JP2016200838A - Hydrophobization-processed silica particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide silica particles that have reduced a silanol group in silica particles.SOLUTION: There are provided hydrophobization-processed silica particles having a volume average particle diameter of 20 nm or more and 200 nm or less and a condensation ratio of 90% or more.SELECTED DRAWING: None

Description

  The present invention relates to hydrophobized silica particles.

The electrophotographic method is widely used for copying machines, printers, and the like.
In recent years, regarding an electrophotographic photosensitive member (hereinafter sometimes referred to as “photosensitive member”) used in an image forming apparatus utilizing electrophotography, a surface layer (protective layer) is provided on the surface of the photosensitive layer of the photosensitive member. Technology is being considered.

  For example, a hard film such as diamond-like carbon (DLC), amorphous carbon nitride (CN), amorphous silicon nitride, aluminum oxide, or gallium oxide is known as the surface layer of the photoreceptor ( For example, see Patent Literature 1 to Patent Literature 5).

  Further, an organic photoreceptor having at least a photosensitive layer on a conductive support has a surface layer containing inorganic particles having a number average primary particle size of 3 to 150 nm, and a surface roughness Ra of 0.001 to 0.00. An organic photoreceptor having a ten-point surface roughness Rz of 0.02 to 0.08 μm is known (for example, see Patent Document 6).

  Further, the photosensitive layer provided directly on the conductive support or via the undercoat layer contains at least a charge generating substance, a charge transporting substance, and an inorganic filler whose crystal structure is a hexagonal close-packed lattice, and such a photosensitive layer An electrophotographic photosensitive member having a large content on the surface side where the inorganic filler is farthest from the conductive support side is known (see, for example, Patent Document 7).

  Also known is an electrophotographic photoreceptor in which the protective layer is composed of a roughness layer containing particles having a number average particle diameter of 5 to 200 nm and a deposited layer having a hardness measured by the nanoindentation method of 2 to 7 GPa. (For example, refer to Patent Document 7).

JP-A-2-110470 JP 2003-27238 A Japanese Patent Laid-Open No. 11-186571 JP 2006-267507 A JP 2008-268266 A JP 2006-010921 A JP 2003-098700 A JP 2009-204922 A

  The subject of this invention is providing the silica particle in which the silanol group of the silica particle was reduced.

The above problem is solved by the following means. That is,
The invention according to claim 1
Hydrophobized silica particles having a volume average particle size of 20 nm to 200 nm and a condensation rate of 90% or more.

The invention according to claim 2
The hydrophobized silica particles according to claim 1, wherein the hydrophobized silica particles have a volume resistivity of 10 ¹¹ Ω · cm or more.
The invention according to claim 3
The hydrophobized silica particle according to claim 1 or 2, wherein the hydrophobized silica particle is a silane compound having a trimethylsilyl group, a decylsilyl group, or a phenylsilyl group on the surface of the silica particle.

  According to the invention which concerns on Claims 1-3, the silica particle in which the silanol group of the silica particle was reduced is provided.

FIG. 3 is a schematic cross-sectional view illustrating an example of a layer configuration of the electrophotographic photosensitive member of the present embodiment. It is a schematic cross section showing another example of the layer configuration of the electrophotographic photosensitive member of the present embodiment. It is a schematic cross section showing another example of the layer configuration of the electrophotographic photosensitive member of the present embodiment. It is a schematic diagram showing an example of a film forming apparatus used for forming the inorganic protective layer of the electrophotographic photosensitive member of the present embodiment. It is a schematic diagram which shows the example of the plasma generator used for formation of the inorganic protective layer of the electrophotographic photoreceptor of this embodiment. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows another example of the image forming apparatus which concerns on this embodiment. FIG.

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

(Electrophotographic photoreceptor)
The electrophotographic photoreceptor according to the exemplary embodiment includes a conductive substrate, an organic photosensitive layer provided on the conductive substrate, and an inorganic protective layer provided on the organic photosensitive layer in contact with the surface thereof.
The organic photosensitive layer is configured to include at least a charge transport material and silica particles in a region on the side in contact with the inorganic protective layer.
Specifically, when the organic photosensitive layer is a single-layer type organic photosensitive layer, the organic photosensitive layer is an organic photosensitive layer configured to include at least a charge generation layer, a charge transport material, and silica particles.
On the other hand, when the organic photosensitive layer is a function-separated type organic photosensitive layer, the organic photosensitive layer has a charge generation layer and a charge transport layer containing at least a charge transport material and silica particles in this order on the conductive substrate. It is an organic photosensitive layer. However, when the charge transport layer is composed of two or more layers, the charge transport layer of the layer (uppermost layer) constituting the surface in contact with the inorganic protective layer contains at least a charge transport material and silica particles. The charge transport layer, which is a lower layer thereof, does not include silica particles and includes at least a charge transport material.

Here, conventionally, a technique for forming an inorganic protective layer on an organic photosensitive layer so as to be in contact with the surface thereof is known.
However, while the organic photosensitive layer has flexibility and tends to be deformed, the inorganic protective layer tends to be inferior in toughness although it is hard. For this reason, when the organic photosensitive layer used as a base layer of an inorganic protective layer deform | transforms, a crack may arise in an inorganic protective layer. Since the electrophotographic photosensitive member is easily mechanically loaded from a member (for example, an intermediate transfer member) disposed in contact with the surface of the electrophotographic photosensitive member, such a phenomenon is likely to occur.

  Therefore, in the present embodiment, the organic photosensitive layer is configured to include at least a charge transport material and silica particles in a region on the side in contact with the inorganic protective layer. Thereby, it is considered that the silica particles function as a reinforcing material for the organic photosensitive layer, and the organic photosensitive layer is hardly deformed at least in the region on the surface side in contact with the inorganic protective layer serving as the base of the inorganic protective layer. For this reason, it is thought that the crack of an inorganic protective layer is suppressed.

On the other hand, when inorganic particles such as a reinforcing material are present in the organic photosensitive layer, the inorganic particles become charge storage sites (trap sites) that generate a residual potential, and it is considered that the residual potential is easily generated.
However, it is considered that silica particles have a lower dielectric constant than other inorganic particles and are unlikely to become charge storage sites (trap sites) that generate a residual potential. For this reason, it is thought that generation | occurrence | production of a residual potential is also suppressed.

As described above, in the electrophotographic photosensitive member according to the present embodiment, the above configuration suppresses the cracking of the inorganic protective layer and the generation of the residual potential.
Further, in the electrophotographic photoreceptor according to the exemplary embodiment, since the silica particles have a lower refractive index than other inorganic particles, it is easy to ensure the transparency of the organic photosensitive layer, and the organic photosensitive layer is obtained by blending the silica particles. There is also an advantage that a decrease in electrical characteristics due to a decrease in transparency is easily suppressed.

Hereinafter, the electrophotographic photoreceptor according to the exemplary embodiment will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.
FIG. 1 is a schematic cross-sectional view showing an example of an electrophotographic photoreceptor according to this embodiment. 2 to 3 are schematic sectional views showing other examples of the electrophotographic photosensitive member according to this embodiment.

An electrophotographic photoreceptor 7A shown in FIG. 1 is a so-called function-separated photoreceptor (or laminated photoreceptor), and an undercoat layer 1 is provided on a conductive substrate 4, on which a charge generation layer 2 and a charge are formed. The transport layer 3 and the inorganic protective layer 5 have a structure formed in order. In the electrophotographic photoreceptor 7A, an organic photosensitive layer is constituted by the charge generation layer 2 and the charge transport layer 3.
The charge transport layer 3 includes at least a charge transport material and silica particles.

  The electrophotographic photoreceptor 7B shown in FIG. 2 has a function separated into the charge generation layer 2 and the charge transport layer 3 as in the electrophotographic photoreceptor 7A shown in FIG. It is a separation type photoreceptor. 3 includes the charge generation material and the charge transport material in the same layer (single layer type organic photosensitive layer 6 (charge generation / charge transport layer)).

In the electrophotographic photoreceptor 7B shown in FIG. 2, an undercoat layer 1 is provided on a conductive substrate 4, and a charge generation layer 2, a charge transport layer 3B, a charge transport layer 3A, and an inorganic protective layer 5 are formed thereon. It has a structure formed sequentially. In the electrophotographic photoreceptor 7B, an organic photosensitive layer is constituted by the charge transport layer 3A, the charge transport layer 3B, and the charge generation layer 2.
The charge transport layer 3A includes at least a charge transport material and silica particles. On the other hand, the charge transport layer 3B does not include silica particles, and includes at least a charge transport material.

The electrophotographic photoreceptor 7C shown in FIG. 3 has a structure in which an undercoat layer 1 is provided on a conductive substrate 4, and a single-layer type organic photosensitive layer 6 and an inorganic protective layer 5 are sequentially formed thereon. It is.
The single-layer type organic photosensitive layer 6 includes at least a charge generation material, a charge transport material, and silica particles.

  In the electrophotographic photoreceptor shown in FIGS. 1 to 3, the undercoat layer 1 may or may not be provided.

  Hereinafter, each element will be described based on the electrophotographic photosensitive member 7A shown in FIG. 1 as a representative example.

-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.
Note that the conductive substrate preferably has a conductivity of, for example, a volume resistivity of less than 10 ⁷ Ω · cm.

  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 organic 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 transporting group Examples thereof include charge transporting resins having a conductive resin 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 silicone 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 set within a range in which 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. You may mix and use 2 or more types of electroconductive particle.
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.

  The formation of the undercoat layer is not particularly limited, and a well-known formation method is used. For example, a coating film of a coating solution for forming an undercoat layer in which the above components are added to a solvent is formed, and the coating film is dried. This is done by heating as necessary.

  Examples of the method for applying the coating solution for forming the undercoat layer on the conductive substrate include dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, curtain coating, and the like. Is mentioned.

  In the case of dispersing the particles in the coating solution for forming the undercoat layer, the dispersion method may be, for example, 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, or the like. Medialess dispersers such as roll mills and high-pressure homogenizers 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. Can be mentioned.

  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 organic photosensitive layer. As the binder resin used for the intermediate layer, acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl In addition to polymer resins such as acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin, zirconium, titanium, aluminum, manganese, silicon atom, etc. An organometallic compound containing 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.

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

  Examples of the method for applying the intermediate layer forming coating solution onto the undercoat layer include dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, and curtain coating. Conventional methods 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, leading to increased desensitization and potential increase due to repetition. It may happen. 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. Note that the charge generation layer may be formed of, for example, a vapor generation film of a charge generation material.

  Examples of the charge generation material include phthalocyanine pigments such as metal-free phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, dichlorotin phthalocyanine, and titanyl phthalocyanine, and in particular, have a Bragg angle (2θ ± 0.2 °) with respect to CuKα characteristic X-rays. Chlorogallium phthalocyanine crystal having strong diffraction peaks at least at 7.4 °, 16.6 °, 25.5 ° and 28.3 °, Bragg angle (2θ ± 0.2 °) to CuKα characteristic X-ray of at least 7. Metal-free phthalocyanine crystals having strong diffraction peaks at 7 °, 9.3 °, 16.9 °, 17.5 °, 22.4 ° and 28.8 °, Bragg angle (2θ ± 0. 2 °) at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25 Hydroxygallium phthalocyanine crystals having strong diffraction peaks at 1 ° and 28.3 °, Bragg angles (2θ ± 0.2 °) with respect to CuKα characteristic X-rays of at least 9.6 °, 24.1 ° and 27.2 ° A titanyl phthalocyanine crystal having a strong diffraction peak 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.

  The formation of the charge generation layer is not particularly limited, and a known formation method is used. For example, a coating film of a charge generation layer forming coating solution in which the above components are added to a solvent is formed, and the coating film is dried. This is done by heating as necessary. The charge generation layer may be formed by vapor deposition of a charge generation material.

  Examples of the method for applying the charge generation layer forming coating liquid on the undercoat layer (or on the intermediate layer) include dip coating, push-up coating, wire bar coating, spray coating, blade coating, and knife coating. Method, curtain coating method and the like.

  In addition, as a method of dispersing particles (for example, charge generation material) in the coating solution for forming the charge generation layer, for example, a media dispersion machine such as a ball mill, a vibration ball mill, an attritor, a sand mill, a horizontal sand mill, agitation, ultrasonic Medialess dispersers such as dispersers, roll mills, and high-pressure homogenizers are used. Examples of the high-pressure homogenizer include a collision method in which a 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.

  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-
-Composition of charge transport layer The charge transport layer comprises a charge transport material, silica particles, 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, tris [4- (4,4-diphenyl-1,3-butadienyl) Aromatic tertiary amino compounds such as phenyl] amine, N, N'-bis (3,4-dimethylphenyl) biphenyl-4-amine, tri (p-methylphenyl) aminyl-4-amine, dibenzylaniline Aromatic tertiary diamino compounds such as N, N′-bis (3-methylphenyl) -N, N′-diphenylbenzidine, 3- (4′-di) 1,2,4-triazine derivatives such as (tilaminophenyl) -5,6-di- (4'-methoxyphenyl) -1,2,4-triazine, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, etc. Hydrazone derivatives, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, benzofuran derivatives such as 6-hydroxy-2,3-di (p-methoxyphenyl) benzofuran, p- (2,2-diphenylvinyl) -N Α-stilbene derivatives such as N-diphenylaniline, enamine derivatives, carbazole derivatives such as N-ethylcarbazole, hole transport materials such as poly-N-vinylcarbazole and its derivatives, quinone compounds such as chloranil and bromoanthraquinone, Tetracyanoquinodimethane compounds, 2,4,7-trinite Polymers having, in the main chain or side chain, a group consisting of fluorenone compounds such as rofluorenone, 2,4,5,7-tetranitro-9-fluorenone, electron transport materials such as xanthone compounds and thiophene compounds, and the above compounds Etc. These charge transport materials may be used alone or in combination of two or more.

The content of the charge transport material is preferably 40% by mass or more, desirably 40% by mass or more and 70% by mass or less, more desirably, based on the mass obtained by subtracting the mass of the silica particles from the mass of all components of the charge transport layer. It is 40 mass% or more and 60 mass% or less.
Further, the content of the charge transport material is preferably smaller than that of the silica particles.
When the content of the charge transport material is within the above range, the generation of the residual potential is easily suppressed.

Examples of the silica particles include dry silica particles and wet silica particles.
Examples of the dry silica particles include combustion method silica (fumed silica) obtained by burning a silane compound and deflagration method silica obtained by explosively burning metal silicon powder.
Wet silica particles include wet silica particles obtained by neutralization reaction between sodium silicate and mineral acid (precipitation silica synthesized and aggregated under alkaline conditions, gel silica particles synthesized and aggregated under acidic conditions), and acidic silicic acid. Examples thereof include colloidal silica particles (silica sol particles) obtained by polymerization with alkalinity, and sol-gel silica particles obtained by hydrolysis of an organic silane compound (for example, alkoxysilane).
Among these, silica particles have low surface silanol groups and a low void structure from the viewpoint of generation of residual potential and suppression of image defects due to deterioration of electrical characteristics (inhibition of deterioration of fine line reproducibility). Silica particles are desirable.

The volume average particle diameter of the silica particles is, for example, preferably from 20 nm to 200 nm, desirably from 30 nm to 200 nm, and more desirably from 40 nm to 150 nm.
When the volume average particle diameter is in the above range, the inorganic protective layer is easily cracked and residual potential is easily suppressed.
The volume average particle size is determined by separating silica particles from the layer, observing 100 primary particles of the silica particles with a scanning electron microscope (SEM) apparatus at a magnification of 40000 times, and analyzing each primary particle by image analysis of the primary particles. The longest diameter and the shortest diameter are measured, and the equivalent sphere diameter is measured from the intermediate value. The 50% diameter (D50v) in the cumulative frequency of the obtained sphere equivalent diameter is obtained, and this is measured as the volume average particle diameter of the silica particles.

The surface of the silica particles is preferably surface-treated with a hydrophobizing agent. Thereby, silanol groups on the surface of the silica particles are reduced, and generation of residual potential is easily suppressed.
Examples of the hydrophobizing agent include known silane compounds such as chlorosilane, alkoxysilane, and silazane.
Among these, as the hydrophobizing agent, a silane compound having a trimethylsilyl group, a decylsilyl group, or a phenylsilyl group is desirable from the viewpoint of easily suppressing the occurrence of a residual potential. That is, the surface of the silica particles preferably has a trimethylsilyl group, a decylsilyl group, or a phenylsilyl group.
Examples of the silane compound having a trimethylsilyl group include trimethylchlorosilane, trimethylmethoxysilane, 1,1,1,3,3,3-hexamethyldisilazane, and the like.
Examples of the silane compound having a decylsilyl group include decyltrichlorosilane, decyltrichlorosilane, decyldimethylchlorosilane, and decyltrimethoxysilane.
Examples of the silane compound having a phenyl group include triphenylmethoxysilane and triphenylchlorosilane.

The condensation rate of the hydrophobized silica particles (Si—O—Si ratio in the SiO ₄ — bond in the silica particles: hereinafter referred to as “condensation rate of the hydrophobizing agent”) is, for example, the surface of the silica particles. It is 90% or more with respect to the silanol group, desirably 91% or more, and more desirably 95% or more.
When the condensation rate of the hydrophobizing agent is within the above range, the silanol groups of the silica particles are reduced, and the occurrence of residual potential is easily suppressed.

The condensation rate of the hydrophobizing agent indicates the ratio of condensed silicon to the total bondable sites of silicon in the condensed portion detected by NMR, and is measured as follows.
First, silica particles are separated from the layer. The separated silica particles were subjected to Si CP / MAS NMR analysis using a Bruker AVANCE III 400 to determine the peak area according to the number of substitutions of SiO, and each of the two substitutions (Si (OH) ₂ (0-Si) ₂ -), 3-substituted (Si (OH) (0- Si) 3 -), 4 -substituted _{(Si (0-Si) 4} -) the value of the Q2, Q3, Q4, the condensation ratio of hydrophobic treatment agent formula : (Q2 × 2 + Q3 × 3 + Q4 × 4) / 4 × (Q2 + Q3 + Q4)

The volume resistivity of the silica particles is, for example, preferably 10 ¹¹ Ω · cm or more, desirably 10 ¹² Ω · cm or more, more desirably 10 ¹³ Ω · cm or more.
When the volume resistivity of the silica particles is in the above range, deterioration of fine line reproducibility is suppressed.

The volume resistivity of the silica particles is measured as follows. The measurement environment is a temperature of 20 ° C. and a humidity of 50% RH.
First, silica particles are separated from the layer. Then, the separated silica particles to be measured are placed on the surface of a circular jig provided with a 20 cm ² electrode plate so as to have a thickness of about 1 mm or more and 3 mm or less to form a silica particle layer. A 20 cm ² electrode plate similar to the above is placed on this and the silica particle layer is sandwiched. In order to eliminate voids between the silica particles, a load of 4 kg is applied on the electrode plate placed on the silica particle layer, and then the thickness (cm) of the silica particle layer is measured. Both electrodes above and below the hydrophobized silica particle layer are connected to an electrometer and a high-voltage power generator. A high voltage is applied to both electrodes so that the electric field becomes a predetermined value, and the current value (A) flowing at this time is read to calculate the volume resistivity (Ω · cm) of the silica particles. The calculation formula of the volume resistivity (Ω · cm) of the silica particles is as shown in the following formula.
In the formula, ρ is the volume resistivity (Ω · cm) of the hydrophobized silica particles, E is the applied voltage (V), I is the current value (A), and I ₀ is the current value (A) at the applied voltage of 0V. , L represents the thickness (cm) of the hydrophobized silica particle layer, respectively. In this evaluation, the volume resistivity when the applied voltage was 1000 V was used.
Formula: ρ = E × 20 / (I−I ₀ ) / L

The content of the silica particles is, for example, preferably 30% by mass or more and 70% by mass or less, desirably 40% by mass or more and 70% by mass or less, and more desirably 45% by mass or more and 65% by mass or less with respect to the entire charge transport layer. It is.
Further, the content of the silica particles is preferably larger than the content of the charge transport material.
When the content of the silica particles is within the above range, cracking of the inorganic protective layer and occurrence of residual potential are easily suppressed.

  Examples of the binder resin constituting the charge transport layer include polycarbonate resins such as bisphenol A type and bisphenol Z type. The mixing ratio between the charge transport material and the binder resin is preferably 10: 1 to 1: 5, for example.

-Characteristics of charge transport layer The surface roughness Ra (arithmetic average surface roughness Ra) of the surface on the inorganic protective layer side in the charge transport layer is, for example, 0.06 μm or less, desirably 0.03 μm or less, more desirably 0.02 μm or less.
When the surface roughness Ra is within the above range, the cleaning property is improved.
In addition, in order to make surface roughness Ra into the said range, methods, such as increasing the thickness of the layer to mix | blend, are mentioned, for example.

The surface roughness Ra is measured as follows.
First, after peeling off the inorganic protective layer, the layer to be measured is exposed. And a part of the layer is cut out with a cutter etc., and a measurement sample is acquired.
The measurement sample is measured using a stylus type surface roughness measuring machine (Surfcom 1400A: manufactured by Tokyo Seimitsu Co., Ltd.). As the measurement conditions, based on JIS B0601-1994, the evaluation length Ln = 4 mm, the reference length L = 0.8 mm, and the cut-off value = 0.8 mm.

The elastic modulus of the charge transport layer is, for example, 5 GPa or more, desirably 6 GPa or more, and more desirably 6.5 GPa or more.
When the elastic modulus of the charge transport layer is in the above range, cracking of the inorganic protective layer is easily suppressed.
In order to set the elastic modulus of the charge transport layer within the above range, for example, a method of adjusting the particle size and content of silica particles and a method of adjusting the type and content of the charge transport material can be mentioned.

The elastic modulus of the charge transport layer is measured as follows.
First, after peeling off the inorganic protective layer, the layer to be measured is exposed. And a part of the layer is cut out with a cutter etc., and a measurement sample is acquired.
For this measurement sample, a depth profile was obtained by the continuous stiffness method (CSM) (US Pat. No. 4,848,141) using Nano Indenter SA2 manufactured by MTS Systems, and the indentation depth was obtained from the measured values of 30 nm to 100 nm. Measure using the average value.

The thickness of the charge transport layer is, for example, 10 μm or more and 40 μm or less, desirably 10 μm or more and 35 μm or less, and more desirably 15 μm or more and 30 μm or less.
When the thickness of the charge transport layer is within the above range, cracking of the inorganic protective layer and generation of residual potential are easily suppressed.

-Formation of charge transport layer The formation of the charge transport layer is not particularly limited, and a well-known formation method is used. For example, a coating film of a charge transport layer forming coating solution in which the above components are added to a solvent is formed. The coating film is dried and heated as necessary.

  Examples of the method for applying the charge transport layer forming coating solution onto the charge generation layer include dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, curtain coating, and the like. The usual method is used.

  When particles (for example, silica particles or fluororesin particles) are dispersed in the charge transport layer forming coating solution, the dispersion method may be media dispersion such as ball mill, vibration ball mill, attritor, sand mill, horizontal sand mill, etc. A medialess disperser such as an agitator, an agitator, an ultrasonic disperser, a roll mill, or a high-pressure homogenizer is used. Examples of the high-pressure homogenizer include a collision method in which a 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.

-Inorganic protective layer-
-Composition of an inorganic protective layer An inorganic protective layer is a layer comprised including the inorganic material.
Examples of the inorganic material include oxide-based, nitride-based, carbon-based, and silicon-based inorganic materials from the viewpoint of having mechanical strength and translucency as a protective layer.
Examples of the oxide-based inorganic material include metal oxides such as gallium oxide, aluminum oxide, zinc oxide, titanium oxide, indium oxide, tin oxide, and boron oxide, or mixed crystals thereof.
Examples of the nitride-based inorganic material include metal nitrides such as gallium nitride, aluminum nitride, zinc nitride, titanium nitride, indium nitride, tin nitride, and boron nitride, or mixed crystals thereof.
Examples of carbon-based and silicon-based inorganic materials include diamond-like carbon (DLC), amorphous carbon (a-C), hydrogenated amorphous carbon (aC: H), hydrogen / fluorinated amorphous carbon (a-C). : H), amorphous silicon carbide (a-SiC), hydrogenated amorphous silicon carbide (a-SiC: H) amorphous silicon (a-Si), hydrogenated amorphous silicon (a-Si: H), and the like. .
Note that the inorganic material may be a mixed crystal of an oxide-based and nitride-based inorganic material.

Among these, as an inorganic material, a metal oxide is excellent in mechanical strength and translucency, in particular from the viewpoint of having n-type conductivity and excellent conductivity controllability. A Group 13 element oxide (preferably gallium oxide) is desirable.
That is, the inorganic protective layer preferably includes at least a group 13 element (particularly gallium) and oxygen, and may include hydrogen as necessary. By including hydrogen, various physical properties of the inorganic protective layer including at least a group 13 element (particularly gallium) and oxygen can be easily controlled. For example, in an inorganic protective layer containing gallium, oxygen, and hydrogen (an inorganic protective layer made of gallium oxide containing hydrogen), the composition ratio [O] / [Ga] is changed from 1.0 to 1.5. Thus, the volume resistivity can be easily controlled in the range of 10 ⁹ Ω · cm to 10 ¹⁴ Ω · cm.

  In addition to the above inorganic material, the inorganic protective layer may contain one or more elements selected from C, Si, Ge, and Sn in the case of n-type, for example, in order to control the conductivity type. For example, in the case of p-type, it may contain one or more elements selected from N, Be, Mg, Ca, and Sr.

Here, when the inorganic protective layer includes gallium, oxygen, and hydrogen as necessary, it is preferable from the viewpoint of excellent mechanical strength, translucency, flexibility, and excellent conductivity controllability. The major element composition ratios are as follows.
The elemental composition ratio of gallium is, for example, preferably 15 atomic percent or more and 50 atomic percent or less, preferably 20 atomic percent or more and 40 atomic percent or less, more desirably 20 atoms, with respect to all the structural elements of the inorganic protective layer. % To 30 atomic%.
The elemental composition ratio of oxygen is, for example, preferably 30 atomic% or more and 70 atomic% or less, preferably 40 atomic% or more and 60 atomic% or less, more preferably 45 atoms, with respect to all the structural elements of the inorganic protective layer. % To 55 atomic%.
The elemental composition ratio of hydrogen is, for example, preferably 10 atomic percent or more and 40 atomic percent or less, preferably 15 atomic percent or more and 35 atomic percent or less, more preferably 20 atoms, with respect to all the constituent elements of the inorganic protective layer. % To 30 atomic%.
On the other hand, the atomic ratio [oxygen / gallium] is preferably more than 1.50 and not more than 2.20, and more preferably not less than 1.6 and not more than 2.0.

Here, the elemental composition ratio, the atomic ratio, etc. of each element in the inorganic protective layer are determined by Rutherford back scattering (hereinafter referred to as “RBS”) including the distribution in the thickness direction. NEC 3SDH Pelletron, CE & A RBS-400 as the end station, and 3S-R10 as the system are used. The analysis uses the CE & A HYPRA program.
The RBS measurement conditions are: He ++ ion beam energy is 2.275 eV, detection angle is 160 °, and Grazing Angle is about 109 ° with respect to the incident beam.

Specifically, the RBS measurement is performed as follows. First, a He ++ ion beam is incident perpendicularly to the sample, the detector is set at 160 ° with respect to the ion beam, and the back scattered He signal is measured. Measure. The composition ratio and the film thickness are determined from the detected energy and intensity of He. In order to improve the accuracy of obtaining the composition ratio and the film thickness, the spectrum may be measured at two detection angles. Accuracy is improved by measuring and cross-checking at two detection angles with different depth resolution and backscattering dynamics.
The number of He atoms back-scattered by the target atom is determined only by three factors: 1) the atomic number of the target atom, 2) the energy of the He atom before scattering, and 3) the scattering angle. From the measured composition, the density is assumed by calculation, and the thickness is calculated using this. The density error is within 20%.

The elemental composition ratio of hydrogen is obtained by hydrogen forward scattering (hereinafter referred to as “HFS”).
In HFS measurement, NEC 3SDH Pelletron is used as an accelerator, CE & A RBS-400 is used as an end station, and 3S-R10 is used as a system. The analysis uses the CE & A HYPRA program. And the measurement conditions of HFS are as follows.
-He ++ ion beam energy: 2.275 eV
Detection angle: Grazing Angle 30 ° with respect to 160 ° incident beam

The HFS measurement picks up the hydrogen signal scattered in front of the sample by setting the detector at 30 ° to the He ++ ion beam and the sample at 75 ° from the normal. At this time, the detector is preferably covered with aluminum foil to remove He atoms scattered together with hydrogen. The quantification is performed by comparing the hydrogen counts of the reference sample and the sample to be measured after normalization with the stopping power. As a reference sample, a sample obtained by ion-implanting H into Si and muscovite are used.
It is known that muscovite has a hydrogen concentration of 6.5 atomic%.
The H adsorbed on the outermost surface is corrected by subtracting the amount of H adsorbed on the clean Si surface, for example.

-Property of inorganic protective layer The inorganic protective layer may have a distribution in the composition ratio in the thickness direction or may have a multilayer structure depending on the purpose.

The inorganic protective layer is preferably a non-single crystal film such as a microcrystalline film, a polycrystalline film, or an amorphous film. Among these, amorphous is particularly desirable in terms of surface smoothness, but a microcrystalline film is more desirable in terms of hardness.
Although the growth cross section of the inorganic protective layer may have a columnar structure, a structure with high flatness is desirable from the viewpoint of slipperiness, and amorphous is desirable.
Crystallinity and amorphousness are determined by the presence or absence of points or lines in a diffraction image obtained by RHEED (reflection high-energy electron diffraction) measurement.

The volume resistivity of the inorganic protective layer is preferably 10 ⁶ Ω · cm or more, and preferably 10 ⁸ Ω · cm or more.
When the volume resistivity is in the above range, the flow of electric charges is suppressed and the formation of a good electrostatic latent image is easily realized.
This volume resistivity is obtained by calculation based on the electrode area and the sample thickness from the resistance value measured under the conditions of a frequency of 1 kHz and a voltage of 1 V using an LF meter ZM2371 manufactured by nF.
The measurement sample is a sample obtained by forming a gold electrode on the aluminum substrate by vacuum deposition on the film under the same conditions as those for forming the inorganic protective layer to be measured. Alternatively, it may be a sample in which the inorganic protective layer is peeled off from the electrophotographic photosensitive member after production, and is partially etched, and is sandwiched between a pair of electrodes.

The elastic modulus of the inorganic protective layer is preferably 30 GPa or more and 80 GPa or less, and preferably 40 GPa or more and 65 GPa or less.
When this elastic modulus is within the above range, the formation of concave portions (scratch-like scratches), peeling and cracking of the inorganic protective layer can be easily suppressed.
This elastic modulus is an average value obtained from a measured value from an indentation depth of 30 nm to 100 nm by obtaining a depth profile by a continuous stiffness method (CSM) (US Pat. No. 4,848,141) using Nano Instor SA2 manufactured by MTS Systems. Is used. The following are the measurement conditions.
・ Measurement environment: 23 ℃, 55% RH
-Indenter used: Diamond regular triangular pyramid indenter (Berkovic indenter) triangular pyramid indenter-Test mode: CSM mode Note that the measurement sample was formed on the substrate under the same conditions as those for forming the inorganic protective layer to be measured. It may be a sample, or a sample obtained by peeling off the inorganic protective layer from the electrophotographic photosensitive member after fabrication and partially etching it.

The film thickness of the inorganic protective layer is, for example, preferably from 0.2 μm to 10.0 μm, and preferably from 0.4 μm to 5.0 μm.
When this film thickness is in the above range, the occurrence of a concave portion (scratch-like scratch), peeling or cracking of the inorganic protective layer is easily suppressed.

-Formation of inorganic protective layer For the formation of the protective layer, for example, a known vapor deposition method such as plasma CVD (Chemical Vapor Deposition), metal organic vapor phase epitaxy, molecular beam epitaxy, vapor deposition, sputtering or the like is used. Is done.

  Hereinafter, the formation of the inorganic protective layer will be described with reference to specific examples while showing an example of the film forming apparatus in the drawings. In addition, although the following description shows the formation method of the inorganic protective layer comprised including gallium, oxygen, and hydrogen, it is not restricted to this, According to the composition of the target inorganic protective layer, a well-known formation method Should be applied.

  FIG. 4 is a schematic diagram showing an example of a film forming apparatus used for forming the inorganic protective layer of the electrophotographic photosensitive member according to the present embodiment, and FIG. 4A is a case where the film forming apparatus is viewed from the side. 4B is a schematic cross-sectional view taken along line A1-A2 of the film formation apparatus illustrated in FIG. 4A. In FIG. 4, 210 is a film forming chamber, 211 is an exhaust port, 212 is a substrate rotating unit, 213 is a substrate support member, 214 is a substrate, 215 is a gas introduction pipe, and 216 is a gas introduced from a gas introduction pipe 215. A shower nozzle having an opening, 217 is a plasma diffusion unit, 218 is a high-frequency power supply unit, 219 is a flat plate electrode, 220 is a gas introduction tube, and 221 is a high-frequency discharge tube unit.

In the film forming apparatus shown in FIG. 4, an exhaust port 211 connected to a vacuum exhaust device (not shown) is provided at one end of the film forming chamber 210, and the side on which the exhaust port 211 of the film forming chamber 210 is provided. On the opposite side, a plasma generator comprising a high-frequency power supply unit 218, a plate electrode 219, and a high-frequency discharge tube unit 221 is provided.
This plasma generator is arranged in a high frequency discharge tube portion 221, a high frequency discharge tube portion 221, a flat plate electrode 219 having a discharge surface provided on the exhaust port 211 side, a high frequency discharge tube portion 221 and a flat plate. The high-frequency power supply unit 218 is connected to the surface of the electrode 219 opposite to the discharge surface. The high-frequency discharge tube portion 221 is connected to a gas introduction tube 220 for supplying gas into the high-frequency discharge tube portion 221, and the other end of the gas introduction tube 220 is a first not shown. Connected to the gas supply.

  Note that the plasma generator shown in FIG. 5 may be used instead of the plasma generator provided in the deposition apparatus shown in FIG. FIG. 5 is a schematic diagram showing another example of the plasma generator used in the film forming apparatus shown in FIG. 4, and is a side view of the plasma generator. In FIG. 5, 222 is a high frequency coil, 223 is a quartz tube, and 220 is the same as that shown in FIG. This plasma generator comprises a quartz tube 223 and a high-frequency coil 222 provided along the outer peripheral surface of the quartz tube 223, and one end of the quartz tube 223 is a film forming chamber 210 (not shown in FIG. 5). It is connected. A gas introduction tube 220 for introducing gas into the quartz tube 223 is connected to the other end of the quartz tube 223.

In FIG. 4, a rod-shaped shower nozzle 216 extending along the discharge surface is connected to the discharge surface side of the flat plate electrode 219, and one end of the shower nozzle 216 is connected to a gas introduction pipe 215. The introduction pipe 215 is connected to a second gas supply source (not shown) provided outside the film formation chamber 210.
In addition, a substrate rotating unit 212 is provided in the film forming chamber 210, and the substrate supporting member is arranged so that the cylindrical substrate 214 faces along the longitudinal direction of the shower nozzle 216 and the axial direction of the substrate 214. It can be attached to the base rotating part 212 via 213. During film formation, the substrate 214 rotates in the circumferential direction by rotating the substrate rotating unit 212. As the substrate 214, for example, a photoconductor previously laminated up to the organic photosensitive layer is used.

The inorganic protective layer is formed as follows, for example.
First, oxygen gas (or helium (He) diluted oxygen gas), helium (He) gas, and hydrogen (H ₂ ) gas as needed are introduced into the high-frequency discharge tube portion 221 from the gas introduction tube 220, and A radio wave of 13.56 MHz is supplied from the high frequency power supply unit 218 to the plate electrode 219. At this time, the plasma diffusion portion 217 is formed so as to spread radially from the discharge surface side of the plate electrode 219 to the exhaust port 211 side. Here, the gas introduced from the gas introduction pipe 220 flows through the film forming chamber 210 from the plate electrode 219 side to the exhaust port 211 side. The plate electrode 219 may be one in which the electrode is surrounded by a ground shield.

Next, trimethylgallium gas is introduced into the film formation chamber 210 through a gas introduction pipe 215 and a shower nozzle 216 located downstream of the plate electrode 219 serving as an activating means. A non-single-crystal film containing hydrogen is formed.
As the substrate 214, for example, a substrate on which an organic photosensitive layer is formed is used.

The temperature of the surface of the substrate 214 during the formation of the inorganic protective layer is preferably 150 ° C. or lower, more preferably 100 ° C. or lower, and particularly preferably 30 ° C. or higher and 100 ° C. or lower because an organic photoreceptor having an organic photosensitive layer is used.
Even if the temperature of the surface of the substrate 214 is 150 ° C. or less at the beginning of film formation, if the temperature is higher than 150 ° C. due to the influence of plasma, the organic photosensitive layer may be damaged by heat. Thus, it is desirable to control the surface temperature of the substrate 214.
The temperature of the surface of the substrate 214 may be controlled by heating and / or cooling means (not shown in the figure), or may be left to a natural temperature increase during discharge. In the case of heating the base 214, a heater may be installed outside or inside the base 214. When the substrate 214 is cooled, a cooling gas or liquid may be circulated inside the substrate 214.
In order to avoid an increase in the temperature of the surface of the substrate 214 due to electric discharge, it is effective to adjust a high-energy gas flow that strikes the surface of the substrate 214. In this case, conditions such as the gas flow rate, discharge output, and pressure are adjusted so as to achieve the required temperature.

Further, instead of trimethylgallium gas, hydrides such as organometallic compounds containing aluminum and diborane may be used, and two or more of these may be mixed.
For example, in the initial stage of forming the inorganic protective layer, trimethylindium is introduced into the deposition chamber 210 through the gas introduction tube 215 and the shower nozzle 216, thereby forming a film containing nitrogen and indium on the substrate 214. In this case, the film absorbs ultraviolet rays that are generated when the film is continuously formed and deteriorate the organic photosensitive layer. For this reason, damage to the organic photosensitive layer due to generation of ultraviolet rays during film formation is suppressed.

Further, as a dopant doping method during film formation, SiH ₃ and SnH ₄ are used for n-type, and biscyclopentadienylmagnesium, dimethyl calcium, dimethylstrontium, etc. are used in a gas state for p-type. use. In order to dope the dopant element into the surface layer, a known method such as a thermal diffusion method or an ion implantation method may be employed.
Specifically, for example, by introducing a gas containing at least one dopant element into the film formation chamber 210 via the gas introduction pipe 215 and the shower nozzle 216, a conductive type such as n-type or p-type is used. An inorganic protective layer is obtained.

In the film formation apparatus described with reference to FIGS. 4 and 5, active nitrogen or active hydrogen formed by discharge energy may be controlled independently by providing a plurality of active apparatuses, or with nitrogen atoms such as NH _3. You may use the gas which contains a hydrogen atom simultaneously. Further, H ₂ may be added. Alternatively, conditions under which active hydrogen is liberated from an organometallic compound may be used.
By doing so, activated carbon atoms, gallium atoms, nitrogen atoms, hydrogen atoms, and the like exist on the surface of the substrate 214 in a controlled state. Then, the activated hydrogen atom has an effect of desorbing hydrogen of a hydrocarbon group such as a methyl group or an ethyl group constituting the organometallic compound as a molecule.
For this reason, a hard film (inorganic protective layer) constituting a three-dimensional bond is formed.

The plasma generating means of the film forming apparatus shown in FIGS. 4 and 5 uses a high-frequency oscillator, but is not limited to this. For example, a microwave oscillator or an electrocyclotron resonance method is used. Alternatively, a helicon plasma type apparatus may be used. Further, in the case of a high-frequency oscillation device, it may be inductive or capacitive.
Furthermore, two or more of these devices may be used in combination, or two or more of the same types of devices may be used. In order to suppress the temperature rise on the surface of the substrate 214 by plasma irradiation, a high-frequency oscillation device is desirable, but a device for suppressing heat irradiation may be provided.

  When two or more different plasma generators (plasma generating means) are used, it is desirable that discharges are generated simultaneously at the same pressure. In addition, a pressure difference may be provided between the discharge area and the film formation area (the portion where the base is installed). These apparatuses may be arranged in series with respect to the gas flow formed in the film forming apparatus from the part where the gas is introduced to the part where the gas is discharged. You may arrange | position so that it may oppose.

For example, when two types of plasma generating means are installed in series with respect to the gas flow, the film forming apparatus shown in FIG. 4 is taken as an example, and a discharge is caused in the film forming chamber 210 using the shower nozzle 216 as an electrode. 2 is used as a plasma generator. In this case, for example, a high frequency voltage is applied to the shower nozzle 216 via the gas introduction pipe 215 to cause discharge in the film forming chamber 210 using the shower nozzle 216 as an electrode. Alternatively, instead of using the shower nozzle 216 as an electrode, a cylindrical electrode is provided between the substrate 214 and the plate electrode 219 in the film forming chamber 210, and this film is used to form the film forming chamber 210. Causes a discharge inside.
In addition, when two different types of plasma generators are used under the same pressure, for example, when using a microwave oscillator and a high-frequency oscillator, the excitation energy of the excited species can be greatly changed, and the film quality can be controlled. It is valid. Moreover, you may perform discharge by atmospheric pressure vicinity (70000 Pa or more and 110000 Pa or less). When discharging near atmospheric pressure, it is desirable to use He as a carrier gas.

  For forming the inorganic protective layer, for example, the base 214 having an organic photosensitive layer formed on the base is placed in the film forming chamber 210, and mixed gases having different compositions are introduced to form the inorganic protective layer.

As film formation conditions, for example, when discharging is performed by high-frequency discharge, it is desirable that the frequency be in the range of 10 kHz to 50 MHz in order to perform high-quality film formation at a low temperature. Further, the output is dependent on the size of the substrate 214, it is desirable to 0.01 W / cm ² or more 0.2 W / cm ² or less in the range of the surface area of the substrate. The rotation speed of the substrate 214 is desirably in the range of 0.1 rpm to 500 rpm.

As described above, an example in which the organic photosensitive layer is a function separation type and the charge transport layer is a single layer type as an electrophotographic photoreceptor has been described. However, the electrophotographic photoreceptor shown in FIG. In the case where the transport layer is a multilayer type), the charge generation layer 3A in contact with the inorganic protective layer 5 has the same configuration as the charge transport layer 3 of the electrophotographic photosensitive member shown in FIG. The charge transport layer 3B not to be used may have the same configuration as a known charge transport layer.
However, the film thickness of the charge generation layer 3A is preferably 1 μm or more and 15 μm or less. The film thickness of the charge transport layer 3B is preferably 15 μm or more and 29 μm.

On the other hand, in the case of the electrophotographic photoreceptor shown in FIG. 3 (example where the organic photosensitive layer is a single layer type), the single-layer-side organic photosensitive layer 6 (charge generation / charge transport layer) is the charge transport layer of the electrophotographic photoreceptor. 3 and the charge generating material are preferably used except that the charge generating material is included.
However, the content of the charge generating material in the single-layer side organic photosensitive layer 6 is preferably 25% by mass or more and 50% by mass or less with respect to the entire single-layer side organic photosensitive layer.
The film thickness of the single-layer side organic photosensitive layer 6 is preferably 15 μm or more and 30 μm.

(Process cartridge and image forming apparatus)
FIG. 6 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present embodiment.
As shown in FIG. 6, 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 (the electrophotographic photosensitive member according to the present embodiment). And a charging device 20 (an example of a charging unit) that is provided above the electrophotographic photosensitive member 10 and is opposed to the electrophotographic photosensitive member 10 and charges the surface of the electrophotographic photosensitive member 10. An exposure device 30 (an example of an electrostatic latent image forming unit) that exposes the surface of the electrophotographic photoreceptor 10 to form an electrostatic latent image, and the electrostatic latent image formed by the exposure device 30 is included in the developer. A developing device 40 (an example of a developing unit) that forms a toner image on the surface of the electrophotographic photosensitive member 10 by adhering the toner to be moved, while traveling in the direction indicated by the arrow b while being in contact with the electrophotographic photosensitive member 10, On the surface of the photoconductor 10 Comprises an intermediate transfer member 50 belt-shaped for transferring the made toner image, and a cleaning device 70 for cleaning the surface of the electrophotographic photosensitive member 10 (an example of a cleaning unit).

  The charging device 20, the exposure device 30, the developing device 40, the intermediate transfer member 50, the lubricant supply device 60, and the cleaning device 70 are arranged in a clockwise direction on the circumference surrounding the electrophotographic photosensitive member 10. In this embodiment, a mode in which the lubricant supply device 60 is disposed inside the cleaning device 70 will be described. However, the present invention is not limited to this, and the lubricant supply device 60 is disposed separately from the cleaning device 70. It may be in the form.

  The intermediate transfer member 50 is held from the inside while being tensioned by the support rollers 50A and 50B, the back roller 50C, and the drive roller 50D, and is driven in the direction of the arrow b as the drive roller 50D rotates. At a position facing the electrophotographic photosensitive member 10 inside the intermediate transfer member 50, the intermediate transfer member 50 is charged to a polarity different from the charging polarity of the toner, and the electrophotographic photosensitive member 10 is placed on the outer surface of the intermediate transfer member 50. A primary transfer device 51 for adsorbing the upper toner is provided. On the outer side below the intermediate transfer member 50, the recording paper P (an example of a recording medium) is charged to a polarity different from the charged polarity of the toner, and the toner image formed on the intermediate transfer member 50 is placed on the recording paper P. A secondary transfer device 52 for transferring is provided to face the back roller 50C. These members for transferring the toner image formed on the electrophotographic photosensitive member 10 to the recording paper P correspond to an example of a transfer unit.

  Below the intermediate transfer member 50, a recording paper supply device 53 that supplies the recording paper P to the secondary transfer device 52 and a recording paper P on which the toner image is formed in the secondary transfer device 52 are conveyed. A fixing device 80 for fixing the toner image is provided.

  The recording paper supply device 53 includes a pair of transport rollers 53A and a guide slope 53B that guides the recording paper P transported by the transport rollers 53A toward the secondary transfer device 52. On the other hand, the fixing device 80 includes a fixing roller 81 that is a pair of heat rollers for fixing the toner image by heating and pressing the recording paper P onto which the toner image has been transferred by the secondary transfer device 52, and a fixing roller. And a conveyance conveyor 82 that conveys the recording paper P toward 81.

  The recording paper P is conveyed in the direction indicated by the arrow c by the recording paper supply device 53, the secondary transfer device 52, and the fixing device 80.

  The intermediate transfer member 50 is further provided with an intermediate transfer member cleaning device 54 having a cleaning blade for removing the toner remaining on the intermediate transfer member 50 after the toner image is transferred to the recording paper P in the secondary transfer device 52. Yes.

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

-Charging device-
Examples of the charging device 20 include a contact charger using a conductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube, and the like. Further, examples of the charging device 20 include a non-contact type roller charger and a known charger such as a scorotron charger using a corona discharge or a corotron charger. As the charging device 20, a contact charger is preferable.

-Exposure device-
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. The wavelength of the semiconductor laser is preferably near infrared having an oscillation wavelength of around 780 nm, for example. However, the present invention is not limited to this wavelength, and an oscillation wavelength laser in the 600 nm range or a laser having an oscillation wavelength of 400 nm to 450 nm as a blue laser may be used. 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-
The developing device 40 is disposed, for example, opposite to the electrophotographic photoreceptor 10 in the developing region, and includes, for example, a developing container 41 (developing device main body) that contains a two-component developer composed of toner and a carrier, and a replenishment device. A developer storage container (toner cartridge) 47. The developing container 41 includes a developing container main body 41A and a developing container cover 41B that closes the upper end thereof.

  The developing container main body 41A has, for example, a developing roll chamber 42A that accommodates the developing roll 42 therein, and is adjacent to the first stirring chamber 43A and the first stirring chamber 43A adjacent to the developing roll chamber 42A. Second agitating chamber 44A. Further, in the developing roll chamber 42A, for example, a layer thickness regulating member 45 for regulating the layer thickness of the developer on the surface of the developing roll 42 is provided when the developing container cover 41B is attached to the developing container main body 41A. Yes.

  The first stirring chamber 43A and the second stirring chamber 44A are partitioned by, for example, a partition wall 41C. Although not shown, the first stirring chamber 43A and the second stirring chamber 44A are arranged in the longitudinal direction of the partition wall 41C (developing device). (Longitudinal direction) Openings are provided at both ends, and the circulation stirring chamber (43A + 44A) is constituted by the first stirring chamber 43A and the second stirring chamber 44A.

  The developing roll 42 is disposed in the developing roll chamber 42 </ b> A so as to face the electrophotographic photoreceptor 10. Although not shown, the developing roll 42 is provided with a sleeve outside a magnetic roll (fixed magnet) having magnetism. The developer in the first stirring chamber 43A is adsorbed on the surface of the developing roll 42 by the magnetic force of the magnetic roll and is transported to the developing area. Further, the developing roller 42 has a roll shaft supported rotatably on the developing container main body 41A. Here, the developing roll 42 and the electrophotographic photoreceptor 10 rotate in the same direction, and the developer adsorbed on the surface of the developing roll 42 at the opposite portion is opposite to the traveling direction of the electrophotographic photoreceptor 10. It is conveyed from the direction to the development area.

  Further, a bias power source (not shown) is connected to the sleeve of the developing roll 42 so that a developing bias is applied (in this embodiment, a direct current component is applied so that an alternating electric field is applied to the developing region. (A bias in which an alternating current component (DC) is superimposed on (AC) is applied).

  In the first stirring chamber 43A and the second stirring chamber 44A, a first stirring member 43 (stirring / conveying member) and a second stirring member 44 (stirring / conveying member) that convey the developer while stirring are disposed. The first stirring member 43 includes a first rotating shaft that extends in the axial direction of the developing roll 42, and an agitating / conveying blade (protrusion) that is helically fixed to the outer periphery of the rotating shaft. Similarly, the second agitating member 44 includes a second rotating shaft and an agitating / conveying blade (protrusion). The stirring member is rotatably supported by the developing container main body 41A. The first stirring member 43 and the second stirring member 44 are arranged such that the developer in the first stirring chamber 43A and the second stirring chamber 44A is conveyed in the opposite directions by rotation thereof. .

  One end of a replenishment conveyance path 46 for supplying replenishment developer including replenishment toner and replenishment carrier to the second agitation chamber 44A is connected to one end side in the longitudinal direction of the second agitation chamber 44A. The other end of the replenishment conveyance path 46 is connected to a replenishment developer storage container 47 that contains a replenishment developer.

  In this manner, the developing device 40 supplies the replenishment developer from the replenishment developer storage container (toner cartridge) 47 to the development device 40 (second stirring chamber 44A) through the replenishment conveyance path 46.

  As the developer used in the developing device 40, for example, a well-known developer such as a one-component developer containing toner alone or a two-component developer containing toner and carrier is employed.

-Transfer device-
Examples of the primary transfer device 51 and the secondary transfer device 52 include a contact transfer charger using a belt, a roller, a film, a rubber blade, and the like, a scorotron transfer charger using a corona discharge, a corotron transfer charger, and the like. A transfer charger known per se can be used.

  As the intermediate transfer member 50, a belt-like member (intermediate transfer belt) such as polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber containing a conductive agent is used. Further, as the form of the intermediate transfer member, a cylindrical one is used in addition to the belt shape.

-Cleaning device-
The cleaning device 70 includes a housing 71, a cleaning blade 72 disposed so as to protrude from the housing 71, and a lubricant supply device 60 disposed downstream of the cleaning blade 72 in the rotation direction of the electrophotographic photosensitive member 10. , Including.
The cleaning blade 72 may be supported by the end portion of the casing 71 or may be separately supported by a support member (holder). The form supported at the end of 71 is shown.

First, the cleaning blade 72 will be described.
Examples of the material constituting the cleaning blade 72 (the cleaning layer 72A and the back layer 72B) include urethane rubber, silicon rubber, fluorine rubber, propylene rubber, and butadiene rubber. Among these, urethane rubber is preferable.
The urethane rubber (polyurethane) is not particularly limited as long as it is usually used for forming polyurethane, for example, a urethane prepolymer comprising a polyol such as a polyester polyol such as polyethylene adipate or polycaprolactone and an isocyanate such as diphenylmethane diisocyanate. For example, it is preferable to use a crosslinking agent such as 1,4-butanediol, trimethylolpropane, ethylene glycol or a mixture thereof as a raw material.

Next, the lubricant supply device 60 will be described.
The lubricant supply device 60 is provided, for example, inside the cleaning device 70 and upstream of the cleaning blade 72 in the rotation direction of the electrophotographic photosensitive member 10.

  The lubricant supply device 60 includes, for example, a rotating brush 61 disposed in contact with the electrophotographic photosensitive member 10 and a solid lubricant 62 disposed in contact with the rotating brush 61. . In the lubricant supply device 60, the rotating brush 61 is rotated while being in contact with the solid lubricant 62, whereby the lubricant 62 adheres to the rotating brush 61, and the attached lubricant 62 becomes the electrophotographic photosensitive member. The film of the lubricant 62 is formed on the surface 10.

  The lubricant supply device 60 is not limited to the above form, and may be a form that employs a rubber roller instead of the rotating brush 61, for example.

-Operation of image forming apparatus-
Next, 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 indicated 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 photoreceptor 10 approaches the developing device 40, the developing device 40 (developing roll 42) attaches toner to the latent image and forms a toner image.

  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 to the outer surface of the intermediate transfer member 50.

  When the toner image is transferred to the intermediate transfer member 50, the recording paper P is supplied to the secondary transfer device 52 by the recording paper supply device 53, and the toner image transferred to the intermediate transfer member 50 is transferred by the secondary transfer device 52. Transferred onto the recording paper P. 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 80.

  Here, after the toner image is transferred to the intermediate transfer member 50, the electrophotographic photosensitive member 10 is transferred, and then the lubricant supply device 60 supplies the lubricant 62 to the surface of the electrophotographic photosensitive member 10. A film of the lubricant 62 is formed on the surface of the photographic photoreceptor 10. Thereafter, the toner and discharge products remaining on the surface are removed by the cleaning blade 72 of the cleaning device 70. Then, the electrophotographic photosensitive member 10 from which the transfer residual toner and discharge products are removed in the cleaning device 70 is charged again by the charging device 20 and is exposed in the exposure device 30 to form a latent image.

Further, for example, as illustrated in FIG. 7, the image forming apparatus 101 according to the present embodiment includes an electrophotographic photosensitive member 10, a charging device 20, a developing device 40, a lubricant supply device 60, and a cleaning in a housing 11. A configuration including a process cartridge 101A that integrally accommodates the apparatus 70 may be employed. The process cartridge 101A integrally contains a plurality of members and is attached to and detached from the image forming apparatus 101. In the image forming apparatus 101 shown in FIG. 7, a form in which the replenishment developer storage container 47 is not provided in the developing device 40 is shown.
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 photoreceptor 10, and for example, the charging device 20, the exposure device 30, the developing device 40, the primary transfer device 51, the lubrication At least one selected from the agent supply device 60 and 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-described configuration. For example, the cleaning is performed around the electrophotographic photosensitive member 10 and downstream of the primary transfer device 51 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 relative to the device 70 so that the polarity of the remaining toner is aligned and easily removed with a cleaning brush. Even if the second static eliminating device for neutralizing the surface of the electrophotographic photosensitive member 10 is provided on the downstream side in the rotational direction of the electrophotographic photosensitive member relative to the upstream side in the rotational direction of the electrophotographic photosensitive member relative to the charging device 20. Good.

  Further, the image forming apparatus 101 according to the present embodiment is not limited to the above-described configuration, and may employ a known configuration, for example, a method of directly transferring a toner image formed on the electrophotographic photosensitive member 10 to the recording paper P. Alternatively, a tandem image forming apparatus may be employed.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the following examples, “part” means part by mass.

[Preparation and production of silica particles]
-Silica particles (0)-
Untreated (hydrophilic) silica particles “trade name: OX50 (manufactured by Aerosil Co., Ltd.)” were prepared and used as silica particles (0).

-Silica particles (11)-
To 100 parts by mass of untreated (hydrophilic) silica particles “trade name: OX50 (manufactured by Aerosil Co., Ltd.)”, trimethoxysilane (“trade name: 1,1,1,3,3,3- 30 parts by mass of hexamethyldisilazane (manufacturer, manufactured by Tokyo Chemical Industry Co., Ltd.)) was added and reacted for 24 hours, and then filtered to obtain hydrophobized silica particles. This was designated as silica particles (11).

-Silica particles (12)-
Hydrophobized silica particles “trade name: RX200 (manufactured by Aerosil Co., Ltd.)” were prepared and used as silica particles (12).

-Silica particles (13)-
Hydrophobized silica particles “trade name: X24-9163A (manufacturer: Shin-Etsu Chemical Co., Ltd.)” were prepared and used as silica particles (13).

-Silica particles (14)-
100 parts by mass of untreated (hydrophilic) silica particles “trade name: OX50 (manufactured by Aerosil Co., Ltd.)”, 200 parts by mass of tetrahydrofuran and trimethylsilane (1,1,1,3,3,3- 30 parts by mass of hexamethyldisilazane (manufactured by Tokyo Chemical Industry Co., Ltd.)) was added and reacted for 12 hours, and then filtered to obtain hydrophobized silica particles. This was designated as silica particles (14).

-Silica particles (15)-
100 parts by mass of untreated (hydrophilic) silica particles “trade name: SFP-20M (manufactured by Denki Kagaku Kogyo Co., Ltd.)”, 200 parts by mass of tetrahydrofuran, trimethylsilane (1,1,1,3,3) as a hydrophobizing agent 30 parts by mass of 3,3-hexamethyldisilazane (manufacturer, manufactured by Tokyo Chemical Industry Co., Ltd.)) was added, reacted for 12 hours, and then filtered to obtain hydrophobized silica particles. This was designated as silica particles (15).

-Silica particles (21)-
100 parts by mass of untreated (hydrophilic) silica particles “trade name: OX50 (manufactured by Aerosil Co., Ltd.)”, 200 parts by mass of tetrahydrofuran, decylsilane (decyltrimethoxysilane) “trade name: KBM-3103 (manufacturer) “Shin-Etsu Chemical Co., Ltd.)”) 30 parts by mass were added and reacted for 24 hours, and then filtered to obtain hydrophobized silica particles. This was designated as silica particles (21).

-Silica particles (31)-
100 parts by mass of untreated (hydrophilic) silica particles “trade name: OX50 (manufactured by Aerosil Co., Ltd.)”, 200 parts by mass of tetrahydrofuran and phenylsilane (phenyltriethoxysilane “trade name: KBE-103” as a hydrophobizing agent) Manufactured by Shin-Etsu Chemical Co., Ltd.))) 30 parts by mass was added and reacted for 24 hours to obtain hydrophobized silica particles. This was designated as silica particles (31).

[Example A]
(Example A1)
-Production of undercoat layer-
Zinc oxide: (average particle diameter 70 nm: manufactured by Teica Co., Ltd .: specific surface area value 15 m ² / g) 100 parts by mass was stirred and mixed with 500 parts by mass of tetrahydrofuran, and silane coupling agent (KBM503: manufactured by Shin-Etsu Chemical Co., Ltd.) 1.3 parts by mass Part was added and stirred for 2 hours. Tetrahydrofuran was then distilled off under reduced pressure and baked at 120 ° C. for 3 hours to obtain a silane coupling agent surface-treated zinc oxide.
110 parts by mass of the surface-treated zinc oxide was stirred and mixed with 500 parts by mass of tetrahydrofuran, a solution prepared by dissolving 0.6 parts by mass of alizarin in 50 parts by mass of tetrahydrofuran was added, and the mixture was stirred at 50 ° C. for 5 hours. did. Then, the zinc oxide to which alizarin was imparted by filtration under reduced pressure was filtered off, and further dried at 60 ° C. under reduced pressure to obtain alizarin imparted zinc oxide.
60 parts by mass of this alizarin-provided zinc oxide and a curing agent (blocked isocyanate Sumijoule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.): 13.5 parts by mass and 15 parts by mass of butyral resin (ESREC BM-1, manufactured by Sekisui Chemical Co., Ltd.) 38 parts by mass of the solution dissolved in 85 parts by mass and 25 parts by mass of methyl ethyl ketone were mixed, and dispersion was performed for 2 hours with a sand mill using 1 mmφ glass beads.
Dioctyltin dilaurate: 0.005 parts by mass and silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone): 40 parts by mass were added as catalysts to the resulting dispersion to obtain an undercoat layer coating solution. This coating solution was 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 to obtain an undercoat layer having a thickness of 19 μm.

-Fabrication of charge generation layer-
Bragg angles (2θ ± 0.2 °) of X-ray diffraction spectrum using Cukα characteristic X-ray as a charge generating material are at least 7.3 °, 16.0 °, 24.9 °, 28.0 ° A mixture consisting of 15 parts by mass of hydroxygallium phthalocyanine having a diffraction peak, 10 parts by mass of vinyl chloride / vinyl acetate copolymer resin (VMCH, manufactured by Nihon Unicar) as a binder resin, and 200 parts by mass of n-butyl acetate, The glass beads having a diameter of 1 mmφ were dispersed for 4 hours by a sand mill. To the obtained dispersion, 175 parts by mass of n-butyl acetate and 180 parts by mass of methyl ethyl ketone were added and stirred to obtain a coating solution for a charge generation layer. This charge generation layer coating solution was dip coated on the undercoat layer and dried at room temperature (25 ° C.) to form a charge generation layer having a thickness of 0.2 μm.

-Preparation of charge transport layer-
95 parts by mass of tetrahydrofuran is added to 20 parts by mass of silica particles (11), and (N, N′-diphenyl-N, N′-bis (3-methylphenyl)-(1,1 ′) is maintained at a liquid temperature of 20 ° C. -Diphenyl) -4,4'-diamine 10 parts by mass, bisphenol Z-type polycarbonate resin (viscosity average molecular weight: 50,000) as a binder resin, 10 parts by mass, and stirred and mixed for 12 hours to form a coating solution for forming a charge transport layer Got.

  This coating solution for forming a charge transport layer was applied onto the charge generation layer and dried at 135 ° C. for 40 minutes to form a charge transport layer having a thickness of 30 μm, thereby obtaining the intended electrophotographic photosensitive member.

  Through the above steps, an organic photoreceptor (hereinafter referred to as “non-coated photoreceptor (1)”) in which an undercoat layer, a charge generation layer, and a charge transport layer are laminated in this order on an aluminum base material was obtained. .

-Formation of inorganic protective layer-
Next, an inorganic protective layer made of gallium oxide containing hydrogen was formed on the surface of the non-coated photoreceptor (1). The inorganic protective layer was formed using a film forming apparatus having the configuration shown in FIG.

First, the non-coated photoreceptor (1) is placed on the substrate support member 213 in the film forming chamber 210 of the film forming apparatus, and the inside of the film forming chamber 210 is evacuated through the exhaust port 211 until the pressure becomes 0.1 Pa. did. The evacuation was performed within 5 minutes after the replacement of the high-concentration oxygen-containing gas.
Next, He diluted 40% oxygen gas (flow rate 1.6 sccm) and hydrogen gas (flow rate 50 sccm) were introduced from the gas introduction tube 220 into the high-frequency discharge tube portion 221 provided with the plate electrode 219 having a diameter of 85 mm, A high frequency power supply unit 218 and a matching circuit (not shown in FIG. 4) set a 13.56 MHz radio wave to an output of 150 W, matched with a tuner, and discharged from the plate electrode 219. The reflected wave at this time was 0 W.
Next, trimethylgallium gas (flow rate: 1.9 sccm) was introduced from the shower nozzle 216 to the plasma diffusion portion 217 in the film formation chamber 210 via the gas introduction tube 215. At this time, the reaction pressure in the film forming chamber 210 measured with a Baratron vacuum gauge was 5.3 Pa.
In this state, the non-coated photoreceptor (1) was formed for 68 minutes while rotating at a speed of 500 rpm, and an inorganic protective layer having a film thickness of 0.25 μm was formed on the surface of the charge transport layer of the non-coated photoreceptor (1).

  Through the above steps, an electrophotographic photoreceptor was obtained in which an undercoat layer, a charge generation layer, a charge transport layer, and an inorganic protective layer were sequentially formed on a conductive substrate.

(Examples A2 to A8, Comparative Example A1)
An electrophotographic photosensitive member was obtained in the same manner as in Example A1 except that the composition and film thickness of the charge transport layer were changed according to Table 2.

(Evaluation A)
-Characteristic evaluation A-
The electrophotographic photoreceptor obtained in each example was examined for the elastic modulus of the charge transport layer according to the method described above.

In addition, the applicability of the electrophotographic photoreceptor obtained in each example was visually evaluated as follows. A: The film was not peeled off and could be applied without precipitation of silica particles.
B: No film peeling, but deposition of silica particles (surface turbidity) was confirmed C: Film peeling occurred

-Actual machine evaluation A-
The electrophotographic photosensitive member obtained in each example is attached to a 700 Digital Color Press manufactured by Fuji Xerox Co., Ltd., and a halftone image (30% image density) is continuously output under a high temperature and high humidity environment (20 ° C., 40% RH). A print test was performed to evaluate the dents of the inorganic protective layer and the electrical characteristics of the photoreceptor.

・ Indentation evaluation of inorganic protective layer After outputting 100 halftone images (image density 30%) continuously, the surface of the electrophotographic photosensitive surface (the surface of the inorganic protective layer) was measured with a laser microscope at 10 magnifications at a magnification of 450 times. The number of dents in the shape of dents was counted, and the number of dents per unit area (1 mm × 1 mm) was calculated.
The evaluation criteria are as follows.
A: Number of dents is 20 or less B: Number of dents exceeds 20 and 100 or less C: Number of dents exceeds 100

-Electrical characteristics The electrical characteristics of the electrophotographic photosensitive member were evaluated by scanner measurement. Specifically, it is as follows.

1. Residual potential (RP)
First, the electrophotographic photosensitive member is rotated at 167 rpm with exposure light (light source: semiconductor laser, wavelength: 780 nm, output: 5 mW) charged at −700 V by a scorotron charger. Irradiation was performed while scanning the surface of the photoreceptor. Thereafter, the potential of the electrophotographic photosensitive member was measured with a surface potentiometer (model 344, manufactured by Trek Japan), and the potential state (residual potential) in the electrophotographic photosensitive member was examined. This was repeated 100 cycles, and the 100th residual potential was measured.
The evaluation criteria are as follows.
A: Residual potential (RP) is 100 V or less B: Residual potential (RP) exceeds 100 V and 150 V or less C: Residual potential (RP) exceeds 150 V

[Example B]
(Examples B1-B5, Comparative Examples B1-B2)
An electrophotographic photosensitive member was obtained in the same manner as in Example A1 except that the composition and film thickness of the charge transport layer were changed according to Table 3.
However, in each example, the film formation time was changed, and the film thickness of the inorganic protective layer was 1 μm.

(Evaluation B)
The electrophotographic photosensitive member obtained in each example was evaluated in the same manner as in Example A with respect to the dent of the inorganic protective layer and the electrical characteristics of the photosensitive member.
In addition, regarding the evaluation of applicability with respect to Comparative Example B2, the cloudiness due to the precipitation of the charge transporting material was examined instead of the precipitation of the silica particles.

[Example C]
(Examples C1 to C3, Comparative Example C1)
According to Table 4, except that the composition and film thickness of the charge transport layer were changed, 20 electrophotographic photosensitive members were produced in the same manner as in Example A1, and the surface roughness Ra of the charge transport layer was high among them. Three of the second highest and average ones were selected and evaluated as electrophotographic photoreceptors of Examples C1 to C3.
Similarly, an electrophotographic photosensitive member was produced in the same manner as in Example A1 except that the composition / film thickness of the charge transport layer was changed according to Table 4, and evaluated as an electrophotographic photosensitive member of Comparative Example C1.

(Evaluation C)
The electrophotographic photoreceptor obtained in each example was evaluated in the same manner as in Example A with respect to coatability, dents on the inorganic protective layer, and electrical characteristics of the photoreceptor. In addition, the cleaning property was also evaluated.

Evaluation of cleaning property The electrophotographic photosensitive member obtained in each example was attached to 700 Digital Color Press manufactured by Fuji Xerox Co., Ltd., and a halftone image (30% image density) under a high temperature and high humidity environment (28 ° C., 80% RH). ) Was output continuously, and then left overnight under a high temperature and high humidity environment (28 ° C., 80% RH). Thereafter, 100 continuous halftone images (image density 30%) were output, and the 100th image was visually evaluated.
The evaluation criteria are as follows.
A: A similar image is output compared to the output image before being left B: Image density of 50% or less of the image area is lower than the output image before being left C: Output before being left The image density of the entire image area is lower than the image

[Example D]
(Examples D1 to D4)
An electrophotographic photosensitive member was obtained in the same manner as in Example A1 except that the composition and film thickness of the charge transport layer were changed according to Table 5.

(Evaluation D)
The electrophotographic photoreceptor obtained in each example was evaluated in the same manner as in Example A with respect to coatability, dents on the inorganic protective layer, and electrical characteristics of the photoreceptor. In addition, fine line reproducibility (resolution) was evaluated.

・ Resolution evaluation The electrophotographic photosensitive member obtained in each example was attached to 700 Digital Color Press manufactured by Fuji Xerox Co., Ltd., and a 5 line pair / mm image was output under a high temperature and high humidity environment (20 ° C., 40% RH). The images were evaluated by observation using an optical microscope 50 ×.
The evaluation criteria are as follows.
A: A similar image (line pair) is output compared to the output image before being left B: The image (line pair) is less linear than the output image before being left, and partly connected C: The image (line pair) is not clear compared to the output image before leaving

[Example E]
(Examples E1 to E4)
According to Table 6, an electrophotographic photosensitive member was obtained in the same manner as in Example A1 except that the composition and film thickness of the charge transport layer were changed.

(Evaluation E)
The electrophotographic photoreceptor obtained in each example was evaluated in the same manner as in Example A with respect to coatability, dents on the inorganic protective layer, and electrical characteristics of the photoreceptor.

[Example F]
(Examples F1 to F2)
According to Table 6, an electrophotographic photosensitive member was obtained in the same manner as in Example A1 except that the composition and film thickness of the charge transport layer were changed.

(Evaluation F)
The electrophotographic photoreceptor obtained in each example was evaluated in the same manner as in Example A with respect to coatability, dents on the inorganic protective layer, and electrical characteristics of the photoreceptor.

[Example G]
(Examples G1 to G4)
An electrophotographic photosensitive member was obtained in the same manner as in Example A1 except that the composition and film thickness of the charge transport layer were changed according to Table 7.

(Evaluation G)
The electrophotographic photoreceptor obtained in each example was evaluated in the same manner as in Example A with respect to coatability, dents on the inorganic protective layer, and electrical characteristics of the photoreceptor. In addition, the fine line reproducibility (resolution) was evaluated in the same manner as in Example D.

Tables 2 to 7 below show a list of evaluation results together with details of each example.
However, abbreviations in the table are as follows.
D50: Volume average particle diameter TMS: Trimethylsilane DS: Decylsilane FS: Phenylsilane Condensation rate of silica particles; Condensation rate of hydrophobizing agent to silanol groups on the surface of silica particles Concentration of silica particles: charge Content of silica particles / concentration of charge transport material with respect to the entire transport layer: content of charge transport material obtained by subtracting the mass of silica particles from the mass of all components of the charge transport layer (concentration of charge transport material = charge transport material) Mass / (total charge transport layer mass-silica particle mass))

  Hereinafter, the characteristics of each silica particle measured according to the above-described method are listed in Table 1, and details of each example and evaluation results are listed in Tables 2 to 7.

  From the above results, it can be seen that the dent and electrical characteristics of the inorganic protective layer are better in this example than in the comparative example.

210 Deposition chamber, 211 Exhaust port, 212 Substrate rotating unit, 213 Substrate support member, 214 Substrate, 215, 220 Gas introduction pipe, 216 Shower nozzle, 217 Plasma diffusion unit, 218 High frequency power supply unit, 219 Flat plate electrode, 221 High frequency Discharge tube section, 222 high frequency coil, 223 quartz tube, 10 electrophotographic photosensitive member, 10A electrophotographic photosensitive member, 10B electrophotographic photosensitive member, 20 charging device, 30 exposure device, 40 developing device, 41 developing container, 41A developing container body 41B Developing container cover, 41C Wall, 42 Developing roll, 42A Developing roll chamber, 43 Stirring member, 43A Stirring chamber, 44 Stirring member, 44A Stirring chamber, 45 Layer thickness regulating member, 46 Replenishment transport path, 47 Replenishing developer Storage container, 50 intermediate transfer member, 50A support roller, 50B support roller, 50C Rear roller, 50D Drive roller, 51 Primary transfer device, 52 Secondary transfer device, 53 Recording paper supply device, 53A Conveyance roller, 53B Induction slope, 54 Intermediate transfer member cleaning device, 70 Cleaning device, 71 Housing, 72 Cleaning Blade, 80 Fixing device, 81 Fixing roller, 82 Conveyor, 101 Image forming device, 101A Process cartridge

Claims (3)

  Hydrophobized silica particles having a volume average particle size of 20 nm to 200 nm and a condensation rate of 90% or more. The hydrophobized silica particles according to claim 1, wherein the hydrophobized silica particles have a volume resistivity of 10 ¹¹ Ω · cm or more.   The hydrophobized silica particle according to claim 1 or 2, wherein the hydrophobized silica particle is a silane compound having a trimethylsilyl group, a decylsilyl group, or a phenylsilyl group on the surface of the silica particle.