JP2007017877A - Electrophotographic photoreceptor, process cartridge and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which further suppresses occurrence of ghost images even if the electrophotographic photoreceptor is obtained by disposing a conductive layer, an intermediate layer, a charge generating layer and a charge transport layer in this order on a support, and to provide a process cartridge and an electrophotographic apparatus with the electrophotographic photoreceptor. <P>SOLUTION: The electrophotographic photoreceptor has a conductive layer, an intermediate layer, a charge generating layer and a charge transport layer in this order on a support, wherein the conductive layer contains at least metal oxide particles and a binder resin. The metal oxide particles have an average particle diameter of 0.20-0.60 μm, the metal oxide particles are titanium oxide particles covered with oxygen deficient tin oxide, the conductive layer has a volume resistivity of >8.0×10<SP>8</SP>to 1.0×10<SP>11</SP>Ω cm, and the charge generating layer contains a phenol compound. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member, a process cartridge having an electrophotographic photosensitive member, and an electrophotographic apparatus.

  In general, an electrophotographic photoreceptor (organic electrophotographic photoreceptor) is composed of a support and a photosensitive layer provided 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 covering property, adhesiveness, mechanical strength, electrical conductivity, and electrical barrier property.

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 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) In order to prevent charge injection from the substrate (ii) above to the photosensitive layer, which causes image defects, in a wide range of environmental conditions from low temperature and low humidity to high temperature and high humidity. It is preferable that a layer having an electrical barrier property is separately provided 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 (undercoat 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 have good dimensional accuracy as a non-cutting tube without surface cutting. It is used as a support for an electrophotographic photosensitive member that provides surface smoothness and is advantageous in terms of cost, but the surface of these uncut aluminum tubes tends to have a sacrificial convex defect, From the viewpoint of hiding the surface defects of the support, the configuration (iii) is preferable.

Examples of the conductive material used for the conductive layer include various metals, metal oxides, and conductive polymers. Among these, tin oxide (hereinafter referred to as SnO ₂ ) having excellent resistance characteristics can be used in the production of SnO ₂ conductive materials, such as antimony oxide, from the ordinary powder resistivity of 10 ⁴ to 10 ⁶ Ω · cm. Mixing (doping) a metal compound or a nonmetallic element having a valence different from that of tin, reducing the powder resistivity to 1/1000 to 1/100000, or non-doping without increasing the constituent elements Thus, there is an oxygen-deficient SnO ₂ conductive material in which 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, JP 07-295245 A (Patent Document 1) discloses a technique using oxygen deficient SnO ₂ for a conductive layer. Japanese Patent Laid-Open No. 208238 (Patent Document 2) discloses a technique for improving dispersibility as compared with the case where only barium sulfate particles are coated with oxygen-deficient SnO ₂ and only SnO ₂ is used. In order to improve the dispersibility, barium sulfate particles are used to improve the whiteness degree, although the publication (Patent Document 3) does not disclose the embodiment of oxygen-deficient SnO _2. In addition, a technique of coating SnO ₂ is disclosed in order to coat titanium oxide (TiO ₂ ) and to provide conductivity on the titanium oxide (TiO ₂ ).

  By the way, in recent years, the charging uniformity of the charging device has been improved, and the need for pre-charging static elimination means (such as a pre-exposure device) to prevent charging unevenness from appearing in the output image has been diminished, saving space. Further, from the viewpoint of cost reduction, there is an increasing need for an electrophotographic apparatus having a configuration in which this is omitted.

  However, when the pre-charging neutralization means such as the pre-exposure device is omitted, the ghost image of the rotation cycle of the electrophotographic photosensitive member (on the halftone image, the exposure history of the electrophotographic photosensitive member one rotation before (solid black image, etc.) The phenomenon that appears) becomes prominent.

  This ghost phenomenon is thought to be partly due to the stagnation of charge (carrier) flow when an electrostatic latent image is formed on an electrophotographic photosensitive member. In a configuration with a conductive layer, there is no conductive layer. Since the number of layers is larger than that, the flow of electric charges (carriers) tends to stagnate accordingly.

  Until now, the ghost phenomenon could be almost eliminated by providing a pre-charge neutralization means such as a pre-exposure device to uniformly reduce the surface potential of the electrophotographic photosensitive member before charging. It was rarely highlighted as a technical issue. That is, a ghost phenomenon occurs remarkably in the case where there is no pre-charging neutralizing means such as a pre-exposure device.

As a prior art for improving such a ghost phenomenon by the configuration of the conductive layer, Japanese Patent Application Laid-Open No. 07-271072 (Patent Document 4) discloses SnO _{2 in} which the powder resistivity is reduced by doping the above-described antimony oxide. A technique used as a conductive material coated with TiO ₂ particles is disclosed. Furthermore, in place of the antimony-doped conductive material having poor reusability, Japanese Patent Laid-Open No. 2005-107177 (Patent Document 5) uses conductive particles obtained by coating the above-described oxygen-deficient SnO ₂ with TiO _2. In addition to improving the reusability, a technique is disclosed in which the volume resistance of the conductive layer is controlled to be lower to smooth the flow of electric charges (carriers) in the conductive layer.
JP 07-295245 A Japanese Patent Laid-Open No. 06-208238 JP-A-10-186702 Japanese Patent Application Laid-Open No. 07-271072 JP-A-2005-107177

However, when the volume resistivity of the conductive layer is controlled to 5.0 × 10 ^{5 to} 8.0 × 10 ⁸ Ω · cm as disclosed in Patent Document 5, the occurrence of the ghost phenomenon is suppressed. However, when the volume resistivity of the conductive layer exceeds 8.0 × 10 ⁸ Ω · cm and is 1.0 × 10 ¹¹ Ω · cm or less, a ghost phenomenon occurs.

The object of the present invention is to cover defects on the surface of the support, improve the coatability of the photosensitive layer, improve the adhesion between the support and the photosensitive layer, protect against electrical breakdown of the photosensitive layer, improve the charging property, An electrophotographic photosensitive member in which a conductive layer, an intermediate layer, a charge generation layer, and a charge transport layer are provided on a support in this order in order to improve charge injection into the photosensitive layer, and the volume of the conductive layer Even if the resistivity exceeds 8.0 × 10 ⁸ Ω · cm and is 1.0 × 10 ¹¹ Ω · cm or less, an electrophotographic photosensitive member in which the occurrence of the ghost phenomenon is suppressed can be obtained by using oxygen having excellent reusability. It is to provide using deficient SnO2.

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

The present invention is an electrophotographic photosensitive member in which a conductive layer, an intermediate layer, a charge generation layer, and a charge transport layer are provided in this order on a support, and the conductive layer contains a binder resin and conductive particles In an electrophotographic photoreceptor
The conductive particles are TiO ₂ particles coated with oxygen-deficient SnO ₂ ;
The average particle diameter of the conductive particles is 0.20 to 0.60 μm,
The electrophotographic photosensitive material, wherein the conductive layer has a volume resistivity of more than 8.0 × 10 ⁸ Ω · cm and not more than 1.0 × 10 ¹¹ Ω · cm, and the charge generation layer contains a phenol compound. Is the body.

  The present invention also provides a toner image by developing the electrophotographic photosensitive member, charging means for charging the surface of the electrophotographic photosensitive member, and developing an electrostatic latent image on the surface of the electrophotographic photosensitive member with toner. A developing means for transferring, a transferring means for transferring a toner image on the surface of the electrophotographic photosensitive member to a transfer material, and a cleaning means for cleaning the toner remaining on the surface of the electrophotographic photosensitive member after transfer It is a process cartridge characterized in that it supports at least one means selected as a unit and is detachable from the main body of the electrophotographic apparatus.

  The present invention also provides the above-described electrophotographic photosensitive member, charging means for charging the surface of the electrophotographic photosensitive member, and forming an electrostatic latent image on the surface of the electrophotographic photosensitive member charged by the charging means by exposure. Exposure means for developing, developing means for developing an electrostatic latent image on the surface of the electrophotographic photosensitive member formed by the exposure means with toner to form a toner image, and electrophotography formed by the developing means An electrophotographic apparatus comprising transfer means for transferring a toner image on the surface of a photoreceptor to a transfer material.

According to the present invention, coating of defects on the surface of the support, improvement in coating properties of the photosensitive layer, improvement in adhesion between the support and the photosensitive layer, protection against electrical breakdown of the photosensitive layer, improvement in chargeability, An electrophotographic photosensitive member in which a conductive layer, an intermediate layer, a charge generation layer, and a charge transport layer are provided on a support in this order in order to improve charge injection into the photosensitive layer, and the volume of the conductive layer Even if the resistivity exceeds 8.0 × 10 ⁸ Ω · cm and is 1.0 × 10 ¹¹ Ω · cm or less, an electrophotographic photosensitive member in which the occurrence of the ghost phenomenon is suppressed can be obtained by using oxygen having excellent reusability. It can be provided using deficient SnO ₂ .

  Further, according to the present invention, a process cartridge and an electrophotographic apparatus having such an electrophotographic photosensitive member can be provided.

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

  As described above, the electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member in which a conductive layer, an intermediate layer, a charge generation layer, and a charge transport layer are provided in this order on a support.

  In the present invention, the charge generation layer contains a phenol compound. Although a reducing substance can be used as the phenol compound, a compound represented by the following general formula (1) or general formula (2) is particularly preferable.

（式中、Ｒ_１、Ｒ_２、Ｒ_４及びＲ_５は同一でも異なっていてもよく、置換されてもよいアルキル基、アリール基、アラルキル基、アルケニル基、アルコキシ基またはアシル基の中から選ばれる。Ｒ_３は水素原子、ハロゲン原子、炭素数１〜２０であり、且つ置換されてもよいアルキル基、アリール基、アラルキル基、アルケニル基、アルコキシ基またはアシル基の中から選ばれる。Ｘは置換基を有しても良い２価のアルキレン基、炭素−炭素結合間に酸素原子を介しても良い２価のアルキレン基を示す。ｎは２〜４の整数を示す。Ｙは水素原子を有してもよい炭素原子または硫黄原子を示す。ただし、ｎが２のとき、Ｙは単結合であってもよい。

(Wherein R ₁ , R ₂ , R ₄ and R ₅ may be the same or different and are selected from an optionally substituted alkyl group, aryl group, aralkyl group, alkenyl group, alkoxy group or acyl group) R ₃ is selected from a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, and an optionally substituted alkyl group, aryl group, aralkyl group, alkenyl group, alkoxy group or acyl group. A divalent alkylene group which may have a substituent, a divalent alkylene group which may have an oxygen atom interposed between carbon-carbon bonds, n represents an integer of 2 to 4. Y represents a hydrogen atom. A carbon atom or a sulfur atom which may be present, provided that when n is 2, Y may be a single bond.

  The phenol compound used in the present invention may be used alone or in combination of two or more.

  The content of the phenol compound in the charge generation layer is preferably in the range of 2.5 to 6.8 in terms of the mass ratio G / F of the phenol compound (F) and the charge generation material (G). If it is less than 2.5, the stability of the charge generation layer coating solution becomes poor, or the residual potential increases. If it exceeds 6.8, a sufficient suppression effect on the occurrence of the ghost phenomenon cannot be obtained.

  The phenolic compound of the present invention inherently protects the charge generation material in the charge generation layer to maintain the charge generation rate, and suppresses charge injection to the charge transport layer by the deteriorated charge generation material to charge the photoreceptor. It is known to have a function of suppressing a potential drop. However, the volume resistance of the conductive layer is higher than before, and the phenol compound contained in the charge generation layer has an effect of suppressing the ghost phenomenon against the ghost phenomenon that occurs when the flow of charges (carriers) is stagnant. An unexpected effect was found and the present invention was achieved.

  Examples of phenolic compounds that can be used in the present invention are shown below, but are not limited thereto.

  The conductive layer of the present invention contains a binder resin and conductive particles.

Further, in the present invention, as the conductive particles, it was used TiO ₂ particles coated with SnO ₂ which attained low resistance (in powder resistivity 1/10000) by deficiency of oxygen. 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 particles used in the present invention are not particles composed only of oxygen-deficient SnO ₂ but TiO ₂ particles coated with oxygen-deficient SnO ₂ is as follows.

First, the core particles are used in order to improve the dispersibility of the conductive particles in the conductive layer. When a conductive layer coating solution is prepared using only oxygen-deficient SnO ₂ as the conductive particles, especially when the content ratio of oxygen-deficient SnO ₂ is high, aggregation of oxygen-deficient SnO ₂ is likely to occur.

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 This is because the oxygen deficient sites of oxygen deficient SnO ₂ are protected. The oxygen deficient type is different from the doped type in order to prevent the oxidation in the presence of oxygen, the oxygen deficient site disappears, and the conductivity may decrease (the powder resistivity increases).

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-defective TiO ₂ particle production method of the SnO ₂ coated is, JP-A 07-295245 JP And Japanese Patent Laid-Open No. 04-154621.
Further, in the present invention, when TiO ₂ particles coated with oxygen-deficient SnO ₂ are used as conductive particles containing the conductive layer, the volume resistivity of the conductive layer exceeds 8.0 × 10 ⁸ Ω · cm. Although the occurrence of the ghost phenomenon can be suppressed even when the particle size is 0.0 × 10 ¹¹ Ω · cm or less, the average particle size of the conductive particles needs to be 0.20 to 0.60 μm. In that case, it is preferable that the ratio of the particle | grains of 0.10-0.40 micrometers on a particle size distribution is 60% or more of all the particles.

  First, the volume resistivity of the conductive layer will be described.

In general, the ghost phenomenon is considered to be caused by a delay in the flow of electric charges (carriers) when an electrostatic latent image is formed on an electrophotographic photosensitive member. Therefore, the resistance of the conductive layer is preferably low. In the present invention, the volume resistivity of the conductive layer that can suppress the occurrence of the ghost phenomenon is 1.0 × 10 ¹¹ Ω · cm or less. When the volume resistivity exceeds 1.0 × 10 ¹¹ Ω · cm, the effect of suppressing the occurrence of the ghost phenomenon by the phenol compound contained in the charge generation layer cannot be sufficiently obtained. On the other hand, when the volume resistivity of the conductive layer is 8.0 × 10 ⁸ Ω · cm or less, the ghost phenomenon is generated by the technique disclosed in Patent Document 5 even if the charge generation layer does not contain a phenol compound. Can be suppressed.

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

  First, a conductive layer to be measured is formed on an aluminum sheet with a film thickness of about 10 to 15 μm, and a gold thin film is formed on the conductive layer by vapor deposition, so that a gap between both electrodes of the aluminum sheet and the gold thin film is formed. The flowing current value was measured with a pA meter. The measurement environment is 23 ° C. and 60 RH%, and the applied voltage is 0.1V. A stable value 1 minute after the start of current value measurement was read, and the volume resistivity of the conductive layer was derived.

In order to keep the volume resistivity of the conductive layer within the above range, the powder resistivity of the TiO ₂ particles coated with oxygen-deficient SnO ₂ that is conductive particles is preferably 0.01 to 500 Ω · cm. In particular, it is more preferably 1 to 250 Ω · cm. If the powder resistivity is too high, it is difficult to keep the volume resistivity of the conductive layer within the above range, while if the powder resistivity is too low, the charging ability may be lowered.

In order to stably obtain TiO ₂ particles coated with oxygen-deficient SnO ₂ having a powder resistivity in the above range, the raw material blending ratio in producing the particles may be controlled. For example, to calculate the SnO ₂ and 100% tin raw material is obtained, the tin raw material necessary to produce the oxygen-deficient SnO ₂ of SnO ₂ with respect to TiO ₂ coated with 30 to 80 wt% What is necessary is just to mix | blend at the time of particle | grain manufacture. In other words, the coverage of oxygen-deficient SnO _{2 on} TiO ₂ is preferably 30 to 80% by mass.

  The measurement method of the powder resistivity in the present invention is as follows.

As a measuring device, a resistance measuring device Loresta AP (Loresta Ap) manufactured by Mitsubishi Chemical Corporation was used. The powder to be measured (= particles) was hardened at a pressure of 500 kg / cm ² to obtain a pellet-shaped measurement sample. The measurement environment is 23 ° C. and 60% RH, and the applied voltage is 100V.

Next, the average particle diameter of TiO ₂ particles coated with oxygen-deficient SnO ₂ that is conductive particles will be described.

  Even if the composition of the conductive layer is the same, the powder resistivity of the conductive particles decreases as the average particle size of the conductive particles increases, and the volume resistivity of the conductive layer also decreases.

When the average particle diameter of the TiO ₂ particles coated with oxygen-deficient SnO ₂ that is conductive particles is less than 0.20 μm, the amount of the conductive particles used is increased in order to keep the volume resistivity of the conductive layer within the above range. Although it is necessary, when the amount of the conductive particles used is increased, the surface roughness of the conductive layer suitable for suppressing the interference of light reflected on the surface of the conductive layer and generating interference fringes in the output image ( Rzjis: 1.0 to 3.0 μm) is difficult to achieve. 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. Furthermore, when the amount of the conductive particles used is increased, not only the generation of interference fringes but also the increase in the thickness of the conductive layer tends to cause cracks, which may reduce the film formability.

On the other hand, when the average particle diameter of the TiO ₂ particles coated with oxygen-deficient SnO ₂ that is conductive particles exceeds 0.60 μm, the volume resistivity of the conductive layer can fall within the above range. The surface becomes extremely rough, local charge injection into the photosensitive layer is likely to occur, and spots on white background in the output image become conspicuous. In addition, the effect of suppressing the ghost phenomenon is reduced.

  The method for measuring the average particle size and particle size distribution in the present invention is as follows.

  Dispersion particles were measured by a liquid phase precipitation method using a conductive layer coating solution having a composition of only conductive particles. Specifically, the conductive layer coating solution was diluted with the solvent used therein, and the average particle size and particle size distribution were measured using an ultracentrifugal automatic particle size distribution analyzer (CAPA700) manufactured by Horiba, Ltd. .

In the present invention, the conductive layer is a conductive layer coating solution obtained by dispersing TiO ₂ particles coated with oxygen-deficient SnO ₂ having an average particle size of 0.20 to 0.60 μm together with a binder resin and a solvent. It can be formed by coating on top and drying it. 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.

Solvents used in the coating liquid for the conductive layer include 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.
The film thickness of the conductive layer is preferably 0.1 to 15 μm from the viewpoint of suppressing the occurrence of the ghost phenomenon, but the film thickness of the conductive layer is 15 to 25 μm in order to reliably hide the surface defects of the support. However, the occurrence of the ghost phenomenon can be suppressed in the present invention.

  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 resin for the conductive layer include phenol resin, polyurethane resin, polyamide resin, polyimide resin, polyamideimide resin, polyamic acid resin, polyvinyl acetal resin, epoxy resin, acrylic resin, melamine resin, and polyester resin. 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 conductive particles, 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, a polyurethane resin, or the like is preferable.

Further, the mass ratio (P / B) between the TiO ₂ particles coated with oxygen-deficient SnO ₂ having an average particle diameter of 0.20 to 0.60 μm, which is the conductive particles (P), and the binder resin (B) is: 2.3 to 3.3. It is disclosed in Reference 5 that the volume resistivity of the conductive layer can be controlled to be low and the occurrence of the ghost phenomenon can be suppressed in the range where P / B is as large as 3.5 to 6.0. If P / B is too small than 2.3, it is difficult to keep the volume resistivity of the conductive layer in the above range. If P / B is too large than 6.0, the average particle diameter in the conductive layer is 0.20. It becomes difficult to bind TiO ₂ particles coated with oxygen-deficient SnO ₂ of ˜0.60 μm.

Further, in order to suppress the interference of light reflected on the surface of the conductive layer and the generation of interference fringes in the output image, the conductive layer is provided with a binder resin and an oxygen-deficient type having an average particle size of 0.20 to 0.60 μm. In addition to the TiO ₂ particles coated with SnO ₂ , it is also possible to add a surface roughening agent for roughening the surface of the conductive layer. As the surface roughness imparting material, resin particles having an average particle diameter of 1 to 3 μm are preferable, and examples thereof include curable rubber, polyurethane resin, epoxy resin, alkyd resin, phenol resin, polyester resin, silicone resin, and acrylic-melamine resin. Examples include curable resin particles. 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 TiO ₂ particles coated with oxygen-deficient SnO ₂ , the surface of the conductive layer is efficiently formed when the conductive layer is formed. It can be roughened. However, since the volume resistivity of the conductive layer tends to increase as the content of the surface roughening agent in the conductive layer increases, in order to keep the volume resistivity of the conductive layer within the above range, The content of the surface roughening agent is preferably 15 to 35% by mass with respect to the binder resin in the conductive layer.

  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 to} 1.0 × 10 ¹³ Ω · cm. 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 to be measured is formed on an aluminum sheet with a film thickness of about 2 to 5 μm, and a thin gold film is formed on the intermediate layer by vapor deposition. The flowing current value was measured with a pA meter. The measurement environment is RH%, and the applied voltage is 100V. A stable value one minute after the start of the current value measurement was read and used as the volume resistivity of the intermediate layer.

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

  As the binder resin for the intermediate layer, water-soluble resins such as polyvinyl alcohol, polyvinyl methyl ether, polyacrylic acid, methyl cellulose, ethyl cellulose, polyglutamic acid, casein, and starch, polyamide resin, polyimide resin, polyamideimide resin, and polyamic acid resin , Melamine resin, epoxy resin, polyurethane resin, polyglutamate resin and the like. In order to effectively develop the electrical barrier property, 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 resin or the like is preferable. The polyamide resin 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 0.1-2 micrometers.

  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 photosensitive member 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) on a support 101 in this order. Is the body.

  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. A multilayer (functional separation type) photosensitive layer separated into a charge transport layer 1042 containing a substance may be used, but a multilayer photosensitive layer is preferred from the viewpoint of electrophotographic characteristics. 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. Although there is a reverse type photosensitive layer (see FIG. 1C) in which 1042 and the charge generation layer 1041 are laminated in this order, the normal type photosensitive layer is preferable from the viewpoint of electrophotographic characteristics.

  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 the support, one having conductivity (support) is preferable, and for example, a support made of metal such as aluminum, aluminum alloy, and stainless steel can be used. In the case of aluminum and an aluminum alloy, an aluminum tube manufactured by a manufacturing method including an extrusion step and a drawing step, an aluminum tube manufactured by a manufacturing method including an extrusion step and a squeezing step, and cutting and electrolytic composite polishing ( An electrode having an electrolytic action and electrolysis with an electrolytic solution and polishing with a grindstone having a polishing action), wet or dry honing treatment can also 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 conductive particles such as carbon black, tin oxide particles, titanium oxide particles, and silver particles are impregnated with a 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 preferably 1.0 × 10 ¹⁰ Ω · cm or less. Further, even when the surface of the support has a layer provided for imparting conductivity, the volume resistivity of the layer is preferably 1.0 × 10 ¹⁰ Ω · cm or less.

  When the support is a non-conductive support, it is necessary to adopt a configuration in which the ground is taken from the conductive layer of the electrophotographic photosensitive member of the present invention.

  A conductive layer is provided on the 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 photoreceptor of the present invention include azo pigments such as monoazo, disazo, and trisazo, phthalocyanine pigments such as metal phthalocyanine and nonmetal 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 dyes, pyrylium salts and thiapyrylium salts, triphenylmethane dyes, selenium, selenium-tellurium, amorphous Examples thereof include inorganic substances such as silicon, quinacridone pigments, azulenium salt pigments, cyanine dyes, xanthene dyes, quinoneimine dyes, styryl dyes, cadmium sulfide, and zinc oxide. 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 polycarbonate resin, polyester resin, polyarylate resin, butyral resin, polystyrene resin, polyvinyl acetal resin, diallyl phthalate resin, and acrylic resin. Methacrylic resin, vinyl acetate resin, phenol resin, silicone resin, polysulfone resin, styrene-butadiene copolymer resin, alkyd resin, epoxy resin, urea resin, vinyl chloride-vinyl acetate copolymer resin, and the like. These can be used singly or in combination of two or more 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, a phenol compound 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 (mass ratio), and more preferably in the range of 3: 1 to 1: 1 (mass ratio).

  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 and aromatic compounds.

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

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

  In addition, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers, and the like can be added to the charge generation layer as necessary. Further, in order to prevent the flow of electric charges (carriers) in the charge generation layer, the charge generation layer may contain an electron transport material (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 acrylic resin, styrene resin, polyester resin, polycarbonate resin, polyarylate resin, polysulfone resin, polyphenylene oxide resin, epoxy resin, Examples include polyurethane resins, alkyd resins, and unsaturated resins. In particular, polymethyl methacrylate resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polycarbonate resin, polyarylate resin, diallyl phthalate resin and the like are preferable. These can be used singly or in combination of two or more 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 between the charge transport material and the binder resin is preferably in the range of 2: 1 to 1: 2 (mass ratio).

  Solvents used in the charge transport layer coating solution include 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, chlorobenzene and chloroform. In addition, a hydrocarbon substituted with a halogen atom such as carbon tetrachloride is used.

  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 thickness of the charge transport layer is preferably 5 to 40 μm, and more preferably 10 to 30 μm from the viewpoint of charging uniformity and electric field strength.

  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 0.5 to 10 μm, and particularly preferably 1 to 5 μm.

  FIG. 2 shows an example of a schematic configuration of an electrophotographic apparatus provided with the process cartridge of the present invention.

  In FIG. 2, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member, which is driven to rotate at a predetermined peripheral speed in the direction of the arrow about the shaft 2.

  The peripheral surface of the electrophotographic photosensitive member 1 that is driven to rotate is uniformly charged to a predetermined positive or negative potential by the charging unit 3, and then output from an exposure unit (not shown) such as slit exposure or laser beam scanning exposure. The exposure light (image exposure light) 4 is received. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the peripheral surface of the electrophotographic photosensitive member 1. The voltage applied to the charging unit 3 may be only a DC voltage or a DC voltage on which an AC voltage is superimposed.

  The electrostatic latent image formed on the peripheral surface of the electrophotographic photosensitive member 1 is developed with toner of the developing unit 5 to become a toner image. Next, the toner image formed and supported on the peripheral surface of the electrophotographic photosensitive member 1 is transferred from the transfer material supply unit (not shown) by the transfer bias from the transfer unit (transfer roller) 6 to the electrophotographic photosensitive member 1 and the transfer unit. 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 peripheral surface of the electrophotographic photosensitive member 1 and is introduced into the fixing means 8 to undergo image fixing, and is printed out of the apparatus as an image formed product (print, copy). Be out.

  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 the charge removal process by the pre-exposure light 11, it is repeatedly used for image formation. As shown in FIG. 2, when the charging unit 3 is a contact charging unit using a contact charging member such as a charging roller, the configuration is formed on, for example, a conductive support and on the outer periphery thereof. And a surface layer formed thereon (outer periphery). In addition, the surface roughness of the charging roller is preferably 5 μm or less from the viewpoint of suppressing image unevenness due to contamination of the charging roller due to adhesion of toner, toner external additives, and paper powder during continuous paper feeding.

As the transfer means, for example, an intermediate transfer type transfer means using an intermediate transfer body such as a belt shape or a drum shape may be employed. When a belt-shaped intermediate transfer member (intermediate transfer belt) is used, the volume resistivity is preferably 1.0 × 10 ^{6 to} 8.0 × 10 ¹³ Ω · cm.

  Among the above-described components such as the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5, the transfer unit 6 and the cleaning unit 7, a plurality of components are housed in a container and integrally combined as a process cartridge. The process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. In FIG. 2, the electrophotographic photosensitive member 1, the contact charging means 3, the developing means 5 and the cleaning means 7 are integrally supported to form a cartridge, and electrophotographic using a guide means 10 such as a rail of the 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 1
An aluminum cylinder (JIS-A3003, aluminum alloy) having a length of 260.5 mm and a diameter of 30 mm manufactured by an extrusion / pulling process was used as a support. The Rzjis of this support was measured and found to be 0.8 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.
Next, TiO ₂ particles coated with oxygen-deficient SnO ₂ as conductive particles (powder resistivity 400 Ω · cm, SnO ₂ coverage (mass ratio) 50%) 7.41 parts, as binder resin Phenol resin (trade name: J-325, manufactured by Dainippon Ink & Chemicals, Inc., resin solid content 60%) 4.12 parts, 8.60 parts of methoxypropanol as a solvent, 1 mm diameter glass beads used The dispersion was prepared by dispersing for 3 hours in a sand mill.

The average particle diameter of the TiO ₂ particles coated with oxygen-deficient SnO ₂ in this dispersion was 0.20 μm.

  In this dispersion, 0.5 parts of silicone resin particles (trade name: Tospearl 120, manufactured by GE Toshiba Silicone Co., Ltd., average particle diameter 2 μm) as a surface roughness imparting agent, silicone oil (trade name: product name: 0.001 part of SH28PA (Toray Dow Corning Silicone Co., Ltd.) was added and stirred to prepare a conductive layer coating solution.

  This conductive layer coating solution is dip-coated on a support in an environment of 23 ° C. and 60% RH, and dried and thermally cured at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 4 μm. did. When Rzjis on the surface of the conductive layer was measured, it was 0.9 μm.

Separately, this conductive layer coating solution was applied to an aluminum sheet with a Meyer bar to a thickness of 4 μm and dried to prepare a conductive layer volume resistivity measurement sample. A gold thin film was formed on the conductive layer by vapor deposition, and the volume resistivity of the conductive layer was measured and found to be 1.0 × 10 ⁹ Ω · cm.

  Next, on the conductive layer, 4 parts of N-methoxymethylated nylon (trade name: Toresin EF-30T, manufactured by Teikoku Chemical Industry Co., Ltd.) and 2 parts of copolymer nylon resin (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, whereby the film thickness is 0.5 μm. An intermediate layer was formed.

Separately, this intermediate layer coating solution was applied onto an aluminum sheet with a Meyer bar to a thickness of 3 μm and dried to prepare a sample for measuring the volume resistivity of the intermediate layer. A gold thin film was formed on the intermediate layer by vapor deposition, and the volume resistivity of the intermediate layer was measured and found to be 5.0 × 10 ¹¹ Ω · cm.

  Next, the Bragg angles (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction are 7.5 °, 9.9 °, 16.3 °, 18.6 °, 25.1 °, and 28.3 °. 10 parts of a crystalline form of hydroxygallium phthalocyanine having a strong peak, 5 parts of polyvinyl butyral (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.), 2 parts of a phenolic compound represented by F-8 in Table 1 and cyclohexanone 250 parts were dispersed in a sand mill 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 of dimethoxymethane / 70 parts of 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 17 μm.

  In this manner, an electrophotographic photoreceptor having a charge transport layer as a surface layer was produced.

  The prepared electrophotographic photosensitive member is mounted on a laser beam printer LBP-2510 manufactured by Canon Inc. in a state where the power of the pre-exposure unit is turned off in an environment of 15 ° C. and 10% RH. The image after endurance of the sheet was evaluated. Details are as follows.

  The produced electrophotographic photosensitive member was mounted on a cyan process cartridge of LBP-2510, and mounted on a cyan process cartridge station for evaluation.

  At the time of paper passing, a full color printing operation was performed in an intermittent mode in which a character image with a printing rate of 2% for each color was output on a letter paper every 20 seconds, and 4000 images were output.

  Three samples (solid white, ghost chart, solid black, and halftone image of Keima pattern) for image evaluation were output at the start of evaluation and at the end of 4000.

  Note that the ghost chart is a print image writing position in which a range of 30 mm from the print image writing position (upper edge of paper 10 mm) is placed on a solid white background with 25 mm square solid black squares arranged at equal intervals and parallel to the print image writing position. The chart after 30 mm from the position is a chart for printing a halftone of a Keima pattern (a halftone image in which a Shogi Keima pattern (a pattern in which 2 dots are printed on 6 squares) is repeated).

The ghost evaluation results were classified from the ghost chart as follows.
A: no ghost, B: almost no ghost, C: ghost is slightly observed, D: ghost is observed, E: ghost is clearly seen.

The presence or absence of interference fringes was classified as follows from the halftone image of the Keima pattern.
A: There are no interference fringes, B: Some interference fringes are observed, and C: Interference fringes are observed.

  The fog and potty were evaluated from solid white images. If there is no occurrence of fog or spots, nothing is stated.

  In addition, after outputting a sample for image evaluation, an apparatus for measuring the surface potential of the electrophotographic photosensitive member (an apparatus in which a probe for measuring the surface potential of the electrophotographic photosensitive member is installed at the developing roller position of the process cartridge (toner, The developing roller and the cleaning blade were removed), and the ghost potential was measured with the electrophotographic photosensitive member mounted and the electrostatic transfer belt unit of LBP-2510 removed.

  The method for measuring the ghost potential is as follows.

  First, letter paper size ghost potential measurement chart (in the range of 25 mm from the print image writing (upper edge 10 mm) position is solid black, the range of 25-30 mm from the print image writing position is solid white, from the print image writing position After 30 mm, the surface potential of the electrophotographic photosensitive member was measured at a cyan process cartridge station in a non-sheet-passing printing mode (repetition of Keiton pattern halftone).

  Next, the difference between the halftone potential after one rotation of solid black and the halftone potential before and after that (the halftone potential after one rotation of solid black is smaller than the halftone potential immediately before and after one rotation of solid black) is the ghost potential. It was.

  The results are shown in Table 1.

(Examples 2 to 7)
In Example 1, electrons were changed in the same manner as in Example 1 except that the phenol compound in the charge generation layer was changed to F-3, F-9, F-11, F-12, F-15, and F-17, respectively. Photoconductors were prepared and evaluated. The results are shown in Table 1.

(Example 8)
In Example 1, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the following points were changed. The results are shown in Table 1.

The amount of TiO ₂ particles coated with oxygen-deficient SnO ₂ that is conductive particles of the conductive layer was changed to 6.89 parts, and the amount of phenol resin that is the binder resin of the conductive layer was changed to 4.98 parts. . As a result, Rzjis on the surface of the conductive layer was 0.7 μm, and the volume resistivity of the conductive layer was 8.4 × 10 ¹⁰ Ω · cm.

Example 9
In Example 1, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the following points were changed. The results are shown in Table 1.

The amount of TiO ₂ particles coated with oxygen-deficient SnO ₂ that is conductive particles of the conductive layer was changed to 7.82 parts, and the amount of phenol resin that is the binder resin of the conductive layer was changed to 3.42 parts. . As a result, Rzjis on the surface of the conductive layer was 1.2 μm, and the volume resistivity of the conductive layer was 8.6 × 10 ⁸ Ω · cm.

(Example 10)
In Example 8, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 8 except that the following points were changed. The results are shown in Table 1.

The powder resistivity of the conductive particles of the conductive layer was set to 35 Ω · cm, and the coverage (mass ratio) of SnO ₂ was changed to 76%. The average particle diameter of the TiO ₂ particles coated with this oxygen-deficient SnO ₂ was 0.57 μm. As a result, Rzjis on the surface of the conductive layer was 1.6 μm, and the volume resistivity of the conductive layer was 8.2 × 10 ⁸ Ω · cm.

(Example 11)
In Example 8, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 8 except that the following points were changed. The results are shown in Table 1.

The powder resistivity of the conductive particles of the conductive layer was changed to 75 Ω · cm, and the coverage (mass ratio) of SnO ₂ was changed to 58%. The average particle diameter of the TiO ₂ particles coated with the oxygen-deficient SnO ₂ was 0.47 μm. As a result, Rzjis on the surface of the conductive layer was 1.4 μm, and the volume resistivity of the conductive layer was 4.5 × 10 ⁹ Ω · cm.

(Example 12)
In Example 11, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 11 except that the amount of the phenol compound used in the charge generation layer was changed to 4.00 parts. The results are shown in Table 1.

(Example 13)
In Example 11, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 11 except that the amount of the phenol compound used in the charge generation layer was changed to 1.47 parts. The results are shown in Table 1.

(Example 14)
In Example 12, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 12 except that the phenol compound in the charge generation layer was changed to F-11. The results are shown in Table 1.

(Example 15)
In Example 13, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 13 except that the phenol compound in the charge generation layer was changed to F-11. The results are shown in Table 1.

(Example 16)
In Example 14, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 14 except that the thickness of the conductive layer was changed to 9 μm and the amount of the phenol compound used in the charge generation layer was changed to 2.00 parts. did. The results are shown in Table 1.
As a result, Rzjis on the surface of the conductive layer was 1.5 μm.

(Example 17)
In Example 14, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 14 except that the film thickness of the conductive layer was changed to 10 μm. The results are shown in Table 1.
As a result, Rzjis on the surface of the conductive layer was 1.6 μm.

(Example 18)
In Example 14, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 14 except that the thickness of the conductive layer was changed to 19 μm. The results are shown in Table 1.
As a result, Rzjis on the surface of the conductive layer was 2 μm.

Example 19
In Example 14, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 14 except that the film thickness of the conductive layer was changed to 25 μm. The results are shown in Table 1.
As a result, Rzjis on the surface of the conductive layer was 2.3 μm.

(Example 20)
In Example 11, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 11 except that the following points were changed. The results are shown in Table 1.

First, the support was changed to a JIS-A3003 aluminum cylinder subjected to wet honing treatment under the following conditions. For the honing process, a wet honing apparatus manufactured by Fuji Seiki Co., Ltd. was used. As a result, the surface Rzjis was 2.0 μm.
-Honing conditions-
Abrasive abrasive grains: spherical alumina beads having an average particle diameter of 30 μm (trade name: CB-A30S, manufactured by Showa Denko KK)
Suspension medium: water abrasive grains / suspension medium = 1/9 (volume ratio)
Number of rotations of aluminum cylinder: 1.67 s ⁻¹
Air blowing pressure: 0.165 MPa
Gun moving speed: 13.3 mm / s
Distance between gun nozzle and aluminum cylinder: 180mm
Abrasive abrasive particle discharge angle: 45 °
Polishing liquid (abrasive abrasive grains and suspension medium): Number of times of projection: once The film thickness of the conductive layer was changed to 2 μm. As a result, Rzjis on the surface of the conductive layer was 1.8 μm.

(Comparative Example 1)
In Example 1, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that no phenol compound was used in the charge generation layer. The results are shown in Table 1.

(Comparative Example 2)
In Example 1, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the following points were changed. The results are shown in Table 1.

The amount of barium sulfate particles (powder resistivity: 950 Ω · cm, SnO ₂ coverage (mass ratio): 32%) coated with oxygen-deficient SnO ₂ as the conductive particles of the conductive layer is 7.90 parts. The amount of phenol resin used as the binder resin for the conductive layer was changed to 3.30 parts, and the film thickness of the conductive layer was changed to 6 μm. The average particle diameter of the barium sulfate particles coated with the oxygen-deficient SnO ₂ was 0.19 μm. As a result, Rzjis on the surface of the conductive layer was 0.85 μm, and the volume resistivity of the conductive layer was 6.0 × 10 ⁸ Ω · cm. In addition, no phenolic compound was used in the charge generation layer.

(Comparative Example 3)
In Example 1, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the following points were changed. The results are shown in Table 1.
Conductive layer of a conductive particle 10 wt% of antimony oxide-doped SnO ₂ The coated TiO2 particles the amount of (powder resistivity of 10 [Omega · cm, coverage of SnO ₂ (mass ratio) 50%) The amount of phenol resin used as the binder resin for the conductive layer was changed to 7.30 parts to 3.30 parts. The average particle diameter of the TiO ₂ particles coated with SnO ₂ doped with antimony oxide was 0.63 μm. As a result, Rzjis on the surface of the conductive layer was 1.60 μm, and the volume resistivity of the conductive layer was 5.0 × 10 ⁵ Ω · cm. In addition, no phenolic compound was used in the charge generation layer.

As can be seen from the above results, according to the present invention, it is possible to cover defects on the support surface, improve the coating property of the photosensitive layer, improve the adhesion between the support and the photosensitive layer, protect against electrical breakdown of the photosensitive layer, An electrophotographic photosensitive member in which a conductive layer, an intermediate layer, a charge generation layer, and a charge transport layer are provided in this order on a support in order to improve chargeability and charge injection from the support to the photosensitive layer. And an electrophotographic photosensitive member in which the occurrence of a ghost phenomenon is suppressed even when the volume resistivity of the conductive layer exceeds 8.0 × 10 ⁸ Ω · cm and is 1.0 × 10 ¹¹ Ω · cm or less. Can be provided using oxygen-deficient SnO ₂ having excellent reusability.

  Further, according to the present invention, a process cartridge and 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. 1 shows an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge of the present invention.

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 1 Electrophotographic photosensitive member 2 Axis 3 Charging means (primary charging means)
4 exposure light (image exposure light)
5 Developing means 6 Transfer means (transfer roller)
7 Cleaning means (cleaning blade)
8 Fixing means 9 Process cartridge 10 Guide means 11 Pre-exposure light P Transfer material (paper, etc.)

Claims (7)

An electrophotographic photoreceptor having a conductive layer, an intermediate layer, a charge generation layer, and a charge transport layer in this order on a support, wherein the conductive layer contains at least metal oxide particles and a binder resin. The average particle diameter of the metal oxide particles is 0.20 to 0.60 μm, the metal oxide particles are titanium oxide particles coated with oxygen-deficient tin oxide, and the volume resistivity of the conductive layer is 8 An electrophotographic photosensitive member, which is more than 0.0 × 10 ⁸ Ω · cm and not more than 1.0 × 10 ¹¹ Ω · cm, and the charge generation layer contains a phenol compound. The electrophotographic photoreceptor according to claim 1, wherein the phenol compound is a compound represented by the general formula (1) or (2).

(Wherein R ₁ , R ₂ , R ₄ and R ₅ may be the same or different and are selected from an optionally substituted alkyl group, aryl group, aralkyl group, alkenyl group, alkoxy group or acyl group) R ₃ is selected from a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, and an optionally substituted alkyl group, aryl group, aralkyl group, alkenyl group, alkoxy group or acyl group. A divalent alkylene group which may have a substituent, a divalent alkylene group which may have an oxygen atom interposed between carbon-carbon bonds, n represents an integer of 2 to 4. Y represents a hydrogen atom. (A carbon atom or a sulfur atom which may be present, provided that when n is 2, Y may be a single bond.)   The electrophotographic photosensitive member according to claim 1 or 2, wherein a mass ratio G / F of the phenol compound (F) and the charge generation material (G) contained in the charge generation layer is 2.5 to 6.8.   The electrophotographic photosensitive member according to claim 1, wherein a mass ratio P / B of the metal oxide particles (P) and the binder resin (B) of the conductive layer is 2.3 to 3.3.   The electrophotographic photosensitive member according to claim 1, wherein the conductive layer has a thickness of 10 to 25 μm.   6. An electrophotographic photosensitive member according to claim 1, charging means for charging the surface of the electrophotographic photosensitive member, and an electrostatic latent image on the surface of the electrophotographic photosensitive member being developed with toner. Developing means for forming an image, transfer means for transferring a toner image on the surface of the electrophotographic photosensitive member to a transfer material, and cleaning for cleaning toner remaining on the surface of the electrophotographic photosensitive member after transfer A process cartridge which integrally supports at least one means selected from the group consisting of means and is detachable from an electrophotographic apparatus main body.   6. The electrophotographic photosensitive member according to claim 1, a charging unit for charging the surface of the electrophotographic photosensitive member, and the surface of the electrophotographic photosensitive member charged by the charging unit is exposed to an electrostatic latent image by exposure. An exposure means for forming an image, a developing means for developing an electrostatic latent image on the surface of the electrophotographic photosensitive member formed by the exposure means with toner to form a toner image, and a developing means An electrophotographic apparatus comprising transfer means for transferring a toner image on the surface of the electrophotographic photosensitive member to a transfer material.

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