JP5268407B2 - Electrophotographic photosensitive member and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: an electrophotographic photoreceptor excellent in reproducibility of dots and lines, wherein titanium oxide (TiO<SB>2</SB>) covered with oxygen-deficient SnO<SB>2</SB>advantageous in view of charging lines is used as a conductive layer; and to provide an electrophotographic apparatus having the same. <P>SOLUTION: The electrophotographic photoreceptor includes an electrically conductive support, wherein the electrically conductive support includes thereon at least a conductive layer, an intermediate layer and a photosensitive layer. The conductive layer includes the oxygen-deficient SnO<SB>2</SB>and the covered TiO<SB>2</SB>, wherein the surface of the conductive layer is 0.5 to 1.0 &mu;m in Rzjis and is 10 to 35 &mu;m in Sm. In the electrophotographic apparatus having the electrophotographic photoreceptor and an exposure means, an exposure light of an exposure means is &ge;1,200 dpi in resolution. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an electrophotographic photosensitive member and an electrophotographic apparatus having the electrophotographic photosensitive member.

  In recent years, research and development of electrophotographic photoreceptors (organic electrophotographic photoreceptors) using organic photoconductive materials have been actively conducted.

  An electrophotographic photosensitive member basically includes a support and a photosensitive layer formed on the support. However, the current situation is that the surface of the support is coated with defects, the coating property of the photosensitive layer is improved, the adhesion between the support and the photosensitive layer is improved, the electrical damage of the photosensitive layer is protected, the charging property is improved, and the support is exposed to light. Various layers are often provided between the support and the photosensitive layer in order to improve the charge injection property to the layer. Therefore, the layer provided between the support and the photosensitive layer is required to have many functions such as coverage, adhesiveness, mechanical strength, conductivity, and electrical barrier properties.

Conventionally, the following types are known as layers provided between the support and the photosensitive layer.
(I) A resin layer not containing a conductive material.
(Ii) A resin layer containing a conductive material.
(Iii) A layer obtained by laminating the layer (i) above the layer (ii).

  Since the layer (i) does not contain a conductive material, the resistance of the layer is high. Moreover, in order to cover the defects on the surface of the support that has not been subjected to the surface smoothing treatment, the thickness (film thickness) must be increased.

  However, when the film thickness of the layer (i) having high resistance is increased, there arises a problem that the residual potential at the initial stage and during repeated use is increased.

  Therefore, in order to put the layer (i) to practical use, it is necessary to reduce the defects on the surface of the support and reduce the film thickness.

  On the other hand, the layer (ii) is a layer in which a conductive material such as conductive particles is dispersed in a resin, and since the resistance of the layer can be reduced, the layer thickness is increased, It is possible to cover defects on the surface of a conductive support or a non-conductive support (such as a resin support).

  However, when the thickness of the layer (ii) is increased, it is necessary to impart sufficient conductivity to the layer as compared with the layer (i) to be reduced. Therefore, the layer (ii) The layer has a low volume resistivity. Therefore, in a wide range of environmental conditions from low temperature and low humidity to high temperature and high humidity, in order to prevent charge injection from the layer (ii) above to the photosensitive layer, which causes image defects, a layer having an electrical barrier property Is preferably provided separately between the layer (ii) and the photosensitive layer. The layer having an electrical barrier property is a resin layer that does not contain conductive particles like the layer (i).

  That is, the layer provided between the support and the photosensitive layer preferably has the configuration (iii) in which the layer (i) and the layer (ii) are stacked.

  The structure of (iii) requires a plurality of layers to be formed, and thus the number of processes increases accordingly. However, since the allowable range of defects on the surface of the support is increased, the allowable use range of the support is greatly expanded, and production is performed. There is an advantage that improvement in performance can be achieved.

  In general, the layer (ii) is referred to as a conductive layer, and the layer (i) is referred to as an intermediate layer (conductive layer, barrier layer).

  In addition, an aluminum tube manufactured by a manufacturing method including an extrusion step and a drawing step, and an aluminum tube manufactured by a manufacturing method including an extrusion step and a squeezing step are excellent in dimensional accuracy as a non-cutting tube without surface cutting. Surface smoothness is obtained. In addition, although it is used as a support for an electrophotographic photosensitive member that is advantageous in terms of cost, the surface of these uncut aluminum tubes is likely to have a crust-like convex defect. From the viewpoint of concealing surface defects, the above configuration (iii) is preferable.

Examples of the conductive material used for the conductive layer include various metals, metal oxides, and conductive polymers. Among them, tin oxide (hereinafter also referred to as “SnO ₂ ”) having a powder resistivity in a range of 10 ^{4 to} 10 ⁶ Ω · cm is preferable because of its excellent resistance characteristics. In addition, when the conductive material of SnO ₂ is manufactured, a metal compound having a valence different from tin, such as antimony oxide, a nonmetallic element, or the like is mixed (doped), and the powder resistivity is reduced to 1/1000 or more. There is also a conductive material reduced to 1/10000. In addition, there is an oxygen-deficient SnO ₂ conductive material that is non-doped without increasing the number of constituent elements and the resistance of SnO ₂ is made as low as that of antimony dope.

As a prior art related to oxygen deficient SnO ₂ , for example, Japanese Patent Laid-Open No. 7-295245 (Patent Document 1) discloses a technique using oxygen deficient SnO ₂ for a conductive layer. Japanese Patent Application Laid-Open No. 6-208238 (Patent Document 2) discloses a technique for improving the dispersibility as compared with the case where only barium sulfate particles are coated with oxygen-deficient SnO ₂ and only SnO ₂ is used. . Japanese Patent Application Laid-Open No. 10-186702 (Patent Document 3) uses barium sulfate particles to improve dispersibility, and titanium oxide (TiO ₂ ) is added to improve whiteness thereon. A technique for coating SnO ₂ to coat and further impart electrical conductivity thereon has been disclosed. Japanese Patent Laying-Open No. 2005-107178 (Patent Document 4) discloses an embodiment in which oxygen-deficient SnO ₂ is used for a conductive layer. However, since the surface roughness is large in this configuration, when used in a high-resolution apparatus, the reproducibility of dots and lines is not sufficient, and further, it is difficult to increase the film thickness due to adverse effects such as cracks. In terms of the charged transverse stripe, as disclosed in JP 2007-165023 A (Patent Document 5), an embodiment in which titanium oxide coated with oxygen-deficient SnO ₂ is used for the conductive layer is preferable. However, since the surface roughness is large as in JP-A-2005-107178 (Patent Document 4), when used in a high-resolution apparatus, the reproducibility of dots and lines is not sufficient, and the film thickness that can be increased is also available. Not enough.
JP 7-295245 A JP-A-6-208238 JP-A-10-186702 JP-A-2005-107178 JP 2007-165023 A JP-A-4-154621

  In recent years, there has been a demand for higher image quality of electrophotographic apparatuses, and since the resolution of image exposure has been increasing, electrophotographic photoreceptors are also required to have higher reproducibility of dots and lines. .

An object of the present invention is to provide an electrophotographic photosensitive member having good dot and line reproducibility in an electrophotographic photosensitive member using titanium oxide coated with oxygen-deficient SnO ₂ advantageous for charged transverse stripes as a conductive layer. .

  Another object of the present invention is to provide an electrophotographic apparatus having such an electrophotographic photosensitive member.

According to the present invention, there is provided a conductive support, at least a conductive layer, an intermediate layer, and a photosensitive layer on the conductive support, the conductive layer containing oxygen-deficient SnO ₂ -coated TiO _2, and the surface of the conductive layer Rzjis is not more of 0.99 [mu] m or less 0.74 [mu] m or more, and provided that electronic photoreceptor to wherein the Sm of the surface of the conductive layer is 14.3 [mu] m or more 33.4 [mu] m following Is done.

  In addition, according to the present invention, there is provided an electrophotographic apparatus having the electrophotographic photosensitive member and the exposure means, wherein the exposure light has a resolution of 1200 dpi or more.

According to the present invention, an electrophotographic photosensitive member having good reproducibility of dots and lines in an electrophotographic photosensitive member using titanium oxide coated with oxygen-deficient SnO ₂ advantageous for charged transverse stripes as a conductive layer, and the electrophotographic photosensitive member An electrophotographic apparatus having a body can be provided.

  Hereinafter, embodiments of the present invention will be described in more detail.

  The electrophotographic photosensitive member of the present invention includes a conductive support, a conductive layer formed on the conductive support, an intermediate layer formed on the conductive layer, and a photosensitive layer formed on the intermediate layer. Have

In the present invention, as a conductive material to be contained in the conductive layer, particles obtained by coating SnO ₂ with TiO ₂ particles, which has been made to have a low resistance by depleting oxygen, were used. These particles are referred to as “oxygen deficient SnO ₂ -coated TiO ₂ particles” in the present invention. Due to this low resistance, the resistance of the particles is about 1/10000 in terms of powder resistivity.

Oxygen deficient SnO ₂ is more reusable than SnO ₂ doped with a different element such as antimony. In addition, there is little increase in resistivity under a low humidity environment and a decrease in resistivity under a high humidity environment, and it is excellent in environmental stability.

The reason why the conductive material for the conductive layer used in the present invention is not oxygen-deficient SnO ₂ particles (oxygen-deficient SnO ₂ particles) but oxygen-deficient SnO ₂ -coated TiO ₂ particles is as follows. It is as follows.

First, the core particles (TiO ₂ particles) were used in order to improve the dispersibility of the particles in the conductive layer coating solution. When a conductive layer coating solution is prepared using oxygen-deficient SnO ₂ particles, aggregation of oxygen-deficient SnO ₂ is likely to occur particularly when the content ratio of oxygen-deficient SnO ₂ is high.

Also, were used TiO ₂ particles as the core particles, the affinity of the oxide sites oxygen deficient SnO ₂ oxygen defect sites and TiO ₂ particle surface, binding the coating layer of the oxygen-deficient SnO ₂ and the core member Because is strengthened. Also, unlike the doped type, the oxygen deficient type may be oxidized in the presence of oxygen and the oxygen deficient site may disappear, resulting in a decrease in conductivity (powder resistivity increases). By using TiO ₂ particles, the oxygen deficient sites of oxygen deficient SnO ₂ are protected.

Further, when the exposure light (image exposure light) is laser light, the TiO ₂ particles that are the core material particles interfere with light reflected by the support surface during laser exposure, and interference fringes are generated in the output image. This can be suppressed.

Incidentally, (a method of coating the oxygen-deficient SnO ₂ to a method and TiO ₂ particles to produce an oxygen-deficient SnO ₂₎ oxygen production method of defective SnO ₂ coated TiO ₂ particles, disclosed in Patent Documents 1 and 6 Has been.

  Further, in order to maintain good reproducibility of dots and lines, Rzjis on the surface of the conductive layer must be not less than 0.5 μm and not more than 1.0 μm, and Sm on the surface of the conductive layer must be not less than 10 μm and not more than 35 μm. There is. Preferably, Rzjis is 0.75 μm or more and 1.0 μm or less, and Sm is more preferably 15 μm or more and 25 μm or less. The 60 ° glossiness of the surface is preferably 40 or more and 80 or less. When the surface Rzjis, Sm exceeds the range of the present invention, the coating uniformity of the charge generation layer is deteriorated even when an intermediate layer is provided on the conductive layer. Specifically, the thickness of the charge generation layer in the thick portion of the conductive layer is reduced, and the thickness of the charge generation layer in the thin portion is increased. This film thickness difference is observed as a fine mottle on the appearance, but when it is larger than Rzjis and Sm on the surface of the present invention, the film thickness difference is in a range that affects the density of the latent image, and the mottle appears in the image. It becomes like this. The effect on the image is more significant when the resolution at the time of latent image formation is higher, and is particularly remarkable at a resolution of 1200 dpi or higher. Further, considering only the reproducibility of dots and lines, it is preferable that the surface of the conductive layer is smoother. However, in recent electrophotographic processes using laser light, interference fringes are adversely affected. For this reason, Rzjis and Sm on the surface of the conductive layer must be within the scope of the present invention. Rzjis is defined as Rz in JISB0601 (1994). In JISB0601, Rz was revised by the 2001 standard revision, and replaced with Ry (maximum height) in 1994. Rz in 1994 was renamed Rzjis in 2001 for distinction.

As a method for controlling Rzjis and Sm on the surface of the conductive layer, it can be carried out by a combination of the particle size and amount of the oxygen-deficient SnO ₂ -coated TiO ₂ particles to be used and the dispersion conditions. In the case of a thing with a large particle diameter, it can control to the range of this invention by reducing a ratio with binder resin, or performing dispersion | distribution more strongly. Moreover, in the case of a thing with a small particle diameter, it can control to the range of this invention by raising a ratio with binder resin, or performing dispersion | distribution weakly. The ratio with the binder resin is preferably 1.5 / 1 to 3.5 / 1 in terms of the mass ratio of oxygen-deficient SnO ₂ -coated TiO ₂ particles / binder resin. If it is less than 1.5, the electroconductivity is poor, and if it exceeds 3.5, there is a concern that harmful effects such as cracks may occur. Further, although it is possible to control by addition of roughening particles described later, it is necessary to limit the addition amount so as to be within Rzjis and Sm on the surface of the present invention. The 60 ° gloss is preferably 40 or more and 80 or less for the same reason.

In the present invention, the conductive layer is formed by applying a coating solution for a conductive layer obtained by dispersing oxygen-deficient SnO ₂ -coated TiO ₂ particles together with a binder and a solvent onto a support and drying the coating. be able to. Examples of the dispersion method include a method using a paint shaker, a sand mill, a ball mill, a liquid collision type high-speed disperser and the like.

The following can be illustrated as a solvent used for the coating liquid for conductive layers.
Alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone,
Ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether and propylene glycol monomethyl ether,
Esters such as methyl acetate and ethyl acetate, and aromatic hydrocarbons such as toluene and xylene.

  From the viewpoint of concealing the surface defects of the support, the thickness of the conductive layer is preferably 20 μm or more and 40 μm or less, and more preferably 25 μm or more and 35 μm or less.

  In the present invention, the film thickness of each layer of the electrophotographic photosensitive member including the conductive layer was measured by FISHERSPEPE mms manufactured by Fisher Instruments Co., Ltd.

  Examples of the binder material for the conductive layer include resins (binder resins) such as phenol resin, polyurethane, polyamide, polyimide, polyamideimide, polyvinyl acetal, epoxy resin, acrylic resin, melamine resin, and polyester. These can be used alone or in combination of two or more. In addition, among various resins, from the viewpoints of suppressing migration (melting) to other layers, adhesion to the support, dispersibility / dispersion stability of the conductive material, solvent resistance after film formation, etc., the conductive layer The binder resin is preferably a curable resin, and more preferably a thermosetting resin. Specifically, a thermosetting phenol resin or polyurethane is preferable. When a curable resin is used as the binder resin for the conductive layer, the binder material contained in the conductive layer coating solution is a monomer and / or oligomer of the curable resin.

In addition, a surface roughening material for roughening the surface of the conductive layer is provided on the conductive layer in order to suppress interference fringes in the output image due to interference of the light reflected on the surface of the conductive layer. It is also possible to add. As the surface roughening agent, resin particles having an average particle diameter of 1 μm or more and 8 μm or less are preferable. Examples thereof include curable resin particles such as curable rubber, polyurethane, epoxy resin, alkyd resin, phenol resin, polyester, silicone resin, and acrylic-melamine resin. Among these, silicone resin particles that are difficult to aggregate are preferable. Since the specific gravity (0.5 to 2) of the resin particles is smaller than the specific gravity (4 to 7) of the oxygen-deficient SnO ₂ -coated TiO ₂ particles, the surface of the conductive layer is effectively roughened when forming the conductive layer. Can be However, as the content of the surface roughening imparting material in the conductive layer increases, the surface roughening tends to be roughened. Therefore, the content of the surface roughening imparting material in the conductive layer depends on Rzjis and Sm on the surface of the present invention. It is necessary to limit it to be.

  Further, a leveling agent may be added to improve the surface property of the conductive layer, and pigment particles may be contained in the conductive layer in order to improve the concealing property of the conductive layer.

In order to prevent charge injection from the conductive layer to the photosensitive layer, it is necessary to provide an intermediate layer having an electrical barrier property between the conductive layer and the photosensitive layer. The volume resistivity of the intermediate layer is 1.0 × It is preferably 10 ⁹ Ω · cm or more and 1.0 × 10 ¹³ Ω · cm or less. If the volume resistivity of the intermediate layer is too small, the electrical barrier property becomes poor, and the occurrence of spots and fog due to charge injection from the conductive layer tends to become remarkable. On the other hand, if the volume resistivity of the intermediate layer is too large, the flow of charges (carriers) is stagnant during image formation, and the residual potential tends to increase (lack of potential stability).

  The method for measuring the volume resistivity of the intermediate layer in the present invention is as follows.

  First, an intermediate layer sample (having a film thickness of about 2 μm to 5 μm) was formed on an aluminum sheet using the intermediate layer coating solution. A gold thin film was formed on the intermediate layer sample by vapor deposition. The value of current flowing between both the aluminum sheet and the gold thin film electrode was measured with a pA meter. The measurement environment was 23 ° C./60 RH%, and the applied voltage was 100V. A stable value 1 minute after the start of current value measurement was read, and the volume resistivity of the intermediate layer was derived.

  The intermediate layer can be formed by applying an intermediate layer coating solution containing a binder resin on the conductive layer and drying it.

Examples of the binder resin for the intermediate layer include the following.
Water-soluble resins such as polyvinyl alcohol, polyvinyl methyl ether, polyacrylic acids, methyl cellulose, ethyl cellulose, polyglutamic acid, casein, starch,
Polyamide, polyimide, polyamideimide, polyamic acid, melamine resin, epoxy resin, polyurethane, polyglutamic acid ester, etc.

  In order to effectively develop the electrical barrier properties, the binder resin of the intermediate layer is preferably a thermoplastic resin from the viewpoints of coatability, adhesion, solvent resistance, resistance, and the like. Specifically, a thermoplastic polyamide is preferable. The polyamide is preferably a low crystalline or non-crystalline copolymer nylon that can be applied in a solution state. Moreover, it is preferable that the film thickness of an intermediate | middle layer is 0.1 micrometer or more and 2 micrometers or less.

  Further, in order to prevent the flow of electric charges (carriers) in the intermediate layer, the intermediate layer may contain an electron transport material (electron accepting material such as an acceptor).

  Next, the configuration of the electrophotographic photosensitive member of the present invention will be described.

  As shown in FIG. 1, the electrophotographic photoreceptor of the present invention has a conductive layer 102, an intermediate layer 103, and a photosensitive layer 104 (a charge generation layer 1041 and a charge transport layer 1042) in this order on a conductive support 101. An electrophotographic photoreceptor.

  Even if the photosensitive layer is a single-layer type photosensitive layer 104 containing the charge transport material and the charge generation material in the same layer (see FIG. 1A), the charge generation layer 1041 containing the charge generation material and the charge transport material are transported. It may be a laminated type (functional separation type) photosensitive layer separated into a charge transport layer 1042 containing a substance. From the viewpoint of electrophotographic characteristics, a laminated photosensitive layer is preferred. The laminated photosensitive layer includes a normal photosensitive layer (see FIG. 1B) in which the charge generation layer 1041 and the charge transport layer 1042 are laminated in this order from the support 101 side, and a charge transport layer from the support 101 side. There is a reverse photosensitive layer (see FIG. 1C) in which 1042 and a charge generation layer 1041 are laminated in this order. From the viewpoint of electrophotographic characteristics, a normal layer type photosensitive layer is preferred.

  In addition, a protective layer 105 may be provided over the photosensitive layer 104 (the charge generation layer 1041 and the charge transport layer 1042) (see FIG. 1D).

  As a support body, it is what has electroconductivity (conductive support body), For example, metal supports, such as aluminum, an aluminum alloy, and stainless steel, can be used. In the case of aluminum or an aluminum alloy, an aluminum pipe manufactured by a manufacturing method including an extrusion process and a drawing process or an aluminum pipe manufactured by a manufacturing method including an extrusion process and a squeezing process can be used. Also, those obtained by cutting, electrolytic composite polishing (electrolysis with an electrode having an electrolytic action and an electrolytic solution and polishing with a grindstone having a polishing action), wet or dry honing treatment can be used. In addition, the above metal support or resin support (polyethylene terephthalate, polybutylene terephthalate, phenol resin, polypropylene, polystyrene resin) having a layer formed by vacuum deposition of aluminum, aluminum alloy, indium oxide-tin oxide alloy or the like. Etc.) can also be used. In addition, a support in which a conductive material such as carbon black, tin oxide particles, titanium oxide particles, and silver particles is impregnated with resin or paper, a plastic having a conductive binder resin, or the like can also be used.

In order to allow the electric charge (carrier) of the conductive layer to flow to the ground, the volume resistivity of the conductive support is the layer formed when the surface of the support is formed to impart conductivity. The volume resistivity is preferably 1.0 × 10 ¹⁰ Ω · cm or less. In particular, it is more preferably 1.0 × 10 ⁶ Ω · cm or less.

  A conductive layer is provided on the conductive support, and an intermediate layer is provided on the conductive layer. The conductive layer and the intermediate layer are as described above.

  A photosensitive layer is provided on the intermediate layer.

Examples of the charge generating material used in the electrophotographic photosensitive member of the present invention include the following.
Azo pigments such as monoazo, disazo, trisazo,
Phthalocyanine pigments such as metal phthalocyanine and non-metal phthalocyanine;
Indigo pigments such as indigo and thioindigo,
Perylene pigments such as perylene acid anhydride and perylene imide,
Polycyclic quinone pigments such as anthraquinone and pyrenequinone,
Squarylium dye, pyrylium salt and thiapyrylium salt, triphenylmethane dye,
Inorganic materials such as selenium, selenium-tellurium, amorphous silicon,
Quinacridone pigments, azulenium salt pigments, cyanine dyes, xanthene dyes, quinoneimine dyes, styryl dyes, cadmium sulfide, zinc oxide and the like.

  Among these, metal phthalocyanines such as oxytitanium phthalocyanine, hydroxygallium phthalocyanine, and chlorogallium phthalocyanine are particularly preferable.

When the photosensitive layer is a laminated photosensitive layer, examples of the binder resin used for the charge generation layer include the following.
Polycarbonate, polyester, polyarylate, butyral resin, polystyrene, polyvinyl acetal, diallyl phthalate resin, acrylic resin, methacrylic resin, vinyl acetate resin, phenol resin, silicone resin, polysulfone, styrene-butadiene copolymer, alkyd resin, epoxy resin, Urea resin, vinyl chloride-vinyl acetate copolymer, etc.

  These may be used alone or in combination as a mixture or copolymer.

  The charge generation layer can be formed by applying a charge generation layer coating solution obtained by dispersing a charge generation material together with a binder resin and a solvent and drying the coating solution. Examples of the dispersion method include a method using a homogenizer, an ultrasonic wave, a ball mill, a sand mill, an attritor, a roll mill and the like. The ratio between the charge generating material and the binder resin is preferably in the range of 10: 1 to 1:10, and more preferably in the range of 3: 1 to 1: 1.

  The solvent used in the coating solution for the charge generation layer is selected from the solubility and dispersion stability of the binder resin and charge generation material used, and the organic solvents include alcohols, sulfoxides, ketones, ethers, esters, aliphatic halogens. Hydrocarbons, aromatic compounds and the like.

  When applying the coating solution for the charge generation layer, for example, a coating method such as a dip coating method (dip coating method), a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, a blade coating method, or the like is used. be able to.

  The thickness of the charge generation layer is preferably 5 μm or less, more preferably 0.1 μm or more and 2 μm or less.

  In addition, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers, and the like can be added to the charge generation layer as necessary. In order to prevent the flow of charges (carriers) in the charge generation layer from stagnation, the charge generation layer may contain an electron transport material (an electron accepting material such as an acceptor).

  Examples of the charge transport material used in the electrophotographic photoreceptor of the present invention include triarylamine compounds, hydrazone compounds, styryl compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, triallylmethane compounds, and the like.

When the photosensitive layer is a laminated photosensitive layer, examples of the binder resin used for the charge transport layer include the following.
Acrylic resin, styrene resin, polyester, polycarbonate, polyarylate, polysulfone, polyphenylene oxide, epoxy resin, polyurethane, alkyd resin, unsaturated resin, etc.

  Among these, polymethyl methacrylate (PMMA), polystyrene, styrene-acrylonitrile copolymer, polycarbonate, polyarylate, and diallyl phthalate resin are preferable. Moreover, these can be used individually or in combination as a mixture or copolymer.

  The charge transport layer can be formed by applying a charge transport layer coating solution obtained by dissolving a charge transport material and a binder resin in a solvent and drying it. The ratio of the charge transport material and the binder resin is preferably in the range of 2: 1 to 1: 2 by mass ratio.

The following can be illustrated as a solvent used for the coating liquid for charge transport layers.
Ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate,
Ethers such as dimethoxymethane and dimethoxyethane,
Aromatic hydrocarbons such as toluene and xylene,
Hydrocarbons substituted with halogen atoms such as chlorobenzene, chloroform and carbon tetrachloride.

  When applying the coating solution for the charge transport layer, for example, a coating method such as a dip coating method (dip coating method), a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, a blade coating method, or the like is used. be able to.

  The film thickness of the charge transport layer is preferably 5 μm or more and 40 μm or less, and more preferably 10 μm or more and 20 μm or less from the viewpoint of charge uniformity.

  In addition, an antioxidant, an ultraviolet absorber, a plasticizer, and the like can be added to the charge transport layer as necessary.

  When the photosensitive layer is a single layer type photosensitive layer, the single layer type photosensitive layer is a coating for a single layer type photosensitive layer obtained by dispersing the charge generation material and the charge transport material together with the binder resin and the solvent. It can be formed by applying a liquid and drying it.

  Further, a protective layer may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. The protective layer can be formed by applying a protective layer coating solution obtained by dissolving the various binder resins described above in a solvent and drying the coating solution.

  The thickness of the protective layer is preferably from 0.5 μm to 10 μm, and more preferably from 1 μm to 5 μm.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to these. In the examples, “part” means “part by mass”.

<Example of preparation of coating solution for conductive layer>
(Preparation of coating liquid A for conductive layer)
55 parts of oxygen-deficient SnO ₂ coated TiO ₂ particles (average particle size 0.8 μm, SnO ₂ coverage (mass ratio) is 40%)
36.5 parts of phenol resin as a binder resin (trade name: Priorofen J-325, manufactured by Dainippon Ink & Chemicals, Inc., resin solid content 60%)
A dispersion was prepared by dispersing 35 parts of methoxypropanol as a solvent in a horizontal sand mill using glass beads having a diameter of 1 mm. At this time, the rotational speed of the horizontal sand mill was 800 rpm, and dispersion was performed three times.

In this dispersion,
3.9 parts of silicone resin particles as a material for imparting surface roughness (trade name: Tospearl 120, manufactured by Momentive Co., Ltd., average particle size 2 μm)
0.001 part of silicone oil as leveling agent (trade name: SH28PA, manufactured by Toray Dow Corning Co., Ltd.)
Was added and stirred to prepare a coating liquid A for a conductive layer.

(Preparation of coating liquid B for conductive layer)
59.4 parts of oxygen-deficient SnO ₂ -coated TiO ₂ particles (average particle size 0.8 μm, SnO ₂ coverage (mass ratio) is 40%)
36.5 parts of phenol resin as a binder resin (trade name: Priorofen J-325, manufactured by Dainippon Ink & Chemicals, Inc., resin solid content 60%)
A dispersion was prepared by dispersing 35 parts of methoxypropanol as a solvent in a horizontal sand mill using glass beads having a diameter of 1 mm. At this time, the rotational speed of the horizontal sand mill was 900 rpm, and dispersion was performed three times.

In this dispersion,
8.1 parts of silicone resin particles as a material for imparting surface roughness (trade name: Tospearl 120, manufactured by Momentive Co., Ltd., average particle diameter of 2 μm)
0.001 part of silicone oil as leveling agent (trade name: SH28PA, manufactured by Toray Dow Corning Co., Ltd.)
Was added and stirred to prepare a coating liquid B for a conductive layer.

(Preparation of coating liquid C for conductive layer)
59.4 parts of oxygen-deficient SnO ₂ -coated TiO ₂ particles (average particle size 0.6 μm, SnO ₂ coverage (mass ratio) is 35%)
36.5 parts of phenol resin as a binder resin (trade name: Priorofen J-325, manufactured by Dainippon Ink & Chemicals, Inc., resin solid content 60%)
A dispersion was prepared by dispersing 35 parts of methoxypropanol as a solvent in a horizontal sand mill using glass beads having a diameter of 1 mm. At this time, the rotational speed of the horizontal sand mill was 800 rpm, and dispersion was performed three times.

In this dispersion,
4.1 parts of silicone resin particles as a surface roughening agent (trade name: Tospearl 120, manufactured by Momentive Co., Ltd., average particle size 2 μm)
0.001 part of silicone oil as leveling agent (trade name: SH28PA, manufactured by Toray Dow Corning Co., Ltd.)
Was added and stirred to prepare a coating liquid C for a conductive layer.

(Preparation of coating liquid D for conductive layer)
59.4 parts of oxygen-deficient SnO ₂ -coated TiO ₂ particles (average particle size 0.8 μm, SnO ₂ coverage (mass ratio) is 40%)
36.5 parts of phenol resin as a binder resin (trade name: Priorofen J-325, manufactured by Dainippon Ink & Chemicals, Inc., resin solid content 60%)
A dispersion was prepared by dispersing 35 parts of methoxypropanol as a solvent in a horizontal sand mill using glass beads having a diameter of 1 mm. At this time, the rotational speed of the horizontal sand mill was 1000 rpm, and dispersion was performed three times.

In this dispersion,
8.1 parts of silicone resin particles as a material for imparting surface roughness (trade name: Tospearl 2000B, manufactured by Momentive Co., Ltd., average particle diameter of 6 μm)
0.001 part of silicone oil as leveling agent (trade name: SH28PA, manufactured by Toray Dow Corning Co., Ltd.)
Was added and stirred to prepare a coating liquid D for conductive layer.

(Preparation of coating liquid E for conductive layer)
48.4 parts of oxygen-deficient SnO ₂ -coated TiO ₂ particles (average particle size 0.5 μm, SnO ₂ coverage (mass ratio) 45%)
36.5 parts of phenol resin as a binder resin (trade name: Priorofen J-325, manufactured by Dainippon Ink & Chemicals, Inc., resin solid content 60%)
A dispersion was prepared by dispersing 35 parts of methoxypropanol as a solvent in a horizontal sand mill using glass beads having a diameter of 1 mm. At this time, the rotational speed of the horizontal sand mill was set to 700 rpm, and dispersion was performed three times.

  In this dispersion, 3.6 parts of silicone resin particles (trade name: Tospearl 120, manufactured by Momentive Co., Ltd., average particle size 2 μm) as a surface roughening agent, silicone oil (trade name: SH28PA, as a leveling agent) 0.001 part of Toray Dow Corning Co., Ltd.) was added and stirred to prepare a conductive layer coating solution A.

(Preparation of coating liquid F for conductive layer)
Oxygen-deficient SnO ₂ -coated TiO ₂ particles 70.1 parts (average particle size 0.8 μm, SnO ₂ coverage (mass ratio) is 40%)
36.5 parts of phenol resin as a binder resin (trade name: Priorofen J-325, manufactured by Dainippon Ink & Chemicals, Inc., resin solid content 60%)
A dispersion was prepared by dispersing 35 parts of methoxypropanol as a solvent in a horizontal sand mill using glass beads having a diameter of 1 mm. At this time, the rotational speed of the horizontal sand mill was 1000 rpm, and dispersion was performed four times.

In this dispersion,
4.6 parts of silicone resin particles as a surface roughness imparting material (trade name: Tospearl 120, manufactured by Momentive Co., Ltd., average particle size 2 μm)
0.001 part of silicone oil as leveling agent (trade name: SH28PA, manufactured by Toray Dow Corning Co., Ltd.)
Was added and stirred to prepare a coating solution F for a conductive layer.

(Preparation of coating liquid G for conductive layer)
55 parts of oxygen-deficient SnO ₂ coated TiO ₂ particles (average particle size 0.8 μm, SnO ₂ coverage (mass ratio) is 40%)
36.5 parts of phenol resin as a binder resin (trade name: Priorofen J-325, manufactured by Dainippon Ink & Chemicals, Inc., resin solid content 60%)
A dispersion was prepared by dispersing 35 parts of methoxypropanol as a solvent in a horizontal sand mill using glass beads having a diameter of 1 mm. At this time, the rotational speed of the horizontal sand mill was 500 rpm, and dispersion was performed three times.

In this dispersion,
3.9 parts of silicone resin particles as a material for imparting surface roughness (trade name: Tospearl 120, manufactured by Momentive Co., Ltd., average particle size 2 μm)
0.001 part of silicone oil as leveling agent (trade name: SH28PA, manufactured by Toray Dow Corning Co., Ltd.)
Was added and stirred to prepare a coating solution G for a conductive layer.

(Preparation of coating liquid H for conductive layer)
55 parts of oxygen-deficient SnO ₂ coated TiO ₂ particles (average particle size 0.8 μm, SnO ₂ coverage (mass ratio) is 40%)
36.5 parts of phenol resin as a binder resin (trade name: Priorofen J-325, manufactured by Dainippon Ink & Chemicals, Inc., resin solid content 60%)
A dispersion was prepared by dispersing 35 parts of methoxypropanol as a solvent in a horizontal sand mill using glass beads having a diameter of 1 mm. At this time, the rotational speed of the horizontal sand mill was 1000 rpm, and dispersion was performed 5 times.

In this dispersion,
2.3 parts of silicone resin particles as a material for imparting surface roughness (trade name: Tospearl 120, manufactured by Momentive Co., Ltd., average particle size 2 μm)
0.001 part of silicone oil as leveling agent (trade name: SH28PA, manufactured by Toray Dow Corning Co., Ltd.)
Was added and stirred to prepare a coating liquid H for a conductive layer.

<Example of production of electrophotographic photoreceptor>
(Preparation of electrophotographic photoreceptor 1)
An aluminum cylinder (JIS-A3003, aluminum alloy) having a length of 270 mm and a diameter of 84 mm manufactured by a manufacturing method including an extrusion process and a drawing process was used as a support.

  The conductive layer coating solution A is dip coated on a support in a 23 ° C./60% RH environment, and dried and thermally cured at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 20 μm. did. When Rzjis / Sm of the surface of the conductive layer was measured, it was 0.98 μm / 33.4 μm and the 60 ° gloss was 45.

  In the present invention, Rzjis / Sm is measured according to JIS-B0601 (1994) using a surface roughness meter Surfcoder SE3500 manufactured by Kosaka Laboratory Ltd., feed rate 0.1 mm / s, cut-off λc0. The setting was 8 mm and the measurement length was 2.50 mm. The 60 ° glossiness was measured using PG-1M manufactured by Nippon Denshoku Industries Co., Ltd.

Next, on the conductive layer,
N-methoxymethylated nylon 4.5 parts (trade name: Toresin EF-30T, manufactured by Teikoku Chemical Industry Co., Ltd.)
Copolymer nylon resin 1.5 parts (Amilan CM8000, manufactured by Toray Industries, Inc.)
Is applied in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol by dip coating and dried at 100 ° C. for 10 minutes to obtain a film thickness of 0.8 μm. An intermediate layer was formed.

next,
10 parts of hydroxygallium phthalocyanine (7.5 °, 9.9 °, 16.3 °, 18.6 °, 25.1 ° and 28.1 ° of Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction). Crystal form with strong peak at 3 °)
5 parts of polyvinyl butyral (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.)
250 parts of cyclohexanone was dispersed in a sand mill apparatus using glass beads having a diameter of 1 mm for 1 hour, and then 250 parts of ethyl acetate was added to prepare a charge generation layer coating solution. The charge generation layer coating solution was dip coated on the intermediate layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.16 μm.

  Next, 10 parts of an amine compound having a structure represented by the following formula, and

10 parts of polycarbonate resin (trade name: Z400, manufactured by Mitsubishi Engineering Plastics) was dissolved in a mixed solvent of 30 parts dimethoxymethane / 70 parts chlorobenzene to prepare a coating solution for a charge transport layer. This charge transport layer coating solution was dip-coated on the charge generation layer and dried at 120 ° C. for 30 minutes to form a charge transport layer having a thickness of 18 μm.

  Thus, an electrophotographic photoreceptor 1 having a charge transport layer as a surface layer was produced.

(Preparation of electrophotographic photoreceptor 2)
An electrophotographic photoreceptor 2 was produced in the same manner as the electrophotographic photoreceptor 1 except that the thickness of the conductive layer was changed to 25 μm.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.94 μm / 30.1 μm, respectively, and the 60 ° glossiness was 49.

(Preparation of electrophotographic photoreceptor 3)
An electrophotographic photoreceptor 3 was produced in the same manner as the electrophotographic photoreceptor 1 except that the thickness of the conductive layer was changed to 30 μm.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.93 μm / 28.4 μm, respectively, and the 60 ° glossiness was 53.

(Preparation of electrophotographic photoreceptor 4)
An electrophotographic photoreceptor 4 was produced in the same manner as the electrophotographic photoreceptor 1 except that the thickness of the conductive layer was changed to 40 μm.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.79 μm / 17.9 μm, respectively, and the 60 ° gloss was 72.

(Preparation of electrophotographic photoreceptor 5)
An electrophotographic photoreceptor 5 was produced in the same manner as the electrophotographic photoreceptor 1 except that the conductive layer coating liquid A was changed to the conductive layer coating liquid B.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.99 μm / 32.5 μm, respectively, and the 60 ° glossiness was 47.

(Preparation of electrophotographic photoreceptor 6)
An electrophotographic photoreceptor 6 was produced in the same manner as the electrophotographic photoreceptor 5 except that the thickness of the conductive layer was changed to 30 μm.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.95 μm / 29.4 μm, respectively, and the 60 ° glossiness was 49.

(Preparation of electrophotographic photoreceptor 7)
An electrophotographic photoreceptor 7 was produced in the same manner as the electrophotographic photoreceptor 5 except that the thickness of the conductive layer was changed to 35 μm.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.86 μm / 22.3 μm, respectively, and the 60 ° gloss was 55.

(Preparation of electrophotographic photoreceptor 8)
An electrophotographic photosensitive member 8 was produced in the same manner as the electrophotographic photosensitive member 3 except that the conductive layer coating liquid A was changed to the conductive layer coating liquid C.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.95 μm / 25.6 μm, respectively, and the 60 ° glossiness was 51.

(Preparation of electrophotographic photoreceptor 9)
An electrophotographic photosensitive member 9 was produced in the same manner as the electrophotographic photosensitive member 8 except that the thickness of the conductive layer was changed to 35 μm.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.91 μm / 23.1 μm, respectively, and the 60 ° glossiness was 54.

(Preparation of electrophotographic photoreceptor 10)
An electrophotographic photoreceptor 10 was produced in the same manner as the electrophotographic photoreceptor 8 except that the thickness of the conductive layer was changed to 40 μm.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.74 μm / 14.3 μm, respectively, and the 60 ° gloss was 75.

(Preparation of electrophotographic photoreceptor 11)
An electrophotographic photoreceptor 11 was produced in the same manner as the electrophotographic photoreceptor 2 except that the conductive layer coating liquid A was changed to the conductive layer coating liquid D.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.98 μm / 31.5 μm, respectively, and the 60 ° glossiness was 47.

(Preparation of electrophotographic photoreceptor 12)
An electrophotographic photoreceptor 12 was produced in the same manner as the electrophotographic photoreceptor 11 except that the thickness of the conductive layer was changed to 30 μm.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.96 μm / 29.1 μm, respectively, and the 60 ° glossiness was 56.

(Preparation of electrophotographic photoreceptor 13)
An electrophotographic photoreceptor 13 was produced in the same manner as the electrophotographic photoreceptor 11 except that the thickness of the conductive layer was changed to 35 μm.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.94 μm / 27.3 μm, and the 60 ° glossiness was 59.

(Preparation of electrophotographic photoreceptor 14)
An electrophotographic photosensitive member 14 was produced in the same manner as the electrophotographic photosensitive member 11 except that the conductive layer coating liquid A was changed to the conductive layer coating liquid E.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.95 μm / 31.2 μm, respectively, and the 60 ° glossiness was 41.

(Preparation of electrophotographic photoreceptor 15)
An electrophotographic photoreceptor 15 was produced in the same manner as the electrophotographic photoreceptor 14 except that the thickness of the conductive layer was changed to 30 μm.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.91 μm / 29.1 μm, respectively, and the 60 ° glossiness was 50.

(Preparation of electrophotographic photoreceptor 16)
An electrophotographic photoreceptor 16 was produced in the same manner as the electrophotographic photoreceptor 14 except that the thickness of the conductive layer was changed to 35 μm.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.84 μm / 24.3 μm, respectively, and the 60 ° glossiness was 68.

(Preparation of electrophotographic photoreceptor 17)
An electrophotographic photosensitive member 17 was produced in the same manner as the electrophotographic photosensitive member 3 except that the conductive layer coating liquid A was changed to the conductive layer coating liquid F.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.95 μm / 27.7 μm, and the 60 ° gloss was 60.

(Preparation of electrophotographic photoreceptor 18)
An electrophotographic photoreceptor 18 was produced in the same manner as the electrophotographic photoreceptor 17 except that the thickness of the conductive layer was changed to 35 μm.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.87 μm / 21.5 μm, respectively, and the 60 ° glossiness was 68.

(Preparation of electrophotographic photoreceptor 19)
The electrophotographic photoreceptor 19 was produced in the same manner as the electrophotographic photoreceptor 1 except that the conductive layer coating liquid A was changed to the conductive layer coating liquid G and the thickness of the conductive layer was changed to 15 μm.

  As a result, Rzjis / Sm on the surface of the conductive layer was 1.25 μm / 45.8 μm, respectively, and the 60 ° gloss was 19.

(Preparation of electrophotographic photoreceptor 20)
An electrophotographic photoreceptor 20 was produced in the same manner as the electrophotographic photoreceptor 19 except that the thickness of the conductive layer was changed to 30 μm.

  As a result, many fine cracks were generated on the surface of the conductive layer.

(Preparation of electrophotographic photoreceptor 21)
An electrophotographic photosensitive member 21 was produced in the same manner as the electrophotographic photosensitive member 7 except that the conductive layer coating liquid A was changed to the conductive layer coating liquid H.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.45 μm / 13.8 μm, respectively, and the 60 ° glossiness was 88.

(Preparation of electrophotographic photoreceptor 22)
Except for changing the binder resin of the charge transport layer to a polyarylate resin having a repeating structural unit represented by the following formula (viscosity average molecular weight (Mv): 42000) in the production of the electrophotographic photoreceptor 6, Example 1 and Similarly, an electrophotographic photosensitive member was produced.

The polyarylate resin having a repeating structural unit represented by the above formula has a molar ratio of terephthalic acid structure to isophthalic acid structure (terephthalic acid structure: isophthalic acid structure) of 50:50 (molar ratio).

  In addition, the measuring method of a viscosity average molecular weight (Mv) is as follows.

  First, 0.5 g of a sample was dissolved in 100 ml of methylene chloride, and the specific viscosity at 25 ° C. was measured using a modified Ubbelohde viscometer. Next, the intrinsic viscosity was determined from this specific viscosity, and the viscosity average molecular weight (Mv) was calculated according to the Mark-Houwink viscosity equation.

  As a result, Rzjis / Sm on the surface of the conductive layer was 0.95 μm / 29.4 μm, respectively, and the 60 ° glossiness was 49.

(Examples 1-19 and Comparative Examples 1-3)
The electrophotographic photoreceptor of the present invention produced as described above was mounted on a modified machine of a color copier color image press C1 manufactured by Canon Inc., and the image was evaluated. Details are as follows.

  The color copier color image press C1 was modified so that the spot diameter of the laser beam of the exposure light was changed to 35 μm, and one line image corresponding to 1200 dpi and 600 dpi could be output by switching. The electrophotographic photosensitive member produced was mounted on this modified machine and evaluated.

  The image was evaluated by first outputting a Keima pattern at 1200 dpi to check for the presence of interference fringes. Subsequently, a one-line image of 600 dpi was output, and line reproducibility was confirmed. Further, a one-line image was output at 1200 dpi, and the line reproducibility was confirmed in the same manner.

  The criteria for the evaluation of the line image are as follows.

A: No defect such as chipping in the line B: Slightly chipped portion in the line C: The chip has a chipped portion exceeding 1/2 of the line width. D: The line has a discontinuous portion.

The presence or absence of interference fringes from the halftone image of the Keima pattern,
A: No interference fringes are observed. C: Interference fringes are slightly observed. D: Interference fringes are observed.

  The results are shown in Table 1.

  As can be seen from the above results, the electrophotographic photoreceptor of the present invention can provide an electrophotographic photoreceptor excellent in line reproducibility.

  Moreover, according to the present invention, an electrophotographic apparatus having such an electrophotographic photosensitive member can be provided.

An example of the layer structure of the electrophotographic photosensitive member of the present invention will be shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Support body 102 Conductive layer 103 Intermediate layer 104 Photosensitive layer 1041 Charge generation layer 1042 Charge transport layer 105 Protective layer

Claims (5)

A conductive support, having at least a conductive layer, an intermediate layer, and a photosensitive layer on the conductive support, the conductive layer containing oxygen-deficient SnO ₂ -coated TiO _2, and Rzjis on the surface of the conductive layer is 0 .74 is a [mu] m or more of 0.99 [mu] m or less, and electric Sm of the surface of the conductive layer you wherein a is 14.3 [mu] m or more 33.4 [mu] m or less child photoreceptor.   The electrophotographic photosensitive member according to claim 1, wherein Sm of the conductive layer is 15 μm or more and 25 μm or less. The electrophotographic photosensitive member according to claim 1 or 2 60 ° gloss value of the conductive layer is 40 or more and 80 or less. The electrophotographic photosensitive member according to any one of claims 1 to 3 film thickness of the conductive layer is 25μm or more. In an electrophotographic apparatus having an electrophotographic photosensitive member and exposure means according to any one of claims 1 to 4, an electrophotographic apparatus, wherein the resolution of the exposure light the exposure means is not less than 1200 dpi.