JP5861520B2 - Electrophotographic photosensitive member, image forming apparatus, and process cartridge - Google Patents

Description

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

In a so-called xerographic image forming apparatus, an electrophotographic photosensitive member is a member that forms an electrostatic latent image on its surface by charging its surface with a charging means and then selectively removing the charge with an exposure means. .
For example, Patent Document 1 states that “an electrophotographic photosensitive member having a photosensitive layer and a surface protective layer on a conductive support, and only a DC voltage is applied to a charging member disposed in contact with the photosensitive member. When charging the surface of the photoconductor, the relationship between the DC applied voltage Vdc (V), the dark potential Vd (V) of the photoconductor, and the discharge start voltage Vth (V) is | Vdc | − | Vd |> | Vth. In the electrophotographic photoreceptor satisfying | / 2, an electrophotographic photoreceptor in which the surface protective layer contains at least a phenol resin is disclosed.
Patent Document 2 states that “a charging member used as a charging unit is a roller-shaped charging member disposed in proximity to a photosensitive member, and the charging member is charged at a charging nip formed between the charging member and the photosensitive member. The total energy amount of the charged particles colliding satisfies 0.8 × 10 ⁻⁴ ≦ total energy amount of the charged particles / photoreceptor circumferential length (J / m ² · mm) ≦ 1.5 × 10 ⁻⁴ . A configuration is disclosed in which the photosensitive member is charged by applying a voltage in which an alternating voltage is superimposed on a direct current voltage to the charging member under the conditions.

Japanese Patent Laid-Open No. 2003-5412 JP 2005-99699 A

  An object of the present invention is to provide an electrophotographic photosensitive member that suppresses the occurrence of dot-like image defects.

The above problem is solved by the following means. That is,
A conductive substrate;
A photosensitive layer provided on the conductive substrate;
Wherein a photosensitive layer surface protective layer provided on, viewed contains a charge transport material, and at least one selected from compounds having the compound and melamine structure having a guanamine structure and a fluorine resin particles, the guanamine structure The total content of the compound having a melamine structure and the compound having the melamine structure is 0.1% by mass or more and 10% by mass or less with respect to the total solid content, and the content of the fluororesin particles is 30% with respect to the total solid content. A surface protective layer having a surface free energy of 45 mN / m or more and 95 mN / m or less.
An electrophotographic photosensitive member having:

The invention according to claim 2
The electrophotographic photosensitive member according to claim 1, wherein the surface of the surface protective layer has a ten-point average roughness Rz (JIS B 0601-1994) of 0.3 μm or more and 0.7 μm or less.

The invention according to claim 3
The electrophotographic photosensitive member according to claim 1 or 2,
A charging device comprising a roller-shaped charging member that rotates in contact with the electrophotographic photosensitive member, and charging the surface of the electrophotographic photosensitive member with the roller-shaped charging member;
An electrostatic latent image forming apparatus for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member;
A developing device for developing the electrostatic latent image with a developer to form a toner image;
A transfer device for transferring the toner image to a transfer medium;
An image forming apparatus.

The invention according to claim 4
The electrophotographic photosensitive member according to claim 1 or 2,
A charging device comprising a roller-shaped charging member that rotates in contact with the electrophotographic photosensitive member, and charging the surface of the electrophotographic photosensitive member with the roller-shaped charging member;
And a process cartridge that is detachably attached to the image forming apparatus.

  According to the first aspect of the present invention, the electrophotographic photosensitive member suppresses the occurrence of dot-like image defects compared to the case where the surface free energy of the surface protective layer composed of the cured film of the composition is out of the range. Is provided.

  According to the second aspect of the present invention, the occurrence of dot-like image defects is suppressed as compared with the case where the ten-point average roughness Rz of the surface protective layer composed of the cured film of the composition is out of the range. An electrophotographic photoreceptor is provided.

  According to the third and fourth aspects of the invention, there are provided an image forming apparatus and a process cartridge in which occurrence of dot-like image defects is suppressed.

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

  Hereinafter, embodiments of the electrophotographic photosensitive member, the image forming apparatus, and the process cartridge of the present invention will be described in detail.

<Electrophotographic photoreceptor>
The electrophotographic photoreceptor according to the exemplary embodiment includes a conductive substrate, a photosensitive layer provided on the conductive substrate, and a surface protective layer provided on the photosensitive layer.
The surface protective layer is at least selected from a charge transport material, a compound having a guanamine structure (hereinafter also referred to as “guanamine compound”) and a compound having a melamine structure (hereinafter also referred to as “melamine compound”). And an outermost surface layer having a surface free energy of 45 mN / m or more and 95 mN / m or less.

According to the electrophotographic photosensitive member according to this embodiment, an electrophotographic photosensitive member that suppresses the occurrence of dot-like image defects is provided.
The reason for this is not clear, but is thought to be due to the following reasons.

In an image forming apparatus provided with a charging device having a roller-shaped charging member that rotates in contact with the electrophotographic photosensitive member, the electrophotographic photosensitive member and the charging member are rotated while the device is being driven. Discharge occurs in the formed minute gap (referred to as “minute gap”), and the surface of the electrophotographic photosensitive member is charged.
However, when the apparatus is driven, the electrophotographic photosensitive member and the charging member are not stably rotated, for example, both or one of them alternately repeats stop and sudden rotation, or one pulls the other surface layer. In such a case, the shape of the minute gap is not stable, and the surface of the electrophotographic photosensitive member is unevenly charged. As a result, dot-like image defects (for example, white spots) may occur.
The above problem tends to be less likely to occur as the surface protective layer becomes worn and thin with use, but is likely to occur in the initial use of the electrophotographic photoreceptor.

  On the other hand, a technique is known in which the surface protective layer of an electrophotographic photoreceptor is composed of a cured film of a composition containing at least one of a guanamine compound and a melamine compound to improve wear resistance. In the electrophotographic photosensitive member having this surface protective layer, the rotation with the roller-shaped charging member is not stable, and the shape of the minute gap may not be stable. The crosslinked product of the guanamine compound and the crosslinked product of the melamine compound are It was thought to be the cause.

  On the other hand, the electrophotographic photoreceptor according to the exemplary embodiment has a surface free energy of 45 mN / m or more and 95 mN even when the surface protective layer is a cured film of a composition containing at least one of a guanamine compound and a melamine compound. / M or less, the rotation of the electrophotographic photosensitive member and the charging member is stabilized, the shape of the microgap is stabilized, and charging unevenness on the surface of the electrophotographic photosensitive member is unlikely to occur. . As a result, it is considered that the electrophotographic photosensitive member according to the present embodiment suppresses the occurrence of dot-like image defects from the initial use to a long period. The surface free energy of the surface protective layer is desirably 50 mN / m or more and 90 mN / m or less, and more desirably 55 mN / m or more and 85 mN / m or less.

The surface free energy of the surface protective layer of the electrophotographic photosensitive member according to this embodiment is calculated by measuring the contact angles of three types of solvents and applying the extended Fowkes theory.
The solvent used for the measurement of the contact angle is not particularly limited as long as the surface free energy and each of its components (dispersion force component, dipole component, hydrogen bond component) are known, and the combination of the three types is not particularly limited. Specific examples of the solvent include, for example, methylene iodide, bromobenzene, α-bromonaphthalene, tetrachloroethane, hexachlorobutadiene, water, glycerol, ethylene glycol, diethylene glycol, formamide, ethanol, n-hexadecane, n-hexane, tetra Decalin etc. are mentioned.
The contact angle is measured using a contact angle meter after placing the electrophotographic photosensitive member in an environment of temperature 23 ° C. (± 1 ° C.) / Relative humidity 55% (± 5%) for 24 hours or more. Do.

  The surface free energy of the surface protective layer of the electrophotographic photoreceptor according to the exemplary embodiment is adjusted by a component contained in the layer, that is, a component contained in the composition for forming the layer. In particular, it is adjusted according to the type and content of fluororesin particles, a fluororesin particle dispersant and a surfactant used as necessary. In addition, the surface free energy of the surface protective layer is adjusted by adjusting the temperature at which the composition for forming the layer is heated and cured.

  In the electrophotographic photoreceptor according to the exemplary embodiment, it is preferable that the 10-point average roughness Rz (JIS B 0601-1994) of the surface protective layer is 0.3 μm or more and 0.7 μm or less. When the ten-point average roughness Rz is in this range, the accompanying rotation of the electrophotographic photosensitive member and the charging member becomes more stable, and the occurrence of charging unevenness is further suppressed. The ten-point average roughness Rz of the surface of the surface protective layer is more preferably 0.4 μm or more and 0.6 μm or less.

  The ten-point average roughness Rz of the surface protective layer of the electrophotographic photosensitive member according to this embodiment is adjusted by the component contained in the layer, that is, the component contained in the composition for forming the layer. In particular, it is adjusted by the type and content of the component that forms a polymer or a crosslinked product (for example, a guanamine compound, a melamine compound, a reactive charge transport material used as necessary) and a surfactant used as necessary. The In addition, the ten-point average roughness Rz of the surface of the surface protective layer is adjusted by adjusting the temperature at which the composition for forming the layer is heated and cured.

Hereinafter, the electrophotographic photoreceptor according to the exemplary embodiment will be described in detail with reference to the drawings.
1 to 3 schematically show a cross section of a part of the electrophotographic photoreceptor 10 according to this embodiment.
An electrophotographic photoreceptor 10 shown in FIG. 1 has an undercoat layer 1 provided on a conductive support 4, a charge generation layer 2 and a charge transport layer 3 provided as a photosensitive layer on the undercoat layer 1, and A surface protective layer 5 serving as the outermost surface layer is provided.
The electrophotographic photoreceptor 10 shown in FIG. 2 includes a photosensitive layer having functions separated into a charge generation layer 2 and a charge transport layer 3 as in the electrophotographic photoreceptor 10 shown in FIG. A charge transport layer 3, a charge generation layer 2, and a surface protective layer 5 are sequentially provided on 1.
An electrophotographic photoreceptor 10 shown in FIG. 3 contains a charge generation material and a charge transport material in the same layer, that is, a single-layer type photosensitive layer 6 (charge generation / charge transport layer). A surface protective layer 5 is provided.
Hereinafter, each element will be described based on the electrophotographic photoreceptor 10 shown in FIG. 1 as a representative example. Note that the reference numerals are omitted.

(Conductive substrate)
Any conductive substrate may be used as long as it is conventionally used. For example, thin films (eg, metals such as aluminum, nickel, chromium, stainless steel, and films of aluminum, titanium, nickel, chromium, stainless steel, gold, vanadium, tin oxide, indium oxide, indium tin oxide (ITO), etc.) And a plastic film coated or impregnated with a conductivity-imparting agent, a plastic film coated or impregnated with a conductivity-imparting agent, and the like. The shape of the substrate is not limited to a cylindrical shape, and may be a sheet shape or a plate shape.

  When a metal pipe is used as the conductive substrate, the surface may be left as it is, and treatments such as mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, and wet honing have been performed in advance. Also good.

(Undercoat layer)
The undercoat layer is provided as necessary for the purpose of preventing light reflection on the surface of the conductive substrate and preventing inflow of unnecessary carriers from the conductive substrate to the photosensitive layer.

The undercoat layer includes, for example, a binder resin and, if necessary, other additives.
As the binder resin contained in the undercoat 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, Known polymer resin compounds such as polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol resin, phenol-formaldehyde resin, melamine resin, urethane resin, and charge transport group Examples thereof include charge transporting resins and conductive resins such as polyaniline. Among these, resins that are insoluble in the upper coating solvent are preferably used, and phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, epoxy resins, and the like are particularly preferably used.

  The undercoat layer may contain a metal compound such as a silicon compound, an organic zirconium compound, an organic titanium compound, or an organic aluminum compound.

  The ratio between the metal compound and the binder resin is not particularly limited, and is arbitrarily set within a range in which the desired electrophotographic photoreceptor characteristics can be obtained.

  Resin particles may be added to the undercoat layer in order to adjust the surface roughness. Examples of the resin particles include silicone resin particles and cross-linked polymethyl methacrylate (PMMA) resin particles. The surface may be polished after forming the undercoat layer for adjusting the surface roughness. As a polishing method, buffing, sandblasting, wet honing, grinding, or the like is used.

Here, the structure of the undercoat layer includes a structure containing at least a binder resin and conductive particles. Note that the conductive particles preferably have conductivity with a volume resistivity of less than 10 ⁷ Ω · cm, for example.

Examples of the conductive particles include metal particles (particles such as aluminum, copper, nickel, and silver), conductive metal oxide particles (particles such as antimony oxide, indium oxide, tin oxide, and zinc oxide), and conductive substance particles. (Carbon fiber, carbon black, particles of graphite powder) and the like. Among these, conductive metal oxide particles are preferable. Two or more kinds of conductive particles may be mixed and used.
In addition, the conductive particles may be subjected to a surface treatment with a hydrophobizing agent (for example, a coupling agent) or the like to adjust the resistance.
For example, the content of the conductive particles is preferably 10% by mass or more and 80% by mass or less, and more preferably 40% by mass or more and 80% by mass or less with respect to the binder resin.

In forming the undercoat layer, a coating solution for forming an undercoat layer in which the above components are added to a solvent is used.
In addition, as a method for dispersing particles in the coating solution for forming the undercoat layer, a media disperser such as a ball mill, a vibrating ball mill, an attritor, a sand mill, a horizontal sand mill, an agitator, an ultrasonic disperser, a roll mill, a high-pressure homogenizer, etc. Medialess dispersers are used. Here, examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high-pressure state, and a penetration method in which a fine flow path is dispersed in a high-pressure state. .

  Examples of the method for applying the coating liquid for forming the undercoat layer onto the conductive substrate include dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, and curtain coating. It is done.

  The thickness of the undercoat layer is preferably 15 μm or more, and more preferably 20 μm or more and 50 μm or less.

  Here, although not shown, an intermediate layer may be further provided between the undercoat layer and 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 resin compounds 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, etc. Examples thereof include organometallic compounds. These compounds may be used alone or as a mixture or polycondensate of a plurality of compounds. Among these, an organometallic compound containing zirconium or silicon is preferable in that it has a low residual potential, a small potential change due to the environment, and a small potential change due to repeated use.

In forming the intermediate layer, a coating solution for forming an intermediate layer in which the above components are added to a solvent is used.
As the coating method for forming the intermediate layer, usual methods such as a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, and a curtain coating method are used.

  In addition to improving the coatability of the upper layer, the intermediate layer also serves as an electrical blocking layer. However, if the film thickness is too large, the electrical barrier becomes too strong and the potential increases due to desensitization or repetition. May cause. Therefore, when forming the intermediate layer, it is preferable to set the film thickness within the range of 0.1 μm to 3 μm. In this case, the intermediate layer may be used as the undercoat layer.

(Charge generation layer)
The charge generation layer includes, for example, a charge generation material and a binder resin. Examples of such a charge generating material include phthalocyanine pigments such as metal-free phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, dichlorotin phthalocyanine, and titanyl phthalocyanine. A chlorogallium phthalocyanine crystal having strong diffraction peaks at least at 7.4 °, 16.6 °, 25.5 ° and 28.3 °, a 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) with respect to CuKα characteristic X-rays .2 °) at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 ° Hydroxygallium phthalocyanine crystals having strong diffraction peaks at 25.1 ° 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 having a strong diffraction peak at 0 ° can be mentioned. In addition, examples of the charge generation material include quinone pigments, perylene pigments, indigo pigments, bisbenzimidazole pigments, anthrone pigments, quinacridone pigments, and the like. These charge generation materials may be used alone or in combination of two or more.

Examples of the binder resin constituting 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 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 Examples thereof include resins, silicone resins, phenol-formaldehyde resins, polyacrylamide resins, polyamide resins, poly-N-vinylcarbazole resins. These binder resins may be used alone or in combination of two or more.
The mixing ratio of the charge generating material and the binder resin is preferably in the range of 10: 1 to 1:10, for example.

  When forming the charge generation layer, a coating solution for forming a charge generation layer in which the above components are added to a solvent is used.

  As a method for dispersing particles (for example, electrification generating material) in the coating solution for forming the charge generation layer, 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, or a roll mill. Medialess dispersers such as high-pressure homogenizers are used. Examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high-pressure state, and a penetration method in which a fine flow path is dispersed in a high-pressure state.

  Examples of the method for applying the charge generation layer forming coating liquid on the undercoat layer include dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, and curtain coating. It is done.

  The thickness of the charge generation layer is desirably set in the range of 0.01 μm to 5 μm, more desirably 0.05 μm to 2.0 μm.

(Charge transport layer)
The charge transport layer includes a charge transport material and, if necessary, a binder resin.

  Examples of the charge transport material include oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1- [ Pyrazoline derivatives such as pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, 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′-diphenylbenzidine Aromatic tertiary diamino compounds such as 3- (4′-dimethylaminophenyl) -5,6-di- (4′-methoxyphenyl) -1,2,4 1,2,4-triazine derivatives such as triazine, hydrazone derivatives such as 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, 6-hydroxy-2,3- Benzofuran derivatives such as di (p-methoxyphenyl) benzofuran, α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N-diphenylaniline, enamine derivatives, carbazole derivatives such as N-ethylcarbazole, poly -Hole transport materials such as -N-vinylcarbazole and its derivatives, quinone compounds such as chloranil and broanthraquinone, tetraanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2,4,5,7 -Fluorenone such as tetranitro-9-fluorenone Examples thereof include an electron transport material such as a compound, a xanthone compound, and a thiophene compound, and a polymer having a group consisting of the above-described compounds in a main chain or a side chain. These charge transport materials may be used alone or in combination of two or more.

Examples of the binder resin constituting the charge transport 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 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 maleic acid Insulating resins such as acid resins, silicone resins, phenol-formaldehyde resins, polyacrylamide resins, polyamide resins, chlorine rubber, and polyvinylcarbazole and polyvinylanthracene Organic photoconductive polymers such as polyvinyl pyrene, and the like. These binder resins may be used alone or in combination of two or more.
The blending ratio between the charge transport material and the binder resin is preferably 10: 1 to 1: 5, for example.

  The charge transport layer is formed using a charge transport layer forming coating solution in which the above components are added to a solvent.

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

As a method for applying the charge transport layer forming coating solution on the charge generation layer, dip coating method, push-up coating method, wire bar coating method, spray coating method, blade coating method, knife coating method, curtain coating method, etc. The method is 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.

(Surface protective layer)
The surface protective layer is the outermost surface layer provided on the photosensitive layer. The surface protective layer is composed of a charge transporting cured film of a composition containing a charge transporting material and at least one selected from a guanamine compound and a melamine compound. The surface protective layer may be composed of a charge transportable cured film of a composition further containing fluororesin particles, a fluorinated alkyl group-containing copolymer, a surfactant and the like, if necessary.

[Charge transport material]
Examples of the charge transport material include the compounds described as being contained in the charge transport layer. When such a charge transport material is used, a binder resin may be used in combination as necessary. Examples of the binder resin include the resins already described as being included in the charge transport layer.

  As the charge transport material, a reactive charge transport material is desirable from the viewpoint of making the surface protective layer a cured film having higher strength.

-Reactive charge transport material-
The reactive charge transport material may be at least one of charge transport materials having at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. In particular, the reactive charge transport material is preferably a charge transport material having at least two (or three) substituents selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. As described above, the reactive functional group (substituent) increases in the charge transport material, so that the crosslink density is increased and a cross-linked film having higher strength is easily obtained.

The reactive charge transport material is preferably a compound represented by the following general formula (A) from the viewpoint of suppressing wear of the foreign matter removing member and suppressing wear of the electrophotographic photosensitive member.
^{Fr - ((- R 11 -Z} ) n1 (R 12) n2 -Y) n3 ...... general formula (A)
In general formula (A), Fr represents an organic group (charge transport skeleton) derived from a compound having charge transport ability. R ¹¹ and R ¹² each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms, Z represents an oxygen atom, NH, or a sulfur atom, Y represents —OH, —OCH ₃ , -NH _2, represents an -SH or -COOH. n1 represents 0 or 1, n2 represents 0 or 1, and n3 represents an integer of 1 or more and 4 or less.

  In general formula (A), an arylamine derivative is preferably used as the compound having charge transportability in the “organic group derived from the compound having charge transportability” represented by Fr. Preferred examples of the arylamine derivative include a triphenylamine derivative and a tetraphenylbenzidine derivative.

  The compound represented by the general formula (A) is preferably a compound represented by the following general formula (A-1). The compound represented by the general formula (A-1) is particularly excellent in charge mobility, stability against oxidation and the like.

In general formula (A-1), Ar ^A1 , Ar ^A2 , Ar ^A3 and Ar ^A4 each independently represent a substituted or unsubstituted aryl group, and may be the same or different.
Ar ^A5 represents a substituted or unsubstituted aryl group or a substituted or unsubstituted arylene group.
D represents — (— R ¹¹ —Z) _n1 (R ¹² ) _n2 —Y (where R ¹¹ and R ¹² each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms; Z represents an oxygen atom, NH, or a sulfur atom, Y represents _-OH, -OCH _3, -NH 2, represents an -SH or -COOH, n1 represents 0 or 1, n2 represents 0 or 1. ). e1 to e5 each independently represents 0 or 1, and the total number of D is 1 or more and 4 or less. k represents 0 or 1;
Regarding Ar ^{A1 to} Ar ^A5 , the substituents in the substituted aryl group and the substituted arylene group include those other than D, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, substituted or unsubstituted And an aryl group having 6 to 10 carbon atoms.

In the general formula (A-1), represented by D _{^{'- (- R 11 -Z) n1}} (R 12) n2 -Y ^{"is, R 11} and ^{R 12} are independently a number of 1 to 5 carbon respectively A linear or branched alkylene group, n1 is preferably 1, n2 is preferably 1, and Z is preferably oxygen.

  In general formula (A-1), the total number of D corresponds to n3 in general formula (A), preferably 2 or more and 4 or less, and more preferably 3 or more and 4 or less. When the total number of D is 2 or more and 4 or less, preferably 3 or more and 4 or less in one molecule, the crosslinking density increases and a crosslinked film with higher strength can be obtained.

In general formula (A-1), Ar ^A1 , Ar ^A2 , Ar ^A3 and Ar ^A4 are preferably any of the following formulas (1) to (7). In addition, following formula (1) thru | or (7) can be connected with Ar ^{< A1>} , Ar <^A2> , Ar ^<A3>, and Ar ^<A4> "-(D) _e " (however, e shows either e1 thru | or e5). Shown with.

In the formulas (1) to (7), R ¹³ is phenyl substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Represents one selected from the group consisting of a group, an unsubstituted phenyl group, and an aralkyl group having 7 to 10 carbon atoms, wherein R ¹⁴ , R ¹⁵ and R ¹⁶ are each independently a hydrogen atom, 1 to 4 carbon atoms An alkyl group having 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom. 1 represents one selected from the group, Ar represents a substituted or unsubstituted arylene group, D and e are the same as “D” and “e1 to e5” in formula (A-1), and s is 0 Or 1 , T is an integer of 1 to 3.
Here, as Ar in Formula (7), what is represented by following formula (8) or (9) is desirable.

In formula (8) or (9), R ¹⁷ and R ¹⁸ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. This represents one type selected from the group consisting of a substituted phenyl group, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, and t represents an integer of 1 to 3.
Z ′ in the formula (7) is preferably represented by any one of the following formulas (10) to (17).

In formulas (10) to (17), R ¹⁹ and R ²⁰ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. It represents one selected from the group consisting of a substituted phenyl group, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, W represents a divalent group, and q and r are respectively 1 represents an integer of 1 to 10, and t represents an integer of 1 to 3.
W in the formulas (16) and (17) is preferably any one of divalent groups represented by the following (18) to (26). However, in formula (25), u represents an integer of 0 or more and 3 or less.

In the general formula (A-1), Ar ^A5 is an aryl group of the above formulas (1) to (7) exemplified in the explanation of Ar ^{A1 to} Ar ^A4 when k is 0, and when k is 1 Is an arylene group obtained by removing a hydrogen atom from the aryl groups of the above formulas (1) to (7).

  Specific examples of the compound represented by the general formula (A) include the following compounds, but are not limited thereto.

  The reactive charge transport material includes at least one of a reactive charge transport material having an alkoxy group and a reactive charge transport material having a hydroxyl group from the viewpoints of wear resistance, image quality characteristics, electrical characteristics and the like of the electrophotographic photoreceptor. It is desirable.

  From the viewpoint of the electrical properties of the surface protective layer, the content of the charge transport material (especially the reactive charge transport material) is, for example, that the solid content concentration in the composition for formation is relative to the total component (solid content) of the layer 80% by mass or more, desirably 90% by mass or more, and more desirably 95% by mass or more. In addition, solid content concentration in said composition for formation is a density | concentration with respect to all the structural components (solid content) except these, when using a fluororesin particle and a fluoroalkyl group containing copolymer.

[Guanamine compounds, melamine compounds]
The composition for forming the surface protective layer contains at least one selected from a guanamine compound and a melamine compound. The wear resistance of the electrophotographic photoreceptor is improved by the guanamine compound and the melamine compound.
The surface protective layer includes at least one polymer selected from a guanamine compound and a melamine compound or a crosslinked product, and when a reactive charge transport material is used as the charge transport material, the reactive charge transport material, guanamine, It comprises a polymer or a crosslinked product with at least one selected from a compound and a melamine compound.

-Guanamine compounds-
A guanamine compound is a compound having a guanamine skeleton (structure), and examples thereof include acetoguanamine, benzoguanamine, formoguanamine, steroguanamine, spiroguanamine, and cyclohexylguanamine.
The guanamine compound is particularly preferably at least one of a compound represented by the following general formula (B) and a multimer thereof. Here, the multimer is an oligomer polymerized using the compound represented by the general formula (B) as a structural unit, and the degree of polymerization thereof is, for example, 2 or more and 200 or less (preferably 2 or more and 100 or less). The compound represented by the general formula (B) or a multimer thereof may be used alone or in combination of two or more. When the compound represented by the general formula (B) is used as a mixture of two or more kinds or as a multimer (oligomer) having the compound as a structural unit, the solubility in a solvent is improved.

In General Formula (B), R ^B1 represents a linear or branched alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, or a substituted or unsubstituted carbon. This represents an alicyclic hydrocarbon group having a number of 4 or more and 10 or less. R ^{B2 to} R ^B5 each independently represent a hydrogen atom, —CH ₂ —OH, or —CH ₂ —O—R ^B6 . R ^B6 represents a linear or branched alkyl group having 1 to 10 carbon atoms.

When R ^B1 is a linear or branched alkyl group having 1 to 10 carbon atoms, the carbon number is preferably 1 or less and 8 or more, and more preferably 1 or more and 5 or less.
When R ^B1 is a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, it preferably has 6 to 8 carbon atoms. Examples of the substituent when the phenyl group is substituted include a methyl group, an ethyl group, and a propyl group.
When R ^B1 is a substituted or unsubstituted alicyclic hydrocarbon group having 4 to 10 carbon atoms, it preferably has 5 to 8 carbon atoms. Examples of the substituent when the alicyclic hydrocarbon group is substituted include a methyl group, an ethyl group, and a propyl group.

The linear or branched alkyl group having 1 to 10 carbon atoms represented by R ^B6 preferably has 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms (for example, methyl Group, ethyl group, butyl group, etc.).

The compound represented by the general formula (B) is particularly preferably R ^B1 is a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, and R ^{B2 to} R ^B5 are each independently —CH ₂ —O—. a compound represented by R ^{B6, R B6} is a methyl group or an n- butyl group.

  The compound represented by the general formula (B) is synthesized by, for example, a known method using guanamine and formaldehyde (for example, “Experimental Chemistry Course”, 4th edition, Volume 28, page 430).

  Specific examples of the compound represented by formula (B) are shown below, but are not limited thereto. Moreover, although the following specific examples show a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient.

  Examples of commercially available compounds represented by the general formula (B) include superbecamine (R) L-148-55, superbecamine (R) 13-535, and superbecamine (R) L-145. 60, Superbecamine (R) TD-126 (manufactured by DIC Corporation), Nicarak BL-60, Nicarac BX-4000 (manufactured by Sanwa Chemical Co., Ltd.), and the like.

  The compound represented by the general formula (B) (including multimers) is dissolved in an appropriate solvent such as toluene, xylene or ethyl acetate after synthesis or after purchase of a commercial product in order to remove the influence of residual catalyst. It may be washed with distilled water, ion exchange water or the like, or may be removed by treatment with an ion exchange resin.

-Melamine compounds-
The melamine compound is a compound having a melamine skeleton (structure), and is particularly preferably at least one of a compound represented by the following general formula (C) and a multimer thereof. Here, the multimer is an oligomer polymerized using the compound represented by the general formula (C) as a structural unit, and the degree of polymerization is, for example, 2 or more and 200 or less (desirably 2 or more and 100 or less). The compound represented by the general formula (C) or a multimer thereof may be used alone or in combination of two or more. When the compound represented by the general formula (C) is used as a mixture of two or more kinds, or used as a multimer (oligomer) containing the compound as a structural unit, the solubility in a solvent is improved.

In General Formula (C), R ^{C1 to} R ^C6 each independently represent a hydrogen atom, —CH ₂ —OH, —CH ₂ —O—R ^C7 , or —O—R ^C7 , and R ^C7 represents the number of carbon atoms. 1 or more and 5 or less linear or branched alkyl group is represented. Examples of the alkyl group include a methyl group, an ethyl group, and a butyl group.

  The compound represented by the general formula (C) is synthesized by, for example, a known method (for example, “Experimental Chemistry Course”, 4th edition, Volume 28, page 430) using melamine and formaldehyde.

  Although the specific example of a compound represented by general formula (C) below is shown, it is not necessarily restricted to these. Moreover, although the following specific examples show a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient.

  As a commercial item of the compound represented by the general formula (C), for example, Super Melami No. 90 (manufactured by NOF Corporation), Super Becamine (R) TD-139-60 (manufactured by DIC), Uban 2020 (manufactured by Mitsui Chemicals), Smitex Resin M-3 (manufactured by Sumitomo Chemical Co., Ltd.), Nicarac MW -30 (manufactured by Sanwa Chemical Co., Ltd.).

  The compound represented by the general formula (C) (including multimers) is dissolved in an appropriate solvent such as toluene, xylene or ethyl acetate after synthesis or after purchase of a commercial product in order to remove the influence of residual catalyst. It may be washed with distilled water, ion exchange water or the like, or may be removed by treatment with an ion exchange resin.

When the reactive charge transport material is used as the charge transport material, the total content of the guanamine compound and the melamine compound is desirably 0.1% by mass or more and 10% by mass or less based on the total solid content of the surface protective layer. More preferably, the content is 0.5% by mass or more and 5% by mass or less. When the content is 0.1% by mass or more, the surface protective layer becomes a denser cured film, and the wear resistance of the electrophotographic photosensitive member is further improved. On the other hand, by setting it as 10 mass% or less, the film-forming property is good and the electrical characteristics are further improved.
The content of the guanamine compound and the melamine compound in the surface protective layer is controlled by adjusting the solid content concentration of these compounds in the composition for forming the surface protective layer.
According to the electrophotographic photoreceptor according to the exemplary embodiment, even when the surface protective layer is a cured film containing the guanamine compound and the melamine compound in the above content, the occurrence of dot-like image defects is suppressed.

[Fluorine resin particles]
The fluorine resin particles are not particularly limited. For example, polytetrafluoroethylene (PTFE, also known as “tetrafluoroethylene resin”), perfluoroalkoxy fluorine resin, polychlorotrifluoroethylene, polyvinylidene fluoride, Polydichlorodifluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer Examples thereof include particles of a polymer, a tetrafluoroethylene-perfluoroalkoxyethylene copolymer, and the like.
Among these, polytetrafluoroethylene and a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene are desirable from the viewpoint of wear resistance and cleaning properties of the electrophotographic photosensitive member.
The fluororesin particles may be used alone or in combination of two or more.

The weight average molecular weight of the fluororesin constituting the fluororesin particles is preferably, for example, 3000 or more and 5 million or less.
The average primary particle size of the fluororesin particles is preferably, for example, 0.05 μm or more and 10 μm or less, and more preferably 0.1 μm or more and 5 μm or less.
The average primary particle size of the fluororesin particles is refracted by using a laser diffraction particle size distribution analyzer LA-920 (manufactured by Horiba Seisakusho) to refract the measurement liquid diluted in the same solvent as the dispersion liquid in which the fluororesin particles are dispersed. A value measured at a rate of 1.35.

  Examples of commercially available fluororesin particles include the Lubron series (manufactured by Daikin Industries), the Teflon (registered trademark) series (manufactured by DuPont), the Dinion series (manufactured by Sumitomo 3M), and the like.

  From the viewpoint of adjusting the surface free energy and the ten-point average roughness Rz, the content of the fluororesin particles is desirably 10% by mass or more and 60% by mass or less with respect to the total component of the layer (total solid content). Desirably, it is 20 mass% or more and 50 mass% or less, More desirably, it is 30 mass% or more and 45 mass% or less.

[Fluorinated alkyl group-containing copolymer]
A fluoroalkyl group-containing copolymer may be used in combination with the fluororesin particles as a dispersant. The fluorinated alkyl group-containing copolymer maintains the dispersion stability of the fluororesin particles.
Examples of the fluorinated alkyl group-containing copolymer include fluorinated alkyl group-containing copolymers having repeating units represented by the following structural formula (E) and structural formula (F).

In Structural Formula (E) and Structural Formula (F), R ¹⁰¹ , R ¹⁰² , R ¹⁰³ and R ¹⁰⁴ each independently represent a hydrogen atom or an alkyl group. X ′ represents an alkylene chain, a halogen-substituted alkylene chain, —S—, —O—, —NH—, or a single bond. Y ′ represents an alkylene chain, a halogen-substituted alkylene chain, — (C _z H _2z-1 (OH)) —, or a single bond. However, z represents an integer of 1 or more. Q represents -O- or -NH-. g, h and i each independently represents an integer of 1 or more. p ′, q ′, r ′ and s ′ each independently represent 0 or an integer of 1 or more. t ′ represents an integer of 1 to 7.

Here, the group represented by R ¹⁰¹ , R ¹⁰² , R ¹⁰³ and R ¹⁰⁴ is preferably a hydrogen atom, a methyl group or an ethyl group, and more preferably a methyl group.
The alkylene chain represented by X ′ and Y ′ (unsubstituted alkylene chain, halogen-substituted alkylene chain) is preferably an alkylene chain having 1 to 10 carbon atoms.
Z in — (C _z H _2z-1 (OH)) — represented by Y ′ is preferably an integer of 1 or more and 10 or less.
p ′, q ′, r ′, and s ′ are each independently preferably 0 or an integer of 1-10.

  In the fluorinated alkyl group-containing copolymer, the content ratio of structural formula (E) to structural formula (F), that is, g: h is preferably 1: 9 to 9: 1, and 3: 7 to 7: 3. More desirable.

  The fluorinated alkyl group-containing copolymer may further contain a repeating unit represented by the structural formula (G). The content of the structural formula (G) is preferably 10: 0 to 7: 3 as g + h: j in the ratio of the total content of the structural formula (E) and the structural formula (F), that is, g + h, 9: 1 To 7: 3 is more desirable.

In Structural Formula (G), R ¹⁰⁵ and R ¹⁰⁶ represent a hydrogen atom or an alkyl group. j represents an integer of 1 or more.
The group represented by R ¹⁰⁵ or R ¹⁰⁶ is preferably a hydrogen atom, a methyl group, or an ethyl group, and more preferably a methyl group.

Commercially available fluorinated alkyl group-containing copolymers include, for example, GF300, GF400 (manufactured by Toagosei Co., Ltd.), Surflon series (manufactured by AGC Seikagaku Co., Ltd.), footent series (manufactured by Neos), and PF series (Kitamura). Chemical Co., Ltd.), Mega Fuck Series (DIC), FC Series (3M), and the like.
The fluoroalkyl group-containing copolymer may be used alone or in combination of two or more.

The weight average molecular weight of the fluorinated alkyl group-containing copolymer is, for example, 2000 or more and 250,000 or less, preferably 3000 or more and 150,000 or less, more preferably 10,000 or more and 100,000 or less, and further preferably 30000 or more and 100,000 or less. is there.
The weight average molecular weight of the fluorinated alkyl group-containing copolymer is measured by gel permeation chromatography (GPC).

  The content of the fluorinated alkyl group-containing copolymer is preferably 0.5% by mass or more and 10% by mass or less, and more preferably 1% by mass or more and 7% by mass or less with respect to the mass of the fluororesin particles.

[Surfactant]
The surface protective layer may contain a surfactant for the purpose of adjusting the surface free energy and the ten-point average roughness Rz. As the surfactant, a surfactant containing at least one of a fluorine atom, an alkylene oxide structure, and a silicone structure is desirable, and those having a plurality of the above structures have high affinity / compatibility with the charge transporting organic compound and surface protection. The film forming property of the layer coating liquid is improved, and wrinkles and unevenness of the surface protective layer are suppressed, so that it is preferable.

  Examples of the surfactant having a fluorine atom include a surfactant having a fluorine atom and an acrylic structure. Specifically, Polyflow KL600 (manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF-351, EF-352, EF- 801, EF-802, EF-601 (manufactured by JEMCO).

  In addition, examples of the surfactant having a fluorine atom include surfactants having a perfluoroalkyl group. Specific examples thereof include perfluoroalkyl sulfonic acids (for example, perfluorobutane sulfonic acid, perfluorooctane sulfonic acid). Etc.), perfluoroalkyl carboxylic acids (for example, perfluorobutane carboxylic acid, perfluoro octane carboxylic acid, etc.), and perfluoroalkyl group-containing phosphate esters. Perfluoroalkylsulfonic acids and perfluoroalkylcarboxylic acids may be salts thereof and amide-modified products thereof.

Examples of commercially available products of perfluoroalkyl sulfonic acids include Megafac F-114 (manufactured by DIC), F-top EF-101, EF102, EF-103, EF-104, EF-105, EF-112, and EF-121. , EF-122A, EF-122B, EF-122C, EF-123A (manufactured by JEMCO), AK, 501 (manufactured by Neos) and the like.
Examples of commercially available perfluoroalkyl carboxylic acids include Megafac F-410 (manufactured by DIC Corporation), F-top EF-201, EF-204 (manufactured by JEMCO Corporation), and the like.
Commercially available products of perfluoroalkyl group-containing phosphates include MegaFac F-493, F-494 (above, manufactured by DIC), F-top EF-123A, EF-123B, EF-125M, EF-132 (above. , Manufactured by JEMCO).

  Furthermore, the fluorinated alkyl group-containing copolymer mentioned as the dispersant for the fluororesin particles may also be used as a surfactant for the purpose of adjusting the surface free energy and the ten-point average roughness Rz. Commercially available products include, for example, GF300, GF400 (manufactured by Toagosei Co., Ltd.), Surflon series (manufactured by AGC Seikagaku Co., Ltd.), tangent series (manufactured by Neos Co., Ltd.), PF series (manufactured by Kitamura Chemical Co., Ltd.), MegaFuck series ( DIC), FC series (3M) and the like. These may be included in the surface protective layer, that is, the composition for forming the layer, even when the fluororesin particles are not used.

  The content of the surfactant is desirably 0.01% by mass or more and 1% by mass or less, more desirably 0.02% by mass or more and 0.5% by mass or less with respect to the total solid content of the protective layer.

Hereinafter, the surface protective layer will be described in more detail.
In the surface protective layer, a phenol resin, a urea resin, an alkyd resin, or the like may be used in combination with a reactive charge transport material (for example, a compound represented by the general formula (A)). In order to improve the strength, a compound having a larger number of functional groups in one molecule such as spiroacetal guanamine resin (for example, “CTU-guanamine” manufactured by Ajinomoto Fine Techno Co., Ltd.) It is also effective to copolymerize the material.

  The surface protective layer may be mixed with another thermosetting resin such as a phenol resin for the purpose of effectively suppressing oxidation by the discharge generated gas so that the discharge generated gas is not excessively adsorbed.

An antioxidant may be added to the surface protective layer. The antioxidant is an additive used for the purpose of suppressing deterioration due to an oxidizing gas such as ozone generated in the charging device.
Examples of antioxidants include hindered phenol antioxidants, aromatic amine antioxidants, hindered amine antioxidants, organic sulfur antioxidants, phosphite antioxidants, and dithiocarbamate antioxidants. And known antioxidants such as oxidants, thiourea antioxidants, and benzimidazole antioxidants.

  The surface protective layer may be used by mixing with a coupling agent or a fluorine compound for the purpose of adjusting the film formability, flexibility, lubricity, and adhesion of the film. As this compound, various silane coupling agents and commercially available silicone hard coat agents are used.

For the surface protective layer, alcohol is used for the purpose of discharge gas resistance, mechanical strength, scratch resistance, particle dispersibility, viscosity control, torque reduction, wear amount control, pot life (storability of coating liquid for layer formation), etc. A resin that dissolves in the solution may be added.
Here, the resin that dissolves in alcohol means a resin that dissolves 1% by mass or more in an alcohol having 5 or less carbon atoms. As resin which melt | dissolves in alcohol, polyvinyl acetal resin and polyvinyl phenol resin are mentioned, for example.

Various particles may be added to the surface protective layer for the purpose of lowering the residual potential or improving the strength. An example of the particles is silicon-containing particles. The silicon-containing particles are particles containing silicon as a constituent element, and specific examples include colloidal silica and silicone particles.
An oil such as silicone oil may be added to the surface protective layer for the same purpose.
A metal, metal oxide, carbon black, or the like may be added to the surface protective layer.

  The surface protective layer is preferably a cured film (cross-linked film) obtained by polymerizing (cross-linking) a reactive charge transporting material and, if necessary, a guanamine compound and a melamine compound using an acid catalyst. Acid catalysts include aliphatic carboxylic acids such as acetic acid, chloroacetic acid, trichloroacetic acid, trifluoroacetic acid, oxalic acid, maleic acid, malonic acid, and lactic acid; aromatics such as benzoic acid, phthalic acid, terephthalic acid, and trimellitic acid Carboxylic acids: Aliphatic or aromatic sulfonic acids such as methanesulfonic acid, dodecylsulfonic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, etc. are used, but sulfur-containing materials (especially organic sulfonic acids) And derivatives thereof).

  Here, the blending amount of the catalyst is in the range of 0.1% by mass or more and 50% by mass or less with respect to all the constituent components (solid content) excluding the fluororesin particles and the fluorinated alkyl group-containing copolymer. Is desirable, and 10 mass% or more and 30 mass% or less are especially desirable. When the amount is less than the above range, the catalytic activity may be too low, and when it exceeds the above range, the light resistance may be deteriorated. The light resistance refers to a phenomenon in which the irradiated portion causes a decrease in density when the photosensitive layer is exposed to light from the outside such as room light. The cause is not clear, but it is presumed that a phenomenon similar to the optical memory effect occurs as disclosed in JP-A-5-099737.

  The surface protective layer having the above structure is formed using a coating liquid for forming a surface protective layer in which the above components are mixed. The coating solution for forming the surface protective layer may be prepared without a solvent, or may be performed using a solvent as necessary. Such solvents are used singly or in combination of two or more, and preferably have a boiling point of 100 ° C. or lower. As the solvent, it is particularly preferable to use a solvent having at least one hydroxyl group (for example, alcohol).

  In addition, when a coating solution is obtained by reacting the above components, it may be simply mixed and dissolved, but it is room temperature (for example, 25 ° C.) to 100 ° C., preferably 30 ° C. to 80 ° C., for 10 minutes to 100 Heating may be performed for a period of time or less, preferably 1 hour or more and 50 hours or less. It is also desirable to irradiate ultrasonic waves at this time. Thereby, it is likely that a partial reaction proceeds, and it becomes easy to obtain a film with few coating film defects and little variation in thickness.

  Then, a coating solution for forming the surface protective layer is applied by a known method such as a blade coating method, a Mayer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, a curtain coating method, etc. Accordingly, for example, the surface protective layer is obtained by heating and curing at a temperature of 100 ° C. to 170 ° C. (desirably 140 ° C. to 160 ° C.). The surface free energy and the ten-point average roughness Rz of the surface protective layer can be adjusted by adjusting the heating temperature for the heat curing.

  The film thickness of the surface protective layer is preferably 1 μm or more and 15 μm or less, and more preferably 3 μm or more and 10 μm or less.

The function-separated type electrophotographic photosensitive member has been described above as an example. However, for example, in the case of forming the single-layer type photosensitive layer (charge generation / charge transport layer) shown in FIG. % Or more and about 85 mass% or less are desirable, and more desirably 20 mass% or more and 50 mass% or less. In addition, the content of the charge transport material is desirably 5% by mass or more and 50% by mass or less.
The method for forming the single-layer type photosensitive layer is the same as the method for forming the charge generation layer and the charge transport layer. The thickness of the single-layer type photosensitive layer is preferably about 5 μm to 50 μm, and more preferably 10 μm to 40 μm.

<Image forming apparatus, process cartridge>
FIG. 4 is a schematic configuration diagram illustrating the image forming apparatus according to the present embodiment.
As shown in FIG. 4, the image forming apparatus 101 according to the present embodiment includes, for example, an electrophotographic photosensitive member 10 that rotates clockwise as indicated by an arrow A, and an electronic A charging device 20 (an example of a charging unit) that is provided relative to the photographic photosensitive member 10 and charges the surface of the electrophotographic photosensitive member 10, and the surface of the electrophotographic photosensitive member 10 charged by the charging device 20 is exposed to light. An exposure device 30 (an example of an electrostatic latent image forming unit) that forms an electrostatic latent image, and a toner contained in a developer is attached to the electrostatic latent image formed by the exposure device 30 to form an electrophotographic photosensitive member 10. The developing device 40 (an example of a developing unit) that forms a toner image on the surface and the recording paper P (transfer medium) are charged to a polarity different from the charging polarity of the toner, and the recording paper P is placed on the electrophotographic photoreceptor 10. Transfer device 50 for transferring a toner image , And a cleaning device 70 for cleaning the surface of the electrophotographic photosensitive member 10 (an example of a toner removing means). A fixing device 60 is provided for fixing the toner image while conveying the recording paper P on which the toner image is formed.

  Details of main components in the image forming apparatus 101 according to the present embodiment will be described below.

(Charging device)
As the charging device 20, a contact-type charger that includes a roller-shaped charging member that rotates in contact with the electrophotographic photosensitive member 10 and charges the surface of the electrophotographic photosensitive member 10 with the roller-shaped charging member is applied. .
The roller-shaped charging member is preferably in contact with the photoreceptor at a pressure of 250 mgf or more and 600 mgf or less.

  The electric field applied to the charging member may be a DC electric field or an AC electric field, but is preferably a DC electric field. Although an AC electric field is desirable from the viewpoint that dot-like image quality defects are less likely to occur, the AC electric field may promote deterioration of the surface protective layer of the electrophotographic photosensitive member. In the electrophotographic photosensitive member according to the present embodiment, even when the electric field applied to the charging member is a direct current electric field, dot-like image quality defects are less likely to occur, and therefore, suppression of image quality defects and a long life of the electrophotographic photosensitive member are possible. Is easy to achieve.

The charging member is made of a material adjusted to an electric resistance (for example, 103Ω or more and 108Ω or less) effective as the charging member, and may be made of a single layer or a plurality of layers.
Materials constituting the charging member include urethane rubber, silicone rubber, fluorine rubber, chloroprene rubber, butadiene rubber, EPDM (ethylene-propylene-diene copolymer rubber), epichlorohydrin rubber and other synthetic rubber, polyolefin, polystyrene, vinyl chloride A material obtained by blending an appropriate amount of an optional conductivity imparting agent such as conductive carbon, metal oxide, or ionic conductive agent is used. In addition, a resin such as nylon, polyester, polystyrene, polyurethane, or silicone is made into a paint, and an appropriate amount of any conductivity-imparting agent such as conductive carbon, metal oxide, or ionic conductive agent is blended there, and the resulting paint is immersed. The film may be applied and laminated by any method such as spraying or roll coating.

(Exposure equipment)
Examples of the exposure apparatus 30 include optical system devices that expose the surface of the electrophotographic photoreceptor 10 with light such as semiconductor laser light, LED light, and liquid crystal shutter light imagewise. The wavelength of the light source is preferably within the spectral sensitivity region of the electrophotographic photoreceptor 10. As the wavelength of the semiconductor laser, for example, near infrared having an oscillation wavelength around 780 nm is preferable. However, the present invention is not limited to this wavelength, and a laser having an oscillation wavelength of 600 nm or a laser having an oscillation wavelength of 400 nm to 450 nm as a blue laser may be used. Further, as the exposure apparatus 30, for example, a surface emitting laser light source of a multi-beam output type is also effective for color image formation.

(Developer)
An example of the developing device 40 is a configuration in which a developing roll 41 disposed in the developing region facing the electrophotographic photosensitive member 10 is provided in a container that stores a two-component developer composed of toner and a carrier. The developing device 40 is not particularly limited as long as it is a device that develops with a two-component developer, and a known configuration is employed.

Here, the developer used in the developing device 40 will be described.
The developer may be a one-component developer made of toner, or a two-component developer containing toner and carrier.

  The toner includes, for example, toner particles containing a binder resin, a colorant, and, if necessary, other additives such as a release agent, and external additives as necessary.

The toner particles have an average shape factor (shape factor = (ML ² / A) × (π / 4) × 100), and ML represents the maximum length of the particles, where A represents the maximum length of the particles (Representing the projected area) is preferably from 100 to 150, more preferably from 105 to 145, and even more preferably from 110 to 140. Further, the toner preferably has a volume average particle diameter of 3 μm or more and 12 μm or less, more preferably 3.5 μm or more and 10 μm or less, and further preferably 4 μm or more and 9 μm or less.

  The toner particles are not particularly limited by the production method, and for example, a kneading and pulverizing method in which a binder resin, a colorant and a release agent, and a charge control agent and the like are added, if necessary, are kneaded, pulverized, and classified; A method of changing the shape of the particles obtained by the kneading and pulverization method by mechanical impact force or thermal energy; the polymerization monomer of the binder resin is emulsion-polymerized, the formed dispersion, the colorant and the release agent Emulsion polymerization aggregation method to obtain a toner particle by mixing a mold agent and, if necessary, a dispersion of a charge control agent, and agglomerating and heat-fusing; a polymerizable monomer for obtaining a binder resin, and coloring Suspension polymerization method in which a solution of an agent, a release agent and, if necessary, a charge control agent is suspended in an aqueous solvent for polymerization; a binder resin, a colorant and a release agent, and if necessary, a charge control agent Toner particles produced by a solution suspension method in which a solution such as a liquid is suspended in an aqueous solvent and granulated There will be used.

  Further, a known method such as a production method in which the toner particles obtained by the above method are used as a core, and agglomerated particles are further adhered and heated and fused to give a core-shell structure is used. The toner production method is preferably a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method in which an aqueous solvent is used from the viewpoint of shape control and particle size distribution control, and an emulsion polymerization aggregation method is particularly desirable.

  The toner is produced by mixing the toner particles and the external additive with a Henschel mixer or a V blender. Further, when the toner particles are produced by a wet method, they may be externally added by a wet method.

  When the toner is used as a two-component developer, the mixing ratio with the carrier is set at a known ratio. In addition, there is no restriction | limiting in particular as a carrier, For example, what carried out resin coating to the surface of a magnetic particle as a carrier is mentioned suitably.

(Transfer device)
As the transfer device 50, for example, a contact transfer charger using a belt, a roller, a film, a rubber blade or the like, or a known transfer charger such as a scorotron transfer charger using a corona discharge or a corotron transfer charger. Can be mentioned.

(Cleaning device)
The cleaning device 70 includes, for example, a casing 71, a cleaning blade 72, and a cleaning brush 73 disposed on the downstream side of the cleaning blade 72 in the rotation direction of the electrophotographic photosensitive member 10. Further, for example, a solid lubricant 74 is disposed in contact with the cleaning brush 73.

  Hereinafter, the operation of the image forming apparatus 101 according to the present embodiment will be described. First, the electrophotographic photoreceptor 10 rotates along the direction represented by the arrow A, and at the same time, is negatively charged by the charging device 20.

  The electrophotographic photoreceptor 10 whose surface is negatively charged by the charging device 20 is exposed by the exposure device 30, and a latent image is formed on the surface.

  When the portion where the latent image is formed on the electrophotographic photosensitive member 10 approaches the developing device 40, toner is attached to the latent image by the developing device 40 (developing roll 41), and a toner image is formed.

  When the electrophotographic photosensitive member 10 on which the toner image is formed further rotates in the direction of arrow A, the toner image is transferred onto the recording paper P by the transfer device 50. As a result, a toner image is formed on the recording paper P.

  The toner image is fixed on the recording paper P on which the image is formed by the fixing device 60.

For example, as illustrated in FIG. 5, the image forming apparatus 101 according to the present embodiment includes an electrophotographic photosensitive member 10, a charging device 20, an exposure device 30, a developing device 40, and a cleaning device 70 in a housing 11. May be provided with a process cartridge 101 </ b> A in which are integrally stored. The process cartridge 101A integrally contains a plurality of members and is attached to and detached from the image forming apparatus 101.
The configuration of the process cartridge 101A is not limited to this. For example, the process cartridge 101A only needs to include at least the electrophotographic photosensitive member 10 and the charging device 20, and for example, the exposure device 30, the developing device 40, the transfer device 50, and the like. At least one selected from the cleaning device 70 may be provided.

  In addition, the image forming apparatus 101 according to the present embodiment is not limited to the above configuration, and is, for example, a cleaning device around the electrophotographic photosensitive member 10 and downstream of the transfer device 50 in the rotation direction of the electrophotographic photosensitive member 10. A first neutralization device may be provided on the upstream side of the rotation direction of the electrophotographic photosensitive member from 70 so that the polarity of the remaining toner is aligned and easy to remove with a cleaning brush. Alternatively, a configuration may be adopted in which a second static elimination device for neutralizing the surface of the electrophotographic photosensitive member 10 is provided on the downstream side in the rotation direction of the electrophotographic photosensitive member and on the upstream side in the rotational direction of the electrophotographic photosensitive member relative to the charging device 20. .

  The image forming apparatus 101 according to the present embodiment is not limited to the above-described configuration, and a known configuration, for example, a toner image formed on the electrophotographic photosensitive member 10 is transferred to the intermediate transfer member and then transferred to the recording paper P. An intermediate transfer type image forming apparatus or a tandem type image forming apparatus may be used.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Example 19 is shown as a reference example.
In the following, “part” is based on mass unless otherwise specified.

<Example 1>
[Formation of undercoat layer]
100 parts of zinc oxide (manufactured by Teika, average particle size 70 nm, specific surface area value 15 m ² / g) is stirred and mixed with 500 parts of tetrahydrofuran, and 1.25 parts of a silane coupling agent (KBM603, Shin-Etsu Chemical Co., Ltd.) is added. Stir for 2 hours. Tetrahydrofuran was then distilled off under reduced pressure and baked at 120 ° C. for 3 hours to obtain zinc oxide surface-treated with a silane coupling agent.
60 parts of this surface-treated zinc oxide, 0.5 part of alizarin (manufactured by Nagase Sangyo), which is an electron accepting substance, 13.5 parts of a curing agent (blocked isocyanate, Sumidur 3173, manufactured by Sumitomo Bayern Urethane Co., Ltd.), butyral resin (Sekisui Chemical Co., Ltd. ESREC BM-1) 10 parts mixed with methyl ethyl ketone 72 parts and n-hexane 18 parts, 57 parts of a mixture using glass beads having a diameter of 1 mm for 2 hours, A dispersion was obtained.
To this dispersion, 0.005 part of dioctyltin dilaurate and 4.0 parts of silicone resin particles (Tospearl 145 manufactured by GE Toshiba Silicone) were added as a catalyst to obtain a coating liquid for forming an undercoat layer.
This undercoat layer forming coating solution is applied on an aluminum substrate having a diameter of 60 mm, a length of 357 mm, and a thickness of 1 mm by a dip coating method, followed by drying and curing at 170 ° C. for 40 minutes, and a thickness of 25 μm. An undercoat layer was formed.

[Formation of charge generation layer]
Hydroxygallium having diffraction peaks at X-ray diffraction spectrum Bragg angles (2θ ± 0.2 °) of at least 7.3 °, 16.0 °, 24.9 ° and 28.0 ° using CuKα rays 15 parts of phthalocyanine, 10 parts of vinyl chloride / vinyl acetate copolymer resin (VMCH manufactured by Nihon Unicar Co., Ltd.) and 200 parts of n-butyl acetate as a binder resin are mixed and put into a sand mill using glass beads having a diameter of 1 mm. For 4 hours to obtain a dispersion. To this dispersion, 175 parts of n-butyl acetate and 180 parts of methyl ethyl ketone were added and stirred to obtain a charge generation layer forming coating solution. This charge generation layer forming coating solution was dip coated on the undercoat layer and dried at a temperature of 24 ° C. (± 1 ° C.) to form a charge generation layer having a thickness of 0.2 μm.

[Formation of charge transport layer]
4 parts of N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1 ′] biphenyl-4,4′-diamine, which is a charge transport material, and bisphenol Z-type polycarbonate resin (viscosity 6 parts of average molecular weight 50000) is mixed and dissolved in 23 parts of tetrahydrofuran and 10 parts of toluene, and then 0.2 part of 2,6-di-t-butyl-4-methylphenol is mixed to form a charge transport layer. A coating solution was obtained. This charge transport layer forming coating solution was dip coated on the charge generation layer and dried by heating at 115 ° C. for 40 minutes to form a charge transport layer having a thickness of 22 μm.

[Formation of surface protective layer]
9.7 parts of the compound (1) represented by the following formula, 35 parts of cyclopentanol, 9 parts of tetrahydrofuran, and 0.9 part of distilled water were mixed to obtain an ion exchange resin (Amberlyst 15E manufactured by Rohm and Haas). ) 0.5 part was added, and the mixture was stirred at a temperature of 24 ° C. (± 1 ° C.) for 2 hours for hydrolysis, and then the ion exchange resin was filtered off.
Subsequently, 0.15 part of benzoguanamine resin (Nikalac BL-60 manufactured by Sanwa Chemical Co., Ltd .; multimer of (B) -17 described above) was added to the filtered solution to prepare a mixed solution A.

  Next, 8 parts (average particle diameter 0.2 μm) of tetrafluoroethylene resin (PTFE) particles, alkyl fluoride containing repeating units represented by the following structural formula (E) -1 and structural formula (F) -1 A group-containing copolymer (weight average molecular weight 30000, 1: m = 1: 1, s = 1, n = 60) 0.01 part, 16 parts of cyclopentanol and 4 parts of tetrahydrofuran are mixed, and a liquid at 20 ° C. While maintaining the temperature, the mixture was stirred and mixed for 48 hours to obtain a resin particle suspension B.

Next, after adding the resin particle suspension B to the mixed solution A and stirring and mixing, 500 kgf / cm using a high-pressure homogenizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.) equipped with a through-type chamber having fine flow paths. The dispersion process with the pressure increased to ² was repeated 6 times. Subsequently, 650 ppm of Polyflow KL600 (fluorine surfactant, manufactured by Kyoei Chemical Co., Ltd.) was added and stirred sufficiently to obtain a coating solution for forming a surface protective layer. This coating solution for forming the surface protective layer was dip coated on the charge transport layer to form a coating film, and this coating film was dried by heating at 155 ° C. for 45 minutes to form a surface protective layer having a thickness of 7 μm.
Thus, an electrophotographic photosensitive member of Example 1 was obtained.

<Example 2 and Example 3>
The electrophotographic photoreceptors of Example 2 and Example 3 were prepared in the same manner as in Example 1 except that the temperature at which the coating film for forming the surface protective layer was heated and dried was changed to the temperature shown in Table 1. Produced.

<Example 4>
An electrophotographic photosensitive member of Example 4 was produced in the same manner as in Example 1 except that Polyflow KL600 was changed to Surflon S651 (fluorine surfactant, manufactured by AGC Seikagaku Co.).

<Example 5 and Example 6>
Example 5 and Example 5 were carried out in the same manner as Example 1 except that Polyflow KL600 was changed to Surflon S651 and the temperature at which the coating film of the coating solution for forming the surface protective layer was dried by heating was changed to the temperature shown in Table 1. Each electrophotographic photoreceptor of Example 6 was prepared.

<Example 7 to Example 9>
The electrophotographic photoreceptors of Examples 7 to 9 were prepared in the same manner as in Example 1 except that the temperature at which the coating film for forming the surface protective layer was heated and dried was changed to the temperature shown in Table 1. Produced.

<Example 10>
The benzoguanamine resin (Nicarak BL-60) was changed to a methylated melamine resin (Nikalac MW-30HM manufactured by Sanwa Chemical Co., Ltd .; the multimer of (C) -2 described above), and the polyflow KL600 was changed to Surflon S651. In the same manner as in Example 1, an electrophotographic photoreceptor of Example 10 was produced.

<Example 11>
An electrophotographic photosensitive member of Example 11 was produced in the same manner as in Example 1 except that the compound (1) was changed to the compound (2) represented by the following formula and that the polyflow KL600 was changed to Surflon S651.

<Example 12>
An electrophotographic photosensitive member of Example 12 was produced in the same manner as in Example 1 except that Compound (1) was changed to Compound (3) represented by the following formula and Polyflow KL600 was changed to Surflon S651.

<Example 13>
Except for changing the compound (1) to the compound (4) represented by the following formula, changing Nicarak BL-60 to Nicalac MW-30HM, and changing Polyflow KL600 to Surflon S651, the same as in Example 1, The electrophotographic photosensitive member of Example 13 was produced.

<Example 14>
Compound (1) was changed to Compound (5) represented by the following formula, Nicalak BL-60 was changed to Nicalak MW-30HM, and Polyflow KL600 was changed to Surflon S651. The electrophotographic photosensitive member of Example 14 was produced.

<Example 15>
9.7 parts of the compound (6) represented by the following formula, 35 parts of cyclopentanol, 9 parts of tetrahydrofuran and 0.9 part of distilled water are mixed, and 0.5 part of ion exchange resin (Amberlyst 15E) is added. After hydrolysis for 2 hours at a temperature of 24 ° C. (± 1 ° C.), the ion exchange resin was filtered off.
Subsequently, 0.15 part of methylated melamine resin (Nicalac MW-30HM) was added to the liquid separated by filtration to prepare a mixed solution B.

Next, a resin particle suspension B was obtained in the same manner as in Example 1.
Next, after adding the resin particle suspension B to the mixed solution B and stirring and mixing, 500 kgf / cm using a high-pressure homogenizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.) equipped with a through-type chamber having fine flow paths. The dispersion process with the pressure increased to ² was repeated 6 times. Then, 650 ppm of Surflon S651 was added and stirred sufficiently to obtain a coating solution for forming a surface protective layer. This coating solution for forming the surface protective layer was dip coated on the charge transport layer to form a coating film, and this coating film was dried by heating at 155 ° C. for 45 minutes to form a surface protective layer having a thickness of 7 μm.
Thus, an electrophotographic photosensitive member of Example 15 was obtained.

<Example 16>
9.7 parts of compound (7) (4,4′-dimethyltriphenylamine) represented by the following formula, 0.25 part of compound (8) represented by the following formula, 35 parts of cyclopentanol, 9 parts of tetrahydrofuran , And 0.9 parts of distilled water were added, 0.5 parts of ion exchange resin (Amberlyst 15E) was added, and the mixture was stirred at a temperature of 24 ° C. (± 1 ° C.) for 2 hours for hydrolysis. The exchange resin was filtered off.
Subsequently, 0.15 part of methylated melamine resin (Nicalac MW-30HM) was added to the filtered solution to prepare a mixed solution C.
An electrophotographic photosensitive member of Example 16 was produced in the same manner as in Example 1 except that this mixed solution C was used instead of the mixed solution A.

<Example 17>
An electrophotographic photoreceptor of Example 17 was produced in the same manner as in Example 1 except that 0.25 part of Compound (8) was used together with Compound (1), and Polyflow KL600 was changed to Surflon S651.

<Example 18>
An electrophotographic photoreceptor of Example 18 was produced in the same manner as in Example 1 except that 0.4 part of Compound (8) was used together with Compound (1), and Polyflow KL600 was changed to Surflon S651.

<Example 19>
An electrophotographic photoreceptor of Example 19 was produced in the same manner as in Example 1 except that the mixed solution A was used as the coating solution for forming the surface protective layer.

<Comparative Example 1 and Comparative Example 2>
Comparative Example 1 and Comparative Example 2 were carried out in the same manner as in Example 1 except that Polyflow KL600 was not used and the temperature at which the coating film of the surface protective layer forming coating solution was dried by heating was changed to the temperature shown in Table 1. An electrophotographic photoreceptor was prepared.

<Comparative Example 3>
An electrophotographic photoreceptor of Comparative Example 3 was produced in the same manner as in Example 1 except that the temperature at which the coating film of the coating solution for forming the surface protective layer was dried by heating was changed to the temperature shown in Table 1.

<Comparative Example 4>
The electrophotographic photosensitive film of Comparative Example 4 was prepared in the same manner as in Example 1 except that Polyflow KL600 was not used and the temperature at which the coating film of the surface protective layer forming coating solution was dried by heating was changed to the temperature shown in Table 1. The body was made.

<Comparative Example 5 and Comparative Example 6>
Example except that Nicarak BL-60 was changed to Nicarak MW-30HM, the temperature at which the coating film of the coating solution for forming the surface protective layer was dried by heating was changed to the temperature shown in Table 1 without using Polyflow KL600. In the same manner as in Example 1, electrophotographic photoreceptors of Comparative Example 5 and Comparative Example 6 were produced.

<Comparative Example 7>
An electrophotographic photoreceptor of Comparative Example 7 was produced in the same manner as in Example 1 except that a solution obtained by adding 650 ppm of Polyflow KL600 to the mixed solution A was used as the coating solution for forming the surface protective layer.

<Comparative Example 8 and Comparative Example 9>
A solution obtained by adding 650 ppm of Surflon S651 to the mixed solution A was used as the coating solution for forming the surface protective layer, and the temperature when the coating film of the coating solution for forming the surface protective layer was dried by heating was changed to the temperature shown in Table 1. In the same manner as in Example 1, the electrophotographic photoreceptors of Comparative Example 8 and Comparative Example 9 were produced.

<Comparative Example 10>
The mixed solution A was used as the coating solution for forming the surface protective layer, and the same procedure as in Example 1 was carried out except that the temperature when the coating film of the coating solution for forming the surface protective layer was dried by heating was changed to the temperature shown in Table 1. An electrophotographic photosensitive member of Comparative Example 10 was produced.

<Comparative Example 11>
An electrophotographic photoreceptor of Comparative Example 11 was produced in the same manner as in Example 1 except that the surface protective layer was not formed.

<Measurement of surface protective layer properties>
The surface free energy and 10-point average roughness Rz of the surface protective layer of each unused photoreceptor were measured by the following methods. The results are shown in Table 1.

(Surface free energy)
Using a contact angle meter (CA-X manufactured by Kyowa Interface Co., Ltd.), the contact angle between the photoreceptor surface and the reagent (methylene iodide, α-bromonaphthalene, water) was measured. The contact angle was measured after placing the photoreceptor in an environment of temperature 23 ° C. (± 1 ° C.) / Relative humidity 55% (± 5%) for 24 hours or more. The reagent droplet was 2.5 μL, and the contact angle 60 seconds after the reagent was dropped on the surface of the photoreceptor was measured. The contact angle is measured at four points in the circumferential direction (4 points of 0 °, 90 °, 180 °, and 270 ° are arbitrarily set as the base point) and four points in the axial direction (position 30 mm from one end). 4 points at a 100 mm pitch), a total of 16 points were measured, and an average value of 16 points was obtained.
Then, surface free energy was obtained from the contact angle value by applying the extended Fowkes theory (specifically, using surface free energy analysis software EG-11 (manufactured by Kyowa Interface Co., Ltd.)).

(10-point average roughness Rz)
Ten-point average roughness Rz (JIS B 0601-1994) was measured using a laser microscope Vk-9500 (manufactured by Keyence Corporation) in the range of 150 μm in the axial direction of the surface of the surface protective layer × 110 μm in the circumferential direction.

<Evaluation>
Each of the photoconductors of Examples and Comparative Examples is mounted on 700 Digital Color Press (equipped with a charging device having a roller-shaped charging member that rotates in contact with the photoconductor) manufactured by Fuji Xerox Co., Ltd., and the following evaluation is performed. It was. An image was formed by applying a DC electric field to the charging member using an evaluation machine equipped with an unused photoreceptor for each evaluation. The results are shown in Table 1.

(Initial image quality)
In an environment of 10 ° C./15 RH%, an A3 halftone image having an image density Cin (Coverage Input) of 20% was output. The image was enlarged and observed, and the number of dot-like image defects (white spots) of 50 μm or more was counted and evaluated according to the following criteria.
A: 0 pieces B: 1 piece or more and 5 pieces or less C: 6 pieces or more and 20 pieces or less D: 21 pieces or more

(Image quality after 100,000 rotations)
Under an environment of 10 ° C./15 RH%, an image with an image density Cin of 100% was output until the photoconductor rotated 100,000 times (within 1% error), and subsequently an A3 halftone image with an image density of Cin 20% was output. The halftone image was enlarged and observed, and the number of dot-like image defects (white spots) of 50 μm or more was counted and evaluated according to the following criteria. “-” In Table 1 means a case where an output of 100,000 rotations could not be made.
A: 0 pieces B: 1 piece or more and 5 pieces or less C: 6 pieces or more and 20 pieces or less D: 21 pieces or more

(Abrasion resistance)
After continuous output of 10,000 random charts with an image density Cin of 5% in an environment of 22 ° C./55 RH%, the film thickness of the photoconductor is measured using an eddy current film thickness measuring device (Fischer Instruments). The difference (μm) from the previously measured film thickness of the photoreceptor was obtained and used as an index of wear resistance. When the continuous output of 10,000 sheets could not be performed due to turning of the cleaning blade or the like, it was determined that “evaluation was impossible”.

  From the results shown in Table 1, it can be seen that in this example, the occurrence of point defects in the image was suppressed as compared with the comparative example.

DESCRIPTION OF SYMBOLS 1 Undercoat layer, 2 Charge generation layer, 3 Charge transport layer, 4 Conductive support body, 5 Surface protective layer, 6 Single layer type photosensitive layer, 10 Electrophotographic photoreceptor, 11 Case, 20 Charging device, 30 Exposure device , 40 Developing device, 41 Developing roll, 50 Transfer device, 60 Fixing device, 70 Cleaning device, 71 Housing, 72 Cleaning blade, 73 Cleaning brush, 74 Lubricant, 101A Process cartridge, 101 Image forming device

Claims (4)

A conductive substrate;
A photosensitive layer provided on the conductive substrate;
Wherein a photosensitive layer surface protective layer provided on, viewed contains a charge transport material, and at least one selected from compounds having the compound and melamine structure having a guanamine structure and a fluorine resin particles, the guanamine structure The total content of the compound having a melamine structure and the compound having the melamine structure is 0.1% by mass or more and 10% by mass or less with respect to the total solid content, and the content of the fluororesin particles is 30% with respect to the total solid content. A surface protective layer having a surface free energy of 45 mN / m or more and 95 mN / m or less.
An electrophotographic photosensitive member having:   The electrophotographic photosensitive member according to claim 1, wherein the surface of the surface protective layer has a ten-point average roughness Rz (JIS B 0601-1994) of 0.3 μm or more and 0.7 μm or less. The electrophotographic photosensitive member according to claim 1 or 2,
A charging device comprising a roller-shaped charging member that rotates in contact with the electrophotographic photosensitive member, and charging the surface of the electrophotographic photosensitive member with the roller-shaped charging member;
An electrostatic latent image forming apparatus for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member;
A developing device for developing the electrostatic latent image with a developer to form a toner image;
A transfer device for transferring the toner image to a transfer medium;
An image forming apparatus. The electrophotographic photosensitive member according to claim 1 or 2,
A charging device comprising a roller-shaped charging member that rotates in contact with the electrophotographic photosensitive member, and charging the surface of the electrophotographic photosensitive member with the roller-shaped charging member;
And a process cartridge that is detachably attached to the image forming apparatus.