JP2018189704A - Electrophotographic photoreceptor, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that is excellent in transferability and filming resistance.SOLUTION: An electrophotographic photoreceptor 1 comprises a conductive substrate 2 and a photosensitive layer 3. The photosensitive layer 3 has a charge generating layer 3a and a charge transport layer 3b. The charge generating layer 3a contains a charge generating agent. The charge transport layer 3b contains a hole transport agent, a binder resin, and carboxylic acid anhydride having a specific structure. The binder resin contains a polyarylate resin having a specific structure. The content of the carboxylic acid anhydride 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.SELECTED DRAWING: Figure 1

Description

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

  The electrophotographic photosensitive member is used as an image carrier in an electrophotographic image forming apparatus (for example, a printer and a multifunction machine). The electrophotographic photoreceptor includes a photosensitive layer. Examples of the electrophotographic photosensitive member include a single layer type electrophotographic photosensitive member and a laminated type electrophotographic photosensitive member. The single-layer type electrophotographic photosensitive member includes a photosensitive layer having a charge generation function and a charge transport function. The multilayer electrophotographic photosensitive member 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 photoreceptor containing a polyarylate resin represented by the following chemical formula (R-A).

Japanese Patent Laid-Open No. 10-288845

  However, the electrophotographic photosensitive member described in Patent Document 1 has insufficient toner image transferability (hereinafter sometimes referred to as transferability) and filming resistance.

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

  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 includes a charge generation agent. The charge transport layer includes a hole transport agent, a binder resin, and a carboxylic acid 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 acid 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 parts by mass or more and 8.00 parts by mass or less with respect to 100.00 parts by mass of the binder resin.

In the general formula (1), k represents 2 or 3. In the general formula (1), general formula (2), and general formula (3), X, Y, and Z are each independently the following chemical formula (1A), chemical formula (1B), chemical formula (1C), chemical formula (1D ), A chemical formula (1E), a chemical formula (1F), or a 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 formula (4), general formula (5) and general formula (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 alkyl, 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. When a1 represents 2 or 3, the plurality of R ¹ may be the same as or different from each other. When a2 represents 2 or 3, the plurality of R ² may be the same as or different from each other. When a3 represents 2, two R ^{3 s} may be the same as or different from each other. When a4 represents an integer of 2 or more and 4 or less, the plurality of R ⁴ may be the same as or different from each other. In the general formula (7), G represents a single bond or an oxygen atom.

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

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

  The electrophotographic photosensitive member of the present invention can improve transferability and filming resistance. In addition, the process cartridge and the image forming apparatus of the present invention can suppress the occurrence of image defects.

It is a fragmentary sectional view showing an example of the structure of the electrophotographic photosensitive member according to the first embodiment of the present invention. It is a fragmentary sectional view showing an example of the structure of the electrophotographic photosensitive member according to the first embodiment of the present invention. It is a fragmentary sectional view showing an example of the structure of the electrophotographic photosensitive member according to the first embodiment of the present invention. It is a figure which shows an example of the image forming apparatus which concerns on 2nd embodiment of this invention. It is a figure which shows the image in which the image defect generate | occur | produced. It is a figure which shows an example of a structure of a scratching device. It is sectional drawing in the IV-IV line of FIG. FIG. 7 is a side view of the fixing base, the scratching needle, and the electrophotographic photosensitive member shown in FIG. 6. It is a figure which shows the scratch formed in the surface of the photosensitive layer. It is a figure which shows the design image of the evaluation image used for transferability evaluation.

  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 object of the present invention. In addition, although description may be abbreviate | omitted suitably about the location where description overlaps, the summary of invention is not limited. In the present specification, a compound and its derivatives may be generically named by adding “system” after the compound name. When the name of a polymer is expressed by adding “system” after the compound name, it means that the repeating unit of the polymer is derived from the compound or a derivative thereof.

  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.

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

  The alkoxy group having 1 to 6 carbon atoms is linear or branched and unsubstituted. Examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an s-butoxy group, a t-butoxy group, a pentyloxy group, an iso group. 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, for example, an unsubstituted aromatic monocyclic hydrocarbon group having 6 to 14 carbon atoms, and an unsubstituted aromatic condensed bicycle having 6 to 14 carbon atoms. Examples thereof include a hydrocarbon group and an unsubstituted aromatic condensed 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.

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

  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 photoreceptor (hereinafter sometimes referred to as a photoreceptor) according to the first embodiment of the present invention will be described. 1, 2, and 3 are partial cross-sectional views illustrating the structure of a photoreceptor 1 that is an example of the first embodiment. As shown in FIG. 1, the photoreceptor 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 charge transport layer 3b is generally thicker than 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 abrasion resistance of the photoreceptor 1, as shown in FIG. 1, a charge generation layer 3a is provided on the conductive substrate 2, and a charge transport layer 3b is provided on the charge generation layer 3a. It is preferable.

  As shown in FIG. 3, the photoreceptor 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 Step A, Step B, and Step 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. The In step A, a diamond indenter is used to apply a load to the photosensitive layer 3 over 30 seconds so that the maximum load is 9.8 mN. When the load is applied, the maximum deformation work (EW ₁ : Work of plastic deformation + work of elastic deformation) is measured. In Step B, the diamond indenter is separated from the photosensitive layer 3 over 30 seconds, the load applied to the photosensitive layer 3 is removed, and the restoration amount of the photosensitive layer 3 when the load is removed (EW ₂ : work of elastic deformation). ). In Step C, from the measured maximum deformation work (EW ₁ ) of the photosensitive layer 3 and the restoration amount (EW ₂ ) of the photosensitive layer 3, the formula “elastic work rate (%) = (100 × EW ₂ ) / EW ₁ ”To obtain the elastic power of the photosensitive layer 3.

  The outline of the method for measuring the elastic power of the photosensitive layer 3 has been described above. A 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 polyarylate resin described later and the type and content of carboxylic anhydride described below.

  From the viewpoint of further improving the filming resistance, 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. preferable.

  The scratch depth of the photosensitive layer 3 is measured by performing the following first step, second step, third step, and fourth step using a scratch device defined in JIS K5600-5-5. The 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 photosensitive member 1 is fixed to the upper surface of the fixing base so that the longitudinal direction of the photosensitive member 1 is parallel to the longitudinal direction of the fixing base. In the second step, the scratch 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 from the scratching needle to the photosensitive layer 3, the fixed base and the photosensitive member 1 fixed on the upper surface of the fixed base are moved by 30 mm at a speed of 30 mm / min in the longitudinal direction of the fixed base. Let By this third step, scratches are formed on the surface of the photosensitive layer 3. In the fourth step, the scratch depth that is 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 for 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 polyarylate resin described later and the type and content of carboxylic anhydride described below.

  The thicknesses of the charge generation layer 3a and the charge transport layer 3b are not particularly limited as long as the functions as the respective layers can be sufficiently expressed. 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, and more preferably 5 μm or more and 50 μm or less. The structure of the photoreceptor 1 has been described above with reference to FIGS.

  Hereinafter, the elements (conductive substrate, photosensitive layer, and intermediate layer) of the photoreceptor according to this embodiment will be described. Further, a method for producing a photoreceptor will be described.

[1. Conductive substrate]
The conductive substrate is not particularly limited as long as it can be used as the conductive substrate of the photoreceptor. As the conductive substrate, a conductive substrate formed of a material having at least a surface portion having conductivity can be used. As an example of the conductive substrate, a conductive substrate made of a conductive material (conductive material) can be given. Another example of a conductive substrate is a conductive substrate coated with a conductive material. Examples of the conductive material include aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, and indium. Among these conductive materials, one kind may be used alone, or two or more kinds may be used in combination. Examples of combinations of two or more include alloys (more specifically, aluminum alloys, stainless steel, brass, etc.). Among these conductive materials, aluminum and aluminum alloys 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. The charge generation layer may contain a charge generation layer binder resin (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. Examples of the charge generator include phthalocyanine pigments, perylene pigments, bisazo pigments, trisazo pigments, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, indigo pigments, azurenium pigments, cyanine Pigments, inorganic photoconductive materials (more specifically, selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, amorphous silicon, etc.) powders, pyrylium pigments, ansanthrone pigments, triphenylmethane pigments, selenium pigments , Toluidine pigments, pyrazoline pigments and quinacridone pigments. A charge generating agent may be used individually by 1 type, and may be used in combination of 2 or more type.

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

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

  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 photoreceptor having sensitivity in a wavelength region of 700 nm or more. In this case, the charge generator is preferably a phthalocyanine pigment, more preferably a metal-free phthalocyanine and titanyl phthalocyanine, and an X-type metal-free phthalocyanine and Y-type titanyl phthalocyanine because of having a high quantum yield in a wavelength region of 700 nm or more. Is more preferable.

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

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

  The content of the charge generating agent is, for example, preferably 5 parts by mass or more and 1000 parts by mass or less, and 30 parts by mass or more and 500 parts by mass or less with respect to 100 parts by mass of the base resin contained in the charge generation layer. Is more preferable.

(Base resin)
The base resin is not particularly limited as long as it is a resin for a charge generation layer. Examples of the base resin include a thermoplastic resin, a thermosetting resin, and a photocurable resin. Examples of the thermoplastic resin include styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic acid copolymer, styrene-acrylic acid copolymer, polyethylene resin, and 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 Examples include resins, polyvinyl butyral resins, polyether resins, polycarbonate resins, polyarylate resins, and polyester resins. Examples of the thermosetting resin include silicone resins, epoxy resins, phenol resins, urea resins, melamine resins, and other crosslinkable thermosetting resins. Examples of the photocurable resin include an epoxy-acrylic acid resin (epoxy compound acrylic acid adduct) and a urethane-acrylic acid copolymer (urethane compound acrylic acid adduct). As the base resin, a polyvinyl acetal resin is preferably used. A base resin may be used individually by 1 type, and may be used in combination of 2 or more type.

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

(Charge transport layer)
The charge transport layer contains a hole transport agent, a binder resin, and a carboxylic acid 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 necessary.

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

  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 referred to as 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 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or 1 to 6 carbon atoms. The following alkoxy groups or phenyl groups are represented. Q ⁹ and Q ¹⁵ each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. 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 or more and 5 or less, a plurality of Q ⁹ bonded to the same phenyl group may be the same or different. 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. m represents 0 or 1.

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

(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 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 referred to as polyarylate resin R. The charge transport layer can contain 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 general formula (1), k represents 2 or 3. In general formula (1), general formula (2), and general formula (3), X, Y, and Z are each independently the following chemical formula (1A), chemical formula (1B), chemical formula (1C), and chemical formula (1D). , A divalent group represented by the chemical formula (1E), the chemical formula (1F), or the 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 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 valent 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 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 each independently preferably a divalent group represented by the chemical formula (1A), the chemical formula (1C), the chemical formula (1F), or the chemical formula (1G). It is more preferably a divalent group represented by (1A), chemical formula (1F), or chemical formula (1G).

Further, 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. It is preferable. When u ¹ is not 0, X ^a is ^a divalent group represented by the chemical formula (1A) and X ^b is represented by the chemical formula (1F) from the viewpoint of further improving transferability and filming resistance. It is preferable that it is 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) is, 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 repeating units (1-A-1) and (1-A-2) to the total amount of repeating units in the polyarylate resin (1-A) is 0. .80 or more is preferable, 0.90 or more is more preferable, and 1.00 is still more preferable.

When u ¹ in the general formula (1-A) is not 0, the arrangement of the repeating units (1-A-1) and (1-A-2) in the polyarylate resin (1-A) 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, or 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.

Incidentally, s ¹ in the formula (1-A) has a number of number of repeating units of (1-A-2) repeating units contained in the polyarylate resin (1-A) (1- A-1) The percentage of the number of repeating units (1-A-1) 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). 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) contained in the photosensitive layer (a plurality of molecules The average value of the values obtained from (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 one or more selected from repeating units represented by the chemical formula (1-3) are preferred.

(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 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 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 valent 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 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, each of Y ^a and Y ^b is preferably independently a divalent group represented by the chemical formula (1A), the chemical formula (1C), the chemical formula (1F), or the chemical formula (1G). It is more preferably a divalent group represented by (1C) or chemical formula (1F).

Further, from the viewpoint of further improving transferability and filming resistance, in the general formula (2-A), Y ^a is ^a divalent group represented by the chemical formula (1C), and Y ^b is a chemical formula (1F It is preferable that it is a bivalent group represented by this. Further, from the viewpoint of further improving transferability and filming resistance, it is preferable that s ² and u ² each independently represent a number from 30 to 70.

  The polyarylate resin (2-A) is, 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 may be 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 repeating units (2-A-1) and (2-A-2) to the total amount of repeating units in the polyarylate resin (2-A) is 0. .80 or more is preferable, 0.90 or more is more preferable, and 1.00 is still more preferable.

When u ² in the general formula (2-A) is not 0, the arrangement of the repeating units (2-A-1) and (2-A-2) in the polyarylate resin (2-A) 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, or 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 a block composed of a plurality of repeating units (2-A-1) and a block composed of a plurality of repeating units (2-A-2) are arranged.

Incidentally, s ² in formula (2-A) has a number of the number of repeating units (2-A-2) of the repeating units contained in the polyarylate resin (2-A) (2- A-1) The percentage of the number of repeating units (2-A-1) 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). Each of s ² and u ^{2 in} the general formula (2-A) is not a value obtained from one molecular chain, but the entire polyarylate resin (2-A) contained in the photosensitive layer (a plurality of molecules The average value of the values obtained from (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 general 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 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 valent 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 general 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, each of Z ^a and Z ^b is preferably independently a divalent group represented by the chemical formula (1A), the chemical formula (1C), the chemical formula (1F), or the chemical formula (1G). It is more preferably a divalent group represented by (1C) or chemical formula (1F).

Further, from the viewpoint of further improving transferability and filming resistance, in general formula (3-A), Z ^a is ^a divalent group represented by chemical formula (1C), and Z ^b is represented by chemical formula (1F It is preferable that it is a bivalent group represented by this. Further, from the viewpoint of further improving transferability and filming resistance, it is preferable that s ³ and u ³ each independently represent a number from 30 to 70.

  The polyarylate resin (3-A) is, 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 may be 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 repeating units (3-A-1) and (3-A-2) to the total amount of repeating units in the polyarylate resin (3-A) is 0. .80 or more is preferable, 0.90 or more is more preferable, and 1.00 is still more preferable.

When u ³ in the general formula (3-A) is not 0, the arrangement of the repeating units (3-A-1) and (3-A-2) in the polyarylate resin (3-A) 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, or 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) The percentage of the number of repeating units (3-A-1) 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). Each of s ³ and u ^{3 in} the general formula (3-A) is not a value obtained from one molecular chain, but the entire polyarylate resin (3-A) contained in the photosensitive layer (a plurality of molecules The average value of the values obtained from (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 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. Examples of other resins include thermoplastic resins (polyarylate resins other than polyarylate resin R, polycarbonate resins, styrene resins, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, and 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, phenol) 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 80% by mass or more, more preferably 90% by mass or more, and still more preferably 100% by mass with respect to 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, and further preferably 30,000 or more, from the viewpoint of further improving the filming resistance. It is especially preferable 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, and 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 dissolved in a solvent when the charge transport layer is formed, 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 in which an aromatic diol and an aromatic dicarboxylic acid for constituting a repeating unit of the polyarylate resin R are subjected to polycondensation. The method for polycondensing an aromatic diol and an 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. Moreover, the aromatic dicarboxylic acid used for polycondensation may contain other aromatic dicarboxylic acids in addition to the aromatic dicarboxylic acids exemplified above.

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 by the following general formula (1-A-11) or general formula (1-A-21), for example. The aromatic diol for producing the polyarylate resin (2-A) is represented, for example, by 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 by, for example, the following general formula (3-A-11) or general formula (3-A-21). The ka in the general formula (1-A-11) and the kb in the general formula (1-A-21) have the same meanings as ka and kb in the general formula (1-A), respectively. Q ^1a and Q ^2a in general formula (2-A-11) and Q ^1b and Q ^{2b in} general formula (2-A-21) are respectively Q ^1a and Q in general formula (2-A). It is synonymous with ^2a and Q ^1b and Q ^2b . Q ^3a and Q ^4a in general formula (3-A-11) and Q ^3b and Q ^{4b in} general formula (3-A-21) are respectively Q ^3a and Q in general formula (3-A). It is synonymous with ^4a and Q ^3b and Q ^4b .

  The aromatic diol can also be used as a derivative such as diacetate. Moreover, 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 polyarylate resins represented by the following chemical formulas (R1-1) to (R1-6) (hereinafter referred to as 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 sometimes referred to as polyarylate resin (R2-1)).

  Examples of the polyarylate resin (3) include a polyarylate resin represented by the following chemical formula (R3-1) (hereinafter sometimes referred to as polyarylate resin (R3-1)).

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

In general formula (4), general formula (5), and general formula (6), R ¹ , R ² , R ^3, and R ⁴ each independently have 1 to 6 carbon atoms that may have a substituent. It represents 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. 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. When a1 represents 2 or 3, the plurality of R ¹ may be the same as or different from each other. When a2 represents 2 or 3, the plurality of R ² may be the same as or different from each other. When a3 represents 2, two R ^{3 s} may be the same as or different from each other. When a4 represents an integer of 2 or more and 4 or less, the plurality of R ⁴ may be the same as or different from each other. In 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 with respect to 100.00 parts by mass of the binder resin. From the viewpoint of further improving transferability and filming resistance, the content of the acid anhydride AD is preferably 7.00 parts by mass or less, and 5.00 parts by mass with respect to 100.00 parts by mass of the binder resin. More preferably, it is more preferably 4.00 parts by mass or less.

  The photoreceptor according to the first embodiment includes the acid anhydride AD and the polyarylate resin R described above in the charge transport layer, and the content of the acid anhydride AD is 0.02 with respect to 100.00 parts by mass of the binder resin. Transferability is excellent when the content is at least part by mass and no more than 8.00 parts by mass. The reason is presumed as follows.

  In forming the charge transport layer, in the charge transport layer formed by the interaction between the polyarylate resin R and the acid anhydride AD blended in the specific range in the charge transport layer coating solution. There is a tendency that the acid anhydride AD is uniformly dispersed. Therefore, in the photoreceptor according to the first embodiment, the photosensitive layer tends to have an appropriate electrical resistance. As a result, the photoreceptor according to the first embodiment tends to easily hold the electrostatic latent image formed on the photosensitive layer. Therefore, it is considered that the photoconductor according to the first embodiment is excellent in transferability.

  The photoreceptor according to the first embodiment includes the acid anhydride AD and the polyarylate resin R described above in the charge transport layer, and the content of the acid anhydride AD is 0 with respect to 100.00 parts by mass of the binder resin. It is excellent in filming resistance by being 0.02 parts by mass or more and 8.00 parts by mass or less. The reason is presumed as follows.

  When forming the charge transport layer, the charge transport layer is formed by the interaction between the polyarylate resin R and the acid anhydride AD blended in the specific range in the charge transport layer coating solution. There is a tendency for the density to increase. As a result, the surface of the photosensitive layer of the photoreceptor according to the first embodiment tends to increase in hardness. As a result, adhesion of components that cause filming on the surface of the photosensitive layer (more specifically, toner components, paper powder, etc.) tends to be suppressed. Therefore, it is considered that the photoconductor according to the first embodiment is excellent in filming resistance.

In general formula (4), general formula (5) and general formula (6), the alkyl group having 1 to 6 carbon atoms represented by R ¹ , R ² , R ³ and R ⁴ has 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 general formula (4), general formula (5) and general formula (6), the alkoxy group having 1 to 6 carbon atoms represented by R ¹ , R ² , R ³ and R ⁴ has 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 general formula (4), general formula (5), and general formula (6), the aryl group having 6 to 14 carbon atoms represented by R ¹ , R ² , R ^3, and R ⁴ has 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 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 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 an acid anhydride (A5-1)). Is mentioned.

In general formula (6), R ⁴ preferably represents a halogen atom, more preferably 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 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 may be referred to as an acid anhydride (A7-1)). Is mentioned.

  As the acid anhydride AD, the acid anhydride (4) and the acid anhydride (5) are preferable from the viewpoint of further improving the filming resistance by reducing the scratch depth of the photosensitive layer, and the acid anhydride (A4 -1) and acid anhydride (A5-1) are more preferable.

(Electron acceptor compound)
The charge transport layer may contain an electron acceptor compound as necessary. Thereby, there exists a tendency for the hole transport ability of a hole transport agent to improve.

  Examples of electron acceptor compounds include quinone compounds, diimide compounds, hydrazone compounds, malononitrile compounds, thiopyran compounds, trinitrothioxanthone compounds, 3,4,5,7-tetranitro-9-fluorenone compounds, Examples thereof include dinitroanthracene compounds, dinitroacridine compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, and dinitroacridine. Examples of quinone compounds include diphenoquinone compounds, azoquinone compounds, anthraquinone compounds, naphthoquinone compounds, nitroanthraquinone compounds, and dinitroanthraquinone compounds. An electron acceptor compound may be used individually by 1 type, and may be used in combination of 2 or more type.

(Additive)
The charge transport layer may contain an additive as necessary. Examples of additives include deterioration inhibitors (more specifically, antioxidants, radical scavengers, quenchers, UV absorbers, etc.), softeners, surface modifiers, extenders, thickeners, dispersions. Stabilizers, waxes, donors, surfactants, and leveling agents are included.

  Examples of the antioxidant include hindered phenol compounds, hindered amine compounds, thioether compounds, and phosphite compounds. 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). An intermediate | middle layer contains the resin (resin for intermediate | middle layers) used for an inorganic particle and an intermediate | middle layer, for example. When the intermediate layer is interposed, an increase in electrical resistance can be suppressed by smoothing the flow of current generated when the photosensitive member is exposed while maintaining an insulating state capable of suppressing the occurrence of leakage.

  Examples of the inorganic particles include metal (more specifically, aluminum, iron, copper, etc.) particles, metal oxide (more specifically, titanium oxide, alumina, zirconium oxide, tin oxide, zinc oxide, etc.). And particles of a non-metal oxide (more specifically, silica or the like). These inorganic particles may be used individually by 1 type, and may use 2 or more types together. The inorganic particles may be subjected to a surface treatment.

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

[4. Photoconductor manufacturing method]
The method for producing a photoreceptor 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 generation layer forming step and a charge transport layer forming step.

  In the charge generation layer forming step, first, a charge generation layer coating solution is prepared. Next, a charge generation layer coating solution is applied onto the conductive substrate. Next, by drying by an appropriate method, at least a part of the solvent contained in the applied charge generation layer coating solution is removed to form a charge generation layer. The charge generation layer coating solution includes, for example, a charge generation agent, a base resin, and a solvent. Such a coating solution for charge generation layer 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 necessary.

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

  Hereinafter, details of the photosensitive layer forming step will be described. If the solvent contained in the coating solution for charge generation layer and the coating solution for charge transport layer (hereinafter sometimes collectively referred to as coating solution) can dissolve or disperse each component contained in the coating solution, There is no particular limitation. Examples of the solvent include alcohol (more specifically, methanol, ethanol, isopropanol, butanol, etc.), aliphatic hydrocarbon (more specifically, n-hexane, octane, cyclohexane, etc.), aromatic hydrocarbon ( More specifically, benzene, toluene, о-xylene, m-xylene, p-xylene, etc.), halogenated hydrocarbons (more specifically, dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene, etc.), ether (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. Of these solvents, non-halogen solvents are preferably used.

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

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

  The method for applying the coating solution is not particularly limited as long as the method can uniformly apply the coating solution. 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 it is a method capable of evaporating at least a part of the solvent in the coating solution. Examples of the removal method include heating, reduced pressure, and combined use of heating and reduced pressure. More specifically, a method of performing heat treatment (hot air drying) using a high-temperature dryer or a vacuum dryer can be mentioned. The heat treatment conditions are, for example, a temperature of 40 ° C. or higher and 150 ° C. or lower and a time of 3 minutes or longer and 120 minutes or shorter.

  Note that the method for manufacturing a photoreceptor may further include a step of forming an intermediate layer, if necessary. A known method can be selected as appropriate for the step of forming the intermediate layer.

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

<Second Embodiment: Image Forming Apparatus>
The outline of the image forming apparatus according to the second embodiment will be described below with reference to FIG. The image forming apparatus 100 includes an image carrier 30, a charging unit 42, an exposure unit 44, a developing unit 46, and a transfer unit 48. The image carrier 30 is the photoconductor according to the first embodiment described above. The charging unit 42 charges the surface of the image carrier 30. The exposure unit 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 object). 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 the occurrence of image defects. 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 photoconductor 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 image defects (more specifically, image defects caused by a decrease in transferability, image defects caused by filming, and the like). Hereinafter, as an example of an image defect, an image defect caused by a decrease in transferability will be described.

  When the transferability is lowered, the toner that cannot be transferred onto the image carrier 30 after the toner image is transferred to the recording medium P remains. The remaining toner may be transferred to an image formed after the next round of the reference circumference of the image carrier 30 (any one round when images are continuously formed). An image defect in which an image reflecting such an 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, the image defect resulting from a transferability fall is further demonstrated. 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 regions corresponding to one rotation of the image carrier. The image 118 in the area 112 includes a rectangular solid image (image density 100%). Regions 114 and 116 are all blank images (image density 0%) on the design image. An image 118 of the region 112 is first formed along the direction A (conveying direction A) in which the recording medium is conveyed, then an image of the region 114 is formed, and finally an image of the region 116 is formed. When the circumference in which the image 118 of the area 112 is formed is a reference circumference, the image of the area 114 is an image corresponding to one round of the next round of the reference circumference. Further, the image in the region 116 is an image corresponding to one round after the reference circumference.

  In this case, when transferability is lowered, 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 region 114. An image 122 reflecting the image 118 is formed in the area 116. As described above, the image defect due to the decrease in transferability occurs in a cycle in which the circumference of the image carrier is a unit. In addition, images reflecting the image 118 are easily formed on both ends of the recording medium. This is considered to be because the pressing force to both ends of the recording medium is relatively strong. Here, the both end portions of the recording medium are, for example, both end portions (region 120L and region 120R) in the direction B orthogonal to the transport direction A in the region 114 of the recording medium, and both end portions (regions) in the direction 116 in the region 116. 122L and region 122R).

  Hereinafter, returning to FIG. 4, details of the image forming apparatus 100 will be described. The image forming apparatus 100 is a tandem color image forming apparatus. The image forming apparatus 100 employs a direct transfer method. Normally, in an image forming apparatus that employs a direct transfer method, an image carrier is in contact with a recording medium, so that minute components are likely 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 photoconductor according to the first embodiment is excellent in filming resistance. Therefore, when the image bearing member 30 includes the photoconductor according to the first embodiment, even the image forming apparatus 100 adopting the direct transfer method can suppress the occurrence of image defects due to filming.

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

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

  Each of the image forming units 40a to 40d sequentially superimposes toner images of a plurality of colors (for example, four colors of black, cyan, magenta, and yellow) 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 being in contact with the surface of the image carrier 30. Usually, in an image forming apparatus provided with a charging roller, image defects are likely to occur. However, the image forming apparatus 100 includes the photoconductor according to the first embodiment as the image carrier 30. The photoconductor according to the first embodiment is excellent in transferability and filming resistance. Therefore, even if the image forming apparatus 100 includes a charging roller as the charging unit 42, the occurrence of image defects is suppressed. As described above, the image forming apparatus 100 as an example of the second embodiment employs the contact charging method. Examples of other contact charging type charging units include a charging brush. The charging unit may be a non-contact type. Examples of the non-contact 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), and among these, a DC voltage is preferable. The DC voltage has the following advantages over the AC voltage and the superimposed voltage. When the charging unit 42 applies only a DC voltage, the voltage value 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. Further, when the charging unit 42 applies only a 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. As a result, an electrostatic latent image is formed on the surface of the image carrier 30. The electrostatic latent image is formed based on image data input to the image forming apparatus 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 employ a system (contact development system) that develops the electrostatic latent image as a toner image while being in contact with the surface of the image carrier 30. Usually, an image defect is likely to occur in an image forming apparatus employing a contact development method. However, the image forming apparatus 100 includes the photoconductor according to the first embodiment as the image carrier 30. The photoconductor according to the first embodiment is excellent in transferability and filming resistance. Therefore, even if the image forming apparatus 100 including such a photoconductor employs a contact development method, the occurrence of image defects is suppressed.

  The developing unit 46 can clean the surface of the image carrier 30. In other words, the image forming apparatus 100 can employ a so-called cleaner-less method. In this case, the developing unit 46 can remove residual components on the surface of the image carrier 30. Normally, 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 cleanerless type image forming apparatus, residual components on the surface of the image carrier are not scraped off. Therefore, in the image forming apparatus that employs the cleaner-less method, residual components are likely to remain on the surface of the image carrier, and image defects due to filming are likely to occur. However, the image forming apparatus 100 includes the photoconductor of the first embodiment having excellent filming resistance as the image carrier 30. Therefore, even if the image forming apparatus 100 including such a photoconductor employs a cleaner-less method, residual components, particularly minute components (for example, paper dust) of the recording medium P hardly remain 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 development method is employed, and there is a difference in peripheral speed (rotational speed) between the image carrier 30 and the developing unit 46. It is preferable to be 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 faster 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 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. An example of the transfer unit 48 is a transfer roller.

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

  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 image forming apparatus, but the image forming apparatus according to the second embodiment is not limited to this, and a rotary system or the like may be employed. 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 only one image forming unit, for example. 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 an 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. Next, 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 each of the image forming units 40a to 40d (FIG. 4), for example. These process cartridges include a unitized portion. The unitized portion includes the image carrier 30. Further, the unitized portion may include at least one selected from the group consisting of the charging unit 42, the exposure unit 44, the developing unit 46, and the 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 removal unit (not shown). The process cartridge is designed to be detachable from the image forming apparatus 100, for example. The process cartridge in this case is easy to handle, and when the sensitivity characteristics of the image carrier 30 are deteriorated, 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, thereby suppressing image defects.

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

<Material of photoconductor>
The following hole transport agent, binder resin, and acid anhydride were prepared as materials for producing a photoreceptor.

[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).

  Below, the synthesis | combining method of polyarylate resin (R1-1)-(R1-6), (R2-1) and (R3-1) is demonstrated.

[Synthesis Method of Polyarylate Resin (R1-1)]
A 1 L 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, 12.1-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 added. Next, the inside of the reaction vessel was purged with argon. Thereafter, 600 mL of water was further added to 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 contents of the reaction vessel were cooled, and the internal temperature of the reaction vessel was lowered to 10 ° C. In this way, an alkaline aqueous solution was prepared.

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

  Next, while maintaining the temperature of the alkaline aqueous solution at 10 ° C. and stirring the contents of the reaction vessel, the chloroform solution was added to the alkaline aqueous solution to initiate the 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 8 times with a separatory 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 put into a 3 L Erlenmeyer flask. The obtained filtrate was slowly dropped into the Erlenmeyer flask to obtain a precipitate. The precipitate was filtered off. The obtained precipitate was vacuum-dried 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.

[Synthesis Method of Polyarylate Resins (R1-2) to (R1-6), (R2-1) and (R3-1)]
The polyarylate resins (R1-2) to (R1-6), (R2-1), and (R3) are the same as the polyarylate resin (R1-1) except that the changes are as described below. -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 halogenated aryloyl. The total amount of aromatic diol in each synthesis of polyarylate resins (R1-2) to (R1-6), (R2-1) and (R3-1) is the polyarylate resin (R1-1). The total amount of aromatic diol in the synthesis of The total amount of halogenated aryloyl in the synthesis of each of the polyarylate resins (R1-2) to (R1-6), (R2-1), and (R3-1) depends on the synthesis of the polyarylate resin (R1-1). It was the same as the total amount of halogenated aryloyl in

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

<Manufacture of photoconductor>
[Photoreceptor (A-1)]
Hereinafter, a method for producing the photoreceptor (A-1) according to Example 1 will be described.

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

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

(Formation of charge generation layer)
Y-type titanyl phthalocyanine (1.5 parts by mass) and a polyvinyl acetal resin (“SREC 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 to disperse the material in the solvent. This dispersion was filtered using a filter having an opening of 3 μm. This prepared the coating liquid for charge generation layers. The obtained coating solution for charge generation layer was applied on the intermediate layer formed as described above using a dip coating method and dried at 50 ° C. for 5 minutes. As a result, 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 transport agent (HTM11), 0.50 parts by mass of a hindered phenol antioxidant (“Irganox (registered trademark) 1010” manufactured by BASF Corporation) as an additive, and an acid anhydride (A4-1) 1.00 mass part and 100.00 mass parts of polyarylate resin (R1-1) as 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. Using an ultrasonic disperser, these materials were dispersed in a solvent for 2 minutes to prepare a charge transport layer coating solution.

  Next, the charge transport layer coating solution was applied onto the charge generation layer by the same operation as the charge generation layer coating solution described above. Then, it was made to dry at 120 degreeC for 40 minute (s), the charge transport layer (film thickness of 20 micrometers) was formed on the charge generation layer, and the photoreceptor (A-1) was obtained. The obtained photoreceptor (A-1) was visually observed to confirm that the surface of the charge transport layer was not crystallized.

[Photosensitive members (A-2) to (A-13) and photosensitive members (B-1) to (B-5)]
The photoreceptors (A-2) to (A-13) and the photoreceptors (B-1) to (B-5) were respectively the same as the photoreceptor (A-1) except that the following points were changed. Manufactured. The obtained photoreceptors (A-2) to (A-13) and the photoreceptors (B-1) to (B-5) were observed visually. Among these, regarding the photoreceptors (B-3) and (B-4), the surface of the charge transport layer was crystallized. For other photoreceptors, the surface of the charge transport layer was not crystallized.

(change point)
The polyarylate resin (R1-1) as the binder resin used for the production of the photoreceptor (A-1) was changed to the polyarylate resin shown in Table 1. The acid anhydride (A4-1) and its content used for the production of the photoreceptor (A-1) were changed to the acid anhydride and its content shown in Table 1. In addition, A4-1, A5-1, A6-1, A7-1, and A10-1 of “kind” in the column “acid anhydride” in Table 1 are acid anhydrides (A4-1) and (A5- 1), (A6-1), (A7-1) and (A10-1) are shown. The “content” of the column “acid anhydride” in Table 1 is the number of parts by mass relative to 100.00 parts by mass of the polyarylate resin used.

<Method for measuring physical properties of photosensitive layer>
[Measurement of elastic power]
The elastic power of the photosensitive layer was measured for each of the obtained photoreceptors (A-1) to (A-13) and photoreceptors (B-1) to (B-5). The elastic power of the photosensitive layer was measured using a microhardness meter (“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. Measured by performing B and Step C. In Step A, a diamond indenter is used to apply a load to the photosensitive layer over 30 seconds so that the maximum load is 9.8 mN. When the load is applied, the maximum deformation work (EW ₁ : plastic deformation) of the photosensitive layer is applied. Work + elastic deformation work). In Step B, the amount of restoration of the photosensitive layer (EW ₂ : work of elastic deformation) is measured when the load is removed by removing the load applied to the photosensitive layer by separating the diamond indenter from the photosensitive layer over 30 seconds. did. In Step C, from the measured maximum deformation work (EW ₁ ) of the photosensitive layer and the restoration amount (EW ₂ ) of the photosensitive layer, the equation “elastic work rate (%) = (100 × EW ₂ ) / EW ₁ ” is used. The elastic power of the photosensitive layer was determined. The results are shown in Table 2. As the elastic power of the photosensitive layer shows a larger value, the occurrence of filming tends to be suppressed. The measurement conditions for 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

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

  Hereinafter, with reference to FIG. 6, the scratching apparatus 200 prescribed | regulated by JISK5600-5-5 is demonstrated. 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 portion 204, two shaft support portions 205, a base 206, two rail portions 207, and a weight plate 208. And a constant speed motor (not shown). A weight 209 is placed on the weight plate 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 within 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 the other 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 side of the other end 201 c on the upper surface 201 a of the fixing base 201. The fixing tool 202 fixes the measurement target (photosensitive member 1) to the upper surface 201a of the fixing base 201.

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

  The support arm unit 204 supports the scratch needle 203. The support arm 204 rotates around the support shaft 204a in a direction in which the scratch needle 203 approaches and separates from the photoreceptor 1.

  The two shaft support parts 205 support the support arm part 204 in a rotatable manner.

  The base 206 includes 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. The two rail portions 207 are each provided in parallel with the longitudinal direction (X-axis direction) of the fixed base 201. A fixed base 201 is attached between the two rail portions 207. Along the rail portion 207, the fixed base 201 can move horizontally 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 portion 204. A weight 209 is placed on the weight plate 208.

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

  Hereinafter, a method for measuring the scratch depth will be described. The method for measuring the scratch depth includes the following first step, second step, third step, and fourth step. As the scratch device 200, a surface property measuring machine (“HEIDON TYPE 14” manufactured by Shinto Kagaku Co., Ltd.) was used. The scratch depth was measured in an environment at a temperature of 23 ° C. and a humidity of 50% RH. The shape of the photoreceptor 1 was a drum shape (cylindrical shape).

(First step)
In the first step, the photosensitive member 1 is fixed to the upper surface 201 a of the fixing base 201 so that the longitudinal direction of the photosensitive member 1 is parallel to the longitudinal direction of the fixing base 201. At this time, the photoconductor 1 was attached so that the central axis L ₂ (rotation axis) direction of the photoconductor 1 was parallel to the longitudinal direction of the fixed base 201.

(Second step)
In the second step, the scratch needle 203 was brought into contact with the surface 3c of the photosensitive layer 3 perpendicularly. With reference to FIGS. 7 and 8 in addition to FIG. 6, a method of bringing the scratch needle 203 vertically into contact with the surface 3 c of the photosensitive layer 3 of the drum-shaped photoreceptor 1 will be described.

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

The scratching needle 203 was brought close to the photoreceptor 1 so that the extension line of the central axis A ₁ of the scratching needle 203 was perpendicular to the upper surface 201 a of the fixed base 201. Next, on the surface 3c of the photosensitive layer 3 of the photoreceptor 1, the tip 203b of the scratching needle 203 is brought into contact with a point (contact point P ₂ ) farthest in the vertical direction (Z-axis direction) from the upper surface 201a of the fixed base 201. I let you. 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, the line segment connecting the contact point P _{1 on the} upper surface 201 a and the contact point P _{2 on the} tip 203 _b was orthogonal to the central axis L ₂ of the photoreceptor 1. The tangent line A ₂ is a tangent line at the contact point P ₂ of the outer circumference circle formed by the cross section of the photoreceptor 1 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 from the scratching needle 203 to the photosensitive layer 3 in a state where the scratching needle 203 was in contact with the surface 3c of the photosensitive layer 3 perpendicularly. Specifically, 10 g weight 209 was placed on the weight pan 208. In this state, the fixed base 201 was moved. Specifically, the constant speed motor was driven, and the fixed base 201 was moved 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. The second position N ₂ was located downstream from the first position N ₁ . The downstream side is a side where the fixed base 201 is positioned in a direction away 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 photosensitive member 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 of the fixed base 201 and the photosensitive member 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 fixing base 201 and the photosensitive member 1, the 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, 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. The line L ₃ was parallel to the upper surface 201 a of the fixed base 201 and the central axis L ₂ of the photoreceptor 1. The line L ₃ was perpendicular to the central axis A ₁ of the scratch needle 203.

(Fourth 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 photoreceptor 1 was removed from the fixed base 201. Using a three-dimensional interference microscope (Bruker “WYKO NT-1100”), the scratch S formed on the photosensitive layer 3 of the photoreceptor 1 is observed at a magnification of 5 times, and the depth Ds of the scratch S is measured. did. The depth Ds of the scratch S was the distance from the tangent line A ₂ to the valley of the scratch S. The maximum value among the depths Ds of the scratches S was defined as the scratch depth. The results are shown in Table 2. As the scratch depth of the photosensitive layer 3 shows a smaller value, the occurrence of filming tends to be suppressed.

<Evaluation method>
[Evaluation of filming resistance]
The filming resistance shown below was evaluated for each of the obtained photoreceptors (A-1) to (A-13) and photoreceptors (B-1) to (B-5).

  As an evaluation machine, a color printer (“ECOSYS (registered trademark) FS-C5400DN” manufactured by Kyocera Document Solutions Co., Ltd.) was used. This evaluation machine was a modified machine modified to a cleaner-less system. That is, in this evaluation machine, the cleaning blade is removed, and the developing unit is modified to clean the surface of the photoreceptor. This evaluation machine adopted a direct transfer system. This evaluator 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 Inc. was used as the evaluation paper. As an evaluation toner, “TK-131” manufactured by Kyocera Document Solutions Co., Ltd. was used.

  The photoconductor was mounted on an evaluation machine, and the charging potential was set to -600V. Next, an image I (pattern image with a printing rate of 1%) was printed on 2,000 sheets at an interval of 16 seconds in an environment of a temperature of 32 ° C. and a humidity of 85% RH. Next, an image I was printed on 2,000 sheets at intervals of 16 seconds under an environment of a temperature of 10 ° C. and a humidity of 15% RH. After printing, the evaluation machine equipped with the photoconductor is left in an environment of temperature 10 ° C. and humidity 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 a white spot was confirmed visually and the following reference | standard evaluated. The results are shown in Table 2. Note that when filming occurs on the surface of the photoreceptor, white spots tend to occur in the formed image.

(Filming resistance evaluation criteria)
A (particularly good): No white spots were confirmed in the evaluation image (E-1).
B (good): Slight white spots were confirmed in the evaluation image (E-1), but white spots were not problematic in actual use.
C (defect): White spots were clearly confirmed in the evaluation image (E-1).

[Evaluation of transferability]
The following transferability was evaluated for each of the obtained photoreceptors (A-1) to (A-13) and photoreceptors (B-1) to (B-5). Note that 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 by the transfer roller to the photoconductor was set to +25 μA. Next, a printing pattern (printing rate 4%) was printed on 2,000 sheets at an interval of 16 seconds under an environment of a temperature of 32 ° C. and a humidity of 85% RH, and a printing test was performed. Immediately after the 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. A region 152 is a region corresponding to one rotation of the image carrier. The image 158 in the region 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 is an entire blank image (image density 0%). The image 158 of the area 152 is first formed along the sheet conveyance direction A (conveyance direction A), then the image of the area 154 is formed, and finally the image of the area 156 is formed. When the circumference in which the image 158 in the area 152 is formed is the reference circumference, the image in the area 154 is an image corresponding to one round of the next round of the reference circumference. In addition, the image in the region 156 is an image corresponding to one round after the reference circumference. Note that the area 160 is an area corresponding to the image 158 in the area 154. The area 162 is an area corresponding to the image 158 in the area 156.

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

(Evaluation criteria for transferability)
A (particularly good): An image reflecting the image 158 was not confirmed in the region 160 and the region 162.
B (good): In the region 160, images reflecting the image 158 were slightly confirmed at both ends in the direction B orthogonal to the direction A, but no image reflecting the image 158 was confirmed in the region 162.
C (defect): Images reflecting the image 158 were 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 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 formula (4), the general formula (5), the general formula (6), or the general formula (7). , (A5-1), (A6-1) and (A7-1) were contained in the charge transport layer. The photoreceptors (A-1) to (A-13) had an acid anhydride content of 0.03 parts by mass or more and 7.50 parts by mass or less with respect to 100.00 parts by mass of the binder resin. As shown in Table 2, the evaluation results of the filming resistance of the photoreceptors (A-1) to (A-13) were A (particularly good) or B (good). The photoreceptors (A-1) to (A-13) had a transferability evaluation result of A (particularly good) or B (good).

  As shown in Table 1, the photoreceptor (B-1) contains a polyarylate resin (R-10) not included in the general formula (1), the general formula (2), and the general formula (3) in the charge transport layer. Was. The photoreceptor (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 photoreceptors (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 photoreceptor (B-5) contains an acid anhydride (A10-1) not included in the general formula (4), the general formula (5), the general formula (6), and the general formula (7) in the charge transport layer. It was. As shown in Table 2, the evaluation results of the filming resistance of the photoreceptors (B-1) to (B-5) were C (poor). The photoreceptors (B-2) to (B-5) had a transfer evaluation result of C (defect).

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

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

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Conductive substrate 3 Photosensitive layer 3a Charge generation layer 3b Charge transport layer 4 Intermediate layer

Claims (18)

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 includes a charge generation agent,
The charge transport layer includes a hole transport agent, a binder resin, and a carboxylic acid 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 acid 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 acid anhydride is 0.02 parts by mass or more and 8.00 parts by mass or less with respect to 100.00 parts by mass of the binder resin.

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

(In the general formula (4), general formula (5) and general formula (6),
R ¹ , R ² , R ³ and R ⁴ each independently represents an alkyl group having 1 to 6 carbon atoms which may have a substituent, and 1 to 6 carbon atoms which may have a substituent. Represents the following alkoxy group, 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 to 2,
a4 represents an integer of 0 to 4,
when a1 represents 2 or 3, the plurality of R ¹ may be the same as or different from each other;
when a2 represents 2 or 3, the plurality of R ² may be the same or different from each other;
when a3 represents 2, two R ^{3 s} may be the same or different from each other;
when a4 represents an integer of 2 or more and 4 or less, the plurality of R ⁴ may be the same as 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 photosensitive 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 photosensitive member according to any one of claims 1 to 3, wherein the hole transport 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 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or phenyl Represents a group,
Q ⁹ and Q ¹⁵ each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group,
b represents an integer of 0 to 5,
c represents an integer of 0 or more and 4 or less,
when b represents an integer of 2 or more and 5 or less, 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 as 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 the general formula (2). The polyarylate resin is selected from repeating units represented by the following chemical formula (1-1), chemical formula (1-2), and chemical formula (1-3) as the repeating unit represented by the general formula (1). The electrophotographic photosensitive member according to claim 5, comprising at least one of the following.

The polyarylate resin includes a repeating unit represented by the following chemical formula (2-1) and a repeating unit represented by the following chemical formula (2-2) as the repeating unit represented by the general formula (2). The electrophotographic photosensitive member according to claim 5.

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

In the general formula (1), k represents 3,
In the general formula (1), general formula (2) and general formula (3),
X, Y and Z are each independently a divalent group represented by the chemical formula (1A), the chemical formula (1C), the chemical formula (1F) or the chemical formula (1G);
Q ¹ and Q ² represent a hydrogen atom,
Q ³ and Q ⁴ represent a methyl group, an electrophotographic photosensitive member according to any one of claims 1-4.   The electrophotographic photoreceptor according to claim 1, wherein the carboxylic acid anhydride is a compound represented by the general formula (4) or the general formula (5). The carboxylic acid anhydride is a compound represented by the general formula (6),
In the general formula (6), R ⁴ represents a halogen atom,
The electrophotographic photosensitive member according to claim 1, wherein a4 represents 1 or 2. The carboxylic acid anhydride is a compound represented by the general formula (7),
The electrophotographic photosensitive member according to any one of claims 1 to 9, wherein G in the general formula (7) represents an oxygen atom. The carboxylic acid anhydride is a compound represented by the following chemical formula (A4-1), chemical formula (A5-1), chemical formula (A6-1), or chemical formula (A7-1). The electrophotographic photosensitive member according to any one of the above.

  A process cartridge comprising the electrophotographic photosensitive member according to claim 1. An image carrier;
A charging unit for charging the surface of the image carrier;
An exposure unit that exposes the surface of the charged image carrier to form an electrostatic latent image on the surface of the image carrier;
A developing unit for developing the electrostatic latent image as a toner image;
An image forming apparatus comprising: a transfer unit that transfers the toner image from the image carrier to a transfer target;
The image carrier is the electrophotographic photosensitive member according to any one of claims 1 to 13,
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 and the transfer body into contact with each other.   The image forming apparatus according to claim 15, wherein the transfer target is a recording medium.   The image forming apparatus according to claim 15, wherein the developing unit cleans the surface of the image carrier.   The image forming apparatus according to claim 15, wherein the charging unit is a charging roller.

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