JP2011027807A - Electrophotographic photoreceptor, image forming apparatus, and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor in which a desired amount of wear is obtained in the initial stage and wear resistance in long-term use is improved. <P>SOLUTION: The electrophotographic photoreceptor includes a conductive substrate and a photosensitive layer containing fluorocarbon resin particles and metal oxide particles and having an outermost surface layer satisfying expressions (1):0.05 (μm/single reciprocation)≤Sa≤0.2 (μm/single reciprocation) and (2):Sb/Sa≤0.5. wherein Sa represents a wear amount per a single reciprocation in a region at a depth of less than 4 μm from the surface, and Sb represents a wear amount per a single reciprocation in a region at a depth of 4 μm or more and 10 μm or less, in a test of repeatedly reciprocally moving a sapphire needle having 0.1 mm radius of curvature of the tip at a velocity of 5 mm/s while pressing the needle to the outermost surface layer under 50 g load until the layer is worn to a depth of 10 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  Electrophotographic image formation is widely used in fields such as copying machines and laser beam printers. In an electrophotographic photoreceptor used in an electrophotographic image forming apparatus, various methods have been studied in order to improve the durability of the photosensitive layer.

  For example, there is a method of laminating a protective layer on the surface of the photosensitive layer, pH buffering agent (alkali metal salt of organic acid, alkaline earth metal salt, etc.) and wear-resistant particles (fluorine resin, silicone resin, metal oxide, etc.) ) Has been proposed (see, for example, Patent Document 1).

On the other hand, a method of dispersing particles in the charge transport layer of the outermost surface layer has also been taken, and a method of dispersing fluororesin particles in the charge transport layer of the outermost surface layer has been proposed.
Also, a method of adding inorganic particles to the outermost surface layer of the photoreceptor (see, for example, Patent Document 2), or adding inorganic particles having a volume average particle diameter of 0.05 μm or more and 1.5 μm or less to the outermost surface layer of the photoreceptor. A method (for example, see Patent Document 3) has been proposed.

JP 2001-305761 A JP-A-5-158250 Japanese Patent No. 3859086

  The present invention provides an electrophotographic photoreceptor having a desired amount of initial wear and improved wear resistance over time as compared to the case where at least one of the formulas (1) and (2) is not satisfied. With the goal.

The above object is achieved by the present invention described below.
That is, the invention according to claim 1
A conductive substrate;
A photosensitive layer comprising an outermost surface layer containing fluororesin particles and metal oxide particles and satisfying the following formulas (1) and (2):
An electrophotographic photosensitive member having
Formula (1) 0.05 (μm / 1 reciprocation) ≦ Sa ≦ 0.2 (μm / 1 reciprocation)
Formula (2) Sb / Sa ≦ 0.5
(In the above formula (1) and formula (2), Sa repeatedly reciprocates at a speed of 5 mm / s while pressing a sapphire needle having a radius of curvature of 0.1 mm at the tip of the outermost surface layer with a load of 50 g. In the test for rubbing to a depth of 10 μm, the amount of wear per reciprocation in the region below the depth of 4 μm from the surface is represented, and Sb represents the amount of wear per reciprocation in the region of the depth of 4 μm to 10 μm from the surface in the test. To express.)

The invention according to claim 2
When the sapphire needle having a radius of curvature of 0.1 mm at the tip is pressed against the outermost surface layer with a load of 50 g, the total wear amount is less than 6 μm when it is rubbed by reciprocating 200 times at a speed of 5 mm / s. The electrophotographic photosensitive member according to claim 1.

The invention according to claim 3
The electrophotographic photoreceptor according to claim 1 or 2,
A charging device for charging the electrophotographic photosensitive member;
A latent image forming device that exposes the surface of the charged electrophotographic photosensitive member to form an electrostatic latent image; and
A developing device for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member to form a toner image;
A transfer device for transferring the toner image formed on the surface of the electrophotographic photosensitive member to the surface of a recording medium;
A cleaning device for cleaning the surface of the electrophotographic photosensitive member;
An image forming apparatus.

The invention according to claim 4
It is detachable from the image forming apparatus,
The electrophotographic photosensitive member according to claim 1 or 2,
A charging device that charges the electrophotographic photosensitive member, a latent image forming device that exposes the surface of the charged electrophotographic photosensitive member to form an electrostatic latent image, and an electrostatic latent image formed on the surface of the electrophotographic photosensitive member. Developing device for developing image to form toner image, transfer device for transferring toner image formed on surface of electrophotographic photosensitive member to surface of recording medium, and cleaning device for cleaning surface of electrophotographic photosensitive member At least one selected from the group of:
A process cartridge comprising:

  According to the first aspect of the present invention, compared to the case where at least one of the expressions (1) and (2) is not satisfied, a desired amount of initial wear is obtained, and the image flow and density unevenness are affected over time. Abrasion resistance is improved.

  According to the second aspect of the present invention, the abrasion resistance that affects the image flow and density unevenness is higher than that in the case where the total wear amount is 6 μm or more in the friction test using the sapphire needle and reciprocated 200 times. Improves.

  According to the third aspect of the present invention, the life of the apparatus can be extended while suppressing image flow and density unevenness as compared with the case where this configuration is not provided.

  According to the fourth aspect of the present invention, the life of the process cartridge can be extended while suppressing the image flow and density unevenness as compared with the case where the present configuration is not provided.

FIG. 3 is a schematic cross-sectional view showing a layer structure in a preferred example of the photoreceptor according to the present embodiment. 1 is a cross-sectional view schematically showing a basic configuration of a preferred example of an image forming apparatus according to an embodiment. It is sectional drawing which shows schematically the basic composition of the other example of the image forming apparatus which concerns on this embodiment. It is sectional drawing which shows schematically the basic composition of a suitable example of the process cartridge which concerns on this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

<Electrophotographic photoreceptor>
The electrophotographic photoreceptor according to the exemplary embodiment (hereinafter may be simply referred to as “photoreceptor”) includes a conductive substrate, fluororesin particles, and metal oxide particles, and includes the following formulas (1) and ( And a photosensitive layer having an outermost surface layer satisfying 2).
Formula (1) 0.05 (μm / 1 reciprocation) ≦ Sa ≦ 0.2 (μm / 1 reciprocation)
Formula (2) Sb / Sa ≦ 0.5
(In the above formula (1) and formula (2), Sa repeatedly reciprocates at a speed of 5 mm / s while pressing a sapphire needle having a radius of curvature of 0.1 mm at the tip to the outermost surface layer with a load of 50 g. In the test for rubbing to a depth of 10 μm, the amount of wear per reciprocation in the region below the depth of 4 μm from the surface is represented, and Sb represents the amount of wear per reciprocation in the region of the depth of 4 μm to 10 μm from the surface in the test. To express.)

In the photoconductor according to the present embodiment, first, in the region where the depth from the surface of the photoconductor is less than 4 μm, in the test, 0.05 (μm / 1 reciprocation) as shown in the above formula (1). ) Wear within the range of Sa. This means that a desired amount of initial wear (a time when the wear depth is less than 4 μm) on the surface of the photoreceptor is obtained. For example, if the photoconductor according to the present exemplary embodiment is used in an image forming apparatus, even if a discharge product generated by discharge of a charging device or the like adheres to the surface of the photoconductor, the surface of the photoconductor is worn. At the same time, the discharge product is removed. Therefore, image quality defects in the image flow due to the adhesion of the discharge product to the surface of the photoreceptor are suppressed.
Secondly, in the photoconductor according to the present embodiment, in the region where the depth from the surface of the photoconductor is 4 μm or more, Sb / Sa ≦ 0.5 is satisfied in the above test as shown in the above formula (2). The ratio of the wear of the region of 4 μm or more to the region satisfying, that is, the depth of less than 4 μm is controlled to 50% or less. Accordingly, in the region deeper than 4 μm from the surface, the progress of the wear of the photosensitive member is suppressed, and the wear resistance over time (when the wear depth is 4 μm or more) is improved against the mechanical external force. For example, if the photoconductor according to the present embodiment is used in an image forming apparatus, the life of the photoconductor is extended by improving the wear resistance of the photoconductor, and as a result, the life of the apparatus itself is extended. It is done.

  Here, when stress is continuously applied to the photoconductor usually by mechanical friction, transfer of a part of the object to be worn proceeds due to adhesion of the frictional surface and fracture of the adhesion portion. That is, since wear accelerates as the rupture of the object to be worn progresses, in many cases, it becomes an aspect of “Sa <Sb”, and wear further progresses with time. However, if the wear pattern over time (the wear pattern in the region of depth of 4 μm or more) is stable as compared with the initial wear pattern (the wear pattern in the region of depth of less than 4 μm), “ It can take the form of Sb <Sa ”. In particular, by being in the range of “Sb / Sa ≦ 0.5”, long-term stable wear can be obtained, and wear resistance over time can be obtained.

  The reason why the depth separating Sa and Sb is set to “4 μm” is that the influence from the surface of the photosensitive member is sufficiently small.

In the above formula (1), Sa ≦ 0.2 (μm / 1 reciprocation) provides good wear resistance even in the initial stage, while 0.05 (μm / 1 reciprocation) ≦ Sa. A desired amount of wear in the initial stage is obtained, and even when used in an image forming apparatus, image quality defects in the image flow are suppressed. It is more desirable that the above formula (1) further satisfies the following formula (1 ′).
Formula (1 ′) 0.05 (μm / 1 reciprocation) ≦ Sa ≦ 0.15 (μm / 1 reciprocation)

Further, when Sb / Sa ≦ 0.5 in the above formula (2), wear resistance over time can be obtained. It is more desirable that the above formula (2) further satisfies the following formula (2 ′).
Formula (2 ′) Sb / Sa ≦ 0.2

In the photoreceptor according to the present embodiment, when the sapphire needle having a radius of curvature of 0.1 mm at the tip is pressed against the outermost surface layer with a load of 50 g, it is rubbed by reciprocating 200 times repeatedly at a speed of 5 mm / s. The total wear amount (Ss) is preferably less than 6 μm.
When the total wear amount is less than 6 μm, suitable wear resistance can be obtained.

  Incidentally, the “outermost surface layer” constituting the photosensitive layer in the photoreceptor according to the present embodiment may be the outermost surface layer in the photosensitive layer composed of a plurality of layers, or the single layer in the photosensitive layer composed of a single layer. It may be a layer. Examples of the former include, for example, a charge transport layer in a photoreceptor composed of a charge generation layer and a charge transport layer. On the other hand, examples of the latter include a photosensitive layer in which the functions of the charge generation layer and the charge transport layer are integrated. Can be mentioned.

  The photoreceptor according to this embodiment contains fluororesin particles and metal oxide particles as described above. The friction coefficient on the surface of the photoreceptor decreases due to the inclusion of the fluororesin particles, and the mechanical strength (for example, indentation hardness) increases due to the inclusion of the metal oxide particles. By containing each of these particles and controlling the composition (selection of each particle, adjustment of the content, etc.), the range of “Sa” and “Sb / Sa” is adjusted to a desirable range.

-Friction test with sapphire needles-
Here, the measurement method of the “Sa, Sb, Ss” will be described.
First, using a load-fluctuating friction and wear test system (manufactured by Shinto Kagaku Co., Ltd., Tribogear, type: HHS2000), a sapphire needle with a radius of curvature of 0.1 mm at the tip is pressed against the surface of the photoreceptor, and the following measurement is performed. Wear marks were formed by repeatedly reciprocating and rubbing depending on conditions.
・ Measurement mode: Reciprocating measurement mode with acceleration / deceleration ・ Measurement distance: 20mm
・ Measurement speed: 5mm / sec
・ Minimum load: 1g
・ Maximum load: 50g
The "acceleration / deceleration reciprocation measurement mode" here means that the load applied to the measurement sample when reciprocating the set measurement distance is from the set minimum load to the maximum load in the forward path, and in the return path This is a measurement mode that fluctuates from the set maximum load to the minimum load, and means that a certain frictional part during repeated reciprocation is rubbed with the same load from start to finish.
About the wear trace formed by said method, the amount of wear (depth of wear trace) was measured by observing directly using a confocal laser microscope (OLYMPAS company make, OLS1100). The value of the amount of wear is the depth of the portion that is worn at the maximum in the observed image of the wear scar rubbed under a load of 50 g with the surface of the photoconductor as the zero point.
The amount of wear per reciprocation in the region where the worn depth is less than 4 μm from the surface of the photoreceptor is “Sa”, and the amount of wear per reciprocation in the region where the worn depth is 4 μm or more and 10 μm or less from the surface of the photoreceptor. Is “Sb”. Further, the total wear amount when the friction is caused by reciprocating 200 times repeatedly is defined as “Ss”.

  Next, the photoconductor according to this embodiment will be described in detail with reference to the drawings. Hereinafter, as an example of the photoconductor according to the exemplary embodiment, a photoconductor provided with a function-separated type photoconductive layer having a charge generation layer and a charge transport layer will be described.

FIG. 1 is a schematic cross-sectional view showing a layer structure in a preferred example of the photoreceptor according to the present 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 is formed on the surface of a conductive substrate 2. 4. The charge generation layer 5 and the charge transport layer 6 are stacked in this order.
Hereinafter, each element of the photoreceptor 1 will be described.

Conductive substrate As the conductive substrate (hereinafter sometimes referred to simply as “substrate”) 2, any substrate may be used as long as it has been 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 coated with or impregnated with a property-imparting agent, and plastic films. The shape of the substrate 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 substrate 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. May be.

Note that “conductive” in the conductive substrate 2 means that the volume resistivity is in the range of 10 ¹³ Ωcm or less.

Undercoat layer The undercoat layer 4 is provided as necessary for the purpose of preventing light reflection on the surface of the substrate 2 and preventing inflow of unnecessary carriers from the substrate 2 to the photosensitive layer 3. Materials for the undercoat layer 4 include metal powders such as aluminum, copper, nickel, and silver, conductive metal oxides such as antimony oxide, indium oxide, tin oxide, and zinc oxide, carbon fiber, carbon black, and graphite. Examples thereof include a conductive material such as powder dispersed in a binder resin and coated on a support. Two or more kinds of conductive metal oxides may be used in combination. Further, the powder resistance may be controlled by performing a surface treatment with a coupling agent on the conductive metal oxide.

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, and charge transport properties A charge transporting resin having a group or a conductive resin such as polyaniline is used.
The ratio of the conductive metal oxide and the binder resin in the undercoat layer 4 is not particularly limited and can be arbitrarily set.

  When the undercoat layer 4 is formed, a coating solution in which the above components are added to a solvent is used. Examples of such solvents include aromatic hydrocarbon solvents such as toluene and chlorobenzene, aliphatic alcohol solvents such as methanol, ethanol, n-propanol, iso-propanol, and n-butanol, acetone, cyclohexanone, and 2-butanone. Ketone solvents, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform, ethylene chloride, cyclic or linear ether solvents such as tetrahydrofuran, dioxane, ethylene glycol, diethyl ether, methyl acetate, ethyl acetate, n acetate -Organic solvents, such as ester solvents, such as butyl. These solvents are used alone or in combination of two or more. When mixing, any solvent can be used as long as it can dissolve the binder resin as a mixed solvent.

  In addition, as a method for dispersing the conductive metal oxide in the coating liquid for forming the undercoat layer 4, a media dispersing machine such as a ball mill, a vibrating ball mill, an attritor, a sand mill, a horizontal sand mill, stirring, ultrasonic wave Medialess dispersers such as dispersers, roll mills, and high-pressure homogenizers are used. 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.

  As a method of applying the coating liquid for forming the undercoat layer 4 thus obtained on the substrate 2, dip coating method, push-up coating method, wire bar coating method, spray coating method, blade coating method, knife Examples thereof include a coating method and a curtain coating method. 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. Resin particles may be added to the undercoat layer 4 in order to adjust the surface roughness. As the resin particles, silicone resin particles, cross-linked PMMA resin particles, and the like are used.

  Further, the surface of the undercoat layer 4 may be polished for adjusting the surface roughness. As a polishing method, buffing, sandblasting, wet honing, grinding, or the like is used.

Intermediate layer Although not shown, an intermediate layer may be further provided on the undercoat layer 4. 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. An organometallic compound containing These compounds are used alone or as a mixture or polycondensate of a plurality of compounds.

  As the solvent used for forming the intermediate layer, known organic solvents, for example, aromatic hydrocarbon solvents such as toluene and chlorobenzene, aliphatics such as methanol, ethanol, n-propanol, iso-propanol, and n-butanol Alcohol solvents, ketone solvents such as acetone, cyclohexanone and 2-butanone, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, cyclic or linear such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether Examples include ether solvents, ester solvents such as methyl acetate, ethyl acetate, and n-butyl acetate. These solvents are 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.

As a coating method for forming the intermediate layer, a usual method such as a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, or a curtain coating method is used.
When forming the intermediate layer, the film thickness is preferably in the range of 0.1 μm to 3 μm. Further, the intermediate layer in this case 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 suitable binder resin. As such a charge generation material, phthalocyanine pigments such as metal-free phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, dichlorotin phthalocyanine, and titanyl phthalocyanine are used. In particular, a chlorogallium phthalocyanine crystal having strong diffraction peaks at Bragg angles (2θ ± 0.2 °) to CuKα characteristic X-rays of at least 7.4 °, 16.6 °, 25.5 ° and 28.3 °, CuKα Strong diffraction peaks at Bragg angles (2θ ± 0.2 °) of characteristic X-rays of at least 7.7 °, 9.3 °, 16.9 °, 17.5 °, 22.4 ° and 28.8 ° A metal-free phthalocyanine crystal having a Bragg angle (2θ ± 0.2 °) with respect to CuKα characteristic X-ray of at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25. Hydroxygallium phthalocyanine crystals with strong diffraction peaks at 1 ° and 28.3 °, at least 9.6 °, 24.1 ° and 27.2 ° Bragg angles (2θ ± 0.2 °) with respect to CuKα characteristic X-rays strong Titanyl phthalocyanine crystal having a folding peak is used. In addition, quinone pigments, perylene pigments, indigo pigments, bisbenzimidazole pigments, anthrone pigments, quinacridone pigments and the like are also 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 5 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, and acrylonitrile-styrene. Polymer 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 of the charge generation material and the binder resin is preferably in the range of 10: 1 to 1:10.

  When the charge generation layer 5 is formed, a coating solution in which the above components are added to a solvent is used. Examples of such solvents include aromatic hydrocarbon solvents such as toluene and chlorobenzene, aliphatic alcohol solvents such as methanol, ethanol, n-propanol, iso-propanol, and n-butanol, acetone, cyclohexanone, and 2-butanone. Ketone solvents, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform, ethylene chloride, cyclic or linear ether solvents such as tetrahydrofuran, dioxane, ethylene glycol, diethyl ether, methyl acetate, ethyl acetate, n acetate -Organic solvents, such as ester solvents, such as butyl. These solvents are 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.

  In order to disperse the charge generating material in the resin, it is desirable to perform a dispersion treatment on the coating solution. As a dispersion method, a media disperser such as a ball mill, a vibrating ball mill, an attritor, a sand mill, or a horizontal sand mill, or a medialess disperser such as an agitator, an ultrasonic disperser, a roll mill, or a high-pressure homogenizer is used. 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.

  As a method of applying the coating solution thus obtained on the undercoat layer 4 (or on the intermediate layer in the case of having the aforementioned intermediate layer), a dip coating method, a push-up coating method, a wire bar coating method, Examples thereof include a spray coating method, a blade coating method, a knife coating method, and a curtain coating method. The film thickness of the charge generation layer 5 is desirably 0.01 μm or more and 5 μm or less.

Charge transport layer In the photoreceptor 1 shown in FIG. 1, the charge transport layer 6 constitutes the outermost surface layer of the photosensitive layer 3. Therefore, the charge transport layer 6 contains fluororesin particles and metal oxide particles, and satisfies the above formulas (1) and (2).

  The content of the fluororesin particles with respect to the total solid content of the charge transport layer 6 is preferably 1% by mass or more and 15% by mass or less, more preferably 4% by mass or more and 12% by mass or less, and more preferably 6% by mass or more. It is especially preferable that it is 10 mass% or less. When the content of the fluororesin particles with respect to the total solid content of the charge transport layer 6 is 1% by mass or more, the charge transport layer 6 is sufficiently modified by the dispersion of the fluororesin particles, and the formula (2) “Sb / Sa” is controlled to 0.5 or less. Further, when the content is 15% by mass or less, dispersibility of the fluororesin particles is obtained, and suitable light transmittance and film strength are obtained.

  The content of the metal oxide particles with respect to the total solid content of the charge transport layer 6 is preferably 30% by mass or more and 40% by mass or less, and the content of the metal oxide particles with respect to the total solid content of the charge transport layer 6 is By being 30% by mass or more, the charge transport layer 6 is sufficiently modified, and “Sb / Sa” in the formula (2) is controlled to 0.5 or less. Further, when the content is 40% by mass or less, the dispersibility of the metal oxide particles is obtained, and the occurrence of aggregation is suppressed.

  Examples of the fluororesin particles used for the charge transport layer 6 include a tetrafluoroethylene resin, a trifluoride ethylene resin, a hexafluoropropylene resin, a vinyl fluoride resin, a vinylidene fluoride resin, a difluorodiethylene chloride resin, and the like. It is desirable to select one type or two or more types from among these copolymers, particularly tetrafluoroethylene resin and vinylidene fluoride resin.

The primary particle size of the fluororesin particles is preferably 0.05 μm or more and 1 μm or less, and more preferably 0.1 μm or more and 0.5 μm or less. When the primary particle size is 0.05 μm or more, aggregation during dispersion is suppressed, and when it is 1 μm or less, occurrence of image quality defects is suppressed.
The primary particle size of the fluororesin particles was observed with a scanning electron microscope, and the average value of the major axis lengths of 100 particles was defined as the average primary particle size. The numerical values described in this specification are measured by the method.

As the metal oxide particles used for the charge transport layer 6, it is desirable to select one or more of silicon dioxide, alumina, zirconia, magnesium oxide and the like, and silicon dioxide and alumina are particularly desirable.
Furthermore, the metal oxide particles are preferably coated with a material having an aromatic functional group. Examples of the aromatic functional group include a phenyl ring, phenylethyl, naphthalene ring, and ethylene ring.

The metal oxide particles preferably have a specific surface area of 300 m ² / g or less, and more preferably 200 m ² / g or less. When the specific surface area is 300 m ² / g or less, inhibition of dispersion with respect to the fluororesin particles is suppressed.
In addition, the value of the BET specific surface area measured by Shimadzu powder specific surface area measuring apparatus SS-100 is used for the specific surface area of metal oxide particles. The numerical values described in this specification are measured by the method.

  In the charge transport layer 6 in the present embodiment, a fluorine-modified silicone oil represented by the following structure (I) may be added.

(In the structure (I), m and n represent an integer of 1 or more, and X represents a group containing a fluorine atom.)

  As this fluorine-modified silicone oil, those having a fluoroalkyl group as X in the structure (I) are preferably used.

  An arbitrary amount of the fluorine-modified silicone oil is added, but the range of 0.1 ppm to 1000 ppm is desirable in the coating solution for forming the charge transport layer 6, and more preferably 0.5 ppm to 500 ppm. .

  In addition to the above components, the charge transport layer 6 may contain a charge transport material for causing the intrinsic function of the charge transport layer 6 and a binder resin. Examples of such charge transport materials include 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 and other pyrazoline derivatives, triphenylamine, N, N′-bis (3,4-dimethylphenyl) biphenyl Aromatic tertiary amino compounds such as -4-amine, tri (p-methylphenyl) aminyl-4-amine, dibenzylaniline, N, N′-bis (3-methylphenyl) -N, N′-diphenyl Aromatic tertiary diamino compounds such as benzidine, 3- (4′-dimethylaminophenyl) -5,6-di- (4′-methoxyphenyl) -1, 1,2,4-triazine derivatives such as 1,4-triazine, hydrazone derivatives such as 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, 6-hydroxy-2 Benzofuran derivatives such as 1,3-di (p-methoxyphenyl) benzofuran, α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N-diphenylaniline, enamine derivatives, carbazole such as N-ethylcarbazole 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, Full such as 5,7-tetranitro-9-fluorenone Examples thereof include an electron transport material such as an oleone 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. These charge transport materials are used alone or in combination of two or more.

  Examples of the binder resin in the charge transport layer 6 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 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-anhydrous Insulating resins such as maleic acid resin, silicone resin, phenol-formaldehyde resin, polyacrylamide resin, polyamide resin, chlorine rubber, and polyvinylcarbazole, polyvinyl Anthracene, organic photoconductive polymers such as polyvinyl pyrene, and the like. These binder resins are used alone or in combination of two or more.

  The charge transport layer 6 is formed using a coating solution in which the above components are added to a solvent. Examples of the solvent used for forming the charge transport layer 6 include known organic solvents such as aromatic hydrocarbon solvents such as toluene and chlorobenzene, methanol, ethanol, n-propanol, iso-propanol, and n-butanol. Aliphatic alcohol solvents, ketone solvents such as acetone, cyclohexanone and 2-butanone, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, cyclic or straight chain such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether Examples include chain ether solvents, ester solvents such as methyl acetate, ethyl acetate, and n-butyl acetate. These solvents are 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. The mixing ratio of the charge transport material and the binder resin is preferably 10: 1 to 1: 5.

  Examples of the dispersion method of the coating liquid for dispersing the fluororesin particles in the charge transport layer 6 include a media disperser such as a ball mill, a vibration ball mill, an attritor, a sand mill, a horizontal sand mill, an agitator, an ultrasonic disperser, a roll mill, Medialess dispersers such as high-pressure homogenizers and nanomizers are used. 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.

  As a method of applying the coating liquid for forming the charge transport layer 6 thus obtained on the charge generation layer 5, dip coating method, push-up coating method, wire bar coating method, spray coating method, blade coating method Ordinary methods such as knife coating and curtain coating are used. The film thickness of the charge transport layer is desirably set in the range of 5 μm to 50 μm, more desirably 10 μm to 40 μm.

  Further, additives such as an antioxidant, a light stabilizer and a heat stabilizer may be added to each layer constituting the photosensitive layer 3 described above. For example, examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds. Examples of light stabilizers include derivatives such as benzophenone, benzoazole, dithiocarbamate, and tetramethylpipen.

  The photoconductor according to the exemplary embodiment is suitably used as a photoconductor as a latent image holding member in an electrophotographic image forming apparatus, for example.

<Image forming apparatus and process cartridge>
Next, the image forming apparatus and the process cartridge according to the present embodiment will be described.
The image forming apparatus according to the present embodiment forms an electrostatic latent image by exposing the surface of the photosensitive member, the charging device for charging the photosensitive member, and the charging device for charging the photosensitive member. A latent image forming device, a developing device for developing the electrostatic latent image formed on the surface of the photoconductor to form a toner image, and the toner image formed on the surface of the photoconductor on a recording medium. The image forming apparatus includes: a transfer device that transfers to a surface; and a cleaning device that cleans the surface of the photoreceptor.
The process cartridge according to the present embodiment is detachable from the image forming apparatus. The photosensitive member according to the present embodiment, the charging device that charges the photosensitive member, and the surface of the charged photosensitive member. A latent image forming device that forms an electrostatic latent image by exposing the toner, a developing device that develops the electrostatic latent image formed on the surface of the photoconductor to form a toner image, and a surface formed on the surface of the electrophotographic photoconductor. And a transfer device that transfers the toner image onto the surface of the recording medium and at least one selected from the group of cleaning devices that clean the surface of the photoreceptor.
Next, the image forming apparatus and the process cartridge according to the present embodiment will be described in detail with reference to the drawings.

  FIG. 2 is a cross-sectional view schematically showing a basic configuration of a preferred example of the image forming apparatus according to the present embodiment. The image forming apparatus illustrated in FIG. 2 includes the above-described photoconductor 11 according to the present embodiment, a contact charging type charging device 12 that charges the photoconductor 11, a power source 13 connected to the charging device 12, and the charging device 12. An exposure device 14 that exposes the photosensitive member 11 charged by the exposure device 14 to form an electrostatic latent image, a developing device 15 that develops the electrostatic latent image formed by the exposure device 14 with toner, and forms a toner image; The image forming apparatus includes a transfer device 16 that transfers a toner image formed by the developing device 15 to a recording medium 500, a cleaning device 17, and a charge removal device 18. In addition, the aspect in which the static elimination apparatus 18 is not provided may be sufficient.

  The charging device 12 has a charging roll, and a voltage is applied to the charging roll when charging the photoreceptor 11. As the voltage range, the DC voltage is preferably positive or negative 50V or more and 2000V or less depending on the required charging potential of the photoreceptor. Moreover, when an alternating voltage is superimposed, the peak-to-peak voltage is preferably 400 V or more and 1800 V or less. The frequency of the AC voltage is preferably 50 Hz or more and 20,000 Hz or less.

  As the charging roll, one provided with an elastic layer, a resistance layer, a protective layer, etc. on the outer peripheral surface of the core material is preferably used. Even if the charging roll is brought into contact with the photosensitive member 11 and does not have a driving unit, it rotates at the same peripheral speed as the photosensitive member 11 and functions as a charging unit. May be charged by rotating at different peripheral speeds. The applied voltage may be a DC voltage or a DC voltage with an AC voltage superimposed on it.

  As the exposure device 14, an optical system device that can perform imagewise exposure such as a semiconductor laser, an LED (Light Emitting Diode), and a liquid crystal shutter on the surface of the photosensitive member 11 is used.

  As the developing device 15, a conventionally known developing device using a regular or reversal developer such as a one-component or two-component developer is used. The shape of the toner used in the developing device 15 is not particularly limited, and an irregular shape, a spherical shape, or other specific shapes are also used.

  As the transfer device 16, a roller-type contact charging member, a contact-type transfer charger using a belt, a film, a rubber blade, or the like, a scorotron transfer charger using a corona discharge, a corotron transfer charger, etc. Is mentioned.

  The cleaning device 17 is for removing residual toner, paper dust, and the like adhering to the surface of the photoconductor 11 after the transfer process, and the photoconductor 11 thus cleaned is repeatedly subjected to the above image forming process. Provided. As the cleaning device 17, in addition to a cleaning blade, brush cleaning, roll cleaning, or the like is used. Among these, it is preferable to use a cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber.

  The image forming apparatus according to the present embodiment may further include an erase light irradiation device as the charge removal device 18 as shown in FIG. Alternatively, a brush or film having a charge eliminating function may be used instead. Thereby, when the photoconductor 11 is repeatedly used, a phenomenon that the residual potential of the photoconductor 11 is brought into the next cycle is prevented.

Next, the image forming apparatus will be described in other forms.
FIG. 3 is a cross-sectional view schematically showing a basic configuration of another example of the image forming apparatus according to the present embodiment. An image forming apparatus 200 shown in FIG. 3 is an intermediate transfer type image forming apparatus. In the housing 400, four photoconductors 401a to 401d (for example, the photoconductor 401a is yellow, the photoconductor 401b is magenta, and the photoconductor 401c is cyan, The photosensitive member 401d forms an image having a black color) and is arranged in parallel along the intermediate transfer belt 409.
Here, the photoconductors 401a to 401d mounted on the image forming apparatus 200 are the photoconductors according to the above-described embodiment.

  Each of the photoreceptors 401a to 401d rotates in a predetermined direction (counterclockwise in the drawing), and the charging rolls 402a to 402d, the developing devices 404a to 404d, and the primary transfer rolls 410a to 410d along the rotation direction. Cleaning blades 415a to 415d are arranged. Each of the developing devices 404a to 404d can supply toner of four colors, yellow, magenta, cyan, and black, contained in the toner cartridges 405a to 405d, and the primary transfer rolls 410a to 410d are respectively intermediate. The photoconductors 401a to 401d are in contact with each other through the transfer belt 409.

  Further, a laser light source 403 as an example of an exposure apparatus is disposed at a predetermined position in the housing 400, and laser light emitted from the laser light source 403 is irradiated on the surfaces of the charged photoconductors 401a to 401d. The Thus, the charging, exposure, development, primary transfer, and cleaning processes are sequentially performed in the rotation process of the photoconductors 401a to 401d, and the toner images of the respective colors are transferred onto the intermediate transfer belt 409 in an overlapping manner. The intermediate transfer belt 409 is supported with a tension determined by a drive roll 406, a counter roll 408, and a tension roll 407, and can rotate without causing deflection due to the rotation of these rolls. Further, the secondary transfer roll 413 is disposed so as to come into contact with the counter roll 408 via the intermediate transfer belt 409. The intermediate transfer belt 409 that has passed through the region sandwiched between the opposing 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 the next image forming process. Repeatedly served.

  In addition, a recording medium container 411 is provided at a predetermined position in the housing 400, and the recording medium 500 such as paper in the recording medium container 411 is moved by the transfer roll 412 and the intermediate transfer belt 409 and the secondary transfer roll. The sheet is sequentially transferred to a region sandwiched by 413 and further to a region sandwiched by 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. Also good. In the case of a belt shape, conventionally known resins are used as the resin material used as 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 polyetheretherketone and polyamide, and resin materials containing these as main raw materials. Further, a resin material and an elastic material may be blended and used.

Next, an example of the process cartridge according to the present embodiment will be described.
FIG. 4 is a cross-sectional view schematically showing a basic configuration of a preferred example of the process cartridge according to the present embodiment. In the process cartridge 300, a charging device 308, a developing device 311, a cleaning device 313, an opening portion 318 for exposure, and an opening portion 317 for static elimination exposure are combined using a mounting rail 316 together with the photosensitive member 307. It has become.

  The process cartridge 300 is detachable from an image forming apparatus main body including a transfer device 312, a fixing device 315, and other components not shown, and constitutes an image forming apparatus together with the image forming apparatus main body. To do.

  The recording medium 500 used in the present embodiment is not particularly limited as long as it is a medium that transfers a toner image formed on a photoreceptor. For example, when transferring directly from a photoreceptor to a recording medium such as paper, paper or the like is the recording medium. When an intermediate transfer member is used, the intermediate transfer member is a recording medium.

  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 at all.

Example 1
<Production of electrophotographic photoreceptor>
(Formation of undercoat layer)
100 parts by mass of zinc oxide (average particle size: 70 nm, manufactured by Teica, specific surface area value: 15 m ² / g) is stirred and mixed with 500 parts by mass of methanol, and KBM603 (manufactured by Shin-Etsu Chemical Co., Ltd.) 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, and baking was performed at 120 ° C. for 3 hours to obtain zinc oxide particles subjected to surface treatment with a silane coupling agent.

  60 parts by mass of the surface-treated zinc oxide particles, 0.6 parts by mass of alizarin, 13.5 parts by mass of blocked isocyanate (Sumidule 3173, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent, and butyral resin ( A solution prepared by dissolving 15 parts by mass of BM-1 (manufactured by Sekisui Chemical Co., Ltd.) in 85 parts by mass of methyl ethyl ketone was prepared. 38 parts by mass of the solution and 25 parts by mass of methyl ethyl ketone were mixed, and dispersed for 4 hours with a sand mill using glass beads having a diameter of 1 mm 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 to obtain a coating liquid for an undercoat layer. It was. This coating solution was applied on an aluminum support having a diameter of 30 mm by a dip coating method, followed by drying and curing at 180 ° C. for 40 minutes to form an undercoat layer having a thickness of 25 μm.

(Formation of charge generation layer)
Next, as a charge generating 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 °. 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 Co., Ltd.), and 300 parts by mass of n-butyl alcohol was prepared using glass beads having a diameter of 1 mm. The resultant was dispersed in a sand mill for 4 hours to obtain a coating solution for a charge generation layer. This charge generation layer coating solution was dip-coated on the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm.

(Formation of charge transport layer)
Next, 100 parts by mass of silicon dioxide (average particle size: 40 nm, manufactured by Nippon Aerosil Co., Ltd., specific surface area value: 50 m ² / g) as metal oxide particles was used as a silane coupling agent, and phenyltrimethoxysilane was sprayed. Baking was performed at 120 ° C. for 3 hours to obtain silicon dioxide particles subjected to surface treatment with a silane coupling agent. Thereafter, 5 parts by mass of surface-treated silicon dioxide particles, 1.5 parts by mass of tetrafluoroethylene resin particles (primary particle size: 0.2 μm) as fluororesin particles, and fluorine-based graft polymer (GF300, Toa Gosei Co., Ltd.) Manufactured, weight average molecular weight 30,000) 0.01 parts by mass together with 4 parts by mass of tetrahydrofuran and 1 part by mass of toluene at a liquid temperature of 20 ° C., stirred and mixed for 48 hours, and a tetrafluoroethylene resin particle suspension ( A liquid) was obtained. Next, 2 parts by mass of N, N′-bis (3-methylphenyl) -N, N′-diphenylbenzidine, N, N′-bis (3,4-dimethylphenyl) biphenyl-4-amine as a charge transport material 2 parts by mass, 6 parts by mass of bisphenol Z-type polycarbonate resin (viscosity average molecular weight: 40,000), 0.1 part by mass of 2,6-di-tert-butyl-4-methylphenol as an antioxidant were mixed and tetrahydrofuran was mixed 24 parts by mass and 11 parts by mass of toluene were mixed and dissolved (Liquid B). After the A liquid was added to the B liquid and stirred and mixed, the pressure was increased to 500 kgf / cm ² using a high pressure homogenizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.) equipped with a through-type chamber having a fine flow path. 100 ppm of fluorine-modified silicone oil (trade name: FL-100, manufactured by Shin-Etsu Silicone Co., Ltd.) was added to the liquid obtained by repeating the dispersion treatment six times, and stirred sufficiently to obtain a coating liquid for forming a charge transport layer.

  The content of the fluororesin particles (tetrafluoroethylene resin particles) with respect to the total solid content of the charge transport layer is 9.3% by mass, and the metal oxide particles (silicon dioxide) with respect to the total solid content of the charge transport layer. ) Content is 31% by mass.

  This coating solution was applied onto the charge generation layer and dried at 115 ° C. for 40 minutes to form a charge transport layer having a thickness of 34 μm, thereby producing the desired electrophotographic photosensitive member.

(Example 2)
In the coating liquid for forming a charge transport layer, as described in Example 1, except that the addition amounts of tetrafluoroethylene resin particles as fluororesin particles and silicon dioxide particles as metal oxide particles were changed as follows. An electrophotographic photosensitive member was produced by this method.
Tetrafluoroethylene resin particles: 1.2 parts by mass Silicon dioxide: 5 parts by mass

(Example 3)
In the coating liquid for forming a charge transport layer, as described in Example 1, except that the addition amounts of tetrafluoroethylene resin particles as fluororesin particles and silicon dioxide particles as metal oxide particles were changed as follows. An electrophotographic photosensitive member was produced by this method.
Tetrafluoroethylene resin particles: 0.2 parts by mass Silicon dioxide: 5 parts by mass

Example 4
In the coating liquid for forming a charge transport layer, as described in Example 1, except that the addition amounts of tetrafluoroethylene resin particles as fluororesin particles and silicon dioxide particles as metal oxide particles were changed as follows. An electrophotographic photosensitive member was produced by this method.
Tetrafluoroethylene resin particles: 0.15 parts by mass Silicon dioxide: 5 parts by mass

(Comparative Example 1)
In the coating liquid for forming a charge transport layer, as described in Example 1, except that the addition amounts of tetrafluoroethylene resin particles as fluororesin particles and silicon dioxide particles as metal oxide particles were changed as follows. An electrophotographic photosensitive member was produced by this method.
Tetrafluoroethylene resin particles: 1.2 parts by mass Silicon dioxide: 0 parts by mass

(Comparative Example 2)
In the coating liquid for forming a charge transport layer, as described in Example 1, except that the addition amounts of tetrafluoroethylene resin particles as fluororesin particles and silicon dioxide particles as metal oxide particles were changed as follows. An electrophotographic photosensitive member was produced by this method.
Tetrafluoroethylene resin particles: 0.2 parts by mass Silicon dioxide: 0 parts by mass

(Comparative Example 3)
In the coating liquid for forming a charge transport layer, as described in Example 1, except that the addition amounts of tetrafluoroethylene resin particles as fluororesin particles and silicon dioxide particles as metal oxide particles were changed as follows. An electrophotographic photosensitive member was produced by this method.
Tetrafluoroethylene resin particles: 0 parts by mass Silicon dioxide: 5 parts by mass

(Comparative Example 4)
In the coating solution for charge transport layer formation, the addition amount of tetrafluoroethylene resin particles as fluorine resin particles, silicon dioxide particles as metal oxide particles, bisphenol Z-type polycarbonate resin, and fluorine-modified silicone oil was changed as follows: Except for the above, an electrophotographic photosensitive member was produced by the method described in Example 1.
Tetrafluoroethylene resin particles: 0 parts by mass Silicon dioxide: 0 parts by mass Bisphenol Z-type polycarbonate resin: 16 parts by mass Fluorine-modified silicone oil: 200 ppm

(Comparative Example 5)
In the coating liquid for forming a charge transport layer, as described in Example 1, except that the addition amounts of tetrafluoroethylene resin particles as fluororesin particles and silicon dioxide particles as metal oxide particles were changed as follows. An electrophotographic photosensitive member was produced by this method.
Tetrafluoroethylene resin particles: 0 parts by mass Silicon dioxide: 0 parts by mass

(Comparative Example 6)
On the surface of the photoreceptor produced by the method described in Comparative Example 5, a photoreceptor having a protective layer provided by the following method was produced.
(Formation of protective layer)
4.5 parts by mass of a compound represented by the following structure (II), 15 parts by mass of isopropyl alcohol, 9 parts by mass of tetrahydrofuran, and 0.9 parts by mass of distilled water were mixed, and an ion exchange resin (Amberlyst 15E) was mixed therewith. ) Was added, and the mixture was stirred at room temperature (22 ° C) for hydrolysis for 2 hours. Furthermore, 0.5 parts by mass of butyral resin, 5.5 parts by mass of resol type phenol resin (PL-2215, manufactured by Gunei Chemical Co., Ltd.) and 0.05 parts by mass of dimethylpolysiloxane were added to form a coating solution for forming a protective layer. Prepared. This protective layer-forming coating solution was applied onto the charge transport layer by a dip coating method and dried at 150 ° C. for 35 minutes to form a protective layer having a thickness of 10 μm.

(Evaluation test)
-Friction test with sapphire needles-
Using the photoconductors of the above examples and comparative examples, the above-described “friction test with sapphire needles” was performed, and the values of “Sa, Sb / Sa, Ss” were obtained. The results are summarized in Table 1. In Table 1, “-” in the “friction test” is not carried out, and “x” means that the amount of wear exceeds the film thickness of the charge transport layer before reaching the number of frictions determined in the friction test.

-Image formation test (image evaluation)-
Further, each of the photoconductors of the above examples and comparative examples was mounted on a full color printer Docu Center Color f450 drum cartridge manufactured by Fuji Xerox Co., Ltd., and an image formation test was performed. In the image forming test, under an environment of 25 ° C. and 80 RH%, an image quality pattern having an average image density of 5% was continuously printed on A4 paper after 25,000 sheets were printed, and the image quality was evaluated. The results are summarized in Table 1.
The evaluation criteria for image evaluation are as follows.
○: No image quality failure △: Not image flow, but uneven image quality occurs in part ×: Image quality defect due to image flow occurs

1, 11, 307, 401a, 401b, 401c, 401d Photoconductor, 2 conductive substrate, 3 photosensitive layer, 4 undercoat layer, 5 charge generation layer, 6 charge transport layer, 12, 308 charging device, 13 power supply, 14 Exposure device, 15, 311, 404a, 404b, 404c, 404d Developing device, 16, 312 Transfer device, 17, 313 Cleaning device, 18 Static elimination device, 200 Image forming device, 300 Process cartridge, 315 Fixing device, 316 Mounting rail, 317 Opening for static elimination exposure, 318 Opening for exposure, 400 Housing, 402a, 402b, 402c, 402d Charging roll, 403 Laser light source, 405a, 405b, 405c, 405d Toner cartridge, 406 Drive roll, 407 Tension Roll, 408 opposite Roll, 409 Intermediate transfer belt, 410a, 410b, 410c, 410d Primary transfer roll, 411 Recording medium container, 412 Transfer roll, 413 Secondary transfer roll, 414 Fixing roll, 415a, 415b, 415c, 415d, 416 Cleaning blade 500 recording media

Claims (4)

A conductive substrate;
A photosensitive layer comprising an outermost surface layer containing fluororesin particles and metal oxide particles and satisfying the following formulas (1) and (2):
An electrophotographic photosensitive member having:
Formula (1) 0.05 (μm / 1 reciprocation) ≦ Sa ≦ 0.2 (μm / 1 reciprocation)
Formula (2) Sb / Sa ≦ 0.5
(In the above formula (1) and formula (2), Sa repeatedly reciprocates at a speed of 5 mm / s while pressing a sapphire needle having a radius of curvature of 0.1 mm at the tip to the outermost surface layer with a load of 50 g. In the test for rubbing to a depth of 10 μm, the amount of wear per reciprocation in the region below the depth of 4 μm from the surface is represented, and Sb represents the amount of wear per reciprocation in the region of the depth of 4 μm to 10 μm from the surface in the test. To express.)   When the sapphire needle having a radius of curvature of 0.1 mm at the tip is pressed against the outermost surface layer with a load of 50 g, the total wear amount is less than 6 μm when it is rubbed by reciprocating 200 times at a speed of 5 mm / s. The electrophotographic photosensitive member according to claim 1. The electrophotographic photoreceptor according to claim 1 or 2,
A charging device for charging the electrophotographic photosensitive member;
A latent image forming device that exposes the surface of the charged electrophotographic photosensitive member to form an electrostatic latent image; and
A developing device for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member to form a toner image;
A transfer device for transferring the toner image formed on the surface of the electrophotographic photosensitive member to the surface of a recording medium;
A cleaning device for cleaning the surface of the electrophotographic photosensitive member;
An image forming apparatus comprising: It is detachable from the image forming apparatus,
The electrophotographic photosensitive member according to claim 1 or 2,
A charging device that charges the electrophotographic photosensitive member, a latent image forming device that exposes the surface of the charged electrophotographic photosensitive member to form an electrostatic latent image, and an electrostatic latent image formed on the surface of the electrophotographic photosensitive member. Developing device for developing image to form toner image, transfer device for transferring toner image formed on surface of electrophotographic photosensitive member to surface of recording medium, and cleaning device for cleaning surface of electrophotographic photosensitive member At least one selected from the group of:
A process cartridge comprising: