JP2011248063A - Electrophotographic device - Google Patents

Abstract

To provide an electrophotographic apparatus with high fine line reproducibility while maintaining an image with few image defects such as ghosts and black spots not only under normal temperature and normal humidity but also under low temperature and low humidity.
In an electrophotographic apparatus having an exposure means, a charging means, a developing means, a transfer means, and an electrophotographic photosensitive member using a laser light source having an oscillation wavelength λ, the electrophotographic photosensitive member has a conductive layer on a support. An intermediate layer, a charge generation layer, and a charge transport layer in this order; the ten-point average roughness Rzjis of the conductive layer is 0.8 μm or less; the intermediate layer contains an azo pigment, and the azo pigment Satisfying ε · γ · ξ ≧ 1.4, where ε is the molar extinction coefficient at wavelength λ of ε, γ is the molar concentration of the azo pigment in the intermediate layer, and ξ is the film thickness of the intermediate layer; An electrophotographic apparatus, wherein the arithmetic average roughness Ra of the shape is 0.06 μm or more; and the skewness Rsk is −0.5 or more and +1.0 or less.
[Selection] Figure 1

Description

  The present invention relates to an electrophotographic apparatus such as a copying machine, an electrostatic printer, a facsimile machine, a laser printer, and electrostatic recording.

  As an image holding member used in an electrophotographic apparatus, there is a laminated type organic electrophotographic photosensitive member. In a laminated type photoconductor, when laser light is used as an image exposure light source, there arises a problem that interference fringes are generated in a latent image due to multiple reflection of exposure light inside the photoconductor. In order to solve this problem, a technique of roughening the surface of the photoreceptor serving as a reflection surface has been used.

  On the other hand, Patent Document 1 discloses a concept of providing an intermediate layer between a support and a photosensitive layer as a technique for preventing interference fringes, and containing the dye in the intermediate layer to absorb exposure light. Prior to this, Patent Document 2 discloses the idea of dispersing a pigment in an intermediate layer and absorbing exposure light.

  Japanese Patent Application Laid-Open No. H10-228707 discloses a concept of dispersing a pigment in an intermediate layer from the viewpoint different from prevention of interference fringes in order to improve electrical repetition characteristics.

JP 2000-199977 A JP-A-2-82263 JP 2007-163578 A

In order to cope with higher image quality of electrophotographic apparatuses, the diameter of the exposure beam spot has been reduced. For this reason, the roughening of the substrate to prevent interference fringes has an effect on the reproducibility of fine lines.
Therefore, from the viewpoint of fine line reproducibility, it is more effective to provide an intermediate layer between the support and the photosensitive layer as a means for preventing interference fringes, and to absorb exposure light by incorporating a dye in this intermediate layer. It is preferable to surface.

  However, as a result of intensive studies by the present inventors, it has become clear that interference fringes cannot be erased even if a dye is added to the intermediate layer in a state where the substrate is not roughened. This is because the reflectance at the interface between the intermediate layer and the photosensitive layer increases rather as the dye concentration increases, resulting in a new reflecting surface.

  On the other hand, for high quality and colorization in recent years, improvement of image quality degradation due to ghost phenomenon is desired in all environments, especially for low temperature and low humidity, which are severe conditions, and image quality degradation due to durability. Further improvements are desired. However, the film thickness of the intermediate layer has a trade-off relationship with the appearance of the ghost phenomenon.

  Therefore, in order to suppress an increase in the reflectance at the interface between the intermediate layer and the photosensitive layer, if an attempt is made to increase the thickness of the intermediate layer in order to increase the absorbance while keeping the added concentration of the dye low, image quality degradation due to the ghost phenomenon occurs. There was a problem of ending up. In addition, when the thickness of the intermediate layer is increased, there is a problem that the potential fluctuation in a low humidity environment is deteriorated.

  On the contrary, when the film thickness of the intermediate layer is made small, there is a problem that black spots generated due to defects in the substrate and fog generated due to hole injection from the substrate cannot be suppressed.

  The object of the present invention is to solve the above-mentioned problems, and to maintain an image with few image defects such as ghosts and black spots not only under normal temperature and normal humidity but also under low temperature and low humidity, and an electrophotographic image with high fine line reproducibility. To provide an apparatus.

  The present inventors conducted extensive research to achieve the above object.

  First, from the viewpoint of anti-pochi and fog, after reconfirming that it is effective to provide a conductive layer on the support, when the ten-point average roughness Rzjis of the conductive layer is 0.8 μm or less, It was clarified that the fine line reproducibility was good.

  Next, in this state, in order to eliminate interference fringes, investigations were made in the direction of improving the methods described in Patent Documents 1 and 2, and even if the Rzjis of the conductive layer was 0.8 μm or less, an intermediate It has been found that the interference may be extinguished when the absorbance of the layer is sufficiently large and the arithmetic average roughness Ra of the intermediate layer is 0.06 μm or more.

  Furthermore, as a result of intensive studies, the roughening of the intermediate layer was performed by submicron dispersion of the azo pigment without using an additional method such as blasting, and the skewness Rsk of the intermediate layer surface shape was −0.5 or more + 1. It was found that the interference fringes can be eliminated under the above conditions when the ratio is 0.0 or less.

  Conventionally, when a pigment is intended to be dispersed in a photoconductor, it has been devised to use it with a particle size as small as possible, as described in Patent Document 3. The core of the present invention is that it has been found that characteristics are improved by uniformly and stably dispersing a pigment having a particle size that is unthinkable from the past.

  Based on these findings, the present invention has been completed by further studies and provides the following invention.

The present invention relates to an electrophotographic apparatus having an exposure means, a charging means, a developing means, a transfer means, and an electrophotographic photosensitive member using a laser light source having an oscillation wavelength λ;
The electrophotographic photosensitive member is provided with a conductive layer, an intermediate layer, a charge generation layer, and a charge transport layer in this order on a support;
The conductive layer has a ten-point average roughness Rzjis of 0.8 μm or less;
The intermediate layer contains an azo pigment, and the molar absorption coefficient of the azo pigment at the wavelength λ is ε, the molar concentration of the azo pigment in the intermediate layer is γ, and the film thickness of the intermediate layer is ξ γ・ Ξ ≧ 1.4
The filling;
Arithmetic mean roughness Ra of the intermediate layer surface shape is 0.06 μm or more;
The present invention relates to an electrophotographic apparatus having a skewness Rsk of −0.5 or more and +1.0 or less.

（式（２）中、Ｙ_１は式中のベンゼン環と縮合して置換基を有してもよい芳香族炭化水素環または置換基を有してもよい複素環を示し、Ｒ_１及びＲ_２は同一でも異なってもよく、水素原子、置換基を有してもよいアルキル基、置換基を有してもよいアリール基、置換基を有してもよいアラルキル基または置換基を有してもよい複素環基を示し、Ｒ_１及びＲ_２は結合して式中の窒素原子とともに環状アミノ基を形成してもよく、ｐは０または１を示す。） The present invention relates to an electrophotographic apparatus wherein the azo pigment is represented by the following general formula (1).
General formula (1)
Ck _1- (N = N-Cp) _n
(In the formula (1), Ck ₁ represents a substituted or unsubstituted aromatic hydrocarbon group or heterocyclic group which may be bonded directly or via a bonding group, and Cp is a coupler having a phenolic hydroxyl group. -Represents a residue, and at least one of Cp is a coupler residue represented by the following general formula (2), n represents an integer of 1 to 3, provided that -N = N-Cp is the same benzene ring. There is no connection to multiple
General formula (2)

(In formula (2), Y ₁ represents an aromatic hydrocarbon ring which may have a substituent by condensing with a benzene ring in the formula, or a heterocyclic ring which may have a substituent, and R ₁ and R ₂ may be the same or different and has a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, an aralkyl group which may have a substituent or a substituent. And R ₁ and R ₂ may combine to form a cyclic amino group together with the nitrogen atom in the formula, and p represents 0 or 1.)

一般式（４）

（式（３）及び（４） 中、Ｃｋ₂及びＣｋ_３は直接あるいは結合基を介して結合してもよい、置換または非置換の芳香族炭化水素基あるいは複素環基を表わし、Ｒ_３及びＲ_４、Ｒ_５及びＲ_６及びＲ_７は同一でも異なってもよく、Ｒ_３、Ｒ_４、Ｒ_５、Ｒ_６及びＲ_７は置換基を有してもよいアリール基を示し、Ｒ_３とＲ_４、Ｒ_５とＲ_６とＲ_７は同一でも異なってもよい。Ｙ_２、Ｙ_３、Ｙ_４、Ｙ_５及びＹ_６は式中のベンゼン環と縮合して置換基を有してもよい芳香族炭化水素環または置換基を有してもよい複素環を示し、ｑは１または２を示す。） The present invention relates to the above electrophotographic apparatus, wherein the azo pigment is represented by the following general formula (3) or the following general formula (4).
General formula (3)

General formula (4)

(In the formulas (3) and (4), Ck ₂ and Ck ₃ represent a substituted or unsubstituted aromatic hydrocarbon group or heterocyclic group which may be bonded directly or via a bonding group, and R ₃ and R ₄ , R ₅ and R ₆ and R ₇ may be the same or different, and R ₃ , R ₄ , R ₅ , R ₆ and R ₇ represent an aryl group which may have a substituent, and R ₃ and R ₄ , R ₅ , R ₆ and R ₇ may be the same or different, and Y ₂ , Y ₃ , Y ₄ , Y ₅ and Y ₆ may be condensed with a benzene ring in the formula to have a substituent. A good aromatic hydrocarbon ring or a heterocyclic ring which may have a substituent, and q represents 1 or 2.)

  The present invention relates to the above electrophotographic apparatus, wherein the azo pigment has a structure represented by the following general formula (5).

（式（５）中、Ｒ_８及びＲ_９は置換基を有してもよいアリール基を示し、Ｒ_８とＲ_９は同一でも異なってもよい。Ｘはハロゲン原子を示す。） General formula (5)

(In Formula (5), R ₈ and R ₉ represent an aryl group which may have a substituent, and R ₈ and R ₉ may be the same or different. X represents a halogen atom.)

（式（６）中、Ｒ_１０、Ｒ_１１及びＲ_１２は置換基を有してもよいアリール基を示し、Ｒ_１０とＲ_１１とＲ_１２は同一でも異なってもよい。） The present invention relates to the above electrophotographic apparatus, wherein the azo pigment has a structure represented by the following general formula (6).
General formula (6)

(In the formula _(6), R _{10, R 11} and _{R 12} represents an aryl group which may have a _{substituent, R 10} and _{R 11} and _{R 12} may be the same or different.)

  In the present invention, the intermediate layer of the electrophotographic photosensitive member is produced using an azo pigment having a particle size of 0.4 μm to 1.0 μm as an average dispersed particle size in the coating liquid. The present invention relates to an electrophotographic apparatus.

  In the present invention, when the intermediate layer of the electrophotographic photoreceptor disperses the azo pigment, the dispersion is started using the gelled resin, and the temperature during dispersion is 95% to 100% of the gel disappearance temperature. % Of the above-mentioned electrophotographic apparatus.

  According to the present invention, the object of the present invention is to solve the above-mentioned problems, while maintaining an image with few image defects such as ghosts and black spots not only under normal temperature and normal humidity but also under low temperature and low humidity, An electrophotographic apparatus with high reproducibility can be provided.

1 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus including a process cartridge having the electrophotographic photosensitive member of the present invention. It is a figure which shows the image pattern for evaluation.

  In the photoreceptor used in the electrophotographic apparatus of the present invention, a conductive layer, an intermediate layer, a charge generation layer, and a charge transport layer are formed in this order on a support.

  The support may be any conductive material such as a metal such as aluminum, copper, iron, nickel and titanium, and alloys thereof, or a material such as plastic, ceramic and glass. The one that has been. Among these, aluminum or an aluminum alloy of 3000 (Al—Mn), 5000 (Al—Mg), or 6000 (Al—Mg—Si) 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) to reduce the powder resistivity to 1/1000 or more. A conductive material reduced to 1/100000 can also be used. Further, the resistance of the SnO ₂ conductive material of the oxygen-deficient SnO ₂ was reduced to the same extent as antimony-doped can be suitably used in non-doped without increasing constituent elements. Furthermore, TiO ₂ particles coated with an oxygen-deficient SnO ₂ coating are more preferably used.

  Examples of the binder material for the conductive layer include phenol resin, polyurethane, polyamide, polyimide, polyamideimide, polyvinyl acetal, epoxy resin, acrylic resin, melamine resin, and polyester resin (binder resin). These can be used alone or in combination of two or more. In addition, among various resins, from the viewpoint of suppression of 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.

When TiO ₂ particles coated with oxygen-deficient SnO ₂ coating are used as the conductive particles, the mass of oxygen-deficient SnO ₂ -coated TiO ₂ particles (P) and the binder material (B) in the conductive layer coating solution. The ratio (P: B) is preferably in the range of 2.3: 1.0 to 3.3: 1.0. If the amount of oxygen-deficient SnO ₂ -coated TiO ₂ particles is too small, it will be difficult to adjust the volume resistivity of the conductive layer. When oxygen-deficient SnO ₂ coated TiO ₂ particles is too large, the binding of the oxygen-deficient SnO ₂ coated TiO ₂ particles is difficult in the conductive layer, cracks are likely to occur.

Further, it is possible to add a surface roughening material for roughening the surface of the conductive layer.
As the surface roughening agent, resin particles having an average particle diameter of 1 μm or more and 3 μm or less are preferable. Examples thereof include particles of curable resins such as curable rubber, polyurethane, epoxy resin, alkyd resin, phenol resin, polyester, silicone resin, and acrylic-melamine resin. However, the ten-point average roughness Rzjis (JIS B 0601-2001) of the conductive layer tends to increase as the content of the surface roughness imparting material in the conductive layer increases. In order to set the ten-point average roughness Rzjis (JIS B 0601-2001) of the conductive layer to 0.8 μm or less, the content of the surface roughening agent in the conductive layer is based on the binder resin in the conductive layer. It is preferable to adjust so that it may become 10 mass% or less.

  Further, a leveling agent may be added in order to make the ten-point average roughness Rzjis of the conductive layer 0.8 μm or less.

式（２）中、Ｙ_１は式中のベンゼン環と縮合して置換基を有してもよい芳香族炭化水素環または置換基を有してもよい複素環を示し、Ｒ_１及びＲ_２は同一でも異なってもよく、水素原子、置換基を有してもよいアルキル基、置換基を有してもよいアリール基、置換基を有してもよいアラルキル基または置換基を有してもよい複素環基を示し、Ｒ_１及びＲ_２は結合して式中の窒素原子とともに環状アミノ基を形成してもよく、ｐは０または１を示す。
一般式（３）

一般式（４）

一般式（３）及び（４）中、Ｃｋ₂及びＣｋ_３は直接あるいは結合基を介して結合してもよい、置換または非置換の芳香族炭化水素基あるいは複素環基を表わし、Ｒ_３及びＲ_４、Ｒ_５及びＲ_６及びＲ_７は同一でも異なってもよく、Ｒ_３、Ｒ_４、Ｒ_５、Ｒ_６及びＲ_７は置換基を有してもよいアリール基を示し、Ｒ_３とＲ_４、Ｒ_５とＲ_６とＲ_７は同一でも異なってもよい。Ｙ_２、Ｙ_３、Ｙ_４、Ｙ_５及びＹ_６は式中のベンゼン環と縮合して置換基を有してもよい芳香族炭化水素環または置換基を有してもよい複素環を示し、ｑは１または２を示す。 The intermediate layer in the photoreceptor according to the present invention contains an azo pigment.
As a skeleton structure of an azo pigment that can be used in the present application, general formula (1), general formula (3), and general formula (4) are shown.
General formula (1)
Ck _1- (N = N-Cp) _n
Here, in the formula (1), Ck ₁ represents a substituted or unsubstituted aromatic hydrocarbon group or heterocyclic group which may be bonded directly or via a bonding group, and Cp represents a phenolic hydroxyl group. And at least one of Cp is a coupler residue represented by the following general formula (2). n represents an integer of 1 to 3. However, a plurality of —N═N—Cp are not bonded to the same benzene ring.
General formula (2)

In formula (2), Y ₁ represents an aromatic hydrocarbon ring which may have a substituent by condensing with a benzene ring in the formula or a heterocyclic ring which may have a substituent, and R ₁ and R ₂ May be the same or different and each has a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, an aralkyl group which may have a substituent or a substituent. R ₁ and R ₂ may combine to form a cyclic amino group together with the nitrogen atom in the formula, and p represents 0 or 1.
General formula (3)

General formula (4)

In the general formulas (3) and (4), Ck ₂ and Ck ₃ represent a substituted or unsubstituted aromatic hydrocarbon group or heterocyclic group which may be bonded directly or via a linking group, and R ₃ and R ₄ , R ₅ and R ₆ and R ₇ may be the same or different, and R ₃ , R ₄ , R ₅ , R ₆ and R ₇ represent an aryl group which may have a substituent, and R ₃ and R ₄ , R ₅ , R ₆ and R ₇ may be the same or different. Y ₂ , Y ₃ , Y ₄ , Y ₅ and Y ₆ represent an aromatic hydrocarbon ring which may have a substituent by condensing with a benzene ring in the formula or a heterocyclic ring which may have a substituent. , Q represents 1 or 2.

The intermediate layer of the photoreceptor according to the present invention has a molar extinction coefficient at the wavelength λ of the image exposure light source as ε, the molar concentration of the azo pigment in the intermediate layer as γ, and the film thickness of the intermediate layer as ε. γ ・ ξ ≧ 1.4
Meet. For this reason, the compound used suitably is suitably selected according to wavelength (lambda) of an image exposure light source.

（式（５）中、Ｒ_８及びＲ_９は置換基を有してもよいアリール基を示し、Ｒ_８とＲ_９は同一でも異なってもよい。Ｘはハロゲン原子を示す。） For example, when a semiconductor laser having an oscillation wavelength λ of 780 nm to 810 nm, which is currently widely used as an image exposure light source for LBP, is used as an image exposure light source (laser light source), a compound represented by the general formula (5) Are preferably used.
General formula (5)

(In Formula (5), R ₈ and R ₉ represent an aryl group which may have a substituent, and R ₈ and R ₉ may be the same or different. X represents a halogen atom.)

（式（６）中、Ｒ_１０、Ｒ_１１及びＲ_１２は置換基を有してもよいアリール基を示し、Ｒ_１０とＲ_１１とＲ_１２は同一でも異なってもよい。） When a semiconductor laser having an oscillation wavelength λ of 650 nm to 690 nm used as an image exposure light source for a copying machine is used as the image exposure light source, the compound represented by the general formula (6) is preferably used. .
General formula (6)

(In the formula _(6), R _{10, R 11} and _{R 12} represents an aryl group which may have a _{substituent, R 10} and _{R 11} and _{R 12} may be the same or different.)

  Specific examples of the compounds represented by the general formulas (3) and (4) are shown below, but the azo pigments used in the present invention are not limited to the following specific examples, and conversely, as described above. In addition, in the present invention, compounds that are suitably used can be appropriately selected or eliminated depending on the wavelength λ of the image exposure light source.

Exemplary compound (A-1)

Exemplary compound (A-2)

Exemplary compound (A-3)

Exemplary compound (A-4)

Exemplary compound (A-5)

Exemplary compound (A-6)

Exemplary compound (A-7)

Exemplary compound (A-8)

Exemplary compound (A-9)

Exemplary compound (A-10)

Exemplary compound (A-11)

Exemplary compound (A-12)

Exemplary compound (A-13)

Exemplary compound (A-14)

Exemplary compound (A-15)

Exemplary compound (B-1)

Exemplary compound (B-2)

Exemplary compound (C-1)

Exemplary compound (C-2)

Exemplary compound (C-3)

Exemplary compound (C-4)

  In the present invention, the molar extinction coefficient is defined as the absorption capacity per 1 mol of pigment in the state in which the intermediate layer is formed, and the unit is [l / mol · cm]. The molar extinction coefficient in the present invention can be determined from the absorbance of the intermediate layer formed on the transparent substrate, the molar concentration of the intermediate layer, and the film thickness of the intermediate layer. In the present invention, the UV-visible spectrophotometer (Hitachi U-3300) was used to measure the absorbance of the intermediate layer.

In the present invention, the molar extinction coefficient is preferably larger than 3.6 × 10 ⁴ . This is because the larger the extinction coefficient, the thinner the intermediate layer thickness can be designed, and the ghost suppression effect can be obtained. The smaller the P / B ratio, the higher the stability of the coating solution. By request.

  Examples of the binder for the intermediate layer include the following: polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, ethylene-acrylic acid copolymer, casein, polyamide, N-methoxymethylated 6 nylon. , Copolymer nylon, glue and gelatin. Among them, a polyamide resin is preferable, and an N-methoxymethylated 6 nylon resin is particularly preferable because it can interact with an amide bond of a dispersed azo pigment by a hydrogen bond.

  The intermediate layer of the photoreceptor according to the present invention can be formed by applying an intermediate layer coating solution containing an azo pigment, a binder resin, and a solvent in advance, and drying it. In the present invention, in order to increase the dispersion stability of the azo pigment, a method in which a gelled resin is first prepared using a solvent and a resin, and then an organic pigment is dispersed in the gelled resin can be suitably used. . Since the organic pigment can be adsorbed on the surface of the gelled resin by starting the dispersion in the state where the resin and the organic pigment that have been gelled in advance coexist, the pigments reaggregate during the dispersion process. It is possible to prevent and efficiently disperse in a short time.

  Further, in the step of dispersing the gelled resin and the organic pigment in the solvent, when Tr is the gel disappearance temperature (K), the dispersion temperature T (K) is less than Tr and is not less than Tr × 0.95. A technique for reaching the temperature is more preferably used. That is, it is preferable that the temperature during dispersion of the azo pigment is between 95% and 100% of the gel disappearance temperature. By heating the dispersion temperature to near the gel disappearance temperature, it becomes possible to impart flexibility to the gelled resin, making it easier to incorporate finely dispersed organic pigment into the gel, resulting in aggregation of the organic pigment. Is suppressed and the dispersion state is stabilized.

  The “gelled resin” preferably used in the present invention is a resin that can be judged to be in a solid state by performing a solid-liquid determination test in accordance with ASTM D4359-90 standard.

  The gelled resin can be prepared, for example, by the following method. A mixture of the resin and an appropriate solvent is heated and stirred to completely dissolve the resin in the solvent to form a resin solution. Thereafter, the resin solution is allowed to stand to cool or stand to cool to obtain a gelled resin.

  The kind of resin to be gelled can be a known material and is not particularly limited. For example, acrylic resin, allyl resin, alkyd resin, ethyl cellulose resin, ethylene-acrylic acid copolymer, epoxy resin, casein resin, silicone resin, gelatin resin, phenol resin, butyral resin, polyacrylate resin, polyacetal resin, polyamideimide resin, polyamide resin Materials such as polyallyl ether resin, polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polysulfone resin, polyvinyl alcohol resin, polybutadiene resin, polypropylene resin, urea resin, agarose resin, cellulose resin Can be used. Among them, a polyamide resin is preferable, and an N-methoxymethylated 6 nylon resin is particularly preferable in that it can interact with an amide bond by a hydrogen bond to an azo pigment to be dispersed.

  The solvent used for gelling the resin is not particularly limited as long as the resin solution can be prepared. For example, toluene, xylene, tetralin, chlorobenzene, dichloromethane, chloroform, trichloroethylene, tetrachloroethylene, carbon tetrachloride, methyl acetate, Ethyl acetate, propyl acetate, methyl formate, ethyl formate, acetone, methyl ethyl ketone, cyclohexanone, diethyl ether, dipropyl ether, propylene glycol monomethyl ether, dioxane, methylal, tetrahydrofuran, water, methanol, ethanol, n-propanol, isopropanol, butanol, Methyl cellosolve, methoxypropanol, dimethylformamide, dimethylacetamide and dimethyl sulfoxide can be used. One or two or more gelling solvents may be used in combination.

  As a dispersion method of the dispersion liquid, a known dispersion apparatus such as a paint shaker, a ball mill, a sand mill, or a roll mill may be used, and a dispersion method using a dispersion medium may be used, and there is no particular limitation.

The solvent used for dispersion is not particularly limited. For example, toluene, xylene, tetralin, chlorobenzene, dichloromethane, chloroform, trichloroethylene, tetrachloroethylene, carbon tetrachloride, methyl acetate, ethyl acetate, propyl acetate, methyl formate, ethyl formate, acetone , Methyl ethyl ketone, cyclohexanone, diethyl ether, dipropyl ether, propylene glycol monomethyl ether, dioxane, methylal, tetrahydrofuran, water, methanol, ethanol, n-propanol, isopropanol, butanol, methyl cellosolve, methoxypropanol, dimethylformamide, dimethylacetamide and dimethyl Sulfoxide can be used. Dispersing solvents may be used alone or in combination of two or more.
The solid content of the dispersion is not particularly limited and is determined in consideration of the stability and coating properties of the dispersion.

  Before starting the dispersion step, the gel disappearance temperature is confirmed in advance using the same mixture as the mixture to be dispersed in the dispersion step. Specifically, first, the dispersion process is started at a liquid temperature at which the gelled resin in the mixture does not dissolve and disappear. Thereafter, while the liquid temperature is raised at 0.5 ° C./1 min, it is visually confirmed that the gelled resin dissolves and disappears. The temperature at that time is defined as the gel disappearance temperature.

  The average particle diameter of the azo pigment contained in the intermediate layer coating liquid is preferably 0.4 μm to 1.0 μm as the average dispersed particle diameter in the coating liquid. If the average particle diameter of the azo pigment is too large, spots are likely to occur on the appearance of the electrophotographic photosensitive member, and image defects may occur. On the other hand, if the average particle size of the azo pigment is too small, it is difficult to make the arithmetic average roughness Ra (JIS B 0601-2001) of the intermediate layer 0.06 μm or more.

The average particle diameter of the azo pigment in the intermediate layer coating solution is the median diameter, and was measured using a centrifugal sedimentation particle size distribution analyzer CAPA-700 (manufactured by Horiba, Ltd.). In addition, about the sample density which is a parameter required at the time of a centrifugal sedimentation type particle size distribution measurement, specific gravity (g / cm < ³ >) of the azo pigment contained in the coating liquid for intermediate | middle layers was calculated | required with the pycnometer method.

  The film thickness of the intermediate layer of the photoreceptor according to the present invention is preferably 3 μm or less. If it exceeds 3 μm, the endurance potential fluctuation is deteriorated, which is not preferable. From the viewpoint of preventing image deterioration due to ghost, it is more preferably less than 0.8 μm. On the other hand, from the viewpoint of preventing fogging, it is preferably thicker than 0.4 μm.

  The arithmetic mean roughness Ra (JIS B 0601-2001) of the intermediate layer of the photoreceptor according to the present invention is 0.06 μm or more, and the skewness Rsk (JIS B 0601-2001) is −0.5 or more and +1.0 or less. is there. If the surface state of the intermediate layer is not satisfied, the interference fringes are not necessarily erased even if ε · γ · ξ ≧ 1.4 is achieved. Ra and Rsk were measured using Surfcorder SE3500 manufactured by Kosaka Laboratory.

  Examples of the charge generation material used in the charge generation layer of the electrophotographic photoreceptor according to the present invention include azo pigments such as monoazo, disazo, and trisazo, phthalocyanine pigments such as metal phthalocyanine and nonmetal phthalocyanine, indigo, Indigo pigments such as thioindigo, perylene pigments such as perylene anhydride and perylene imide, polycyclic quinone pigments such as anthraquinone and pyrenequinone, squarylium dyes, pyrylium salts, thiapyrylium salts, triphenylmethane Dyes, inorganic substances such as selenium, selenium-tellurium, amorphous silicon, quinacridone pigments, azulenium salt pigments, cyanine dyes, xanthene dyes, quinoneimine dyes, styryl dyes, cadmium sulfide, and zinc oxide. Can be mentioned. These charge generation materials may be used alone or in combination of two or more.

  Among the above various charge generation materials, azo pigments and phthalocyanine pigments are preferable because they are highly sensitive and the present invention works more effectively. In addition, in order to increase the sensitivity by increasing the thickness of the charge transport layer, the present invention is utilized to the maximum extent from the viewpoint that ghosts are easily generated when a phthalocyanine pigment is used. When the phthalocyanine pigment is used in combination with another charge generation material, the phthalocyanine pigment is preferably 50% by mass or more based on the total mass of the charge generation material.

  Among the phthalocyanine pigments, metal phthalocyanine pigments are preferable, and oxytitanium phthalocyanine, chlorogallium phthalocyanine, dichlorotin phthalocyanine, and hydroxygallium phthalocyanine are more preferable, and among these, hydroxygallium phthalocyanine is particularly preferable.

  Examples of oxytitanium phthalocyanine include crystalline oxytitanium having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction. Phthalocyanine crystals and 9.5 °, 9.7 °, 11.7 °, 15.0 °, 23.5 °, 24.1 ° and 27 with Bragg angles 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction Crystalline oxytitanium phthalocyanine crystals having a strong peak at 3 ° are preferred.

  As chlorogallium phthalocyanine, a crystalline form of chlorogallium having strong peaks at 7.4 °, 16.6 °, 25.5 ° and 28.2 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction Phthalocyanine crystals and crystal forms of chlorogallium phthalocyanine crystals having strong peaks at 6.8 °, 17.3 °, 23.6 ° and 26.9 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction In addition, it has strong peaks at 8.7 to 9.2 °, 17.6 °, 24.0 °, 27.4 ° and 28.8 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction. Crystalline chlorogallium phthalocyanine crystals are preferred.

  As dichlorotin phthalocyanine, Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction is 8.3 °, 12.2 °, 13.7 °, 15.9 °, 18.9 ° and 28.2 °. Crystalline dichlorotin phthalocyanine crystal having strong peaks, and strong peaks at 8.5, 11.2 °, 14.5 ° and 27.2 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction Dichlorotin phthalocyanine crystals having a crystal form of 8.7 °, 9.9 °, 10.9 °, 13.1 °, 15.2 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction , 16.3 °, 17.4 °, 21.9 °, and 25.5 ° in the form of dichlorotin phthalocyanine crystals having a strong peak, or 9 with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction .2 °, 12.2 °, 13. °, 14.6 °, preferably crystalline form of dichlorotin phthalocyanine crystal having strong diffraction peaks at 17.0 ° and 25.3 °.

  Examples of hydroxygallium phthalocyanine include a hydroxygallium phthalocyanine crystal having a crystal form having strong peaks at 7.3 °, 24.9 °, and 28.1 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction, and CuKα Strong against 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 ° and 28.3 ° with Bragg angle 2θ ± 0.2 ° in characteristic X-ray diffraction Crystalline hydroxygallium phthalocyanine crystals having a peak are preferred.

In the present invention, the Bragg angle in CuKα characteristic X-ray diffraction of the crystal form of the phthalocyanine crystal was measured under the following conditions.
Measuring device: Fully automatic X-ray diffractometer manufactured by Mac Science (trade name: MXP18)
X-ray tube: Cu, tube voltage: 50 kV, tube current: 300 mA,
Scan method: 2θ / θ scan, scan speed: 2 deg. / Min, sampling interval: 0.020 deg. ,
Start angle (2θ): 5 deg. Stop angle (2θ): 40 deg. ,
Divergence slit: 0.5 deg. Scattering slit: 0.5 deg. , Receiving slit: 0.3 deg. ,
Uses curved monochromator.

  The particle size of the charge generation material is preferably 0.5 μm or less, more preferably 0.3 μm or less, and still more preferably 0.01 to 0.2 μm.

  Examples of the binder resin used for the charge generation layer include acrylic resin, allyl resin, alkyd resin, epoxy resin, diallyl phthalate resin, silicone resin, styrene-butadiene copolymer, cellulose resin, nylon, phenol resin, butyral resin, benzal. Resin, Melamine resin, Polyacrylate resin, Polyacetal resin, Polyamideimide resin, Polyamide resin, Polyallyl ether resin, Polyarylate resin, Polyimide resin, Polyurethane resin, Polyester resin, Polyethylene resin, Polycarbonate resin, Polystyrene resin, Polysulfone resin, Polyvinyl Acetal resin, polyvinyl methacrylate resin, polyvinyl acrylate resin, polybutadiene resin, polypropylene resin, methacrylic resin, urea resin Vinyl chloride - vinyl acetate copolymer, vinyl acetate resins, and vinyl chloride resin. In particular, a butyral resin is preferred. These can be used alone or as a mixture or copolymer of two or more.

  Such a charge generation layer can be formed by applying a charge generation layer coating solution containing a charge generation material, a binder resin, and a solvent in advance and then drying it. A solution containing the charge generating substance, the binder resin and the solvent is obtained by dispersing the charge generating substance together with the binder resin and the solvent. Examples of the dispersion method include a method using a homogenizer, an ultrasonic disperser, a ball mill, a sand mill, a roll mill, a vibration mill, an attritor, and a liquid collision type high-speed disperser. The ratio between the charge generating material and the binder resin is preferably in the range of 1: 0.3 to 1: 4 (mass ratio).

  The solvent used in the coating solution for the charge generation layer is selected from the viewpoint of the solubility and dispersion stability of the binder resin, the charge generation material and the electron transport material to be used. As the organic solvent, alcohol, sulfoxide, ketone, Examples include ethers, esters, aliphatic halogenated hydrocarbons, and aromatic compounds.

  The film thickness of the charge generation layer is preferably 0.05 to 2.00 μm. When a phthalocyanine pigment is used as the charge generation material, it is more preferably 0.14 μm or less from the viewpoint of preventing image deterioration due to ghost. preferable.

  In addition, various sensitizers, antioxidants, ultraviolet absorbers, and plasticizers can be added to the charge generation layer as necessary.

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, and triarylmethane compounds. These hole transport materials may be used alone or in combination of two or more.
Examples of the binder resin used for the charge transport layer include acrylic resin, acrylonitrile resin, allyl resin, alkyd resin, epoxy resin, silicone resin, nylon, phenol resin, phenoxy resin, butyral resin, polyacrylamide resin, polyacetal resin, Polyamideimide resin, polyamide resin, polyallyl ether resin, polyarylate resin, polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polystyrene resin, polysulfone resin, polyvinyl butyral resin, polyphenylene oxide resin, polybutadiene resin , Polypropylene resin, methacrylic resin, urea resin, vinyl chloride resin, and vinyl acetate resin. Among these, polyarylate resin and polycarbonate resin are preferable, and polyarylate resin is particularly preferable.

（式（７）中、Ｒ_３１〜Ｒ_３４は、それぞれ独立して、水素、炭素数１〜３までのアルキル基、フェニル基、炭素数１〜３までのアルコシキ基を示し、少なくとも１つの部位はアルキル基を有する。Ｘは、単結合、酸素原子、硫黄原子、

を示す。Ｒ_３５、Ｒ_３６は水素原子、炭素数１〜３のアルキル基、アリール基、およびＲ_３５とＲ_３６が結合することによって形成させるアルキリデン基、フルオレニリデン基を示す。Ｙは２価の有機基を示す） Among the polyarylate resins, polyarylate resins having a repeating structural unit represented by the following formula (7) are preferable.
Formula (7)

(In formula (7), R _{31 to} R ₃₄ each independently represent hydrogen, an alkyl group having 1 to 3 carbon atoms, a phenyl group, an alkoxy group having 1 to 3 carbon atoms, and at least one site. Has an alkyl group, X is a single bond, oxygen atom, sulfur atom,

Indicates. R ₃₅ and R _{36 each} represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an aryl group, an alkylidene group or a fluorenylidene group formed by combining R ₃₅ and R ₃₆ . Y represents a divalent organic group)

  The weight average molecular weight of the binder resin is preferably 50,000 to 200,000, and more preferably 100,000 to 180,000.

In the present invention, the weight average molecular weight was determined by measuring the molecular weight distribution using gel permeation chromatography HLC-8120 manufactured by Tosoh Corporation and calculating in terms of polystyrene. Tetrahydrofuran (THF) was used as the developing solvent, and the sample to be measured was a 0.1% by mass solution. As the column, an exclusion limit molecular weight (polystyrene equivalent) 4 × 10 ⁶ column (trade name: TSKgel SuperHM-N, manufactured by Tosoh Corporation) was used, and RI was used as the detector. The column temperature was 40 ° C., the injection volume was 20 μl, and the flow rate was 1.0 ml / min.

  The above resins can be used alone or as a mixture or copolymer of two or more.

  The charge transport layer can be formed by applying a hole transport layer coating solution obtained by dissolving a hole transport material and a binder resin in a solvent, and drying it. The ratio of the hole transport material is preferably in the range of 30% by weight to 70% by weight with respect to the mass of the whole hole transport layer.

  Solvents used in the charge transport layer coating solution include acetone, ketones such as methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, 1,4-dioxane, and tetrahydrofuran. Hydrocarbons substituted with halogen atoms such as ether, chlorobenzene, chloroform, carbon tetrachloride are used.

  The thickness of the charge transport layer is preferably 5 to 40 μm, and more preferably 10 to 30 μm.

  Note that a protective layer for protecting the charge transport layer may be provided on the charge transport layer. The protective layer can be formed by applying a protective layer coating solution obtained by dissolving a binder resin in a solvent and drying the coating solution. Alternatively, the protective layer may be formed by applying a protective layer coating solution obtained by dissolving a binder resin monomer / oligomer in a solvent and then curing and / or drying. For curing, light, heat, or radiation (such as an electron beam) can be used.

  The various resins described above can be used as the binder resin for the protective layer.

  Further, conductive particles such as conductive tin oxide and conductive titanium oxide may be dispersed in the protective layer for the purpose of resistance control.

  The thickness of the protective layer is preferably 0.2 to 10 μm, and particularly preferably 1 to 5 μm.

  When applying the coating liquid for each of the above layers, for example, an application method such as dip coating (dip coating), spray coating, spinner coating, roller coating, Meyer bar coating, or blade coating is used. be able to.

  In addition, the surface layer of the electrophotographic photosensitive member is made of polytetrafluoroethylene, polyvinylidene fluoride, fluorine-based graft polymer, silicone-based graft polymer, fluorine-based block polymer, silicone for the purpose of improving cleaning properties and wear resistance. Lubricants such as block polymers and silicone oils may be added, and antioxidants such as hindered phenols and hindered amines may be added for the purpose of improving weather resistance, and the strength will be reinforced. For this purpose, a film strength reinforcing agent such as silicon may be added.

  When the protective layer is provided, the protective layer is the surface layer of the electrophotographic photosensitive member, and when the protective layer is not provided, the hole transport layer is the surface layer of the electrophotographic photosensitive member.

  FIG. 1 shows an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention. In FIG. 1, reference numeral 1 denotes a cylindrical electrophotographic photosensitive member, which is rotationally driven in a direction of an arrow about a shaft 2 at a predetermined peripheral speed. The surface of the electrophotographic photoreceptor 1 to be rotationally driven is uniformly charged to a predetermined positive or negative potential by a contact charging means 3 having a contact charging member (charging roller or the like), and then exposed by laser beam scanning exposure. Exposure light (image exposure light) 4 output from (not shown) is received. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the surface of the electrophotographic photosensitive member 1. The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed with toner contained in the developer of the developing means 5 to become a toner image. Next, the toner image formed and supported on the surface of the electrophotographic photoreceptor 1 is transferred from a transfer material supply means (not shown) to the electrophotographic photoreceptor 1 and the transfer means by a transfer bias from a transfer means (transfer roller or the like) 6. 6 (contact portion) is sequentially transferred onto a transfer material (paper or the like) P taken out and fed in synchronization with the rotation of the electrophotographic photosensitive member 1. The transfer material P that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member 1 and introduced into the fixing means 8 to receive the image fixing, and is printed out as an image formed product (print, copy). Is done. The surface of the electrophotographic photosensitive member 1 after the transfer of the toner image is cleaned by a cleaning means (cleaning blade or the like) 7 to remove the developer (toner) remaining after transfer, and further from a pre-exposure means (not shown). After being subjected to charge removal processing by pre-exposure light (not shown), it is repeatedly used for image formation. In addition, when the charging unit is a contact charging unit as in the present invention, pre-exposure is not always necessary.

  The above-described electrophotographic photosensitive member 1 and contact charging means 3 are housed in a container and integrally coupled as a process cartridge, and the process cartridge is detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. It may be configured. In FIG. 1, an electrophotographic photosensitive member 1, a contact charging unit 3, a developing unit 5 and a cleaning unit 7 are integrally supported to form a cartridge, and an electrophotographic unit is used by using a guide unit 10 such as a rail of an electrophotographic apparatus main body. The process cartridge 9 is detachable from the apparatus main body.

  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 preparing intermediate layer coating solution)
160 parts of N-methoxymethylated nylon (trade name: EF30-T, Nagase ChemteX) was added to 840 parts of ethanol (manufactured by Kishida Chemical Co., Ltd., special grade) and stirred to obtain a mixed solution. Next, this mixed solution was heated at 50 ° C. to dissolve the polyamide resin to obtain a resin solution. Then, it left still for 24 hours in 23 degreeC environment. The liquid mixture thus obtained is subjected to a liquid-solid determination test based on ASTM D4359-90, confirmed to be solid, and a polyamide resin gel having a solid content of 16.0% is obtained. It was confirmed. The gel disappearance temperature was 317K.

  The polyamide resin gel was crushed to a size of 2 mm or less while being crushed with a sieve (a sieve opening of 2.0 mm). Next, using an 800 ml scale batch type vertical sand mill (K-800, manufactured by Kanada Rika Kogyo Co., Ltd., disk diameter: 7 cm, number of disks: 5), 125 parts of crushed polyamide resin gel, ethanol (manufactured by Kishida Chemical, 77 parts of special grade) and 500 parts of 1 mmφ glass beads (GB201M, manufactured by Potters Barotini) were added. Subsequently, it was dispersed at 1300 rpm for 30 minutes to obtain a mixed solution of polyamide resin and ethanol.

  Next, 16 parts of an organic pigment (specific gravity 1.368 g / ml) represented by the exemplary compound (A-1) was added and further dispersed at 400 rpm for 60 minutes. The liquid temperature during the dispersion step was controlled to a maximum temperature of 305K and a minimum temperature of 302K. Thereafter, 436 parts of ethanol (manufactured by Kishida Chemical Co., Ltd., special grade) and 316 parts of propylene glycol monomethyl ether (manufactured by Kishida Chemical Co., Ltd., grade 1) are added, and the glass beads are removed using nylon mesh (material nylon 66, mesh size 200 mesh). The solution was filtered through a polyflon filter (PF020, pore size 2 μm, manufactured by Advantech Toyo Co., Ltd.) to obtain an intermediate layer coating solution.

(Evaluation example of intermediate layer)
This intermediate layer coating solution was dip-coated on a support on which a PET film was wrapped, and dried at 90 ° C. for 5 minutes to form an intermediate layer having a thickness of 0.6 μm. By changing the coating speed, an intermediate layer having a film thickness of 0.7 μm and 0.8 μm was also coated on the PET film.
The absorbance at 780 nm of this PET film is 1.40 when the film thickness is 0.6 μm.
Absorbance 1.63 when film thickness is 0.7μm
When the film thickness is 0.8 μm, the absorbance is 1.87.
Met.
Taking the average from the above data, ε of the exemplified compound (A-1) was calculated to be 4.73 × 10 ⁵ , [mol ⁻¹ L cm ⁻¹ ].

(Example of production of electrophotographic photoreceptor)
(Preparation of electrophotographic photoreceptor D-1)
-Support body Aluminum cylinder (JIS-A3003, aluminum alloy ED pipe, Showa aluminum (JIS-A3003) obtained by hot extrusion in an environment of temperature 23 ° C and humidity 60% RH. Co., Ltd.) was used as a support.

-Conductive layer The following material was disperse | distributed for 3 hours with the sand mill using the glass bead of diameter 1mm, and the dispersion liquid was prepared.
Oxygen-deficient SnO ₂ coated TiO ₂ particles (powder resistivity 100 Ω · cm, SnO ₂ coverage (mass ratio) 40%) 55 parts phenolic resin (trade name: Pryofen J-325, Dainippon Ink & Chemicals, Inc.) (Co., Ltd., resin solid content 60%) 36.5 parts.
35 parts of 1-methoxy-2-propanol.
The following materials were added to the dispersion and stirred to prepare a coating solution for a conductive layer.
0.8 parts of silicone resin particles (trade name: Tospearl 120, manufactured by GE Toshiba Silicone Co., Ltd., average particle size 2 μm).
0.001 part of silicone oil (trade name: SH28PA, manufactured by Toray Dow Corning Co., Ltd.).
This conductive layer coating solution was dip-coated on a support, dried and thermally cured at a temperature of 140 ° C. for 30 minutes to form a conductive layer having an average film thickness of 15 μm at a position of 130 mm from the upper end of the support.
The ten-point average roughness Rzjis on the surface of the conductive layer was measured and found to be 0.4 μm.
In the present invention, Rzjis is measured according to JIS-B0601 (1994), using a surface roughness meter Surfcoder SE3500 manufactured by Kosaka Laboratory, feed rate 0.1 mm / s, cutoff λc 0.8 mm, The measurement length was set to 2.50 mm.

-Formation and evaluation of intermediate layer The intermediate layer coating solution described above was dip coated on the conductive layer and dried at 90 ° C for 5 minutes to form an intermediate layer having a thickness of 0.7 µm. Table 1 shows the physical properties of the azo pigment contained in the intermediate layer and the intermediate layer.

Charge generation layer Next, a crystalline hydroxygallium phthalocyanine crystal having a strong peak at 7.3 °, 24.9 °, and 28.1 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction (charge) (Generating material) 20 parts, polyvinyl butyral resin (trade name: BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 350 parts of cyclohexanone were dispersed in a sand mill using glass beads having a diameter of 1 mm for 3 hours. Then, 1200 parts of ethyl acetate was added (dispersed particle size measured by CAPA-700 of charge generation material at this time (manufactured by Horiba, Ltd.) was 0.15 μm) to prepare a coating solution for charge generation layer.
This 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 0.14 μm.

下記式（９）で示される化合物（正孔輸送物質）１部、

および、下記式（１０）で示される繰り返し構造単位（ビスフェノールＣ型）を有するポリアリレート樹脂（テレフタル酸骨格とイソフタル酸骨格の質量比：テレフタル酸／イソフタル酸＝５０／５０）５部

を、モノクロロベンゼン５０部／ジクロロメタン１０部の混合溶媒に溶解させ正孔輸送層用塗布液とした。
この正孔輸送層用塗布液を電荷発生層上に浸漬塗布し、これを１時間１１０℃で乾燥させることによって、膜厚が１８μｍの正孔輸送層を形成した。
このようにして、支持体、導電層、中間層、電荷発生層および正孔輸送層をこの順に有し、該正孔輸送層が表面層である電子写真感光体を作製した。感光体の物性を表１に示す。 -Charge transport layer Next, 9 parts of a compound (hole transport material) having a structure represented by the following formula (8),

1 part of a compound represented by the following formula (9) (hole transport material),

And 5 parts of a polyarylate resin having a repeating structural unit (bisphenol C type) represented by the following formula (10) (mass ratio of terephthalic acid skeleton to isophthalic acid skeleton: terephthalic acid / isophthalic acid = 50/50)

Was dissolved in a mixed solvent of 50 parts of monochlorobenzene / 10 parts of dichloromethane to obtain a coating solution for a hole transport layer.
This hole transport layer coating solution was dip-coated on the charge generation layer and dried at 110 ° C. for 1 hour to form a hole transport layer having a thickness of 18 μm.
Thus, an electrophotographic photosensitive member having a support, a conductive layer, an intermediate layer, a charge generation layer, and a hole transport layer in this order, and the hole transport layer being a surface layer was produced. Table 1 shows the physical properties of the photoreceptor.

<Photoconductors D-2 to D-5>
Photoconductors D-2 to D-5 were prepared in the same manner as the photoconductor D-1, except that the pigment used for the intermediate layer was changed as shown in Table 1 when the photoconductor D-1 was prepared. Went. The results are shown in Table 1.

<Photoconductors D-6 to D-15, D-19 to D-31>
Photoconductor D- was the same as Photoconductor D-1, except that the pigment used for the intermediate layer, the concentration ratio of the pigment, and the intermediate layer thickness were changed as shown in Table 1 when producing Photoconductor D-1. 6-D-15 and D-19-D-31 were produced and evaluated for physical properties. The results are shown in Table 1.

<Photosensitive member D-16>
When producing the photoreceptor D-1, the binder resin used for the intermediate layer was changed from 160 parts of N-methoxymethylated nylon (trade name: EF30-T, Nagase ChemteX) to N-methoxymethylated nylon (trade name). : EF30-T, Nagase Chemtex) 100 parts of nylon and 66 parts of nylon 6-66-610-12 quaternary nylon copolymer resin (trade name: CM8000, manufactured by Toray Industries, Inc.) Photoconductor D-4 Photoconductor D-16 was prepared in the same manner as described above, and physical properties were evaluated. The results are shown in Table 1.

<Photosensitive member D-17>
Photosensitive body D-17 was prepared in the same manner as photosensitive body D-4 except that the intermediate layer coating solution was changed as follows when manufacturing photosensitive body D-4, and physical properties were evaluated. The results are shown in Table 1.

(Preparation of intermediate layer coating solution)
5 parts of N-methoxymethylated nylon (trade name: EF30-T, Nagase ChemteX) was added to 95 parts of methanol (manufactured by Kishida Chemical Co., Ltd., special grade) and stirred to obtain a mixed solution. To this mixed solution, 4 parts of the organic pigment represented by the exemplary compound (A-4) was added and dispersed for 3 hours in a sand mill using glass beads having a diameter of 1 mm to prepare an intermediate layer coating solution.

<Photosensitive member D-18>
At the time of production of the photoconductor D-4, the photoconductor D-18 was prepared in the same manner as the photoconductor D-4 except that the intermediate layer coating solution was changed as follows and the intermediate layer thickness was changed to 1.8 μm. It produced and evaluated the physical property. The results are shown in Table 1.

(Preparation of intermediate layer coating solution)
“3 parts of N-methoxymethylated nylon (trade name: EF30-T, Nagase ChemteX) and 2 parts of nylon 6-66-610-12 quaternary nylon copolymer resin (trade name: CM8000, manufactured by Toray Industries, Inc.) In addition to 95 parts of methanol (made by Kishida Chemical Co., Ltd., special grade), the mixture was stirred to obtain a mixed solution.
To this mixed solution, 10 parts of an organic pigment represented by the exemplary compound (A-4) was added and dispersed for 3 hours by a sand mill using glass beads having a diameter of 1 mm to prepare a coating solution for an intermediate layer.

<Photosensitive members E-1, E-5, E-8 to E-10>
Photosensitive member E- 1 was the same as photosensitive member D- 1 except that the pigment used in the intermediate layer, the pigment concentration ratio, and the intermediate layer thickness were changed as shown in Table 2 when producing photosensitive member D-1. 1, E-5, E-8 to E-10 were prepared, and physical properties were evaluated. The results are shown in Table 2.

<Photoreceptors E-2 to E-4>
At the time of preparation of the photoconductor D-18, the photoconductor E- was the same as the photoconductor D-1 except that the pigment used in the intermediate layer, the pigment concentration ratio, and the intermediate layer thickness were changed as shown in Table 2. 2 to E-4 were prepared and physical properties were evaluated. The results are shown in Table 2.

<Photoreceptor E-6>
Photoconductor E-6 was prepared in the same manner as Photoconductor D-1, except that the method for dispersing the pigment was changed at the time of preparation of Photoconductor D-13, and physical properties were evaluated. The results are shown in Table 2.

<Photoreceptor E-7>
At the time of production of photoconductor D-13, photoconductor E-7 was produced in the same manner as photoconductor D-1, except that the method of dispersing the pigment was changed, and the intermediate layer was coated and then blasted. The physical properties were evaluated. The results are shown in Table 2.

<Photoreceptors E-11 to E-13>
Photoconductors D-11 to E-13 were prepared in the same manner as the photoconductor D-1, except that the conductive layer was changed as shown in Table 2, and physical properties were evaluated. . The results are shown in Table 2.

In Tables 1 and 2, the liquid stability of the pigment in the intermediate layer coating liquid was evaluated according to the following criteria:
A: Liquid stability is good B: Liquid stability is normal C: Liquid stability is bad

(Examples 1-34 and Comparative Examples 1-16)
The produced electrophotographic photosensitive member was mounted on the following evaluation apparatus and image output was performed.

Image output device For image output, a laser beam printer “Color Laser Jet 4600” manufactured by Hewlett-Packard Co. (process speed: 100 mm / sec, dark potential: set to −700 V) was used. The charging means of this laser beam printer is a contact charging means having a charging roller, and a voltage obtained by superimposing an AC voltage on a DC voltage is applied to the charging roller. As the exposure light (image exposure light), a semiconductor laser having an oscillation wavelength of 780 nm was used so that the amount of light was variable.

Interference fringe evaluation The presence or absence of interference fringes was judged from the halftone image of the Keima pattern and the reflection spectrum of the photoreceptor. A reflection spectral film thickness meter FE-3000 manufactured by Otsuka Electronics Co., Ltd. was used for the reflection spectrum measurement.
A: No interference fringes on the image are confirmed, and no wavelength fluctuation is observed in the reflection spectrum intensity in the image exposure wavelength range. B: No interference fringes on the image are confirmed, and no wavelength fluctuation is confirmed in the reflection spectrum intensity. The
C: Although interference fringes are slightly observed on the image, there is no practical problem.
D: An image in which interference fringes are observed and is not preferable for practical use.
E: An image that is violently generated with interference fringes and is not practical.
It was. The evaluation results are shown in Table 2.

The fog and potty were evaluated from solid white images. The evaluation criteria are as follows.
A: Excellent image with no fog or spots B: Slight fog or spots, but good image.
C: fog and spots are observed D: fog and spots are greatly generated E: fog and spots are very severely generated, which is not preferable for practical use.

-Print pattern for image evaluation When performing the image evaluation described below, pre-exposure was turned off.
A ghost pattern shown in FIG. 2 was prepared as a print pattern for image evaluation. In FIG. 2, the portion 201 (black rectangle) is solid black, the portion 202 is solid white, the portion 203 is a portion where a ghost attributed to the solid black 201 may appear, and 204 is a halftone (1-dot Keima pattern). It is a part of. Magenta, cyan, yellow, and black were each produced in a single color.

Image evaluation method In an environment of 23 ° C./50% RH, evaluation was performed immediately after outputting 3000 images of 4% image density, using a ghost pattern and turning off pre-exposure.
First, a solid white image is output on the first sheet, then, five continuous ghost patterns are output. Next, after one solid black image is output, the above ghost patterns are continuously output again. 5 sheets were output. Thus, there are a total of 10 ghost patterns.
As a ghost evaluation, a spectral densitometer X-Rite 504/508 manufactured by X-Rite was used. In the image of the ghost pattern, the density obtained by subtracting the density of the halftone portion 204 from the density of the portion 203 where the ghost can appear is measured, and this measurement is performed 10 points to obtain an average value of 10 points (1 sheet) Average value). This was performed for 10 sheets, and the average value thereof was obtained (average value of 10 sheets). Further, this was performed for all four colors (magenta, cyan, yellow, and black), and an average value thereof was obtained (average value of four colors). The measurement result of each color is displayed for each of magenta, cyan, yellow, and black of the spectral densitometer X-Rite 504/508. The ghost was evaluated using the same color value as the image color as an evaluation value. The obtained results were ranked by relative evaluation when the value of the photoconductor of Comparative Example 1 was used as a reference.
A: Image with very small evaluation value and excellent uniformity B: Good image with small evaluation value.
C: Image quality with no practical problem.
D: The evaluation value is large and a ghost is observed.
E: The evaluation value is very large, and the ghost is clearly understood.

For evaluation of the reproducibility of thin lines, test charts were prepared in which alphabets (A to Z) of 2 points and 3 points and complex Chinese characters (Den, Surprise, etc.) were arranged at a resolution of 1200 dpi. The resolution of the photoconductor was evaluated by an image printed out of the test chart. Specifically, the output image was read at a resolution of 1600 dpi using a scanner (Canon Scan 9900F manufactured by Canon), and the read image data was compared with the original data of the test chart. The area of the misaligned portion (thickness, thinness) from the characters of the test document was calculated, and the resolution of the photoconductor was evaluated based on the numerical value. The obtained results were ranked by relative evaluation when the value of the photoconductor of Comparative Example 1 was used as a reference.
A: A fine image with excellent fine line reproducibility. B: A good image although fine line reproducibility and image uniformity are slightly inferior.
C: Image quality that is inferior in fine line reproducibility but has no practical problem.
D: Image with poor fine line reproducibility.

As is clear from the comparison between Table 3 and Table 4, the ten-point average roughness Rzjis of the conductive layer is 0.8 μm or less;
The intermediate layer contains an azo pigment, and the molar absorption coefficient of the azo pigment at the wavelength λ is ε, the molar concentration of the azo pigment in the intermediate layer is γ, and the film thickness of the intermediate layer is ξ γ・ Ξ ≧ 1.4
The filling;
Arithmetic mean roughness Ra of the intermediate layer surface shape is 0.06 μm or more;
In an electrophotographic apparatus having a skewness Rsk of −0.5 or more and +1.0 or less, an image with few image defects such as ghosts and black spots is maintained and fine lines are reproduced while suppressing generation of interference fringes. It can be seen that a high-performance electrophotographic apparatus can be provided.

DESCRIPTION OF SYMBOLS 1 ... Electrophotographic photoreceptor 2 ... Shaft 3 ... Contact charging means 4 ... Exposure light (image exposure light)
5 ... developing means 6 ... transfer means 7 ... cleaning means 8 ... fixing means 9 ... process cartridge 10 ... guide means P ... transfer material

Claims (7)

In an electrophotographic apparatus having an exposure means, a charging means, a developing means, a transfer means, and an electrophotographic photosensitive member using a laser light source having an oscillation wavelength λ,
The electrophotographic photosensitive member is provided with a conductive layer, an intermediate layer, a charge generation layer, and a charge transport layer in this order on a support;
The conductive layer has a ten-point average roughness Rzjis of 0.8 μm or less;
The intermediate layer contains an azo pigment, and the molar absorption coefficient of the azo pigment at the wavelength λ is ε, the molar concentration of the azo pigment in the intermediate layer is γ, and the film thickness of the intermediate layer is ξ γ・ Ξ ≧ 1.4
The filling;
An electrophotographic apparatus, wherein an arithmetic mean roughness Ra of the intermediate layer surface shape is 0.06 μm or more; and a skewness Rsk is −0.5 or more and +1.0 or less. An electrophotographic apparatus wherein the azo pigment is represented by the following general formula (1).
General formula (1)
Ck _1- (N = N-Cp) _n
(In the formula (1), Ck ₁ represents a substituted or unsubstituted aromatic hydrocarbon group or heterocyclic group which may be bonded directly or via a bonding group, and Cp is a coupler having a phenolic hydroxyl group. -Represents a residue, and at least one of Cp is a coupler residue represented by the following general formula (2), n represents an integer of 1 to 3, provided that -N = N-Cp is the same benzene ring. There is no connection to multiple
General formula (2)

(In formula (2), Y ₁ represents an aromatic hydrocarbon ring which may have a substituent by condensing with a benzene ring in the formula, or a heterocyclic ring which may have a substituent, and R ₁ and R ₂ may be the same or different and has a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, an aralkyl group which may have a substituent or a substituent. And R ₁ and R ₂ may combine to form a cyclic amino group together with the nitrogen atom in the formula, and p represents 0 or 1.) The electrophotographic apparatus according to claim 1, wherein the azo pigment is represented by the following general formula (3) or the following general formula (4).
General formula (3)

General formula (4)

(In the formulas (3) and (4), Ck ₂ and Ck ₃ represent a substituted or unsubstituted aromatic hydrocarbon group or heterocyclic group which may be bonded directly or via a bonding group, and R ₃ and R ₄ , R ₅ and R ₆ and R ₇ may be the same or different, R ₃ , R ₄ , R ₅ , R ₆ and R 7 represent an aryl group which may have a substituent, and R ₃ and R ₄ , R ₅ and R ₆ and R ₇ may be the same or different, and Y ₂ , Y ₃ , Y ₄ , Y ₅ and Y ₆ may be condensed with a benzene ring in the formula to have a substituent. An aromatic hydrocarbon ring or a heterocyclic ring which may have a substituent, q represents 1 or 2) 2. The electrophotographic apparatus according to claim 1, wherein the azo pigment has a structure represented by the following general formula (5).
General formula (5)

(In Formula (5), R ₈ and R ₉ represent an aryl group which may have a substituent, and R ₈ and R ₉ may be the same or different. X represents a halogen atom.) The electrophotographic apparatus according to claim 1, wherein the azo pigment has a structure represented by the following general formula (6).
General formula (6)

(In the formula _(6), R _{10, R 11} and _{R 12} represents an aryl group which may have a _{substituent, R 10} and _{R 11} and _{R 12} may be the same or different.)   6. The intermediate layer of an electrophotographic photosensitive member is produced using an azo pigment having a particle size of 0.4 μm to 1.0 μm as an average dispersed particle size in a coating solution. The electrophotographic apparatus according to any one of the above.   When the intermediate layer of the electrophotographic photosensitive member disperses the azo pigment, the dispersion is started using the gelled resin, and the temperature during dispersion is between 95% and 100% of the gel disappearance temperature. The electrophotographic apparatus according to claim 1, wherein the electrophotographic apparatus is manufactured.

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