JP2015169671A - Electrophotographic photoreceptor, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor with which a reduction in density of solid images can be suppressed with high sensitivity.SOLUTION: An electrophotographic photoreceptor 10 includes: a conductive substrate 4; an undercoat layer 1 that is provided on the conductive substrate and includes a metal alkoxy compound; and a single-layered photosensitive layer 2 that is provided on the undercoat layer and includes a binder resin, at least one charge generating material selected from a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment, a hole transport material, and an electron transport material.

Description

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

  In a conventional electrophotographic image forming apparatus, a toner image formed on the surface of an electrophotographic photosensitive member is transferred to a recording medium through processes of charging, exposure, development, and transfer.

It is known to use a charge transport material having an improved charge transport capability for the photosensitive layer of an electrophotographic photoreceptor used in such an electrophotographic image forming apparatus.
For example, an electron transport material having a specific molecular structure, improved electron transport properties, and increased sensitivity is known (see Patent Documents 1 and 2). A hole transport material having a specific molecular structure and improved hole transportability is also known (see Patent Document 3). In addition, various materials are known as charge transport materials (see Patent Document 4).

  Patent Document 5 discloses a conductive substrate and a single-layer type photosensitive layer provided on the conductive substrate, which includes a binder resin, a specific charge generation material, a hole transport material, and an electron transport material. An electrophotographic photosensitive member having a photosensitive layer configured to include the above is disclosed.

JP-A-6-123981 JP 2005-215679 A JP-A-8-295655 JP 2008-15208 A JP 2013-231867 A

  An object of the present invention is to provide an electrophotographic photosensitive member having high sensitivity and capable of suppressing a decrease in image density regardless of the environment even after toner deterioration.

The above problem is solved by the following means. That is,
The invention according to claim 1
A conductive substrate;
An undercoat layer provided on the conductive substrate and containing a metal alkoxy compound represented by the general formula (3);
A single-layer type photosensitive layer provided on the undercoat layer, comprising a binder resin, at least one charge generation material selected from a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment, and the following general formula ( A photosensitive layer comprising a hole transport material represented by 1) and an electron transport material represented by the following general formula (2);
An electrophotographic photosensitive member having:

(In General Formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ are each independently a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom, or A phenyl group which may have a substituent selected from a lower alkyl group, a lower alkoxy group and a halogen atom, and m and n each independently represent 0 or 1.

(In the general formula (2), R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, Or R ¹⁸ represents an alkyl group, an aryl group, or an aralkyl group.

(A) _p- M- (OR < ²¹ >) _q General formula (3)
(In general formula (3), A represents an acetylacetonate group, M represents a metal atom, R ²¹ represents an alkyl group having 1 to 8 carbon atoms, p represents an integer of 0 or more, and q Represents an integer of 1 or more, and p + q ≦ 4.)

The invention according to claim 2
The electrophotographic photosensitive member according to claim 1, wherein M in the general formula (3) is zirconium.

The invention according to claim 3
The electrophotographic photosensitive member according to claim 1 or 2,
A process cartridge that can be attached to and detached from an image forming apparatus.

The invention according to claim 4
The electrophotographic photosensitive member according to claim 1 or 2,
Charging means for charging the surface of the electrophotographic photosensitive member;
An electrostatic latent image forming means for 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 to form a toner image;
Transfer means for transferring the toner image to the surface of the recording medium;
An image forming apparatus comprising:

  According to the first and second aspects of the invention, compared to the case where the specific charge generation material, the hole transport material, and the photosensitive layer using the electron transport material and the specific undercoat layer are not combined, There is provided an electrophotographic photosensitive member having high sensitivity and capable of suppressing a decrease in image density regardless of the environment even after toner deterioration.

  According to the inventions according to claims 3 and 4, an electrophotographic photoreceptor in which the photosensitive layer using the specific charge generation material, the hole transport material, and the electron transport material is not combined with the specific undercoat layer. The present invention provides a process cartridge and an image forming apparatus that include an electrophotographic photosensitive member that has high sensitivity and can suppress a decrease in image density regardless of the environment even after toner deterioration.

1 is a schematic partial cross-sectional view showing an electrophotographic photosensitive member according to the present embodiment. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows the image forming apparatus which concerns on other this embodiment.

  Embodiments that are examples of the present invention will be described below.

[Electrophotographic photoreceptor]
The electrophotographic photoreceptor according to the exemplary embodiment (hereinafter sometimes referred to as “photoreceptor”) includes a conductive substrate, has an undercoat layer on the conductive substrate, and has a single layer type on the undercoat layer. A positively charged organic photoconductor (hereinafter sometimes referred to as a “single-layer photoconductor”).
The undercoat layer contains a metal alkoxy compound represented by the general formula (3).
The single-layer type photosensitive layer includes a binder resin, at least one charge generation material selected from a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment, and a hole transport material represented by the general formula (1). And an electron transport material represented by the general formula (2).
The single-layer type photosensitive layer is a photosensitive layer having hole transporting properties and electron transporting properties as well as charge generation ability.

  Here, conventionally, as the electrophotographic photoreceptor, a single-layer photoreceptor is desirable from the viewpoint of manufacturing cost and image quality stability. As described above, the single-layer type photoreceptor has a configuration in which a charge generation material, a hole transport material, and an electron transport material are contained in the single-layer type photosensitive layer. Therefore, it is difficult to obtain sensitivity as high as that of an organic photoreceptor having a laminated photosensitive layer. However, high sensitivity was realized by combining the specific charge generation material, hole transport material, and electron transport material into a single-layer type photosensitive layer.

  On the other hand, a single layer type photoreceptor using a combination of the specific charge generation material, hole transport material, and electron transport material is a single layer type photoreceptor using another material for a photosensitive layer or a multilayer type photoreceptor. Since a charge transport material having a low ionization potential is used in order to enhance the carrier transport capability as compared with the body and a charge generation material having a large amount of charge generation is used, it is considered that it is particularly susceptible to an electric field.

  In the case of using a photosensitive member that is easily affected by an electric field, for example, in the transfer process of transferring a toner image developed on the photosensitive member to a recording medium or the like, an electric field formed by a surface potential difference between the transfer roller and the photosensitive member itself. Depending on the case, charge injection or discharge may occur on the photosensitive member. When charge injection or discharge occurs on the photosensitive member, transfer failure is caused thereby, and as a result, there may be an image defect (blurring) due to a halftone or solid image density reduction.

  It is considered that the image defect due to the above-described decrease in image density is particularly likely to occur when an image is formed using deteriorated toner or when an image is formed in a high temperature and high humidity environment (for example, 28 ° C. and 85 RH%). It is done. Specifically, since the toner is difficult to transfer after the toner is deteriorated or in a high temperature and high humidity environment, a higher transfer voltage is required. It can be considered that the higher the transfer voltage is set, the more noticeable charge injection and discharge occur on the photoreceptor, and the more likely the image defects are generated. In addition, it is considered that the deterioration of the toner occurs, for example, when the toner is crushed when an image is formed by bringing the developing roller into contact with the photosensitive member in the contact development.

On the other hand, the photoreceptor of this embodiment has a configuration in which the specific charge generation material, the hole transport material, and the photosensitive layer using the electron transport material are combined with the specific undercoat layer. ing. Accordingly, the density of the image is suppressed with high sensitivity and without depending on the environment even after the deterioration of the toner (for example, in a high temperature and high humidity environment as described above).
The reason is not clear, but is presumed as follows.

In general, if the charge transport capacity of the undercoat layer is high, the effect of the undercoat layer on the photosensitivity of the photoconductor (photosensitivity during exposure) is small, but charge injection and discharge to the photoconductor in the transfer process It seems that it is easy to be influenced by. That is, when the undercoat layer has a high charge transport capability, the photosensitivity is less likely to be lower than when the undercoat layer is not provided, but transfer failure occurs when charge injection or discharge occurs on the photoreceptor. It is likely to be caused.
On the other hand, when the charge transport capability of the undercoat layer is low, it is less affected by charge injection or discharge to the photoconductor in the transfer process, but the effect of the undercoat layer on the photosensitivity of the photoconductor is considered to be large. . In other words, when an undercoat layer having a low charge transport capability is used, transfer defects are less likely to occur even if charge injection or discharge occurs on the photoreceptor, but the photosensitivity is lower than when no undercoat layer is provided. Seems to be remarkable.

  On the other hand, in this embodiment, the metal alkoxy compound represented by General formula (3) is contained in the undercoat layer. For this reason, protons are generated by the dissociation of adsorbed water at the defect sites formed by polycondensation and hydrolysis of the metal alkoxy compounds, and the charge transportability in the undercoat layer is maintained in an appropriate range by ionic conduction by the protons. It is thought to be drunk. As a result, it is presumed that transfer defects are less likely to occur even if charge injection or discharge occurs on the photoreceptor while suppressing the influence of the undercoat layer on the photosensitivity.

  As described above, in this embodiment, high sensitivity is achieved by combining the specific charge generation material, hole transport material, and photosensitive layer using the electron transport material with the specific undercoat layer. However, it is presumed that suppression of a decrease in image density due to transfer failure is also realized.

Hereinafter, the electrophotographic photoreceptor according to the exemplary 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 this embodiment.
The electrophotographic photoreceptor 10 shown in FIG. 1 includes, for example, a conductive substrate 4, and an undercoat layer 1, a single-layer type photosensitive layer 2, and a protective layer 3 are provided on the conductive substrate 4 in this order. Is configured.
In addition, the protective layer 3 is a layer provided as needed.

  Hereinafter, each layer of the electrophotographic photoreceptor according to the exemplary embodiment will be described in detail. Note that the reference numerals are omitted.

(Conductive substrate)
Examples of the conductive substrate include metal plates (eg, aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.), metal drums, metal belts, etc. Is mentioned. In addition, as the conductive substrate, for example, paper, resin film, belt, etc. coated, vapor-deposited or laminated with a conductive compound (for example, conductive polymer, indium oxide, etc.), metal (for example, aluminum, palladium, gold, etc.) or an alloy, etc. Also mentioned. Here, “conductive” means that the volume resistivity is less than 10 ¹³ Ωcm.

  When the electrophotographic photosensitive member is used in a laser printer, the surface of the conductive substrate has a center line average roughness Ra of 0.04 μm or more and 0.5 μm for the purpose of suppressing interference fringes generated when laser light is irradiated. The surface is preferably roughened below. When non-interfering light is used as a light source, roughening for preventing interference fringes is not particularly required, but it is suitable for extending the life because it suppresses generation of defects due to irregularities on the surface of the conductive substrate.

  As a roughening method, for example, wet honing performed by suspending an abrasive in water and spraying it on 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 roughening method, without roughening the surface of the conductive substrate, conductive or semiconductive powder is dispersed in the resin to form a layer on the surface of the conductive substrate. The method of roughening by the particle | grains disperse | distributed in a layer is also mentioned.

  In the roughening treatment by anodic oxidation, a metal (for example, aluminum) conductive substrate is used as an anode, and an oxide film is formed on the surface of the conductive substrate by anodizing in an electrolyte solution. 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 contaminated, and has a large resistance fluctuation due to the environment. Therefore, the pores of the oxide film are blocked by the volume expansion due to the hydration reaction in pressurized water vapor or boiling water (a metal salt such as nickel may be added) against the porous anodic oxide film, and more stable hydration oxidation It is preferable to perform a sealing treatment for changing to a product.

  The thickness of the anodized film is preferably, for example, 0.3 μm or more and 15 μm or less. When this film thickness is within the above range, the barrier property against implantation 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 acidic treatment liquid or boehmite treatment.
The treatment with the acidic treatment liquid is performed as follows, for example. First, an acidic treatment liquid containing phosphoric acid, chromic acid and hydrofluoric acid is prepared. The mixing ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment liquid is, for example, in the range of 10% by mass to 11% by mass of phosphoric acid, in the range of 3% by mass to 5% by mass of chromic acid, The concentration of these acids is preferably in the range of 13.5% by mass or more and 18% by mass or less. The treatment temperature is preferably 42 ° C. or higher and 48 ° C. or lower, for example. The film thickness is preferably from 0.3 μm to 15 μm.

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

(Undercoat layer)
The undercoat layer includes at least a metal alkoxy compound represented by the following general formula (3), and may include other components such as a silane compound and a binder resin as necessary.
(A) _p- M- (OR < ²¹ >) _q General formula (3)

In general formula (3), A shows an acetylacetonate group. M represents a metal atom. R ²¹ represents an alkyl group having 1 to 8 carbon atoms. p represents an integer of 0 or more, q represents an integer of 1 or more, and p + q ≦ 4.

-Metal alkoxy compound represented by the general formula (3)-
First, the metal alkoxy compound represented by the general formula (3) will be described. A metal alkoxy compound is a compound in which an alkoxy group and an acetylacetonate group are coordinated in the molecule.

Examples of the metal atom represented by M in the general formula (3) include lithium, magnesium, aluminum, calcium, titanium, iron, copper, gallium, yttrium, zirconium, indium, tin, antimony, barium, lanthanum, and hafnium. Among them, titanium, zirconium and aluminum are preferable from the viewpoint of residual potential, and zirconium is more preferable.
R ²¹ in the general formula (3) is an alkyl group having 1 to 8 carbon atoms, and may be linear or branched.
P in the general formula (3) is an integer of 0 or more, preferably 0 or more, 2 or less, more preferably 0 or 1, and particularly preferably 1. Q in the general formula (3) is an integer of 1 or more, and preferably 1 or more and 4 or less. In addition, as above-mentioned, it is preferable that it is p + q <= 4 and is p + q = 4.

Among the metal alkoxy compounds represented by the general formula (3), examples of compounds in which p is 1 or more include zirconium tributoxyacetylacetonate, dipropoxybis (acetylacetonate) titanium, titanium dipropoxyacetylacetonate. And diisopropoxybis (acetylacetonate) aluminum.
Among the metal alkoxy compounds represented by the general formula (3), examples of the compound where p is 0 include, for example, zirconium tetraethylate, zirconium tetra-n-propylate, zirconium tetraisopropylate, zirconium tetra-n-butyrate, Zirconium alkoxides such as zirconium tetrapropoxide; Titanium alkoxides such as titanium tetra-n-propyrate, titanium tetraisopropylate, titanium tetra-n-butyrate, tetra (2-ethylhexyl) titanate, titanium tetrapropoxide; aluminum ethylate, aluminum And aluminum alkoxides such as isopropylate, mono-sec-butoxyaluminum diisopropylate, and aluminum-sec-butyrate.

  Although content of the metal alkoxy compound represented by General formula (3) contained in an undercoat layer is not specifically limited, For example, the range of 10 mass% or more and 50 mass% or less is mentioned with respect to the whole undercoat layer. From the viewpoint of half-exposure amount and transfer efficiency in the toner transfer step, the range of 13% by mass to 40% by mass is preferable, and the range of 16% by mass to 35% by mass is more preferable.

-Other components-
Examples of other components include a silane compound and a binder resin as described above.

  Examples of the silane compound include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris-2-methoxyethoxysilane, vinyltriacetoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-methacryloxypropyl. Trimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3- (2-aminoethylamino) propyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, Silane caps such as 3-ureidopropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane Examples include pulling agents.

  Although the content of the silane compound contained in the undercoat layer is not particularly limited, for example, a range of 0% by mass to 40% by mass with respect to the entire undercoat layer may be mentioned. From the viewpoint of easy influence, a range of 2% by mass to 35% by mass is preferable, and a range of 5% by mass to 30% by mass is more preferable.

Examples of the binder resin used for the undercoat layer include acetal resins (eg, polyvinyl butyral), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, and unsaturated polyesters. 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; 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 include a charge transport resin having a charge transport group, a conductive resin (for example, polyaniline) and the like.

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

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 to suppress moire images. It should be done.
Resin particles or the like may be added to the undercoat layer for adjusting the surface roughness. Examples of the resin particles include silicone resin particles and cross-linked polymethyl methacrylate resin particles. Further, the surface of the undercoat layer may be polished for adjusting the surface roughness. Examples of the polishing method include buffing, sandblasting, wet honing, and grinding.

  There is no particular limitation on the formation of the undercoat layer, and a well-known formation method is used. For example, a coating film for forming an undercoat layer in which the above components are added to a solvent is formed, and the coating film is dried. And heating as necessary.

Solvents for preparing the coating solution for forming the undercoat layer include known organic solvents such as alcohol solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone solvents, ketone alcohol solvents, ether solvents. Examples include solvents and ester solvents.
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, Examples include ordinary organic solvents such as n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene.

  Examples of the method for applying the coating liquid for forming the undercoat layer onto the conductive substrate include, for example, a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method. The usual methods, such as these, are mentioned.

  The coating film is dried at a temperature in the range of, for example, 10 ° C. to 250 ° C., preferably in the range of 100 ° C. to 180 ° C., for example, in the range of 5 minutes to 5 hours, preferably in the range of 10 minutes to 2 hours, Perform by air drying or static drying.

  The thickness of the undercoat layer is, for example, from 0.01 μm to 10 μm, preferably from 0.01 μm to 5 μm, more preferably from 0.05 μm to 2 μm, particularly preferably from 0.2 μm to 2 μm. Is done.

(Middle layer)
Although illustration is omitted, an intermediate layer may be further provided between the undercoat layer and the photosensitive layer.
An intermediate | middle layer is a layer containing resin, for example. Examples of the resin used for the intermediate layer include an acetal resin (for example, polyvinyl butyral), 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 given.
The intermediate layer may be a layer containing an organometallic compound. Examples of the organometallic compound used for the intermediate layer include organometallic compounds containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon.
The compounds used for 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 organometallic compound containing a zirconium atom or a silicon atom.

The formation of the intermediate layer is not particularly limited, and a well-known formation method is used. For example, a coating film of an intermediate layer forming coating solution in which the above components are added to a solvent is formed, and the coating film is dried and necessary. It is performed by heating according to.
As the coating method for forming the intermediate layer, usual methods 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, and a curtain coating method are used.

  For example, the thickness of the intermediate layer is preferably set in a range of 0.1 μm to 3 μm. An intermediate layer may be used as the undercoat layer.

(Single layer type photosensitive layer)
The single-layer type photosensitive layer includes a binder resin, a charge generation material, a hole transport material, an electron transport material, and, if necessary, other additives.

-Binder resin-
The binder resin is not particularly limited. For example, polycarbonate resin, 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 copolymer, silicone resin, silicone alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin , Poly-N-vinylcarbazole, polysilane and the like. These binder resins may be used alone or in combination of two or more.
Among these binder resins, in particular, from the viewpoint of film formability of the photosensitive layer, for example, a polycarbonate resin having a viscosity average molecular weight of 30,000 to 80,000 is preferable.
The content of the binder resin with respect to the total solid content of the photosensitive layer is from 35% by mass to 60% by mass, and preferably from 20% by mass to 35% by mass.

-Charge generation material-
As the charge generation material, at least one selected from hydroxygallium phthalocyanine pigment and chlorogallium phthalocyanine pigment is applied.
As the charge generation material, these pigments may be used alone or in combination as required. The charge generating material is preferably a hydroxygallium phthalocyanine pigment from the viewpoint of increasing the sensitivity of the photoreceptor and suppressing point defects in the image.

The hydroxygallium phthalocyanine pigment is not particularly limited, but a V-type hydroxygallium phthalocyanine pigment is preferable.
In particular, as a hydroxygallium phthalocyanine pigment, for example, in a spectral absorption spectrum in a wavelength region 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 provide more excellent dispersibility. Desirable from a viewpoint. When used as a material for an electrophotographic photosensitive member, excellent dispersibility, sufficient sensitivity, chargeability, and dark decay characteristics are easily obtained.

The hydroxygallium phthalocyanine pigment having the maximum peak wavelength in the range of 810 nm to 839 nm is preferably in a specific range for the average particle size and in a specific range for the BET specific surface area. Specifically, the average particle size is desirably 0.20 μm or less, more desirably 0.01 μm or more and 0.15 μm or less, while the BET specific surface area is desirably 45 m ² / g or more. 50 m ² / g or more is more desirable, and 55 m ² / g or more and 120 m ² / g or less is particularly desirable. The average particle size is a volume average particle size (d50 average particle size) measured by a laser diffraction / scattering particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.). Moreover, it is the value measured by the nitrogen substitution method using the BET-type specific surface area measuring device (Shimadzu Corporation make: Flow soap II2300).
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, the pigment particles tend to be coarse or aggregates of the pigment particles tend to be formed. In addition, defects such as dispersibility, sensitivity, chargeability, and dark decay characteristics tend to easily occur, which may easily cause image quality defects.

  The maximum particle size (maximum primary particle size) of the hydroxygallium phthalocyanine pigment is desirably 1.2 μm or less, more desirably 1.0 μm or less, and more desirably 0.3 μm or less. When the maximum particle size exceeds the above range, black spots tend 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 due to exposure of the photoreceptor to a fluorescent lamp or the like, and The specific surface area value is desirably 45 m2 / 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 CuKα characteristic X-rays. It is desirable that it is a V type having a diffraction peak.

On the other hand, the chlorogallium phthalocyanine pigment is not particularly limited, but a Bragg angle (2θ ± 0.2 °) of 7.4 °, 16.6 °, 25.25 can be obtained as an electrophotographic photosensitive material. It is desirable to have diffraction peaks at 5 ° and 28.3 °.
The maximum peak wavelength, average particle diameter, maximum particle diameter, and specific surface area value of a suitable spectral absorption spectrum of the chlorogallium phthalocyanine pigment are the same as those of the hydroxygallium phthalocyanine pigment.

  The content of the charge generating material with respect 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, a hole transport material represented by the general formula (1) is applied.

In general formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ are each independently a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom, or a lower group. A phenyl group optionally having a substituent selected from an alkyl group, a lower alkoxy group and a halogen atom is shown. m and n. Each independently represents 0 or 1.

In the general formula (1), examples of the lower alkyl group represented by R ^{1 to} R ⁶ include linear or branched alkyl groups having 1 to 4 carbon atoms. Specifically, for example, Examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and an isobutyl group.
Of these, the lower alkyl group is preferably a methyl group or an ethyl group.

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

In general formula (1), examples of the halogen atom represented by R ^{1 to} R ⁶ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In the general formula (1), examples of the phenyl group represented by R ^{1 to} R ⁶ include an unsubstituted phenyl group; a phenyl group substituted with a lower alkyl group such as a p-tolyl group and a 2,4-dimethylphenyl group; and a lower alkoxy group-substituted phenyl group such as a p-methoxyphenyl group; a halogen atom-substituted phenyl group such as a p-chlorophenyl group; and the like.
Examples of the substituent that can be substituted on the phenyl group include a lower alkyl group, an alkoxy group, and a halogen atom represented by R ^{1 to} R ⁶ .

The hole transport material represented by the general formula (1) is preferably a hole transport material in which m and n are 1 from the viewpoints of increasing sensitivity and suppressing point defect of an image, and in particular, R ^{1 to} R ^6. Are each independently a hydrogen atom, a lower alkyl group, or an alkoxy group, and a hole transport material in which m and n are 1 is desirable.

  Hereinafter, exemplary compounds of the hole transport material represented by the general formula (1) will be shown, but not limited thereto. In addition, the following exemplary compound numbers are described as an exemplary compound (1-number) below. Specifically, for example, Exemplified Compound 15 is represented below as “Exemplified Compound (1-15)”.

In addition, the abbreviations in the above exemplary compounds have the following meanings.
4-Me: a methyl group substituted at the 4-position of the phenyl group, 3-Me: a methyl group substituted at the 3-position of the phenyl group, 4-Cl: a chlorine atom substituted at the 4-position of the phenyl group, 4 -MeO: methoxy group substituted at the 4-position of the phenyl group, 4-F: fluorine atom substituted at the 4-position of the phenyl group, 4-Pr: propyl group substituted at the 4-position of the phenyl group, 4-OPh : Phenoxy group substituted at 4-position of phenyl group

  The content of the hole transport material with respect 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, content of this hole transport material is content of those whole hole transport materials, when the hole transport material represented by General formula (1) and another hole transport material are used together. .

-Electron transport material-
As the electron transport material, an electron transport material represented by the general formula (2) is applied.

In the general formula (2), 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 an aralkyl group. R ¹⁸ represents an alkyl group, an aryl group, or an aralkyl group.

In the general formula (2), examples of the halogen atom represented by R ^{11 to} R ¹⁷ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In general formula (2), examples of the alkyl group represented by R ^{11 to} R ¹⁷ include linear or branched alkyl groups having 1 to 4 carbon atoms (preferably 1 to 3 carbon atoms), Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and an isobutyl group.

In the general formula (2), examples of the alkoxy group represented by R ^{11 to} R ¹⁷ include an alkoxy group having 1 to 4 carbon atoms (preferably 1 to 3 carbon atoms), specifically, a methoxy group, An ethoxy group, a propoxy group, a butoxy group, etc. are mentioned.

In the general formula (2), examples of the aryl group represented by R ^{11 to} R ¹⁷ include a phenyl group and a tolyl group.
In the general formula (2), examples of the aralkyl group represented by R ^{11 to} R ¹⁷ include a benzyl group.
Among these, a phenyl group is desirable.

In the general formula (2), examples of the alkyl group represented by R ¹⁸ include a linear alkyl group having 5 to 10 carbon atoms and a branched alkyl group having 5 to 10 carbon atoms.
Examples of the linear alkyl group having 5 to 10 carbon atoms include, for example, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, and an n-heptyl group. , N-octyl group, n-nonyl group, n-decyl group and the like.
Examples of the branched alkyl group having 5 to 10 carbon atoms include 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, Examples include isooctyl group, sec-octyl group, tert-octyl group, isononyl group, sec-nonyl group, tert-nonyl group, isodecyl group, sec-decyl group, tert-decyl group and the like.

In the general formula (2), examples of the aryl group represented by R ¹⁸ include a phenyl group, a methylphenyl group, and a dimethylphenyl group.

In General Formula (2), examples of the aralkyl group represented by R ¹⁸ include a group represented by —R ¹⁹ —Ar. However, R ¹⁹ represents an alkylene group, and Ar represents an aryl group.
Examples of the alkylene group represented by R ¹⁹ include a linear or branched alkylene group having 1 to 8 carbon atoms, and include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, and an isobutylene group. , 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.

Specific examples of the aralkyl group represented by R ¹⁸ in the general formula (2) include a benzyl group, a methylbenzyl group, a dimethylbenzyl group, a phenylethyl group, a methylphenylethyl group, a phenylpropyl group, and a phenylbutyl group. Can be mentioned.

As an electron transport material represented by the general formula (2), R ¹⁸ is a branched alkyl group having 5 to 10 carbon atoms, an aryl group, or an aralkyl group from the viewpoint of increasing sensitivity and suppressing a decrease in image density. In particular, R ^{11 to} R ¹⁷ each independently represents a hydrogen atom, a halogen atom, or an alkyl group, and R ¹⁸ is a branched alkyl group having 5 to 10 carbon atoms. , An electron transport material exhibiting an aryl group or an aralkyl group is preferable.

  Hereinafter, although the exemplary compound of the electron transport material represented by General formula (2) is shown, it is not necessarily limited to this. In addition, the following exemplary compound numbers are described as an exemplary compound (2-number) below. Specifically, for example, Exemplified Compound 15 is represented below as “Exemplified Compound (2-15)”.

In addition, the abbreviations in the above exemplary compounds have the following meanings.
· Ph: phenyl or phenylene group · _p-C 2 _{H 5:} substituted ethyl group in the para position

  The content of the electron transport material with respect to the total solid content of the photosensitive layer is preferably 7% by mass or more and 22% by mass or less, and more preferably 10% by mass or more and 16% by mass or less. In addition, content of this electron transport material is content of the whole electron transport material, when the electron transport material represented by General formula (2) and another electron transport material are used together.

-Other charge transport materials-
In addition to the specific hole transport material and electron transport material, other charge transport materials (other hole transport materials and other electron transport materials) may be used in combination as long as the function is not impaired. However, the other charge transport material is preferably used in an amount of 10% by mass or less based on the whole hole transport material and electron transport material.

  Other charge transport materials include, for example, quinone compounds such as p-benzoquinone, chloranil, bromanyl, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, and xanthone compounds. Electron transporting compounds such as benzophenone compounds, cyanovinyl compounds, ethylene compounds; triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazones And hole transporting compounds such as a series compound. These other charge transport materials may be used alone or in combination of two or more, but are not limited thereto.

  Other charge transport materials are preferably a triarylamine derivative represented by the following structural formula (B-1) and a benzidine derivative represented by the following structural formula (B-2) from the viewpoint of charge mobility.

In Structural 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 ), wherein R ^{B3 to} R ^B7 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. The substituent is a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a substituted amino group substituted with an alkyl group having 1 to 3 carbon atoms.

(In Structural Formula (B-2), R ^B8 and R ^{B8 ′} may be the same or different, and each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or 1 to 5 carbon atoms. R ^B9 , R ^{B9 ′} , R ^B10 and R ^{B10 ′} may be the same or different and each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or 1 carbon atom. Or more, an alkoxy group having 5 or less, an amino group substituted with an alkyl group having 1 to 2 carbon atoms, a substituted or unsubstituted aryl group, -C (R ^B11 ) = C (R ^B12 ) (R ^B13 ), ^{or- CH = CH-CH = C (} R B14) indicates ^{(R B15),} representing the ^{R B11} to ^{R B15} are each independently a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, .m 2, m13, n12 and n13 represents 2 the following integers each independently 0 or greater.)

Here, among the triarylamine derivative represented by the structural formula (B-1) and the benzidine derivative represented by the structural formula (B-2), in particular, “—C ₆ H ₄ —CH═CH—CH═C Triarylamine derivatives having “(R ^B6 ) (R ^B7 )” and benzidine derivatives having “—CH═CH— ^CH═C (R ^B14 ) (R ^B15 )” are desirable.

-Ratio of hole transport material and electron transport material-
The ratio of the hole transport material to the electron transport material is preferably 50/50 or more and 90/10 or less, more preferably 60/40 or more and 80/20 or less in terms of mass ratio (hole transport material / electron transport material). is there.
In addition, this ratio is a ratio in total when other charge transport materials are used in combination.

-Other additives-
The single-layer type photosensitive layer may contain other known additives such as an antioxidant, a light stabilizer, and a heat stabilizer. Further, when the single-layer type photosensitive layer is a surface layer, it may contain fluororesin particles, silicone oil and the like.

-Formation of single-layer type photosensitive layer-
The single-layer type photosensitive layer is formed using a photosensitive layer forming coating solution in which the above components are added to a solvent.
Solvents include 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 and ethyl ether. And usual organic solvents such as cyclic or straight chain ethers. These solvents are used alone or in combination of two or more.

  As a method for dispersing particles (for example, charge generation material) in the coating solution for forming a photosensitive layer, a media disperser such as a ball mill, a vibrating ball mill, an attritor, a sand mill, a horizontal sand mill, an agitator, an ultrasonic disperser, a roll mill, Medialess dispersers such as high-pressure homogenizers are used. Examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high-pressure state, and a penetration method in which a fine flow path is dispersed in a high-pressure state.

  Examples of the method for applying the photosensitive layer forming coating solution onto the undercoat layer include dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, and curtain coating. .

  The film thickness of the single-layer type photosensitive layer is preferably set in the range of 5 μm to 60 μm, more preferably 10 μm to 50 μm.

(Protective layer)
The protective layer is provided on the photosensitive layer as necessary. The protective layer is provided, for example, for the purpose of preventing chemical change of the photosensitive layer during charging or further improving the mechanical strength of the photosensitive layer.
Therefore, it is preferable to apply a layer composed of a cured film (crosslinked film) as the protective layer. Examples of these layers include the layers shown in 1) or 2) below.

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

The reactive group of the reactive group-containing charge transport material includes a chain polymerizable group, an epoxy group, —OH, —OR [wherein R represents an alkyl group], —NH ₂ , —SH, —COOH, —SiR. ^Q1 _3-Qn (OR ^Q2 ) _Qn [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, and other well-known reactive groups.

  The chain polymerizable group is not particularly limited as long as it is a functional group capable of radical polymerization. For example, it is a functional group having a group containing at least a carbon double bond. Specific examples include groups containing at least one selected from a vinyl group, vinyl ether group, vinyl thioether group, styryl group, acryloyl group, methacryloyl group, and derivatives thereof. Among them, the 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 its excellent reactivity. .

  The charge transporting skeleton of the reactive group-containing charge transporting material is not particularly limited as long as it is a known structure in an electrophotographic photoreceptor, and examples thereof include triarylamine compounds, benzidine compounds, hydrazone compounds, and the like. And a structure conjugated from a nitrogen-containing hole transporting compound and conjugated with a nitrogen atom. Among these, a triarylamine skeleton is preferable.

  The reactive group-containing charge transport material having a reactive group and a charge transport skeleton, a non-reactive charge transport material, and a reactive group-containing non-charge transport material may be selected from well-known materials.

  In addition, the protective layer may 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 liquid for forming a protective layer in which the above components are added to a solvent is formed, and the coating film is dried. It is performed by performing a curing process such as heating as necessary.

Solvents for preparing the coating solution for forming the protective layer include 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 protective layer forming coating solution may be a solventless coating solution.

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

  The thickness of the protective layer is, for example, preferably set 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 formation that forms an electrostatic latent image on the surface of the charged electrophotographic photosensitive member. Means, developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image, and transfer means for transferring the toner image to the surface of the recording medium; Is provided. 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 an apparatus having fixing means for fixing a toner image transferred to the surface of a recording medium; direct transfer for directly transferring the toner image formed on the surface of the electrophotographic photosensitive member to the recording medium Type apparatus; intermediate transfer in which the toner image formed on the surface of the electrophotographic photosensitive member is primarily transferred onto the surface of the intermediate transfer member, and the toner image transferred onto the surface of the intermediate transfer member is secondarily transferred onto the surface of the recording medium. Type apparatus; apparatus provided with cleaning means for cleaning the surface of the electrophotographic photosensitive member after the toner image is transferred and before charging; after the toner image is transferred, the surface of the image carrier is irradiated with a charge-removing light before charging. A known image forming apparatus, such as an apparatus provided with a static elimination means for removing electricity; an apparatus provided with an electrophotographic photosensitive member heating member for increasing the temperature of the electrophotographic photosensitive member and reducing the relative temperature is applied.

  In the case of an intermediate transfer type apparatus, the transfer means includes, for example, an intermediate transfer body on which a toner image is transferred onto the surface, and a primary transfer that primarily transfers the toner image formed on the surface of the image holding body onto the surface of the intermediate transfer body. And a secondary transfer unit that secondarily transfers the toner image transferred onto the surface of the intermediate transfer body onto 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).

  Note that in the image forming apparatus according to the present embodiment, for example, the portion including the electrophotographic photosensitive member may have a cartridge structure (process cartridge) that is detachable from the image forming apparatus. As the process cartridge, for example, a process cartridge including the electrophotographic photosensitive member according to this embodiment is preferably used. In addition to the electrophotographic photosensitive member, the process cartridge may include 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, an example of the image forming apparatus according to the present embodiment will be described, but the present invention is not limited thereto. 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 diagram illustrating an example of an image forming apparatus according to the present embodiment.
As shown in FIG. 2, the image forming apparatus 100 according to the present embodiment 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. Transfer device) and an intermediate transfer member 50. In the image forming apparatus 100, the exposure device 9 is disposed at a position where the electrophotographic photosensitive member 7 can be exposed from the opening of the process cartridge 300, and the transfer device 40 is interposed between the electrophotographic photosensitive member via the intermediate transfer member 50. 7, and a part of the intermediate transfer member 50 is disposed in contact with the electrophotographic photosensitive member 7. Although not shown, it also has a secondary transfer device that transfers the toner image transferred to the intermediate transfer member 50 to a recording medium (for example, paper). The intermediate transfer member 50, the transfer device 40 (primary transfer device), and the secondary transfer device (not shown) correspond to an example of a transfer unit.

  A process cartridge 300 in FIG. 2 includes an electrophotographic photosensitive member 7, a charging device 8 (an example of a charging unit), a developing device 11 (an example of a developing unit), and a cleaning device 13 (an example of a cleaning unit) in a housing. I support it. The cleaning device 13 includes a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is disposed so as to contact 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 shape) for supplying the lubricant 14 to the surface of the electrophotographic photosensitive member 7 and a fibrous member 133 (flat brush shape) for assisting in cleaning are shown. Examples are provided, but these are arranged as necessary.

  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 charger 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. Further, a non-contact type roller charger, a known charger such as a scorotron charger using a corona discharge or a corotron charger may be used.

-Exposure device-
Examples of the exposure device 9 include optical system devices that expose the surface of the electrophotographic photoreceptor 7 with light such as semiconductor laser light, LED light, and liquid crystal shutter light in a predetermined image-like manner. The wavelength of the light source is set within the spectral sensitivity region of the electrophotographic photosensitive member. As the wavelength of the semiconductor laser, near infrared having an oscillation wavelength near 780 nm is the mainstream. However, the present invention is not limited to this wavelength, and an oscillation wavelength laser in the 600 nm range or a laser having an oscillation wavelength of 400 nm to 450 nm as a blue laser may be used. In addition, a surface-emitting type laser light source that can output a multi-beam is also effective for color image formation.

-Development device-
Examples of the developing device 11 include a general developing device that performs development by bringing a developer into contact or non-contact with the developer. The developing device 11 is not particularly limited as long as it has the functions described above, and is selected according to the purpose. For example, a known developing device having a function of attaching a one-component developer or a two-component developer to the electrophotographic photosensitive member 7 using a brush, a roller, or the like can be used. Among these, those using a developing roller holding the developer on the surface are preferable.

  The developer used in the developing device 11 may be a one-component developer including a toner alone or a two-component developer including a toner and a carrier. Further, the developer may be magnetic or non-magnetic. A well-known thing is applied for these developers.

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

-Transfer device-
As the transfer device 40, for example, a contact transfer charger using a belt, a roller, a film, a rubber blade, etc., or a known transfer charger such as a scorotron transfer charger using a corona discharge or a corotron transfer charger. Can be mentioned.

-Intermediate transfer member-
As the intermediate transfer member 50, a belt-like member (intermediate transfer belt) containing polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber or the like having semiconductivity is used. Further, as the form of the intermediate transfer member, a drum-like member may be used in addition to the belt-like member.

FIG. 3 is a schematic configuration diagram illustrating 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 equipped with four process cartridges 300. 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 it is a tandem system.

  Note that the image forming apparatus 100 according to the present embodiment is not limited to the above configuration, and is, for example, a cleaning device around the electrophotographic photosensitive member 7 and downstream of the transfer device 40 in the rotation direction of the electrophotographic photosensitive member 7. The first toner neutralizing device may be provided on the upstream side of the rotation direction of the electrophotographic photosensitive member with respect to 13 so that the polarity of the remaining toner is aligned and easily removed with a cleaning brush. Alternatively, a configuration may be adopted in which a second static elimination device for neutralizing the surface of the electrophotographic photosensitive member 7 is provided on the downstream side in the rotation direction of the electrophotographic photosensitive member and on the upstream side in the rotational direction of the electrophotographic photosensitive member relative to the charging device 8. .

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

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

<Example 1>
-Formation of undercoat layer-
A zirconium compound (zirconium tributoxy monoacetylacetonate, product name: ORGATIX) was added to a solution obtained by dissolving 40 parts by mass of polyvinyl butyral resin (ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.) in 100 parts by mass of n-butanol. ZC540 (manufactured by Matsumoto Fine Chemical Co., Ltd.) 55 parts by mass and silane compound (3-aminopropyltrimethoxysilane, product name: A1110, manufactured by Momentive Performance Materials) 5 parts by mass are added and mixed, and the undercoat layer is stirred. A forming coating solution was obtained.

  The obtained coating solution was applied on an aluminum substrate having a diameter of 30 mm and a length of 245 mm by a dip coating method, followed by heat drying at 150 ° C. for 10 minutes to form an undercoat layer having a thickness of 1 μm.

-Formation of photosensitive layer-
Bragg angles (2θ ± 0.2 °) of X-ray diffraction spectrum using Cukα characteristic X-ray as a charge generating material are at least 7.3 °, 16.0 °, 24.9 °, 28.0 °. 2 parts by mass of a V-type hydroxygallium phthalocyanine pigment (CGM1) having a diffraction peak, 48 parts by mass of a bisphenol Z polycarbonate resin (viscosity average molecular weight: 50,000, resin 1) as a binder resin, and the electron transport materials shown in Table 1 A mixture of 12 parts by mass, 38 parts by mass of the hole transport material shown in Table 1, and 250 parts by mass of tetrahydrofuran as a solvent was dispersed for 4 hours in a sand mill using glass beads having a diameter of 1 mmφ to form a photosensitive layer. A coating solution was obtained.

The obtained coating solution for forming a photosensitive layer is applied on the undercoat layer formed on the aluminum substrate by a dip coating method, dried and cured at 140 ° C. for 30 minutes, and a single layer having a thickness of 30 μm. A mold photosensitive layer was formed.
Through the above steps, an electrophotographic photosensitive member was produced.

<Examples 2-20, Comparative Examples 1-12>
According to Tables 1 to 4, the type and amount of the metal alkoxy compound, silane compound, and binder resin used in the undercoat layer forming coating solution, and the charge generating material, electron transport material used in the photosensitive layer forming coating solution, and An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the kind and amount of the hole transport material were changed.

<Comparative Example 13, Comparative Example 15, Comparative Example 17, and Comparative Example 19>
-Formation of undercoat layer-
100 parts by mass of zinc oxide (average particle size 70 nm: manufactured by Teica: specific surface area value 15 m 2 / g) is stirred and mixed with 500 parts by mass of tetrahydrofuran, and 1.3 parts by mass of a silane coupling agent (KBM503: manufactured by Shin-Etsu Chemical Co., Ltd.) is added. Added and stirred for 2 hours. Tetrahydrofuran was then distilled off under reduced pressure and baked at 120 ° C. for 3 hours to obtain a silane coupling agent surface-treated zinc oxide.

The obtained silane coupling agent surface-treated zinc oxide (110 parts by mass) was mixed with 500 parts by mass of tetrahydrofuran, and a solution prepared by dissolving 0.6 parts by mass of alizarin in 50 parts by mass of tetrahydrofuran was added. Stir for 5 hours. Then, the zinc oxide to which alizarin was imparted by filtration under reduced pressure was filtered off, and further dried at 60 ° C. under reduced pressure to obtain alizarin imparted zinc oxide.
60 parts by mass of this alizarin-provided zinc oxide, 13.5 parts by mass of a curing agent (blocked isocyanate Sumijoule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) and 15 parts by mass of butyral resin (ESLEC BM-1, manufactured by Sekisui Chemical Co., Ltd.) 38 parts by mass of the solution dissolved in parts by mass and 25 parts by mass of methyl ethyl ketone were mixed, and dispersed for 2 hours with a sand mill using 1 mmφ glass beads to obtain a dispersion.
Dioctyltin dilaurate: 0.005 parts by mass and silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone): 40 parts by mass were added as catalysts to the resulting dispersion to obtain a coating liquid for forming an undercoat layer.

  The obtained coating solution is applied onto an aluminum substrate (conductive substrate) having a diameter of 30 mm and a length of 245 mm by a dip coating method, followed by heat drying at 170 ° C. for 40 minutes, and an undercoat layer having a thickness of 19 μm. ("UCL1" in Table 5).

-Formation of photosensitive layer-
A photosensitive layer is formed on the undercoat layer in the same manner as in Example 1 except that the charge generation material, the electron transport material, and the hole transport material described in Table 5 are used. Produced.

<Comparative Example 14, Comparative Example 16, Comparative Example 18, and Comparative Example 20>
-Formation of anodized film-
An aluminum substrate surface having a diameter of 30 mm and a length of 245 mm is mirror-polished, degreased and washed with water, then immersed in an electrolytic bath of 10 ° C. and 15 vol% sulfuric acid, and anodized for 30 minutes at an electrolytic voltage of 15 V Went. Further, after washing with water, sealing treatment was performed with a 7% by mass nickel acetate aqueous solution (50 ° C.). Thereafter, scrubbing with pure water was performed to form a 7 μm anodic oxide film (“UCL2” in Table 5).

-Formation of photosensitive layer-
A photosensitive layer was formed on the anodized film in the same manner as in Example 1 except that the charge generation material, the electron transport material, and the hole transport material described in Table 5 were used. Produced.

<Evaluation>
The electrophotographic photoreceptor obtained in each example was evaluated as follows. The results are shown in Tables 1-5.

-Evaluation of sensitivity of photoconductor-
The sensitivity of the photoconductor was evaluated as a half exposure amount when charged to + 800V. Specifically, using an electrostatic copying paper test apparatus (electrostatic analyzer EPA-8100, manufactured by Kawaguchi Electric Mfg. Co., Ltd.), after charging to +800 in an environment of 20 ° C. and 40% RH, the light of the tungsten lamp Was monochromatic light of 780 nm using a monochromator, adjusted to 1 μW / cm ² on the surface of the photoreceptor, and irradiated.
Then, the surface potential V ₀ (V) on the surface of the photoconductor immediately after charging, and the half exposure amount E1 / 2 (μJ / cm ² ) at which the surface potential becomes 1/2 × V _O (V) by light irradiation on the surface of the photoconductor. Was measured.

-Image quality evaluation of solid images-
The image quality evaluation of a solid image was performed by using HL2240DW manufactured by BROTHER as an image forming apparatus, and after forming 1500 images with an image density of 5% under an environment of a temperature of 32 ° C. and a humidity of 85%, three solid images were output. Sensory evaluation was performed by selecting the one having the largest solid image density unevenness (that is, blur due to partial density reduction) among the three sheets. The evaluation criteria are shown below.
Note that, in the image quality evaluation of solid images, the following evaluation criteria G2 or more are practically acceptable.

G1: The image quality is very good (no solid image density unevenness)
G2: Image quality is in an acceptable range (the occurrence of solid image density unevenness is slight and within an acceptable range)
G3: Image quality is poor (solid image density unevenness occurs)
G4: Image quality is very poor (solid image density unevenness is noticeable)

  From the above results, it can be seen that in this example, better results were obtained for both the sensitivity of the photoconductor and the image quality evaluation of the solid image than in the comparative example.

Hereinafter, details of abbreviations in Tables 1 to 5 will be described.
-Metal alkoxy compound of undercoat layer-
ZC540: Zirconium tributoxy monoacetylacetonate (Product name: Orgatics ZC540, manufactured by Matsumoto Fine Chemical Co., Ltd., component concentration: 45% by mass)
ZA45: Zirconium tetrapropoxide (Product name: Orgatics ZA45, manufactured by Matsumoto Fine Chemical Co., Ltd., component concentration: 75% by mass)
TC100: Titanium dipropoxyacetylacetonate (Product name: Orgatechs TC100, manufactured by Matsumoto Fine Chemical Co., component concentration: 75% by mass)
TA10: Titanium tetrapropoxide (Product name: Orgatics TA10, manufactured by Matsumoto Fine Chemical Co., component concentration: 99% by mass)

-Silane compound in the undercoat layer-
A1110: 3-aminopropyltrimethoxysilane (Product name: A1110, manufactured by Momentive Performance Materials)
A2120: N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane (Product name: A2120, manufactured by Momentive Performance Materials)

−Binder resin for undercoat layer−
-BM-S: Polyvinyl butyral resin (ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.)
-BM-1: Butyral resin (ESREC BM-1, manufactured by Sekisui Chemical Co., Ltd.)

-Undercoat layer or anodized film-
-UCL1: Undercoat layer using the alizarin-added zinc oxide-UCL2: The anodized film

-Charge generation material for photosensitive layer-
CGM1: HOGaPC (V type): Bragg angles (2θ ± 0.2 °) of X-ray diffraction spectrum using Cukα characteristic X-ray are at least 7.3 °, 16.0 °, 24.9 °, 28. V-type hydroxygallium phthalocyanine pigment having a diffraction peak at 0 ° (maximum peak wavelength in spectral absorption spectrum in wavelength range of 600 nm to 900 nm = 820 nm, average particle size = 0.12 μm, maximum particle size = 0. 2 μm, specific surface area value = 60 m ² / g)

-CGM2: ClGaPC: Cukα X-ray diffraction spectrum Bragg angles (2θ ± 0.2 °) using characteristic X-rays are at least 7.4 °, 16.6 °, 25.5 °, 28.3 ° Chlorogallium phthalocyanine pigment having a diffraction peak (maximum peak wavelength in spectral absorption spectrum in wavelength range of 600 nm to 900 nm = 780 nm, average particle diameter = 0.15 μm, maximum particle diameter = 0.2 μm, specific surface area value = 56 m ² / g)
CGM3: 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 °.
CGM4: H ₂ PC: Metal-free phthalocyanine pigment (phthalocyanine in which two hydrogen atoms are coordinated to the center of the phthalocyanine skeleton)

-Electron transport material for photosensitive layer-
ETM1: Exemplary compound (2-11) of an electron transport material represented by the general formula (2) [in the general formula (2), R ^{11 to} R ¹⁷ = H, R ¹⁸ = n-C ₄ H ₉ electrons Transport material]
ETM2: Example compound (2-12) of an electron transport material represented by the general formula (2) [in the general formula (2), R ^{11 to} R ¹⁷ = H, R ¹⁸ = n-C ₁₁ H ₂₃ electrons Transport material]
ETM3: Electron transport material having the following structure ETM4: Compound (2-14) as an example of an electron transport material represented by the general formula (2) [in the general formula (2), R ^{11 to} R ¹⁷ = H, R ¹⁸ = Electron transport material of —CH ₂ —CH (C ₂ H ₅ ) —C ₄ H ₉ ]
ETM5: Compound (2-15) of the electron transport material represented by the general formula (2) [in the general formula (2), R ^{11 to} R ¹⁷ = H, R ¹⁸ =-(CH ₂ ) ₂ -Ph Electron transport material]
ETM6: Exemplary compound (2-16) of an electron transport material represented by the general formula (2) [in the general formula (2), R ^{11 to} R ¹⁷ = H, R ¹⁸ =-(CH ₂ ) ₂ -Ph electron transport material -C ₂ H _5]

-Hole transport material for photosensitive layer-
-HTM1: Example compound (1-1) of the hole transport material represented by General formula (1)
-HTM2: Example compound (1-2) of the hole transport material represented by the general formula (1)
・ HTM3: Hole transport material with the following structure

-Binder resin for photosensitive layer-
Resin 1: Bisphenol Z polycarbonate resin (viscosity average molecular weight: 50,000)

DESCRIPTION OF SYMBOLS 1 Undercoat layer, 2 Photosensitive layer, 3 Protective layer, 4 Conductive substrate, 7 Electrophotographic photosensitive member, 8 Charging device, 9 Exposure device, 10 Electrophotographic photosensitive member, 11 Developing device, 13 Cleaning device, 14 Lubricant, 40 transfer device, 50 intermediate transfer member, 100 image forming device, 120 image forming device, 131 cleaning blade, 132 fibrous member, 133 fibrous member, 300 process cartridge

Claims (4)

A conductive substrate;
An undercoat layer provided on the conductive substrate and containing a metal alkoxy compound represented by the general formula (3);
A single-layer type photosensitive layer provided on the undercoat layer, comprising a binder resin, at least one charge generation material selected from a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment, and the following general formula ( A photosensitive layer comprising a hole transport material represented by 1) and an electron transport material represented by the following general formula (2);
An electrophotographic photosensitive member having:

(In General Formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ are each independently a hydrogen atom, a lower alkyl group, an alkoxy group, a phenoxy group, a halogen atom, or (A phenyl group optionally having a substituent selected from a lower alkyl group, a lower alkoxy group and a halogen atom. M and n each independently represents 0 or 1.)

(In the general formula (2), R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, Or R ¹⁸ represents an alkyl group, an aryl group, or an aralkyl group.

(In general formula (3), A represents an acetylacetonate group, M represents a metal atom, R ²¹ represents an alkyl group having 1 to 8 carbon atoms, p represents an integer of 0 or more, and q Represents an integer of 1 or more, and p + q ≦ 4.)   The electrophotographic photosensitive member according to claim 1, wherein M in the general formula (3) is zirconium. The electrophotographic photosensitive member according to claim 1 or 2,
A process cartridge that can be attached to and detached from an image forming apparatus. The electrophotographic photosensitive member according to claim 1 or 2,
Charging means for charging the surface of the electrophotographic photosensitive member;
An electrostatic latent image forming means for 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 to form a toner image;
Transfer means for transferring the toner image to the surface of the recording medium;
An image forming apparatus comprising: