JP2008152241A - Photoconductor, image forming method, image forming apparatus, and process cartridge - Google Patents

Abstract

An object of the present invention is to provide a photoconductor capable of forming an image with few defects even when used for a long period of time. Another object of the present invention is to provide an image forming method using the photoreceptor, an image forming apparatus having the photoreceptor, and a process cartridge.
A photoconductor includes a conductive support and at least an intermediate layer, a charge generation layer, and a charge transport layer, which are sequentially laminated. The intermediate layer is made of an inorganic semiconductor, and the charge generation layer includes a charge generation material. The electron affinity of the inorganic semiconductor is smaller than the ionization potential of the charge generation material.
[Selection figure] None

Description

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

  In recent years, from the viewpoints of saving office space, expanding business opportunities, etc., high speed, downsizing, colorization, high image quality, and easy maintenance are desired for electrophotographic apparatuses. These are regarded as problems to be solved by developing an electrophotographic photosensitive member because they are related to improvement in characteristics and durability of the electrophotographic photosensitive member. From the viewpoint of improving ease of maintenance, there is a reduction in the replacement frequency of the electrophotographic photosensitive member. This is to reduce the main image defects derived from the electrophotographic photosensitive member as much as possible over a long period of time, which is nothing but the extension of the life of the electrophotographic photosensitive member. In addition, in recent years, there have been many reports on development relating to extending the life of electrophotographic photosensitive members because they are related to the improvement in the quality of output images over a long period of time.

  In order to extend the life of the electrophotographic photosensitive member, it is essential to improve durability against various hazards that the electrophotographic photosensitive member receives. For example, as a means for cleaning the toner remaining on the photosensitive member, a method of contacting an elastic member, that is, a so-called blade cleaning method is mainly used. Since this method has a large toner removing ability in a small space, it is very effective for miniaturization of the electrophotographic apparatus. However, since the elastic member is directly brought into contact with the electrophotographic photosensitive member and rubbed, the electrophotographic photosensitive member is used. The mechanical hazard to the body is very large. For this reason, in an electrophotographic apparatus to which the present cleaning method is applied, wear of the electrophotographic photosensitive member often becomes a problem, and it is known that a high hardness protective layer is laminated in order to extend the life. (See Patent Documents 1 to 5).

  Examples of the hazard to the electrophotographic photosensitive member other than the mechanical hazard include a hazard due to charges passing through the photosensitive layer, the charge generation layer, the charge transport layer, the intermediate layer and the like. Since most of the electrophotographic photoreceptors that are currently widely used are composed of organic materials, the organic materials gradually change in quality due to the passage of electric charges, and charge traps are generated in the layers. Degradation of electrophotographic characteristics such as degradation of properties occurs. In particular, it is known that a decrease in chargeability has a great influence on the image quality of an output image, and causes serious problems such as a decrease in image density, background contamination, and image homogeneity during continuous output.

  The decrease in chargeability is considered to be caused by the injection of charges from the conductive substrate to the photosensitive layer, the charge generation layer, the charge transport layer, etc., and the generation of charge traps in the intermediate layer. For example, in the case of a photoreceptor having a laminated type photosensitive layer, the surface of the charge transport layer is negatively charged by a charger. At that time, when a positive charge is injected from the conductive substrate to the photosensitive layer, Since the applied charge is canceled, a desired charging potential cannot be obtained. When this decrease in chargeability occurs in a micro area, it causes problems such as background smearing in the output image. Further, when it occurs in the entire area of the photoconductor, the image density is lowered. Further, when charge traps occur in the intermediate layer, it is considered that negative charges generated in the charge generation layer are trapped in the intermediate layer, thereby causing a decrease in chargeability, an increase in exposed portion potential, and the like.

  As an improvement measure against the decrease in chargeability, for example, an intermediate layer between a conductive support and a photosensitive layer is known as an insulating layer (see Patent Documents 6 and 7). Thereby, it is possible to suppress the charge injection from the conductive support to the photosensitive layer, but on the other hand, it is difficult to flow the charge generated in the photosensitive layer to the conductive support. Causes it to rise.

Further, a method is known in which an intermediate layer made of an organic material (and inorganic fine particles) contains an acceptor material or a donor material to transport a charge having a desired polarity (see Patent Document 8). As a result, it is possible to suppress the occurrence of charge traps in the intermediate layer and improve the decrease in chargeability. However, since the acceptor material or donor material is made of an organic material, it deteriorates due to the passage of charge in the intermediate layer. To do. Further, most of OPCs are photoreceptors having a laminated photosensitive layer and are negatively charged. Therefore, an intermediate layer needs to contain an acceptor material, but acceptors exhibiting excellent electron transfer characteristics. There is a problem that there are few materials and there is a deterioration in characteristics due to oxygen during handling.
JP-A-5-181299 JP 2002-6526 A JP 2002-82465 A JP 2000-284514 A JP 2001-194413 A Japanese Patent Laid-Open No. 3-45762 Japanese Patent Laid-Open No. 7-281463 JP 2006-259141 A

  An object of the present invention is to provide a photoconductor capable of forming an image with few defects even after long-term use in view of the problems of the above-described conventional technology. Another object of the present invention is to provide an image forming method using the photoreceptor, an image forming apparatus having the photoreceptor, and a process cartridge.

  The invention according to claim 1 is a photoreceptor in which at least an intermediate layer, a charge generation layer, and a charge transport layer are sequentially laminated on a conductive support, the intermediate layer comprising an inorganic semiconductor The charge generation layer contains a charge generation material, and the electron affinity of the inorganic semiconductor is smaller than the ionization potential of the charge generation material. According to the present invention, it is possible to suppress the injection of positive charges from the intermediate layer into the charge generation layer by utilizing the electrical characteristics unique to each other. As a result, it is possible to provide a photoconductor that can form an image with few defects even after long-term use.

  According to a second aspect of the present invention, in the photoreceptor according to the first aspect, a difference between an electron affinity of the inorganic semiconductor and an ionization potential of the charge generation material is larger than 1.0 eV. According to the present invention, injection of positive charges from the intermediate layer to the charge generation layer can be effectively suppressed. As a result, a photoreceptor capable of forming an image with few defects even after long-term use is obtained.

  According to a third aspect of the present invention, in the photoconductor of the first or second aspect, the electron affinity of the inorganic semiconductor is larger than the electron affinity of the charge generation material. According to the present invention, it is possible to easily inject electrons generated in the charge generation layer into the intermediate layer by irradiation with light. As a result, the potential of the exposed portion can be kept low even after long-term use.

  According to a fourth aspect of the present invention, in the photoreceptor according to any one of the first to third aspects, a band gap of the inorganic semiconductor is larger than 2.0 eV. According to the present invention, hole injection between an inorganic semiconductor and a conductive support can be reduced. As a result, a photoreceptor capable of forming an image with few defects even after long-term use is obtained.

  According to a fifth aspect of the present invention, in the photoreceptor according to any one of the first to fourth aspects, the inorganic semiconductor is an oxide semiconductor or a composite oxide semiconductor. According to the present invention, it is possible to suppress the injection of positive charges from the intermediate layer into the charge generation layer by utilizing the electrical characteristics unique to each other. As a result, it is possible to provide a photoconductor capable of forming an image with little deterioration in chargeability and few defects even after long-term use.

  According to a sixth aspect of the present invention, in the photoreceptor according to any one of the first to fifth aspects, the conductive support has a surface roughness Rz of 0.6 μm or more. According to the present invention, it is possible to suppress the occurrence of moire even when the photosensitive member is exposed with writing light having high coherency.

  According to a seventh aspect of the present invention, in the image forming method, at least the step of charging the photosensitive member according to any one of the first to sixth aspects, and forming an electrostatic latent image on the charged photosensitive member. A step of attaching a toner to the formed electrostatic latent image to form a toner image, a step of transferring the formed toner image to a transfer target, and the toner image on the transfer target The step of removing the toner remaining on the transferred photoconductor is repeated. According to the present invention, it is possible to provide an image forming method capable of forming an image with few defects even after long-term use.

  According to an eighth aspect of the present invention, in the image forming apparatus, the photosensitive member according to any one of the first to sixth aspects, a means for charging the photosensitive member, and an electrostatic latent image on the charged photosensitive member. Means for forming an image; means for forming a toner image by attaching toner to the formed electrostatic latent image; means for transferring the formed toner image to a transfer target; and It has at least means for removing toner remaining on the photosensitive member transferred to the transfer member. According to the present invention, it is possible to provide an image forming apparatus capable of forming an image with few defects even when used for a long time.

  According to a ninth aspect of the present invention, in the process cartridge, the photosensitive member according to any one of the first to sixth aspects, a means for charging the photosensitive member, and an electrostatic latent image on the charged photosensitive member. Forming means, means for forming a toner image by attaching toner to the formed electrostatic latent image, means for transferring the formed toner image to a transferred body, and the toner image being transferred to the transferred body. And at least one means selected from the group consisting of means for removing toner remaining on the photosensitive member, and is detachable from the main body of the image forming apparatus. According to the present invention, it is possible to provide a process cartridge capable of forming an image with few defects even after long-term use.

  According to the present invention, it is possible to provide a photoconductor capable of forming an image with few defects even after long-term use. Further, according to the present invention, it is possible to provide an image forming method using the photoconductor, an image forming apparatus having the photoconductor, and a process cartridge.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

  The photoreceptor of the present invention is a photoreceptor in which at least an intermediate layer, a charge generation layer, and a charge transport layer are sequentially laminated on a conductive support, and the intermediate layer is made of an inorganic semiconductor, The electron affinity (energy difference from the bottom of the conduction band to the vacuum level) of the inorganic semiconductor containing the charge generation material is smaller than the ionization potential of the charge generation material. As a result, injection of unnecessary charges from the conductive support to the charge generation layer and the charge transport layer is suppressed, and charge trapping into the intermediate layer does not occur even when used, and charging of the photoreceptor over a long period of time. Therefore, the output image defect can be extremely reduced. Further, since the constituent material of the photoreceptor is very strong against charge hazard, the chargeability can be maintained over a long period of time. As a result, it is possible to suppress the occurrence of defects in the output image, such as a decrease in image density and the occurrence of background stains, even when the photoreceptor is used repeatedly.

  In general, the charging process in the electrophotographic image forming process is to charge the surface of the photoconductor to a constant potential, and the uniformity is related to image density unevenness, and the charging ability is related to high speed. This is an important technology for speeding up. The characteristics necessary for uniformly charging the surface of the photoreceptor include that there is no unnecessary charge injection from the conductive support and that there are few charge traps in the photoreceptor. When a photoconductor that does not have these characteristics is charged, charge of the opposite polarity is injected from the conductive support, canceling the charge applied to the surface, or applying the accumulated charge in the photoconductor to the surface. The desired chargeability cannot be obtained by canceling the generated charges.

  In addition, as a recent development trend of photoconductors, the service life has been extended with a focus on environmental friendliness and ease of maintenance, so there is no unnecessary charge injection from the conductive support, Therefore, there is a demand for maintaining a small number of charge traps over a long period of time. In other words, even if the characteristics related to the chargeability are excellent in the initial stage, the organic material constituting the photoconductor deteriorates due to use, and an unnecessary charge injection site is generated, or a new charge is generated in the layer. It drops when a trap occurs. For this reason, the electrical durability of the material constituting the photoreceptor is required.

  The photoreceptor of the present invention applies an inorganic semiconductor having durability against passing charges to the intermediate layer, and uses an inorganic semiconductor that is less likely to electrochemically inject unnecessary charges into the charge generation layer. It is possible to obtain an excellent photoconductor that is less likely to cause a decrease in chargeability over a long period of time.

  In the present invention, the electron affinity of the inorganic semiconductor constituting the intermediate layer needs to be smaller than the ionization potential of the charge generation material contained in the charge generation layer. The reason for this will be described below. A photoreceptor having a laminated photosensitive layer is usually used with its surface negatively charged. However, if the electron affinity of the inorganic semiconductor is larger than the ionization potential of the charge generating material, the inorganic semiconductor may cause the HOMO ( It is thought that the electrons of the highest occupied molecular orbital are extracted. In addition, since electrons are injected and holes are transported from the charge transport layer so as to compensate for the holes generated thereby, the negative charge imparted to the surface of the photoreceptor is canceled by the transported holes. Conceivable. In order to prevent such a phenomenon from occurring, the electron affinity of the inorganic semiconductor needs to be smaller than the ionization potential of the charge generation material.

  In addition, when the electron affinity of the inorganic semiconductor is larger than the electron affinity of the charge generation material (energy difference from the LUMO (lowest empty molecular orbital) to the vacuum level), the electrons excited to the LUMO of the charge generation material by light irradiation are It is easy to move to the conductive support through the intermediate layer. For this reason, in order to keep the potential of the exposed portion of the photoreceptor low, it is preferable that the electron affinity of the inorganic semiconductor is larger than the electron affinity of the charge generation material.

  Furthermore, in order to suppress injection of holes from the conductive support to the intermediate layer, it is preferable to increase the band gap of the inorganic semiconductor. Thereby, it becomes possible to reduce the inflow of electrons from the valence band of the intermediate layer to the Fermi level of the conductive support.

  In the present invention, it is preferable to use an inorganic semiconductor satisfying all such electrochemical characteristics as the intermediate layer.

  In general, organic semiconductors are widely handled in the field of electrophotographic photoreceptors due to the variety of types, easy control of absorption spectra, and ease of device formation, but on the other hand, the binding energy is small, light, Due to heat, electrical hazards, etc., characteristic changes easily occur due to structural changes. On the other hand, inorganic semiconductors have few materials that can be used, making device design difficult, and tending to increase the cost and time required for film formation. In the field of electrophotographic photoreceptors, amorphous silicon is the only commercial product. Only. However, inorganic semiconductors, including amorphous silicon, have extremely strong covalent bonding, and structural changes do not occur due to light, heat, electrical hazards, etc., so they maintain stable characteristics over a long period of time. be able to. In the present invention, by selecting the electrochemical characteristics of the inorganic semiconductor, it is possible to obtain a photoreceptor that hardly injects holes from the conductive support to the charge generation layer and the charge transport layer.

  Next, a method for measuring the electron affinity of the inorganic semiconductor will be described. The electron affinity of the inorganic semiconductor can be obtained by subtracting the band gap value from the energy difference from the valence band to the vacuum level obtained by the Kelvin method or photoelectron spectroscopy (X-rays / ultraviolet rays). In the present invention, the work function is measured using the Kelvin method. Here, the measurement principle of the Kelvin method will be briefly described. The Kelvin method is a measurement method using a contact potential difference between a substance having a known work function and a desired substance. That is, when two substances having different work functions are brought into contact with each other, a current flows so that the Fermi levels are the same, and a potential difference is generated in an equilibrium state. This potential difference corresponds to the difference between the work functions of the two substances. Accordingly, two plate electrodes of the measurement sample A with unknown work function and the standard sample B with known work function (platinum in the present invention) are prepared, and are brought close to each other or separated from each other. Since an alternating current flows with the vibration probe method and the vibration capacity method (Kelvin method), the work function can be measured by measuring the voltage at that time. As a measuring device, a UHV Kelvin probe (manufactured by Tech Science) or the like can be used.

Next, a method for measuring the band gap will be described. In the present invention, Tauc plot, which is known as one of photochemical measurement techniques, is used for band gap measurement, but is not particularly limited as long as a physically equivalent characteristic value can be obtained. Here, the measurement principle of the band gap energy E ₀ using the Tauc plot will be described. In general, in a region of relatively large absorption near the optical absorption edge on the long wavelength side of a semiconductor, an absorption coefficient α, light energy hν (where h is a Planck constant, and ν is a wave number), and bandcap energy. Between E ₀ , the formula αhν = B (hν−E ₀ ) ² (where B is a constant)
Is considered to hold. Therefore, the absorption spectrum is measured, hν is plotted against the (αhν) ^1/2 (so-called Tauc plot), and the value of hν at α = 0 obtained by extrapolating the straight section becomes the band gap energy E ₀ .

  The electron affinity can be obtained from the work function and band gap energy of the valence band obtained by these methods.

  In the present invention, the electron affinity of the inorganic semiconductor needs to be smaller than the ionization potential of the charge generating material, but the energy difference is preferably larger than 1.0 eV, more preferably 1.2 eV or more. Although the hole blocking property is exhibited even when the difference between the electron affinity of the inorganic semiconductor and the ionization potential of the charge generation material is 1.0 eV or less, the function may not be sufficiently exhibited depending on the inorganic semiconductor used. Moreover, in order to express the hole blocking property, the upper limit of the energy difference is not particularly specified, but when the energy difference is too large, the electron affinity of the inorganic semiconductor is higher than the electron affinity of the charge generation material as described later. May be smaller. As a result, electrons formed in the charge generation material in the writing process in the electrophotographic process are difficult to inject into the inorganic semiconductor, causing unnecessary electrons to remain at the interface between the charge generation layer and the intermediate layer.

  Next, the electron affinity and ionization potential of the organic material will be briefly described. The electron affinity of the organic material means an energy difference from the LUMO to the vacuum level, and the ionization potential of the organic material means an energy difference from the HOMO to the vacuum level.

  Although the ionization potential can be obtained using the Kelvin method, it can be obtained relatively easily using the photoelectron spectroscopy measurement method. Here, the basic principle of the photoelectron spectroscopy measurement method will be described. Since the number of photoelectrons emitted when the surface of the sample is irradiated with ultraviolet rays changes depending on the energy of the ultraviolet rays, tracing the change in the amount of photoelectrons emitted when the light energy is continuously changed Thus, energy for starting the emission of photoelectrons is obtained. In the present invention, the ionization potential is obtained from photoelectron spectroscopy. Specifically, a film (in the present invention, a resin film having the same composition as the charge generation layer) is formed on an Al plate having a smooth surface, and an atmospheric photoelectron spectrometer AC-2 (manufactured by Riken Keiki Co., Ltd.) is used. The ionization potential of the film can be measured.

Further, the electron affinity is obtained by subtracting the transition energy between HOMO / LUMO from the ionization potential. In the present invention, the transition energy E [eV] between HOMO / LUMO is expressed by the equation E = 1239.8 / λ from the absorption edge wavelength λ [nm].
Is calculated using In general, the definition of the absorption edge is not unified, but in the present invention, the wavelength converted value of the band gap energy corresponding to the transition energy between HOMO / LUMO obtained by applying the Tauc plot to an organic material is used. Used as absorption edge wavelength.

  Note that the method for measuring the ionization potential and the electron affinity is not limited to the above method as long as the method can obtain electrochemically equivalent characteristic values.

  In the present invention, the band gap of the inorganic semiconductor is also related to the hole blocking property from the conductive support. By using an inorganic semiconductor with a large band gap for the intermediate layer, the energy difference from the valence band to the vacuum level is increased, and hole injection from the Fermi level of the metal used for the conductive support can be suppressed. . The band gap of the inorganic semiconductor is preferably larger than 2.0 eV, more preferably 2.5 eV or more. When the band gap is 2.0 eV or less, the valence band of the inorganic semiconductor exceeds the Fermi level of the metal (aluminum, nickel, chromium, nichrome, etc.) used for the conductive support, or is used for the conductive support. In some cases, the energy difference between the Fermi level of the obtained metal and the valence band of the inorganic semiconductor becomes small, so that the hole blocking property cannot be sufficiently compensated. As a result, holes are easily injected from the conductive support to the intermediate layer.

  The band gap may be measured using the above-described method, or when a characteristic value having the same meaning electrochemically is obtained, it is not particularly limited, and various measurement methods may be used.

  In the present invention, the intermediate layer preferably has a hole blocking property from the conductive support to the charge generation layer and the charge transport layer, and preferably has an electron transport property from the charge generation layer to the conductive support. The hole blocking property can be achieved by the electron affinity and band gap of the inorganic semiconductor. On the other hand, with respect to electron transport properties, a so-called n-type semiconductor in which an electron carrier is present in an inorganic semiconductor is preferable. The carrier concentration or the like is not particularly limited, but if the carrier concentration becomes too high, the charge generated in the charge generation layer near the intermediate layer may be erased.

  Although the inorganic semiconductor is not particularly limited, examples of the n-type semiconductor include oxide semiconductors such as titanium oxide, tin oxide, zinc oxide, indium oxide, niobium oxide, tungsten oxide, and vanadium oxide, strontium titanate, calcium titanate, and titanium. Binary complex oxide semiconductors such as barium oxide and potassium niobate, ternary complex oxide semiconductors such as In-Ga-Zn-O (IGZO), cadmium and bismuth sulfides, cadmium selenides, Examples include tellurides, gallium phosphides, arsenides, and the like, and two or more of them may be used in combination. Among these, an oxide semiconductor or a composite oxide semiconductor is preferable because the chargeability is hardly lowered even after long-term use. Moreover, a donor component may be contained in the inorganic semiconductor as an electron carrier. Examples of the donor component include group III elements such as Al, B, Ga, and In, and group IV elements such as Si, Ge, Ti, Zr, and Hf.

  The method for depositing the inorganic semiconductor on the conductive support is not particularly limited. Inorganic semiconductor film forming methods are roughly classified into vapor phase growth methods, liquid phase growth methods, and solid phase growth methods. Vapor deposition is further classified into physical vapor deposition (PVD) and chemical vapor deposition (CVD). As physical vapor deposition, vacuum deposition and electron beam deposition are used. , Laser ablation MBE method, MOMBE method, reactive vapor deposition method, ion plating method, cluster ion beam method, glow discharge sputtering method, ion beam sputtering method, reactive sputtering method and the like. Examples of the liquid phase growth method include a thermal CVD method, an MOCVD method, an RF plasma CVD method, an ECR plasma CVD method, a photo CVD method, and a laser CVD method. Examples of the liquid phase method include an LPE method, an electroplating method, an electroless plating method, and a coating method. Examples of the solid phase method include an SPE method, a recrystallization method, a graphoepitaxy method, an LB method, and a sol-gel method.

  Although the film thickness of an intermediate | middle layer is not specifically limited, It is preferable that it is 0.1-10 micrometers, and 0.5-7 micrometers is further more preferable. If the film thickness is less than 0.1 μm, the conductive support may not be uniformly coated or a partial charge leak point may be formed. On the other hand, if the film thickness is greater than 10 μm, the intermediate layer may be cracked or contact with the conductive support may be insufficient due to the difference in the coefficient of thermal expansion with the conductive support.

  The intermediate layer may be polycrystalline, single crystal, or amorphous. In general, it is difficult for a film having a grain boundary to control charge transport at the grain boundary. Therefore, the intermediate layer preferably has few grain boundaries. Examples of such an intermediate layer include amorphous, single crystal, and polycrystalline with few grain boundaries.

  Next, other layers of the photoreceptor of the present invention will be described.

  The charge generation layer is a layer mainly composed of a charge generation material having a charge generation function, and a binder resin can be used in combination as necessary. As the charge generation material, inorganic materials and organic materials can be used.

  Inorganic materials include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compounds, amorphous silicon, and the like. As amorphous silicon, it is preferable to use dangling bonds terminated with hydrogen atoms or halogen atoms, or doped with boron atoms or phosphorus atoms.

  On the other hand, the organic materials include metal phthalocyanine, metal-free phthalocyanine and other phthalocyanine pigments, azulenium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triarylamine skeleton, and diphenylamine skeletons Azo pigments, azo pigments having a dibenzothiophene skeleton, azo pigments having a fluorenone skeleton, azo pigments having an oxadiazole skeleton, azo pigments having a bis-stilbene skeleton, azo pigments having a distyryl oxadiazole skeleton, distyrylcarbazole skeleton Azo pigments, perylene pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomes Emissions based pigments, indigoid pigments, include bisbenzimidazole pigments may be used alone or in combination.

  Binder resins used as necessary for the charge generation layer include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly (N-vinylcarbazole). , Polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, etc. You may use together. The addition amount of the binder resin is usually 0 to 500 parts by weight and preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generating material. Note that the binder resin may be added before or after dispersion.

  Methods for forming the charge generation layer are roughly classified into vacuum thin film fabrication methods and casting methods. Examples of vacuum thin film fabrication methods include vacuum deposition, glow discharge decomposition, ion plating, sputtering, reactive sputtering, CVD, etc., and charge generation layers using inorganic and organic materials. Can be formed. As the casting method, an inorganic material or an organic material, together with a binder resin, if necessary, tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclopentanone, anisole, xylene, Examples thereof include a method in which a dispersion liquid dispersed by a ball mill, an attritor, a sand mill, a bead mill or the like is appropriately diluted and applied using a solvent such as methyl ethyl ketone, acetone, ethyl acetate, or butyl acetate. At this time, a leveling agent such as dimethyl silicone oil or methylphenyl silicone oil can be added to the dispersion as necessary. Examples of the coating method include a dip coating method, a spray coating method, a bead coating method, and a ring coating method.

  The thickness of the charge generation layer is usually 0.01 to 5 μm, preferably 0.05 to 2 μm.

  The charge transport layer is a layer mainly composed of a charge transport material having a charge transport function and a binder resin.

  Charge transport materials are roughly classified into hole transport materials and electron transport materials. Examples of the electron transport material include chloroanil, bromoanil, 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-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-trinitro Examples include dibenzothiophene-5,5-dioxide, diphenoquinone derivatives, and the like, and two or more of them may be used in combination. Examples of hole transport materials include poly (N-vinylcarbazole) and derivatives thereof, poly (γ-carbazolylethyl glutamate) and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, and oxazole. Derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives Pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, enamine derivatives, etc. 2 or more types may be used in combination.

  Binder resins include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, poly Vinylidene chloride, polyarylate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly (N-vinylcarbazole), acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, Examples thereof include thermoplastic or thermosetting resins such as phenol resins and alkyd resins. In addition, as a binder resin, a polymer charge transport material having a charge transport function, for example, an arylamine skeleton, a benzidine skeleton, a hydrazone skeleton, a carbazole skeleton, a stilbene skeleton, a pyrazoline skeleton, a polycarbonate, a polyester, a polyurethane, a polyether, a poly It is also possible to use a polymer material such as siloxane or an acrylic resin, a polymer material having a polysilane skeleton, or the like.

  The amount of the charge transport material added is usually 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. However, when a polymer charge transport material is used, it may be used alone or in combination with a binder resin.

  The charge transport layer can be formed by applying a coating solution. Examples of the solvent for the coating solution include tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone, and the like. Moreover, a plasticizer and a leveling agent can also be added to a coating liquid as needed. Examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, and the like, and the addition amount is usually 0 to 30% by weight with respect to 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 the side chain. 1% by weight.

  The thickness of the charge transport layer is preferably 30 μm or less, more preferably 25 μm or less, from the viewpoint of resolution and responsiveness. The lower limit of the film thickness varies depending on the system to be used (particularly charging potential), but is preferably 5 μm or more.

  Further, in the present invention, an antioxidant is added to each layer such as an intermediate layer, a charge generation layer, and a charge transport layer in order to improve environmental resistance, and particularly to suppress a decrease in sensitivity and an increase in residual potential. can do.

  Examples of the antioxidant that can be used in the present invention include the following compounds.

<Phenolic compound>
2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, β- (3,5-di-t-butyl-4-hydroxy Phenyl) stearyl propionate, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-thiobis (3 -Methyl-6-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) ) Butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3- (3 ′, 5′-di) − - butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis (4'-hydroxy-3'-t-butylphenyl) butyric acid] click recall esters, tocopherols and the like.

<Paraphenylenediamines>
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-s-butyl-p-phenylenediamine, N-phenyl-N-s-butyl-p-phenylenediamine, N, N'- Diisopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.

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

<Organic sulfur compounds>
Dilauryl 3,3′-thiodipropionate, distearyl 3,3′-thiodipropionate, ditetradecyl 3,3′-thiodipropionate, and the like.

<Organic phosphorus compounds>
Triphenylphosphine, tris (nonylphenyl) phosphine, tris (dinonylphenyl) phosphine, tricresylphosphine, tris (2,4-dibutylphenoxy) phosphine and the like.

  These compounds are known as antioxidants such as rubbers, plastics, fats and oils, and commercially available products can be easily obtained.

  In this invention, the addition amount of antioxidant is 0.01 to 10 weight% with respect to the total weight of the layer to add.

In the present invention, the conductive support may be a conductive material having a volume resistance of 10 ¹⁰ Ω · cm or less, such as a metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, or platinum, or an oxide. A metal oxide such as tin or indium oxide coated with a film or cylindrical plastic or paper by vapor deposition or sputtering can be used. In addition, as the conductive support, a tube made of aluminum, aluminum alloy, nickel, stainless steel or the like and a tube subjected to surface treatment such as cutting, super-finishing, polishing, etc. after extruding them and making them into tubes by a method such as drawing Etc. can be used. Furthermore, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used as the conductive support.

  In addition to these, those obtained by coating a conductive layer in which conductive powder is dispersed in a binder resin on the conductive support described above can also be used as the conductive support. Examples of the conductive powder include carbon powder such as carbon black and acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, metal oxide powder such as conductive tin oxide and ITO. It is done. The binder resin includes polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate. , Polyvinylidene chloride, polyarylate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly (N-vinylcarbazole), acrylic resin, silicone resin, epoxy resin, melamine resin, urethane Examples thereof include thermoplastic resins such as resins, phenol resins, and alkyd resins, thermosetting resins, and photocurable resins. The conductive layer can be formed by dispersing conductive powder and a binder resin in a solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene, and applying.

  Furthermore, a heat-shrinkable tube containing the above conductive powder in a resin such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, polytetrafluoroethylene-based fluororesin on a cylindrical substrate. What formed the conductive layer using can also be used as a conductive support.

  In general, in the electrophotographic process, when forming a latent image, a highly coherent laser may be used. At this time, when the photoconductor of the present invention is produced using a conductive support having high reflectivity, interference may occur between the writing light and the reflected light from the conductive support, resulting in image defects. is there. For this reason, when the reflectivity of the conductive support is high, it is preferable to make the surface of the conductive support uneven to reduce the reflectivity. Further, protrusions and the like that are potentially present on the raw tube may cause image defects when the photosensitive layer is laminated. For this reason, a smooth surface without projections can be formed by roughening the raw tube to an appropriate surface roughness. In the present invention, the arithmetic ten-point average surface roughness Rz measured by the method shown in JIS B0601-1982 is used as the surface roughness. Specifically, the surface roughness Rz is measured with respect to an evaluation length of 2.5 mm and a reference length of 0.5 mm using Surfcom 1400D (manufactured by Tokyo Seimitsu Co., Ltd.). When measuring the surface roughness Rz of the drum-shaped conductive support, measure 12 points in total, measuring 80 points from the both ends of the drum in the axial direction, 3 points in the center of the drum, and 90 ways in the circumferential direction. . In the present invention, the surface roughness Rz of the conductive support is preferably 0.6 μm or more. If the surface roughness Rz is smaller than 0.6 μm, moire due to writing light may occur. Further, the surface roughness Rz of the conductive support is preferably 3.0 μm or less. If the surface roughness Rz is larger than 3.0 μm, it may be difficult to form the intermediate layer uniformly.

  Examples of the method for roughening the conductive indicator include honing and centerless polishing. Honing is inexpensive and the surface roughness can be easily adjusted. There are dry and wet processing methods for honing, but any of them may be used. Wet (liquid) honing is a method in which a powdery abrasive (abrasive grain) is suspended in a liquid such as water and then sprayed onto the surface of the conductive support at high speed to roughen the surface. Can be controlled by spraying pressure, speed, amount of abrasive, type, shape, size, hardness, specific gravity, suspension concentration, and the like. The dry honing process is a method in which an abrasive is sprayed onto the surface of the conductive support at high speed with air to roughen the surface, and the surface roughness can be controlled similarly to the wet honing process. Examples of the abrasive used for these honing processes include particles of silicon carbide, alumina, zirconia, stainless steel, iron, glass beads, plastic shots, and the like.

  However, in the case of dry honing or liquid honing using amorphous alumina abrasive grains, the abrasive grains may pierce the surface of the conductive support, and when the photosensitive member is produced, It may appear as white spots on a black image in a transfer development system. Further, in liquid honing using glass beads, the glass beads may break and pierce the surface of the conductive support, making it difficult to control the surface roughness. For this reason, it is a general practice to prepare a photoconductor after roughening the conductive support by liquid honing using spherical alumina abrasive grains, stainless steel abrasive grains or the like as an abrasive. Further, in the roughening treatment of the conductive support, from the viewpoint of the processing time, the amount of abrasive grains used, the amount of energy used, the ease of removing the abrasive grains remaining on the roughened conductive substrate, etc. It is desirable to make the processing conditions mild to reduce the surface roughness.

  Next, an image forming method, an image forming apparatus, and a process cartridge according to the present invention will be described.

  In the image forming method of the present invention, for example, at least after the photosensitive member of the present invention is charged, image exposed and developed, the toner image is transferred to a transfer target (transfer paper), fixed and transferred. The process of cleaning the surface is repeated. Note that an image forming apparatus that directly develops an electrostatic latent image onto a transfer target does not necessarily have these processes.

  FIG. 1 shows an example of an image forming apparatus of the present invention. In the image forming apparatus shown in FIG. 1, a charging charger 3 is used as a means for charging the photosensitive member 1 on the average. Examples of the charging charger 3 include a corotron device, a scorotron device, a solid discharge element, a needle electrode device, a roller charging device, and a conductive brush device, and a known method can be used. At this time, the eraser 4 is used as means for erasing unnecessary charges on the photoreceptor 1 as necessary.

  Next, the image exposure unit 5 is used as means for forming an electrostatic latent image on the uniformly charged photoreceptor 1. As a light source of the image exposure unit 5, a general light emitting material 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 electroluminescence (EL) can be used. . 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.

  Next, the developing unit 6 is used as means for visualizing the electrostatic latent image formed on the photoreceptor 1. Examples of the development method include a one-component development method using a dry toner, a two-component development method, and a wet development method using a wet toner. When the photosensitive member 1 is positively (or negatively) charged and image exposure is performed, a positive (or negative) electrostatic latent image is formed on the surface of the photosensitive member 1. If this electrostatic latent image is developed with negative (or positive) polarity toner (detection fine particles), a positive image is obtained. Further, a negative image can be obtained by developing the electrostatic latent image with positive (or negative) toner.

  Next, a transfer charger 10 is used as a means for transferring the toner image visualized on the photosensitive member 1 onto the transfer target 9 conveyed by the registration roller 8. In addition, a pre-transfer charger 7 may be used for good transfer. Examples of transfer means other than the transfer charger 10 include an electrostatic transfer method using a bias roller, a mechanical transfer method such as an adhesive transfer method and a pressure transfer method, and a magnetic transfer method. For the electrostatic transfer system, the above charging means can be used.

  Next, a separation charger 11 and a separation claw 12 are used as means for separating the transfer target 9 from the photoreceptor 1. Other separation means include electrostatic adsorption induction separation, side end belt separation, tip grip conveyance, curvature separation, and the like. As the separation charger 11, the above charging means can be used.

  Next, a fur brush 14 and a cleaning blade 15 are used as means for cleaning the toner remaining on the photoreceptor 1 after the transfer. Further, a pre-cleaning charger 13 may be used for efficient cleaning. Other cleaning means include a web method, a magnet brush method, and the like, and a plurality of methods may be used in combination.

  Next, the neutralizing lamp 2 is used as a means for erasing the electrostatic latent image on the photoreceptor 1 as necessary. As the static elimination lamp 2, the light source of the image exposure unit 5 can be used. Examples of the charge removal means other than the charge removal lamp 2 include a charge removal charger, and the above charging means can be used.

  In addition, known means can be used for processes such as document reading, paper feeding, fixing, and paper ejection that are not close to the photoreceptor 1.

  The image forming apparatus of the present invention uses the photosensitive member of the present invention as an image forming means, but the image forming means may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, but in the form of a process cartridge. It may be incorporated in these devices and made detachable. The process cartridge is an apparatus (part) that has a built-in photoconductor, and further includes at least one of a charging unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit, and is detachable from the image forming apparatus main body. .

  FIG. 2 shows an example of the process cartridge of the present invention. In the process cartridge shown in FIG. 2, an electrostatic latent image corresponding to the exposure image is formed on the surface of the photoconductor 101 by charging by the charging device 102 and exposure 103 by the exposure unit while rotating the photoconductor 101. The electrostatic latent image is developed by the developing device 104, and the obtained toner image is transferred to the transfer medium 105 by the transfer device 106 and printed out. Next, the surface of the photoreceptor 101 after the transfer is cleaned by the cleaning device 107 and the above operation is repeated again.

  EXAMPLES Next, although an Example demonstrates this invention in detail, this invention is not limited to a following example. In addition, a part means a weight part.

<Example 1>
An aluminum cylinder having a surface roughness Rz of 0.9 μm and a diameter of 30 mm was prepared, and an intermediate layer was formed using an ion plating apparatus improved so that ZnO could be formed while rotating the cylinder. Note that undoped ZnO easily changes its conductivity due to light. Therefore, ZnO containing 1 wt% Ga ₂ O ₃ is used as a target, and Ga-doped ZnO (electron affinity) with a film thickness of 0.5 μm is used. An intermediate layer composed of 4.4 eV and a band gap of 3.3 eV was formed. When forming the intermediate layer, the temperature of the cylinder was 30 ° C., and the flow rates of oxygen gas and argon gas were 15 sccm and 100 sccm, respectively.

  Next, a charge generation layer coating solution and a charge transport layer coating solution are sequentially applied and dried to form a charge generation layer having a thickness of 0.2 μm and a charge transport layer having a thickness of 18 μm. A photoreceptor was obtained. The composition of the charge generation layer coating solution is structural formula

で表される電荷発生材料（電子親和力４．１ｅＶ、イオン化ポテンシャル５．９ｅＶ）２．５部、ポリビニルブチラールＸＹＨＬ（ＵＣＣ社製）０．５部、シクロヘキサノン２００部及びメチルエチルケトン８０部であり、電荷輸送層用塗工液の組成は、ビスフェノールＺポリカーボネートのパンライトＴＳ−２０５０（帝人化成社製）１０部、構造式

Charge generation material (electron affinity 4.1 eV, ionization potential 5.9 eV) 2.5 parts, polyvinyl butyral XYHL (UCC) 0.5 parts, cyclohexanone 200 parts and methyl ethyl ketone 80 parts, The composition of the coating liquid for layer is 10 parts of bisphenol Z polycarbonate Panlite TS-2050 (manufactured by Teijin Chemicals Ltd.), structural formula

で表される電荷輸送材料７部、テトラヒドロフラン１００部及び１重量％のシリコーンオイルのテトラヒドロフラン溶液ＫＦ５０−１００ＣＳ（信越化学工業社製）１部である。

7 parts of a charge transport material represented by the following formula: 100 parts of tetrahydrofuran and 1 part of a tetrahydrofuran solution KF50-100CS (manufactured by Shin-Etsu Chemical Co., Ltd.) of 1% by weight of silicone oil.

<Example 2>
A photoconductor was obtained in the same manner as in Example 1 except that an intermediate layer made of an oxide semiconductor IGZO (electron affinity 4.2 eV, band gap 3.2 eV) having a thickness of 0.7 μm was formed. The intermediate layer was formed using an RF sputtering apparatus, and a polycrystalline sintered body InGaO ₃ (ZnO) ₄ was used as a target. At this time, the polycrystalline sintered body was obtained by wet-mixing In ₂ O ₃ , Ga ₂ O ₃ and ZnO using ethanol and then sintering. When forming the intermediate layer, the back pressure is 5 × 10 ⁻⁶ Pa, the film forming pressure is 8 × 10 ⁻³ Pa, the RF power is 16.7 W / cm ² , and the inert gas is argon gas. The flow rates of argon gas and oxygen gas were 38 ccm and 2 ccm, respectively. The distance between the target and the cylinder was 30 mm. Note that the formed intermediate layer is an amorphous film.

<Example 3>
A photoconductor was obtained in the same manner as in Example 2 except that when the intermediate layer was formed, the flow rates of argon gas and oxygen gas were 38.8 ccm and 1.2 ccm, respectively.

<Example 4>
A photoconductor was obtained in the same manner as in Example 1 except that the surface roughness Rz of the aluminum cylinder was changed to 0.3 μm.

<Example 5>
A photoconductor was obtained in the same manner as in Example 2 except that the surface roughness Rz of the aluminum cylinder was changed to 0.3 μm.

<Example 6>
A photoconductor was obtained in the same manner as in Example 3 except that the surface roughness Rz of the aluminum cylinder was changed to 0.3 μm.

<Comparative Example 1>
A photoconductor was obtained in the same manner as in Example 1 except that no intermediate layer was formed.

<Comparative example 2>
A photoconductor in the same manner as in Example 1 except that the intermediate layer was formed by dipping using the intermediate layer coating solution, dried by touch and then heated and dried at 135 ° C. for 20 minutes. Got. The composition of the intermediate layer coating solution was 6 parts of alkyd resin Beccosol 1307-60-EL (Dainippon Ink Chemical Co., Ltd.), melamine resin Super Becamine G-821-60 (Dainippon Ink Chemical Co., Ltd.). ) 4 parts, titanium oxide 40 parts and methyl ethyl ketone 50 parts.

<Evaluation method and evaluation results>
Using the photoreceptors obtained in Examples 1 to 6 and Comparative Examples 1 and 2, a running test using an actual machine was performed. As a real machine, a modified machine of IPSiO Color CX9000 (manufactured by Ricoh) was used. Further, as the toner, Imagio toner type 27 (manufactured by Ricoh) was used, and as the paper, MyPaper (A4 size) (manufactured by NBS Ricoh) was used. The surface potential of the photosensitive member at the start was set to −650 V, and the surface potentials (after charging and after exposure) at the initial stage of 20,000 sheets and 50,000 sheets were measured. The measurement results are shown in Table 1.

実施例２、３、５及び６の感光体は、帯電後の表面電位から、十分な帯電性が得られると共に、使用による帯電性の変動が小さいことがわかり、露光後の表面電位から、書き込み光による表面電位の低下が十分であることがわかる。

It can be seen from the surface potentials after charging that the photoconductors of Examples 2, 3, 5 and 6 have sufficient chargeability and small fluctuations in chargeability due to use. It can be seen that the surface potential is sufficiently lowered by light.

  In addition, the photoconductors of Examples 1 and 4 showed variations in the surface potential after charging and the surface potential after exposure due to use as compared with the photoconductors of Examples 2, 3, 5 and 6. Compared with the photoreceptor of Example 2, it can be seen that the decrease in surface potential due to writing light is large. The cause of this is unknown, but it is thought that one reason is that the Ga-doped ZnO is polycrystalline.

  On the other hand, the photoreceptor of Comparative Example 1 had insufficient surface potential after charging even in the initial stage, and the running test could not be performed.

  In addition, the photoreceptor of Comparative Example 2 has a commonly used fine particle dispersion type intermediate layer. However, sufficient chargeability is obtained in the initial stage from the surface potential after charging, but fluctuations in chargeability due to use are observed. From the surface potential after exposure, it can be seen that the decrease in the surface potential due to writing light is small compared to the photoreceptors of Examples 1 to 6.

  Next, after 50,000 sheets of running were completed, image output was evaluated by performing continuous white background output and halftone output for five sheets continuously and confirming background contamination and density unevenness. The photoconductors of Examples 1 to 3 have good output images, whereas the photoconductors of Examples 4 to 6 have a slight moire. Although this cause is not clear, it can be estimated from the comparison with Examples 1 to 3 that the influence of the writing light reflected from the conductive support is large. On the other hand, in the photoconductor of Comparative Example 2, background smear occurred on the entire white background output, and density unevenness occurred on the second and subsequent sheets in the halftone output. The background stain is considered to be caused by a partial decrease in charging property due to a decrease in hole blocking property of the intermediate layer. Further, it is considered that the density unevenness is caused by the influence of the previous output image (so-called afterimage).

  From the above, it has been found that the photoconductor of this example has a charging property due to excellent hole blocking property and has few defects relating to image quality even when used for a long time.

1 is a schematic diagram illustrating an example of an image forming apparatus of the present invention. It is the schematic which shows an example of the process cartridge of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charger charger 4 Eraser 5 Image exposure part 6 Development unit 7 Charger before transfer 8 Registration roller 9 Transfer object 10 Transfer charger 11 Separation charger 12 Separation claw 13 Charger before cleaning 14 Fur brush 15 Cleaning blade 101 Photosensitive Body 102 Charging device 103 Exposure 104 Developing device 105 Transfer object 106 Transfer device 107 Cleaning device

Claims (9)

A photosensitive member in which at least an intermediate layer, a charge generation layer, and a charge transport layer are sequentially laminated on a conductive support,
The intermediate layer is made of an inorganic semiconductor,
The charge generation layer contains a charge generation material,
A photoconductor, wherein an electron affinity of the inorganic semiconductor is smaller than an ionization potential of the charge generation material.   The photoreceptor according to claim 1, wherein a difference between an electron affinity of the inorganic semiconductor and an ionization potential of the charge generation material is larger than 1.0 eV.   The photoconductor according to claim 1, wherein an electron affinity of the inorganic semiconductor is larger than an electron affinity of the charge generation material.   The photoconductor according to claim 1, wherein a band gap of the inorganic semiconductor is larger than 2.0 eV.   The photoconductor according to claim 1, wherein the inorganic semiconductor is an oxide semiconductor or a complex oxide semiconductor.   The photoreceptor according to claim 1, wherein the conductive support has a surface roughness Rz of 0.6 μm or more.   At least a step of charging the photoconductor according to any one of claims 1 to 6, a step of forming an electrostatic latent image on the charged photoconductor, and a toner on the formed electrostatic latent image A step of forming a toner image by attaching the toner image, a step of transferring the formed toner image to the transfer member, and a step of removing the toner remaining on the photosensitive member having the toner image transferred to the transfer member. An image forming method characterized by repeating.   7. The photosensitive member according to claim 1, means for charging the photosensitive member, means for forming an electrostatic latent image on the charged photosensitive member, and the formed electrostatic latent image. A means for forming a toner image by attaching toner to the image; a means for transferring the formed toner image to the transfer member; and removing the toner remaining on the photosensitive member having the toner image transferred to the transfer member An image forming apparatus comprising:   7. The photosensitive member according to claim 1, means for charging the photosensitive member, means for forming an electrostatic latent image on the charged photosensitive member, and the formed electrostatic latent image. A means for forming a toner image by attaching toner; a means for transferring the formed toner image to a transfer member; and a means for removing toner remaining on the photosensitive member having the toner image transferred to the transfer member. A process cartridge which is detachable from the main body of the image forming apparatus and has at least one means selected from the group.

Images