JP7043953B2 - Electrophotographic photoconductors, process cartridges, and image forming equipment - Google Patents

Description

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

Patent Document 1 describes a conductive substrate and an organic photosensitive layer provided on the conductive substrate, in which at least a charge transport material and a volume average particle size of 20 nm or more and 200 nm or less are formed in a region on the surface side in contact with the inorganic protective layer. Described is an electrophotographic photosensitive member comprising an organic photosensitive layer containing silica particles, and an inorganic protective layer provided on the organic photosensitive layer in contact with the surface thereof.

Patent Document 2 describes an electron having a substrate, an undercoat layer which is a vapor-filmed film containing oxygen and gallium and a gallium content of 28 atomic% or more and 40 atomic% or less in this order from the substrate side, and a photosensitive layer. A photographic photosensitive member is described.

Japanese Patent No. 5994708 Japanese Patent No. 5509764

For example, in an electrophotographic photosensitive member provided with an inorganic protective layer, a hard object such as a carrier migrates to the surface of the electrophotographic photosensitive member and intervenes between the electrophotographic photosensitive member and a member in contact with the electrophotographic photosensitive member. Therefore, dents may occur on the inorganic protective layer.

An object of the present invention is that in an electrophotographic photosensitive member provided with a single-layer type photosensitive layer and an inorganic protective layer, inorganic protection is compared with a case where the total thickness of the layers interposed between the conductive substrate and the inorganic protective layer exceeds 25 μm. It is an object of the present invention to provide an electrophotographic photosensitive member in which the generation of dents in a layer is suppressed.
Here, the "dent" generated in the inorganic protective layer is a circular or elliptical concave portion having a maximum diameter of 50 μm or less.

The above problem is solved by the following means.

<1> With a conductive substrate
A single-layer photosensitive layer provided on the conductive substrate, an inorganic protective layer provided on the single-layer photosensitive layer, and the like.
Have,
An electrophotographic photosensitive member having a total film thickness of 10 μm or more and 25 μm or less of a layer interposed between the conductive substrate and the inorganic protective layer.

<2> The electrophotographic photosensitive member according to <1>, wherein the single-layer type photosensitive layer contains a binder resin, a charge generating material, a hole transporting material, an electron transporting material, and silica particles.
<3> The electrophotographic photosensitive member according to <2>, wherein the content of the silica particles with respect to the single-layer type photosensitive layer is 40% by mass or more and 70% by mass or less.

<4> The ratio (A / B) of the film thickness A of the inorganic protective layer to the total film thickness B of the layer interposed between the conductive substrate and the inorganic protective layer is 0.12 or more. The electrophotographic photosensitive member according to any one of 1> to <3>.

<5> The electrophotographic photosensitive member according to any one of <1> to <4>, wherein the inorganic protective layer is an inorganic protective layer composed of a metal oxide layer containing a Group 13 element and oxygen.
<6> The electrophotographic photosensitive member according to <5>, wherein the metal oxide layer is a metal oxide layer containing gallium oxide.

<7> The electrophotographic photosensitive member according to any one of <1> to <6> is provided.
A process cartridge that can be attached to and detached from the image forming device.

<8> The electrophotographic photosensitive member according to any one of <1> to <6>.
A charging means for charging the surface of the electrophotographic photosensitive member and
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member,
A developing means for developing an electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image, and a developing means.
A transfer means for transferring the toner image to the surface of a recording medium,
An image forming apparatus.

According to the invention according to <1>, <5>, or <6>, the dents of the inorganic protective layer are compared with the case where the total film thickness of the layer interposed between the conductive substrate and the inorganic protective layer exceeds 25 μm. An electrophotographic photosensitive member in which the occurrence of the above is suppressed is provided.

According to the invention according to <2> or <3>, there is provided an electrophotographic photosensitive member in which the generation of dents in the inorganic protective layer is suppressed as compared with the case where the single-layer type photosensitive layer does not contain silica particles.

According to the invention according to <4>, there is provided an electrophotographic photosensitive member in which the generation of dents in the inorganic protective layer is suppressed as compared with the case where the ratio A / B is less than 0.12.

According to the invention according to <7> or <8>, the generation of dents in the inorganic protective layer is suppressed as compared with the case where the total film thickness of the layer interposed between the conductive substrate and the inorganic protective layer exceeds 25 μm. A process cartridge or image forming apparatus comprising the electrophotographic photosensitive member is provided.

It is a schematic cross-sectional view which shows an example of the layer structure of the electrophotographic photosensitive member of this embodiment. It is a schematic cross-sectional view which shows another example of the layer structure of the electrophotographic photosensitive member of this embodiment. It is a schematic schematic diagram which shows an example of the film forming apparatus used for forming the inorganic protective layer of the electrophotographic photosensitive member of this embodiment. It is a schematic schematic diagram which shows the example of the plasma generator used for forming the inorganic protective layer of the electrophotographic photosensitive member of this embodiment. It is a schematic block diagram which shows an example of the image forming apparatus which concerns on this embodiment. It is a schematic block diagram which shows another example of the image forming apparatus which concerns on this embodiment.

Hereinafter, embodiments of the present invention will be described in detail.
In the present specification, the "electrophotographic photosensitive member" may be simply referred to as a "photoreceptor".

[Electrophotophotoconductor]
The electrophotographic photosensitive member according to the present embodiment includes a conductive substrate, a single-layer type photosensitive layer provided on the conductive substrate, and an inorganic protective layer provided on the single-layer type photosensitive layer. It is an electrophotographic photosensitive member having a total thickness of 10 μm or more and 25 μm or less of the layers interposed between the conductive substrate and the inorganic protective layer.
Here, the layer interposed between the conductive substrate and the inorganic protective layer is an arbitrary layer such as an undercoat layer and an intermediate layer between the conductive substrate and the inorganic protective layer, in addition to the single-layer type photosensitive layer. If provided, it also includes any layer thereof.
The single-layer type photosensitive layer is a photosensitive layer composed of a single layer having a hole transporting ability and an electron transporting ability as well as a charge generating ability.

Here, conventionally, a technique for forming an inorganic protective layer on an organic photosensitive layer is known.
The organic photosensitive layer has flexibility and tends to be easily deformed, while the inorganic protective layer tends to be hard but inferior in toughness. Therefore, dents may occur on the inorganic protective layer.

For example, in the developing step, when carriers are scattered from the developing means and the scattered carriers adhere to the electrophotographic photosensitive member, the carriers reach the transfer position while adhering to the electrophotographic photosensitive member. Then, at the transfer position, the carrier is subjected to pressing pressure while being sandwiched between the electrophotographic photosensitive member and the transfer means. Therefore, for example, the carrier is pressed against the inorganic protective layer between the electrophotographic photosensitive member and the transfer means, and dents (dents) are generated in the inorganic protective layer.

Therefore, the present inventors have studied suppressing the generation of dents in the inorganic protective layer, and have found an electrophotographic photosensitive member having the following configuration.
That is, it is an electrophotographic photosensitive member having a single-layer type photosensitive layer and an inorganic protective layer in this order on a conductive substrate, and the total film thickness of the layers interposed between the conductive substrate and the inorganic protective layer is 10 μm or more and 25 μm. The following electrophotographic photosensitive member.
The conductive substrate and the inorganic protective layer have relatively high hardness due to the material (for example, the film elastic modulus is 30 GPa or more), whereas the layer interposed between the conductive substrate and the inorganic protective layer is simple. The hardness is low because it contains organic compounds, including the layered photosensitive layer.
In the electrophotographic photosensitive member according to the present embodiment, by reducing the film thickness of the low-hardness layer sandwiched between the high-hardness conductive substrate and the inorganic protective layer, the inorganic protective layer is locally stressed by a carrier or the like. Even when it is applied, it is considered that the hardness of the conductive substrate makes it easier to receive stress and suppresses the generation of dents in the inorganic protective layer.
That is, by reducing the proportion of low-hardness layers such as the single-layer photosensitive layer, which affects the generation of dents in the inorganic protective layer, among the layers provided on the conductive substrate, the inorganic layer is inorganic. It is possible to suppress the occurrence of dents on the protective layer.

From the above, it is presumed that in the electrophotographic photosensitive member according to the present embodiment, the generation of dents is suppressed by the above configuration.

In the electrophotographic photosensitive member according to the present embodiment, it is preferable that the single-layer type photosensitive layer contains a binder resin, a charge generating material, a hole transporting material, an electron transporting material, and silica particles.
The silica particles function as a reinforcing material in the single-layer type photosensitive layer, and can improve the film elastic modulus of the single-layer type photosensitive layer. Further, since the hardness of the single-layer type photosensitive layer, which is the lower layer, is increased, the generation of dents in the inorganic protective layer can be effectively suppressed.
Here, the content of the silica particles with respect to the single-layer type photosensitive layer is preferably 40% by mass or more and 70% by mass or less, more preferably 45% by mass or more and 70% by mass or less, and further preferably 50% by mass or more and 65% by mass or less. ..

Further, in the electrophotographic photosensitive member according to the present embodiment, the film thickness A of the inorganic protective layer is thick from the viewpoint of effectively suppressing the generation of dents in the inorganic protective layer, and the layer intervening between the inorganic protective layers is formed. It is desirable that the total film thickness B is thin, and the ratio (A / B) of the film thickness A of the inorganic protective layer to the total film thickness B of the layer interposed between the conductive substrate and the inorganic protective layer is 0.12. The above is preferable, 0.16 or more is more preferable, and 0.2 or more is further preferable.

In the electrophotographic photosensitive member according to the present embodiment, the ratio of the film thickness of the single-layer type photosensitive layer to the total film thickness B of the layer interposed between the conductive substrate and the inorganic protective layer is 50% to 100%. It is preferable, 90% to 100% is more preferable.

Here, a method for measuring the film thickness of each layer provided on the conductive substrate will be described.
A cross section of the electrophotographic photosensitive member is cut out, the cross section is photographed with an optical microscope (manufactured by KEYENCE, model number: VHX100), and the cross section is measured from the obtained cross section image.
From the cross-sectional image, measure the film thickness at any 5 points for the measurement target, obtain the average value, and use this as the film thickness.

Hereinafter, the electrophotographic photosensitive member according to this embodiment will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.
1 and 2 are schematic cross-sectional views showing an example of the layer structure of the electrophotographic photosensitive member according to the present embodiment.
In the photoconductor 7A shown in FIG. 1, a single-layer photosensitive layer 3 and an inorganic protective layer 4 are provided on the conductive substrate 1 in this order.
Further, in the photoconductor 7B shown in FIG. 2, the undercoat layer 2, the single-layer type photosensitive layer 3, and the inorganic protective layer 4 are provided on the conductive substrate 1 in this order.
An intermediate layer is provided as an arbitrary layer between the conductive substrate 1 and the single-layer photosensitive layer 3 in FIG. 1 or between the conductive substrate 1 and the undercoat layer 2 in FIG. May be good.
In the present embodiment, in the case of the photoconductor 7A shown in FIG. 1, the total film thickness of the layers interposed between the conductive substrate and the inorganic protective layer, that is, the film thickness of the single-layer photosensitive layer 3 is 10 μm or more and 25 μm. It is as follows.
Further, in the case of the photoconductor 7B shown in FIG. 2, the total film thickness of the layer interposed between the conductive substrate and the inorganic protective layer, that is, the total film thickness of the undercoat layer 2 and the single-layer type photosensitive layer 3 is 10 μm. It is 25 μm or less.

Hereinafter, each element constituting the electrophotographic photosensitive member will be described. The reference numerals may be omitted for description.

(Conductive hypokeimenon)
Examples of the conductive substrate include metal plates containing metals (aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.), metal drums, metal belts, and the like. Can be mentioned. The conductive substrate may be, for example, a paper, a resin film, a belt or the like coated, vapor-deposited or laminated with a conductive compound (for example, a conductive polymer, indium oxide, etc.), a metal (for example, aluminum, palladium, gold, etc.) or an alloy. Can also be mentioned. Here, "conductivity" means that the volume resistivity is less than 10 ¹³ Ωcm.

When the electrophotographic photosensitive member is used for a laser printer, the surface of the conductive substrate has a centerline average roughness Ra of 0.04 μm or more and 0.5 μm for the purpose of suppressing interference fringes generated when irradiating the laser beam. It is preferable that the surface is roughened below. When non-interfering light is used as a light source, roughening to prevent interference fringes is not particularly necessary, but it is suitable for longer life because it suppresses the occurrence of defects due to the unevenness of the surface of the conductive substrate.

As a method of roughening, for example, wet honing performed by suspending an abrasive in water and spraying it on a conductive substrate, centerless grinding in which the conductive substrate is pressed against a rotating grindstone and continuously ground. , Anodizing treatment and the like.

As a method of roughening, the conductive or semi-conductive powder is dispersed in the resin without roughening the surface of the conductive substrate to form a layer on the surface of the conductive substrate. Another method is to roughen the surface with particles dispersed in the layer.

In the roughening treatment by anodizing, an oxide film is formed on the surface of the conductive substrate by anodizing in an electrolyte solution using a conductive substrate made of metal (for example, made of aluminum) as an anode. Examples of the electrolyte solution include sulfuric acid solution, oxalic acid solution and the like. However, the porous anodized film formed by anodizing is chemically active as it is, is easily contaminated, and has a large resistance fluctuation depending on the environment. Therefore, for the porous anodic oxide film, the micropores of the oxide film are closed by volume expansion due to the hydration reaction in pressurized steam or boiling water (a metal salt such as nickel may be added), and more stable hydration oxidation is performed. It is preferable to perform a sealing treatment to change the material.

The film thickness of the anodizing film is preferably, for example, 0.3 μm or more and 15 μm or less. When this film thickness is within the above range, the barrier property against injection tends to be exhibited, and the increase in the residual potential due to repeated use tends to be suppressed.

The conductive substrate may be treated with an acidic treatment liquid or a boehmite treatment.
The treatment with the acidic treatment liquid is carried out, for example, as follows. First, an acidic treatment liquid containing phosphoric acid, chromic acid and hydrofluoric acid is prepared. The blending ratio of phosphoric acid, chromic acid and phosphoric acid in the acidic treatment liquid is, for example, a range of 10% by mass or more and 11% by mass or less of phosphoric acid, a range of 3% by mass or more and 5% by mass or less of chromic acid, and a hydrofluoric acid. It is preferably in the range of 0.5% by mass or more and 2% by mass or less, and the concentration of these acids as a whole is preferably in the range of 13.5% by mass or more and 18% by mass or less. The treatment temperature is preferably 42 ° C. or higher and 48 ° C. or lower, for example. The film thickness of the coating is preferably 0.3 μm or more and 15 μm or less.

The boehmite treatment is carried out, for example, by immersing in pure water at 90 ° C. or higher and 100 ° C. or lower for 5 to 60 minutes, or by contacting with heated steam at 90 ° C. or higher and 120 ° C. or lower for 5 to 60 minutes. The film thickness of the coating is preferably 0.1 μm or more and 5 μm or less. This can be further anodized with an electrolyte solution having low film solubility such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, and citrate. good.

(Single layer type photosensitive layer)
The single-layer photosensitive layer may be a single layer having a hole transporting ability and an electron transporting ability as well as a charge generating ability, and preferably, for example, a binder resin, a charge generating material, and an electron transporting material. , And a photosensitive layer containing a hole transporting material, more preferably a photosensitive layer containing a binder resin, a charge generating material, an electron transporting material, a hole transporting material, and silica particles.

-Bound resin-
Examples of the binder resin include polycarbonate resin, polyester resin, polyarylate resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, and vinylidene chloride. -Acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinyl Examples thereof include carbazole and polysilane. These binder resins may be used alone or in admixture of two or more.

Among these binder resins, polycarbonate resin and polyarylate resin are preferable from the viewpoint of mechanical strength of the single-layer type photosensitive layer.
Further, from the viewpoint of the film-forming property of the single-layer type photosensitive layer, it is preferable to use at least one of a polycarbonate resin having a viscosity average molecular weight of 30,000 or more and 80,000 or less, and a polyarylate resin having a viscosity average molecular weight of 30,000 or more and 80,000 or less.

The viscosity average molecular weight is a value measured by the following method. 1 g of the resin is dissolved in 100 cm ³ of methylene chloride, and the specific viscosity ηsp is measured with a Ubbelohde viscometer in a measurement environment of 25 ° C. Then, the ultimate viscosity [η] (cm ³ / g) was obtained from the relational expression of ηsp / c = [η] +0.45 [η] ² c (where c is the concentration (g / cm ³ )), and H.I. The viscosity average molecular weight Mv is obtained from the relational expression [η] = 1.23 × 10 ^-4 Mv ^0.83 given by Schnell.

The content of the binder resin with respect to the total solid content excluding silica particles in the single-layer photosensitive layer is, for example, 35% by mass or more and 60% by mass or less, preferably 40% by mass or more and 55% by mass or less.

-Charge generating material-
Examples of the charge generating material include azo pigments such as bisazo and trisazo; condensed ring aromatic pigments such as dibromoanthhrone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide; trigonal selenium and the like.

Among these, in order to correspond to laser exposure in the near infrared region, it is preferable to use a metal phthalocyanine pigment or a non-metal phthalocyanine pigment as the charge generating material. Specific examples thereof include hydroxygallium phthalocyanine; chlorogallium phthalocyanine; dichlorotin phthalocyanine; titanyl phthalocyanine.

On the other hand, in order to cope with laser exposure in the near-ultraviolet region, as a charge generating material, a condensed ring aromatic pigment such as dibromoanthanthrone; a thioindigo pigment; a porphyrazine compound; zinc oxide; a trigonal selenium; a bisazo pigment Etc. may be used.

That is, as the charge generating material, for example, when a light source having an exposure wavelength of 380 nm or more and 500 nm or less is used, an inorganic pigment is preferably used, and when a light source having an exposure wavelength of 700 nm or more and 800 nm or less is used, a metal or a metal-free material is used. Phthalocyanine pigments may be used.

Above all, as the charge generating material, it is desirable to use at least one selected from hydroxygallium phthalocyanine pigment and chlorogallium phthalocyanine pigment. As these charge generating materials, they may be used alone or in combination of two or more. Hydroxygallium phthalocyanine pigments are preferable from the viewpoint of increasing the sensitivity of the photoconductor.
When the hydroxygallium phthalocyanine pigment and the chlorogallium phthalocyanine pigment are used in combination, the ratio of the hydroxygallium phthalocyanine pigment to the chlorogallium phthalocyanine pigment is the mass ratio. It is preferably 3: 7 (preferably 9: 1 to 6: 4).

The hydroxygallium phthalocyanine pigment is not particularly limited, but a V-type hydroxygallium phthalocyanine pigment is preferable.
In particular, as the hydroxygallium phthalocyanine pigment, for example, in the spectral absorption spectrum in the wavelength range of 600 nm or more and 900 nm or less, the hydroxygallium phthalocyanine pigment having the maximum peak wavelength in the range of 810 nm or more and 839 nm or less can obtain more excellent dispersibility. Desirable from the point of view.

Further, it is preferable that the hydroxygallium phthalocyanine pigment having the maximum peak wavelength in the range of 810 nm or more and 839 nm or less has an average particle size in a specific range and a BET specific surface area in a specific range. Specifically, the average particle size is preferably 0.20 μm or less, and more preferably 0.01 μm or more and 0.15 μm or less. On the other hand, the BET specific surface area is preferably 45 m ² / g or more, more preferably 50 m ² / g or more, and further preferably 55 m ² / g or more and 120 m ² / g or less. The average particle size is a volume average particle size, which is a value measured by a laser diffraction / scattering type particle size distribution measuring device (LA-700, HORIBA, Ltd.). The BET specific surface area is a value measured by the nitrogen substitution method using a fluidized specific surface area automatic measuring device (Shimadzu Flow Soap II 2300).

The maximum particle size (maximum value of the primary particle size) of the hydroxygallium phthalocyanine pigment is preferably 1.2 μm or less, more preferably 1.0 μm or less, still more preferably 0.3 μm or less.

The hydroxygallium phthalocyanine pigment preferably has an average particle size of 0.2 μm or less, a maximum particle size of 1.2 μm or less, and a BET specific surface area of 45 m ² / g or more.

The hydroxygallium phthalocyanine pigment has a Bragg angle (2θ ± 0.2 °) of at least 7.3 °, 16.0 °, 24.9 °, and 28.0 ° in the X-ray diffraction spectrum using CuKα characteristic X-ray. It is preferably V-shaped having a diffraction peak.

On the other hand, the chlorogallium phthalocyanine pigment has Bragg angles (2θ ± 0.2 °) of 7.4 °, 16.6 °, 25.5 ° and 28.3 ° in terms of the sensitivity of the single-layer photosensitive layer. Compounds with diffraction peaks are preferred. The preferred ranges of maximum peak wavelength, average particle size, maximum particle size, and BET specific surface area of the chlorogallium phthalocyanine pigment are the same as those of the hydroxygallium phthalocyanine pigment.

As the charge generating material, one kind may be used alone, or two or more kinds may be used in combination.

The content of the charge generating material with respect to the total solid content excluding silica particles in the single-layer photosensitive layer is preferably 0.8% by mass or more and 5% by mass or less, preferably 0.8% by mass, from the viewpoint of suppressing density unevenness at the initial stage of image formation. % Or more and 4% by mass or less are more preferable, and 0.8% by mass or more and 3% by mass or less are further preferable.

-Hole transport material-
The hole transport material is not particularly limited, but is, for example, an oxadiazole derivative such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole; 1,3,5-tri Pyrazoline derivatives such as phenyl-pyrazolin, 1- [pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline; triphenylamine, N, N'-bis (3, Aromatic tertiary amino compounds such as 4-dimethylphenyl) biphenyl-4-amine, tri (p-methylphenyl) aminyl-4-amine, dibenzylaniline; N, N'-bis (3-methylphenyl)- Aromatic tertiary diamino compounds such as N, N'-diphenylbenzidine, 3- (4'-dimethylaminophenyl) -5,6-di- (4'-methoxyphenyl) -1,2,4-triazine, etc. 1,2,4-Triazine derivative; Hydrazone derivative such as 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone; Kinazoline derivative such as 2-phenyl-4-styryl-quinazoline; 6-Hydroxy-2,3-di ( P-benzofuran derivatives such as p-methoxyphenyl) benzofuran; α-stilben derivatives such as p- (2,2-diphenylvinyl) -N, N-diphenylaniline; enamine derivatives; carbazole derivatives such as N-ethylcarbazole; poly-N -Vinylcarbazole and derivatives thereof; a polymer having a group composed of the above-mentioned compound in the main chain or the side chain; and the like. These hole transporting materials may be used alone or in combination of two or more.

Specific examples of the hole transport material include a compound represented by the following general formula (HT1) and a compound represented by the following general formula (HT2). Further, a compound represented by the following general formula (1) can be mentioned. Among these, from the viewpoint of charge mobility, it is preferable to apply the compound represented by the following general formula (1).

In the general formula (HT1), ^RH1 represents a hydrogen atom or a methyl group. n11 indicates 1 or 2. Ar ^H1 and Ar ^H2 are independently substituted or unsubstituted aryl groups, -C ₆ H ₄ -C ( ^RH3 ) = C ( ^RH4 ) ( ^RH5 ), or -C ₆ H ₄ -CH = CH- CH = C ( ^{RH6) (RH7), where RH3 to RH7 independently represent a} hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, respectively. Examples of the substituent include a halogen atom, an alkyl group having 1 or more and 5 or less carbon atoms, an alkoxy group having 1 or more and 5 or less carbon atoms, or a substituted amino group substituted with an alkyl group having 1 or more and 3 or less carbon atoms.

In the general formula (H2), R ^H81 and R ^H82 may be the same or different, and each independently contains a hydrogen atom, a halogen atom, an alkyl group having 1 or more and 5 or less carbon atoms, and an alkoxy group having 1 or more carbon atoms and 5 or less carbon atoms. show. ^RH91 , ^RH92 , ^RH101 , and ^RH102 may be the same or different, and each independently has a halogen atom, an alkyl group having 1 or more and 5 or less carbon atoms, an alkoxy group having 1 or more carbon atoms and 5 or less carbon atoms, and 1 or more carbon atoms. Amino group substituted with 2 or less alkyl group, substituted or unsubstituted aryl group, -C ( ^RH11 ) = C ( ^RH12 ) ( ^RH13 ), or -CH = CH-CH = C ( ^RH14 ). ( ^RH15 ) is shown, and ^RH11 to ^RH15 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. m12, m13, n12 and n13 each independently indicate an integer of 0 or more and 2 or less.

Here, among the compound represented by the general formula (HT1) and the compound represented by the general formula (HT2), in particular, "-C ₆ H ₄ -CH = CH-CH = C ( ^{RH6) (RH7 )} ". The compound represented by the general formula (HT1) and the compound represented by the general formula (HT2) having "-CH = CH-CH = C ( ^RH14 ) ( ^RH15 )" are preferable.

Hereinafter, specific examples of the compound represented by the general formula (HT1) and the compound represented by the general formula (HT2) include the following structural formulas (HT-A) to (HT-G). It is not limited to these.

Next, the compound represented by the general formula (1) will be described.

In the general formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are independently hydrogen atom, lower alkyl group, alkoxy group, phenoxy group, halogen atom, or lower. A phenyl group which may have a substituent selected from an alkyl group, a lower alkoxy group and a halogen atom is shown. m and n independently represent 0 or 1, respectively.

In the general formula (1), examples of the lower alkyl groups represented by R ¹ to R ⁶ include linear or branched alkyl groups having 1 or more and 4 or less carbon atoms, and specific examples thereof include, for example. Examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group and an isobutyl group.
Among these, as the lower alkyl group, a methyl group and an ethyl group are preferable.

In the general formula (1), examples of the alkoxy group represented by R ¹ to R ⁶ include an alkoxy group having 1 or more carbon atoms and 4 or less carbon atoms, and specifically, a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. And so on.

In the general formula (1), examples of the halogen atom represented by R ¹ to R ⁶ include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.

In the general formula (1), examples of the phenyl group represented by R ¹ to R ⁶ include an unsubstituted phenyl group; a lower alkyl group substituted phenyl group such as a p-tolyl group and a 2,4-dimethylphenyl group; p. -A phenyl group substituted with a lower alkoxy group such as a methoxyphenyl group; a phenyl group substituted with a halogen atom such as a p-chlorophenyl group and the like can be mentioned.
Examples of the substituent that can be substituted with the phenyl group include a lower alkyl group represented by R ¹ to R ⁶ , a lower alkoxy group, and a halogen atom.

Among the compounds represented by the general formula (1), hole transport materials in which m and n are 1 are preferable from the viewpoint of high sensitivity, and R ¹ to R ⁶ are independently hydrogen atoms and carbon atoms 1. A hole transport material showing a lower alkyl group of 4 or less or an alkoxy group and in which m and n are 1 is more preferable.

Hereinafter, compounds (1-1) to (1-64) are given as examples of the compound represented by the general formula (1), but the present invention is not limited thereto. The number in front of the substituent indicates the position of substitution with respect to the benzene ring.

The abbreviations in the above exemplified compounds have the following meanings.
-4-Me: Methyl group substituted at the 4-position of the phenyl group-3-Me: Methyl group substituted at the 3-position of the phenyl group-4-Cl: Chlorine atom substituted at the 4-position of the phenyl group-4 -MeO: methoxy group substituted at the 4-position of the phenyl group, 4-F: fluorine atom substituted at the 4-position of the phenyl group, 4-Pr: propyl group substituted at the 4-position of the phenyl group, 4-PhO : A phenoxy group that replaces the 4-position of the phenyl group

<Electron transport material>
The electron transport material is not particularly limited, but for example, quinone compounds such as chloranyl and bromoanyl; tetracyanoquinodimethane compounds; 2,4,7-trinitro-9-fluorenone, 2,4,5,7. -Fluolenone compounds such as tetranitro-9-fluorenone, 9-dicyanomethylene-9-fluorenone-4-carboxylate octyl; 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3. Oxa such as 4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4-oxadiazole, 2,5-bis (4-diethylaminophenyl) 1,3,4-oxadiazole, etc. Diazole-based compounds; Xantone-based compounds; Thiophene-based compounds; Dinaftquinone-based compounds such as 3,3'-di-tert-pentyl-dinaphthoquinone;3,3'-di-tert-butyl-5,5'-dimethyl Diphenoquinone compounds such as diphenoquinone, 3,3', 5,5'-tetra-tert-butyl-4,4'-diphenoquinone; a polymer having a group composed of the above compounds in the main chain or side chain. ; And so on. These electron transport materials may be used alone or in combination of two or more.

As the electron transport material, a compound represented by the following general formula (2) is preferable from the viewpoint of high sensitivity.

In the general formula (2), R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ are independently hydrogen atoms, halogen atoms, alkyl groups, alkoxy groups, aryl groups, or R 17s, respectively. Indicates an Aralkyl group. R ¹⁸ represents an alkyl group, —L ¹⁹ -OR ²⁰ , an aryl group, or an aralkyl group. However, L ¹⁹ represents an alkylene group and R ²⁰ represents an alkyl group.

In the general formula (2), examples of the halogen atom represented by R ¹¹ to R ¹⁷ include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.

In the general formula (2), examples of the alkyl group represented by R ¹¹ to R ¹⁷ include linear or branched alkyl groups having 1 or more and 4 or less carbon atoms (preferably 1 or more and 3 or less). Specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group and the like.

In the general formula (2), examples of the alkoxy group represented by R ¹¹ to R ¹⁷ include an alkoxy group having 1 or more and 4 or less carbon atoms (preferably 1 or more and 3 or less), and specifically, a methoxy group. Examples thereof include an ethoxy group, a propoxy group and a butoxy group.

In the general formula (2), examples of the aryl group represented by R ¹¹ to R ¹⁷ include a phenyl group and a tolyl group. Among these, the phenyl group is preferable as the aryl group indicated by R ¹¹ to R ¹⁷ .
In the general formula (2), examples of the aralkyl group represented by R ¹¹ to R ¹⁷ include a benzyl group, a phenethyl group, a phenylpropyl group and the like.

In the general formula (2), examples of the alkyl group represented by R ¹⁸ include a linear alkyl group having 1 or more and 12 or less carbon atoms (preferably 5 or more and 10 or less carbon atoms) and 3 or more and 10 or less carbon atoms (preferably). Is a branched alkyl group having 5 or more and 10 or less carbon atoms.
Examples of the linear alkyl group having 1 or more and 12 or less carbon atoms include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group and n. -Includes octyl group, n-nonyl group, n-decyl, n-undecyl, n-dodecyl group and the like.
Examples of the branched alkyl group having 3 or more carbon atoms and 10 or less carbon atoms include an isopropyl group.
Isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, neopentyl group, tert-pentyl group, isohexyl group, sec-hexyl group, tert-hexyl group, isoheptyl group, sec-heptyl group, tert-heptyl group, Examples thereof include an isooctyl group, a sec-octyl group, a tert-octyl group, an isononyl group, a sec-nonyl group, a tert-nonyl group, an isodecyl group, a sec-decyl group and a tert-decyl group.

In the general formula (2), in the group represented by -L ¹⁹ -OR ²⁰ represented by R ¹⁸ , L ¹⁹ represents an alkylene group and R ²⁰ represents an alkyl group.
Examples of the alkylene group indicated by L ¹⁹ include a linear or branched alkylene group having 1 or more and 12 or less carbon atoms, such as a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, and an isobutylene. Examples thereof include a group, a sec-butylene group, a tert-butylene group, an n-pentylene group, an isopentylene group, a neopentylene group, a tert-pentylene group and the like.
Examples of the alkyl group indicated by R ²⁰ include the same groups as the alkyl groups indicated by R ¹¹ to R ¹⁷ above.

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

In the general formula (2), examples of the aralkyl group represented by R ¹⁸ include a group represented by -L ²¹ -Ar. However, L ²¹ indicates an alkylene group, and Ar indicates an aryl group.
Examples of the alkylene group indicated by L ²¹ include a linear or branched alkylene group having 1 or more and 12 or less carbon atoms, such as a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, and an isobutylene. Examples thereof include a group, a sec-butylene group, a tert-butylene group, an n-pentylene group, an isopentylene group, a neopentylene group, a tert-pentylene group and the like.
Examples of the aryl group indicated by Ar include a phenyl group, a methylphenyl group, a dimethylphenyl group, an ethylphenyl group and the like.

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

As the electron transport material of the general formula (2), an electron transport material in which R ¹⁸ exhibits an alkyl group or an aralkyl group having 5 or more and 10 or less carbon atoms is preferable from the viewpoint of high sensitivity, and R ¹¹ to R ¹⁷ are particularly preferable. An electron transporting material that independently exhibits a hydrogen atom, a halogen atom, or an alkyl group and has an R ¹⁸ having 5 or more and 10 or less carbon atoms and an alkyl group or an aralkyl group is preferable.

Hereinafter, exemplary compounds of the electron transport material of the general formula (2) will be shown, but the present invention is not limited thereto. In addition, the following example compound number is referred to as an example compound (2-number) below. Specifically, for example, Exemplified Compound 15 is hereinafter referred to as "Exemplified Compound (2-15)".

The abbreviations in the above exemplified compounds have the following meanings.
・ Ph: Phenyl group

Specific examples of the electron transporting material include, in addition to the electron transporting material represented by the general formula (2), other electron transporting materials, for example, represented by the following structural formulas (ET-A) to (ET-E). Also mentioned are compounds.

The electron transport material of the general formula (2) may be used alone or in combination of two or more. When the electron transport material represented by the general formula (2) is used, the electron transport material represented by the general formula (2) and the electron transport material other than the electron transport material represented by the general formula (2) ( For example, the electron transport material of the compound represented by the above structural formulas (ET-A) to (ET-E) may be used in combination.
The content of the electron transport material other than the electron transport material represented by the general formula (2) is preferably in the range of 10% by mass or less with respect to the entire electron transport material.

The content of the total electron transport material with respect to the total solid content excluding silica particles in the single-layer photosensitive layer is preferably 4% by mass or more and 30% by mass or less, preferably 6% by mass or more and 20% by mass or less.

-Mass ratio of hole transport material and electron transport material-
The ratio of the hole transport material to the electron transport material is preferably 50/50 or more and 90/10 or less, and more preferably 60/40 or more and 80/20 or less in terms of mass ratio (hole transport material / electron transport material).

-Silica particles-
Examples of the silica particles include dry silica particles and wet silica particles.
Examples of the dry silica particles include combustion method silica (hummed silica) obtained by burning a silane compound and explosive combustion method silica obtained by explosively burning metallic silicon powder.
Wet silica particles include wet silica particles obtained by a neutralization reaction between sodium silicate and mineral acid (precipitation silica particles synthesized / aggregated under alkaline conditions, gel silica particles synthesized / aggregated under acidic conditions), and acidic silicic acid. Examples thereof include colloidal silica particles (silica sol particles) obtained by making them alkaline and polymerizing them, and sol-gel process silica particles obtained by hydrolysis of an organic silane compound (for example, alkoxysilane).
Among these, silica particles have few silanol groups on the surface and have a low void structure from the viewpoint of suppressing image defects due to generation of residual potential and deterioration of other electrical characteristics (suppression of deterioration of fine line reproducibility). Method It is preferable to use silica particles.

The volume average particle size of the silica particles is, for example, preferably 20 nm or more and 200 nm or less. The lower limit of the volume average particle size of the silica particles may be 40 nm or more, or 50 nm or more. The lower limit of the volume average particle size of the silica particles may be 150 nm or less, 120 nm or less, or 110 nm or less.

For the volume average particle size of the silica particles, the silica particles are separated from the layer, 100 primary particles of the silica particles are observed at a magnification of 40,000 times by an SEM (Scanning Electron Microsphere) device, and the particles are analyzed by image analysis of the primary particles. The longest diameter and the shortest diameter of each are measured, and the equivalent diameter of the sphere is measured from this 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 may be surface-treated with a hydrophobizing agent. As a result, the silanol groups on the surface of the silica particles are reduced, and the generation of residual potential is easily suppressed.
Examples of the hydrophobizing agent include well-known silane compounds such as chlorosilane, alkoxysilane, and silazane.
Among these, as the hydrophobizing treatment agent, a silane compound having a trimethylsilyl group, a decylsilyl group, or a phenylsilyl group is preferable from the viewpoint of facilitating the suppression of the generation of residual potential. That is, the surface of the silica particles may have 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, decyldimethylchlorosilane, and decyltrimethoxysilane.
Examples of the silane compound having a phenyl group include triphenylmethoxysilane and triphenylchlorosilane.

The condensation rate of the hydrophobized silica particles (the rate of Si—O—Si in the bond of SiO _4- in the silica particles: hereinafter also referred to as “condensation rate of the hydrophobizing agent”) is, for example, the surface of the silica particles. 90% or more is preferable, 91% or more is preferable, and 95% or more is more preferable with respect to the silanol group of.
When the condensation rate of the hydrophobizing agent is within the above range, the silanol groups of the silica particles are further reduced, and the generation of residual potential is easily suppressed.

The condensation rate of the hydrophobizing agent indicates the ratio of condensed silicon to the fully bondable site of silicon in the condensed portion detected by NMR, and is measured as follows.
First, the silica particles are separated from the layer. The separated silica particles were subjected to Si CP / MAS NMR analysis with Bruker's AVANCE III 400 to determine the peak area according to the number of SiO substitutions, and two substitutions (Si (OH) ₂ (0-Si) ₂ ) were obtained, respectively. -), 3-substitution (Si (OH) (0-Si) _3- ), 4-substitution (Si (0-Si) _4- ) values are set to Q2, Q3, Q4, and the condensation rate of the hydrophobic treatment agent is the 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, preferably 10 ¹² Ω cm or more, and more preferably 10 ¹³ Ω cm or more.
When the volume resistivity of the silica particles is set in the above range, the deterioration of the electrical characteristics 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, the silica particles are separated from the layer. Then, the separated silica particles to be measured are placed on the surface of a circular jig on which a 20 cm ² electrode plate is arranged so as to have a thickness of about 1 mm or more and 3 mm or less to form a silica particle layer. The same 20 cm ² electrode plate as described above is placed on this, and the silica particle layer is sandwiched therein. In order to eliminate the 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 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 volume resistivity (Ωcm) of the silica particles is calculated by reading the current value (A) flowing at this time. The formula for calculating the volume resistivity (Ωcm) of silica particles is as shown in the following formula.
In the formula, ρ is the volume resistivity (Ωcm) of the silica particles, E is the applied voltage (V), I is the current value (A), I ₀ is the current value (A) at the applied voltage 0V, and L is the silica particles. Represents the thickness (cm) of each layer. In this evaluation, the volume resistivity when the applied voltage is 1000 V was used.
-Formula: ρ = E × 20 / (I-I ₀ ) / L

The silica particles contained in the single-layer type photosensitive layer may be one type or a mixture of two or more types.
The content of silica particles with respect to the total solid content of the single-layer photosensitive layer is as described above.

-Other additives-
The single-layer photosensitive layer may contain known additives such as antioxidants, light stabilizers, heat stabilizers, fluororesin particles, and silicone oils.

-Film elastic modulus of single-layer photosensitive layer-
The film elastic modulus of the single-layer type photosensitive layer is preferably 5 GPa or more, and more preferably 8 GPa or more, from the viewpoint of suppressing the generation of dents in the inorganic protective layer.
In order to keep the elastic modulus of the single-layer photosensitive 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 each component other than silica particles can be mentioned. Be done.
The method for measuring the film elastic modulus of the single-layer type photosensitive layer will be described later.

-Film thickness of single-layer photosensitive layer-
The thickness of the single-layer photosensitive layer is preferably set in the range of 10 μm or more and 25 μm or less, more preferably 15 μm or more and 25 μm or less, and further preferably 20 μm or more and 25 μm or less.

-Formation of a single-layer photosensitive layer-
The single-layer type photosensitive layer is formed by using a coating liquid for forming a photosensitive layer in which the above components are added to a solvent.
Solvents include aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, halogenated aliphatic hydrocarbons such as methylene chloride, chloroform and ethylene chloride, tetrahydrofuran and ethyl ether. Examples thereof include ordinary organic solvents such as cyclic or linear ethers such as. These solvents may be used alone or in admixture of two or more.

As a method of dispersing particles (for example, silica particles and a charge generating material) in the coating liquid for forming a photosensitive layer, a media disperser such as a ball mill, a vibrating ball mill, an attritor, a sand mill, or a horizontal sand mill, a stirrer, or an ultrasonic disperser , Roll mills, high pressure homogenizers and other medialess dispersers are used. Examples of the high-pressure homogenizer include a collision method in which a dispersion liquid is dispersed by a liquid-liquid collision or a liquid-wall collision in a high-pressure state, and a penetration method in which a dispersion is dispersed by penetrating a fine flow path in a high-pressure state.

Examples of the method for applying the coating liquid for forming the photosensitive layer include a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, and a curtain coating method.

(Inorganic protective layer)
The inorganic protective layer may be a layer containing an inorganic material, and is preferably made of a metal oxide layer from the viewpoint of mechanical strength.
Here, the metal oxide layer refers to a layered material of a metal oxide (for example, a CVD film of a metal oxide, a vapor deposition film of a metal oxide, a sputter film of a metal oxide, etc.), and is a coagulation of metal oxide particles. Aggregates or aggregates are excluded.

-Composition of inorganic protective layer-
As the inorganic protective layer made of a metal oxide layer, a metal oxide layer made of a metal oxide containing a Group 13 element and oxygen is preferable because it is excellent in mechanical strength, translucency, and conductivity.
Examples of the metal oxide containing a Group 13 element and oxygen include metal oxides such as gallium oxide, aluminum oxide, indium oxide, and boron oxide, or mixed crystals thereof.
Among these, the metal oxide containing a Group 13 element and oxygen is particularly excellent in mechanical strength and translucency, particularly n-type conductivity, and is particularly oxidized from the viewpoint of excellent conductivity controllability. Gallium is preferred.
That is, the inorganic protective layer is preferably an inorganic protective layer made of a metal oxide layer containing gallium oxide.

The inorganic protective layer made of a metal oxide layer may be composed of, for example, a Group 13 element (preferably gallium) and oxygen, and may be composed of hydrogen and carbon, if necessary. good.
Since the inorganic protective layer made of a metal oxide layer contains hydrogen, various physical properties of the inorganic protective layer made of a metal oxide layer composed of a group 13 element (preferably gallium) and oxygen can be easily obtained. It becomes easier to control. For example, in an inorganic protective layer composed of a metal oxide layer containing gallium, oxygen, and hydrogen (for example, an inorganic protective layer composed of gallium oxide containing hydrogen), the composition ratio [O] / [Ga] is 1. By changing from 0 to 1.5, it becomes easier to control the volume resistivity in the range of ^{109 Ω · cm or more and 10 14 Ω} · cm.

In particular, the inorganic protective layer made of a metal oxide layer contains Group 13 elements, oxygen, and hydrogen, and the element composition ratio of Group 13 elements, oxygen, and hydrogen to all the elements constituting the inorganic protective layer. The sum is preferably 90 atomic% or more.
Further, the film elastic modulus can be easily controlled by changing the element composition ratio (oxygen / Group 13 element) of oxygen and the Group 13 element. In the element composition ratio of oxygen and Group 13 elements (oxygen / Group 13 elements), the higher the oxygen composition ratio, the higher the film elastic modulus tends to be, for example, 1.0 or more and less than 1.5. Is preferable, 1.03 or more and 1.47 or less is more preferable, 1.05 or more and 1.45 or less is further preferable, and 1.10 or more and 1.40 or less is particularly preferable.
When the element composition ratio (oxygen / Group 13 element) of the material constituting the inorganic protective layer composed of the metal oxide layer is within the above range, image defects caused by scratches on the surface of the photoconductor are suppressed, and photosensitivity is suppressed. The affinity with the fatty acid metal salt supplied to the body surface is improved, and the contamination inside the device by the fatty acid metal salt is suppressed. In the same respect, the Group 13 element is preferably gallium.

Further, the sum of the element composition ratios of the group 13 elements (particularly gallium), oxygen, and hydrogen with respect to all the elements constituting the inorganic protective layer composed of the metal oxide layer is 90 atomic% or more, for example. When Group 15 elements such as N, P, and As are mixed, the influence of these elements binding to Group 13 elements (particularly gallium) is suppressed, and oxygen and electrical properties that can improve the hardness and electrical properties of the inorganic protective layer are suppressed. It becomes easy to find an appropriate range of the group 13 element (particularly gallium) composition ratio (oxygen / group 13 element (particularly gallium)). From the above viewpoint, the sum of the elemental composition ratios is preferably 95 atomic% or more, more preferably 96 atomic% or more, and further preferably 97 atomic% or more.

In addition to the above-mentioned Group 13 elements, oxygen, hydrogen and carbon, the inorganic protective layer made of the metal oxide layer may contain other elements for controlling the conductive type.
In the case of n-type, the inorganic protective layer made of a metal oxide layer may contain one or more elements selected from C, Si, Ge, and Sn in the case of n-type, and in the case of p-type, the inorganic protective layer may contain one or more elements selected from C, Si, Ge, and Sn for controlling the conductive type. , N, Be, Mg, Ca, Sr may contain one or more elements selected from.

Here, when the inorganic protective layer made of a metal oxide layer contains gallium, oxygen, and hydrogen if necessary, it is excellent in mechanical strength, translucency, flexibility, and its conductivity controllability. From the viewpoint of superiority, suitable element composition ratios are as follows.
The elemental composition ratio of gallium is, for example, preferably 15 atomic% or more and 50 atomic% or less, more preferably 20 atomic% or more and 40 atomic% or less, and 20 It is more preferably atomic% or more and 30 atomic% or less.
The elemental composition ratio of oxygen is, for example, preferably 30 atomic% or more and 70 atomic% or less, more preferably 40 atomic% or more and 60 atomic% or less, more preferably 45, with respect to all the constituent elements of the inorganic protective layer. It is more preferably atomic% or more and 55 atomic% or less.
The elemental composition ratio of hydrogen is, for example, preferably 10 atomic% or more and 40 atomic% or less, more preferably 15 atomic% or more and 35 atomic% or less, and 20 It is more preferably atomic% or more and 30 atomic% or less.

Here, the confirmation of each element in the inorganic protective layer, the element composition ratio, the atomic number ratio, etc. are obtained by Rutherford backscattering (hereinafter referred to as "RBS") including the distribution in the thickness direction. 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 HYPRA program of CE & A is used for the analysis.
The measurement conditions of RBS are that the He ++ ion beam energy is 2.275 eV, the detection angle is 160 °, and the Glazing Angle is about 109 ° with respect to the incident beam.

Specifically, the RBS measurement is performed as follows. First, the He ++ ion beam is incident perpendicular to the sample, the detector is set at 160 ° with respect to the ion beam, and the backscattered He signal. To measure. The composition ratio and film thickness are determined from the detected He energy and intensity. The spectrum may be measured at two detection angles in order to improve the accuracy of determining the composition ratio and the film thickness. Accuracy is improved by measuring and cross-checking at two detection angles with different depth direction resolution and backscattering mechanics.
The number of He atoms scattered backward 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. The density is assumed by calculation from the measured composition, and the thickness is calculated using this. The density error is within 20%.

The elemental composition ratio of hydrogen is determined by hydrogen forward scattering (hereinafter referred to as "HFS").
In the 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 HYPRA program of CE & A is used for the analysis. The measurement conditions for HFS are as follows.
-He ++ ion beam energy: 2.275 eV
-Detection angle: Grazing Angle 30 ° for an incident beam of 160 °

The HFS measurement picks up the signal of hydrogen 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, it is preferable to cover the detector with aluminum foil to remove He atoms scattered together with hydrogen. Quantification is performed by normalizing the hydrogen counts of the reference sample and the sample under test by stopping power and then comparing them. As a reference sample, a sample in which H is ion-implanted into Si and muscovite are used.
Muscovite is known to have a hydrogen concentration of 6.5 atomic%.
The H adsorbed on the outermost surface is corrected, for example, by subtracting the amount of H adsorbed on the clean Si surface.

The inorganic protective layer made of a metal oxide layer may have a composition ratio distribution in the thickness direction or may have a multi-layer structure, depending on the purpose. ..

-Physical characteristics of the inorganic protective layer-
The surface roughness Ra (arithmetic mean surface roughness Ra) on the outer peripheral surface of the inorganic protective layer made of the metal oxide layer (that is, the surface of the electrophotographic photosensitive member 7A or 7B) is, for example, 5 nm or less, and is preferable. It is 4.5 nm or less, more preferably 4 nm or less.
By setting this surface roughness Ra within the above range, uneven charging is suppressed.
In addition, in order to set the surface roughness Ra in the above range, for example, a method such as setting the surface roughness Ra of the surface on the inorganic protective layer side in the charge transport layer to the above range can be mentioned. Further, the outer periphery of the inorganic protective layer can be set. The measurement of the surface roughness Ra on the surface is the same as the above-mentioned method for measuring the surface roughness Ra of the surface on the inorganic protective layer side in the charge transport layer, except that the outer peripheral surface of the inorganic protective layer is directly measured.

The volume resistivity of the inorganic protective layer made of the metal oxide layer is preferably 5.0 × 10 ⁷ Ωcm or more and less than 1.0 × 10 ¹² Ωcm. The volume resistivity of the inorganic protective layer makes it easier to suppress the generation of image flow and makes it easier to suppress image defects caused by scratches ^on the surface of the photoconductor. It is more preferably 0 × 10 ¹¹ Ωcm or less, further preferably 1.0 × 10 ⁸ Ωcm or more and 5.0 × 10 ¹¹ Ωcm or less, and particularly preferably 5.0 × 10 ⁸ Ωcm or more and 2.0 × 10 ¹¹ Ωcm or less.

This volume resistivity is calculated from the resistance values measured under the conditions of a frequency of 1 kHz and a voltage of 1 V using an LCR meter ZM2371 manufactured by nF, based on the electrode area and the sample thickness.
The measurement sample is a sample obtained by forming a film on an aluminum substrate under the same conditions as when forming the inorganic protective layer to be measured, and forming a gold electrode on the film by vacuum vapor deposition. Alternatively, the sample may be a sample in which the inorganic protective layer is peeled off from the electrophotographic photosensitive member after production, partially etched, and sandwiched between a pair of electrodes.

The inorganic protective layer made of a metal oxide 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 preferable in terms of surface smoothness, but microcrystalline film is more preferable in terms of hardness.
The growth cross section of the inorganic protective layer may have a columnar structure, but from the viewpoint of slipperiness, a structure with high flatness is preferable, and amorphous is preferable.
The crystallinity and amorphousness are determined by the presence or absence of points or lines in the diffraction image obtained by RHEED (reflection high-energy electron diffraction) measurement.

The film elastic modulus of the inorganic protective layer made of the metal oxide layer is more preferably 30 GPa or more and 80 GPa or less, and further preferably 40 GPa or more and 65 GPa or less.
When this elastic modulus is within the above range, the generation, peeling, and cracking of recesses (scratches) in the inorganic protective layer are likely to be suppressed.
A method for measuring the film elastic modulus of the inorganic protective layer made of a metal oxide layer will be described later.

The film thickness of the inorganic protective layer is, for example, preferably 1.0 μm or more and 10.0 μm or less, and more preferably 3.0 μm or more and 10 μm or less.
When this film thickness is within the above range, the generation, peeling, and cracking of recesses (scratches) in the inorganic protective layer are likely to be suppressed.

-Formation of inorganic protective layer-
For the formation of the protective layer, for example, known vapor deposition methods such as plasma CVD (Chemical Vapor Deposition) method, metalorganic vapor phase growth method, molecular beam epitaxy method, thin film deposition, and sputtering are used.

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. The following description describes a method for forming an inorganic protective layer containing gallium, oxygen, and hydrogen, but the present invention is not limited to this, and a well-known forming method is used depending on the composition of the target inorganic protective layer. Should be applied.

FIG. 3 is a schematic schematic view 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. 3A is a case where the film forming apparatus is viewed from the side. 3 (B) shows a schematic cross-sectional view between A1 and A2 of the film forming apparatus shown in FIG. 3 (A). In FIG. 3, 210 is a film forming chamber, 211 is an exhaust port, 212 is a base rotating part, 213 is a base support member, 214 is a base, 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 section, 218 is a high frequency power supply section, 219 is a flat plate electrode, 220 is a gas introduction tube, and 221 is a high frequency discharge tube section.

In the film forming apparatus shown in FIG. 3, 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 where the exhaust port 211 of the film forming chamber 210 is provided. On the opposite side, a plasma generator including a high-frequency power supply unit 218, a flat plate electrode 219, and a high-frequency discharge tube unit 221 is provided.
This plasma generator is arranged inside a high-frequency discharge tube section 221 and a high-frequency discharge tube section 221 and has a flat plate electrode 219 having a discharge surface provided on the exhaust port 211 side and a flat plate outside the high-frequency discharge tube section 221. It is composed of a high frequency power supply unit 218 connected to a surface opposite to the discharge surface of the electrode 219. A gas introduction pipe 220 for supplying gas into the high frequency discharge pipe 221 is connected to the high frequency discharge pipe portion 221, and the other end of the gas introduction pipe 220 is a first not shown (not shown). It is connected to the gas source of.

The plasma generator shown in FIG. 4 may be used instead of the plasma generator provided in the film forming apparatus shown in FIG. FIG. 4 is a schematic schematic view showing another example of the plasma generator used in the film forming apparatus shown in FIG. 3, and is a side view of the plasma generator. In FIG. 4, 222 represents a high frequency coil, 223 represents 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. 4). It is connected. Further, 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. 3, 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 the gas introduction pipe 215, and this gas is connected. The introduction pipe 215 is connected to a second gas supply source (not shown) provided outside the film forming chamber 210.
Further, a substrate rotating portion 212 is provided in the film forming chamber 210, and the substrate support member is provided so that the cylindrical substrate 214 faces the longitudinal direction of the shower nozzle 216 and the axial direction of the substrate 214. It can be attached to the substrate rotating portion 212 via 213. During film formation, the substrate 214 rotates in the circumferential direction due to the rotation of the substrate rotating portion 212. As the substrate 214, a laminate for manufacturing a photoconductor on which a single-layer type photosensitive layer is formed is used.

The formation of the inorganic protective layer is carried out, for example, as follows.
First, oxygen gas (or helium (He) diluted oxygen gas), helium (He) gas, and, if necessary, hydrogen (H ₂ ) gas are introduced from the gas introduction tube 220 into the high-frequency discharge tube section 221. A 13.56 MHz radio wave is supplied from the high frequency power supply unit 218 to the flat plate electrode 219. At this time, the plasma diffusion portion 217 is formed so as to radiate from the discharge surface side of the flat 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 flat plate electrode 219 side to the exhaust port 211 side. The flat plate electrode 219 may be a flat plate electrode 219 in which the electrode is surrounded by an earth shield.

Next, by introducing trimethylgallium gas into the film forming chamber 210 via the gas introduction tube 215 and the shower nozzle 216 located on the downstream side of the flat plate electrode 219 which is the activating means, gallium and oxygen are added to the surface of the substrate 214. A non-single crystal film containing hydrogen is formed.
As the substrate 214, a laminate for manufacturing a photoconductor on which a single-layer type photosensitive layer is formed is used.

Since the substrate 214 has a single-layer photosensitive layer, the temperature of the surface of the substrate 214 at the time of forming the inorganic protective layer is preferably 150 ° C. or lower, more preferably 100 ° C. or lower, still more preferably 30 ° C. or higher and 100 ° C. or lower.
Even if the temperature of the surface of the substrate 214 is 150 ° C or lower at the beginning of film formation, if the temperature rises above 150 ° C due to the influence of plasma, the single-layer photosensitive layer may be damaged by heat. It is preferable to control the surface temperature of the substrate 214 in consideration.
The temperature of the surface of the substrate 214 may be controlled by at least one of the heating means and the cooling means (not shown in the figure), or may be left to the natural temperature rise at the time of discharge. When heating the substrate 214, the heater may be installed on the outside or the inside of the substrate 214. When cooling the substrate 214, a cooling gas or liquid may be circulated inside the substrate 214.
When it is desired to avoid an increase in the temperature of the surface of the substrate 214 due to electric discharge, it is effective to adjust the high-energy gas flow that hits the surface of the substrate 214. In this case, conditions such as gas flow rate, discharge output, and pressure are adjusted so as to reach the required temperature.

Further, instead of trimethylgallium gas, an organometallic compound containing aluminum or a hydride such as diborane can 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 film forming chamber 210 via the gas introduction tube 215 and the shower nozzle 216 to form a film containing nitrogen and indium on the substrate 214. Then, this film absorbs the ultraviolet rays generated when the film is continuously formed and deteriorates the single-layer photosensitive layer. Therefore, damage to the single-layer photosensitive layer due to the generation of ultraviolet rays during film formation is suppressed.

As a method for doping the dopant at the time of film formation, SiH ₃ and SnH ₄ for n-type and biscyclopentadienylmagnesium, dimethylcalcium, dimethylstrontium, etc. for p-type are used in a gas state. use. Further, in order to dope the dopant element into the surface layer, a known method such as a heat diffusion method or an ion implantation method may be adopted.
Specifically, for example, by introducing a gas containing at least one dopant element into the film forming chamber 210 via the gas introduction pipe 215 and the shower nozzle 216, a conductive type such as n-type or p-type can be obtained. Obtain an inorganic protective layer.

In the film forming apparatus described with reference to FIGS. 3 and 4, the active nitrogen or active hydrogen formed by the discharge energy may be independently controlled by providing a plurality of active apparatus, or with a nitrogen atom such as _NH3 . A gas containing hydrogen atoms at the same time may be used. Further H ₂ may be added. Further, the condition that active hydrogen is freely generated from the organometallic compound may be used.
By doing so, activated carbon atoms, gallium atoms, nitrogen atoms, hydrogen atoms, etc. are present 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 an organic metal compound as a molecule.
Therefore, 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. 3 and 4 uses a high-frequency oscillator, but is not limited to this, and for example, a microwave oscillator may be used or an electro. A cyclotron resonance method or a helicon plasma type device may be used. Further, in the case of a high frequency oscillator, it may be an inductive type or a capacitive type.
Further, two or more of these devices may be used in combination, or two or more of the same type of devices may be used. A high-frequency oscillator is preferable in order to suppress the temperature rise on the surface of the substrate 214 by irradiation with plasma, but a device for suppressing heat irradiation may be provided.

When two or more different types of plasma generators (plasma generating means) are used, it is preferable to generate discharges at the same pressure at the same time. Further, a pressure difference may be provided between the region where the discharge is performed and the region where the film is formed (the portion where the substrate is installed). These devices may be arranged in series with respect to the gas flow formed in the film forming apparatus from the portion where the gas is introduced to the portion where the gas is discharged, or both devices may be arranged on the film forming surface of the substrate. They may be arranged so as to face each other.

For example, when two types of plasma generating means are installed in series with respect to a gas flow, taking the film forming apparatus shown in FIG. 3 as an example, the shower nozzle 216 is used as an electrode to cause a discharge in the film forming chamber 210. It is used as a plasma generator of 2. In this case, for example, a high frequency voltage is applied to the shower nozzle 216 via the gas introduction pipe 215 to cause a 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 flat plate electrode 219 in the film forming chamber 210, and the cylindrical electrode is used to use the film forming chamber 210. Causes an electric discharge inside.
Further, when two different types of plasma generators are used under the same pressure, for example, when a microwave oscillator and a high frequency oscillator are used, the excitation energy of the excited species can be significantly changed, and the film quality can be controlled. It is valid. Further, the discharge may be performed in the vicinity of atmospheric pressure (70,000 Pa or more and 110,000 Pa or less). When discharging in the vicinity of atmospheric pressure, it is preferable to use He as the carrier gas.

To form the inorganic protective layer, for example, a substrate 214, which is a laminate for manufacturing a photoconductor laminated up to a charge transport layer, is installed in a film forming chamber 210, and a mixed gas having a different composition is introduced to protect the inorganic layer. Form a layer.

Further, as the film forming condition, for example, in the case of discharging by high frequency discharge, the frequency is preferably in the range of 10 kHz or more and 50 MHz or less in order to perform high quality film forming at a low temperature. The output depends on the size of the substrate 214, but is preferably in the range of 0.01 W / cm ² or more and 0.2 W / cm ² or less with respect to the surface area of the substrate. The rotation speed of the substrate 214 is preferably in the range of 0.1 rpm or more and 500 rpm or less.

(Underlay layer)
The undercoat layer is a layer provided between the conductive substrate and the single-layer photosensitive layer.
The undercoat layer is not particularly limited, and for example, a layer containing a binder resin and a charge transport material (for example, the hole transport material described above), a binder resin and inorganic particles (for example, metal oxide particles) can be used. Examples thereof include a layer containing, a layer containing a binder resin and resin particles, a layer formed of a cured film (crosslinked film), a layer containing various particles in the cured film, and the like.

Examples of the binder resin contained in the undercoat layer include acetal resin (for example, polyvinyl butyral), polyvinyl alcohol resin, polyvinyl acetal resin, casein resin, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, and unsaturated. Polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, urea resin, phenol resin, phenol-formaldehyde resin, melamine resin , Known polymer compounds such as urethane resin, alkyd resin, epoxy resin and the like can be mentioned.

Examples of the inorganic particles contained in the undercoat layer include inorganic particles having a powder resistivity (volume resistivity) of ^{102 Ωcm or more and 10 11 Ωcm} or less. As the inorganic particles having this resistance value, for example, metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zinc oxide particles are preferable, and zinc oxide particles are particularly preferable.
The volume average particle size of the inorganic particles is, for example, preferably 50 nm or more and 2000 nm or less (preferably 60 nm or more and 1000 nm or less).

The undercoat layer is preferably formed, for example, by using a coating liquid for forming an undercoat layer, applying it on a conductive substrate by a dip coating method, and drying it.

The membrane elastic modulus of the undercoat layer is preferably 5 GPa or more, and more preferably 10 GPa or more.
Further, as the film thickness of the undercoat layer, for example, a range of 0.1 μm or more and 20 μm or less can be mentioned.

Here, a method for measuring the film elastic modulus of the single-layer type photosensitive layer, the inorganic protective layer, and the undercoat layer will be described.
The film elastic modulus of each layer is obtained from a depth profile obtained by the continuous rigidity method (CSM) (US Pat. No. 4,484,141) using Nano Indicator SA2 manufactured by MTS Systems, and the indentation depth is measured from 100 nm to 300 nm. Use the obtained average value. The following are the measurement conditions.
-Measurement environment: 23 ° C, 55% RH
-Used indenter: Diamond regular triangular pyramid indenter (Berkovic indenter) Triangular pyramid indenter-Test mode: CSM mode The measurement sample is for film formation of the single-layer type photosensitive layer, inorganic protective layer, and undercoat layer to be measured. It may be a sample formed on a substrate under the same conditions as described above.
Further, the measurement sample may be a sample obtained by removing the single-layer type photosensitive layer, the inorganic protective layer, and the undercoat layer from the electrophotographic photosensitive member after preparation.
The film elastic modulus of the single-layer type photosensitive layer, the inorganic protective layer, and the undercoat layer is measured from the electrophotographic photosensitive member after production as follows.
First, the produced photoconductor is cut into 2 cm squares. The film elastic modulus of the inorganic protective layer is measured, and then the inorganic protective layer is scraped with sandpaper or the like. Then, the film elastic modulus of the exposed single-layer type photosensitive layer is measured, and after the measurement, the single-layer type photosensitive layer (and the intermediate layer if necessary) is scraped with sandpaper or the like. Subsequently, the membrane elastic modulus of the exposed undercoat layer is measured.

[Image forming device (and process cartridge)]
The image forming apparatus according to the present embodiment includes an electrophotographic photosensitive member, a charging means for charging the surface of the electrophotographic photosensitive member, and an electrostatic latent image forming on the surface of the charged electrophotographic photosensitive member. Means, a developing means for developing an electrostatic latent image formed on the surface of an electrophotographic photosensitive member with a developer containing toner to form a toner image, and a transfer means for transferring the toner image to the surface of a recording medium. To be equipped with. Then, as the electrophotographic photosensitive member, the electrophotographic photosensitive member according to the present embodiment is applied.

The image forming apparatus according to the present embodiment is an apparatus provided with a fixing means for fixing the toner image transferred to the surface of the recording medium; direct transfer to directly transfer the toner image formed on the surface of the electrophotographic photosensitive member to the recording medium. Device of the method; Intermediate transfer in which the toner image formed on the surface of the electrophotographic photosensitive member is primarily transferred to the surface of the intermediate transfer body, and the toner image transferred to the surface of the intermediate transfer body is secondarily transferred to the surface of the recording medium. Device of the method; A device equipped with a cleaning means for cleaning the surface of the electrophotographic photosensitive member after the transfer of the toner image and before charging; the surface of the electrophotographic photosensitive member is irradiated with xerographic light after the transfer of the toner image and before charging. A device provided with a static elimination means for eliminating static electricity; a well-known image forming apparatus such as a device provided with an electrophotographic photosensitive member heating member for increasing the temperature of the electrophotographic photosensitive member and reducing the relative temperature is applied.

In the case of an intermediate transfer type apparatus, the transfer means is, for example, a primary transfer body in which a toner image is transferred to the surface and a primary transfer of a toner image formed on the surface of an electrophotographic photosensitive member to the surface of the intermediate transfer body. A configuration comprising a transfer means and a secondary transfer means for secondary transfer of the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium is applied.

The image forming apparatus according to the present embodiment may be either a dry developing type image forming apparatus or a wet developing method (development method using a liquid developer) image forming apparatus.

In the image forming apparatus according to the present embodiment, for example, the portion provided with the electrophotographic photosensitive member may have a cartridge structure (process cartridge) attached to and detached from the image forming apparatus. As the process cartridge, for example, a process cartridge including the electrophotographic photosensitive member according to the present embodiment is preferably used. In addition to the electrophotographic photosensitive member, the process cartridge may include at least one selected from the group consisting of, for example, a charging means, an electrostatic latent image forming means, a developing means, and a transfer means.

Hereinafter, an example of the image forming apparatus according to the present embodiment will be shown, but the present invention is not limited thereto. The main parts shown in the figure will be described, and the description thereof will be omitted for the others.

FIG. 5 is a schematic configuration diagram showing an example of an image forming apparatus according to the present embodiment.
As shown in FIG. 5, the image forming apparatus 100 according to the present embodiment includes a process cartridge 300 including an electrophotographic photosensitive member 7, an exposure apparatus 9 (an example of an electrostatic latent image forming means), and a transfer apparatus 40 (primary). A transfer device) and an intermediate transfer body 50 are provided. In the image forming apparatus 100, the exposure apparatus 9 is arranged at a position where the electrophotographic photosensitive member 7 can be exposed to the electrophotographic photosensitive member 7 from the opening of the process cartridge 300, and the transfer apparatus 40 is arranged via the intermediate transfer body 50. The intermediate transfer body 50 is arranged at a position facing the seventh, and a part of the intermediate transfer body 50 is arranged in contact with the electrophotographic photosensitive member 7. Although not shown, it also has a secondary transfer device that transfers the toner image transferred to the intermediate transfer body 50 to a recording medium (for example, paper). The intermediate transfer body 50, the transfer device 40 (primary transfer device), and the secondary transfer device (not shown) correspond to an example of the transfer means. In the image forming apparatus 100, the control device 60 (an example of the control means) is an apparatus for controlling the operation of each apparatus and each member in the image forming apparatus 100, and is arranged so as to be connected to each apparatus and each member. ing.

In the process cartridge 300 in FIG. 5, an electrophotographic photosensitive member 7, a charging device 8 (an example of a charging means), a developing device 11 (an example of a developing means), and a cleaning device 13 (an example of a cleaning means) are integrated in a housing. I support it. The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is arranged so as to come into contact with the surface of the electrophotographic photosensitive member 7. The cleaning member may be a conductive or insulating fibrous member instead of the mode of the cleaning blade 131, and may be used alone or in combination with the cleaning blade 131.

In addition, in FIG. 5, as an image forming apparatus, a fibrous member 132 (roll shape) that supplies a lubricant 14 to the surface of an electrophotographic photosensitive member 7 and a fibrous member 133 (flat brush shape) that assists cleaning are shown. Examples are shown, but these are arranged as needed.

Hereinafter, each configuration of the image forming apparatus according to the present embodiment will be described.

-Charging device-
As the charging device 8, for example, a contact-type charging device using a conductive or semi-conductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube, or the like is used. Further, a non-contact roller charger, a scorotron charger using corona discharge, a corotron charger, or the like, which is known per se, is also used.

-Exposure device-
Examples of the exposure apparatus 9 include an optical system device that exposes light such as a semiconductor laser beam, an LED light, and a liquid crystal shutter light on the surface of the electrophotographic photosensitive member 7 in a predetermined image pattern. The wavelength of the light source is within the spectral sensitivity region of the electrophotographic photosensitive member. The mainstream wavelength of a semiconductor laser is near infrared, which has an oscillation wavelength in the vicinity of 780 nm. However, the wavelength is not limited to this, and a laser having an oscillation wavelength in the 600 nm range or a laser having an oscillation wavelength of 400 nm or more and 450 nm or less may be used as a blue laser. Further, a surface-emitting laser light source of a type capable of outputting a multi-beam is also effective for forming a color image.

-Developer-
Examples of the developing device 11 include a general developing device that develops by contacting or non-contacting a developer. The developing device 11 is not particularly limited as long as it has the above-mentioned functions, and is selected according to the purpose. For example, a known developer having a function of adhering a one-component developer or a two-component developer to the electrophotographic photosensitive member 7 using a brush, a roller, or the like can be mentioned. Of these, those using a developing roller in which the developing agent is held on the surface are preferable.

The developing agent used in the developing apparatus 11 may be a one-component developing agent containing only toner or a two-component developing agent containing a toner and a carrier. Further, the developer may be magnetic or non-magnetic. Well-known developeres are applied.

-Cleaning device-
As the cleaning device 13, a cleaning blade type device including a cleaning blade 131 is used.
In addition to the cleaning blade method, a fur brush cleaning method and a simultaneous development cleaning method may be adopted.

-Transfer device-
As the transfer device 40, for example, a contact type transfer charger using a belt, a roller, a film, a rubber blade, or the like, a scorotron transfer charger using corona discharge, a corotron transfer charger, or the like, which is known per se, can be used. Can be mentioned.

-Intermediate transcript-
As the intermediate transfer body 50, a belt-shaped material (intermediate transfer belt) containing semi-conductive polyimide, polyamide-imide, polycarbonate, polyarylate, polyester, rubber, or the like is used. Further, as the form of the intermediate transfer body, a drum-shaped one may be used in addition to the belt-shaped one.

-Control device-
The control device 60 is configured as a computer that controls the entire device and performs various operations. Specifically, the control device 60 is, for example, a CPU (Central Processing Unit; Central Processing Unit), a ROM (Read Only Memory) that stores various programs, and a RAM (Random Access Memory) that is used as a work area when the programs are executed. ), A non-volatile memory for storing various information, and an input / output interface (I / O). Each of the CPU, ROM, RAM, non-volatile memory, and I / O is connected via a bus. Each part of the image forming apparatus 100 such as the electrophotographic photosensitive member 7 (including the drive motor 30), the charging device 8, the exposure device 9, the developing device 11, and the transfer device 40 is connected to the I / O.

The CPU executes, for example, a control program of a program (for example, an image forming sequence, a recovery sequence, etc.) stored in a ROM or a non-volatile memory, and controls the operation of each part of the image forming apparatus 100. RAM is used as working memory. In the ROM or the non-volatile memory, for example, a program executed by the CPU, data necessary for processing by the CPU, and the like are stored. The control program and various data may be stored in another storage device such as a storage unit, or may be acquired from the outside via the communication unit.

Further, various drives may be connected to the control device 60. As various drives, data can be read from a computer-readable portable recording medium such as a flexible disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, or a USB (Universal Serial Bus) memory, or data can be read from the recording medium. There is a device that writes data. When various drives are provided, the control program may be recorded on a portable recording medium, and the control program may be read and executed by the corresponding drive.

FIG. 6 is a schematic configuration diagram showing another example of the image forming apparatus according to the present embodiment.
The image forming apparatus 120 shown in FIG. 6 is a tandem type multicolor image forming apparatus equipped with four process cartridges 300. In the image forming apparatus 120, four process cartridges 300 are arranged in parallel on the intermediate transfer body 50, and one electrophotographic photosensitive member is used for each color. The image forming apparatus 120 has the same configuration as the image forming apparatus 100 except that it is a tandem type.

The image forming apparatus 100 according to the present embodiment is not limited to the above configuration, and is, for example, a cleaning apparatus around the electrophotographic photosensitive member 7 on the downstream side in the rotation direction of the electrophotographic photosensitive member 7 with respect to the transfer device 40. A first static eliminator for aligning the polarities of the remaining toner and facilitating removal with a cleaning brush may be provided on the upstream side of the electrophotographic photosensitive member in the rotation direction rather than the cleaning device 13. Also, a second static eliminator for eliminating static electricity on the surface of the electrophotographic photosensitive member 7 may be provided on the downstream side in the rotation direction of the electrophotographic photosensitive member and on the upstream side in the rotation direction of the electrophotographic photosensitive member than the charging device 8. ..

Further, the image forming apparatus 100 according to the present embodiment is not limited to the above configuration, and is a well-known configuration, for example, a direct transfer type image forming apparatus that directly transfers a toner image formed on the electrophotographic photosensitive member 7 to a recording medium. It may be adopted.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the following examples, "parts" means parts by mass.

[Preparation of silica particles]
-Silica particles (1)-
Untreated (hydrophilic) silica particles "trade name: OX50 (manufactured by Aerosil)" in 100 parts by mass as a hydrophobizing agent 1,1,1,3,3,3-hexamethyldisilazane (Tokyo Chemical Industry Co., Ltd.) (Manufactured by) 30 parts by mass was added and reacted for 24 hours, and then the silica particles (1) were collected by filtration to obtain hydrophobized silica particles (1).
The silica particles (1) had a condensation rate of 93% and had a trimethylsilyl group on the surface. The volume average particle size of the silica particles (1) was 40 nm.

<Example 1>
-Formation of a single-layer photosensitive layer-
The Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using CuKα characteristic X-ray as the charge generation material is at least at the positions of 7.3 °, 16.0 °, 24.9 °, and 28.0 °. V-type hydroxygallium phthalocyanine pigment having a diffraction peak: 2 parts by mass (amount of 2 parts by mass with respect to the single-layer type photosensitive layer) and an exemplary compound (2) of an electron transport material represented by the general formula (2). -2): 8 parts by mass, a hole transport material represented by the structural formula (HT-D): 14 parts by mass, and an exemplary compound (1-1) of the hole transport material represented by the general formula (1). ): 22 parts by mass, bisphenol Z polycarbonate resin as a binder resin (viscosity average molecular weight: 45,000): 54 parts by mass, silica particles (1): 100 parts by mass, and 400 parts by mass of tetrahydrofuran as a solvent. Was mixed and dispersed with a sand mill using glass beads having a diameter of 1 mmφ for 4 hours to obtain a coating liquid for forming a photosensitive layer.

An aluminum substrate (tube with a diameter of 30 mm, a length of 244.5 mm, and a wall thickness of 0.7 mm) was prepared. This aluminum substrate was immersed in a water tank containing water having a pH of 8.1 to wash the aluminum substrate. After the aluminum substrate taken out of the water tank was dried, the coating liquid for forming a photosensitive layer was immersed and coated on the aluminum substrate and dried at 125 ° C. for 24 minutes to form a single-layer photosensitive layer having a film thickness of 25 μm. ..

Through the above steps, an organic photoconductor (1) having only a single-layer type photosensitive layer formed on an aluminum substrate 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 organic photoconductor (1). The formation of this inorganic protective layer was performed using a film forming apparatus having the structure shown in FIG.

First, the organic photoconductor (1) was 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 was evacuated through the exhaust port 211 until the pressure became 0.1 Pa.
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 section 221 provided with the flat plate electrode 219 having a diameter of 85 mm. A 13.56 MHz radio wave was set to an output of 150 W by a high frequency power supply unit 218 and a matching circuit (not shown in FIG. 5), matched with a tuner, and discharged from a flat 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 into the plasma diffusion section 217 in the film forming chamber 210 via the gas introduction pipe 215. At this time, the reaction pressure in the film forming chamber 210 measured by the Baratron vacuum gauge was 5.3 Pa.
In this state, the organic photoconductor (1) was formed into a film for 25 hours while rotating at a speed of 500 rpm, and an inorganic protective layer having a film thickness of 5 μm was formed on the surface of the charge transport layer of the organic photoconductor (1).
The surface roughness Ra on the outer peripheral surface of the inorganic protective layer was 1.9 nm.
The elemental composition ratio (oxygen / gallium) of oxygen and gallium in the inorganic protective layer was 1.25.

Through the above steps, the electrophotographic photosensitive member of Example 1 in which the single-layer type photosensitive layer and the inorganic protective layer were sequentially formed on the conductive substrate was obtained.

<Example 2>
An electrophotographic photosensitive member of Example 2 was obtained in the same manner as in Example 1 except that the film forming time in the film forming apparatus was changed to 20 hours to form an inorganic protective layer having a film thickness of 4 μm.

<Example 3>
An electrophotographic photosensitive member of Example 3 was obtained in the same manner as in Example 1 except that the film forming time in the film forming apparatus was changed to 15 hours to form an inorganic protective layer having a film thickness of 3 μm.

<Example 4>
An electrophotographic photosensitive member of Example 4 was obtained in the same manner as in Example 1 except that the film forming time in the film forming apparatus was changed to 5 hours to form an inorganic protective layer having a film thickness of 1 μm.

<Example 5>
In the formation of the single-layer type photosensitive layer in Example 1, the film thickness of the single-layer type photosensitive layer was set to 10 μm to obtain an organic photosensitive member (2).
Subsequently, in the same manner as in Example 1 except that the organic photoconductor (2) was used and the film forming time in the film forming apparatus was changed to 15 hours to form an inorganic protective layer having a film thickness of 3 μm. An electrophotographic photosensitive member of 5 was obtained.

<Example 6>
In the formation of the single-layer type photosensitive layer in Example 1, a coating solution for forming a photosensitive layer which did not contain silica particles (1) and was obtained by changing to 250 parts by mass of tetrahydrofuran was used, and the film thickness was 10 μm. A single-layer photosensitive layer was formed to obtain an organic photosensitive member (3).
Subsequently, in the same manner as in Example 1 except that the organic photoconductor (3) was used and the film forming time in the film forming apparatus was changed to 15 hours to form an inorganic protective layer having a film thickness of 3 μm. 6 electrophotographic photosensitive members were obtained.

<Example 7>
-Formation of the undercoat layer-
Zinc oxide: (Average particle diameter 70 nm: manufactured by Teika Co., Ltd .: specific surface area value 15 m2 / g) 100 parts by mass is stirred and mixed with 500 parts by mass of tetrahydrofuran, and a silane coupling agent (KBM503: manufactured by Shin-Etsu Chemical Co., Ltd.) 1.3 mass. The portion was added and stirred for 2 hours. Then, tetrahydrofuran was distilled off under reduced pressure and baked at 120 ° C. for 3 hours to obtain zinc oxide surface-treated with a silane coupling agent.
110 parts by mass of the obtained surface-treated zinc oxide (silane coupling agent surface-treated zinc oxide) was stirred and mixed with 500 parts by mass of tetrahydrofuran, and 0.6 part by mass of alizarin was dissolved in 50 parts by mass of tetrahydrofuran. The solution was added and stirred at 50 ° C. for 5 hours. Then, zinc oxide to which alizarin was added was filtered off by vacuum filtration, and further dried under reduced pressure at 60 ° C. to obtain zinc oxide to which alizarin was added.
60 parts by mass of this zinc oxide imparted with alizarin, 13.5 parts by mass of a curing agent (blocked isocyanate Sumijoule 3175, manufactured by Sumitomo Bavarian Urethane Co., Ltd.), and 15 parts by mass of butyral resin (Eslek BM-1, manufactured by Sekisui Chemical Co., Ltd.). And 85 parts by mass of methyl ethyl ketone were mixed to obtain a mixed solution. 38 parts by mass of this mixed solution and 25 parts by mass of methyl ethyl ketone were mixed and dispersed with a sand mill using 1 mmφ glass beads for 2 hours to obtain a dispersion solution.
To the obtained dispersion, dioctyltin dilaurate: 0.005 part by mass and silicone resin particles (Tospearl 145, manufactured by Momentive Performance Materials): 40 parts by mass were added as catalysts to form an undercoat layer. A coating solution for use was obtained.
This coating liquid for forming an undercoat layer was applied onto an aluminum substrate by a dip coating method and dried and cured at 170 ° C. for 40 minutes to form an undercoat layer having a film thickness of 15 μm.

-Formation of single-layer photosensitive layer and inorganic protective layer-
A single-layer type photosensitive layer was formed on the obtained undercoat layer in the same manner as in Example 1 except that the film thickness was set to 10 μm, and an organic photosensitive member (4) was obtained.
Subsequently, an example was carried out in the same manner as in Example 1 except that the organic photoconductor (4) was used and the film forming time in the film forming apparatus was changed to 20 hours to form an inorganic protective layer having a film thickness of 4 μm. 7 electrophotographic photosensitive members were obtained.

<Comparative Example 1>
In the formation of the single-layer type photosensitive layer in Example 1, the film thickness of the single-layer type photosensitive layer was set to 28 μm to obtain an organic photosensitive member (5).
Subsequently, in the same manner as in Example 1, Comparative Example except that the organic photoconductor (5) was used and the film forming time in the film forming apparatus was changed to 15 hours to form an inorganic protective layer having a film thickness of 3 μm. 1 electrophotographic photosensitive member was obtained.

(Measurement and evaluation)
-Measurement of membrane elastic modulus and film thickness-
The film elastic modulus of the undercoat layer, the single-layer type photosensitive layer, and the inorganic protective layer in the electrophotographic photosensitive member obtained in each example was measured by the method described above.
Further, the film thicknesses of the undercoat layer, the single-layer type photosensitive layer, and the inorganic protective layer in the electrophotographic photosensitive member obtained in each example were also measured by the method described above, and between the conductive substrate and the inorganic protective layer. The total film thickness of the layers intervening in was calculated. The results are shown in Table 1.

-Evaluation of dents-
The electrophotographic photosensitive member obtained in each example was incorporated into an image forming apparatus (DocuCenter-V C7775 manufactured by Fuji Xerox Co., Ltd.) and evaluated as follows.
Under an environment of temperature 20 ° C. and humidity 40% RH, after continuously outputting 10,000 sheets of full-scale halftone images with an image density of 30% on A4 paper, the surface of the electrophotographic photosensitive member (that is, the surface of the inorganic protective layer) is measured with an optical microscope. (Made by Keyence, model number: VHX-100) measures 10 fields at a magnification of 450 times, counts the number of dents (dents), and counts the number of dents per unit area (1 mm x 1 mm) (hereinafter referred to as "dents"). Also called "number") was calculated.
The evaluation criteria are as follows. The results are shown in Table 1.

-Evaluation criteria-
A: The number of dents is 5 or less B: The number of dents is more than 5 and 10 or less C: The number of dents is more than 10 and 15 or less D: The number of dents is more than 15 and 20 or less E: The number of dents exceeds 20

From the above results, it can be seen that the occurrence of dents is suppressed in this example as compared with the comparative example.

1 Conductive substrate, 2 Undercoat layer, 3 Single layer type photosensitive layer, 4 Inorganic protective layer, 7A, 7B, 7 Electrophotographic photosensitive member (photoreceptor), 8 Charging device, 9 Exposure device, 11 Developing device, 13 Cleaning Equipment, 14 Lubricating material, 30 Drive motor, 40 Transfer device, 50 Intermediate transfer body, 60 Control device, 100 Image forming device, 120 Image forming device, 131 Cleaning blade, 132 Fibrous member (roll), 133 Fibrous member (Flat brush shape), 300 process cartridge, 210 film forming chamber, 211 exhaust port, 212 substrate rotating part, 213 substrate support member, 214 substrate, 215, 220 gas introduction tube, 216 shower nozzle, 217 plasma diffuser, 218 high frequency Power supply unit, 219 flat plate electrode, 221 high frequency discharge tube unit, 222 high frequency coil, 223 quartz tube

Claims (7)

With a conductive substrate,
A single-layer organic photosensitive layer provided on the conductive substrate, an inorganic protective layer provided on the single-layer organic photosensitive layer, and the like.
Have,
The total film thickness of the layer interposed between the conductive substrate and the inorganic protective layer is 10 μm or more and 25 μm or less.
The ratio (A / B) of the film thickness A of the inorganic protective layer to the total film thickness B of the layer interposed between the conductive substrate and the inorganic protective layer is 0.12 or more.
An electrophotographic photosensitive member having a film elastic modulus of 5 GPa or more in the single-layer organic photosensitive layer . The electrophotographic photosensitive member according to claim 1, wherein the single-layer organic photosensitive layer contains a binder resin, a charge generating material, a hole transporting material, an electron transporting material, and silica particles. The electrophotographic photosensitive member according to claim 2, wherein the content of the silica particles with respect to the single-layer organic photosensitive layer is 40% by mass or more and 70% by mass or less. The electrophotographic photosensitive member according to any one of claims 1 to 3 , wherein the inorganic protective layer is an inorganic protective layer composed of a metal oxide layer containing a Group 13 element and oxygen. The electrophotographic photosensitive member according to claim 4 , wherein the metal oxide layer is a metal oxide layer containing gallium oxide. The electrophotographic photosensitive member according to any one of claims 1 to 5 is provided.
A process cartridge that can be attached to and detached from the image forming device. The electrophotographic photosensitive member according to any one of claims 1 to 5 .
A charging means for charging the surface of the electrophotographic photosensitive member and
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive member,
A developing means for developing an electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image, and a developing means.
A transfer means for transferring the toner image to the surface of a recording medium,
An image forming apparatus.

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