JP4466420B2 - Method for producing organic photoreceptor - Google Patents

Description

  The present invention relates to an organic photoreceptor used in the field of copying machines and printers, a method for producing the organic photoreceptor, an image forming apparatus and a process cartridge using the organic photoreceptor.

  Organic photoconductors have great advantages such as wide selection of materials, excellent environmental suitability and low production costs compared to inorganic photoconductors such as selenium photoconductors and amorphous silicon photoconductors. In recent years, electrophotographic photoreceptors have become the mainstream in place of inorganic photoreceptors.

  On the other hand, in the image forming method based on the Carlson method, a charged, electrostatic latent image is formed on an organic photoreceptor, a toner image is formed, the toner image is transferred to a transfer paper, and this is fixed and a final image is formed. Is formed.

  A corona discharger is the best known charging member that has been used as a member of the charging means. The corona discharger has an advantage that stable charging can be performed. However, since a high voltage must be applied to the corona discharger, a large amount of ionized oxygen, ozone, moisture, nitric oxide compound, etc. is generated, which causes deterioration of the organic photoreceptor (hereinafter also referred to as a photoreceptor). Or have problems such as adversely affecting the human body.

  Therefore, in recent years, use of a contact charging method that does not use a corona discharger has been studied. Specifically, a voltage is applied to a magnetic brush or a conductive roller that is a charging member to bring it into contact with a photosensitive member that is a member to be charged, and the surface of the photosensitive member is charged to a predetermined potential. If such a contact charging method is used, the voltage can be lowered and the amount of ozone generated can be reduced as compared with a non-contact charging method using a corona discharger.

In the contact charging method, a direct current voltage or a direct current superimposed on an alternating current is applied to a charging member having a resistance of about 10 ² to 10 ¹⁰ Ω · cm, and the photosensitive member is pressed and brought into contact with the photosensitive member to give an electric charge. Is the method. Since this charging method is performed by discharging from the charging member to the member to be charged in accordance with Paschen's law, charging is started by applying a voltage equal to or higher than a certain threshold value. In this contact charging method, compared with the corona charging method, the voltage applied to the charging member is lowered, and the generation amount of ozone and nitrogen oxides is reduced.

  On the other hand, digitalization has progressed in recent image forming methods, and an image forming method using laser light as an exposure light source is often used for forming an electrostatic latent image on an organic photoreceptor.

  However, in the contact charging method with a charging roller or the like, an organic photoreceptor support processed to prevent interference fringes (hereinafter also referred to as moire) due to laser light exposure, that is, the surface is roughened by cutting or the like. When an aluminum support or the like is used, there is a problem that dielectric breakdown is likely to occur when the convex portion of the cut surface is contact charged. In addition, when the surface of the organic photoreceptor is repeatedly charged, cracks and contamination, etc. generated in the organic photoreceptor occur, and as a result, charges concentrate on the cracked and contaminated portions, resulting in dielectric breakdown, black spots, etc. Image defects are likely to occur, and image blur is likely to occur. In particular, these problems are likely to occur under severe conditions such as high temperature and high humidity and low temperature and low humidity.

  In order to solve such a problem, a technique of providing a thick intermediate layer in which resin fine particles are dispersed between a conductive substrate and a photosensitive layer is also known (Patent Document 1). However, with this technique, the residual potential tends to increase during long-term use of the photoreceptor, and good image formation is limited to the initial stage.

  Also known is a structure in which titanium oxide particles are dispersed in a resin as an intermediate layer between a conductive substrate and a photosensitive layer. For example, titanium oxide surface-treated with an amino group-containing coupling agent (Patent Document 2), titanium oxide surface-treated with an organosilicon compound (Patent Document 3), titanium oxide surface-treated with methylhydrogenpolysiloxane (Patent Document 3) Patent Document 4), an organic photoreceptor having an intermediate layer using dendritic titanium oxide (Patent Document 5) surface-treated with a metal oxide or an organic compound has been proposed.

  These titanium oxide-containing intermediate layers have excellent blocking properties that effectively prevent free carriers from entering the conductive support, and have the property that the residual potential does not increase easily even if the film thickness is increased. ing.

However, the intermediate layer coating solution in which these titanium oxides and the like are dispersed is easily affected by the binder and organic solvent used, and the dispersibility and coating property are easily affected. The thick intermediate layer is uniformly coated using a single organic solvent. It is difficult to apply, and uneven coating occurs in the intermediate layer after coating and drying, and not only the above-mentioned insulation breakdown and black spots cannot be sufficiently prevented, but also the problem that image unevenness is likely to occur in halftone images. is doing.
JP 2004-198734 A JP-A-9-96916 JP 9-258469 A JP-A-8-328283 JP-A-11-344826

An object of the present invention is to solve the above-mentioned problems of an organic photoreceptor used in a contact charging type image forming apparatus, and more specifically, has an intermediate layer containing inorganic particles such as conventional titanium oxide. Solves the above-mentioned problems of organic photoreceptors, can form a uniform and thick intermediate layer, prevents image defects such as dielectric breakdown and black spots, and stabilizes good electrophotographic images over the long term it is to provide a manufacturing how the organophotoreceptors can to be obtained.

  As a result of repeated investigations on the above problems of organophotoreceptors, it is important to uniformly coat a thick intermediate layer containing inorganic particles such as titanium oxide on the conductive support of the organophotoreceptor. As a result, the present invention has been achieved.

That is, in order to apply an intermediate layer containing inorganic particles such as titanium oxide uniformly in a thick film to prevent leakage resistance such as dielectric breakdown and to obtain a good electrophotographic image, a solubility parameter (in the present invention The present invention has been completed by finding that it is effective to form an intermediate layer using an intermediate layer coating solution using a mixed solvent of at least two kinds of SP values having a specific relationship. That is, the present invention is achieved by having the following configuration.
(Claim 1)
Between the electroconductive support and the photosensitive layer, in the manufacturing method of the organic photoreceptor to form an intermediate layer by coating an intermediate layer coating solution containing at least inorganic particles and a binder resin and an organic solvent, wherein the conductive support is An aluminum substrate having a ten-point average roughness Rz of 0.3 to 2.5 μm, the binder resin is an alcohol-soluble polyamide, and the organic solvent is at least two kinds of mixed solvents. Tetrahydrofuran, ethyl acetate and methyl ethyl ketone having a solubility parameter value (SP value) of 2.0 to 4.0 lower than that of the main solvent and a boiling point lower than that of the main solvent with respect to the main solvent of ethanol or n-propyl alcohol occupying a large amount selected sub solvent containing 10 to 40% by weight based on the total solvent mixture, and coating and drying the intermediate layer coating solution onto the conductive support from a, Method of manufacturing an organic photoreceptor thickness and forming an intermediate layer of 5 to 40 m.
(Claim 2)
The method for producing an organic photoreceptor according to claim 1, wherein the inorganic particles are a metal oxide.
(Claim 3)
3. The method for producing an organic photoreceptor according to claim 1, wherein the inorganic particles are subjected to a surface treatment.
(Claim 4)
The method for producing an organic photoreceptor according to claim 1, wherein the number average primary particle size of the inorganic particles is 3 nm or more and 200 nm or less.
(Claim 5)
The method for producing an organic photoreceptor according to claim 2, wherein the metal oxide is titanium oxide.
(Claim 6)
6. The method for producing an organic photoreceptor according to claim 1, wherein the secondary solvent is tetrahydrofuran.

  Hereinafter, the present invention will be described in detail.

The method for producing an organic photoreceptor of the present invention includes an organic photoreceptor in which an intermediate layer is formed by applying an intermediate layer coating solution containing at least inorganic particles, a binder resin, and an organic solvent between a conductive support and a photosensitive layer. In the production method, the conductive support is an aluminum substrate having a 10-point average roughness Rz of 0.3 to 2.5 μm, the binder resin is an alcohol-soluble polyamide, and the organic solvent is at least two or more kinds. The solubility parameter value (SP value) is 2.0 to 4.0 lower than the main solvent and has a boiling point with respect to the main solvent of ethanol or n-propyl alcohol occupying the maximum amount of the mixed solvent. lower than the main solvent of tetrahydrofuran, the Supporting solvent selected from among ethyl acetate and methyl ethyl ketone containing 10 to 40% by weight based on the total mixed solvent, the intermediate layer coating solution By coating and drying on a conductive support, thickness and forming an intermediate layer of 5 to 40 m.

  The organic photoconductor of the present invention has the above-described configuration, so that an organic photoconductor having a thick intermediate layer having a uniform film thickness can be produced, and charging means is charged by bringing a charging member into contact with the organic photoconductor It is possible to provide an organic photoreceptor that can prevent the occurrence of dielectric breakdown and can reproduce a halftone image clearly, which is likely to occur in an image forming apparatus having the above.

  Hereinafter, the structure of the organic photoreceptor of the present invention will be described.

  In the present invention, the intermediate layer refers to a layer provided between the conductive support and the photosensitive layer.

The inorganic particles used in the intermediate layer according to the present invention are titanium oxide (TiO ₂ ), zinc oxide (ZnO), tin oxide (SnO ₂ ), zirconium oxide, cerium oxide, iron oxide, aluminum oxide, tungsten oxide, bismuth oxide. Metal oxides such as silicon carbide and titanium carbide, metal carbides such as silicon carbide and titanium carbide, titanates such as strontium titanate, calcium titanate and barium titanate, carbonates such as calcium carbonate, metal nitrides such as aluminum nitride, Sulfates such as barium sulfate, copper sulfate, and zinc sulfate are also used.

  Among these inorganic particles, the inorganic particles preferably used in the present invention are preferably N-type semiconductor particles. The N-type semiconductive particle means a particle whose main charge carrier is an electron. That is, since the main charge carrier is an electron, the intermediate layer containing the N-type semiconductor particles in the insulating binder efficiently blocks hole injection from the conductive support, and the photosensitive layer. It has a property of exhibiting transportability with respect to electrons from.

As the N-type semiconductor particles, titanium oxide (TiO ₂ ) and zinc oxide (ZnO) are preferable, and titanium oxide is particularly preferably used.

  The inorganic particles are preferably fine particles having a number average primary particle size in the range of 3.0 to 200 nm. Particularly, 5 nm to 100 nm is preferable. The number average primary particle diameter is a measured value as the average diameter in the ferret direction by image analysis by magnifying fine particles 10,000 times by transmission electron microscope observation, randomly observing 100 particles as primary particles. Inorganic particles having a number average primary particle size of less than 3.0 nm are difficult to uniformly disperse in the intermediate layer binder, tend to form aggregated particles, and the aggregated particles serve as charge traps and easily generate transfer memory. On the other hand, inorganic particles having a number average primary particle size larger than 200 nm tend to make large irregularities on the surface of the intermediate layer, and dielectric breakdown and black spots are likely to occur through these large irregularities. In addition, inorganic particles having a number average primary particle size larger than 200 nm are likely to precipitate in the dispersion and easily generate aggregates.

  For example, in the case of titanium oxide, the number average primary particle size of inorganic particles is magnified 10,000 times by observation with a transmission electron microscope, and 100 particles are randomly observed as primary particles, and the number of ferret diameters is determined by image analysis. Measured as average diameter.

  The titanium oxide particles have anatase, rutile, brookite, and amorphous forms as crystal forms. Among them, the rutile form titanium oxide pigment or the anatase form titanium oxide pigment has a rectifying property of charge passing through the intermediate layer. In other words, the electron mobility is increased, the charging potential is stabilized, the residual potential is prevented from increasing, and a high-density dot image can be formed.

  The inorganic particles are preferably surface-treated with a polymer containing methylhydrogensiloxane units. The molecular weight of the polymer containing the methylhydrogensiloxane unit is 1000 to 20000, which has a high surface treatment effect. As a result, the rectifying property of the inorganic particles is improved, and by using an intermediate layer containing the inorganic particles, black The generation of spots is prevented, and it is effective in producing a high-density dot image.

The polymer containing a methylhydrogensiloxane unit is preferably a copolymer of a structural unit of-(HSi (CH ₃ ) O)-and a structural unit other than this (other siloxane unit). As other siloxane units, dimethylsiloxane units, methylethylsiloxane units, methylphenylsiloxane units, diethylsiloxane units, and the like are preferable, and dimethylsiloxane is particularly preferable. The proportion of methylhydrogensiloxane units in the copolymer is 10 to 99 mol%, preferably 20 to 90 mol%.

  The methylhydrogensiloxane copolymer may be any of a random copolymer, a block copolymer, a graft copolymer, etc., but a random copolymer and a block copolymer are preferred. In addition to methylhydrogensiloxane, the copolymerization component may be one component or two or more components.

  In addition, the inorganic particles may be surface-treated with a reactive organosilicon compound represented by the following formula.

(R) _n -Si- (X) _4-n
(In the above formula, Si represents a silicon atom, R represents an organic group in which carbon is directly bonded to the silicon atom, X represents a hydrolyzable group, and n represents an integer of 0 to 3).
In the organosilicon compound represented by the above formula, the organic group in which carbon is directly bonded to the silicon represented by R includes alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl and dodecyl, phenyl , Aryl groups such as tolyl, naphthyl and biphenyl, epoxy-containing groups such as γ-glycidoxypropyl, β- (3,4-epoxycyclohexyl) ethyl, γ-acryloxypropyl and γ-methacryloxypropyl ( (Meth) acryloyl group, γ-hydroxypropyl, hydroxyl group such as 2,3-dihydroxypropyloxypropyl, vinyl group such as vinyl and propenyl, mercapto group such as γ-mercaptopropyl, γ-aminopropyl, N-β Amino-containing groups such as (aminoethyl) -γ-aminopropyl, γ-chloropropyl, 1,1, - trifluoride Oro propyl, nonafluorohexyl, halogen-containing groups such as perfluorooctylethyl, other nitro, and cyano-substituted alkyl group. Examples of the hydrolyzable group for X include alkoxy groups such as methoxy and ethoxy, halogen groups, and acyloxy groups.

  Moreover, the organosilicon compound represented by the above formula may be used alone or in combination of two or more.

  Further, in the case of a specific compound of an organosilicon compound represented by the above formula and n is 2 or more, a plurality of R may be the same or different. Similarly, when n is 2 or less, the plurality of Xs may be the same or different. Moreover, when using 2 or more types of organosilicon compounds represented by the above formula, R and X may be the same or different between the respective compounds.

  The inorganic particles may be subjected to an inorganic surface treatment such as alumina or silica prior to the surface treatment of the methylhydrogensiloxane copolymer or the reactive organosilicon compound.

  Prior to the surface treatment of the N-type semiconductor particles, at least one kind of surface treatment selected from alumina, silica, and zirconia may be performed.

  The alumina treatment, silica treatment, and zirconia treatment are treatments for precipitating alumina, silica, or zirconia on the surface of anatase-type titanium oxide. Japanese products are also included.

  The treatment of alumina and silica may be performed simultaneously, but it is particularly preferable to perform the alumina treatment first and then the silica treatment. Further, the amount of treatment of alumina and silica when treating alumina and silica is preferably higher than that of alumina.

  The intermediate layer coating solution prepared for forming the intermediate layer according to the present invention is composed of a binder resin, a dispersion solvent and the like in addition to the inorganic particles such as the surface-treated titanium oxide.

  The ratio of the inorganic particles in the intermediate layer is preferably 1.0 to 2.0 times in terms of the volume ratio of the intermediate layer to the binder resin (when the volume of the binder resin is 1). By including such high-density inorganic particles in the intermediate layer, the rectification property of the intermediate layer is improved, and even if the film thickness is increased, the residual potential does not increase and transfer memory does not occur. Can be effectively prevented, and a good organic photoreceptor with small potential fluctuation can be formed. In addition, such an intermediate layer preferably uses 100 to 200 parts by volume of inorganic particles with respect to 100 parts by volume of the binder resin.

  On the other hand, the binder resin in which these particles are dispersed to form the layer structure of the intermediate layer is preferably a polyamide resin in order to obtain good dispersibility of the particles, but the polyamide resin shown below is particularly preferable.

  That is, the intermediate layer according to the present invention is preferably a polyamide resin having a heat of fusion of 0 to 40 J / g and a water absorption of 5% by mass or less. The heat of fusion is more preferably 0 to 30 J / g, and most preferably 0 to 20 J / g. On the other hand, when the water absorption rate exceeds 5% by mass, the moisture content in the intermediate layer increases, dielectric breakdown and black spots are likely to occur, and electrophotographic characteristics such as increased residual potential and fogging are also likely to deteriorate. . The water absorption is more preferably 4% by mass or less.

  The heat of fusion of the resin is measured by DSC (Differential Scanning Calorimetry). However, if the same measurement value as the DSC measurement value is obtained, the DSC measurement method is not particular. The heat of fusion is determined from the endothermic peak area when the DSC temperature rises.

  On the other hand, the water absorption rate of the resin is determined by mass change by the water immersion method or by the Karl Fischer method.

An alcohol-soluble polyamide resin is used as the binder resin for the intermediate layer according to the present invention . As the binder resin for the intermediate layer of the organic photoreceptor, a resin having excellent solvent solubility is required in order to form the intermediate layer with a uniform film thickness. As such an alcohol-soluble polyamide resin, a copolymerized polyamide resin or a methoxymethylated polyamide resin composed of a chemical structure with few carbon chains between amide bonds such as 6-nylon described above is known. This resin has a high water absorption rate, and the intermediate layer using such a polyamide tends to be highly environment-dependent. As a result, for example, charging characteristics and sensitivity under high temperature and high humidity and low temperature and low humidity are likely to change. Dielectric breakdown and black spots are also likely to occur.

  Alcohol-soluble polyamide resin improves the above-mentioned drawbacks and improves the disadvantages of conventional alcohol-soluble polyamide resins by giving the characteristics of heat of fusion 0-40 J / g and water absorption of 5% by mass or less. Even if the external environment changes or even if the organic photoreceptor is used continuously for a long time, a good electrophotographic image can be obtained.

  Hereinafter, the alcohol-soluble polyamide resin having a heat of fusion of 0 to 40 J / g and a water absorption of 5% by mass or less will be described.

  The alcohol-soluble polyamide resin is preferably a polyamide resin containing a repeating unit structure having 7 to 30 carbon atoms between amide bonds in an amount of 40 to 100 mol% of the entire repeating unit structure.

  Here, a repeating unit structure having 7 to 30 carbon atoms between amide bonds will be described. The repeating unit structure means an amide bond unit forming a polyamide resin. This is because a polyamide resin (type A) formed by condensation of a compound having a repeating unit structure having both an amino group and a carboxylic acid group, and a polyamide resin (type B) formed by condensation of a diamino compound and a dicarboxylic acid compound. ) In both examples.

  That is, the repeating unit structure of type A is represented by the general formula (2), and the carbon number contained in X is the carbon number of the amide bond unit in the repeating unit structure. On the other hand, the type B repeating unit structure is represented by the general formula (3), and the number of carbon atoms contained in Y and the number of carbon atoms contained in Z are the carbon number of the amide bond unit in the repeating unit structure.

In general formula (2), R ₁ is a hydrogen atom, a substituted or unsubstituted alkyl group, X is a substituted or unsubstituted alkylene group, a group containing a divalent cycloalkane, a divalent aromatic group, and these A mixed structure is shown, and l is a natural number.

In general formula (3), R ₂ and R ₃ are each hydrogen atom, a substituted or unsubstituted alkyl group, Y and Z are each substituted or unsubstituted alkylene group, a group containing a divalent cycloalkane, and a divalent group. And m and n are natural numbers.

  As described above, the repeating unit structure having 7 to 30 carbon atoms includes a substituted or unsubstituted alkylene group, a group containing a divalent cycloalkane, a divalent aromatic group, and a chemical structure having a mixed structure thereof. Among them, a chemical structure having a group containing a divalent cycloalkane is preferable.

  The polyamide resin has 7 to 30 carbon atoms between amide bonds in the repeating unit structure, preferably 9 to 25, more preferably 11 to 20. The proportion of the repeating unit structure having 7 to 30 carbon atoms between amide bonds in the entire repeating unit structure is 40 to 100 mol%, preferably 60 to 100 mol%, more preferably 80 to 100 mol%.

  When the carbon number is less than 7, the hygroscopicity of the polyamide resin is large, the electrophotographic characteristics, particularly the humidity dependency of the potential during repeated use is large, and image defects such as black spots are likely to occur. If it is larger than 30, the dissolution of the polyamide resin in the coating solvent becomes worse, and it is not suitable for forming a coating film of the intermediate layer.

  Further, when the ratio of the repeating unit structure having 7 to 30 carbon atoms between amide bonds to the entire repeating unit structure is smaller than 40 mol%, the above effect is reduced.

  Preferred polyamide resins include polyamides having a repeating unit structure represented by the following general formula (4).

In General Formula (4), Y ₁ is a group containing a divalent alkyl-substituted cycloalkane, Z ₁ is a methylene group, m is 1 to 3, and n is 3 to 20.

In the general formula (4), the group containing a divalent alkyl-substituted cycloalkane of Y ₁ preferably has the following chemical structure. That is, the polyamide resin in which Y ₁ has the following chemical structure has a remarkable effect of improving black spots.

In the above chemical structure, A represents a single bond and an alkylene group having 1 to 4 carbon atoms, R ₄ represents a substituent, represents an alkyl group, and p represents a natural number of 1 to 5. However, the plurality of R ₄ may be the same or different.

  Specific examples of the polyamide resin include the following examples.

  In the above specific examples, “%” in parentheses indicates the ratio (mol%) of the repeating unit structure having 7 or more carbon atoms between amide bonds in the repeating unit structure.

  Among the above specific examples, N-1 to N-4 polyamide resins having a repeating unit structure of the general formula (4) are particularly preferable.

  The molecular weight of the polyamide resin is preferably 5,000 to 80,000 in terms of number average molecular weight, and more preferably 10,000 to 60,000. When the number average molecular weight is 5,000 or less, the uniformity of the film thickness of the intermediate layer is deteriorated, and the effects of the present invention are not sufficiently exhibited. On the other hand, if it is larger than 80,000, the solvent solubility of the resin tends to be lowered, and an aggregated resin is likely to be generated in the intermediate layer, and image defects such as black spots are likely to occur.

  A part of the polyamide resin is already available on the market. For example, the polyamide resin is sold under the trade names such as Vestamelt X1010 and X4685 manufactured by Daicel Degussa Co., Ltd. and can be produced by a general synthesis method of polyamide. .

  In the present invention, in order to prepare a coating liquid in which the binder resin of the intermediate layer is dissolved and the inorganic particles are dispersed, at least two kinds of mixed solvents are used as the solvent of the intermediate layer, and the maximum amount of the mixed solvent is occupied. 10-40% by mass of an organic solvent whose solubility parameter value (SP value) is 2.0 to 4.0 lower than that of the main solvent and whose boiling point is lower than that of the main solvent relative to the main solvent. A mixed solvent is used. By using such a mixed solvent, an intermediate layer in which inorganic particles are uniformly dispersed can be applied to a uniform film thickness of 5 to 40 μm, and dielectric breakdown is likely to occur in an electrophotographic process such as contact charging. In addition to preventing uneven coating, a clear halftone image can be obtained.

In the present invention, the solubility parameter value is defined by Yuji Harasaki, “Basic Science of Coating”, pages 54-57, Tables 3-9 in 1986 (Tsubaki Shoten), “Evaporation energy and molar volume of atoms and atomic groups by Fedors” (25 C.) ”is a value defined by the method of calculating the solubility parameter value (SP) from the compound structural formula described in“. The solubility parameter is also referred to as a solubility parameter or a compatibility parameter, and is basically a ½ power of cohesive energy density, that is, (cohesive energy [cal / mol]) / (molecular volume [cm ^3]. / Mol]) is a value defined by the 1/2 power, and is a useful physical property value mainly used to predict the solubility of the polymer in various solvents. In addition to the above, the method for determining the solubility parameter includes a method for measuring solubility with a solvent, a method for measuring the swelling property of the solvent, a method for determining from the measurement of intrinsic viscosity, etc. The calculated value by Fedors is used.

In the mixed solvent according to the present invention, ethanol or n-propyl alcohol is used as the main solvent having the maximum mass . These solvents are excellent in solubility of alcohol-soluble polyamides. It is excellent in the coating property of the coating liquid. These solvents are 30 to 100% by mass, preferably 40 to 100% by mass, and more preferably 50 to 100% by mass in the total solvent.

A secondary solvent selected from tetrahydrofuran, ethyl acetate, and methyl ethyl ketone is used as a secondary solvent that can be used in combination with the primary solvent to obtain a preferable effect . One or more types of secondary solvents can be used. Further, the classification of the main solvent and the subsolvent is not absolute, and the above-exemplified main solvent may be the subsolvent, or the subsolvent may be the main solvent.

  That is, the mixed solvent according to the present invention uses at least one subsolvent whose melting point is lower than that of the main solvent and whose solubility parameter value (SP value) is 2.0 to 4.0 lower than that of the main solvent. It is made to contain 10-40 mass% with respect to a mixed solvent. By using such a mixed solvent, an intermediate layer containing inorganic particles can be applied thickly and uniformly, and an organic layer having an intermediate layer that prevents the occurrence of charge leakage such as dielectric breakdown without causing uneven coating. A photoreceptor can be produced.

  When the secondary solvent is less than 10% by mass, the viscosity of the intermediate layer coating solution is too high and unevenness in the intermediate layer is likely to occur. On the other hand, when the content is more than 40% by mass, the dispersibility of the inorganic particles is deteriorated, and the residual potential is likely to increase and dielectric breakdown is likely to occur. If the SP value of the secondary solvent is too high or too low, the dispersed bonds of the inorganic particles are deteriorated, unevenness in the step is likely to occur, and the residual potential is likely to increase or cause dielectric breakdown.

  Moreover, the mixed solvent concerning this invention can use a 3rd solvent other than the said main solvent and a subsolvent. Here, the third solvent means a third solvent that does not satisfy the relationship between the main solvent and the sub-solvent, and the solvents exemplified above may be used as long as these relationships are not satisfied. These solvents may be used. One or more types of the third solvent may be used. However, the SP value of the third solvent is also preferably a solvent close to the SP value of the main solvent, and the difference from the SP value of the main solvent is preferably within 4.0 in absolute value.

  The film thickness of the intermediate layer according to the present invention is preferably 5 to 40 μm. If the thickness of the intermediate layer is less than 5 μm, dielectric breakdown and black spots are likely to occur, and if it exceeds 40 μm, the residual potential is likely to increase and transfer memory is likely to occur, and the sharpness is likely to deteriorate. As for the film thickness of an intermediate | middle layer, 6-25 micrometers is more preferable.

The intermediate layer according to the present invention is preferably substantially an insulating layer. Here, the insulating layer has a volume resistance of 1 × 10 ⁸ or more. The volume resistance of the intermediate layer and the protective layer according to the present invention is preferably 1 × 10 ⁸ to 10 ¹⁵ Ω · cm, more preferably 1 × 10 ⁹ to 10 ¹⁴ Ω · cm, and still more preferably 2 × 10 ⁹ to 1 × 10 ¹³ Ω · cm. The volume resistance can be measured as follows.

  Measurement conditions: According to JIS: C2318-1975.

Measuring instrument: Hiresta IP manufactured by Mitsubishi Yuka
Measurement conditions: Measurement probe HRS
Applied voltage: 500V
Measurement environment: 30 ± 2 ℃, 80 ± 5RH%
If the volume resistance is less than 1 × 10 ⁸ , the charge blocking property of the intermediate layer decreases, the occurrence of black spots increases, the potential holding property of the organic photoreceptor deteriorates, and good image quality cannot be obtained. On the other hand, if it is greater than 10 ¹⁵ Ω · cm, the residual potential tends to increase in repeated image formation, and good image quality cannot be obtained.

  Next, the conductive support according to the present invention will be described.

  The conductive support used for the photosensitive member may be either a sheet or a cylinder, but a cylindrical conductive support is more preferable for designing an image forming apparatus compactly.

  Cylindrical conductive support means a cylindrical support necessary for forming an endless image by rotating. Conductivity is within a range of 0.1 mm or less in straightness and 0.1 mm or less in deflection. A support is preferred. Exceeding the range of straightness and shake makes it difficult to form a good image.

As the conductive material, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide or the like, or a paper / plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ωcm or less at room temperature. The conductive support according to the present invention is most preferably an aluminum support. As the aluminum support, one in which components such as manganese, zinc, magnesium and the like are mixed in addition to the main component aluminum is also used.

In the present invention, the ten-point surface roughness Rz of the conductive support (Rz meaning the value of the reference length 0.25mm according to JISB0601-1982) roughening of 0.3~2.5μm a. Even if the conductive support is roughened within this range, it is possible to prevent leakage resistance such as dielectric breakdown by applying a thick intermediate layer, and when a laser light source is used as an exposure light source, Thus, the generation of moire can be prevented.

  Next, the layer structure of the organic photoreceptor having the above intermediate layer and conductive support will be described.

  The organic photoconductor of the present invention means an electrophotographic photoconductor constituted by giving an organic compound at least one of a charge generation function and a charge transport function indispensable for the constitution of the electrophotographic photoconductor. It contains all known organic electrophotographic photoreceptors such as a photoreceptor composed of an organic charge generating material or an organic charge transport material, a photoreceptor composed of a polymer complex with a charge generating function and a charge transport function.

  The constitution of the organic photoreceptor used in the present invention is described below.

  As the conductive support according to the present invention, the conductive support described above is used.

Conductive Support Intermediate Layer In the present invention, the intermediate layer described above is provided between the conductive support and the photosensitive layer.

Photosensitive layer The photosensitive layer configuration of the photoconductor according to the present invention may be a single-layer photosensitive layer configuration in which a charge generation function and a charge transport function are provided on one layer on the intermediate layer. It is preferable that the function is separated into a charge generation layer (CGL) and a charge transport layer (CTL). By adopting a configuration in which the functions are separated, an increase in the residual potential due to repeated use can be controlled small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negatively charged photoconductor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer and a charge transport layer (CTL) is formed thereon. In the positively charged photoconductor, the order of the layer configuration is the reverse of that in the negatively charged photoconductor. The most preferred photosensitive layer structure of the present invention is a negatively charged photoreceptor structure having the function separation structure.

  The structure of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below.

Charge generation layer The charge generation layer contains a charge generation material (CGM). Other substances may contain a binder resin and other additives as necessary.

  A known charge generation material (CGM) can be used as the charge generation material (CGM). For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azulenium pigment, or the like can be used. Among these, CGM which can minimize the increase in residual potential due to repeated use has a crystal structure capable of taking a stable aggregate structure among a plurality of molecules, specifically, a phthalocyanine pigment having a specific crystal structure, CGM of a perylene pigment is mentioned. For example, titanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to Cu—Kα rays, titanyl phthalocyanine having a remarkable diffraction peak at 7.5 ° and 28.7 ° of the same 2θ, and 12.2 of the same 2θ. CGM such as benzimidazole perylene having a maximum peak at 4 has almost no deterioration due to repeated use, and the residual potential can be increased and decreased.

  When a binder is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin, and the like. Can be mentioned. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 μm to 1 μm. If the thickness is less than 0.01 μm, sufficient sensitivity characteristics cannot be obtained, and the residual potential tends to increase. On the other hand, if it exceeds 1 μm, dielectric breakdown and black spots are likely to occur.

On the other hand, the structure of the charge transport layer can be obtained using a known structure. It is necessary to select the charge transport material and binder appropriately to form the charge transport layer.

  As the charge transport material (CTM), for example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used in combination. These charge transport materials are usually dissolved in a suitable binder resin to form a layer.

  Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, and polycarbonate. Resin, silicone resin, melamine resin, and copolymer resin containing two or more of repeating unit structures of these resins. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used.

  Most preferred as a binder for these CTLs is a polycarbonate resin. The polycarbonate resin is most preferable in improving the dispersibility and electrophotographic characteristics of CTM. The ratio of the binder resin to the charge transport material is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  The charge transport layer preferably contains an antioxidant. Typical examples of the antioxidants are those that prevent the action of oxygen under conditions of light, heat, discharge, etc. on auto-oxidizing substances present in the organic photoreceptor or on the surface of the organic photoreceptor, It is a substance that has the property of inhibiting.

  The charge transport layer according to the present invention is a charge transport layer having a thickness of 10 to 30 μm. When the film thickness is less than 10 μm, dielectric breakdown, black spots, etc. are likely to occur, and when it exceeds 30 μm, the image is easily blurred and sharpness is liable to deteriorate.

  In the above, the most preferable layer structure of the photoreceptor of the present invention is exemplified, but in the present invention, a photoreceptor layer structure other than the above may be used. That is, the charge transport layer may be composed of two layers, or a protective layer may be provided on the charge transport layer.

  As a solvent or dispersion medium used for layer formation such as a charge generation layer and a charge transport layer, n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methyl ethyl ketone, Methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane, Tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve, etc. And the like. Although this invention is not limited to these, Dichloromethane, 1, 2- dichloroethane, methyl ethyl ketone, etc. are used preferably. These solvents may be used alone or as a mixed solvent of two or more.

  Further, the coating solution for each layer is preferably filtered with a metal filter, a membrane filter or the like in order to remove foreign matters and aggregates in the coating solution before entering the coating step. For example, it is preferable to select a pleat type (HDC), a depth type (profile), a semi-depth type (profile star), etc., manufactured by Nippon Pole Co., Ltd. according to the characteristics of the coating solution and perform filtration.

  Next, as a coating processing method for manufacturing the organic photoreceptor, a coating processing method such as dip coating, spray coating, circular amount regulation type coating or the like is used. It is most preferable to use the circular amount regulation type coating method for the protective layer. The circular amount regulation type coating is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.

  Next, an image forming apparatus using the contact charging method according to the present invention will be described.

  FIG. 1 is a schematic cross-sectional view of an image forming apparatus 1 using a contact charging method according to the present invention. The image forming apparatus 1 includes a photosensitive member cartridge 2, a developing cartridge (developing unit) 3, an exposure unit (exposure unit) 4 that emits while deflecting a laser beam modulated based on an image signal from the outside, and recording paper. A paper feeding device (paper feeding means) 5, a transfer roller (transfer means) 6, a fixing device (fixing means) 7 and a paper discharge tray 8 are disposed.

  The photoreceptor cartridge 2 includes a photoreceptor 21 formed by forming a thin film layer of an organic photoconductive material on the outer peripheral surface of a cylindrical body, a charging brush (charging means) 22 and the like. The developing cartridge 3 includes a developing sleeve (not shown), a stirring roller, and a toner tank in which toner and a carrier are accommodated. A developing bias is applied to the developing sleeve from a developing power source (not shown). Both cartridges are closed when inserted into the image forming apparatus 1 in order to prevent problems caused by mechanical contact when the cartridge is attached to or detached from the image forming apparatus 1, and are removed from the image forming apparatus 1. A protective cover (not shown) that is sometimes opened is provided.

  Since the image forming process is well known, only a brief description will be given below. First, the surface of the photoreceptor 21 is uniformly charged with a predetermined voltage by the charging brush 22. The exposure device 4 generates a modulated laser beam (indicated by a broken arrow in the figure), deflects the laser beam by a polygon mirror (not shown), deflects and scans the surface of the photosensitive member 21, and applies it to the charged surface. The electrostatic latent images corresponding to the image information are sequentially formed. The toner in the toner tank is stirred by a stirring roller and then supplied onto the developing sleeve to form a toner image corresponding to the electrostatic latent image at a portion facing the photoreceptor 21. At the same time, residual toner existing in a portion (non-image portion) that has not been exposed on the surface of the photoconductor 21 is developed using the potential difference between the developing bias voltage applied to the developing sleeve and the surface potential of the photoconductor 21. The cartridge is recovered by electrostatic force. On the other hand, the toner image is electrostatically transferred onto the recording paper by the transfer roller 6 disposed facing the photoconductor 21. Note that the recording paper is conveyed from the paper feeding device 5 along a conveyance path indicated by a solid line arrow in the drawing. Next, the recording paper is conveyed to the fixing device 7 where the unfixed toner image is heat-fixed on the recording paper. Finally, the recording paper on which a desired image is formed is discharged from the paper discharge tray 8. By repeating the above-described series of processes, a large amount of original can be duplicated at high speed.

  The charging brush mechanically agitates the residual toner sent to the contact portion with the photoconductor by the rotation of the photoconductor and diffuses it on the surface of the photoconductor until it becomes unreadable. The charging brush electrostatically adsorbs and collects residual toner having the opposite polarity (reverse polarity) to the charging polarity of the photoconductor, and charges it to the same polarity (regular polarity) as the charging polarity of the photoconductor. Discharge onto the surface of the photoreceptor.

  FIG. 2 is a schematic cross-sectional view of a photosensitive cartridge 2 that is detachable from the image forming apparatus 1. The photosensitive member cartridge 2 includes a protective member 28 with a protective cover, a photosensitive member 21 as an image carrier, a charging brush 22 disposed around the photosensitive member 21, and a power source for applying a predetermined voltage to the charging brush 22. The connecting member 23, the pre-charge film 24, the charge leveling members (sponge-like charging members) 25 and 26, and the power source connecting member 27 are accommodated.

  The photosensitive member 21 is rotated in the direction of the arrow in the drawing by a driving device (not shown). The charging brush 22 is obtained by implanting conductive yarn made of hairy fibers on a brush support. The charging brush 22 is in contact with the surface of the photosensitive member 21 and is rotated in the same direction as the rotational direction of the photosensitive member 21 in the direction of the arrow in the drawing, that is, in the contact portion with the photosensitive member 21 by a driving device (not shown). . At the time of image formation, a voltage is applied to the charging brush 22 from a charging power source (not shown), whereby the surface of the photoreceptor 21 is uniformly charged to a predetermined polarity. On the other hand, at the time of non-image formation, a voltage having a polarity opposite to that at the time of image formation is applied to the charging brush 22 from the charging power source. The charging polarity of the toner is the same as the polarity of the charging voltage at the time of image formation. Therefore, at the time of non-image formation, the toner accumulated in the charging brush 22 can be ejected onto the photoreceptor 21 by electrostatic repulsion.

  The development pre-charge film 24 and the charge leveling members 25 and 26 are arranged for the purpose of compensating for uneven charging by the charging brush 22.

  The image forming apparatus is a monochrome laser printer, but can be similarly applied to a color laser printer or a copy. The exposure light source may also be a light source other than a laser, such as an LED light source.

  The image forming apparatus is a cleanerless image forming apparatus, but may be an image forming apparatus provided with a dedicated cleaning device (cleaning means) for collecting residual toner. That is, the present invention can also be applied to an image forming apparatus that is not a cleanerless type. The organic photoreceptor of the present invention may be used in a charger (corona charger or the like) in which the charging means is non-contact.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. In the following text, “part” means part by mass.

  A photoreceptor used for evaluation was produced as follows.

Preparation of photoreceptor 1 Intermediate layer 1
The following intermediate layer coating solution was applied by a dip coating method on a washed cylindrical aluminum substrate (processed to 10-point surface roughness Rz: 0.81 μm as defined in JISB-0601 by cutting) at 120 ° C. for 30 minutes. It dried and formed the intermediate | middle layer 1 with a dry film thickness of 5.0 micrometers.

(Preparation of intermediate layer coating solution)
Binder resin: (Exemplary polyamide N-1) 1 part (1.00 volume part)
Inorganic particles: Rutile-type titanium oxide A1 (primary particle size 35 nm; copolymer A (molar ratio 1: 1) of methyl hydrogen siloxane and dimethyl hydrogen siloxane, surface of 5% by mass of the total mass of titanium oxide 5.6 parts (1.60 parts by volume)
Solvent: ethanol / n-isopropyl alcohol / THF (= 45/20/35)
10 parts The above components were mixed and dispersed by a batch method using a sand mill disperser for 10 hours to prepare an intermediate layer coating solution.

Charge generation layer The following components were mixed and dispersed using a sand mill disperser to prepare a charge generation layer coating solution. This coating solution was applied by a dip coating method to form a charge generation layer having a dry film thickness of 0.3 μm on the intermediate layer.

Y-form oxytitanyl phthalocyanine (X-ray diffraction spectrum by Cu-Kα characteristic X-ray, maximum peak angle is 27.3 at 2θ) 20 parts Polyvinyl butyral (# 6000-C, manufactured by Denki Kagaku Kogyo) 10 parts Acetic acid t -Butyl 700 parts 4-Methoxy-4-methyl-2-pentanone 300 parts Charge transport layer The following components were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method to form a charge transport layer having a dry film thickness of 24 μm.

Charge transport material (4-methoxy-4 ′-(4-methyl-α-phenylstyryl) triphenylamine) 75 parts Polycarbonate resin “Iupilon-Z300” (Mitsubishi Gas Chemical Co., Ltd.) 100 parts Antioxidant (Compound A below) ) 2 parts tetrahydrofuran / toluene (volume ratio 7/3) 750 parts

Production of Photoreceptors 2 to 17 Photoreceptor 1 was produced in the same manner as production of Photoreceptor 1 except that the inorganic particles, the solvent, and the intermediate layer thickness in the intermediate layer coating solution were changed as shown in Table 1. Body 2-17 was produced.

In Table 1,
The solvent E ethanol THF tetrahydrofuran EA ethyl acetate n-Pr is n- propyl alcohol A is acetone M methanol D is 1,3-dioxolane MEK is methyl ethyl ketone inorganic particles R-TiO _2: rutile type titanium oxide A-TiO ₂ : Anatase type titanium oxide ZnO: Zinc oxide Al ₂ O ₃ : Alumina Surface treatment of inorganic particles A is a copolymer of methylhydrogensiloxane and dimethylsiloxane (molar ratio 1: 1)
B is a copolymer of methylhydrogensiloxane and methylethylsiloxane (molar ratio 1: 1)
C is methyl hydrogen polysiloxane D is primary treatment: silica / alumina, secondary treatment methyltrimethoxysilane Evaluation Evaluation of intermediate layer coating property The coating property of the intermediate layer of each photoreceptor after the intermediate layer coating and drying is visually observed. The coating property of the intermediate layer was observed. The result was described in the column of intermediate layer applicability.

○: The intermediate layer is uniformly formed on the entire surface (good)
Δ: Step unevenness is partially generated in the intermediate layer. (Suspect)
X: Step unevenness occurs on the entire surface of the intermediate layer. (There are practical problems)
Image Evaluation The photoconductors 1 to 17 obtained as described above are basically PAGEPRO1250E having the structure shown in FIGS. 1 and 2 (manufactured by Konica Minolta Business Technologies, Inc .: A4 paper 16 sheets / minute printer: contact) Each was mounted on an electrification and cleanerless process), and evaluated in different environments under high temperature and high humidity (30 ° C., 80% RH) and low temperature low humidity (10 ° C., 20% RH) environments. The evaluation results are shown in Table 2.

Exposure condition Exposure part potential target: Set to an exposure amount to be less than -50V.

Exposure beam: Image exposure with a dot density of 600 dpi (dpi is the number of dots per 2.54 cm) was performed. Laser uses 780 nm semiconductor laser Development condition: Reversal development using non-magnetic one-component developer Evaluation item and evaluation method Evaluation item and evaluation criteria Evaluation of residual potential (change in potential of solid black image)
Under low-temperature and low-humidity (10 ° C., 20% RH) and high-temperature, high-humidity (HH: 30 ° C., 80% RH) environments, a character image with a pixel rate of 7%, a halftone image, a solid white image, and a solid black image are each 1 / An image divided into four equal parts is printed in an A4 single sheet intermittent mode with 10,000 sheets each, and the potential change in the black image part (exposure part potential) at the development position after the initial and 10,000 sheets (|) ΔV |) was evaluated. The smaller the | ΔV |, the smaller the increase in the residual potential.

A: Potential change in solid black image portion | ΔV | is less than 50 V (good)
○: Potential change of solid black image portion | ΔV | is 50 V to 150 V (no problem in practical use)
×: The potential change | ΔV | of the solid black image portion is larger than 150 V (practically problematic)
Leakage resistance: evaluated at low temperature and low humidity (LL: 10 ° C., 20% RH), high temperature and high humidity (30 ° C., 80% RH) ○: No dielectric breakdown of the photoreceptor due to charge leakage at LL or HH.

  X: Dielectric breakdown of the photoreceptor due to charge leakage occurred at LL or HH.

Image unevenness: Evaluation at low temperature and low humidity (LL: 10 ° C., 20% RH), high temperature and high humidity (30 ° C., 80% RH) The evaluation of image unevenness was evaluated with a halftone image.

  A: The halftone image is clearly reproduced, and no image unevenness occurs (good).

  ◯: Although there is a density difference of 0.02 to 0.04 in reflection density in the halftone image, the boundary of the image unevenness is not clear, and the image unevenness is not noticeable unless it is watched (with practicality).

  X: Image unevenness clearly occurs in the halftone image.

From Table 2, the organophotoreceptor of the present invention, that is, the intermediate layer is a mixed solvent of at least two kinds, and the SP value is 2.0 to 2.0 from the main solvent with respect to the main solvent occupying the maximum amount of the mixed solvent. Formed from an intermediate layer composition containing 10 to 40% by mass of an organic solvent having a small 4.0 and a difference in polarity parameter within 1 and having a boiling point lower than that of the main solvent, based on the total mixed solvent; The organic photoreceptors 1 to 8, 13, and 14 having a film thickness of 5 to 40 μm have excellent coatability and form a uniform film thickness, and as a result, the potential characteristics are stable. Good electrophotographic images can be obtained without image unevenness and dielectric breakdown. On the other hand, the photoconductor 9 having an intermediate layer thickness of 4 μm has deteriorated leakage resistance and dielectric breakdown. Further, in the photoreceptor 10 having an intermediate layer thickness of 43 μm, the intermediate layer is too thick, causing unevenness in steps, and the increase in residual potential is significant. Further, in the photoconductor 11 in which the mass ratio of the secondary solvent is 7%, partial step unevenness occurs and image unevenness also occurs. Further, in the photoconductor 11 in which the mass ratio of the secondary solvent is 44%, partial unevenness occurs and image unevenness also occurs. Further, in the photoconductor 15 whose boiling point of the subsolvent is lower than that of the main solvent, unevenness of steps occurs, unevenness of images also occurs, and deterioration of residual potential and deterioration of leak resistance are observed. Further, the photoreceptor 16 using the sub-solvent whose SP value is 4.5 with respect to the main solvent also causes unevenness in the image, unevenness in the image, and deterioration in residual potential and leakage resistance. . Further, the photoreceptor 17 using the sub-solvent whose SP value is 1.1 with respect to the main solvent also causes unevenness in the image, unevenness in the image, and deterioration of the residual potential.

1 is a schematic cross-sectional view of an image forming apparatus 1 using a contact charging method according to the present invention. 2 is a schematic cross-sectional view of a photosensitive cartridge 2 that is detachable from the image forming apparatus 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Photoconductor cartridge 3 Developer cartridge 4 Exposure apparatus 5 Paper feeder 6 Transfer roller 7 Fixing device 8 Paper discharge tray 21 Photoconductor 22 Charging brush 23, 27 Power supply connection member 24 Pre-charge film 25, 26 Charging Element

Claims (6)

Between the electroconductive support and the photosensitive layer, in the manufacturing method of the organic photoreceptor to form an intermediate layer by coating an intermediate layer coating solution containing at least inorganic particles and a binder resin and an organic solvent, wherein the conductive support is An aluminum substrate having a ten-point average roughness Rz of 0.3 to 2.5 μm, the binder resin is an alcohol-soluble polyamide, and the organic solvent is at least two kinds of mixed solvents. Tetrahydrofuran, ethyl acetate and methyl ethyl ketone having a solubility parameter value (SP value) of 2.0 to 4.0 lower than that of the main solvent and a boiling point lower than that of the main solvent with respect to the main solvent of ethanol or n-propyl alcohol occupying a large amount selected sub solvent containing 10 to 40% by weight based on the total solvent mixture, and coating and drying the intermediate layer coating solution onto the conductive support from a, Method of manufacturing an organic photoreceptor thickness and forming an intermediate layer of 5 to 40 m. The method for producing an organic photoreceptor according to claim 1, wherein the inorganic particles are a metal oxide. 3. The method for producing an organic photoreceptor according to claim 1, wherein the inorganic particles are subjected to a surface treatment. The method for producing an organic photoreceptor according to claim 1, wherein the number average primary particle size of the inorganic particles is 3 nm or more and 200 nm or less. The method for producing an organic photoreceptor according to claim 2, wherein the metal oxide is titanium oxide. 6. The method for producing an organic photoreceptor according to claim 1, wherein the secondary solvent is tetrahydrofuran.

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