IV in FIG. 6, and is a cross-sectional view when the scratching needle 203 is brought into contact with the photoconductor 1. FIG. 8 is a side view of the fixing table 201, the scratching needle 203, and the photoconductor 1 shown in FIG.

As an extension of the center axis A ₁ of the scratching needle 203 is perpendicular to the upper surface 201a of the fixing base 201, it is brought close to scratch needle 203 to the photosensitive member 1. Next, on the surface 3 c of the photosensitive layer 3 of the photosensitive member 1, the tip 203 _b of the scratching needle 203 contacts the point (contact point P ₂ ) farthest in the vertical direction (Z-axis direction) from the upper surface 201 a of the fixing base 201. I let it. Thus, the center axis A ₁ of the scratching needle 203 to be perpendicular to the tangent A _2, the tip 203b of the scratching needle 203 is in contact with the photosensitive member 1. At this time, a line segment connecting the contact point P ₂ of the contact P ₁ and the distal end 203b of the upper surface 201a has been perpendicular to the center axis L ₂ of the photosensitive member 1. Note that the tangent line A ₂ is a tangent line at the contact point P ₂ of the peripheral circle constituting the photosensitive member 1 of a cross section perpendicular to the central axis L _2.

(Third step)
Next, the third step will be described with reference to FIGS. In the third step, a load W of 10 g was applied to the photosensitive layer 3 from the scratching needle 203 in a state where the scratching needle 203 was vertically contacted with the surface 3c of the photosensitive layer 3. Specifically, 10 g of a weight 209 was placed on the weight dish 208. In this state, the fixed base 201 was moved. Specifically, the fixed speed motor was driven to move the fixed base 201 horizontally in the X-axis direction along the rail portion 207. That is, one end 201b of the fixed base 201, is moved from the first position N ₁ to the second position N _2. Incidentally, the second position N ₂ was located on the downstream side with respect to the first position N _1. The downstream side is a side where the fixed base 201 is located in a direction in which the fixed base 201 is separated from the two shaft support portions 205 in the longitudinal direction of the fixed base 201. With the movement of the fixed base 201 in the longitudinal direction, the photoconductor 1 also moved horizontally in the longitudinal direction of the fixed base 201. The moving speed of the fixed base 201 and the photosensitive member 1 was 30 mm / min. Further, the moving distance between the fixed base 201 and the photoconductor 1 was 30 mm. The movement distance of the fixed base 201 and the photosensitive member 1, corresponding to the first position N ₁ and distance D _1-2 between the second position N _2. As a result of the movement of the fixed base 201 and the photosensitive member 1, a scratch S was formed on the surface 3 c of the photosensitive layer 3 of the photosensitive member 1 by the scratching needle 203.

Next, the scratch S will be described with reference to FIG. 9 in addition to FIGS. FIG. 9 shows a scratch S formed on the surface 3 c of the photosensitive layer 3. Scratches S, to the upper surface 201a and tangential A ₂ of the fixing table 201, are respectively vertically formed. Moreover, it scratches S was formed so as to pass through the line L ₃ shown in FIG. The line L ₃ is a plurality of lines consisting of the contact point P _2. Line L _3, relative to the center axis L ₂ of the upper surface 201a and the photosensitive member 1 of the fixing base 201, were respectively parallel. The line L ₃ was perpendicular to the central axis A ₁ of the scratching needle 203.

(4th step)
In the fourth step, the scratch depth, which is the maximum value of the depth Ds of the scratch S, was measured. Specifically, the photoconductor 1 was removed from the fixed base 201. Using a three-dimensional interference microscope ("WYKO NT-1100" manufactured by Bruker), the scratches S formed on the photosensitive layer 3 of the photoreceptor 1 are observed at a magnification of 5 times, and the depth Ds of the scratches S is measured. did. The depth Ds of the scratches S was from tangent A _2, the distance to the valley of the scratches S. The maximum value among the depths Ds of the scratches S was defined as the scratch depth. Table 2 shows the results. The smaller the scratch depth of the photosensitive layer 3 is, the more the occurrence of filming tends to be suppressed.

<Evaluation method>
[Evaluation of filming resistance]
Each of the obtained photoconductors (A-1) to (A-13) and photoconductors (B-1) to (B-5) was evaluated for the following filming resistance.

  A color printer (“ECOSYS (registered trademark) FS-C5400DN” manufactured by Kyocera Document Solutions Inc.) was used as an evaluation machine. This evaluation machine was a modified machine modified to a cleanerless system. That is, in this evaluation machine, the cleaning blade was removed and the developing unit was modified to clean the surface of the photoconductor. This evaluation machine employed a direct transfer system. This evaluation machine was provided with a charging roller as a charging unit. In addition, “Kyocera Document Solutions brand paper VM-A4 (A4 size)” sold by Kyocera Document Solutions Co., Ltd. was used as evaluation paper. "TK-131" manufactured by Kyocera Document Solutions, Inc. was used as a toner for evaluation.

  The photoreceptor was mounted on an evaluation machine, and the charging potential was set to -600V. Next, an image I (a pattern image with a printing rate of 1%) was printed at intervals of 16 seconds on 2,000 sheets of paper in an environment of a temperature of 32 ° C. and a humidity of 85% RH. Next, the image I was printed at intervals of 16 seconds on 2,000 sheets of paper in an environment of a temperature of 10 ° C. and a humidity of 15% RH. After the printing is completed, the evaluation machine equipped with the photoconductor is left in an environment of a temperature of 10 ° C. and a humidity of 15% RH for 2 hours, and then a solid image (image density 100%) is printed on one sheet of paper. Was used as an evaluation image (E-1). About the obtained evaluation image (E-1), the presence or absence of white spots was visually checked, and evaluated according to the following criteria. Table 2 shows the results. When filming occurs on the surface of the photoreceptor, the formed image tends to have white spots.

(Evaluation criteria for filming resistance)
A (particularly good): No white spots were observed in the evaluation image (E-1).
B (good): White spots were slightly observed in the evaluation image (E-1), but there were no problems in practical use.
C (poor): White spots were clearly confirmed in the evaluation image (E-1).

[Evaluation of transferability]
The transferability shown below was evaluated for each of the obtained photoconductors (A-1) to (A-13) and photoconductors (B-1) to (B-5). The same evaluation machine, paper and toner as those used in the evaluation of filming resistance were used.

  The photoconductor was mounted on an evaluation machine, the charging potential was set to -600 V, and the current applied to the photoconductor by the transfer roller was set to +25 μA. Next, a printing pattern (printing rate: 4%) was printed at intervals of 16 seconds on 2,000 sheets of paper in an environment of a temperature of 32 ° C. and a humidity of 85% RH to perform a printing test. Immediately after this printing test, one evaluation image (E-2) was printed.

  The design image of the evaluation image (E-2) will be described with reference to FIG. FIG. 10 is a diagram illustrating a design image of the evaluation image (E-2). The design image 150 includes a region 152, a region 154, and a region 156. The area 152 is an area corresponding to one rotation of the image carrier. The image 158 in the area 152 includes a rectangular solid image (image density 100%). Each of the area 154 and the area 156 is an area corresponding to one rotation of the image carrier, and each is an entire blank image (image density of 0%). An image 158 in the area 152 is formed first along the direction A in which the sheet is transported (transport direction A), then an image in the area 154 is formed, and finally an image in the area 156 is formed. When the circumference on which the image 158 of the area 152 is formed is set as a reference circumference, the image of the area 154 is an image corresponding to one next round of the reference circumference. The image of the area 156 is an image corresponding to one revolution after the reference revolution. The region 160 is a region corresponding to the image 158 in the region 154. The region 162 is a region corresponding to the image 158 in the region 156.

  The printed evaluation image (E-2) was visually observed, and the presence or absence of an image reflecting the image 158 was confirmed in the region 160 and the region 162, and evaluated based on the following criteria. Table 2 shows the results.

(Evaluation criteria for transferability)
A (especially good): No image reflecting the image 158 was found in the region 160 and the region 162.
B (good): An image reflecting the image 158 was slightly observed at both ends in the direction B orthogonal to the direction A in the region 160, but no image reflecting the image 158 was found in the region 162.
C (defective): An image reflecting the image 158 was clearly confirmed at both ends in the direction B orthogonal to the direction A in the region 160.

  As shown in Table 1, the photoreceptors (A-1) to (A-13) are polyarylate resins having a repeating unit included in the general formula (1), the general formula (2) or the general formula (3). Any one of (R1-1) to (R1-6), (R2-1) and (R3-1) was contained in the charge transport layer. The photoreceptors (A-1) to (A-13) are acid anhydrides (A4-1) included in the general formulas (4), (5), (6) and (7). , (A5-1), (A6-1) and (A7-1) were contained in the charge transport layer. Photoconductors (A-1) to (A-13) had an acid anhydride content of 0.03 to 7.50 parts by mass based on 100.00 parts by mass of the binder resin. As shown in Table 2, the evaluation results of the photoconductors (A-1) to (A-13) were A (especially good) or B (good). For the photoreceptors (A-1) to (A-13), the evaluation results of the transferability were A (particularly good) or B (good).

  As shown in Table 1, the photoreceptor (B-1) contained a polyarylate resin (R-10) not included in the general formulas (1), (2) and (3) in the charge transport layer. Was. Photoconductor (B-2) had an acid anhydride content of less than 0.02 parts by mass with respect to 100.00 parts by mass of the binder resin. In the photoconductors (B-3) and (B-4), the content of the acid anhydride exceeded 8.00 parts by mass with respect to 100.00 parts by mass of the binder resin. The photoconductor (B-5) contains an acid anhydride (A10-1) not included in the general formulas (4), (5), (6) and (7) in the charge transport layer. I was As shown in Table 2, the photoconductors (B-1) to (B-5) had a filming resistance evaluation result of C (poor). For the photoconductors (B-2) to (B-5), the evaluation result of the transferability was C (poor).

  As is clear from the above results, the photoconductors (A-1) to (A-13) were more excellent in filming resistance than the photoconductors (B-1) to (B-5). Photoconductors (A-1) to (A-13) were superior in transferability to photoconductors (B-2) to (B-5).

  The electrophotographic photosensitive member according to the present invention can be used for an image forming apparatus such as a multifunction peripheral.

REFERENCE SIGNS LIST 1 electrophotographic photoreceptor 2 conductive substrate 3 photosensitive layer 3a charge generation layer 3b charge transport layer 4 intermediate layer

Claims (17)

An electrophotographic photosensitive member comprising a conductive substrate and a photosensitive layer,
The photosensitive layer has a charge generation layer and a charge transport layer,
The charge generation layer contains a charge generation agent,
The charge transport layer includes a hole transport agent, a binder resin, and a carboxylic anhydride,
The binder resin includes a polyarylate resin,
The polyarylate resin has a repeating unit represented by the following general formula (1), general formula (2) or general formula (3),
The carboxylic anhydride is a compound represented by the following general formula (4), general formula (5), general formula (6) or general formula (7),
The electrophotographic photoreceptor, wherein the content of the carboxylic anhydride is 0.02 to 8.00 parts by mass based on 100.00 parts by mass of the binder resin.

(In the general formula (1), k represents 3 .
In the general formulas (1), (2) and (3),
X, Y and Z are each independently a divalent group represented by the following chemical formula (1A), Structural Formula (1C), chemical formula (1F) or formula (1G),
Q ¹ and Q ² represent a hydrogen atom,
Q ³ and Q ⁴ represent a methyl group . )

(In the general formulas (4), (5) and (6),
R ¹ , R ² , R ³ and R ⁴ each independently represent an alkyl group having 1 to 6 carbon atoms which may have a substituent or 1 to 6 carbon atoms which may have a substituent. Represents the following alkoxy group, an aryl group having 6 to 14 carbon atoms that may have a substituent, or a halogen atom,
a1 and a2 each independently represent an integer of 0 to 3,
a3 represents an integer of 0 or more and 2 or less,
a4 represents an integer of 0 or more and 4 or less,
When a1 represents 2 or 3, a plurality of R ¹ may be the same or different from each other;
If a2 is representing two or 3, plural R ^{2 s} may be the same or different from each other,
If a3 is 2, two R ³ may be the same or different from each other,
When a4 represents an integer of 2 to 4, a plurality of R ⁴ may be the same or different from each other,
In the general formula (7), G represents a single bond or an oxygen atom. )   The electrophotographic photosensitive member according to claim 1, wherein the elastic layer has an elastic power of 45.0% or more.   The electrophotographic photosensitive member according to claim 1, wherein a scratch depth of the photosensitive layer is 1.00 μm or less. The electrophotographic photoreceptor according to any one of claims 1 to 3, wherein the hole transporting agent includes a compound represented by the following general formula (11).

(In the general formula (11),
Q ⁸ , Q ¹⁰ , Q ¹¹ , Q ¹² , Q ¹³ and Q ¹⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or phenyl. Represents a group,
Q ⁹ and Q ¹⁵ each independently represent an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group;
b represents an integer of 0 to 5;
c represents an integer of 0 to 4;
When b represents an integer of 2 to 5, a plurality of Q ⁹ bonded to the same phenyl group may be the same or different from each other;
When c represents an integer of 2 or more and 4 or less, a plurality of Q ¹⁵ bonded to the same phenylene group may be the same or different from each other;
m represents 0 or 1. )   The electrophotographic photoreceptor according to claim 1, wherein the polyarylate resin has a repeating unit represented by the general formula (1) or (2). The polyarylate resin is selected from the repeating units represented by the following chemical formulas (1-1), (1-2) and (1-3) as the repeating units represented by the general formula (1). The electrophotographic photoreceptor according to claim 5, wherein the electrophotographic photoreceptor has at least one kind.

The polyarylate resin includes, as a repeating unit represented by the general formula (2), a repeating unit represented by the following chemical formula (2-1) and a repeating unit represented by the following chemical formula (2-2). The electrophotographic photoreceptor according to claim 5, which has:

The polyarylate resin includes, as a repeating unit represented by the general formula (3), a repeating unit represented by the following chemical formula (3-1) and a repeating unit represented by the following chemical formula (3-2). The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor has:

The electrophotographic photoreceptor according to any one of claims 1 to 8 , wherein the carboxylic anhydride is a compound represented by the general formula (4) or the general formula (5). The carboxylic anhydride is a compound represented by the general formula (6),
In the general formula (6), R ⁴ represents a halogen atom;
The electrophotographic photoreceptor according to any one of claims 1 to 8 , wherein a4 represents 1 or 2. The carboxylic anhydride is a compound represented by the general formula (7),
The electrophotographic photoreceptor according to any one of claims 1 to 8 , wherein in the general formula (7), G represents an oxygen atom. The carboxylic acid anhydride is a compound represented by the following chemical formula (A4-1), the formula (A5-1), the formula (A6-1), or formula (A7-1), according to claim 1-8 The electrophotographic photosensitive member according to claim 1.

Comprising an electrophotographic photosensitive member according to any one of claim 1 to 12 the process cartridge. An image carrier;
A charging unit for charging the surface of the image carrier,
Exposure unit that exposes the charged surface of the image carrier to form an electrostatic latent image on the surface of the image carrier,
A developing unit that develops the electrostatic latent image as a toner image;
A transfer unit for transferring the toner image from the image carrier to the transfer target, an image forming apparatus comprising:
The image bearing member is the electrophotographic photosensitive member according to any one of claims 1 to 12 ,
The image forming apparatus, wherein the transfer unit transfers the toner image from the image carrier to the transfer body while bringing the surface of the image carrier into contact with the transfer body. The image forming apparatus according to claim 14 , wherein the transfer target is a recording medium. The developing unit cleans the surface of the image bearing member, an image forming apparatus according to claim 14 or 15. The image forming apparatus according to any one of claims 14 to 16 , wherein the charging unit is a charging roller.

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