JP6503667B2 - Electrophotographic photosensitive member, process cartridge, and image forming apparatus - Google Patents

Description

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

  In Patent Document 1, a positively charged single-layer electrophotographic image used as an image carrier in an image forming apparatus including an image carrier, a charging device of a contact charging type, an exposure device, a developing device, and a transfer device. A positively charged single-layer electrophotographic photosensitive member, which is a photosensitive member, and wherein the binder resin contained in the photosensitive layer contains a polycarbonate resin containing 35 to 50% by mass of a repeating unit having a biphenyl structure. It is disclosed.

  Patent Document 2 shows an electrophotographic photosensitive member in which a photosensitive layer containing a charge generating agent, a charge transporting agent and a binder resin is provided on a conductive substrate, and the binder resin is a repeating unit having a biphenyl structure. An electrophotographic photosensitive member is disclosed, which is a polycarbonate resin containing 40 to 100 mol%.

JP, 2011-209500, A JP 2005-331735 A

  The object of the present invention is to provide a binder resin, at least one charge generating material selected from hydroxygallium phthalocyanine pigments and chlorogallium phthalocyanine pigments, and a hole transporting material represented by the general formula (2) and the general formula (3) In the photosensitive layer containing an electron transporting material represented by the following, the image carrier can be compared to the case where only a binder resin consisting of a structural unit whose m in the general formula (1) is 10 is used as a binder resin. It is an object of the present invention to provide an electrophotographic photosensitive member which is less likely to generate a color point generated on an image when charged with a high charging voltage.

The above-mentioned subject is solved by the following means. That is,
<1>
A conductive substrate,
A single-layer type photosensitive layer provided on the conductive substrate, which is selected from a binder resin containing a structural unit represented by the following general formula (1), a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment A photosensitive layer containing at least one charge generating material, a hole transporting material represented by the following general formula (2), and an electron transporting material represented by the following general formula (3):
An electrophotographic photosensitive member having

(In the general formula (1), m and n represent a copolymerization molar ratio, m is 15 or more and 25 or less, n is 75 or more and 85 or less, and m + n = 100.)

(In general formula (2), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom, or A lower alkyl group, a lower alkoxy group and a phenyl group which may have a substituent selected from a halogen atom, and p and q each independently represent 0 or 1)

(In general formula (3), R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, R ¹⁸ represents an alkyl group, -L ¹⁹ -O-R ²⁰ , an aryl group or an aralkyl group, provided that L ¹⁹ represents an alkylene group, and R ²⁰ represents an alkyl group.

<2>
The electrophotographic photosensitive member according to <1> , wherein a viscosity average molecular weight of the binder resin is 50,000 or more and 70,000 or less.

<3>
The electrophotographic photosensitive member according to <1> or <2> , wherein the charge generation material is a V-type hydroxygallium phthalocyanine pigment.

<4>
The electrophotographic photosensitive member according to any one of <1> to <3> , wherein the hole transport material is a hole transport material in which p and q in the general formula (2) both represent 1. .

<5>
The electron transport material is an electron transport material wherein R ¹⁸ in the general formula (3) represents an aralkyl group or a branched alkyl group having 5 to 10 carbon atoms, any one of <1> to <4> An electrophotographic photosensitive member according to item 1.

<6>
The electrophotographic photosensitive member according to any one of <1> to <5> .
Process cartridge to be attached to and removed from the image forming apparatus.

<7>
An electrophotographic photosensitive member according to any one of <1> to <5> ,
Charging means for charging the surface of the electrophotographic photosensitive member;
Electrostatic latent image forming means for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member charged;
Developing means for developing an electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image;
A transfer unit that transfers the toner image to the surface of a recording medium;
An image forming apparatus comprising:

According to the invention of <1> , at least one charge generating material selected from a binder resin, a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment, and a hole transporting material represented by the general formula (2) and the like In the photosensitive layer containing the electron transporting material represented by the formula (3), compared to the case where only a binder resin consisting of a structural unit in which m in the general formula (1) is 10 is used as the binder resin: Provided is an electrophotographic photosensitive member which is less likely to generate a color point generated on an image when the image carrier is charged with a high charging voltage.

According to the invention of <2> , the image carrier is highly charged as compared with the case where only the binder resin comprising the structural unit represented by the above general formula (1) having a viscosity average molecular weight of 40,000. Provided is an electrophotographic photosensitive member which is less likely to generate a color point generated on an image when charged by a voltage.

According to the invention relating to <3> , an electrophotographic photosensitive member having high sensitivity as compared with the case where only the chlorogallium phthalocyanine pigment used in Example 16 is used as the charge generation material is provided.

According to the invention relating to <4> , an electrophotographic photosensitive member having high sensitivity as compared with the case where only the hole transport material (HTM 6) used in Example 17 is used as the hole transport material is provided.

According to the invention which concerns on <5> , compared with the case where only the electron transport material (ETM5) used in Example 14 is used as an electron transport material, an electrophotographic photosensitive member with high sensitivity is provided.

According to the invention of <6> or <7> , at least one charge generating material selected from a binder resin, a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment and a hole represented by the general formula (2) In the photosensitive layer containing the transport material and the electron transport material represented by the general formula (3), only the binder resin comprising a structural unit in which m in the general formula (1) is 10 is used as the binder resin. There is provided a process cartridge or an image forming apparatus provided with an electrophotographic photosensitive member in which a color point generated on an image is less likely to occur when the image carrier is charged with a high charging voltage as compared with the case where the electrophotographic photosensitive member is applied.

FIG. 1 is a schematic partial cross-sectional view showing an electrophotographic photosensitive member according to the present embodiment. FIG. 1 is a schematic configuration view showing an image forming apparatus according to the present embodiment. FIG. 6 is a schematic configuration view showing an image forming apparatus according to another embodiment of the present invention.

  Hereinafter, an embodiment which is an example of the present invention will be described.

[Electrophotographic photosensitive member]
The electrophotographic photosensitive member according to the present embodiment is a positively charged organic photosensitive member having a conductive substrate and having a single-layered photosensitive layer on the conductive substrate (hereinafter simply referred to as “photosensitive member” or “single-layered photosensitive member Sometimes referred to as
The single-layer type photosensitive layer comprises a binder resin containing the structural unit represented by the general formula (1) (hereinafter sometimes referred to as "specific polycarbonate resin"), a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment And at least one charge-generating material (hereinafter sometimes referred to as “specific phthalocyanine pigment”) selected from the group consisting of: a hole transport material represented by the general formula (2) (hereinafter “specific hole transport material”; And an electron transporting material represented by the general formula (3) (hereinafter sometimes referred to as "specific electron transporting material").
The single-layer type photosensitive layer is a photosensitive layer having hole transportability and electron transportability as well as charge generation capability.

A single-layer type photosensitive member using a specific phthalocyanine pigment as a charge generation material, a specific hole transport material as a hole transport material, and a specific electron transport material as an electron transport material achieves high sensitivity, but a point on an image Color points may occur. The color point on the image is more likely to be generated by an image formed under a high charging voltage (for example, under a charging voltage of 800 V) for the purpose of improving the image quality.
On the other hand, in the present embodiment, the specific polycarbonate resin is used as the binder resin, and the specific phthalocyanine pigment, the specific hole transport material, and the specific electron transport material are used, so the color point on the image is unlikely to occur. . Although the reason is not clear, it is guessed as follows.

  Color points are more likely to occur when both mechanical (electrical stress) and electrical (electrical) stress on the photoreceptor are strong. Specifically, for example, strong mechanical addition due to contact of another member or the like is applied, and further strong electrical addition due to high electrification voltage is applied thereto, thereby causing a crack (crack) in the photosensitive layer, resulting therefrom It is believed that color points appear on the image.

  On the other hand, in the present embodiment, a specific polycarbonate resin is used as the binder resin. The specific polycarbonate resin is more resistant to mechanical load than resins other than polycarbonate resins, and is more resistant to electric load than polycarbonate resins containing structural units in which m in the general formula (1) is out of the above range. Even resistance is high. Furthermore, since the specific carbonate resin has high affinity to the specific phthalocyanine pigment, the dispersibility of the specific phthalocyanine pigment in the specific carbonate resin is enhanced. Therefore, in the present embodiment, it is presumed that the photosensitive layer is less likely to be cracked and the color point on the image is less likely to be generated even if both mechanical addition and electrical addition are applied strongly.

Moreover, in the present embodiment, it is desirable that the viscosity average molecular weight of the specific polycarbonate resin is 50,000 or more and 70,000 or less.
By using a specific polycarbonate resin having a viscosity average molecular weight within the above range, color points on the image are less likely to be generated as compared with the case where a specific polycarbonate resin having a viscosity average molecular weight smaller than the above range is used. Although the reason is not clear, it is presumed that the specific polycarbonate resin having a viscosity average molecular weight within the above range is more resistant to mechanical addition than the specific polycarbonate resin having a viscosity average molecular weight smaller than the above range. Be done.

  In addition, by using a specific polycarbonate resin having a viscosity average molecular weight within the above range, a photosensitive member with less unevenness in the film thickness of the photosensitive layer is obtained as compared to the case where a specific polycarbonate resin having a viscosity average molecular weight larger than the above range is used. And the productivity of the photoreceptor is good. Although the reason is not clear, the specific polycarbonate resin having a viscosity average molecular weight within the above range has a viscosity smaller than that of the specific polycarbonate resin having a viscosity average molecular weight larger than the above range, and a single layer type photosensitive layer It is presumed that sagging and the like during film formation are unlikely to occur.

Here, as a method of measuring the viscosity average molecular weight Mv, for example, the following one-point measurement method is used. Specifically, for example, 1 g of resin is first dissolved in 100 cm ³ of methylene chloride, and the specific viscosity sp sp is measured using a Ubbelohde viscometer under a measurement environment of 25 ° C. Next, the limiting viscosity [η] (cm ³ / g) is determined from the relational expression of “ηsp / c = [η] +0.45 [η] ² c” (where c is the concentration (g / cm ³ ) and Moreover, determining the viscosity average molecular weight Mv by the equation "[η] = 1.23 × ¹⁰ -4 ^{Mv 0.83"} as given by H.Schnell.

Hereinafter, the electrophotographic photosensitive member according to the present embodiment will be described in detail with reference to the drawings.
FIG. 1 schematically shows a cross section of a part of an electrophotographic photosensitive member 10 according to the present embodiment.
The electrophotographic photosensitive member 10 shown in FIG. 1 includes, for example, a conductive substrate 3, and an undercoat layer 1 and a single-layered photosensitive layer 2 are provided in this order on the conductive substrate 3. There is.
The undercoat layer 1 is a layer provided as necessary. That is, the single-layer type photosensitive layer 2 may be provided directly on the conductive substrate 3 or may be provided via the undercoat layer 1.
Also, other layers may be provided as necessary. Specifically, for example, if necessary, a protective layer may be provided on the single-layer photosensitive layer 2.

  Hereinafter, each layer of the electrophotographic photosensitive member according to the present embodiment will be described in detail. In addition, the code | symbol is abbreviate | omitted and demonstrated.

(Conductive substrate)
As the conductive substrate, for example, a metal plate containing metal (aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum etc.) or alloy (stainless steel etc.), metal drum, metal belt etc. Can be mentioned. In addition, as the conductive substrate, for example, paper coated with a conductive compound (eg, conductive polymer, indium oxide etc.), metal (eg, aluminum, palladium, gold etc.) or alloy, vapor deposition or lamination, resin film, belt etc. Can also be mentioned. Here, “conductive” means that the volume resistivity is less than 10 ¹³ Ωcm.

  When the electrophotographic photosensitive member is used for a laser printer, the surface of the conductive substrate has a center line average roughness Ra of not less than 0.04 μm and not more than 0.5 μm for the purpose of suppressing interference fringes generated when irradiating a laser beam. It is preferable to be roughened below. In the case where non-interference light is used as a light source, roughening for preventing interference fringes is not particularly required, but it is more suitable for prolonging the life to suppress generation of defects due to unevenness on the surface of the conductive substrate.

  As a method of surface roughening, for example, wet honing performed by suspending an abrasive in water and spraying it onto a support, centerless grinding in which a conductive substrate is pressed against a rotating grindstone and grinding is continuously performed, Anodizing treatment etc. are mentioned.

  As a method of roughening, conductive or semiconductive powder is dispersed in a resin without roughening the surface of the conductive substrate to form a layer on the surface of the conductive substrate, and A method of roughening with particles dispersed in a layer may also be mentioned.

  In the surface roughening treatment by anodizing, an oxide film is formed on the surface of a conductive substrate by anodizing in a electrolytic solution using a metal (for example, aluminum) conductive substrate as an anode. Examples of the electrolyte solution include a sulfuric acid solution and an oxalic acid solution. However, the porous anodic oxide film formed by anodic oxidation is chemically active as it is, easily polluted, and has a large resistance fluctuation due to the environment. Therefore, for the porous anodic oxide film, the fine pores of the oxide film are blocked by volume expansion due to hydration reaction with pressurized steam or boiling water (a metal salt such as nickel may be added), and more stable hydrated oxidation It is preferable to carry out the sealing process which changes into a thing.

  The thickness of the anodic oxide film is preferably, for example, 0.3 μm or more and 15 μm or less. When the film thickness is in the above range, the barrier property against injection tends to be exhibited, and the increase in residual potential due to repeated use tends to be suppressed.

The conductive substrate may be treated with an acid treatment liquid or boehmite treatment.
The treatment with the acid treatment solution is carried out, for example, as follows. First, an acidic treatment solution containing phosphoric acid, chromic acid and hydrofluoric acid is prepared. The blending ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acid treatment solution is, for example, 10% by mass to 11% by mass of phosphoric acid, 3% by mass to 5% by mass of chromic acid, and hydrofluoric acid The total concentration of these acids is preferably in the range of 13.5 mass% to 18 mass% in the range of 0.5 mass% to 2 mass%. The processing temperature is preferably, for example, 42 ° C. or more and 48 ° C. or less. The film thickness of the film is preferably 0.3 μm or more and 15 μm or less.

  The boehmite treatment is performed, for example, by immersing in pure water of 90 ° C. to 100 ° C. for 5 minutes to 60 minutes, or by bringing the substrate into contact with heated steam of 90 ° C. to 120 ° C. for 5 minutes to 60 minutes. The film thickness of the film is preferably 0.1 μm to 5 μm. This is further anodized using an electrolyte solution with low film solubility such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, citrate and the like. Good.

(Sublayer)
The undercoat layer is, for example, a layer containing inorganic particles and a binder resin.

Examples of the inorganic particles include inorganic particles having a powder resistance (volume resistivity) of 10 ² Ωcm or more and 10 ¹¹ Ωcm or less.
Among these, as the inorganic particles having the above-mentioned resistance value, metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles are preferable, and zinc oxide particles are particularly preferable.

The specific surface area of the inorganic particles according to the BET method is, for example, 10 m ² / g or more.
The volume average particle diameter of the inorganic particles is, for example, 50 nm or more and 2000 nm or less (preferably 60 nm or more and 1000 nm or less).

  The content of the inorganic particles is, for example, preferably 10% by mass to 80% by mass, and more preferably 40% by mass to 80% by mass, with respect to the binder resin.

  The inorganic particles may be subjected to surface treatment. The inorganic particles may be used as a mixture of two or more kinds of particles different in surface treatment or different in particle diameter.

  As a surface treating agent, a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, surfactant etc. are mentioned, for example. In particular, a silane coupling agent is preferable, and a silane coupling agent having an amino group is more preferable.

  As a silane coupling agent having an amino group, for example, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-amino Examples include, but are not limited to, propylmethyldimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, and the like.

  You may use a silane coupling agent in mixture of 2 or more types. For example, a silane coupling agent having an amino group may be used in combination with another silane coupling agent. Other silane coupling agents include, for example, vinyltrimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glylic Cidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- ( Aminoethyl) -3-aminopropylmethyldimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, etc., but is limited thereto It is not a thing.

  The surface treatment method using the surface treatment agent may be any known method, and may be either a dry method or a wet method.

  The processing amount of the surface treatment agent is preferably, for example, 0.5% by mass or more and 10% by mass or less with respect to the inorganic particles.

  Here, the undercoat layer preferably contains the electron accepting compound (acceptor compound) together with the inorganic particles, from the viewpoint of enhancing the long-term stability of the electrical characteristics and the carrier blocking property.

Examples of the electron accepting compound include quinone compounds such as chloranil and bromoanil; tetracyanoquinodimethane compounds; 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone and the like 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4- Oxadiazole compounds such as oxadiazole and 2,5-bis (4-diethylaminophenyl) -1,3,4 oxadiazole; xanthone compounds; thiophene compounds; 3,3 ', 5,5'tetra- Examples include diphenoquinone compounds such as t-butyl diphenoquinone; electron transporting substances such as, and the like.
In particular, as the electron accepting compound, a compound having an anthraquinone structure is preferable. As the compound having an anthraquinone structure, for example, a hydroxyanthraquinone compound, an aminoanthraquinone compound, an aminohydroxyanthraquinone compound and the like are preferable, and specifically, for example, anthraquinone, alizarin, quinizarin, anthralphine, and purpurin are preferable.

  The electron accepting compound may be contained in the undercoat layer in a dispersed state with the inorganic particles, or may be contained in a state of being attached to the surface of the inorganic particles.

  Examples of the method for attaching the electron accepting compound to the surface of the inorganic particles include a dry method and a wet method.

  In the dry method, for example, while stirring the inorganic particles with a mixer with large shear force, the electron accepting compound in which the electron accepting compound is dissolved directly or in an organic solvent is dropped, and is sprayed together with dry air or nitrogen gas to make the electron accepting compound It is a method of adhering to the surface of inorganic particles. When dropping or spraying the electron accepting compound, it is preferable to carry out at a temperature equal to or lower than the boiling point of the solvent. After dropping or spraying the electron accepting compound, baking may be further performed at 100 ° C. or higher. Baking is not particularly limited as long as the temperature and time at which electrophotographic characteristics can be obtained.

  In the wet method, for example, while dispersing inorganic particles in a solvent by stirring, ultrasonic waves, sand mill, attritor, ball mill etc., an electron accepting compound is added, stirred or dispersed, and then the solvent is removed to obtain an electron. It is a method of attaching a receptive compound to the surface of an inorganic particle. The solvent removal method is distilled off, for example, by filtration or distillation. After solvent removal, baking may be further performed at 100 ° C. or higher. Baking is not particularly limited as long as the temperature and time at which electrophotographic characteristics can be obtained. In the wet method, the water content of the inorganic particles may be removed before adding the electron accepting compound, and examples thereof include a method of removing while stirring and heating in a solvent, and a method of removing azeotropically with a solvent It can be mentioned.

  The adhesion of the electron accepting compound may be performed before or after the inorganic particles are subjected to surface treatment with a surface treatment agent, and may be performed simultaneously with the adhesion of the electron accepting compound and the surface treatment with the surface treatment agent.

  The content of the electron accepting compound is, for example, preferably 0.01% by mass to 20% by mass, and preferably 0.01% by mass to 10% by mass, with respect to the inorganic particles.

Examples of the binder resin used for the undercoat layer include acetal resin (for example, polyvinyl butyral etc.), polyvinyl alcohol resin, polyvinyl acetal resin, casein resin, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, unsaturated polyester Resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, urea resin, phenol resin, phenol-formaldehyde resin, melamine resin, Known polymer compounds such as urethane resin, alkyd resin, epoxy resin, etc .; zirconium chelate compound; titanium chelate compound; aluminum chelate compound; titanium alkoxide compound ; Organic titanium compounds; known materials silane coupling agent, and the like.
Examples of the binder resin used for the undercoat layer also include a charge transporting resin having a charge transporting group, a conductive resin (for example, polyaniline and the like), and the like.

Among these, as the binder resin used in the undercoat layer, resins insoluble in the coating solvent of the upper layer are preferable, and in particular, urea resin, phenol resin, phenol-formaldehyde resin, melamine resin, urethane resin, unsaturated polyester Thermosetting resin such as resin, alkyd resin, epoxy resin; and at least one resin selected from the group consisting of polyamide resin, polyester resin, polyether resin, methacrylic resin, acrylic resin, polyvinyl alcohol resin and polyvinyl acetal resin Resins obtained by reaction with curing agents are preferred.
When two or more of these binder resins are used in combination, the mixing ratio thereof is set as necessary.

The undercoat layer may contain various additives to improve the electrical properties, the environmental stability, and the image quality.
Examples of the additive include known materials such as polycyclic condensation type and electron transporting pigments such as azo type, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, and silane coupling agents. Be The silane coupling agent is used for surface treatment of the inorganic particles as described above, but may be further added to the undercoat layer as an additive.

  As a silane coupling agent as an additive, for example, vinyltrimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3- Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- Examples include (aminoethyl) -3-aminopropylmethylmethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane and the like.

  As a zirconium chelate compound, for example, zirconium butoxide, ethyl zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate zirconium butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octanoate, Examples thereof include zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Examples of titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt And titanium lactate, titanium lactate ethyl ester, titanium triethanolaminate, polyhydroxy titanium stearate and the like.

  Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate, diethylacetoacetate aluminum diisopropylate, aluminum tris (ethylacetoacetate) and the like.

  These additives may be used alone or as a mixture or polycondensate of a plurality of compounds.

The undercoat layer preferably has a Vickers hardness of 35 or more.
The surface roughness (ten-point average roughness) of the undercoat layer is adjusted from 1 / 4n (n is the refractive index of the upper layer) to 1 / 2λ of the exposure laser wavelength λ used for moire image suppression It is good to be done.
Resin particles and the like may be added to the undercoat layer to adjust the surface roughness. Examples of the resin particles include silicone resin particles and crosslinked polymethyl methacrylate resin particles. In addition, the surface of the undercoat layer may be polished to adjust the surface roughness. The polishing method may, for example, be buffing, sand blasting, wet honing or grinding.

  The formation of the undercoat layer is not particularly limited, and a known formation method is used. For example, a coating film of the undercoat layer forming solution obtained by adding the above components to a solvent is formed, and the coating film is dried. And by heating if necessary.

As a solvent for preparing the coating liquid for undercoat layer formation, known organic solvents such as alcohol solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone solvents, ketone alcohol solvents, ether solvents Solvents, ester solvents and the like can be mentioned.
Specific examples of these solvents include methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, Common organic solvents such as n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, toluene and the like can be mentioned.

  Examples of the method of dispersing the inorganic particles when preparing the coating liquid for forming the undercoat layer include known methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill and a paint shaker.

  As a method of applying the coating liquid for undercoat layer formation on a conductive substrate, for example, blade coating method, wire bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating method Etc. can be mentioned.

  The thickness of the undercoat layer is, for example, preferably in the range of 15 μm or more, more preferably 20 μm to 50 μm.

(Intermediate layer)
Although not shown, an intermediate layer may be further provided between the undercoat layer and the photosensitive layer.
The intermediate layer is, for example, a layer containing a resin. Examples of the resin used for the intermediate layer include acetal resin (eg, polyvinyl butyral etc.), polyvinyl alcohol resin, polyvinyl acetal resin, casein resin, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, Polymer compounds such as polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin and the like can be mentioned.
The intermediate layer may be a layer containing an organometallic compound. Examples of the organic metal compound used for the intermediate layer include organic metal compounds containing metal atoms such as zirconium, titanium, aluminum, manganese and silicon.
The compounds used in these intermediate layers may be used alone or as a mixture or polycondensate of a plurality of compounds.

  Among these, the intermediate layer is preferably a layer containing an organic metal compound containing a zirconium atom or a silicon atom.

The formation of the intermediate layer is not particularly limited, and a known formation method is used. For example, a coating film of the coating liquid for forming an intermediate layer in which the above components are added to a solvent is formed, and the coating film is dried. It does by heating according to.
As a coating method for forming the intermediate layer, a usual method such as a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method or a curtain coating method is used.

  The film thickness of the intermediate layer is preferably set, for example, in the range of 0.1 μm to 3 μm. The intermediate layer may be used as a subbing layer.

(Single-layer type photosensitive layer)
The single-layer type photosensitive layer contains a binder resin, a charge generation material, a hole transport material, and an electron transport material, and may contain other additives as required.

-Binding resin-
As a binder resin, a specific polycarbonate resin containing a structural unit represented by the following general formula (1) is used.

In the general formula (1), m and n represent a copolymerization molar ratio, m is 15 or more and 25 or less, n is 75 or more and 85 or less, and m + n = 100.
As for m in General formula (1), 20 or more and 25 or less are preferable.
The specific polycarbonate resin may contain other structural units in addition to the structural unit represented by the general formula (1). However, 90 mass% or more is preferable, as for the ratio of the structural unit represented by the said General formula (1) with respect to whole specific polycarbonate resin, 95 mass% or more is more preferable, and it is especially preferable not to contain another structural unit.
In addition, the specific polycarbonate resin containing the structural unit represented by General formula (1) should just have 2 types of units in said General formula (1) by the molar ratio of m: n, and said 2 types Other structural units may be included between the units of (1), and other structural units may be included at the end of the specific polycarbonate resin.

  The specific polycarbonate resin is, for example, a compound represented by the following structural formula (4) or the like, and a compound represented by the following structural formula (5) (and other compounds as needed), and carbonic acid ester formation such as phosgene The compound is synthesized by a method such as polycondensation with an organic compound or transesterification with a bisaryl carbonate.

  As a viscosity average molecular weight of specific polycarbonate resin, 20,000 or more and 100,000 or less are mentioned, for example, 40,000 or more and 80,000 or less are preferable, 50,000 or more and 70,000 or less are more preferable.

The specific polycarbonate resin may be used singly or in combination of two or more. In addition, resins other than the specific polycarbonate resin (i.e., other polycarbonate resins, other resins, etc.) may be contained as a binder resin component within the range that does not impair the purpose of the present embodiment.
In addition, as content in the case of containing resin other than specific polycarbonate resin, the range of 25 mass% or less is mentioned with respect to the whole binder resin, for example.

  As resins other than the specific polycarbonate resin, for example, polycarbonate resin in which m in the general formula (1) is out of the above range, other polycarbonate resin such as bisphenol A, polyester resin, polyarylate resin, methacrylic resin, acrylic resin, Polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride Copolymers, silicone resins, silicone alkyd resins, phenol-formaldehyde resins, styrene-alkyd resins, poly-N-vinylcarbazole, polysilanes and the like can be mentioned.

The content of the binder resin with respect to the total solid content of the photosensitive layer is, for example, 35% by mass or more and 60% by mass or less, desirably 45% by mass or more and 55% by mass or less.
In addition, when content of this binder resin is used together 2 or more types of binder resin, it is content of the whole those binder resin.

-Charge generation material-
As the charge generation material, at least one selected from a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment is applied.
As the charge generating material, these pigments may be used alone, but may be used in combination as needed. As the charge generation material, a hydroxygallium phthalocyanine pigment is preferable from the viewpoint of increasing the sensitivity of the photosensitive member and suppressing the generation of color point of an image.

The hydroxygallium phthalocyanine pigment is not particularly limited, but a V-type hydroxygallium phthalocyanine pigment is more preferable from the viewpoint of increasing the sensitivity of the photosensitive member and suppressing the generation of color point of an image.
In particular, as a hydroxygallium phthalocyanine pigment, for example, in a spectral absorption spectrum in a wavelength range of 600 nm to 900 nm, a hydroxygallium phthalocyanine pigment having a maximum peak wavelength in a range of 810 nm to 839 nm can be obtained more excellently Desirable from the viewpoint. When used as a material of an electrophotographic photosensitive member, excellent dispersibility and sufficient sensitivity, chargeability and dark decay characteristics are easily obtained.

The hydroxygallium phthalocyanine pigment having a maximum peak wavelength in the range of 810 nm to 839 nm described above preferably has an average particle diameter in a specific range and a BET specific surface area in a specific range. Specifically, the average particle diameter is desirably 0.20 μm or less, and more desirably 0.01 μm or more and 0.15 μm or less. On the other hand, the BET specific surface area is desirably 45 m ² / g or more, more desirably 50 m ² / g or more, and particularly desirably 55 m ² / g or more and 120 m ² / g or less. The average particle size is a value measured by a laser diffraction scattering type particle size distribution measuring apparatus (LA-700, manufactured by Horiba, Ltd.) with a volume average particle size (d50 average particle size). Further, it is a value measured by a nitrogen substitution method using a BET type specific surface area measuring device (manufactured by Shimadzu Corporation: Flow Soap II 2300).
Here, when the average particle diameter is larger than 0.20 μm, or when the specific surface area value is less than 45 m ² / g, pigment particles may be coarsened or aggregates of pigment particles may be formed. . In addition, defects such as dispersibility, sensitivity, chargeability and dark decay characteristics may easily occur, which may cause image quality defects.

  The maximum particle size (maximum value of the primary particle size) of the hydroxygallium phthalocyanine pigment is preferably 1.2 μm or less, more preferably 1.0 μm or less, and still more preferably 0.3 μm or less. When the maximum particle size exceeds the above range, black spots are likely to occur.

The hydroxygallium phthalocyanine pigment has an average particle size of 0.2 μm or less and a maximum particle size of 1.2 μm or less, from the viewpoint of suppressing density unevenness caused by exposure of the photosensitive member to a fluorescent lamp or the like. The specific surface area value is preferably 45 m ² / g or more.

  The hydroxygallium phthalocyanine pigment has a Bragg angle (2θ ± 0.2 °) of at least 7.3 °, 16.0 °, 24.9 °, 28.0 ° in an X-ray diffraction spectrum using a CuKα characteristic X-ray. It is desirable that it is V-shaped having a diffraction peak at

On the other hand, the chlorogallium phthalocyanine pigment is not particularly limited, but Bragg angles (2θ ± 0.2 °) of 7.4 °, 16.6 °, 25.5, which provide excellent sensitivity as an electrophotographic photosensitive member material. It is desirable to have diffraction peaks at 5 ° and 28.3 °.
The maximum peak wavelength, the average particle size, the maximum particle size, and the specific surface area value of the preferred spectral absorption spectrum of the chlorogallium phthalocyanine pigment are similar to those of the hydroxygallium phthalocyanine pigment.

  The content of the charge generating material relative to the total solid content of the photosensitive layer is preferably 1% by mass to 5% by mass, and more preferably 1.2% by mass to 4.5% by mass.

-Hole transport material-
As the hole transport material, at least a specific hole transport material represented by General Formula (2) is applied.

In the general formula (2), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom, or a lower This represents a phenyl group which may have a substituent selected from an alkyl group, a lower alkoxy group and a halogen atom. p and q are Each independently represents 0 or 1.

Examples of the lower alkyl group represented by R ^{1 to} R ⁶ in the general formula (2) include linear or branched alkyl groups having 1 to 4 carbon atoms, and specific examples thereof include A methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group etc. are mentioned.
Among these, as a lower alkyl group, a methyl group and an ethyl group are preferable.

Examples of the alkoxy group represented by R ^{1 to} R ⁶ in the general formula (2) include an alkoxy group having 1 to 4 carbon atoms, and specifically, a methoxy group, an ethoxy group, a propoxy group, and a butoxy group Etc.

As a halogen atom which R < ¹ > -R < ⁶ > shows in General formula (2), a fluorine atom, a chlorine atom, a bromine atom, an iodine atom etc. are mentioned, for example.

In the general formula (2), examples of the phenyl group represented by R ^{1 to} R ⁶ include unsubstituted phenyl group; phenyl group substituted with lower alkyl group such as p-tolyl group and 2,4-dimethylphenyl group; p -A lower alkoxy-substituted phenyl group such as a methoxyphenyl group; and a halogen-substituted phenyl group such as a p-chlorophenyl group.
As the substituent which substitutes the phenyl group, for example, a lower alkyl group represented by R ¹ to R ^6, an alkoxy group, a halogen atom.

Among specific hole transport materials, hole transport materials in which p and q represent 1 are preferable from the viewpoint of high sensitivity and suppression of color point generation of an image, and in particular, R ^{1 to} R ⁶ are each independently hydrogen atoms And a lower alkyl group or an alkoxy group, and p and q each preferably represent a hole transport material.

  Hereinafter, exemplary compounds of the specific hole transport material are shown, but the present invention is not limited thereto. In addition, the following exemplary compound number is described as an exemplary compound (2-number) below. Specifically, for example, Exemplified Compound 15 is hereinafter described as “exemplified compound (2-15)”.

In addition, the symbol in the said exemplary compound shows the following meaning.
4-Me: methyl substituted by 4-position of phenyl group 3-Me: methyl substituted by 3-position of phenyl group 4-Cl: chlorine atom substituted by 4-position of phenyl group -MeO: methoxy group substituted at 4-position of phenyl group 4-F: fluorine atom substituted at 4-position of phenyl group 4-Pr: propyl group substituted at 4-position of phenyl group 4-PhO : A phenoxy group substituted at 4-position of phenyl group

The specific hole transport materials may be used alone or in combination of two or more. Moreover, you may use hole transport materials other than a specific hole transport material together as needed in the range which does not inhibit the objective of this embodiment.
In addition, as content in the case of containing hole transport materials other than a specific hole transport material, the range of 25 mass% or less is mentioned with respect to the whole hole transport material, for example.

  As other hole transport materials other than the specific hole transport material resin, for example, triarylamine compounds, benzidine compounds, arylalkane compounds, aryl substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds Compounds such as compounds may be mentioned.

  As a specific example of another hole transport material, the compound shown by the following general formula (B-1) and the compound shown by the following general formula (B-2) are mentioned, for example.

In general formula (B-1), R ^B1 represents a hydrogen atom or a methyl group. n11 represents 1 or 2; Ar ^B1 and Ar ^B2 are each independently a substituted or unsubstituted aryl group, —C ₆ H ₄ —C (R ^B3 ) = C (R ^B4 ) (R ^B5 ), or —C ₆ H ₄ —CH = CH— CH = C (R ^B6 ) (R ^B7 ) is shown, and R ^{B3 to} R ^B7 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. As a substituent, a substituted amino group substituted by a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 1 to 3 carbon atoms is shown.

In general formula (B-2), R ^B8 and R ^{B8 ′} may be the same or different, and each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy having 1 to 5 carbon atoms Group. R ^B9 , R ^{B9 ′} , R ^B10 , and R ^{B10 ′} may be the same or different, and each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, the carbon number An amino group substituted with one or more and two or less alkyl groups, a substituted or unsubstituted aryl group, -C ( ^RB11 ) = C ( ^RB12 ) ( ^RB13 ), or -CH = CH-CH = C (R ^B14 ) (R ^B15 ) is shown, and R ^{B11 to} R ^B15 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. m12, m13, n12 and n13 each independently represent an integer of 0 or more and 2 or less.

Here, among the compounds represented by the general formula (B-1) and the compounds represented by the general formula (B-2), in particular, “—C ₆ H ₄ —CH = CH—CH = C (R ^B6 ) ( A compound represented by the general formula (B-1) having R ^B7 ) and a compound represented by the general formula (B-2) having “—CH = CH—CH = C (R ^B14 ) (R ^B15 )” desirable.

The content of the hole transport material relative to the total solid content of the photosensitive layer is preferably 10% by mass to 40% by mass, and more preferably 20% by mass to 35% by mass.
In addition, when content of this hole transport material is used together 2 or more types of hole transport materials, it is content of the whole hole transport material of those.

-Electron transport material-
As the electron transport material, at least a specific electron transport material represented by the following general formula (3) is used.

In the general formula (3), R ¹¹ and R ¹² . R ¹³ . ^{R 14, R 15, R 16} , and ^{R 17} each independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, or aralkyl group. R ¹⁸ represents an alkyl group, -L ¹⁹ -O-R ²⁰ , an aryl group or an aralkyl group. However, L ¹⁹ represents an alkylene group, and R ²⁰ represents an alkyl group.

In the general formula ^(3), the halogen atom represented by R 11 ^{to R 17,} for example, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the alkyl group represented by R ^{11 to} R ¹⁷ in the general formula (3) include linear or branched alkyl groups having 1 to 4 carbon atoms (preferably 1 to 3 carbon atoms), Specifically, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and the like can be mentioned.

Examples of the alkoxy group represented by R ^{11 to} R ¹⁷ in general formula (3) include an alkoxy group having 1 to 4 carbon atoms (preferably 1 to 3 carbon atoms), and specific examples thereof include a methoxy group, Examples include ethoxy, propoxy and butoxy.

In the general formula ^(3), the aryl group represented by R 11 ^{to R 17,} for example, a phenyl group, a tolyl group and the like.
Examples of the aralkyl group represented by R ^{11 to} R ¹⁷ in the general formula (3) include a benzyl group, a phenethyl group and a phenylpropyl group.
Among these, a phenyl group is desirable.

In the general formula (3), the alkyl group represented by R ¹⁸ is, for example, a linear alkyl group having 1 to 10 carbon atoms (preferably 5 to 10 carbon atoms), 3 to 10 carbon atoms (preferably) Is a branched alkyl group having 5 to 10 carbon atoms).
As a linear alkyl group having 1 to 10 carbon atoms, for example, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n -Octyl group, n-nonyl group, n-decyl group etc. are mentioned.
As a branched alkyl group having 3 to 10 carbon atoms, for example, isopropyl group,
Isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, neopentyl group, tert-pentyl group, isohexyl group, sec-hexyl group, tert-hexyl group, isoheptyl group, sec-heptyl group, tert-heptyl group, An isooctyl group, a sec-octyl group, a tert-octyl group, an isononyl group, a sec-nonyl group, a tert-nonyl group, an isodecyl group, a sec-decyl group, a tert-decyl group and the like can be mentioned.

In the general formula ^(3), a group represented by ^-L 19 ^{-O-R 20} represented by ^{R 18 is L 19} represents an alkylene ^{group, R 20} represents an alkyl group.
Examples of the alkylene group represented by L ¹⁹ include a linear or branched alkylene group having 1 to 12 carbon atoms, and a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, an isobutylene Groups, sec-butylene group, tert-butylene group, n-pentylene group, isopentylene group, neopentylene group, tert-pentylene group and the like.
Examples of the alkyl group represented by R ²⁰ include the same groups as the alkyl groups represented by R ^{11 to} R ¹⁷ above.

Examples of the aryl group represented by R ¹⁸ in the general formula (3) include a phenyl group, a methylphenyl group and a dimethylphenyl group.
When R ¹⁸ in the general formula (3) is an aryl group, it is preferable from the viewpoint of solubility that the aryl group is further substituted with an alkyl group. As an alkyl group substituted by the said aryl group, the group similar to the alkyl group which said R < ¹¹ > -R < ¹⁷ > shows is mentioned. Further, specific examples of the aryl group further substituted with an alkyl group include an ethylphenyl group as well as the above methylphenyl group and dimethylphenyl group.

In the general formula (3), examples of the aralkyl group represented by R ¹⁸ include a group represented by -R ²¹ -Ar. ^{However, R 21} represents an alkylene group, Ar represents an aryl group.
Examples of the alkylene group represented by R ²¹ include a linear or branched alkylene group having 1 to 12 carbon atoms, and a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, an isobutylene Groups, sec-butylene group, tert-butylene group, n-pentylene group, isopentylene group, neopentylene group, tert-pentylene group and the like.
Examples of the aryl group represented by Ar include a phenyl group, a methylphenyl group and a dimethylphenyl group ethylphenyl group.

Specific examples of the aralkyl group represented by R ¹⁸ in the general formula (3) include benzyl group, methylbenzyl group, dimethylbenzyl group, phenylethyl group, methylphenylethyl group, phenylpropyl group, phenylbutyl group and the like. .

As specific electron transport materials represented by the general formula (3), from the viewpoint of increasing sensitivity and suppressing image density reduction, an electron having R ¹⁸ having a branched alkyl group or aralkyl group having 5 to 10 carbon atoms A transport material is preferred, and in particular, R ^{11 to} R ¹⁷ each independently represent a hydrogen atom, a halogen atom, or an alkyl group, and R ¹⁸ is a branched alkyl group or aralkyl group having 5 to 10 carbon atoms. The electron transport material shown is preferred.

  Hereinafter, although the exemplary compound of the specific electron transport material represented by General formula (3) is shown, it is not necessarily limited to this. In addition, the following exemplary compound number is described as an exemplary compound (3-number) below. Specifically, for example, Exemplified Compound 15 is hereinafter described as “exemplified compound (3-15)”.

In addition, the symbol in the said exemplary compound shows the following meaning.
Ph: phenyl group

The specific electron transport materials may be used alone or in combination of two or more. Moreover, you may use together electron transport materials other than a specific electron transport material as needed in the range which does not inhibit the objective of this embodiment.
In addition, as content in the case of containing electron transport materials other than a specific electron transport material, it is desirable that it is the range of 10 mass% or less with respect to the whole electron transport material.

  As other electron transport materials, for example, quinone compounds such as p-benzoquinone, chloranil, bromanyl, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, xanthone compounds And electron transporting compounds such as benzophenone compounds, cyanovinyl compounds and ethylene compounds. Although these other electron transport materials may be used individually by 1 type or in mixture of 2 or more types, it is not limited to these.

The content of the electron transport material relative to the total solid content of the photosensitive layer is preferably 5% by mass to 30% by mass, and more preferably 10% by mass to 20% by mass.
By the content of the electron transport material relative to the total solid content of the photosensitive member being in the above range, the electrical characteristics of the photosensitive member become better as compared with the case where the content is smaller than the above range, and compared with the case where the content is larger than the above range And color points (dot-like image defects) are less likely to occur.
In addition, content of this electron transport material is the content of those electron transport materials whole, when 2 or more types of electron transport materials are used together.

The mass ratio (hole transport material / electron transport material) of the hole transport material to the electron transport material is preferably 50/50 to 90/10, more preferably 60/40 to 80/20.
In addition, this ratio is a ratio in the sum, when using another charge transport material together.

-Other additives-
The single-layer type photosensitive layer may contain other known additives such as surfactants, antioxidants, light stabilizers and heat stabilizers. When the single-layer type photosensitive layer is a surface layer, it may contain fluorine resin particles, silicone oil and the like.

-Formation of single layer type photosensitive layer-
The single-layer type photosensitive layer is formed using a coating solution for forming a photosensitive layer in which the above components are added to a solvent.
As the solvent, aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, halogenated aliphatic hydrocarbons such as methylene chloride, chloroform and ethylene chloride, tetrahydrofuran, ethyl ether And organic solvents such as cyclic or linear ethers. These solvents are used singly or in combination of two or more.

  As a method of dispersing particles (for example, charge generating material) in a coating solution for forming a photosensitive layer, media dispersion machines such as a ball mill, vibration ball mill, attritor, sand mill, horizontal sand mill, stirring, ultrasonic dispersion machine, roll mill, Medialess dispersers such as high pressure homogenizers are used. The high-pressure homogenizer includes a collision method in which the dispersion is dispersed in liquid-liquid collision or liquid-wall collision in a high pressure state to disperse it, a penetration method in which a fine flow path is penetrated and dispersed in a high pressure state.

  As a method of applying the coating liquid for photosensitive layer formation on the undercoat layer, dip coating method, push-up coating method, wire bar coating method, spray coating method, blade coating method, knife coating method, curtain coating method, etc. may be mentioned. .

  The film thickness of the single layer type photosensitive layer is desirably set in the range of 5 to 60 μm, more desirably 5 to 50 μm, and further desirably 10 to 40 μm.

(Other layers)
As mentioned above, other layers may be provided as needed. As another layer, the protective layer provided as an outermost surface layer on a photosensitive layer is mentioned, for example. The protective layer is provided, for example, for the purpose of preventing chemical change of the photosensitive layer at the time of charging, or further improving the mechanical strength of the photosensitive layer. Therefore, as the protective layer, a layer formed of a cured film (crosslinked film) may be applied. Examples of these layers include the layers shown in the following 1) or 2).

1) A layer composed of a cured film of a composition containing a reactive group-containing charge transporting material having a reactive group and a charge transporting skeleton in the same molecule (that is, a polymer or a crosslink of the reactive group-containing charge transporting material Layer containing the body)
2) A layer composed of a cured film of a composition including a non-reactive charge transport material and a reactive group-containing non-charge transport material having no charge transport skeleton and having a reactive group (that is, A layer comprising a non-reactive charge transport material and a polymer or cross-linked product of the reactive group-containing non-charge transport material

As a reactive group of the reactive group-containing charge transporting material, a chain polymerizable group, an epoxy group, -OH, -OR (wherein R represents an alkyl group), -NH ₂ , -SH, -COOH, -SiR ^{Q 1} _3- ^Q _n (OR ^{Q 2} ) ^Q _n [wherein, R ^Q1 represents a hydrogen atom, an alkyl group, or a substituted or unsubstituted aryl group, and R ^Q2 represents a hydrogen atom, an alkyl group, or a trialkylsilyl group. Qn represents an integer of 1 to 3] and the like.

  The chain polymerizable group is not particularly limited as long as it is a radically polymerizable functional group, and is, for example, a functional group having a group containing at least a carbon double bond. Specific examples thereof include a group containing at least one selected from a vinyl group, a vinyl ether group, a vinyl thioether group, a styryl group, an acryloyl group, a methacryloyl group, and derivatives thereof. Among them, a chain polymerizable group is preferably a group containing at least one selected from a vinyl group, a styryl group, an acryloyl group, a methacryloyl group, and derivatives thereof because of excellent reactivity. .

  The charge transporting skeleton of the reactive group-containing charge transporting material is not particularly limited as long as it has a known structure in an electrophotographic photosensitive member, and, for example, triarylamine compounds, benzidine compounds, hydrazone compounds, etc. And a structure derived from the nitrogen-containing hole-transporting compound of the above, which is conjugated to a nitrogen atom. Among these, a triarylamine skeleton is preferable.

  The reactive group-containing charge transporting material having the reactive group and the charge transporting skeleton, the nonreactive charge transporting material, and the reactive group-containing non-charge transporting material may be selected from known materials.

  The protective layer may further contain known additives.

  The formation of the protective layer is not particularly limited, and a known formation method is used. For example, a coating film of a coating solution for forming a protective layer obtained by adding the above components to a solvent is formed, and the coating film is dried. It is carried out by curing treatment such as heating if necessary.

As a solvent for preparing a coating solution for forming a protective layer, aromatic solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; tetrahydrofuran And ether solvents such as dioxane; cellosolv solvents such as ethylene glycol monomethyl ether; alcohol solvents such as isopropyl alcohol and butanol. These solvents are used alone or in combination of two or more.
The coating solution for forming a protective layer may be a non-solvent coating solution.

  As a method of applying a coating solution for forming a protective layer on a photosensitive layer (for example, charge transport layer), dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, curtain coating The usual methods such as the law can be mentioned.

  The film thickness of the protective layer is, for example, preferably in the range of 1 μm to 20 μm, more preferably 2 μm to 10 μm.

[Image forming apparatus (and process cartridge)]
The image forming apparatus according to the present embodiment includes an electrophotographic photosensitive member, a charging unit that charges the surface of the electrophotographic photosensitive member, and an electrostatic latent image forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member. Developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner, thereby forming a toner image, and transfer means for transferring the toner image to the surface of the recording medium, Equipped with Then, the electrophotographic photosensitive member according to the present embodiment is applied as the electrophotographic photosensitive member.

  The image forming apparatus according to the present embodiment includes a fixing unit that fixes a toner image transferred to the surface of a recording medium; a direct transfer that directly transfers a toner image formed on the surface of an electrophotographic photosensitive member to a recording medium Type of device; primary transfer of the toner image formed on the surface of the electrophotographic photosensitive member to the surface of the intermediate transfer member, and secondary transfer of the toner image transferred onto the surface of the intermediate transfer member to the surface of the recording medium A device of the type; a device provided with a cleaning means for cleaning the surface of the electrophotographic photosensitive member before charging after transfer of the toner image; after the transfer of the toner image, the surface of the image carrier is irradiated with static elimination light before charging A known image forming apparatus such as a device including a discharging unit for discharging electricity; a device including an electrophotographic photosensitive member heating member for raising the temperature of the electrophotographic photosensitive member and reducing the relative temperature is applied.

  In the case of an intermediate transfer type apparatus, for example, an intermediate transfer member to which a toner image is transferred on the surface, and a primary transfer on which the toner image formed on the surface of the image carrier is primarily transferred to the surface of the intermediate transfer member. A configuration is applied that includes a unit and a secondary transfer unit that secondarily transfers the toner image transferred to the surface of the intermediate transfer member to the surface of the recording medium.

  The image forming apparatus according to the present embodiment may be either a dry developing type image forming apparatus or a wet developing type (developing type using a liquid developer) image forming apparatus.

  In the image forming apparatus according to the present embodiment, for example, the part including the electrophotographic photosensitive member may have a cartridge structure (process cartridge) which is detached from the image forming apparatus. As the process cartridge, for example, a process cartridge provided with the electrophotographic photosensitive member according to the present embodiment is suitably used. The process cartridge may include, in addition to the electrophotographic photosensitive member, at least one selected from the group consisting of a charging unit, an electrostatic latent image forming unit, a developing unit, and a transfer unit.

  Hereinafter, although an example of the image forming apparatus according to the present embodiment is shown, the present invention is not limited to this. The main parts shown in the figure will be described, and the description of the other parts will be omitted.

FIG. 2 is a schematic configuration view showing an example of the image forming apparatus according to the present embodiment.
The image forming apparatus 100 according to the present embodiment, as shown in FIG. 2, includes a process cartridge 300 including an electrophotographic photosensitive member 7, an exposure device 9 (an example of an electrostatic latent image forming unit), and a transfer device 40 (primary). A transfer device) and an intermediate transfer member 50 are provided. In the image forming apparatus 100, the exposure device 9 is disposed from the opening of the process cartridge 300 at a position where exposure to the electrophotographic photosensitive member 7 is possible, and the transfer device 40 is the electrophotographic photosensitive member via the intermediate transfer member 50. The intermediate transfer member 50 is disposed so as to be in contact with the electrophotographic photosensitive member 7. Although not shown, it also has a secondary transfer device for transferring the toner image transferred to the intermediate transfer member 50 to a recording medium (for example, a sheet). The intermediate transfer member 50, the transfer device 40 (primary transfer device), and the secondary transfer device (not shown) correspond to an example of the transfer unit.

  In the process cartridge 300 in FIG. 2, the electrophotographic photosensitive member 7, the charging device 8 (an example of the charging means), the developing device 11 (an example of the developing means), and the cleaning device 13 (an example of the cleaning means) In favor of The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is disposed in contact with the surface of the electrophotographic photosensitive member 7. The cleaning member may be a conductive or insulating fibrous member instead of the cleaning blade 131, and may be used alone or in combination with the cleaning blade 131.

  In FIG. 2, as an image forming apparatus, a fibrous member 132 (roll-like) for supplying the lubricant 14 to the surface of the electrophotographic photosensitive member 7 and a fibrous member 133 for assisting cleaning (flat brush-like) An example is shown, but these are arranged as needed.

  Hereinafter, each configuration of the image forming apparatus according to the present embodiment will be described.

-Charging device-
As the charging device 8, for example, a contact type charging device using a conductive or semiconductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube or the like is used. In addition, non-contact type roller chargers, scorotron chargers utilizing corona discharge, corotron chargers, etc., per se known chargers and the like are also used.

-Exposure apparatus-
Examples of the exposure device 9 include an optical system device that exposes the surface of the electrophotographic photosensitive member 7 with light such as semiconductor laser light, LED light, liquid crystal shutter light, etc. in a defined image. The wavelength of the light source is in the spectral sensitivity region of the electrophotographic photosensitive member. As the wavelength of the semiconductor laser, near infrared light having an oscillation wavelength around 780 nm is the mainstream. However, the wavelength is not limited to this, and a laser having an oscillation wavelength of 400 nm or more and 450 nm or less may be used as an oscillation wavelength laser of about 600 nm or a blue laser. In addition, a surface emitting laser light source of a type capable of outputting multiple beams is also effective for color image formation.

-Development device-
Examples of the developing device 11 include, for example, a general developing device which develops with a developer in contact or non-contact. The developing device 11 is not particularly limited as long as it has the above-described function, and is selected according to the purpose. For example, a known developing device or the like having a function of causing the one-component developer or the two-component developer to adhere to the electrophotographic photosensitive member 7 using a brush, a roller or the like can be mentioned. Among them, one using a developing roller holding a developer on the surface is preferable.

  The developer used in the developing device 11 may be a single component developer of toner alone, or may be a two component developer including toner and carrier. The developer may be magnetic or nonmagnetic. As these developers, known ones are applied.

-Cleaning device-
As the cleaning device 13, a cleaning blade type device provided with a cleaning blade 131 is used.
In addition to the cleaning blade method, a fur brush cleaning method or a development simultaneous cleaning method may be employed.

-Transfer device-
The transfer device 40 may be, for example, a contact type transfer charger using a belt, a roller, a film, a rubber blade or the like, a scorotron transfer charger using corona discharge, a corotron transfer charger, etc. It can be mentioned.

-Intermediate transfer body-
As the intermediate transfer member 50, a belt-like member (intermediate transfer belt) containing semiconductive conductive polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber and the like is used. The intermediate transfer member may be in the form of a drum other than the belt.

FIG. 3 is a schematic configuration view showing another example of the image forming apparatus according to the present embodiment.
An image forming apparatus 120 shown in FIG. 3 is a tandem multicolor image forming apparatus in which four process cartridges 300 are mounted. In the image forming apparatus 120, four process cartridges 300 are arranged in parallel on the intermediate transfer member 50, and one electrophotographic photosensitive member is used for one color. The image forming apparatus 120 has the same configuration as that of the image forming apparatus 100 except that the image forming apparatus 120 is a tandem system.

  The image forming apparatus 100 according to the present embodiment is not limited to the above configuration. For example, the cleaning device may be around the electrophotographic photosensitive member 7 and downstream of the transfer device 40 in the rotational direction of the electrophotographic photosensitive member 7. Alternatively, the first charge removing device may be provided on the upstream side of the electrophotographic photosensitive member in the rotational direction of the electrophotographic photosensitive member 13 so as to make the polarity of the remaining toner uniform and to be easily removed by the cleaning brush. The second charge removing device for removing the surface of the electrophotographic photosensitive member 7 may be provided on the downstream side of the rotating direction of the electrophotographic photosensitive member and further upstream of the charging device 8 in the rotating direction of the electrophotographic photosensitive member than the charging device 8. .

  Further, the image forming apparatus 100 according to the present embodiment is not limited to the above configuration, and may be a known configuration, for example, a direct transfer type image forming apparatus for directly transferring a toner image formed on the electrophotographic photosensitive member 7 to a recording medium. It may be adopted.

  Hereinafter, the present invention will be more specifically described based on examples and comparative examples, but the present invention is not limited to the following examples.

Example 1
-Formation of photosensitive layer-
1.5 parts by mass of a hydroxygallium phthalocyanine pigment shown in Table 1 below as a charge generating material, a polycarbonate resin having m and a viscosity average molecular weight in the above general formula (1) as a binding resin as shown in Table 1 below. 5 parts by mass, 13 parts by mass of an electron transporting material shown in the following Table 1 as an electron transporting material, 34 parts by mass of a hole transporting material shown in the following Table 1 as a hole transporting material, 250 parts by mass of tetrahydrofuran as a solvent The mixture was dispersed by a sand mill for 4 hours using glass beads having a diameter of 1 mmφ to obtain a coating solution for forming a photosensitive layer.

The obtained coating solution for photosensitive layer formation is coated on an aluminum substrate having a diameter of 30 mm, a length of 244.5 mm, and a thickness of 1 mm by dip coating, and dried and cured at 140 ° C. for 30 minutes. A 30 μm thick single-layered photosensitive layer was formed.
Through the above steps, an electrophotographic photosensitive member was produced.

Examples 2 to 17 and Comparative Examples 1 to 10
According to Tables 1 and 2, the m and viscosity average molecular weight of the binder resin used in the coating solution for forming a photosensitive layer, the type and amount of electron transport material, the type and amount of hole transport material, and the type of charge generating material An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the addition amount was changed.
In addition, "-" in Table 1 and Table 2 represents not adding.

<Evaluation>
The following evaluation was performed about each obtained electrophotographic photosensitive member. The results are shown in Tables 1 and 2.

-Photosensitive body sensitivity evaluation-
The sensitivity of the photosensitive member was evaluated as a half-exposure amount when charged to + 800V. Specifically, using an electrostatic copying paper testing apparatus (electrostatic analyzer EPA-8100, manufactured by Kawaguchi Electric Co., Ltd.), after being charged to +800 V under an environment of 20 ° C. and 40% RH, the light of a tungsten lamp is Using a monochromator, monochromatic light of 800 nm was adjusted to 1 μW / cm ² on the surface of the photosensitive member, and irradiation was performed. Then, the surface potential Vo (V) of the surface of the photosensitive member immediately after charging, and the half-exposure amount E1 / 2 (μJ / cm ² ) at which the surface potential becomes 1/2 × Vo (V) by light irradiation of the photosensitive member surface did.

Evaluation criteria are as follows.
A: The half-exposure dose was 0.15 μJ / cm ² or less.
B: The half-exposure dose was more than 0.15 μJ / cm ² and not more than 0.2 μJ / cm ² .
C: The half exposure dose exceeded 0.2 μJ / cm ² .

-Color point evaluation-
Color points are evaluated by printing 2000 50% halftone images at a charging voltage of +800 V in a high-temperature, high-humidity environment of 28 ° C and 85 RH% using a modified model of HL5340D made by Brother equipped with a photoconductor. The apparatus was stopped, and the number of color points generated on the paper when the blank paper was conveyed in the apparatus the next morning was counted and evaluated according to the following criteria.
A: Color point not generated.
B: 1 to 9 color points.
C: 10 or more color points.

-Productivity evaluation-
The productivity was evaluated by measuring the film thickness of the manufactured photosensitive member. The film thickness of the photosensitive member is 4 points in the circumferential direction (the circumferential direction base point is arbitrarily set, 4 points of 0 °, 90 °, 180 °, 270 °), and 24 points at 10 mm pitch from the upper end 10 mm in the axial direction. A total of 96 points were measured, and the average film thickness of 4 points at the top 10 mm position was taken as the top film thickness, and the average of 92 points in total from the top 20 mm to 240 mm positions was taken as the average film thickness of the photoreceptor. For the measurement, a film thickness measurement device (Permascope manufactured by Fisherscope Co., Ltd.) was used. The upper end refers to the end of the upper end during dip coating.
The difference between the average film thickness and the upper film thickness was evaluated according to the following criteria.
A: Difference between average film thickness and upper film thickness ≦ 1 μm
B: 1 μm <difference between average film thickness and upper film thickness ≦ 1.5 μm
C: 1.5 μm <difference between average film thickness and upper film thickness

The details of the abbreviations in Tables 1 and 2 are as follows.
-Charge generation material-
CGM1 (HOGaPC): hydroxygallium phthalocyanine (type V): Bragg angle (2θ ± 0.2 °) of X-ray diffraction spectrum using Cukα characteristic X-ray is at least 7.3 °, 16.0 °, 24. V-type hydroxygallium phthalocyanine pigment having a diffraction peak at 9 ° and 28.0 ° (maximum peak wavelength in spectral absorption spectrum in the wavelength range of 600 nm to 900 nm = 820 nm, average particle diameter = 0.12 μm, maximum Particle size = 0.2 μm, specific surface area = 60 m ² / g)

CGM2 (ClGaPC): chlorogallium phthalocyanine: Bragg angles (2θ ± 0.2 °) of at least 7.4 °, 16.6 °, 25.5 °, 28 in the X-ray diffraction spectrum using Cukα characteristic X-ray Chlorogallium phthalocyanine pigment having a diffraction peak at the position of 3. 3 ° (maximum peak wavelength in spectral absorption spectrum in the wavelength range of 600 nm to 900 nm = 780 nm, average particle size = 0.15 μm, maximum particle size = 0.2 μm, Specific surface area = 56 m ² / g)

CGM 3 (H ₂ PC): X-type metal-free phthalocyanine pigment (phthalocyanine in which two hydrogen atoms are coordinated to the center of the phthalocyanine skeleton)
CGM 4 (TiOPC): Y-type titanyl phthalocyanine pigment having a diffraction peak at a Bragg angle (2θ ± 0.2 °) of at least 9.6 ° and 27.3 °

-Hole transport material-
-HTM 1: Exemplified compound (2-1) of the hole transport material represented by the general formula (2)
· HTM2: N, N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1 '] biphenyl-4,4'-diamine (hole transport material HTM2 of the following structure)
HTM 3: 4- (2,2-diphenylethenyl) -N, N-bis (4-methylphenyl) benzeneamine (hole transport material HTM3 of the following structure)
・ HTM4: Hole transport material HTM4 of the following structure
・ HTM5: Hole transport material HTM5 of the following structure
-HTM 6: Exemplary compound (2-21) of the hole transport material represented by the general formula (2)

-Electron transport material-
-ETM 1: Exemplified compound (3-14) of the electron transporting material represented by the general formula (3)
-ETM 2: Exemplified compound (3-15) of the electron transport material represented by the general formula (3)
-ETM 3: Exemplified compound (3-2) of the electron transport material represented by the general formula (3)
・ ETM4: Electron transport material ETM4 of the following structure
ETM 5: exemplified compound (3-11) of the electron transporting material represented by the general formula (3)
ETM 6: Exemplary compound (3-17) of the electron transporting material represented by the general formula (3)

  From the above results, it is understood that the generation of the color point is suppressed in this example as compared with Comparative Examples 1 to 5 in which m is out of the above range as the binder resin.

DESCRIPTION OF SYMBOLS 1 subbing layer, 2 photosensitive layer, 3 electroconductive substrates, 7 electrophotographic photosensitive members, 8 charging devices, 9 exposure devices, 10 electrophotographic photosensitive members, 11 developing devices, 13 cleaning devices, 14 lubricants, 40 transfer devices, Reference Signs List 50 intermediate transfer body, 100 image forming apparatus, 120 image forming apparatus, 131 cleaning blade, 132 fibrous member, 133 fibrous member, 300 process cartridge

Claims (5)

A conductive substrate,
It is a single-layer type photosensitive layer provided on the said conductive substrate, Comprising: Binder resin which has a viscosity average molecular weight of 70,000 or more and 100,000 or less containing the structural unit represented by following General formula (1) And at least one charge generating material selected from a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment, a hole transporting material represented by the following general formula (2), and the following general formula (3) A photosensitive layer containing an electron transporting material,
An electrophotographic photosensitive member having

(In the general formula (1), m and n represent a copolymerization molar ratio, m is 15 or more and 25 or less, n is 75 or more and 85 or less, and m + n = 100.)

(In general formula (2), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom, or A lower alkyl group, a lower alkoxy group and a phenyl group which may have a substituent selected from a halogen atom, and p and q each independently represent 0 or 1)

(In general formula (3), R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, or .R ¹⁸ of an aralkyl group, an aralkyl group or 5 or more 10 or less branched alkyl group having a carbon.) The electrophotographic photosensitive member according to claim 1, wherein the charge generation material is a V-type hydroxygallium phthalocyanine pigment. The electrophotographic photosensitive member according to claim 1, wherein the hole transport material is a hole transport material in which p and q in the general formula (2) each represent 1. An electrophotographic photosensitive member according to any one of claims 1 to 3 ;
Process cartridge to be attached to and removed from the image forming apparatus. An electrophotographic photosensitive member according to any one of claims 1 to 3 ;
Charging means for charging the surface of the electrophotographic photosensitive member;
Electrostatic latent image forming means for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member charged;
Developing means for developing an electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image;
A transfer unit that transfers the toner image to the surface of a recording medium;
An image forming apparatus comprising: