JP2013047751A - Electrophotographic photoreceptor, process cartridge, image forming apparatus, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor in which wear on the surface is suppressed.SOLUTION: The electrophotographic photoreceptor includes a support body 2 and one or more layers of a base coating layer, a charge generating layer 5 and a charge transporting layer 6 including at least a photosensitive layer 3, formed on the support body 2. The charge transporting layer 6 disposed at the farthest side from the support body 2 contains a polycarbonate resin satisfying the formula of 0.45≤(Mv/Mw)≤0.55 and at least two kinds of charge transporting materials containing at least a compound having a butadiene structure. In the above formula, Mv and Mw represent a viscosity average molecular weight and a weight average molecular weight, respectively.

Description

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

In Patent Document 1, in a photoreceptor having a photosensitive layer containing a charge generating substance, a charge transporting substance, and a binder resin on a conductive substrate, the width of the molecular weight distribution of the binder resin is expressed, and z average molecular weight Mz and Disclosed is an electrophotographic photoreceptor, wherein a dispersion degree d ₁ (d ₁ = Mz / Mw) represented by a ratio to the weight average molecular weight Mw is 1.6 or more in terms of polystyrene standard. Has been.

JP 2001-265019 A

  The main object of the present invention is to provide an electrophotographic photoreceptor in which wear on the surface is suppressed.

In order to achieve the above object, the following invention is provided.
The invention according to claim 1
A support;
One or more layers provided on the support and including at least a photosensitive layer;
With
Of the one or more layers, the outermost surface layer disposed on the side farthest from the support is two or more kinds of charge transports including at least a polycarbonate resin satisfying the following formula (1) and a compound having a butadiene structure. And an electrophotographic photoreceptor containing the material.
Formula (1): 0.45 ≦ (Mv / Mw) ≦ 0.55
In the above formula (1), Mv represents a viscosity average molecular weight, and Mw represents a weight average molecular weight.

The invention according to claim 2
The electrophotographic photosensitive member according to claim 1, wherein the compound having a butadiene structure is a compound having three butadiene structures in one molecule.

The invention according to claim 3
The electrophotographic photosensitive member according to claim 1 or 2,
A charging means for charging the surface of the electrophotographic photosensitive member, a developing means for developing a latent electrostatic image formed on the electrophotographic photosensitive member with a developer to form a toner image, and a surface of the electrophotographic photosensitive member. At least one selected from the group consisting of toner removing means for removing residual toner;
Is a process cartridge.

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 exposing the surface of the charged electrophotographic photosensitive member to form an electrostatic latent image;
Developing means for developing the electrostatic latent image with a developer to form a toner image;
Transfer means for transferring the toner image to a transfer medium;
An image forming apparatus having

The invention according to claim 5
A charging step for charging the surface of the electrophotographic photosensitive member according to claim 1 or 2,
An electrostatic latent image forming step of forming an electrostatic latent image by exposing the surface of the charged electrophotographic photosensitive member;
A developing step of developing the electrostatic latent image with a developer to form a toner image;
A transfer step of transferring the toner image to a transfer medium;
Is an image forming method.

  According to the first aspect of the present invention, compared to the case where the outermost surface layer does not contain the polycarbonate resin satisfying the formula (1) or the charge transport material, wear on the surface of the electrophotographic photosensitive member is suppressed. The

  According to the second aspect of the present invention, compared to the case where the outermost surface layer does not contain a compound having three butadiene structures in one molecule, a decrease in electrical characteristics of the electrophotographic photosensitive member is suppressed.

  According to the invention of claim 3, a good image can be obtained over a long period of time as compared with the case where the outermost surface layer in the electrophotographic photosensitive member does not contain the polycarbonate resin satisfying the formula (1) or the charge transporting material. It is formed.

  According to the invention of claim 4, a good image can be obtained over a long period of time as compared with the case where the outermost surface layer in the electrophotographic photosensitive member does not contain the polycarbonate resin or the charge transport material satisfying the formula (1). It is formed.

  According to the invention of claim 5, a good image can be obtained over a long period of time as compared with a case where the outermost surface layer uses a polycarbonate resin satisfying the formula (1) or an electrophotographic photoreceptor not containing the charge transport material. Is formed.

It is the schematic which shows the cross section of a part of the electrophotographic photoreceptor which concerns on this embodiment. 1 is a schematic diagram illustrating a basic configuration of an image forming apparatus according to a first embodiment. It is the schematic which shows the basic composition of the image forming apparatus of 2nd Embodiment. It is the schematic which shows the basic composition of an example of a process cartridge.

  Hereinafter, embodiments will be described in detail. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description may be omitted.

The electrophotographic photoreceptor of this embodiment (hereinafter sometimes referred to as “photoreceptor”) includes a support and one or more layers formed on the support and including at least a photosensitive layer. And among the one or more layers, the outermost surface layer disposed on the side farthest from the support contains a polycarbonate resin satisfying the following formula (1) and two or more kinds of charge transport materials, At least one of the two or more kinds of charge transport materials is a compound having a butadiene structure (hereinafter sometimes referred to as “butadiene compound”).
Formula (1): 0.45 ≦ (Mv / Mw) ≦ 0.55
In the above formula (1), Mv represents a viscosity average molecular weight, and Mw represents a weight average molecular weight.

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

  Moreover, the said weight average molecular weight Mw is calculated | required, for example by measuring with a gel permeation chromatography (GPC). Specifically, the molecular weight measurement by GPC uses, for example, Tosoh GPC / HLC-8120 as a measuring device, Tosoh column TSKgel SuperHM-M (15 cm) as a column, and THF (tetrahydrofuran) as a solvent. To do. From this measurement result, the weight average molecular weight Mw is calculated using a molecular weight calibration curve prepared with a monodisperse polystyrene standard sample.

  Since the photoconductor according to the present embodiment has the above-described configuration, the surface of the electrophotographic photoconductor is compared with the case where the outermost surface layer does not contain the polycarbonate resin satisfying the formula (1) or the charge transport material. Wear is suppressed. The reason is not clear, but is presumed as follows.

  The (Mv / Mw) value is a value obtained by dividing the molecular weight determined from the viscosity by the weight average molecular weight as described above. Therefore, when comparing resins having the same number of repeating units, a resin having a large (Mv / Mw) value is considered to be a resin having a relatively large viscosity as compared with a small resin. As described above, a resin having a high viscosity has a larger intermolecular interaction than a resin having a low viscosity. Therefore, even when a force is applied from the outside, molecules are not easily separated from each other, and a part of the resin is torn off. It is considered difficult.

Therefore, when the polycarbonate resin having the (Mv / Mw) value in the above range is used as in this embodiment, the surface of the resin is present in the presence of an abrasive, for example, compared to the case of using a resin smaller than the above range. However, it is presumed that the resin is less likely to wear even if it rubs against other members.
In addition, it is estimated that manufacture and acquisition are difficult for the polycarbonate resin whose said (Mv / Mw) value is larger than the said range.

  In this embodiment, the outermost surface layer contains not only a polycarbonate resin but also a charge transport material. Therefore, even when the polycarbonate resin alone is difficult to wear, if the compatibility between the resin and the charge transporting material is low, the charge transporting material may crystallize and precipitate, which may easily cause wear. . In particular, in this embodiment, the (Mv / Mw) value of the resin is in the above range, and the intermolecular interaction of the resin is larger than that in the range smaller than the above range. Therefore, since the compatibility between the resins is too large, the compatibility between the resin and the charge transport material is relatively lowered, and the charge (Mv / Mw) is smaller than that when the same (Mv / Mw) value is used even when the same charge transport material is used. It is conceivable that the transport material is likely to precipitate.

  On the other hand, in this embodiment, two or more types of charge transport materials are used as the charge transport material, and a butadiene compound is used as at least one of the two or more types of charge transport materials. That is, crystallization is suppressed by using two or more kinds of charge transport materials while ensuring compatibility with the resin by using a butadiene compound having a high affinity with the polycarbonate resin. Therefore, in this embodiment, as described above, the (Mv / Mw) value is in the above range, and it is considered that the precipitation of the charge transport material is suppressed even when a polycarbonate resin having a large intermolecular interaction is used.

As described above, in the present embodiment, it is presumed that the wear on the surface is suppressed by suppressing the precipitation of the charge transport material while using the resin having a large intermolecular interaction in the outermost surface layer. Therefore, in this embodiment, an abrasive is present on the surface of the outermost layer, and other members (for example, a toner removing unit, a developing unit, a transfer medium, etc.) rub against the surface of the photoreceptor via the abrasive. Even so, wear due to the abrasive is suppressed. As said abrasive | polishing agent, the abrasive | polishing agent (for example, silica, cerium oxide etc.) etc. which are contained in a toner other than the calcium carbonate etc. which are contained in the paper used as a to-be-transferred medium, etc. are mentioned, for example.
The (Mv / Mw) value is 0.45 or more and 0.55 or less as described above.

  In the present embodiment, a compound having three butadiene structures in one molecule (hereinafter sometimes referred to as “tributadiene compound”) may be used as the butadiene compound. By using a tributadiene compound as a charge transport material, the hole transport property of the outermost surface layer is improved as compared with the case of using a compound having one or two butadiene structures, so that the electrical characteristics of the photoreceptor are good. (For example, the residual potential of the photoreceptor is reduced), and a good image is formed over a long period of time.

Since the photoconductor of this embodiment is hard to wear as described above, according to the process cartridge, the image forming apparatus, and the image forming method using the photoconductor of this embodiment, the photoconductor that does not satisfy the above conditions. As compared with the case of using, a good image is formed over a long period of time.
For example, when image formation is performed using a paper containing calcium carbonate as a transfer medium, the calcium carbonate powder may act as an abrasive as described above. In this embodiment, the surface of the photoreceptor is worn as described above. Therefore, a good image is formed over a long period. In particular, in a system in which a toner image formed on the surface of a photoconductor is directly transferred to a transfer medium without using an intermediate transfer body or the like (hereinafter sometimes referred to as “direct transfer system”), the transfer medium Calcium carbonate or the like contained in the paper used as the toner adheres to the surface of the photoreceptor and easily functions as an abrasive. Further, in a method of transferring a toner image formed on the surface of a photosensitive member to a transfer medium via an intermediate transfer member (hereinafter sometimes referred to as an “intermediate transfer method”), a sheet used as a transfer medium is used. It is considered that calcium carbonate or the like contained may adhere to the surface of the photoreceptor via the intermediate transfer member and function as an abrasive.
However, in the present embodiment, as described above, since the wear on the surface of the photoconductor hardly occurs, for example, even if the amount of calcium carbonate functioning as an abrasive increases, image degradation (for example, density unevenness due to wear on the photoconductor surface). Generation) is suppressed, and a good image is formed over a long period of time.

In addition, suppression of the image deterioration by using the photoconductor of the present embodiment is particularly effective in a contact charging method in which only a DC voltage is applied to the charging member and a non-contact charging method (that is, a method in which an AC voltage is applied). (When the electrical stress is small compared to the above), it is considered that it appears remarkably.
Hereinafter, the photoreceptor of this embodiment will be described in more detail.

<Electrophotographic photoreceptor>
FIG. 1 schematically shows a cross section of a part of the electrophotographic photosensitive member according to this embodiment. The electrophotographic photoreceptor 1 shown in FIG. 1 includes a function-separated type photosensitive layer 3 in which a charge generation layer 5 and a charge transport layer 6 are separately provided. An undercoat layer 4 is provided on a conductive support 2. The charge generation layer 5 and the charge transport layer 6 are stacked in this order.
In the electrophotographic photoreceptor 1 shown in FIG. 1, the conductive support 2 is the “support”, and the undercoat layer 4, the charge generation layer 5, and the charge transport layer 6 are “one containing at least a photosensitive layer”. The charge transport layer 6 is the outermost surface layer (the layer disposed on the side farthest from the conductive support 2). Moreover, although mentioned later for details, the electric charge transport layer 6 which is an outermost surface layer is comprised including specific polycarbonate resin and charge transport material.
In addition, in this specification, insulation means the range of 10 ¹² Ωcm or more in volume resistivity. On the other hand, the conductivity means a range of 10 ¹⁰ Ωcm or less in volume resistivity.
Hereinafter, each element of the photoreceptor 1 will be described.

-Conductive support-
Any conductive support 2 may be used as long as it is conventionally used. For example, metals such as aluminum, nickel, chromium, stainless steel, and plastic films provided with thin films such as aluminum, titanium, nickel, chromium, stainless steel, gold, vanadium, tin oxide, indium oxide, ITO, etc. Examples thereof include paper and plastic film coated or impregnated with an imparting agent.
The shape of the support 2 is not limited to a drum shape, and may be a sheet shape or a plate shape.

  When a metal pipe is used as the conductive support 2, the surface may remain as it is, or a process such as mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, wet honing, etc. is performed in advance. It may be.

-Undercoat layer-
The undercoat layer 4 is provided as necessary for the purpose of preventing light reflection on the surface of the support 2 and preventing inflow of unnecessary carriers from the support 2 to the photosensitive layer 3.
As the undercoat layer 4, metal powder such as aluminum, copper, nickel, silver, conductive metal oxide such as antimony oxide, indium oxide, tin oxide, zinc oxide, carbon fiber, carbon black, graphite powder, etc. And a conductive material dispersed in a binder resin and coated on the support 2.

The binder resin contained in the undercoat layer 4 includes acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, and polyvinyl chloride resin. , Polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, phenolic resins, phenol-formaldehyde resins, melamine resins, urethane resins and other known polymer resin compounds, charge transporting groups A charge transporting resin having a conductive property such as polyaniline is used.
When the undercoat layer 4 is formed, a coating solution in which the above components are added to a solvent (coating solution for forming the undercoat layer) is used. Examples of the solvent include organic solvents.

Examples of methods for applying the coating solution for forming the undercoat layer onto the support 2 include dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, and curtain coating. Can be mentioned.
The thickness of the undercoat layer 4 is preferably 15 μm or more, and more preferably 20 μm or more and 50 μm or less.

-Intermediate layer-
An intermediate layer (not shown) may be further provided on the undercoat layer 4 as necessary for improving the electrical characteristics, improving the image quality, improving the image quality maintenance, and improving the adhesion of the photosensitive layer. As the binder resin used for the intermediate layer, acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl In addition to polymer resins such as acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin, zirconium, titanium, aluminum, manganese, silicon atom, etc. And organometallic compounds containing
For forming the intermediate layer, for example, a coating solution in which the binder resin is dissolved in a solvent is used. As a coating method of the coating solution, known 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.
The thickness of the intermediate layer is set, for example, in the range of 0.1 μm to 3 μm. Further, this intermediate layer may be used as the undercoat layer 4.

-Charge generation layer-
The charge generation layer 5 is formed by dispersing a charge generation material in a binder resin.
As the charge generation material, phthalocyanine pigments such as metal-free phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, dichlorotin phthalocyanine, and titanyl phthalocyanine are used. In particular, the Bragg angle (2θ ± 0.2 °) with respect to CuKα characteristic X-rays Chlorogallium phthalocyanine crystal having strong diffraction peaks at least at 7.4 °, 16.6 °, 25.5 ° and 28.3 °, Bragg angle (2θ ± 0.2 °) to CuKα characteristic X-ray of at least 7. Metal-free phthalocyanine crystals having strong diffraction peaks at 7 °, 9.3 °, 16.9 °, 17.5 °, 22.4 ° and 28.8 °, Bragg angle (2θ ± 0. 2 °) at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25 Hydroxygallium phthalocyanine crystals having strong diffraction peaks at 1 ° and 28.3 °, Bragg angles (2θ ± 0.2 °) with respect to CuKα characteristic X-rays of at least 9.6 °, 24.1 ° and 27.2 ° A titanyl phthalocyanine crystal or the like having a strong diffraction peak is used. In addition, quinone pigments, perylene pigments, indigo pigments, bisbenzimidazole pigments, anthrone pigments, quinacridone pigments and the like are used as charge generation materials. These charge generation materials are used alone or in admixture of two or more.

Examples of the binder resin in the charge generation layer include polycarbonate resin such as bisphenol A type or bisphenol Z type, acrylic resin, methacrylic resin, polyarylate resin, polyester resin, polyvinyl chloride resin, polystyrene resin, acrylonitrile-styrene copolymer Combined resin, acrylonitrile-butadiene copolymer, polyvinyl acetate resin, polyvinyl formal resin, polysulfone resin, styrene-butadiene copolymer resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride resin, Silicone resin, phenol-formaldehyde resin, polyacrylamide resin, polyamide resin, poly-N-vinylcarbazole resin and the like are used. These binder resins are used alone or in combination of two or more.
The mixing ratio (mass ratio) of the charge generation material and the binder resin is, for example, in the range of 10: 1 to 1:10, depending on the material used.

When the charge generation layer 5 is formed, a coating solution in which the above components are added to a solvent is used.
In order to disperse the charge generation material in the binder resin, the coating liquid is subjected to a dispersion treatment. As the dispersing means, a media disperser such as a ball mill, a vibrating ball mill, an attritor or a sand mill, or a medialess disperser such as an agitator, an ultrasonic disperser, a roll mill or a high pressure homogenizer is used. Furthermore, examples of the high-pressure homogenizer include a liquid-liquid collision in a high-pressure state, a collision system that disperses the liquid-liquid by colliding with a liquid-wall, and a penetration system that disperses the fine liquid through a high-pressure state.

As a method for coating the coating solution for forming the charge generation layer thus obtained on the undercoat layer 4, 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. Method, curtain coating method and the like.
The thickness of the charge generation layer 5 is preferably set in the range of 0.01 μm to 5 μm, more preferably 0.05 μm to 2.0 μm.

-Charge transport layer-
As described above, the charge transport layer 6 contains, as at least a binder resin, a polycarbonate resin satisfying the above formula (1), and two or more kinds of charge transport materials containing at least a butadiene compound. Fluorine-containing resin particles (hereinafter sometimes referred to as “fluorine particles”) and other components may be included.

(Polycarbonate resin)
The polycarbonate resin is not particularly limited as long as it satisfies the formula (1). The (Mv / Mw) value in the formula (1) is considered to be determined by the structure of the repeating unit constituting the polycarbonate resin.
Specific examples of the polycarbonate resin satisfying the formula (1) include, for example, a polycarbonate resin having a repeating unit represented by the following general formula (2), and a repeating unit represented by the above general formula (2): And a copolymer having other repeating units.

In the general formula (2), R ¹ and R ² are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, or carbon. Represents an aryl group having a number of 6 or more and 12 or less.

Examples of other repeating units include a repeating unit represented by the following general formula (3), a repeating unit represented by the following general formula (4), and the like.
That is, the polycarbonate resin may be a copolymer including a repeating unit represented by the above general formula (2) and a repeating unit represented by the following general formula (3), and represented by the above general formula (2). The copolymer containing the repeating unit and the repeating unit represented by following General formula (4) may be sufficient.

Here, in the general formula (3), R ³ and R ⁴ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, or 6 or more carbon atoms. 12 or less aryl groups are represented.
In the general formula (4), R ⁵ and R ⁶ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, or 6 to 12 carbon atoms. The following aryl groups are represented.

  When the polycarbonate resin is a copolymer containing the repeating unit represented by the general formula (2) and the repeating unit represented by the general formula (3), the polycarbonate resin is represented by the general formula (2) in the polycarbonate resin. Examples of the content of the repeating unit include 5 mol% or more and 95 mol% or less, and may be 5 mol% or more and 50 mol% or less, or 15 mol% or more and 25 mol% or less. .

  When the polycarbonate resin is a copolymer composed of the repeating unit represented by the general formula (2) and the repeating unit represented by the general formula (4), the general formula ( As content of the repeating unit represented by 2), 5 mol% or more and 90 mol% or less are mentioned, for example, 5 mol% or more and 50 mol% or less may be mentioned, 15 mol% or more and 30 mol% or less There may be.

The polycarbonate resin is prepared by using, for example, a raw material such as a 4,4′-dihydroxybiphenyl compound represented by the following general formula (2 ′), polycondensation with a carbonate-forming compound such as phosgene, or a bisaryl carbonate. It is synthesized by a method such as transesterification.
Specifically, when synthesizing a polycarbonate resin composed of the repeating unit represented by the general formula (2) and the repeating unit represented by the general formula (3), for example, the following general formula (2 ′) A polycondensation with a carbonate ester-forming compound such as phosgene or an ester with a bisaryl carbonate using a 4,4′-dihydroxybiphenyl compound represented by the formula and a bisphenol compound represented by the following general formula (3 ′) as raw materials A polycarbonate resin is obtained by a method such as an exchange reaction.

Here in the general formula (2 ') and the general formula ^(3'), R ^1, R 2, ^{R 3,} and ^{R 4, R} 1 in each of the general formulas (2) and (3), The same as R ² , R ³ and R ⁴ .

  The viscosity average molecular weight of the polycarbonate resin satisfying the formula (1) is, for example, from 20,000 to 100,000, and may be from 30,000 to 8 “0000” or from 40,000 to 70,000.

The polycarbonate resin satisfying the formula (1) may be used alone or in combination of two or more. In addition, a resin other than the polycarbonate resin satisfying the above formula (1) (that is, other polycarbonate resin or other resin) is included as a binder resin component as long as the object of the present embodiment is not impaired. May be.
Examples of resins other than the polycarbonate resin satisfying the formula (1) include polycarbonate resins such as bisphenol A type or bisphenol Z type, acrylic resins, methacrylic resins, polyarylate resins, polyester resins, polyvinyl chloride resins, polystyrene resins, Acrylonitrile-styrene copolymer resin, acrylonitrile-butadiene copolymer resin, polyvinyl acetate resin, polyvinyl formal resin, polysulfone resin, styrene-butadiene copolymer resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-vinyl acetate -Insulating resins such as maleic anhydride resin, silicone resin, phenol-formaldehyde resin, polyacrylamide resin, polyamide resin, chlorine rubber, and polyvinylcarbazo Le, polyvinyl anthracene, organic photoconductive polymers such as polyvinyl pyrene, and the like.
As content in the case of making resin other than polycarbonate resin which satisfy | fills said Formula (1) in the charge transport layer 6 with respect to the whole charge transport layer 6, the range of 50 mass% or less is mentioned, for example.

(Charge transport material)
As the charge transport material, generally, for example, oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline , 1- [pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, pyrazoline derivatives such as triphenylamine, N, N′-bis (3,4-dimethyl) Aromatic tertiary amino compounds such as phenyl) biphenyl-4-amine, tri (p-methylphenyl) aminyl-4-amine, dibenzylaniline, N, N′-bis (3-methylphenyl) -N, N Aromatic tertiary diamino compounds such as' -diphenylbenzidine, 3- (4'-dimethylaminophenyl) -5,6-di- (4'-methoxyphenyl)- 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, 6-hydroxy Benzofuran derivatives such as -2,3-di (p-methoxyphenyl) benzofuran, α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N-diphenylaniline, enamine derivatives, N-ethylcarbazole, etc. Carbazole derivatives, hole transport materials such as poly-N-vinylcarbazole and its derivatives, quinone compounds such as chloranil and broanthraquinone, tetraanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2, 4,5,7-tetranitro-9-fluorenone, etc. Examples thereof include an electron transport material such as a fluorenone compound, a xanthone compound, and a thiophene compound, and a polymer having a group composed of the above-described compound in a main chain or a side chain.

In the present embodiment, as described above, at least two or more kinds of charge transport materials are used as the charge transport material, and a butadiene compound is used as at least one of the two or more kinds of charge transport materials.
As said butadiene compound, the compound represented by the following general formula (5) or the compound represented by the following general formula (6) is mentioned, for example.
In addition, as a charge transport material, 2 or more types of butadiene compounds may be used, and other charge transport materials other than a butadiene compound and a butadiene compound may be used together. In this case, the mass ratio between the butadiene compound and the other charge transporting material includes, for example, a range of 1: 5 to 5: 1. That is, when using a butadiene compound in combination with another charge transporting material, the content of the butadiene compound in the entire charge transporting material is, for example, in the range of 17% by mass to 83% by mass.

In the general formula (5), R ₇ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , and R ₁₃ may be the same or different, and each independently represents a hydrogen atom, A lower alkyl group (that is, an alkyl group having 1 to 20 carbon atoms), an alkoxy group (for example, an alkoxy group having 1 to 20 carbon atoms), a halogen atom, or a substituted or unsubstituted aryl group. n represents 0 or 1. Examples of the substituent for substituting the aryl group include a halogen atom, an alkoxy group, an alkyl group, and an aryl group.

In the general formula (6), R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ , R ₁₈ , and R ₁₉ may be the same or different from each other, and may be a hydrogen atom, a lower alkyl group (that is, a carbon number). An alkyl group having 1 to 20 carbon atoms), an alkoxy group (for example, an alkoxy group having 1 to 20 carbon atoms), a halogen atom, or a substituted or unsubstituted aryl group. Examples of the substituent for substituting the aryl group in which m and n are 0 or 1 include a halogen atom, an alkoxy group, an alkyl group, and an aryl group.

In the general formula (5), R ₇ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , and R ₁₃ are preferably a hydrogen atom, a lower alkyl group, or an alkoxy group, and a hydrogen atom , An alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms is preferable. Further, n in the general formula (5) is preferably 1.
Among the above, R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ , R ₁₈ , and R ₁₉ in the general formula (6) are preferably a hydrogen atom, a lower alkyl group, or an alkoxy group. An alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms is preferable. In the general formula (6), m is preferably 1, and n is preferably 1.

Illustrative compounds 1-1 to 1-32 which are preferred specific examples of the compound represented by the general formula (5) and Illustrative compound 2-1 which is a preferred specific example of the compound represented by the general formula (6) To 2-20 and the like (that is, the substituents represented by R ₇ to R ₁₉ and the numbers represented by m and n) are shown below, but are not limited thereto.
In addition, the said tributadiene compound is a compound which is m = 1 and n = 1 among the compounds represented by General formula (6).

  Examples of the mass ratio of the binder resin and the charge transport material in the charge transport layer include a range of 2: 8 to 8: 2. That is, the content of the charge transport material with respect to the entire charge transport layer 6 is, for example, in the range of 20% by mass to 80% by mass, and may be in the range of 40% by mass to 60% by mass.

(Coating solution for forming the charge transport layer)
The charge transport layer 6 is formed using a coating liquid for forming a charge transport layer in which the above components are added to a solvent.
Examples of the solvent include known organic solvents, for example, aromatic hydrocarbon solvents such as toluene and chlorobenzene, aliphatic alcohol solvents such as methanol, ethanol, n-propanol, iso-propanol, and n-butanol, acetone, and cyclohexanone. , Ketone solvents such as 2-butanone, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, cyclic or linear ether solvents such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether, methyl acetate, Examples thereof include ester solvents such as ethyl acetate and n-butyl acetate. These solvents may be used alone or in combination of two or more. Any solvent can be used as long as it can dissolve the binder resin as a mixed solvent.

(Fluorine particles)
The charge transport layer 6 may include fluorine particles as described above.
Examples of the fluorine particles include fluorine resin particles. Examples of the fluorine resin include tetrafluoroethylene resin, trifluorinated ethylene resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, Examples thereof include ethylene difluoride dichloride resins and copolymers thereof. Among these, tetrafluoroethylene resin and vinylidene fluoride resin are particularly preferable.

Examples of the primary particle size of the fluorine particles include a range of 0.05 μm to 1 μm, and may be a range of 0.1 μm to 0.5 μm.
As content of the fluorine particle in the charge transport layer 6, the range of 2 mass% or more and 15 mass% or less is mentioned, for example.

  Examples of the dispersion method for dispersing the fluorine particles in the coating liquid for forming the charge transport layer include, for example, a media disperser such as a ball mill, a vibration ball mill, an attritor, a sand mill, an agitator, an ultrasonic disperser, a roll mill, Examples thereof include a method using a medialess disperser such as a high-pressure homogenizer or a nanomizer. Further, 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 the fine liquid is penetrated and dispersed in a high pressure state.

Further, as a dispersion stabilizer for fluorine particles in the coating solution, for example, a fluorine-based surfactant or a fluorine-based graft polymer may be used. Examples of the fluorine-based graft polymer include a macromonomer composed of an acrylic ester compound, a methacrylic ester compound, a styrene compound, and a resin graft-polymerized from perfluoroalkylethyl methacrylate.
Examples of the addition amount of the fluorine-based surfactant and the fluorine-based graft polymer include a mass of 1% to 5% with respect to the mass of the fluorine particles.

  For the purpose of preventing deterioration of the photoreceptor due to ozone, nitrogen oxide, light, or heat generated in the image forming apparatus, an antioxidant, a light stabilizer, a heat stabilizer, etc. are included in each layer constituting the photosensitive layer 3. Additives may be added. For example, examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and their derivatives, organic sulfur compounds, and organic phosphorus compounds. Examples of light stabilizers include derivatives such as benzophenone, benzoazole, dithiocarbamate, and tetramethylpipen.

(Method for forming charge transport layer)
As a method for forming the charge transport layer 6, for example, the charge transport layer forming coating solution is applied on the charge generation layer 5 of the conductive support 2 on which the undercoat layer 4 and the charge generation layer 5 are formed. And a method of forming the charge generation layer 6 by drying.
Examples of the method for applying the coating liquid for forming the charge transport layer on the charge generation layer 5 include dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, and curtain. Examples thereof include a coating method.
And after apply | coating the said coating liquid on the electric charge generation layer 5, the solvent in a coating liquid is removed by a heat drying process. Examples of the film thickness of the charge transport layer 6 include a range of 5 μm to 50 μm, and may be a range of 10 μm to 40 μm.

The photoreceptor 1 of the present embodiment is a function separation type having the charge generation layer 5 and the charge transport layer 6, and the charge transport layer 6 is the outermost surface layer. For example, the charge generation layer and the charge transport layer are combined. A function-integrated type having a single photosensitive layer that also serves as a double layer may be employed. That is, the photoreceptor of this embodiment has a structure in which, for example, an undercoat layer and a single photosensitive layer serving as a charge generation layer and a charge transport layer are laminated in this order on a conductive support. In that case, the photosensitive layer becomes the outermost surface layer. Further, the photoconductor of this embodiment may have a configuration without an undercoat layer.
Further, in the photoreceptor 1 of the present embodiment, the charge transport layer 6 is the outermost surface layer, but a configuration in which a protective layer is further formed on the charge transport layer may be employed. It becomes a surface layer.

  In addition, the method for manufacturing the photoreceptor 1 includes a support preparing step for preparing the conductive support 2, a step for forming the undercoat layer 4, a step for forming the charge generation layer 5, the undercoat layer 4 and the charge. A coating process for coating a coating liquid for forming a charge transport layer on the conductive support 2 on which the generation layer 5 is formed, and a coating liquid coated on the conductive support 2 are dried to form an outermost surface layer. The outermost surface layer forming step is not particularly limited as long as the supporting surface preparing step, the coating step, and the outermost surface layer forming step are included.

  Next, an image forming apparatus and a process cartridge provided with the electrophotographic photosensitive member according to this embodiment will be described.

<Image forming apparatus>
-First embodiment-
FIG. 2 schematically shows the basic configuration of the image forming apparatus according to the first embodiment. The image forming apparatus shown in FIG. 2 is a direct transfer system in which a toner image formed on the surface of a photoreceptor is directly transferred to a transfer medium and no intermediate transfer member or the like is used. The image forming apparatus shown in FIG. 2 is a contact charging method in which only a DC voltage is applied.

  An image forming apparatus 200 shown in FIG. 2 includes, for example, the electrophotographic photosensitive member 1 of the above embodiment, a contact charging type charging device 208 (charging means) that is connected to the power source 209 and charges the electrophotographic photosensitive member 1. An exposure device 210 (electrostatic latent image forming means) for exposing the electrophotographic photosensitive member 1 charged by the charging device 208 to form an electrostatic latent image, and an electrostatic latent image formed by the exposure device 210, A developing device 211 (developing unit) that forms a toner image by developing with a developer containing toner, and a transfer unit 212 (transfer unit) that transfers the toner image formed on the surface of the electrophotographic photosensitive member 1 to the transfer medium 500. ), A toner removing device 213 (toner removing means) for removing the toner remaining on the surface of the electrophotographic photosensitive member 1 after the transfer, and a static eliminator 214 (static eliminating means) for removing the residual potential of the electrophotographic photosensitive member 1. , Covered Comprising a toner image transferred onto the copy medium 500 and the fixing device 215 to fix to the transfer medium 500 (fixing means), a. For example, the static eliminator 214 is not necessarily provided.

The charging device 208 has a charging member, and a voltage is applied to the charging member when the photosensitive member 1 is charged. The voltage range may be positive or negative 50 V to 2000 V, and may be 100 V to 1500 V, depending on the required photoreceptor charge potential when a DC voltage is applied.
In this embodiment, only the DC voltage is applied. However, when the AC voltage is superimposed, the peak-to-peak voltage is, for example, 400V to 1800V, preferably 800V to 1600V, and more preferably 1200V. Above 1600V or less is mentioned. The frequency of the AC voltage is, for example, 50 Hz to 20000 Hz, and preferably 100 Hz to 5000 Hz.

Examples of the charging member include a roller, a brush, and a film. Among them, as the roller-shaped charging member (hereinafter sometimes referred to as “charging roller”), for example, a member composed of a material whose electric resistance is adjusted to a range of 10 ³ Ω to 10 ⁸ Ω can be mentioned. . The charging roller may be a single layer or may be composed of a plurality of layers.
When a charging roller is used as the charging member, examples of the pressure that contacts the photoreceptor 1 include a range of 250 mgf to 600 mgf.

Examples of the material constituting the charging member include synthetic rubber such as urethane rubber, silicon rubber, fluorine rubber, chloroprene rubber, butadiene rubber, EPDM (ethylene-propylene-diene copolymer rubber), epichlorohydrin rubber, polyolefin, polystyrene, chloride, and the like. Examples thereof include an elastomer composed of vinyl or the like as a main material and a suitable amount of a conductivity imparting agent such as conductive carbon, metal oxide, or ionic conductive agent.
Furthermore, a resin such as nylon, polyester, polystyrene, polyurethane, silicone is made into a paint, and an appropriate amount of a conductivity imparting agent such as conductive carbon, metal oxide, and ionic conductive agent is blended therein, and the resulting paint is dipped, sprayed, You may use it, laminating | stacking by methods, such as roll coating.

  When a charging roll is used as the charging member, the charging roll is brought into contact with the surface of the photoreceptor 1 so that the charging means is driven and rotated even if the charging means does not have a driving means. A means may be attached and rotated at a peripheral speed different from that of the photoreceptor 1.

As the exposure apparatus 210, known exposure means is used. Specifically, for example, an optical system device that performs exposure with a light source such as a semiconductor laser, an LED (Light Emitting Diode), or a liquid crystal shutter is used. The amount of time writing, for example, range from 0.5 mJ / ^{m 2} or more 5.0mJ / ^{m 2} and the like on the photosensitive member surface.

As the developing device 211, for example, a two-component developing type developing means for developing a developing brush (developer holding body) to which a developer composed of a carrier and toner adheres is brought into contact with the electrostatic latent image holding body, conductive rubber. Examples include a contact-type one-component developing unit that attaches toner onto an elastic-conveying roll (developer holder) and develops the toner on the electrostatic latent image holder.
The toner is not particularly limited as long as it is a known toner. Specifically, for example, it may be a toner containing at least a binder resin and, if necessary, a colorant, a release agent, etc., or a toner to which an abrasive made of inorganic particles is added. May be. Specific examples of the abrasive used for the toner are as described above.
The method for producing the toner is not particularly limited. For example, a known pulverization method, a wet melt spheronization method prepared in a dispersion medium, suspension polymerization, dispersion polymerization, emulsion polymerization aggregation method and the like are known. Examples thereof include a toner production method using a polymerization method.
When the developer is a two-component developer composed of a toner and a carrier, the carrier is not particularly limited. For example, a core material such as a magnetic metal such as iron oxide, nickel or cobalt, or a magnetic oxide such as ferrite or magnetite. And a carrier coated with a resin layer on the surface of the core material (non-coated carrier). In the two-component developer, for example, the mixing ratio (mass ratio) of the toner and the carrier is in the range of toner: carrier = 1: 100 to 30: 100, and even in the range of 3: 100 to 20: 100. Good.

  Examples of the transfer device 212 include a roller-type contact charging member, a contact transfer charger using a belt, a film, a rubber blade, or the like, or a scorotron transfer charger or a corotron transfer charger using corona discharge. Can be mentioned.

The toner removing device 213 is for removing residual toner adhering to the surface of the electrophotographic photosensitive member 1 after the transfer process, and the electrophotographic photosensitive member 1 thus cleaned is repeatedly subjected to the above image forming process. Provided. As the toner removing device 213, a foreign matter removing member (cleaning blade), brush cleaning, roll cleaning, and the like are used. Among these, it is desirable to use a cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber.
Note that the toner removing device 213 need not be provided when residual toner is not a problem, for example, when the toner hardly remains on the surface of the photoreceptor 1.

  The static eliminator 214 is intended to prevent the residual potential from being brought into the next cycle by neutralizing the residual potential of the photoreceptor 1. For example, when the residual potential is not a problem, such as when using a photoconductor that hardly generates the residual potential, the static eliminator 214 may not be provided.

Examples of the transfer medium 500 include plain paper, recycled paper, and an OHP sheet. Examples of the medium 500 to be transferred include coated paper using calcium carbonate as a white pigment.
As content of the calcium carbonate with respect to the whole coated paper, 1 mass% or more and 25 mass% or less are mentioned, for example, 5 mass% or more and 20 mass% or less may be sufficient.

A basic image forming process of the image forming apparatus 200 will be described.
First, the charging device 208 charges the surface of the photoreceptor 1 to a predetermined potential. Next, the surface of the charged photoreceptor 1 is exposed by the exposure device 210 based on the image signal to form an electrostatic latent image.

Next, the developer is held on the developer holding member of the developing device 211, the held developer is conveyed to the photosensitive member 1, and the developer holding member and the photosensitive member 1 are in proximity (or contact). It is supplied to the electrostatic latent image. As a result, the electrostatic latent image is visualized and becomes a toner image.
The developed toner image is conveyed to the position of the transfer device 212 and transferred directly to the transfer medium 500 by the transfer device 212.

  Next, the transfer medium 500 to which the toner image is transferred is conveyed to the fixing device 215, and the toner image is fixed to the transfer medium 500 by the fixing device 215. Examples of the fixing temperature include 100 ° C. or higher and 180 ° C. or lower.

On the other hand, after the toner image is transferred to the transfer medium 500, the toner particles that are not transferred and remain on the photoreceptor 1 are transported to the contact position with the toner removing device 213 and collected by the toner removing device 213.
Then, after the residual toner is collected, the residual potential remaining on the photoreceptor 1 is neutralized by the static eliminator 214.
As described above, image formation by the image forming apparatus 200 is performed.

-Second Embodiment-
FIG. 3 schematically shows the basic configuration of the image forming apparatus according to the second embodiment. An image forming apparatus 220 shown in FIG. 3 is an intermediate transfer type image forming apparatus. In the housing 400, four electrophotographic photosensitive members 1a, 1b, 1c, and 1d are arranged in parallel along the intermediate transfer belt 409. ing. For example, an image is formed in which the photoreceptor 1a is yellow, the photoreceptor 1b is magenta, the photoreceptor 1c is cyan, and the photoreceptor 1d is black.

Here, the electrophotographic photoreceptors 1a, 1b, 1c, and 1d mounted on the image forming apparatus 220 are the electrophotographic photoreceptors of this embodiment, respectively.
Each of the electrophotographic photoreceptors 1a, 1b, 1c, and 1d rotates in one direction (counterclockwise on the paper surface), and charging rolls 402a, 402b, 402c, and 402d, and developing devices 404a, 404b, and 404c along the rotation direction. 404d, primary transfer rolls 410a, 410b, 410c, 410d and cleaning blades 415a, 415b, 415c, 415d. The developing devices 404a, 404b, 404c, and 404d supply toners of four colors, black, yellow, magenta, and cyan, stored in toner cartridges 405a, 405b, 405c, and 405d, respectively, and primary transfer rolls 410a, 410b, 410c and 410d are in contact with the electrophotographic photoreceptors 1a, 1b, 1c and 1d through the intermediate transfer belt 409, respectively.

  Further, a laser light source (exposure device) 403 is disposed in the housing 400, and irradiates the surfaces of the electrophotographic photoreceptors 1a, 1b, 1c, and 1d after charging with laser light emitted from the laser light source 403. As a result, in the rotation process of the electrophotographic photoreceptors 1a, 1b, 1c, and 1d, the charging, exposure, development, primary transfer, and cleaning (removal of foreign matters such as toner) are sequentially performed, and the toner images of the respective colors are intermediate. The image is transferred onto the transfer belt 409 in an overlapping manner. The intermediate transfer belt 409 is supported with tension by a drive roll 406, a back roll 408, and a support roll 407, and rotates without causing deflection due to the rotation of these rolls. Further, the secondary transfer roll 413 is disposed so as to be in contact with the back roll 408 through the intermediate transfer belt 409. The intermediate transfer belt 409 that has passed through the position sandwiched between the back roll 408 and the secondary transfer roll 413 is cleaned by, for example, a cleaning blade 416 disposed facing the drive roll 406, and then forms the next image. Used repeatedly in the process.

  In addition, a container 411 that houses a transfer medium is provided in the housing 400, and the transfer medium 500 such as paper in the container 411 is sandwiched between the intermediate transfer belt 409 and the secondary transfer roll 413 by the transfer roll 412. Then, the sheet is sequentially transferred to a position sandwiched between two fixing rolls 414 that are in contact with each other, and then discharged to the outside of the housing 400.

  In the above description, the case where the intermediate transfer belt 409 is used as the intermediate transfer member has been described. However, the intermediate transfer member may have a belt shape like the intermediate transfer belt 409 or a drum shape. May be. In the case of a belt shape, a known resin is used as the resin material constituting the base material of the intermediate transfer member. For example, polyimide resin, polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene terephthalate (PAT), ethylenetetrafluoroethylene copolymer (ETFE) / PC, ETFE / PAT, PC / PAT blend material, polyester Resin materials such as polyether ether ketone and polyamide, and resin materials using these as main raw materials. Further, a resin material and an elastic material may be blended and used.

The transfer medium according to the above embodiment is not particularly limited as long as it is a medium that transfers a toner image formed on an electrophotographic photosensitive member.
In the above-described embodiment, the charging roll is used as the charging unit. However, the charging roll is not limited thereto, and a non-contact charging unit such as a corona discharge method such as a scorotron may be used.

<Process cartridge>
FIG. 4 schematically shows a basic configuration of an example of a process cartridge including the electrophotographic photosensitive member of the present embodiment. The process cartridge 300 includes, together with the electrophotographic photoreceptor 1, a contact charging type charging device 208 that charges the electrophotographic photoreceptor 1, and developing an electrostatic latent image formed on the electrophotographic photoreceptor 1 by exposure with toner. A developing device 211 that forms a toner image by developing with an agent; a toner removing device 213 that removes toner remaining on the surface of the electrophotographic photosensitive member 1 after transfer; an opening 218 for exposure; Are combined and integrated using the mounting rail 216.

  The process cartridge 300 includes a transfer device 212 that transfers the toner image formed on the surface of the electrophotographic photosensitive member 1 to the transfer medium 500, and the toner image transferred to the transfer medium 500 to the transfer medium 500. The image forming apparatus main body is composed of a fixing device 215 to be fixed and other components not shown, and constitutes the image forming apparatus together with the image forming apparatus main body.

EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example and a comparative example, this invention is not limited to a following example.
[Example A]
<Example 1>
-Formation of undercoat layer-
100 parts by mass of zinc oxide particles (manufactured by Teika Co., Ltd., average particle size: 70 nm, specific surface area value: 15 m ² / g) are mixed with 500 parts by mass of methanol, and KBM603 (manufactured by Shin-Etsu Chemical Co., Ltd.) 1 is used as a silane coupling agent. .25 parts by mass was added and stirred for 2 hours. Thereafter, methanol was removed by distillation under reduced pressure, baking was performed at 120 ° C. for 3 hours, and zinc oxide particles surface-treated with a silane coupling agent were obtained.

  60 parts by mass of zinc oxide particles surface-treated with the silane coupling agent, 0.6 parts by mass of alizarin, 13.5 parts by mass of blocked isocyanate (Sumid 3173, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent, , 15 parts by mass of butyral resin (ESLEC BM-1, manufactured by Sekisui Chemical Co., Ltd.), 38 parts by mass of a solution obtained by dissolving 85 parts by mass of methyl ethyl ketone, and 25 parts by mass of methyl ethyl ketone are mixed, and glass beads having a diameter of 1 mm are used. Dispersion was performed for 4 hours in a sand mill to obtain a dispersion. To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added as a catalyst, and a coating solution for forming an undercoat layer. Got. This coating solution was applied on an aluminum substrate having a diameter of 30 mm by a dip coating method, followed by drying and curing at 180 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.

-Formation of charge generation layer-
Next, as a charge generation material, it has strong diffraction peaks at Bragg angles (2θ ± 0.2 °) with respect to CuKα characteristic X-rays of at least 7.4 °, 16.6 °, 25.5 ° and 28.3 °. Using a glass bead having a diameter of 1 mm, a mixture of 15 parts by mass of chlorogallium phthalocyanine crystal, 10 parts by mass of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nippon Union Carbide) and 300 parts by mass of n-butyl alcohol was used. Then, it was dispersed in a sand mill for 4 hours to obtain a coating solution for the charge generation layer. This coating solution for forming a charge generation layer was dip-coated on the undercoat layer and dried to obtain a charge generation layer having a thickness of 0.2 μm.

-Formation of charge transport layer-
Next, 0.6 parts by mass of tetrafluoroethylene resin particles (average particle size: 0.2 μm) and 0.015 parts by mass of a fluorinated alkyl group-containing methacrylic copolymer (weight average molecular weight: 30000), 4 parts by mass of tetrahydrofuran, The mixture was kept at a liquid temperature of 20 ° C. together with 1 part by mass of toluene and stirred for 48 hours to obtain a tetrafluoroethylene resin particle suspension.

Next, as a binder resin, a polycarbonate polymer comprising a repeating unit represented by the following structural formula (7) and a repeating unit represented by the following structural formula (8) (viscosity average molecular weight: 58,000, weight average molecular weight: 128,000, Mv / Mw: 0.45) 6 parts by mass, 3 parts by mass of the following compound (A) as a charge transport material, and exemplified compounds shown as specific examples of the compound represented by the general formula (6) 1-11 parts by mass of 2-11 and 0.1 part by mass of 2,6-di-t-butyl-4-methylphenol as an antioxidant were mixed, and 31 parts by mass of tetrahydrofuran and 4 parts by mass of toluene were mixed. To obtain a solution.
The content of the repeating unit represented by the following structural formula (7) is 15 mol% with respect to the entire repeating unit constituting the polycarbonate polymer, and the repeating unit represented by the following structural formula (8) The content was 85 mol%.

A high-pressure homogenizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.) equipped with a penetrating chamber having a fine channel was added to the suspension obtained by adding the tetrafluoroethylene resin particle suspension to the obtained solution and stirring and mixing. Fluorine-modified silicone oil (trade name: FL-100 manufactured by Shin-Etsu Silicone Co., Ltd.) was added to a solution obtained by repeating the dispersion treatment by increasing the pressure up to 500 kgf / cm ² 6 times and stirring. A coating solution for forming a charge transport layer was obtained.
This coating solution was applied onto the charge generation layer and dried at 135 ° C. for 30 minutes to form a charge transport layer having a thickness of 25 μm. Thus, an electrophotographic photoreceptor of Example 1 was obtained.

<Example 2>
In the coating liquid for forming a charge transport layer of Example 1, the binder resin is a polycarbonate polymer (viscosity comprising a repeating unit represented by the following structural formula (9) and a repeating unit represented by the following structural formula (10). A coating solution for forming a charge transport layer was prepared in the same manner as in Example 1 except that the average molecular weight was 45,000, the weight average molecular weight was 89,000, and Mv / Mw was 0.51). In the same manner as in Example 1, a charge transport layer having a thickness of 25 μm was formed on the charge generation layer, whereby an electrophotographic photoreceptor of Example 2 was obtained.
The content of the repeating unit represented by the following structural formula (9) is 25 mol% with respect to the entire repeating unit constituting the polycarbonate polymer, and the repeating unit represented by the following structural formula (10) The content was 75 mol%.

<Example 3>
In the coating liquid for forming a charge transport layer of Example 1, the binder resin is a polycarbonate polymer (viscosity comprising a repeating unit represented by the following structural formula (11) and a repeating unit represented by the following structural formula (12). The charge transport layer forming coating solution was prepared in the same manner as in Example 1 except that the average molecular weight was 41200, the weight average molecular weight was 76400, and Mv / Mw was 0.54). In the same manner as described above, a charge transport layer having a thickness of 25 μm was formed on the charge generation layer, whereby an electrophotographic photoreceptor of Example 3 was obtained.
The content of the repeating unit represented by the following structural formula (11) is 30 mol% with respect to the entire repeating unit constituting the polycarbonate polymer, and the repeating unit represented by the following structural formula (12) The content was 70 mol%.

<Example 4>
In the coating liquid for forming a charge transport layer of Example 1, the binder resin is a polycarbonate polymer (viscosity comprising a repeating unit represented by the following structural formula (13) and a repeating unit represented by the following structural formula (14). The charge transport layer forming coating solution was prepared in the same manner as in Example 1 except that the average molecular weight was 62500, the weight average molecular weight was 140000, and Mv / Mw was 0.45). In the same manner as described above, a charge transport layer having a thickness of 25 μm was formed on the charge generation layer, whereby an electrophotographic photosensitive member of Example 4 was obtained.
The content of the repeating unit represented by the following structural formula (13) is 30 mol% with respect to the entire repeating unit constituting the polycarbonate polymer, and the repeating unit represented by the following structural formula (14) The content was 70 mol%.

<Example 5>
In the coating liquid for forming a charge transport layer of Example 1, 3 to 10 parts by mass of the compound (A) as a charge transport material and exemplified compound 1-17 shown as specific examples of the compound represented by the general formula (5) The charge transport layer forming coating solution was prepared in the same manner as in Example 1 except that 1 part by weight of the charge transport layer was used. Using this solution, a charge transport layer having a thickness of 25 μm was formed on the charge generation layer in the same manner as in Example 1. And an electrophotographic photosensitive member of Example 5 was obtained.

<Comparative Example 1>
In the charge transport layer forming coating solution of Example 1, a charge transport layer forming coating solution was prepared in the same manner as in Example 1 except that 4 parts by mass of the compound (A) was used as the charge transport material. Using this, a charge transport layer having a thickness of 25 μm was formed on the charge generation layer in the same manner as in Example 1, and an electrophotographic photoreceptor of Comparative Example 1 was obtained.

<Comparative example 2>
In the coating liquid for forming a charge transport layer of Example 1, except that 4 parts by mass of the exemplified compound 1-17 shown in the specific example of the compound represented by the general formula (5) was used as the charge transport material. A charge transport layer forming coating solution was prepared in the same manner as in Example 1, and a charge transport layer having a thickness of 25 μm was formed on the charge generation layer in the same manner as in Example 1. A photoreceptor was obtained.

<Comparative Example 3>
In the coating liquid for forming a charge transport layer of Example 1, the binder resin was a polycarbonate polymer composed of a repeating unit represented by the following structural formula (15) (viscosity average molecular weight: 60,000, weight average molecular weight: 147, 000, Mv / Mw: 0.41) except that the coating liquid for forming the charge transport layer was prepared in the same manner as in Example 1, and this was used on the charge generation layer in the same manner as in Example 1. A charge transport layer having a thickness of 25 μm was formed to obtain an electrophotographic photoreceptor of Comparative Example 3.

<Comparative example 4>
In the coating liquid for forming a charge transport layer of Example 1, the binder resin is a polycarbonate polymer (viscosity comprising a repeating unit represented by the following structural formula (16) and a repeating unit represented by the following structural formula (17). A coating solution for forming a charge transport layer was prepared in the same manner as in Example 1 except that the average molecular weight was 73,000, the weight average molecular weight was 190,500, and Mv / Mw was 0.38). In the same manner as in Example 1, a charge transport layer having a thickness of 25 μm was formed on the charge generation layer, whereby an electrophotographic photoreceptor of Comparative Example 4 was obtained.
The content of the repeating unit represented by the following structural formula (16) is 50 mol% with respect to the entire repeating unit constituting the polycarbonate polymer, and the repeating unit represented by the following structural formula (17) The content was 50 mol%.

<Comparative Example 5>
In the coating liquid for forming a charge transport layer of Example 1, Example 1 was used except that 2 parts by mass of the compound (A) and 2 parts by mass of the following compound (B) were used as the charge transport material. Similarly, a coating solution for forming a charge transport layer was prepared, and a charge transport layer having a thickness of 25 μm was formed on the charge generation layer in the same manner as in Example 1, and the electrophotographic photoreceptor of Comparative Example 5 was prepared. Obtained.

<Evaluation of photoreceptor>
-Durability evaluation of photoreceptor surface (wear amount evaluation and image evaluation)-
The electrophotographic photosensitive members of Examples and Comparative Examples are mounted on Docprint A505 manufactured by Fuji Xerox, and 20,000 sheets of image formation tests are performed in an environment of low temperature and low humidity (10 ° C., 20% RH). An image formation test of 20,000 sheets was performed in an environment (28 ° C., 75% RH). The transfer medium used in the image formation test is a monochrome copy / printer paper (Fuji Xerox Co., Ltd., model number: P), and the content of calcium carbonate in the entire paper is 9% by mass.
Thereafter, 50% halftone (black) image formation was performed, and the obtained image was evaluated by the following index, and image evaluation was performed. The results are shown in Table 3.
Further, after removing the electrophotographic photosensitive member after the image forming test, measuring the film thickness of the electrophotographic photosensitive member using an eddy current film thickness meter, and measuring the change in film thickness before and after the image forming test, The amount of wear on the photoreceptor surface was measured. The results are shown in Table 3.

-Evaluation index for image evaluation-
A: Good (no reduction in image density, uneven image density, and no image quality defect)
B: Image density slightly decreases C: Image density unevenness occurs D: Image quality defect occurs E: Image density unevenness and image defect occur

-Durability evaluation of photoreceptor surface using different paper (Abrasion amount evaluation)-
The image formation test was performed in the same manner as the image formation test except that the electrophotographic photosensitive members of Example 1, Example 3, Comparative Example 1 and Comparative Example 3 were mounted on DocuCenterColor 1250 manufactured by Fuji Xerox and the paper used was changed. Then, the amount of wear on the surface of the photoreceptor was evaluated in the same manner as described above. The results are shown in Table 4.
Note that the transfer medium used in the image formation test is copy / printer paper (paper 2, manufactured by Xerox Corporation, model number: Xerox Business Multipurpose Copy Paper 4200, calcium carbonate 17% by mass), and color copy / printer paper double-sided coat type (paper 3, Fuji Xerox Co., Ltd., model number: JD COAT157, calcium carbonate 20% by mass).

[Example B]
<Example B1>
A charge transport layer forming coating solution was prepared in the same manner as in Example 1 except that the tetrafluoroethylene resin particle suspension was not used in the charge transport layer forming coating solution of Example 1. In the same manner as in Example 1, a charge transport layer having a thickness of 25 μm was formed on the charge generation layer to obtain an electrophotographic photoreceptor of Example B1.

<Example B3>
In the charge transport layer forming coating solution of Example 3, a charge transport layer forming coating solution was prepared in the same manner as in Example 3 except that the tetrafluoroethylene resin particle suspension was not used. In the same manner as in Example 3, a charge transport layer having a thickness of 25 μm was formed on the charge generation layer to obtain an electrophotographic photoreceptor of Example B3.

<Comparative Example B1>
In the charge transport layer forming coating solution of Comparative Example 1, a charge transport layer forming coating solution was prepared in the same manner as in Comparative Example 1 except that the tetrafluoroethylene resin particle suspension was not used. In the same manner as in Comparative Example 1, a charge transport layer having a thickness of 25 μm was formed on the charge generation layer to obtain an electrophotographic photoreceptor of Comparative Example B1.

<Comparative Example B3>
In the charge transport layer forming coating solution of Comparative Example 3, a charge transport layer forming coating solution was prepared in the same manner as in Comparative Example 3 except that the tetrafluoroethylene resin particle suspension was not used. In the same manner as in Comparative Example 3, a charge transport layer having a thickness of 25 μm was formed on the charge generation layer to obtain an electrophotographic photosensitive member of Comparative Example B3.

<Evaluation of photoreceptor>
-Durability evaluation of photoconductor surface (wear amount evaluation)-
In the same manner as in Example A, the amount of wear on the photoreceptor surface was measured. The results are shown in Table 5.

  From the above evaluation results, it was confirmed that the electrophotographic photoreceptors of the examples had less wear compared to the electrophotographic photoreceptors of the comparative examples, and the image quality of images formed after long-term use was good. In particular, it was confirmed that the electrophotographic photoconductors of the examples had less wear than the electrophotographic photoconductors of the comparative examples even when an image formation test was performed using paper containing a large amount of calcium carbonate.

  As mentioned above, although embodiment and the Example were described, it is not limited to these. For example, the electrophotographic photosensitive member according to this embodiment is not limited to the image forming apparatus illustrated in FIGS. 2 to 4, and employs an image forming method such as an electrophotographic method to form a color or monochrome image. Used in image forming apparatuses such as printers, printers and facsimiles.

1, 1a, 1b, 1c, 1d Electrophotographic photosensitive member, 2 support, 3 photosensitive layer, 4 undercoat layer, 5 charge generation layer, 6 charge transport layer, 200 image forming apparatus, 208 charging apparatus, 210 exposure apparatus, 211 Developing Device, 212 Transfer Device, 213 Toner Removal Device, 214 Charger, 215 Fixing Device, 220 Image Forming Device, 300 Process Cartridge, 404a, 404b, 404c, 404d Developing Device, 500 Transferred Medium

Claims (5)

A support;
One or more layers provided on the support and including at least a photosensitive layer;
With
Of the one or more layers, the outermost surface layer disposed on the side farthest from the support is two or more kinds of charge transports including at least a polycarbonate resin satisfying the following formula (1) and a compound having a butadiene structure. And an electrophotographic photoreceptor containing the material.
Formula (1): 0.45 ≦ (Mv / Mw) ≦ 0.55
[In the above formula (1), Mv represents the viscosity average molecular weight, and Mw represents the weight average molecular weight. ]   The electrophotographic photoreceptor according to claim 1, wherein the compound having a butadiene structure is a compound having three butadiene structures in one molecule. The electrophotographic photosensitive member according to claim 1 or 2,
A charging means for charging the surface of the electrophotographic photosensitive member, a developing means for developing a latent electrostatic image formed on the electrophotographic photosensitive member with a developer to form a toner image, and a surface of the electrophotographic photosensitive member. At least one selected from the group consisting of toner removing means for removing residual toner;
A process cartridge comprising: 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 exposing the surface of the charged electrophotographic photosensitive member to form an electrostatic latent image;
Developing means for developing the electrostatic latent image with a developer to form a toner image;
Transfer means for transferring the toner image to a transfer medium;
An image forming apparatus. A charging step for charging the surface of the electrophotographic photosensitive member according to claim 1 or 2,
An electrostatic latent image forming step of forming an electrostatic latent image by exposing the surface of the charged electrophotographic photosensitive member;
A developing step of developing the electrostatic latent image with a developer to form a toner image;
A transfer step of transferring the toner image to a transfer medium;
An image forming method comprising: