JP2024044123A - Electrophotographic photoreceptor, process cartridge and image forming apparatus - Google Patents

Abstract

[Problem] To provide an electrophotographic photoreceptor in which peeling of an inorganic protective layer from the surface of a photosensitive layer on the interface side with the inorganic protective layer is suppressed. [Solution] An electrophotographic photoreceptor having a conductive substrate, a photosensitive layer provided on the conductive substrate, and an inorganic protective layer provided on the photosensitive layer, the photosensitive layer having a water contact angle of 82° or more on the surface on the interface side with the inorganic protective layer, and the content of silica particles relative to the total solid content of the photosensitive layer is 0% by mass or 20% by mass or less. [Selected Figure] Figure 1

Description

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

Patent Document 1 states, ``A photosensitive layer and a surface layer are laminated in this order on a conductive substrate, and among the elements constituting the surface layer, the total amount of Group 13 elements, oxygen, and hydrogen. The sum of the respective composition ratios of the oxygen and the Group 13 element is 0.95 or more, and the elemental composition ratio of the oxygen and the Group 13 element (oxygen/Group 13 element) is 1.1 or more and 1.5 or less. "An electrophotographic photoreceptor" is disclosed.

Patent document 2 discloses an electrophotographic photoreceptor in which an organic photosensitive layer and an inorganic surface protective layer are laminated in this order on a conductive substrate, and at least the outermost surface portion of the organic photosensitive layer that contacts the surface protective layer contains a specific dioxotetracenedione derivative.

JP 2008-268266 A Japanese Patent Application Publication No. 2002-116564

Conventionally, when using an electrophotographic photoreceptor in which an inorganic protective layer is provided on a photosensitive layer, the inorganic protective layer sometimes peels off from the surface of the photosensitive layer on the interface side with the inorganic protective layer.
Therefore, in the present disclosure, the photosensitive layer "contains lubricating oil in an amount of 0% by mass or less than 0.0001% by mass based on the total solid content of the photosensitive layer" or "the surface on the interface side with the inorganic protective layer". To provide an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed compared to the case where the water contact angle is less than 82°. Take it as a challenge.

Specific means for solving the above problems include the following aspects:

<1> A conductive substrate,
a photosensitive layer provided on the conductive substrate;
an inorganic protective layer provided on the photosensitive layer;
has
The photosensitive layer has a water contact angle of 82° or more on the surface on the interface side with the inorganic protective layer, and the content of silica particles is 0% by mass or 20% by mass or less based on the total solid content of the photosensitive layer. An electrophotographic photoreceptor.
<2> The electrophotographic photoreceptor according to <1>, wherein the photosensitive layer contains lubricating oil in an amount of 0.0001% by mass or more based on the total solid content of the photosensitive layer.
<3> The electrophotographic photoreceptor according to <1>, wherein the lubricating oil includes at least one of silicone oil and fluorine-containing oil.
<4> The electrophotographic photoreceptor according to <3>, wherein the lubricating oil includes the silicone oil.
<5> The electrophotographic photoreceptor according to <1>, wherein the inorganic protective layer is an inorganic protective layer containing oxygen, hydrogen, and a Group 13 element.
<6> The electrophotographic photosensitive layer according to <5>, wherein the inorganic protective layer has an elemental composition ratio of the oxygen and the Group 13 element (oxygen/Group 13 element) of 1.1 or more and 1.5 or less. body.
<7> A conductive substrate,
a photosensitive layer provided on the conductive substrate;
an inorganic protective layer provided on the photosensitive layer;
has
The photosensitive layer contains lubricating oil at 0.0001% by mass or more based on the total solid content of the photosensitive layer, and the content of silica particles is 0% by mass or 20% by mass based on the total solid content of the photosensitive layer. An electrophotographic photoreceptor as follows.
<8> An electrophotographic photoreceptor according to any one of <1> to <7> above,
A process cartridge that can be attached to and removed from an image forming apparatus.
<9> The electrophotographic photoreceptor according to any one of <1> to <7> above,
Charging means for charging the surface of the electrophotographic photoreceptor;
an electrostatic latent image forming means for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;
a developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor to form a toner image with a developer containing toner;
a transfer means for transferring the toner image onto the surface of a recording medium;
An image forming apparatus comprising:

According to the invention related to <1> or <5>, there is provided an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed, as compared to when the water contact angle of the surface of the photosensitive layer on the interface side with the inorganic protective layer is less than 82°.
According to the invention related to <2>, there is provided an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed, compared to when the photosensitive layer contains less than 0.0001 mass % of a lubricating oil relative to the total solid content of the photosensitive layer.
According to the invention relating to <3> or <4>, there is provided an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed, compared to when the lubricating oil is a polyalphaolefin-based lubricating oil, which is a type of hydrocarbon-based synthetic oil.
According to the invention related to <6>, there is provided an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed, as compared with a case in which the elemental composition ratio of oxygen and Group 13 element (oxygen/Group 13 element) in the inorganic protective layer is less than 1.1 or exceeds 1.5.

According to the invention according to <7>, the inorganic protective layer and Provided is an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side is suppressed.
According to the invention according to <8> or <9>, the photosensitive layer "contains lubricating oil in an amount of 0% by mass or less than 0.0001% by mass based on the total solid content of the photosensitive layer" or "the Peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed compared to the case where the water contact angle on the surface on the interface side with the inorganic protective layer is less than 82°. A process cartridge and an image forming apparatus including an electrophotographic photoreceptor are provided.

FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of the electrophotographic photoreceptor of the present embodiment. FIG. 2 is a schematic diagram illustrating an example of a film forming apparatus used for forming an inorganic protective layer of the electrophotographic photoreceptor according to the present embodiment. 1 is a schematic diagram showing an example of a plasma generation device used for forming an inorganic protective layer of an electrophotographic photoreceptor according to an embodiment of the present invention. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. FIG. 4 is a schematic configuration diagram illustrating another example of an image forming apparatus according to the present embodiment.

Embodiments of the present invention will be described below. These descriptions and examples are illustrative of the embodiments and do not limit the scope of the embodiments.

In the numerical ranges described step by step in this specification, the upper limit value or lower limit value described in one numerical range may be replaced with the upper limit value or lower limit value of another numerical range described step by step. good. Furthermore, in the numerical ranges described in this disclosure, the upper limit or lower limit of the numerical range may be replaced with the values shown in the Examples.

In this specification, each component may contain multiple corresponding substances.
In this specification, when referring to the amount of each component in a composition, if multiple substances corresponding to each component are present in the composition, the amount refers to the total amount of those multiple substances present in the composition, unless otherwise specified.

<Electrophotographic photoreceptor>
The electrophotographic photoreceptor according to the first embodiment includes: a conductive base, a subbing layer provided on the conductive base, a photosensitive layer provided on the subbing layer, and the photosensitive layer. an inorganic protective layer provided thereon, wherein the photosensitive layer has a water contact angle of 82° or more at the surface on the interface side with the inorganic protective layer, and the total solid content of the photosensitive layer is 82° or more. The content of silica particles is 0% by mass or 20% by mass or less.

The electrophotographic photoreceptor according to the second embodiment has a conductive substrate, an undercoat layer provided on the conductive substrate, a charge generating layer provided on the undercoat layer, a photosensitive layer provided on the undercoat layer, and an inorganic protective layer provided on the photosensitive layer, and the photosensitive layer contains a lubricant in an amount of 0.0001% by mass or more relative to the total solid content of the photosensitive layer, and the content of silica particles relative to the total solid content of the photosensitive layer is 0% by mass or 20% by mass or less.

In this specification, matters common to the first and second embodiments will be collectively referred to as "this embodiment."

In conventional electrophotographic photoreceptors having an inorganic protective layer, the inorganic protective layer would peel off from the surface of the photosensitive layer on the interface side with the inorganic protective layer. This is thought to be due to the fact that, for example, areas of low wettability of the photosensitive layer are generated at the interface between the photosensitive layer and the inorganic protective layer, and peeling occurs from these areas of low wettability. This is particularly noticeable when the content of silica particles in the photosensitive layer is 20% by mass or less.

On the other hand, since the electrophotographic photoreceptor according to the present embodiment has the above structure, peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed. This factor is not necessarily clear, or it is speculated as follows.

In the electrophotographic photoreceptor according to the first embodiment, the water contact angle of the photosensitive layer on the surface on the interface side with the inorganic protective layer is 82° or more, especially among the above configurations. That is, the surface of the photosensitive layer that comes into contact with the inorganic protective layer has high wettability with respect to the inorganic protective layer. Therefore, it is considered that the adhesiveness between the photosensitive layer and the inorganic protective layer is high, and peeling of the inorganic protective layer is suppressed.

In the electrophotographic photoreceptor according to the second embodiment, in particular, the photosensitive layer contains lubricating oil in an amount of 0.0001% by mass or more based on the total solid content of the photosensitive layer. Therefore, hydrophobicity is imparted to the surface of the photosensitive layer. As a result, it is thought that the adhesiveness between the photosensitive layer and the inorganic protective layer is high, and peeling of the inorganic protective layer is suppressed.

Hereinafter, an example of the electrophotographic photoreceptor according to the present embodiment will be described in detail with reference to the drawings. In addition, in the drawings, the same or corresponding parts are given the same reference numerals, and overlapping explanations will be omitted.
FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of the electrophotographic photoreceptor according to the present embodiment. The photoreceptor 107A has a structure in which an undercoat layer 101 is provided on a conductive substrate 104, and a charge generation layer 102, a charge transport layer 103, and an inorganic protective layer 106 are sequentially formed thereon.
In FIG. 1, the photoreceptor 107A has a laminated photosensitive layer 105 whose functions are separated into a charge generation layer 102 and a charge transport layer 103, but the photosensitive layer 105 may be a single layer photosensitive layer. good.
Although not shown, an intermediate layer may be further provided between the conductive substrate 104 and the undercoat layer 101 or between the undercoat layer 101 and the photosensitive layer 105.

Each element constituting the electrophotographic photoreceptor will be explained below. Note that the description may be made with reference numerals omitted.

[Photosensitive Layer]
The characteristics of the photosensitive layer common to the multi-layer type photosensitive layer and the single-layer type photosensitive layer will be described below.

In the photosensitive layer according to the present embodiment, the content of silica particles relative to the total solid content of the photosensitive layer is 0% by mass or less than 20% by mass, and preferably 0% by mass or less than 15% by mass.
According to this embodiment, even if the content of silica particles in the photosensitive layer is below the above range, the adhesiveness between the photosensitive layer and the inorganic protective layer is easily maintained at a high level, and peeling of the inorganic protective layer is suppressed.

In the photosensitive layer according to the present embodiment, the content of inorganic particles relative to the total solid content of the photosensitive layer is 0% by mass or less than 20% by mass, and preferably 0% by mass or less than 15% by mass.
According to this embodiment, even if the content of inorganic particles in the photosensitive layer is within the above range, the adhesiveness between the photosensitive layer and the inorganic protective layer is easily maintained at a high level, and peeling of the inorganic protective layer is suppressed.

In the first embodiment, the photosensitive layer has a water contact angle on the surface at the interface with the inorganic protective layer of 82° or more, preferably 84° or more, and more preferably 84° or more and 100° or less.
In the second embodiment, the photosensitive layer preferably has a water contact angle of 82° or more on the surface at the interface with the inorganic protective layer, more preferably 84° or more, and even more preferably 84° or more and 100° or less.

When the water contact angle is within the above range, the surface of the photosensitive layer that comes into contact with the inorganic protective layer tends to have high wettability with the raw material gas for forming the inorganic protective layer during the formation of the inorganic protective layer. Therefore, the adhesiveness between the photosensitive layer and the inorganic protective layer is high, and peeling of the inorganic protective layer is further suppressed.

The water contact angle is an index showing water repellency, and is measured as follows.
In an environment of 25°C temperature and 50% humidity, 3 μL of pure water is dropped onto the surface of the measurement object using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., model number: CA-X-FACE), and the droplet is photographed 3 seconds after dropping using an optical microscope. Then, the water contact angle θ is calculated from the photograph obtained based on the θ/2 method.

There are no particular limitations on the method for adjusting the water contact angle to within the above range, but an example is a method in which a lubricating oil is added to the photosensitive layer.

In the first embodiment, the photosensitive layer preferably contains lubricating oil.
In a second embodiment, the photosensitive layer contains lubricating oil.
When the photosensitive layer contains lubricating oil, the wettability of the surface of the photosensitive layer that comes into contact with the inorganic protective layer tends to be high. Therefore, the adhesiveness between the photosensitive layer and the inorganic protective layer is high, and peeling of the inorganic protective layer is further suppressed.

The type of lubricant is not particularly limited, but for example,
Examples of lubricating oils include silicone oil, fluorine-containing oil, hydrocarbon oil (such as polyalphaolefin), mineral oil, vegetable oil, polyalkylene glycol, alkylene glycol ether, alkanediol, molten wax, and surfactant. Can be mentioned.
The fluorine-containing oil refers to a resin containing at least a fluorine atom in its molecular structure.
Hydrocarbon oil refers to a compound that contains hydrocarbons as a main component and is oily at room temperature (23°C).

The lubricating oil preferably contains at least one of a silicone oil and a fluorine-containing oil, and more preferably contains a silicone oil.
When lubricating oil contains at least one of silicone oil and fluorine-containing oil (more preferably contains silicone oil), the water contact angle value of the surface of the photosensitive layer that contacts with the inorganic protective layer is easily adjusted to the above-mentioned range, and thus wettability is easily improved.Therefore, the adhesion between the photosensitive layer and the inorganic protective layer is high, and the peeling of the inorganic protective layer is more suppressed.

Examples of silicone oil include:
Straight silicone oils such as dimethyl polysiloxane, dimethyl silicone oil, cyclic dimethyl silicone oil, methylphenyl silicone oil, diphenyl silicone oil;
Carpinol-modified silicone oil, phenyl-modified silicone oil, aralkyl-modified silicone oil, alkyl-modified silicone oil, fluoro-modified silicone oil, fluoroalkyl-modified silicone oil, polyol-modified silicone oil, polyester-modified silicone oil, fatty acid ester-modified silicone oil, polyether-modified silicone oil Modified silicone oils such as silicone oil, acrylic-modified silicone oil, hydrogen-modified silicone oil (for example, methylhydrogen-modified silicone oil), and the like can be mentioned.

Fluorine-based oils include perfluoropolyether, chlorotrifluoroethylene, polytetrafluoroethylene, fluorine-containing acrylic polymers, etc.

In the first embodiment, the photosensitive layer preferably contains lubricating oil in an amount of 0.0001% by mass or more based on the total solid content of the photosensitive layer, more preferably 0.0002% by mass or more and 1% by mass or less. Preferably, the content is preferably 0.0002% by mass or more and 0.1% by mass or less.
In the second embodiment, the photosensitive layer contains lubricating oil in an amount of 0.0001% by mass or more based on the total solid content of the photosensitive layer, preferably 0.0002% by mass or more and 1% by mass or less, and preferably 0.0002% by mass or more and 1% by mass or less, based on the total solid content of the photosensitive layer. More preferably, the content is 0.002% by mass or more and 0.1% by mass or less.

When the lubricating oil content is 0.0001% by mass or more, the wettability of the surface of the photosensitive layer that comes into contact with the inorganic protective layer tends to be high. Therefore, the adhesiveness between the photosensitive layer and the inorganic protective layer is high, and peeling of the inorganic protective layer is further suppressed.
When the lubricating oil content is 1% by mass or less based on the total solid content of the photosensitive layer, deterioration of the electrical properties of the photosensitive layer is suppressed.

The laminated photosensitive layer in which the functions are separated into a charge generation layer and a charge transport layer will be explained in detail for each layer below. When the photosensitive layer is a laminated photosensitive layer, the lubricating oil is preferably included in the charge transport layer from the viewpoint of adjusting the water contact angle on the surface on the interface side with the inorganic protective layer.

(Charge Generation Layer)
The charge generating layer is, for example, a layer containing a charge generating material and a binder resin.
The charge generating layer may also be a vapor deposition layer of a charge generating material. The vapor deposition layer of a charge generating material is suitable for use with a non-coherent light source such as an LED (Light Emitting Diode) or an organic EL (Electro-Luminescence) image array. The charge transport layer may further contain a lubricant as necessary. Details of the lubricant are as described above.

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

Among these, it is preferable to use a metal phthalocyanine pigment or a metal-free phthalocyanine pigment as the charge-generating material in order to make it compatible with laser exposure in the near-infrared region. Specifically, for example, hydroxygallium phthalocyanine; chlorogallium phthalocyanine; dichlorotin phthalocyanine; and titanyl phthalocyanine are more preferable.

On the other hand, in order to be compatible with laser exposure in the near-ultraviolet region, charge-generating materials include condensed aromatic pigments such as dibromoanthanthrone; thioindigo pigments; porphyrazine compounds; zinc oxide; trigonal selenium; and bisazo pigments. etc. are preferred.

The above charge generating materials may be used when using incoherent light sources such as LEDs and organic EL image arrays that emit light at a central wavelength between 450 nm and 780 nm. However, from the viewpoint of resolution, when using a thin photosensitive layer of 20 μm or less, the electric field strength in the photosensitive layer becomes high, and a decrease in charge due to charge injection from the substrate, so-called black spots, are likely to occur as image defects. This is particularly noticeable when using charge generating materials that are p-type semiconductors such as trigonal selenium and phthalocyanine pigments and are prone to generating dark current.

In contrast, when an n-type semiconductor such as a fused aromatic pigment, a perylene pigment, or an azo pigment is used as the charge generating material, dark current is unlikely to occur, and image defects called black spots can be suppressed even when the material is made into a thin film.
The n-type is determined by the polarity of the photocurrent that flows using the commonly used time-of-flight method, and those that easily pass electrons as carriers rather than holes are determined to be n-type.

The binder resin used in the charge generating layer may be selected from a wide range of insulating resins, and may also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, polysilane, and the like.
Examples of binder resins include polyvinyl butyral resins, polyarylate resins (polycondensates of bisphenols and aromatic dicarboxylic acids, etc.), polycarbonate resins, polyester resins, phenoxy resins, vinyl chloride-vinyl acetate copolymers, polyamide resins, acrylic resins, polyacrylamide resins, polyvinylpyridine resins, cellulose resins, urethane resins, epoxy resins, casein, polyvinyl alcohol resins, polyvinylpyrrolidone resins, etc. Here, "insulating" means that the volume resistivity is 10 ¹³ Ωcm or more.
These binder resins may be used alone or in combination of two or more.

It is preferable that the mixing ratio of the charge generating material to the binder resin is within the range of 10:1 to 1:10 by mass.

The charge generation layer may also contain other well-known additives.

There are no particular restrictions on the formation of the charge generation layer, and well-known formation methods may be used. and heat as necessary. Note that the charge generation layer may be formed by vapor deposition of a charge generation material. Formation of the charge generation layer by vapor deposition is particularly suitable when a condensed aromatic pigment or perylene pigment is used as the charge generation material.

Examples of the solvent for preparing the coating solution for forming the charge generation layer include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, and n-acetic acid. -butyl, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, toluene and the like. These solvents may be used alone or in combination of two or more.

Examples of methods for dispersing particles (for example, charge generating material) in the coating liquid for forming a charge generating layer include media dispersing machines such as ball mills, vibrating ball mills, attritors, sand mills, and horizontal sand mills, stirring machines, and ultrasonic dispersing machines. Medialess dispersion machines such as , roll mills, and high-pressure homogenizers are used. Examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision under high pressure, and a penetration method in which the dispersion is dispersed by penetrating fine channels under high pressure.
In addition, during this dispersion, it is effective to keep the average particle size of the charge generating material in the coating liquid for forming a charge generating layer to 0.5 μm or less, preferably 0.3 μm or less, and more preferably 0.15 μm or less. .

Methods for applying the coating liquid for forming the charge generating layer onto the undercoat layer (or onto the intermediate layer) include, for example, conventional methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

The thickness of the charge generating layer is preferably set within the range of, for example, 0.1 μm to 5.0 μm, and more preferably 0.2 μm to 2.0 μm.

(Charge Transport Layer)
The charge transport layer is, for example, a layer containing a lubricant, a charge transport material, and a binder resin. The charge transport layer may be a layer containing a lubricant and a polymer charge transport material. Details of the lubricant are as described above.

As charge transport materials, quinone compounds such as p-benzoquinone, chloranil, bromanil, and anthraquinone; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone; xanthone compounds; benzophenone compounds Examples include electron transporting compounds such as cyanovinyl compounds; ethylene compounds. Examples of the charge transporting material include hole transporting compounds such as triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, and hydrazone compounds. These charge transport materials may be used alone or in combination of two or more, but are not limited thereto.

As the charge transport material, from the viewpoint of charge mobility, a triarylamine derivative represented by the following structural formula (a-1) and a benzidine derivative represented by the following structural formula (a-2) are preferable.

In structural formula (a-1), Ar ^T1 , Ar ^T2 , and Ar ^T3 each independently represent a substituted or unsubstituted aryl group, -C ₆ H ₄ -C(R ^T4 )=C(R ^T5 )(R ^T6 ), or -C ₆ H ₄ -CH=CH-CH=C(R ^T7 )(R ^T8 ). R ^T4 , R ^T5 , R ^T6 , R ^T7 , and R ^T8 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.
Examples of the substituent on each of the above groups include a halogen atom, an alkyl group having from 1 to 5 carbon atoms, and an alkoxy group having from 1 to 5 carbon atoms. Examples of the substituent on each of the above groups also include a substituted amino group substituted with an alkyl group having from 1 to 3 carbon atoms.

In structural formula (a-2), R ^T91 and R ^T92 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. ^RT101 , ^RT102 , ^RT111 and ^RT112 are each independently substituted with a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 1 to 2 carbon atoms represents an amino group, a substituted or unsubstituted aryl group, -C(R ^T12 )=C(R ^T13 )(R ^T14 ), or -CH=CH-CH=C(R ^T15 )(R ^T16 ), R ^T12 , R ^T13 , R ^T14 , R ^T15 and R ^T16 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Tm1, Tm2, Tn1 and Tn2 each independently represent an integer of 0 or more and 2 or less.
Examples of substituents for each of the above groups include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. Furthermore, examples of the substituents for each of the above groups include a substituted amino group substituted with an alkyl group having 1 or more and 3 or less carbon atoms.

Here, among the triarylamine derivative represented by the structural formula (a-1) and the benzidine derivative represented by the structural formula (a-2), in particular, "-C ₆ H ₄ -CH=CH-CH= Triarylamine derivatives having "C(R ^T7 )(R ^T8 )" and benzidine derivatives having "-CH=CH-CH=C(R ^T15 )(R ^T16 )" are preferred from the viewpoint of charge mobility.

As the polymeric charge transporting material, known materials having charge transporting properties such as poly-N-vinylcarbazole and polysilane are used. In particular, polyester-based polymeric charge transport materials are particularly preferred. Note that the polymer charge transport material may be used alone, or may be used in combination with a binder resin.

Examples of the binder resin used in the charge transport layer 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, 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-vinylcarbazole, polysilane, etc. Among these, polycarbonate resin or polyarylate resin is preferable as the binder resin. These binder resins are used alone or in combination of two or more.
The compounding ratio of the charge transport material to the binder resin is preferably from 10:1 to 1:5 by mass.

The charge transport layer may also contain other known additives.

There are no particular restrictions on the formation of the charge transport layer, and well-known formation methods may be used. , by heating if necessary.

Examples of solvents for preparing the coating solution for forming the charge transport layer include ordinary organic solvents such as 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; and cyclic or linear ethers such as tetrahydrofuran and ethyl ether. These solvents can be used alone or in combination of two or more.

Application methods for applying the charge transport layer forming coating liquid onto the charge generation layer include blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating. Usual methods such as coating methods can be used.

The thickness of the charge transport layer is preferably set within the range of, for example, 5 μm to 50 μm, and more preferably 10 μm to 30 μm.

Hereinafter, details of the single-layer type photosensitive layer will be explained.

(Single layer type photosensitive layer)
The single-layer type photosensitive layer (charge generation/charge transport layer) is a layer containing, for example, a lubricating oil, a charge generation material, a charge transport material, and, if necessary, a binder resin and other well-known additives. be. Note that these materials are the same as those described for the charge generation layer and the charge transport layer.
The content of the charge generating material in the single-layer photosensitive layer is preferably 0.1% by mass or more and 10% by mass or less, preferably 0.8% by mass or more and 5% by mass or less based on the total solid content. . Further, the content of the charge transporting material in the single-layer type photosensitive layer is preferably 5% by mass or more and 50% by mass or less based on the total solid content.
The method for forming the single-layer type photosensitive layer is the same as the method for forming the charge generation layer and the charge transport layer.
The thickness of the single-layer type photosensitive layer is, for example, preferably 5 μm or more and 50 μm or less, preferably 10 μm or more and 40 μm or less.

[Inorganic Protective Layer]
- Composition of inorganic protective layer -
The inorganic protective layer is a layer containing an inorganic material.
Examples of inorganic materials that can be used as a protective layer include oxide-, nitride-, carbon-, and silicon-based inorganic materials, from the viewpoint of mechanical strength and light transmission.
Examples of oxide-based inorganic materials include metal oxides such as gallium oxide, aluminum oxide, zinc oxide, titanium oxide, indium oxide, tin oxide, and boron oxide, and mixed crystals of these.
Examples of the nitride-based inorganic material include metal nitrides such as gallium nitride, aluminum nitride, zinc nitride, titanium nitride, indium nitride, tin nitride, and boron nitride, and mixed crystals of these.
Examples of carbon-based and silicon-based inorganic materials include diamond-like carbon (DLC), amorphous carbon (a-C), hydrogenated amorphous carbon (a-C:H), hydrogenated/fluorinated amorphous carbon (a-C:H), amorphous silicon carbide (a-SiC), hydrogenated amorphous silicon carbide (a-SiC:H), amorphous silicon (a-Si), hydrogenated amorphous silicon (a-Si:H), etc. The inorganic material may be a mixed crystal of oxide-based and nitride-based inorganic materials.

Among the above-mentioned inorganic materials, metal oxides, especially the oxidation of Group 13 elements, are preferred because they have excellent mechanical strength and translucency, have n-type conductivity, and have excellent conductivity controllability. It is more preferable to contain an oxide of the gallium element, and even more preferably to contain gallium oxide.

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

In this embodiment, the inorganic protective layer is preferably an inorganic protective layer containing oxygen and a Group 13 element, more preferably an inorganic protective layer containing oxygen, hydrogen and a Group 13 element, and even more preferably an inorganic protective layer containing oxygen, hydrogen and a gallium element.
The inorganic protective layer has improved water repellency due to the inclusion of a Group 13 element and oxygen. This high water repellency improves the cleaning properties with a cleaning blade.
When the inorganic protective layer contains oxygen, hydrogen, and a Group 13 element, the physical properties of the inorganic protective layer can be easily controlled.

- Elemental composition ratio The elemental composition ratio of oxygen and Group 13 elements (oxygen/Group 13 element) is preferably 1.0 or more and less than 1.5, more preferably 1.1 or more and 1.5 or less, and 1. More preferably .05 or more and 1.45 or less, particularly preferably 1.10 or more and 1.40 or less.
When the elemental composition ratio of oxygen and the Group 13 element (oxygen/Group 13 element) is within the above range, the Group 13 element reacts with moisture in the atmosphere to form hydroxides (for example, gallium hydroxide), etc. Formation of the film on the surface of the inorganic protective layer at the interface between the inorganic protective layer and the photosensitive layer is suppressed. As a result, peeling of the inorganic protective layer from the photosensitive layer is further suppressed.

Sum of elemental composition ratios The sum of the elemental composition ratios of Group 13 elements (particularly gallium) and oxygen with respect to all elements constituting the inorganic surface layer is preferably 0.70 atomic % or more, more preferably 0.75 atomic % or more, even more preferably 0.80 atomic % or more, and particularly preferably 0.85 atomic % or more. When the sum of the elemental composition ratios of the Group 13 elements (particularly gallium) and oxygen is within the above range, for example, when a Group 15 element such as N, P, or As is mixed in, the influence of the mixed material bonding with the Group 13 elements (particularly gallium) is suppressed, and it becomes easier to realize an appropriate range of the oxygen and Group 13 element (particularly gallium) composition ratio (oxygen/Group 13 element (particularly gallium)) that can improve the hardness or electrical properties of the inorganic surface layer.

In the inorganic surface layer, the sum of the elemental composition ratios of Group 13 elements, oxygen, and hydrogen to all elements constituting the inorganic surface layer is preferably 90 atom % or more, more preferably 95 atom % or more, and 96 atom % or more. % or more is more preferable, and 97 atom % or more is particularly preferable.
If the sum of the elemental ratios of the Group 13 elements, oxygen, and hydrogen is within the above range, for example, when Group 15 elements such as N, P, and As are mixed, the contaminant is a Group 13 element. The composition ratio of oxygen and group 13 elements (especially gallium) (oxygen/group 13 elements (especially gallium)) can suppress the effects of combining with gallium (especially gallium) and improve the hardness and electrical properties of the inorganic surface layer. It becomes easier to find the appropriate range.

Elemental Composition Ratio When the inorganic protective layer is composed of gallium, oxygen, and optionally hydrogen, from the viewpoints of excellent mechanical strength, light transmittance, flexibility, and electrical conductivity controllability, a suitable elemental composition ratio is as follows.
The atomic ratio of gallium to all the constituent elements of the inorganic protective layer is preferably 15 atomic % to 50 atomic %, more preferably 20 atomic % to 40 atomic %, and even more preferably 20 atomic % to 30 atomic %.
The atomic ratio of oxygen to all the constituent elements of the inorganic protective layer is, for example, preferably 30 atomic % to 70 atomic %, more preferably 40 atomic % to 60 atomic %, and more preferably 45 atomic % to 55 atomic %.
The atomic ratio of hydrogen to all the constituent elements of the inorganic protective layer is, for example, preferably 10 atomic % to 40 atomic % inclusive, more preferably 15 atomic % to 35 atomic % inclusive, and more preferably 20 atomic % to 30 atomic % inclusive.
On the other hand, the atomic ratio [oxygen/gallium] is preferably more than 1.00 and not more than 2.00, and more preferably 1.10 or more and not more than 1.90.

Here, the elemental composition ratio, atomic ratio, etc. of each element in the inorganic protective layer, including the distribution in the thickness direction, are obtained by Rutherford Backscattering (hereinafter referred to as "RBS"). Note that in RBS, an NEC 3SDH Pelletron is used as the accelerator, a CE&A RBS-400 is used as the end station, and a 3S-R10 is used as the system. The CE&A HYPRA program or the like is used for the analysis.
The RBS measurement conditions are as follows: He++ ion beam energy is 2.275 eV, detection angle is 160°, and grazing angle with respect to the incident beam is approximately 109°.

Specifically, RBS measurement is performed as follows: First, a He++ ion beam is incident perpendicularly on the sample, a detector is set at 160° to the ion beam, and the backscattered He signal is measured. The composition ratio and film thickness are determined from the energy and intensity of the detected He. To improve the accuracy of determining the composition ratio and film thickness, the spectrum may be measured at two detection angles. Accuracy is improved by measuring at two detection angles with different depth resolutions and backscattering dynamics and cross-checking the results.
The number of He atoms that are backscattered by a target atom depends only on 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 calculated from the measured composition and used to calculate the thickness. The density error is within 20%.

Note that the elemental composition ratio of hydrogen is determined by hydrogen forward scattering (hereinafter referred to as "HFS").
In the HFS measurement, NEC's 3SDH Pelletron is used as an accelerator, CE&A's RBS-400 is used as an end station, and 3S-R10 is used as a system. CE&A's HYPRA program is used for analysis. The HFS measurement conditions are as follows.
・He++ ion beam energy: 2.275eV
・Detection angle: Grazing angle 30° for 160° incident beam

In HFS measurements, the detector is set at 30° to the He++ ion beam and the sample is set at 75° from the normal to pick up the signal of hydrogen scattered forward from the sample. It is advisable to cover the detector with aluminum foil to remove He atoms that scatter along with hydrogen. Quantitative analysis is performed by comparing the hydrogen counts of the reference sample and the sample to be measured after normalizing them by stopping power. A sample with H ions implanted into Si and muscovite are used as the reference sample.
Muscovite is known to have a hydrogen concentration of 6.5 atomic percent.
The amount of H adsorbed on the outermost surface is corrected by subtracting the amount of H adsorbed on a clean Si surface, for example.

The inorganic surface layer may have a distribution in composition ratio in the thickness direction depending on the purpose.
It may have a multi-layer structure.

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

The volume resistivity of the inorganic protective layer is preferably 10 ⁶ Ω·cm or more, and desirably 10 ⁸ Ω·cm or more.
When the volume resistivity is within the above range, the flow of electric charges in the in-plane direction is suppressed, and good electrostatic latent image formation is easily achieved.
This volume resistivity is calculated from the resistance value measured using an LCR meter ZM2371 manufactured by nF Corporation under conditions of a frequency of 1 kHz and a voltage of 1 V, based on the electrode area and the sample thickness.
The measurement sample may be a sample obtained by forming a film on an aluminum substrate under the same conditions as those for forming the inorganic protective layer to be measured, and then forming a gold electrode on the film by vacuum deposition, or may be a sample obtained by peeling off the inorganic protective layer from the electrophotographic photoreceptor after production, partially etching it, and sandwiching it between a pair of electrodes.

The elastic modulus of the inorganic protective layer is preferably 30 GPa or more and 80 GPa or less, preferably 40 GPa or more and 65 GPa or less.
When the elastic modulus is within the above range, the formation of recesses, peeling and cracking in the inorganic protective layer can be easily suppressed.
This elastic modulus is the average value obtained from the measured values from the indentation depth of 30 nm to 100 nm, obtained by obtaining a depth profile by the continuous stiffness method (CSM) (US Patent 4,848,141) using Nano Indenter SA2 manufactured by MTS Systems. Use. The following are the measurement conditions.
・Measurement environment: 23℃, 55%RH
・Indenter used: Diamond regular triangular pyramid indenter (Berkovic indenter) Triangular pyramid indenter ・Test mode: CSM mode The measurement sample was a sample formed on a substrate under the same conditions as the inorganic protective layer to be measured. Alternatively, it may be a sample obtained by peeling off the inorganic protective layer from the produced electrophotographic photoreceptor and partially etching it.

The thickness of the inorganic protective layer is, for example, preferably from 0.2 μm to 10.0 μm, and more preferably from 0.4 μm to 5.0 μm.
If the film thickness is within the above range, the occurrence of recesses, peeling, and cracks in the inorganic protective layer can be easily suppressed.

- Formation of inorganic protective layer -
The protective layer may be formed by a known vapor phase deposition method such as plasma CVD (Chemical Vapor Deposition), metal organic vapor phase epitaxy, molecular beam epitaxy, vapor deposition, or sputtering.

The formation of the inorganic protective layer will be described below with a specific example, with an example of a film forming apparatus shown in the drawings. Note that the following description shows a method for forming an inorganic protective layer that contains gallium, oxygen, and hydrogen, but is not limited to this, and any known formation method may be applied depending on the composition of the desired inorganic protective layer.

2 is a schematic diagram showing an example of a film forming apparatus used to form an inorganic protective layer of an electrophotographic photoreceptor according to this embodiment, in which FIG. 2(A) shows a schematic cross-sectional view of the film forming apparatus as viewed from the side, and FIG. 2(B) shows a schematic cross-sectional view of the film forming apparatus taken between A1 and A2 in FIG. 2(A). In FIG. 2, 210 is a film forming chamber, 211 is an exhaust port, 212 is a substrate rotating section, 213 is a substrate support member, 214 is a substrate, 215 is a gas introduction tube, 216 is a shower nozzle having an opening for spraying gas introduced from the gas introduction tube 215, 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 formation apparatus shown in FIG. 2 , an exhaust port 211 connected to a vacuum exhaust device (not shown) is provided at one end of the film formation chamber 210, and a plasma generating device consisting of a high-frequency power supply unit 218, a plate electrode 219, and a high-frequency discharge tube unit 221 is provided on the side opposite to the side where the exhaust port 211 is provided.
This plasma generating device is composed of a high-frequency discharge tube section 221, a plate electrode 219 arranged inside the high-frequency discharge tube section 221 with its discharge surface provided on the exhaust port 211 side, and a high-frequency power supply section 218 arranged outside the high-frequency discharge tube section 221 and connected to the surface opposite to the discharge surface of the plate electrode 219. A gas introduction pipe 220 for supplying gas into the high-frequency discharge tube section 221 is connected to the high-frequency discharge tube section 221, and the other end of this gas introduction pipe 220 is connected to a first gas supply source (not shown).

Note that the plasma generator shown in FIG. 3 may be used instead of the plasma generator provided in the film forming apparatus shown in FIG. 2. FIG. 3 is a schematic diagram showing another example of the plasma generating device used in the film forming apparatus shown in FIG. 2, and is a side view of the plasma generating device. In FIG. 3, 222 represents a high frequency coil, 223 represents a quartz tube, and 220 is the same as that shown in FIG. This plasma generator consists of a quartz tube 223 and a high-frequency coil 222 provided along the outer peripheral surface of the quartz tube 223. One end of the quartz tube 223 is connected to a film forming chamber 210 (not shown in FIG. 3). It is connected. Furthermore, 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. 2, a rod-shaped shower nozzle 216 extending along the discharge surface is connected to the discharge surface side of the flat plate electrode 219. One end of the shower nozzle 216 is connected to a gas introduction pipe 215, and this gas The introduction pipe 215 is connected to a second gas supply source (not shown) provided outside the film forming chamber 210.
In addition, a substrate rotation unit 212 is provided in the film forming chamber 210, and a cylindrical substrate 214 is attached to a substrate support member such that the longitudinal direction of the shower nozzle 216 and the axial direction of the substrate 214 face each other. It is designed to be attached to the base body rotating part 212 via 213. During film formation, the base body 214 rotates in the circumferential direction as the base body rotating section 212 rotates. Note that as the base 214, for example, a photoreceptor or the like is used, in which an organic photosensitive layer is laminated in advance.

Formation of the inorganic protective layer is performed, for example, as follows.
First, oxygen gas (or helium (He) diluted oxygen gas), helium (He) gas, and hydrogen (H ₂ ) gas as necessary are introduced into the high-frequency discharge tube section 221 from the gas introduction tube 220, and Radio waves of 13.56 MHz are supplied from the high frequency power supply section 218 to the flat plate electrode 219. At this time, the plasma diffusion portion 217 is formed to spread radially from the discharge surface side of the flat plate electrode 219 toward 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 electrode 219 side to the exhaust port 211 side. The flat plate electrode 219 may be surrounded by an earth shield.

Next, trimethyl gallium gas is introduced into the film forming chamber 210 through the gas introduction pipe 215 and the shower nozzle 216 located downstream of the flat plate electrode 219, which is an activation means, so that gallium and oxygen are formed on the surface of the substrate 214. A non-single crystal film containing hydrogen is formed.
As the base 214, for example, a base on which an organic photosensitive layer is formed is used.

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

Further, instead of trimethylgallium gas, an organometallic compound containing aluminum or a hydride such as diborane may be used, and two or more types of these may be mixed.
For example, in the initial stage of forming the inorganic protective layer, a film containing nitrogen and indium is formed on the substrate 214 by introducing trimethylindium into the film forming chamber 210 through the gas introduction pipe 215 and the shower nozzle 216. This film then absorbs ultraviolet rays that are generated during continuous film formation and degrade the organic photosensitive layer. Therefore, damage to the organic photosensitive layer due to the generation of ultraviolet rays during film formation is suppressed.

In addition, doping methods for dopants during film formation include SiH ₃ and SnH ₄ for n-type use, and biscyclopentadienylmagnesium, dimethylcalcium, dimethylstrontium, etc. in gaseous form for p-type use. use. Further, in order to dope the dopant element into the surface layer, a known method such as a thermal diffusion method or an ion implantation method may be employed.
Specifically, for example, by introducing a gas containing at least one dopant element into the film forming chamber 210 through the gas introduction pipe 215 and the shower nozzle 216, conductivity types such as n-type and p-type are introduced. Obtain an inorganic protective layer.

In the film forming apparatus described using FIGS. 2 and 3, active nitrogen or active hydrogen formed by discharge energy may be independently controlled by providing a plurality of activation devices, or it may be possible to control the active _nitrogen or active hydrogen formed by discharge energy independently. A gas containing hydrogen atoms at the same time may be used. Furthermore, _H2 may be added. Furthermore, conditions may be used that allow active hydrogen to be generated freely from the organometallic compound.
By doing so, activated carbon atoms, gallium atoms, nitrogen atoms, hydrogen atoms, and the like exist in a controlled state on the surface of the base 214. The activated hydrogen atoms have the effect of desorbing hydrogen from hydrocarbon groups such as methyl groups and ethyl groups constituting the organometallic compound as molecules.
Therefore, a hard film (inorganic protective layer) that constitutes a three-dimensional bond is formed.

The plasma generation means of the film forming apparatus shown in FIGS. 2 and 3 uses a high frequency oscillation device, but is not limited to this. For example, a microwave oscillation device may be used, or an electromagnetic A cyclotron resonance type or helicon plasma type device may also be used. Furthermore, in the case of a high frequency oscillation device, it may be of an inductive type or a capacitive type.
Furthermore, two or more types of these devices may be used in combination, or two or more of the same type of devices may be used. Although a high frequency oscillator is desirable for suppressing the temperature rise on the surface of the base 214 due to plasma irradiation, a device for suppressing heat irradiation may be provided.

When using two or more different types of plasma generating devices (plasma generating means), it is desirable to have them generate discharges simultaneously at the same pressure. Also, a pressure difference may be provided between the discharge area and the film-forming area (the area where the substrate is placed). These devices may be arranged in series with respect to the gas flow that is formed inside the film-forming device from the area where the gas is introduced to the area where it is exhausted, or each device may be arranged to face the film-forming surface of the substrate.

For example, when two types of plasma generating means are installed in series with respect to the gas flow, in the case of the film formation apparatus shown in Fig. 2, the shower nozzle 216 is used as an electrode to generate a discharge in the film formation chamber 210. In this case, for example, a high frequency voltage is applied to the shower nozzle 216 via the gas introduction pipe 215 to generate a discharge in the film formation chamber 210 using the shower nozzle 216 as an electrode. Alternatively, instead of using the shower nozzle 216 as an electrode, a cylindrical electrode is provided between the substrate 214 and the plate electrode 219 in the film formation chamber 210, and this cylindrical electrode is used to generate a discharge in the film formation chamber 210.
In addition, 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 changed significantly, which is effective in controlling the film quality. Discharge may be performed near atmospheric pressure (70,000 Pa or more and 110,000 Pa or less). When discharge is performed near atmospheric pressure, it is desirable to use He as a carrier gas.

The inorganic protective layer is formed, for example, by placing a substrate 214 having an organic photosensitive layer formed on the substrate in the film formation chamber 210, and introducing mixed gases having different compositions to form the inorganic protective layer.

Further, as the film forming conditions, for example, when discharging by high frequency discharge, in order to form a high quality film at low temperature, it is desirable that the frequency is in the range of 10 kHz or more and 50 MHz or less. Further, although the output depends on the size of the base 214, it is preferably in the range of 0.01 W/cm ² or more and 2 W/cm ² or less relative to the surface area of the base. The rotational speed of the base 214 is preferably in the range of 0.1 rpm or more and 1000 rpm or less.

[Conductive substrate]
Examples of the conductive substrate include metal plates, metal drums, and metal belts containing metals (aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.). can be mentioned. Examples of conductive substrates include paper, resin films, belts, etc. coated with, vapor-deposited, or laminated with conductive compounds (e.g., conductive polymers, indium oxide, etc.), metals (e.g., aluminum, palladium, gold, etc.), or alloys. can also be mentioned. Here, "conductivity" means that the volume resistivity is less than 10 ¹³ Ωcm.

When the electrophotographic photoreceptor is used in 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 that occur when irradiated with laser light. It is preferable that the surface be roughened. Note that when incoherent light is used as a light source, surface 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 unevenness on the surface of the conductive substrate.

Methods for roughening the surface include, for example, wet honing, in which an abrasive is suspended in water and sprayed onto the conductive substrate; centerless grinding, in which the conductive substrate is pressed against a rotating grindstone and continuously ground; and anodizing.

As a method of roughening, there is also a method in which, without roughening the surface of the conductive substrate, conductive or semiconductive powder is dispersed in a resin to form a layer on the surface of the conductive substrate, and the surface is roughened by the particles dispersed in the layer.

In the roughening treatment by anodization, an oxide film is formed on the surface of a conductive substrate made of metal (e.g., aluminum) by anodizing the substrate in an electrolyte solution using the substrate as the anode. Examples of electrolyte solutions include sulfuric acid solution and oxalic acid solution. However, the porous anodic oxide film formed by anodization is chemically active in its original state, easily contaminated, and has a large resistance fluctuation due to the environment. Therefore, it is preferable to perform a sealing treatment on the porous anodic oxide film, in which the micropores of the oxide film are filled by volume expansion caused by a hydration reaction in pressurized steam or boiling water (metal salts such as nickel may be added), and the porous anodic oxide film is converted into a more stable hydrated oxide.

The thickness of the anodic oxide film is preferably, for example, 0.3 μm or more and 15 μm or less. When the film thickness is within the above range, barrier properties against injection tend to be exhibited, and increases in residual potential due to repeated use tend to be suppressed.

The conductive substrate may be subjected to a treatment with an acidic treatment solution or a boehmite treatment.
Treatment with an acidic treatment solution is carried out, for example, as follows. First, an acidic treatment solution containing phosphoric acid, chromic acid, and hydrofluoric acid is prepared. The mixing ratios of phosphoric acid, chromic acid, and hydrofluoric acid in the acidic treatment solution are, for example, phosphoric acid in the range of 10 mass% to 11 mass%, chromic acid in the range of 3 mass% to 5 mass%, and hydrofluoric acid in the range of 0.5 mass% to 2 mass%, and the total concentration of these acids is preferably in the range of 13.5 mass% to 18 mass%. The treatment temperature is preferably, for example, 42°C to 48°C. The film thickness of the coating is preferably 0.3 μm to 15 μm.

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

[Sublayer]
The subbing layer is, for example, a layer containing inorganic particles and a binder resin.

The inorganic particles may, for example, have a powder resistivity (volume resistivity) of 10 ² Ωcm or more and 10 ¹¹ Ωcm or less.
Among these, examples of inorganic particles having the above-mentioned resistance value include metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles, and zinc oxide particles are particularly preferred.

The specific surface area of the inorganic particles as measured by the BET method is preferably, for example, 10 m ² /g or more.
The volume average particle size of the inorganic particles is, for example, from 50 nm to 2000 nm (preferably from 60 nm to 1000 nm).

The content of inorganic particles is, for example, preferably 10% by mass or more and 80% by mass or less, and more preferably 40% by mass or more and 80% by mass or less, relative to the binder resin.

The inorganic particles may be surface-treated. Two or more types of inorganic particles with different surface treatments or different particle sizes may be used as a mixture.

Examples of surface treatment agents include silane coupling agents, titanate coupling agents, aluminum coupling agents, surfactants, etc. In particular, silane coupling agents are preferred, and silane coupling agents having an amino group are more preferred.

Examples of silane coupling agents having an amino group include, but are not limited to, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane.

Two or more types of silane coupling agents may be used in combination. For example, a silane coupling agent having an amino group and another silane coupling agent may be used together. Examples of other silane coupling agents include vinyltrimethoxysilane, 3-methacryloxypropyl-tris(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-glyoxypropyl-tris(2-methoxyethoxy)silane. Sidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-( Examples include, but are not limited to, aminoethyl)-3-aminopropylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, and 3-chloropropyltrimethoxysilane. It's not a thing.

The surface treatment method using the surface treatment agent may be any known method, and may be either a dry method or a wet method.

The amount of the surface treatment agent is preferably, for example, 0.5% by mass or more and 10% by mass or less relative to the inorganic particles.

Here, it is preferable for the undercoat layer to contain an electron-accepting compound (acceptor compound) together with inorganic particles, from the viewpoint of improving long-term stability of electrical properties and carrier blocking properties.

Examples of the electron-accepting compound include electron-transporting substances such as quinone compounds such as chloranil and bromoanil; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone; oxadiazole compounds such as 2-(4-biphenyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole, 2,5-bis(4-naphthyl)-1,3,4-oxadiazole and 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole; xanthone compounds; thiophene compounds; and diphenoquinone compounds such as 3,3',5,5'-tetra-t-butyldiphenoquinone.
In particular, the electron-accepting compound is preferably a compound having an anthraquinone structure, such as a hydroxyanthraquinone compound, an aminoanthraquinone compound, or an aminohydroxyanthraquinone compound, and more specifically, such as anthraquinone, alizarin, quinizarin, anthraphine, or purpurin.

The electron accepting compound may be dispersed together with the inorganic particles in the undercoat layer, or may be attached to the surface of the inorganic particles.

Methods for attaching an electron-accepting compound to the surface of inorganic particles include, for example, a dry method or a wet method.

The dry method is a method in which, for example, while stirring inorganic particles with a mixer or the like that exerts a large shearing force, an electron-accepting compound is dropped directly or dissolved in an organic solvent, or sprayed together with dry air or nitrogen gas, to adhere the electron-accepting compound to the surface of the inorganic particles. When dropping or spraying the electron-accepting compound, it is preferable to do so at a temperature below the boiling point of the solvent. After dropping or spraying the electron-accepting compound, baking may be performed at 100°C or higher. There are no particular limitations on the temperature and time of baking, so long as electrophotographic properties can be obtained.

The wet method is a method in which inorganic particles are dispersed in a solvent, for example, by stirring, ultrasonic waves, a sand mill, an attritor, a ball mill, etc., while an electron-accepting compound is added, and after stirring or dispersing, the solvent is removed to attach the electron-accepting compound to the surface of the inorganic particles. The solvent is removed, for example, by filtration or distillation. After the solvent is removed, baking may be performed at 100°C or higher. There are no particular limitations on the temperature and time for baking, so long as electrophotographic properties are obtained. In the wet method, moisture contained in the inorganic particles may be removed before the electron-accepting compound is added. Examples of such methods include a method in which the moisture is removed while stirring and heating in a solvent, and a method in which the moisture is removed by azeotropy with the solvent.

Note that the electron-accepting compound may be attached before or after the inorganic particles are subjected to surface treatment with a surface treatment agent, or may be carried out simultaneously with the attachment of the electron-accepting compound and the surface treatment with the surface treatment agent.

The content of the electron-accepting compound is, for example, 0.01% by mass or more and 20% by mass or less, and preferably 0.01% by mass or more and 10% by mass or less, relative to the inorganic particles.

Examples of the binder resin used in the undercoat layer include known materials such as acetal resins (e.g., polyvinyl butyral, etc.), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, unsaturated polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, urea resins, phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, alkyd resins, and epoxy resins; zirconium chelate compounds; titanium chelate compounds; aluminum chelate compounds; titanium alkoxide compounds; organic titanium compounds; and silane coupling agents.
Examples of the binder resin used in the undercoat layer include charge transporting resins having charge transporting groups, conductive resins (such as polyaniline), and the like.

Among these, as the binder resin used in the undercoat layer, a resin insoluble in the coating solvent of the upper layer is preferred, and in particular, a resin obtained by reacting at least one resin selected from the group consisting of a thermosetting resin such as a urea resin, a phenol resin, a phenol-formaldehyde resin, a melamine resin, a urethane resin, an unsaturated polyester resin, an alkyd resin, and an epoxy resin with a curing agent is preferred.
When two or more of these binder resins are used in combination, the mixing ratio thereof is set as required.

The undercoat layer may contain various additives for improving electrical properties, environmental stability, and image quality.
Examples of the additives include known materials such as polycyclic condensation and azo-based electron transport pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, silane coupling agents, etc. As described above, silane coupling agents are used for surface treatment of inorganic particles, and may also be added to the undercoat layer as an additive.

Examples of the silane coupling agent as an additive include vinyltrimethoxysilane, 3-methacryloxypropyl-tris(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3- Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2- Examples include (aminoethyl)-3-aminopropylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, and 3-chloropropyltrimethoxysilane.

Examples of zirconium chelate compounds include zirconium butoxide, zirconium ethyl acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, acetoacetate ethyl zirconium butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide, and the like.

Examples of titanium chelate compounds include tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, and titanium lactate ammonium salt. , titanium lactate, titanium lactate ethyl ester, titanium triethanolaminate, polyhydroxytitanium stearate, and the like.

Examples of aluminum chelate compounds include aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate, diethylacetoacetate aluminum diisopropylate, and aluminum tris(ethylacetoacetate).

These additives may be used alone or as a mixture or polycondensation of multiple compounds.

The undercoat layer preferably has a Vickers hardness of 35 or more.
The surface roughness (ten-point average roughness) of the undercoat layer ranges from 1/(4n) (n is the refractive index of the upper layer) to 1/2 of the exposure laser wavelength λ used to suppress moiré images. It is good to have it adjusted to
Resin particles or the like may be added to the undercoat layer to adjust the surface roughness. Examples of the resin particles include silicone resin particles and crosslinked polymethyl methacrylate resin particles. Further, the surface of the undercoat layer may be polished to adjust the surface roughness. Examples of the polishing method include buffing, sandblasting, wet honing, and grinding.

There are no particular limitations on the formation of the undercoat layer, and any known formation method can be used. For example, the undercoat layer can be formed by forming a coating film of a coating solution for forming the undercoat layer in which the above components are added to a solvent, drying the coating film, and heating it as necessary.

Examples of the solvent for preparing the coating liquid for forming the undercoat layer include known organic solvents, such as alcohol-based solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone-based solvents, ketone alcohol-based solvents, ether-based solvents, and ester-based solvents.
Specific examples of these solvents include ordinary organic solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene.

Examples of methods for dispersing inorganic particles when preparing a coating solution for forming an undercoat layer include known methods such as a roll mill, a ball mill, a vibrating ball mill, an attriter, a sand mill, a colloid mill, and a paint shaker.

Methods for applying the coating liquid for forming the undercoat layer onto the conductive substrate include, for example, conventional methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

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

[Middle layer]
Although not shown, an intermediate layer may be further provided between the undercoat layer and the photosensitive layer.
The intermediate layer is, for example, a layer containing resin. Examples of the resin used for the intermediate layer include acetal resin (e.g., polyvinyl butyral), polyvinyl alcohol resin, polyvinyl acetal resin, casein resin, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, Examples include polymeric compounds such as polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, and melamine resin.
The intermediate layer may be a layer containing an organometallic compound. Examples of the organometallic compound used in the intermediate layer include organometallic compounds containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon.
The compounds used in these intermediate layers may be used alone or as a mixture or polycondensate of a plurality of compounds.

Among these, the intermediate layer is preferably a layer containing an organometallic compound containing a zirconium atom or a silicon atom.

The formation of the intermediate layer is not particularly limited, and a well-known formation method can be used. For example, the intermediate layer can be formed by forming a coating film of a coating solution for forming an intermediate layer in which the above components are added to a solvent, drying the coating film, and heating it if necessary.
The intermediate layer can be formed by any of the usual coating methods, such as dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating and curtain coating.

The thickness of the intermediate layer is, for example, preferably set in a range of 0.1 μm or more and 3 μm or less. Note that the intermediate layer may be used as a subbing layer.

<Image forming apparatus (and process cartridge)>
The image forming apparatus according to the present embodiment includes an electrophotographic photoreceptor, a charging unit that charges the surface of the electrophotographic photoreceptor, and an electrostatic latent image forming device that forms an electrostatic latent image on the surface of the charged electrophotographic photoreceptor. a developing means for forming a toner image by developing an electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing toner; and a transfer means for transferring the toner image onto the surface of the recording medium; Equipped with The electrophotographic photoreceptor according to the present embodiment is applied as the electrophotographic photoreceptor.

The image forming apparatus according to this embodiment may be any of known image forming apparatuses, such as an apparatus equipped with a fixing unit that fixes a toner image transferred to the surface of a recording medium; an apparatus using a direct transfer method that directly transfers a toner image formed on the surface of an electrophotographic photoreceptor to a recording medium; an apparatus using an intermediate transfer method that performs a primary transfer of a toner image formed on the surface of an electrophotographic photoreceptor to the surface of an intermediate transfer body, and a secondary transfer of the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium; an apparatus equipped with a cleaning unit that cleans the surface of an electrophotographic photoreceptor before charging after the transfer of a toner image; an apparatus equipped with a discharging unit that irradiates a discharging light onto the surface of an electrophotographic photoreceptor before charging after the transfer of a toner image to discharging the surface; and an apparatus equipped with an electrophotographic photoreceptor heating member for increasing the temperature of the electrophotographic photoreceptor and reducing the relative temperature.

In the case of an intermediate transfer type device, the transfer means is configured to have, for example, an intermediate transfer body onto whose surface a toner image is transferred, a primary transfer means which primarily transfers the toner image formed on the surface of the electrophotographic photoreceptor onto the surface of the intermediate transfer body, and a secondary transfer means which secondarily transfers the toner image transferred onto the surface of the intermediate transfer body onto the surface of the recording medium.

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

In the image forming apparatus according to the present embodiment, for example, the portion including the electrophotographic photoreceptor may have a cartridge structure (process cartridge) that is detachable from the image forming apparatus. As the process cartridge, for example, a process cartridge including the electrophotographic photoreceptor according to this embodiment is suitably used. In addition to the electrophotographic photoreceptor, the process cartridge may also include, for example, at least one selected from the group consisting of charging means, electrostatic latent image forming means, developing means, and transfer means.

An example of an image forming apparatus according to this embodiment will be shown below, but the present invention is not limited thereto. Note that the main parts shown in the figure will be explained, and the explanation of the others will be omitted.

FIG. 4 is a schematic configuration diagram showing an example of an image forming apparatus according to this embodiment.
As shown in FIG. 4, the image forming apparatus 100 according to the present embodiment includes a process cartridge 300 including an electrophotographic photoreceptor 7, an exposure device 9 (an example of electrostatic latent image forming means), and a transfer device 40 (primary (transfer device) and an intermediate transfer body 50. In the image forming apparatus 100, the exposure device 9 is arranged at a position where it can expose the electrophotographic photoreceptor 7 from the opening of the process cartridge 300, and the transfer device 40 exposes the electrophotographic photoreceptor 7 via the intermediate transfer member 50. The intermediate transfer body 50 is disposed at a position opposite to the electrophotographic photoreceptor 7 , and a portion of the intermediate transfer body 50 is disposed in contact with the electrophotographic photoreceptor 7 . Although not shown, it also includes a secondary transfer device that transfers the toner image transferred to the intermediate transfer member 50 onto a recording medium (for example, paper). Note that 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 apparatus 60 (an example of a control means) is a device that controls the operation of each device and each member in the image forming apparatus 100, and is arranged to be connected to each device and each member. ing.

The process cartridge 300 in FIG. 4 supports the electrophotographic photoreceptor 7, the charging device 8 (an example of a charging means), the developing device 11 (an example of a developing means), and the cleaning device 13 (an example of a cleaning means) in a housing. The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131, which is arranged so as to contact the surface of the electrophotographic photoreceptor 7. The cleaning member may be a conductive or insulating fibrous member instead of the cleaning blade 131, and may be used alone or in combination with the cleaning blade 131.

In addition, FIG. 4 shows an example of an image forming device equipped with a fibrous member 132 (roll-shaped) that supplies lubricant 14 to the surface of electrophotographic photoreceptor 7, and a fibrous member 133 (flat brush-shaped) that assists in cleaning, but these are arranged as necessary.

Each configuration of the image forming apparatus according to this embodiment will be described below.

-Charging device-
As the charging device 8, for example, a contact type charger using a conductive or semiconductive charging roller, charging brush, charging film, charging rubber blade, charging tube, etc. Also, a non-contact type roller charger, a scorotron charger or corotron charger that utilizes corona discharge, or other chargers known per se, can be used.

--Exposure equipment--
The exposure device 9 may be, for example, an optical device that exposes the surface of the electrophotographic photoreceptor 7 with light such as semiconductor laser light, LED light, or liquid crystal shutter light in a predetermined image. The wavelength of the light source is within the spectral sensitivity range of the electrophotographic photoreceptor. The wavelength of the semiconductor laser is mainly near infrared light having an oscillation wavelength of about 780 nm. However, it is not limited to this wavelength, and a laser having an oscillation wavelength of 600 nm or more or a blue laser having an oscillation wavelength of 400 nm or more and 450 nm or less may also be used. In addition, a surface-emitting type laser light source capable of outputting multiple beams is also effective for forming a color image.

-Developing device-
The developing device 11 may be, for example, 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 may be selected according to the purpose. For example, it may be a known developing device that has a function of attaching a one-component developer or a two-component developer to the electrophotographic photoreceptor 7 using a brush, roller, or the like.
Among these, it is preferable to use a developing roller having a developer held on its surface.

The developer used in the developing device 11 may be a one-component developer containing only toner, or a two-component developer containing toner and a carrier. The developer may be magnetic or non-magnetic. Well-known developers are used.

-Cleaning device-
The cleaning device 13 is a cleaning blade type device equipped with a cleaning blade 131 .
In addition to the cleaning blade system, a fur brush cleaning system or a simultaneous development and cleaning system may also be used.

-Transfer device-
As the transfer device 40, for example, a contact type transfer charger using a belt, a roller, a film, a rubber blade, etc., a scorotron transfer charger or a corotron transfer charger using corona discharge, and other known transfer chargers are used. Can be mentioned.

- Intermediate transfer body -
A belt-like intermediate transfer belt containing semiconductive polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber, or the like is used as the intermediate transfer body 50. The intermediate transfer body may be in the form of a drum other than a belt.

-Control device-
The control device 60 is configured as a computer that controls the entire device and performs various calculations. Specifically, the control device 60 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores various programs, a RAM (Random Access Memory) that is used as a work area when the programs are executed, a non-volatile memory that stores 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 device 100, such as the electrophotographic photosensitive member 7 (including the driving 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.

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

The control device 60 may also be connected to various drives. Examples of the various drives include devices that read data from and write data to portable computer-readable recording media such as flexible disks, optical magnetic disks, CD-ROMs, DVD-ROMs, and USB (Universal Serial Bus) memories. When the control device 60 is provided with various drives, a control program may be recorded on a portable recording medium and then read and executed by a corresponding drive.

FIG. 5 is a schematic configuration diagram showing another example of the image forming apparatus according to this embodiment.
The image forming apparatus 120 shown in FIG. 5 is a tandem 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 member 50, and one electrophotographic photoreceptor is used for each color. Note that the image forming apparatus 120 has the same configuration as the image forming apparatus 100 except that it is of a tandem type.

The image forming apparatus 100 according to the present embodiment is not limited to the above configuration, and may have, for example, a first discharging device for aligning the polarity of residual toner and facilitating removal by a cleaning brush, provided around the electrophotographic photoreceptor 7 downstream of the transfer device 40 in the direction of rotation of the electrophotographic photoreceptor 7 and upstream of the cleaning device 13 in the direction of rotation of the electrophotographic photoreceptor, or a second discharging device for discharging the surface of the electrophotographic photoreceptor 7, provided downstream of the cleaning device 13 in the direction of rotation of the electrophotographic photoreceptor and upstream of the charging device 8 in the direction of rotation of the electrophotographic photoreceptor.

In addition, the image forming apparatus 100 according to this embodiment is not limited to the above configuration, and may adopt a well-known configuration, for example, a direct transfer type image forming apparatus in which a toner image formed on the electrophotographic photoreceptor 7 is directly transferred to a recording medium.

The present invention will be described in more detail below based on examples, but the present invention is not limited to the following examples. The materials, amounts used, ratios, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of this disclosure. Note that "parts" means "parts by mass" unless otherwise specified.

[Example 1]
- Preparation of undercoat layer -
100 parts by mass of zinc oxide (average particle size 70 nm: manufactured by Teica Corporation; specific surface area value 15 ^m2 /g) was mixed with 500 parts by mass of tetrahydrofuran and stirred, and 1.3 parts by mass of a silane coupling agent (KBM503: manufactured by Shin-Etsu Chemical Co., Ltd.) was added and stirred for 2 hours. Thereafter, the tetrahydrofuran was distilled off under reduced pressure, and the mixture was baked at 120°C for 3 hours to obtain zinc oxide surface-treated with a silane coupling agent.

110 parts by mass of the zinc oxide that had been subjected to the surface treatment (zinc oxide surface-treated with a silane coupling agent) was mixed with 500 parts by mass of tetrahydrofuran and stirred, and a solution in which 0.6 parts by mass of alizarin was dissolved in 50 parts by mass of tetrahydrofuran was added, and the mixture was stirred at 50°C for 5 hours. The zinc oxide to which alizarin had been added was then filtered out by vacuum filtration, and further dried at 60°C under reduced pressure to obtain zinc oxide to which alizarin had been added.

A mixture was obtained by mixing 60 parts by mass of this alizarin-added zinc oxide, 13.5 parts by mass of a curing agent (blocked isocyanate Sumidur 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.), 15 parts by mass of a butyral resin (S-LEC BM-1, manufactured by Sekisui Chemical Co., Ltd.), and 85 parts by mass of methyl ethyl ketone. 38 parts by mass of this mixture was mixed with 25 parts by mass of methyl ethyl ketone, and the mixture was dispersed in a sand mill using 1 mm diameter glass beads for 2 hours to obtain a dispersion.

To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate and 40 parts by mass of silicone resin particles (Tospearl 145, manufactured by Momentive Performance Materials) were added as a catalyst to form an undercoat layer. A coating solution was obtained. This coating solution was applied by dip coating onto an aluminum substrate with a diameter of 60 mm, a length of 357 mm, and a wall thickness of 1 mm, and dried and cured at 170° C. for 40 minutes to obtain a subbing layer with a thickness of 19 μm.

-Preparation of charge generation layer-
Positions where the Bragg angle (2θ±0.2°) of an X-ray diffraction spectrum using Cukα characteristic X-rays as a charge generating substance is at least 7.3°, 16.0°, 24.9°, or 28.0° A mixture consisting of 15 parts by mass of hydroxygallium phthalocyanine having a diffraction peak at The mixture was dispersed in a sand mill for 4 hours using glass beads of 1 mm diameter. 175 parts by weight of n-butyl acetate and 180 parts by weight of methyl ethyl ketone were added to the resulting dispersion and stirred to obtain a coating liquid for forming a charge generation layer. This coating solution for forming a charge generation layer was applied onto the undercoat layer by dip coating and dried at room temperature (25° C.) to form a charge generation layer having a thickness of 0.2 μm.

-Preparation of charge transport layer-
Add 250 parts by mass of tetrahydrofuran to inorganic particles of the type and amount shown in Table 1, and use 4-(2,2-diphenylethyl)-4',4''-dimethyl as a charge transport material while keeping the liquid temperature at 20°C. - Add 25 parts by mass of triphenylamine, 25 parts by mass of bisphenol Z type polycarbonate resin (viscosity average molecular weight: 30,000) as a binder resin, and lubricating oil of the type shown in Table 1, stir and mix for 12 hours, and charge A coating solution for forming a transport layer was obtained. The lubricating oil was blended in the amount shown in Table 1 based on the total solid content of the photosensitive layer.
Then, this coating liquid for forming a charge transport layer was applied onto the charge generation layer and dried at 135° C. for 40 minutes to form a charge transport layer having a thickness of 30 μm.

- Formation of inorganic protective layer -
An inorganic protective layer made of gallium oxide containing hydrogen was formed on the surface of the charge transport layer. This inorganic protective layer was formed using a film forming apparatus having the configuration shown in FIG.

First, the organic photoreceptor 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 reached 0.1 Pa.
Next, 40% oxygen gas diluted with He (flow rate 1.8 sccm) and hydrogen gas (flow rate 50 sccm) are introduced from the gas introduction tube 220 into the high frequency discharge tube section 221 in which the flat plate electrode 219 with a diameter of 85 mm is provided. A radio frequency of 13.56 MHz was set to an output of 150 W using the high frequency power supply section 218 and a matching circuit (not shown in FIG. 4), and matching was performed using a tuner to cause discharge from the flat plate electrode 219. The reflected wave at this time was 0W.
Next, trimethyl gallium gas (flow rate: 1.9 sccm) was introduced into the plasma diffusion section 217 in the film forming chamber 210 from the shower nozzle 216 via the gas introduction pipe 215. At this time, the reaction pressure inside the film forming chamber 210 measured with a Baratron vacuum gauge was 5.3 Pa.
In this state, a film was formed for 900 minutes while rotating the organic photoreceptor at a speed of 500 rpm to form an inorganic protective layer with a thickness of 3.0 μm on the surface of the charge transport layer of the organic photoreceptor. The surface roughness Ra of the outer peripheral surface of the inorganic protective layer was 1.9 nm. The elemental composition ratio of oxygen and gallium (oxygen/gallium) in the inorganic protective layer was 1.3.

Through the above steps, an electrophotographic photoreceptor of Example 1 was obtained in which an undercoat layer, a charge generating layer, a charge transport layer, and an inorganic protective layer were formed in sequence on a conductive substrate.

[Examples 2 to 12 and Comparative Examples 1 and 2]
The electrophotographic photoreceptors of each example were obtained in the same manner as in Example 1, except that the type and amount of inorganic particles, the type and amount of lubricating oil contained in the photosensitive layer, and the elemental composition ratio of oxygen/gallium in the inorganic protective layer were set to the specifications shown in Table 1.

Details of each material used in each example are provided below.
(1) Materials of inorganic particles Silica particles: RX50, manufactured by Nippon Aerosil Co., Ltd. (2) Materials of lubricating oil Silicone oil: toluene solution of dimethylpolysiloxane, KP-340, manufactured by Shin-Etsu Silicone Co., Ltd. Silicone oil: methylphenylpolysiloxane, KF-50, manufactured by Shin-Etsu Silicone Co., Ltd. Silicone oil: acrylic modified silicone oil, KP-541, manufactured by Shin-Etsu Silicone Co., Ltd. Fluorine-containing oil: fluorine-containing acrylic polymer, S-651, manufactured by AGC Inc. Fluorine-containing oil: fluorine-containing acrylic polymer, LE-604, manufactured by Kyoei Chemical Co., Ltd. Silicone oil: lubricant other than fluorine-containing oil: polyalphaolefin, PAO201, manufactured by Nippon Steel Chemical & Material Co., Ltd. Silicone oil: carbinol modified silicone oil, KF-6000, manufactured by Shin-Etsu Silicone Co., Ltd.

Table 1 shows the values of the elemental composition ratios of oxygen and Group 13 elements (oxygen/Group 13 elements) measured by the above-mentioned measuring method for the electrophotographic photoreceptors of each example.

In Table 1, "-" in each item means that the material of each item is not included.
In Table 1, "% by mass" in the item of inorganic particles means the content of silica particles with respect to the total solid content of the photosensitive layer.
In Table 1, "water contact angle" in the photosensitive layer section means the value of the water contact angle on the surface on the interface side with the inorganic protective layer.

<Evaluation of peelability>
The evaluation image forming apparatus (Versante 1800 Press, manufactured by Fujifilm Business Innovation Co., Ltd.) equipped with the electrophotographic photoreceptor of each example was stored for 3 days in a high temperature and high humidity environment (28°C/85%). The removability was evaluated by visually determining the surface condition after storage. The evaluation results are shown in Table 1. Note that A to B are acceptable.
-Evaluation criteria-
A: No peeling.
B: Lifting is observed in some areas, but no peeling occurs and is within an acceptable range.
C: Peeling from some areas.
D: Peeling from multiple areas.

As shown in Table 1, it was found that the electrophotographic photoreceptor of the example suppressed peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer, compared to the electrophotographic photoreceptor of the comparative example.

(((1))) A conductive substrate;
a photosensitive layer provided on the conductive substrate;
an inorganic protective layer provided on the photosensitive layer;
having
the photosensitive layer has a water contact angle of 82° or more on the surface at the interface with the inorganic protective layer, and the content of silica particles relative to the total solid content of the photosensitive layer is 0% by mass or 20% by mass or less.
(((2))) The electrophotographic photoreceptor according to (((1))), wherein the photosensitive layer contains a lubricating oil in an amount of 0.0001% by mass or more based on the total solid content of the photosensitive layer.
(((3))) The electrophotographic photoreceptor according to (((2))), wherein the lubricating oil contains at least one of a silicone oil and a fluorine-containing oil.
(((4))) The electrophotographic photoreceptor according to (((3))), wherein the lubricating oil contains the silicone oil.
(((5))) The electrophotographic photoreceptor according to any one of (((1))) to (((4))), wherein the inorganic protective layer is an inorganic protective layer containing oxygen, hydrogen and a Group 13 element.
(((6))) The electrophotographic photoreceptor according to (((5))), wherein the inorganic protective layer has an element composition ratio of oxygen and Group 13 element (oxygen/Group 13 element) of 1.1 or more and 1.5 or less.
(((7))) a conductive substrate;
a photosensitive layer provided on the conductive substrate;
an inorganic protective layer provided on the photosensitive layer;
having
the photosensitive layer contains a lubricating oil in an amount of 0.0001% by mass or more relative to the total solid content of the photosensitive layer, and the content of silica particles in the total solid content of the photosensitive layer is 0% by mass or 20% by mass or less.
(((8))) An electrophotographic photoreceptor according to any one of (((1))) to (((7))),
A process cartridge that is detachably attached to an image forming apparatus.
(((9))) The electrophotographic photoreceptor according to any one of (((1))) to (((7))),
a charging means for charging the surface of the electrophotographic photoreceptor;
an electrostatic latent image forming means for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;
a developing unit for developing an electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image;
a transfer means for transferring the toner image onto a surface of a recording medium;
An image forming apparatus comprising:

According to the invention related to ((1))) or ((5))), there is provided an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed, as compared to when the water contact angle of the surface of the photosensitive layer on the interface side with the inorganic protective layer is less than 82°.
According to the invention related to (((2))), there is provided an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed, as compared to when the photosensitive layer contains less than 0.0001 mass % of a lubricating oil relative to the total solids content of the photosensitive layer.
According to the invention pertaining to (((3))) or (((4))), there is provided an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed, compared to when the lubricating oil is XXX.
According to the invention related to (((6))), there is provided an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed, as compared with a case in which the elemental composition ratio of oxygen and Group 13 element (oxygen/Group 13 element) in the inorganic protective layer is less than 1.1 or exceeds 1.5.

According to the invention related to (((7))), there is provided an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed, as compared to a case in which the photosensitive layer contains 0 mass % or less than 0.0001 mass % of a lubricating oil relative to the total solids content of the photosensitive layer.
According to the invention related to ((8))) or ((9)), there is provided a process cartridge and an image forming apparatus including an electrophotographic photoreceptor in which peeling of an inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed compared to when the photosensitive layer "contains 0 mass % or less than 0.0001 mass % of a lubricating oil relative to the total solids content of the photosensitive layer" or "when the water contact angle on the surface on the interface side with the inorganic protective layer is less than 82°".

According to the invention related to ((1))) or ((5))), there is provided an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed, as compared to when the water contact angle of the surface of the photosensitive layer on the interface side with the inorganic protective layer is less than 82°.
According to the invention related to (((2))), there is provided an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed, as compared to when the photosensitive layer contains less than 0.0001 mass % of a lubricating oil relative to the total solids content of the photosensitive layer.
According to the invention related to (((3))) or (((4))), there is provided an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed, compared to when the lubricating oil is a polyalphaolefin-based lubricating oil, which is a type of hydrocarbon-based synthetic oil.
According to the invention related to (((6))), there is provided an electrophotographic photoreceptor in which peeling of the inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed, as compared with a case in which the elemental composition ratio of oxygen and Group 13 element (oxygen/Group 13 element) in the inorganic protective layer is less than 1.1 or exceeds 1.5.

According to the invention according to ((7))), compared to the case where the photosensitive layer contains lubricating oil in an amount of 0% by mass or less than 0.0001% by mass based on the total solid content of the photosensitive layer, An electrophotographic photoreceptor is provided in which peeling of an inorganic protective layer from the surface of the photosensitive layer on the interface side with the inorganic protective layer is suppressed.
According to the invention according to (((8))) or (((9))), the photosensitive layer contains "0% by mass or less than 0.0001% by mass of lubricating oil based on the total solid content of the photosensitive layer. or "the water contact angle on the surface on the interface side with the inorganic protective layer is less than 82°", A process cartridge and an image forming apparatus are provided that include an electrophotographic photoreceptor in which peeling of a protective layer is suppressed.

101 undercoat layer, 102 charge generation layer, 103 charge transport layer, 104 conductive substrate, 105 organic photosensitive layer, 106 inorganic protective layer, 107A, 7 electrophotographic photosensitive member (photosensitive member), 8 charging device, 9 exposure device, 11 developing device, 13 cleaning device, 14 lubricant, 30 drive motor, 40 transfer device, 50 intermediate transfer body, 60 control device, 100 image forming apparatus, 120 image forming apparatus, 131 cleaning blade, 132 fibrous member (roll-shaped), 133 fibrous member (flat brush-shaped), 300 process cartridge, 210 film formation chamber, 211 exhaust port, 212 substrate rotation section, 213 substrate support member, 214 substrate, 215, 220 gas introduction tube, 216 shower nozzle, 217 plasma diffusion section, 218 High frequency power supply unit, 219 flat electrode, 221 high frequency discharge tube unit, 222 high frequency coil, 223 quartz tube

Claims (9)

a conductive substrate;
a photosensitive layer provided on the conductive substrate;
an inorganic protective layer provided on the photosensitive layer;
has
The photosensitive layer has a water contact angle of 82° or more on the surface on the interface side with the inorganic protective layer, and the content of silica particles is 0% by mass or 20% by mass or less based on the total solid content of the photosensitive layer. An electrophotographic photoreceptor. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains lubricating oil in an amount of 0.0001% by mass or more based on the total solid content of the photosensitive layer. The electrophotographic photoreceptor according to claim 2, wherein the lubricating oil includes at least one of silicone oil and fluorine-containing oil. The electrophotographic photoreceptor according to claim 3, wherein the lubricating oil includes the silicone oil. The electrophotographic photoreceptor according to claim 1, wherein the inorganic protective layer is an inorganic protective layer containing oxygen, hydrogen, and a Group 13 element. The electrophotographic photoreceptor according to claim 5, wherein the inorganic protective layer has an elemental composition ratio of oxygen and Group 13 element (oxygen/Group 13 element) of 1.1 or more and 1.5 or less. A conductive substrate;
a photosensitive layer provided on the conductive substrate;
an inorganic protective layer provided on the photosensitive layer;
having
the photosensitive layer contains a lubricating oil in an amount of 0.0001% by mass or more relative to the total solid content of the photosensitive layer, and the content of silica particles in the total solid content of the photosensitive layer is 0% by mass or 20% by mass or less. An electrophotographic photoreceptor according to any one of claims 1 to 7,
A process cartridge that can be attached to and removed from an image forming apparatus. The electrophotographic photoreceptor according to any one of claims 1 to 7,
a charging means for charging the surface of the electrophotographic photoreceptor;
an electrostatic latent image forming means for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;
a developing unit for developing an electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image;
a transfer means for transferring the toner image onto a surface of a recording medium;
An image forming apparatus comprising: