JP2002351114A - Electrophotographic photoreceptor and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoreceptor in which stable images with high picture quality can be formed for repeated use and to provide an electrophotographic device in which images with high picture quality can be stably obtained even for repeated use. SOLUTION: In the electrophotographic photoreceptor, the distribution of the particle size of the filler in a protective layer shows continuous or successive increase from the photosensitive layer side to the surface side. The photoreceptor is used for the electrophotographic device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive member having high sensitivity, high resolution and high durability. Further, the present invention relates to an electrophotographic method, an electrophotographic apparatus, and an electrophotographic process cartridge using a photoconductor provided with a surface layer having a specific configuration.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, the Carlson process and various deformation processes thereof are known, and are widely used in copiers, printers, and the like. Among the photoreceptors used in such an electrophotographic method, those using an organic photosensitive material have recently begun to be used because of their advantages such as low cost, mass productivity, and no pollution.
Organic electrophotographic photoreceptors include a photoconductive resin represented by polyvinyl carbazole (PVK), PVK-TNF
(2,4,7-trinitrofluorenone), a charge transfer complex type represented by (2,4,7-trinitrofluorenone), a pigment dispersion type represented by phthalocyanine-binder, and a function-separated type photoconductor using a combination of a charge generating substance and a charge transporting substance. And the like, and particularly, a function-separated type photoreceptor has been receiving attention.

The mechanism of the formation of an electrostatic latent image in a photoreceptor of the function separation type is as follows. When the photoreceptor is charged and irradiated with light, the light passes through a transparent charge transporting layer and is charged by a charge generating substance in the charge generating layer. The absorbed charge-generating substance, which has absorbed light, generates a single charge, which is injected into the charge transport layer, moves through the charge transport layer according to the electric field generated by the charge, and removes the charge on the photoreceptor surface. The latent image is formed by neutralization. In a function-separated type photoreceptor, it is known and useful to use a charge transport material having absorption mainly in the ultraviolet region and a charge generation material having absorption mainly in the visible region.

In recent years, there has been a demand for a photoreceptor having a smaller diameter and a machine and a photoreceptor having higher durability (longer life). As described above, the development of vigorous materials for organic photoreceptors has ensured high sensitivity and high electrostatic durability. However, it is the present ability that the mechanical durability, particularly the wear resistance, is not always sufficient. In view of this point, photoconductors having a function of improving mechanical durability on the surface of an organic photoconductor have been proposed. Most of these studies have examined the type of binder resin used for the outermost layer of the photoreceptor, but have not always been satisfactory.

Another idea is to use a protective layer on the outermost surface of the photoreceptor. The examination of the protective layer as the surface layer of the photoconductor starts with an inorganic photoconductor, and is described in, for example, Japanese Patent Publication No. 2-3171 and Japanese Patent Publication No. 2-7.
No. 058 and Japanese Patent Publication No. 3-43618. When the protective layer was provided on the surface of the inorganic photoreceptor, a filler having a relatively low resistance was favorably used for the protective layer. Therefore, when the photoreceptor is charged, the surface of the photoreceptor is often charged rather than charged on the surface of the protective layer or on the interface between the protective layer and the inorganic photosensitive layer. Indeed, when the latent image is formed not on the surface of the photoconductor but inside the protective layer (including the interface with the inorganic photoconductive layer), there is an advantage that the effect of the shape (scratch etc.) of the surface of the photoconductor is reduced. Was. However, when the surface layer is to have a function as a protective layer, it is necessary to add a large amount of a conductive metal oxide as a filler to be added to the surface layer. In this case, even if the transparency of the surface layer is ensured by the selection of the material, the bulk or the surface resistance of the surface layer is reduced, so that there is a case where a defect such as image blurring appears upon repeated use. In order to solve such disadvantages, Japanese Patent Publication No. 2-7057 and Japanese Patent No. 2675035 disclose a method of changing the concentration of a conductive metal oxide in a surface layer in a depth direction from a coating film surface. ing. As a result, image blur and flow are eliminated.

As a method for eliminating image blurring by processing during the process, means for mounting a drum heater for heating a photoreceptor is used. Although the occurrence of image blur can be suppressed by heating the photoconductor,
To mount a drum heater, the diameter of the photoreceptor must be large. It has been difficult. Furthermore, the installation of the drum heater necessitates an increase in the size of the device, which significantly increases power consumption and requires a lot of time to start up the device. Was.

As described above, in order to ensure the transparency of the protective layer, the transparency of various materials constituting the protective layer to image writing light is important. Particularly, in most cases, the filler contained in the protective layer has a refractive index different from that of the binder resin used for the protective layer, and thus tends to make the protective layer itself opaque. To improve this, the film has been made transparent by reducing the particle size of the filler used as much as possible. This is because if the particle diameter is smaller than the wavelength of the writing light, light scattering by the filler is substantially eliminated and the light becomes transparent. In such an example, the protective layer becomes substantially transparent by reducing the average particle size of the metal or metal oxide contained as a filler to 0.3 μm or less (JP-A-57-30846). A method for suppressing the residual potential accumulation is disclosed. Although this method has the effect of ensuring the transparency of the protective layer, it actually reduces the effect of adding a filler to improve the wear resistance of the protective layer. To address this point, it has been changed to improve the abrasion resistance of the binder resin and improve the abrasion resistance of the protective layer, rather than improving the abrasion resistance of the filler by improving the binder resin. Certainly, inorganic photoconductors represented by the selenium photoconductive layer can be used in combination with inorganic long-life electrostatic characteristics and protective layers with high abrasion resistance to produce extremely long-life photoconductors. It has been developed. Regarding the transparency of the protective layer, even if the average particle diameter of the filler is 0.3 μm or more, transparency can be obtained by increasing the dispersibility, and the average particle diameter is 0.3 μm or less. Even so, if the filler is considerably aggregated, the transparency of the film will be reduced.

On the other hand, as described above, in recent years, there has been a shift to non-polluting organic photoconductors, and it is not an exaggeration to say that most photoconductors in the world are organic photoconductors. Has become. Under such circumstances, as a target for the development of a highly durable photoreceptor, development of a protective layer matching an organic photosensitive layer is one of the major issues.

In view of such problems, for example, Japanese Patent Application Laid-Open
JP-A-234471 and JP-A-8-314174 propose to use two types of fillers having different particle diameters or specific gravities in the outermost layer of the photoreceptor. In this case, as compared with the case where one kind of filler is used alone, the above-mentioned trade-off relationship is eased, and the design margin may be improved. However, in order to obtain the required abrasion resistance, it is necessary to fill two kinds of fillers having different particle diameters into the coating film so as to be in a state of a certain density. Membrane transparency,
The scattering of writing light was increased, and was not always satisfactory. In addition, when particles having a small particle diameter (large surface area) exist near the surface, adsorption of various substances (reactive gas and the like) to the particle surface is likely to occur, and deterioration of the photoconductor (for example, image blur) is caused. It is true that it is easy to happen. For this reason, when two types of fillers having different particle diameters are used in combination, a configuration in which the filler having a small particle size is eliminated as much as possible from the photoconductor surface side, that is, a configuration having a particle size gradient as in the present invention is adopted. Thereby, the above problem can be solved.

[0010] In addition, inorganic photoconductors used in the past have been used with positive charge regardless of the presence or absence of a protective layer. On the other hand, charge transport materials used for organic photoreceptors have been developed in both hole transport type and electron transport type, but those which have actually reached the practical level are hole transport types. For this reason, in the function-separated type photoreceptor designed to make the most of the characteristics of the OPC, negative charging occupies most of it. Some single-layer photosensitive layers and reverse-layer photosensitive layers have been developed, but are not the mainstream.

It is considered that one of the reasons why the protective layer technology developed for the inorganic photoreceptor cannot be spread horizontally to the organic photoreceptor is due to the charging polarity. That is, the charging potential of the inorganic photoconductor and that of the organic photoconductor are almost the same. At this time, in consideration of the discharging efficiency of the charger, the charging efficiency is generally higher in positive charging than in positive charging.
It is also known that, when comparing the amount of generated reactive gas and the like during positive charging and negative charging, the amount of negative charging is overwhelmingly larger. It is understood that the phenomenon of image blur is caused at least by a decrease in the surface resistance of the photoconductor, and this reduction in the surface resistance causes the low-resistance substance generated by the reactive gas to adhere to the surface of the photoconductor. It is also known to be the main cause.

In order to improve such a point, a contact-type charging system has been proposed. However, although positive data such as the fact that the ozone concentration near the charging member is lowered is disclosed, the invention is disclosed. According to the results measured by the inventors, it became clear that the amount of the low-resistance substance adhered to the surface of the photoreceptor was almost the same as when the non-contact type charging member was used. This is because although the contact type charging member is used, the voltage applied to the charging member can be reduced, but the distance between the photosensitive member and the discharger is reduced, and the airflow does not flow well, or the contact is low resistance material. This is considered to be caused by directly pressing the photoconductor against the surface of the photoconductor.

No effective means for solving the above problems at the same time has been found so far. When a filler is contained in the outermost surface layer such as a protective layer of a photoreceptor for high durability, an image is not obtained. The fact is that the effects of blurring and rise in residual potential appear strongly, and the problem of high image quality still remains. Furthermore, since it is necessary to mount a drum heater to reduce these effects, high durability of the small-diameter photoreceptor, which requires the most durability, has not been realized. In fact, it is also a major obstacle to reducing power consumption.

An organic photoreceptor has come to surpass an inorganic photoreceptor in light sensitivity, spectral sensitivity range, pollution-free property, electrostatic durability and the like. Improving mechanical durability is urgently needed, and its development has been eagerly sought in the design of highly durable machines and processes.

As a full-color image forming apparatus using an electrophotographic system, two systems are generally known. One is a single type or a single drum type, in which one electrophotographic photosensitive member is mounted in an apparatus and four color developing members are mounted. In this method, four colors (cyan, magenta, yellow, and black) are applied to a photosensitive member or a transferred member (directly transferred to output paper or temporarily transferred to an intermediate transfer member, and then transferred to paper). A toner image is formed. In this case, the charging member, the exposure member, the transfer member, the cleaning member, and the fixing member disposed around the photoreceptor can be shared, and the design is smaller and lower cost than the tandem type described later. Is possible.

On the other hand, there is another system called a tandem system or a tandem drum system. In this case, at least a plurality of electrophotographic photosensitive members are mounted in the apparatus. Generally, for one drum,
Each member of charging, exposure, development, and cleaning is arranged one by one to form one electrophotographic element, and a plurality (generally four) of these are mounted. In this method, a single color toner image is formed by one electrophotographic element, and the toner image is sequentially transferred to a transfer target to form a full color image. The first advantage of this method is that high-speed image formation is possible. This is because, as described above, toner images of each color can be produced by parallel processing. For this reason, the image forming processing time is about one-fourth the time required in the single system, and it is possible to cope with four times the high-speed printing. A second advantage is that the durability of each member provided in the electrophotographic element including the photoreceptor can be substantially increased. This is because, in the single system, each of the charging, exposure, and development processes is performed four times with one photosensitive member to form one full-color image, whereas in the tandem system, the above operation is performed once by one unit. This is because it is only performed.

However, there is also a disadvantage that the whole apparatus becomes large and the cost becomes high. Regarding the increase in the size of the entire apparatus, measures have been taken by reducing the diameter of the photoreceptor, miniaturizing the members provided around the photoreceptor, and reducing the size of one electrophotographic element. As a result, not only the miniaturization of the apparatus but also the effect of reducing the material cost have been brought about, and the cost reduction of the entire apparatus has progressed somewhat. However, with the downsizing and miniaturization of the apparatus, a new problem has arisen that the durability of each member including the photoreceptor mounted on the electrophotographic element must be increased.

Further, in tandem type image formation, since a plurality of image forming elements must simultaneously form an image, the plurality of image forming elements have almost the same characteristics both initially and after aging (repeated use). It also has a problem that it must have. The most influential in this regard is the electrostatic properties of the photoreceptor in the imaging element. If the characteristics of photoreceptors used for a plurality of image forming elements vary widely, the color balance of the output image changes, and the color reproducibility differs from the original input image, which is fatal to a full-color image forming apparatus. Problems occur.

[0019]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photoreceptor capable of forming a high-quality image which is durable and stable for repeated use. Specifically, to provide a photoreceptor that has high durability, suppresses image deterioration due to a rise in residual potential or occurrence of image blur, and can stably obtain a high-quality image even when used repeatedly for a long time. It is in. Another object of the present invention is to provide a photoreceptor having good color reproducibility even after repeated use in a tandem type image forming apparatus.

Further, by using such photoreceptors, it is not necessary to replace the photoreceptors, and it is possible to realize high-speed printing or downsizing of the apparatus due to reduction in the diameter of the photoreceptors. An object of the present invention is to provide a stable electrophotographic method, an electrophotographic apparatus, and an electrophotographic process cartridge.

[0021]

SUMMARY OF THE INVENTION The present invention relates to an electrophotographic photoreceptor comprising a photosensitive layer containing at least an organic charge generating substance and an organic charge transporting substance and a surface layer on a conductive support. Contains two or more types of fillers having different volume average particle diameters (the filler constituent material is composed of the same or different material), and the filler particle size distribution in the protective layer continuously changes from the photosensitive layer side to the surface side. An electrophotographic photoreceptor characterized in that the electrophotographic photoreceptor is configured to have a large particle size distribution gradient. The particle size distribution referred to here indicates a mixing ratio of two or more kinds of fillers having different filler particle sizes, and the same applies to the following description. Further, that the particle size distribution continuously increases means that the protective layer is composed of a single layer, and that the mixing ratio of two or more fillers in the single protective layer is continuously changed. .

The present invention also relates to an electrophotographic photoreceptor comprising at least a photosensitive layer containing an organic charge-generating substance and an organic charge-transporting substance and a protective layer on a conductive support, wherein the surface layer comprises at least two layers. And each protective layer contains two or more types of fillers having different volume average particle sizes (the filler constituent material is composed of the same or different material), and the filler particle size distribution in the protective layer is An electrophotographic photoreceptor characterized in that the size of the photoreceptor increases in order from the photosensitive layer side to the surface side. In addition, that the particle size distribution sequentially increases means that the protective layer is composed of a plurality of layers, and that the mixing ratio of two or more fillers in the plurality of protective layers changes stepwise.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION In an electrophotographic photoreceptor having a photosensitive layer containing at least an organic charge generating substance and an organic charge transporting substance and a protective layer on a conductive support, it is possible to improve the abrasion resistance and improve the residual property. The three points of reducing potential, improving abrasion resistance and suppressing image blur, and improving abrasion resistance and improving resolution tend to be in a trade-off relationship. However, by using two kinds of fillers having different particle diameters in the protective layer and having a configuration in which the filler particle size distribution is inclined (a configuration in which the particle size distribution is continuously increased from the support side to the surface side), It has been found that the above three problems can be solved at the same time, and a photoreceptor that can form a high-quality image that is durable and stable for repeated use can be designed. In addition, a stable high-quality image can be formed at high speed even in repeated use. Possible electrophotographic methods, electrophotographic devices, and electrophotographic process cartridges can be designed.

Further, at least two or more protective layers having a layered constitution are used, and two or more kinds of fillers having different particle diameters are used. On the outermost surface side, a filler having a large particle diameter is used. By using a filler having a small particle diameter, the above-mentioned problems can be solved at the same time, and a photoreceptor capable of forming a high-quality image with high durability and stable for repeated use can be designed. In addition, it is possible to design an electrophotographic method, an electrophotographic apparatus, and an electrophotographic process cartridge capable of forming a stable high-quality image at high speed.

Further, at least two or more protective layers each having a laminated structure are used, and two or more kinds of fillers having different particle diameters are used.
By using a filler having a large particle size on the outermost surface side and using a particle having a small filler particle size on the photosensitive layer side, a change in the electrostatic characteristics of the photoreceptor between a plurality of image forming elements and abrasion are caused. The variation in the amount is reduced,
It becomes possible to design a tandem-type full-color image forming apparatus having good color reproducibility even by repeated use.

Hereinafter, an electrophotographic photosensitive member used in the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration example of an electrophotographic photoreceptor of the present invention, in which a single-layer photosensitive layer 2 having a charge generation material and a charge transport material as main components is provided on a conductive support 1. Further, a protective layer 3 is provided on the surface of the photosensitive layer. In this case, the protective layer 3 has two different average particle sizes.
At least one kind of filler is contained, and the filler particle size distribution is continuously increased from the support side toward the surface side (has a particle size distribution gradient).

FIG. 2 is a cross-sectional view showing another example of the structure of the electrophotographic photosensitive member of the present invention, in which a charge generating layer 4 mainly composed of a charge generating material and a charge transport It has a configuration in which a charge transport layer 5 mainly composed of a material is laminated, and a protective layer 3 is further provided on the charge transport layer.
In this case, the protective layer 3 contains two types of fillers having different average particle sizes, and has a configuration in which the filler particle size distribution is continuously increased from the support side to the surface side (has a particle size distribution gradient). .

FIG. 3 is a cross-sectional view showing an example of the structure of the electrophotographic photoreceptor of the present invention, in which a single-layer photosensitive layer 2 containing a charge generation material and a charge transport material as main components on a conductive support 1. And a plurality of protective layers 3 having different filler particle size distributions are provided on the surface of the photosensitive layer. In this case, the protective layer 3 contains two types of fillers having different average particle sizes,
It has a configuration in which the filler particle size distribution is gradually increased from the support side to the surface side.

FIG. 4 is a cross-sectional view showing another example of the structure of the electrophotographic photoreceptor of the present invention, in which a charge generating layer 4 mainly composed of a charge generating material and a charge transport material are provided on a conductive support 1. It has a configuration in which a charge transport layer 5 mainly composed of a material is laminated, and a plurality of protective layers 3 having different filler particle size distributions are provided on the surface of the charge transport layer. In this case, the protective layer 3
Contains a filler having a different average particle size, and has a configuration in which the filler particle size distribution is gradually increased from the support side toward the surface side.

In the configuration shown in FIGS. 1 to 4,
The two types of fillers having different filler particle size distributions may be made of the same material (material) or different materials. When it is not desired to largely change the characteristics as the protective layer bulk, by using the same material, stable characteristics can be obtained. On the other hand, when it is desired to set the resistance of the bulk of the protective layer to be low, if a component having a low resistance is contained on the surface side, image blur is likely to occur. It is not preferable to contain them. Therefore, by increasing the specific resistance of the filler having a large particle diameter and decreasing the specific resistance of the filler having a small particle diameter, the gradient of the particle size distribution is formed, and at the same time, the gradient of the specific resistance is added. The effect of the above is made more remarkable.

The conductive support 1 has a volume resistance of 10
Those exhibiting a conductivity of ¹⁰ Ωcm or less, for example, aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum and other metals, tin oxide, metal oxides such as indium oxide, by evaporation or sputtering, Film or cylindrical plastic, coated on paper, or aluminum, aluminum alloy, nickel,
Plates made of stainless steel or the like and pipes made by extruding or drawing them and then surface-treated such as cutting, super-finishing, and polishing 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 1.

Among these, a cylindrical support made of aluminum, which can be easily subjected to the anodic oxide film treatment, can be most preferably used. The aluminum referred to here includes both pure aluminum and aluminum alloy. Specifically, JIS1000 series,
Aluminum or aluminum alloys in the 3000s and 6000s are most suitable. The anodized film is obtained by anodizing various metals and various alloys in an electrolyte solution. Among them, a film called alumite obtained by anodizing aluminum or an aluminum alloy in an electrolyte solution is a photoconductor used in the present invention. Is most suitable for In particular, they are excellent in preventing point defects (black spots, background stains) generated when used in reversal development (negative / positive development).

The anodic oxidation treatment includes chromic acid, sulfuric acid, oxalic acid,
The reaction is performed in an acidic bath such as phosphoric acid, boric acid, and sulfamic acid. Of these, treatment with a sulfuric acid bath is most suitable. For example, sulfuric acid concentration: 10 to 20%, bath temperature:
5 to 25 ° C, current density: 1 to 4 A / dm ² , electrolytic voltage:
The processing is performed within a range of 5 to 30 V and a processing time of about 5 to 60 minutes, but is not limited thereto. Since the anodic oxide film thus produced is porous and has high insulation properties, the surface is very unstable. For this reason, there is a temporal change after fabrication, and the physical property value of the anodic oxide film tends to change. In order to avoid this, it is desirable to further seal the anodic oxide film. Examples of the sealing treatment include a method of immersing the anodic oxide film in an aqueous solution containing nickel fluoride and nickel acetate, a method of immersing the anodic oxide film in boiling water, and a method of performing treatment with pressurized steam. Among them, a method of immersing in an aqueous solution containing nickel acetate is most preferable. Subsequent to the sealing treatment, a cleaning treatment of the anodic oxide film is performed. The main purpose of this is to remove excess metal salts and the like attached by the sealing treatment.
If this remains on the surface of the support (anodic oxide film) excessively, it not only adversely affects the quality of the coating film formed thereon, but also generally causes a low resistance component to remain. It will also be the cause. The washing may be a single washing with pure water, but usually another stage of washing is performed. At this time, it is preferable that the final cleaning liquid is as clean (deionized) as possible. In addition, it is desirable to perform physical rubbing cleaning with a contact member in one of the other cleaning steps. The thickness of the anodic oxide film formed as described above is desirably about 5 to 15 μm. If the thickness is too thin, the barrier effect as an anodic oxide film is not sufficient.If the thickness is too thick, the time constant of the electrode becomes too large, and the generation of residual potential and the response of the photoreceptor decrease. May be.

In addition to the above, a support obtained by dispersing a conductive powder on a suitable binder resin on the above support and applying the same can also be used as the conductive support 1 of the present invention. As the conductive powder, carbon black, acetylene black, aluminum, nickel, iron, nichrome, copper, zinc,
Metal powder such as silver, or metal oxide powder such as conductive tin oxide and ITO can be used. Further, the binder resin used simultaneously, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer,
Styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral Thermoplastic, thermosetting or photo-curable resins such as polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin and alkyd resin. Can be 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) or the like containing the above-mentioned 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 1 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 4 and the charge transport layer 5 will be described first.

The charge generation layer 4 is a layer containing a charge generation substance as a main component. For the charge generation layer 4, 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 polycycles. 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.

Among them, azo pigments and / or phthalocyanine pigments are effectively used. In particular, an azo pigment represented by the following structural formula (I) and a diffraction peak (± 0.2 °) of titanyl phthalocyanine, particularly CuKα, with a characteristic X-ray (wavelength 1.542 °) at a Bragg angle 2θ of at least 27.2. Titanyl phthalocyanine having the maximum diffraction peak at ゜ can be effectively used.

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

Embedded image (II) In the formula, R ₂₀₃ represents a hydrogen atom, an alkyl group such as a methyl group or an ethyl group, or an aryl group such as a phenyl group. R
_{204, R 205, R 206,} R 207, R 20 8 each represents a hydrogen atom, a nitro group, a cyano group, fluorine, chlorine, bromine, a halogen atom such as iodine, trifluoromethyl group, methyl group, such as ethyl Represents an alkyl group, a methoxy group, an alkoxy group such as an ethoxy group, a dialkylamino group, or a hydroxyl group, and Z represents an atom necessary for forming a substituted or unsubstituted aromatic carbocyclic ring or a substituted or unsubstituted aromatic heterocyclic ring. Represents a group.

In particular, the asymmetric azo pigment having a structure in which Cp ₁ and Cp ₂ are different from each other often has better photosensitivity than a target azo pigment in which Cp ₁ and Cp ₂ have the same structure. It can cope with the reduction of diameter and the speed of the use process, and is used effectively.

The diffraction peak at the Bragg angle 2θ (±
Among titanyl phthalocyanines having a maximum diffraction peak at 27.2 ° as 0.2 °), titanyl phthalocyanines having a peak at 7.3 ° as the lowest angle (JP-A-200
Described in Japanese Patent Application Laid-Open No. 1-18771) is highly sensitive, has a small decrease in chargeability upon repeated use, and can be used particularly effectively.

The charge generation layer 4 is dispersed in a suitable solvent together with a binder resin if necessary by using a ball mill, an attritor, a sand mill, ultrasonic waves, or the like, applied to a conductive support, and dried. It is formed by doing.

If necessary, the binder resin used for the charge generation layer 4 includes polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicon 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. As a method of applying the coating liquid, a method such as a dip coating method, a spray coat, a beat coat, a nozzle coat, a spinner coat, and a ring coat can be used.

The thickness of the charge generation layer 4 is 0.01 to 5 μm.
m is appropriate, and preferably 0.1 to 2 μm.

The charge transporting layer 5 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. If necessary, a plasticizer, a leveling agent, an antioxidant and the like can be added.

The charge transport material includes a hole transport material and an electron transport material. Examples of the charge transport 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
And other known materials such as styryl anthracene 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. Further, the thickness of the charge transport layer is preferably 25 μm or less from the viewpoint of resolution and response. Although the lower limit varies depending on the system used (especially the charged potential, etc.), the lower limit is preferably 5 μm or more.

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

In the photoreceptor of the present invention, a plasticizer or a leveling agent may be added to the charge transport layer 5. As the plasticizer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount of the plasticizer is suitably about 0 to 30% by weight based on the binder resin. Examples of the leveling agent include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in a side chain. 1% by weight is suitable.

Next, the case where the photosensitive layer has a single-layer structure will be described. A photoconductor in which the above-described charge generating substance is dispersed in a binder resin can be used. The single-layer photosensitive layer can be formed by dissolving or dispersing a charge generating substance, a charge transporting substance, and a binder resin in a suitable solvent, and applying and drying the same.
Further, this photosensitive layer may be of a function-separated type in which the above-described charge transporting material is added, and can be used favorably. If necessary, a plasticizer, a leveling agent, an antioxidant and the like can be added.

As the binder resin, in addition to using the binder resin described above for the charge transport layer 5 as it is, a mixture of the binder resin described for the charge generation layer 4 may be used. Of course, the above-mentioned polymer charge transport materials can also be used favorably. The amount of the charge generating substance is 5 to 40 with respect to 100 parts by weight of the binder resin.
The amount of the charge transporting material is preferably 0 to 190 parts by weight, more preferably 50 to 150 parts by weight. The single-layer photosensitive layer is formed by dip coating or spraying a coating liquid obtained by dispersing a charge generating substance and a binder resin together with a charge transporting substance, if necessary, using a solvent such as tetrahydrofuran, dioxane, dichloroethane, or cyclohexane with a dispersing machine. It can be formed by coating with a coat, a bead coat, or the like. The thickness of the single-layer photosensitive layer is suitably about 5 to 25 μm.

In the photoreceptor of the present invention, an undercoat layer can be provided between the conductive support 1 and the photosensitive layer.
The undercoat layer generally contains a resin as a main component, but considering that these resins are coated on the photosensitive layer with a solvent,
It is desirable that the resin has high solvent resistance to general organic solvents. Examples of such a resin include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, copolymer-soluble nylons, alcohol-soluble resins such as methoxymethylated nylon, polyurethane, melamine resins, phenol resins, alkyd-melamine resins, and epoxy resins. Curable resins that form a three-dimensional network structure, such as resins, are exemplified. Further, a fine powder pigment of a metal oxide exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moiré and reduce residual potential.

These undercoat layers can be formed by using an appropriate solvent and a coating method as in the above-mentioned photosensitive layer. Further, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention. In addition, the undercoat layer of the present invention includes Al ₂
O ₃ provided by anodic oxidation, organic substances such as polyparaxylylene (parylene), SiO ₂ , SnO ₂ , TiO _2
2 , an inorganic material such as ITO, CeO ₂ or the like provided by a vacuum thin film forming method can also be used favorably. In addition, known materials can be used. The thickness of the undercoat layer is 0 to 5 μm
Is appropriate.

In the photosensitive member of the present invention, a protective layer 3 is provided on the photosensitive layer for the purpose of protecting the photosensitive layer. Protective layer 3
Is composed so that two types of fillers having different average particle sizes are contained, and the filler particle size distribution continuously increases from the support side to the surface side. As a result, it is possible to achieve both improvement of the abrasion resistance of the photoreceptor surface, reduction of residual potential, transparency, and reduction of image blur.

In another example, the protective layer 3 is composed of a plurality of layers of two or more layers, contains two types of fillers having different average particle diameters, and has a filler particle size distribution from the support side to the surface side. It is configured to be large. As a result, it is possible to achieve both improvement of the abrasion resistance of the photoreceptor surface, reduction of residual potential, transparency, and reduction of image blur.

The filler concentration in the protective layer varies depending on the type of filler used and the electrophotographic process conditions using the photoreceptor. However, at the outermost layer side of the protective layer, the ratio of the filler to the total solid content is 50% by weight or less. , Preferably about 30% by weight or less. On the most photosensitive layer side of the protective layer, 30% by weight or less, preferably about 10% by weight or less is good.

The filler having a larger average particle diameter among the fillers used has a volume average particle diameter of 0.1 μm to 0.1 μm.
A range of 2 μm is well used, preferably 0.3 μm
１1 μm. In this case, if the average particle size is too small, the abrasion resistance is not sufficiently exhibited, and if the average particle size is too large, the surface properties of the coating film deteriorate, or the coating film itself cannot be formed.

The average particle size of the filler in the present invention is a volume average particle size unless otherwise specified, and is determined by an ultracentrifugal automatic particle size distribution analyzer: CAPA-700 (manufactured by Horiba, Ltd.). It is. At this time, 5 of the cumulative distribution
It is calculated as a particle diameter (Median diameter) corresponding to 0%. It is important that the standard deviation of each particle measured at the same time is 1 μm or less. If the value of the standard deviation is larger than this, the particle size distribution may be too wide and the effect of the present invention may not be obtained remarkably.

The mixing ratio of the fillers having different average particle diameters is not particularly limited, but in the outermost layer of the protective layer, the ratio of the filler having a large particle diameter is preferably 50% or more of all the fillers. Is preferably 70% or more.

The material used for the protective layer 3 is ABS
Resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide,
Polyacrylate, polyallyl sulfone, polybutylene, polybutylene terephthalate, polycarbonate,
Polyarylate, polyether sulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS
Resin, butadiene-styrene copolymer, polyurethane,
Resins such as polyvinyl chloride, polyvinylidene chloride, and epoxy resin are exemplified. Among them, polycarbonate or polyarylate can be most preferably used.

Among the filler materials used in the protective layer of the photoreceptor, organic filler materials include fluororesin powders such as polytetrafluoroethylene, silicone resin powders, a-carbon powders and the like. Examples of inorganic filler materials include copper, tin, aluminum, metal powders such as indium, silica, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, and antimony. Examples of such materials include tin oxide, metal oxides such as indium oxide doped with tin, and inorganic materials such as potassium titanate. Particularly, from the viewpoint of the hardness of the filler, it is advantageous to use an inorganic material among them. In particular, silica, titanium oxide, and alumina can be used effectively.

The pH of the filler, which is one of the constituent elements of the present invention, greatly affects the resolution and the dispersibility of the filler. As one of the reasons, it is considered that hydrochloric acid or the like remains in the filler, particularly the metal oxide during the production. If the remaining amount is large, the occurrence of image blur is inevitable,
It may also affect the dispersibility of the filler, depending on the amount remaining.

Another reason is that the chargeability on the surface of the filler, especially the metal oxide, is different. Normally, particles dispersed in a liquid are positively or negatively charged, and ions with the opposite charge gather to keep it electrically neutral, where an electric double layer is formed. The dispersion state of the particles is stabilized. As the distance from the particle increases, its potential (zeta potential) gradually decreases, and the potential of a region sufficiently far from the particle and electrically neutral becomes zero. Therefore, the stability is increased by increasing the absolute value of the zeta potential to increase the repulsive force of the particles, and the particles tend to aggregate and become unstable as the value approaches zero. On the other hand, the zeta potential fluctuates greatly depending on the pH value of the system, and at a certain pH value, the potential becomes zero, and has an isoelectric point. Therefore, the dispersion system is stabilized by increasing the absolute value of the zeta potential as far as possible from the isoelectric point of the system.

In the constitution of the present invention, the filler having a pH at the above isoelectric point of at least 5 is preferable from the viewpoint of suppressing image blur, and the more basic the filler, the higher the effect. It was confirmed that there was a tendency. The filler having a high pH at the isoelectric point and exhibiting a basic property has a higher zeta potential when the system is acidic, so that the dispersibility and the stability thereof are improved.

Here, the pH of the filler in the present invention is
Indicates the pH value at the isoelectric point from the zeta potential.
At this time, the zeta potential was measured with a laser zeta potentiometer manufactured by Otsuka Electronics Co., Ltd.

Further, as a filler which is less likely to cause image blur, a filler having a high electrical insulation property (a specific resistance of 10 ¹⁰
Ω · cm or more), and those having a filler pH of 5 or more and those having a filler dielectric constant of 5 or more can be particularly effectively used. In addition, a filler having a pH of 5 or more or a filler having a dielectric constant of 5 or more may be used alone. It is also possible to use a mixture of two or more kinds of fillers having a dielectric constant of 5 or less and fillers having a dielectric constant of 5 or more. Among these fillers, α-alumina, which has high insulation properties, high thermal stability, and high wear resistance, has a hexagonal close-packed structure, from the viewpoint of suppressing image blur and improving wear resistance Particularly useful.

The specific resistance of the filler used in the present invention is defined as follows. Powders such as fillers
Since the specific resistance value differs depending on the filling rate, it is necessary to measure under a certain condition. In the present invention, the method disclosed in
94049 (FIG. 1), JP-A-5-113688
The specific resistance value of the filler was measured using an apparatus having the same configuration as that of the measuring apparatus shown in Japanese Patent Application Laid-Open Publication No. (FIG. 1), and this value was used. In the measuring device, the electrode area is 4.0 cm ² . Before measurement, apply a load of 4 kg to one electrode for one minute,
The amount of the sample is adjusted so that the distance between the electrodes becomes 4 mm. At the time of the measurement, the measurement is performed under the load state of the weight (1 kg) of the upper electrode, and the applied voltage is measured at 100V. 10 ⁶ Ω
cm or more is HIGH RESISTANCE
METER (Yokogawa Hewlett-Packard), digital multimeter (Fluke)
Was measured by The specific resistance value thus obtained is defined as the specific resistance value according to the present invention.

The dielectric constant of the filler was measured as follows. After applying a load using the same cell as the measurement of the specific resistance as described above, the capacitance was measured, and the dielectric constant was obtained from the capacitance. The capacitance was measured using a dielectric loss meter (Ando Electric).

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. A 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, a titanate-based coupling agent, an aluminum-based coupling agent, a zircoaluminate-based coupling agent, a higher fatty acid, or the like, or a mixing treatment thereof with a silane coupling agent, Al ₂ O ₃ , T
iO ₂ , ZrO ₂ , silicone, aluminum stearate or the like, or a mixture thereof is more preferable from the viewpoint of filler dispersibility and image blur. The treatment with the silane coupling agent has a strong effect on image blur, but the effect of mixing the surface treatment agent and the silane coupling agent may be suppressed in some cases. Although the surface treatment amount varies depending on the average primary particle size of the filler used, 3 to 30 wt% is suitable, and 5 to 20 w
t% is more preferred. 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. These filler materials are used alone or in combination of two or more. The surface treatment amount of the filler is defined by the weight ratio of the used surface treatment agent to the filler amount as described above.

These filler materials can be dispersed by using an appropriate disperser. Further, the filler used in terms of the transmittance of the protective layer is dispersed to the primary particle level,
It is preferable that the number of aggregates is small.

As a method for forming a protective layer having a multilayer structure having a graded particle size distribution gradient, an ordinary coating method is employed. Among them, the spray method is an effective means, and the following two methods can be cited as optimal methods. One is a method of sequentially laminating a plurality of coating liquids for a protective layer having different filler ratios by spraying after the touch-drying of the lower layer is completed.
In this case, it is desirable to prepare spray heads by the number of coating liquids and perform coating continuously. The other method is to prepare a spray head for each filler to be used, prepare a dispersion of each filler alone, change the discharge amount from the photosensitive layer side to the surface side, and provide a particle size distribution. Can be

As a method for forming a protective layer having a single-layer structure having a continuous particle size distribution, an ordinary coating method is employed. Among them, the spray method is an effective means, and the following two methods can be cited as optimal methods. One is a method in which a plurality of coating liquids for protective layers having different filler ratios are sequentially laminated by a spray method before the lower layer is not dried. In this case, it is desirable to prepare spray heads by the number of coating liquids and perform coating continuously. The other method is to prepare a spray head for each filler to be used, prepare a dispersion of each filler alone, change the discharge amount from the photosensitive layer side to the surface side, and provide a particle size distribution. Can be

The protective layer 3 may contain a charge transporting substance for reducing the residual potential and improving the response. As the charge transport substance, the materials described in the description of the charge transport layer can be used. When a low-molecular charge transport material is used as the charge transport material, a concentration gradient in the protective layer may be provided. It is an effective means to reduce the concentration on the surface side in order to improve abrasion resistance. Here, the concentration refers to the ratio of the weight of the low-molecular charge transporting substance to the total weight of all the materials constituting the protective layer, and the concentration gradient is such that the concentration decreases on the surface side at the above weight ratio. Indicates that

For the protective layer, a polymer charge transporting material having both a function as a charge transporting material and a function as a binder resin is preferably used. The protective layer composed of such a polymer charge transport material has excellent abrasion resistance. As the polymer charge transporting substance, known materials can be used, and particularly, a polycarbonate containing a triarylamine structure in a main chain and / or a side chain is preferably used. Among them,
Polymer charge transport materials represented by the formulas (III) to (XII) are favorably used. These are exemplified below, and specific examples are shown below.

Formula (III)

Embedded image In the formula, R ₁ , R ₂ , and R ₃ are each independently a substituted or unsubstituted alkyl group or a halogen atom, R ₄ is a hydrogen atom or a substituted or unsubstituted alkyl group, and R ₅ and R ₆ are substituted or unsubstituted. A substituted aryl group, o, p, and q each independently represent an integer of 0 to 4; k and j each represent a composition;
≦ k ≦ 1, 0 ≦ j ≦ 0.9, n represents the number of repeating units and is an integer of 5 to 5000. X represents an aliphatic divalent group, a cycloaliphatic divalent group, or a divalent group represented by the following general formula.

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, m is an integer of 0 to 4, Y is a single bond, a linear C1-12, branched or cyclic alkylene group, -O -, - S -, - SO -, - SO 2 - , -CO
-, -CO-O-Z-O-CO- (where Z is an aliphatic 2
Represents a valence group. ) Or

Embedded image(Where a is an integer of 1 to 20, b is an integer of 1 to 2,000
Number, R₁₀₃, R₁₀₄Is a substituted or unsubstituted alkyl
Represents a group or an aryl group. ). Where R ₁₀₁
And R₁₀₂, R₁₀₃And R₁₀₄Are the same
May be different.

Formula (IV)

Embedded image In the formula, R ₇ and R ₈ are a substituted or unsubstituted aryl group,
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 (III).

Equation (V)

Embedded imageWhere R₉, R₁₀Is a substituted or unsubstituted aryl
Group, Ar₄, Ar₅, Ar ₆Are the same or different allylenes
Represents a group. X, k, j and n are the same as in the case of the formula (III).
Is the same.

Formula (VI)

Embedded image In the formula, R ₁₁ and R ₁₂ represent a substituted or unsubstituted aryl group, Ar ₇ , Ar ₈ , and Ar ₉ represent the same or different arylene groups, and p represents an integer of 1 to 5. X, k, j and n are
The same as in the case of the formula (III).

Formula (VII)

Embedded image In the formula, R ₁₃ and R ₁₄ are substituted or unsubstituted aryl groups, Ar ₁₀ , Ar ₁₁ , and Ar ₁₂ are the same or different arylene groups, X ₁ and X ₂ are substituted or unsubstituted ethylene groups, or substituted or unsubstituted ethylene groups. Represents a substituted vinylene group. X,
k, j and n are the same as in the case of the formula (III).

Formula (VIII)

Embedded imageWhere R_Fifteen, R₁₆, R₁₇, R₁₈Is replaced or
Unsubstituted aryl group, Ar₁₃, Ar₁₄, Ar_Fifteen,
Ar₁₆Are the same or different arylene groups, Y₁, Y ₂, Y
₃Is a single bond, a substituted or unsubstituted alkylene group,
Or an unsubstituted cycloalkylene group,
Substituted alkylene ether group, oxygen atom, sulfur atom,
It represents a nylene group and may be the same or different. X,
k, j and n are the same as in the case of the formula (III).

(IX)

Embedded imageWhere R₁₉, R₂₀Is a hydrogen atom, substituted or unsubstituted
R represents an aryl group ₁₉And R₂₀Forms a ring
You may. Ar₁₇, Ar₁₈, Ar₁₉Are the same or different
Represents an arylene group. X, k, j and n are (II
I) Same as equation.

Equation (X)

Embedded image In the formula, R ₂₁ is a substituted or unsubstituted aryl group, Ar
_{20, Ar 21, Ar 2 2} , Ar 23 independently represent an arylene group. X, k, j and n are the same as in the case of the formula (III).

Formula (XI)

Embedded image In the formula, R ₂₂ , R _23, R ₂₄ , and R ₂₅ represent a substituted or unsubstituted aryl group, 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 (III).

Formula (XII)

Embedded image In the formula, R ₂₆ and R ₂₇ 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 (III).

As the polymer charge transporting material used for the protective layer, in addition to the above-described polymer charge transporting material, when the protective layer is formed, the film may be formed in a monomer or oligomer having an electron donating group. A polymer having a two-dimensional or three-dimensional crosslinked structure is finally included by a curing reaction or a crosslinking reaction performed later.

The protective layer composed of the polymer having an electron donating group or the polymer having a crosslinked structure has excellent abrasion resistance. Normally, in the electrophotographic process, the charged potential (the unexposed portion potential) is constant, so if the surface layer of the photoreceptor is worn by repeated use,
The electric field intensity applied to the photoconductor increases accordingly. As the electric field strength increases, the frequency of occurrence of background contamination increases. Therefore, the high wear resistance of the photoconductor is advantageous for background contamination. The protective layer composed of the polymer having an electron donating group is excellent in film-forming properties because it is a polymer compound itself, and has a higher density of charge transport sites than the protective layer composed of a low molecular weight dispersed polymer. And has an excellent charge transporting ability. Therefore, a high-speed response can be expected for a photoreceptor having a protective layer using a polymer charge transport material.

Other polymers having an electron donating group include copolymers of known monomers, block polymers, graft polymers, star polymers, and, for example,
-109406, JP-A-2000-206723
It is also possible to use a crosslinked polymer having an electron donating group as disclosed in JP-A-2001-34001 and JP-A-2001-34001.

In the photoreceptor of the present invention, an intermediate layer can be provided between the photosensitive layer and the protective layer.
Generally, a binder resin is used as a main component. These resins include polyamide, alcohol-soluble nylon,
Water-soluble polyvinyl butyral, polyvinyl butyral,
Polyvinyl alcohol and the like. As a method for forming the intermediate layer, a normal coating method is employed as described above.
The thickness of the intermediate layer is suitably about 0.05 to 2 μm.

In the present invention, each layer is provided with an antioxidant, a plasticizer, a lubricant, an ultraviolet absorber, a low molecular weight compound, for the purpose of improving environmental resistance, in particular, for preventing a decrease in sensitivity and a rise in residual potential. Charge transport materials and leveling agents can be added. Representative materials of these compounds are described below.

Examples of antioxidants that can be added to each layer include phenolic compounds, paraphenylenediamines,
Hydroquinones, organic sulfur compounds, organic phosphorus compounds and the like can be mentioned.

Examples of the plasticizer that can be added to each layer include a phosphate ester plasticizer, a phthalate ester plasticizer, an aromatic carboxylate ester plasticizer, an aliphatic dibasic ester plasticizer, a fatty acid ester derivative, and an oxyacid. Ester plasticizer, epoxy plasticizer, dihydric alcohol ester plasticizer, chlorine-containing plasticizer, polyester plasticizer, sulfonic acid derivative, citric acid derivative, 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:
Examples include hydrocarbon compounds, fatty acid compounds, fatty acid amide compounds, ester compounds, alcohol compounds, metal soaps, natural waxes, silicone compounds, and fluorine compounds.

Examples of the ultraviolet absorber which can be added to each layer include benzophenone, salicylate, benzotriazole, cyanoacrylate, quencher (metal complex salt) and HALS (hindered amine) compounds.

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 process and the electrophotographic apparatus of the present invention, and the following modified examples also belong to the category of the present invention.

In FIG. 5, the photoreceptor 6 is provided with a plurality of protective layers having at least a particle size distribution of a filler having an average particle size different from that of the photosensitive layer on a conductive support. Alternatively, the photoreceptor 1 is provided with a protective layer having a gradient of a mixing ratio of at least a filler having a different average particle diameter from the photosensitive layer on a conductive support. Although the photoconductor 6 has a drum shape, it may have a sheet shape or an endless belt shape. As the charging member 8, the pre-transfer charger 12, and the pre-cleaning charger 17, known means such as a corotron, a scorotron, a solid state charger (solid state charger), and a charging roller are used. The charging member is preferably used in contact with or close to the photoconductor.

The contact-type charging member mentioned here is of a type in which the surface of the charging member comes into contact with the surface of the photoreceptor, and includes a charging roller, a charging blade, and a charging brush. Among them, a charging roller and a charging brush are preferably used.

The charging member disposed close to the charging member is of a type which is disposed in a non-contact state so as to have a gap (gap) of 200 μm or less between the surface of the photosensitive member and the surface of the charging member. It is distinguished from known chargers represented by corotron and scorotron based on the distance of the gap. The charging member disposed in the vicinity used in the present invention may have any shape as long as it has a mechanism capable of appropriately controlling the gap with the surface of the photoreceptor. For example, the rotation axis of the photoreceptor and the rotation axis of the charging member may be mechanically fixed so as to have an appropriate gap. Among them, using a charging member in the shape of a charging roller, disposing a gap forming member at both ends of the non-image forming portion of the charging member, bringing only this portion into contact with the photoconductor surface, and disposing the image forming region in a non-contact manner, Alternatively, a method in which the gap forming member at both ends of the photoreceptor non-image forming portion is disposed, and only this portion is brought into contact with the surface of the charging member, and the image forming region is disposed in a non-contact manner, stably stabilizes the gap by a simple method. It is a method that can be maintained. In particular, Japanese Patent Application Nos. 13-212448 and 13-2264.
The method described in No. 32 can be used favorably. FIG. 9 shows an example of a proximity charging mechanism in which a gap forming member is arranged on the charging member side.

Further, when charging the photosensitive member with the charging member, the charging member is charged by an electric field in which an AC component is superimposed on a DC component, whereby charging unevenness can be reduced and effective. It is.

As the transfer means, generally, the above-mentioned charger can be used, but an apparatus using both a transfer charger and a separation charger is effective. Light sources such as the image exposure unit 10 and the static elimination lamp 7 include a fluorescent lamp, a tungsten lamp,
A general light-emitting material such as a halogen lamp, a mercury lamp, a sodium lamp, a light-emitting diode (LED), a semiconductor laser (LD), and electroluminescence (EL) 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.

Such a light source or the like is provided with a process such as a transfer process, a charge removal process, a cleaning process, or a pre-exposure process using light irradiation in addition to the process shown in FIG. You.

The toner developed on the photosensitive member 6 by the developing unit 11 is transferred to the transfer paper 14, but not all of the toner is transferred, and toner remaining on the photosensitive member 6 is generated. Such a toner is supplied to the fur brush 18
And is removed from the photoreceptor by the blade. 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.

When the electrophotographic photosensitive member is positively (negatively) charged and subjected to image exposure, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. If this is developed with toner of negative (positive) polarity (electrostatic detection fine particles), a positive image can be obtained, and if it is developed with toner of positive (negative) polarity, a negative image can be obtained. A known method is applied to such a developing unit.
In addition, a known method is 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, at least a plurality of protective layers having a particle size distribution of fillers having different average particle sizes from the photosensitive layer, or a protective layer having a mixing ratio gradient of fillers having different average particle sizes. It is provided.
Driven by the drive rollers 22a and 22b, charging by a charging roller (charger) 23, image exposure by a light source 24, development (not shown), transfer charger (charger) 2
5, the pre-cleaning exposure by the light source 26,
Cleaning by the brush 27 and static elimination by the light source 28 are repeatedly performed. In FIG. 6, the photoreceptor 21 (in this case, of course, the support is translucent) is irradiated with light for pre-cleaning exposure from the support side.

The above-described electrophotographic process is an example of the embodiment of the present invention, and other embodiments are of course possible. For example, although the pre-cleaning exposure is performed from the support side in FIG. 6, the exposure may be performed from the photosensitive layer side, or the image exposure and the irradiation of the charge removing light 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 illustrated, but in addition, pre-transfer exposure, pre-exposure of image exposure, and other known light irradiation steps are provided, and the photoconductor is irradiated with light. Irradiation can also be performed.

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 photoconductor, and further includes a charging unit, an exposing unit, a developing unit, a transferring unit, a cleaning unit, and a discharging unit.
Devices (parts). Although there are many shapes and the like of the process cartridge, a general example is shown in FIG. The photoreceptor 33 is provided on the conductive support with at least a plurality of protective layers having a particle size distribution of fillers having different average particle diameters from the photosensitive layer or a protective layer having a mixture ratio gradient of fillers having different average particle diameters. Become.

FIG. 10 is a schematic diagram for explaining a tandem-type full-color electrophotographic apparatus of the present invention, and the following modified examples also belong to the category of the present invention. In FIG. 10, reference numerals 101C, 101M, 10
Reference numerals 1Y and 101K denote drum-shaped photoconductors. The photoconductors 101C, 101M, 101Y and 101K rotate in the direction of the arrow in FIG. 1
04C, 104M, 104Y, 104K and cleaning members 105C, 105M, 105Y, 105K are arranged. Charging members 102C, 102M, 102Y, 1
02K is a charging member that constitutes a charging device for uniformly charging the surface of the photoconductor. This charging member 102C, 1
02M, 102Y, 102K and developing members 104C, 10C
Laser light 103C, 103M, 10 from an exposure member (not shown) is provided on the surface of the photoconductor between 4M, 104Y, and 104K.
3Y and 103K are irradiated, and the photoconductors 101C and 101K are irradiated.
An electrostatic latent image is formed on M, 101Y, and 101K. Then, such photoconductors 101C and 10C
Four image forming elements 106C, 106M, 106Y, and 106K centering on 1M, 101Y, and 101K are arranged side by side along a transfer conveyance belt 110 that is a transfer material conveyance unit. The transfer conveyance belt 110 is a developing member 1 of each of the image forming units 106C, 106M, 106Y and 106K.
04C, 104M, 104Y, 104K and the cleaning members 105C, 105M, 105Y, 105K are in contact with the photoconductors 101C, 101M, 101Y, 101K, and on the surface (rear surface) of the transfer / conveying belt 110 that is on the backside of the photoconductor side. Are provided with transfer brushes 111C, 111M, 111Y and 111K for applying a transfer bias. Each image forming element 106C, 106M, 106
Y and 106K differ in the color of the toner inside the developing device, and the black toner image forming charging member 102 according to the present invention.
Only the DC component is applied to K, and the alternating electric field in which the AC component is superimposed on the DC component is applied to the non-black toner image charging members 102C, 102M, and 102Y, and all other components have the same configuration. .

In the color electrophotographic apparatus having the structure shown in FIG. 10, the image forming operation is performed as follows. First, each image forming element 106C, 106M, 106Y, 1
06K, the photoconductors 101C, 101M, 101
Charging members 102C, 102M, 102Y, 102 whose Y and 101K rotate in the direction of the arrow (the direction of rotation with the photoconductor).
Charged by K, and then the laser beam 103C,
By 103M, 103Y and 103K, an electrostatic latent image corresponding to the image of each color to be created is formed. Next, the developing member 1
The toner images are formed by developing the latent images by using 04C, 104M, 104Y, and 104K. Developing members 104C, 10
4M, 104Y, and 104K are C (cyan),
A developing member that develops with M (magenta), Y (yellow), and K (black) toners.
The toner images of each color formed on 101M, 101Y and 101K are superimposed on the transfer paper. The transfer paper 107 is sent out of the tray by a paper feed roller 108, temporarily stopped by a pair of registration rollers 109, and sent to the transfer conveyance belt 110 at the same time as the image formation on the photoconductor. Transfer paper 107 held on transfer / conveyance belt 110
Is conveyed to each of the photoconductors 101C, 101M, 101
The transfer of the toner image of each color is performed at the contact position (transfer portion) with Y and 101K. The toner image on the photoconductor is transferred to the transfer brush 1
The transfer bias applied to 11C, 111M, 111Y, 111K and the photoconductors 101C, 101M, 101Y, 1
Transfer paper 1 due to the electric field formed from the potential difference
07. After passing through the four transfer sections,
The transfer paper 107 on which the color toner images are superimposed is transferred to the fixing device 11.
2, the toner is fixed, and the paper is discharged to a paper discharge unit (not shown). Further, each photoconductor 1 is not transferred at the transfer section.
Residual toner remaining on 01C, 101M, 101Y and 101K is removed by cleaning devices 105C, 105M and 10K.
Collected at 5Y, 105K. In the example shown in FIG. 1, the image forming element is moved from the upstream side to the downstream side in the transfer paper transport direction.
The colors are arranged in the order of (cyan), M (magenta), Y (yellow), and K (black), but are not limited to this order, and the color order can be set arbitrarily. Also,
When a black-only document is created, providing a mechanism for stopping the image forming elements (106C, 106M, 106Y) other than black can be particularly effectively used in the present invention.
Further, although the charging member is in contact with the photoreceptor in FIG. 10, by providing an appropriate gap (about 10 to 200 μm) between the two, the amount of wear of both can be reduced and the charging member Less toner filming and good use.

The image forming means as described above may be fixedly incorporated in a copying machine, a facsimile, or a printer, but each electrophotographic element is incorporated in the apparatus in the form of a process cartridge. Is also good. The process cartridge is one device (part) that includes a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a charge removing unit, and the like.

[0111]

The present invention will be described below with reference to examples.
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 applied and dried on an aluminum cylinder to obtain a 3.5 μm undercoat layer. An electrophotographic photoreceptor comprising a 0.2 μm charge generation layer, a 20 μm charge transport layer, and a 5 μm protective layer was formed. The undercoat layer, the charge generation layer and the charge transport layer were applied by a dip coating method, and the protective layer was applied by a spray method. ◎ Coating solution for undercoat layer 400 parts of titanium dioxide powder 65 parts of melamine resin 120 parts of alkyd resin 400 parts of 2-butanone ◎ Coating solution of 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 A type polycarbonate 10 parts Charge transport material of the following structural formula 8 parts

Embedded image 200 parts of tetrahydrofuran ◎ Coating liquid for protective layer 1 10 parts of C-type polycarbonate 7 parts of a charge transport material having the following structural formula

Embedded image Alumina fine particles (Specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.2 μm) 5 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating liquid for protective layer 2 C-type polycarbonate 10 parts Charge transport material having the following structural formula 7 copies

Embedded image 2.5 parts alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.2 μm) 2.5 parts alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) 2.5 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution for protective layer 3 C-type polycarbonate 10 parts Charge transport material of the following structural formula 7 parts

Embedded image Alumina fine particles (Specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) 5 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts

The above surface layer coating liquid was the surface layer coating liquid 1,
Using three spray heads in the order of 2, 3, coating was continuously performed by a spray method. In this case, continuous means that the next coating liquid is laminated by a spraying method after the lower layer is coated and before touch drying. The protective layer coating liquids 1 and 2 were 2 μm.
m, and the protective layer coating liquid 3 was applied in an amount of 1 μm to form a protective layer having a total thickness of 5 μm.

Example 2 A photoconductor was prepared by the same way as that of Example 1 except that the coating liquids 1, 2 and 3 for protective layer in Example 1 were changed to the following compositions. ◎ Protective layer coating liquid 1 7 parts of polymer charge transport material of the following structural formula

Embedded image Alumina fine particles (Specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.2 μm) 2 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution 2 for protective layer 7 parts of polymer charge transporting material having the following structural formula

Embedded image 1 part of fine alumina particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.2 μm) 1 part of fine alumina particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution 3 for protective layer 7 parts of polymer charge transport material having the following structural formula

Embedded image Alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) 2 parts 400 parts tetrahydrofuran 200 parts 200 parts cyclohexanone

Comparative Example 1 A photoconductor was prepared in the same manner as in Example 1, except that only the protective layer coating liquid 1 was used as the protective layer to form a protective layer having a thickness of 5 μm.

Comparative Example 2 The protective layer in Example 1 was prepared using only the protective layer coating liquid 2.
A photoconductor was prepared in the same manner as in Example 1, except that a protective layer of 5 μm was formed.

Comparative Example 3 The protective layer in Example 1 was prepared using only the protective layer coating liquid 3.
A photoconductor was prepared in the same manner as in Example 1, except that a protective layer of 5 μm was formed.

Comparative Example 4 The protective layer in Example 2 was prepared using only the protective layer coating liquid 1.
A photoconductor was prepared in the same manner as in Example 2 except that a protective layer having a thickness of 5 μm was formed.

Comparative Example 5 The protective layer in Example 2 was prepared using only the protective layer coating liquid 2.
A photoconductor was prepared in the same manner as in Example 2 except that a protective layer having a thickness of 5 μm was formed.

Comparative Example 6 The protective layer in Example 2 was prepared using only the protective layer coating liquid 3.
A photoconductor was prepared in the same manner as in Example 2 except that a protective layer having a thickness of 5 μm was formed.

Test Example 1 Examples 1 and 2 and Comparative Examples 1 to 6 produced as described above.
The photoreceptor was mounted on an electrophotographic process shown in FIG. 5 (however, there was no exposure before cleaning, the charging member was a scorotron charger), and the image exposure light source was a 655 nm semiconductor laser (image writing by a polygon mirror). Printing was continuously performed on 20,000 sheets, and the images at that time were evaluated at the initial stage and after 20,000 sheets. Further, the abrasion amount of the photoreceptor surface after 20,000 sheets was also measured. The above results are also shown in Table 1.

[Table 1]

Example 3 The charging member of the electrophotographic process shown in FIG. 3 used in Example 1 was changed from a scorotron charger to a charging roller, and the charging member was arranged so as to contact the photosensitive member. The photoconductor produced in Example 1 is mounted on this apparatus,
The same evaluation as in Example 1 was performed under the following charging conditions. Charging condition: DC bias: -850V

Both the initial image and the 20,000th image were good, but the image after 20,000th sheet showed a very slight abnormal image (ground stain) due to the charging roller stain (toner filming). Was done. However, the ozone odor during continuous printing was much less than in the case of Example 1.

Example 4 The charging roller used in Example 3 had a thickness of 50 μm on both ends.
m, insulating tape with a width of 5 mm, and a space gap (50 μm) between the surface of the charging roller and the surface of the photoreceptor
It was arranged so that it might have. The other conditions were evaluated exactly as in Example 3. As a result, the charging roller stains observed in Example 3 were not recognized at all, and both the initial and 20,000th images were good. However, 2
When a halftone image was output after 10,000 copies, image unevenness due to uneven charging was observed, albeit very slightly.

Example 5 Evaluation was performed in the same manner as in Example 4 except that the charging conditions were changed as follows. Charging conditions: DC bias: -850 V AC bias: 1.8 kV (peak to peak)
k), frequency 1.7 kHz

The images at the initial stage and after 20,000 sheets were good.
The charging roller stains observed in Example 3 and the halftone image unevenness observed in Example 4 were not observed at all.

Example 6 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 a nickel belt. 3 μm charge generation layer, 2
An electrophotographic photosensitive member comprising a 2 μm charge transport layer and a 3 μm protective layer was formed. The undercoat layer, the charge generation layer and the charge transport layer were applied by a dip coating method, and the protective layer was applied by a spray method. ◎ Undercoat layer coating liquid Titanium dioxide powder 100 parts Alcohol-soluble nylon 100 parts Methanol 500 parts Butanol 300 parts ◎ Charge generating layer coating liquid Bisazo pigment having the following structure 10 parts

Embedded image Polyvinyl butyral 2 parts 2-butanone 200 parts Cyclohexanone 400 parts ◎ Charge transport layer coating liquid Z-type polycarbonate 10 parts Charge transport material of the following structural formula 7 parts

Embedded image 200 parts of tetrahydrofuran ◎ Coating liquid for protective layer 1 10 parts of Z-type polycarbonate 6 parts of charge transport material of the following structural formula

Embedded image Titanium oxide fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.1 μm) 5 parts Toluene 600 parts ◎ Protective layer coating liquid 2 Z-type polycarbonate 10 parts Charge transport material of the following structural formula 6 parts

Embedded image Titanium oxide fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.1 μm) 3 parts Titanium oxide fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) 2 parts Toluene 600 parts ◎ Protective layer coating liquid 3 Z-type polycarbonate 10 parts Charge transport material of the following structural formula 6 parts

Embedded image Titanium oxide fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) 5 parts Toluene 600 parts

The above-mentioned protective layer coating liquid is the protective layer coating liquid 1,
Using three spray heads in the order of 2, 3, coating was continuously performed by a spray method. In this case, continuous means that the next coating liquid is laminated by a spraying method after the lower layer is coated and before touch drying. The protective layer coating liquids 1, 2, and 3 were applied in an amount of 1 μm each to form a protective layer having a total thickness of 3 μm.

Example 7 A photoconductor was prepared by the same way as that of Example 6 except that the coating liquids for protective layer 1, 2 and 3 in Example 6 were changed to the following compositions. ◎ Protective layer coating liquid 1 7 parts of polymer charge transport material of the following structural formula

Embedded image Alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.3 μm) 3 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution for protective layer 2 7 parts of polymer charge transport material having the following structural formula

Embedded image Silica fine particles (specific resistance: 4 × 10 ¹³ Ω · cm, average primary particle size: 0.5 μm) 2 parts Alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.3 μm) 1 part Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution for protective layer 3 Polymer charge transporting material of the following structural formula 7 parts

Embedded image Silica fine particles (specific resistance: 4 × 10 ¹³ Ω · cm, average primary particle size: 0.5 μm) 3 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts

Comparative Example 7 The protective layer in Example 6 was prepared using only the protective layer coating liquid 1.
A photoconductor was prepared in the same manner as in Example 6, except that a protective layer having a thickness of 3 μm was formed.

Comparative Example 8 The protective layer in Example 6 was prepared using only the protective layer coating liquid 2.
A photoconductor was prepared in the same manner as in Example 6, except that a protective layer having a thickness of 3 μm was formed.

Comparative Example 9 The protective layer in Example 6 was prepared using only the protective layer coating liquid 3.
A photoconductor was prepared in the same manner as in Example 6, except that a protective layer having a thickness of 3 μm was formed.

Comparative Example 10 The charge transporting layer of Example 6 was used without the protective layer
A photoconductor was prepared in the same manner as in Example 6, except that the thickness was changed to μm.

Comparative Example 11 The protective layer in Example 7 was prepared using only the protective layer coating liquid 1.
A photoconductor was prepared in the same manner as in Example 7, except that a protective layer having a thickness of 3 μm was formed.

Comparative Example 12 The protective layer in Example 7 was prepared using only the protective layer coating liquid 2.
A photoconductor was prepared in the same manner as in Example 7, except that a protective layer having a thickness of 3 μm was formed.

Comparative Example 13 The protective layer in Example 7 was prepared using only the protective layer coating liquid 3.
A photoconductor was prepared in the same manner as in Example 7, except that a protective layer having a thickness of 3 μm was formed.

Test Example 2 Examples 6 and 7 and Comparative Examples 7-1 produced as described above
The photoconductor of No. 3 was subjected to the electrophotographic process shown in FIG.
(No pre-cleaning exposure), the image exposure light source was a 655 nm LED, and 30,000 sheets were printed continuously, and the images at that time were evaluated at the initial stage and after 30,000 sheets. Furthermore,
The amount of abrasion on the surface of the photoreceptor after 30,000 sheets was also measured. The above results are also shown in Table 2.

[0138]

[Table 2]

Example 8 The filler used in Example 6 was subjected to a surface treatment with a titanate coupling agent so that the treatment amount was 20%. Using this filler, protective layer coating liquids 1, 2, and 3 in Example 6 were produced. These were evaluated for the average particle size in the coating solution (measured by CAPA500, Horiba, Ltd.) and the sedimentation of the coating solution (the sedimentation degree of the coating solution particles left standing in a test tube was visually checked). Table 3 shows the results. The values shown in Table 3 are the measurement results of the respective protective layer coating liquids 3.

Example 9 The filler used in Example 6 was subjected to a surface treatment with Al ₂ O ₃ so that the processing amount became 20%. Using this filler, the protective layer coating liquids 1, 2, and 3 in Example 6 were used.
Was prepared. These were evaluated for the average particle size in the coating liquid (measured by CAPA700, Horiba, Ltd.) and the sedimentation of the coating liquid (the degree of sedimentation of the coating liquid particles left standing in a test tube was visually confirmed). Table 3 shows the results. Table 3
Are the measurement results of the respective protective layer coating liquids 3.

[0141]

[Table 3]

Example 10 A photoconductor was prepared in the same manner as in Example 6, except that the dispersion prepared in Example 8 was used. In addition, as a sample for transmittance measurement,
Only the protective layer was formed on the polyester film. Table 4 shows the appearance results, the surface roughness Rz, and the transmittance at 655 nm of the photoreceptor.

Example 11 A photoconductor was prepared in the same manner as in Example 6, except that the dispersion prepared in Example 9 was used. In addition, only a protective layer was formed on a polyester film as a transmittance measurement sample.
Table 4 shows the results of the appearance of the photoreceptor, the surface roughness Rz and the transmittance at 655 nm.

[0144]

[Table 4]

Example 12 The photosensitive member produced in Example 10 was mounted on the same apparatus as used in the evaluation in Example 6 described above, and image evaluation was performed. As a result, the photoconductor using the dispersion of Example 6 was more effective than that of Example 8
The resolution of the photoreceptor using the dispersion was superior.

Example 13 The photosensitive member produced in Example 11 was mounted on the same apparatus as used in the evaluation in Example 6 described above, and image evaluation was performed. As a result, the photoconductor using the dispersion of Example 6 was more excellent than that of Example 9
The resolution of the photoreceptor using the dispersion was superior.

Example 14 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, a 21 μm charge transport layer and a 4 μm protective layer was formed. ◎ Coating liquid for undercoat layer 400 parts of titanium dioxide powder 65 parts of melamine resin 120 parts of alkyd resin 400 parts of 2-butanone ◎ Coating liquid for charge generating layer 8 parts of titanyl phthalocyanine having an XD spectrum shown in FIG. JP-A-2005-122, pp. 5-7. Polyvinyl butyral 5 parts 2-butanone 400 parts ◎ Charge transport layer coating liquid Z-type polycarbonate 10 parts Charge transport material of the following structural formula 7 parts

Embedded image 80 parts of methylene chloride ◎ Coating solution for protective layer 1 10 parts of polyarylate 8 parts of charge transport material of the following structural formula

Embedded image Alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.2 μm) 6 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating liquid 2 for protective layer 10 parts Polyarylate 10 parts Charge transport material of the following structural formula 8 Department

Embedded image Alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.2 μm) 4 parts Alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) 2 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution for protective layer 3 Polyarylate 10 parts Charge transport material of the following structural formula 8 parts

Embedded image Alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) 6 parts 400 parts tetrahydrofuran 200 parts cyclohexanone 200 parts

The above-mentioned protective layer coating liquid is the protective layer coating liquid 1,
Using three spray heads in the order of 2, 3, coating was continuously performed by a spray method. In this case, continuous means that the next coating liquid is laminated by a spraying method after the lower layer is coated and before touch drying. The protective layer coating liquids 1 and 2 contained 1.
The protective layer coating liquid 3 was applied in an amount equivalent to 1 μm to form a protective layer having a total thickness of 4 μm.

Comparative Example 14 A photoconductor was prepared in the same manner as in Example 14 except that the protective layer in Example 14 was formed using only the protective layer coating liquid 1 and a 4 μm protective layer was formed.

Comparative Example 15 A photoreceptor was produced in the same manner as in Example 14, except that the protective layer in Example 14 was formed using only the protective layer coating solution 1 and a 4 μm protective layer was formed.

Comparative Example 16 A photoconductor was prepared in the same manner as in Example 14, except that only the protective layer coating liquid 3 was used as the protective layer and a 4 μm protective layer was formed.

Comparative Example 17 The charge transport layer was replaced with the charge transport layer of Example 14 without laminating the protective layer.
A photoconductor was prepared by the same way as that of Example 11 except that the thickness was 5 μm.

Test Example 3 Example 14 and Comparative Examples 14 to 1 manufactured as described above
The photoreceptor No. 7 was mounted on the electrophotographic process cartridge shown in FIG. 7, and the image exposure light source was a 780 nm semiconductor laser (image writing using a polygon mirror).
20,000 sheets are printed continuously, and the image at that time is
Evaluation was performed after 10,000 sheets. Further, the abrasion amount of the photoreceptor surface after 20,000 sheets was also measured. The above results are also shown in Table 5.

[0154]

[Table 5]

Example 15 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. An electrophotographic photoreceptor comprising a 0.2 μm charge generation layer, a 20 μm charge transport layer, and a 5 μm protective layer was formed. The undercoat layer, the charge generation layer and the charge transport layer were applied by a dip coating method, and the protective layer was applied by a spray method. ◎ Coating solution for undercoat layer 400 parts of titanium dioxide powder 65 parts of melamine resin 120 parts of alkyd resin 400 parts of 2-butanone ◎ Coating solution of 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 A type polycarbonate 10 parts Charge transport material of the following structural formula 8 parts

Embedded image 200 parts of tetrahydrofuran ◎ Coating liquid for protective layer 1 10 parts of C-type polycarbonate 7 parts of a charge transport material having the following structural formula

Embedded image Alumina fine particles (Specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.2 μm) 5 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating liquid for protective layer 2 C-type polycarbonate 10 parts Charge transport material having the following structural formula 7 copies

Embedded image 2.5 parts alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.2 μm) 2.5 parts alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) 2.5 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution for protective layer 3 C-type polycarbonate 10 parts Charge transport material of the following structural formula 7 parts

Embedded image Alumina fine particles (Specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) 5 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts

The above-mentioned protective layer coating liquid was the protective layer coating liquid 1,
Using three spray heads in the order of 2, 3, coating was performed sequentially by the spray method. The term “sequential coating” means that after the lower layer is coated and the touch drying is completed, the next coating liquid is laminated by a spray method. The protective layer coating liquids 1 and 2 were 2 μm.
m, and the protective layer coating liquid 3 was applied in an amount of 1 μm to form a protective layer having a total thickness of 5 μm.

Example 16 A photoconductor was prepared by the same way as that of Example 15 except that the coating liquids for protective layer 1, 2 and 3 in Example 15 were changed to the following compositions. ◎ Protective layer coating liquid 1 7 parts of polymer charge transport material of the following structural formula

Embedded image Alumina fine particles (Specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.2 μm) 2 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution 2 for protective layer 7 parts of polymer charge transporting material having the following structural formula

Embedded image 1 part of fine alumina particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.2 μm) 1 part of fine alumina particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution 3 for protective layer 7 parts of polymer charge transport material having the following structural formula

Embedded image Alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) 2 parts 400 parts tetrahydrofuran 200 parts 200 parts cyclohexanone

Comparative Example 18 A photoconductor was prepared in the same manner as in Example 15 except that the protective layer in Example 15 was formed using only the protective layer coating solution 1 and a protective layer of 5 μm was formed.

Comparative Example 19 A photoconductor was prepared in the same manner as in Example 15 except that the protective layer in Example 15 was formed using a protective layer coating liquid 2 alone and a protective layer of 5 μm was formed.

Comparative Example 20 A photoconductor was prepared in the same manner as in Example 15 except that the protective layer in Example 15 was formed using only the protective layer coating liquid 3 and a protective layer of 5 μm was formed.

Comparative Example 21 A photoconductor was prepared in the same manner as in Example 16 except that only the protective layer coating liquid 1 was used as the protective layer and a 5 μm protective layer was formed.

Comparative Example 22 A photoconductor was prepared in the same manner as in Example 16 except that the protective layer in Example 16 was formed using only the protective layer coating liquid 2 and a protective layer of 5 μm was formed.

Comparative Example 23 A photoconductor was prepared in the same manner as that of Example 16 except that the protective layer in Example 16 was formed using only the protective layer coating liquid 3 and a protective layer of 5 μm was formed.

Test Example 4 Examples 15 and 16 and Comparative Example 1 produced as described above
The photosensitive members Nos. 8 to 23 were mounted on the electrophotographic process shown in FIG. 5 (however, no pre-cleaning exposure was performed, and the charging member was a scorotron charger).
As a 5 nm semiconductor laser (image writing using a polygon mirror), 20,000 sheets were continuously printed, and the images at that time were evaluated at the initial stage and after 20,000 pages. Further, the abrasion amount of the photoreceptor surface after 20,000 sheets was also measured. The above results are also shown in Table 6.

[Table 6]

Example 17 The charging member of the electrophotographic process shown in FIG. 5 used in Example 15 was changed from a scorotron charger to a charging roller, and the charging roller was arranged so as to contact the photosensitive member. The photoconductor produced in Example 1 was mounted on this device, and the same evaluation as in Example 15 was performed under the following charging conditions. Charging condition: DC bias: -900V

Both the initial image and the 20,000th image were good, but the image after 20,000th sheet showed a very slight abnormal image (ground stain) based on the charge roller stain (toner filming). Was done. However, the ozone odor during continuous printing was significantly less than that in Example 15.

Example 18 A thickness of 50 was applied to both ends of the charging roller used in Example 17.
A 5 μm-wide insulating tape is attached, and a spatial gap (50 μm) is formed between the surface of the charging roller and the surface of the photoreceptor.
m). Other conditions were the same as in Example 1.
The evaluation was performed in exactly the same manner as in Example 7. As a result, the charging roller stains observed in Example 3 were not recognized at all, and both the initial and 20,000th images were good. However, when the halftone image was output after 20,000 sheets, although very slight, image unevenness due to charging unevenness was observed.

Example 19 The same evaluation as in Example 18 was performed, except that the charging conditions were changed as follows. Charging conditions: DC bias: -900 V AC bias: 1.8 kV (peak to peak)
k), frequency 2 kHz

The images at the initial stage and after 20,000 sheets were good.
Charging roller contamination found in Example 17, Example 18
Was not observed at all.

Example 20 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 a nickel belt. 3 μm charge generation layer, 2
An electrophotographic photoreceptor comprising a 2 μm charge transport layer and a 3 μm protective layer was formed. The undercoat layer, the charge generation layer and the charge transport layer were applied by a dip coating method, and the protective layer was applied by a spray method. ◎ Undercoat layer coating liquid Titanium dioxide powder 100 parts Alcohol-soluble nylon 100 parts Methanol 500 parts Butanol 300 parts ◎ Charge generating layer coating liquid Bisazo pigment having the following structure 10 parts

Embedded image Polyvinyl butyral 2 parts 2-butanone 200 parts Cyclohexanone 400 parts ◎ Charge transport layer coating liquid Z-type polycarbonate 10 parts Charge transport material of the following structural formula 7 parts

Embedded image 200 parts of tetrahydrofuran ◎ Coating liquid for protective layer 1 10 parts of Z-type polycarbonate 6 parts of charge transport material of the following structural formula

Embedded image Titanium oxide fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.1 μm) 5 parts Toluene 600 parts ◎ Protective layer coating liquid 2 Z-type polycarbonate 10 parts Charge transport material of the following structural formula 6 parts

Embedded image Titanium oxide fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.1 μm) 3 parts Titanium oxide fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) 2 parts Toluene 600 parts ◎ Protective layer coating liquid 3 Z-type polycarbonate 10 parts Charge transport material of the following structural formula 6 parts

Embedded image Titanium oxide fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) 5 parts Toluene 600 parts

The above-mentioned protective layer coating liquid is the protective layer coating liquid 1,
Using three spray heads in the order of 2, 3, coating was performed sequentially by the spray method. The term “sequential coating” means that after the lower layer is coated and the touch drying is completed, the next coating liquid is laminated by a spray method. The protective layer coating liquids 1, 2, and 3 were applied in an amount of 1 μm each to form a protective layer having a total thickness of 3 μm.

Example 21 A photoconductor was prepared by the same way as that of Example 20 except that the coating solutions 1, 2 and 3 of protective layer in Example 20 were changed to the following compositions. ◎ Protective layer coating liquid 1 7 parts of polymer charge transport material of the following structural formula

Embedded image Alumina fine particles (resistivity: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.3 μm) 3 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution for protective layer 2 7 parts of polymer charge transporting material having the following structural formula

Embedded image Silica fine particles (specific resistance: 4 × 10 ¹³ Ω · cm, average primary particle size: 0.5 μm) 1 part Alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.3 μm) 2 parts Tetrahydrofuran 400 Part Cyclohexanone 200 parts ◎ Coating solution for protective layer 3 Polymer charge transport material of the following structural formula 7 parts

Embedded image Silica fine particles (specific resistance: 4 × 10 ¹³ Ω · cm, average primary particle size: 0.5 μm) 3 parts 400 parts tetrahydrofuran 200 parts 200 parts cyclohexanone

Comparative Example 24 A photoconductor was prepared in the same manner as in Example 20, except that only the protective layer coating liquid 1 was used as the protective layer and a protective layer of 3 μm was formed.

Comparative Example 25 A photoconductor was prepared in the same manner as in Example 20 except that the protective layer in Example 20 was formed using a protective layer coating liquid 2 alone and a protective layer of 3 μm was formed.

Comparative Example 26 A photoconductor was prepared in the same manner as in Example 20, except that the protective layer in Example 20 was formed using a protective layer coating liquid 3 alone and a protective layer of 3 μm was formed.

Comparative Example 27 The charge-transporting layer of Example 20 was used without the protective layer
A photoconductor was prepared by the same way as that of Example 20 except that the thickness was 5 μm.

Comparative Example 28 A photoconductor was prepared in the same manner as in Example 21 except that only the protective layer coating liquid 1 was used as the protective layer and a protective layer of 3 μm was formed.

Comparative Example 29 A photoconductor was prepared in the same manner as that of Example 21 except that the protective layer in Example 21 was formed using a protective layer coating liquid 2 alone and a protective layer of 3 μm was formed.

Comparative Example 30 A photoconductor was prepared in the same manner as in Example 21 except that the protective layer in Example 21 was formed using a protective layer coating liquid 3 alone, and a protective layer of 3 μm was formed.

Test Example 5 Examples 20 and 21 and Comparative Example 2 produced as described above
The photosensitive members 4 to 30 were mounted in the electrophotographic process shown in FIG. 6 (however, there was no pre-cleaning exposure), and an image exposure light source of 655 nm LED was used to continuously print 30,000 sheets. The images were evaluated initially and after 30,000 copies.
Further, the amount of abrasion on the photoreceptor surface on 30,000 sheets was also measured. The above results are also shown in Table 7.

[Table 7]

Example 22 The filler used in Example 20 was subjected to a surface treatment with a titanate coupling agent so that the treatment amount was 20%. Using this filler, protective layer coating liquids 1, 2, and 3 in Example 20 were prepared. These were evaluated for the average particle size in the coating liquid (measured by CAPA700, Horiba, Ltd.) and the sedimentation of the coating liquid (the degree of sedimentation of the coating liquid particles left standing in a test tube was visually confirmed). Table 8 shows the results. The values shown in Table 8 are the measurement results of the respective protective layer coating liquids 3.

Example 23 The filler used in Example 20 was subjected to a surface treatment with Al ₂ O ₃ so that the processing amount became 20%. Using this filler, the protective layer coating liquids 1, 2, and 3 in Example 6 were used.
Was prepared. These were evaluated for the average particle size in the coating liquid (measured by CAPA700, Horiba, Ltd.) and the sedimentation of the coating liquid (the degree of sedimentation of the coating liquid particles left standing in a test tube was visually confirmed). Table 8 shows the results. Table 8
Are the measurement results of the respective protective layer coating liquids 3.

[0183]

[Table 8]

Example 24 A photoconductor was prepared in the same manner as in Example 20, except that the dispersion prepared in Example 22 was used. In addition, only a protective layer was formed on a polyester film as a transmittance measurement sample.
Table 9 shows the appearance results of the photoreceptor, the surface roughness Rz, and the transmittance at 655 nm.

Example 25 A photoreceptor was produced in the same manner as in Example 20, except that the dispersion prepared in Example 23 was used. In addition, only a protective layer was formed on a polyester film as a transmittance measurement sample.
Table 9 shows the appearance results of the photoreceptor, the surface roughness Rz, and the transmittance at 655 nm.

[0186]

[Table 9]

Example 26 The photoreceptor prepared in Example 24 was mounted on the same apparatus as used in the evaluation of Example 20 above, and image evaluation was performed. As a result, the resolution of the photoconductor using the dispersion of Example 22 was superior to that of the photoconductor using the dispersion of Example 20.

Example 27 The photosensitive member produced in Example 25 was mounted on the same apparatus as used in the evaluation in Example 6 described above, and image evaluation was performed. As a result, the resolution of the photoconductor using the dispersion of Example 23 was superior to that of the photoconductor using the dispersion of Example 20.

Example 28 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, a 21 μm charge transport layer and a 4 μm protective layer was formed. ◎ Coating solution for undercoat layer 400 parts of titanium dioxide powder 65 parts of melamine resin 120 parts of alkyd resin 400 parts of 2-butanone ◎ Coating solution for charge generating layer 8 parts of titanyl phthalocyanine having the XD spectrum of FIG. (Titanyl phthalocyanine described in the official gazette) 5 parts of polyvinyl butyral 400 parts of 2-butanone ◎ Coating liquid for charge transport layer 10 parts of Z-type polycarbonate 7 parts of charge transport material of the following structural formula

Embedded image 80 parts of methylene chloride ◎ Coating solution for protective layer 1 10 parts of polyarylate 8 parts of charge transport material of the following structural formula

Embedded image Alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.2 μm) 6 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating liquid 2 for protective layer 10 parts Polyarylate 10 parts Charge transport material of the following structural formula 8 Department

Embedded image Alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.2 μm) 4 parts Alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) 2 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution for protective layer 3 Polyarylate 10 parts Charge transport material of the following structural formula 8 parts

Embedded image Alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm) 6 parts 400 parts tetrahydrofuran 200 parts cyclohexanone 200 parts

The above-mentioned protective layer coating liquid is the protective layer coating liquid 1,
Using three spray heads in the order of 2, 3, coating was performed sequentially by the spray method. The term “sequential coating” means that after the lower layer is coated and the touch drying is completed, the next coating liquid is laminated by a spray method. The protective layer coating liquids 1 and 2 contained 1.
The protective layer coating liquid 3 was applied in an amount equivalent to 1 μm to form a protective layer having a total thickness of 4 μm.

Comparative Example 31 A photoconductor was prepared by the same way as that of Example 28 except that the protective layer in Example 28 was formed using only the protective layer coating liquid 1, and the protective layer having a thickness of 4 μm was formed.

Comparative Example 32 A photoconductor was prepared in the same manner as that of Example 28 except that the protective layer in Example 28 was formed using only the protective layer coating liquid 1 and a protective layer of 4 μm was formed.

Comparative Example 33 A photoconductor was prepared by the same way as that of Example 28 except that the protective layer of Example 28 was formed using only the protective layer coating liquid 3, and the protective layer was 4 μm in thickness.

Comparative Example 34 The charge transport layer was replaced with the charge transport layer in Example 28 without laminating the protective layer.
A photoconductor was prepared by the same way as that of Example 28 except that the thickness was 5 μm.

Test Example 6 Example 28 and Comparative Examples 31 to 3 manufactured as described above
The photoreceptor No. 4 was mounted on the electrophotographic process cartridge shown in FIG. 7, and the image exposure light source was a 780 nm semiconductor laser (image writing using a polygon mirror).
20,000 sheets are printed continuously, and the image at that time is
Evaluation was performed after 10,000 sheets. Further, the abrasion amount of the photoreceptor surface after 20,000 sheets was also measured. The above results are also shown in Table 10.

[Table 10]

Example 29 A photoconductor was prepared by the same way as that of Example 7 except that the coating liquids for protective layer 1, 2 and 3 in Example 7 were changed to the following compositions. ◎ Protective layer coating liquid 1 7 parts of polymer charge transport material of the following structural formula

Embedded image Silica fine particles (resistivity: 4 × 10 ¹³ Ω · cm, average primary particle size: 0.3 μm) 3 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution for protective layer 2 7 parts of polymer charge transporting material having the following structural formula

Embedded image Silica fine particles (specific resistance: 4 × 10 ¹³ Ω · cm, average primary particle size: 0.5 μm) 2 parts Silica fine particles (specific resistance: 4 × 10 ¹³ Ω · cm, average primary particle size: 0.3 μm) 1 part Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution for protective layer 3 7 parts of polymer charge transport material having the following structural formula

Embedded image Silica fine particles (specific resistance: 4 × 10 ¹³ Ω · cm, average primary particle size: 0.5 μm) 3 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts

Test Example 7 The photoconductors prepared in Examples 7 and 29 were mounted in the electrophotographic process shown in FIG. 6 (however, there was no pre-cleaning exposure), and the image exposure light source was a 655 nm LED. Then, 30,000 sheets were printed, and the photoconductor surface potential (exposed area and unexposed area) at that time was evaluated. Table 1 shows the results
It is shown in FIG.

[Table 11]

Example 30 A photoconductor was prepared by the same way as that of Example 21 except that the coating liquids for protective layer 1, 2 and 3 in Example 21 were changed to the following compositions. ◎ Protective layer coating liquid 1 7 parts of polymer charge transport material of the following structural formula

Embedded image Silica fine particles (Specific resistance: 4 × 10 ¹³ Ω · cm, average primary particle size: 0.3 μm) 3 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution for protective layer 2 7 parts of polymer charge transport material having the following structural formula

Embedded image Silica fine particles (specific resistance: 4 × 10 ¹³ Ω · cm, average primary particle size: 0.5 μm) 1 part Silica fine particles (specific resistance: 4 × 10 ¹³ Ω · cm, average primary particle size: 0.3 μm) 2 parts Tetrahydrofuran 400 parts Cyclohexanone 200 parts ◎ Coating solution for protective layer 3 7 parts of polymer charge transport material having the following structural formula

Embedded image Silica fine particles (specific resistance: 4 × 10 ¹³ Ω · cm, average primary particle size: 0.5 μm) 3 parts 400 parts tetrahydrofuran 200 parts 200 parts cyclohexanone

Test Example 8 The photoconductors prepared in Examples 21 and 30 were mounted in the electrophotographic process shown in FIG. 6 (however, there was no pre-cleaning exposure), and the image exposure light source was a 655 nm LED and was continuously used. Then, 30,000 sheets were printed, and the photoconductor surface potential (exposed area and unexposed area) at that time was evaluated. Table 1 shows the results
It is shown in FIG.

[Table 12]

Example 31 In Example 28, the conductive support (JIS 1050) was used.
Was subjected to the following anodic oxide film treatment, and then without providing an undercoat layer, a charge generation layer, a charge transport layer,
A protective layer was provided to produce a photoreceptor. ◎ Anodic oxide coating treatment The surface of the support is mirror-polished, degreased and washed with water, then immersed in an electrolytic bath of 20 ° C. and 15 vol% sulfuric acid, and anodized at an electrolytic voltage of 15 V for 30 minutes. A film treatment was performed. After washing with water, sealing treatment was performed with a 7% nickel acetate aqueous solution (50 ° C.). Thereafter, the substrate was washed with pure water to obtain a support on which an anodized film of 6 μm was formed.

Test Example 9 The photoconductors manufactured in Examples 28 and 31
It is mounted on the cartridge for electrophotographic process shown in the figure, and the image exposure light source is a 780 nm semiconductor laser (polygon
(Mirror image writing), 20,000 sheets were continuously printed, and the images at that time were evaluated at the initial stage and after 20,000 sheets. As a result, when the images after 20,000 sheets are compared with each other, there is no problem in practical use. However, dirt (black spots) on the background portion of Example 28 is smaller than that of Example 31. It was slightly more.

Example 32 The photoreceptor prepared in Example 1 was mounted on the electrophotographic apparatus shown in FIG. 10, and all four image forming elements were subjected to image evaluation of 20,000 full-color images under the following process conditions. Was. Table 13 shows the results. Charging conditions DC bias: -800 V AC bias: 2.0 kV (peak to peak)
k), frequency 2 kHz-Exposure condition 655 nm semiconductor laser (image writing by polygon mirror)

Comparative Example 35 An image evaluation test was carried out in the same manner as in Example 32 except that the photoreceptor prepared in Comparative Example 1 was used instead of the photoreceptor used in Example 32. Table 13 shows the results.

Comparative Example 36 An image evaluation test was performed in the same manner as in Example 32 except that the photoreceptor prepared in Comparative Example 3 was used instead of the photoreceptor used in Example 32. Table 13 shows the results.

[Table 13]

[0205]

According to the present invention, there is provided a photosensitive member capable of forming a high-quality image which is highly durable and stable for repeated use. Further, an electrophotographic method, an electrophotographic apparatus, and an electrophotographic process cartridge capable of forming a stable high-quality image at high speed even in repeated use are provided.

[Brief description of the drawings]

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

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

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

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

FIG. 5 is a schematic diagram for explaining the electrophotographic apparatus of the present invention.

FIG. 6 is a schematic diagram for explaining the electrophotographic process of the present invention.

FIG. 7 is a schematic diagram for explaining a process cartridge for an apparatus of the electrophotographic process of the present invention.

FIG. 8 is an XD spectrum of titanyl phthalocyanine used in Example 11.

FIG. 9 is a schematic view showing a non-contact charging mechanism in which a gap holding mechanism is formed on a charging member side.

FIG. 10 is a schematic diagram for explaining a full-color electrophotographic apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductive support 2 Photosensitive layer 3 Protective layer 4 Charge generation layer 5 Charge transport layer 6 Photoconductor 7 Static elimination lamp 8 Charging member 10 Image exposure part 11 Developing unit 12 Pre-transfer charger 13 Resist roller 14 Transfer paper 15 Transfer belt 16 Separation Claw 17 Charger before cleaning 18 Fur brush 19 Cleaning brush 21 Photoreceptor 22 Drive roller 23 Charging roller 24 Image exposure source 25 Transfer charger 26 Light source (exposure before cleaning) 27 Cleaning brush 28 Light source (static light source) 30 Charging member 31 Image exposure unit 32 Cleaning brush 33 Photoconductor 34 Transfer roller 35 Developing roller 36 Photoconductor 37 Charging roller 38 Gap forming member 39 Metal shaft 40 Image forming area 41 Non-image forming area 101C, 101M, 101Y, 101K Photosensitive 102C, 102M, 102Y, 102K Charging member 103C, 103M, 103Y, 103K Laser beam 104C, 104M, 104Y, 104K Developing member 105C, 105M, 105Y, 105K Cleaning member 106C, 106M, 106Y, 106K Image forming element 107 Transfer paper 108 Paper feed roller 109 Registration roller 110 Transfer conveyor belt 111C, 111M, 111Y, 111K Transfer brush 112 Fixing device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 5/06 348 G03G 5/06 348 370 370

Claims (31)

[Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer containing at least an organic charge-generating substance and an organic charge-transporting substance on a conductive support, and a protective layer. An electrophotographic photoreceptor comprising a plurality of types of fillers and having a particle size distribution gradient in which the particle size distribution of the filler in the protective layer continuously increases from the photosensitive layer side to the surface side. 2. An electrophotographic photoreceptor comprising a photosensitive layer containing at least an organic charge-generating substance and an organic charge-transporting substance and a protective layer on a conductive support.
Each protective layer contains two or more fillers having different volume average particle diameters, and the filler particle size distribution in the protective layer increases sequentially from the photosensitive layer side to the surface side. An electrophotographic photosensitive member having a constitution. 3. The filler having a different volume average particle size,
3. The electrophotographic photoconductor according to claim 1, wherein the electrophotographic photoconductor is formed of the same material. 4. The photosensitive layer according to claim 1, wherein the photosensitive layer has a laminated structure of at least a charge generating layer containing an organic charge generating substance and a charge transporting layer containing an organic charge transporting substance. Item 2. The electrophotographic photosensitive member according to Item 1. 5. The method according to claim 1, wherein the organic charge generating substance is an azo pigment or a phthalocyanine pigment.
5. The electrophotographic photoreceptor according to any one of items 4 to 4. 6. The electron according to claim 1, wherein the filler contained in the protective layer is an inorganic pigment or a metal oxide having a specific resistance of 10 ¹⁰ Ω · cm or more. Photoreceptor. 7. The method according to claim 1, wherein the metal oxide is silica, alumina,
7. The electrophotographic photoreceptor according to claim 6, wherein the electrophotographic photoreceptor is selected from the group consisting of titanium oxide and titanium oxide and has a specific resistance of 10 ¹⁰ Ω · cm or more. 8. The pH of the inorganic pigment or metal oxide
The electrophotographic photoreceptor according to claim 6, wherein is 5 or more. 9. The electrophotographic photosensitive member according to claim 6, wherein the dielectric constant of the inorganic pigment or the metal oxide is 5 or more. 10. The inorganic pigment or metal oxide,
The electrophotographic photoreceptor according to any one of claims 6 to 9, wherein the electrophotographic photoreceptor has been subjected to a surface treatment with at least one kind of a surface treatment agent. 11. The surface treating agent for a surface-treated inorganic pigment or metal oxide includes a titanate-based coupling agent, an aluminum-based coupling agent, a higher fatty acid-based, Al ₂ O ₃ , TiO ₂ , and one, or a mixture thereof, or an electrophotographic photosensitive member according to claim 10, wherein the a mixture thereof with a silane coupling agent selected from a group consisting of ZrO _2. 12. The surface-treated inorganic pigment or metal oxide has a surface treatment amount of 3 to 30 wt%.
The electrophotographic photosensitive member according to claim 10 or 11, wherein 13. The method according to claim 1, wherein, among the fillers contained in the protective layer of the photoconductor, the filler having a large volume average particle diameter has an average primary particle diameter of 0.3 μm to 1.0 μm. 13. The electrophotographic photoreceptor according to any one of items 12 to 12. 14. The method according to claim 1, wherein in the region closest to the surface of the protective layer of the photoconductor, the proportion of particles having a large volume average particle diameter among all the fillers contained is 70% or more. 14. The electrophotographic photosensitive member according to any one of the above items 13. 15. The filler used in the protective layer, wherein the specific resistance of the filler having a small volume average particle size is smaller than the specific resistance of the filler having a large volume average particle size. 8. The electrophotographic photosensitive member according to any one of the above. 16. The electrophotographic photoreceptor according to claim 1, wherein the protective layer contains a charge transport material. 17. The charge transport material contained in the protective layer is a polymer charge transport material.
6. The electrophotographic photosensitive member according to 6. 18. The electrophotographic photosensitive member according to claim 17, wherein the polymer charge transporting substance contained in the protective layer is a polycarbonate containing at least a triarylamine structure in a main chain and / or a side chain. body. 19. The electronic device according to claim 1, wherein the protective layer contains a binder resin, and the binder resin contains at least one of a polycarbonate resin and a polyarylate resin. Photoreceptor. 20. The electrophotographic photosensitive member according to claim 1, wherein the surface of the electroconductive support of the electrophotographic photosensitive member has been subjected to an anodic oxide film treatment. 21. A coating method using two or more kinds of coating liquids having different filler particle size distributions by a spray method in order from a liquid having a smaller filler particle size distribution. 2. The method for producing an electrophotographic photoreceptor according to claim 1, wherein the following coating liquid is laminated before drying to form a protective layer having a particle size distribution gradient. 22. A dispersion of two or more fillers having different particle size distributions is spray-coated simultaneously using two or more spray heads, and the ratio of the discharge amount is continuously changed.
The method according to claim 1, wherein a protective layer having a particle size distribution gradient is formed. 23. A coating method in which two or more coating liquids having different filler particle size distributions are applied in order from a liquid having a smaller filler particle size distribution by a spraying method. 3. The method for producing an electrophotographic photosensitive member according to claim 2, wherein the following coating liquid is laminated after drying. 24. An electrophotographic photosensitive member having at least a charge,
21. An electrophotographic method in which image exposure, development, and transfer are repeatedly performed, wherein the electrophotographic photosensitive member is any one of claims 1 to 20.
13. An electrophotographic method, which is the electrophotographic photoreceptor according to item 8. 25. At least charging means, image exposure means,
An electrophotographic apparatus comprising a developing unit, a transfer unit, and an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is provided.
21. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to any one of items 20 to 20. 26. At least charging means, image exposure means,
A so-called digital system in which an electrostatic latent image is written on a photoconductor by using an LD or an LED as an image exposure unit in an electrophotographic apparatus including a developing unit, a transfer unit, and an electrophotographic photoconductor. An electrophotographic apparatus according to claim 1, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 20. 27. At least charging means, image exposure means,
An electrophotographic apparatus comprising a developing unit, a transfer unit, and an electrophotographic photosensitive member, wherein the charging unit is constituted by a charging member in contact with or close to the photosensitive member. An electrophotographic apparatus, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 20. 28. A gap between the charging member and the photoconductor is 200
28. The electrophotographic apparatus according to claim 27, wherein the diameter is not more than μm. 29. The electrophotographic apparatus according to claim 27, wherein in the electrophotographic apparatus, an alternating current component is superimposed on a direct current component on a charging member to charge the photosensitive member. 30. A full-color electrophotographic apparatus in which a plurality of image forming elements each including at least an electrophotographic photosensitive member, a charging unit, an image exposing unit, a developing unit, and a transfer unit are arranged. Item 21. A full-color electrophotographic apparatus, which is the electrophotographic photosensitive member according to any one of Items 1 to 20. 31. 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 20. A process cartridge for an electrophotographic apparatus.