JP4422357B2 - Electrophotographic photosensitive member, process cartridge having the same, and electrophotographic apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic photosensitive member used for a copying machine, a printer, a facsimile, and the like, a process cartridge using the same, and an electrophotographic apparatus, and more specifically, has a recording density of 1200 dots / inch or more to meet the demand for high image quality. The present invention relates to an ultra-high-resolution electrophotographic photosensitive member that can be used, a process cartridge using the same, and an electrophotographic apparatus, and moreover, an electrophotographic photosensitive member that can stably obtain high image quality under high durability and the same. The present invention relates to a process cartridge and an electrophotographic apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, various inorganic and organic photoconductors are widely known as photoconductors of electrophotographic photoreceptors (hereinafter sometimes simply referred to as photoreceptors) used in electrophotography. The “electrophotographic method” here generally means that a photoconductive photosensitive member is first charged in a dark place, for example, by corona discharge, and then subjected to image exposure, whereby the charge of only the exposed portion is selectively dissipated and static. This is called the Carlson process, in which an electrostatic latent image is obtained, and this latent image portion is developed with a toner composed of a colorant such as a dye or pigment and a polymer material, and visualized to form an image. This is an image forming process.
[0003]
Photoconductors using organic photoconductors are more advantageous than those of inorganic photoconductors in terms of freedom of photosensitive wavelength range, film formability, flexibility, film transparency, mass productivity, toxicity, cost, etc. At present, organic photoconductors are used for most photoconductors. Photoreceptors repeatedly used in this electrophotographic system and similar processes have excellent electrostatic characteristics such as sensitivity, receptive potential, potential retention, potential stability, residual potential, and spectral sensitivity characteristics. Required.
[0004]
In recent years, there has been a remarkable development of information processing system machines using electrophotography. In particular, a printer using a digital recording system that converts information into a digital signal and records information by light has a remarkable improvement in print quality and reliability. This digital recording system is applied not only to printers but also to ordinary copying machines, and so-called digital copying machines have been developed. Furthermore, since various digital information processing functions are added to the digital copying machine, it is expected that the demand for the digital copying machine will increase further in the future.
[0005]
The electrophotographic photoreceptors currently used in these systems generally have a so-called functional separation in which a charge generation layer is formed directly on a conductive support or via an intermediate layer, and a charge transport layer is provided thereon. Type laminated photoconductors are the mainstream. Furthermore, a surface protective layer is formed on the outermost surface of the photoreceptor in order to improve mechanical or chemical durability. In this function-separated laminated photoconductor, when a photoconductor whose surface is charged is exposed, light passes through the charge transport layer and is absorbed by the charge generation material in the charge generation layer. The charge generating material absorbs this light and generates charge carriers. The generated charge carriers are injected into the charge transport layer and move along the electric field generated by charging to neutralize the surface charge of the photoreceptor. As a result, an electrostatic latent image is formed on the surface of the photoreceptor. Therefore, the function-separated type multilayer photosensitive member mainly has a charge generation material having absorption from the near infrared part to the visible part, and does not prevent transmission of absorbed light of the charge generation material, that is, from the visible part (yellow light region) to the ultraviolet part. Many combinations with charge transport materials with absorption are used.
[0006]
As a light source adapted to such a digital recording method, for example, a small and inexpensive semiconductor laser (LD) or light emitting diode (LED) with high reliability is often used. The oscillation wavelength region of the LD that is most often used at present is in the near infrared light region near 780 to 800 nm. The emission wavelength of a typical LED is 740 nm.
[0007]
On the other hand, recently, purple to blue short wavelength LDs and LEDs having an oscillation wavelength of 400 to 450 nm have been developed and listed as writing light sources corresponding to this digital recording system. For example, when a short wavelength LD whose oscillation wavelength is about half that of a conventional near infrared region LD is used as a writing light source, the spot diameter of the laser beam on the photosensitive member is expressed by the following equation (3). In theory can be made quite small. Therefore, they are very advantageous for increasing the writing density or resolution of the latent image.
d∝ (π / 4) (λf / D) (3)
(Where d is the spot diameter on the photoreceptor, λ is the wavelength of the laser beam, f is the focal length of the fθ lens, and D is the lens diameter)
[0008]
In addition, the short wavelength LD and LED are advantageous in that the electrophotographic apparatus including the optical system can be made compact and the speed of the electrophotographic system can be increased. There is a demand for an electrophotographic photosensitive member with high sensitivity and high stability.
[0009]
However, the current electrophotographic apparatus has a resolution of about 300 to 600 dpi and is not sufficient as a photographic image. For this reason, a higher-resolution electrophotographic apparatus is desired, and development for that purpose is being carried out. In order to increase the resolution, it is effective to reduce the minimum dot diameter. To that end, image exposure means with a smaller beam diameter, an electrophotographic photosensitive member that enables a small potential latent image, and its reproducibility are improved. A developing means for developing is required.
[0010]
However, an electrophotographic apparatus that satisfies all of these has not been developed yet. In the image exposure means, conventionally, a small and inexpensive semiconductor laser (LD) and light emitting diode (LED) that are highly reliable have been used. The oscillation wavelength region of the LD that is most often used at present is in the near infrared light region around 780 to 800 nm. The beam spot diameter is about 150 to 60 μm. In order to narrow this down to a dot diameter of about 30 μm equivalent to 1200 dpi or a dot diameter of about 15 μm equivalent to 2400 dpi, an ultra-high precision optical component or a large optical member is required, and it cannot be put into practical use in terms of cost and space. There was no. In order to solve this problem, it is considered effective to shorten the wavelength of the light source, and an electrophotographic apparatus using a short wavelength laser has been proposed (Japanese Patent Laid-Open No. 5-19598). However, an ultra-high resolution image could not be obtained simply by reducing the beam diameter in this way.
[0011]
The electrophotographic photosensitive member used in the conventional electrophotographic apparatus is generally a so-called function-separated type laminated photosensitive member in which a charge generation layer is formed on a conductive support and a charge transport layer is provided thereon. It is. Furthermore, a surface protective layer may be formed on the outermost surface of the photoreceptor in order to improve mechanical or chemical durability.
[0012]
In this function-separated laminated photoconductor, when a photoconductor whose surface is charged is exposed, light passes through the charge transport layer and is absorbed by the charge generation material in the charge generation layer. The charge generating material absorbs this light and generates charge carriers. The generated charge carriers are injected into the charge transport layer and move along the electric field generated by charging to neutralize the surface charge of the photoreceptor. As a result, an electrostatic latent image is formed on the surface of the photoreceptor. Therefore, the function-separated type multilayer photosensitive member mainly has a charge generation material having absorption from the near infrared part to the visible part, and does not prevent transmission of absorbed light of the charge generation material, that is, from the visible part (yellow light region) to the ultraviolet part. Many combinations with charge transport materials with absorption are used. When such an electrophotographic photosensitive member is used, light having a very short wavelength, such as 400 to 450 nm, is absorbed by the charge transport layer and has a disadvantage that the sensitivity is lowered. In contrast, an electrophotographic apparatus using a charge transporting material that absorbs relatively little has been proposed.
[0013]
As described above, even when the charge generation layer of the electrophotographic photosensitive member can be irradiated with light having a small beam diameter, it is still difficult to form a super-resolution image. As the image formation speeds up and digitizes, the energy density of the light irradiation region increases, and the charge density generated in the charge generation layer of the electrophotographic photosensitive member increases. The charges generated at high density diffuse in the surface direction while moving through the charge transport layer to the surface of the photosensitive member, and the electrostatic latent image formed on the photosensitive member becomes large even if the angle beam diameter is reduced. Oops.
[0014]
In order to solve this problem, it is effective to reduce the thickness of the charge transport layer of the electrophotographic photosensitive member, but it is necessary to reduce it to 1/2 to 1/3 of the current state. The dot reproducibility was lowered due to potential unevenness due to the unevenness of the conductive support, which was very difficult to realize. Under such circumstances, an electrophotographic apparatus having ultra-high resolution has not yet been provided on the market.
[0015]
On the other hand, as an electrophotographic photoreceptor used in an electrophotographic apparatus, a single-layer type is known in which a photosensitive layer mainly composed of a charge generating material, a charge transporting material, and a binder is provided on a conductive support. Yes. This photoconductor is advantageous for ultra-high resolution electrophotography because charge generation due to light irradiation occurs on the surface of the photoconductor, so that the spread of the electrostatic latent image is reduced. However, the sensitivity and residual potential characteristics are inferior to those of the function-separated type multilayer photoreceptor, and there remains a problem for an electrophotographic apparatus that requires high speed.
[0016]
Also known is a reverse layer type electrophotographic photoreceptor in which a charge transport layer and a charge generation layer are laminated in this order on a conductive support. Also in this case, since the charge generation occurs on the surface of the photoreceptor, the spread of the electrostatic latent image is reduced, which is advantageous for ultra high resolution electrophotography. For example, Japanese Patent Laid-Open No. 9-240051 discloses an electrophotographic apparatus using an LD having an oscillation wavelength of 400 to 500 nm as a light source. However, this photosensitive layer structure has a fragile thin-film charge generation layer formed on the outermost surface, which makes it susceptible to mechanical and chemical hazards due to charging, development, transfer, and cleaning means. This is not practical because of the significant deterioration.
[0017]
In order to increase the lifetime, a reverse layer photoreceptor having a surface protective layer has also been proposed (Japanese Patent Laid-Open No. 1-170951). In this case, it has been aimed to provide an electrophotographic apparatus with a reduced environmental load and a reduced ozone generation amount, and has not been designed as a photoreceptor for an ultra-high resolution electrophotographic apparatus. In an image forming process in which high image quality is repeatedly performed, particularly in color image formation that requires color reproducibility and durability, an electrophotographic apparatus compatible with high durability has not been provided.
[0018]
As described above, an electrophotographic photosensitive member has been proposed that prevents the spread of an electrostatic latent image. However, the image exposure means has a beam diameter and an electrophotographic photosensitive member in an image forming process including toner development and transfer. Considering the spread of the electrostatic latent image of the body, an electrophotographic apparatus that forms an ultra-high resolution image, that is high speed and excellent in durability cannot be provided.
[0019]
In addition, when a high resolution of 400 dpi or higher is required, in an apparatus such as the present invention that uses coherent light such as a semiconductor laser or a light-emitting diode as exposure light, the film thickness deviation of the photosensitive layer of the electrophotographic photosensitive member is caused. The problem that the resulting interference fringe pattern appears in the image becomes very significant, and there is a need to solve this problem. In addition, when designing a photoconductor in consideration of high image quality, the absorbance of the charge generation layer with respect to the wavelength of the image exposure light source of the present invention for the charge generation layer in the function separation type using the existing charge generation material is When it is small, especially when the absorbance is 2.0 or less, there is a drawback that interference fringes are likely to occur. On the other hand, a method of simply increasing the thickness of the charge generation layer or increasing the concentration of the charge generation material can be considered, but there is a problem in that the charge potential is likely to decrease due to repeated use.
[0020]
Further, in Japanese Patent Laid-Open No. 3-62039, etc., countermeasures against interference fringes are taken by roughening the surface of the conductive substrate. However, if the surface is too rough, this causes a problem of poor cleaning. Furthermore, attempts have been made to suppress interference fringes by adding a dye or the like to the undercoat layer or the photosensitive layer in JP-A-7-160028. We cannot expect enough effect to achieve.
[0021]
[Problems to be solved by the invention]
Accordingly, the problem to be solved by the present invention is that the absorbance of the charge generation layer with respect to the wavelength of the exposure light source is small, particularly when an image exposure means is formed using a semiconductor laser or light emitting diode having an oscillation wavelength in the range of 400 to 450 nm. Even in such a case, it is possible to prevent interference fringes from being generated by light passing through the charge generation layer, and to form an image with an ultra-high resolution of 1200 dpi or more and 2400 dpi, and stable high image quality based on high durability. It is to provide an electrophotographic apparatus obtained.
[0022]
[Means to solve the problem]
The present invention solves such conventional drawbacks and problems. In an electrophotographic apparatus equipped with at least an electrophotographic photosensitive member, a charging unit, an image exposing unit, and a developing unit, a writing light source for the image exposing unit is provided. A semiconductor laser or a light emitting diode having an oscillation wavelength in the range of 400 to 450 nm, an electrophotographic photoreceptor is laminated on a conductive substrate in the order of a short wavelength absorption layer, a photosensitive layer and a surface protective layer; and The surface roughness of the conductive support is 0.02 μm or more and 1.5 μm or less in terms of Rz, and the surface roughness of the short wavelength light absorption layer is 0.02 μm or more and 1.5 μm or less in terms of Rz, In addition, an electrophotographic apparatus is provided in which the surface roughness of the outermost surface of the photosensitive layer is 0.02 μm or more and 1.5 μm or less in terms of Rz value.
[0023]
The photoconductor in this apparatus fulfills the requirements for ultra-high resolution image formation to achieve high image quality, and realizes stable toner development and transfer under high durability.
In other words, in order to achieve high image quality, the image exposure means and the photosensitive layer of the electrophotographic photosensitive member are devised, and when the absorbance of the charge generation layer is small with respect to the exposure light source wavelength, Absorption by the absorbing layer suppresses the generation of interference fringes and achieves high image quality. Further, the surface roughness of the conductive support is 0.02 μm or more and 1.5 μm or less in Rz value, and the surface roughness of the short wavelength light absorption layer is 0.02 μm or more and 1.5 μm or less in Rz value. In addition, the surface roughness of the outermost surface of the photosensitive layer is set to 0.02 μm or more and 1.5 μm or less in Rz value. It can be reduced.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
As a photosensitive layer of the electrophotographic photosensitive member of the present invention, typical layer configurations are shown below, but are not limited thereto. As shown in FIG. 1, a short wavelength light absorption layer 2 is formed on a conductive support 1, a charge generation layer 3 is formed, and a charge transport layer 4 is formed on the charge generation layer. A protective layer 5 is provided on top. In the case of adopting this configuration, the protective layer and the charge transport layer are required to have a sufficient transmittance for writing light. More specifically, it is desirable to exhibit a transmittance of 50% or more for monochromatic light in the 390 to 460 nm wavelength region. In addition, in order to prevent carriers generated in the charge generation layer from diffusing in the process of moving through the charge transport layer and the protective layer and inhibiting the formation of ultra-high resolution images, the thickness of the charge transport layer and the protective layer should be as small as possible. It is better to make it thinner. However, the protective layer requires 1 to 3 μm in order to achieve high durability, and the charge transport layer is appropriately 5 to 15 μm, although it depends on conditions such as development.
[0025]
The charge transport function includes a hole transport function and an electron transport function. When used for the charge transport layer, these materials may be used alone or as a mixture of both functional materials. However, if the protective layer also has a charge transport function, it should have the same function as the charge transport layer. good.
[0026]
The components of each layer will be described below.
As a conductive support, a metal film such as aluminum, nickel, copper, titanium, gold, and stainless steel, a metal drum or a metal foil, a plastic film on which aluminum, nickel, copper, titanium, gold, tin oxide, indium oxide, etc. are deposited Alternatively, a paper coated with a conductive material, a film such as plastic, or a drum may be used. Examples of materials other than the above include metals and alloys such as iron, silver, zinc, lead, tin, antimony, and indium, or oxides, carbon, conductive polymers, and the like of the metals. It is possible to use a conductive support obtained by molding or forming the conductive material on a suitable substrate by means of coating, vapor deposition, etching, plasma treatment or the like.
[0027]
The surface roughness of the conductive support is 0.02 μm to 1.5 μm in terms of Rz value. When the surface roughness of the conductive support is smaller than 0.02 μm, the scattering of the laser beam is reduced, and image defects such as interference fringes are liable to occur, or the adhesiveness with the photosensitive layer is weakened to cause peeling. It may cause image defects such as white spots. In addition, when the surface roughness exceeds 1.5 μm, potential unevenness on the surface of the photosensitive layer is caused and dot reproducibility is reduced, or pinholes due to abnormal discharge are generated in the photosensitive layer, resulting in image defects such as black spots. May occur.
[0028]
The short-wavelength light absorption layer formed on the conductive substrate of the present invention generally comprises a resin as a main component. However, considering that a resin is applied on the photosensitive layer with a solvent, these resins are generally organic. A resin having a high solvent resistance to the solvent is desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, fine powder pigments of metal oxides exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added for preventing interference fringes and optimizing resistance values. These short wavelength light absorption layers can be formed using an appropriate solvent and coating method. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can also be used. In addition, known ones can be used.
[0029]
The surface roughness of the short wavelength light absorption layer is 0.02 μm to 1.5 μm in terms of Rz value. When the surface roughness of the short wavelength light absorption layer is smaller than 0.02 μm, the scattering of the laser light becomes small and image defects such as interference fringes are likely to occur, or the adhesiveness with the charge generation layer becomes weak and peeling is caused. This causes image defects such as white spots. In addition, when the surface roughness exceeds 1.5 μm, potential unevenness on the surface of the photosensitive layer is caused and dot reproducibility is reduced, or pinholes due to abnormal discharge are generated in the photosensitive layer, resulting in image defects such as black spots. May occur.
[0030]
Moreover, the short wavelength light absorption layer contains the following short wavelength light absorption material in the binder. Examples of the short wavelength light absorbing material include so-called n-type pigments exhibiting electron transport properties, electron transport materials, chelate dyes, ultraviolet absorbers and the like.
[0031]
Examples of so-called n-type pigments that exhibit electron transporting properties include organic pigments that exhibit n-type semiconductor properties such as perylene pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, disazo pigments, and trisazo pigments. Among these, those having a high absorbance with respect to monochromatic light in the wavelength region of 390 to 460 nm are particularly preferably used.
[0032]
Examples of the electron transporting material include chloroanil, bromanyl, 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-trinitro-indeno 4H-indeno [1,2-b] thiophen-4-one, 1,3,7 -Trinitrodibenzothiophene-5,5-dioxide, oxadiazole derivatives, (2,3-diphenyl-1-indenylidene) malononitrile, dinitrobenzene, dinitroanthracene, malononitrile, thiopyran compounds, benzoquinone, diphenoquinone, stilbenequinone, etc. Quinones and their derivatives, dinitroant Sene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, dibromomaleic anhydride, and the like, and diphenoquinone derivatives and electron transport materials listed below can be preferably used. . These charge transport materials may be used alone or in combination of two or more.
[Chemical 1]
(Where R ¹ , R ² And R ^Three Represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, or a substituted or unsubstituted phenyl group, which may be the same or different. )
[0033]
Examples of chelate dyes include indoaniline dyes, azomethine dyes, phthalocyanine dyes, azo dyes, and the like, and these dyes have a group that enables chelate formation in the molecule.
[0034]
Examples of the ultraviolet absorber include known benzophenone-based, benzotriazole-based, cyanoacrylate-based, and triazine-based ultraviolet absorbers. Further, by using these in combination with HALS, a so-called light stabilizer, for example, a hindered amine light stabilizer, light deterioration can be prevented, and it can be suitably used for the purpose of the present invention.
[0035]
Moreover, 1-10 micrometers is suitable for the film thickness of a short wavelength light absorption layer. If the film thickness of the short wavelength light absorption layer is thinner than 1 μm, problems such as abnormal images due to the surface of the conductive support are likely to occur. If the film thickness exceeds 10 μm, residual potential is generated and accumulated. And the fluctuation of the photoreceptor potential is increased.
[0036]
The charge generation layer can be provided by dissolving or dispersing the charge generation material in an appropriate solvent, adding or dissolving a binder resin, if necessary, and applying and drying. Examples of the dispersion method of the charge generation layer dispersion include a ball mill, an ultrasonic wave, and a homomixer. Examples of the application means include a dipping coating method, a blade coating method, and a spray coating method.
[0037]
When a charge generating material is dispersed to form a photosensitive layer, the charge generating material preferably has an average particle diameter of 1 μm or less, preferably 0.5 μm or less, in order to improve dispersibility in the layer. In addition, it is better to be as small as possible for high image quality and small dot reproducibility. However, if the above particle size is too small, it tends to agglomerate, and the storage stability of the dispersion becomes worse due to reaggregation, the resistance of the layer increases, the crystal defects increase, and the sensitivity and repeatability decrease, Alternatively, since there is a limit in miniaturization, it is preferable to set the lower limit of the average particle diameter to 0.01 μm.
[0038]
The thickness of the charge generation layer is preferably from 0.1 to 2 μm.
[0039]
As the charge generation material, conventionally known materials can be used, and examples thereof include the following pigments. Examples of organic pigments include C.I. Pigment Blue 25 (Color Index CI 21180), C.I. Pigment Red 41 (CI 21200), C.I. Acid Red 52 (CI 45100), C.I. Basic Red 3 (CI 45210), and azo having a carbazole skeleton. Pigment (described in JP-A-53-95033), azo pigment having a distyrylbenzene skeleton (JP-A-53-133445), azo pigment having a triphenylamine skeleton (JP-A-53-132347) Azo pigments having a dibenzothiophene skeleton (described in JP-A No. 54-21728), azo pigments having an oxadiazole skeleton (described in JP-A No. 54-12742), azo pigments having a fluorenone skeleton Pigment (Japanese Patent Laid-Open No. 54-228) No. 34), azo pigments having a bisstilbene skeleton (described in JP-A No. 54-17733), azo pigments having a distyryloxadiazole skeleton (described in JP-A No. 54-2129), In addition to azo pigments having a distyrylcarbazole skeleton (described in JP-A-54-14967) and azo pigments having a benzanthrone skeleton, for example, CI Pigment Blue 16 (CI 74100), Y-type oxotitanium Phthalocyanine (JP-A 64-17066), A (β) -type oxotitanium phthalocyanine, B (α) -type oxotitanium phthalocyanine, I-type oxotitanium phthalocyanine (described in JP-A-11-21466), II-type chloro Gallium phthalocyanine (Iijima et al., The 67th Annual Meeting of the Chemical Society of Japan, 1 B4, 04 (1994)), V-type hydroxygallium phthalocyanine (Damon et al., Chemical Society of Japan, 67th Spring Annual, 1B4, 05 (1994)), X-type metal-free phthalocyanine (US Pat. No. 3,816,118) Phthalocyanine pigments such as CI Ibat Brown 5 (CI 73410), Indico pigments such as C Ibat Dye (CI 73030), Perylenes such as Argo Scarlet B (manufactured by Bayer), and Intense Scarlet R (manufactured by Bayer) And pigments. These charge generation materials may be used alone or in combination of two or more.
[0040]
Examples of the solvent used in preparing the dispersion or solution of the charge generation layer include N, N-dimethylformamide, toluene, xylene, monochlorobenzene, 1,2-dichloroethane, 1,1,1-trichloroethane, Examples include dichloromethane, 1,1,2-trichloroethane, trichloroethylene, tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl acetate, butyl acetate, and dioxane.
[0041]
Any conventionally known binder resin having good insulating properties can be used as the binder resin, and there is no particular limitation. For example, polyethylene, polyvinyl butyral, polyvinyl formal, polystyrene resin, phenoxy resin, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, Polyamide resins, silicone resins, melamine resins and other addition polymerization resins, polyaddition resins, polycondensation resins, and copolymer resins containing two or more of these resin repeating units, such as vinyl chloride-vinyl acetate In addition to insulating resins such as copolymers, styrene-acrylic copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymer resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used. These binders can be used alone or as a mixture of two or more. The amount of the binder resin is suitably 0 to 5 parts by weight, preferably 0.1 to 3 parts by weight with respect to 1 part by weight of the charge generating material.
[0042]
A conventionally well-known thing can be used as a charge transport layer. When the charge transport layer is laminated on the surface layer side from the charge generation layer, it is necessary to transmit monochromatic light in the wavelength range of 400 to 450 nm. Preferred examples in that case are as follows.
[0043]
Specific examples of the binder resin used in the charge transport layer include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-acetic acid. Vinyl copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, Thermoplastic or thermosetting resins such as epoxy resins, melamine resins, urethane resins, phenol resins, alkyd resins and the like can be mentioned.
[0044]
Among them, the binder resin is represented by the following general formula (Chemical Formula 2) and / or (Chemical Formula 3), a polyarylate resin or a polymer alloy resin of a polyarylate resin and a polycarbonate resin, or a polymer alloy of a polyarylate resin and a polyethylene terephthalate resin. Resins are preferred.
[Chemical formula 2]
[Chemical 3]
(R _Four , R _Five , R ₆ , R ₇ Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group or a halogen atom, or a substituted or unsubstituted aryl group.
X represents an aliphatic divalent group or a cycloaliphatic divalent group;
Y is a single bond, a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms, -O-, -S-, -SO-, -SO. ₂ -, -CO-, -CO-O-Z-O-CO- (wherein Z represents an aliphatic divalent group) or
[Formula 4]
(Wherein, a is an integer of 1 to 20, b is an integer of 1 to 2000, R ₈ , R ₉ Represents a substituted or unsubstituted alkyl group or aryl group. Where R ₈ And R ₉ May be the same or different. p and q represent the composition, 0.1 ≦ p ≦ 1, 0 ≦ q ≦ 0.9, and n represents the number of repeating units and is an integer of 5 to 5000).
Specific examples include the following structures, but are not limited thereto.
[0045]
[Table 1]
[0046]
[Table 2]
[0047]
In addition, the charge transport material used in the charge transport layer of the present invention includes a hole transport material and an electron transport material, and these include the following.
[0048]
Examples of hole transport materials include poly-N-carbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, imidazole There are derivatives, triphenylamine derivatives, and compounds represented by the general formula:
[0049]
[Chemical formula 5]
(Wherein R ¹ Represents a methyl group, an ethyl group, a 2-hydroxyethyl group or a 2-chloroethyl group; ² Represents a methyl group, an ethyl group, a benzyl group or a phenyl group; ^Three Represents a hydrogen atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a dialkylamino group or a nitro group. )
[0050]
[Chemical 6]
(In the formula, Ar represents a naphthalene ring, anthracene ring, pyrene ring and a substituted product thereof, or a pyridine ring, a furan ring, and a thiophene ring, and R represents an alkyl group, a phenyl group, or a benzyl group.)
[0051]
[Chemical 7]
(Wherein R ¹ Represents an alkyl group, a benzyl group, a phenyl group or a naphthyl group, R ² Represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a dialkylamino group, a diaralkylamino group or a diarylamino group, n represents an integer of 1 to 4, and n is 2 R ² May be the same or different. R ^Three Represents a hydrogen atom or a methoxy group. )
[0052]
[Chemical 8]
(Wherein R ¹ Represents an alkyl group having 1 to 11 carbon atoms, a substituted or unsubstituted phenyl group or a heterocyclic group, and R ² , R ^Three Each may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, a chloroalkyl group, or a substituted or unsubstituted aralkyl group, and R ² And R ^Three May be bonded to each other to form a heterocyclic ring containing nitrogen. R ^Four May be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group or a halogen atom. )
[0053]
[Chemical 9]
(In the formula, R represents a hydrogen atom or a halogen atom, and Ar represents a substituted or unsubstituted phenyl group, naphthyl group, anthryl group, or carbazolyl group.)
[0054]
[Chemical Formula 10]
(Wherein R ¹ Represents a hydrogen atom, a halogen atom, a cyano group, an alkoxy group having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms, Ar is
Embedded image
(R ² Represents an alkyl group having 1 to 4 carbon atoms, R ^Three Represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a dialkylamino group, n is 1 or 2, and when n is 2, R is ^Three May be the same or different and R ^Four , R ^Five Represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted benzyl group.
[0055]
Embedded image
(Wherein R is a carbazolyl group, pyridyl group, thienyl group, indolyl group, furyl group or a substituted or unsubstituted phenyl group, styryl group, naphthyl group, or anthryl group, and these substituents are dialkylamino Group, alkyl group, alkoxy group, carboxy group or ester thereof, halogen atom, cyano group, aralkylamino group, N-alkyl-N-aralkylamino group, amino group, nitro group, and acetylamino group Represents a group.)
[0056]
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(Wherein R ¹ Represents a lower alkyl group, a substituted or unsubstituted phenyl group, or a benzyl group; ² Represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a nitro group, an amino group, a lower alkyl group or an amino group substituted with a benzyl group, and n represents an integer of 1 or 2. )
[0057]
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(Wherein R ¹ Represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, R ² And R ^Three Represents an alkyl group, a substituted or unsubstituted aralkyl group or a substituted or unsubstituted aryl group, and R ^Four Represents a hydrogen atom, a lower alkyl group or a substituted or unsubstituted phenyl group, and Ar represents a substituted or unsubstituted phenyl group or naphthyl group. )
[0058]
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(Wherein n is an integer of 0 or 1, R ¹ Represents a hydrogen atom, an alkyl group or a substituted or unsubstituted phenyl group, Ar ¹ Represents a substituted or unsubstituted aryl group, R ^Five Represents an alkyl group containing a substituted alkyl group, or a substituted or unsubstituted aryl group, and A represents
Embedded image
Represents a 9-anthryl group or a substituted or unsubstituted carbazolyl group, wherein R ² Is a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or
Embedded image
(However, R ^Three And R ^Four Represents an alkyl group, a substituted or unsubstituted aralkyl group or a substituted or unsubstituted aryl group, and R ^Three And R ^Four May be the same or different, R ^Four May form a ring, and when m is 2 or more, R ² May be the same or different. ) Also, when n is 0, A and R ¹ May form a ring together. )
[0059]
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(Wherein R ¹ , R ² And R ^Three Represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom or a dialkylamino group, and n represents 0 or 1. )
[0060]
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(Wherein R ¹ And R ² Represents an alkyl group including a substituted alkyl group, or a substituted or unsubstituted aryl group, and A represents a substituted amino group, a substituted or unsubstituted aryl group, or an allyl group. )
[0061]
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(In the formula, X represents a hydrogen atom, a lower alkyl group or a halogen atom, R represents an alkyl group containing a substituted alkyl group, or a substituted or unsubstituted aryl group, and A represents a substituted amino group or a substituted or unsubstituted group. Represents an aryl group.)
[0062]
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(Wherein R ¹ Represents a lower alkyl group, a lower alkoxy group or a halogen atom, R ² , R ^Three May be the same or different and each represents a hydrogen atom, a lower alkyl group, a lower alkoxy group or a halogen atom, and l, m and n each represents an integer of 0 to 4. )
[0063]
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(Wherein R ¹ , R ^Three And R ^Four Is a hydrogen atom, amino group, alkoxy group, thioalkoxy group, aryloxy group, methylenedioxy group, substituted or unsubstituted alkyl group, halogen atom or substituted or unsubstituted aryl group, R ² Represents a hydrogen atom, an alkoxy group, a substituted or unsubstituted alkyl group or a halogen atom. However, R ¹ , R ² , R ^Three And R ^Four Except when all are hydrogen atoms. K, l, m and n are integers of 1, 2, 3 or 4, and when each is an integer of 2, 3 or 4, the R ¹ , R ² , R ^Three And R ^Four May be the same or different. )
[0064]
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(In the formula, Ar represents a condensed polycyclic hydrocarbon group having 18 or less carbon atoms which may have a substituent, and R ¹ And R ² Represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, or a substituted or unsubstituted phenyl group, which may be the same or different. n represents an integer of 1 or 2. )
[0065]
Embedded image
(In the formula, Ar represents a substituted or unsubstituted aromatic hydrocarbon group, and A represents
Embedded image
(However, Ar represents a substituted or unsubstituted aromatic hydrocarbon group, R ¹ And R ² Represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. )
[0066]
Embedded image
(In the formula, Ar represents a substituted or unsubstituted aromatic hydrocarbon group, R represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. N is 0 or 1, m is When 1 or 2 and n = 0 and m = 1, Ar and R may form a ring together.)
[0067]
Examples of the compound represented by the general formula 5 include 9-ethylcarbazole-3-aldehyde-1-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde-1-benzyl-1-phenylhydrazone, And 9-ethylcarbazole-3-aldehyde-1,1-diphenylhydrazone.
[0068]
Examples of the compound represented by the general formula 6 include 4-diethylaminostyryl-β-aldehyde-1-methyl-1-phenylhydrazone, 4-methoxynaphthalene-1-aldehyde-1-benzyl-1-phenylhydrazone, and the like. There is.
[0069]
Examples of the compound represented by the general formula 7 include 4-methoxybenzaldehyde-1-methyl-1-phenylhydrazone, 2,4-dimethoxybenzaldehyde-1-benzyl-1-phenylhydrazone, and 4-diethylaminobenzaldehyde-1. , 1-diphenylhydrazone, 4-methoxybenzaldehyde-1- (4-methoxy) phenylhydrazone, 4-diphenylaminobenzaldehyde-1-benzyl-1-phenylhydrazone, 4-dibenzylaminobenzaldehyde-1,1-diphenylhydrazone, etc. There is.
[0070]
Examples of the compound represented by the general formula 8 include 1,1-bis (4-dibenzylaminophenyl) propane, tris (4-diethylaminophenyl) methane, 1,1-bis (4-dibenzylaminophenyl). ) Propane, 2,2-dimethyl-4,4-bis (diethylamino) -triphenylmethane, and the like.
[0071]
Examples of the compound represented by the general formula 9 include 9- (4-diethylaminostyryl) anthracene and 9-bromo-10- (4-diethylaminostyryl) anthracene.
[0072]
Examples of the compound represented by the general formula 10 include 9- (4-dimethylaminobenzylidene) fluorene and 3- (9-fluorenylidene) -9-ethylcarbazole.
[0073]
Examples of the compound represented by the general formula 12 include 1,2-bis (4-diethylaminostyryl) benzene and 1,2-bis (2,4-dimethoxystyryl) benzene.
[0074]
Examples of the compound represented by the general formula 13 include 3-styryl-9-ethylcarbazole and 3- (4-methoxystyryl) -9-ethylcarbazole.
[0075]
Examples of the compound represented by the general formula 14 include 4-diphenylaminostilbene, 4-dibenzylaminostilbene, 4-ditolylaminostilbene, 1- (4-diphenylaminostyryl) naphthalene, 1- (4- Diethylaminostyryl) naphthalene.
[0076]
Examples of the compound represented by the general formula 15 include 4′-diphenylamino-α-phenylstilbene and 4′-bis (4-methylphenyl) amino-α-phenylstilbene.
[0077]
Examples of the compound represented by the general formula 18 include 1-phenyl-3- (4-diethylaminostyryl) -5- (4-diethylaminophenyl) pyrazoline.
[0078]
Examples of the compound represented by the general formula 19 include 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole, 2-N, N-diphenylamino-5- (4- And diethyl (aminophenyl) -1,3,4-oxadiazole and 2- (4-dimethylaminophenyl) -5- (4-diethylaminophenyl) -1,3,4-oxadiazole.
[0079]
Examples of the compound represented by the general formula 20 include 2-N, N-diphenylamino-5- (N-ethylcarbazol-3-yl) -1,3,4-oxadiazole, 2- (4 -Diethylaminophenyl) -5- (N-ethylcarbazol-3-yl) -1,3,4-oxadiazole.
[0080]
Examples of the benzidine compound represented by the general formula 21 include N, N-diphenyl-N, N-bis (3-methylphenyl)-[1,1-biphenyl] -4,4-diamine, 3,3. -Dimethyl-N, N, N, N-tetrakis (4-methylphenyl)-[1,1-biphenyl] -4,4-diamine.
[0081]
Examples of the biphenylylamine compound represented by the general formula 22 include 4-methoxy-N, N-diphenyl- [1,1-biphenyl] -4-amine, 4-methyl-N, N-bis (4 -Methylphenyl)-[1,1-biphenyl] -4-amine, 4-methoxy-N, N-bis (4-methylphenyl)-[1,1-biphenyl] -4-amine, N, N-bis (3,4-dimethylphenyl)-[1,1-biphenyl] -4-amine and the like.
[0082]
Examples of the triarylamine compound represented by the general formula 23 include 1-diphenylaminopyrene, 1-di (p-tolylamino) pyrene, N, N-di (p-tolyl) -1-naphthylamine, N, N-di (p-tolyl) -1-phenanthrylamine, 9,9-dimethyl-2- (di-p-tolylamino) fluorene, N, N, N, N-tetrakis (4-methylphenyl) -phenanthrene -9,10-diamine, N, N, N, N-tetrakis (3-methylphenyl) -m-phenylenediamine and the like.
[0083]
Examples of the diolefin aromatic compound represented by the general formula 24 include 1,4-bis (4-diphenylaminostyryl) benzene and 1,4-bis [4-di (p-tolyl) aminostyryl. There are benzene and the like. Examples of the styrylpyrene compound represented by the general formula 23 include 1- (4-diphenylaminostyryl) pyrene and 1- [4-di (p-tolyl) aminostyryl] pyrene.
[0084]
Examples of polymer charge transport materials include poly-N-carbazole derivatives, poly-γ-carbazolylethyl glutamate derivatives, pyrene-formaldehyde condensate derivatives, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, imidazole derivatives, acetophenone derivatives ( JP-A-7-325409), distyrylbenzene derivatives, diphenethylbenzene derivatives (described in JP-A-9-127713), α-phenylstilbene derivatives (described in JP-A-9-297419), butadiene Derivatives (described in JP-A-9-80783), hydrogenated butadiene (described in JP-A-9-80784), diphenylcyclohexane derivatives (described in JP-A-9-80772), distyryltriphenylamine derivatives ( JP-A-9-222740), diphenyl distyrylbenzene derivatives (described in JP-A-9-265197 and 9-265201), stilbene derivatives (described in JP-A-9-212877), m- Phenylenediamine derivatives (described in JP-A-9-304956 and JP-A-9-304957), resorcin derivatives (described in JP-A-9-329907), triarylamine derivatives (JP-A 64-9964, JP 7-199503, JP-A-8-176293, JP-A-8-208820, JP-A-8-253568, JP-A-8-269446, JP-A-3-221522, JP-A-4-11627, JP-A-4-11627. 183719, JP-A-4-124163, JP-A-4-320420, JP-A-4-316543. , JP-A-5-310904, JP-A-7-56374, JP-A 8-62864 Patent JP-U.S. Patent No. 5,428,090, the specification Nos. 5,486,439) and the like.
[0085]
Examples of these polymer type charge transport materials (P1 to P27) are listed, but the form is limited to this even if the form is a homopolymer, a random copolymer, an alternating copolymer, or a block copolymer. It is not a thing.
[0086]
[Table 3]
[0087]
[Table 4]
[0088]
[Table 5]
[0089]
[Table 6]
[0090]
[Table 7]
[0091]
[Table 8]
[0092]
These charge transport materials may be used alone or in combination of two or more.
The amount of the charge transport material is 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. As the solvent used for forming the charge transport layer, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used.
[0093]
Since the surface protective layer is formed above the charge transport layer, it is naturally necessary to absorb as little as possible monochromatic irradiation light in the wavelength range of 400 to 450 nm. The materials used are ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, polybutylene terephthalate. , Polycarbonate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinylidene chloride, Resins such as epoxy resins can be used.
[0094]
In addition to the protective layer, fluorine resins such as polytetrafluoroethylene, silicone resins, and inorganic fillers or organic fillers having high hardness can be added to these resins for the purpose of improving wear resistance. The average particle size of these fillers is 0.02 μm to 3 μm, preferably 0.05 to 1 μm. If the particle size is smaller than this, the wear resistance of the surface protective layer becomes weak, and a long-life image forming apparatus cannot be obtained. When the particle size is large, resolution is lowered due to light scattering.
[0095]
Specific examples of fillers include titanium oxide, tin oxide, zinc oxide, zirconium oxide, indium oxide, silicon nitride, calcium oxide, barium sulfate, ITO, silica, colloidal silica, alumina, carbon black, fluorine resin fine powder, poly Any one or a mixture of siloxane-based resin fine powder and polymer charge transport material fine powder can be used.
[0096]
These fillers may be surface-treated with an inorganic substance or an organic substance for reasons such as improving dispersibility and modifying surface properties. In general, those treated with a silane coupling agent as a water repellency treatment, those treated with a fluorinated silane coupling agent, those treated with a higher fatty acid treatment or a polymer material, and the like are used as inorganic treatments. Are treated with alumina, zirconia, tin oxide and silica.
[0097]
The filler is pulverized or dispersed as it is together with a binder resin and / or a charge transport material and a dispersion solvent, and is applied as a photosensitive layer. The filler content in the formed surface protective layer is 5 to 50% by weight, preferably 10 to 40% by weight, and if it is 10% by weight or less, it is not sufficient in terms of wear resistance, and 40% by weight or more. If so, the transparency of the surface protective layer is impaired and sensitivity is lowered. The average particle size is preferably pulverized and dispersed to 0.02 to 3.0 μm, preferably 0.05 to 1.0 μm. If the particle size is large, the cueing cleaning blade will be damaged on the surface, resulting in poor cleaning, and the image quality will deteriorate.
[0098]
Dispersing solvents include methyl ethyl ketone, acetone, methyl isobutyl ketone, cyclohexanone ketones, ethers such as dioxane, tetrahydrofuran and ethyl cellosolve, aromatics such as toluene and xylene, halogens such as chlorobenzene and dichloromethane, ethyl acetate and butyl acetate Esters such as are used. When adding a pulverization process, a ball mill, a sand mill, a vibration mill or the like is used.
[0099]
Further, in the photosensitive layer and / or protective layer, for the purpose of improving the charging property, a phenol compound, a hydroquinone compound, a hindered phenol compound, a hindered amine compound, a compound in which a hindered amine and a hindered phenol are present in the same molecule. Etc. can be added.
[0100]
Furthermore, you may add a plasticizer and a leveling agent. As the plasticizer, those used as general plasticizers such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is suitably about 0 to 30% by weight based on the binder resin. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain are used, and the amount used is 0 to 0 with respect to the binder resin. 1% by weight is suitable.
[0101]
The contact angle with respect to pure water on the surface of the electrophotographic photoreceptor of the present invention is preferably 90 ° or more. More preferably, it is 95 ° or more. When the contact angle with respect to pure water is 90 ° or more, the surface energy of the photoreceptor is reduced. When the contact angle with respect to pure water on the surface of the photoreceptor is less than 90 °, it is easy to adhere a fallen product resulting from the charged product, toner or paper due to repeated use by the electrophotographic process, and due to poor cleaning or a decrease in surface resistance. It tends to cause deterioration of the latent image (image flow). On the other hand, if the contact angle with pure water is too large, the development stability of the photosensitive member and the toner will be insufficient, so 140 ° or less is preferable.
[0102]
In order to increase the contact angle with respect to pure water on the surface of the electrophotographic photosensitive member to 90 ° or more, for example, a polymer having a silicone structure such as a dimethylsilicone portion or a methylphenylsilicone portion, a perfluoroalkyl structure, or a long-chain alkyl structure is used. use. Alternatively, fluorine resin fine powder, polysiloxane resin fine powder, silicone oil, wax having an ester group, higher fatty acid and the like are added to the photoreceptor. Alternatively, it can be achieved by applying or supplying these. Furthermore, these methods may be used in combination to enhance the effect.
[0103]
Here, as described above, F / C and Si / C mean that a material having a silicone structure or a perfluoroalkyl structure is extremely effective in increasing the contact angle and lowering the surface energy of the photoreceptor. It is an effective material. Therefore, by defining this value, adverse effects such as poor cleaning can be prevented. Here, if F / C and Si / C are smaller than 0.01, the surface energy is high and the effect is not sufficient, and if it is larger than 1.00, the development stability of the toner becomes insufficient, which is not preferable. . Here, XPS (X-ray photoelectron spectroscopy), which is a method for measuring the atomic ratio, is a PHI 1600S type, using MgKα (200 W) as an X-ray source, and measuring an area of 0.8 × 2 mm, It calculated | required as an average value of 10 places.
[0104]
Various cross-linking reactions known in the field of materials can be used to form the surface protective layer with a layer made of at least a curable resin. As the reaction, radical polymerization, ionic polymerization, thermal polymerization, photopolymerization, radiation polymerization, plasma CVD method, photo CVD method and the like are well known. For example, JP-A-2-132456, JP-A-11-288121, JP-A-11-265085, JP-A-11-212291, JP-A-2000-66433, and the like.
[0105]
In order to have a charge transport function together, a material having a charge transport function or a polymer charge transport material may be subjected to a crosslinking reaction. For these, for example, the materials and methods described in JP 2000-147814 A, JP 2000-147804 A, JP 2000-122322 A, and the like can be used.
[0106]
In order to realize a cured protective layer having a low surface energy, for example, a silicone structure, a perfluoroalkyl structure, or a long-chain alkyl structure by a method disclosed in JP-A-11-95474 and JP-A-2000-131860. A material having the above may be subjected to a crosslinking reaction.
[0107]
As a mechanism for controlling the wear resistance of the photoreceptor, JP-A-8-20226, JP-A-11-212398, JP-A-11-219087, JP-A-11-311928, JP-A-2000-047523. There are methods described in Japanese Patent Laid-Open No. 2000-09838, Japanese Patent Laid-Open No. 2000-147946, and the like. Among these, zinc stearate, silicone oil, fluorine-based oil, fluorine-containing polymer, etc. are exemplified as lubricants, and these lubricants are applied to and / or supplied to the photoreceptor surface to form an ultrathin film. Thus, an electrophotographic apparatus having low surface energy, low wear and high image quality is provided.
[0108]
As the charging means, known means such as a corotron, a scorotron, a solid state charger (solid state charger), and a charging roller are used. Contact the surface of the body to be charged or the method of charging the surface of the body to be charged by directly applying the surface of the conductive roller to the surface of the body to be charged (including the surface having a protective layer) and applying a voltage to the roller. A method is used in which a charging member is brought into contact and a surface of a member to be charged is charged by applying a voltage to the contact charging member.
[0109]
As the image exposure means, a semiconductor laser or light emitting diode having an oscillation wavelength in the range of 400 to 450 nm is used. When a semiconductor laser is used, the main configuration of the image exposure means includes a semiconductor laser (LD), an aperture, a collimating lens, a main CYL, a sub CYL, a polygon mirror, a scanning lens 1, a scanning lens 2, and a mirror. The LD is controlled at an image frequency of 65 MHz or more, preferably 100 MHz or more, and more preferably 130 MHz or more. Further, temperature compensation control is performed, and the rotational speed of the polygon mirror is 50 Krpm or more, preferably 60 Krpm or more. The light source is preferably used as a multi-beam, and at least 2 channels, preferably 4 channels or more are used.
[0110]
A conventionally known developing device can be used as the developing means. For example, a contact development method and a non-contact development method can be raised. The non-contact development method refers to a method in which an image is developed by applying an electric field with a gap larger than the thickness of the developer layer between the electrostatic image carrier and the developer carrier. The development voltage may be DC, AC, or DC + AC. AC development refers to a method in which an electrostatic latent image holding member and a developer carrying member are made to face each other and an alternating electric field is applied for visualization. At that time, the average particle diameter of the toner used is 4 to 8 μm, and it may be a pulverized toner or a polymerized toner. In the case of a polymerized toner, a toner produced by a method in which a composition containing a monomer and a colorant, or a composition containing a prepolymer and a colorant is polymerized in a liquid medium, or if necessary, the toner is physically or It represents chemically processed toners and developers containing these toners.
[0111]
Next, the electrophotographic method and the electrophotographic apparatus of the present invention will be described in detail with reference to the drawings.
[0112]
FIG. 2 is a schematic diagram for explaining the electrophotographic apparatus of the present invention, and modifications as described below also belong to the category of the present invention.
In FIG. 2, the photoreceptor 1 is provided with a photosensitive layer in which a short wavelength light absorption layer, a charge generation layer, a charge transport layer, and a surface protective layer are sequentially laminated on a conductive support. The photosensitive member 1 has a drum shape, but may be a sheet shape or an endless belt shape. For the charging charger 3, the pre-transfer charger 7, the transfer charger 10, the separation charger 11, and the pre-cleaning charger 13, known means such as a corotron, a scorotron, a solid state charger, and a charging roller are used. It is done.
[0113]
As the transfer means, the above charger can be generally used. However, as shown in the figure, a combination of a transfer charger and a separation charger is effective.
[0114]
For the image exposure unit 5, a semiconductor laser having an oscillation wavelength in the range of 400 to 450 nm is used. In addition, as a light source such as the charge eliminating lamp 2, general light emitting materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) should be used. Can do. Various types of 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 to irradiate only light in a desired wavelength range.
[0115]
Such a light source or the like irradiates the photosensitive member with light by providing a transfer process, a static elimination process, a cleaning process, or a pre-exposure process using light irradiation in addition to the process shown in FIG.
[0116]
The toner developed on the photoreceptor 1 by the developing unit 6 is transferred to the transfer paper 9, but not all is transferred, and some toner remains on the photoreceptor 1. Such toner is removed from the photoreceptor by the fur brush 14 and the blade 15. Cleaning may be performed only with a cleaning brush, and a known brush such as a fur brush or a mag fur brush is used as the cleaning brush.
[0117]
A known method is applied to the developing unit, and a known method is also used for the charge eliminating unit.
[0118]
FIG. 3 shows another example of an electrophotographic process according to the present invention. The photosensitive member 21 has the photosensitive layer of the present invention and is driven by driving rollers 22a and 22b and charged by a charger 23, image exposure by a light source 24, development (not shown), transfer using a charger 25, light source The pre-cleaning exposure by 26, the cleaning by the brush 27, and the charge removal by the light source 28 are repeated. In FIG. 3, the photosensitive member 21 (of course, the support is translucent in this case) is irradiated with pre-cleaning exposure light from the support side.
[0119]
The above illustrated electrophotographic process is illustrative of an embodiment of the present invention, and of course other embodiments are possible. For example, in FIG. 3, the pre-cleaning exposure is performed from the support side, but this may be performed from the photosensitive layer side, or image exposure and neutralization light irradiation may be performed from the support side.
[0120]
On the other hand, the light irradiation process is illustrated as image exposure, pre-cleaning exposure, and static elimination exposure. In addition, a pre-transfer exposure, a pre-exposure of image exposure, and other known light irradiation processes are provided to light the photosensitive member. Irradiation can also be performed.
[0121]
The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. The process cartridge is a unit in which at least one of a photosensitive member, a charging unit, a developing unit, and a cleaning unit is integrally formed and is detachable from the apparatus main body. There are many shapes and the like of the process cartridge, but a general example is shown in FIG.
[0122]
【Example】
Hereinafter, although an example is given and the present invention is explained, the present invention is not restricted by an example. All parts are parts by weight.
[0123]
Example 1
1.5 parts of oil-free alkyd resin (Dainippon Ink Chemical Co., Ltd .: Beckolite M6401), 1 part of melamine resin (Dainippon Ink Chemical Co., Ltd .: Super Becamine G-821), 3 parts of dibromoanthanthrone, 2-butanone 22.5 parts of the mixture was placed in a ball mill pot, and an alumina ball having a diameter of 10 mm was used, and ball milling was performed for 48 hours to prepare a short wavelength light absorption layer coating solution. This coating solution is applied onto an aluminum cylinder having a surface roughness Rz value of 0.5 μm cut at a feed rate of 0.2 mm / rev, dried at 130 ° C. for 20 minutes, and a short wavelength light having a film thickness of about 2.5 μm. An absorbent layer was obtained. The surface roughness of this short-wavelength light absorption layer was measured using a surface roughness profile measuring device Surfcom 570A manufactured by Tokyo Seimitsu Co., Ltd. at a measurement distance of 2.5 mm and a scanning speed of 0.3 mm / sec. .3.
[0124]
Next, 500 parts of a 0.5% tetrahydrofuran solution of 7.5 parts of a bisazo compound represented by the following structural formula (a) and 2.5 parts of a polyester resin (Toyobo Co., Ltd., Byron 200) were pulverized and mixed in a ball mill. The obtained dispersion was applied onto the short wavelength light absorption layer and dried naturally to form a charge generation layer.
Embedded image
[0125]
Next, as a charge transport material, 7 parts of a charge transport material represented by the following structural formula (b) and 10 parts of polycarbonate resin (manufactured by Teijin Ltd., Panlite C-1400) are dissolved in tetrahydrofuran, and this charge transport layer coating solution Was applied on the charge generation layer and dried at 80 ° C. for 2 minutes and then at 130 ° C. for 20 minutes to form a charge transport layer having a thickness of about 14 μm.
Embedded image
[0126]
Next, 8 parts of the polymer type charge transport material represented by the exemplary compound (P9) and 3 parts of polytetrafluoroethylene particles (average primary particle size 0.3 μm) are dissolved in 40 parts of THF and 140 parts of cyclohexanone, and this protection is performed. A layer coating solution was applied onto the charge transport layer and dried at 80 ° C. for 2 minutes and then at 130 ° C. for 20 minutes to form a protective layer having a thickness of 2 μm to prepare a photoreceptor. The surface roughness of the outermost surface of this protective layer was Rz value 0.6.
[0127]
With respect to this photoreceptor, the contact angle with pure water was measured by a droplet method using a contact angle meter CA-W type (manufactured by Kyowa Interface Science Co., Ltd.). The contact angle was 110 degrees.
Further, regarding the separately prepared photoreceptor, the ratio of surface elements by XPS was measured, and as a result, F / C = 0.11.
[0128]
An electrophotographic photoreceptor thus obtained, a charging roller as charging means, a semiconductor laser having an oscillation wavelength of 405 nm as a light source as image exposure means, an optical system whose beam system can be adjusted by an aperture, a two-component developing unit and a pattern as developing means An isolated dot obtained with a 30 μm beam system was formed on a photosensitive member by an imaging experiment machine equipped with a generator, transferred to an adhesive tape, read by a CCD camera, and image analysis was performed. The initial charging potential of the photoreceptor was −600 V, and magnetic toner having an average particle diameter of 6 μm was used. The shape and reproducibility of the isolated dots were evaluated visually.
[0129]
Further, the above-described electrophotographic photosensitive drum is mounted on the electrophotographic process shown in FIG. 2 (however, the image exposure light source is an LD having a light emission at 405 nm (image writing by a polygon mirror)), and an image of a test chart. The evaluation was conducted at the beginning and after printing 10,000 sheets, and the occurrence of abnormal images and the like were observed. The results are shown in Table 9.
[0130]
(Example 2)
In place of the dibromoanthanthrone used in Example 1, an electron transport material represented by the following structural formula (c) was used, and a short wavelength light absorption layer and a charge generation layer were formed on an aluminum cylinder in the same manner as in Example 1. A charge transport layer was formed.
[0131]
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[0132]
Next, 3 parts of a charge transport material represented by the following structural formula (d), 0.03 part of distearyl-3,3′-thiodipropionate as an antioxidant, polystyrene resin (manufactured by Sanyo Chemical Industries, Ltd .: SBM-700) ) A protective layer coating solution consisting of 5 parts, 2 parts of titanium oxide fine particles (CR97 manufactured by Ishihara Sangyo Co., Ltd.) as filler, 40 parts of THF and 140 parts of cyclohexanone was applied onto the charge transport layer, and a protective layer having a thickness of about 2.5 μm To form a photosensitive drum. The surface roughness of the outermost surface of this protective layer was Rz value 0.8. The electrophotographic photoreceptor thus obtained was evaluated in the same manner as in Example 1.
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[0133]
(Example 3)
Instead of the electron transport material used in Example 2, a short wavelength light absorption layer and a charge generation layer are formed on an aluminum cylinder as in Example 2 except that an electron transport material represented by the following structural formula (e) is used. A charge transport layer was formed.
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[0134]
Next, 3 parts of a charge transport material represented by the structural formula (f), 2 parts of carbon fluoride particles (average primary particle size 0.2 μm), 5 parts of polycarbonate resin (Teijin Panlite TS-2050) Then, this protective layer coating solution of 2 parts of titanium oxide fine particles (CR97 manufactured by Ishihara Sangyo Co., Ltd.), 40 parts of THF and 140 parts of cyclohexanone as a filler is applied on the charge transport layer to form a protective layer having a thickness of about 1.5 μm. A photosensitive drum was prepared.
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[0135]
With respect to this photoreceptor, the contact angle with pure water was measured by a droplet method using a contact angle meter CA-W type (manufactured by Kyowa Interface Science Co., Ltd.). The contact angle was 113 degrees. The surface roughness of the outermost surface of this protective layer was Rz value 0.7. Further, as a result of measuring the ratio of surface elements by XPS on a separately prepared photoreceptor, F / C = 0.1. The electrophotographic photoreceptor thus obtained was evaluated in the same manner as in Example 1.
[0136]
(Examples 4-6, Comparative Examples 1-4)
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the surface roughness of the aluminum plate support was changed as shown in Table 9 by changing the cutting conditions or mirror finishing. The results are shown in Table 9.
[0137]
(Comparative Examples 5 and 6)
Evaluations were made in the same manner except that the photoconductors of Examples 1 and 2 were mounted on the electrophotographic process shown in FIG. 2 and a semiconductor laser having an oscillation wavelength of 780 nm was used as the image exposure light source. The results are shown in Table 9.
[Table 9]
[0138]
(Comparative Examples 7 and 8)
Evaluation was performed in the same manner except that the average particle diameter of the toner used in Example 2 was changed. The results are shown in Table 10.
[Table 10]
[0139]
From these results, the electrophotographic photosensitive member and the electrophotographic apparatus of the present invention are excellent in dot reproducibility, and furthermore, a stable image can be obtained even by repeated use, and the occurrence of moire can be suppressed by the short wavelength light absorption layer. Recognize. Further, it is understood that a photoreceptor having a protective layer containing a filler and a surface having a low surface energy are excellent in abrasion resistance and provide a stable ultra-high resolution image.
[0140]
【The invention's effect】
As described above, according to the present invention, micro dots can be formed with high reproducibility, and because of excellent printing durability, ultra-high resolution images of 1200 dpi or 2400 dpi can be formed, and highly durable parts replacement is possible. It is possible to provide an electrophotographic photosensitive member, an electrophotographic apparatus, and a process cartridge that are capable of being charged with a low polarity.
[Brief description of the drawings]
FIG. 1 is a diagram showing a layer structure of an example of an electrophotographic photosensitive member of the present invention.
FIG. 2 is a diagram for explaining an electrophotographic apparatus of the present invention.
FIG. 3 is a diagram for explaining another electrophotographic apparatus of the present invention.
FIG. 4 is a view for explaining a process cartridge of the present invention.
[Explanation of symbols]
(In Fig. 1)
1 Conductive support
2 Short wavelength light absorption layer
3 Charge generation layer
4 Charge transport layer
5 Protective layer

Claims (12)

On a conductive support and have contact to the electrophotographic photosensitive member having a photosensitive layer, a conductive support a photosensitive layer through the short-wavelength light-absorbing layer on the body, Ri name by laminating a surface protective layer in this order,
The short-wavelength light absorption layer has absorption in a writing light source wavelength region of at least 400 to 450 nm,
The short wavelength light absorption layer contains at least one selected from dibromoanthanthrone, a compound represented by the following structural formula (c), and a compound represented by the following structural formula (e),
The surface roughness of the conductive support is 0.02 μm or more and 1.5 μm or less in terms of Rz, the surface roughness of the short wavelength light absorption layer is 0.02 μm or more and 1.5 μm or less in terms of Rz, and An electrophotographic photoreceptor, wherein the outermost surface of the photosensitive layer has an Rz value of 0.02 μm or more and 1.5 μm or less .
The electrophotographic photoreceptor is composed of a laminated electrophotographic photoreceptor in which a charge generation layer, a charge transport layer, and a surface protective layer are sequentially provided on a conductive support through a short wavelength light absorption layer. Item 2. The electrophotographic photosensitive member according to Item 1. 3. The electrophotographic photoreceptor according to claim 2, wherein the surface protective layer is composed of a layer comprising at least a filler and a binder resin. 3. The electrophotographic photosensitive member according to claim 2, wherein the surface protective layer comprises at least a layer comprising a filler and a charge transport material. Filler is titanium oxide, tin oxide, zinc oxide, zirconium oxide, indium oxide, silicon nitride, calcium oxide, barium sulfate, silica, colloidal silica, alumina, carbon black, fluorine resin fine powder, polysiloxane resin fine powder, polyethylene The electrophotographic photosensitive member according to claim 3 or 4, wherein the electrophotographic photosensitive member is at least one selected from a resin-based fine powder and a graft copolymer having a core-shell structure. 3. The electrophotographic photosensitive member according to claim 2, wherein the surface protective layer comprises at least a layer made of a polymer type charge transport material. 3. The electrophotographic photosensitive member according to claim 2, wherein the surface protective layer is composed of a layer made of at least a curable resin. 3. The electrophotographic photosensitive member according to claim 2, wherein a contact angle of the surface protective layer with respect to pure water is 90 degrees or more. 9. The electrophotographic photosensitive member according to claim 2, wherein a film thickness from the photosensitive layer to the surface protective layer is 4 μm or more and 15 μm or less. An electrophotographic photosensitive member according to any one of claims 1 to 9, and at least one means selected from a charging means, an image exposure means, a developing means, a transfer means, and a cleaning means, are integrally formed to form an electrophotographic A process cartridge characterized by being detachable from the apparatus main body. Image exposure means, development means, transfer means, and cleaning using at least the electrophotographic photosensitive member according to claim 1 and a charging means, a semiconductor laser or a light emitting diode having an oscillation wavelength in the range of 400 to 450 nm. An electrophotographic apparatus comprising the means. 12. The electrophotographic apparatus according to claim 11, wherein the shorter one of the beam diameters of the writing light source in the main scanning direction and the sub-scanning direction is 10 to 40 [mu] m.