JP2013190565A - Conductive support, electrophotographic photoreceptor using the conductive support, electrophotographic cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive support, an electrophotographic photoreceptor using the conductive support, an electrophotographic cartridge, and an image forming apparatus, capable of reducing vibration of the electrophotographic photoreceptor and preventing abnormal sound from occurring, without adding a member such as a vibration control member.SOLUTION: A conductive support includes mainly aluminum and at least one of nickel and a rare-earth element. When a surface of the conductive support is observed by magnifying it 500 times with a scan type electron microscope, the average number per unit area of at least one of an intermetallic compound based on the aluminum and the nickel and an intermetallic compound based on the aluminum and the rare-earth element is not less than 0.005 pieces/μmand not more than 0.1 pieces/μm. Further, there are provided an electrophotographic photoreceptor using the conductive support, an electrophotographic cartridge, and an image forming apparatus.

Description

  The present invention relates to a conductive support provided in an image forming apparatus such as a copying machine or a printer, an electrophotographic photosensitive member using the conductive support, an electrophotographic cartridge, and an image forming apparatus.

  An image forming apparatus such as a laser printer or a copying machine includes an electrophotographic cartridge. The electrophotographic cartridge is a member for transferring contents to be represented such as characters and figures onto a recording medium such as paper, and an electrophotographic photosensitive member on which the transferred contents are formed is disposed. Therefore, the electrophotographic cartridge is also provided with various means for forming the content to be transferred on the electrophotographic photosensitive member. Examples thereof include means for performing development, charging, and cleaning.

  In order to form an image, it is necessary to charge the electrophotographic photosensitive member to an appropriate potential, and a charging unit is used for this purpose. There are several types of charging means. In recent years, contact-type charging means have come to be used from the viewpoint of generating less harmful substances such as ozone and reducing power consumption.

  The contact-type charging unit is a unit in which a charging unit such as a roller, a brush, or a blade is brought into direct contact with the electrophotographic photosensitive member, and a voltage is applied between both to charge the electrophotographic photosensitive member to a predetermined potential.

  Thus, in order to use the contact-type charging unit, a DC voltage superimposed with an AC voltage is applied to the charging roller in order to charge the charging unit. However, at this time, a charging noise is generated along with the discharge. In addition, when an alternating current flows in the conductor, the conductor vibrates, so that the charging roller vibrates during operation, and the electrophotographic photosensitive member also vibrates at the same time, so that a large charging sound and vibration sound are generated.

  On the other hand, as described below, a technique for suppressing the charging noise and vibration noise has been proposed.

  Patent Document 1 describes a technique for filling a viscoelastic material inside an electrophotographic photosensitive member, and a technique for closely adhering the viscoelastic material in layers. However, in this technique, there is a possibility that the electrophotographic photosensitive member is deformed by press-fitting a viscoelastic material inside the electrophotographic photosensitive member. Further, there is a possibility that the electrophotographic photosensitive member is heated by the use of the image forming apparatus and the viscoelastic material expands to cause deformation.

  Patent Document 2 discloses a technique for holding a weight member inside an electrophotographic photosensitive member via an elastic member. However, adding a member having such a weight is not preferable in terms of production and product, and is to be avoided.

  Patent Document 3 discloses a technique in which an insert made of a rigid body or an elastic body is inserted into an electrophotographic photosensitive member, and the gap is filled with an adhesive and fixed. However, if this is the case, it also adds an insert and was preferred to avoid. Further, the influence on the electrophotographic photosensitive member due to the volume change when the adhesive is cured is also a problem.

  Patent Document 4 discloses a technique in which a cleaning device including a blade is provided with a vibration absorbing unit. However, it is also necessary to provide a vibration absorber in the cleaning device.

  Patent Document 5 discloses a technique for filling a resin filler having a specific linear expansion coefficient inside an electrophotographic photosensitive member. However, this also requires the addition of a filler, and the processing accuracy of the filler is particularly required in the present technology.

  Patent Document 6 discloses a technique in which an anti-vibration material including a metal cylindrical member and an elastic material provided on the outer surface of the cylindrical member is disposed inside the electrophotographic photosensitive member. However, it is necessary to add an anti-vibration material, and there is a possibility that the electrophotographic photosensitive member may be deformed by press-fitting the anti-vibration material inside the electrophotographic photosensitive member.

  Patent Document 7 discloses a technique in which a damping material is bonded to a cleaning blade. However, this technique also requires the addition of damping material. Further, the rigidity of the cleaning blade is increased, which may affect the original function of the cleaning blade.

  Patent Document 8 discloses a technique in which a silencer including a damping resin molding pellet is disposed on the inner peripheral surface or outer peripheral surface of an electrophotographic photosensitive member. However, this technique also requires the addition of a silencer.

  Patent Document 9 discloses a technique in which a magnet is provided on a blade holder that holds a blade for cleaning the surface of a photoreceptor or a holder bracket that supports the blade holder. However, this technique also requires a magnet.

  Patent Document 10 discloses a technique for defining the cylindricity of an electrophotographic photosensitive member and arranging a vibration suppressing member inside the electrophotographic photosensitive member. However, this technique also requires an additional vibration suppression member. Further, non-uniformity occurs in the close contact between the electrophotographic photosensitive member and the vibration suppressing member, and as a result, the degree of vibration suppression may vary.

  Patent Document 11 discloses a technique in which a vibration suppression material is inserted inside an electrophotographic photosensitive member and a relationship between the content area of the electrophotographic photosensitive member and the outer peripheral surface area of the vibration suppressing material is defined. However, this technique also requires the use of vibration suppression materials.

  Patent Document 12 discloses a technique in which a damping material having a substantially C-shaped cross section is disposed on an electrophotographic photosensitive member, and the charging roller contains a damping component. However, even in this technique, it is necessary to use a damping material. Also, Patent Document 12 describes the technical problems of Patent Documents 1 to 11 listed above.

  In Patent Document 13, a cylindrical resin insertion member having a slit and a constriction in the longitudinal direction is disposed inside the electrophotographic photosensitive member so as not to substantially increase the weight of the electrophotographic photosensitive member. Techniques to do this are disclosed. However, this technique also requires the addition of an insertion member.

JP-A-3-105348 JP-A-5-35166 JP-A-5-35167 Japanese Patent Laid-Open No. 5-341701 JP-A-8-146636 JP 2001-235971 A JP 2002-244521 A International Publication No. 00/49466 Pamphlet Japanese Patent Laid-Open No. 5-188833 JP 2002-116661 A JP 2002-149006 A JP 2005-62463 A JP-A-8-54804

  Therefore, in view of the above problems, the present invention provides a conductive support that can suppress the vibration of the electrophotographic photosensitive member without adding a member such as the vibration damping member described above, and can suppress the generation of abnormal noise. The issue is to provide. In addition, an electrophotographic photosensitive member, an electrophotographic cartridge, and an image forming apparatus using the conductive support are provided.

As a result of intensive studies in view of these current situations, the present inventors have made the electrophotographic photosensitive member contain at least one of Ni, a rare earth element, and a misch metal containing the rare earth element in the conductive support. The present invention has been completed by finding out that it is possible to suppress vibration and suppress the generation of abnormal noise.
That is, the first aspect of the present invention is a conductive support used for an electrophotographic photosensitive member, which is mainly composed of aluminum, contains at least one of nickel and rare earth elements, and has a conductive support. The average number of intermetallic compounds based on aluminum and nickel per unit area and intermetallic compounds based on aluminum and rare earth elements when the surface of the body is observed with a scanning electron microscope magnified 500 times There is a conductive support, characterized in that 0.005 pieces / [mu] m ² or more 0.1 or [mu] m ² or less.

  Here, “consisting mainly of aluminum” means that 50% by mass or more of the material constituting the conductive support is aluminum.

  In the first embodiment, the rare earth element can be at least one element selected from the group consisting of lanthanum, cerium, praseodymium, and neodymium.

  The second aspect of the present invention is an electrophotographic photosensitive member in which a photosensitive layer having a charge generation function and a charge transport function is formed on the surface of the conductive support of the first aspect.

  In the second embodiment, a polyarylate resin may be contained as a binder resin for the photosensitive layer.

  Moreover, polyarylate resin can also contain the repeating unit represented by following formula [1].

In the formula [1], Ar ^{1 to} Ar ⁴ each independently represent an arylene group which may have a substituent, and X represents a single bond, an oxygen atom, a sulfur atom, or a group represented by the following formula [2]. Or a group represented by the following formula [3], wherein R ¹ and R ² in the formula [2] each independently represent a hydrogen atom, an alkyl group, or an aryl group, and R ¹ and R ² And R ³ in the formula [3] may be an alkylene group, an arylene group, or a group represented by the following formula [4], and in the formula [4] R ⁴ and R ⁵ in the formula independently represent an alkylene group, and Ar ⁵ represents an arylene group. K in Formula [1] represents the integer of 0-5. However, when K = 0, one of Ar ³ and Ar ⁴ is an arylene group having a substituent. Further, in the formula [1], Y is a single bond, an oxygen atom, a sulfur atom, or a group represented by the following formula [5]. In the formula [5], R ⁶ and R ⁷ are each independently It represents a hydrogen atom, an alkyl group, an alkoxy group, or an aryl group, and R ⁶ and R ⁷ may be bonded to form a ring.

  According to a third aspect of the present invention, there is provided an electrophotographic photosensitive member according to the second aspect, a charging unit for charging the electrophotographic photosensitive member, an exposure unit for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image, an electron An electrophotographic cartridge comprising at least one of developing means for developing an electrostatic latent image formed on a photographic photosensitive member and cleaning means for cleaning the electrophotographic photosensitive member.

  According to a fourth aspect of the present invention, there is provided the electrophotographic photosensitive member according to the second aspect, a charging unit for charging the electrophotographic photosensitive member, an exposure unit for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image, and an electron An image forming apparatus comprising developing means for developing an electrostatic latent image formed on a photographic photosensitive member.

  According to the present invention, the vibration of the electrophotographic photosensitive member can be suppressed without adding a member such as a vibration damping member, and the generation of abnormal noise can be reduced. However, the present invention does not prevent the addition of a member for vibration suppression, and a vibration suppression member may be used in order to exhibit further effects.

It is a figure explaining the structure of the electrophotographic cartridge in one embodiment. It is a figure showing the profile of hardness measurement. 1 is a diagram showing an X-ray diffraction spectrum of a charge generation material used in Example 1. FIG.

  Hereinafter, the present invention will be described based on embodiments, but the present invention is not limited to the following embodiments, and can be arbitrarily modified without departing from the gist of the present invention.

<< Electrophotographic cartridge 1 >>
An image forming apparatus according to an embodiment of the present invention includes an electrophotographic cartridge 1 including an electrophotographic photosensitive member. FIG. 1 conceptually shows the configuration of the electrophotographic cartridge 1. The electrophotographic cartridge 1 has a casing 2, an electrophotographic photosensitive member 3 so as to be enclosed in the casing 2, charging means 4 for charging the electrophotographic photosensitive member 3, and the charged electrophotographic photosensitive member 3. An exposure unit 5 that performs image exposure to form an electrostatic latent image, a developing unit 6 that develops the electrostatic latent image with toner, a transfer unit 7 that transfers the toner from the electrophotographic photosensitive member 3 to the transfer target P, and a cleaning unit 8. And fixing means 9. Each will be described below.

<Housing 2>
The housing 2 is a member that forms an outline of the electrophotographic cartridge 1, and is configured so that each member to be described later can be included therein. As a result, the electrophotographic cartridge 1 can be handled as a unit, and the convenience is improved.

<Electrophotographic photoreceptor 3>
The electrophotographic photoreceptor 3 has a conductive support that functions as a support and has conductivity, an undercoat layer formed on the surface of the conductive support, and a photosensitive layer provided on the undercoat layer. doing. Each will be described in detail below.

[Conductive support]
The conductive support used in the present embodiment contains at least one of nickel (Ni) and rare earth elements in aluminum or an aluminum alloy, and is an intermetallic material based on aluminum (Al) and nickel (Ni). Crystallized product by compound (hereinafter sometimes referred to as “Al-Ni crystallized product”), or crystallized product by intermetallic compound based on aluminum and rare earth element (hereinafter “Al-rare earth crystallized product”) At least one of the above).

More specifically, when the surface of the conductive support is magnified 500 times with a scanning electron microscope, at least one of the Al-Ni crystallized product and the Al-rare earth crystallized product is 0.005 / It exists at not less than 0.1 μm ^{2 and not} more than 0.1 μm ² . The lower limit is preferably 0.008 pieces / μm ² or more, more preferably 0.01 pieces / μm ² or more, and the upper limit is preferably 0.08 pieces / μm ² or less, more preferably 0.06 pieces / μm ^2. μm ² or less.

  Here, the conductive support is mainly made of aluminum. “Mainly formed of aluminum” means that 50% by mass or more of aluminum is based on the entire conductive support.

  The rare earth element is preferably at least one selected from the group consisting of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), and a misch metal containing any of them.

  The type of aluminum alloy used here is not particularly limited, but is preferably a 6000 series, 5000 series, or 3000 series aluminum alloy that is often used as a conductive support for an electrophotographic photosensitive member.

  By allowing at least one of a crystallized product of an Al—Ni intermetallic compound or a crystallized product of an Al—rare earth element intermetallic compound to exist in the conductive support as described above, Vibration during operation can be suppressed. This can absorb vibration energy and suppress vibrations by the crystal-matrix boundary, viscous flow at the crystal grain boundary and cell grain boundary, and micro defects in the crystal such as dislocations, vacancies and stacking faults. It is thought that it is from.

  The conductive support may be provided with an anodic oxide coating on the surface thereof. When applying an anodized film, it is preferable to perform a sealing treatment by a known method. Examples of the anodizing method include anodizing in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, boric acid, and sulfamic acid. Among them, anodizing treatment in sulfuric acid is possible. preferable.

In the case of anodization in sulfuric acid, various conditions are arbitrary as long as the desired anodization treatment can be performed. Among them, the sulfuric acid concentration is 100 g / L or more and 300 g / L or less, and the dissolved aluminum concentration is 2 g / L or more and 15 g / L. Hereinafter, the liquid temperature is preferably 15 ° C. or higher and 30 ° C. or lower, the electrolysis voltage is 10 V or higher and 20 V or lower, and the current density is preferably 0.5 A / dm ² or higher and 2 A / dm ² or lower.

  The anodic oxide film thus formed is preferably subjected to a sealing treatment. The sealing treatment can be performed by a known method. As the sealing treatment method, for example, a low-temperature sealing treatment in which the sealing treatment is immersed in an aqueous solution (nickel fluoride aqueous solution) containing nickel fluoride as a main component, or A high temperature sealing treatment in which the component is immersed in an aqueous solution containing nickel acetate (nickel acetate aqueous solution) is preferred.

  The concentration of nickel fluoride in the nickel fluoride aqueous solution used in the case of the low-temperature sealing treatment is not particularly limited, but it should be used so as to have a concentration of 3 g / L or more and 6 g / L or less. Is preferred. Moreover, in order to advance a sealing process smoothly, process temperature is 25 degreeC or more, Preferably it is 30 degreeC or more, and the upper limit is 40 degrees C or less, Preferably it is 35 degrees C or less.

  Here, the pH of the nickel fluoride aqueous solution is usually 4.5 or more, preferably 5.5 or more, and the upper limit thereof is usually 6.5 or less, preferably 6.0 or less. As the pH adjuster, any known substance can be used. For example, oxalic acid, boric acid, formic acid, acetic acid, sodium hydroxide, sodium acetate, aqueous ammonia and the like can be used. In addition, a pH adjuster may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios and combinations.

  The treatment time is preferably in the range of 1 minute to 3 minutes per 1 μm of film thickness. In order to further improve the physical properties of the film, for example, cobalt fluoride, cobalt acetate, nickel sulfate, a surfactant and the like may be mixed in the nickel fluoride aqueous solution. After the above treatment, the low-temperature sealing treatment can be completed by washing with water, drying, or the like, if necessary.

  Moreover, as a sealing agent in the case of said high temperature sealing process, metal salt aqueous solution, such as nickel acetate, cobalt acetate, lead acetate, nickel acetate-cobalt, barium nitrate, can be used, but the aqueous solution of nickel acetate is used. It is preferable to use it. When using nickel acetate aqueous solution, it is preferable to use the density | concentration of nickel acetate in nickel acetate aqueous solution within the concentration range of 5 g / L or more and 20 g / L or less.

  Further, the treatment temperature is usually 80 ° C. or higher, preferably 90 ° C. or higher, and the upper limit is usually 100 ° C. or lower, preferably 98 ° C. or lower. The pH of the aqueous nickel acetate solution is preferably in the range of 5.0 or more and 6.0 or less. As the pH adjuster, aqueous ammonia, sodium acetate, or the like can be used. In addition, a pH adjuster may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios and combinations.

  The treatment time is usually 10 minutes or longer, preferably 20 minutes or longer. In this case, sodium acetate, organic carboxylic acid, anionic and nonionic surfactants may be mixed in the nickel acetate aqueous solution in order to improve the film properties. After the above treatment, the high temperature sealing treatment can be completed by washing with water, drying or the like, if necessary.

When the average film thickness is thick, strong sealing conditions may be required due to high concentration of the sealing liquid and high temperature / long time processing. Therefore, productivity is deteriorated and surface defects such as stains, dirt, and dusting are easily generated on the coating surface. From such a viewpoint, the average film thickness of the anodized film is usually 20 μm or less, preferably 7 μm or less.
The surface of the conductive support may be smooth, or may be roughened by using a special cutting method or polishing. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the conductive support. In order to reduce the cost, it is possible to use the drawing tube as it is without cutting. Especially when using non-cutting conductive supports such as drawing, impact processing, ironing, etc., the process eliminates dirt, foreign matter, and other small scratches on the surface. Since a body is obtained, it is preferable.

  The conductive support of this embodiment is tubular. Although the outer diameter is not particularly limited, it is effective to reduce the outer diameter of the electrophotographic photosensitive member in recent years due to the progress of miniaturization of printers and MFPs. The preferable outer diameter of the body is 20 mm or less, more preferably 16 mm or less. On the other hand, the outer diameter is usually 10 mm or more.

  The tubular conductive support is used after being rotated around the axial direction of the tube. Accordingly, when there is a large eccentricity during the rotation, vibration or abnormal noise is generated. Therefore, it goes without saying that the eccentricity of the conductive support applied to the present embodiment is suppressed at least as much as that of the conductive support that is normally used.

[Underlayer]
On the surface of the conductive support, an undercoat layer may be provided between the surface of the conductive support and a photosensitive layer described in detail later. The undercoat layer has a function of improving adhesiveness, blocking property and the like between the conductive support and the photosensitive layer. Therefore, as the undercoat layer, for example, a resin, a resin in which particles such as a metal oxide are dispersed, or the like can be used. The undercoat layer may be a single layer or a plurality of layers.

  Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. One of these may be used alone, or two or more thereof may be used in any ratio and combination.

  Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicone. Any one of these treatments may be used, or two or more thereof may be applied.

  As the crystal form of the titanium oxide particles, for example, any of rutile, anatase, brookite, and amorphous can be used. In addition, the titanium oxide particles may have only one crystal type, or two or more crystal types may be included in any ratio and combination. Although the particle size of the metal oxide particles is not particularly limited, the average primary particle size is usually 10 nm or more, from the viewpoint of the properties of the binder resin or the like that is the raw material of the undercoat layer and the stability of the solution, Usually, it is 100 nm or less, preferably 50 nm or less. This average primary particle size can be measured by, for example, a transmission electron microscope (TEM) photograph.

  The undercoat layer is preferably formed by dispersing metal oxide particles in a binder resin. Such an undercoat layer is, for example, a solution in which metal oxide particles are dispersed in a solution in which a binder resin is dissolved, and the metal oxide particles are dispersed (hereinafter referred to as “undercoat layer forming coating solution” as appropriate). It is preferable to form it by coating. Examples of the binder resin used for the undercoat layer include epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, polyimide resin. , Vinylidene chloride resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, polyurethane resin, polyacrylic acid resin, polyacrylamide resin, polyvinyl pyrrolidone resin, polyvinyl pyridine resin, water-soluble polyester resin, nitrocellulose, etc. Cellulose ester resin, cellulose ether resin, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium chelate compound, Organozirconium compounds such as benzalkonium alkoxide compounds, titanyl chelate compounds, organic titanyl compounds such as titanyl alkoxide compound, silane coupling agent, and the like. One of these may be used alone, or two or more thereof may be used in any ratio and combination. Moreover, you may use with the shape hardened with the hardening | curing agent. Among them, alcohol-soluble copolymerized polyamides, modified polyamides, and the like can be preferably applied because they exhibit good dispersibility and coatability.

  The amount of the metal oxide particles used is not particularly limited, but from the viewpoint of stability and coating properties of the coating solution for forming the undercoat layer, 10 parts by mass or more and 500 parts by mass with respect to 100 parts by mass of the binder resin. The following is preferred. When the metal oxide particles are contained in the coating solution for forming the undercoat layer, the metal oxide particles are usually present dispersed in the coating solution. As a method for dispersing the metal oxide particles in the coating liquid for forming the undercoat layer, for example, a known mechanical grinding device such as a ball mill, a sand grind mill, a planetary mill, or a roll mill is used. Can be dispersed. Among these, it is preferable to disperse using a dispersion medium.

  As a dispersion device when dispersing using a dispersion medium, any known dispersion device may be used. For example, a pebble mill, a ball mill, a sand mill, a screen mill, a gap mill, a vibration mill, Examples include paint shakers and attritors. Among these, those capable of being dispersed by circulating the coating solution are preferable, and a sand mill, a screen mill, and a gap mill are used from the viewpoints of dispersion efficiency, fineness of the reached particle diameter, ease of continuous operation, and the like. The sand mill may be either a vertical type or a horizontal type. The disc shape of the sand mill can be any plate type, vertical pin type, horizontal pin type or the like.

  Since the dispersion medium is generally in the shape of a true sphere, the average particle size is determined by, for example, a method of sieving using a sieve described in JIS 8801: 2000, for example, an image analyzer such as LUZEX50 manufactured by Nireco Corporation. It can be obtained by image analysis or the like used. The density can be measured by, for example, the Archimedes method. Furthermore, the sphericity can be obtained by an image analysis device such as LUZEX50 manufactured by Nireco Corporation.

  The average particle size of the dispersion medium is usually 5 μm or more, preferably 10 μm or more, and the upper limit is usually 200 μm or less, preferably 100 μm or less. In general, a uniform dispersion can be obtained in a short time by using a dispersion medium having a small particle diameter. However, if the particle diameter becomes too small, the mass of the dispersion medium becomes small and efficient dispersion is achieved. May not be possible.

The density of the dispersion medium is usually 5.5 g / cm ³ or more, preferably 5.9 g / cm ³ or more, more preferably 6.0 g / cm ³ or more. In general, when a dispersion medium having a higher density is used for dispersion, a uniform dispersion tends to be obtained in a shorter time.

  The sphericity of the dispersion medium is preferably 1.08 or less, more preferably 1.07 or less. The dispersion medium is not particularly limited, but is insoluble in the coating solution for forming the undercoat layer and has a specific gravity larger than that of the coating solution for forming the undercoat layer, It is preferable that it does not react or alter the coating solution for forming the undercoat layer. Specific examples of dispersion media include steel balls such as chrome balls (ball balls for ball bearings) and carbon balls (carbon steel balls); stainless steel balls; ceramic balls such as silicon nitride balls, silicon carbide, zirconia, and alumina; titanium nitride And spheres coated with a film of titanium carbonitride and the like. Among these, ceramic spheres are preferable, and zirconia fired balls are particularly preferable. More specifically, it is particularly preferable to use zirconia fired beads described in Japanese Patent No. 3400836. One of these may be used alone, or two or more thereof may be used in any ratio and combination.

  In the liquid in which the undercoat layer is dispersed in a solvent in which methanol and 1-propanol are mixed at a mass ratio of 7: 3 (hereinafter referred to as “dispersion for measuring the undercoat layer” as appropriate), a metal oxide is used. The particles have a volume average particle diameter measured by a dynamic light scattering method of usually 20 nm or more, and the upper limit is usually 0.1 μm or less, preferably 95 nm or less, more preferably 90 nm or less.

In addition, as a specific measuring method by the dynamic light scattering method, for example, a method described in JP-A-2007-334335 can be used.
Further, the metal oxide particles in the dispersion for measuring the undercoat layer have a cumulative 90% particle diameter measured by a dynamic light scattering method of usually 10 nm or more, preferably 20 nm or more, more preferably 50 nm or more. The upper limit is usually 0.3 μm or less, preferably 0.25 μm or less, more preferably 0.2 μm or less.

  When a metal oxide particle aggregate large enough to penetrate the front and back of the undercoat layer is contained by aggregation of metal oxide particles in the undercoat layer, the large metal oxide particle aggregate causes Defects can occur. Further, when a contact type is used as the charging means, when the photosensitive layer is charged, the charge moves from the photosensitive layer to the conductive support through the metal oxide particles, and the charging is appropriately performed. There was also a possibility that it could not be done. On the other hand, if the cumulative 90% particle size is very small, there will be very few large metal oxide particles that can cause defects. As a result, in the image forming apparatus using the electrophotographic photosensitive member of the present invention, it is possible to suppress the occurrence of defects and the inability to appropriately charge, and high-quality image formation is possible.

  The thickness of the undercoat layer is not particularly limited. However, from the viewpoint of improving the electrical characteristics, the strong exposure characteristics, the image characteristics, the repeat characteristics, and the applicability during production of the electrophotographic photosensitive member, it is usually 0. It is 01 μm or more, preferably 0.1 μm or more, and usually 30 μm or less, preferably 20 μm or less.

[Photosensitive layer]
The photosensitive layer is a layer having a function of generating a charge and a function of transporting a charge, and a configuration of a known electrophotographic photosensitive member can be adopted as the configuration. Examples thereof include a single layer type photosensitive layer and a laminated type photosensitive layer. The single-layer type photosensitive layer is a single-layer photosensitive layer having both a function of generating charges by dissolving or dispersing a photoconductive material in a binder resin and a function of transporting charges. On the other hand, the laminated photosensitive layer is a photosensitive layer composed of a plurality of layers formed by laminating a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material.

  The photosensitive layer provided in this embodiment may be in any known form, but considering the mechanical properties, electrical characteristics, manufacturing stability, etc. of the electrophotographic photosensitive member comprehensively, it is a laminated type. An electrophotographic photoreceptor is preferred. In particular, a sequential lamination type photoreceptor in which a charge generation layer and a charge transport layer are laminated in this order on a conductive support is more preferable. The photosensitive layer preferably contains a polyarylate resin as a binder resin. When the polyarylate resin is used, the toner cleaning can be effectively performed, so that it is possible to further suppress the noise caused by the rotation of the electrophotographic photosensitive member. The polyarylate resin will be described below.

(Polyarylate resin)
The structure of the polyarylate resin preferably contained in the photosensitive layer is exemplified below. This is an example and is not limited to the structure shown below. The polyarylate resin contained in the photosensitive layer contains, for example, a repeating structure represented by the following general formula [1], and is produced by a known method, for example, with a divalent hydroxyaryl component and a dicarboxylic acid component. Can do.

In the general formula [1], Ar ^{1 to} Ar ⁴ may be the same or different, and each independently represents an arylene group which may have a substituent. The arylene group is not particularly limited, but an arylene group having 6 to 20 carbon atoms is preferable, and examples thereof include a phenylene group, a naphthylene group, an anthrylene group, a phenanthrylene group, and a pyrenylene group. Among these, a phenylene group and a naphthylene group are particularly preferable from the viewpoint of production cost. Further, when a phenylene group and a naphthylene group are compared, a phenylene group is more preferable in terms of ease of synthesis in addition to manufacturing cost. However, in the formula [1], when k = 0, when Ar ³ and Ar ⁴ are an unsubstituted arylene group at the same time, the adhesive property of the photosensitive layer is poor, so either one of Ar ³ and Ar ⁴ is An arylene group having a substituent.

The substituent that may be independently present in the arylene group is not particularly limited, and preferred examples include a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, a condensed polycyclic group, and a halogen group. Considering the mechanical properties as the binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the aryl group is preferably a phenyl group or a naphthyl group, and the halogen group is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. The alkoxy group is preferably a methoxy group, an ethoxy group, or a butoxy group. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and 1 to 2 carbon atoms. Are particularly preferable, and specifically, a methyl group is most preferable. The number of substituents for each of Ar ^{1 to} Ar ⁴ is not particularly limited, but is preferably 3 or less, more preferably 2 or less, and particularly preferably 1 or less.

Further, in the general formula [1], Ar ¹ and Ar ² are preferably the same arylene group having the same substituent, and particularly preferably an unsubstituted phenylene group. Ar ³ and Ar ⁴ are preferably the same arylene group, and particularly preferably a phenylene group having a methyl group.

In general formula [1], X represents a divalent organic residue having a single bond, an oxygen atom, a sulfur atom, a structure represented by the following formula [2], or a structure represented by the following formula [3]. Show. R ¹ and R ² in the formula [2] each independently represent a hydrogen atom, an alkyl group, or an aryl group, or a cycloalkylidene group formed by combining R ¹ and R ² . Examples of the alkyl group of R ¹ and R ² in the formula [2] include a methyl group, an ethyl group, a propyl group, and a butyl group, and examples of the aryl group include a phenyl group and a naphthyl group. In addition, examples of the cycloalkylidene group formed by combining R ¹ and R ² in the formula [2] include a cyclopentylidene group, a cyclohexylidene group, and a cycloheptylidene group. Furthermore, R ³ in the formula [3] represents an alkylene group, an arylene group, or a group represented by the following formula [4]. Examples of the alkylene group represented by R ³ in the formula [3] include a methylene group, an ethylene group, and a propylene group. Examples of the arylene group represented by R ³ in the formula [3] include a phenylene group and a terphenylene group. Examples of the group represented by the formula [4] include a group represented by the following formula [4a]. Among these, X is preferably an oxygen atom from the viewpoint of wear resistance.

  In general formula [1], k is an integer of 0 to 5, preferably an integer of 0 to 1, and most preferably 1 from the viewpoint of wear resistance.

In general formula [1], Y represents a single bond, a sulfur atom, an oxygen atom, or a divalent organic residue having a structure represented by the following formula [5]. R ⁶ and R ⁷ in the formula [5] each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a cycloalkylidene group formed by combining R ⁶ and R ⁷ . Considering the mechanical properties as the binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the aryl group is preferably a phenyl group or a naphthyl group, and the alkoxy group is preferably a methoxy group, an ethoxy group, or a butoxy group. preferable. Moreover, as an alkyl group, a C1-C10 alkyl group is preferable, More preferably, it is C1-C8, Most preferably, it is C1-2. Considering the simplicity of production of the divalent hydroxyaryl component used in producing the polyarylate resin, Y is a single bond, —O—, —S—, —CH ₂ —, —CH (CH ₃ ) —. , —C (CH ₃ ) ₂ — and cyclohexylidene are preferable, and —CH ₂ —, —CH (CH ₃ ) —, —C (CH ₃ ) ₂ — and cyclohexylidene are particularly preferable. Is —CH ₂ —, —CH (CH ₃ ) —.

Further, the polyarylate resin is more preferably a polyarylate resin containing a repeating structure represented by the following general formula [6]. In the following general formula [6], Ar ^{16 to} Ar ¹⁹ each independently represent an arylene group which may have a substituent, and R ⁸ represents a hydrogen atom or an alkyl group.

In the general formula [6], Ar ^{16 to} Ar ¹⁹ respectively correspond to Ar ^{1 to} Ar ⁴ in the general formula [1], and particularly preferably a phenylene group which may have a substituent. It is. Moreover, as a preferable substituent, it is a hydrogen atom or an alkyl group, Most preferably, it is a methyl group. Further, in the general formula [6], Ar ¹⁸ and Ar ¹⁹ are the same phenylene group having a methyl group, and Ar ¹⁶ and Ar ¹⁷ are particularly preferably phenylene groups having no substituent. R ⁸ represents a hydrogen atom or an alkyl group, and the alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably a methyl group. .

  The divalent hydroxyaryl component to be a divalent hydroxyaryl residue in the polyarylate resin is represented by the following general formula [7], but is preferably represented by the following general formula [8].

Ar ³ , Ar ⁴ and Y in the general formula [7] are as described above.

In the general formula [8], Ar ¹⁸ and Ar ¹⁹ independently represent a phenylene group which may have a substituent, and R ⁸ represents a hydrogen atom or a methyl group. Specifically, when R ⁸ in the general formula [8] is a hydrogen atom, bis (2-hydroxyphenyl) methane, (2-hydroxyphenyl) (3-hydroxyphenyl) methane, (2-hydroxyphenyl) ( 4-hydroxyphenyl) methane, bis (3-hydroxyphenyl) methane, (3-hydroxyphenyl) (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) methane, bis (2-hydroxy-3-methylphenyl) Methane, bis (2-hydroxy-3-ethylphenyl) methane, (2-hydroxy-3-methylphenyl) (3-hydroxy-4-methylphenyl) methane, (2-hydroxy-3-ethylphenyl) (3- Hydroxy-4-ethylphenyl) methane, (2-hydroxy-3-methylphenyl) (4-hydroxy -3-methylphenyl) methane, (2-hydroxy-3-ethylphenyl) (4-hydroxy-3-ethylphenyl) methane, bis (3-hydroxy-4-methylphenyl) methane, bis (3-hydroxy-4) -Ethylphenyl) methane, (3-hydroxy-4-methylphenyl) (4-hydroxy-3-methylphenyl) methane, (3-hydroxy-4-ethylphenyl) (4-hydroxy-3-ethylphenyl) methane, Examples include bis (4-hydroxy-3-methylphenyl) methane and bis (4-hydroxy-3-ethylphenyl) methane. When R ⁸ is a methyl group, 1,1-bis (2-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) -1- (3-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) ) -1- (4-hydroxyphenyl) ethane, 1,1-bis (3-hydroxyphenyl) ethane, 1- (3-hydroxyphenyl) -1- (4-hydroxyphenyl) ethane, 1,1-bis ( 4-hydroxyphenyl) ethane, 1,1-bis (2-hydroxy-3-methylphenyl) ethane, 1,1-bis (2-hydroxy-3-ethylphenyl) ethane, 1- (2-hydroxy-3-) Methylphenyl) -1- (3-hydroxy-4-methylphenyl) ethane, 1- (2-hydroxy-3-ethylphenyl) -1- (3-hydroxy-4-ethylphenyl) Enyl) ethane, 1- (2-hydroxy-3-methylphenyl) -1- (4-hydroxy-3-methylphenyl) ethane, 1- (2-hydroxy-3-ethylphenyl) -1- (4-hydroxy) -3-ethylphenyl) ethane, 1,1-bis (3-hydroxy-4-methylphenyl) ethane, 1,1-bis (3-hydroxy-4-ethylphenyl) ethane, 1- (3-hydroxy-4) -Methylphenyl) -1- (4-hydroxy-3-methylphenyl) ethane, 1- (3-hydroxy-4-ethylphenyl) -1- (4-hydroxy-3-ethylphenyl) ethane, 1,1- Bis (4-hydroxy-3-methylphenyl) ethane and 1,1-bis (4-hydroxy-3-ethylphenyl) ethane are mentioned.

Among these, when R ⁸ in the general formula [8] is a hydrogen atom, bis (4-hydroxyphenyl) methane, (2-hydroxyphenyl) is considered in consideration of the convenience of production of the divalent hydroxyaryl component. ) (4-hydroxyphenyl) methane, bis (2-hydroxyphenyl) methane, bis (4-hydroxy-3-methylphenyl) methane, bis (4-hydroxy-3-ethylphenyl) methane are particularly preferred. A combination of a plurality of divalent hydroxyaryl components can also be used.

When R ⁸ in the general formula [8] is a methyl group, 1,1-bis (4-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) -1- (4-hydroxyphenyl) ethane 1,1-bis (2-hydroxyphenyl) ethane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, and 1,1-bis (4-hydroxy-3-ethylphenyl) ethane are particularly preferable. A combination of a plurality of these divalent hydroxyaryl components can also be used.

  Although general formula [8] is contained in general formula [7], the compound of general formula [7] other than the illustration of the said general formula [8] is also demonstrated below.

  Specific examples of the divalent hydroxyaryl component represented by the general formula [7] include 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl, 2,4,3 ′, 5 ′. -Tetramethyl-3,4'-dihydroxybiphenyl, 2,2 ', 4,4'-tetramethyl-3,3'-dihydroxybiphenyl, bis (4-hydroxy-3,5-dimethylphenyl) ether, (4 -Hydroxy-3,5-dimethylphenyl) (3-hydroxy-2,4-dimethylphenyl) ether, bis (3-hydroxy-2,4-dimethylphenyl) ether, bis (4-hydroxy-3,5-dimethyl) Phenyl) methane, (4-hydroxy-3,5-dimethylphenyl) (3-hydroxy-2,4-dimethylphenyl) methane, bis (3-hydroxy-2,4-dimethylphenyl) L) Methane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) ethane, 1- (4-hydroxy-3,5-dimethylphenyl) -1- (3-hydroxy-2,4-dimethyl) Phenyl) ethane, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) ethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2- (4-hydroxy-3) , 5-dimethylphenyl) -2- (3-hydroxy-2,4-dimethylphenyl) propane, 2,2-bis (3-hydroxy-2,4-dimethylphenyl) propane, 1,1-bis (4- Hydroxy-3,5-dimethylphenyl) cyclohexane, 1- (4-hydroxy-3,5-dimethylphenyl) -1- (3-hydroxy-2,4-dimethylphenyl) cyclohexane Sun, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) cyclohexane, preferably 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl, bis ( 4-hydroxy-3,5-dimethylphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) ethane, 2,2 -Bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane. Alternatively, bis (2-hydroxyphenyl) ether, (2-hydroxyphenyl) (3-hydroxyphenyl) ether, (2-hydroxyphenyl) (4-hydroxyphenyl) ether, bis (3-hydroxyphenyl) ether, (3 -Hydroxyphenyl) (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) ether, bis (2-hydroxy-3-methylphenyl) ether, bis (2-hydroxy-3-ethylphenyl) ether, (2- Hydroxy-3-methylphenyl) (3-hydroxy-4-methylphenyl) ether, (2-hydroxy-3-ethylphenyl) (3-hydroxy-4-ethylphenyl) ether, (2-hydroxy-3-methylphenyl) ) (4-Hydroxy-3-methylphenyl) Ether, (2-hydroxy-3-ethylphenyl) (4-hydroxy-3-ethylphenyl) ether, bis (3-hydroxy-4-methylphenyl) ether, bis (3-hydroxy-4-ethylphenyl) ether, (3-hydroxy-4-methylphenyl) (4-hydroxy-3-methylphenyl) ether, (3-hydroxy-4-ethylphenyl) (4-hydroxy-3-ethylphenyl) ether, bis (4-hydroxy- 3-methylphenyl) ether, bis (4-hydroxy-3-ethylphenyl) ether, bis (4-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane, bis (2- Hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) ether, bis (4-hydroxy -3-methylphenyl) methane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4- Hydroxy-3-methylphenyl) cyclohexane, bis (4-hydroxy-3-methylphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,5) -Dimethylphenyl) ethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, bis (4-hydroxy-2,3,5-trimethylphenyl) phenylmethane, 1,1-bis (4-hydroxy-2,3,5-trimethylphenyl) ) Phenylethane, bis (4-hydroxyphenyl) -1-phenylmethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) -1-phenylpropane Bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) methoxymethane, 1,1-bis (4-hydroxyphenyl) -1-methoxyethane, 1,1- Bis (4-hydroxyphenyl) -1-methoxypropane, bis (4-hydroxy Eniru) dimethoxymethane and the like.

  Of these, bis (4-hydroxy-3,5-dimethylphenyl) methane and 2,2-bis (4-hydroxy-3,5-dimethylphenyl) are considered in consideration of the ease of production of the divalent hydroxyaryl component. ) Propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, or bis (4-hydroxyphenyl) ether, (2-hydroxyphenyl) (4-hydroxyphenyl) ether, bis (2 -Hydroxyphenyl) ether, bis (4-hydroxy-3-methylphenyl) ether, and bis (4-hydroxy-3-ethylphenyl) ether are particularly preferable, and a combination of these divalent hydroxyaryl components can be used. It is.

  The dicarboxylic acid component which is a dicarboxylic acid residue in the polyarylate resin is represented by the following general formula [9].

Ar ¹ , Ar ² , X, and k in the general formula [9] are as described above, and the dicarboxylic acid residues contained in the formula [9] are represented by the following general formulas [I] to [VI]. The dicarboxylic acid component represented by the following general formula [10] is preferable.

Ar ¹⁶ and Ar ¹⁷ in the general formula [10] are also as described above, and are preferably a phenylene group which may have a substituent.

  Specific examples of preferred dicarboxylic acid residues include diphenyl ether-2,2′-dicarboxylic acid residues, diphenyl ether-2,3′-dicarboxylic acid residues, diphenyl ether-2,4′-dicarboxylic acid residues, and diphenyl ether-3. , 3′-dicarboxylic acid residue, diphenyl ether-3,4′-dicarboxylic acid residue, diphenyl ether-4,4′-dicarboxylic acid residue, and the like. Among these, considering the simplicity of production of the dicarboxylic acid component, diphenyl ether-2,2′-dicarboxylic acid residue, diphenyl ether-2,4′-dicarboxylic acid residue, diphenyl ether-4,4′-dicarboxylic acid Residues are more preferred, and diphenyl ether-4,4′-dicarboxylic acid residues are particularly preferred.

  The polyarylate resin may be a resin containing another dicarboxylic acid component and enclosing the general formula [1] in a part of the structure. Specific examples of other dicarboxylic acid residues include adipic acid residues, suberic acid residues, sebacic acid residues, phthalic acid residues, isophthalic acid residues, terephthalic acid residues, toluene-2,5-dicarboxylic acid Residue, p-xylene-2,5-dicarboxylic acid residue, pyridine-2,3-dicarboxylic acid residue, pyridine-2,4-dicarboxylic acid residue, pyridine-2,5-dicarboxylic acid residue, pyridine -2,6-dicarboxylic acid residue, pyridine-3,4-dicarboxylic acid residue, pyridine-3,5-dicarboxylic acid residue, naphthalene-1,4-dicarboxylic acid residue, naphthalene-2,3-dicarboxylic acid An acid residue, naphthalene-2,6-dicarboxylic acid residue, biphenyl-2,2′-dicarboxylic acid residue, biphenyl-4,4′-dicarboxylic acid residue, preferably adipic acid residue, Seba Acid residue, phthalic acid residue, isophthalic acid residue, terephthalic acid residue, naphthalene-1,4-dicarboxylic acid residue, naphthalene-2,6-dicarboxylic acid residue, biphenyl-2,2′-dicarboxylic acid An acid residue and a biphenyl-4,4′-dicarboxylic acid residue, particularly preferably an isophthalic acid residue and a terephthalic acid residue. A combination of a plurality of these dicarboxylic acid residues can also be used. .

  In addition, when it has the dicarboxylic acid residue contained in this embodiment and the other dicarboxylic acid residue mentioned above, the dicarboxylic acid residue contained in this embodiment may be 70% or more as the number of repeating units. Preferably, it is 80% or more, more preferably 90% or more. Most preferably, it has only the dicarboxylic acid residue contained in this embodiment, that is, the case where the dicarboxylic acid residue contained in this embodiment is 100% as the number of repeating units.

  Further, the polyarylate resin included in the present embodiment can be mixed with other resins and used for the electrophotographic photosensitive member. Other resins used here include vinyl polymers such as polymethyl methacrylate, polystyrene, polyvinyl chloride, and copolymers thereof, polycarbonate, polyarylate, polyarylate polycarbonate, polysulfone, phenoxy, epoxy, silicone resin, etc. And other thermoplastic resins and various thermosetting resins. Of these resins, polycarbonate resin is preferable.

  The mixing ratio of the resin to be used in combination is not particularly limited, but it is preferable to use the resin in a range not exceeding the ratio of the polyarylate resin described above, and it is more preferable not to use another resin in combination.

  The viscosity average molecular weight of the polyarylate resin is not particularly limited, but is 10,000 or more, preferably 15000 or more, more preferably 20000 or more, and the upper limit is 300000 or less, preferably 200000 or less, more preferably 100000 or less. If the viscosity average molecular weight is excessively small, the mechanical strength of the photosensitive layer is lowered, which is not practical. On the other hand, if the viscosity average molecular weight is excessively large, it is difficult to apply and form the photosensitive layer to an appropriate film thickness.

(Binder resin other than polyarylate resin)
Hereinafter, other binder resins that can be used other than the polyarylate resin will be described. These resins may be used in combination with the polyarylate resin. When used together, the polyarylate resin is usually 30% by mass or more, preferably 50% by mass or more, in all binder resins used in the charge transport layer of the multilayer photoreceptor and the photosensitive layer of the single-layer photoreceptor. Preferably it is 80 mass% or more, Most preferably, it is 100 mass%.

  When forming a charge transport layer of a function-separated type photoreceptor having a charge generation layer and a charge transport layer (that is, a multilayer photoreceptor) and a photosensitive layer of a single layer photoreceptor, a compound is usually used to ensure film strength. In order to disperse the binder resin. The charge transport layer of the multilayer photoreceptor can be obtained by applying and drying a coating solution obtained by dissolving or dispersing a charge transport material and various binder resins in a solvent. The single-layer type photoreceptor can be obtained by applying and drying a coating solution obtained by dissolving or dispersing a charge generating substance, a charge transporting substance and various binder resins in a solvent.

  Examples of other binder resins include butadiene resins, styrene resins, vinyl acetate resins, vinyl chloride resins, acrylic ester resins, methacrylic ester resins, vinyl alcohol resins, polymers and copolymers of vinyl compounds such as ethyl vinyl ether, Polyvinyl butyral resin, polyvinyl formal resin, partially modified polyvinyl acetal, polycarbonate resin, polyester resin, polyamide resin, polyurethane resin, cellulose ester resin, phenoxy resin, silicone resin, silicone-alkyd resin, poly-N-vinylcarbazole resin, etc. It is done. These resins may be modified with a silicon reagent or the like. Of the above binder resins, polycarbonate resins are preferred. In addition, binder resin may be used individually by 1 type and may be used 2 or more types by arbitrary ratios and combinations.

  As the polycarbonate resin that can be used in combination with the polyarylate resin, a polycarbonate resin having a repeating structure represented by the following formula [11] is preferably used.

In formula [11], Ar ²¹ and Ar ²² each independently represent an arylene group which may have a substituent, and X ² represents a single bond or a divalent linking group. Examples of the arylene group include a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a naphthylene group, an anthrylene group, and a phenanthrylene group. Groups are preferred.

Ar ²¹ and Ar ²² may each independently have a substituent. Specific examples of the substituent include an alkyl group, an aryl group, a halogen group, and an alkoxy group. Among these, considering the mechanical properties as the binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the alkyl group is preferably a methyl group, an ethyl group, a propyl group, or an isopropyl group. The group is preferably a phenyl group or a naphthyl group, the halogen group is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, and the alkoxy group is preferably exemplified by a methoxy group, an ethoxy group, a propoxy group and a butoxy group.
In addition, when a substituent is an alkyl group, carbon number of the alkyl group is usually 1 or more, and usually 10 or less, preferably 8 or less, more preferably 2 or less.

Ar ²¹ and Ar ²² each independently have no substituent or preferably have one or two substituents, and have one or two substituents from the viewpoint of adhesiveness. Is more preferable, and it is particularly preferable to have one substituent from the viewpoint of slipperiness. As the substituent, an alkyl group is preferable, and a methyl group is particularly preferable.

In the above formula [11], X ² represents a single bond or a divalent linking group. Specific examples of suitable X ² include a sulfur atom, an oxygen atom, a sulfonyl group, a carbonyl group, a cycloalkylidene group such as cyclopentylidene and cyclohexylidene, and —CR ^c R ^d —.
Here, R ^c and R ^d each independently represent a hydrogen atom, an alkyl group, an aryl group, a halogen group, or an alkoxy group. Further, among R ^c and R ^d , when considering the mechanical properties as the binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the alkyl group includes a methyl group, an ethyl group, a propyl group, Isopropyl group is preferable, aryl group is preferably phenyl group or naphthyl group, halogen group is preferably fluorine atom, chlorine atom, bromine atom or iodine atom, and alkoxy group is methoxy group, ethoxy group, propoxy group or butoxy group Is preferred.

In addition, when ^Rc or ^Rd is an alkyl group, the carbon number of the alkyl group is usually 1 or more, usually 10 or less, preferably 8 or less, more preferably 2 or less.
Furthermore, considering the convenience in producing a divalent hydroxy compound that is usually used in producing a polycarbonate resin, X ² may be a sulfur atom, an oxygen atom, cyclohexylidene, or —CR ^c R ^d —. preferable. Among these, X ² is preferably —CR ^c R ^d —, R ^c and R ^d are more preferably a hydrogen atom or an alkyl group such as a methyl group, and from the viewpoint of wear resistance, R ^c and It is particularly preferable that at least one of R ^d is a hydrogen atom.

Examples of the diol component that forms these structures include bisphenol compounds and biphenol compounds.
Specific examples thereof include 4,4′-biphenol, 3,3′-dimethyl-4,4′-dihydroxy-1,1′-biphenyl, 3,3′-di (t-butyl) -4,4 ′. -Dihydroxy-1,1'-biphenyl, 3,3 ', 5,5'-tetramethyl-4,4'-dihydroxy-1,1'-biphenyl, 3,3', 5,5'-tetra (t -Butyl) -4,4'-dihydroxy-1,1'-biphenyl, 2,2 ', 3,3', 5,5'-hexamethyl-4,4'-dihydroxy-1,1'-biphenyl, 2, , 4′-biphenol, 3,3′-dimethyl-2,4′-dihydroxy-1,1′-biphenyl, 3,3′-di (t-butyl) -2,4′-dihydroxy-1,1 ′ -Biphenyl, 2,2'-biphenol, 3,3'-dimethyl-2,2'-dihydroxy-1,1'-biphenyl, 3,3'-di Biphenol compounds such as t- butyl) -2,2'-dihydroxy-1,1'-biphenyl;
Bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) propane, 1, 1-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) pentane, 3,3-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) -3-methylbutane, 1,1-bis (4-hydroxyphenyl) hexane, 2,2-bis (4- Hydroxyphenyl) hexane, 3,3-bis (4-hydroxyphenyl) hexane, 2,2-bis (4-hydroxyphenyl) -4-methyl Pentane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) bisphenol compounds having no substituents on the aromatic rings such as cyclohexane;
Bis (3-phenyl-4-hydroxyphenyl) methane, 1,1-bis (3-phenyl-4-hydroxyphenyl) ethane, 1,1-bis (3-phenyl-4-hydroxyphenyl) propane, 2,2 A bisphenol compound having an aryl group as a substituent on an aromatic ring such as bis (3-phenyl-4-hydroxyphenyl) propane;
Bis (4-hydroxy-3-methylphenyl) methane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, 1,1-bis (4-hydroxy-3-methylphenyl) propane, 2,2 -Bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane, bis (4-hydroxy-3-ethylphenyl) methane, 1,1-bis (4-hydroxy-3-ethylphenyl) ethane, 1,1-bis (4-hydroxy-3-ethylphenyl) propane, 2,2-bis (4-hydroxy-3-ethylphenyl) propane, 1,1- 2,2-bis (4-hydroxy-3-isopropylphenyl) propane, 2,2-bis (4-hydroxy-3-ethylphenyl) cyclohexane, etc. (4-hydroxy-3- (sec-butyl) phenyl) propane, bis (4-hydroxy-3,5-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) ethane 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, bis (4-hydroxy-3,6-dimethyl) Phenyl) methane, 1,1-bis (4-hydroxy-3,6-dimethylphenyl) ethane, 2,2-bis (4-hydroxy-3,6-dimethylphenyl) propane, bis (4-hydroxy-2, 3,5-trimethylphenyl) methane, 1,1-bis (4-hydroxy-2,3,5-trimethylphenyl) ethane, 2,2-bis (4-hydroxy) -2,3,5-trimethylphenyl) propane, bis (4-hydroxy-2,3,5-trimethylphenyl) phenylmethane, 1,1-bis (4-hydroxy-2,3,5-trimethylphenyl) phenyl A bisphenol compound having an alkyl group as a substituent on an aromatic ring such as ethane or 1,1-bis (4-hydroxy-2,3,5-trimethylphenyl) cyclohexane;
Bis (4-hydroxyphenyl) (phenyl) methane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) -1-phenylpropane, bis (4- Bisphenol compounds in which a divalent group connecting aromatic rings such as hydroxyphenyl) (diphenyl) methane and bis (4-hydroxyphenyl) (dibenzyl) methane has an aryl group as a substituent. In addition, a diol component may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios and combinations.

  Among them, a polycarbonate resin formed from bisphenol or biphenol represented by the following formula [12] is preferably used.

  In particular, a polycarbonate resin formed from bisphenol having a structure represented by the following formula [13] is preferable.

The polycarbonate resin may contain a polycarbonate structure other than that represented by the above formula [11] as a partial structure. Further, the partial structure may include a structure other than the polycarbonate resin.
In said polycarbonate resin, the mass ratio of the partial structure represented by Formula [11] is so preferable that it is large from a viewpoint of an electrical property and abrasion resistance. Specifically, the partial structure represented by the formula [11] is preferably 50% by mass or more, more preferably 70% by mass or more, and further preferably 80% by mass or more with respect to the total mass of the polycarbonate resin. In particular, the content is desirably 100% by mass.

  The viscosity average molecular weight of the binder resin that can be used in combination with the polyarylate resin is arbitrary, but is preferably 10,000 or more, more preferably 20,000 or more, and the upper limit thereof is preferably 70,000 or less, more preferably 50,000 or less. If the value of the viscosity average molecular weight is too small, the mechanical strength of the binder resin may be insufficient, and if it is too large, the viscosity of the coating solution for forming the photosensitive layer may be too high and the productivity may decrease. is there. The viscosity average molecular weight can be measured in the same manner as in the case of the polyarylate resin.

  The usage ratio of the binder resin and the charge transport material used in the charge transport layer of the multilayer photoreceptor and the photosensitive layer of the monolayer photoreceptor is 100 parts by weight of the binder resin in both the single layer and multilayer. The amount of the charge transport material is usually 20 parts by mass or more, preferably 30 parts by mass or more from the viewpoint of reducing the residual potential, more preferably 40 parts by mass or more from the viewpoints of stability during repeated use and charge mobility. From the viewpoint of thermal stability of the photosensitive layer, usually 150 parts by mass or less, from the viewpoint of compatibility between the charge transport material and the binder resin, preferably 120 parts by mass or less, and from the viewpoint of printing durability, more preferably 100 parts by mass. The amount is particularly preferably 80 parts by mass or less from the viewpoint of scratch resistance.

In the case of a single-layer type photoreceptor, a charge generating material described later is further dispersed in the photosensitive layer. In this case, it is important that the particle size of the charge generation material is sufficiently small, and it is preferably 1 μm or less, more preferably 0.5 μm or less.
The amount of the charge generating material used is preferably 0.1% by mass or more, more preferably 1% by mass or more, and the upper limit thereof is preferably 50% by mass or less, more preferably 20% by mass or less. used. If the amount of the charge generating substance used is too small, sufficient sensitivity may not be obtained, and if it is too large, adverse effects such as a decrease in chargeability and a decrease in sensitivity may occur.

  Examples of binder resins that are usually used in charge generation layers in laminated photosensitive layers include polyvinyl butyral resins, polyvinyl formal resins, polyvinyls such as partially acetalized polyvinyl butyral resins in which part of the butyral is modified with formal, acetal, or the like. Acetal resin, polyarylate resin, polycarbonate resin, polyester resin, modified ether polyester resin, phenoxy resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, polystyrene resin, acrylic resin, methacrylic resin, polyacrylamide resin Polyamide resin, polyvinyl pyridine resin, cellulosic resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, casein Vinyl chloride-vinyl acetate such as vinyl chloride-vinyl acetate copolymer, hydroxy-modified vinyl chloride-vinyl acetate copolymer, carboxyl-modified vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, etc. Copolymers, styrene-butadiene copolymers, vinylidene chloride-acrylonitrile copolymers, styrene-alkyd resins, silicone-alkyd resins, phenol-formaldehyde resins and other insulating resins, poly-N-vinylcarbazole, polyvinylanthracene The organic photoconductive polymer such as polyvinyl perylene can be selected and used, but is not limited to these polymers. Moreover, these binder resins may be used alone or in combination of two or more in any ratio and combination.

(Charge generating material)
The charge generation material is usually contained in the single layer type photosensitive layer in the single layer type photosensitive layer, and contained in the charge generation layer in the multilayer type photosensitive layer. Specific examples of the charge generating substance include, for example, selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials, phthalocyanine pigments, azo pigments, dithioketopyrrolopyrrole pigments, squalene pigments, quinacridone pigments, indigo pigments, Various photoconductive materials such as organic pigments such as perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments can be used, and organic pigments, phthalocyanine pigments, and azo pigments are particularly preferable. In addition, a charge generation material may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios and combinations.

  Specific examples of the phthalocyanine used include metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, and other metals, or oxides, halides, hydroxides, and alkoxides thereof. And various crystal forms of coordinated phthalocyanines. In particular, titanyl phthalocyanines (also known as oxytitanium) such as X-type, τ-type metal-free phthalocyanine, A-type (also known as β-type), B-type (also known as α-type), and D-type (also known as Y-type), which are highly sensitive crystal types Phthalocyanine), vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as type V, μ-oxo-gallium phthalocyanine dimer such as type G and I, μ-oxo such as type IIS -Aluminum phthalocyanine dimer is preferred. Among these phthalocyanines, A type (β type), B type (α type), D type (Y type) oxytitanium phthalocyanine, II type chlorogallium phthalocyanine, V type hydroxygallium phthalocyanine, G type μ-oxo- Gallium phthalocyanine dimer and the like are particularly preferable. In particular, oxytitanium phthalocyanine preferably has a clear diffraction peak mainly at a Bragg angle (2θ ± 0.2 °) of 27.3 ° in a powder X-ray diffraction spectrum by CuKα characteristic X-ray.

  The oxytitanium phthalocyanine preferably has a diffraction peak at a Bragg angle (2θ ± 0.2 °) of 9.0 ° to 9.7 ° in a powder X-ray diffraction spectrum by CuKα characteristic X-ray. Moreover, in the said oxytitanium phthalocyanine, it is preferable that the chlorine content in a crystal | crystallization is 1.5 mass% or less. The chlorine content can be determined by elemental analysis, for example.

  Further, in the oxytitanium phthalocyanine crystal, the ratio of the chlorinated oxytitanium phthalocyanine represented by the following formula [14] is higher than the unsubstituted oxytitanium phthalocyanine represented by the following formula [15]. The ratio is 0.070 or less. The mass spectral intensity ratio is preferably 0.060 or less, more preferably 0.055 or less. In the production, when the dry grinding method is used for amorphization, 0.02 or more is preferable, and when the acid paste method is used for amorphization, 0.03 or less is preferable. The amount of chlorine substitution can be measured based on the method disclosed in Japanese Patent Application Laid-Open No. 2001-115054.

  The particle diameter of these oxytitanyl phthalocyanines varies greatly depending on the production method and crystal conversion method, but considering the dispersibility, the primary particle diameter is preferably 500 nm or less, and from the viewpoint of coating film formability, it is preferably 300 nm or less. More preferred. In addition to the chlorine atom, the oxytitanium phthalocyanine may contain various oxytitanium phthalocyanine derivatives substituted with a substituent such as a fluorine atom, a nitro group, a cyano group, or a sulfone group. In addition, these substituents may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios and combinations.

As the azo pigment, various known bisazo pigments and trisazo pigments are preferably used. An example of a preferred azo pigment is shown in the following formula [16]. In Formula ^[16], Cp 1 ~Cp ³ represents a coupler.

Above all, in the formula [16], as the coupler ^Cp 1 ~ CP ^3, preferably each structure shown in the following equation [17].

  By using phthalocyanine and an azo pigment in combination, it is possible to obtain a highly sensitive and ghost-free electrophotographic photoreceptor.

  In the charge generation layer of the laminated photosensitive layer, the mixing ratio of the binder resin and the charge generation material is usually 10 parts by mass or more, preferably 30 parts by mass or more, and the upper limit thereof is 100 parts by mass of the binder resin. Usually 1000 parts by mass or less, preferably 500 parts by mass or less. If the amount used is too small, the sensitivity as an electrophotographic photosensitive member may be lowered, and if too much, the stability of the coating solution may be lowered due to aggregation of charge generating substances. The film thickness is usually 0.1 μm or more, preferably 0.15 μm or more, and the upper limit is usually 4 μm or less, preferably 0.6 μm or less.

  In the case of a multilayer photoreceptor, the charge generation layer can be formed, for example, by applying and drying a charge generation layer forming coating solution in which a charge generation material is dispersed.

  As a method for dispersing the charge generating substance, a known dispersion method such as a ball mill dispersion method, an attritor dispersion method, a sand mill dispersion method, or an ultrasonic dispersion method can be used. At this time, the particles are usually refined to a particle size of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.

(Charge transport material)
The charge transport material is not particularly limited, but the molecular weight of the charge transport material is 250 or more, preferably 300 or more, more preferably 320 or more, particularly preferably 350 or more, and the upper limit thereof is 460 or less, preferably 450 or less. Preferably it is 430 or less, Most preferably, it is 410 or less. If the molecular weight is too small, the charge transport material may sublime during drying after coating, and it may be difficult to control the content of the charge transport material in the photosensitive layer. On the other hand, if the molecular weight is too large, abnormal noise due to rubbing with the cleaning means or the like may easily occur.

  Further, here, a charge transport material having a specific HOMO energy level E_homo by a structure optimization calculation using B3LYP / 6-31G (d, p) as a charge transport material can be used. Specifically, the energy level E_homo of the HOMO is usually −4.67 eV or higher, preferably −4.65 eV or higher, more preferably −4.63 eV or higher, and particularly preferably −4.61 eV or higher.

  The higher the E_homo, the lower the post-exposure potential and the better the electrophotographic photoreceptor. In particular, when a polyarylate resin is used as a binder resin, the post-exposure potential tends to be higher than when a polycarbonate resin is used. Therefore, by setting E_homo within the above range, the effect is remarkable. is there. However, if E_homo is too high, there is a possibility that problems such as a decrease in gas resistance and the occurrence of ghosts may occur, so the upper limit is preferably −4.30 eV or less, more preferably −4.50 eV or less, and particularly preferably Is preferably −4.56 eV or less.

  In the electrophotographic photosensitive member of this embodiment, E_homo is B3LYP (AD Becke, J. Chem. Phys. 98, 5648 (1993), C. Lee, W. Yang, and RG Parr), which is a kind of density functional method. Phys. Rev. B37, 785 (1988) and B. Miehlich, A. Savin, H. Stoll, and H. Preuss, Chem. Phys. Lett. 157, 200 (1989))). It can be obtained by seeking the structure. At this time, 6-31G (d, p) obtained by adding a polarization function to 6-31G was used as the basis function system (R. Ditchfield, WJ Hehre, and JA Pople, J. Chem. Phys. 54, 724 ( 1971), WJ Hehre, R. Ditchfield, and JA Pople, J. Chem. Phys. 56, 2257 (1972), PC Hariharan and JA Pople, Mol. Phys. 27, 209 (1974), MS Gordon, Chem. Phys Lett. 76, 163 (1980), PC Hariharan and JA Pople, Theo. Chim. Acta 28, 213 (1973), J.-P. Blaudeau, MP McGrath, LA Curtiss, and L. Radom, J. Chem. Phys. 107, 5016 (1997), MM Francl, WJ Pietro, WJ Hehre, JS Binkley, DJ DeFrees, JA Pople, and MS Gordon, J. Chem. Phys. 77, 3654 (1982), RC Binning Jr. and LA Curtiss, J. Comp. Chem. 11, 1206 (1990), VA Rassolov, JA Pople, MA Ratner, and TL Windus, J. Chem. Phys. 109, 1223 (1998), and VA Rassolov, MA Ratner, JA Pople , PC Redfern, and LA Curtiss, J. Comp. Chem. 22, 976 (2001)).

Here, the B3LYP calculation using 6-31G (d, p) is described as “B3LYP / 6-31G (d, p)”.
The program used for B3LYP / 6-31G (d, p) calculation is Gaussian 03, Revision D.01 (MJ Frisch, GW Trucks, HB Schlegel, GE Scuseria, MA Robb, JR Cheeseman, JA Montgomery, Jr., T Vreven, KN Kudin, JC Burant, JM Millam, SS Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, GA Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, JE Knox, HP Hratchian, JB Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, RE Stratmann, O. Yazyev, AJ Austin, R. Cammi, C. Pomelli, JW Ochterski, PY Ayala, K. Morokuma, GA Voth, P. Salvador, JJ Dannenberg, VG Zakrzewski, S. Dapprich, AD Daniels, MC Strain, O. Farkas, DK Malick, AD Rabuck, K. Raghavachari, JB Foresman, JV Ortiz, Q. Cui, AG Baboul, S. Clifford , J. Cioslowski, BB Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, RL Martin, DJ Fox, T. Keith, MA Al-Laham, CY Peng, A. Nanayakkara, M. Chall acombe, PMW Gill, B. Johnson, W. Chen, MW Wong, C. Gonzalez, and JA Pople, Gaussian, Inc., Wallingford CT, 2004.).

  When a polyarylate resin is used as the binder resin, the effect of suppressing abnormal noise by setting the CTM molecular weight low can be obtained more remarkably. That is, by combining a polyarylate resin and a charge transport material having the above-described molecular weight and E_homo, there are few cleaning defects, filming, dirt, afterimage (ghost), density reduction, abnormal noise, etc., and excellent wear resistance. A photographic photoreceptor can be obtained. The reason for this is not clear, but a charge transport material having a smaller molecular weight has an effect of improving the slipperiness of the surface of the photoreceptor when combined with a polyarylate resin, and a charge transport material having a high E_homo is applied. This is considered to be because the potential after exposure was made to a practical level. Therefore, the effect of the conductive support described above can be further increased, and an electrophotographic photosensitive member that additionally exhibits other effects can be obtained.

  As the charge transport material, any compound can be used as long as it has the molecular weight and E_homo described above. Specific examples of the charge transport material include enamine derivatives, carbazole derivatives, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, and a combination of these compounds. In addition, a charge transport substance may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios and combinations.

  Moreover, as a charge transport material having the above molecular weight and E_homo, a stilbene derivative is preferable, and a typical example of the stilbene derivative includes a compound represented by the following formula [18]. However, the stilbene derivative is not limited to these compounds. These stilbene derivatives may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios and combinations.

  In addition, as the charge transport material having the above molecular weight and E_homo, a charge transport material represented by the following formula [19] is particularly preferable.

In formula [19], R ^{1 to} R ⁴ each independently represent a hydrogen atom, an alkyl group that may have a substituent, or an aryl group that may have a substituent, and R ⁵ represents a substituent. Represents an aryl group that may have a substituent, or an aryl group that may have a substituent, n represents an integer of 0 or more and 3 or less, and ring Z is a saturated group formed together with two carbon atoms of the indoline ring. Two hydrogen atoms representing a 5- to 8-membered ring and present on the two carbon atoms are in the cis configuration.
R ^{1 to} R ⁴ each independently represent a hydrogen atom, an alkyl group that may have a substituent, or an aryl group that may have a substituent, and R ⁵ may have a substituent. An alkyl group or an aryl group which may have a substituent is represented.

When R ^{1 to} R ⁵ are alkyl groups, the alkyl group has any number of carbon atoms, but is 1 to 10, preferably 6 or less, more preferably 3 or less. When there are too many carbon numbers, an electrical property may deteriorate. Specific examples of the alkyl group include a methyl group, an ethyl group, and a propyl group.

When R ^{1 to} R ⁵ are aryl groups, the aryl group has any number of carbon atoms, but is 6 or more and 14 or less, preferably 13 or less, and more preferably 10 or less. When there are too many carbon numbers, an electrical property may deteriorate. Specific examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a fluorenyl group. Among these, in consideration of the characteristics of the electrophotographic photoreceptor, a phenyl group and a naphthyl group are preferable, and a phenyl group is particularly preferable.

Moreover, as a substituent which said alkyl group and aryl group may have, it is arbitrary, For example, an alkyl group, an aryl group, an alkoxy group, an aryloxy group etc. are mentioned. In addition, as for a substituent, 1 type may be substituted independently and 2 or more types may be substituted by arbitrary ratios and combinations.
Among the above, R ¹ is preferably an aryl group which may have a substituent, and more preferably an aryl group having a substituent.

The substituent that the aryl group has is preferably an alkyl group such as a methyl group, an ethyl group, or a propyl group; an alkoxy group such as a methoxy group, an ethoxy group, or a propoxy group; among them, an alkyl group or a methoxy group is more preferable, and a methyl group is preferable. Particularly preferred. That is, it is particularly preferable that R ¹ is a p-tolyl group because of a good balance of electrical characteristics. By using a p-tolyl group, E_homo can be set high and preferable electrical characteristics can be easily obtained.

R ² is preferably a hydrogen atom or an alkyl group which may have a substituent, and a hydrogen atom is preferred from the viewpoint of ease of production.
As R ³ and R ⁴ , an alkyl group which may have a substituent or an aryl group which may have a substituent is preferable, and from the viewpoint of electrical characteristics, an aryl group which may have a substituent among them Is preferred.

As the aryl group, a phenyl group is preferable. As the substituent that the aryl group has, an alkyl group such as a methyl group, an ethyl group, or a propyl group, or an alkoxy group such as a methoxy group, an ethoxy group, or a propoxy group is preferable, an alkyl group or a methoxy group is more preferable, and a methyl group is preferable. Further preferred.
However, among the above, an unsubstituted phenyl group is particularly preferable.

R ⁵ is preferably an unsubstituted state (that is, n = 0) or an alkyl group that may have a substituent, and an unsubstituted state is preferable from the viewpoint of production.
n is an integer of 0 or more and 3 or less, and n = 0 is particularly preferable.
Ring Z represents a saturated 5-8 membered ring formed with the two carbon atoms of the indoline ring.
Among these, from the viewpoint of ease of production, the ring Z is preferably a 5- or 6-membered ring, and a 5-membered ring is particularly preferable. Two hydrogen atoms existing on two carbon atoms shared by the ring Z and the indoline ring can have a cis configuration or a trans configuration. According to the study by the present inventors, it has been found that the trans configuration causes distortion in the five-membered ring and the E_homo is low, whereas the cis configuration has a high E_homo, and favorable electrical characteristics can be obtained.

An example of E_hom of cis arrangement and trans arrangement is shown below in Expression [20] and Expression [21]. E_homo of the cis arrangement in the equation [20] is −4.61 (eV), and E_homo of the trans arrangement in the expression [21] is −4.73 (eV).
However, the compounds shown below are examples of charge transport materials, and applicable charge transport materials in electrophotographic photoreceptors are not limited thereto.

  Specific examples of the compound represented by the formula [19] are shown below in the formula [22] and the formula [23].

  The charge transport material having the molecular weight and E_homo may be used in combination with the charge transport material not satisfying the ranges of the molecular weight and E_homo. However, in order to exert the above-described effects greatly, In the charge transport material, the amount of the charge transport material is usually 30% by mass or more, preferably 50% by mass or more, more preferably 80% by mass or more, and particularly preferably 100% by mass.

  In addition, the charge transport material having the above molecular weight and E_homo exerts the above-described effects greatly, so that it is usually 30 parts by mass or more, preferably 40 parts by mass or more, more preferably 50 parts by mass with respect to 100 parts by mass of the binder resin. The upper limit thereof is preferably 120 parts by mass or less, more preferably 100 parts by mass or less, and particularly preferably 80 parts by mass or less.

In addition, when the charge transport material having the molecular weight and E_homo is contained in the photosensitive layer together with the polyarylate resin, it can exhibit particularly excellent wear resistance and electrical characteristics.
Table 1 below shows specific examples of the charge transport material together with the molecular weight and E_homo. “Me” represents a methyl group.

  As other charge transport materials, charge transport materials outside the range of the molecular weight or E_homo described above may be used in combination, or may be used alone. Examples of such charge transport materials include aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, electron withdrawing materials such as quinone compounds such as diphenoquinone, carbazole Derivatives, indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, thiadiazole derivatives, benzofuran derivatives and other heterocyclic compounds, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives, and An electron donating substance such as a polymer in which a plurality of types are bonded, or a polymer having a group consisting of these compounds in the main chain or side chain is exemplified. Among these, carbazole derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, hydrazone derivatives, enamine derivatives, and those in which a plurality of these compounds are bonded are preferable. One of these charge transport materials may be used alone, or two or more thereof may be used in any ratio and combination.

  Preferred specific examples of other charge transport materials are shown in Formula [24] to Formula [26]. In the following compounds, R may be the same or different. Specifically, a hydrogen atom, an alkyl group, an alkoxy group, a phenyl group, an arylalkyl and the like are preferable. Particularly preferred is a methyl group, an ethyl group or a benzyl group. N is an integer of 0 or more and 2 or less.

  The following examples are specific examples of the charge transport material, and other charge transport materials are not limited to the following.

  Further, as other charge transporting materials, it is preferable to use the compounds listed in the following formula [27] among the above.

(Other components contained in the photosensitive layer)
In addition, the photosensitive layer has, for example, an antioxidant, a plasticizer, an ultraviolet absorber, an electron withdrawing property in order to improve film forming property, flexibility, coating property, stain resistance, gas resistance, light resistance, and the like. You may contain additives, such as a compound, a leveling agent, a visible light shading agent, and a sensitizer. An additive may be used individually by 1 type and may be used 2 or more types by arbitrary ratios and combinations.

Examples of the antioxidant include hindered phenol compounds and hindered amine compounds. Examples of dyes and pigments include various pigment compounds and azo compounds. Examples of leveling agents include silicone oil and fluorine-based oil.
Examples of the hindered phenol antioxidant include 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-ethylphenol, and 2,6-di-t-butyl-4-methyl. Phenol, 2,2′-methylenebis (6-tert-butyl-4-methylphenol), 4,4′-butylidenebis (6-tert-butyl-3-methylphenol), 4,4′-thiobis (6-t -Butyl-3-methylphenol), 2,2′-butylidenebis (6-tert-butyl-4-methylphenol), α-tocopherol, β-tocopherol, 2,2,4-trimethyl-6-hydroxy-7- t-butylchroman, pentaerythrityltetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2′-thioethylenebis [3- (3 5-di-t-butyl-4-hydroxyphenyl) propionate], 1,6-hexanediol bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], butylhydroxyanisole, dibutyl Hydroxyanisole, 1- [2-{(3,5-di-butyl-4-hydroxyphenyl) propionyloxy} ethyl] -4- [3- (3,5-di-butyl-4-hydroxyphenyl) propionyloxy ] -2,2,6,6-tetramethylpiperazyl, 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5 Triazine, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 2- (5-methyl- -Hydroxyphenyl) benzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 1- [2- {3- (3,5-di-t-butyl) -4-hydroxyphenyl) propionyloxy} ethyl] -4- {3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy} -2,2,6,6-tetramethylpiperidine, n -Octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, etc. can be mentioned.

  Among them, those having one or more t-butyl groups on the phenol ring in the molecule are preferable, and among them, those in which the t-butyl group is bonded to the position adjacent to the phenolic hydroxyl group (that is, in the ortho position with respect to the hydroxyl group). Those having a t-butyl group bonded thereto are more preferred. Among them, those in which two t-butyl groups are bonded at positions adjacent to the phenolic hydroxyl group (that is, those in which t-butyl groups are bonded at positions 2 and 6 with respect to the hydroxyl group) are particularly preferable. . Specific examples thereof include 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-ethylphenol, 2,6-di-t-butyl-4-methylphenol, and n-octadecyl. Monophenolic antioxidants such as -3- (4'-hydroxy-3 ', 5'-di-t-butylphenyl) propionate, 2,2'-methylenebis (6-t-butyl-4-methylphenol) 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, pentaerythrityltetrakis [3- (3,5-di-t- Polyphenolic antioxidants such as butyl-4-hydroxyphenyl) propionate] are preferred. By using these, an electrophotographic photoreceptor free from fogging can be easily produced even when used repeatedly.

  Moreover, in order to improve acid-proof gas resistance, it is possible to use the alkylamine compound which may have a well-known substituent. For example, it is preferable to use compounds disclosed in JP-A-3-172852, JP-A-2007-52408, and the like. Among these, for example, tribenzylamine can be preferably used.

(Method for forming photosensitive layer)
Each layer constituting the photoconductor is usually applied sequentially by applying a coating solution containing the material constituting each layer on the conductive support using a known coating method, repeating the coating and drying steps for each layer. Is formed.

  Solvents used for the preparation of coating solutions and dispersion media for dissolving the binder resin include, for example, saturated aliphatic solvents such as pentane, hexane, octane and nonane, aromatic solvents such as toluene, xylene and anisole, chlorobenzene, Halogenated aromatic solvents such as dichlorobenzene and chloronaphthalene, amide solvents such as dimethylformamide and N-methyl-2-pyrrolidone, alcohol solvents such as methanol, ethanol, isopropanol, n-butanol and benzyl alcohol, glycerin, Aliphatic polyhydric alcohols such as polyethylene glycol, chain, branched and cyclic ketone solvents such as acetone, cyclohexanone, methyl ethyl ketone, 4-methoxy-4-methyl-2-pentanone, methyl formate, ethyl acetate, n-butyl acetate Ester-based solvents such as , Halogenated hydrocarbon solvents such as methylene chloride, chloroform, 1,2-dichloroethane, diethyl ether, dimethoxyethane, tetrahydrofuran (hereinafter referred to as “THF” as appropriate), 1,4-dioxane, methyl cellosolve, ethyl Linear and cyclic ether solvents such as cellosolve, aprotic polar solvents such as acetonitrile, dimethyl sulfoxide, sulfolane, hexamethylphosphoric triamide, n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine, triethylenediamine, Examples thereof include nitrogen-containing compounds such as triethylamine, mineral oil such as ligroin, water and the like, and those which do not dissolve the above-described undercoat layer are preferably used. In addition, these may be used individually by 1 type and may be used 2 or more types by arbitrary ratios and combinations.

  The coating solution for forming the photosensitive layer has a solid content concentration of usually 5% by mass or more, preferably 10% by mass or more, and its upper limit in the case of a single layer type photosensitive layer and a charge transport layer of a laminated type photosensitive layer. Is usually 40% by mass or less, preferably 35% by mass or less. Further, the viscosity of the coating solution is usually 10 mPa · s or more, preferably 50 mPa · s or more, and the upper limit thereof is usually 500 mPa · s or less, preferably 400 mPa · s or less.

  In the case of the charge generation layer of the multilayer photosensitive layer, the solid content concentration is usually 0.1% by mass or more, preferably 1% by mass or more, and the upper limit is usually 15% by mass or less, preferably 10% by mass. It is as follows. The viscosity of the coating solution is usually 0.01 mPa · s or more, preferably 0.1 mPa · s or more, and the upper limit is usually 20 mPa · s or less, preferably 10 mPa · s or less.

  Examples of the coating method for the coating liquid include dip coating, spray coating, spinner coating, bead coating, wire bar coating, blade coating, roller coating, air knife coating, and curtain coating. However, other known coating methods can be used. In addition, these methods may be used individually by 1 type, and may be used in combination of 2 or more types arbitrarily.

The coating solution can be dried by touching at room temperature (usually 25 ° C.), followed by heating and drying in the temperature range of usually 30 ° C. or more and 200 ° C. or less, usually for 1 minute or more and 2 hours or less, without wind or air. preferable. The heating temperature may be constant or may be changed while drying.
The film thickness of the single-layer type photosensitive layer is usually 5 μm or more, preferably 10 μm or more, and the upper limit is usually 100 μm or less, preferably 50 μm or less.

  The thickness of the charge transport layer of the multilayer photosensitive layer is usually in the range of 5 μm to 50 μm, but from the viewpoint of long life and image stability, preferably from 10 μm to 45 μm, from the viewpoint of high resolution. Is more preferably 10 μm or more and 30 μm or less.

[Protective layer, etc.]
A protective layer may be provided on the outermost surface layer of the photosensitive layer for the purpose of preventing the photosensitive layer from being worn or preventing or reducing deterioration of the photosensitive layer due to a discharge substance generated from a charger or the like. The protective layer is formed, for example, by containing a conductive material in an appropriate binder resin, or a co-layer using a compound having a charge transporting capability such as a triphenylamine skeleton as described in JP-A-9-190004. A polymer can be used. Examples of the conductive material include aromatic amino compounds such as TPD (N, N′-diphenyl-N, N′-bis- (m-tolyl) benzidine), antimony oxide, indium oxide, tin oxide, titanium oxide, and tin oxide. -Metal oxides such as antimony oxide, aluminum oxide, and zinc oxide can be used, but are not limited thereto. In addition, these may be used individually by 1 type and may be used 2 or more types by arbitrary ratios and combinations.

  As the binder resin used for the protective layer, for example, a known resin such as polyamide resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polyvinyl ketone resin, polystyrene resin, polyacrylamide resin, or siloxane resin may be used. In addition, as described in JP-A-9-190004, a copolymer of a skeleton having a charge transporting ability such as a triphenylamine skeleton and the above resin can also be used. In addition, binder resin used for a protective layer may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios and combinations.

The protective layer is preferably formed so that the electric resistance is usually 10 ⁹ Ω · cm or more and 10 ¹⁴ Ω · cm or less. If the electrical resistance is too small, the image may be blurred or the resolution may be reduced. If the electrical resistance is too large, the residual potential may increase and an image with much fog may be formed. In addition, the protective layer is preferably formed so as not to substantially prevent transmission of light irradiated for image exposure.

  In addition, for example, for the purpose of reducing the frictional resistance and wear on the surface of the electrophotographic photosensitive member, and increasing the transfer efficiency of the toner from the electrophotographic photosensitive member to the transfer belt and paper, the surface layer is made of a fluorine resin, silicone resin, polyethylene Resin, polystyrene resin, etc. may be included. Further, the surface layer may contain particles made of these resins, particles of an inorganic compound, and the like.

[Physical properties of electrophotographic photosensitive member 3]
The elastic deformation rate of the surface of the electrophotographic photosensitive member in this embodiment is usually 44.0% or more, preferably 45.0% or more, more preferably 46.0% or more. Moreover, the upper limit is 60.0% or less normally, Preferably it is 50.0% or less. As the elastic deformation rate is larger, the scratch resistance of the photosensitive layer is improved, and filming caused by pressing silica or the like used as an external additive of the toner against the cleaning blade tends to be improved. However, if the elastic deformation rate is too large, there is a possibility that a rubbing noise with the cleaning blade is likely to occur.

Further, the universal hardness in the present embodiment is usually 180 N / mm ² or more, preferably 200 N / mm ² or more, more preferably 210N / mm ² or more, and the upper limit thereof is usually 300N / mm ² or less, preferably 270N / mm ² or less, more preferably 240 N / mm ² or less.

The elastic deformation rate and the universal hardness are values measured under an environment of a temperature of 25 ° C. and a relative humidity of 50% using a microhardness meter FISHERSCOPE H100C manufactured by Fischer. For the measurement, a Vickers square pyramid diamond indenter having a facing angle of 136 ° is used. The measurement conditions are set as follows, the load applied to the indenter and the indentation depth under the load are continuously read, and profiles as shown in FIG. 2 plotted on the Y axis and the X axis are obtained.
・ Measurement conditions Maximum indentation load 5mN
Load required time 10 seconds Unloading required time 10 seconds The above elastic deformation rate is a value defined by the following formula, and the work performed by the film due to elasticity at the time of unloading with respect to the total work required for indentation. It is a ratio.

Elastic deformation rate (%) = (We / Wt) × 100
Here, the total work Wt (nJ) indicates the area surrounded by A-B-D-A in FIG. 2, and the elastic deformation work We (nJ) indicates the area surrounded by C-B-D-C. Show. As the elastic deformation rate is larger, the deformation with respect to the load is less likely to remain, and when the elastic deformation rate is 100, it means that no deformation remains.

Moreover, said universal hardness is a value when it pushes in to indentation load 5mN, and is a value defined by the following formula | equation from the indentation depth at that time.
Universal hardness (N / mm ² ) = Test load (N) / Vickers indenter surface area under test load (mm ² )
By using the above polyarylate resin as the polyarylate resin, the above elastic modulus and universal hardness can be easily obtained.

<Charging means 4>
The charging means 4 is a means for charging the electrophotographic photoreceptor 3 and uniformly charges the surface of the electrophotographic photoreceptor 3 to a predetermined potential. As a charging means, a corona charging device such as corotron or scorotron, a direct charging device (contact type charging device) that makes a direct charging member to which a voltage is applied contact the surface of the photosensitive member for charging, a contact type charging device such as a charging brush, etc. Is often used. Examples of direct charging means include contact chargers such as charging rollers and charging brushes. In FIG. 1, a roller type charging device (charging roller) is shown as an example of the charging unit 4. As the direct charging means, either charging with air discharge or injection charging without air discharge is possible. Moreover, as a voltage applied at the time of charging, it is possible to use only a direct current voltage or to superimpose alternating current on direct current.

<Exposure means 5>
The exposure device 5 is means for exposing the electrophotographic photosensitive member 3 to form an electrostatic latent image on the photosensitive surface of the electrophotographic photosensitive member 3. If it has such a function, there will be no restriction | limiting in particular in the kind. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, LEDs, and the like. Further, exposure may be performed by a photoreceptor internal exposure method.
The light used for the exposure is arbitrary. For example, if exposure is performed with monochromatic light with a wavelength of 780 nm, monochromatic light with a wavelength of 600 nm to 700 nm, slightly shorter wavelength, monochromatic light with a wavelength of 380 nm to 500 nm, or the like. Good. Among these, it is preferable to use light having a short wavelength of 380 to 500 nm because the resolution becomes high. Among these, 405 nm monochromatic light is preferable. Moreover, the writing resolution is mainly 600 dpi or more at present, but there is a high-performance model having 1200 dpi. The resolution of the electrostatic latent image and the toner image is determined depending on the writing resolution, and the higher the resolution, the clearer the image is obtained. Therefore, a resolution of 1200 dpi or higher is preferable. For example, when writing is performed with an LED having a resolution of 600 dpi and 1200 dpi, the minimum dot formation interval is 42 μm and 21 μm, respectively.

<Developing means 6>
The developing means 6 is a so-called developing means. There are no particular restrictions on the type of developing means that can be applied here, and any device such as a cascade development, a one-component insulating toner development, a one-component conductive toner development, a two-component magnetic brush development, or a dry development method or a wet development method can be used. Can be used.
In the present embodiment, the developing unit 6 includes a developing tank 61, an agitator 62, a supply roller 63, a developing roller 64, and a regulating member 65. Further, if necessary, a replenishing device (not shown) for replenishing toner may be attached to the developing means 6. This replenishing device is configured to be able to replenish toner from containers such as bottles and cartridges.

  The developing tank 61 is a means for forming the outline of the developing means, and contains each component member and toner inside.

  The agitator 62 is means for stirring the toner and conveying the toner to the supply roller 63 side. Therefore, the agitator 62 includes a blade-like member that is rotated by a rotation drive mechanism. The blade shape and the size thereof are not particularly limited and are appropriately designed to exhibit the function.

  The supply roller 63 is a means for carrying the stored toner and supplying it to the developing roller 64, and is formed of a conductive sponge or the like.

The developing roller 64 is rotated by a rotation driving mechanism (not shown), carries the toner supplied by the supply roller 63, and has a function of bringing the toner into contact with the surface of the electrophotographic photosensitive member 3. Accordingly, the developing roller 64 is disposed between the electrophotographic photosensitive member 3 and the supply roller 63 and is in contact with the electrophotographic photosensitive member 3 and the supply roller 63, respectively.
Such a developing roller 64 can be constituted by a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicone resin, a urethane resin, a fluorine resin, or the like. Further, the surface of the developing roller 64 may be smoothed or roughened as necessary.

  The restricting member 65 is a member having a function of adjusting the amount of toner attached to the outer peripheral surface of the developing roller 64. Therefore, the regulating member 65 is formed of a resin blade such as a silicone resin or a urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such a metal blade with a resin. The regulating member 65 contacts the developing roller 64 and is pressed with a predetermined force against the developing roller 64 by a spring or the like (a general blade linear pressure is 5 to 500 g / cm). Further, if necessary, the regulating member 65 may be provided with a function of imparting charging to the toner by frictional charging with the toner.

<Transfer means 7>
The transfer unit 7 has a function of applying a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner, and transferring the toner image formed on the electrophotographic photosensitive member 3 to the recording paper (paper, medium) P. I have it. There are no particular restrictions on the type of transfer means that can be used here, and an apparatus using any method such as electrostatic transfer methods such as corona transfer, roller transfer, and belt transfer, pressure transfer method, and adhesive transfer method should be used. Can do.

<Cleaning means 8>
The cleaning unit 8 is a unit that scrapes the residual toner adhering to the electrophotographic photosensitive member 3 with a cleaning member and collects the residual toner. The type of cleaning means that can be applied here is not particularly limited, and any cleaning device such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, or a blade cleaner can be used. If there is little or almost no toner remaining on the surface of the photoreceptor, the cleaning means may not be provided.

  Among these, the blade cleaning method is preferable because of its simple structure, small size, low cost, and excellent cleaning performance and reliability. In particular, when toner having a high degree of circularity is used, the counter contact method is preferable because the toner easily slips between the blade and the photoreceptor. The linear pressure of the blade against the photoreceptor is preferably set to 20 to 60 g / cm.

  In addition, when an electrophotographic photosensitive member having an outer diameter of 20 mm or less is used, the linear pressure of the cleaning blade may be set to be particularly strong. It is preferable to apply a lubricant to the part. Examples of the lubricant include toner, polytetrafluoroethylene, polypropylene, and silicone resin.

<Fixing means 9>
The fixing unit 9 includes an upper fixing member (fixing roller) 91 and a lower fixing member (fixing roller) 92, and a heating device 93 is provided inside the upper fixing member 91 or the lower fixing member 92. FIG. 1 shows an example in which a heating device 93 is provided inside the upper fixing member 91. The upper and lower fixing members 91 and 92 are a fixing roll in which a metal conductive support such as stainless steel or aluminum is coated with silicone rubber, a fixing roll coated with Teflon (registered trademark) resin, a fixing sheet, and the like. A known heat fixing member can be used. Further, each of the fixing members 91 and 92 may be configured to supply a release agent such as silicone oil in order to improve releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

  When the toner transferred onto the recording paper P passes between the upper fixing member 91 and the lower fixing member 92 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P. The type of fixing means is not particularly limited, and other fixing means such as heat roller fixing, flash fixing, oven fixing, and pressure fixing may be applied, including those used here.

<< Image forming apparatus >>
The image forming apparatus has an image forming apparatus main body and the above-described electrophotographic cartridge 1 incorporated in the image forming apparatus main body. Examples of the image forming apparatus include a laser printer, a copying machine, and a facsimile.

  The main body of the image forming apparatus is a main part of the image forming apparatus. The image forming apparatus main body includes a rotary drive shaft and a bearing for driving the electrophotographic cartridge 1, and various apparatuses for appropriately operating the electrophotographic cartridge 1. I have. In addition, the image forming apparatus includes various devices necessary for forming an image.

  In addition, the image forming apparatus main body is configured to be able to perform processes such as a pre-exposure process and an auxiliary charging process, to be configured to perform offset printing, and to a full color tandem system using a plurality of types of toner. It is good also as a structure.

  The electrophotographic cartridge 1 may be configured to be detachable from the image forming apparatus main body. In this case, for example, when a member included in the electrophotographic cartridge 1 is deteriorated, the electrophotographic cartridge is removed from the main body of the image forming apparatus, and another new electrophotographic cartridge is attached to the main body of the image forming apparatus. Maintenance and management of the system becomes easy.

<< Image recording by image forming apparatus >>
In the image forming apparatus configured as described above, focusing on the part of the electrophotographic cartridge 1, for example, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the electrophotographic photosensitive member 3 is charged to a predetermined potential (for example, −600 V) by the charging unit 4. At this time, charging may be performed with a DC voltage, or charging may be performed by superimposing an AC voltage on the DC voltage.
Subsequently, the charged photosensitive surface of the electrophotographic photosensitive member 3 is exposed by the exposure means 5 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. The developing means 6 develops the electrostatic latent image formed on the photosensitive surface of the electrophotographic photosensitive member 3.

The developing means 6 thins the toner supplied by the supply roller 63 with a regulating member (developing blade) 65 and has a predetermined polarity (here, the same polarity as the charging potential of the electrophotographic photosensitive member 3) and the negative electrode The toner is conveyed while being carried on the developing roller 64 and brought into contact with the surface of the electrophotographic photosensitive member 3.
When the charged toner carried on the developing roller 64 contacts the surface of the electrophotographic photoreceptor 3, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the electrophotographic photoreceptor 3. This toner image is transferred onto the recording paper P by the transfer means 7. Thereafter, the toner remaining on the photosensitive surface of the electrophotographic photosensitive member 3 without being transferred is removed by the cleaning means 8.

  After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing means 9 and thermally fixing the toner image onto the recording paper P.

  In addition to the above-described configuration, the image forming apparatus may have a configuration capable of performing a static elimination process, for example. The neutralization step is a step of neutralizing the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member, and a fluorescent lamp, LED, or the like is used as the neutralizing unit. In addition, the light used in the static elimination process is often light having an exposure energy that is at least three times that of the exposure light.

  In such an image recording operation, the electrophotographic photosensitive member 3 rotates about its axis. However, according to the present invention, it is possible to suppress the occurrence of vibrations and abnormal sounds accompanying the rotation.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. Here, what is described as “parts” means “parts by mass”.

<Electrophotographic Photosensitive Member of Example 1>
[Conductive support]
For the conductive support of Example 1, an aluminum alloy cylinder having an outer diameter of 24 mm, a length of 246 mm, and a wall thickness of 0.71 mm was used. The outer surface was finished by cutting to obtain a surface with Ry = 0.75 μm. The following was used for the conductive support in Example 1.
-Al: 93.40 mass%
・ Si: 0.04 mass%
・ Ti: 0.02 mass%
-Fe: 0.28 mass%
Ga: 0.01% by mass
・ Ba: 0.04 mass%
・ Ni: 5.69 mass%
・ La: 0.15 mass%
-Ce: 0.29 mass%
・ Pr: 0.03 mass%
・ Nd: 0.08 mass%

Here, the conductive support of Example 1, Al-Ni crystallizate 0.0417 pieces / [mu] m ^2, Al- earth crystallizate was 0.0085 pieces / [mu] m ^2. A specific evaluation method will be described later.

  The undercoat layer forming coating solution, the charge generation layer forming coating solution, and the charge transport layer forming coating solution shown below are sequentially applied to the conductive support as described above by a dip coating method and dried. An undercoat layer, a charge generation layer, and a charge transport layer were formed to have thicknesses of 1.5 μm, 0.3 μm, and 25 μm, respectively, to obtain an electrophotographic photosensitive member.

[Coating liquid for undercoat layer formation]
The undercoat layer forming coating solution was prepared as follows. Rutile type titanium oxide having an average primary particle diameter of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by mass of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide were mixed using a Henschel mixer. The surface-treated titanium oxide obtained by mixing was dispersed by a ball mill in a mixed solvent having a mass ratio of methanol / 1-propanol of 7/3 to obtain a surface-treated titanium oxide dispersed slurry. The dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam (a compound represented by the following formula [28]) / bis (4-amino-3-methylcyclohexyl) methane (the following formula [29 ] / Hexamethylenediamine (compound represented by the following formula [30]) / decamethylene dicarboxylic acid (compound represented by the following formula [31]) / octadecamethylene dicarboxylic acid (compound represented by the following formula [32]) The polyamide pellets were dissolved by stirring and mixing the copolymerized polyamide pellets having a composition molar ratio of 60% / 15% / 5% / 15% / 5% with heating. Thereafter, by performing ultrasonic dispersion treatment, the solid content concentration containing methanol / 1-propanol / toluene in a mass ratio of 7/1/2 and surface-treated titanium oxide / copolymerized polyamide in a mass ratio of 3/1. A coating solution for forming an undercoat layer of 18.0% was prepared.

[Coating liquid for charge generation layer formation]
The charge generation layer forming coating solution was prepared as follows. As a charge generation material, 20 parts of oxytitanium phthalocyanine shown in the X-ray diffraction spectrum of FIG. 3 and 280 parts of 1,2-dimethoxyethane were mixed, and pulverized with a sand grind mill for 1 hour to carry out atomization dispersion treatment. Subsequently, 10 parts of polyvinyl butyral (trade name “Denkabutyral” # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.) were added to this treatment solution, 255 parts of 1,2-dimethoxyethane and 4-methoxy-4-methyl-2. -A binder liquid obtained by dissolving in 85 parts of a mixed solution of pentanone and 230 parts of 1,2-dimethoxyethane were mixed to prepare a coating solution for forming a charge generation layer.

[Coating liquid for charge transport layer formation]
100 parts of a polyarylate resin represented by a repeating structure of the following formula [33] (resin 1, viscosity average molecular weight 40000), 50 parts of CTM1 represented by the following formula [34] as a charge transport material, and the following as an antioxidant 4 parts of the compound represented by the formula [35] (AOX1) and 0.05 part of dimethylpolysiloxane (KF96-10CS manufactured by Shin-Etsu Chemical Co., Ltd.) are dissolved in 640 parts of a tetrahydrofuran / toluene (8/2 (mass ratio)) mixed solvent. Thus, a coating solution for forming a charge transport layer was prepared.

<Electrophotographic Photosensitive Member of Example 2>
In the electrophotographic photoreceptor of Example 2, the same conductive support as in Example 1 was used, and the resin of formula [34] used in the charge transport layer forming coating solution of Example 1 was replaced by the following formula [37]. An electrophotographic photosensitive film was prepared in the same manner as in Example 1 except that a coating liquid for forming a charge transport layer was prepared by changing to a polycarbonate resin represented by a repeating structure (resin 2, viscosity average molecular weight 40000) and a charge transport layer was formed. The body was made.

<Electrophotographic Photosensitive Member of Comparative Example 1>
In the electrophotographic photosensitive member of Comparative Example 1, the conductive support used in Examples 1 and 2 does not contain Ni and rare earth elements, and the electrophotographic photosensitive member is the same as Example 2 except for the conductive support. The body was made. The component not containing Ni and rare earth elements increased the Al component.

<Evaluation method>
[Evaluation of the number of crystals]
The number of Al-Ni crystallized substances and Al-rare earth crystallized substances in the conductive support was determined as follows.
(apparatus)
For the number evaluation, a HITACHI / S-3400N scanning electron microscope and a Thermo / NSS UltraDry energy dispersive X-ray analyzer were used.
(Measurement condition)
Pressure condition: 20kV
Detector: Backscattered electron detector Observation mode: Composition image Observation particle: Count the number of particles having an area of 0.45 μm ² or more.
Observation area: 0.0432 mm ²
(Here, one visual field area is 0.0108 m ² , and 0.0108 mm ² × 4 = 0.0432 mm ² can be obtained by performing four visual fields.)
Magnification: 500 times

  The vibrations and abnormal noises of the electrophotographic photosensitive members of Examples 1 and 2 and Comparative Example 1 described above were evaluated by actual machine evaluations and model tests. Details are as follows.

[Evaluation of actual machine]
In the actual machine evaluation, a printer (IPSiO SP C220, manufactured by Ricoh Co., Ltd.) was used, and the electrophotographic photosensitive member provided in the cyan toner cartridge was replaced with the electrophotographic photosensitive member of Examples 1, 2 and Comparative Example 1 described above. Measurements were made. An image pattern with a printing density of 1% was printed on 1600 sheets intermittently in plain paper mode.
After the printing of 1600 sheets, the sound was checked in the cardboard mode, and the time until the 3300 Hz sound was attenuated by the acceleration sensor was quantitatively measured. The environment at this time was an ambient temperature of 32 ° C. and a relative humidity of 54%.

[Model test]
In the model test, the cyan toner cartridge used in the actual machine evaluation was used, and evaluation was performed by applying the electrophotographic photoreceptors of Example 2 and Comparative Example 1 to the same as in the actual machine evaluation. Specifically, after the electrophotographic photosensitive member was mounted on the cartridge, an AC voltage was applied, and the amplitude of vibration perpendicular to the rotation axis direction of the electrophotographic photosensitive member was measured with an acceleration sensor. The AC voltage was applied in three conditions of a frequency of 830 Hz, 1000 Hz, and 1100 Hz at a voltage of −700 V to +700 V.

<Evaluation results>
Table 2 shows the evaluation results.

As shown in Table 2, in Examples 1 and 2 using a conductive support in which Al-Ni crystallized substances and Al-rare earth crystallized crystals are crystallized, the generated sound is reduced compared to Comparative Example 1. I was able to. This can be quantitatively grasped from the decay time by the acceleration sensor.
Further, in Example 1 in which the charge transport layer forming coating solution contains a polyarylate resin, generation of sound could be further suppressed as compared with Example 2 in which a polycarbonate resin was used here.

  On the other hand, in Example 2 using a conductive support containing any of the rare earth elements La, Ce, Pr, and Nd from the model test, the amplitude of vibration due to application of the AC voltage is smaller than that in Comparative Example 1, and the sound is reduced. It was found that the occurrence of

  The present invention can be used in any field where an electrophotographic photosensitive member is used, and is particularly suitable for use in an image forming apparatus such as a printer or a copying machine.

DESCRIPTION OF SYMBOLS 1 Electrophotographic cartridge 2 Housing 3 Electrophotographic photosensitive member 4 Charging means (charging roller)
5 Exposure means 6 Development means 7 Transfer means 8 Cleaning means 9 Fixing means

Claims (7)

A conductive support used for an electrophotographic photoreceptor,
Aluminum mainly composed of aluminum, containing at least one of nickel and rare earth elements, and aluminum per unit area when the surface of the conductive support is observed with a scanning electron microscope magnified 500 times The average number of at least one of an intermetallic compound based on aluminum and nickel and an intermetallic compound based on aluminum and rare earth elements is 0.005 / μm ² or more and 0.1 μm ² or less. Conductive support.   The conductive support according to claim 1, wherein the rare earth element is at least one element selected from the group consisting of lanthanum, cerium, praseodymium, and neodymium.   An electrophotographic photosensitive member in which a photosensitive layer having a charge generation function and a charge transport function is formed on the surface of the conductive support according to claim 1.   The electrophotographic photosensitive member according to claim 3, comprising a polyarylate resin as a binder resin of the photosensitive layer. The electrophotographic photosensitive member according to claim 4, wherein the polyarylate resin contains a repeating unit represented by the following formula [1].

(In the formula [1], Ar ^{1 to} Ar ⁴ each independently represent an arylene group which may have a substituent, and X represents a single bond, an oxygen atom, a sulfur atom, or the following formula [2]. Or a group represented by the following formula [3], wherein R ¹ and R ² in the formula [2] each independently represent a hydrogen atom, an alkyl group, or an aryl group, and R ¹ and R 2 ² may be bonded to form a ring, and R ³ in the formula [3] is an alkylene group, an arylene group, or a group represented by the following formula [4], which is represented by the formula [4] R ⁴ and R ⁵ in the formula independently represent an alkylene group, Ar ⁵ represents an arylene group, k in formula [1] represents an integer of 0 to 5, provided that when K = 0. One of Ar ³ and Ar ⁴ is an arylene group having a substituent, and Y in Formula [1] is a single bond, oxygen atom A group represented by the following formula [5], wherein R ⁶ and R ⁷ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, or an aryl group. R ⁶ and R ⁷ may combine to form a ring.)

  An electrophotographic photosensitive member according to any one of claims 3 to 5, a charging unit for charging the electrophotographic photosensitive member, an exposure unit for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image, An electrophotographic cartridge comprising at least one of developing means for developing an electrostatic latent image formed on the electrophotographic photosensitive member and cleaning means for cleaning the electrophotographic photosensitive member.   An electrophotographic photosensitive member according to any one of claims 3 to 5, a charging unit for charging the electrophotographic photosensitive member, an exposure unit for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image, An image forming apparatus comprising: a developing unit that develops the electrostatic latent image formed on the electrophotographic photosensitive member.

Images