JP2019056753A - Electrophotographic photoreceptor, method for manufacturing electrophotographic photoreceptor, process cartridge, and image forming apparatus - Google Patents

Abstract

To provide an electrophotographic photoreceptor that has improved thin-line reproducibility.SOLUTION: An electrophotographic photoreceptor comprises: a conductive substrate; and a single-layer photosensitive layer that is provided on the conductive substrate and contains a binder resin and charge generating material, where in the single-layer photosensitive layer, 10 or less aggregates of the charge generating material having a maximum diameter of 400 nm or more are present in an area of 5 μm×5 μm on a cross section of the single-layer photosensitive layer.SELECTED DRAWING: None

Description

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

  Patent Document 1 states that “on a conductive substrate, at least one charge generation material selected from a binder resin, a hydroxygallium phthalocyanine pigment, and a chlorogallium phthalocyanine pigment, a hole transport material represented by a specific general formula. And an electrophotographic photosensitive member having a single-layer type photosensitive layer containing an electron transport material represented by a specific general formula and having a coarse particle coefficient calculated by using absorbance at 1000 nm of 0.025 or less, A charging means for contacting the surface of the electrophotographic photosensitive member and charging the surface using only a DC voltage; and forming an electrostatic latent image on the charged surface of the 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, and forming the toner image on the surface of the recording medium. The image forming apparatus includes a transfer unit that copy, a. "Is disclosed.

  Patent Document 2 states that “in an electrophotographic photoreceptor having a photosensitive layer containing a charge generation material, a charge transport material, and a resin binder on a conductive substrate, the charge generation material is dispersed as particles, and the average particle size is 2 μm or less. An electrophotographic photoreceptor characterized by the above is disclosed.

JP2015-152865A Japanese Patent No. 2000-147811

  In an electrophotographic photoreceptor having a single-layer type photosensitive layer, unlike an electrophotographic photoreceptor having a function-separated type photosensitive layer in which a charge generation layer and a charge transport layer are separately provided, a charge generation material is applied to the entire photosensitive layer. Since they are dispersed, the aggregation of the charge generating material tends to affect the image quality. Specifically, for example, when a thin line image is formed using an electrophotographic photosensitive member having a single-layer type photosensitive layer, the line width becomes thick, thin, or fluctuates, and the reproducibility of the thin line is increased. It may not be obtained.

  An object of the present invention is to provide an electrophotographic photosensitive member having a single-layer type photosensitive layer provided on a conductive substrate and containing a binder resin and a charge generating material, in a cross section of the single-layer type photosensitive layer, 5 μm × 5 μm. It is an object of the present invention to provide an electrophotographic photosensitive member having improved reproducibility of fine lines as compared with a case where the aggregate of charge generating materials having a maximum diameter of 400 nm or more existing in the above region exceeds ten.

The above problem is solved by the following means. That is,
The invention according to claim 1
A conductive substrate;
A single-layer type photosensitive layer provided on the conductive substrate and containing a binder resin and a charge generation material, and having a maximum diameter existing in a region of 5 μm × 5 μm in a cross section of the single-layer type photosensitive layer A single-layer type photosensitive layer having 10 or less aggregates of the charge generation material of 400 nm or more;
An electrophotographic photosensitive member having

The invention according to claim 2
2. The electrophotographic photosensitive member according to claim 1, wherein the number of aggregates of the charge generation material having a maximum diameter of 600 nm or more present in a region of 5 μm × 5 μm in a cross section of the single-layer type photosensitive layer is 5 or less.

The invention according to claim 3
The electrophotographic photosensitive member according to claim 1, wherein the charge generation material contains at least one of a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment.
The invention according to claim 4
4. The electrophotographic photosensitive member according to claim 3, wherein the content of the charge generating material is 0.5% by mass or more and 10% by mass or less with respect to the entire single-layer type photosensitive layer.
The invention according to claim 5
5. The electrophotographic photosensitive member according to claim 4, wherein the content of the charge generating material is 1% by mass or more and 7% by mass or less with respect to the entire single-layer type photosensitive layer.

The invention according to claim 6
The electrophotographic photosensitive member according to claim 1, wherein the single-layer type photosensitive layer contains a hole transport material.
The invention according to claim 7 provides:
The electrophotographic photoreceptor according to claim 6, wherein the hole transport material is a hole transport material represented by the following general formula (1).

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.

The invention according to claim 8 provides:
The electrophotographic photosensitive member according to claim 1, wherein the single-layer type photosensitive layer contains an electron transport material.
The invention according to claim 9 is:
The electrophotographic photosensitive member according to claim 8, wherein the electron transport material is an electron transport material represented by the following general formula (2).

In 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 An aralkyl group is shown. R ¹⁸ represents an alkyl group, a group represented by —L ¹⁹ —O—R ²⁰ , an aryl group, or an aralkyl group. ^{However, L 19} represents an alkylene ^{group, R 20} represents an alkyl group.

The invention according to claim 10 is:
The electrophotographic photosensitive member according to any one of claims 1 to 9,
It is a process cartridge that can be attached to and detached from the image forming apparatus.
The invention according to claim 11 is:
The electrophotographic photosensitive member according to any one of claims 1 to 9,
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.

  According to the invention of claim 1, 6, 7, 8, or 9, in an electrophotographic photosensitive member having a single-layer type photosensitive layer provided on a conductive substrate and containing a binder resin and a charge generating material. An electrophotographic photoreceptor with improved reproducibility of fine lines compared to a case where the aggregate of charge generation materials having a maximum diameter of 400 nm or more existing in a 5 μm × 5 μm region in a cross section of a single-layer type photosensitive layer exceeds ten. Provided.

  According to the second aspect of the present invention, compared to a case where the aggregate of charge generating materials having a maximum diameter of 600 nm or more existing in a 5 μm × 5 μm region in the cross section of the single-layer type photosensitive layer exceeds five, the fine line is reproduced. An electrophotographic photoreceptor having improved properties is provided.

According to the invention of claim 3, in the electrophotographic photosensitive member in which the single-layer type photosensitive layer contains a charge generation material containing at least one of a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment, An electrophotographic photoreceptor with improved reproducibility of fine lines is provided as compared to the case where the aggregate of charge generating materials having a maximum diameter of 400 nm or more existing in a 5 μm × 5 μm region in the cross section exceeds 10.
According to the invention of claim 4, even if the content of the charge generating material is 0.5% by mass or more and 10% by mass or less with respect to the entire single layer type photosensitive layer, the cross section of the single layer type photosensitive layer An electrophotographic photoreceptor with improved reproducibility of fine lines is provided as compared with the case where the aggregate of charge generation materials having a maximum diameter of 400 nm or more present in a region of 5 μm × 5 μm exceeds 10.
According to the invention of claim 5, even if the content of the charge generating material is 1% by mass or more and 7% by mass or less with respect to the entire monolayer type photosensitive layer, the cross section of the single layer type photosensitive layer is 5 μm × An electrophotographic photosensitive member with improved reproducibility of fine lines is provided as compared with the case where the aggregate of charge generating materials having a maximum diameter of 400 nm or more existing in a 5 μm region exceeds 10.

  According to the invention of claim 10 or claim 11, in the electrophotographic photosensitive member having a single layer type photosensitive layer provided on the conductive substrate and containing the binder resin and the charge generation material, A process cartridge or image comprising an electrophotographic photosensitive member with improved reproducibility of fine lines compared to a case where the aggregate of charge generating materials having a maximum diameter of 400 nm or more existing in a 5 μm × 5 μm region in the cross section of the photosensitive layer exceeds ten. A forming apparatus is provided.

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 photosensitive member according to the present embodiment (hereinafter sometimes simply referred to as “photosensitive member” or “single-layer type photosensitive member”) includes a conductive substrate, and a single-layer type photosensitive layer on the conductive substrate. Have
The single-layer type photosensitive layer contains a binder resin and a charge generation material, and the charge generation material having a maximum diameter of 400 nm or more existing in a region of 5 μm × 5 μm in the cross section of the single-layer type photosensitive layer. There are 10 or less aggregates.
The single-layer type photosensitive layer is a photosensitive layer having hole transporting properties and electron transporting properties as well as charge generation ability.
Hereinafter, the “single layer type photosensitive layer” may be simply referred to as “photosensitive layer”. The “number of aggregates of the charge generation material having a maximum diameter of 400 nm or more existing in a 5 μm × 5 μm region in the cross section of the single-layer type photosensitive layer” is also referred to as “the number of aggregates (400)”.

Here, the “cross section of the photosensitive layer” is observed as follows.
First, for example, using a cutting machine (for example, Ultracut UCT (manufactured by Leica)) using a diamond knife, cutting is performed on the surface including the rotation axis of the photoreceptor to obtain a measurement sample having a thickness of 0.2 μm. Next, with a transmission electron microscope (TEM, manufactured by Hitachi High-Technologies Corporation, model number: S-4800), a 5 μm × 5 μm region in the obtained measurement data was observed at a magnification of 10,000 times to obtain a photosensitive layer. A TEM image of the cross section is obtained. Similarly, measurement materials are prepared and observed by TEM at three locations in the axial direction of the photoconductor, four locations in the circumferential direction, and two locations in the thickness direction of the photosensitive layer (that is, a total of 24 locations).
Then, the maximum diameters of the aggregates of the charge generation material confirmed in the obtained TEM image (that is, the TEM image obtained by observing the 5 μm × 5 μm region) are measured. Among the number of aggregates having a maximum diameter of 400 nm or more in each TEM image, the largest number is defined as the “number of aggregates (400)”.
The “maximum diameter” refers to a width at which the interval between the parallel lines is maximum when the image of the aggregate of the charge generation material is sandwiched between two parallel lines.

  In the photoconductor according to this embodiment, the number of aggregates (400) is 10 or less, so that the reproducibility of fine lines is improved. The reason is not clear, but is estimated as follows.

  In the single-layer type photosensitive layer, unlike the function-separated type photosensitive layer, the charge generating material is dispersed throughout the photosensitive layer (that is, in the thickness direction of the photosensitive layer). Therefore, when the charge generation material aggregates, the aggregate may affect the charge transfer path in the photosensitive layer and affect the image quality. Specifically, for example, when a fine line image is formed, the line width may become thick, thin, or fluctuate, and fine line reproducibility may not be obtained.

On the other hand, in this embodiment, the number of aggregates (400) is 10 or less. Therefore, compared to the case where the number of aggregates (400) exceeds 10, it is presumed that the charge transfer path in the photosensitive layer is less affected and the reproducibility of fine lines is improved.
In addition, the number of aggregates (400) is preferably 10 or less, and more preferably 8 or less.

In the present embodiment, from the viewpoint of fine line reproducibility, the aggregate of charge generation materials having a maximum diameter of 600 nm or more present in a 5 μm × 5 μm region in the cross section of the single-layer type photosensitive layer is 5 or less. Is preferred. Hereinafter, the “number of aggregates of charge generation materials having a maximum diameter of 600 nm or more existing in a 5 μm × 5 μm region in the cross section of the single-layer type photosensitive layer” is also referred to as “number of aggregates (600)”. The number of “aggregates (600)” is determined in the same manner as the number of “aggregates (400)”.
The number of “aggregates (600)” is preferably 5 or less, more preferably 3 or less, from the viewpoint of fine line reproducibility.

In the present embodiment, from the viewpoint of fine line reproducibility, the aggregate of charge generation materials having a maximum diameter of 200 nm or more present in a 5 μm × 5 μm region in the cross section of the single-layer type photosensitive layer is 20 or less. Is preferred. Hereinafter, the “number of aggregates of charge generation materials having a maximum diameter of 200 nm or more present in a 5 μm × 5 μm region in the cross section of the single-layer type photosensitive layer” is also referred to as “number of aggregates (200)”. The number of “aggregates (200)” is determined in the same manner as the number of “aggregates (400)”.
The number of “aggregates (200)” is preferably 20 or less, more preferably 15 or less, from the viewpoint of fine line reproducibility.

Hereinafter, the electrophotographic photoreceptor according to the exemplary embodiment will be described in detail with reference to the drawings.
FIG. 1 schematically shows a partial cross section of an electrophotographic photosensitive member 7 according to this embodiment.
The electrophotographic photoreceptor 7 shown in FIG. 1 includes, for example, a conductive substrate 3, and a single-layer type photosensitive layer 2 is provided on the conductive substrate 3.
In addition, you may provide another layer as needed. Examples of the other layers include an undercoat layer provided between the conductive substrate 3 and the single-layer type photosensitive layer 2 and a protective layer provided on the single-layer type photosensitive layer 2.

  Hereinafter, as an example of the electrophotographic photoreceptor according to the exemplary embodiment, each layer of the photoreceptor 7 illustrated in FIG. 1 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. A method of roughening with particles dispersed in the layer may also be 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.

(Single layer type photosensitive layer)
The single-layer type photosensitive layer includes at least a binder resin and a charge generation material, and may include an electron transport material, a hole transport material, and other additives as necessary.
As described above, the number of aggregates (400) is 10 or less.

-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 Resins, poly-N-vinylcarbazole, polysilane and the like can be mentioned. These binder resins may be used alone or in combination of two or more.

Of the binder resins, polycarbonate resins and polyarylate resins are preferable.
Further, from the viewpoint of film formability of the photosensitive layer, it is preferable to use at least one of a polycarbonate resin having a viscosity average molecular weight of 30,000 to 80,000 and a polyarylate resin having a viscosity average molecular weight of 30,000 to 80,000.

In addition, as a measuring method of the viscosity average molecular weight of polycarbonate resin, it measures by the following method, for example. 1 g of resin was dissolved in 100 cm ³ of methylene chloride, and its specific viscosity ηsp was measured with an Ubbelohde viscometer in a measurement environment at 25 ° C., and a relational expression of ηsp / c = [η] +0.45 [η] ² c ( However c is determined the concentration (g / cm ³⁾ than the intrinsic viscosity [η] ^(cm 3 / g), the equations given by H.Schnell, [η] = 1.23 × ¹⁰ -4 ^{Mv 0.83} The viscosity average molecular weight Mv is obtained from the relational expression of

  The content of the binder resin with respect to the total solid content of the photosensitive layer may be 35% by mass or more and 60% by mass or less, and preferably 20% by mass or more and 35% by mass or less.

-Charge generation material-
Examples of the charge generating material include azo pigments such as bisazo and trisazo; fused aromatic pigments such as dibromoanthanthrone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide;

  Among these, in order to cope with near-infrared laser exposure, it is preferable to use a metal phthalocyanine pigment or a metal-free phthalocyanine pigment as the charge generation material. Specifically, for example, hydroxygallium phthalocyanine disclosed in JP-A-5-263007, JP-A-5-279591, etc .; chlorogallium phthalocyanine disclosed in JP-A-5-98181; Examples thereof include dichlorotin phthalocyanine disclosed in JP-A No. 140472, JP-A-5-140473, and titanyl phthalocyanine disclosed in JP-A-4-189873.

Among these, as the charge generation material, at least one selected from hydroxygallium phthalocyanine pigments and chlorogallium phthalocyanine pigments is preferably used.
Only one type of charge generation material may be used, or two or more types may be used in combination.

Hydroxygallium phthalocyanine pigment The hydroxygallium phthalocyanine pigment is not particularly limited, but a V-type hydroxygallium phthalocyanine pigment is preferable from the viewpoint of increasing the sensitivity of the photoreceptor.
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. It is preferable from the 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 or more and 839 nm or less preferably has an average particle diameter in a specific range and a BET specific surface area in a specific range. Specifically, the average particle size is preferably 0.20 μm or less, and more preferably 0.01 μm or more and 0.15 μm or less. On the other hand, the BET specific surface area is preferably 45 m ² / g or more, more preferably 50 m ² / g or more, and particularly preferably 55 m ² / g or more and 120 m ² / g or less. 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 is less than 45 m ² / g, the pigment particles may be coarsened or aggregates of the pigment particles may be formed. In some cases, defects such as dispersibility, sensitivity, chargeability, and dark attenuation characteristics are likely to occur, which may cause image quality defects.

  The maximum particle size (maximum primary particle size) of the hydroxygallium phthalocyanine pigment is preferably 1.2 μm or less, more preferably 1.0 μm or less, and 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 due to exposure of the photoreceptor to a fluorescent lamp or the like, and 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 CuKα characteristic X-rays. V-type having a diffraction peak in

Chlorogallium phthalocyanine pigment There is no particular limitation on the chlorogallium phthalocyanine pigment, but a Bragg angle (2θ ± 0.2 °) of 7.4 °, 16.6 ° can be obtained which provides excellent sensitivity as an electrophotographic photosensitive material. , Preferably having diffraction peaks at 25.5 ° 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 is preferably from 0.5% by weight to 10% by weight, more preferably from 1% by weight to 7% by weight, more preferably from 1% by weight to 5% by weight, based on the entire photosensitive layer. A mass% or less is more preferable.

-Hole transport material-
Although there is no restriction | limiting in particular as a hole transport material, For example, oxadiazole derivatives, such as 2, 5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole; Pyrazoline derivatives such as phenyl-pyrazoline, 1- [pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline; triphenylamine, N, N′-bis (3 Aromatic tertiary amino compounds such as 4-dimethylphenyl) biphenyl-4-amine, tri (p-methylphenyl) aminyl-4-amine, dibenzylaniline; N, N′-bis (3-methylphenyl)- Aromatic tertiary diamino compounds such as N, N'-diphenylbenzidine, 3- (4'-dimethylaminophenyl) -5,6-di- (4'-methoxyphene) 1) 1,2,4-triazine derivatives such as 1,2,4-triazine; hydrazone derivatives such as 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone; quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline Benzofuran derivatives such as 6-hydroxy-2,3-di (p-methoxyphenyl) benzofuran; α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N-diphenylaniline; enamine derivatives; N -Carbazole derivatives such as ethyl carbazole; poly-N-vinyl carbazole and derivatives thereof; polymers having groups composed of the above-described compounds in the main chain or side chain; These hole transport materials may be used alone or in combination of two or more.

  Specific examples of the hole transport material include, for example, a compound represented by the following general formula (B-1), a compound represented by the following general formula (B-2), and the following general formula (B-3). Compounds. Further, specific examples of the hole transport material include compounds represented by the following general formula (1). Among these, from the viewpoint of charge mobility, it is preferable to use a hole transport material represented by the following general formula (1).

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 ), 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. Examples of the substituent include 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 general 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 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 are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a carbon number. An amino group substituted with 1 or more and 2 or less alkyl groups, a substituted or unsubstituted aryl group, -C (R ^B11 ) = C (R ^B12 ) (R ^B13 ), or -CH = CH-CH = C (R ^B14 ) (R ^B15 ), 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.

In general formula (B-3), R ^B16 and R ^{B16 ′} 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 an alkoxy having 1 to 5 carbon atoms. Group. R ^B17 , R ^{B17 ′} , R ^B18 , and R ^{B18 ′} may be the same or different and are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a carbon number. An amino group substituted with 1 or more and 2 or less alkyl groups, a substituted or unsubstituted aryl group, -C (R ^B19 ) = C (R ^B20 ) (R ^B21 ), or -CH = CH-CH = C (R ^B22 ) (R ^B23 ), and R ^{B19 to} R ^B23 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. m14, m15, n14 and n15 each independently represent an integer of 0 or more and 2 or less.

Here, among the compound represented by the general formula (B-1), the compound represented by the general formula (B-2), and the compound represented by the general formula (B-3), in particular, “—C ₆ H ₄ -CH = CH-CH = C (R ^B6 ) (R ^B7 ) "and the compound represented by the general formula (B-1), and" -CH = CH-CH = C (R ^B14 ) (R ^B15 ) " A compound represented by the general formula (B-2) having the formula:

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.
Among 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 or a 2,4-dimethylphenyl group; -A phenyl group substituted with a lower alkoxy group such as a methoxyphenyl group; a phenyl group substituted with a halogen atom such as a p-chlorophenyl group;
Examples of the substituent that can be substituted on the phenyl group include a lower alkyl group, a lower alkoxy group, and a halogen atom represented by R ^{1 to} R ⁶ .

Among the hole transport materials of the general formula (1), a hole transport material in which m and n are 1 is preferable from the viewpoint of increasing sensitivity, and R ^{1 to} R ⁶ are each independently a hydrogen atom or a lower alkyl group. Or a hole transport material which represents an alkoxy group and m and n are 1.

  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-PhO : Phenoxy group substituted at 4-position of phenyl group

The hole transport material of General formula (1) may be used individually by 1 type, and may be used in combination of 2 or more type. Moreover, when using the hole transport material represented by General formula (1), you may use together with hole transport materials other than the hole transport material represented by General formula (1).
In addition, as content in containing other hole transport materials other than the hole transport material of Formula (1), the range of 25 mass% or less is mentioned with respect to the whole hole transport material, for example.

The content of the hole transport material is preferably 10% by mass to 98% by mass with respect to the binder resin, preferably 60% by mass to 95% by mass, and more preferably 70% by mass to 90% by mass. .
In addition, content of this hole transport material is content of those whole hole transport materials, when two or more types of hole transport materials are used together.

-Electron transport material-
The electron transport material is not particularly limited as the electron transport material, but, for example, quinone compounds such as chloranil and bromoanil; tetracyanoquinodimethane compounds; 2,4,7-trinitrofluorenone, 9-dicyanomethylene Fluorenone compounds such as octyl-9-fluorenone-4-carboxylate, octyl 9-fluorenone-4-carboxylate, 2,4,5,7-tetranitro-9-fluorenone; 2- (4-biphenyl) -5- ( 4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4-oxadiazole, 2,5-bis (4-diethylaminophenyl) Oxadiazole compounds such as 1,3,4-oxadiazole; xanthone compounds; thiophene compounds; 3,3′-di-tert-pent Dinaphthoquinone compounds such as ru-dinaphthoquinone; 3,3′-di-tert-butyl-5,5′-dimethyldiphenoquinone, 3,3 ′, 5,5′-tetra-tert-butyl-4,4 Examples include diphenoquinone compounds such as'-diphenoquinone; polymers having groups composed of the above-described compounds in the main chain or side chain; and the like. These electron transport materials may be used alone or in combination of two or more.

Among these, a fluorenone compound is preferable in terms of increasing sensitivity, and among the fluorenone compounds, a compound represented by the following general formula (2) is preferable.
Hereinafter, the electron transport material represented by the following general formula (2) will be described.

In 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 An aralkyl group is shown. R ¹⁸ represents an alkyl group, a group represented by —L ¹⁹ —O—R ²⁰ , an aryl group, or an aralkyl group. ^{However, L 19} represents an alkylene ^{group, R 20} represents an alkyl 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. Among these, as the aryl group represented by R ^{11 to} R ¹⁷ , a phenyl group is preferable.
In the general formula (2), examples of the aralkyl group represented by R ^{11 to} R ¹⁷ include a benzyl group, a phenethyl group, and a phenylpropyl group.

In general formula (2), examples of the alkyl group represented by R ¹⁸ include a linear alkyl group having 1 to 12 carbon atoms (preferably 5 to 10 carbon atoms), and 3 to 10 carbon atoms (preferably Is a branched alkyl group having 5 to 10 carbon atoms.
Examples of the linear alkyl group having 1 to 12 carbon atoms include, for example, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n -An octyl group, n-nonyl group, n-decyl, n-undecyl, n-dodecyl group etc. are mentioned.
Examples of the branched alkyl group having 3 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), 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 linear or branched alkylene groups having 1 to 12 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 alkyl group represented by R ²⁰ include the same groups as the alkyl groups represented by R ^{11 to} R ¹⁷ .

In the general formula (2), examples of the aryl group represented by R ¹⁸ include a phenyl group, a methylphenyl group, a dimethylphenyl group, and an ethylphenyl group.
The aryl group represented by R ¹⁸ is preferably an alkyl-substituted aryl group substituted with an alkyl group from the viewpoint of solubility. Examples of the alkyl group of the alkyl-substituted aryl group include the same groups as the alkyl groups represented by R ^{11 to} R ¹⁷ .

In general formula (2), examples of the aralkyl group represented by R ¹⁸ include a group represented by -L ²¹ -Ar. ^{However, L 21} represents an alkylene group, Ar represents an aryl group.
Examples of the alkylene group represented by L ²¹ include linear or branched alkylene groups having 1 to 12 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, a dimethylphenyl group and an ethylphenyl group.

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

As the electron transporting material of the formula (2), from the viewpoint of high sensitivity, electron transporting materials R ¹⁸ represents a branched alkyl group or an aralkyl group having 5 to 10 carbon atoms are preferred, in particular, R ¹¹ ~ An electron transport material in which R ¹⁷ independently represents a hydrogen atom, a halogen atom, or an alkyl group, and R ¹⁸ represents a branched alkyl group or an aralkyl group having 5 to 10 carbon atoms is preferable.

  Hereinafter, although the exemplary compound of the electron transport material of 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 group

The electron transport material of General formula (2) may be used individually by 1 type, and may be used in combination of 2 or more type. Moreover, when using the electron transport material represented by General formula (2), you may use together with electron transport materials other than the electron transport material represented by General formula (2).
In addition, as content in the case of containing electron transport materials other than the electron transport material represented by General formula (2), it is preferable that it is the range of 10 mass% or less with respect to the whole electron transport material.

The content of the electron transport material is preferably 10% by mass to 70% by mass with respect to the binder resin, preferably 15% by mass to 50% by mass, and more preferably 20% by mass to 40% by mass.
In addition, content of this electron transport material is content of the whole of those electron transport materials, when two or more types of electron transport materials are used together.

-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, and 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 a surfactant, 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 photosensitive layer-
The photosensitive layer is formed using a coating solution for forming a photosensitive layer in which the above components are added to a solvent. Specifically, after adding the above components to a solvent, the photosensitive layer forming coating solution obtained by dispersing the particles is applied onto a conductive substrate (or on the undercoat layer if it has an undercoat layer). And dried to form a single-layer type photosensitive layer.

  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 liquid for forming a photosensitive layer, a media dispersing machine such as a ball mill, a vibrating ball mill, an attritor, a sand mill, a horizontal sand mill, a dyno mill, a stirring, an ultrasonic dispersing machine, Medialess dispersers such as roll mills and 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.
Among these, it is preferable to use a medialess disperser such as a high-pressure homogenizer rather than a media disperser such as a sand mill because the absorbance ratio A1000 / A830 can be easily controlled to 25 or less.

  Examples of the method for applying the photosensitive layer forming coating solution include 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.

Here, as a method of controlling the number of aggregates (400), for example, in the process of preparing a coating solution for forming a photosensitive layer, a mixture containing a charge generating material and a solvent is dispersed by a disperser such as a sand mill. The method of adding binder resin etc. later is mentioned.
Specifically, for example, a first dispersion step of dispersing the charge generation material in a solvent, a binder resin and other components as necessary in the first dispersion obtained in the first dispersion step. A coating solution for forming a photosensitive layer is prepared through a second dispersion step of adding and dispersing in the first dispersion. In addition, as another component added as needed, the above-mentioned hole transport material, electron transport material, other additives, etc. are mentioned, for example.
When preparing the photosensitive layer forming coating solution through the first dispersion step and the second dispersion step, the dispersion method and dispersion conditions in the first dispersion step and the second dispersion step are also adjusted. The number of aggregates (400) is controlled. Examples of the dispersion conditions include dispersion time, dispersion temperature, shear stress, liquid viscosity, and the like.
The method of controlling the number of aggregates (600) and the method of controlling the number of aggregates (200) are the same as the method of controlling the number of aggregates (400).

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

(Other layers)
-Undercoat layer-
In the photoreceptor according to this embodiment, a single-layer type photosensitive layer may be directly provided on a conductive substrate, but the present invention is not limited to this, and the single-layer type photosensitive layer is provided on the conductive substrate via an undercoat layer. A photosensitive layer may be provided.
The undercoat layer is not particularly limited, and includes, for example, a layer containing a binder resin and a charge transport material (for example, the hole transport material described above), a binder resin and inorganic particles (for example, metal oxide particles). A layer containing a binder resin and resin particles, a layer formed of a cured film (crosslinked film), a layer containing various particles in the cured film, and the like.
Examples of the binder resin contained in the undercoat layer include alcohol-soluble polyamide resins and polyvinyl resins.
The undercoat layer is formed by, for example, applying an undercoat layer forming coating solution onto a conductive substrate by a dip coating method and drying it.
As a film thickness of an undercoat layer, the range of 0.1 micrometer or more and 30 micrometers or less is mentioned, for example.

-Protective layer-
In the photoreceptor according to the present exemplary embodiment, a protective layer may be provided on the photosensitive layer as an outermost layer as necessary.
Although a protective layer is not specifically limited, For example, the layer comprised by the cured film (crosslinked film) is mentioned.

  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.

  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 of apparatus; apparatus 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 electrophotographic photosensitive member is irradiated with a charge eliminating light before charging. A known image forming apparatus such as an apparatus provided with an electrophotographic photoreceptor heating member for raising the temperature of the electrophotographic photoreceptor 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 to the surface, and a primary transfer that primarily transfers the toner image formed on the surface of the electrophotographic photosensitive member to the surface of the intermediate transfer body. A configuration including a transfer unit and a secondary transfer unit that secondarily transfers the toner image transferred onto the surface of the intermediate transfer member onto the surface of the recording medium is applied.

  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).

  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) 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. In addition, the main part shown to a figure is demonstrated and the description is abbreviate | omitted about others.

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.

-Developer-
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-
Examples of the transfer device 40 include known transfer chargers such as a contact transfer charger using a belt, a roller, a film, a rubber blade, and the like, a scorotron transfer charger using a corona discharge, and 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. Unless otherwise specified, “part” means “part by mass” and “%” means “mass%”.

<Example 1>
-Production of coating solution for forming photosensitive layer-
Bragg angle (2θ ± 0.2 °) of X-ray diffraction spectrum using Cukα characteristic X-ray as charge generation material is at least 7.3 °, 16.0 °, 24.9 °, 8.0 ° A sand mill using glass beads having a diameter of 1 mmφ while maintaining a mixture of 1.2 parts of a hydroxygallium phthalocyanine pigment having a diffraction peak (hereinafter also referred to as “HOGaPC”) and 100 parts of tetrahydrofuran as a solvent at 25 ° C. For 1 hour (that is, the first dispersion time in the first dispersion step is set to 1 hour) to obtain a first dispersion.

  In the first dispersion, 46.8 parts of bisphenol Z polycarbonate resin (viscosity average molecular weight: 50,000) as a binder resin and an exemplary compound (2-1) that is an electron transport material represented by the general formula (2) ) 15 parts, 37 parts of exemplary compound (1-1) which is a hole transport material represented by the general formula (1), and 150 parts of tetrahydrofuran as a solvent, while maintaining at 25 ° C., Dispersion was performed for 6 hours in a sand mill using glass beads having a diameter of 1 mmφ (that is, the second dispersion time in the second dispersion step was 6 hours) to obtain a coating solution for forming a photosensitive layer.

-Formation of photosensitive layer-
The resulting coating solution for forming a photosensitive layer was applied to an aluminum substrate having a diameter of 30 mm and a length of 244.5 mm by a dip coating method while controlling at 28 ° C., followed by drying and curing at 140 ° C. for 30 minutes. A single-layer type photosensitive layer having a thickness of 30 μm was formed.
Through the above steps, the electrophotographic photosensitive member in Example 1 was produced.

<Example 2>
An electrophotographic photosensitive member in Example 2 was produced in the same manner as in Example 1 except that the first dispersion time and the second dispersion time were as shown in Table 1 in the production of the coating solution for forming the photosensitive layer. did.

<Examples 3 to 4>
In the production of the coating solution for forming a photosensitive layer, the type of the charge generating material used is an X-ray diffraction spectrum Bragg angle (2θ ± 0.2 °) using Cukα characteristic X-ray of at least 7.4 °, 16. Except for changing to a chlorogallium phthalocyanine pigment (hereinafter also referred to as “ClGaPC”) having diffraction peaks at 6 °, 25.5 °, and 28.3 °, the same as in Example 1 and Example 2, respectively. The electrophotographic photosensitive member in Example 3 and the electrophotographic photosensitive member in Example 4 were produced.

<Examples 5-6>
In the production of the coating solution for forming a photosensitive layer, the type of the charge generating material used is an X-ray diffraction spectrum Bragg angle (2θ ± 0.2 °) using Cukα characteristic X-ray of at least 7.3 °, 16. Bragg angle (2θ ± 0.2 °) of X-ray diffraction spectrum using hydroxygallium phthalocyanine pigment (HOGaPC) having diffraction peaks at 0 °, 24.9 °, and 28.0 ° and Cukα characteristic X-ray And a 1: 1 (mass ratio HOGaPC: ClGaPC) mixture of chlorogallium phthalocyanine pigment (ClGaPC) having diffraction peaks at positions of at least 7.4 °, 16.6 °, 25.5 °, 28.3 ° Except that, an electrophotographic photosensitive member in Example 5 and an electrophotographic photosensitive member in Example 6 were produced in the same manner as in Example 1 and Example 2, respectively.

<Example 7>
An electrophotographic photosensitive member in Example 7 is produced in the same manner as in Example 1 except that the first dispersion time and the second dispersion time are set as shown in Table 1 in the production of the photosensitive layer forming coating solution. did.

<Example 8>
In the production of the coating solution for forming a photosensitive layer, the addition amount of tetrahydrofuran in the first dispersion step was changed from 100 parts to 60 parts, and the addition amount of tetrahydrofuran in the second dispersion process was changed from 150 parts to 190 parts. In the same manner as in Example 1, an electrophotographic photosensitive member in Example 8 was produced.

<Example 9>
In the production of the coating liquid for forming a photosensitive layer, the charge generation material addition amount in the first dispersion step is changed from 1.2 parts to 3 parts, and the hole transport material addition amount in the second dispersion step is 37 parts. The electrophotographic photosensitive member in Example 9 was produced in the same manner as in Example 1 except that the amount of the electron transport material was changed from 15 parts to 20 parts.

<Example 10>
In the production of the coating liquid for forming the photosensitive layer, the type of the electron transport material is changed to the exemplified compound (2-2) which is the electron transport material represented by the general formula (2), and the type of the hole transport material is changed to the above. An electrophotographic photoreceptor in Example 10 was produced in the same manner as in Example 1 except that the compound was changed to the exemplified compound (1-2) which is a hole transport material represented by the general formula (1).

<Comparative Examples 1-3>
The electrophotographic photosensitive member in Comparative Example 1 was prepared in the same manner as in Example 1 except that the first dispersion time and the second dispersion time were as shown in Table 1 in the production of the coating solution for forming the photosensitive layer. The electrophotographic photoreceptor in Comparative Example 2 and the electrophotographic photoreceptor in Comparative Example 3 were produced.

<Comparative example 4>
An electrophotographic photosensitive member in Comparative Example 4 was produced in the same manner as in Example 3 except that the first dispersion time and the second dispersion time were as shown in Table 1 in the production of the coating solution for forming the photosensitive layer. did

<Comparative Example 5>
An electrophotographic photosensitive member in Comparative Example 5 was produced in the same manner as in Example 5 except that the first dispersion time and the second dispersion time were as shown in Table 1 in the production of the coating solution for forming the photosensitive layer. did

  In the obtained photoreceptor, the number of aggregates (200) (“aggregate (200)” in the table), the number of aggregates (400) (“aggregate (400)” in the table), and aggregates The number of (600) (“aggregate (600)” in the table) is shown in Table 1.

<Evaluation>
The following evaluations were performed on the obtained electrophotographic photoreceptors. The results are shown in Table 1.

-Image quality evaluation (Evaluation of fine line reproducibility)-
The image quality was evaluated using a modified machine in which the obtained electrophotographic photosensitive member was mounted on Brother HL2270DW.
Specifically, using the modified machine, an image for thin line evaluation having 1 dot line (1 dot line) and 2 dot line (2 dot line) on the first sheet in an environment of 8 ° C. and 80% RH (in the table) After that, after forming 300,000 continuous half-tone images with an A4 lateral feed (short-side feed), 1 dot line (1 dot line) and 2 dot line (2 An image for fine line evaluation (“300,000 in the table”) having dot lines) was formed, and the fine line reproducibility of each fine line image was evaluated according to the following evaluation criteria.

-Evaluation criteria-
G1: No thinning of 1 dot line and 2 dot line G2: Thinning of 50% or less occurs in 2 dot line G3: Thinning exceeding 50% occurs in 2 dot line, 1 dot line is interrupted

  From the above results, it can be seen that the photoconductor of this example has improved fine line reproducibility compared to the photoconductor of the comparative example.

2 photosensitive layer, 3 conductive substrate, 7 electrophotographic photosensitive member, 8 charging device, 9 exposure device, 11 developing device, 13 cleaning device, 14 lubricant, 40 transfer device, 50 intermediate transfer member, 100 image forming device, 120 Image forming apparatus, 131 cleaning blade, 132 fibrous member, 133 fibrous member, 300 process cartridge

Claims (11)

A conductive substrate;
A single-layer type photosensitive layer provided on the conductive substrate and containing a binder resin and a charge generation material, and having a maximum diameter existing in a region of 5 μm × 5 μm in a cross section of the single-layer type photosensitive layer A single-layer type photosensitive layer having 10 or less aggregates of the charge generation material of 400 nm or more;
An electrophotographic photosensitive member having:   2. The electrophotographic photosensitive member according to claim 1, wherein the number of aggregates of the charge generation material having a maximum diameter of 600 nm or more present in a region of 5 μm × 5 μm in a cross section of the single-layer type photosensitive layer is 5 or less.   The electrophotographic photosensitive member according to claim 1, wherein the charge generation material contains at least one of a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment.   The electrophotographic photosensitive member according to claim 3, wherein the content of the charge generating material is 0.5% by mass or more and 10% by mass or less with respect to the entire single-layer type photosensitive layer.   5. The electrophotographic photosensitive member according to claim 4, wherein the content of the charge generation material is 1% by mass or more and 7% by mass or less with respect to the entire single-layer type photosensitive layer.   The electrophotographic photosensitive member according to claim 1, wherein the single-layer type photosensitive layer contains a hole transport material. The electrophotographic photosensitive member according to claim 6, wherein the hole transport material is a hole transport material represented by the following general formula (1).

(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.)   The electrophotographic photosensitive member according to claim 1, wherein the single-layer type photosensitive layer contains an electron transport material. The electrophotographic photosensitive member according to claim 8, wherein the electron transport material is an electron transport material represented by the following general formula (2).

(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, R ¹⁸ represents an alkyl group, a group represented by —L ¹⁹ —O—R ²⁰ , an aryl group, or an aralkyl group, wherein L ¹⁹ represents an alkylene group, and R ²⁰ represents an alkyl group. Is shown.) The electrophotographic photosensitive member according to any one of claims 1 to 9,
A process cartridge that can be attached to and detached from an image forming apparatus. The electrophotographic photosensitive member according to any one of claims 1 to 9,
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: