JP2007225770A - Image forming apparatus, image forming method and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus and an image forming method by which image density unevenness caused in a low temperature and low humidity environment is suppressed and the original durability of an electrophotographic photoreceptor can be enjoyed, and a process cartridge. <P>SOLUTION: The image forming apparatus includes an electrophotographic photoreceptor, an electrostatic latent image forming means having a charger for uniformly charging the photoreceptor surface and an exposer for exposing the photoreceptor surface charged by the charger to form an electrostatic latent image, a developing means, a transfer means and a fixing means, wherein the electrophotographic photoreceptor includes a support, and a charge generating layer, a charge transport layer and a crosslinked surface layer on the support in this order, and the charger is a scorotron charger having a wire, a shield and a grid coated with a polycondensate of an organic titanate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, an image forming method, and a process capable of suppressing the image density unevenness generated in a low temperature and low humidity environment and enjoying the original durability of a highly durable electrophotographic photoreceptor having a crosslinked surface layer on the outermost surface. It relates to the cartridge.

  Over 10 years have passed since the adoption of the action plan “Agenda 21” established with the hope of handing down the rich global environment to offspring, and it can be said that people's awareness of environmental protection has deepened. For example, it is a familiar example of consciousness change that garbage is sorted and the back paper is used frequently as print paper. At present, the environmental performance of industrial products is becoming more and more important to the public. For this reason, research and development aimed at reducing the environmental load of the electrophotographic photosensitive member are being energetically advanced. In view of the life cycle from the mining of raw materials to disposal of the electrophotographic photosensitive member, it is necessary to promote the life extension of the electrophotographic photosensitive member first.

  Since such an electrophotographic photosensitive member is used as a supply product, there is still room for improvement in resource saving and waste reduction. In order to cope with this, it is important to improve the durability of the photosensitive member by suppressing the wear and the wound of the photosensitive member from the viewpoint of designing and using the photosensitive member.

  Currently, amorphous silicon photoconductors are typical examples of highly durable photoconductors. However, since the manufacturing method is a dry process, the manufacturing cost is high, and the object of use is limited to high-end machines with some exceptions. The high durability of the amorphous silicon photoconductor is considered to have not contributed to the reduction of the environmental load more than the feeling because the ratio of use to the whole is small. In order to reduce the environmental load, it is necessary to reduce the cost in addition to increasing the durability of the photoreceptor because it is necessary to increase the usage ratio. For this purpose, it is advantageous to select a low-cost organic photoreceptor that is highly durable.

  Various proposals have heretofore been made for means for increasing the durability of the organic photoreceptor. For example, the formation of a crosslinked resin layer on the surface of a photoreceptor (see Patent Document 1), the formation of a sol-gel cured film on the surface of a photoreceptor (see Patent Document 2), and the like are promising. The former is advantageous because cracks and cracks are less likely to occur even if a charge transporting component is blended, and the production yield can be reduced. Among these, the radical polymerizable acrylic resin layer is advantageous because it is easy to obtain a tough photoconductor with good sensitivity characteristics. Since these two types of measures adopting a crosslinked structure form a coating film by a plurality of chemical bonds, even if the coating film is stressed and a part of the chemical bond is broken, it does not immediately progress to wear. .

  However, a scorotron charger charging type image forming apparatus equipped with an organic photoconductor is copied and printed at 10 ° C. and 15% RH (low temperature and low humidity environment), and after leaving the photoconductor to stand for about 3 hours or more, it is again. When copying and printing, image density unevenness as shown in FIG. 1 occurs. This is presumed to be caused by local deterioration of the photosensitive member charging ability (only the portion directly under the charger). Such local deterioration is considered to occur because nitrogen oxides and ozone, which are charged products, are chemisorbed (bonded and complexed) with the charge generating material in the photosensitive layer, and this forms space charges. Further, it is also conceivable that nitrogen oxides and ozone are gradually chemically adsorbed from the surface to the inside of the crosslinked surface layer, and this causes a change in the dielectric constant of the crosslinked surface layer.

  In order to prevent such local deterioration, it is conceivable to reduce or detoxify the charged product that is the source of the phenomenon. For example, Patent Document 3 discloses various methods for reducing ozone gas and NOx generated from a charger.

When it is considered that these gases generated in the charging process have an effect on the generation of an abnormal image, a low-temperature and low-humidity environment (hereinafter sometimes referred to as “LL”) and a normal temperature and normal humidity of 25 ° C. and 55% RH. It is expected that the gas concentration varies depending on the environment (hereinafter sometimes referred to as “RR”). In this case, the prior art is an effective measure for solving the problem. However, there is no large difference in the gas concentration generated between the LL environment and the RR environment, and the NOx gas concentration generated from the scorotron charger is proportional to the current flowing through the wire stretched on the charger, and the constant current power pack In the image forming apparatus used, the current flowing through the wire does not fluctuate even when the usage environment changes, so that the NOx gas concentration does not cause an environmental difference.
Therefore, there is no prospect of improving the occurrence of abnormal images even if the amount of gas generated in the charging process is reduced, and the occurrence of image density unevenness at the site directly below the scorotron charger of the photoreceptor that occurs in a low temperature and low humidity environment is effectively achieved. The current situation is that it is still difficult to suppress.

JP 2000-66424 A JP 2000-171990 A JP 2000-259012 A

  An object of the present invention is to solve various problems in the prior art and achieve the following objects. That is, the present invention is a scorotron charger type image forming apparatus equipped with a highly durable electrophotographic photosensitive member having a cross-linked surface layer on the outermost surface, in a portion immediately below the scorotron charger of the photosensitive member generated in a low temperature and low humidity environment. An object of the present invention is to provide an image forming apparatus, an image forming method, and a process cartridge that can effectively suppress the occurrence of uneven image density.

  In order to solve the above-mentioned problems, as a result of repeated investigations by the present inventors, as the scorotron charger is used, the grid gradually becomes brownish, and the stronger this stain, the more severe the occurrence of the previous abnormal image. I found out that When this grid stain was analyzed by ion chromatography, nitrate ions and ammonium ions were detected strongly, and it was found that nitrogen oxides and ammonium salts adhering to the grid had an effect on the occurrence of abnormal images. Further, in a room temperature and normal humidity (RR) environment, an abnormal image does not occur even when the above-mentioned strongly dirty grid is used. From this, it is conceivable that the humidity affects the amount (or amount of residence) of nitrogen oxides or ammonium ions attached to the grid. In fact, there is a correlation between humidity and the detected amounts of nitrate and ammonium ions. The higher the humidity, the lower the detected ion concentration, and moisture in the atmosphere acts as a removal material for grid deposits. I found out that

  From the above knowledge, the present inventors, as a measure for suppressing the adhesion of nitrogen oxides and ammonium salts to the grid, in the low temperature and low humidity (LL) environment, the grid is similar to the normal temperature and normal humidity (RR) environment It has been found that the occurrence of image density unevenness in the region immediately below the scorotron charger of the photoconductor generated in a low-temperature and low-humidity environment can be effectively suppressed.

Means for solving the problems are as follows. That is,
<1> Electrostatic latent image formation having an electrophotographic photosensitive member, a charger for uniformly charging the surface of the photosensitive member, and an exposure device for exposing the charged surface of the photosensitive member to form an electrostatic latent image Development means for developing the electrostatic latent image with toner to form a visible image, transfer means for transferring the visible image to a recording medium, and fixing the transfer image transferred to the recording medium At least fixing means for causing
The electrophotographic photoreceptor has a support, and at least a charge generation layer, a charge transport layer, and a crosslinked surface layer in this order on the support,
In the image forming apparatus, the charger is a scorotron charger having a wire, a shield, and a grid, and the grid in the scorotron charger is coated with a polycondensate of organic titanate.
<2> The image forming apparatus according to <1>, wherein the organic titanate is di-i-propoxy bis (acetylacetonato) titanium.
<3> From the above <1>, the crosslinked surface layer contains a cured product of a tri- or higher functional radical polymerizable compound having no charge transporting structure and a radical polymerizable compound having a monofunctional charge transporting structure. <2> The image forming apparatus according to any one of <2>.
<4> The image forming apparatus according to <3>, wherein the radical polymerizable compound having a monofunctional charge transporting structure is represented by the following structural formula (1).
However, in said structural formula (1), d, e, and f represent the integer of 0 or 1, respectively. R ¹ represents either a hydrogen atom or a methyl group. g and h represent the integer of 0-3. R ² and R ³ represent an alkyl group having 1 to 6 carbon atoms, and when g and h are 2 or more, the alkyl groups may be the same or different from each other. Z represents a single bond, a methylene group, an ethylene group, or a group represented by the following structural formula.
<5> The trifunctional or higher functional radical polymerizable compound having no charge transport structure is at least one selected from trimethylolpropane triacrylate, caprolactone-modified dipentaerythritol hexaacrylate, and dipentaerythritol hexaacrylate The image forming apparatus according to any one of <3> to <4>.
<6> An electrostatic latent image forming step using a charger that uniformly charges the surface of the electrophotographic photosensitive member and an exposure device that exposes the surface of the photosensitive member charged by the charger to form an electrostatic latent image. A developing step for developing the electrostatic latent image with toner to form a visible image; a transferring step for transferring the visible image to a recording medium; and a fixing for fixing the transferred image transferred to the recording medium. Comprising at least a process,
The electrophotographic photoreceptor has a support, and at least a charge generation layer, a charge transport layer, and a crosslinked surface layer in this order on the support,
In the image forming method, the charger is a scorotron charger having a wire, a shield, and a grid, and the grid in the scorotron charger is covered with a polycondensate of organic titanate.
<7> An electrophotographic photosensitive member, a charger for uniformly charging the surface of the electrophotographic photosensitive member, and an electrostatic latent image formed on the electrophotographic photosensitive member are developed with toner to form a visible image. And at least developing means for
The electrophotographic photoreceptor has a support, and on the support, at least a charge generation layer, a charge transport layer, and a crosslinked surface layer in this order,
The charger is a scorotron charger having a wire, a shield, and a grid, and the grid in the scorotron charger is coated with a polycondensate of organic titanate.

In the image forming apparatus of the present invention, the charger is a scorotron charger having a wire, a shield, and a grid, and the grid in the scorotron charger is coated with a polycondensate of organic titanate. In an environment, the grid has a property similar to that in a normal temperature and normal humidity (RR) environment, so that the occurrence of abnormal images can be suppressed and the original durability of the photoreceptor can be enjoyed.
On the other hand, a temporary effect can be seen by coating the grid with a paint in which titanium oxide powder is dispersed. This method is a method similar to Japanese Patent Laid-Open Nos. 2000-259012 and 2001-75443. However, this coating film cannot be said to have sufficient durability against corona discharge to match the durability of the photoreceptor. This is presumably because the binder resin itself carrying titanium oxide is decomposed under the influence of the photo-oxidation catalyst.
Therefore, when an organic titanate was applied to the grid and a sol-gel cured film was formed by heating, it was confirmed that it had high durability and a strong anti-contamination effect even in a low temperature and low humidity environment. This cured film is considered to be able to prevent soiling of the grid due to the photo-oxidation catalytic function by corona discharge light having an emission intensity around 350 nm and the property of high hydrophilicity.

  According to the present invention, conventional problems can be solved, image density unevenness that occurs in a low-temperature and low-humidity environment is suppressed, and the original durability of a highly durable electrophotographic photosensitive member having a crosslinked surface layer on the outermost surface is enjoyed. An image forming apparatus, an image forming method, and a process cartridge can be provided.

(Image forming apparatus and image forming method)
The image forming apparatus of the present invention comprises at least an electrophotographic photosensitive member, an electrostatic latent image forming unit, a developing unit, a transfer unit, and a fixing unit, and other components appropriately selected as necessary. Means, for example, static elimination means, cleaning means, recycling means, control means and the like.
The image forming method of the present invention includes at least an electrostatic latent image forming step, a developing step, a transfer step, and a fixing step, and other steps appropriately selected as necessary, for example, a static elimination step, a cleaning step. A recycling process, a control process, and the like.

  The image forming method of the present invention can be preferably carried out by the image forming apparatus of the present invention, the electrostatic latent image forming step can be performed by the electrostatic latent image forming means, and the developing step is the developing The transfer step can be performed by the transfer unit, the fixing step can be performed by the fixing unit, and the other steps can be performed by the other unit.

-Electrostatic latent image forming step and electrostatic latent image forming means-
The electrostatic latent image forming step is a step of forming an electrostatic latent image on the electrophotographic photosensitive member.
<Electrophotographic photoreceptor>
As the electrophotographic photoreceptor, the electrophotographic photoreceptor of the present invention is used.
There is no restriction | limiting in particular as said electrophotographic photoreceptor, According to the objective, it can select suitably, A single layer structure or a laminated structure may be sufficient, but a laminated structure is preferable.
The electrophotographic photosensitive member having the laminated structure includes a support, and at least a charge generation layer, a charge transport layer, and a crosslinked surface layer in this order on the support, and further includes other layers as necessary. Have.

Here, FIG. 2 is a cross-sectional view schematically showing an example of the layer structure of the electrophotographic photosensitive member of the present invention. The electrophotographic photosensitive member has a charge generation layer 225 and a charge transport layer 226 on a support 221. And a crosslinked surface layer 228 is provided.
FIG. 3 is a cross-sectional view schematically showing another example of the layer structure of the electrophotographic photosensitive member of the present invention. The electrophotographic photosensitive member is interposed between the support 221 and the charge generation layer 225. A pulling layer 224 is provided, and a charge transport layer 226 and a crosslinked surface layer 228 are provided on the charge generation layer 225.

-Crosslinked surface layer-
The crosslinked surface layer means a surface protective layer formed on the outermost surface of the electrophotographic photosensitive member. After the surface protective layer is coated with a crosslinked surface layer coating solution, a resin having a crosslinked structure is formed by a polycondensation reaction. Since the crosslinked surface layer has a crosslinked structure, it has the strongest wear resistance among the layers of the photoreceptor. In addition, since the crosslinkable surface layer is blended with a crosslinkable charge transport material, it exhibits charge transportability similar to that of the charge transport layer.

  The crosslinked surface layer contains a cured product of a tri- or higher functional radical polymerizable compound having no charge transporting structure and a radical polymerizable compound having a monofunctional charge transporting structure, and further if necessary. And other components. As a result, the balance between the sensitivity characteristics of the photoreceptor and high durability can be achieved.

The radical polymerizable compound having a monofunctional charge transporting structure is not particularly limited and may be appropriately selected depending on the intended purpose. The monofunctional charge transporting structure represented by the following structural formula (1) A radical-polymerizable compound having is preferred.
However, in said structural formula (1), d, e, and f represent the integer of 0 or 1, respectively. R ¹ represents either a hydrogen atom or a methyl group. g and h represent the integer of 0-3. R ² and R ³ represent an alkyl group having 1 to 6 carbon atoms, and when g and h are 2 or more, the alkyl groups may be the same or different from each other. Z represents a single bond, a methylene group, an ethylene group, or a group represented by the following structural formula.
Examples of the alkyl group having 1 to 6 carbon atoms in R ² and R ³ include a methyl group, an ethyl group, a propyl group, and a butyl group.

  The content of the radically polymerizable compound having a monofunctional charge transporting structure in the crosslinked surface layer is preferably 20 to 80% by mass, and more preferably 30 to 70% by mass.

The trifunctional or higher functional radical polymerizable compound having no charge transport structure is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include trimethylolpropane triacrylate (TMPTA) and trimethylolpropane. Trimethacrylate, trimethylolpropane alkylene-modified triacrylate, trimethylolpropane ethyleneoxy-modified (hereinafter sometimes referred to as “EO-modified”) triacrylate, trimethylolpropane propyleneoxy-modified (hereinafter referred to as “PO-modified”) A) triacrylate, trimethylolpropane caprolactone-modified triacrylate, trimethylolpropane alkylene-modified trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, glycerol epichlorohydrin modified triacrylate, glycerol EO modified triacrylate, glycerol PO modified triacrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), di Pentaerythritol caprolactone modified hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkylated dipentaerythritol pentaacrylate, alkylated dipentaerythritol tetraacrylate, alkylated dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxy Tetraacrylate, EO modified phosphate Acrylate, 2,2,5,5, - such as tetrahydroxy methyl cyclopentanone tetraacrylate and the like. These may be used individually by 1 type and may use 2 or more types together.
Among these, trimethylolpropane triacrylate, caprolactone-modified dipentaerythritol hexaacrylate, and dipentaerythritol hexaacrylate are particularly preferable.
As the trifunctional or higher functional radical polymerizable compound having no charge transporting structure, an appropriately synthesized compound or a commercially available product may be used. Examples of the commercially available products include KAYARD DPCA series and KAYARD DPHA series manufactured by Nippon Kayaku Co., Ltd.
The content of the trifunctional or higher functional radical polymerizable compound having no charge transport structure in the crosslinked surface layer is preferably 20 to 80% by mass, and more preferably 30 to 70% by mass.

In addition to the above components, the cross-linked surface layer has a monofunctional or bifunctional radical polymerization for the purpose of adding functions such as viscosity adjustment during coating, stress relaxation of the cross-linked surface layer, lower surface energy, and reduction of friction coefficient. Monomers, radical polymerizable oligomers and the like can be used in combination.
In addition, in order to efficiently advance the curing reaction between a radically polymerizable compound having 3 or more functional groups having no charge transporting structure and a radically polymerizable compound having a monofunctional charge transporting structure, a thermal polymerization initiator, photopolymerization It is preferable to contain a polymerization initiator such as an initiator.

  Examples of the thermal polymerization initiator include 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5- Di (peroxybenzoyl) hexyne-3, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, lauroyl peroxide, 2,2-bis (4,4-di-t-butylperoxide Peroxide initiators such as oxycyclohexyl) propane; azobisisobutylnitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid, etc. Examples thereof include azo initiators.

Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and 4- (2-hydroxyethoxy) phenyl. -(2-hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1,2-hydroxy-2-methyl-1-phenylpropan-1-one Acetophenone-based or ketal-based photopolymerization of 2-methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, etc. Initiator, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin iso Benzoin ether photopolymerization initiators such as tilether, benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone, Benzophenone photopolymerization initiators such as 1,4-benzoylbenzene, thioxanthones such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone Examples of photopolymerization initiators and other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethyl Benzoylphenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, Examples thereof include 10-phenanthrene, acridine compounds, triazine compounds, and imidazole compounds.
Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. Examples thereof include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4′-dimethylaminobenzophenone, and the like.

  The content of the polymerization initiator is preferably 0.5 to 40 parts by mass and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the total amount of compounds having radical polymerizability.

In the cross-linked surface layer, an antioxidant, a plasticizer, a lubricant, a low molecular compound such as a UV absorber, a leveling agent, a polymer compound described in the charge transport layer, or the like may be added as necessary. it can. These compounds can be used alone or as a mixture of two or more. When the low molecular weight compound and the leveling agent are used in combination, sensitivity deterioration may occur. For this reason, 0.1-20 mass% is preferable and, as for the addition amount in these said bridge | crosslinking surface layers, 0.1-10 mass% is more preferable. The addition amount of the leveling agent is preferably 0.1 to 5% by mass.
The crosslinked surface layer may be blended with the same binder resin as the charge transport layer for the purpose of adjusting the adhesion work with the charge transport layer.

The cross-linked surface layer is formed by applying a cross-linked surface layer coating solution containing at least a trifunctional or higher-functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. It is formed by applying and curing on. When the radically polymerizable monomer is a liquid, the cross-linked surface layer coating liquid can be applied by dissolving other components in the liquid, but if necessary, it is diluted with a solvent and applied. .
As the solvent, those capable of sufficiently dissolving the monomer are preferable. For example, in addition to ethers, aromatics, halogens, esters, cellosolves such as ethoxyethanol; 1-methoxy-2-propanol And propylene glycols. Among these, methyl ethyl ketone, tetrahydrofuran, cyclohexanone, and 1-methoxy-2-propanol are particularly preferable because they have a lower environmental impact than chlorobenzene, dichloromethane, toluene, and xylene. These may be used individually by 1 type and may use 2 or more types together.

  The coating method of the crosslinked surface layer coating liquid is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the dipping method, spray coating method, ring coating method, roll coater method, gravure coating method , Nozzle coating method, screen printing method, and the like. In many cases, since the pot life of the coating liquid is not long, a means capable of coating a necessary amount with a small amount of paint is advantageous in consideration of the environment and cost. Among these, the spray coating method and the ring coating method are particularly preferable.

When the crosslinked surface layer is cured, a UV irradiation light source such as a high-pressure mercury lamp or a metal halide lamp having an emission wavelength mainly in ultraviolet light can be used. In addition, a visible light source can be selected in accordance with the absorption wavelength of the radical polymerizable substance or the photopolymerization initiator. The amount of irradiation light is preferably 50 to 1000 mW / cm ² . When the irradiation light amount is less than 50 mW / cm ² , the curing reaction may take time, and when it exceeds 1000 mW / cm ² , the progress of the reaction becomes non-uniform, and the surface of the crosslinkable charge transport layer is locally May occur, or many unreacted residues and reaction termination ends may occur. In addition, the internal stress increases due to rapid crosslinking, which may cause cracks and film peeling.

  The thickness of the crosslinked surface layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1 to 10 μm, and more preferably 2 to 8 μm.

-Support-
There is no restriction | limiting in particular as said support body, Although it can select suitably according to the objective, The thing which shows the electroconductivity whose volume resistance is 10 < ¹⁰ > ohm * cm or less is suitable.
The material, shape, and size of the support are not particularly limited, and any of a plate shape, a drum shape, or a belt shape can be used. For example, aluminum, nickel, chromium, nichrome, copper, gold, and the like can be used. Metals such as silver and platinum, metal oxides such as tin oxide and indium oxide by vapor deposition or sputtering, film or cylindrical plastic, paper coated, or plates made of aluminum, aluminum alloy, nickel, stainless steel, etc. And pipes that have been surface-treated by cutting, super-finishing, polishing, etc. after forming them into pipes by a method such as the drawing ironing method, the impact ironing method, the extracted ironing method, the extracted drawing method, or the cutting method. . Further, an endless nickel belt and an endless stainless steel belt disclosed in JP-A-52-36016 can also be used as a support.

In addition to the above, it is also possible to use a conductive layer formed by dispersing conductive powder on an appropriate binder resin and coating the support.
Examples of the material of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, or metal oxide such as conductive tin oxide and ITO. Examples thereof include powder. Examples of the binder resin include polystyrene resin, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester resin, polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer. Polymer, polyvinyl acetate resin, polyvinylidene chloride resin, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl toluene resin, poly-N-vinyl carbazole resin, acrylic resin , Silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin and the like.
The conductive layer can be formed by applying a coating solution obtained by dissolving or dispersing the conductive powder and a binder resin in a solvent on a support. Examples of the solvent include tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene, and the like.

  In addition, the conductive powder is contained in the cylindrical substrate in polyvinyl chloride resin, polypropylene resin, polyester resin, polystyrene resin, polyvinylidene chloride resin, polyethylene resin, chlorinated rubber, polytetrafluoroethylene fluororesin, or the like. It is also preferable to provide a conductive layer with a heat shrinkable tube.

-Charge generation layer-
The charge generation layer has a function of generating charges upon exposure, and includes at least a charge generation material and a binder resin, and further includes other components as necessary.
As the charge generating substance, inorganic materials and organic materials can be used.
The inorganic material is not particularly limited and can be appropriately selected from known materials according to the purpose. Examples thereof include metal phthalocyanines such as titanyl phthalocyanine and chlorogallium phthalocyanine, metal-free phthalocyanines, azulenium salt pigments, squares, and the like. Rickic acid methine pigment, symmetric or asymmetric azo pigment having carbazole skeleton, symmetric or asymmetric azo pigment having triphenylamine skeleton, symmetric or asymmetric azo pigment having fluorenone skeleton, perylene pigment, etc. Is mentioned. These may be used individually by 1 type and may use 2 or more types together.
Among these, metal phthalocyanines, symmetric or asymmetric azo pigments having a fluorenone skeleton, symmetric or asymmetric azo pigments having a triphenylamine skeleton, and perylene pigments are particularly preferable because of their high quantum efficiency of charge generation. .

  The organic material is not particularly limited and may be appropriately selected from known materials according to the purpose. For example, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azurenium salt pigments, squaric acid methine Pigment, azo pigment having carbazole skeleton, azo pigment having triphenylamine skeleton, azo pigment having diphenylamine skeleton, azo pigment having dibenzothiophene skeleton, azo pigment having fluorenone skeleton, azo pigment having oxadiazole skeleton, bis Azo pigments having a stilbene skeleton, azo pigments having a distyryl oxadiazole skeleton, azo pigments having a distyryl carbazole skeleton, perylene pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenyl Enirumetan pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, indigoid pigments, and bisbenzimidazole pigments. These may be used individually by 1 type and may use 2 or more types together.

There is no restriction | limiting in particular as said binder resin, According to the objective, it can select suitably, For example, a polyamide resin, a polyurethane resin, an epoxy resin, a polyketone resin, a polycarbonate resin, a silicone resin, an acrylic resin, a polyvinyl butyral resin, polyvinyl Formal resin, polyvinyl ketone resin, polystyrene resin, poly-N-vinyl carbazole resin, polyacrylamide resin, and the like can be given. These may be used individually by 1 type and may use 2 or more types together. Among these, polyvinyl butyral resin is particularly preferable.
In addition to the binder resin described above, the charge generation layer binder resin may be a polymer charge transport material having a charge transport function, such as (1) an arylamine skeleton, a benzidine skeleton, a hydrazone skeleton, a carbazole skeleton, or a stilbene. Polymer materials such as polycarbonate, polyester, polyurethane, polyether, polysiloxane, and acrylic resin having a skeleton and a pyrazoline skeleton, and (2) a polymer material having a polysilane skeleton can be used.

  Specific examples of the above (1) include JP-A-01-001728, JP-A-01-009964, JP-A-01-013061, JP-A-01-019049, JP-A-01-241559. JP, 04-011627, JP 04-175337, JP 04-183719, JP 04-22514, JP 04-230767, JP 04-320420, JP 05-232727, JP 05-310904, JP 06-234836, JP 06-234837, JP 06-234838, JP 06-234839, JP JP 06-234840, JP 06-234841 A, JP 06-239049 A JP-A 06-236050, JP-A 06-236051, JP-A 06-295077, JP-A 07-056374, JP-A 08-176293, JP 08-208820, JP 08-21640 A, JP 08-253568 A, JP 08-269183 A, JP 09-062019 A, JP 09-038883 A, JP 09-71642 A, JP JP 09-87376, JP 09-104746, JP 09-110974, JP 09-110976, JP 09-157378, JP 09-221544, JP 09-09. No. 227669, JP 09-235367 A, JP 09-241369 JP-A 09-268226, JP-A 09-272735, JP-A 09-302084, JP-A 09-302085, JP-A 09-328539, and the like. Materials.

Specific examples of the above (2) include, for example, those described in JP-A-63-285552, JP-A-05-19497, JP-A-05-70595, JP-A-10-73944, and the like. Examples are polysilylene polymers.
The content of the binder resin is preferably 0 to 500 parts by mass and more preferably 10 to 300 parts by mass with respect to 100 parts by mass of the charge generation material. The binder resin may be added either before or after dispersion.

The charge generation layer may contain a low molecular charge transport material.
The low molecular charge transport material includes a hole transport material and an electron transport material.
Examples of the electron transporting 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 -Trinitrodibenzothiophene-5,5-dioxide, diphenoquinone derivatives and the like. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the hole transport material include 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, and the like, and other known materials. These may be used individually by 1 type and may use 2 or more types together.

As a method for forming the charge generation layer, a vacuum thin film preparation method and a casting method from a solution dispersion system can be mentioned.
As the vacuum thin film production method, for example, a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD method, or the like is used.
As the casting method, the inorganic or organic charge generating material, and optionally binder resin, tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclopentanone, anisole, xylene, methyl ethyl ketone It can be formed by dispersing with a ball mill, attritor, sand mill, bead mill or the like using a solvent such as acetone, ethyl acetate, butyl acetate, etc., and applying the solution after diluting the dispersion appropriately. Moreover, leveling agents, such as a dimethyl silicone oil and a methylphenyl silicone oil, can be added as needed. The application can be performed by dip coating, spray coating, bead coating, ring coating, or the like.

  The thickness of the charge generation layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.01 to 5 μm. In this case, if it is necessary to reduce the residual potential or increase the sensitivity, these characteristics are often improved by increasing the thickness of the charge generation layer. On the other hand, the chargeability often deteriorates, such as the charge charge retention and space charge formation. From these balances, the thickness of the charge generation layer is more preferably 0.05 to 2 μm.

-Charge transport layer-
The charge transport layer is a layer intended to hold a charged charge and to couple the charge generated and separated in the charge generation layer by exposure to the charged charge held by movement. In order to achieve the purpose of holding the charged charge, it is required that the electric resistance is high. Further, in order to achieve the purpose of obtaining a high surface potential with the charged charge that has been held, it is required that the dielectric constant is small and the charge mobility is good.

  The charge transport layer contains at least a charge transport material and a binder resin, and further contains other components as necessary.

Examples of the charge transport material include a hole transport material, an electron transport material, and a polymer charge transport material.
Examples of the electron transporting material (electron accepting material) include chloranil, 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-4H-indeno [1,2-b] thiophene-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, and the like. These may be used individually by 1 type and may use 2 or more types together.

Examples of the hole transport material (electron donating material) include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4 -Dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives, etc. It is done.
These may be used individually by 1 type and may use 2 or more types together.

Examples of the polymer charge transport material include those having the following structure.
Examples of (a) a polymer having a carbazole ring include, for example, poly-N-vinylcarbazole, JP-A-50-82056, JP-A-54-9632, JP-A-54-11737, JP-A-5-11737. Examples thereof include compounds described in JP-A-4-175337, JP-A-4-183719, and JP-A-6-234841.
(B) Examples of the polymer having a hydrazone structure include, for example, JP-A-57-78402, JP-A-61-20953, JP-A-61-296358, JP-A-1-134456, Compounds described in Kaihei 1-179164, JP-A-3-180851, JP-A-3-180852, JP-A-3-50555, JP-A-5-310904, and JP-A-6-234840 Etc. are exemplified.
(C) Examples of the polysilylene polymer include, for example, JP-A-63-285552, JP-A-1-88461, JP-A-4-264130, JP-A-4-264131, and JP-A-4-264132. Examples thereof include compounds described in JP-A-4-264133 and JP-A-4-289867.
(D) As a polymer having a triarylamine structure, for example, N, N-bis (4-methylphenyl) -4-aminopolystyrene, JP-A-1-134457, JP-A-2-282264, Examples thereof include compounds described in Kaihei 2-304456, JP-A-4-133605, JP-A-4-133066, JP-A-5-40350, and JP-A-5-202135.
(E) As other polymers, for example, a formaldehyde condensation polymer of nitropyrene, JP-A-51-73888, JP-A-56-15049, JP-A-6-234363, JP-A-6-234837 And the compounds described in Japanese Patent Publication No.

  In addition to the above, the polymer charge transporting material includes, for example, a polycarbonate resin having a triarylamine structure, a polyurethane resin having a triarylamine structure, a polyester resin having a triarylamine structure, and a triarylamine structure. And a polyether resin. Examples of the polymer charge transporting material include JP-A 64-1728, JP-A 64-13061, JP-A 64-19049, JP-A-4-11627, JP-A 4-116627. JP 2225014, JP 4-230767, JP 4-320420, JP 5-232727, JP 7-56374, JP 9-127713, JP 9-222740. And compounds described in JP-A-9-265197, JP-A-9-211877, JP-A-9-30495, and the like.

Examples of the polymer having an electron donating group include not only the above-mentioned polymer but also a copolymer with a known monomer, a block polymer, a graft polymer, a star polymer, It is also possible to use a crosslinked polymer having an electron donating group as disclosed in JP-A-109406.
The polymer charge transport material is a material suitable for preventing the poor curing of the crosslinked surface layer with less oozing into the crosslinked surface layer when laminating the curable protective layer compared to the low molecular charge transport material. It is. In addition, since the charge transport material has a high heat resistance, it is advantageous in that it is less deteriorated by the heat of curing when the crosslinked surface layer is formed.

  Examples of the binder resin include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyethylene resin, polyvinyl chloride resin, polyvinyl acetate resin, polystyrene resin, phenol resin, epoxy resin, polyurethane resin, and polyvinylidene chloride resin. Alkyd resins, silicone resins, polyvinyl carbazole resins, polyvinyl butyral resins, polyvinyl formal resins, polyacrylate resins, polyacrylamide resins, phenoxy resins, and the like are used. These may be used individually by 1 type and may use 2 or more types together. Among these, polycarbonate resin is particularly preferable.

When an electrically inactive polymer compound is used for modifying the charge transport layer, a cardo polymer type polyester having a bulky skeleton such as fluorene, a polyester such as polyethylene terephthalate or polyethylene naphthalate, or a C type polycarbonate A polycarbonate in which the 3,3 ′ portion of the phenol component is alkyl-substituted with respect to the bisphenol-type polycarbonate, a polycarbonate in which the geminal methyl group of bisphenol A is substituted with a long-chain alkyl group having 2 or more carbon atoms, biphenyl Or polycarbonate having a long-chain alkyl skeleton such as polycarbonate having a biphenyl ether skeleton, polycaprolactone, polycaprolactone (for example, described in JP-A-7-292095), acrylic resin, polystyrene, hydrogenation Butadiene is effective.
Here, the electrically inactive polymer compound refers to a polymer compound that does not include a chemical structure exhibiting photoconductivity such as a triarylamine structure.
These polymer compounds can be used alone or as a mixture of two or more kinds, or as a copolymer composed of two or more of these raw material monomers, and further copolymerized with a charge transport material.

  When a low molecular charge transport material is used, the amount used is preferably 40 to 200 parts by weight, more preferably 70 to 100 parts by weight, per 100 parts by weight of the charge transport component. In the case of using a polymer charge transport material, the resin component is preferably 0 to 200 parts by weight, particularly preferably 80 to 150 parts by weight, based on 100 parts by weight of the charge transport component. It is done.

In addition, when two or more kinds of charge transport materials are contained in the charge transport layer, it is preferable that the difference in ionization potential is smaller. Specifically, by setting the difference in ionization potential to 0.10 eV or less, It is possible to prevent the transport material from becoming a charge trap of the other charge transport material.
As for the relationship between the ionization potentials, the difference between the charge transporting material contained in the charge transporting layer and the curable charge transporting material described later is preferably 0.10 eV or less.
In addition, the ionization potential value of the charge transport material is a numerical value obtained by measuring by a general method using an atmospheric pressure ultraviolet photoelectron analyzer AC-1 manufactured by Riken Keiki Co., Ltd.
In order to satisfy high sensitivity, the amount of the charge transport component is preferably 70 parts by mass or more. Further, as the charge transport material, α-phenylstilbene compound, benzidine compound, butadiene compound monomer, dimer, and polymer charge transport material having these structures in the main chain or side chain are materials having high charge mobility. Is useful.

  The charge transport layer can be formed by dissolving or dispersing these charge transport materials and a binder resin in an appropriate solvent, and applying and drying them. In addition to the charge transport material and the binder resin, an appropriate amount of additives such as a plasticizer, an antioxidant, and a leveling agent may be added to the charge transport layer as necessary.

As the solvent used for coating the charge transport layer, the same solvent as the charge generation layer can be used, but a solvent that dissolves the charge transport material and the binder resin well is suitable. These solvents may be used alone or in combination of two or more. The charge transport layer can be formed by the same coating method as that for the charge generation layer.
As said plasticizer, what is used as a plasticizer of general resins, such as dibutyl phthalate and dioctyl phthalate, can be used as it is, and the usage-amount is 0-30 with respect to 100 mass parts of said binder resins. Part by mass is preferred.
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. The amount used is 100 mass of the binder resin. 0-1 mass part is preferable with respect to a part.

Since the cross-linked surface layer is laminated on the charge transport layer, the thickness of the charge transport layer in this configuration does not need to be designed to increase the thickness of the charge transport layer in consideration of film scraping in actual use. Yes, thinning is possible.
The thickness of the charge transport layer is preferably 15 to 40 μm, and more preferably 15 to 30 μm for the purpose of ensuring the sensitivity and chargeability required for practical use.

-Undercoat layer-
Between the support and the photosensitive layer, if necessary, for the purpose of improving adhesion, preventing moire, improving coatability and adhesion of the upper layer, and preventing charge injection from the support. As an example, an undercoat layer may be provided.
The undercoat layer generally contains a resin as a main component, but these resins are resins having a high solvent resistance with respect to a general organic solvent in consideration of applying a photosensitive layer thereon with a solvent. It is preferable. Examples of the resin include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane resins, melamine resins, phenol resins, alkyd-melamine resins, Examples thereof include a curable resin that forms a three-dimensional network structure, such as an epoxy resin.

In addition, fine particles such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, and indium oxide can be added to the undercoat layer in order to prevent moire and reduce residual potential. Among these, titanium oxide is particularly preferable.
The fine particles are dispersed by a ball mill, an attritor, a sand mill or the like using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, or butanone to obtain a coating material in which the dispersion and the resin component are mixed.
The undercoat layer is formed by depositing the above-mentioned paint on a support by a dip coating method, a spray coating method or the like and, if necessary, heat curing. Further, it may be applied two or more times.
The undercoat layer may have a multilayer structure by changing two or more kinds of resins. By doing so, it may be possible to enhance the prevention of charge leakage.
The thickness of the undercoat layer is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably about 2 to 5 μm, and if the accumulation of the residual potential of the photoreceptor is increased, the thickness is preferably less than 3 μm. More preferred.

  In addition, in the electrophotographic photoreceptor of the present invention, in order to improve environmental resistance, a crosslinked surface layer, a charge generation layer, a charge transport layer, an undercoat layer, in particular, for the purpose of preventing a decrease in sensitivity and an increase in residual potential. An antioxidant can be added to each layer.

Examples of the antioxidant include phenolic compounds, paraphenylenediamines, organic sulfur compounds, and organic phosphorus compounds.
Examples of the phenol compound include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2,2'-methylene-bis- (4-ethyl- 6-t-butylphenol), 4,4′-thiobis- (3-methyl-6-tert-butylphenol), 4,4′-butylidenebis- (3-methyl-6-tert-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-hydroxy Ben ) Benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis (4′-hydroxy-3 ′) -T-butylphenyl) butyric acid] cricol ester, tocopherols and the like.
Examples of the paraphenylenediamines include N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl- Examples include p-phenylenediamine, N, N′-di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine, and the like.
Examples of the hydroquinones include 2,5-di-t-octyl hydroquinone, 2,6-didodecyl hydroquinone, 2-dodecyl hydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methyl. Examples include hydroquinone and 2- (2-octadecenyl) -5-methylhydroquinone.
Examples of the organic sulfur compounds include dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like. .
Examples of the organic phosphorus compounds include triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.
These compounds are known as antioxidants such as rubbers, plastics, oils and fats, and commercially available products can be easily obtained.
The addition amount of the antioxidant is preferably 0.01 to 10% by mass with respect to the total mass of the layer to be added.

  The formation of the electrostatic latent image can be performed, for example, by uniformly charging the surface of the electrophotographic photosensitive member and then performing imagewise exposure, and can be performed by the electrostatic latent image forming unit. it can. The electrostatic latent image forming means includes at least a charger that uniformly charges the surface of the electrophotographic photosensitive member and an exposure device that exposes the surface of the electrophotographic photosensitive member imagewise.

The charging can be performed, for example, by applying a voltage to the surface of the electrophotographic photosensitive member using the charger.
As the charger, a scorotron charger having a wire, a shield, and a grid is used.

For example, as shown in FIG. 4, the scorotron charger includes a shield 231, a grid 233, and wires 234, and a photoconductor 235 is provided opposite to the shield 231.
The shield 231 is a metal plate such as stainless steel, and is installed to face the wire 234.
The grid 233 is obtained by processing a plurality of wires or a thin metal plate having a thickness of about 0.1 to 0.5 mm, and is disposed so as to face the photoconductor 235 at a distance of 1.5 to 3 mm.
The grid 233 is maintained at a constant voltage of 600 to 900 V by a high voltage circuit. The high voltage circuit includes a voltage generation circuit or a circuit using a constant voltage element such as a Zener diode or a varistor.
The grid is coated with a sol-gel cured film of organic titanate. There is no restriction | limiting in particular as said organic titanate, According to the objective, it can select suitably, What was synthesize | combined suitably may be used and a commercial item may be used. Examples of the commercially available products include A-1 (tetra-i-propoxy titanium), B-1 (tetra-n-butoxy titanium), and TOT (tetrakis (2-ethylhexyloxy) titanium) marketed by Nippon Soda Co., Ltd. ), TST (tetrastearyloxytitanium), T-50 (di-i-propoxy bis (acetylacetonato) titanium), TAT (di-n-butoxy bis (triethanolaminato) titanium) and the like. . These may be used individually by 1 type and may use 2 or more types together. Among these, T-50 (di-i-propoxy bis (acetylacetonato) titanium) is advantageous in that it has good wettability with the grid in addition to the performance of preventing pollution, and is easy to apply and advantageous. Particularly preferred.
The film formation may be performed using an electric furnace after spraying organic titanate on a grid heated to 200 ° C. to 600 ° C., or spraying or immersing the organic titanate solution on the grid.
There is no restriction | limiting in particular in the thickness of the said film, Although it can select suitably according to the objective, 0.1-5 micrometers is preferable.

  The wire 234 is driven at a constant current of 100 to 600 μA by a constant current power source. At this time, the potential of the wire 234 is 4 to 8 kV, and corona discharge is generated between the shield 231 and the wire 234.

The exposure can be performed, for example, by exposing the surface of the electrophotographic photosensitive member imagewise using the exposure device.
The exposure device is not particularly limited as long as it can perform imagewise exposure on the surface of the electrophotographic photosensitive member charged by the charger, and can be appropriately selected according to the purpose. However, various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system can be used.
In the present invention, an optical backside system that performs imagewise exposure from the backside of the electrophotographic photosensitive member may be employed.

-Development process and development means-
The developing step is a step of developing the electrostatic latent image using a toner or a developer to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using the toner or the developer of the present invention, and can be performed by the developing unit.
The developing means is not particularly limited as long as it can be developed using, for example, toner or developer, and can be appropriately selected from known ones. For example, the toner or developer is accommodated, and Preferable examples include those having at least a developing unit capable of bringing the toner or the developer into contact or non-contact with the electrostatic latent image.

  The developing unit may be a dry developing type, a wet developing type, a single color developing unit, or a multi-color developing unit. For example, a toner having a stirrer for charging the toner or the developer by frictional stirring and a rotatable magnet roller is preferable.

  In the developing device, for example, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. . Since the magnet roller is disposed in the vicinity of the photoconductor, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is applied to the surface of the photoconductor by an electric attractive force. Moving. As a result, the electrostatic latent image is developed with the toner to form a visible image with the toner on the surface of the photoreceptor.

  The developer accommodated in the developing device is a developer containing toner, but the developer may be a one-component developer or a two-component developer.

-Transfer process and transfer means-
The transfer step is a step of transferring the visible image onto a recording medium. After the primary transfer of the visible image onto the intermediate transfer member using an intermediate transfer member, the visible image is transferred onto the recording medium. A primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer body using two or more colors, preferably full color toner as the toner, and a composite transfer image; A mode including a secondary transfer step of transferring the transfer image onto the recording medium is more preferable.
The transfer can be performed, for example, by charging the photoreceptor using a transfer charger, and can be performed by the transfer unit. The transfer means includes a primary transfer means for transferring a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto a recording medium. Embodiments are preferred.
The intermediate transfer member is not particularly limited and may be appropriately selected from known transfer members according to the purpose. For example, a transfer belt and the like are preferable.

The transfer unit (the primary transfer unit and the secondary transfer unit) preferably includes at least a transfer unit that peels and charges the visible image formed on the photoconductor toward the recording medium. There may be one transfer means or two or more transfer means.
Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is typically plain paper, but is not particularly limited as long as it can transfer an unfixed image after development, and can be appropriately selected according to the purpose. PET for OHP A base or the like can also be used.

The fixing step is a step of fixing the visible image transferred to the recording medium using a fixing device, and may be performed each time the toner of each color is transferred to the recording medium, or for the toner of each color. You may perform this simultaneously in the state which laminated | stacked this.
There is no restriction | limiting in particular as said fixing device, Although it can select suitably according to the objective, A well-known heating-pressing means is suitable. Examples of the heating and pressing means include a combination of a heating roller and a pressure roller, a combination of a heating roller, a pressure roller, and an endless belt.
The heating in the heating and pressing means is usually preferably 80 to 200 ° C.
In the present invention, for example, a known optical fixing device may be used together with or in place of the fixing step and the fixing unit depending on the purpose.

The neutralization step is a step of performing neutralization by applying a neutralization bias to the electrophotographic photosensitive member, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited, and may be appropriately selected from known neutralizers as long as it can apply a neutralization bias to the electrophotographic photosensitive member. For example, a neutralization lamp is preferably used. Can be mentioned.

The cleaning step is a step of removing the toner remaining on the electrophotographic photosensitive member, and can be suitably performed by a cleaning unit.
The cleaning means is not particularly limited as long as it can remove the electrophotographic toner remaining on the electrophotographic photosensitive member, and can be appropriately selected from known cleaners. For example, a magnetic brush cleaner Suitable examples include electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, web cleaners, and the like.

The recycling step is a step of recycling the toner removed by the cleaning step to the developing unit, and can be suitably performed by the recycling unit.
There is no restriction | limiting in particular as said recycling means, A well-known conveyance means etc. are mentioned.

The control step is a step of controlling each of the steps, and can be suitably performed by a control unit.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

  As the image forming apparatus, a desktop type or a floor type using an indirect electrophotographic method (the xerographic method), such as a facsimile, a laser printer, an electrophotographic copying machine, a direct plate making machine, and a complex machine thereof, which are widely spread. In general, the image forming apparatus includes an electrophotographic photosensitive member (or an image carrier), a charging unit, an image exposing unit, a developing unit, a transferring unit, a separating unit, a cleaning unit, a discharging unit, a fixing unit, and a copy sheet (recording medium). A paper feed tray, a paper discharge tray, and the like are provided.

Here, FIG. 5 shows a schematic diagram of an image forming apparatus using an electrophotographic system.
As the electrophotographic photoreceptor 1 used for image formation, the above-described stacked organic photoreceptor is used.
Charging is performed by charging means 2 disposed opposite to the photoreceptor 1.
As the charging means 2, a corona charging device is used. The charging potential of the photoreceptor is set to about -400 to -8000V. In the corona charging device, a 40 to 60 μm discharge wire (for example, tungsten wire) is placed in a U-shaped shield case, a DC voltage of −4000 to −7000 V is applied, and 8 to 10 mm from the photoconductor. It is a device that is charged by being silently discharged at a certain distance. Since a scorotron charger is used as the corona charging device, a grid is installed to make the charging potential uniform. This grid is coated with a sol-gel cured film of organic titanate.

After the photoreceptor 1 is uniformly charged, the original image and the signal from the personal computer are irradiated with a dot pattern by the image exposure means 3 comprising a CCD, LD element or LED element, polygon mirror, filter, cylindrical lens, etc. As a result, an electrostatic latent image (light / dark potential difference) of a digital pattern is formed on the photoreceptor 1.
The electrostatic latent image is developed by developing means 4 using a magnet brush developing method.
The developing means contains a magnetic powder called a carrier having an average particle size of about 40 to 80 μm and a developer composed of toner having a particle size of about 4 to 10 μm, and the toner concentration is set to about 3 to 8% by mass. Is done. A developing bias is applied to the developing means for development.

  The toner used for the developer includes a pulverized toner manufactured by a mechanical manufacturing method and a polymerized toner manufactured by a chemical manufacturing method (such as a suspension polymerization method or an emulsion polymerization method). In recent years, the amount of carbon dioxide generated during production tends to be small, and the use of polymerized toner, which is advantageous for reducing the environmental burden, tends to increase.

The toner image obtained by the development is transferred onto the recording medium (copy paper) 311 conveyed from the paper feed tray 310 by the transfer means 5 to which a voltage opposite to the toner band electrode is applied, and the fixing means 9. And is fixed to a hard copy 313 and discharged to a discharge tray 312.
After the transfer, the residual toner on the photosensitive member is cleaned by a cleaning unit 7 including a cleaning blade 371 using a rubber-like elastic member as a blade, and then the entire surface of the photosensitive member is irradiated by a neutralizing unit 8 so that an internal latent image is neutralized. Is electrically initialized and a series of copying cycles is completed.

  The image forming apparatus is not limited to the configuration shown in FIG. 5, and the image forming apparatus prints through a belt-shaped photoconductor 1, color print with the photoconductor in a tandem layout, or an intermediate transfer body. Is also used.

  Further, the image forming means as described above may be fixedly incorporated in a copying machine, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge.

Next, another mode for carrying out the image forming method of the present invention by the image forming apparatus of the present invention will be described with reference to FIG. The tandem image forming apparatus shown in FIG. 6 is a tandem type color image forming apparatus. The tandem image forming apparatus includes a copying apparatus main body 150, a paper feed table 200, a scanner 300, and an automatic document feeder (ADF) 400.
The copying apparatus main body 150 is provided with an endless belt-like intermediate transfer member 50 at the center. The intermediate transfer member 50 is stretched around the support rollers 14, 15 and 16, and can be rotated clockwise in FIG. 6. An intermediate transfer member cleaning device 17 for removing residual toner on the intermediate transfer member 50 is disposed in the vicinity of the support roller 15. The intermediate transfer member 50 stretched between the support roller 14 and the support roller 15 is a tandem type in which four image forming units 18 of yellow, cyan, magenta, and black are arranged to face each other along the conveyance direction. A developing device 120 is disposed. An exposure device 21 is disposed in the vicinity of the tandem developing device 120. A secondary transfer device 22 is disposed on the side of the intermediate transfer member 50 opposite to the side on which the tandem developing device 120 is disposed. In the secondary transfer device 22, a secondary transfer belt 24, which is an endless belt, is stretched around a pair of rollers 23, and the transfer paper conveyed on the secondary transfer belt 24 and the intermediate transfer body 50 are in contact with each other. Is possible. A fixing device 25 is disposed in the vicinity of the secondary transfer device 22. The fixing device 25 includes a fixing belt 26 that is an endless belt, and a pressure roller 27 that is pressed against the fixing belt 26.
In the tandem image forming apparatus, a sheet reversing device 28 for reversing the transfer paper for image formation on both sides of the transfer paper is disposed in the vicinity of the secondary transfer device 22 and the fixing device 25. Yes.

  Next, formation of a full color image (color copy) using the tandem image forming apparatus will be described. That is, first, a document is set on the document table 130 of the automatic document feeder (ADF) 400, or the automatic document feeder 400 is opened and the document is set on the contact glass 32 of the scanner 300. 400 is closed.

  When a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32, and then the document is set on the contact glass 32. Immediately after that, the scanner 300 is driven, and the first traveling body 33 and the second traveling body 34 travel. At this time, light from the light source is irradiated by the first traveling body 33 and reflected light from the document surface is reflected by the mirror in the second traveling body 34 and is received by the reading sensor 36 through the imaging lens 35 to be color. An original (color image) is read and used as black, yellow, magenta, and cyan image information.

  Each image information of black, yellow, magenta and cyan is stored in each image forming means 18 (black image forming means, yellow image forming means, magenta image forming means and cyan image forming means in the tandem image forming apparatus. ) And black, yellow, magenta and cyan toner images are formed in the respective image forming means. That is, each of the image forming means 18 (black image forming means, yellow image forming means, magenta image forming means, and cyan image forming means) in the tandem image forming apparatus is respectively photosensitive as shown in FIG. On the basis of the body 10 (the black photoreceptor 10K, the yellow photoreceptor 10Y, the magenta photoreceptor 10M, and the cyan photoreceptor 10C), the charger 60 that uniformly charges the photoreceptor, and each color image information. An exposure device that exposes the photoconductor for each color image corresponding image (L in FIG. 7) and forms an electrostatic latent image corresponding to each color image on the photoconductor; A developing device 61 that develops using color toner (black toner, yellow toner, magenta toner, and cyan toner) to form a toner image with each color toner, and the toner image is an intermediate transfer member. The image forming apparatus includes a transfer charger 62 for transferring the image onto 0, a photoconductor cleaning device 63, and a static eliminator 64, and each monochrome image (black image, yellow image, magenta) based on the image information of each color. Image and cyan image) can be formed. The black image, the yellow image, the magenta image, and the cyan image formed in this way are formed on the black photoconductor 10K on the intermediate transfer member 50 that is rotationally moved by the support rollers 14, 15, and 16, respectively. The black image, the yellow image formed on the yellow photoconductor 10Y, the magenta image formed on the magenta photoconductor 10M, and the cyan image formed on the cyan photoconductor 10C are sequentially transferred (primary transfer). Is done. Then, the black image, the yellow image, the magenta image, and the cyan image are superimposed on the intermediate transfer member 50 to form a composite color image (color transfer image).

  On the other hand, in the paper feed table 200, one of the paper feed rollers 142 is selectively rotated to feed out a sheet (recording paper) from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143. Each sheet is separated and sent to the paper feed path 146, transported by the transport roller 147, guided to the paper feed path 148 in the copying machine main body 150, and abutted against the registration roller 49 and stopped. Alternatively, the sheet feed roller 142 is rotated to feed out sheets (recording paper) on the manual feed tray 54, separated one by one by the separation roller 52, put into the manual feed path 53, and abutted against the registration roller 49 and stopped. . The registration roller 49 is generally used while being grounded, but may be used in a state where a bias is applied to remove paper dust from the sheet. Then, the registration roller 49 is rotated in synchronization with the synthesized color image (color transfer image) synthesized on the intermediate transfer member 50, and a sheet (recording paper) is interposed between the intermediate transfer member 50 and the secondary transfer device 22. The secondary color transfer device 22 transfers the composite color image (color transfer image) onto the sheet (recording paper), thereby transferring the color image onto the sheet (recording paper). Is formed. The residual toner on the intermediate transfer member 50 after image transfer is cleaned by the intermediate transfer member cleaning device 17.

  The sheet (recording paper) on which the color image has been transferred is conveyed by the secondary transfer device 22 and sent to the fixing device 25, where the combined color image (color) is generated by heat and pressure. (Transfer image) is fixed on the sheet (recording paper). Thereafter, the sheet (recording paper) is switched by the switching claw 55 and discharged by the discharge roller 56 and stacked on the discharge tray 57, or switched by the switching claw 55 and reversed by the sheet reversing device 28 and transferred again. After being guided to the position and recording an image on the back surface, the image is discharged by the discharge roller 56 and stacked on the discharge tray 57.

  In the image forming apparatus and the image forming method of the present invention, in a scorotron charger type image forming apparatus on which a highly durable electrophotographic photosensitive member having a crosslinked surface layer on the outermost surface is mounted, It is possible to effectively suppress the occurrence of image density unevenness at the site immediately below the scorotron charger, and to form a clear high-quality image.

(Process cartridge)
The process cartridge of the present invention can develop an electrophotographic photosensitive member, a charger for uniformly charging the surface of the electrophotographic photosensitive member, and an electrostatic latent image formed on the electrophotographic photosensitive member using toner. Development means for forming a visual image, and further having other means such as a charger, an exposure device, a development means, a transfer means, a cleaning means, a static elimination means, which are appropriately selected as necessary. Become.
As the electrophotographic photosensitive member, a support and a support having at least a charge generation layer, a charge transport layer, and a crosslinked surface layer in this order on the support are used, and the same as the image forming apparatus described above is used. be able to.
The charger is a scorotron charger having a wire, a shield, and a grid, and the grid in the scorotron charger is coated with a polycondensate of organic titanate.
The developing means includes at least a developer container that contains toner or developer, and a developer carrier that carries and transports the toner or developer contained in the developer container. Furthermore, a layer thickness regulating member for regulating the thickness of the toner layer to be carried may be provided.
The process cartridge of the present invention can be detachably provided in various electrophotographic apparatuses, facsimiles, and printers, and is preferably provided detachably in the above-described image forming apparatus of the present invention.

Here, for example, as shown in FIG. 8, the process cartridge includes a photoreceptor 101, and further includes a charger 102, a developing unit 104, a cleaning unit 107, and a transfer unit 108, and further, if necessary. It has other members. In FIG. 8, reference numeral 103 denotes exposure light from the exposure device, and 105 denotes a recording medium.
As the photoreceptor 101, the same one as an image forming apparatus described later can be used. An arbitrary charging member is used as the charger 102.
Next, the image forming process using the process cartridge shown in FIG. 8 will be described. The photosensitive member 101 is charged on the surface by charging by the charging unit 102 and exposure 103 by the exposure unit (not shown) while rotating in the direction of the arrow. An electrostatic latent image corresponding to the exposure image is formed. The electrostatic latent image is developed with toner by the developing unit 104, and the toner development is transferred to the recording medium 105 by the transfer unit 108 and printed out. Next, the surface of the photoconductor after the image transfer is cleaned by the cleaning unit 107 and further neutralized by a neutralizing unit (not shown), and the above operation is repeated again.

  As an image forming apparatus of the present invention, the electrophotographic photosensitive member and components such as a developing unit and a cleaning unit are integrally combined as a process cartridge, and this unit is configured to be detachable from the apparatus main body. May be. In addition, at least one of a charger, an image exposure device, a developing device, a transfer or separation device, and a cleaning device is integrally supported together with the electrophotographic photosensitive member to form a process cartridge, and is detachable from the apparatus main unit. In addition, it may be configured to be detachable using guide means such as a rail of the apparatus main body.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following examples, the photoconductors and scorotron chargers that were prepared were intentionally deteriorated by applying a load in advance in order to simplify the evaluation.

Example 1
<Production of electrophotographic photoreceptor>
An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition are sequentially applied onto an aluminum drum having a thickness of 0.8 mm, a length of 340 mm, and an outer diameter of 100 mm, and dried. As a result, an undercoat layer having a thickness of 3.5 μm, a charge generation layer having a thickness of 0.2 μm, and a charge transport layer having a thickness of 23 μm were formed.
The resulting charge transport layer was sprayed with a cross-linked surface layer coating solution having the following composition, and this aluminum drum was then UV cured while rotating the drum at a distance of 120 mm from the UV curing lamp. The UV illuminating lamp illuminance at this position was 600 mW / cm ² (UV integrated light meter UIT-150, measured by Ushio Corporation). The drum rotation speed was 25 rpm. When performing UV curing, a rod-shaped metal block was included in an aluminum drum. In UV curing, exposure was performed for 4 minutes in total by repeating exposure for 30 seconds and rest for 120 seconds. After UV curing, it was dried by heating at 130 ° C. for 30 minutes. Thus, an electrophotographic photosensitive member having a crosslinked surface layer having a thickness of 8 μm was produced.

-Composition of undercoat layer coating solution-
・ Alkyd resin solution (Beckolite M6401-50, manufactured by Dainippon Ink and Chemicals, Inc.) ... 12 parts by mass Melamine resin solution (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals, Inc.) -8 parts by mass-Titanium oxide (CR-EL, manufactured by Ishihara Sangyo Co., Ltd.) ... 40 parts by mass-Methyl ethyl ketone ... 200 parts by mass

-Composition of coating solution for charge generation layer-
・ Titanyl phthalocyanine (manufactured by Ricoh Co., Ltd.): 20 parts by mass • Polyvinyl alcohol resin (ESREC B BX-1, manufactured by Sekisui Chemical Co., Ltd.): 10 parts by mass • Methyl ethyl ketone: 100 parts by mass

-Composition of coating solution for charge transport layer-
Polycarbonate resin (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.) 10 parts by mass Low molecular charge transport material represented by the following structural formula: 10 parts by mass
-Tetrahydrofuran ... 79 parts by mass-1% by mass silicone oil (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.) tetrahydrofuran solution ... 1 part by mass

-Composition of the cross-linked surface layer coating solution-
-Crosslinked charge transport material represented by the following structural formula: 47.5 parts by mass
Trimethylolpropane triacrylate (KAYARAD TMPTA, Nippon Kayaku Co., Ltd.) 47.5 parts by mass A mixture of acrylic group-containing polyester-modified polydimethylsiloxane and propoxy-modified-2-neopentylglycol diacrylate (BYK-UV3570) 0.1 mass part 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, Ciba Specialty Chemicals) 5 mass parts Tetrahydrofuran 566 mass parts

<Pretreatment of electrophotographic photoreceptor>
After the electrophotographic photosensitive member produced as described above is used for mounting, it is mounted on an image forming apparatus (Imagio Neo 1050Pro, manufactured by Ricoh Co., Ltd.) and 600 in a room temperature and normal humidity environment of 25 ° C. and 55% RH. A time free run test was conducted. The cleaning means and the transfer means were removed, and the discharge products on the surface of the photoreceptor were wiped off once a day.

<Pretreatment of Scorotron charger>
The scorotron charger grid attached to the image forming apparatus is spray-coated with a 10% by mass n-hexane solution of organic titanate [tetra-n-butoxytitanium (B-1, manufactured by Nippon Soda Co., Ltd.)]. Then, after drying with the finger touch, baking was performed at 400 ° C. for 5 minutes, and drying at room temperature for 24 hours was attached to a scorotron charger. The thickness of the coating was 0.5 μm.
The Scorotron charger continuously applied a 1.5 mA current to the charge wire using an external power source. At the same time, -800 V was applied to the grid, and corona discharge was performed for 24 hours. The test was performed in a low-temperature and low-humidity environment at 10 ° C. and 15% RH.

The electrophotographic photosensitive member and scorotron charger prepared as described above were mounted on an image forming apparatus (Imagio Neo 1050Pro, manufactured by Ricoh Co., Ltd.).
This image forming apparatus is placed in a test room of a low temperature and low humidity environment of 10 ° C. and 15% RH, and 10,000 copies of text and graphic image patterns having a pixel density of 600 dpi × 600 dpi and an image density of 6% are continuous. (My Paper A4 size, manufactured by NBS Ricoh Co., Ltd.). All consumables such as toner and replacement parts were genuine and used new ones.
After the printout was completed, the image forming apparatus was turned off, and the apparatus was allowed to stand for 10 hours in a low temperature and low humidity environment of 10 ° C. and 15% RH, and then a halftone image was output. As a result, a uniform halftone image with almost no abnormality was obtained. It was 3 to 4 quality in the 5 rank evaluation with 5 being the best.

(Comparative Example 1)
In Example 1, a new scorotron charger was pretreated in the same manner as in Example 1 except that the organic titanate coating on the grid was omitted in the pretreatment of the scorotron charger. Mounted on an image forming apparatus.

The photoreceptor used in Example 1 was allowed to stand in a dark place in a room temperature environment and then mounted on the image forming apparatus. It was confirmed that even if a halftone image was output, a good quality image without any abnormality could be obtained.
Next, the same test as in Example 1 was performed, and finally a halftone image was output. As a result, an image density unevenness equal to the width of the scorotron charger occurred in the photosensitive member cycle. In the same 5-grade evaluation as in Example 1, the quality was rank 2. Even when 1,000 images were output under the low temperature and low humidity environment of 10 ° C. and 15% RH, the image density unevenness did not disappear. Further, even when the image was output after the image forming apparatus was turned off and allowed to stand for several hours, the image density unevenness did not disappear. However, when the halftone image was output after changing the installation environment of the image forming apparatus to a room temperature and humidity environment of 20 ° C. and 50% RH, the image density unevenness disappeared.

(Example 2)
In Example 1, except that the organic titanate coating on the grid was changed to di-i-propoxy bis (acetylacetonato) titanium (T-50, manufactured by Nippon Soda Co., Ltd.) in the pretreatment of the scorotron charger. The test was performed in the same manner as in Example 1. The thickness of the organic titanate sol-gel cured film was 0.5 μm.

  After the same test as in Comparative Example 1, the photoreceptor was allowed to stand in the same manner before being subjected to the test. Finally, when a halftone image was output, a uniform halftone image without any abnormality was obtained. In the five-level rank evaluation with 5 being the best, the quality was 4-5.

  The image forming apparatus, the image forming method, and the process cartridge of the present invention suppress unevenness in image density that occurs in a low-temperature and low-humidity environment and enjoy the inherent durability of the photoreceptor. Widely used in electrophotographic application fields such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making, as well as being used in scorotron charger type electrophotographic copying machines equipped with various electrophotographic photosensitive members. Can be used.

FIG. 1 is a schematic diagram illustrating the characteristics of an abnormal image in which image density unevenness has occurred. FIG. 2 is a schematic sectional view showing an example of the layer structure of the electrophotographic photosensitive member used in the present invention. FIG. 3 is a schematic sectional view showing an example of another layer structure of the electrophotographic photosensitive member used in the present invention. FIG. 4 is a schematic view showing an example of a scorotron charger used in the image forming apparatus of the present invention. FIG. 5 is a schematic cross-sectional view showing an example of the image forming apparatus of the present invention. FIG. 6 is a schematic explanatory view showing an example in which the image forming method of the present invention is implemented by the image forming apparatus (tandem color image forming apparatus) of the present invention. FIG. 7 is a partially enlarged schematic explanatory view of the image forming apparatus shown in FIG. FIG. 8 is a schematic view showing an example of the process cartridge of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photosensitive member 2 Charging means 3 Exposure means 4 Developing means 5 Transfer means 6 Exposure means before cleaning 7 Cleaning means 8 Static elimination means 9 Fixing means 10 Photosensitive body (photosensitive drum)
10K black photoconductor 10Y yellow photoconductor 10M magenta photoconductor 10C cyan photoconductor 14 support roller 15 support roller 16 support roller 17 intermediate transfer cleaning device 18 image forming means 20 charging roller 21 exposure device 22 secondary transfer device 23 Roller 24 Secondary transfer belt 25 Fixing device 26 Fixing belt 27 Pressure belt 28 Sheet reversing device 30 Exposure device 32 Contact glass 33 First traveling member 34 Second traveling member 35 Imaging lens 36 Reading sensor 40 Developing device 41 Developing belt 42K Developer container 42Y Developer container 42M Developer container 42C Developer container 43K Developer supply roller 43Y Developer supply roller 43M Developer supply roller 43C Developer supply roller 44K Developer roller 44Y Developer roller 44M Developer Roller 44C Developing roller 45K Black developing unit 45Y Yellow developing unit 45M Magenta developing unit 45C Cyan developing unit 49 Registration roller 50 Intermediate transfer member 51 Roller 52 Separating roller 53 Manual feed path 54 Manual feed tray 55 Switching claw 56 Discharge roller 57 discharge tray 58 corona charger 60 cleaning device 61 developing device 62 transfer charger 63 photoconductor cleaning device 64 static eliminator 70 static elimination lamp 71 cleaning blade 72 support member 80 transfer roller 90 cleaning device 95 transfer paper 100 image forming apparatus 101 photoconductor DESCRIPTION OF SYMBOLS 102 Charging device 103 Exposure 104 Developing means 105 Recording medium 107 Cleaning means 108 Transfer means 120 Tandem type developing device 130 Document table 142 Feed roller 143 Paper bank 14 Paper feeding cassette 145 Separating roller 146 Feeding path 147 Conveying roller 148 Feeding path 150 Copying machine body 200 Feeding table 221 Support 224 Undercoat layer 225 Charge generation layer 226 Charge transport layer 228 Crosslinked surface layer 231 Shield 233 Grid 234 Wire 235 Photoconductor 300 Scanner 310 Tray 311 Recording medium (copy paper)
312 Paper discharge tray 313 Printed material 331 Electrophotographic photosensitive member 371 Cleaning blade 400 Automatic document feeder (ADF)

Claims (7)

Electrostatic latent image formation having an electrophotographic photosensitive member, a charger for uniformly charging the surface of the photosensitive member, and an exposure unit for exposing the surface of the photosensitive member charged by the charger to form an electrostatic latent image Development means for developing the electrostatic latent image with toner to form a visible image, transfer means for transferring the visible image to a recording medium, and fixing the transfer image transferred to the recording medium At least fixing means for causing
The electrophotographic photoreceptor has a support, and at least a charge generation layer, a charge transport layer, and a crosslinked surface layer in this order on the support,
An image forming apparatus, wherein the charger is a scorotron charger having a wire, a shield, and a grid, and the grid in the scorotron charger is coated with a polycondensate of an organic titanate.   The image forming apparatus according to claim 1, wherein the organic titanate is di-i-propoxy bis (acetylacetonato) titanium.   The cross-linked surface layer contains a cured product of a radically polymerizable compound having three or more functional groups having no charge transporting structure and a radically polymerizable compound having a monofunctional charge transporting structure. The image forming apparatus described in 1. The image forming apparatus according to claim 3, wherein the radical polymerizable compound having a monofunctional charge transporting structure is represented by the following structural formula (1).
However, in said structural formula (1), d, e, and f represent the integer of 0 or 1, respectively. R ¹ represents either a hydrogen atom or a methyl group. g and h represent the integer of 0-3. R ² and R ³ represent an alkyl group having 1 to 6 carbon atoms, and when g and h are 2 or more, the alkyl groups may be the same or different from each other. Z represents a single bond, a methylene group, an ethylene group, or a group represented by the following structural formula.
  The trifunctional or higher functional radical polymerizable compound having no charge transporting structure is at least one selected from trimethylolpropane triacrylate, caprolactone-modified dipentaerythritol hexaacrylate, and dipentaerythritol hexaacrylate. 5. The image forming apparatus according to any one of 4 above. An electrostatic latent image forming step using a charger that uniformly charges the surface of the electrophotographic photoreceptor, and an exposure device that exposes the surface of the photoreceptor charged by the charger to form an electrostatic latent image; At least a developing step of developing the latent image with toner to form a visible image, a transferring step of transferring the visible image to a recording medium, and a fixing step of fixing the transferred image transferred to the recording medium Comprising
The electrophotographic photoreceptor has a support, and at least a charge generation layer, a charge transport layer, and a crosslinked surface layer in this order on the support,
The image forming method, wherein the charger is a scorotron charger having a wire, a shield, and a grid, and the grid in the scorotron charger is coated with a polycondensate of organic titanate. An electrophotographic photosensitive member, a charger that uniformly charges the surface of the electrophotographic photosensitive member, and a developing unit that develops an electrostatic latent image formed on the electrophotographic photosensitive member with toner to form a visible image And at least
The electrophotographic photoreceptor has a support, and at least a charge generation layer, a charge transport layer, and a crosslinked surface layer in this order on the support,
A process cartridge, wherein the charger is a scorotron charger having a wire, a shield, and a grid, and the grid in the scorotron charger is coated with a polycondensate of an organic titanate.