JP2002258506A - Electrophotographic sensitive body, electrophotographic method, electrophotographic device and process cartridge for electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive body by which a high quality image is stably obtained even for higher durability, higher sensitivity and repeated use and an electrophotographic method, an electrophotographic device and a process cartridge for electrophotography to eliminate necessity for replacing the photosensitive body, to enable high speed printing and by which the high quality image is stably obtained even in the repeated use. SOLUTION: In this electrophotographic sensitive body constituted by providing a single layer photosensitive layer or laminated structure of an electric charge generation layer and an electric charge transportation layer on a conductive base, when one or a plurality of kinds of fillers are contained in the most front surface layer of the electrophotographic sensitive body and relation between quantum efficiency ηof the photosensitive body and field intensity E regarding the photosensitive body is expressed by a formula (I), it is characterized that b is <=0.5 and film thickness of the single layer photosensitive layer or the electric charge transportation layer is <=25 μm. η=a×E<b> (I) (η denotes the quantum efficiency of the photosensitive body, (a) denotes a coefficient and E denotes the field intensity).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member having high sensitivity, high resolution, and high durability. In addition, the present invention relates to an electrophotographic method, an electrophotographic apparatus, and an electrophotographic process cartridge using the photoconductor.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable development of an information processing system using an electrophotographic system. Particularly, laser printers and digital copiers that convert information into digital signals and record information by light have remarkably improved in print quality and reliability. Further, they have been applied to laser printers or digital copying machines capable of full-color printing by fusing with high-speed technology. From such a background, high image quality, high durability, and high sensitivity have become particularly important as functions of the photoreceptor required.

As the photoreceptor used in these electrophotographic laser printers, digital copiers and the like, those using an organic photosensitive material have been widely applied for reasons such as cost, productivity and non-pollutability. Have been. Organic electrophotographic photoreceptors include a photoconductive resin represented by polyvinyl carbazole (PVK) and PVK-TNF (2, 4, 7).
-Trinitrofluorenone), a pigment-dispersed type represented by a phthalocyanine-binder, a function-separated type photoreceptor using a combination of a charge generating substance and a charge transporting substance, and the like. In particular, the function-separated type is the current mainstream.

The mechanism of the formation of an electrostatic latent image in a function-separated type photoreceptor is such that, when the photoreceptor is charged and irradiated with light, the light passes through the charge transport layer and is absorbed by the charge generation material in the charge generation layer. Generate electric charge. The generated charge is injected into the charge transport layer at the interface between the charge generation layer and the charge transport layer, and further moves in the charge transport layer by an electric field to neutralize the surface charge of the photoreceptor to form an electrostatic latent image. To form. In a function-separated type photoconductor,
A charge transport material that absorbs mainly in the ultraviolet and a charge generating material that absorbs mainly in the visible region are used in combination, but characteristics such as quantum efficiency and sensitivity are determined by the charge generation efficiency and charge injection efficiency. Therefore, it largely depends on the materials used and their combinations.

[0005] In recent years, the sensitivity and responsiveness of the photoconductor have been required with the speeding up of the electrophotographic apparatus, and the diameter of the photoconductor has been reduced with the downsizing of the apparatus, and the durability of the photoconductor has been required to be high. There is a tendency. Patent No. 28
Japanese Patent No. 38891 focuses on the electric field dependence of the quantum efficiency of the photoconductor, and the electric field dependence of the quantum efficiency is sufficiently small such that the value corresponding to b in the following formula (I) of the present invention is 0.5 or less. There is disclosed a photoreceptor having a specific charge generation layer having a property and having a charge transport layer having a thickness of 25 μm to 60 μm to achieve both improved durability and high sensitivity. η = a × E ^b (I) (where, η is the quantum efficiency of the photoconductor, a is a constant, and E is the electric field intensity.)

In general, a low-molecular charge transport material used for a charge transport layer has no film-forming property by itself, and is usually used by being dispersed and mixed in an inert polymer. The charge transport layer composed of a substance and an inert polymer generally has low hardness, and in the Carlson process, there is a problem that film scraping due to repeated use is large. As the film of the photosensitive layer is abraded, there is a strong tendency that a reduction in the charging potential of the photosensitive member, a deterioration in photosensitivity, background fouling due to scratches on the surface of the photosensitive member, a decrease in image density, or an image defect are promoted. Therefore, increasing the thickness of the charge transport layer is preferable in terms of increasing durability against film scraping due to repeated use.

In the case where a charge-generating substance having a small electric field dependence such that b is 0.5 or less in the above formula is used, the journal of the Electrographic Society of Japan, vol. 31, No. 2, 149 (199)
As described in 2), it is known that the sensitivity increases as the thickness of the charge transport layer increases. Accordingly, Japanese Patent No. 2838891 uses such a charge-generating substance having a small electric field dependence, that is, a charge-generating substance having a large sensitivity-dependent film thickness dependence, and further reduces the thickness of the charge transport layer by two.
This shows that the increase in the sensitivity to 5 μm or more has realized high sensitivity.

However, when a charge-generating substance having a large dependence of sensitivity on film thickness as described above is used, the sensitivity is naturally lowered as the film thickness of the charge-transporting layer is reduced due to film scraping due to repeated use. Will be. In Japanese Patent No. 2838891, the charge transport layer has a thickness of 2
It is considered that increasing the thickness to 5 μm to 60 μm not only has the effect of increasing durability but also increasing the sensitivity, but also has an effect of slightly suppressing the sensitivity decrease due to the decrease in the film thickness. The effect is not negligible as long as the film thickness fluctuates due to chipping.

On the other hand, in a recent electrophotographic process, a so-called digital electrophotographic system in which an electrostatic latent image is written on a photoreceptor by a light pulse such as an LD or an LED, has high image quality, high speed, It has become mainstream in terms of the development potential of digital networks,
As described above, the demand for higher image quality, higher speed, and higher durability has been increasing year by year due to the widespread use of printers and copiers using these methods, and also full color printers. Against this background, the tendency to shift to LDs or LEDs with a smaller beam diameter and higher output has increased, and by using them, finer dots can be written on the photoreceptor, resulting in an image. That is, the image quality can be remarkably improved.

However, it is necessary to reduce the thickness of the charge transport layer in order to improve the image quality. It is true that increasing the film thickness is effective for increasing the sensitivity or durability, but the charge injected into the charge transport layer reaches the surface and neutralizes the surface charge. Since the rectilinearity of the charge transfer is reduced to cause bleeding of the image, it is a fatal problem for high image quality, and there is no merit in reducing the beam diameter. In addition, as the thickness of the charge transport layer increases, the effect thereof becomes conspicuous, causing image deterioration. Furthermore, when the thickness of the photosensitive layer varies greatly with time, the stability of the image quality with time is affected, and it is important to suppress the abrasion resistance in order to realize high image quality.

Further, as the output of the LD increases, the sensitivity of the photoreceptor and the high-speed response become more important.
In other words, when the light amount becomes considerably large, the charge transport process becomes rate-determining, and it is considered that a state in which generated charges cannot be sufficiently transported to the surface is reached. Appears prominently. Therefore, in order to further increase the speed or reduce the size of the electrophotographic device, not only the sensitivity of the photoreceptor is high, but also the high-speed response corresponding to the photoreceptor is provided, and the thickness of the charge transport layer is reduced. A smaller design is required.

As described above, in the conventional method, in order to increase the sensitivity of the photoreceptor, a photoreceptor having a small dependence of the quantum efficiency on the electric field intensity, such as b being 0.5 or less in the above equation, is used. However, these photoreceptors have a large sensitivity dependency on the thickness of the photosensitive layer, so that the sensitivity of the photoreceptor changes over time due to film shaving during repeated use.
In addition, the image density and the image quality change with time due to this, and the stability of the image quality is greatly reduced. Also,
As the film thickness of the photosensitive layer becomes thinner due to abrasion, the electric field intensity increases, and image defects such as background contamination are significantly generated,
When the thickness of the photosensitive layer is increased in consideration of abrasion, the straightness of the charge is reduced, and the resolution is significantly reduced. Furthermore, in an electrophotographic apparatus employing a digital system,
In the future, as speeding up and downsizing are further demanded, higher durability, higher sensitivity and higher image quality of the photoreceptor are more important. Conventionally, there is no means for solving these problems at the same time, and a photoreceptor that achieves high image quality while maintaining high sensitivity and high durability, and achieves improvement in sensitivity and stability over time of image quality has been eagerly desired. Was.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photoreceptor capable of stably obtaining high-quality images even with high durability, high sensitivity and repeated use. Also,
An electrophotographic method, an electrophotographic apparatus, and an electrophotographic process cartridge capable of performing high-speed printing without requiring replacement of the photoconductor by using those photoconductors, and stably obtaining high-quality images even when repeatedly used. Is to provide.

[0014]

As a result of intensive studies, the present inventors have satisfied the following constitutional requirements, have high durability, and stably produce high-quality images against repeated use. The present invention provides an electrophotographic method, an electrophotographic apparatus, and an electrophotographic process cartridge capable of providing a photoreceptor obtained and obtaining a high-quality image stably and at high speed even in repeated use. Was completed.

In order to increase the sensitivity of the photoreceptor,
It is effective to use a charge generating substance having a small electric field dependence of quantum efficiency such that b is 0.5 or less in the following formula (I). As a result, a photoreceptor having a light attenuation curve with a sharp edge even at a low electric field can be obtained, and disadvantages such as a decrease in image density and a loss of color balance can be solved. Further, it is possible to cope with an increase in the speed of the apparatus.
The dependence of the quantum efficiency on the electric field largely depends on the characteristics of the charge generating substance used, and it is necessary to select an optimal charge generating substance. η = a × E ^b (I) (where, η is the quantum efficiency of the photoconductor, a is a constant, and E is the electric field intensity.)

In order to realize high durability (improvement of wear resistance) of the photoconductor, it is effective to include a filler in the outermost surface layer of the photoconductor. By including a filler, remarkable improvement in abrasion resistance can be realized.However, depending on the type of filler used, sufficient durability cannot be obtained, or the electrostatic characteristics are deteriorated or an abnormal image is caused. It is necessary to optimize the particle size and the like.

In order to realize a high-quality photoreceptor, it is effective to reduce the thickness of the charge transport layer. By realizing the improvement of the abrasion resistance described above, the charge transport layer can be satisfied with a small film thickness of 25 μm or less, so that even small dots do not bleed, and more faithful writing can be performed. Gives a great advantage to. In addition, this has a further synergistic effect on higher image quality by reducing the beam diameter of an LD or the like. In addition, since the outermost layer has a filler, the thickness of the charge transport layer hardly changes even after repeated use, so that there is little change in sensitivity and image density over time, and a high-quality image can be stably obtained. Become.

That is, according to the present invention, the following (1)
(39) are provided. (1) In an electrophotographic photosensitive member having a single-layer photosensitive layer containing at least a charge-generating substance and a charge-transporting substance on a conductive support, one or more kinds of fillers are provided on the outermost surface layer of the electrophotographic photosensitive member. And the quantum efficiency η of the photoreceptor and the electric field intensity E applied to the photoreceptor
Wherein, when the relationship is represented by the following formula (I), b is 0.5 or less, and the thickness of the photosensitive layer is 25 μm or less. η = a × E ^b (I) (where, η is the quantum efficiency of the photoconductor, a is a constant, and E is the electric field intensity.)

(2) An electrophotographic photoreceptor comprising a laminated structure of a charge generating layer containing at least a charge generating substance and a charge transporting layer containing a charge transporting substance on a conductive support. When one or more kinds of fillers are contained in the outermost surface layer, and the relationship between the quantum efficiency η of the photoreceptor and the electric field intensity E applied to the photoreceptor is expressed by the following formula (I), b is 0.5 or less. And the charge transport layer has a thickness of 25 μm or less. η = a × E ^b (I) (where, η is the quantum efficiency of the photoconductor, a is a constant, and E is the electric field intensity.)

(3) The electrophotographic photosensitive member according to (1) or (2), wherein a protective layer is formed as an outermost surface layer on the single-layer photosensitive layer or the charge transport layer.

(4) The film thickness of the single-layer photosensitive layer or the charge transport layer is 20 μm or less.
The electrophotographic photosensitive member according to any one of (3).

(5) The charge generating substance is an azo pigment or a phthalocyanine pigment.
The electrophotographic photosensitive member according to any one of (4).

(6) The electrophotographic photoreceptor according to (5), wherein the azo pigment is an azo pigment represented by the following formula (II).

[0024]

Embedded image (In the formula (II), Cp ₁ and Cp ₂ represent a coupler residue.
R ₂₀₁ and R ₂₀₂ each represent any of a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, and a cyano group;
They may be the same or different. Cp ₁ and Cp ₂ are represented by the following formula (III),

[0025]

Embedded image In the formula (III), R ₂₀₃ represents any one of a hydrogen atom, an alkyl group and an aryl group, and R ₂₀₄ , R ₂₀₅ , R ₂₀₆ , R ₂₀₇ ,
R ₂₀₈ represents any of a hydrogen atom, a nitro group, a cyano group, a halogen atom, a trifluoromethyl group, an alkyl group, an alkoxy group, a dialkylamino group, and a hydroxyl group, and Z is a substituted or unsubstituted aromatic carbocyclic ring Alternatively, it represents an atom group necessary for constituting a substituted or unsubstituted aromatic heterocyclic ring. )

(7) The electrophotographic photosensitive member according to (6), wherein Cp ₁ and Cp ₂ of the azo pigment are different from each other.

(8) The electrophotographic photosensitive member according to (5), wherein the phthalocyanine pigment is titanyl phthalocyanine.

(9) The titanyl phthalocyanine is C
(8) a titanyl phthalocyanine having a maximum diffraction peak at least at 27.2 ° as a diffraction peak (± 0.2 °) at a Bragg angle of 2θ with respect to characteristic X-ray (wavelength 1.514 °) of uKα. The electrophotographic photosensitive member according to the above.

(10) The filler contained in the outermost surface layer of the photoreceptor is an inorganic material.
The electrophotographic photosensitive member according to any one of (9).

(11) The electrophotographic photosensitive member according to (10), wherein the inorganic material contains at least one kind of metal oxide.

(12) The electrophotographic photosensitive member according to (11), wherein the metal oxide is at least one selected from silica, alumina and titanium oxide.

(13) The electrophotographic photosensitive member according to any one of (10) to (12), wherein at least one of the inorganic materials has been subjected to a surface treatment with at least one surface treatment agent. .

(14) The electrophotographic photosensitive member according to (13), wherein the surface treating agent is at least a titanate coupling agent, a higher fatty acid or a metal salt of a higher fatty acid.

(15) The electrophotographic photosensitive member according to (13) or (14), wherein the surface treatment amount of the inorganic material subjected to the surface treatment is 2 to 30% by weight.

(16) The average primary particle size of the inorganic material is as follows:
It is characterized by being 0.01 μm to 0.8 μm (1
The electrophotographic photosensitive member according to any one of (0) to (15).

(17) The layer containing the filler contains a dispersant. (1) to (16)
The electrophotographic photosensitive member according to any one of the above.

(18) 10 to 400 (mg)
(17) characterized by having an acid value of (KOH / g).
The electrophotographic photosensitive member according to the above.

(19) The electrophotographic photosensitive member according to (17) or (18), wherein the dispersant is an organic compound containing at least one carboxyl group in the structure.

(20) The electrophotographic photosensitive member according to (19), wherein the organic compound having at least one carboxyl group in the structure is a polycarboxylic acid derivative.

(21) When the content of the dispersant is A, the acid value of the dispersant is B, and the content of the filler is C, the following relational expression is established between A, B and C. The electrophotographic photoreceptor according to any one of (17) to (20), wherein: 0.1 ≦ (A × B) / C ≦ 20

(22) The electrophotographic photosensitive member according to any one of (3) to (21), wherein the protective layer contains a charge transport material.

(23) The following relational expression is established between the ionization potential Ip of the charge transport material contained in the protective layer and that of the charge transport material contained in the single-layer photosensitive layer or the charge transport layer. The electrophotographic photosensitive member according to (22), which is characterized in that: Ip of charge transport material contained in protective layer ≦ Ip of charge transport material contained in single-layer photosensitive layer or charge transport layer

(24) The electrophotographic photosensitive member according to (22), wherein the charge transporting substance contained in the protective layer contains a polymer charge transporting substance.

(25) The polymer charge transporting material is a polycarbonate containing at least a triarylamine structure in a main chain and / or a side chain.
4) The electrophotographic photosensitive member according to the above.

(26) In the electrophotographic method wherein at least charging, image exposure, development and transfer are repeatedly performed on the electrophotographic photosensitive member, the electrophotographic photosensitive member may be any one of (1) to (25). An electrophotographic method characterized by being a photographic photoreceptor.

(27) At least charging, image exposure, development, and transfer are repeatedly performed on the electrophotographic photosensitive member, and at the time of image exposure, an electrostatic latent image is written on the photosensitive member by an LD or LED. A digital electrophotographic method, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of (1) to (25).

(28) An electrophotographic apparatus comprising at least a charging means, an image exposing means, a developing means, a transferring means and an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is any one of (1) to (25) An electrophotographic apparatus, wherein the electrophotographic photoreceptor is described.

(29) An electrophotographic apparatus comprising at least a charging unit, an image exposing unit, a developing unit, a transferring unit and an electrophotographic photosensitive member, wherein the image exposing unit is formed by using an LD or LED. In a digital electrophotographic apparatus on which an electrostatic latent image is written, the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of (1) to (25). Electrophotographic equipment.

(30) The electrophotographic apparatus according to (28) or (29), wherein a roller-shaped charging member is used as the charging means in the electrophotographic apparatus.

(31) The electrophotographic apparatus according to (30), wherein in the electrophotographic apparatus using the roller-shaped charging member as charging means, the charging member and the photosensitive member are not in contact in the image forming area. Photo equipment.

(32) The electrophotographic apparatus using the roller-shaped charging member as a charging means, wherein an alternating current component is superimposed on a direct current component to charge the photosensitive member (30) or (31). Electrophotographic equipment.

(33) The electrophotographic apparatus according to (28) or (29), wherein said electrophotographic apparatus has means for adhering a lubricating substance to the surface of said photoreceptor.

(34) In the electrophotographic apparatus, the developer used for developing the latent image on the photosensitive member is developed by using a developer containing at least one lubricating substance. The electrophotographic apparatus according to (33), wherein the lubricating substance is attached to a body surface.

(35) In the electrophotographic apparatus, the lubricating substance is attached to the surface of the photoreceptor by bringing the lubricating substance into contact with the surface of the photoreceptor from the outside. apparatus.

(36) The electrophotographic apparatus according to any one of (33) to (35), wherein in the electrophotographic apparatus, at least one lubricating substance is zinc stearate.

(37) The electrophotographic apparatus according to any one of (33) to (35), wherein in the electrophotographic apparatus, at least one kind of lubricating substance is a fluorine compound.

(38) A process cartridge for an electrophotographic apparatus comprising at least an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of (1) to (25). A process cartridge for an electrophotographic apparatus.

(39) The method according to (3), wherein the device is used in the electrophotographic apparatus according to any one of (28) to (37).
8) The process cartridge for an electrophotographic apparatus according to the above.

Hereinafter, the electrophotographic photosensitive member used in the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating an electrophotographic photoreceptor of the present invention, in which a single-layer photosensitive layer 3 containing a charge generating substance and a charge transporting substance as main components on a conductive support 31.
3 are provided. In this case, at least the surface of the single-layer photosensitive layer 33 contains a filler, and the thickness of the single-layer photosensitive layer 33 is at least 25 μm or less.

FIG. 2 shows a configuration in which a charge generation layer 35 mainly composed of a charge generation substance and a charge transport layer 37 mainly composed of a charge transport substance are laminated on a conductive support 31. ing. In this case, at least the surface of the charge transport layer 37 contains a filler, and the thickness of the charge transport layer 37 is at least 25 μm or less.

FIG. 3 shows that a single-layer photosensitive layer 33 mainly composed of a charge-generating substance and a charge-transporting substance is provided on a conductive support 31, and a protective layer 39 is further provided on the surface of the single-layer photosensitive layer. I have. In this case, the protective layer 39 contains a filler, and the film thickness of the single-layer photosensitive layer 33 is at least 25 μm or less.

FIG. 4 shows a configuration in which a charge generation layer 35 mainly composed of a charge generation substance and a charge transport layer 37 mainly composed of a charge transport substance are laminated on a conductive support 31. Further, a protective layer 39 is provided on the charge transport layer 37. In this case, the protective layer 39 contains a filler, and the thickness of the charge transport layer 37 is at least 25 μm or less.

In any case, it is necessary that the dependence of the quantum efficiency of the photoreceptor on the electric field strength satisfies the above formula (I).

The conductive support 31 may have a volume resistance of 10
Those exhibiting conductivity of ¹⁰ Ωcm or less, for example, aluminum, nickel, chromium, nichrome, copper, gold, silver, metals such as platinum, tin oxide, metal oxides such as indium oxide, by evaporation or sputtering, Film or cylindrical plastic or paper coated or plates made of aluminum, aluminum alloy, nickel, stainless steel, etc., and extruded, drawn, etc., made into a tube, then cut, super finished, polished, etc. The surface-treated tube can be used. Further, an endless nickel belt and an endless stainless belt disclosed in JP-A-52-36016 can also be used as the conductive support 31.

In addition, those obtained by dispersing a conductive powder in a suitable binder resin on the above-mentioned support and applying the same can also be used as the conductive support 31 of the present invention. This conductive powder includes carbon black, acetylene black, aluminum, nickel, iron, nichrome,
Metal powder such as copper, zinc and silver, or conductive tin oxide, I
Metal oxide powders such as TO can be used. The binder resins used simultaneously include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, and vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene,
Thermoplasticity such as poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin,
Thermosetting resins and photocurable resins are exemplified. Such a conductive layer can be provided by dispersing the conductive powder and the binder resin in an appropriate solvent, for example, tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene, or the like, and applying the dispersion.

Further, heat shrinkage of a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark), and the like containing the conductive powder on a suitable cylindrical substrate. Also those that have a conductive layer provided by a tube,
It can be used favorably as the conductive support 31 of the present invention.

Next, the photosensitive layer will be described. The photosensitive layer may be a single layer or a laminate, but for convenience of explanation, the case where the photosensitive layer is composed of the charge generation layer 35 and the charge transport layer 37 will be described first.

The charge generation layer 35 is a layer containing a charge generation substance as a main component. For the charge generation layer 35, known charge generation substances can be used. Representative examples thereof include monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments, and quinone condensed polycyclic pigments. Compounds, squaric acid-based dyes, other phthalocyanine-based pigments, naphthalocyanine-based pigments, azurenium salt-based dyes, and the like can be used. These charge generating substances may be used alone or in combination of two or more.

As described above, it is not an exaggeration to say that the electric field strength dependence of the quantum efficiency of the photoreceptor is almost always determined by the charge generating substance. Accordingly, from the above-mentioned charge generating substances, those whose quantum efficiency depends on the electric field intensity satisfy the above-mentioned formula (I) are selected. In particular, the above (II)
It preferably contains an azo pigment represented by the formula or titanyl phthalocyanine. The titanyl phthalocyanine has a diffraction peak (± 0.2 °) at a Bragg angle 2θ of at least 27 with respect to the characteristic X-ray (wavelength 1.514 °) of CuKα. Titanyl phthalocyanine having a maximum diffraction peak at 0.2 ° is preferred. These charge generating substances are very effective and useful for increasing the sensitivity of the photoreceptor.

In the formula (II), R ₂₀₁ and R ₂₀₂ include a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group and a cyano group. The halogen atom is fluorine, chlorine, bromine or iodine, the alkyl group is an alkyl group having 1 to 4 carbon atoms such as a methyl group or an ethyl group, and the alkoxy group is 1 carbon atom such as a methoxy group or an ethoxy group. To 4 alkoxy groups. In addition, the (II
I) In the formula, the alkyl group of R ₂₀₃ includes a methyl group and an ethyl group, and the aryl group includes a phenyl group and the like _. The halogen atom of R ₂₀₄ , R ₂₀₅ , R ₂₀₆ , R ₂₀₇ and R ₂₀₈ is exemplified. As fluorine, chlorine, bromine, iodine, etc., as an alkyl group, a methyl group, an ethyl group, etc., as an alkoxy group, a methoxy group, an ethoxy group, etc., and as a dialkylamino group, a dimethylamino group, a diethylamino group. And the like. Cp ₁ and Cp ₂ may be different or the same.

The charge generation layer 35 is formed by dispersing a charge generation material together with a binder resin in an appropriate solvent using a ball mill, an attritor, a sand mill, ultrasonic waves, or the like, if necessary.
This is formed by applying this on a conductive support and drying it.

If necessary, the binder resin used for the charge generation layer 35 includes polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, and the like. Poly-N-vinyl carbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl And pyrrolidone.
The amount of the binder resin is 0 to 100 parts by weight of the charge generating substance.
500 parts by weight, preferably 10 to 300 parts by weight, is suitable.

The solvents used herein include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane,
Toluene, xylene, ligroin and the like can be mentioned. Particularly, ketone solvents, ester solvents and ether solvents are preferably used.

The charge generation layer 35 contains a charge generation substance, a solvent and a binder resin as main components, and contains any additives such as a sensitizer, a dispersant, a surfactant and a silicone oil. It may be.

As a method of applying the coating solution, a dip coating method, a spray coat, a beat coat, a nozzle coat, a spinner coat, a ring coat and the like can be used.

The charge generation layer 35 has a thickness of 0.01 to 5 μm.
m is appropriate, and preferably 0.1 to 2 μm.

The charge transporting layer 37 can be formed by dissolving or dispersing a charge transporting substance and a binder resin in an appropriate solvent, applying the solution on the charge generating layer, and drying. Also,
If necessary, one or more plasticizers, leveling agents, antioxidants and the like can be added.

The charge transport material includes a hole transport material and an electron transport material. Examples of the electron transporting material include chloranil, bromanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone,
2,4,8-trinitrothioxanthone, 2,6,8-
Examples thereof include electron accepting substances such as trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, and benzoquinone derivatives.

Examples of the hole transport material include poly-N-vinylcarbazole and its derivatives, poly-γ-carbazolylethylglutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, polysilane, Oxazole derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives,
α-phenylstilbene derivative, benzidine derivative, diarylmethane derivative, triarylmethane derivative, 9
-Known materials such as styrylanthracene derivative, pyrazoline derivative, divinylbenzene derivative, hydrazone derivative, indene derivative, butadiene derivative, pyrene derivative, bisstilbene derivative, enamine derivative and the like. These charge transport materials are used alone or in combination of two or more.

Examples of the binder resin include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, and polystyrene. Vinyl acetate, polyvinylidene chloride, polyalate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane Thermoplastic or thermosetting resins such as resin, phenolic resin, and alkyd resin are exemplified.

The amount of the charge transporting substance is 20 to 300 parts by weight, preferably 40 to 150 parts by weight, per 100 parts by weight of the binder resin.
Parts by weight are appropriate. The thickness of the charge transport layer is 25 μm or less, and more preferably 20 μm or less, from the viewpoint of resolution and response. When the thickness of the charge transport layer is more than 25 μm, the straightness of charge transfer from the charge generation layer to the charge transport layer until the charge injected to the charge transport layer reaches the surface of the photoreceptor is sharply reduced, and the image is blurred. Image quality will be degraded. This effect is smaller when the thickness of the charge transport layer is smaller, which is advantageous for improving image quality. However, when the thickness of the charge transport layer is extremely thin, the charging ability of the photoreceptor is reduced, and the charge transport layer is liable to be affected by the electric field intensity. The lower limit varies depending on the system used, but is preferably 5 μm or more, more preferably 10 μm or more.

The solvents used here are tetrahydrofuran, dioxane, toluene, dichloromethane,
Monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used.

When the charge transport layer is to be the outermost surface layer of the photoreceptor, a filler material is added to at least the surface of the charge transport layer for the purpose of improving abrasion resistance. Filler materials are mainly classified into organic fillers and inorganic fillers, and organic filler materials include fluororesin powder such as polytetrafluoroethylene, silicone resin powder, a-carbon powder, etc. As the conductive filler material, metal powders such as copper, tin, aluminum and indium, silica, tin oxide, zinc oxide, titanium oxide, alumina, indium oxide, antimony oxide, bismuth oxide, calcium oxide, tin oxide doped with antimony, Examples include metal oxides such as indium oxide doped with tin, metal fluorides such as tin fluoride, calcium fluoride, and aluminum fluoride, and inorganic materials such as potassium titanate and boron nitride. Among these fillers, it is advantageous to use an inorganic material from the viewpoint of the hardness of the filler for improving wear resistance. Among inorganic materials, metal oxides are preferable, and silica, titanium oxide, and alumina have high effects on wear resistance and can be used effectively. Among them, alumina is effective because of its high light transmittance and little influence of image blur, and α-alumina can be used particularly effectively. These filler materials are used alone or in combination of two or more.

Further, at least one of these fillers may be used.
Surface treatment with a surface treatment agent
Is preferable from the viewpoint of filler dispersibility. Fira
Decrease in the dispersibility of the coating not only increases the residual potential, but also
Deterioration of transparency, occurrence of coating defects, and low abrasion resistance
It also causes lowering, preventing high durability or high image quality.
Could develop into a big problem. Surface treatment agent and
Use all conventionally used surface treatment agents.
Surface that can maintain filler insulation
Treatment agents are preferred. For example, titanate coupling
Agent, aluminum coupling agent, zirconalumina
G-based coupling agents, higher fatty acids, higher fatty acid metal salts
Or a mixture of these with a silane coupling agent.
Al, Al _TwoO_Three, TiO_Two, ZrO_Two, Silicone,
Aluminum arsenate, etc., or their mixed treatment
It is more preferable from the viewpoint of filler dispersibility and image blur.
Treatment with a silane coupling agent reduces the effects of image blur.
Stronger, but the above surface treatment agent and silane coupling agent
If the effect can be suppressed by performing a mixing process with
There is a case. Regarding the amount of surface treatment,
Depending on the uniform primary particle size, 2-30 wt% is suitable
And 5 to 20 wt% is more preferable. Surface treatment amount
If it is less than the range, the effect of dispersing the filler cannot be obtained,
On the other hand, if it is too large, a remarkable increase in the residual potential is caused.

The presence of these fillers may increase the effect of a rise in residual potential. In order to suppress the rise in the residual potential, it is necessary to add a dispersant to improve the dispersibility of the filler. further,
When the dispersant has an acid value of 10 to 400 (mgKOH / g), the effect of reducing the residual potential may be increased.
The acid value is defined as the number of milligrams of potassium hydroxide required to neutralize free fatty acids contained in 1 g. As these dispersants, organic compounds containing at least a carboxyl group in the structure are preferable, and polycarboxylic acid derivatives are more preferable. Among these, all organic compounds containing carboxylic acids or derivatives thereof, such as polyester resins, acrylic resins, copolymers using acrylic acid or methacrylic acid, and styrene-acrylic copolymers, can be used. In particular, in order to disperse the inorganic filler in the binder resin, the addition of the dispersant is very effective. The dispersant can make both the filler and the binder resin having no direct affinity have an affinity, and the filler dispersibility is significantly improved.

The acid value of the dispersant is 10 to 400 mg
KOH / g is preferred, but more preferably 30-200.
mg KOH / g. If the acid value is unnecessarily high, the resistance will be too low and the effect of image blur will increase. If the acid value is too low, the amount of addition must be increased, and the effect of reducing the residual potential will be insufficient.

When the content of the dispersant is A, the acid value of the dispersant is B, and the content of the filler is C,
By satisfying the following relational expression between B and C, it is possible to exert their effects sufficiently, but it is preferable to set them to the necessary minimum amount. 0.1 ≦ (A × B) / C ≦ 20 When the content of the dispersant is too small, the dispersion of the filler may be caused or the residual potential may be significantly increased. If the amount is too large, the effect of image blur may increase.

These filler materials can be dispersed together with a charge transporting substance, a binder resin, a solvent and the like by using an appropriate disperser. The average primary particle size of the filler is
It is preferably from 0.01 to 0.8 μm from the viewpoint of the transmittance and abrasion resistance of the charge transport layer.

It is also possible to include these fillers in the entire charge transport layer. However, since the potential of the exposed portion may increase, the outermost surface of the charge transport layer has the highest filler concentration, It is preferable to provide a filler concentration gradient so as to lower the body side, or to form a structure in which the charge transport layer is formed of a plurality of layers so that the filler concentration is gradually increased from the support side toward the surface side.

For the charge transport layer, a high molecular charge transport material having both a function as a charge transport material and a function as a binder resin is preferably used. The charge transport layer composed of these polymeric charge transport materials has excellent abrasion resistance. As the polymer charge transport material, known materials can be used. In particular, a triarylamine structure having a main chain and / or
Alternatively, a polycarbonate contained in a side chain is preferably used.
Among them, polymer charge transport materials represented by the formulas (IV) to (XIII) are preferably used. These are illustrated below and specific examples are shown.

[0091]

Embedded image (IV) In the formula, R ₁ , R ₂ and R ₃ each independently represent a substituted or unsubstituted alkyl group or a halogen atom, R ₄ represents a hydrogen atom or a substituted or unsubstituted alkyl group,
R ₅ and R ₆ represent a substituted or unsubstituted aryl group.
o, p, and q each independently represent an integer of 0 to 4, k, j
Represents the composition, 0.1 ≦ k ≦ 1, 0 ≦ j ≦ 0.9, and n represents the number of repeating units and is an integer of 5 to 5,000. X represents an aliphatic divalent group, a cycloaliphatic divalent group, or a divalent group represented by the following general formula.

[0092]

Embedded image In the formula, R ₁₀₁ and R ₁₀₂ each independently represent a substituted or unsubstituted alkyl group, aryl group, or halogen atom.
l and m are integers from 0 to 4, Y is a single bond, and has 1 to 1 carbon atoms.
2 linear, branched or cyclic alkylene group, -O
-, - S -, - SO -, - SO 2 -, - CO -, - CO
—O—Z—O—CO— (wherein, Z represents an aliphatic divalent group) or

[0093]

Embedded image (In the formula, a represents an integer of 1 to 20, b represents an integer of 1 to 2000, R ₁₀₃ and R ₁₀₄ represent a substituted or unsubstituted alkyl group or an aryl group, and may be the same or different.) . Here, _R101 and _R102 may be the same or different.

[0094]

Embedded image (V) In the formula, R ₇ and R ₈ represent a substituted or unsubstituted aryl group, and Ar ₁ , Ar ₂ and Ar ₃ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (IV).

[0095]

Embedded image (VI) In the formula, R ₉ and R ₁₀ represent a substituted or unsubstituted aryl group, and Ar ₄ , Ar ₅ , and Ar ₆ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (IV).

[0096]

Embedded image(VII) wherein R₁₁, R₁₂Is a substituted or unsubstituted ant
Is a group represented by Ar₇, Ar ₈, Ar₉Are the same or different ants
Represents a len group. X, k, j and n are in the case of the formula (IV)
Is the same as

[0097]

Embedded image (VIII) In the formula, R ₁₃ and R _{14 each} represent a substituted or unsubstituted aryl group; Ar ₁₀ , Ar ₁₁ , and Ar ₁₂ represent the same or different arylene groups; and X ₁ and X ₂ represent a substituted or unsubstituted ethylene group. Or a substituted or unsubstituted vinylene group. X,
k, j and n are the same as in the case of the formula (IV).

[0098]

Embedded image(IX) where R₁₅, R₁₆, R₁₇, R₁₈Is replaced or nothing
A substituted aryl group is represented by Ar₁₃, Ar₁₄, Ar₁₅, Ar₁₆
Represents the same or different arylene group, Y₁, Y_Two, Y _ThreeIs simple
A substituted or unsubstituted alkylene group,
Unsubstituted cycloalkylene group, substituted or unsubstituted
Alkylene ether group, oxygen atom, sulfur atom, vinylene group
And may be the same or different. X, k, j and
And n are the same as in the case of the formula (IV).

[0099]

Embedded image (X) In the formula, R ₁₉ and R ₂₀ represent a hydrogen atom or a substituted or unsubstituted aryl group, and R ₁₉ and R ₂₀ may form a ring. Ar ₁₇ , Ar ₁₈ and Ar ₁₉ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (IV).

[0100]

Embedded image (XI) In the formula, R ₂₁ represents a substituted or unsubstituted aryl group, and Ar ₂₀ , Ar ₂₁ , Ar ₂₂ , and Ar ₂₃ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (IV).

[0101]

Embedded image (XII) In the formula, R ₂₂ , R ₂₃ , R ₂₄ , and R ₂₅ represent a substituted or unsubstituted aryl group, and Ar ₂₄ , Ar ₂₅ , Ar ₂₆ , Ar
₂₇ and Ar ₂₈ represent the same or different arylene groups. X,
k, j and n are the same as in the case of the formula (IV).

[0102]

Embedded image (XIII) In the formula, R ₂₆ and R _{27 each} represent a substituted or unsubstituted aryl group, and Ar ₂₉ , Ar ₃₀ , and Ar ₃₁ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (IV).

The following are specific examples of the polymer charge transporting material represented by the general formula (IV).

[0104]

Embedded image

[0105]

Embedded image

[0106]

Embedded image

Specific examples of the polymer charge transporting material represented by the general formula (V) include the following.

[0108]

Embedded image

[0109]

Embedded image

[0110]

Embedded image

The following are specific examples of the polymer charge transporting material represented by the general formula (VI).

[0112]

Embedded image

[0113]

Embedded image

The following are specific examples of the polymer charge transporting material represented by the general formula (VII).

[0115]

Embedded image

[0116]

Embedded image

Specific examples of the polymer charge transporting material represented by the general formula (VIII) include the following.

[0118]

Embedded image

[0119]

Embedded image

[0120]

Embedded image

Specific examples of the polymer charge transporting material represented by the general formula (IX) include the following.

[0122]

Embedded image

[0123]

Embedded image

Specific examples of the polymer charge transporting material represented by the general formula (X) include the following.

[0125]

Embedded image

[0126]

Embedded image

The following are specific examples of the polymer charge transporting material represented by the general formula (XI).

[0128]

Embedded image

[0129]

Embedded image

[0130]

Embedded image

[0131]

Embedded image

The following are specific examples of the polymer charge transporting material represented by the general formula (XII).

[0133]

Embedded image

[0134]

Embedded image

Specific examples of the polymer charge transporting substance represented by the general formula (XIII) include the following.

[0136]

Embedded image

[0137]

Embedded image

[0138]

Embedded image

[0139]

Embedded image

Next, the case where the photosensitive layer has a single-layer structure 33 will be described. The single-layer photosensitive layer can be formed by dissolving or dispersing the above-described charge generating substance, charge transporting substance, and binder resin in an appropriate solvent, and applying and drying this.
If necessary, a plasticizer, a leveling agent, an antioxidant and the like can be added.

As the binder resin, in addition to the binder resin described above for the charge transport layer 37, the binder resin described for the charge generation layer 35 may be mixed and used. Of course, the above-mentioned polymer charge transport materials can also be used favorably. Binder resin 100
The amount of the charge generating substance is preferably 5 to 40 parts by weight, and the amount of the charge transporting substance is preferably 190 parts by weight or less, more preferably 50 to 150 parts by weight based on parts by weight. The single-layer photosensitive layer is formed by dispersing a charge generating substance and a binder resin together with a charge transport substance using a solvent such as tetrahydrofuran, dioxane, dichloroethane, or cyclohexane with a disperser or the like, by immersion coating, spray coating, or beading. It can be formed by coating with a coat or the like. The thickness of the single-layer photosensitive layer is 2
5 μm or less, and about 5 to 25 μm is appropriate.

In a structure in which the single-layer photosensitive layer is the outermost surface layer, at least the photosensitive layer surface must contain a filler in order to improve abrasion resistance. The filler and the dispersant are as described above for the charge transport layer. In this case, as in the case of the charge transport layer, the entire photosensitive layer may contain a filler.However, a gradient of the filler concentration is provided, or the photosensitive layer has a plurality of layers, and the filler concentration is sequentially changed. Doing so is an effective means.

In the photoreceptor of the present invention, an undercoat layer can be provided between the conductive support 31 and the single-layer or multi-layer photosensitive layer. The undercoat layer generally contains a resin as a main component. However, considering that the photosensitive layer is coated thereon with a solvent, these resins are resins having high solvent resistance to general organic solvents. desirable. Examples of such a resin include water-soluble resins such as polyvinyl alcohol, casein and sodium polyacrylate, alcohol-soluble resins such as copolymerized nylon and methoxymethylated nylon, polyurethane, melamine resin, phenolic resin, and alkyd.
Curable resins that form a three-dimensional network structure, such as melamine resins and epoxy resins, may be used. Further, a fine powder pigment of a metal oxide exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide or the like may be added to the undercoat layer in order to prevent moiré and reduce residual potential.

These undercoat layers may be of the above-mentioned single layer type or
Is formed using an appropriate solvent and coating method, such as a laminated photosensitive layer.
Can be achieved. Further, as an undercoat layer of the present invention,
Run coupling agent, titanium coupling agent, chrome
A coupling agent or the like can also be used. In addition,
In the light undercoat layer, Al_TwoO_ThreeProvided by anodic oxidation
And organic substances such as polyparaxylylene (parylene) and Si
O_Two, SnO_Two, TiO _Two, ITO, CeO_TwoAnd other inorganic substances
Those provided by a vacuum thin film manufacturing method can also be used favorably. This
In addition, known materials can be used. Undercoat layer
Is suitably from 0 to 5 μm.

In the photoreceptor of the present invention, the protective layer 39 may be provided on the single-layer photosensitive layer or the charge transport layer for the purpose of protection. Materials used for the protective layer 39 include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, aryl resin,
Phenolic resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallyl sulfone,
Polybutylene, polybutylene terephthalate, polycarbonate, polyether sulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin,
Resins such as polymethylbenthene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, polyarylate, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinylidene chloride, and epoxy resin.

In a structure in which the protective layer of the photoreceptor is the outermost layer, a filler material is added to the protective layer for the purpose of improving abrasion resistance. Filler materials are mainly classified into organic fillers and inorganic fillers, and organic filler materials include fluororesin powder such as polytetrafluoroethylene, silicone resin powder, a-carbon powder, etc. As the filler material,
Metal powders such as copper, tin, aluminum and indium, silica, tin oxide, zinc oxide, titanium oxide, alumina, indium oxide, antimony oxide, bismuth oxide, calcium oxide, tin oxide doped with antimony, and indium oxide doped with tin And metal fluorides such as tin fluoride, calcium fluoride, and aluminum fluoride; and inorganic materials such as potassium titanate and boron nitride.
Among these fillers, it is advantageous to use an inorganic material from the viewpoint of the hardness of the filler for improving wear resistance.
Among inorganic materials, metal oxides are preferable, and silica, titanium oxide, and alumina have high effects on wear resistance and can be used effectively. Among them, alumina is effective because of its high light transmittance and little influence of image blur.
-Alumina can be used particularly effectively. These filler materials are used alone or in combination of two or more.

Further, these fillers can be surface-treated with at least one kind of surface treating agent, and it is preferable to do so from the viewpoint of dispersibility of the filler. The decrease in the dispersibility of the filler not only increases the residual potential, but also causes a decrease in the transparency of the coating film, the occurrence of coating film defects, and a decrease in abrasion resistance, which hinders high durability or high image quality. It can evolve into a big problem. As the surface treatment agent, all the surface treatment agents conventionally used can be used, but a surface treatment agent capable of maintaining the insulating property of the filler is preferable. For example, titanate-based coupling agents, aluminum-based coupling agents, zircoaluminate-based coupling agents, higher fatty acids, higher fatty acid metal salts, or the like, or a mixture treatment thereof with a silane coupling agent, Al ₂ O ₃ , TiO _{2 2} , ZrO ₂ , silicone, aluminum stearate, and the like, or a mixture thereof is more preferable from the viewpoint of filler dispersibility and image blur.
Although the treatment with the silane coupling agent has a strong effect of image blur, the effect of mixing the surface treatment agent and the silane coupling agent may be suppressed in some cases. The surface treatment amount varies depending on the average primary particle size of the filler used, but 2 to 30% by weight is suitable, and 5 to 20% by weight is more preferable. If the amount of the surface treatment is smaller than this, the effect of dispersing the filler cannot be obtained, and if the amount is too large, the residual potential is significantly increased.

The inclusion of these fillers may increase the effect of a rise in residual potential. In order to suppress the rise in the residual potential, it is necessary to add a dispersant to improve the dispersibility of the filler. further,
When the dispersant has an acid value of 10 to 400 (mgKOH / g), the effect of reducing the residual potential may be increased.
The acid value is defined as the number of milligrams of potassium hydroxide required to neutralize free fatty acids contained in 1 g. As these dispersants, organic compounds containing at least a carboxyl group in the structure are preferable, and polycarboxylic acid compounds are more preferable. Among these, all organic compounds containing carboxylic acids or derivatives thereof, such as polyester resins, acrylic resins, copolymers using acrylic acid or methacrylic acid, and styrene-acrylic copolymers, can be used. In particular, in order to disperse the inorganic filler in the binder resin, the addition of the dispersant is very effective. The dispersant can make both the filler and the binder resin having no direct affinity have an affinity, and the filler dispersibility is significantly improved.

The acid value of the dispersant is 10 to 400 mg.
KOH / g is preferred, but more preferably 30-200.
mg KOH / g. If the acid value is unnecessarily high, the resistance will be too low and the effect of image blur will increase. If the acid value is too low, the amount of addition must be increased, and the effect of reducing the residual potential will be insufficient.

When the content of the dispersant is A, the acid value of the dispersant is B, and the content of the filler is C, A,
By satisfying the following relational expression between B and C, it is possible to exert their effects sufficiently, but it is preferable to set them to the necessary minimum amount. 0.1 ≦ (A × B) / C ≦ 20 When the content of the dispersant is too small, the dispersion of the filler may be caused or the residual potential may be significantly increased. If the amount is too large, the effect of image blur may increase.

These filler materials can be dispersed together with a charge transporting substance, a binder resin, an organic solvent, and the like by a conventional method such as a ball mill, an attritor, a sand mill, and ultrasonic waves. Among them, a ball mill which is less affected by contamination is most suitable. When a dispersant is contained, it is more preferable to add and mix the dispersant together with the filler and the organic solvent than before dispersion, from the viewpoint of filler dispersibility. On the other hand, it is preferable to add and mix the binder resin after dispersion from the viewpoint of filler dispersibility. Examples of the organic solvent used include tetrahydrofuran, dioxane, toluene, dichloromethane, cyclohexanone, methyl ethyl ketone, acetone, and the like.By using a mixture of two or more solvents, it is possible to achieve both filler dispersibility and coating quality. is there.

The addition of the low-molecular charge transport material or high-molecular charge transport material described in the charge transport layer 37 to the protective layer is an effective means for improving image quality and reducing residual potential. It is preferable to add and mix the charge transport material after the dispersion as in the case of the binder resin. Examples of the polymer charge transport material include polycarbonates having a triarylamine structure in a main chain and / or a side chain.

When the charge transporting substance is added to the protective layer, if the charge transporting substance Ip contained in the protective layer is larger than the charge transporting substance Ip contained in the photosensitive layer or the charge transporting layer, the charge generating layer may be charged. As the generated charges move to the charge transporting layer and further to the protective layer, the charge injecting property to the protective layer is reduced, thereby causing an increase in residual potential and deterioration in sensitivity. Therefore, it is preferable that the following relational expression be established between the ionization potential Ip of the charge transport material contained in the protective layer and the Ip of the charge transport layer contained in the single-layer photosensitive layer or the charge transport layer. Ip of charge transport material contained in protective layer ≦ Ip of charge transport material contained in single-layer photosensitive layer or charge transport layer

The average primary particle size of the filler is preferably from 0.01 to 0.8 μm, more preferably from 0.1 to 0.5 μm, from the viewpoint of the transmittance and abrasion resistance of the protective layer and the like.
When the primary particle size of the filler is too small, the cohesiveness of the filler is increased, the dispersibility is reduced, and the abrasion resistance tends to be reduced.When the primary particle size is too large, abnormal images and filming are likely to occur. Tend.

As a method for forming the protective layer, conventional methods such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, and ring coating can be used. Among them, the spray coating method is most preferable for enhancing the dispersibility of the filler in the film. The thickness of the protective layer is suitably about 0.5 to 10 μm, more preferably 2 to 10 μm.
６6 μm. A thinner protective layer, like the thickness of the photosensitive layer, is advantageous for higher image quality, but if it is too thin, the life of the photoconductor may be reduced. In that case, it is necessary to further increase the abrasion resistance, which may increase the influence of an abnormal image or filming. However, depending on the resistance of the filler contained in the protective layer, the formed electrostatic latent image is not necessarily the outermost surface of the photoconductor,
It may be formed at the interface between the photosensitive layer and the protective layer.

In the photoreceptor of the present invention, an intermediate layer may be provided between the single-layer photosensitive layer or the charge transport layer and the protective layer. The intermediate layer generally uses a binder resin as a main component. These resins include polyamide,
Examples thereof include alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the intermediate layer, a coating method generally used as described above is employed. The thickness of the intermediate layer is suitably about 0.05 to 2 μm.

In the present invention, a single-layer photosensitive layer, a charge generation layer, a charge transport layer, an undercoat layer, and a protective layer are provided for the purpose of improving environmental resistance, particularly, in order to prevent a decrease in sensitivity and an increase in residual potential. An antioxidant, a plasticizer, a lubricant, a UV absorber, a low-molecular charge transport substance and a leveling agent can be added to each layer such as an intermediate layer. Representative materials of these compounds are described below.

Examples of the antioxidant that can be added to each layer include, but are not limited to, the following. (A) Phenol compound 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, n-octadecyl -3- (4'-Hydroxy
-3 ', 5'-di-t-butylphenol), 2,2'-methylene-bis- (4-methyl-6-t-butylphenol),
2,2'-methylene-bis- (4-ethyl-6-t-butylphenol), 4,4'-thiobis- (3-methyl-6-t-butylphenol), 4,4'-butylidenebis -(3-methyl-6-t-butylphenol),
1,1,3-tris- (2-methyl-4-hydroxy-
5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-
4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate] methane, bis [3
3'-bis (4'-hydroxy-3'-tert-butylphenyl) butyric acid] glycol ester, tocopherols and the like.

(B) Paraphenylenediamines N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl- p-
Phenylenediamine, N, N'-di-isopropyl-p
-Phenylenediamine, N, N'-dimethyl-N, N'-
Di-t-butyl-p-phenylenediamine and the like.

(C) Hydroquinones 2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t
-Octyl-5-methylhydroquinone, 2- (2-octadecenyl) -5-methylhydroquinone and the like.

(D) Organic sulfur compounds Dilauryl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, ditetradecyl-3,3'-thiodipropionate and the like.

(E) Organic phosphorus compounds Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine and the like.

Examples of the plasticizer that can be added to each layer include, but are not limited to, the following. (A) Phosphate ester plasticizer triphenyl phosphate, tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, trichloroethyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, Triphenyl phosphate and the like.

(B) Phthalate ester plasticizers Dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dibutyl phthalate, diheptyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, di-n-phthalate Octyl, dinonyl phthalate, diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, ditridecyl phthalate, dicyclohexyl phthalate, butyl benzyl butyl, butyl lauryl phthalate, methyl oleyl phthalate, octyl decyl phthalate, dibutyl fumarate, Dioctyl fumarate and the like.

(C) Aromatic carboxylate plasticizers Trioctyl trimellitate, Tri-n trimellitate
-Octyl, octyl oxybenzoate and the like.

(D) Aliphatic dibasic ester plasticizer dibutyl adipate, di-n-hexyl adipate, di-2-ethylhexyl adipate, di-n-adipate
Octyl, n-octyl-n-octyl-n-decyl adipate, diisodecyl adipate, dicapryl adipate, di-2-ethylhexyl azelate, dimethyl sebacate,
Diethyl sebacate, dibutyl sebacate, di-n-octyl sebacate, di-2-ethylhexyl sebacate, di-2-ethoxyethyl sebacate, dioctyl succinate, diisodecyl succinate, dioctyl tetrahydrophthalate, dihydrotetrahydrophthalate -N-octyl and the like.

(E) Fatty acid ester derivatives butyl oleate, glycerin monooleate, methyl acetyl ricinoleate, pentaerythritol ester, dipentaerythritol hexaester,
Triacetin, tributyrin and the like.

(F) Oxyacid ester plasticizers Methyl acetyl ricinoleate, butyl acetyl ricinoleate, butyl phthalyl butyl glycolate, tributyl acetyl citrate and the like.

(G) Epoxy plasticizer Epoxidized soybean oil, epoxidized linseed oil, butyl epoxy stearate, decyl epoxy stearate, octyl epoxy stearate, benzyl epoxy stearate, dioctyl epoxy hexahydrophthalate, epoxy hexahydrophthalate Didecyl acid and the like.

(H) Dihydric alcohol ester plasticizers Diethylene glycol dibenzoate, triethylene glycol di-2-ethyl butyrate and the like.

(I) Chlorinated plasticizers Chlorinated paraffin, chlorinated diphenyl, chlorinated fatty acid methyl, methoxy chlorinated fatty acid methyl and the like.

(J) Polyester plasticizer Polypropylene adipate, polypropylene sebacate, polyester, acetylated polyester and the like.

(K) Sulfonic acid derivatives p-toluenesulfonamide, o-toluenesulfonamide, p-toluenesulfonethylamide, o-toluenesulfonethylamide, toluenesulfone-N-ethylamide, p-toluenesulfon-N-cyclohexyl Amides and the like.

(1) Citric acid derivatives Triethyl citrate, triethyl acetyl citrate, tributyl citrate, tributyl acetyl citrate, tri-2-ethylhexyl acetyl citrate, n-octyldecyl acetyl citrate and the like.

(M) Others terphenyl, partially hydrogenated terphenyl, camphor, 2
-Nitrodiphenyl, dinonylnaphthalene, methyl abietate and the like.

Examples of the lubricant that can be added to each layer include, but are not limited to, the following. (A) Hydrocarbon compounds Liquid paraffin, paraffin wax, microwax, low-polymerized polyethylene and the like.

(B) Fatty Acid Compounds Lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid and the like.

(C) Fatty acid amide compounds Stearyl amide, palmityl amide, olein amide, methylene bis-stearamide, ethylene bis-stearamide and the like.

(D) Ester compounds Lower alcohol esters of fatty acids, polyhydric alcohol esters of fatty acids, polyglycol esters of fatty acids and the like.

(E) Alcohol Compounds Cetyl alcohol, stearyl alcohol, ethylene glycol, polyethylene glycol, polyglycerol and the like.

(F) Metal soaps Lead stearate, cadmium stearate, barium stearate, calcium stearate, zinc stearate, magnesium stearate and the like.

(G) Natural waxes Carnauba wax, candelilla wax, beeswax, whale wax, Ibota wax, montan wax and the like.

(H) Others Silicone compounds, fluorine compounds and the like.

Examples of the ultraviolet absorber which can be added to each layer include the following, but are not limited thereto. (A) Benzophenone 2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,2 ′, 4-trihydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2,2′-dihydroxy-4- Methoxybenzophenone and the like.

(B) Salicylate type Phenyl salicylate, 2,4-di-t-butylphenyl 3,5-di-t-butyl 4-hydroxybenzoate and the like.

(C) Benzotriazole type (2'-hydroxyphenyl) benzotriazole,
(2'-hydroxy5'-methylphenyl) benzotriazole, (2'-hydroxy5'-methylphenyl) benzotriazole, (2'-hydroxy3'-tert-butyl5'-methylphenyl) 5-chlorobenzotriazole Such.

(D) Cyanoacrylates Ethyl-2-cyano-3,3-diphenyl acrylate, methyl 2-carbomethoxy 3 (paramethoxy) acrylate and the like.

(E) Quencher (metal complex salt) Nickel (2,2'thiobis (4-t-octyl) phenolate) normal butylamine, nickel dibutyl dithiocarbamate, nickel dibutyl dithiocarbamate, cobalt dicyclohexyl dithiophosphate and the like.

(F) HALS (hindered amine) bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1 -[2- [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionyloxy] ethyl] -4- [3- (3,5-
Di-tert-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpyridine,
8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione, 4-benzoyloxy-2,
2,6,6-tetramethylpiperidine and the like.

Next, the electrophotographic method and the electrophotographic apparatus of the present invention will be described in detail with reference to the drawings. FIG. 5 is a schematic diagram for explaining the electrophotographic method and the electrophotographic apparatus of the present invention, and the following examples also belong to the category of the present invention. In FIG. 5, a photoreceptor 1 is a photoreceptor of the present invention, and a photosensitive layer showing the electric field intensity dependence of the quantum efficiency represented by the above formula (I) is provided on a conductive support. It contains a filler. The photoconductor 1 has a drum shape, but may have a sheet shape or an endless belt shape. The charging charger 3, the pre-transfer charger 7, the transfer charger 10, the separation charger 11, and the pre-cleaning charger 13 include a corotron, a scorotron, a solid state charger (solid state charger),
A charging roller, a charging brush, a transfer roller, and the like are used, and all known means can be used.

The charging member is generally a non-contact charging by a corona charging method or a contact charging by a roller or brush-shaped charging member, and can be effectively used in the present invention. In particular, the charging roller can significantly reduce the amount of ozone generated as compared with a corona charging type charger, and can reduce adverse effects on the photoconductor. Further, in the present invention, it is possible and useful to use the charging roller without contacting the photoreceptor. Conventionally, the charging roller is used in contact with the photoreceptor, but silica and talc adhere to the charging roller due to repeated use, thereby promoting the abrasion of the photoreceptor and promoting the occurrence of filming. . By making the charging roller non-contact, their influence and contamination by toner are reduced. However, if the charging roller is used in a non-contact manner, the discharge may be uneven and the charging of the photoconductor may be unstable. In that case, by superimposing the AC component on the DC component, it is possible to suppress those effects. On the other hand, corotrons, scorotrons, and the like conventionally used as corona-charging type chargers can be effectively used, although the influence of ozone is large, the charging stability is high.

As the transfer means, the above-mentioned charger can be generally used. However, as shown in the figure, a combination of the transfer charger 10 and the separation charger 11 is effective.

The light sources such as the image exposure unit 5 and the neutralizing lamp 2 include a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, and a light emitting diode (LE).
D), semiconductor lasers (LD), electroluminescence (EL), and other general light-emitting materials can be used.
To irradiate only light in a desired wavelength range, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used.

In addition to the steps shown in FIG. 5, a light source and the like are provided with a transfer step, a charge removal step, a cleaning step,
Alternatively, by providing a process such as pre-exposure, the photoconductor is irradiated with light. However, the exposure of the photoreceptor in the charge elimination step has a great effect on fatigue on the photoreceptor, and in particular, a remarkable increase in residual potential may occur. Therefore, in some cases, it is possible to eliminate the charge by applying a reverse bias in the charging step or the cleaning step instead of removing the charge by exposure, which is preferable from the viewpoint of the durability of the photoconductor.

The toner developed on the photoreceptor 1 by the developing unit 6 is transferred to the transfer paper 9, but not all is transferred, and some toner remains on the photoreceptor 1. Such toner is removed from the photoconductor by the fur brush 14 and the blade 15. Cleaning may be performed only with a cleaning brush, and a known brush such as a fur brush or a mag fur brush is used as the cleaning brush.

The cleaning is a process for removing the toner and the like remaining on the photoreceptor after the transfer, and the abrasion of the photoreceptor is greatly promoted by repeatedly rubbing the photoreceptor with the above-mentioned blade or brush. An abnormal image may be generated due to scratching. Further, if the surface of the photoconductor is contaminated due to poor cleaning, it not only causes an abnormal image, but also greatly reduces the life of the photoconductor. In particular, when a layer containing a filler is provided on the surface of the photoreceptor to improve abrasion resistance, contaminants attached to the surface of the photoreceptor are not easily removed, and the influence of filming and image deterioration increases. , The effect is even greater. Therefore,
Enhancing the cleaning property of the photoconductor is very effective for improving the durability and image quality of the photoconductor.

As a means for improving the cleaning performance of the photosensitive member, there is known a method of reducing the friction coefficient of the surface of the photosensitive member. Methods for reducing the coefficient of friction on the surface of the photoreceptor are divided into two methods: a method in which various lubricating substances are contained in the surface of the photoreceptor, and a method in which a lubricating substance is supplied to the surface of the photoreceptor from the outside. The former is advantageous for a small-diameter photoreceptor because it has a high degree of freedom in layout around the engine, but has a problem in sustainability since the coefficient of friction is significantly increased by repeated use. On the other hand, the latter is not suitable for small-diameter photoreceptors because it is necessary to provide a component for supplying a lubricating substance, but because of its excellent durability, it is an effective means for increasing the durability of photoreceptors. is there. Among them, the method of attaching the photoreceptor to the photoreceptor at the time of development by incorporating the lubricating substance into the developer is not limited by the layout around the engine, and the effect of reducing the friction coefficient of the photoreceptor surface is also high. Therefore, this is a very effective means for increasing the durability of the photoconductor. Reducing the coefficient of friction on the surface of the photoreceptor not only increases cleaning performance, but also has many advantages for higher image quality, such as improved abrasion resistance, improved transfer efficiency, and suppression of image deterioration due to filming. have.

Examples of these lubricating substances include lubricating liquids such as silicone oil and fluorine oil, PTFE, P
Various fluorine-containing resins such as FA and PVDF, silicone resins, polyolefin resins, silicon grease, fluorine grease, paraffin wax, fatty acid esters,
Fatty acid metal salts such as zinc stearate, graphite, lubricating liquids and solids such as molybdenum disulfide, powders and the like,
When mixed with the developer, a powdery substance is preferable,
In particular, zinc stearate has very little adverse effect and can be used very effectively. However, if the coefficient of friction of the photoreceptor is too low, problems may occur in development. When the zinc stearate powder is contained in the toner, it is necessary to consider their balance and the effect on the toner.
0.3 wt% is more preferable.

When a positive (negative) charge is applied to the electrophotographic photosensitive member and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. If this is developed with negative (positive) polarity toner (electrostatic detection fine particles), a positive image can be obtained, and if it is developed with positive (negative) polarity toner, a negative image can be obtained.

A known method is applied to the developing means, and a known method is also used for the charge removing means.

FIG. 6 shows another example of the electrophotographic process according to the present invention. The photoreceptor 21 has, on a conductive support, a photosensitive layer showing the electric field intensity dependence of the quantum efficiency represented by the above formula (I), and further contains a filler in the outermost surface layer. 22b, charging by the charging charger 23, image exposure by the light source 24, development (not shown), transfer using the transfer charger 25, exposure before cleaning by the light source 26, cleaning by the brush 27, and static elimination by the light source 28 are repeatedly performed. It is.
In FIG. 6, the photoconductor 21 is irradiated with light for exposure before cleaning from the support side.

The above illustrated electrophotographic process is an example of the embodiment of the present invention, and other embodiments are of course possible. For example, in FIG. 6, the pre-cleaning exposure is performed from the support side, but this may be performed from the photosensitive layer side, or the image exposure and the erasing light irradiation may be performed from the support side.

On the other hand, in the light irradiation step, image exposure, pre-cleaning exposure, and charge removal exposure are shown, but in addition, pre-transfer exposure, pre-exposure of image exposure, and other known light irradiation steps are provided. Light irradiation can also be performed on the body.

The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, or may be incorporated in the apparatus in the form of a process cartridge. The process cartridge includes a photoreceptor, and further includes a charging unit, an exposing unit, a developing unit, a transferring unit, a cleaning unit, and a discharging unit.
Devices (parts). There are many shapes and the like of the process cartridge. As a general example, there is a process cartridge shown in FIG. The photoreceptor 16 is the photoreceptor of the present invention. The photoreceptor 16 has, on a conductive support, a photosensitive layer showing the electric field intensity dependence of the quantum efficiency represented by the formula (I), and contains a filler in the outermost layer. Do it.

[0205]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to embodiments, but the present invention is not limited by the embodiments. All parts are parts by weight.

Example 1 An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following compositions were sequentially coated and dried on an aluminum cylinder to form a 3.5 μm undercoat layer. An electrophotographic photoreceptor comprising a 0.2 μm charge generation layer and a 23 μm charge transport layer was formed. ◎ Coating solution for undercoat layer Titanium dioxide powder 400 parts Melamine resin 65 parts Alkyd resin 120 parts 2-butanone 400 parts

◎ Coating solution for charge generating layer 12 parts of bisazo pigment having the following structure

Embedded image Polyvinyl butyral 5 parts 2-butanone 200 parts Cyclohexanone 400 parts

◎ Charge transport layer coating liquid 1 A type polycarbonate 10 parts Charge transport material of the following structural formula (Ip: 5.4 eV) 7 parts

Embedded image Tetrahydrofuran 400 parts Cyclohexanone 150 parts

◎ Charge transport layer coating liquid 2 A type polycarbonate 10 parts Charge transport material of the following structural formula 7 parts

Embedded image Silica fine particles (average primary particle size: 0.1 μm, “KMPX-100” manufactured by Shin-Etsu Chemical) 3 parts Tetrahydrofuran 400 parts Cyclohexanone 150 parts The charge transport layer is formed by spraying the charge transport layer coating liquid 1 by an equivalent amount of 20 μm. Then, before the coating film was dried by touch, a charge transport layer coating liquid 2 was formed by a spray method equivalent to 3 μm to form a charge transport layer having a filler concentration gradient.

Example 2 A photoconductor was prepared by the same way as that of Example 1 except that the coating solutions 1 and 2 of the charge transport layer in Example 1 were changed to those having the following compositions. ◎ Coating liquid for charge transport layer 1 15 parts of a polymer charge transport material having the following structural formula (Ip: 5.4 eV)

Embedded image Tetrahydrofuran 400 parts Cyclohexanone 150 parts

◎ Charge transport layer coating liquid 2 15 parts of a polymer charge transport material having the following structural formula

Embedded image Silica fine particles (average primary particle size: 0.1 μm, “KMPX-100” manufactured by Shin-Etsu Chemical) 3 parts Tetrahydrofuran 400 parts Cyclohexanone 150 parts

Example 3 An undercoat layer and a charge generation layer in Example 1 were provided in the same manner.
On top of this, the charge transport layer coating solution 1 of Example 1 was
Was formed and dried by heating. Further, a protective layer having a thickness of 3 μm was formed on the charge transporting layer by using a coating liquid for a protective layer having the following composition to prepare an electrophotographic photoreceptor of the present invention. ◎ Coating solution for protective layer Z-type polycarbonate 10 parts Charge transporting material of the following structural formula 5 parts

Embedded image Alumina fine particles (average primary particle size: 0.3 μm, “AA-03” manufactured by Sumitomo Chemical Co., Ltd.) 2 parts 400 parts tetrahydrofuran 150 parts cyclohexanone

Example 4 A photoconductor was prepared by the same way as that of Example 3 except that the coating composition for the protective layer in Example 3 was changed to the following composition. ◎ Coating solution for protective layer 8 parts Z-type polycarbonate 7 parts of polymer charge transporting substance (Ip: 5.4 eV) having the following structural formula

Embedded image Alumina fine particles (Average primary particle size: 0.3 μm, “AA-03” manufactured by Sumitomo Chemical Co., Ltd.) 2 parts Methylene chloride 80 parts

Example 5 A photoconductor was prepared by the same way as that of Example 1 except that the coating solution for the charge generation layer was changed to the following. ◎ Coating liquid for charge generating layer 12 parts of bisazo pigment having the following structure

Embedded image Polyvinyl butyral 5 parts 2-butanone 200 parts Cyclohexanone 400 parts

Example 6 A photoconductor was prepared by the same way as that of Example 3 except that the coating liquid for the charge generation layer was changed to the following. ◎ Coating liquid for charge generating layer 12 parts of bisazo pigment having the following structure

Embedded image Polyvinyl butyral 5 parts 2-butanone 200 parts Cyclohexanone 400 parts

Comparative Example 1 In Example 3, 28 μm
A photoconductor was prepared in the same manner as in Example 3 except that the charge transport layer was formed.

Comparative Example 2 In Example 3, 36 μm
A photoconductor was prepared in the same manner as in Example 3 except that the charge transport layer was formed.

Comparative Example 3 In Example 1, only the charge transport layer coating liquid 1 was used.
A photoconductor was prepared by the same way as that of Example 1 except that a charge transport layer of 23 μm was formed.

Comparative Example 4 A photoconductor was prepared by the same way as that of Example 1 except that the coating composition for the charge generation layer was changed to the composition below. ◎ Coating liquid for charge generating layer 12 parts of bisazo pigment having the following structure

Embedded image Polyvinyl butyral 5 parts 2-butanone 200 parts Cyclohexanone 400 parts

The photoconductors of Examples 1 to 6 and Comparative Examples 1 to 4 produced as described above were measured for quantum efficiency using a measuring device disclosed in Japanese Patent Application Laid-Open No. 60-100167.

First, the photosensitive member was charged at a charging voltage of -6.0 kV until the surface potential of the photosensitive member became -800 V, and the photosensitive member was irradiated with tungsten light (660 nm) through a spectroscope to determine its light attenuation curve. Next, the capacitance of the photoconductor is determined,
According to the method described in Japanese Patent No. 2838891, the photoreceptor quantum efficiency was determined, plotted against the electric field intensity, and the dependence (slope) b thereof was determined.

The photoreceptor manufactured as described above is
And the initial image was evaluated using a 660 nm semiconductor laser (image writing with a polygon mirror) as the image exposure light source. However, the image rank was classified as follows. The results are shown in Table 1. ◎: Level at which there is no problem in image quality 画像: Level of image quality slightly deteriorated, but there is no problem with visual observation △: Level at which image quality is degraded even by visual observation ×: Level at which there is a serious problem in image quality

The above results are shown in Table 1.

[0224]

[Table 1]

From the results shown in Table 1, it was found that by using a specific azo pigment as the charge generating substance and adopting the constitution of the present invention,
In each case, good images could be obtained. However, in the case of a photosensitive member having a slope b of 0.5 or more or a photosensitive layer having a thickness of the photosensitive layer or the charge transport layer of more than 25 μm, deterioration in sensitivity or image bleeding occurred. As a result, it was confirmed that the image density and the resolution were reduced, and the image quality was deteriorated.

Example 7 An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following compositions were sequentially applied and dried on an aluminum cylinder to form a 3.5 μm undercoat layer. An electrophotographic photoreceptor comprising a 0.2 μm charge generation layer and a 21 μm charge transport layer was formed. ◎ Coating solution for undercoat layer Titanium dioxide powder 400 parts Melamine resin 65 parts Alkyd resin 120 parts 2-butanone 400 parts

◎ Coating solution for charge generation layer 8 parts of titanyl phthalocyanine having an X-ray diffraction pattern shown in FIG. 8 8 parts of polyvinyl butyral 5 parts 400 parts of 2-butanone

◎ Charge transport layer coating liquid 1 C-type polycarbonate 10 parts Charge transport material of the following structural formula (Ip: 5.4 eV) 7 parts

Embedded image 80 parts of methylene chloride

◎ Coating solution for charge transport layer 2 C-type polycarbonate 10 parts Charge transport material of the following structural formula 7 parts

Embedded image Alumina fine particles (average primary particle size: 0.3 μm, “AA-03” manufactured by Sumitomo Chemical Co., Ltd.) 2 parts Methylene chloride 80 parts The charge transport layer was formed by spraying the charge transport layer coating liquid 1 in an amount equivalent to 18 μm. Subsequently, before the coating film was dried by touch, a charge transport layer coating liquid 2 was formed by a spray method equivalent to 3 μm to form a charge transport layer having a filler concentration gradient.

Example 8 The same procedures as in Example 7 were carried out except that the charge transporting substance contained in the coating liquid 2 for the charge transporting layer in Example 7 was changed to the following charge transporting substance (Ip: 5.5 eV). An electrophotographic photosensitive member was manufactured.

Embedded image

Example 9 A photoconductor was prepared by the same way as that of Example 7 except that the coating solutions 1 and 2 of the charge transport layer in Example 7 were changed to those having the following compositions. ◎ Coating liquid for charge transport layer 1 15 parts of a polymer charge transport material having the following structural formula (Ip: 5.4 eV)

Embedded image Tetrahydrofuran 400 parts Cyclohexanone 150 parts

◎ Coating solution for charge transport layer 2 15 parts of a polymer charge transport material having the following structural formula

Embedded image Alumina fine particles (average primary particle size: 0.3 μm, “AA-03” manufactured by Sumitomo Chemical Co., Ltd.) 2 parts Tetrahydrofuran 400 parts Cyclohexanone 150 parts

Example 10 An undercoat layer and a charge generation layer in Example 7 were provided in the same manner.
A charge transport layer coating solution of the following composition
Was formed and dried by heating. Further, a protective layer having a thickness of 3 μm was formed on the charge transporting layer using a coating liquid for a protective layer having the following composition, thereby producing an electrophotographic photoreceptor of the present invention. ◎ Coating liquid for charge transport layer Z-type polycarbonate 10 parts Charge transport material of the following structural formula 8 parts

Embedded image 80 parts of methylene chloride

◎ Coating solution for protective layer Z-type polycarbonate 10 parts Charge transporting material of the following structural formula 8 parts

[Of 60] Alumina fine particles (average primary particle size: 0.3 μm, “AA-03” manufactured by Sumitomo Chemical Co., Ltd.) 2 parts 400 parts tetrahydrofuran 150 parts cyclohexanone

Example 11 Electrophotography was performed in the same manner as in Example 10 except that the charge transport material contained in the protective layer coating solution in Example 10 was changed to the following charge transport material (Ip: 5.5 eV). A photoreceptor was produced.

Embedded image

Example 12 A photoconductor was prepared by the same way as that of Example 10 except that the coating composition for the protective layer in Example 10 was changed to the following composition. ◎ Protective layer coating liquid Z-type polycarbonate 8 parts Polymer charge transport material of the following structural formula 7 parts

Embedded image Alumina fine particles (average primary particle size: 0.3 μm, “AA-03” manufactured by Sumitomo Chemical Co., Ltd.) 2 parts Methylene chloride 80 parts

Comparative Example 5 A photoconductor was prepared by the same way as that of Example 10 except that the charge transport layer of 27 μm was formed using the charge transport layer coating liquid 1 of Example 7.

Comparative Example 6 A photoconductor was prepared by the same way as that of Example 12 except that the charge transport layer of 35 μm was formed using the charge transport layer coating liquid 1 of Example 7.

Comparative Example 7 In Example 7, only the charge transport layer coating liquid 1 was used.
A photoconductor was prepared by the same way as that of Example 7 except that a charge transport layer of 21 μm was formed.

Comparative Example 8 A photoconductor was prepared by the same way as that of Example 7 except that the coating composition for the charge generation layer was changed to the composition below. ◎ Coating solution for charge generation layer 12 parts of trisazo pigment having the following structure

Embedded image Polyvinyl butyral 5 parts 2-butanone 200 parts Cyclohexanone 400 parts

The photoreceptors of Examples 7 to 12 and Comparative Examples 5 to 8 prepared as described above were described in JP-A-60-100.
Quantum efficiency was measured using a measuring device disclosed in Japanese Patent Publication No. 167.

First, the photosensitive member was charged at a charging voltage of -6.0 kV until the surface potential of the photosensitive member became -800 V, and was irradiated with tungsten light (780 nm) through a spectroscope, and its light attenuation curve was obtained. Next, the capacitance of the photoconductor is determined,
According to the method described in Japanese Patent No. 2838891, the photoreceptor quantum efficiency was determined, plotted against the electric field intensity, and the dependence (slope) b thereof was determined.

Further, the photosensitive member manufactured as described above was used in FIG.
Is attached to the cartridge for electrophotographic process (except for the pre-cleaning exposure) shown in
The initial image was evaluated as a 0 nm semiconductor laser (image writing with a polygon mirror). However, the image rank was classified as follows. Table 2 shows the results. ◎: Level at which there is no problem in image quality 画像: Level of image quality slightly deteriorated, but there is no problem with visual observation △: Level at which image quality is degraded even by visual observation ×: Level at which there is a serious problem in image quality

The above results are shown in Table 2.

[0245]

[Table 2]

From the results in Table 2, it can be seen that good images could be obtained by using the specific titanyl phthalocyanine pigment as the charge generating material and employing the constitution of the present invention, but the inclination b was 0.5. In the photoreceptor and the photoreceptor in which the thickness of the photosensitive layer or the charge transport layer is greater than 25 μm, it was confirmed that the image density and resolution were reduced due to sensitivity deterioration or image bleeding, and image quality was deteriorated. Was.

Example 13 An undercoat layer coating solution having the following composition, a charge generation layer coating solution, a charge transport layer coating solution, and a protective layer coating solution having the following compositions were sequentially applied onto an electroformed Ni belt. Dried, 3 μm undercoat layer,
0.3 μm charge generation layer, 19 μm charge transport layer, 2 μm
m of the electrophotographic photoreceptor comprising the protective layer. ◎ Coating liquid for undercoat layer Titanium dioxide powder 100 parts Alcohol-soluble nylon 30 parts Methanol 400 parts Butanol 200 parts

◎ Coating liquid for charge generating layer 12 parts of bisazo pigment having the following structure

Embedded image Polyvinyl butyral 5 parts 2-butanone 200 parts Cyclohexanone 400 parts

◎ Coating solution for charge transport layer Z-type polycarbonate 10 parts Charge transport material of the following structural formula 7 parts

Embedded image 100 parts of tetrahydrofuran

◎ Coating solution for protective layer Z-type polycarbonate 10 parts Charge transporting substance of the following structural formula 7 parts

Embedded image Titanium oxide fine particles (average primary particle size: 0.3 μm, “CR97” manufactured by Ishihara Sangyo) 2 parts Tetrahydrofuran 100 parts

Example 14 A photoconductor was prepared by the same way as that of Example 13 except that the titanium oxide fine particles contained in the coating solution for the protective layer were changed to the following organic fillers. Eposter S (Nippon Shokubai) 2parts

Example 15 A photoconductor was prepared by the same way as that of Example 13 except that the titanium oxide fine particles contained in the coating solution for the protective layer were changed to tin oxide having an average primary particle size of 0.1 μm. Produced.

Example 16 A photoconductor was prepared by the same way as that of Example 13 except that the titanium oxide fine particles contained in the coating liquid for the protective layer were changed to alumina fine particles having an average primary particle size of 0.9 μm. Produced.

Example 17 In Example 13, with respect to 2 parts of titanium oxide contained in the coating liquid for the protective layer, alumina fine particles having an average primary particle diameter of 0.3 μm and silica fine particles having an average primary particle diameter of 0.1 μm were used. 1
A photoconductor was prepared by the same way as that of Example 13 except that the content was changed by part.

Example 18 A photoconductor was prepared by the same way as that of Example 13 except that the charge transporting substance contained in the coating solution for the protective layer was removed.

Comparative Example 9 A photoconductor was prepared by the same way as that of Example 13 except that the coating solution of the charge generating layer in Example 13 was changed to the following composition. ◎ Coating liquid for charge generating layer 12 parts of bisazo pigment having the following structure

Embedded image Polyvinyl butyral 5 parts 2-butanone 200 parts Cyclohexanone 400 parts

The photoreceptors of Examples 13 to 18 and Comparative Example 9 produced as described above were measured for quantum efficiency using an electrostatic copying paper test apparatus (Kawaguchi Electric: EPA8100).

First, the photosensitive member was charged at a charging voltage of -6.0 kV until the surface potential of the photosensitive member became -800 V, and the photosensitive member was irradiated with tungsten light (660 nm) through a spectroscope to determine its light attenuation curve. Next, the capacitance of the photoconductor is determined,
According to the method described in Japanese Patent No. 2838891, the photoreceptor quantum efficiency was determined, plotted against the electric field intensity, and the dependence (slope) b thereof was determined.

Further, the photoreceptor manufactured as described above was used as shown in FIG.
And the initial image was evaluated using a 660 nm semiconductor laser (image writing with a polygon mirror) as the image exposure light source. However, the image rank was classified as follows. These results are shown in Table 3. ◎: Level at which there is no problem in image quality 画像: Level of image quality slightly deteriorated, but there is no problem with visual observation △: Level at which image quality is degraded even by visual observation ×: Level at which there is a serious problem in image quality

[0260]

[Table 3]

From the results shown in Table 3, all the photoconductors according to the present invention had satisfactory image quality. However, inorganic fillers were selected, and among inorganic fillers, fillers having relatively high resistance were selected. The tendency that the image quality was further improved by using was confirmed. It was also confirmed that when the average primary particle size of the filler was very large, the image quality level was slightly lowered.

Example 19 The procedure of Example 6 was repeated except that the coating liquid for the protective layer was changed to a coating liquid having the following composition, and a protective layer of about 5 μm was formed on the charge transport layer. Thus, an electrophotographic photosensitive member was manufactured. ◎ Protective layer coating liquid Z-type polycarbonate 10 parts Charge transporting substance of the following structural formula 7 parts

Embedded image Alumina fine particles (average primary particle diameter: 0.3 μm, “AA-03” Sumitomo Chemical 2 parts tetrahydrofuran 400 parts cyclohexanone 150 parts

Example 20 An electrophotographic photosensitive member was produced in the same manner as in Example 19 except that the coating liquid for the protective layer was changed to a coating liquid having the following composition. ◎ Protective layer coating liquid Z-type polycarbonate 10 parts Charge transporting substance of the following structural formula 7 parts

Embedded image Alumina fine particles treated with titanate coupling (average primary particle size: 0.3 μm, “AA-03” manufactured by Sumitomo Chemical Co., Ltd., surface treatment amount: 5 wt%) 2 parts Tetrahydrofuran 400 parts Cyclohexanone 150 parts

Example 21 An electrophotographic photosensitive member was produced in the same manner as in Example 19 except that the coating liquid for the protective layer was changed to a coating liquid having the following composition. ◎ Protective layer coating liquid Z-type polycarbonate 10 parts Charge transporting substance of the following structural formula 7 parts

Embedded image Alumina fine particles (average primary particle size: 0.3 μm, “AA-03” manufactured by Sumitomo Chemical Co., Ltd.) 2 parts Unsaturated polycarboxylic acid polymer wet dispersant (acid value 180 mgKOH / g, “BYK-P104” manufactured by BYK Chemie) 0 .04 parts Tetrahydrofuran 400 parts Cyclohexanone 150 parts Dispersant content A, acid value B, filler content C
Then, (A × B) /C=3.6.

Example 22 An electrophotographic photosensitive member was prepared in the same manner as in Example 21, except that the thickness of the charge transport layer was changed to 16 μm.

Example 23 An electrophotographic photosensitive member was produced in the same manner as in Example 21 except that the thickness of the charge transport layer was changed to 24 μm.

Example 24 The procedure of Example 10 was repeated except that the coating liquid for the protective layer was changed to a coating liquid having the following composition, and a protective layer of about 5 μm was formed on the charge transport layer. Thus, an electrophotographic photosensitive member was manufactured. ◎ Coating solution for protective layer Z-type polycarbonate 10 parts Charge transporting material of the following structural formula 8 parts

Embedded image Alumina fine particles (average primary particle size: 0.3 μm, “AA-03” manufactured by Sumitomo Chemical Co., Ltd.) 2 parts Unsaturated polycarboxylic acid polymer wetting and dispersing agent (acid value 180 mgKOH / g, “BYK-P104” manufactured by BYK Chemie) 0 0.06 parts Tetrahydrofuran 400 parts Cyclohexanone 150 parts Dispersant content A, acid value B, filler content C
Then, (A × B) /C=5.4.

Example 25 An electrophotographic photosensitive member was prepared in the same manner as in Example 24 except that the thickness of the charge transport layer was changed to 16 μm.

Example 26 An electrophotographic photosensitive member was produced in the same manner as in Example 24 except that the thickness of the charge transport layer was changed to 24 μm.

Comparative Example 10 An electrophotographic photosensitive member was produced in the same manner as in Example 21, except that the thickness of the charge transport layer was changed to 30 μm.

Comparative Example 11 An electrophotographic photosensitive member was produced in the same manner as in Example 24 except that the thickness of the charge transport layer was changed to 30 μm.

The photoreceptor produced as described above was electrophotographically processed as shown in FIG. 5 (however, there was no exposure before cleaning).
And an image exposure light source of 660 nm (Example 22,
The initial image was evaluated as a semiconductor laser (image writing with a polygon mirror) of 23, 24 and Comparative Example 11 (780 nm only). However, the image rank was classified as follows. These results are shown in Table 4. ◎: Level at which there is no problem in image quality 画像: Level of image quality slightly deteriorated, but there is no problem with visual observation △: Level at which image quality is degraded even by visual observation ×: Level at which there is a serious problem in image quality

[0273]

[Table 4]

When the thickness of the protective layer was increased, the image density tended to decrease due to the influence of the residual potential. However, when the polycarboxylic acid compound is contained as a dispersant, the residual potential can be reduced, and a good image can be obtained even when the thickness of the protective layer is large.
However, when the thickness of the photosensitive layer or the charge transport layer was greater than 25 μm, the resolution tended to decrease.

Next, Examples 1-26 and Comparative Examples 1-11
The photoreceptor was mounted on a laser printer remodeling machine of the electrophotographic process shown in FIG.
As a semiconductor laser (image writing by a polygon mirror), a charging roller was used for charging, 30,000 sheets were continuously printed, and the image was evaluated after printing 30,000 sheets. The wear amount was calculated from the difference in film thickness between the initial stage and after printing 30,000 sheets. However, the image rank was classified as follows. Table 5 shows the results. ◎: Level at which there is no problem in image quality 画像: Level of image quality slightly deteriorated, but there is no problem with visual observation △: Level at which image quality is degraded even by visual observation ×: Level at which there is a serious problem in image quality

[0276]

[Table 5]

The light-area potential tended to increase due to repeated use, and the image density tended to slightly decrease as a whole. However, by including a polycarboxylic acid compound as a dispersant, even after repeated use. A good image can be obtained. Further, as the thickness of the photosensitive layer or the charge transport layer increases, the effect of image deterioration after repeated use tends to increase,
This was noticeable when the film thickness was greater than m. By adopting the configuration of the present invention, it has become possible to obtain a photoreceptor capable of maintaining high sensitivity even after repeated use and greatly reducing image quality deterioration.

Example 27 The electrophotographic photosensitive member of Example 26 was mounted on an electrophotographic process cartridge (however, there was no exposure before cleaning), and a digital copier was modified using a 780 nm semiconductor laser as an image exposure light source. A total of 100,000 sheets were printed continuously by a printing machine, and the images and abrasion loss at the initial stage and after the printing of 100,000 sheets were evaluated. A charging roller was used for charging. Table 6 shows the results.

Example 28 A digital copying machine in which the electrophotographic photosensitive member of Example 26 was mounted on an electrophotographic process cartridge (however, there was no exposure before cleaning) and an image exposure light source was a 780 nm semiconductor laser. A total of 100,000 sheets were printed continuously by a printing machine, and the image findings and the amount of wear at the initial stage and after the printing of 100,000 sheets were evaluated. A Teflon (registered trademark) tape having a thickness of 50 μm was wrapped around the non-image area around the used charging roller, so that the image area of the photoreceptor was not in direct contact with the charging roller. Table 6 shows the results.

Example 29 The electrophotographic photosensitive member of Example 26 was mounted on an electrophotographic process cartridge (however, there was no exposure before cleaning), and a digital copier was modified using a 780 nm semiconductor laser as an image exposure light source. A total of 100,000 sheets were printed continuously by a printing machine, and the images and abrasion loss at the initial stage and after the printing of 100,000 sheets were evaluated. A 50 μm thick Teflon (registered trademark) tape is wrapped around the non-image area on the used charging roller, and the image area of the photoconductor is shaped so as not to directly contact the charging roller. Further, AC (2 kHz) is applied to the charging roller.
z, 1.8 kVpp) + DC (−750 V) was applied. Table 6 shows the results.

Example 30 The electrophotographic photosensitive member of Example 26 was mounted on an electrophotographic process cartridge (however, there was no exposure before cleaning), and a digital copier was modified using an image exposure light source of a 780 nm semiconductor laser. A total of 100,000 sheets were printed continuously by a printing machine. At that time, the image and the wear amount after the initial and after 100,000 sheets were printed were evaluated. A Teflon (registered trademark) tape having a thickness of 50 μm is wrapped around the surface of the non-image forming area on the charging roller used so as not to come into direct contact with the image area of the photoreceptor, and AC (2 kHz, 1.8
kVpp) + DC (−750 V) was applied. Further, 0.1 part by weight of zinc stearate was added to 100 parts by weight of the toner. Table 6 shows the results.

[0282]

[Table 6]

From the results shown in Table 6, when printing 100,000 sheets, the background stain became conspicuous. However, the background stain could be reduced by keeping the charging roller out of contact with the photosensitive member. . However, unevenness in the image density was slightly confirmed due to a decrease in charging stability. Therefore, by superimposing AC on the charging roller,
These effects can be suppressed. On the other hand, A
It was confirmed that the amount of abrasion of the photoreceptor was increased by superimposing C. However, by adding an appropriate amount of zinc stearate as a lubricating substance to the toner, the abrasion resistance was improved and a good image was obtained for a long time. It became possible to obtain.

[0284]

According to the present invention, the sensitivity can be increased by using a charge generating material having a small electric field dependence of quantum efficiency such that b in the formula (I) is 0.5 or less. By including a filler in the outermost surface layer, high durability has been realized, and as a result, film abrasion of the photosensitive layer has been greatly reduced.
Further, the image density fluctuation was reduced. Furthermore, the film thickness of the photosensitive layer was reduced to 25 μm
A photoreceptor that achieves high image quality can be provided by being able to set the following thin film thickness. In addition, by using the photoreceptor, high-speed printing is possible, the exchange of the photoreceptor is not required, and even in repeated use, an electrophotographic method in which a high quality image is stably obtained for a long time, An electrophotographic apparatus and a process cartridge for electrophotography are provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of the electrophotographic photosensitive member of the present invention.

FIG. 2 is a cross-sectional view illustrating another example of the electrophotographic photosensitive member of the present invention.

FIG. 3 is a cross-sectional view illustrating another example of the electrophotographic photosensitive member of the present invention.

FIG. 4 is a cross-sectional view illustrating another example of the electrophotographic photosensitive member of the present invention.

FIG. 5 is a schematic view of an example of an electrophotographic method and an electrophotographic apparatus according to the present invention.

FIG. 6 is a schematic view showing another example of the electrophotographic method according to the present invention.

FIG. 7 is a schematic view showing a general example of a process cartridge of the present invention.

FIG. 8 is an X-ray diffraction pattern of titanyl phthalocyanine used in the charge generation layer of Example 7.

[Explanation of symbols]

 31 conductive support 33 single-layer photosensitive layer 35 charge generation layer 37 charge transport layer 39 protective layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 5/06 371 G03G 5/06 371 5/07 103 5/07 103 9/08 372 9/08 372 15 / 02 102 15/02 102 21/00 21/00 (72) Inventor Akihiko Matsuyama 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Satoshi Kurimoto 1 Nakamagome, Ota-ku, Tokyo 3-6, Ricoh Co., Ltd. (72) Inventor Eri, Paper 1-3-6, Nakamagome, Ota-ku, Tokyo F-term (reference) 2H005 AA08 CA12 CA30 2H068 AA03 AA04 AA08 AA14 AA19 AA20 AA28 AA31 AA32 AA35 AA37 AA39 BA04 BA39 BA47 BA53 BA57 BB49 CA06 CA29 CA33 FA27 2H134 GA01 GB02 KG03 KG07 KG08 KH02 KH11 KH15 LA00 2H200 FA09 FA12 GA15 GA23 GA24 GA33 GA34 GA44 GB02 GB13 HA11 HA12 H A28 HB03 HB12 HB28 HB48 JA02 JB20 KA07 KA14 NA06 NA09 NA10

Claims (39)

[Claims] 1. An electrophotographic photosensitive member comprising a conductive support and a single-layer photosensitive layer containing at least a charge-generating substance and a charge-transporting substance. When the relationship between the quantum efficiency η of the photoreceptor and the electric field strength E applied to the photoreceptor is represented by the following formula (I), b is 0.5 or less, and the single-layer photosensitive layer An electrophotographic photoreceptor, wherein the thickness of the electrophotographic photosensitive member is 25 μm or less. η = a × E ^b (I) (where, η is the quantum efficiency of the photoconductor, a is a constant, and E is the electric field intensity.) 2. An electrophotographic photosensitive member comprising a conductive support provided with a laminated structure of a charge generating layer containing at least a charge generating substance and a charge transporting layer containing a charge transporting substance. When the outermost surface layer contains one or more kinds of fillers and the relationship between the quantum efficiency η of the photoreceptor and the electric field intensity E applied to the photoreceptor is expressed by the following formula (I), b is 0.5 or less. An electrophotographic photosensitive member, wherein the charge transport layer has a thickness of 25 μm or less. η = a × E ^b (I) (where, η is the quantum efficiency of the photoconductor, a is a constant, and E is the electric field intensity.) 3. The electrophotographic photoreceptor according to claim 1, wherein a protective layer is formed as an outermost layer on the single-layer photosensitive layer or the charge transport layer. 4. The single-layer photosensitive layer or the charge transport layer has a thickness of 20 μm or less.
The electrophotographic photosensitive member according to any one of the above. 5. The charge generating material according to claim 1, wherein the charge generating material is an azo pigment or a phthalocyanine pigment.
The electrophotographic photosensitive member according to any one of the above. 6. The electrophotographic photosensitive member according to claim 5, wherein the azo pigment is an azo pigment represented by the following formula (II). Embedded image (In the formula (II), Cp ₁ and Cp ₂ represent a coupler residue.
R ₂₀₁ and R ₂₀₂ each represent any of a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, and a cyano group;
They may be the same or different. Cp ₁ and Cp ₂ are represented by the following formula (III): In the formula (III), R ₂₀₃ represents any one of a hydrogen atom, an alkyl group, and an aryl group, and R ₂₀₄ , R ₂₀₅ , R ₂₀₆ , R ₂₀₇ ,
R ₂₀₈ represents any of a hydrogen atom, a nitro group, a cyano group, a halogen atom, a trifluoromethyl group, an alkyl group, an alkoxy group, a dialkylamino group, and a hydroxyl group, and Z is a substituted or unsubstituted aromatic carbocyclic ring Alternatively, it represents an atom group necessary for constituting a substituted or unsubstituted aromatic heterocyclic ring. ) 7. The electrophotographic photoreceptor according to claim 6, wherein Cp ₁ and Cp ₂ of the azo pigment are different from each other. 8. The electrophotographic photoreceptor according to claim 5, wherein said phthalocyanine pigment is titanyl phthalocyanine. 9. The method according to claim 8, wherein the titanyl phthalocyanine is CuK.
As a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to characteristic X-ray (wavelength 1.514 °) of α, at least 2
9. The electrophotographic photoreceptor according to claim 8, wherein the photoreceptor is titanyl phthalocyanine having a maximum diffraction peak at 7.2 °. 10. The photoconductor according to claim 1, wherein the filler contained in the outermost surface layer is an inorganic material.
The electrophotographic photosensitive member according to any one of the above. 11. An electrophotographic photoconductor according to claim 10, wherein said inorganic material contains at least one kind of metal oxide. 12. The electrophotographic photoconductor according to claim 11, wherein the metal oxide is at least one selected from silica, alumina and titanium oxide. 13. The electrophotographic photosensitive member according to claim 10, wherein at least one of the inorganic materials has been subjected to a surface treatment with at least one surface treatment agent. 14. The electrophotographic photoreceptor according to claim 13, wherein the surface treating agent is at least a titanate coupling agent, a higher fatty acid or a metal salt of a higher fatty acid. 15. The electrophotographic photoreceptor according to claim 13, wherein the amount of the surface treatment of the inorganic material subjected to the surface treatment is 2 to 30 wt%. 16. An inorganic material having an average primary particle size of 0.1 to 0.1.
2. The structure according to claim 1, wherein the thickness is from 0.01 to 0.8 .mu.m.
The electrophotographic photosensitive member according to any one of 0 to 15. 17. The electrophotographic photoreceptor according to claim 1, wherein the filler-containing layer contains a dispersant. 18. The method according to claim 18, wherein the dispersant is 10 to 400 (mg KO).
The electrophotographic photosensitive member according to claim 17, having an acid value of H / g). 19. The electrophotographic photoreceptor according to claim 17, wherein the dispersant is an organic compound containing at least one carboxyl group in the structure. 20. The electrophotographic photoconductor according to claim 19, wherein the organic compound containing at least one carboxyl group in the structure is a polycarboxylic acid derivative. 21. When the content of the dispersant is A, the acid value of the dispersant is B, and the content of the filler is C,
The electrophotographic photoreceptor according to any one of claims 17 to 20, wherein A, B, and C satisfy the following relational expression. 0.1 ≦ (A × B) / C ≦ 20 22. The electrophotographic photosensitive member according to claim 3, wherein the protective layer contains a charge transporting substance. 23. The following relational expression holds between the ionization potential Ip of the charge transport material contained in the protective layer and that of the charge transport material contained in the single-layer photosensitive layer or the charge transport layer. The electrophotographic photosensitive member according to claim 22, wherein I of the charge transport material contained in the protective layer
p ≦ Ip of the charge transport material contained in the single-layer photosensitive layer or the charge transport layer 24. The electrophotographic photoconductor according to claim 22, wherein the charge transport material contained in the protective layer contains a polymer charge transport material. 25. The polymer charge transport material according to claim 24, wherein the polymer is a polycarbonate containing at least a triarylamine structure in a main chain and / or a side chain.
The electrophotographic photosensitive member according to the above. 26. An electrophotographic photosensitive member comprising:
An electrophotographic method in which image exposure, development, and transfer are repeatedly performed, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 25. 27. An electrophotographic photosensitive member comprising:
A digital electrophotographic method in which image exposure, development, and transfer are repeatedly performed, and an electrostatic latent image is written on a photoconductor by an LD or an LED during image exposure. Item 25. An electrophotographic method, comprising the electrophotographic photosensitive member according to any one of Items 1 to 25. 28. At least charging means, image exposure means,
2. An electrophotographic apparatus comprising a developing means, a transfer means and an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is provided.
An electrophotographic apparatus, wherein the electrophotographic photoreceptor is any one of the above-described items. 29. At least charging means, image exposure means,
An electrophotographic apparatus including a developing unit, a transfer unit, and an electrophotographic photosensitive member, wherein an electrostatic latent image is written on the photosensitive member by using an LD or an LED as an image exposure unit. An electrophotographic apparatus according to claim 1, wherein said electrophotographic photosensitive member is the electrophotographic photosensitive member according to claim 1. 30. The electrophotographic apparatus according to claim 28, wherein the electrophotographic apparatus uses a roller-shaped charging member as the charging means. 31. The electrophotographic apparatus according to claim 30, wherein in the electrophotographic apparatus using the roller-shaped charging member as a charging unit, the charging member and the photoconductor are not in contact in an image forming area. apparatus. 32. The electrophotographic apparatus according to claim 30, wherein in the electrophotographic apparatus using the roller-shaped charging member as a charging unit, an alternating current component is superimposed on a direct current component to charge the photosensitive member. apparatus. 33. An electrophotographic apparatus according to claim 28, wherein said electrophotographic apparatus has means for attaching a lubricating substance to the surface of said photoreceptor. 34. In the electrophotographic apparatus, the photoconductor is developed by using a developer containing at least one lubricating substance as a developer used when developing a latent image on the photoconductor. The electrophotographic apparatus according to claim 33, wherein the lubricating substance is attached to a surface. 35. The electrophotographic apparatus according to claim 33, wherein the lubricating substance is attached to the surface of the photoreceptor by externally bringing the lubricating substance into contact with the surface of the photoreceptor. . 36. The electrophotographic apparatus according to claim 33, wherein said at least one lubricating substance is zinc stearate. 37. The electrophotographic apparatus according to claim 33, wherein at least one kind of lubricating substance is a fluorine compound. 38. A process cartridge for an electrophotographic apparatus comprising at least an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 25. A process cartridge for an electrophotographic apparatus. 39. A process cartridge for an electrophotographic apparatus according to claim 38, wherein the process cartridge is used for the electrophotographic apparatus according to any one of claims 28 to 37.