JP2018120056A - Electrophotographic photoreceptor, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that is excellent in filming resistance.SOLUTION: An electrophotographic photoreceptor comprises a conductive substrate, and a photosensitive layer including a charge generating layer and a charge transport layer; the charge transport layer contains a hole transport agent, a binder resin, and an addition agent. The charge transport layer is a single layer and provided as an outermost surface layer. The binder resin is represented by the general formula (1), and the addition agent by the general formula (4). The photosensitive layer has an elastic power of 47.0% or more.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 or a multifunction machine). The electrophotographic photoreceptor includes a photosensitive layer. As the electrophotographic photosensitive member, for example, a single layer type electrophotographic photosensitive member or a multilayer type electrophotographic photosensitive member is used. The single-layer type electrophotographic photosensitive member includes a single-layer photosensitive layer having a charge generation function and a charge transport function. The multilayer electrophotographic photoreceptor includes, as a photosensitive layer, a charge generation layer having a charge generation function and a charge transport layer having a charge transport function.

  Patent Document 1 describes an electrophotographic photosensitive member containing at least one polyarylate resin represented by the following chemical formula as a binder resin.

JP-A-56-135844

  However, the electrophotographic photoreceptor described in Patent Document 1 has insufficient filming resistance.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an electrophotographic photoreceptor excellent in filming resistance. It is another object of the present invention to provide a process cartridge and an image forming apparatus that suppress the occurrence of image defects due to filming.

  The electrophotographic photoreceptor of the present invention includes a conductive substrate and a photosensitive layer. The photosensitive layer includes 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 an additive. The charge transport layer is a single layer and is provided as the outermost layer. The binder resin includes a polyarylate resin represented by the general formula (1), (2), or (3). The additive is represented by the general formula (4). The elastic power of the photosensitive layer is 47.0% or more.

In the general formula (1), X ¹ and Y ¹ are each a divalent group represented by the chemical formula (A), (B), (C), (D), (E) or (F). X ¹ and Y ¹ are different from each other. kr and kt each independently represent 2 or 3. r ¹ and s ¹ each independently represent a positive number satisfying the mathematical expressions (1a) and (1b). t ¹ and u ¹ each independently represents a number of 0 or more that satisfies the mathematical formulas (1a) and (1b).
r ¹ + s ¹ + t ¹ + u ¹ = 100 (1a)
r ¹ + t ¹ = s ¹ + u ¹ (1b)

In the general formula (2), R ²¹ , R ²² , R ²³ and R ²⁴ each independently represent a hydrogen atom or a methyl group. X ² and Y ² each represent a divalent group represented by the chemical formula (A), (B), (C), (D), (E) or (F), and X ² and Y ² Are different from each other. r ² , s ² , t ² and u ² each independently represent a positive number satisfying the mathematical expressions (2a), (2b) and (2c).
r ² + s ² + t ² + u ² = 100 (2a)
r ² + t ² = s ² + u ² (2b)
0.30 ≦ s ² / (s ² + u ² ) ≦ 0.70 (2c)

In the general formula (3), R ³¹ , R ³² , R ³³ and R ³⁴ each independently represents a hydrogen atom or a methyl group. X ³ and Y ³ each represent a divalent group represented by the chemical formula (A), (B), (C), (D), (E) or (F), and X ³ and Y ³ Are different from each other. r ³ , s ³ , t ³ and u ³ each independently represent a positive number satisfying the mathematical expressions (3a), (3b) and (3c).
r ³ + s ³ + t ³ + u ³ = 100 (3a)
r ³ + t ³ = s ³ + u ³ (3b)
0.30 ≦ s ³ / (s ³ + u ³ ) ≦ 0.70 (3c)

In the general formula (4), R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl having 6 to 14 carbon atoms which may have a halogen atom. Group represents an aralkyl group having 7 to 20 carbon atoms. R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ may each independently have a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. It represents a good aryl group having 6 to 14 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an amino group which may have a phenyl group, or a nitro group. Of R ³ , R ⁴ , R ⁵ and R ⁶ , two substituents bonded to adjacent carbon atoms in the benzene ring may be bonded to each other to form an aromatic ring. Of R ⁷ , R ⁸ , R ⁹ and R ¹⁰ , two substituents bonded to adjacent carbon atoms in the benzene ring may be bonded to each other to form an aromatic ring.

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

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

  The electrophotographic photoreceptor of the present invention is excellent in filming resistance. In addition, the process cartridge and the image forming apparatus of the present invention suppress the occurrence of image defects due to filming.

(A) And (b) is a fragmentary sectional view which respectively shows the structure of the electrophotographic photoreceptor which concerns on 1st embodiment of this invention. It is a figure which shows an example of the structure of the image forming apparatus which concerns on 2nd embodiment. It is a ¹ H-NMR spectrum of a polyarylate resin represented by the chemical formula (R-1). It is a ¹ H-NMR spectrum of a polyarylate resin represented by the chemical formula (R-2). It is a ¹ H-NMR spectrum of a polyarylate resin represented by the chemical formula (R-3). It is a ¹ H-NMR spectrum of a polyarylate resin represented by the chemical formula (R-7). It is a ¹ H-NMR spectrum of a polyarylate resin represented by the chemical formula (R-8). It is a figure which shows an example of a structure of a scratching apparatus. It is sectional drawing in the IX-IX line of FIG. FIG. 9 is a side view of the fixing base, the scratching needle, and the electrophotographic photosensitive member shown in FIG. 8. It is a figure which shows the scratch formed in the surface of the photosensitive layer.

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. The present invention can be implemented with appropriate modifications within the scope of the object of the present invention. In addition, about the location where description overlaps, although description may be abbreviate | omitted suitably, the summary of invention is not limited. 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, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 3 carbon atoms, carbon Unless otherwise specified, an alkoxy group having 1 to 6 atoms, an aryl group having 6 to 14 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms have the following meanings.

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

  The alkyl group having 1 to 8 carbon atoms, the alkyl group having 1 to 6 carbon atoms, the alkyl group having 1 to 4 carbon atoms, and the alkyl group having 1 to 3 carbon atoms are each linear. Or it is branched and unsubstituted. Examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, and neopentyl group. Hexyl group, heptyl group or octyl group. Examples of the alkyl group having 1 to 6 carbon atoms are groups having 1 to 6 carbon atoms among the groups described as examples of alkyl groups having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms are groups having 1 to 4 carbon atoms among the groups described as examples of alkyl groups having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms are groups having 1 to 3 carbon atoms among the groups described as examples of alkyl groups having 1 to 8 carbon atoms.

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

  Examples of the aryl group having 6 to 14 carbon atoms include an unsubstituted aromatic monocyclic hydrocarbon group having 6 to 14 carbon atoms and an unsubstituted aromatic condensed bicyclic carbon group having 6 to 14 carbon atoms. A hydrogen group or an unsubstituted aromatic condensed tricyclic hydrocarbon group having 6 to 14 elemental atoms. 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.

  The aralkyl group having 7 to 20 carbon atoms is a group in which an alkyl group having 1 to 6 carbon atoms and an aryl group having 6 to 14 carbon atoms are bonded. An aralkyl group having 7 to 20 carbon atoms is unsubstituted. Examples of the aralkyl group having 7 to 20 carbon atoms include phenylmethyl group, phenylethyl group, phenylpropyl group, phenylbutyl group, phenylpentyl group, phenylhexyl group, and naphthylmethyl group.

<First embodiment: electrophotographic photoreceptor>
The electrophotographic photoreceptor according to the first embodiment (hereinafter sometimes referred to as a photoreceptor) is excellent in filming resistance. The reason is presumed as follows.

  To help understanding, first, filming on the surface of the photoreceptor will be described. Filming is a phenomenon in which minute components adhere to and adhere to the surface of the photoreceptor. An example of the minute component is a toner component, and more specifically, the toner or an external additive released from the toner. Another example of the minute component is a non-toner component, and more specifically, a minute component (for example, paper dust) of the recording medium.

  In the photoreceptor according to the first embodiment, the charge transport layer includes a hole transport agent, a binder resin, and an additive. The binder resin is a polyarylate resin represented by the general formula (1), (2) or (3) (hereinafter, each may be referred to as a polyarylate resin (1), (2) or (3)). including. The additive includes a compound represented by the general formula (4) (hereinafter sometimes referred to as additive (4)). Since the polyarylate resin (1), (2) or (3) and the additive (4) are excellent in compatibility, there is a tendency to suppress a decrease in the elastic power of the photosensitive layer. For this reason, on the surface of the charge transport layer, it is difficult to form a concavo-convex shape derived from scratches, and it is difficult for a minute component to be fixed. Therefore, it is considered that the photoconductor according to the first embodiment is excellent in filming resistance.

  Next, the structure of the photoconductor 30 according to the first embodiment will be described with reference to FIG. FIG. 1 is a partial cross-sectional view showing the structure of the photoreceptor 30 according to the first embodiment.

  As shown in FIG. 1A, the photoreceptor 30 includes a conductive substrate 31 and a photosensitive layer 32. The photosensitive layer 32 includes a charge generation layer 321 and a charge transport layer 322. The photoreceptor 30 is a laminated electrophotographic photoreceptor. The charge transport layer 322 is a single layer. The charge transport layer 322 is provided as the outermost surface layer of the photoreceptor 30. In the photoreceptor 30, for example, a charge generation layer 321 is provided on the conductive substrate 31, and a charge transport layer 322 is provided on the charge generation layer 321. The photosensitive layer 32 may be provided directly on the conductive substrate 31. The charge generation layer 321 may be provided directly on the conductive substrate 31.

  As shown in FIG. 1B, the photoreceptor 30 may include, for example, a conductive substrate 31, an intermediate layer 33 (undercoat layer), and a photosensitive layer 32. The photosensitive layer 32 may be provided on the conductive substrate 31 via the intermediate layer 33. The intermediate layer 33 may be provided between the conductive substrate 31 and the charge generation layer 321. The intermediate layer 33 may be provided between the charge generation layer 321 and the charge transport layer 322.

  The thickness of the charge generation layer 321 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 322 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 photoconductor 30 has been described above with reference to FIG. Hereinafter, the photoreceptor will be described in more detail.

<Conductive substrate>
The conductive substrate is not particularly limited as long as it can be used as the conductive substrate of the photoreceptor. It is sufficient that at least the surface portion of the conductive substrate is a material having conductivity. An example of the conductive substrate is a conductive substrate made of a conductive material. Another example of the conductive substrate is a conductive substrate coated with a conductive material. Examples of the conductive material include aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, and indium. These materials having conductivity may be used alone or in combination of two or more. Examples of the combination of two or more include alloys (more specifically, aluminum alloy, stainless steel, brass, etc.). Among these materials having conductivity, aluminum or an aluminum alloy is 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 or a drum shape. Further, the thickness of the conductive substrate can be appropriately selected according to the shape of the conductive substrate.

<Photosensitive layer>
The photosensitive layer includes a charge generation layer and a charge transport layer. The charge generation layer includes a charge generation agent. The charge generation layer may contain a charge generation layer binder resin (hereinafter sometimes referred to as a base resin). The charge transport layer includes a hole transport agent, a binder resin, and an additive (4). The charge generation layer and the charge transport layer may contain additives other than the additive (4) as necessary.

(Elastic power of photosensitive layer)
The elastic power of the photosensitive layer is 47.0% or more. When the elastic power of the photosensitive layer is less than 47.0%, filming occurs on the photoreceptor. In the photoreceptor according to the first embodiment, since the charge transport layer is a single layer and is provided as the outermost surface layer, the elastic power of the photosensitive layer corresponds to the elastic power of the charge transport layer.

  In order to further improve the filming resistance of the photosensitive member, the elastic power of the photosensitive layer is preferably 50.0% or more. Further, the elastic power of the photosensitive layer is preferably 60.0% or less, and more preferably 55.0% or less.

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 relative humidity of 50% RH. It is measured by performing Step 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 mmN, and the maximum deformation work (EW ₁ : plastic deformation) when the load 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. To do. 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 (%) = [EW ₂ / EW ₁ ] × 100” is used. The elastic power of the photosensitive layer is obtained. The outline of the method for measuring the elastic power of the photosensitive layer has been described above. A method for measuring the elastic power of the photosensitive layer will be described in detail in Examples.

(Scratch depth of photosensitive layer)
The scratch depth of the photosensitive layer is preferably 0.50 μm or less. The photosensitive layer preferably has a hardness such that the scratch depth is 0.50 μm or less. When the scratch depth of the photosensitive layer is 0.50 μm or less, scratches on the surface of the photosensitive layer caused by contact with a member of the image forming apparatus (for example, a cleaning blade) during image formation can be suitably suppressed. As a result, toner components (for example, toner or external additives released from the toner) or minute components (for example, paper dust) of the recording medium enter the scratches on the surface of the photosensitive layer, and these components adhere to the surface of the photoreceptor. This can be suitably suppressed. As a result, the filming resistance of the photoreceptor can be further improved.

  In the photoreceptor according to the first embodiment, since the charge transport layer is a single layer and is provided as the outermost surface layer, the scratch depth of the photosensitive layer corresponds to the scratch depth of the charge transport layer. The charge transport layer contains at least the polyarylate resin (1), (2) or (3) as a binder resin and the additive (4), thereby adjusting the scratch depth of the photosensitive layer to 0.50 μm or less. it can.

  In order to further suppress the filming resistance of the photoreceptor, the scratch depth of the photosensitive layer is preferably 0.00 μm or more and 0.50 μm or less, and more preferably 0.20 μm or more and 0.45 μm or less. Preferably, it is 0.20 μm or more and 0.35 μm or less.

  The scratch depth of the photosensitive layer is measured by the following method. The scratch depth of the photosensitive layer is determined by using a scratch device defined in JIS K5600-5-5 in an environment of a temperature of 23 ° C. and a relative humidity of 50% RH. It is measured by performing the fourth step. The scratch device includes a fixed base and a scratch needle. The scratch needle has a hemispherical sapphire tip with a diameter of 1 mm. In the first step, the photosensitive member is fixed to the upper surface of the fixing base so that the longitudinal direction of the photosensitive member 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. In the third step, the photosensitive needle fixed to the fixing base and the upper surface of the fixing base is applied while applying a load of 10 g from the scratching needle to the photosensitive layer while the scratching needle is in contact with the surface of the photosensitive layer perpendicularly. The body is moved 30 mm at a speed of 30 mm / min in the longitudinal direction of the fixed base, and scratches are formed on the surface of the photosensitive layer by the scratching needle. In the fourth step, the scratch depth, which is the maximum depth of the scratch, is measured. The outline of the scratch depth measurement method has been described above. A method for measuring the scratch depth will be described in detail in Examples.

(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, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, trisazo pigments, indigo pigments, azurenium pigments, cyanine pigments, Powder of inorganic photoconductive material (more specifically, selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, amorphous silicon, etc.), pyrylium salt, ansanthrone pigment, triphenylmethane pigment, selenium pigment, toluidine Pigments, pyrazoline pigments or 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 or metal phthalocyanine. Metal-free phthalocyanine is represented by the chemical formula (CGM-1). Examples of metal phthalocyanines are titanyl phthalocyanine, hydroxygallium phthalocyanine or chlorogallium phthalocyanine. Titanyl phthalocyanine is represented by the chemical formula (CGM-2). The phthalocyanine pigment may be crystalline or non-crystalline. The crystal shape of the phthalocyanine pigment (for example, α-type, β-type, Y-type, V-type or II-type) is not particularly limited.

  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 crystal of titanyl phthalocyanine include α-type, β-type, and Y-type crystals of titanyl phthalocyanine (hereinafter, each may be referred to as α-type, β-type, or Y-type titanyl phthalocyanine).

  For example, in a digital optical image forming apparatus, it is preferable to use a photoconductor having sensitivity in a wavelength region of 700 nm or more. Examples of the digital optical image forming apparatus include a laser beam printer or a facsimile using a light source such as a semiconductor laser. The charge generation layer of the photoreceptor provided in such an image forming apparatus preferably contains a phthalocyanine pigment as a charge generation agent, more preferably contains a metal-free phthalocyanine or titanyl phthalocyanine, and an X type. More preferably, metal-free phthalocyanine or Y-type titanyl phthalocyanine is contained, more preferably Y-type titanyl phthalocyanine is contained, and particularly preferably only Y-type titanyl phthalocyanine is contained.

  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. 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. The Y-type titanyl phthalocyanine preferably has no peak at 26.2 ° C. in the CuKα characteristic X-ray diffraction spectrum.

  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 main peak is determined from the obtained X-ray diffraction spectrum, and the Bragg angle of the main peak is read.

  The charge generation layer of a photoreceptor applied to an image forming apparatus using a short wavelength laser light source (for example, a laser light source having a wavelength of 350 nm or more and 550 nm or less) contains an santhrone pigment as a charge generation agent. It is preferable.

  The content of the charge generating agent is preferably 0.1 parts by mass or more and 50 parts by mass or less, and 0.5 parts by mass or more and 30 parts by mass or less with respect to 1 part by mass of the base resin contained in the charge generation layer. It is more preferable that it is 0.5 mass part or more and 4.5 mass part or less. The content of the charge generating agent is preferably 0.1 parts by weight or more and 50 parts by weight or less, and 0.5 parts by weight or more and 30 parts by weight or less with respect to 100 parts by weight of the binder resin contained in the charge transport layer. The amount is more preferably 0.5 parts by mass or less and particularly preferably 0.5 parts by mass or more and 4.5 parts by mass or less.

(Binder resin)
The binder resin contains polyarylate resin (1), (2) or (3). Since the charge transport layer contains the polyarylate resin (1), (2) or (3) as the binder resin and the additive (4), the filming resistance of the photoreceptor is improved as described above. be able to. One of the polyarylate resins (1), (2) and (3) may be used alone, or two or more may be used in combination. Hereinafter, each of the polyarylate resins (1), (2), and (3) will be described.

(Polyarylate resin (1))
The polyarylate resin (1) is represented by the following general formula (1).

In the general formula (1), X ¹ and Y ¹ each represent a divalent group represented by the chemical formula (A), (B), (C), (D), (E) or (F). . X ¹ and Y ¹ are different from each other. kr and kt each independently represent 2 or 3. r ¹ and s ¹ each independently represent a positive number satisfying the mathematical expressions (1a) and (1b). t ¹ and u ¹ each independently represent a number of 0 or more that satisfies the mathematical expressions (1a) and (1b).
r ¹ + s ¹ + t ¹ + u ¹ = 100 (1a)
r ¹ + t ¹ = s ¹ + u ¹ (1b)

The polyarylate resin (1) has a repeating unit represented by the general formula (1-10) and a repeating unit represented by the general formula (1-11). When t ¹ and u ¹ represent a positive number, the polyarylate resin (1) includes a repeating unit represented by the general formula (1-12), a repeating unit represented by the general formula (1-13), and It has further. Hereinafter, the repeating units represented by the general formulas (1-10), (1-11), (1-12) and (1-13) are represented by repeating units (1-10) and (1-11), respectively. , (1-12) and (1-13).

Kr in the general formula (1-10), X ¹ in the general formula (1-11), kt in the general formula (1-12), and Y ¹ in the general formula (1-13) are respectively kr in the formula (1) have the same meanings as X ^1, kt and Y ^1.

In the general formula (1), r ¹ represents the number n _1-10 of the repeating unit ( _1-10 ) and the number n _1-11 of the repeating unit (1-11) contained in the polyarylate resin (1) and the repeating unit. to the sum of the number n _1-13 number n _1-12 repeating unit (1-13) of (1-12), representing a percentage of the number n _1-10 of repeat units (1-10). r ¹ is obtained from the formula “r ¹ = [n ₁₋₁₀ / (n ₁₋₁₀ + n ₁₋₁₁ + n ₁₋₁₂ + n ₁₋₁₃ )] × 100”. In the general formula (1), s ¹ represents the number n _1-10 of the repeating unit ( _1-10 ) and the number n _1-11 of the repeating unit (1-11) contained in the polyarylate resin (1) and the repeating unit. to the sum of the number n _1-13 number n _1-12 repeating unit (1-13) of (1-12), representing a percentage of the number n _1-11 of repeat units (1-11). s ¹ is obtained from the formula “s ¹ = [n _1-11 / (n _1-10 + n _1-11 + n _1-12 + n _1-13 )] × 100”. T ¹ in the general formula (1) is the number n _1-10 of the repeating unit ( _1-10 ), the number n _1-11 of the repeating unit (1-11) and the repeating unit contained in the polyarylate resin (1). to the sum of the number n _1-13 number n _1-12 repeating unit (1-13) of (1-12), representing a percentage of the number n _1-12 of repeat units (1-12). t ¹ is obtained from the formula “t ¹ = [n _1-12 / (n _1-10 + n _1-11 + n _1-12 + n _1-13 )] × 100”. U ¹ of the general formula (1), polyarylate resin number n _1-11 repeating unit number n _1-10 repeating unit of repeating units contained in the (1) (1-10) (1-11) It represents the percentage of the number n _1-13 of the repeating unit (1-13) to the sum of the number n _1-12 of (1-12) and the number n _1-13 of the repeating unit (1-13). u ¹ is obtained from the formula “u ¹ = [n _1-13 / (n _1-10 + n _1-11 + n _1-12 + n _1-13 )] × 100”.

Each of r ¹ , s ¹ , t ¹ and u ^{1 in} the general formula (1) is not a value obtained from one molecular chain, but the entire polyarylate resin (1) contained in the charge transport layer ( The average value of values obtained from a plurality of molecular chains. Each of r ¹ , s ¹ , t ¹ and u ¹ is measured, for example, by the following method. The ¹ H-NMR spectrum of the polyarylate resin (1) is measured using a proton nuclear magnetic resonance spectrometer. CDCl ₃ is used as a solvent, and tetramethylsilane (TMS) is used as an internal standard sample. In the ¹ H-NMR spectrum of the resulting polyarylate resin (1), a peak characteristic of the repeating unit (1-10), a peak characteristic of the repeating unit (1-11), a repeating unit (1- Each of r ¹ , s ¹ , t ¹ and u ¹ is calculated from the ratio of the peak characteristic to 12) and the peak characteristic to the repeating unit (1-13).

  The arrangement of the repeating units (1-10), (1-11), (1-12) and (1-13) in the polyarylate resin (1) is derived from the repeating unit derived from the aromatic diol and the aromatic dicarboxylic acid. There is no particular limitation as long as the repeating units are adjacent to each other. The repeating units derived from the aromatic diol are the repeating units (1-10) and (1-12). The repeating units derived from the aromatic dicarboxylic acid are the repeating units (1-11) and (1-13). For example, repeating units (1-10) and (1-12) are bonded to each other adjacent to repeating unit (1-11) or repeating unit (1-13).

The polyarylate resin (1) may further have a repeating unit other than the repeating units (1-10), (1-11), (1-12) and (1-13). The ratio of the total number of repeating units (1-10), (1-11), (1-12) and (1-13) to the total number of repeating units contained in the polyarylate resin (1) is 0.80. It is preferable that it is above, it is more preferable that it is 0.90 or more, and it is still more preferable that it is 1.00. When t ¹ and u ¹ are 0, the polyarylate resin (1) may have only the repeating units (1-10) and (1-11) as repeating units. In addition, when t ¹ and u ¹ are not 0, the polyarylate resin (1) has only repeating units (1-10), (1-11), (1-12) and (1-13) as repeating units. You may have.

  It is preferable that kr and kt in the general formula (1) each represent 3.

Hereinafter, a case where t ¹ and u ¹ in the general formula (1) are not 0 will be described. When t ¹ and u ¹ are not 0, the polyarylate resin (1) is preferably a polyarylate resin represented by the following general formula (1A), and the polyarylate resin represented by the following general formula (1B) It is more preferable that Hereinafter, the polyarylate resins represented by the general formulas (1A) and (1B) may be referred to as polyarylate resins (1A) and (1B), respectively.

X ^1, Y ^1, kr and kt in the general formula (1A), respectively, X ¹ in the general formula (1) in, Y ^1, the same meanings as kr and kt. X ¹ and Y ¹ in the general formula (1B), respectively, the same meanings as X ¹ and Y ¹ in formula (1). In the general formulas (1A) and (1B), r ¹¹ , s ¹¹ , t ¹¹ and u ¹¹ each independently represent a positive number satisfying the following mathematical formulas (1a ′), (1b ′) and (1c). .
r ¹¹ + s ¹¹ + t ¹¹ + u ¹¹ = 100 (1a ′)
r ¹¹ + t ¹¹ = s ¹¹ + u ¹¹ (1b ′)
0.30 ≦ s ¹¹ / (s ¹¹ + u ¹¹ ) ≦ 0.70 (1c)

In the general formulas (1A) and (1B), r ¹¹ , s ¹¹ , t ¹¹ and u ¹¹ are each independently represented by the following formula (1d) in addition to the formulas (1a ′), (1b ′) and (1c): ) May further be expressed as a positive number.
0.30 ≦ r ¹¹ / (r ¹¹ + t ¹¹ ) ≦ 0.70 (1d)

“S ¹¹ / (s ¹¹ + u ¹¹ )” represented by the mathematical formula (1c) is preferably 0.40 or more and 0.60 or less, and more preferably 0.50. “R ¹¹ / (r ¹¹ + t ¹¹ )” represented by the mathematical formula (1d) is preferably 0.40 or more and 0.60 or less, and more preferably 0.50.

The polyarylate resin (1B) includes a repeating unit represented by the chemical formula (1B-10), a repeating unit represented by the general formula (1B-11), and a repeating unit represented by the general formula (1B-13). . X ¹ in the general formula (1B-11) and Y ¹ in the general formula (1B-13) are respectively synonymous with X ¹ and Y ¹ in the general formula (1). Hereinafter, the repeating unit represented by the chemical formula (1B-10), the repeating unit represented by the general formula (1B-11), and the general formula (1B-13) are respectively represented by the repeating units (1B-10) and (1B -11) and (1B-13).

In polyarylate resin (1B), the number n _1B-13 of the repeating unit number n _1B-11 and repeating units (1B-10) number n _1B-10 and repeating units of (1B-11) (1B- 13) The percentage “[n _1B-10 / (n _1B-10 + n _1B-11 + n _1B-13 )] × 100” of the number n _1B-10 of the repeating units (1B-10) with respect to the sum of is 50. Repeat unit (1B-) for the sum of the number n _1B-10 of repeat units (1B-10), the number _1B-11 of repeat units (1B- ₁₁ ) and the number n _{1B-13 of} repeat units (1B-13) 11) Percentage of the sum of the number _1B-11 of the repeating unit and the number n _1B-13 of the repeating unit (1B-13) “[(n _1B-11 + n _1B-13 ) / (n _1B-10 + n _1B-11 + n _{1B −13} )] × 100 ”is 50. Repeating unit (1B-11) to the sum of the number n _1B-13 number _1B-11 and the repeating unit (1B-13) of the repeating unit (1B-11) number _1B-11 ratio of the "n _1B-11 / (N _1B-11 + n _1B-13 ) ”is preferably 0.30 or more and 0.70 or less, more preferably 0.40 or more and 0.60 or less, and more preferably 0.50. Particularly preferred.

When t ¹ and u ¹ in the general formula (1) are not 0, in order to improve the filming resistance of the photoreceptor, the polyarylate resin (1) has the general formulas (1-1), (1- It is preferable that it is a polyarylate resin represented by 2), (1-3) or (1-4). In formulas (1-1), (1-2), (1-3) and (1-4), r ¹¹ , s ¹¹ , t ¹¹ and u ¹¹ are the same in formulas (1A) and (1B). Are the same as r ¹¹ , s ¹¹ , t ¹¹ and u ^{11 in} Hereinafter, the polyarylate resins represented by the general formulas (1-1), (1-2), (1-3) and (1-4) are respectively represented by polyarylate resins (1-1), (1- 2), (1-3) and (1-4). A more preferred example of the polyarylate resin (1) is the polyarylate resin (1-1). Another more preferable example of the polyarylate resin (1) is the polyarylate resin (1-2).

The polyarylate resin (1-1) is represented by the repeating unit represented by the chemical formula (1-1-10), the repeating unit represented by the chemical formula (1-1-11), and the chemical formula (1-1-13). Containing repeating units. Number of repeating units n _1-1-10 represented by chemical formula (1-1-10) in polyarylate resin (1-1), number n _{1 of} repeating units represented by chemical formula (1-1-11) _-1-11 and the number of repeating units n _1-1-13 represented by the chemical formula (1-1-13) are based on the number of repeating units (1B-10) in the polyarylate resin (1B) n _{1B- 10} , the number n _1B-11 of the repeating unit (1B- ₁₁ ) and the number n _1B-13 of the repeating unit (1B-13) are the same.

The polyarylate resin (1-2) is represented by the repeating unit represented by the chemical formula (1-2-10), the repeating unit represented by the chemical formula (1-2-11), and the chemical formula (1-2-13). Containing repeating units. The number of repeating units n _1-2-10 represented by the chemical formula (1-2-10) in the polyarylate resin (1-2) and the number n _{1 of} repeating units represented by the chemical formula (1-2-11) _-2-11 and the number of repeating units represented by the chemical formula (1-2-13) n _1-2-13 is related to the number of repeating units (1B-10) in the polyarylate resin (1B) n _{1B- 10} , the number n _1B-11 of the repeating unit (1B- ₁₁ ) and the number n _1B-13 of the repeating unit (1B-13) are the same.

The polyarylate resin (1-3) is represented by the repeating unit represented by the chemical formula (1-3-10), the repeating unit represented by the chemical formula (1-3-11), and the chemical formula (1-3-13). Containing repeating units. Number of repeating units n _1-3-10 represented by chemical formula (1-3-10) in polyarylate resin (1-3), number n _{1 of} repeating units represented by chemical formula (1-3-11) The number n _1-3-13 of repeating units represented by _-3-11 and the chemical formula (1-3-13) is related to the number n _1B- of repeating units (1B-10) in the polyarylate resin (1B). ₁₀ , the number n _1B-11 of the repeating unit (1B- ₁₁ ) and the number n _1B-13 of the repeating unit (1B-13) are the same.

The polyarylate resin (1-4) is represented by the repeating unit represented by the chemical formula (1-4-10), the repeating unit represented by the chemical formula (1-4-11), and the chemical formula (1-4-13). Containing repeating units. Number of repeating units n _1-4-10 represented by chemical formula (1-4-10) in polyarylate resin (1-4), number n _{1 of} repeating units represented by chemical formula (1-4-11) _-4-11 and the number of repeating units represented by the chemical formula (1-4-13) n _1-4-13 are related to the number of repeating units (1B-10) in the polyarylate resin (1B) n _{1B- 10} , the number n _1B-11 of the repeating unit (1B- ₁₁ ) and the number n _1B-13 of the repeating unit (1B-13) are the same.

Hereinafter, the case where t ¹ and u ¹ in the general formula (1) are 0 will be described. When t ¹ and u ¹ are 0, r ¹ and s ¹ in the general formula (1) each represents 50. The polyarylate resin (1) when t ¹ and u ¹ are 0 is preferably a polyarylate resin represented by the following general formula (1C), and the polyarylate represented by the following general formula (1D) More preferably, it is a resin. Hereinafter, the polyarylate resins represented by the general formulas (1C) and (1D) may be referred to as polyarylate resins (1C) and (1D), respectively.

X ¹ and kr in the formula (1C), respectively, the same meanings as X ¹ and kr in the formula (1). X ¹ in the general formula (1D), respectively, the same meaning as X ¹ in the general formula (1).

The polyarylate resin (1D) includes a repeating unit represented by the chemical formula (1D-10) and a repeating unit represented by the general formula (1D-11). X ¹ in the general formula (1D-11), respectively, the same meaning as X ¹ in the general formula (1). Hereinafter, the repeating unit represented by the chemical formula (1D-10) and the repeating unit represented by the general formula (1D-11) may be referred to as the repeating unit (1D-10) and (1D-11), respectively. is there.

In polyarylate resin (1D), to the sum of the number n _1D-11 number n _1D-10 and repeating units of the repeating unit (1D-10) (1D- 11), the number n of the repeating units (1D-10) The percentage of _1D-10 “[n _1D-10 / (n _1D-10 + n _1D-11 )] × 100” is 50. Percentage of the number n _1D-11 of repeating units (1D-11) to the sum of the number n _1D-10 of repeating units (1D-10) and the number n _{1D-11 of} repeating units (1D-11) “[n _1D-11 / (n _1D-10 + n _1D-11 )] × 100 ”is 50.

When t ¹ and u ¹ in the general formula (1) are 0, in order to improve the filming resistance of the photoreceptor, the polyarylate resin (1) is represented by the chemical formula (1-5) or (1- The polyarylate resin represented by 6) is preferable.

  The viscosity average molecular weight of the polyarylate resin (1) is preferably 35000 or more, more preferably 40000 or more, and further preferably 45000 or more. When the viscosity average molecular weight of the polyarylate resin (1) is 35000 or more, the charge transport layer is hardly worn. On the other hand, the viscosity average molecular weight of the polyarylate resin (1) is preferably 75000 or less, more preferably 60000 or less, and further preferably 55000 or less. When the viscosity average molecular weight of the polyarylate resin (1) is 75000 or less, the polyarylate resin (1) is easily dissolved in the solvent for forming the charge transport layer, and the charge transport layer is easily formed.

(Polyarylate resin (2))
The polyarylate resin (2) is represented by the following general formula (2).

In the general formula (2), R ²¹ , R ²² , R ²³ and R ²⁴ each independently represents a hydrogen atom or a methyl group. X ² and Y ² each represent a divalent group represented by the chemical formula (A), (B), (C), (D), (E) or (F). The divalent groups represented by the chemical formula (A), (B), (C), (D), (E) or (F) in the general formula (2) are each in the general formula (1). This is the same as the divalent group represented by the chemical formula (A), (B), (C), (D), (E) or (F). X ² and Y ² are different from each other. r ² , s ² , t ² and u ² each independently represent a positive number satisfying the following mathematical formulas (2a), (2b) and (2c).
r ² + s ² + t ² + u ² = 100 (2a)
r ² + t ² = s ² + u ² (2b)
0.30 ≦ s ² / (s ² + u ² ) ≦ 0.70 (2c)

r ² , s ² , t ^2, and u ² may each independently represent a positive number that further satisfies the following formula (2d) in addition to the formulas (2a), (2b), and (2c).
0.30 ≦ r ² / (r ² + t ² ) ≦ 0.70 (2d)

In order to further improve the filming resistance of the photoreceptor, it is preferable that R ²¹ , R ²² , R ²³ and R ²⁴ in the general formula (2) each represent a methyl group. For the same reason, one of X ² and Y ² represents a divalent group represented by the chemical formula (C), and the other of X ² and Y ² represents a divalent group represented by the chemical formula (E). Is preferred.

r ² and s ² may be different from each other. r ² and u ² may be different from each other. t ² and s ² may be different from each other. t ² and u ² may be different from each other.

  The polyarylate resin (2) includes a repeating unit represented by the general formula (2-10), a repeating unit represented by the general formula (2-11), and a repeating unit represented by the general formula (2-12). A unit and a repeating unit represented by formula (2-13). Hereinafter, the repeating units represented by the general formulas (2-10), (2-11), (2-12) and (2-13) are represented by repeating units (2-10) and (2-11), respectively. , (2-12) and (2-13).

R ²¹ and R ²² in general formula (2-10), X ² in general formula (2-11), R ²³ and R ^{24 in} general formula (2-12), and general formula (2-13) Y ² in each has the same meaning as R ²¹ , R ²² , X ² , R ²³ , R ²⁴ and Y ^{2 in} formula (2).

In the general formula (2), r ² represents the number n _2-10 of the repeating unit ( _2-10 ) and the number n _2-11 of the repeating unit (2-11) contained in the polyarylate resin (2) and the repeating unit. to the sum of the number n _2-13 number n _2-12 repeating unit (2-13) of (2-12), representing a percentage of the number n _2-10 of repeat units (2-10). r ² is obtained from the formula “r ² = [n ₂₋₁₀ / (n ₂₋₁₀ + n ₂₋₁₁ + n ₂₋₁₂ + n ₂₋₁₃ )] × 100”. In the general formula (2), s ² represents the number n _2-10 of the repeating unit ( _2-10 ), the number n _2-11 of the repeating unit (2-11) and the repeating unit contained in the polyarylate resin (2). to the sum of the number n _2-13 number n _2-12 repeating unit (2-13) of (2-12), representing a percentage of the number n _2-11 of repeat units (2-11). s ² is obtained from the formula “s ² = [n _2-11 / (n _2-10 + n _2-11 + n _2-12 + n _2-13 )] × 100”. T ² in the general formula (2) represents the number n _2-10 of the repeating unit ( _2-10 ), the number n _2-11 of the repeating unit (2-11) and the repeating unit contained in the polyarylate resin (2). to the sum of the number n _2-13 number n _2-12 repeating unit (2-13) of (2-12), representing a percentage of the number n _2-12 of repeat units (2-12). t ² is obtained from the equation “t ² = [n _2-12 / (n _2-10 + n _2-11 + n _2-12 + n _2-13 )] × 100”. In the general formula (2), u ² represents the number n _2-10 of the repeating unit ( _2-10 ), the number n _2-11 of the repeating unit (2-11) and the repeating unit contained in the polyarylate resin (2). The percentage of the number n _2-13 of the repeating unit (2-13) to the sum of the number n _2-12 of (2-12) and the number n _2-13 of the repeating unit (2-13) is represented. u ² is obtained from the formula “u ² = [n ² ₋₁₃ / (n 2 ₋₁₀ + n 2 ₋₁₁ + n 2 ₋₁₂ + n 2 ₋₁₃ )] × 100”.

Each of r ² , s ² , t ² and u ^{2 in} the general formula (2) is not a value obtained from one molecular chain, but the entire polyarylate resin (2) contained in the charge transport layer ( The average value of values obtained from a plurality of molecular chains. Each of r ² , s ² , t ² and u ² is measured, for example, by the following method. Using a proton nuclear magnetic resonance spectrometer, the ¹ H-NMR spectrum of the polyarylate resin (2) is measured. CDCl ₃ is used as a solvent, and tetramethylsilane (TMS) is used as an internal standard sample. In the ¹ H-NMR spectrum of the obtained polyarylate resin (2), a peak characteristic of the repeating unit (2-10), a peak characteristic of the repeating unit (2-11), a repeating unit (2- Each of r ² , s ² , t ² and u ² is calculated from the ratio of the peak characteristic to 12) and the peak characteristic to the repeating unit (2-13).

  The sequence of the repeating units (2-10), (2-11), (2-12) and (2-13) in the polyarylate resin (2) is derived from the repeating unit derived from the aromatic diol and the aromatic dicarboxylic acid. There is no particular limitation as long as the repeating units are adjacent to each other. The repeating units derived from the aromatic diol are the repeating units (2-10) and (2-12). The repeating units derived from the aromatic dicarboxylic acid are the repeating units (2-11) and (2-13). For example, the repeating units (2-10) and (2-12) are adjacent to each other and bonded to the repeating unit (2-11) or the repeating unit (2-13).

  The polyarylate resin (2) may further have a repeating unit other than the repeating units (2-10), (2-11), (2-12) and (2-13). The ratio of the total number of repeating units (2-10), (2-11), (2-12) and (2-13) to the total number of repeating units contained in the polyarylate resin (2) is 0.80. It is preferable that it is above, more preferably 0.90 or more, and still more preferably 1.00. The polyarylate resin (2) may have only the repeating units (2-10), (2-11), (2-12) and (2-13) as repeating units.

“S ² / (s ² + u ² )” represented by the mathematical formula (2c) is preferably 0.40 or more and 0.60 or less, and more preferably 0.50. “R ² / (r ² + t ² )” represented by the mathematical formula (2d) is preferably 0.40 or more and 0.60 or less, and more preferably 0.50.

In order to improve the filming resistance of the photoreceptor, the polyarylate resin (2) is described as a polyarylate resin represented by the general formula (2-1) (hereinafter referred to as polyarylate resin (2-1)). It is preferable that R ^2, s ^2, t ² and u ² in the general formula (2-1) are each a r of the general formula (2) in ^2, s ^2, synonymous with t ² and u ^2.

  The polyarylate resin (2-1) is represented by the repeating unit represented by the chemical formula (2-1-10), the repeating unit represented by the chemical formula (2-1-11), and the chemical formula (2-1-13). Containing repeating units.

In polyarylate resin (2-1), the number n _2-1-11 repeating unit number n _2-1-10 repeating unit of the repeating unit (2-1-10) (2-1-11) (2 -1-13) The percentage of the number n _2-1-10 of the repeating unit (2-1-10) to the sum of the number n _2-1-13 and the number n _2-1-13 [[n _2-1-10 / (n _{2− 1-10} + n _2-1-11 + n _2-1-13 )] × 100 "is 50. Number n _2-1-10 of repeating unit ( _2-1-10 ), number _2-1-11 of repeating unit ( _2-1-11 ), and number n _2-1 of repeating unit (2-1-13) The percentage of the sum of the number _2-1-11 of the repeating unit ( _2-1-11 ) and the number n _2-1-13 of the repeating unit (2-1-13) with respect to the sum of _-13 “[(n _2-1-11 + n _2-1-13 ) / (n _2-1-10 + n _2-1-11 + n _2-1-13 )] × 100 ”is 50. To the sum of the number n _2-1-13 number _2-1-11 repeating unit (2-1-13) of the repeating unit (2-1-11), the number of repeating units (2-1-11) the ratio of _{2-1-11 'n 2-1-11 / (n 2-1-11 + n} 2-1-13) "is preferably 0.30 to 0.70, 0.40 or higher It is more preferably 0.60 or less, and particularly preferably 0.50.

  The viscosity average molecular weight of the polyarylate resin (2) is preferably 35000 or more, more preferably 40000 or more, and further preferably 45000 or more. When the viscosity average molecular weight of the polyarylate resin (2) is 35000 or more, the charge transport layer is hardly worn. On the other hand, the viscosity average molecular weight of the polyarylate resin (2) is preferably 75000 or less, more preferably 60000 or less, and further preferably 55000 or less. When the viscosity average molecular weight of the polyarylate resin (2) is 75000 or less, the polyarylate resin (2) is easily dissolved in the solvent for forming the charge transport layer, and the charge transport layer is easily formed.

(Polyarylate resin (3))
The polyarylate resin (3) is represented by the following general formula (3).

In general formula (3), R ³¹ , R ³² , R ³³ and R ³⁴ each independently represents a hydrogen atom or a methyl group. X ³ and Y ³ each represent a divalent group represented by the chemical formula (A), (B), (C), (D), (E) or (F). The divalent groups represented by the chemical formula (A), (B), (C), (D), (E) or (F) in the general formula (3) are each in the general formula (1). This is the same as the divalent group represented by the chemical formula (A), (B), (C), (D), (E) or (F). X ³ and Y ³ are different from each other. r ³ , s ³ , t ³ and u ³ each independently represent a positive number satisfying the following mathematical formulas (3a), (3b) and (3c).
r ³ + s ³ + t ³ + u ³ = 100 (3a)
r ³ + t ³ = s ³ + u ³ (3b)
0.30 ≦ s ³ / (s ³ + u ³ ) ≦ 0.70 (3c)

r ³ , s ³ , t ^3, and u ³ may each independently represent a positive number that further satisfies the following formula (3d) in addition to the formulas (3a), (3b), and (3c).
0.30 ≦ r ³ / (r ³ + t ³ ) ≦ 0.70 (3d)

In order to further improve the filming resistance of the photoreceptor, it is preferable that R ³¹ , R ³² , R ^33, and R ³⁴ in the general formula (3) each represent a hydrogen atom. For the same reason, one of X ³ and Y ³ represents a divalent group represented by the chemical formula (C), and the other of X ³ and Y ³ represents a divalent group represented by the chemical formula (E). Is preferred.

r ³ and s ³ may be different from each other. r ³ and u ³ may be different from each other. t ³ and s ³ may be different from each other. t ³ and u ³ may be different from each other.

  The polyarylate resin (3) includes a repeating unit represented by the general formula (3-10), a repeating unit represented by the general formula (3-11), and a repeating unit represented by the general formula (3-12). A unit and a repeating unit represented by formula (3-13). Hereinafter, the repeating units represented by the general formulas (3-10), (3-11), (3-12) and (3-13) are represented by repeating units (3-10) and (3-11), respectively. , (3-12) and (3-13).

R ³¹ and R ³² in general formula (3-10), X ³ in general formula (3-11), R ³³ and R ^{34 in} general formula (3-12), and general formula (3-13) Y ³ in each has the same meaning as R ³¹ , R ³² , X ³ , R ³³ , R ³⁴ and Y ^{3 in} the general formula (3).

R ³ of the general formula (3), polyarylate resins number n _3-11 repeating unit number n _3-10 repeating unit (3-11) of the repeating units (3-10) included in (3) to the sum of the number n _3-13 number n _3-12 repeating unit (3-13) of (3-12), representing a percentage of the number n _3-10 of repeat units (3-10). r ³ is obtained from the mathematical expression “r ³ = [n _3-10 / (n _3-10 + n _3-11 + n _3-12 + n _3-13 )] × 100”. In the general formula (3), s ³ represents the number n _3-10 of the repeating unit ( _3-10 ) and the number n _3-11 of the repeating unit (3-11) contained in the polyarylate resin (3). to the sum of the number n _3-13 number n _3-12 repeating unit (3-13) of (3-12), representing a percentage of the number n _3-11 of repeat units (3-11). The s ³ is obtained from the formula “s ³ = [n _3-11 / (n _3-10 + n _3-11 + n _3-12 + n _3-13 )] × 100”. T ³ in the general formula (3) represents the number n _3-10 of the repeating unit ( _3-10 ), the number n _3-11 of the repeating unit (3-11) and the repeating unit contained in the polyarylate resin (3). to the sum of the number n _3-13 number n _3-12 repeating unit (3-13) of (3-12), representing a percentage of the number n _3-12 of repeat units (3-12). t ³ is obtained from the equation “t ³ = [n ₃₋₁₂ / (n ₃₋₁₀ + n ₃₋₁₁ + n ₃₋₁₂ + n ₃₋₁₃ )] × 100”. U ³ of the general formula (3), polyarylate resins number n _3-11 repeating unit number n _3-10 repeating unit (3-11) of the repeating units (3-10) included in (3) to the sum of the number n _3-13 number n _3-12 repeating unit (3-13) of (3-12), representing a percentage of the number n _3-13 of repeat units (3-13). u ³ is obtained from the formula “u ³ = [n _3-13 / (n _3-10 + n _3-11 + n _3-12 + n _3-13 )] × 100”.

Each of r ³ , s ³ , t ³ and u ^{3 in} the general formula (3) is not a value obtained from one molecular chain, but the entire polyarylate resin (3) contained in the charge transport layer ( The average value of values obtained from a plurality of molecular chains. Each of r ³ , s ³ , t ³ and u ³ is measured, for example, by the following method. Using a proton nuclear magnetic resonance spectrometer, the ¹ H-NMR spectrum of the polyarylate resin (3) is measured. CDCl ₃ is used as a solvent, and tetramethylsilane (TMS) is used as an internal standard sample. In the ¹ H-NMR spectrum of the resulting polyarylate resin (3), a peak characteristic of the repeating unit (3-10), a peak characteristic of the repeating unit (3-11), a repeating unit (3- Each of r ³ , s ³ , t ³ and u ³ is calculated from the ratio of the peak characteristic to 12) and the peak characteristic to the repeating unit (3-13).

  The sequences of the repeating units (3-10), (3-11), (3-12) and (3-13) in the polyarylate resin (3) are derived from the repeating units derived from the aromatic diol and the aromatic dicarboxylic acid. There is no particular limitation as long as the repeating units are adjacent to each other. The repeating units derived from the aromatic diol are the repeating units (3-10) and (3-12). The repeating units derived from the aromatic dicarboxylic acid are the repeating units (3-11) and (3-13). For example, the repeating units (3-10) and (3-12) are bonded to each other adjacent to the repeating unit (3-11) or the repeating unit (3-13).

  The polyarylate resin (3) may further have a repeating unit other than the repeating units (3-10), (3-11), (3-12) and (3-13). The ratio of the total number of repeating units (3-10), (3-11), (3-12) and (3-13) to the total number of repeating units contained in the polyarylate resin (3) is 0.80. It is preferable that it is above, more preferably 0.90 or more, and still more preferably 1.00. The polyarylate resin (3) may have only the repeating units (3-10), (3-11), (3-12) and (3-13) as repeating units.

“S ³ / (s ³ + u ³ )” represented by the mathematical formula (3c) is preferably 0.40 or more and 0.60 or less, and more preferably 0.50. “R ³ / (r ³ + t ³ )” represented by the mathematical formula (3d) is preferably 0.40 or more and 0.60 or less, and more preferably 0.50.

In order to improve the filming resistance of the photoreceptor, the polyarylate resin (3) is described as a polyarylate resin represented by the general formula (3-1) (hereinafter referred to as polyarylate resin (3-1)). It is preferable that General r ³ of formula (3-1) in, s ^3, t ³ and u ³ are each the same meaning as in formula (3) in the r ^3, s ^3, t ^3, and u ^3.

  The polyarylate resin (3-1) is represented by the repeating unit represented by the chemical formula (3-1-10), the repeating unit represented by the chemical formula (3-1-11), and the chemical formula (3-1-13). Containing repeating units.

In polyarylate resin (3-1), the number n _3-1-11 repeating unit number n _3-1-10 repeating unit of the repeating unit (3-1-10) (3-1-11) (3 -1-13) The percentage of the number n _3-1-10 of the repeating unit (3-1-10) to the sum of the number n _3-1-13 and [n _3-1-10 / (n _{3- 1-10} + n _3-1-11 + n _3-1-13 )] × 100 ”is 50. Number n _3-1-10 of repeating unit ( _3-1-10 ), number _3-1-11 of repeating unit ( _3-1-11 ), and number n _3-1 of repeating unit (3-1-13) _{% Of} the sum of the number of repeating units (3-1-11) _3-1-11 and the number of repeating units (3-1-13) n _3-1-13 with respect to the sum of _-13 “[(n _3-1-11 + _n3-1-13 ) / ( _n3-1-10 + _n3-1-11 + _n3-1-13 )] × 100 ”is 50. Number of repeating units (3-1-11) with respect to the sum of number of repeating units (3-1-11) _3-1-11 and number of repeating units (3-1-13) n _3-1-13 the ratio of _{3-1-11 'n 3-1-11 / (n 3-1-11 + n} 3-1-13) "is preferably 0.30 to 0.70, 0.40 or higher It is more preferably 0.60 or less, and particularly preferably 0.50.

  Of the polyarylate resins (1-1) to (1-6), (2-1), and (3-1), the polyarylate resin (1-1) is preferable. Of the polyarylate resins (1-1) to (1-6), (2-1), and (3-1), from the viewpoint of further improving the filming resistance of the photoreceptor, the polyarylate resin (2-1) ) Is preferred.

  The viscosity average molecular weight of the polyarylate resin (3) is preferably 35000 or more, more preferably 40000 or more, and further preferably 45000 or more. When the viscosity average molecular weight of the polyarylate resin (3) is 35000 or more, the charge transport layer is hardly worn. On the other hand, the viscosity average molecular weight of the polyarylate resin (3) is preferably 75000 or less, more preferably 60000 or less, and further preferably 55000 or less. When the viscosity average molecular weight of the polyarylate resin (3) is 75000 or less, the polyarylate resin (3) is easily dissolved in the solvent for forming the charge transport layer, and the charge transport layer is easily formed.

  The charge transport layer may contain only the polyarylate resin (1), (2) or (3) as the binder resin. Alternatively, the charge transport layer may be used as a binder resin in addition to the polyarylate resin (1), (2) or (3), or a resin other than the polyarylate resins (1), (2) and (3) ) May be included. Examples of other resins include thermoplastic resins (specifically, polyarylate resins other than polyarylate resins (1), (2) and (3), polycarbonate resins, styrene resins, and styrene-butadiene copolymers. , Styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, 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 or polyester resin), thermosetting Resin Specifically, silicone resin, epoxy resin, phenol resin, urea resin, melamine resin or other cross-linkable thermosetting resin) or photo-curing resin (specifically, epoxy-acrylic resin or urethane-acrylic acid) Type copolymer). Other resin may be used independently and may use 2 or more types together.

(Production method of polyarylate resin (1), (2) and (3))
The manufacturing method of polyarylate resin (1) is not specifically limited. The production method of the polyarylate resin (1) when t ¹ and u ¹ in the general formula (1) are 0 is, for example, a first aromatic diol represented by the general formula (BP-A), A polyarylate resin (1) is obtained by condensation polymerization of the first aromatic dicarboxylic acid represented by the formula (DC-A). The production method of the polyarylate resin (1) when t ¹ and u ¹ in the general formula (1) are not 0 is, for example, the first aromatic diol represented by the general formula (BP-A) and the general formula The second aromatic diol represented by (BP-B), the first aromatic dicarboxylic acid represented by the general formula (DC-A), and the second aromatic diol represented by the general formula (DC-B). Polyarylate resin (1) is obtained by condensation polymerization with dicarboxylic acid. Kr in the general formula (BP-A), kt in the general formula (BP-B), X ¹ in the general formula (DC-A), and Y ¹ in the general formula (DC-B) are each represented by: It is synonymous with kr, kt, X ¹ and Y ^{1 in the} general formula (1).

The manufacturing method of polyarylate resin (2) is not specifically limited. The production method of the polyarylate resin (2) includes, for example, a first aromatic diol represented by the general formula (BP-C), a second aromatic diol represented by the general formula (BP-D), A polyarylate resin (2) is obtained by polycondensing a first aromatic dicarboxylic acid represented by the formula (DC-C) and a second aromatic dicarboxylic acid represented by the general formula (DC-D). . R ²¹ and R ^{22 in} the general formula (BP-C), R ²³ and R ²⁴ in the general formula (BP-D), X ² in the general formula (DC-C) and the general formula (DC-D) Y ² in each has the same meaning as R ²¹ , R ²² , R ²³ , R ²⁴ , X ² and Y ^{2 in} the general formula (2).

The manufacturing method of polyarylate resin (3) is not specifically limited. The production method of the polyarylate resin (3) includes, for example, a first aromatic diol represented by the general formula (BP-E), a second aromatic diol represented by the general formula (BP-F), A polyarylate resin (3) is obtained by polycondensing a first aromatic dicarboxylic acid represented by the formula (DC-E) and a second aromatic dicarboxylic acid represented by the general formula (DC-F). . R ³¹ and R ^{32 in} the general formula (BP-E), R ³³ and R ³⁴ in the general formula (BP-F), X ³ in the general formula (DC-E) and the general formula (DC-F) Y ³ in each has the same meaning as R ³¹ , R ³² , R ³³ , R ³⁴ , X ³ and Y ^{3 in} the general formula (3).

  Each of the aromatic diols represented by the general formulas (BP-A) to (BP-F) (hereinafter sometimes referred to as compounds (BP-A) to (BP-F)) is derivatized. May be used. An example of a derivative of an aromatic diol is an aromatic diacetate.

  Each of the aromatic dicarboxylic acids represented by the general formulas (DC-A) to (DC-F) (hereinafter sometimes referred to as compounds (DC-A) to (DC-F)) is a derivative. May be used. Examples of derivatives of aromatic dicarboxylic acids are aromatic dicarboxylic acid dichloride, aromatic dicarboxylic acid dimethyl ester, aromatic dicarboxylic acid diethyl ester or aromatic dicarboxylic acid anhydride. An aromatic dicarboxylic acid dichloride is a compound in which two “—C (═O) —OH” groups of an aromatic dicarboxylic acid are each substituted with a “—C (═O) —Cl” group.

  As a method for polycondensing an aromatic diol and an aromatic dicarboxylic acid, a known synthesis method (more specifically, solution polymerization, melt polymerization, interfacial polymerization, or the like) can be employed. The polycondensation reaction may proceed in the presence of an alkali and a catalyst. Examples of the catalyst include tertiary ammonium (more specifically, trialkylamine and the like) or quaternary ammonium salt (more specifically, benzyltrimethylammonium bromide and the like). Examples of the alkali include an alkali metal hydroxide (more specifically, sodium hydroxide or potassium hydroxide) or an alkaline earth metal hydroxide (more specifically, calcium hydroxide). Can be mentioned. The polycondensation reaction may proceed in a solvent and under an inert gas atmosphere. Examples of the solvent include water or chloroform. Examples of the inert gas include argon. The reaction time of the polycondensation reaction is preferably 2 hours or more and 5 hours or less. The reaction temperature of the polycondensation reaction is preferably 5 ° C. or more and 25 ° C. or less. If necessary, the polyarylate resin (1), (2) or (3) may be purified after the polycondensation reaction. Examples of the purification method include known methods (more specifically, filtration, chromatography, crystal folding, etc.).

  Preferable examples of the compounds (DC-A) to (DC-F) are compounds represented by chemical formulas (DC-1) to (DC-6). Hereinafter, the compounds represented by chemical formulas (DC-1) to (DC-6) may be referred to as compounds (DC-1) to (DC-6), respectively. As the compound (DC-A), a compound different from the compound (DC-B) is selected. As the compound (DC-C), a compound different from the compound (DC-D) is selected. A compound different from the compound (DC-F) is selected as the compound (DC-E).

  A preferable example of each of the compounds (BP-A) and (BP-B) is a compound represented by the chemical formula (BP-1) or (BP-2). Hereinafter, the compounds represented by the chemical formulas (BP-1) and (BP-2) may be referred to as compounds (BP-1) and (BP-2), respectively.

  A suitable example of each of the compounds (BP-C) and (BP-D) is a compound represented by the chemical formula (BP-3), (BP-4) or (BP-5). Hereinafter, the compounds represented by the chemical formulas (BP-3), (BP-4), and (BP-5) are referred to as compounds (BP-3), (BP-4), and (BP-5), respectively. Sometimes.

  Preferable examples of the compounds (BP-E) and (BP-F) are compounds represented by the chemical formula (BP-7), (BP-8) or (BP-9). Hereinafter, the compounds represented by the chemical formulas (BP-7), (BP-8), and (BP-9) are referred to as compounds (BP-7), (BP-8), and (BP-9), respectively. Sometimes.

(Hole transport agent)
Examples of the hole transporting agent include triphenylamine derivatives and diamine derivatives (more specifically, N, N, N ′, N′-tetraphenylbenzidine derivatives, N, N, N ′, N′-tetraphenyl). Phenylenediamine derivatives, N, N, N ′, N′-tetraphenylnaphthylenediamine derivatives, N, N, N ′, N′-tetraphenylphenanthrylenediamine derivatives or di (aminophenylethenyl) benzene derivatives, etc.) Oxadiazole compounds (more specifically, 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole, etc.), styryl compounds (more specifically, 9- (4-diethylaminostyryl) anthracene, etc.), carbazole compounds (more specifically, polyvinyl carbazole, etc.), organic polysilane compounds, pyrazoline compounds Compound (more specifically, 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline etc.), hydrazone compound, indole compound, oxazole compound, isoxazole compound, thiazole compound, thiadiazole compound , An imidazole compound, a pyrazole compound, or a triazole compound. A hole transport agent may be used individually by 1 type, and may be used in combination of 2 or more type.

  Of these hole transporting agents, compounds represented by the general formula (10) or (11) are preferable. Hereinafter, the compounds represented by general formula (10) or (11) may be referred to as compounds (10) and (11), respectively.

  Compound (10) is represented by the following general formula (10).

In the general formula (10), R ¹⁰¹ , R ¹⁰² , R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ and R ¹⁰⁶ are each independently an alkyl group having 1 to 8 carbon atoms, a phenyl group, or 1 to 8 carbon atoms. The following alkoxy groups are represented. k, l, m and n each independently represent an integer of 0 or more and 5 or less. p and q each independently represent an integer of 0 or more and 4 or less.

In general formula (10), the alkyl group having 1 to 8 carbon atoms represented by R ^{101 to} R ¹⁰⁶ is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group.

In the general formula (10), R ¹⁰¹ , R ¹⁰² , R ¹⁰³ and R ¹⁰⁴ represent an alkyl group having 1 to 3 carbon atoms, k, l, m and n represent 1, and p and q are 0. Is preferably represented.

  Preferable examples of compound (10) include a compound represented by chemical formula (10-1) (hereinafter sometimes referred to as compound (10-1)).

  The compound (11) is represented by the following general formula (11).

In general formula (11), R ¹¹¹ , R ¹¹² , R ¹¹³ , R ¹¹⁴ , R ¹¹⁵ and R ¹¹⁶ are each independently a halogen atom or an alkyl having 1 to 6 carbon atoms which may have a substituent. Represents an alkoxy group having 1 to 6 carbon atoms which may have a group or a substituent, or an aryl group having 6 to 14 carbon atoms which may have a substituent. a represents an integer of 1 to 3. d, e, f, g, h, and i each independently represent an integer of 0 to 5, and when d represents an integer of 2 to 5, a plurality of R ¹¹¹ may be the same or different. A plurality of R ¹¹² may be the same or different when e represents an integer of 2 to 5, and a plurality of R ¹¹³ may be the same or different when f represents an integer of 2 to 5. When R represents an integer of 2 or more and 5 or less, the plurality of R ¹¹⁴ may be the same or different, and when h represents an integer of 2 or more and 5 or less, the plurality of R ¹¹⁵ may be the same or different, and i is 2 When an integer of 5 or less is represented, a plurality of R ¹¹⁶ may be the same or different.

In general formula (11), the alkyl group having 1 to 6 carbon atoms represented by R ^{111 to} R ¹¹⁶ is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. The alkyl group having 1 to 6 carbon atoms represented by R ^{111 to} R ¹¹⁶ may have a substituent. Examples of such a substituent include a halogen atom, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms.

In General Formula (11), the alkoxy group having 1 to 6 carbon atoms represented by R ^{111 to} R ¹¹⁶ may have a substituent. Examples of such a substituent include an alkoxy group having 1 to 6 carbon atoms or an aryl group having 6 to 14 carbon atoms.

In General Formula (11), the aryl group having 6 to 14 carbon atoms represented by R ^{111 to} R ¹¹⁶ may have a substituent. Examples of such a substituent include an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an aryl group having 6 to 14 carbon atoms.

In the general formula (11), R ¹¹¹ and R ¹¹⁴ represent an alkyl group having 1 to 6 carbon atoms, a, d and g represent 1, and e, f, h and i represent 0. Is preferred.

  Preferable examples of compound (11) include a compound represented by chemical formula (11-1) (hereinafter sometimes referred to as compound (11-1)).

In order to improve the filming resistance of the photoreceptor, the charge transport layer preferably contains a binder resin and a hole transport agent described below.
Whether the binder resin is a polyarylate resin (1-1) and the hole transport agent is a compound (10);
Whether the binder resin is a polyarylate resin (1-2) and the hole transport agent is a compound (10);
Whether the binder resin is a polyarylate resin (1-3) and the hole transport agent is a compound (10);
Whether the binder resin is a polyarylate resin (1-4) and the hole transport agent is a compound (10);
Whether the binder resin is a polyarylate resin (1-5) and the hole transport agent is a compound (10);
Whether the binder resin is a polyarylate resin (1-6) and the hole transport agent is a compound (10);
The binder resin is a polyarylate resin (2-1) and the hole transport agent is a compound (10); or the binder resin is a polyarylate resin (3-1) and the hole transport agent is a compound (10 ).

In order to improve the filming resistance of the photoreceptor, the charge transport layer preferably contains a binder resin and a hole transport agent described below.
Whether the binder resin is a polyarylate resin (1-1) and the hole transport agent is a compound (11);
Whether the binder resin is a polyarylate resin (1-2) and the hole transport agent is a compound (11);
Whether the binder resin is a polyarylate resin (1-3) and the hole transport agent is a compound (11);
Whether the binder resin is a polyarylate resin (1-4) and the hole transport agent is a compound (11);
Whether the binder resin is a polyarylate resin (1-5) and the hole transport agent is a compound (11);
Whether the binder resin is a polyarylate resin (1-6) and the hole transport agent is a compound (11);
The binder resin is a polyarylate resin (2-1) and the hole transport agent is a compound (11); or the binder resin is a polyarylate resin (3-1) and the hole transport agent is a compound (11). ).

(Base resin)
The base resin is not particularly limited as long as it can be applied to the photoreceptor. Examples of the base resin include a thermoplastic resin, a thermosetting resin, and a photocurable resin. Examples of thermoplastic resins include styrene resins, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, styrene-acrylic acid copolymers, acrylic copolymers, and polyethylene resins. , Ethylene-vinyl acetate copolymer, chlorinated polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer, vinyl chloride-vinyl acetate copolymer, alkyd resin, polyamide resin, urethane resin, polycarbonate resin, polyarylate resin, polysulfone Examples include resins, diallyl phthalate resins, ketone resins, polyvinyl butyral resins, polyether resins, and polyester resins. Examples of the thermosetting resin include silicone resin, epoxy resin, phenol resin, urea resin, melamine resin, and other crosslinkable thermosetting resins. Examples of the photocurable resin include epoxy acrylic resin or urethane-acrylic resin. These may be used individually by 1 type and may be used in combination of 2 or more type.

  The base resin contained in the charge generation layer is preferably different from the binder resin contained in the charge transport layer. In the production of a multilayer photoreceptor, for example, a charge generation layer is formed on a conductive substrate, and a charge transport layer is formed on the charge generation layer. At that time, a charge transport layer coating solution is applied onto the charge generation layer. Therefore, the charge generation layer is preferably not dissolved in the solvent of the charge transport layer coating solution.

(Additive)
The additive (4) is represented by the general formula (4).

In general formula (4), R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms which may have a halogen atom. Alternatively, it represents an aralkyl group having 7 to 20 carbon atoms. R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ may each independently have a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. A good aryl group having 6 to 14 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an amino group or a nitro group which may have a phenyl group. Of R ³ , R ⁴ , R ⁵ and R ⁶ , two substituents bonded to adjacent carbon atoms in the benzene ring may be bonded to each other to form an aromatic ring. Of R ⁷ , R ⁸ , R ⁹ and R ¹⁰ , two substituents bonded to adjacent carbon atoms in the benzene ring may be bonded to each other to form an aromatic ring.

In general formula (4), the alkyl group having 1 to 6 carbon atoms represented by R ¹ and R ² is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. The aryl group having 6 to 14 carbon atoms represented by R ¹ and R ² is preferably a phenyl group. The aryl group having 6 to 14 carbon atoms may have a halogen atom as a substituent. The aryl group having 6 to 14 carbon atoms which may have a halogen atom is preferably a phenyl group which may have a halogen atom, more preferably a phenyl group or an m-chlorophenyl group.

In general formula (4), alkyl groups having 1 to 6 carbon atoms represented by R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are bonded to each other to form an aromatic ring. Is preferably formed. The amino group which may have a phenyl group represented by R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ is preferably an amino group or a diphenylamino group.

In general formula (4), R ¹ and R ² each independently preferably represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a phenyl group which may have a halogen atom. R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are each independently one or more of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group. It preferably represents an amino group that may have.

  Examples of the additive (4) include compounds represented by chemical formula (4-1), chemical formula (4-2), chemical formula (4-3), or chemical formula (4-4) (hereinafter referred to as additive (4), respectively. -1) to (4-4)).

  The content of the additive is preferably 2 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin.

  The additive may contain other additives in addition to the additive (4). Other additives include, for example, electron acceptor compounds, deterioration inhibitors (more specifically, antioxidants, radical scavengers, quenchers or ultraviolet absorbers), softeners, surface modifiers, extenders. , Thickeners, dispersion stabilizers, waxes, donors, surfactants or leveling agents. 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.

<Intermediate layer>
An intermediate | middle layer contains 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.). Or 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 resin for the intermediate layer is not particularly limited as long as it can be used as a resin for forming the intermediate layer. The intermediate layer may contain an additive. Examples of the additive contained in the intermediate layer are the same as those of the additive contained in the photosensitive layer.

<Method for producing photoconductor>
The method for producing a photoreceptor includes a photosensitive layer forming step. The photosensitive layer forming step includes 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. The charge generation layer coating solution is a coating solution for forming the charge generation layer. A charge generation layer coating solution is applied onto a conductive substrate to form a coating film. Next, at least a part of the solvent contained in the coating film is removed to form a charge generation layer. The charge generation layer coating solution includes, for example, a charge generation agent, a solvent, and a component (for example, a base resin or an additive) added as necessary. Such a coating solution for a charge generation layer is prepared by dissolving or dispersing a charge generation agent and components added as necessary in a solvent.

  In the charge transport layer forming step, first, a charge transport layer coating solution is prepared. The charge transport layer coating solution is a coating solution for forming the charge transport layer. A charge transport layer coating solution is applied onto the charge generation layer to form a coating film. Next, at least a part of the solvent contained in the coating film is removed to form a charge transport layer. The charge transport layer coating solution contains at least a hole transport agent, a polyarylate resin (1), (2) or (3) as a binder resin, an additive (4), and a solvent. The charge transport layer coating solution is prepared by dissolving or dispersing a hole transport agent, a polyarylate resin (1), (2) or (3) as a binder resin, and an additive (4) in a solvent. can do. You may add an additive to the coating liquid for charge transport layers as needed.

  The solvent contained in the charge generation layer coating solution and the charge transport layer coating solution (hereinafter, these two coating solutions may be collectively referred to as the coating solution) dissolves each component contained in the coating solution. Or if it can disperse | distribute, it will not specifically limit. 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, xylene, etc.), halogenated hydrocarbons (more specifically, dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene, etc.), ethers (more specifically, dioxane, dimethyl ether, diethyl) Ether, tetrahydrofuran, ethylene glycol dimethyl ether or diethylene glycol dimethyl ether), ketone (more specifically, acetone, methyl ethyl ketone, cyclohexanone, etc.), ester (more specifically, ethyl acetate or methyl acetate, etc.), Methyl formaldehyde include dimethylformamide or dimethyl sulfoxide. These solvents may be used alone or in combination of two or more. Of these solvents, non-halogen solvents (solvents other than halogenated hydrocarbons) are preferably used.

  The solvent contained in the charge transport layer coating solution is preferably different from the solvent contained in the charge generation layer coating solution. This is because when the charge transport layer coating solution is applied onto the charge generation layer, it is preferable that the charge generation layer does not dissolve in the solvent of the charge transport layer coating solution.

  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.

  In order to improve the dispersibility of each component or the surface smoothness of each formed layer, the coating solution may contain, for example, a surfactant or a leveling agent.

  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 can evaporate the solvent in the coating solution. Examples of the removal method include heating, reduced pressure, or combined use of heating and reduced pressure. More specifically, a method of 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 as necessary. A known method can be selected as appropriate for the step of forming the intermediate layer.

<Second Embodiment: Image Forming Apparatus>
Next, the image forming apparatus 100 according to the second embodiment will be described with reference to FIG. FIG. 2 is a diagram illustrating an example of the structure of the image forming apparatus 100. The image forming apparatus 100 includes the photoconductor 30 according to the first embodiment.

  The image forming apparatus 100 is not particularly limited as long as it is an electrophotographic image forming apparatus. For example, the image forming apparatus 100 may be a monochrome image forming apparatus or a color image forming apparatus. When the image forming apparatus 100 is a color image forming apparatus, the image forming apparatus 100 employs, for example, a tandem method. Hereinafter, the tandem image forming apparatus 100 will be described as an example.

  The image forming apparatus 100 may employ a direct transfer method or an intermediate transfer method. Hereinafter, the image forming apparatus 100 that employs the direct transfer method will be described as an example.

  The image forming apparatus 100 includes image forming units 40a, 40b, 40c, and 40d, a transfer belt 50, and a fixing unit 54. 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. When the image forming apparatus 100 is a monochrome image forming apparatus, the image forming apparatus 100 includes an image forming unit 40a, and the image forming units 40b to 40d are omitted.

  The image forming unit 40 includes a photoconductor 30, a charging unit 42, an exposure unit 44, a developing unit 46, and a transfer unit 48. A photoreceptor 30 is provided at the center position of the image forming unit 40. The photoconductor 30 is provided so as to be rotatable in the arrow direction (counterclockwise). Around the photoconductor 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 photoconductor 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).

  The charging unit 42 charges the surface (specifically, the peripheral surface) of the photoreceptor 30 to a negative polarity. The charging unit 42 is a non-contact method or a contact method. An example of the non-contact charging unit 42 is a corotron charger or a scorotron charger. An example of the contact-type charging unit 42 is a charging roller or a charging brush.

  The charging unit 42 can negatively charge the surface of the photoconductor 30 while the charging unit 42 contacts the surface of the photoconductor 30. That is, the charging unit 42 can be a contact method. In the image forming apparatus 100 including the contact-type charging unit 42, minute components (for example, paper powder, toner, or external additive) attached to the surface of the photoreceptor 30 are easily fixed, and filming is likely to occur. However, the photosensitive member 30 according to the first embodiment can suppress the occurrence of filming as already described. Therefore, even when the image forming apparatus 100 includes the contact-type charging unit 42, the occurrence of filming can be suitably suppressed.

  As the contact charging unit 42, a charging roller can be used. For example, the charging roller rotates following the rotation of the photoconductor 30 while contacting the surface of the photoconductor 30. For example, at least a surface portion of the charging roller is formed of a resin. The charging roller includes, for example, a core metal rotatably supported, a resin layer formed on the core metal, and a voltage applying unit that applies a voltage to the core metal. The charging unit 42, which is such a charging roller, charges the surface of the photoreceptor 30 that is in contact via the resin layer when the voltage application unit applies a voltage to the cored bar. Examples of the resin contained in the resin layer of the charging roller are a silicone resin, a urethane resin, or a silicone-modified resin. The resin layer may contain an inorganic filler.

  The exposure unit 44 exposes the surface of the charged photoreceptor 30. As a result, an electrostatic latent image is formed on the surface of the photoreceptor 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 electrostatic latent image formed on the photoconductor 30. As a result, the electrostatic latent image is developed as a toner image. The photoreceptor 30 corresponds to an image carrier that carries a toner image. The toner may be used as a one-component developer. Alternatively, the toner and the desired carrier may be mixed and used in the two-component developer. When toner is used as a one-component developer, the developing unit 46 supplies toner that is a one-component developer to the electrostatic latent image formed on the photoreceptor 30. When the toner is used in the two-component developer, the developing unit 46 supplies toner out of the toner and the carrier contained in the two-component developer to the electrostatic latent image formed on the photoreceptor 30.

  The developing unit 46 can develop the electrostatic latent image as a toner image while in contact with the photoreceptor 30. That is, the image forming apparatus 100 can employ a so-called contact development method.

  The developing unit 46 can clean the surface of the photoreceptor 30. In other words, the image forming apparatus 100 can employ a so-called cleaner-less method. The developing unit 46 can remove components remaining on the surface of the photoconductor 30 (hereinafter sometimes referred to as “residual components”). An example of the residual component is a toner component, and more specifically, a toner or a free external additive. Another example of the residual component is a non-toner component, and more specifically, a minute component (for example, paper dust) of the recording medium M. In the image forming apparatus 100 that employs the cleaner-less method, residual components on the surface of the photoreceptor 30 are not scraped off by a cleaning unit (for example, a cleaning blade). Therefore, in the image forming apparatus 100 adopting the cleaner-less method, usually, residual components are likely to remain on the surface of the photoconductor 30, and filming is likely to occur on the surface of the photoconductor 30 due to the residual components. However, the image forming apparatus 100 includes the photoconductor 30. As already described, the photoconductor 30 has excellent filming resistance. For this reason, even when the image forming apparatus 100 adopts the cleaner-less method, the image forming apparatus 100 can suppress image defects due to filming.

In order for the developing unit 46 to efficiently clean the surface of the photoreceptor 30, it is preferable to satisfy the following conditions (a) and (b).
Condition (a): A contact developing method is adopted, and a circumferential speed (rotational speed) difference is provided between the photosensitive member 30 and the developing unit 46.
Condition (b): The surface potential of the photoconductor 30 and the potential of the developing bias satisfy the following formulas (b-1) and (b-2).
0 (V) <potential of developing bias (V) <surface potential of unexposed area of photoreceptor 30 (V) (b-1)
Development bias potential (V)> Surface potential (V) of exposed area of photoreceptor 30> 0 (V) (b-2)

  When the contact development method shown in the condition (a) is employed and a peripheral speed difference is provided between the photosensitive member 30 and the developing unit 46, the surface of the photosensitive member 30 comes into contact with the developing unit 46, and the photosensitive member 30 is exposed. The adhering component on the surface is removed by friction with the developing section 46. The peripheral speed of the developing unit 46 is preferably faster than the peripheral speed of the photoconductor 30.

  Condition (b) assumes a case where the development method is a reversal development method. It is preferable that the charging polarity of the toner, the surface potential of the unexposed area of the photoconductor 30, the surface potential of the exposed area of the photoconductor 30 and the potential of the developing bias are all negative. It should be noted that the surface potential of the unexposed area and the exposed area of the photoconductor 30 are determined by the transfer unit 48 transferring the toner image from the photoconductor 30 to the recording medium M, and then the charging unit 42 of the next photoconductor 30. Measured before charging the surface.

  When the mathematical expression (b-1) of the condition (b) is satisfied, the electrostatic force acting between the toner remaining on the photoconductor 30 (hereinafter sometimes referred to as “residual toner”) and the unexposed area of the photoconductor 30. The repulsive force is larger than the electrostatic repulsive force acting between the residual toner and the developing unit 46. Therefore, the residual toner in the unexposed area of the photoconductor 30 moves from the surface of the photoconductor 30 to the developing unit 46 and is collected.

  When the mathematical expression (b-2) of the condition (b) is satisfied, the electrostatic repulsive force acting between the residual toner and the exposed area of the photoconductor 30 acts on the electrostatic force acting between the residual toner and the developing unit 46. Smaller than the repulsive force. Therefore, the residual toner in the exposed area of the photoconductor 30 is held on the surface of the photoconductor 30. The toner held in the exposure area of the photoreceptor 30 is used as it is for image formation.

  The transfer belt 50 conveys the recording medium M between the photoconductor 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 photoreceptor 30 to the transfer target. When the image forming apparatus 100 employs the direct transfer method, the transfer target corresponds to the recording medium M. When the image forming apparatus 100 employs the direct transfer method, the photoconductor 30 is in contact with the recording medium M when the toner image is transferred from the photoconductor 30 to the recording medium M. The transfer unit 48 is, for example, a transfer roller.

  Normally, in an image forming apparatus that employs the direct transfer method, since the photosensitive member contacts the recording medium M, minute components of the recording medium M easily adhere to the surface of the photosensitive member, and image defects due to filming occur. easy. However, as already described, the photoreceptor 30 according to the first embodiment is excellent in filming resistance. Therefore, even when the image forming apparatus 100 adopts the direct transfer method, the image forming apparatus 100 including the photoreceptor 30 can suppress the occurrence of image defects due to filming.

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

  The fixing unit 54 heats and / or pressurizes the unfixed toner image transferred to the recording medium M by the transfer unit 48. The fixing unit 54 is, for example, one or both of a heating roller and a pressure roller. The toner image is fixed on the recording medium M by heating and / or pressurizing the toner image. As a result, an image is formed on the recording medium M.

<Third embodiment: Process cartridge>
With continued reference to FIG. 2, the process cartridge according to the third embodiment will be described. The process cartridge according to the third embodiment includes the photoconductor 30 according to the first embodiment. The process cartridge is an image forming cartridge. The process cartridge corresponds to each of the image forming units 40a to 40d. The process cartridge includes a photoreceptor 30. The process cartridge includes at least one selected from the group consisting of a charging unit 42, an exposure unit 44, a developing unit 46, and a transfer unit 48 in addition to the photoreceptor 30. The process cartridge may further include one or both of a cleaning unit (not shown) and a charge removal unit (not shown). However, the process cartridge may adopt a cleaner-less method. The process cartridge is designed to be detachable from the image forming apparatus 100. Therefore, the process cartridge is easy to handle, and when the sensitivity characteristic of the photoconductor 30 is deteriorated, the process cartridge including the photoconductor 30 can be easily and quickly replaced.

  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.

  The following charge generating agents were prepared as materials for forming the charge generating layer of the photoreceptor. In addition, the following hole transport agent and binder resin were prepared as materials for forming the charge transport layer of the photoreceptor.

(Charge generator)
As a charge generating agent, Y-type titanyl phthalocyanine represented by the chemical formula (CGM-2) described in the first embodiment was prepared.

(Hole transport agent)
As the hole transport agent, the compounds (10-1) and (11-1) described in the first embodiment were prepared.

(Binder resin)
As the binder resin, a polyarylate resin represented by chemical formulas (R-1) to (R-8) (hereinafter sometimes referred to as polyarylate resins (R-1) to (R-8)). Each was made. The chemical formulas (R-5) and (R-6) correspond to the chemical formulas (1-5) and (1-6) described in the first embodiment, respectively.

[Preparation of polyarylate resin (R-1)]
A three-necked flask was used as a reaction vessel. This three-necked flask was equipped with a thermometer, a three-way cock and a dropping funnel having a capacity of 200 mL. In a reaction vessel, 12.24 g (41.28 mmol) of 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane (compound (BP-1) described in the first embodiment), tert-butylphenol, 062 g (0.413 mmol), sodium hydroxide 3.92 g (98 mmol) and benzyltributylammonium chloride 0.120 g (0.384 mmol) were added. Subsequently, the air in the reaction vessel was replaced with argon gas. 600 mL of water was added to the contents of the reaction vessel. The contents of the reaction vessel were stirred at 20 ° C. for 1 hour. Next, the content of the reaction vessel was cooled until the temperature of the content of the reaction vessel reached 10 ° C., and an alkaline aqueous solution I was obtained.

  On the other hand, 4.52 g (16.2 mmol) of biphenyl-4,4′-dicarboxylic acid dichloride (dichloride of the compound (DC-3) described in the first embodiment) and naphthalene-2,6-dicarboxylic acid dichloride ( 4.10 g (16.2 mmol) of the compound (DC-4 dichloride) described in the first embodiment was dissolved in 300 g of chloroform to obtain a chloroform solution II.

  Subsequently, chloroform solution II was thrown into alkaline aqueous solution I, stirring alkaline aqueous solution I at 10 degreeC. This initiated a polymerization reaction. While adjusting the temperature (liquid temperature) of the contents of the reaction vessel to 13 ± 3 ° C., the contents of the reaction vessel were stirred for 3 hours to proceed the polymerization reaction. Subsequently, the upper layer (water layer) in the contents of the reaction vessel was removed using a decant to obtain an organic layer. Next, 500 mL of ion-exchanged water was put into a 2 L Erlenmeyer flask. The resulting organic layer was added to the flask contents. To the flask contents, 300 g of chloroform and 6 mL of acetic acid were further added. The flask contents were then stirred at room temperature (25 ° C.) for 30 minutes. Thereafter, the upper layer (aqueous layer) in the flask contents was removed using a decant to obtain an organic layer. The obtained organic layer was washed with 500 mL of ion exchange water using a separatory funnel. Washing with ion-exchanged water was repeated 8 times. As a result, an organic layer washed with water was obtained. The organic layer washed with water was filtered to obtain a filtrate. 1.5 L of methanol was put into a 3 L beaker. The filtrate (organic layer) was slowly added dropwise with stirring methanol to obtain a precipitate. The precipitate was removed by filtration. The obtained precipitate was vacuum-dried at a temperature of 70 ° C. for 12 hours. As a result, polyarylate resin (R-1) was obtained. It was 12.2 g of polyarylate resin (R-1), and the yield was 77 mol%. The resulting polyarylate resin (R-1) had a viscosity average molecular weight of 46,000.

[Preparation of polyarylate resin (R-2)]
A polyarylate resin (R-2) was produced in the same manner as the production of the polyarylate resin (R-1) except that the following points were changed. 4.52 g (16.2 mmol) of dichloride of compound (DC-3) and 4.10 g (16.2 mmol) of dichloride of compound (DC-4) were converted to 16.2 mmol of dichloride of compound (DC-1) and Compound (DC-4) was changed to 16.2 mmol of dichloride. The resulting polyarylate resin (R-2) had a viscosity average molecular weight of 47,500.

[Preparation of polyarylate resin (R-3)]
A polyarylate resin (R-3) was produced in the same manner as the production of the polyarylate resin (R-1) except that the following points were changed. 4.52 g (16.2 mmol) of the dichloride of the compound (DC-3) and 4.10 g (16.2 mmol) of the dichloride of the compound (DC-4) were converted into 16.2 mmol of the dichloride of the compound (DC-3) and The compound (DC-1) was changed to 16.2 mmol of dichloride. The resulting polyarylate resin (R-3) had a viscosity average molecular weight of 46,500.

[Preparation of polyarylate resin (R-4)]
A polyarylate resin (R-4) was produced in the same manner as the production of the polyarylate resin (R-1) except that the following points were changed. 4.52 g (16.2 mmol) of the dichloride of the compound (DC-3) and 4.10 g (16.2 mmol) of the dichloride of the compound (DC-4) were converted into 16.2 mmol of the dichloride of the compound (DC-2) and The compound (DC-1) was changed to 16.2 mmol of dichloride. The resulting polyarylate resin (R-4) had a viscosity average molecular weight of 48,200.

[Preparation of polyarylate resin (R-5)]
A polyarylate resin (R-5) was produced in the same manner as the production of the polyarylate resin (R-1) except that the following points were changed. 4.52 g (16.2 mmol) of dichloride of compound (DC-3) and 4.10 g (16.2 mmol) of dichloride of compound (DC-4) were converted to 32.4 mmol of dichloride of compound (DC-1). changed. The resulting polyarylate resin (R-5) had a viscosity average molecular weight of 49,000.

[Preparation of polyarylate resin (R-6)]
A polyarylate resin (R-6) was produced in the same manner as the production of the polyarylate resin (R-1) except that the following points were changed. The dichloride 4.52 g (16.2 mmol) of the compound (DC-3) and the dichloride 4.10 g (16.2 mmol) of the compound (DC-4) were converted into 32.4 mmol of the dichloride of the compound (DC-2). changed. The resulting polyarylate resin (R-6) had a viscosity average molecular weight of 47,600.

[Preparation of polyarylate resin (R-7)]
A three-necked flask was used as a reaction vessel. This three-necked flask was equipped with a thermometer, a three-way cock and a dropping funnel having a capacity of 200 mL. In a reaction vessel, 25.63 g (82.86 mmol) of 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (compound (BP-7) described in the first embodiment), tert -0.124 g (0.826 mmol) of butylphenol, 7.84 g (196 mmol) of sodium hydroxide, and 0.240 g (0.768 mmol) of benzyltributylammonium chloride were charged. Subsequently, the air in the reaction vessel was replaced with argon. Thereafter, 600 mL of water was charged into the reaction vessel. The contents of the reaction vessel were stirred for 1 hour under the condition of the internal temperature of the reaction vessel of 20 ° C. Next, the contents of the reaction vessel were cooled, and the internal temperature of the reaction vessel was lowered to 10 ° C. As a result, alkaline aqueous solution III was obtained.

  9.84 g (38.9 mmol) of naphthalene-2,6-dicarboxylic acid dichloride (dichloride of the compound (DC-4) described in the first embodiment) and 4,4′-oxybisbenzoic acid chloride (first implementation) A chloroform solution IV was prepared by dissolving 11.47 g (38.9 mmol) of the compound (DC-1 dichloride) described in the form in 300 g of chloroform.

  The temperature of the alkaline aqueous solution III was 10 ° C. Using a dropping funnel, the chloroform solution IV was slowly added dropwise to the alkaline aqueous solution III over 110 minutes. This initiated a polymerization reaction. While adjusting the temperature (liquid temperature) of the contents of the reaction vessel to 13 ± 3 ° C., the contents of the reaction vessel were stirred for 3 hours to proceed the polymerization reaction. Subsequently, the upper layer (water layer) in the contents of the reaction vessel was removed using a decant to obtain an organic layer. Next, 500 mL of ion-exchanged water was put into a 2 L Erlenmeyer flask. The resulting organic layer was added to the flask contents. To the flask contents, 300 g of chloroform and 6 mL of acetic acid were further added. The flask contents were then stirred at room temperature (25 ° C.) for 30 minutes. Thereafter, the upper layer (aqueous layer) in the flask contents was removed using a decant to obtain an organic layer. The obtained organic layer was washed with 500 mL of ion exchange water using a separatory funnel. Washing with ion-exchanged water was repeated 8 times. As a result, an organic layer washed with water was obtained. The organic layer washed with water was filtered to obtain a filtrate. 1.5 L of methanol was put into a 3 L beaker. The filtrate (organic layer) was slowly added dropwise with stirring methanol to obtain a precipitate. The precipitate was removed by filtration. The obtained precipitate was vacuum-dried at a temperature of 70 ° C. for 12 hours. As a result, a polyarylate resin (Resin-7) was obtained. The yield of polyarylate resin (Resin-7) was 35.3 g, and the yield was 88.7 mol%. The resulting polyarylate resin (R-7) had a viscosity average molecular weight of 48,000.

[Preparation of polyarylate resin (R-8)]
A 1 L three-necked flask was used as a reaction vessel. This three-necked flask was equipped with a thermometer, a three-way cock and a dropping funnel having a capacity of 200 mL. In a reaction vessel, 31.25 g (82.56 mmol) of 9,9-bis (4-hydroxy-3-methylphenyl) fluorene (compound (BP-3) described in the first embodiment), tert-butylphenol, 0. 124 g (0.826 mmol), sodium hydroxide 7.84 g (196 mmol) and benzyltributylammonium chloride 0.240 g (0.768 mmol) were added. Subsequently, the air in the reaction vessel was replaced with argon. Thereafter, 600 mL of water was charged into the reaction vessel. The contents of the reaction vessel were stirred for 1 hour under the condition of the internal temperature of the reaction vessel of 20 ° C. Next, the contents of the reaction vessel were cooled, and the internal temperature of the reaction vessel was lowered to 10 ° C. As a result, an alkaline aqueous solution V was obtained.

  9.84 g (38.9 mmol) of naphthalene-2,6-dicarboxylic acid dichloride (dichloride of the compound (DC-4) described in the first embodiment) and 4,4′-oxybisbenzoic acid chloride (first implementation) A chloroform solution VI was prepared by dissolving 11.47 g (38.9 mmol) of the compound (DC-1 dichloride) described in the form in 300 g of chloroform.

  Subsequently, chloroform solution VI was thrown into alkaline aqueous solution V, stirring alkaline aqueous solution V at 10 degreeC. This initiated a polymerization reaction. While adjusting the temperature (liquid temperature) of the contents of the reaction vessel to 13 ± 3 ° C., the contents of the reaction vessel were stirred for 3 hours to proceed the polymerization reaction. Subsequently, the upper layer (water layer) in the contents of the reaction vessel was removed using a decant to obtain an organic layer. Next, 500 mL of ion-exchanged water was put into a 2 L Erlenmeyer flask. The resulting organic layer was added to the flask contents. To the flask contents, 300 g of chloroform and 6 mL of acetic acid were further added. The flask contents were then stirred at room temperature (25 ° C.) for 30 minutes. Thereafter, the upper layer (aqueous layer) in the flask contents was removed using a decant to obtain an organic layer. The obtained organic layer was washed with 500 mL of ion exchange water using a separatory funnel. Washing with ion-exchanged water was repeated 8 times. As a result, an organic layer washed with water was obtained. The organic layer washed with water was filtered to obtain a filtrate. 1.5 L of methanol was put into a 3 L beaker. The filtrate (organic layer) was slowly added dropwise with stirring methanol to obtain a precipitate. The precipitate was removed by filtration. The obtained precipitate was vacuum-dried at a temperature of 70 ° C. for 12 hours. As a result, polyarylate resin (R-8) was obtained. The yield of polyarylate resin (R-8) was 39.7 g, and the yield was 88.1%. The resulting polyarylate resin (R-8) had a viscosity average molecular weight of 40,000.

Next, ¹ H-NMR spectra of the prepared polyarylate resins (R-1) to (R-8) were measured using a proton nuclear magnetic resonance spectrometer (manufactured by JASCO Corporation, 300 MHz). CDCl ₃ was used as the solvent. Tetramethylsilane (TMS) was used as an internal standard sample. Among these, polyarylate resins (R-1), (R-2), (R-3), (R-7) and (R-8) are given as representative examples. FIG. 3 shows the ¹ H-NMR spectrum of the polyarylate resin (R-1). FIG. 4 shows the ¹ H-NMR spectrum of the polyarylate resin (R-2). FIG. 5 shows the ¹ H-NMR spectrum of the polyarylate resin (R-3). FIG. 6 shows the ¹ H-NMR spectrum of polyarylate resin (R-7). FIG. 7 shows the ¹ H-NMR spectrum of polyarylate resin (R-8). 3 to 7, the horizontal axis represents chemical shift (unit: ppm), and the vertical axis represents signal intensity (unit: arbitrary unit). The chemical shift values of polyarylate resins (R-7) and (R-8) are shown below.
Polyarylate resin (R-7): ¹ H-NMR (300 MHz, CDCl ₃ ) δ = 8.81 (d, 2H), 8.17-8.26 (m, 6H), 8.09 (d, 2H) ), 7.02-7.48 (m, 20H), 2.74 (brs, 2H), 2.50 (brs, 2H), 2.02 (brm, 4H), 1.41 (brs, 2H) , 1.23 (brs, 2H), 0.99 (d, 12H), 0.42 (d, 6H).
Polyarylate resin (R-8): ¹ H-NMR (300 MHz, CDCl ₃ ) δ = 8.81 (s, 1H), 8.26 (d, 1H), 8.20 (d, 2H), 8. 09 (d, 1H), 7.74-7.80 (m, 2H), 7.28-7.48 (m, 7H), 6.99-7.18 (m, 7H), 2.11 2.18 (m, 6H).

^{According to 1} H-NMR spectrum and chemical shift value, polyarylate resins (R-1), (R-2), (R-3), (R-7) and (R-8) are obtained. confirmed. Other polyarylate resin (R-4), (R -5) and (R-6) in the same way also, by ¹ H-NMR spectrum and chemical shift values, respectively polyarylate resin (R-4), ( It was confirmed that R-5) and (R-6) were obtained.

  In addition to the polyarylate resins (R-1) to (R-8), polyarylate resins represented by the chemical formulas (R-B1) to (R-B4) (hereinafter referred to as polyarylate resins (R-B1)) To (R-B4) may also be prepared. The subscripts attached to the repeating units in chemical formulas (R-B1) to (R-B4) each represent the percentage of the number of repeating units attached with the subscripts relative to the total number of repeating units contained in the resin. . The viscosity average molecular weights of the polyarylate resins (R-B1) to (R-B4) were 46,500, 47200, 49100 and 48600, respectively.

<Manufacture of photoconductor>
Photoconductors (A-1) to (A-12) and (B-1) to (B-5) were produced using the charge generator, hole transport agent and binder resin described above.

(Manufacture of photoconductor (A-1))
First, an intermediate layer was formed. Surface-treated titanium oxide (“Prototype SMT-A” manufactured by Teika Co., Ltd., number average primary particle size 10 nm) was prepared. More specifically, titanium oxide was surface-treated with alumina and silica, and the surface-treated titanium oxide was further surface-treated with methylhydrogenpolysiloxane while being wet-dispersed. Next, surface-treated titanium oxide (2 parts by mass) and a polyamide resin (quaternary polyamide resin of “Amilan (registered trademark) CM8000”, polyamide 6, polyamide 12, polyamide 66 and polyamide 610 manufactured by Toray Industries, Inc.) (1 part by mass) was added to a solvent containing methanol (10 parts by mass), butanol (1 part by mass) and toluene (1 part by mass). Using a bead mill, these materials and the solvent were mixed for 5 hours to disperse the materials in the solvent. This obtained the coating liquid for intermediate | middle layers. The obtained intermediate layer coating solution was filtered using a filter having an opening of 5 μm. Then, the intermediate layer coating solution was applied to the surface of the conductive substrate using a dip coating method. As the conductive substrate, an aluminum drum-shaped support (diameter 30 mm, total length 246 mm) was used. Subsequently, the applied intermediate layer coating solution was dried at 130 ° C. for 30 minutes to form an intermediate layer (film thickness: 2 μm) on the conductive substrate.

  Next, a charge generation layer was formed. Specifically, Y-type titanyl phthalocyanine (1.5 parts by mass) as a charge generating agent and polyvinyl acetal resin (“S-REC BX-5” manufactured by Sekisui Chemical Co., Ltd.) (1 part by mass) as a base resin, It added to the solvent containing propylene glycol monomethyl ether (40 mass parts) and tetrahydrofuran (40 mass parts). Using a bead mill, these materials and the solvent were mixed for 2 hours, and the materials were dispersed in the solvent to prepare a charge generation layer coating solution. The obtained coating solution for charge generation layer was filtered using a filter having an opening of 3 μm. Next, the obtained filtrate was applied on the intermediate layer 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.

  Next, a charge transport layer was formed. Specifically, 75 parts by mass of the compound (10-1) as a hole transport agent and 0.5 parts by mass of a hindered phenol antioxidant (“Irganox (registered trademark) 1010” manufactured by BASF Corporation) as an additive And 100 mass parts of polyarylate resin (R-1) as binder resin, 10 mass parts of additive (4-1), and 700 mass parts of mixed solvents were mixed. The mixed solvent contained 350 parts by mass of tetrahydrofuran and 350 parts by mass of toluene as a solvent. The materials (hindered phenol antioxidant, polyarylate resin (R-1) and additive (4-1)) were dispersed in the solvent. This prepared the coating liquid for charge transport layers. The obtained coating solution for charge transport layer was applied onto the charge generation layer using a dip coating method and dried at 120 ° C. for 40 minutes. Thereby, a charge transport layer (film thickness 20 μm) was formed on the charge generation layer. As a result, a photoreceptor (A-1) was obtained. The photoreceptor (A-1) was a multilayer electrophotographic photoreceptor. In the photoreceptor (A-1), an intermediate layer was provided on the conductive substrate, a charge generation layer was provided on the intermediate layer, and a charge transport layer was provided on the charge generation layer. In the photoreceptor (A-1), the charge transport layer is a single layer and is provided as the outermost surface layer.

(Production of photoconductors (A-2) to (A-12) and (B-1) to (B-5))
Photoconductors (A-2) to (A-12) and (B) were produced in the same manner as the production of photoconductor (A-1) except that the following points (1), (2) and (3) were changed. -1) to (B-5) were produced.
(1) In the production of the photoreceptor (A-1), the polyarylate resin (R-1) was used as the binder resin, but the photoreceptors (A-2) to (A-12) and (B-1) to In each manufacture of (B-5), the binder resin of the kind shown in Table 1 was used.
(2) In the production of the photoreceptor (A-1), the compound (10-1) was used as the hole transport agent, but the photoreceptors (A-2) to (A-12) and (B-1) to In each production of (B-5), hole transport agents of the types shown in Table 1 were used.
(3) The additive (4-1) was used in the production of the photoreceptor (A-1), but the photoreceptors (A-2) to (A-12), (B-1) and (B-3) were used. ) To (B-5), the additive (4) of the type shown in Table 1 was used. In the production of the photoreceptor (B-2), the additive (4) was not used.

<Measurement of elastic power>
The elastic powers of the photosensitive layers of the photoreceptors (A-1) to (A-12) and the photoreceptors (B-1) to (B-5) were measured. 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 relative humidity of 50% RH. Measurement was performed by performing Step 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 mmN, and the maximum deformation work (EW ₁ : plastic deformation) when the load 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 calculated. The elastic power measurement conditions were as follows.
[Elastic power measurement conditions]
Measurement mode: dF / dt = const
Maximum load: 9.8mmN
Loading time: 30 seconds Unloading time: 30 seconds Creep time: 5 seconds

  The elastic power was measured at five locations on the surface of the photosensitive layer, and the number average value of the elastic power was obtained. Table 1 shows the number average value of the elastic power.

<Measurement of scratch depth>
The scratch depth of each photosensitive layer of the photoreceptors (A-1) to (A-12) and the photoreceptors (B-1) to (B-5) was measured. The scratch depth is stipulated by JIS K5600-5-5 (Japanese Industrial Standard K5600: Paint General Test Method, Part 5: Mechanical Properties of Coating Film, Section 5: Scratch Hardness (Load Needle Method)). Measurement was performed using the apparatus 200.

  Hereinafter, the scratching apparatus 200 will be described with reference to FIG. FIG. 8 is a diagram illustrating an example of the configuration of the scratching apparatus 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).

  In FIG. 8, 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. Note that the X-axis direction, the Y-axis direction, and the Z-axis direction in FIGS. 9 to 11 described later are also synonymous with FIG.

  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. 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 30) to the upper surface 201a of the fixing base 201. The upper surface 201a of the fixed base 201 is a horizontal plane.

  The scratch needle 203 has a tip 203b (see FIG. 9). 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 portion 204 supports the scratch needle 203. The support arm portion 204 rotates around the support shaft 204a in a direction in which the scratch needle 203 approaches and separates from the photoreceptor 30.

  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. The fixed base 201 is attached between the two rail portions 207. The fixed base 201 can move horizontally along the rail portion 207 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 is moved along the rail portion 207 in the longitudinal direction (X-axis direction) of the fixed base 201.

  Hereinafter, a method for measuring the scratch depth will be described. The scratch depth measurement method included a first step, a second step, a third step, and a fourth step. The scratch depth was measured using a scratch device 200 defined by JIS K5600-5-5. As the scratching 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 relative humidity of 50% RH. The shape of the photoconductor 30 was a drum shape (cylindrical shape). By adopting the following scratch depth measurement method, it was possible to accurately measure the characteristics of the photosensitive layer 32 that affect the occurrence of filming.

(First step)
In the first step, the photosensitive member 30 is fixed to the upper surface 201 a of the fixing base 201 so that the longitudinal direction of the photosensitive member 30 is parallel to the longitudinal direction of the fixing base 201. The direction of the central axis L ₂ (rotation axis) of the photoconductor 30 corresponds to the longitudinal direction of the photoconductor 30. When the photoconductor 30 is in a sheet form, the long side direction of the photoconductor 30 corresponds to the longitudinal direction of the photoconductor 30.

(Second step)
In the second step, the scratch needle 203 was brought into contact with the surface 32 a of the photosensitive layer 32 of the photosensitive member 30 perpendicularly. With reference to FIG. 9 and FIG. 10 in addition to FIG. 8, a method of bringing the scratch needle 203 vertically into contact with the surface 32a of the photosensitive layer 32 of the drum-shaped photoreceptor 30 will be described. 9 is a cross-sectional view taken along line IX-IX shown in FIG. FIG. 9 is a cross-sectional view when the scratch needle 203 is brought into contact with the photoconductor 30. FIG. 10 is a side view of the fixing base 201, the scratch needle 203, and the photoconductor 30 shown in FIG.

As an extension of the center axis A ₁ of the scratching needle 203 is perpendicular to the upper surface 201a of the fixed base 201, it was a scratch needle 203 close to the photosensitive member 30. Then, the tip 203b of the scratching needle 203 was brought into contact with the point of the surface 32a of the photosensitive layer 32 of the photoconductor 30 that was farthest from the upper surface 201a of the fixing base 201 in the vertical direction (Z-axis direction). Thus, the tip 203b of the scratching needle 203 is a contact point P _3, the contact with the surface 32a of the photoconductive layer 32 of the photoconductor 30. Further, the center axis A ₁ of the scratching needle 203 to be perpendicular to the tangent A _2, the distal end 203b of the scratching needle 203 is brought into contact with the photosensitive member 30. The tangent line A ₂ is a tangent line at the contact point P ₃ of the outer circumference circle formed by the cross section of the photoconductor 30 perpendicular to the central axis L ₂ of the photoconductor 30. As a result, the scratch needle 203 abuts on the surface 32 a of the photosensitive layer 32 of the photosensitive member 30 vertically. Incidentally, in the case where the photosensitive member 30 is a sheet-like, to the surface 32a of the photoconductive layer 32 of the photoreceptor 30 (plane), as an extension of the center axis A ₁ of the scratching needle 203 are vertical scratch The needle 203 is brought into contact with the surface 32 a of the photosensitive layer 32.

When the scratching needle 203 was brought into contact with the above-described method, the positional relationship among the fixing base 201, the photoconductor 30 and the scratching needle 203 was as follows. The extension line of the central axis A ₁ of the scratching needle 203 and the central axis L ₂ of the photosensitive member 30 intersect perpendicularly at the intersection P ₂ . The contact point P ₁ between the photosensitive layer 32 and the upper surface 201 a, the intersection point P _2, and the contact point P ₃ between the photosensitive layer 32 and the tip 203 _b of the scratching needle 203 are located on an extension line of the central axis A ₁ of the scratching needle 203. It was. Further, the extension line of the central axis A ₁ of the scratch needle 203 was perpendicular to the upper surface 201 a of the fixing base 201 and the tangent line A ₂ .

(Third step)
In the third step, a load W of 10 g was applied from the scratching needle 203 to the photosensitive layer 32 in a state where the scratching needle 203 was in contact with the surface 32a of the photosensitive layer 32 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 moved horizontally along the rail portion 207 in the longitudinal direction (X-axis direction) of the fixed base 201. 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 is located on the downstream side of the first position N _{1 in} the longitudinal direction of the fixed base 201 and in the direction in which the fixed base 201 is separated from the two shaft support portions 205. With the movement of the fixed base 201 in the longitudinal direction, the photoconductor 30 also moved horizontally in the longitudinal direction of the fixed base 201. The moving speed of the fixing table 201 and the photosensitive member 30 was 30 mm / min. The moving distance of the fixed base 201 and the photosensitive member 30 was 30 mm. Moving distance of the fixed base 201 and the photosensitive body 30, 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 photoreceptor 30, the scratch S was formed on the surface 32 a of the photosensitive layer 32 of the photoreceptor 30 by the scratch needle 203. The scratch S will be described with reference to FIG. 11 in addition to FIGS. FIG. 11 shows a scratch S formed on the surface 32 a of the photosensitive layer 32. 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. 10. The line L ₃ is a line composed of a plurality of contact points P ₃ . 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 30. 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 depth Ds _max of the scratch S was measured. Specifically, the photosensitive member 30 was removed from the fixed base 201. Using a three-dimensional interference microscope (Bruker's “WYKO NT-1100”), the scratch S formed on the photosensitive layer 32 of the photoreceptor 30 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 corresponds to the distance from the tangent line A ₂ to the valley of the scratch S. The maximum depth Ds _max among the depths Ds of the scratch S was defined as the scratch depth. Table 1 shows the measured scratch depth (unit: μm).

<Evaluation of filming resistance>
Filming resistance was evaluated for each of the photoreceptors (A-1) to (A-12) and the photoreceptors (B-1) to (B-5). The evaluation machine was a modified machine obtained by modifying a color printer (“ECOSYS (registered trademark) FS-C5400DN” manufactured by Kyocera Document Solutions Co., Ltd.) into 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. The charging potential of the photoreceptor was set to -600V.

The photoconductor was mounted on an evaluation machine. The toner cartridge of the evaluator was filled with cyan toner. Printing was performed on 2,000 sheets at intervals of 16 seconds using an evaluation machine under a high temperature and high humidity environment (environment at a temperature of 32 ° C. and a relative humidity of 85% RH: hereinafter referred to as HH environment). . Next, printing is performed on 2,000 sheets at intervals of 16 seconds using an evaluator in a low-temperature and low-humidity environment (environment at a temperature of 10 ° C. and a relative humidity of 15% RH: hereinafter sometimes referred to as LL environment). did. After printing on 2,000 sheets in the LL environment, the evaluation machine was allowed to stand for 2 hours. Next, a solid image (image density 100%) was printed on one sheet in an LL environment. The obtained solid image was used as an evaluation image. The evaluation image was visually observed to confirm whether the image was missing. In addition, when filming occurs on the surface of the photoconductor, there is a tendency that a chip appears in the image. The filming resistance of the photoreceptor was evaluated according to the following criteria. Table 1 shows the evaluation results of the filming resistance.
[Evaluation criteria for filming resistance]
Evaluation A (particularly good): No missing image was confirmed.
Evaluation B (good): Slight chipping of the image was confirmed, but it was chipping to the extent that there was no problem in actual use.
Evaluation C (defect): The lack of image was clearly confirmed.

  In Table 1, resin and HTM represent a binder resin and a hole transport agent, respectively.

  Each of the photoreceptors (A-1) to (A-12) was provided with a conductive substrate and a photosensitive layer. The photosensitive layer included a charge generation layer and a charge transport layer. The charge generation layer contained a charge generation agent. The charge transport layer contained a hole transport agent, a binder resin, and an additive. The charge transport layer is a single layer and is provided as the outermost surface layer. The binder resin contained polyarylate resin (1), (2) or (3). The additive was a compound represented by the general formula (4). The elastic power of the photosensitive layer was 47.0% or more. As shown in Table 1, with respect to the photoreceptors (A-1) to (A-12), the filming resistance was evaluation A (good) or evaluation B (particularly good).

  In the photoreceptors (B-1) and (B-3) to (B-5), the charge transport layer contained any one of polyarylate resins (R-B1) to (R-B4). The polyarylate resins (R-B1) to (R-B4) were not polyarylate resins represented by the general formula (1), (2) or (3). The photoreceptor (B-2) did not contain the additive (4). In each of the photoreceptors (B-1) to (B-5), the elastic power of the photosensitive layer was less than 47.0%. As shown in Table 1, in each of the photoreceptors (B-1) to (B-5), the evaluation of filming resistance was all evaluation C (defect).

  From the above, it was shown that the photoreceptor according to the present invention is excellent in filming resistance. In addition, it has been shown that the image forming apparatus according to the present invention suppresses the occurrence of image defects due to filming.

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

DESCRIPTION OF SYMBOLS 30 Photoconductor 31 Conductive base | substrate 32 Photosensitive layer 32a Surface 321 Charge generation layer 322 Charge transport layer 42 Charging part 44 Exposure part 46 Development part 48 Transfer part 100 Image forming apparatus M Recording medium

Claims (17)

An electrophotographic photosensitive member comprising a conductive substrate and a photosensitive layer,
The photosensitive layer includes 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 an additive, and the charge transport layer is a single layer and is provided as an outermost surface layer,
The binder resin includes a polyarylate resin represented by the general formula (1), (2) or (3),
The additive includes a compound represented by the general formula (4),
An electrophotographic photosensitive member, wherein the photosensitive layer has an elastic power of 47.0% or more.

In the general formula (1),
X ¹ and Y ¹ each represent a divalent group represented by the chemical formula (A), (B), (C), (D), (E) or (F), and X ¹ and Y ¹ Are different from each other
kr and kt each independently represent 2 or 3,
r ¹ and s ¹ each independently represent a positive number satisfying the formulas (1a) and (1b),
t ¹ and u ¹ each independently represents a number of 0 or more that satisfies the mathematical formulas (1a) and (1b).
r ¹ + s ¹ + t ¹ + u ¹ = 100 (1a)
r ¹ + t ¹ = s ¹ + u ¹ (1b)

In the general formula (2),
R ²¹ , R ²² , R ²³ and R ²⁴ each independently represents a hydrogen atom or a methyl group,
X ² and Y ² each represent a divalent group represented by the chemical formula (A), (B), (C), (D), (E) or (F), and X ² and Y ² Are different from each other,
r ² , s ² , t ² and u ² each independently represent a positive number satisfying the mathematical expressions (2a), (2b) and (2c).
r ² + s ² + t ² + u ² = 100 (2a)
r ² + t ² = s ² + u ² (2b)
0.30 ≦ s ² / (s ² + u ² ) ≦ 0.70 (2c)

In the general formula (3),
R ³¹ , R ³² , R ³³ and R ³⁴ each independently represents a hydrogen atom or a methyl group,
X ³ and Y ³ each represent a divalent group represented by the chemical formula (A), (B), (C), (D), (E) or (F), and X ³ and Y ³ Are different from each other,
r ³ , s ³ , t ³ and u ³ each independently represent a positive number satisfying the mathematical expressions (3a), (3b) and (3c).
r ³ + s ³ + t ³ + u ³ = 100 (3a)
r ³ + t ³ = s ³ + u ³ (3b)
0.30 ≦ s ³ / (s ³ + u ³ ) ≦ 0.70 (3c)

In the general formula (4),
R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms which may have a halogen atom, or 7 to 20 carbon atoms. Represents the following aralkyl group,
R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ may each independently have a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. A good aryl group having 6 to 14 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an amino group or a nitro group which may have a phenyl group,
Of R ³ , R ⁴ , R ⁵ and R ⁶ , two substituents bonded to adjacent carbon atoms in the benzene ring may be bonded to each other to form an aromatic ring,
Of R ⁷ , R ⁸ , R ⁹ and R ¹⁰ , two substituents bonded to adjacent carbon atoms in the benzene ring may be bonded to each other to form an aromatic ring.   The electrophotographic photosensitive member according to claim 1, wherein a scratch depth of the photosensitive layer is 0.50 μm or less. Is the polyarylate resin represented by the general formula (1) a polyarylate resin represented by the general formula (1-1), (1-2), (1-3) or (1-4)? A polyarylate resin represented by the chemical formula (1-5) or (1-6),
The polyarylate resin represented by the general formula (2) is a polyarylate resin represented by the general formula (2-1),
The electrophotographic photosensitive member according to claim 1, wherein the polyarylate resin represented by the general formula (3) is a polyarylate resin represented by the general formula (3-1).

In the general formulas (1-1), (1-2), (1-3) and (1-4), r ¹¹ , s ¹¹ , t ¹¹ and u ¹¹ are each independently represented by the formula (1a ′) , (1b ′) and a positive number satisfying (1c).
r ¹¹ + s ¹¹ + t ¹¹ + u ¹¹ = 100 (1a ′)
r ¹¹ + t ¹¹ = s ¹¹ + u ¹¹ (1b ′)
0.30 ≦ s ¹¹ / (s ¹¹ + u ¹¹ ) ≦ 0.70 (1c)

In the general formula (2-1), r ² , s ² , t ² and u ² each independently represent a positive number satisfying the mathematical formulas (2a), (2b) and (2c).

In the general formula (3-1), r ³ , s ³ , t ³ and u ³ each independently represent a positive number satisfying the formulas (3a), (3b) and (3c).   The electrophotographic photosensitive member according to claim 3, wherein the binder resin includes a polyarylate resin represented by the general formula (1-1).   The electrophotographic photosensitive member according to claim 3, wherein the binder resin includes a polyarylate resin represented by the general formula (1-2).   The electrophotographic photosensitive member according to claim 3, wherein the binder resin includes a polyarylate resin represented by the general formula (1-6).   The electrophotographic photosensitive member according to claim 3, wherein the binder resin includes a polyarylate resin represented by the general formula (2-1).   The electrophotographic photosensitive member according to claim 3, wherein the binder resin includes a polyarylate resin represented by the general formula (3-1). The electrophotographic photoreceptor according to any one of claims 1 to 8, wherein the hole transport agent comprises a compound represented by the general formula (10) or (11).

In the general formula (10), R ¹⁰¹ , R ¹⁰² , R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ and R ¹⁰⁶ are each independently an alkyl group having 1 to 8 carbon atoms, a phenyl group, or 1 or more carbon atoms. Represents 8 or less alkoxy groups,
k, l, m and n each independently represent an integer of 0 to 5,
p and q each independently represent an integer of 0 or more and 4 or less.

In the general formula (11), R ¹¹¹ , R ¹¹² , R ¹¹³ , R ¹¹⁴ , R ¹¹⁵ and R ¹¹⁶ are each independently a halogen atom or a carbon atom having 1 to 6 carbon atoms which may have a substituent. Represents an alkyl group, an alkoxy group having 1 to 6 carbon atoms which may have a substituent, or an aryl group having 6 to 14 carbon atoms which may have a substituent,
a represents an integer of 1 to 3,
d, e, f, g, h and i each independently represent an integer of 0 or more and 5 or less,
When d represents an integer of 2 or more and 5 or less, the plurality of R ¹¹¹ may be the same or different. When e represents an integer of 2 or more and 5 or less, the plurality of R ¹¹² may be the same or different. When R represents an integer of 2 or more and 5 or less, the plurality of R ¹¹³ may be the same or different, and when g represents an integer of 2 or more and 5 or less, the plurality of R ¹¹⁴ may be the same or different, and h is 2 or more When R represents an integer of 5 or less, the plurality of R ¹¹⁵ may be the same or different, and when i represents an integer of 2 or more and 5 or less, the plurality of R ¹¹⁶ may be the same or different. The electrophotographic photosensitive member according to claim 9, wherein the hole transport agent includes a compound represented by chemical formula (10-1) or (11-1).

In the general formula (4),
R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a phenyl group that may have a halogen atom,
R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently have one or more hydrogen atoms, alkyl groups having 1 to 6 carbon atoms, or phenyl groups. The electrophotographic photosensitive member according to any one of claims 1 to 10, which represents an amino group that may be substituted. The additive according to any one of claims 1 to 11, represented by a chemical formula (4-1), a chemical formula (4-2), a chemical formula (4-3), or a chemical formula (4-4). Electrophotographic photoreceptor.

  A process cartridge comprising the electrophotographic photosensitive member according to claim 1. An image forming apparatus comprising the electrophotographic photosensitive member according to any one of claims 1 to 12, a charging unit, an exposure unit, a developing unit, and a transfer unit,
The charging unit charges the surface of the electrophotographic photosensitive member to a negative polarity,
The exposing unit exposes the charged surface of the electrophotographic photosensitive member to form an electrostatic latent image on the surface of the electrophotographic photosensitive member;
The developing unit develops the electrostatic latent image as a toner image,
The transfer unit is an image forming apparatus that transfers the toner image from the electrophotographic photosensitive member to a transfer target. The transfer object is a recording medium,
The image forming apparatus according to claim 14, wherein the electrophotographic photosensitive member is in contact with the recording medium when the transfer unit transfers the toner image from the electrophotographic photosensitive member to the recording medium.   The image forming apparatus according to claim 14, wherein the developing unit cleans the surface of the electrophotographic photosensitive member.   The image forming apparatus according to claim 14, wherein the charging unit is a charging roller.

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