JP2009014940A - Electrophotographic photoreceptor, electrophotographic method, electrophotographic device, and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoreceptor having high durability, suppressing image degradation such as an afterimage due to increase in a residual potential or decrease in charging, and stably giving images with high picture quality. <P>SOLUTION: In the electrophotographic photoreceptor in which a protective layer containing fluorocarbon resin fine particles is formed on the outermost surface layer, the protective layer contains fluorocarbon resin fine particles by 20 to 60% in a volume fraction and a benzidine compound of a specified structure. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrophotographic photoreceptor having high durability and realizing high image quality. The present invention also relates to an electrophotographic method, an electrophotographic apparatus, and a process cartridge for an electrophotographic apparatus using the photoconductor.

  In recent years, there has been a remarkable development of image forming apparatuses using an electrophotographic system. In particular, laser printers and digital copying machines that convert information into digital signals and record information using light have significantly improved print quality and reliability. Furthermore, they have been applied to laser printers or digital copiers capable of full-color printing by fusing with high-speed technology. From such a background, it is particularly desirable to satisfy both high image quality and high durability as a required photoreceptor function.

  As photoconductors used in these electrophotographic laser printers, digital copiers, etc., those using organic photosensitive materials are widely applied for reasons such as cost, productivity and non-pollution. .

  However, the organic photoconductor (OPC) described above has a problem of abrasion resistance that the film is likely to be scraped by repeated use. When film scraping occurs, the photosensitive layer tends to be scraped, and the charged potential of the photosensitive member is degraded, the photosensitivity is deteriorated, the background is soiled due to scratches on the surface of the photosensitive member, the image density is lowered, or the image quality is deteriorated. strong. Furthermore, in recent years, there is a tendency that these are likely to occur due to the reduction in the diameter of the photosensitive member accompanying the increase in the speed of the electrophotographic apparatus or the downsizing of the apparatus.

On the other hand, in recent years, with a demand for higher image quality in the market, a small-diameter, spherical toner has attracted attention. However, such a small-diameter and spherical toner has a large rollability (propensity to roll easily) on the photosensitive member, and thus easily causes a cleaning failure, and image degradation due to toner filming or fusion is also an important issue. It has become.
In order to solve such a problem, for example, as disclosed in Patent Documents 1 and 2, etc., fluororesin fine particles are included as a lubricant in the surface layer of the photoconductor to reduce the photoconductor surface friction coefficient. The invention aiming at the surface releasing effect by is effective in the initial use. However, in the inventions described in these documents, it is necessary to set conditions such as a cleaning system and a toner, and as the life of the photosensitive member is extended, a change over time such as the disappearance of the surface release effect due to repeated use is accompanied. The effect was not sufficiently maintained.

Further, Patent Document 3 discloses that the surface layer of the photosensitive layer contains polytetrafluoroethylene powder as a lubricant and contains a charge transport material having a specific structural formula, thereby causing surface abrasion and scratches due to rubbing. It has been disclosed that it has durability against the occurrence of the above. Further, this publication can provide an electrophotographic photosensitive member having high durability capable of obtaining a high-quality image free from image blur, having good cleaning properties and no toner adhesion to the surface layer of the photosensitive member. It is disclosed that an electrophotographic photosensitive member having high durability can be provided.
However, as described in this publication, even if a large amount of fluororesin fine particles are added and the compound shown in this document is used, it can be said that a sufficient effect has not yet been obtained. Further, since the redox potential of the compound itself shown in this document is low, it is easy to form a charge trap due to alteration or the like, and therefore, there is a problem that the residual potential is likely to increase.
Further, an invention such as Patent Document 4 by the inventors of the present application is also known.
JP-A-5-45920 JP 2000-19918 A JP-A-8-160648 JP 2005-181396 A

  An object of the present invention is to provide a photoconductor that has high durability, suppresses image deterioration such as residual image due to increase in residual potential or decrease in charge, and can stably obtain a high-quality image even after repeated use over a long period of time. There is. In addition, by using such a photoconductor, it is not necessary to replace the photoconductor for a long period of time, and the device can be downsized with high-speed printing or a reduction in the diameter of the photoconductor. It is an object to provide an electrophotographic method, an electrophotographic apparatus, and an electrophotographic process cartridge capable of stably obtaining the above.

The above problems are solved by the following inventions 1) to 11).
1) In the electrophotographic photosensitive member in which a protective layer containing fluororesin fine particles is formed on the outermost surface layer, the protective layer is represented by the following general formula (A) and fluororesin fine particles having a volume fraction of 20 to 60%. An electrophotographic photosensitive member, comprising:

[In the general formula (A), R1 to R4 each independently represents a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group, which may be the same or different. May be. However, any one of R1-R4 is the following general formula (Y)

It is group shown by. n ₁ ~n ₄ each independently represents 0 or the integer 1. m _{1 to} m ₄ each independently represents an integer of 0 to 3 (however, in the case of 2 or 3, the groups 2 or 3 may be the same or different). However, m _{1 to} m ₄ are not 0 at the same time. Ar ^{1 to} Ar ¹⁰ represent a substituted or unsubstituted aromatic ring group, and may be the same or different. Ar ¹ and ˜Ar ¹⁰ adjacent to each other may form a ring together. a to b each independently represents an integer of 0 or 1 (in the general formula (Y), R5 and R6 may be the same or different, and each independently represents a substituted or unsubstituted alkyl group, substituted Or an unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted heterocyclic group bonded to each other at R5 and R6 and containing a nitrogen atom). ]

2) In an electrophotographic photoreceptor in which a protective layer containing fluororesin fine particles is formed on the outermost surface layer,
The electrophotographic photoreceptor, wherein the protective layer contains fluororesin fine particles having a volume fraction of 20% to 60% and a compound represented by the following general formula (B).

[In said general formula (B), R1-R4 represents a substituted or unsubstituted C1-C50 alkyl group or a substituted or unsubstituted aromatic hydrocarbon group, and may be same or different. However, any one of R1-R4 is the following general formula (Y)

It is group shown by. n _{1 to} n ₄ each independently represents an integer of 0 or 1. m _{1 to} m ₄ each independently represents an integer of 0 to 3 (however, in the case of 2 or 3, a plurality of the groups may be the same or different). However, m _{1 to} m ₄ are not 0 at the same time. Ar ^{1 to} Ar ¹⁰ represent a substituted or unsubstituted aromatic ring group, and may be the same or different. Ar ¹ and ˜Ar ¹⁰ adjacent to each other may form a ring together. a to b each independently represents an integer of 0 or 1 (in the general formula (Y), R5 and R6 may be the same or different, and each independently represents a substituted or unsubstituted alkyl group, substituted Or an unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted heterocyclic group bonded to each other at R5 and R6 and containing a nitrogen atom). ]

3) An electrophotographic method using the electrophotographic photosensitive member according to any one of 1) to 2), wherein at least charging, image exposure, development, and transfer are repeatedly performed on the electrophotographic photosensitive member.
4) The electrophotographic method is an electrophotographic method in which a process in which a cleaning process is further added to the process is repeated, and includes at least one of the charging process, the image exposure process, the developing process, the transfer process, and the cleaning process. The electrophotographic method according to 3), wherein a member is brought into contact with the photoconductor and the surface of the photoconductor is rubbed to attach the fluororesin particles to the surface.
5) The digital electrophotographic method described in 3) or 4) above, wherein an electrostatic latent image is formed on a photoreceptor by LD or LED during the image exposure.
6) The electrophotographic method according to any one of 3) to 5), wherein the toner used for image formation in the development is a substantially spherical toner.
7) An electrophotographic apparatus comprising at least a charging unit, an image exposing unit, a developing unit, a transferring unit, and the electrophotographic photosensitive member according to 1) or 2).
8) At least a charging unit, an image exposure unit, a development unit, a transfer unit, and the electrophotographic photosensitive member according to any one of the above 1) or 2), and a photoconductor by using an LD or an LED as the image exposure unit. A digital electrophotographic apparatus on which an electrostatic latent image is written.
9) The electrophotographic apparatus according to 7) or 8), wherein the electrophotographic apparatus is a tandem type having a plurality of sets of an electrophotographic photosensitive member, a charging unit and a developing unit, and a transfer unit.
10) a plurality of intermediate transfer means for primarily transferring the toner image developed on the electrophotographic photosensitive member onto the intermediate transfer member and then secondary transferring the toner image on the intermediate transfer member onto the recording material; 7) or 8), wherein a color image is formed by sequentially superimposing color toner images on the intermediate transfer member, and the color images are collectively transferred onto the recording material. Photo equipment.
11) A process cartridge for an electrophotographic apparatus, comprising: at least one of charging means, exposure means, developing means, cleaning means, and transfer means; and the electrophotographic photosensitive member according to 1) or 2).

  According to the present invention, there is provided a photoconductor that has high durability, suppresses image deterioration such as residual image due to increase in residual potential or decrease in charge, and can stably obtain a high-quality image even after repeated use over a long period of time. Can be provided. In addition, by using a stable photoconductor of these high-quality images, it is not necessary to replace the photoconductor, and it is possible to reduce the size of the apparatus in association with high-speed printing or a reduction in the diameter of the photoconductor. An electrophotographic method, an electrophotographic apparatus, and an electrophotographic process cartridge capable of stably obtaining an image can be provided.

The invention such as the photoreceptor of the present invention will be described in detail below with reference to embodiments.
In order to achieve high durability and low surface friction coefficient of an electrophotographic photosensitive member, it is known that it is effective to contain fluororesin fine particles in the outermost surface layer of the photosensitive member.
In the present invention, in order to maintain the sustainability of the low surface friction coefficient, fluororesin fine particles having a volume fraction of 20% or more are required for the outermost surface layer of the photoreceptor. However, if a layer having such a structure is formed, the interaction between the fluororesin fine particles described above becomes large, making it difficult to finely disperse the fluororesin fine particles in the dispersion liquid. Secondary aggregated particles (secondary particles: aggregates) increase.
Among these secondary particles, if huge secondary particles are present in the coating film, the surface of the coating film becomes uneven or easily peeled off, resulting in rough surfaces and poor cleaning and toner image disturbance. Cause it to cause. In addition, laser light, which is scanning light, is scattered on the aggregate, which causes disturbance of the exposure latent image or insufficient potential contrast, and causes an abnormal image.

  On the other hand, when the fluororesin fine particles are uniformly dispersed to the primary particles, the above-mentioned problems are solved, but the portion where the fluororesin fine particles are exposed on the coating film surface is reduced or reduced. As a result, the contact area between the toner and the fluororesin fine particles decreases, and the low friction effect due to the low surface coefficient of the photoreceptor becomes insufficient.

  As a result of intensive studies, the present inventors have considered that the fineness of the fluorine fine particles is localized in a certain range and covers the coating film surface with a certain area in consideration of the cleaning property of the toner. I found it necessary. That is, it has been found that a state in which the fluororesin fine particles cover the surface of the photoreceptor in an area ratio of 10 to 60% is most preferable. However, when the fluororesin fine particles are contained at such a high concentration, secondary particles are formed, and in a photoconductor having a structure containing secondary particles, the chargeability is lowered depending on the use conditions, and the memory effect (that is, afterimage) or the like. It may cause problems, and it may easily adsorb oxidizing gases such as ozone and NOx. In some cases, it may cause electrical resistance on the outermost surface and cause problems such as image flow. It turns out that there is.

Therefore, as a result of further investigation, when the surface layer contains at least one selected from the compounds represented by the general formulas (A) to (B) together with the above-described fluororesin fine particles, the memory effect and the oxidizing gas can be reduced. I found that the problem could be solved at once. The reason for this is not clarified at the present time, but the inclusion of the compounds of the general formulas (A) to (B) effectively suppresses the generation of radical substances that are likely to accumulate inside the heterogeneous particle structure. It is presumed that On the other hand, for the problem of oxidizing gas adsorption, the inclusion of the compounds of the above general formulas (A) to (B) suppresses the generation of radical substances in which the substituted amino group contained in the structure is effective. It is presumed that Moreover, since the said compound also has a charge transport capability, it is thought that the charge trap inside the secondary aggregation particle | grains by a fluororesin particle | grain is suppressed.
General formulas (A) to (B) preferably used together with the fluororesin fine particles in the present invention are:

  In the above formulas (A) to (B), R1 to R4 may be the same or different, and are substituted or unsubstituted alkyl groups, substituted or unsubstituted aromatic groups, or the following general formula (Y)

Represents. n _{1 to} n ₄ represent an integer of 0 or 1, m _{1 to} m ₄ represent an integer of 0 to 3 (provided that when m _{1 to} m ₄ is 2 or 3, the group present in 2 or 3 is They may be the same or different.) And a to b represent an integer of 0 or 1. However, m _{1 to} m ₄ are not 0 at the same time. Ar _{1 to} Ar ₁₀ represent a substituted or unsubstituted aromatic group and may be the same or different. Ar ₁ to Ar ₁₀ adjacent to each other may form a ring together. In the Y group, R5 and R6 each represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aromatic group, which may be the same or different, and R5 and R6 are bonded to each other and contain a nitrogen atom. A substituted or unsubstituted heterocyclic group may be formed.

More specifically, examples of the substituted or unsubstituted alkyl group having 1 to 50 carbon atoms represented by R1 to R4 include a methyl group, an ethyl group, a propyl group (i-propyl group, n-propyl group, etc.), a butyl group (i -Butyl group, t-butyl group, n-butyl group, etc.), pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group and undecyl group, etc. The alkyl group of 1-4) can be mentioned. These alkyl groups may be branched.
Examples of the substituted or unsubstituted aromatic groups include phenyl, benzyl, biphenyl, terphenyl, tetraphenyl, naphthalene, anthracene, and pyrene groups, and pyridine, quinoline, Examples thereof include monovalent to hexavalent aromatic heterocyclic groups composed of aromatic heterocyclic rings such as thiophene, furan, oxazole, oxadiazole, and carbazole.
When the substituted or unsubstituted alkyl group having 1 to 50 carbon atoms and the substituted or unsubstituted aromatic group represented by R1 to R4 have a substituent, the substituent may be an alkyl group (for example, having 1 carbon atom). In addition to-4), an alkoxy group, a halogen atom, an aromatic group, etc. are mentioned.

Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the aromatic group include the aromatic groups described above. (Preferably a monovalent aromatic group).
When R1 to R4 are groups represented by the above general formula (Y), a substituted or unsubstituted alkyl group and a substituted or unsubstituted aromatic group of R5 and R6 in the general formula (Y) Is the same as the case of the substituted or unsubstituted alkyl group and the substituted or unsubstituted aromatic group mentioned in the above-mentioned groups R1 to R4, and the substituent in the case of having a substituent is the same as above. Any one of R1 to R4 is a group represented by the general formula (Y).

Further, when two groups R5 to R6 are bonded to each other to form a heterocyclic group containing a nitrogen atom, specific examples thereof include a pyrrolidinyl group, a piperidinyl group, and a pyrrolinyl group. Examples of other heterocyclic groups containing a nitrogen atom include N-methylcarbazole, N-ethylcarbazole, N-phenylcarbazole, indole, quinoline and the like.
Also in the general formula (A) ~ (B), the n ₁ ~n ₄ each independently represents an integer of 0 or 1, the m ₁ ~m ₄ each independently represents an integer of 0 to 3. However, when m _{1 to} m ₄ are a plurality of 2 or 3, the 2 or 3 groups may be the same or different. M _{1 to} m ₄ are not 0 at the same time.

Also include substituted or unsubstituted aromatic groups described above as Ar ¹ to Ar ^10. However, the present invention is not limited to these compounds.
The amount of the compound represented by the general formula (A) or (B) is preferably 0.01 to 150% by weight with respect to the binder resin. If the amount is too small, the resistance to the oxidizing gas is insufficient. If the amount is too large, the film strength is lowered and the wear resistance is deteriorated.
Specific examples of the compound represented by the general formula (A) or (B) are shown below.

  Compound Nos. 1-1 to 1-12 in Tables 1 to 5 show examples of the compounds belonging to the general formula (A), and compounds Nos. 2-1 to 2-12 in Tables 6 to 10 are listed. Examples of the compound belonging to the general formula (B) are shown.

For example, in Compound _No. 1-1, which is a compound belonging to General Formula (A), a and b are 0 in General Formula (A), and Ar _{1 to} Ar ₄ and Ar _{7 to} Ar ₈ are phenylene groups (p - phenylene group), Ar ₅ ~Ar ₆ is a phenyl group, n ₁ ~n ₂ is 1, R1 to R2 is Y group, m ₁ ~m ₂ is 1, R5 and R6 Shows the case where is an ethyl group. Compound No. 1-2 is different from Compound No. 1-1 in that R5 and R6 are benzyl groups. In Compound No. 1-3, Ar _{7 to} Ar ₈ are a phenylene group (m-phenylene group). Compound No. 1-4 is different from Compound No. 1-1 in that R5 and R6 of Y group are bonded to each other to form a heterocyclic group containing a nitrogen atom (piperidinyl group). Compound No. 1-5 is different from Compound No. 1-1 in that R5 of the Y group is an ethyl group and R6 is a benzyl group. Compound No. 1-6 is different from Compound No. 1-1 in that m ₂ is 0 and R 5 and R 6 are benzyl groups. Compound No. 1-7 is a compound example in which a and b are 1, n _{3 to} n ₄ are 1, m _{3 to} m ₄ are 0, and R 3 and R 4 are phenyl groups. , Different from Compound No. 1-1 in that R5 and R6 of the Y group are benzyl groups. Compound No. 1-8 is a compound example showing a case where the aromatic group of Ar _{1 to} Ar ₂ has a substituent. In this compound, a is 1, b is 0, and R 1 to R 3 are Y groups. And R5 and R6 are propyl groups. Compound No. 1-9 is also an example of a compound in which a and b are 1 when the aromatic group of Ar ₁ to Ar ₂ has a substituent similarly to 1-8, and n _{1 to} n ₄ , Ar ₃ -Ar _{10 and} R1 to R4 are examples of the same, each being 1, a phenylene group (p-phenylene group) and the same Y group (R5 is a methyl group, R6 is a benzyl group). Compound No. 1-10 is an example of a compound in which a and b are 0 like Compound No. 1-1, and shows an example in which a plurality of substituents (here, 2) are present in the groups Ar _{5 to} Ar ₆ . This compound is also an example in which Ar _{7 to} Ar ₈ also have a substituent (n _{1 to} n ₂ are also 0). Compound No. 1-11 is a compound example in which a and b are 0, and n _{1 to} n ₂ are also 0, R 1 to R 2 are Y groups, R 5 is an ethyl group, and R 6 is a benzyl group. . Compound No. 1-12 is an example of a compound in which a and b are 0 and n _{1 to} n ₂ are also 0. This compound is an exemplary compound in the case where there are a plurality of Y groups (here 2), R5 and R6 are ethyl groups.

Compounds No.2-1~2-12 is a compound belonging to the general formula (B), R1-R6 in the general formula of the compound _{(B), a~b, n 1} ~n 4, m 1 ~m ₄ and Ar ^{1 to} Ar ¹⁰ are the same as those in the general formula (A) of the aforementioned compound Nos. 1-1 to 1-12 (that is, a in the general formula (A) of the compound No. 1-1 is compound No. 1-1). 2 corresponds to “a” in the general formula (B), and other combinations are also the same), and the description thereof is omitted.

<Layer structure of photoreceptor>
First, a layer configuration example of the electrophotographic photosensitive member of the present invention will be described with reference to the drawings.
In the electrophotographic photoreceptor of the present invention, the outermost surface layer (outermost layer) contains fluororesin particles in a specific amount, and at least one of the compounds represented by the general formula (A) or (B). Contains one.
In the example shown in FIG. 1, an example of a layer structure of a photoreceptor composed of a so-called single layer type photosensitive layer is shown. In the example shown in FIG. 1, the electrophotographic photoreceptor has a configuration in which a photosensitive layer 33 mainly composed of a charge generation material and a charge transport material and a protective layer 39 are laminated in this order on a conductive support 31. Here is an example. The protective layer 39 is a layer containing fluororesin fine particles.
The electrophotographic photosensitive member shown in FIG. 2 has a charge generation layer 35 mainly composed of a charge generation material, a charge transport layer 37 mainly composed of a charge transport material, and a protective layer 39 on a conductive support 31. The example which has the structure laminated | stacked in this order is shown. The protective layer 39 is a layer containing the same fluororesin fine particles as described above.
The electrophotographic photosensitive member shown in FIG. 3 has a charge transport layer 37 containing a charge transport material as a main component, a charge generation layer 35 containing a charge generation material as a main component, and a protective layer 39 on a conductive support 31. The example which has the structure laminated | stacked in this order is shown. Similarly to the above, the protective layer 39 is a layer containing fluororesin fine particles. The examples shown in FIGS. 2 and 3 are examples of the layer structure of an electrophotographic photosensitive member having a so-called laminated photosensitive layer.

<Conductive support>
As the conductive support 31 used in such a photoreceptor of the present invention, the following can be used which exhibits conductivity with a volume resistance of 10 ¹⁰ Ω · cm or less. For example, metal, such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, or metal oxide such as tin oxide or indium oxide, coated on film or cylindrical plastic or paper by vapor deposition or sputtering Is mentioned. Alternatively, a plate made of aluminum, aluminum alloy, nickel, stainless steel, or the like, and a tube subjected to surface treatment such as cutting, superfinishing, polishing, etc. after extruding them into a tube by a method such as drawing or the like are also included. These can be used as the conductive support 31. Further, an endless nickel belt or an endless stainless steel belt disclosed in Japanese Patent Application Laid-Open No. 52-36016 can also be used as the conductive support 31.
In addition to this, a conductive powder dispersed in an appropriate binder resin and coated on the support can also be used as the conductive support 31 in the present invention. Examples of the conductive powder include carbon black and acetylene black; metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver; metal oxide powder such as conductive tin oxide and ITO.
Furthermore, the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, tetrafluoroethylene resin (trade name: Teflon) on a suitable cylindrical substrate. What provided the electroconductive layer with the heat-shrinkable tube can also be used favorably as the electroconductive support body 31 in this invention.

<Binder resin used for conductive support>
The binder resin used for the conductive support is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. Polymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as resins, melamine resins, urethane resins, phenol resins, and alkyd resins. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.

Next, the photosensitive layer will be described. The photosensitive layer may be either a single layer type or a laminated type. For convenience of explanation, the photosensitive layer will be described first from the case of the laminated type composed of the charge generation layer 35 and the charge transport layer 37 (in the case of FIGS. 2 and 3).
<Laminated photosensitive layer>
The charge generation layer 35 is a layer mainly composed of a charge generation material. For the charge generation layer 35, a known charge generation material can be used. For example, a monoazo pigment, a disazo pigment, a trisazo pigment, a perylene pigment, a perinone pigment, a quinacridone pigment, a quinone condensed polycyclic compound, Examples thereof include squaric acid dyes, other phthalocyanine pigments, naphthalocyanine pigments, and azulenium salt dyes. These charge generation materials may be used alone or in combination of two or more.
For the charge generation layer 35, a liquid (coating liquid for charge generation layer) in which a charge generation material is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, an attritor, a sand mill, an ultrasonic wave, etc. It is formed by coating on a conductive support and drying.

  The binder resin used as necessary includes polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N-vinylcarbazole, poly Examples include acrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, and polyvinyl pyrrolidone. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generating material. The binder resin may be added before or after the charge generating material is dispersed.

Examples of the solvent include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin, etc. (Acetone, methyl ethyl ketone, cyclohexanone, etc.), ester solvents (ethyl acetate, methyl acetate), ether solvents (cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve) are preferably used. These may be used alone or in combination of two or more.
The charge generation layer coating liquid for forming the charge generation layer 35 is mainly composed of a charge generation material, a solvent, and a binder resin, and includes various kinds of agents such as a sensitizer, a dispersant, a surfactant, and silicone oil. Additives may be included.
Examples of the coating method of the coating liquid include dip coating, spray coating, beat coating, nozzle coating, spinner coating, ring coating, and the like.
The film thickness of the charge generation layer 35 formed using such a coating solution is preferably about 0.01 to 5 μm, and preferably 0.1 to 2 μm.

The charge transport layer 37 can be formed by applying and drying a dispersion liquid (coating liquid for charge transport layer) in which a charge transport material and a binder resin are dissolved or dispersed in an appropriate solvent and drying the charge transport layer. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed. These can be used alone or in combination of two or more.
The charge transport material used for such a charge transport layer includes an electron transport material and a hole transport material.

  Examples of the electron transport material include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives.

Examples of hole transport materials include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives, etc. Known materials may be mentioned.
These charge transport materials can be used alone or in admixture of two or more.

Examples of the binder resin include the thermoplastic or thermosetting resin used in the above-described conductive support.
The amount of the charge transport material is 20 to 300 parts by weight, preferably 40 to 150 parts by weight, with respect to 100 parts by weight of the binder resin. The thickness of the charge transport layer is preferably 25 μm or less from the viewpoint of resolution and responsiveness. On the other hand, the lower limit is preferably 5 μm or more, although it varies depending on the system to be used (particularly charging potential).
As the solvent, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used. These may be used singly or in combination of two or more.

  For the charge transport layer, a polymer charge transport material having both functions as a charge transport material and a binder resin is also preferably used. A charge transport layer composed of these polymer charge transport materials is excellent in wear resistance. As such a polymer charge transport material, known materials can be used, and in particular, a polycarbonate containing a triarylamine structure in at least one of a main chain or a side chain is preferably used. Among these, polymer charge transport materials represented by the following general formulas (I) to (X) are preferable.

[In the above formula (I), R _{1 to} R ₃ each independently represents an alkyl group or a halogen atom which may have a substituent, and R ₄ represents an alkyl which may have a hydrogen atom or a substituent. Group, R _{5 to} R ₆ are aryl groups which may have a substituent, o, p and q each independently represent an integer of 0 to 4, and when o to q is 2 or more, each R ₁ to R ₃ may be the same or different. k and j represent composition ratios, and are 0.1 ≦ k ≦ 1 and 0 ≦ j ≦ 0.9, respectively, and n represents the number of repeating units within a range of 5 to 5000. X represents an aliphatic divalent group, a cycloaliphatic divalent group, or a divalent group represented by the following general formulas (I-1) and (I-2). ]

[In the formula (I-1), R ₁₀₁ and R ₁₀₂ each independently represents an alkyl group which may have a substituent, an aryl group which may have a substituent, or a halogen atom. l and m are integers of 0 to 4, and when l and m are 2 or more, each R _{101 to} R ₁₀₂ may be the same or different, Y is a single bond, a straight chain having 1 to 12 carbon atoms , Branched or cyclic alkylene group, —O—, —S—, —SO—, —SO ₂ —, —CO— or —CO—O—Z—O—CO— (Z is an aliphatic divalent group) ). ]

(Wherein, a represents an integer of 1 to 20, b represents an integer of 1 - 2000, R _103, R ₁₀₄ are each independently have a optionally substituted alkyl group or a substituted group And R ₁₀₃ and R ₁₀₄ present in a plurality of side chains of Si may be the same or different from each other.

[In formula, R < ₇ > -R < ₈ > is the aryl group which may have a substituent, Ar < ₁ > -Ar < ₃ > may be same or different and represents the arylene group which may have a substituent. X, k, j and n have the same meaning as in the general formula (I). ]

[In formula, R < ₉ > -R < ₁₀ > represents the aryl group which may have a substituent, Ar < ₄ > -Ar < ₆ > respectively independently represents the arylene group which may have the same or different substituent. X, k, j and n have the same meaning as in the general formula (I). ]

[In formula, R < ₁₁ > -R < ₁₂ > represents the aryl group which may have a substituent, Ar < ₇ > -Ar < ₉ > respectively independently represents the same or different arylene group which may have a substituent. X, k, j and n have the same meaning as in the general formula (I). ]

[In formula, R < ₁₃ > -R < ₁₄ > is the aryl group which may have a substituent, Ar < ₁₀ > -Ar < ₁₂ > is the same or different arylene group which may have a substituent, X < ₁ > -X < ₂ > Represents an ethylene group which may have a substituent or a vinylene group which may have a substituent. X, k, j and n have the same meaning as in the general formula (I). ]

[Wherein, R _{15 to} R ₁₈ are each independently an aryl group that may have a substituent, Ar _{13 to} Ar ₁₆ are each independently an arylene group that may have a substituent, Y ₁ to Y ₃ each independently represent a single bond, an optionally substituted alkylene group, an optionally substituted cycloalkylene group, an optionally substituted alkylene ether group, oxygen atom, Represents a sulfur atom or vinylene group. X, k, j and n have the same meaning as in the general formula (I). ]

[Wherein, R _{19 to} R ₂₀ each independently represents a hydrogen atom or an aryl group which may have a substituent, and R ₁₉ and R ₂₀ may be bonded to each other to form a ring. . Ar _{17 to} Ar ₁₉ each independently represent the same or different arylene group which may have a substituent. X, k, j and n have the same meaning as in the general formula (I). ]

[Wherein, R ₂₁ represents an aryl group which may have a substituent, and Ar _{20 to} Ar ₂₃ each independently represent the same or different arylene group which may have a substituent. X, k, j and n have the same meaning as in the general formula (I). ]

Wherein, R ₂₂ to R ₂₅ are each independently an optionally substituted aryl group, Ar ₂₄ to Ar ₂₈ are each independently, the same may have a substituent or an arylene group Represents. X, k, j and n have the same meaning as in the general formula (I). ]

[Wherein R _{26 to} R ₂₇ each independently represents a substituted or unsubstituted aryl group, and Ar _{29 to} Ar ₃₁ each independently represent the same or different arylene group which may have a substituent. To express. X, k, j and n have the same meaning as in the general formula (I). ]
As a coating method of the coating solution, a conventional coating method such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, ring coating, or the like can be used.

Next, the case where the photosensitive layer is a single layer type (in the case of FIG. 1) will be described.
<Single layer type photosensitive layer>
In the case where the photosensitive layer is of a single layer type, a photosensitive layer 33 having a charge generating substance, a charge transporting substance and a binder resin can be used. Such a photosensitive layer 33 can be formed by applying and drying a coating solution in which a charge generating material, a charge transporting material, and a binder resin are dissolved or dispersed in an appropriate solvent. In addition, necessary plasticizers, leveling agents, antioxidants, and the like can be added to the coating liquid.
As the binder resin, in addition to the binder resin previously mentioned in the charge transport layer 37, the binder resin mentioned in the charge generation layer 35 may be mixed and used. Of course, the polymer charge transport materials listed above can also be used favorably. The amount of the charge generating material with respect to 100 parts by weight of the binder resin is preferably 5 to 40 parts by weight, and the amount of the charge transport material is preferably more than 0 and not more than 190 parts by weight, more preferably 50 to 150 parts by weight. The photosensitive layer is formed by dip coating, spray coating, bead coating, a coating solution in which a charge generating material and a binder resin are dispersed together with a charge transport material using a solvent such as tetrahydrofuran, dioxane, dichloroethane, and cyclohexane. It can be formed by coating with a ring coat or the like. The film thickness of the photosensitive layer is suitably about 5 to 25 μm.

<Protective layer>
In the photoreceptor of the present invention, a protective layer 39 is provided on the photosensitive layer for the purpose of protecting the photosensitive layer and maintaining a low surface friction coefficient. Examples of the binder resin used for the protective layer 39 include ABS (acryl-butadiene-styrene) resin, ACS (acryl-chlorinated polyethylene-styrene) resin, olefin-vinyl monomer copolymer, chlorinated polyether, and aryl resin. , Phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone Polystyrene, polyarylate, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinylidene chloride, epoxy resin, etc. I can get lost. From the viewpoint of dispersibility of fluororesin fine particles, residual potential, and coating film defects, polycarbonate or polyarylate is particularly effective and useful.

Examples of fluororesin fine particles that can be used for the outermost surface layer of the photoreceptor of the present invention include, for example, tetrafluoroethylene resin fine particles, perfluoroalkoxy resin fine particles, trifluorochloroethylene resin fine particles, hexafluoroethylene propylene resin fine particles, Examples thereof include vinyl fluoride resin fine particles, vinylidene fluoride resin fine particles, ethylene fluoride dichloride resin fine particles and copolymers thereof, and one or more of these are appropriately selected. Ethylene fluoride resin fine particles and perfluoroalkoxy resin fine particles are preferred. The particle size can be 0.1 to 10 μm, preferably 0.15 to 2.0 μm, and the particle size can be adjusted by a dispersion treatment described later as required.
The fluororesin fine particles having a secondary particle diameter of 0.3 to 4 μm must cover the surface of the photoreceptor by 10 to 60% by area ratio, preferably the secondary particle diameter is 0.3 to 1.5 μm. is there. If the coverage is less than 10%, the low surface friction coefficient when viewed microscopically becomes insufficient, and if the coverage exceeds 60%, the transmittance of the laser beam is remarkably reduced, making it difficult to form an electrostatic latent image. Become. On the other hand, if the size of the secondary particles exceeds 4 μm, the above-mentioned toner contact surface shortage may occur or abnormal images may be caused by laser light scattering.

  Furthermore, in order to maintain a low surface friction coefficient even in repeated use, it is preferable to contain 20 to 60% of fluororesin fine particles in volume fraction. More preferably, it is 30 to 50%. As a result, even on photoreceptors where the amount of wear is significantly reduced due to the low μ (μ: surface friction coefficient), the necessary and sufficient amount of fluororesin fine particles continues to be extended, resulting in a low surface friction coefficient and high durability. Is done. If the volume fraction is less than 20%, even if the above-mentioned coverage can be ensured in the vicinity of the surface, the low surface friction coefficient will not be exhibited when the inside of the protective layer is exposed to the surface due to wear. On the other hand, when the volume fraction exceeds 60%, the amount of the binder resin is decreased, so that the mechanical strength of the coating film is remarkably lowered and the life of the photoreceptor is reduced.

Further, the outermost layer contains fluororesin fine particles, and the fluororesin fine particles are projected on the surface of the secondary particles formed by agglomerating a plurality of primary particles and primary particles in the outermost layer film. When the total of the projected area ratio (covered area ratio) on the surface of the particles whose average diameter is in the above-mentioned range is 10% or more, the coefficient of friction of the photoreceptor surface is very small, and the low coefficient of friction is Since it is maintained even after repeated use, good cleaning properties are maintained over a long period of time, wear is very small, and the durability of the photoreceptor is increased.
Here, the average diameter of the projected image is a particle or an aggregate of particles seen when the surface of the outermost layer is observed from a substantially vertical direction as one particle, and the inner diameter passing through the center of gravity is 2 degrees in the projected image. Average value measured in steps.

In the photoreceptor of the present invention, observation with a scanning electron microscope (SEM) will be described as a method for calculating the average diameter and area ratio of the projected image of the portion where the fluororesin fine particles are exposed on the surface. However, the method is not limited to the method described below, as long as the exposed state of the fluororesin fine particles can be observed or evaluated.
The surface of the electrophotographic photosensitive member in which the fluororesin fine particles are dispersed is photographed by SEM, and the fluororesin fine particle image displayed on the obtained SEM image is analyzed using an image analyzer, and the average diameter of the fine particles, The number, area ratio, etc. can be obtained. At this time, since the image obtained as the SEM image is projected (captured) from a substantially vertical direction on the surface, the image of the fluororesin fine particles displayed is also a projected image in the vertical direction. Here, the average diameter of the projected image is an average value obtained by measuring the inner diameter passing through the center of gravity in increments of 2 degrees with respect to a projected image in which particles or aggregates of particles seen when observed are regarded as one particle.

  The image analysis device is capable of binaryly distinguishing the projection image of the fluororesin fine particles from the binder resin around the image, and a condition in which secondary particles in which a plurality of primary particles are aggregated can be approximated as large particles. It is necessary to be able to select. Furthermore, it is necessary to have a program capable of calculating at least the average diameter and the area ratio for each projected image of such fluororesin fine particles. As such an image analysis apparatus, a dedicated apparatus such as a high-detail image analysis system IP-1000 (manufactured by Asahi Engineering Co., Ltd.), a computer in which image analysis software Image-Pro Plus (manufactured by Planetron Co., Ltd.) is installed, or the like is used. Can do.

  When the acceleration voltage is high, an SEM image may be obtained as image information not only near the surface but also inside the surface. In a system in which fluorine fine particles are dispersed in a binder resin, when the acceleration voltage is high, there may be a case where the fluororesin fine particles inherent in the vicinity of the surface not exposed to the surface are transmitted and observed. For this reason, the acceleration voltage to be observed needs to be adjusted so that the fluororesin fine particles exposed on the surface are projected.

For example, when a field emission scanning electron microscope S-4200 (manufactured by Hitachi, Ltd.) is used as the SEM, the acceleration voltage is preferably about 2 kv to 6 kv, which depends on the device and the material of the photoconductor. It is necessary to adjust accordingly.
The surface SEM image obtained in this way is taken into image analysis software, and the average diameter and area ratio of the individual fluororesin fine particles counted in the observation range are calculated, and the state of the desired fluororesin fine particles on the surface of the photoreceptor is determined. It can be observed.

  Further, it is preferable to further add a fluorosurfactant as a dispersant for promoting the dispersion of the fluororesin fine particles. Examples of such a surfactant include a surfactant such as a block copolymer of a segment compatible with a binder resin and a fluorine segment (for example, product name Modiper F manufactured by NOF Corporation). By adding the surfactant, reaggregation of the fluororesin fine particles can be suppressed, and a finer photosensitive layer forming coating solution can be obtained. In the photosensitive layer thus obtained, the affinity between the fluororesin and the binder resin is increased, and the detachment of the fluororesin from the binder resin is prevented. It is considered that an effect of improving wearability can also be obtained.

  Moreover, you may add a filler in order to improve abrasion resistance to a protective layer. As the filler, there are an organic filler and an inorganic filler. From the viewpoint of the hardness of the filler, the use of the inorganic filler is advantageous for improving the wear resistance. Such inorganic filler materials include metal powders such as copper, tin, aluminum, and indium; silica, tin oxide, zinc oxide, titanium oxide, alumina, zirconium oxide, indium oxide, antimony oxide, bismuth oxide, and calcium oxide. Metal oxides such as tin oxide doped with antimony and indium oxide doped with tin; metal fluorides such as tin fluoride, calcium fluoride and aluminum fluoride; inorganic such as potassium titanate and boron nitride Materials.

  When the dispersibility of the filler is lowered, the residual potential increases, the transparency of the coating film decreases, the occurrence of coating film defects, and further the wear resistance decreases. It is preferable from the viewpoint of the dispersibility of the filler to use a filler surface-treated with.

As such a surface treatment agent, a conventionally used surface treatment agent can be used, but it is preferable to use a surface treatment agent that can maintain the insulating properties of the filler. For example, titanate coupling agents, aluminum coupling agents, zircoaluminate coupling agents, higher fatty acids, etc., or combined treatment with these and silane coupling agents, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Silicone, aluminum stearate, or the like, or a mixture thereof is more preferable from the viewpoint of filler dispersibility and image blur. The treatment with the silane coupling agent is strongly influenced by image blur, but the influence may be suppressed by performing a mixing treatment of the surface treatment agent and the silane coupling agent. The amount of the surface treatment agent varies depending on the average primary particle size of the filler used, but is preferably 3 to 30% by weight, more preferably 5 to 20% by weight. When the amount of the surface treatment agent is less than 3% by weight, the filler dispersing effect cannot be obtained, and when it is more than 30% by weight, the residual potential is significantly increased.

As the solvent, all solvents used in the charge transport layer 37 such as tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone, and the like can be used. However, a solvent having a high viscosity is preferable at the time of dispersion, but a solvent having high volatility is preferable at the time of coating. When there is no solvent satisfying these conditions, it is possible to use a mixture of two or more solvents having respective physical properties, which may have a great effect on the dispersibility of the fluororesin fine particles.
Further, the addition of the low molecular charge transport material or the polymer charge transport material mentioned in the charge transport layer 37 to the protective layer is effective and useful for reducing the residual potential and improving the image quality.

  The fluororesin fine particles can be dispersed together with at least an organic solvent using a conventional method such as an attritor, a sand mill, a vibration mill, or an ultrasonic wave. In particular, it is more preferable from the viewpoint of dispersibility to employ a dispersion method using a ball mill or a vibration mill in which impurities from the outside are few. As the dispersion medium (dispersion medium), various media such as zirconia, alumina, and agate that have been used in the past can be used. From the viewpoint of the effect on the dispersibility of the fluororesin fine particles, the dispersion medium is particularly zirconia. Is preferred. In some cases, dispersibility may be further increased by combining these dispersion methods. Further, a dispersant may be added to the resin for the purpose of controlling the dispersibility of the fluororesin fine particles. As such a dispersant, a fluorine-based surfactant, a graft polymer, a block polymer, a coupling agent, and the like can be used.

  As a method for forming the protective layer, conventional methods such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, ring coating, etc. can be used. preferable. Furthermore, it is possible to form the protective layer by coating the required film thickness of the protective layer at one time, but it is better to adopt a method of recoating (multiple coating method) to apply two or more times, It is more preferable to make the protective layer into a multilayer by such an overcoating method in terms of uniformity of the fluororesin fine particles in the film. The thickness of the protective layer can be set freely, but when the protective layer thickness is significantly increased, the image quality tends to be slightly deteriorated. About 10 μm is appropriate.

<Other layers>
In the photoreceptor of the present invention, an undercoat layer can be provided between the conductive support 31 and the photosensitive layer. The undercoat layer is mainly composed of a resin. As a resin that can be used for this layer, a resin having a high solvent resistance with respect to a general organic solvent is desirable in consideration of applying a photosensitive layer thereon with a solvent. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, fine powder pigments of metal oxides such as titanium oxide, silica, alumina, zirconium oxide, tin oxide and indium oxide may be added to the undercoat layer in order to prevent moire and reduce residual potential.
These undercoat layers can be formed using an appropriate solvent and a coating method like the above-mentioned photosensitive layer. The undercoat layer of the present invention, a silane coupling agent, titanium coupling agent, zirconium coupling agent, can also be used chrome coupling agent, which the Al ₂ O ₃ is provided by anodic oxidation, poly para-xylylene (parylene), or the like of the organic substances and _{SiO 2, SnO 2, TiO 2} , ITO, may be preferably used an inorganic material such as CeO ₂ which is provided by a vacuum thin-film forming method. Furthermore, what is used for a well-known undercoat layer can also be mentioned. The thickness of the undercoat layer is suitably from 0 to 5 μm.

  In the photoreceptor of the present invention, an intermediate layer can be provided between the photosensitive layer and the protective layer. The intermediate layer uses a binder resin as a main component. Examples of these resins include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. Examples of the method for forming the intermediate layer include the coating methods described above. When providing an intermediate layer, the thickness of the intermediate layer is suitably about 0.05 to 2 μm.

<Electrophotographic method and electrophotographic apparatus>
Next, an electrophotographic method and an electrophotographic apparatus of the present invention will be described with reference to the drawings.
FIG. 4 is a schematic view for explaining the electrophotographic process and the electrophotographic apparatus of the present invention.
In FIG. 4, the photosensitive member 1 is provided with at least a photosensitive layer, and has the outermost surface layer used in the photosensitive member of the present invention as the outermost surface layer. The photosensitive member 1 has a drum shape, but may be a sheet shape or an endless belt shape. For the charging charger 3, the pre-transfer charger 7, the transfer charger 10, the separation charger 11, and the pre-cleaning charger 13, known charging means such as corotron, scorotron, solid state charger (solid state charger), charging roller or the like can be used. Thus, a charging step or the like is performed using these charging means.
As the transfer means, the above-described charger can be used, but a combination of the transfer charger and the separation charger shown in the figure is effective.
The light source such as the image exposure unit 5 and the charge removal lamp 2 emits light such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL). All things can be used. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.
In FIG. 4, a latent image forming process is performed in which an electrostatic latent image is formed on the photoreceptor by the image exposure unit 5 (having an LD or LED) on the uniformly charged photoreceptor 1 surface.
In addition to the steps shown in FIG. 4, the photosensitive member is irradiated with light by a transfer step using light irradiation, a static elimination step, a cleaning step, or a pre-exposure step.

The developing toner on the photosensitive member 1 is transferred to the transfer paper 9 by the developing unit 6. However, not all of the toner is transferred, and some toner remains on the photoreceptor 1. Such toner is removed from the photoreceptor by the fur brush 14 and the cleaning brush 15. Cleaning may be performed only with a cleaning brush, and a known brush such as a fur brush or a mag fur brush is used as the cleaning brush.
Image exposure is performed after the electrophotographic photosensitive member is uniformly positively (or negatively) charged to form a positive (negative) electrostatic latent image on the surface of the photosensitive member. If this is developed with negative (or positive) polarity (reverse polarity) toner (detection fine particles), a positive image can be obtained, and if developed with positive (negative) toner, a negative image can be obtained.
As the developing means used for this development, a known developing means is applied, and a known static eliminating means is also used as the static eliminating means.

In the electrophotographic method of the present invention, the shape of the toner used for image formation is not limited, but a spherical shape having a particularly high circularity is preferable.
Such a spherical toner has an average circularity of 0.930 to 0.995, and the toner has a specific shape.
As the spherical toner having a circularity of 0.930 to 0.995, a polymerized toner produced by a conventionally known polymerization method can be used. Further, in the present invention, a polymerization method may be used as a spherical toner having a small particle size with high resolution and good transferability, but the present invention is not limited to this, and for example, conventional mechanical grinding A toner prepared by a classification method may be used, or a toner that has been subjected to thermal or mechanical post-treatment to be rounded may be used. Further, in the present invention, the toner may be a two-component developing toner or a magnetic toner.
As a method for measuring the toner shape (circularity), an optical detection zone method is used in which a suspension containing particles is passed through an imaging zone detection zone on a flat plate, and a particle image is optically detected and analyzed by a CCD camera. Is appropriate.
In this method, the projected area of the particle can be obtained. The circularity is a value obtained by dividing the circumference of an equivalent circle having the same area as the projected area by the circumference of the actual particle. This value is a value measured as an average circularity by a flow type particle image analyzer FPIA-2000 (manufactured by Sysmex Corporation).
As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance. About 0.1 to 0.5 g. The suspension in which the sample is dispersed is subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the concentration of the dispersion is set to 3000 to 10,000 / μl, and the shape of the toner and the shape distribution of the toner are measured by the apparatus. Can do.

  The image forming apparatus of the present invention can include an abutting member that contacts and rubs against the electrophotographic photosensitive member. An example of such a contact member is a contact member for the purpose of rubbing the exposed portion of the fluororesin fine particles. Also, a pressure mechanism used to press a member used in a general image forming apparatus such as a contact charging member such as a charging roller, a cleaning member such as a cleaning blade or a cleaning brush, a transfer member such as a transfer belt or an intermediate transfer belt, etc. Can also be provided as a contact member. Here, a case where the contact member is rubbed against the surface of the photoreceptor with the cleaning brush 15 will be described as an example. The cleaning blade is preferable because it has a great effect of rubbing the entire surface of the photoconductor while pressing the surface of the photoconductor with a substantially uniform pressure to uniformly attach the fluororesin fine particles to the surface. Using such a contact member, the charging, image exposure, development, transfer, and cleaning steps are repeated as described above, and at least one of the charging, image exposure, development, transfer, and cleaning steps is performed. Further, the fluororesin particles can be evenly or substantially uniformly adhered to the surface of the photoreceptor of the present invention by making contact with the photoreceptor for the purpose of rubbing and rubbing almost the entire surface of the photoreceptor as described above. .

When coating a fluororesin with a cleaning blade, the various conditions of the cleaning blade include a blade contact angle of 10 to 30 degrees, a contact pressure of 0.3 to 4 g / mm, and a rubber hardness of the urethane rubber used as the blade (JIS-A Hardness) 60-70 degrees, rebound resilience (according to JIS K-6301) 30-70%, Young's modulus 30-60 kgf / cm ² , thickness 1.5-3.0 mm, free length 7-12 mm and blade edge The amount of biting into the photosensitive member is preferably in the range of 0.2 to 2 mm.

FIG. 5 shows another example of the electrophotographic process and apparatus of the present invention. As the photoreceptor 21, the above-described photoreceptor of the present invention having at least a photosensitive layer is used. This photoreceptor employs the outermost surface layer having the above-mentioned specific volume fraction of fluororesin particles and a specific compound. Such an electrophotographic method and apparatus of the present invention are driven by the driving rollers 22a and 22b, charged by the charger 23 (charging process), image exposure (latent image forming process) by the light source 24, and development (developing process: FIG. (Not shown), transfer using the transfer charger 25 (transfer process), exposure before cleaning by the light source 26, cleaning by the cleaning brush 27 (cleaning process), and static elimination (initialization process) by the light source 28 are repeated. In FIG. 5, the photoconductor 21 (in the case shown in FIG. 5, the support is translucent) is irradiated with light for pre-cleaning exposure from the support side by a pre-cleaning exposure light source.
The illustrated electrophotographic process is an example of the electrophotographic process and apparatus of the present invention, and needless to say, other forms are possible. For example, FIG. 5 shows an example in which exposure before cleaning is performed from the support side, but this may be performed from the photosensitive layer side. In addition, image exposure and neutralizing light irradiation may be performed from the support side.
In FIG. 5, light irradiation shows each process by each exposure means of image exposure, exposure before cleaning, and static elimination exposure. In addition, a pre-transfer exposure, an image exposure pre-exposure, and other known light irradiation means may be provided, and each light irradiation step may be performed on the photoreceptor using these exposure means.
The image forming means as described above may be fixedly incorporated in an apparatus such as a copying apparatus, a facsimile machine, or a printer, or may be incorporated in such a copying apparatus in the form of a process cartridge. Such a process cartridge of the present invention only needs to contain at least the photoreceptor of the present invention, and in addition, a single apparatus (including a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit) Parts). The shape and the like of the process cartridge are various and not limited at all. An example thereof is shown in FIG. The photoreceptor 16 is the photoreceptor of the present invention, and the photoreceptor 16 has at least a photosensitive layer on a conductive support, and has a specific filler on the outermost surface layer and the general formula (A) or It contains a compound represented by at least one of (B).

Next, as a full-color image forming apparatus to which the present invention is applied, an electrophotographic printer (hereinafter simply referred to as a printer) will be described as an example.
FIG. 7 is a schematic configuration diagram of the printer according to the present embodiment. In FIG. 7, the surface of a photoreceptor 56 as a latent image carrier is uniformly charged by a charging charger 53 using a corotron or a scorotron while being rotated counterclockwise in the figure (charging process). The electrostatic latent image is carried by scanning with laser light L emitted from a laser optical device (not shown) (image exposure process (latent image forming process)). Since this scanning is performed based on image information obtained by decomposing a full-color image into yellow, magenta, cyan, and black color information, an electrostatic latent image for yellow, magenta, cyan, or black is formed on the photosensitive drum 56. The A revolver developing unit 50 is disposed on the left side of the photosensitive drum 56 in the drawing. This has a yellow developing unit, a magenta developing unit, a cyan developing unit, and a black developing unit in a rotating drum-shaped casing, and each developing unit is sequentially moved to a developing position facing the photosensitive drum 56 by rotation. Move. The yellow developer, magenta developer, cyan developer, and black developer are for developing an electrostatic latent image by attaching yellow toner, magenta toner, cyan toner, and black toner, respectively. An electrostatic latent image for yellow, magenta, cyan, and black is sequentially formed on the photosensitive drum 56, and these images are sequentially developed by the developing units of the revolver developing unit 50, so that a yellow toner image, a magenta toner image, and a cyan toner are developed. It becomes a toner image and a black toner image (development process).

  An intermediate transfer unit is disposed on the downstream side of the photosensitive drum 56 from the development position. This is because the intermediate transfer belt 58 stretched by the tension roller 59a, the intermediate transfer bias roller 57 as the transfer means, the secondary transfer backup roller 59b, and the belt drive roller 59c is driven by the rotation of the belt drive roller 59c. Move endlessly clockwise. The yellow toner image, magenta toner image, cyan toner image, and black toner image developed on the photosensitive drum 56 enter an intermediate transfer nip where the photosensitive drum 56 and the intermediate transfer belt 58 are in contact with each other. Then, while being influenced by the bias from the intermediate transfer bias roller 57, the toner image is superposed on the intermediate transfer belt 58 and intermediately transferred to form a superposed toner image in which all four color toner images are superimposed (transfer process).

The drum cleaning unit 55 cleans the transfer residual toner on the surface of the photosensitive drum 56 that has passed through the intermediate transfer nip with rotation (cleaning step). The drum cleaning unit 55 cleans the transfer residual toner by a cleaning roller to which a cleaning bias is applied. The drum cleaning unit 55 may use a cleaning brush such as a fur brush or a mag fur brush, or a cleaning blade.
The surface of the photosensitive drum 56 from which the transfer residual toner has been cleaned is discharged by the discharging lamp 54. As the static elimination lamp 54, the above-described light source such as a fluorescent lamp can be used. An LED or a semiconductor laser LD is used as a light source of the laser optical device. For these emitted light, various filters such as the above-described sharp cut filter may be used so that only a desired wavelength region is used.

  On the other hand, the registration roller pair 61 that sandwiches the transfer paper 60 fed from a paper feed cassette (not shown) between the two rollers overlaps the superposed toner image on the intermediate transfer belt 58 at the timing of the secondary transfer. The transfer paper 60 is fed toward the nip. The superposed toner image on the intermediate transfer belt 58 is secondarily transferred onto the transfer paper 60 collectively under the influence of the secondary transfer bias from the paper transfer bias roller 63 in the secondary transfer nip. By this secondary transfer, a full color image is formed on the transfer paper 60 (transfer process). The transfer paper 60 on which the full-color image is formed is sent to the transport belt 64 by the transfer belt 62, and the transfer paper 60 is sent to the fixing unit 65 by the transport belt 64. The fixing unit 65 conveys the transferred transfer paper 60 by being sandwiched between fixing nips formed by the contact between the heating roller and the backup roller. The full color image on the transfer paper 60 is fixed on the transfer paper 60 by heating from a heating roller and pressurization by a fixing nip (fixing step). A bias for adsorbing the transfer paper 60 is applied to the transfer belt 62 and the conveyance belt 64, and a paper static elimination charger that neutralizes the transfer paper 60 and each belt (intermediate transfer belt 58, transfer belt 62, conveyance). The figure is omitted in that three belt charge-removing chargers for removing the charge from the belt 64) are provided. Further, the intermediate transfer unit is also provided with a belt cleaning unit having the same configuration as the drum cleaning unit 55. The residual toner on the intermediate transfer belt 58 is cleaned by the belt cleaning unit.

FIG. 8 shows a modified example (another example) of the image forming apparatus according to the present embodiment. This image forming apparatus is a tandem type image forming apparatus having an intermediate transfer belt 87, and the photosensitive drums 80Y, 80M, 80C, and 80Bk for each color are separately used instead of sharing the photosensitive drum 80 for each color. I have. Also, a drum cleaning unit 85, a charge removal lamp 83, and a charging roller 84 for uniformly charging the drum are provided for each color. In the printer shown in FIG. 7, the charging charger 53 is provided as the drum uniform charging means, but in this apparatus, the charging roller 84 is provided.
In the tandem method as shown in FIG. 8, latent image formation and development of each color can be performed in parallel, so that the image forming speed can be much faster than the revolver method as shown in FIG. . Even in the tandem system, the surface of the photoconductor 80 initialized by the static elimination lamp is uniformly charged by the charging roller 84 (charging process), and is scanned optically by the exposure light source (including LED or LD) 81 to be latent. An image is formed (image exposure process (latent image forming process)), and developed by the developing unit 82 (development process). The toner images of each color are transferred to the intermediate transfer belt 87, and the toner images of each color are combined to form an image carrier. Then, the image is transferred to the paper 89 (transfer process) and heated and pressed by the fixing unit 93 to fix the image on the paper (fixing process).

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not restrict | limited by these Examples. “Parts” are all parts by weight.

[Example 1]
An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition on an aluminum cylinder are sequentially applied by dip coating and then dried to form an undercoat layer having a thickness of 3.5 μm. A charge generation layer having a thickness of 0.2 μm and a charge transport layer having a thickness of 22 μm were formed.
Undercoat layer coating solution / titanium dioxide powder: 400 parts / melamine resin: 65 parts / alkyd resin: 120 parts / 2-butanone: 400 parts
Charge generation layer coating solution -Bisazo pigment of the following [Chemical Formula 19]: 12 parts-Polyvinyl butyral: 5 parts-2-butanone: 200 parts-Cyclohexanone: 400 parts

Charge transport layer coating solution-Polycarbonate (Z Polyca, manufactured by Teijin Chemicals): 8 parts-Charge transport material of the following [Chemical formula 20]: 10 parts-Tetrahydrofuran: 100 parts

Furthermore, on the charge transport layer, a protective layer coating solution having the following composition was circulated for 30 minutes under a pressure of 100 MPa using a high-speed liquid collision dispersion device (device name: Optimizer HJP-25005, manufactured by Sugino Machine Co., Ltd.) Then, it was prepared by irradiation with ultrasonic waves for 10 minutes, spray coating [spray gun: Peacecon PC308, manufactured by Olympos, air pressure: 2 kgf / cm ² ], dried at 130 ° C. for 60 minutes, and a protective layer of about 5 μm. The electrophotographic photoreceptor 1 was produced.

Protective layer coating solution / perfluoroalkoxy resin particles (MPE-056, manufactured by Mitsui Fluorochemicals)
: 5.5 parts ・ Dispersing aid (Modiper F210, manufactured by NOF Corporation): 1.0 part ・ Exemplary compound 2-2: 0.4 parts ・ Polycarbonate (Z Polyca, manufactured by Teijin Chemicals): 4 parts ・ Tetrahydrofuran: 200 Parts ・ Cyclohexanone: 60 parts

[Example 2]
An electrophotographic photosensitive member 2 was produced in the same manner as in Example 1 except that the protective layer coating solution was changed to the following composition.
Protective layer coating solution / perfluoroalkoxy resin particles (MPE-056, manufactured by Mitsui Fluorochemicals)
: 3.3 parts Dispersion aid (Modiper F210, manufactured by NOF Corporation): 1.0 parts Exemplified compound 2-2: 0.4 parts Polycarbonate (Z Polyca, manufactured by Teijin Chemicals): 6.4 parts Tetrahydrofuran : 200 parts ・ Cyclohexanone: 60 parts

[Example 3]
An electrophotographic photosensitive member 3 was produced in the same manner as in Example 1 except that the protective layer coating solution was changed to the following composition.
Protective layer coating solution / perfluoroalkoxy resin particles (MPE-056, manufactured by Mitsui Fluorochemicals)
: 7.4 parts Dispersion aid (Modiper F210, manufactured by NOF Corporation): 1.0 parts Exemplified compound 2-2: 0.4 parts Polycarbonate (Z Polyca, manufactured by Teijin Chemicals): 2.3 parts Tetrahydrofuran : 200 parts ・ Cyclohexanone: 60 parts

[Comparative Example 1]
A comparative electrophotographic photosensitive member 1 was produced in the same manner as in Example 1 except that the protective layer coating solution was changed to the following composition.
Protective layer coating solution / perfluoroalkoxy resin particles (MPE-056, manufactured by Mitsui Fluorochemicals)
: 3.0 parts-Dispersing aid (Modiper F210, manufactured by NOF Corporation): 1.0 part-Exemplified compound 2-2: 0.4 parts-Polycarbonate (Z Polyca, manufactured by Teijin Chemicals): 6.7 parts-Tetrahydrofuran : 200 parts ・ Cyclohexanone: 60 parts

[Comparative Example 2]
A comparative electrophotographic photosensitive member 2 was produced in the same manner as in Example 1 except that the protective layer coating solution was changed to the following composition. In Comparative Examples 1 and 2, the protective layer contains the compound represented by the general formula (A) or (B) and also contains fluororesin fine particles. However, it is an example showing a case where the volume fraction of the fluororesin fine particles is out of the scope of the present invention. Other comparative examples are examples in which the volume fraction of the fluororesin particles was changed variously, but examples in which the compounds of the general formulas (A) and (B) were not included were shown.
Protective layer coating liquid, perfluoroalkoxy resin particles (MPE-056, manufactured by Mitsui Fluorochemical)
: 7.8 parts Dispersing aid (Modiper F210, manufactured by NOF Corporation): 1.0 parts Exemplified compound 2-2: 0.4 parts Polycarbonate (Z Polyca, manufactured by Teijin Chemicals): 1.9 parts Tetrahydrofuran : 200 parts ・ Cyclohexanone: 60 parts

[Comparative Example 3]
A comparative electrophotographic photosensitive member 3 was produced in the same manner as in Example 1 except that the protective layer coating solution was changed to the following composition.
Protective layer coating liquid, perfluoroalkoxy resin particles (MPE-056, manufactured by Mitsui Fluorochemical)
: 5.5 parts-Dispersing aid (Modiper F210, manufactured by NOF Corporation): 1.0 parts-Polycarbonate (Z Polyca, manufactured by Teijin Chemicals): 4.2 parts-Tetrahydrofuran: 200 parts-Cyclohexanone: 60 parts

[Example 4]
An electrophotographic photosensitive member 4 was produced in the same manner as in Example 1 except that the perfluoroalkoxy resin particles in the protective layer coating solution were changed to tetrafluoroethylene resin particles (Lublon L-2, manufactured by Daikin). .

[Examples 5 to 16]
Electrophotographic photosensitive members 5 to 16 were produced in the same manner as in Example 1 except that the exemplified compound 2-2 in the protective layer coating solution was changed to the compounds shown in Table 11.

[Comparative Example 4]
A comparative electrophotographic photosensitive member 4 was produced in the same manner as in Example 1 except that the exemplified compound 2-2 in the protective layer coating solution was changed to the compound of the following (Comparative Compound 1).

[Comparative Example 5]
A comparative electrophotographic photoreceptor 5 was produced in the same manner as in Example 1 except that the exemplified compound 2-2 in the protective layer coating solution was changed to the compound of the following (Comparative Compound 2).

[Comparative Example 6]
A comparative electrophotographic photosensitive member 6 was produced in the same manner as in Example 1 except that the exemplified compound 2-2 in the protective layer coating solution was changed to the following (Comparative Compound 3). Comparative compound 3 is a compound in the case where m _{1 to} m ₄ are 0 at the same time in general formula (B).

<Toner Production Example 1>
(1) Preparation of monomer composition-Styrene monomer 70 parts-N-butyl methacrylate 30 parts-Polystyrene 5 parts-3,5-di-tert-butylsalicylic acid zinc salt 2 parts-Carbon black 6 parts The monomer mixture was dispersed and mixed with a ball mill for 24 hours to prepare a monomer composition.

(2) Granulation, polymerization A flask equipped with a stirrer, a thermometer, an inert gas introduction tube, and a porous glass tube with a pore diameter of 110,000 kg, a pore volume of 0.42 cc / g, 10φ × 50 mm, 2% 400 ml of an aqueous polyvinyl alcohol solution was taken and stirred at room temperature while feeding nitrogen gas to replace oxygen in the reaction vessel with nitrogen.
Next, after adding 1.56 g of azobisisobutyronitrile to 113 g of the monomer composition of (1) and stirring and dissolving it, it is passed through a porous glass tube using a pump and added to the aqueous polyvinyl alcohol solution, The mixture of the polyvinyl alcohol and the monomer composition was circulated at a rate of about 120 ml / min for 2 hours using the pump and the porous glass tube, and then the internal temperature was set to 70 ° C. and polymerized for 8 hours. It was.
After cooling to room temperature and allowing to stand overnight, the supernatant was removed, water was added and the mixture was stirred for 1 hour, then filtered and dried to obtain a toner. When the particle diameter of this toner was measured with a Coulter counter, the average particle diameter was 8.5 μm, and the particles in the range of 0 to 5 μm accounted for 95% of the total particle size, indicating a very narrow particle size distribution.

<Evaluation Example 1>
The suspension containing the toner particles obtained in Toner Production Example 1 is passed through an imaging unit detection zone on a flat plate, the particle image is optically detected by a CCD camera, and the perimeter of an equivalent circle having the same projected area is obtained. The average circularity, which is a value obtained by dividing by the perimeter of real particles, was evaluated. This value can be measured as an average circularity by a flow type particle image analyzer FPIA-2000. As a specific measurement method, a dispersant is added in 100 to 150 ml of water from which impure solids have been removed in advance. As a surfactant, preferably 0.1 to 0.5 ml of an alkylbenzene sulfonate, and about 0.1 to 0.5 g of a measurement sample is further added, and the suspension in which the sample is dispersed is about 1 with an ultrasonic disperser. It is obtained by performing dispersion treatment for ˜3 minutes and measuring the shape and distribution of the toner with the above apparatus at a dispersion concentration of 3000 to 10,000 / μl. As a result of the examination so far, it has been found that a toner having 0.960 or more is effective for forming a high-definition image having a reproducibility with an appropriate density, and more preferably an average circularity of 0.1. 980 to 1.000. The circularity of the toner prepared in Toner Production Example 1 was 0.98.

<Evaluation Example 2> (Secondary particle diameter, coating area ratio)
FE-SEM (S-4200 Scanning Electron Microscope, manufactured by Hitachi, Ltd.) was used for 10 arbitrary observation points on the surfaces of the obtained electrophotographic photoreceptors 1 to 16 and comparative electrophotographic photoreceptors 1 to 6. Using an image processing software (Image-Pro Plus), the number of fluorine fine particles (primary particles and agglomerated secondary particles), and each particle were photographed using an image processing software (Image-Pro Plus). The average diameter, area, and area ratio were analyzed, and the covering area ratio of particles having an average diameter of 0.3 to 1.5 μm was calculated.

<Evaluation Example 3> (Surface friction coefficient)
The surface friction coefficient of the obtained electrophotographic photosensitive members 1 to 16 and comparative electrophotographic photosensitive members 1 to 6 was evaluated by using the Euler belt method disclosed in JP-A-9-166919. Here, the belt is a medium-quality high-quality paper having a paper gap in the longitudinal direction (usually copy paper). As shown in FIG. 9, the surface friction coefficient is such that this belt is stretched around the circumference ¼ of the photoreceptor (shown as a sample in FIG. 9), a load of W = 100 g is applied to one of the belts, and the other is applied to the other. A force gauge (spring balance) was installed. Observe the belt movement while gradually pulling the force gauge, read the load at the start of movement, and calculate according to the following formula. In FIG. 9, a load: 100 g weight and a belt (Type 6200 / T direction / A4 paper / 30 mm width (cut in the gap direction): A4 paper (Type 6200) in the T direction are used, and the gap is 30 mm in width. And two double clips are used. In the equation, μ represents a friction coefficient, F represents a tensile force, and W represents a load.
μ = 2 / π × ln (F / W) (W = 100 g)

<Evaluation Example 4> (Durability Life A)
The obtained electrophotographic photoconductors 1 to 16 and comparative electrophotographic photoconductors 1 to 6 were converted from Ricoh's imgio Color 5100 remodeling machine (imagino Color color toner S [circularity 0.91], and an image exposure light source of 655 nm semiconductor The laser was replaced with a laser and the lubricant application means was removed, and a total of 100,000 sheets were printed continuously. At that time, the initial image and the image after 100,000 sheets were evaluated. Further, the light portion potential at the initial stage and after printing 100,000 sheets was measured. Further, the amount of wear was evaluated from the difference in film thickness at the initial stage and after printing 100,000 sheets.

<Evaluation Example 5> (Durable Life B)
The obtained electrophotographic photosensitive members 1 to 16 and comparative electrophotographic photosensitive members 1 to 6 were changed to Ricoh's imgio Color 5100 remodeling machine (the toner was changed to that prepared in Production Example 1, and the image exposure light source was a semiconductor laser having a wavelength of 655 nm. In addition, a total of 100,000 sheets were printed continuously, and the initial image and the image after 100,000 sheets were evaluated. Further, the light portion potential at the initial stage and after printing 100,000 sheets was measured. Further, the amount of wear was evaluated from the difference in film thickness at the initial stage and after printing 100,000 sheets.

<Evaluation Example 6> (Durable Life C)
The obtained electrophotographic photosensitive members 1 to 16 and comparative electrophotographic photosensitive members 1 to 6 are mounted on a Ricoh imagio Color 8100 remodeling machine (the toner is changed to that prepared in Production Example 1), and the total is continuously measured. 50,000 sheets were printed, and the initial image and the image after printing 50,000 sheets were evaluated. Further, the light portion potential at the initial stage and after printing 50,000 sheets was measured. Furthermore, the amount of wear was evaluated from the difference in film thickness at the initial stage and after printing 50,000 sheets.

The evaluation results of the durable lifetimes A to C are shown in Tables 11 to 13.
As can be seen from the evaluation results of Tables 11 and 12, the outermost surface layer of the photoreceptor contains 20 to 60% fluororesin fine particles in a volume fraction, thereby maintaining a highly stable and low surface friction coefficient. It became possible to do. Further, the amount of wear was also suppressed, and it was confirmed that the wear resistance was greatly improved. Further, it was confirmed that even after printing 100,000 sheets, the bright portion potential did not increase so much, and the photoconductor added with the exemplary compound did not generate afterimages and could stably obtain a high-quality image. On the other hand, a photoconductor containing no fluororesin fine particles with a volume fraction of 20 to 60% (Comparative Examples 1 and 2), a photoconductor without any exemplified compound (Comparative Example 3), and a compound specified in the present invention Photoconductors using compounds other than those (Comparative Examples 4, 5, and 6) caused cleaning defects and afterimages.
As can be seen from the evaluation results in Tables 12 to 13, even when spherical toner was used, the same tendency as in Tables 11 and 12 was observed.

It is a figure which shows the layer structural example of the electrophotographic photoreceptor of this invention. It is a figure which shows the other layer structural example of the electrophotographic photoreceptor of this invention. It is a figure which shows the other layer structural example of the electrophotographic photoreceptor of this invention. It is a figure which shows the structural example of the electrophotographic apparatus of this invention. It is a figure which shows the other structural example of the electrophotographic apparatus of this invention. It is a figure which shows the structural example of the process cartridge of this invention. It is a figure which shows the other structural example of the electrophotographic apparatus of this invention. It is a figure which shows the other structural example of the electrophotographic apparatus of this invention. It is a figure for demonstrating measuring the friction coefficient by the surface friction coefficient measuring apparatus of an Euler belt system.

Explanation of symbols

31 Conductive Support 33 Photosensitive Layer 35 Charge Generation Layer 37 Charge Transport Layer 39 Protective Layer

Claims (11)

In the electrophotographic photoreceptor having a protective layer containing fluororesin fine particles formed on the outermost surface layer,
The protective layer contains a fluororesin fine particle having a volume fraction of 20 to 60% and a compound represented by the following general formula (A).

[In the general formula (A), R1 to R4 each independently represents a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group, which may be the same or different. May be. However, any one of R1-R4 is the following general formula (Y)

It is group shown by. n ₁ ~n ₄ each independently represents 0 or the integer 1. m _{1 to} m ₄ each independently represents an integer of 0 to 3 (however, in the case of two or three, the groups 2 or 3 may be the same or different). However, m _{1 to} m ₄ are not 0 at the same time. Ar _{1 to} Ar ₁₀ represent a substituted or unsubstituted aromatic ring group, and may be the same or different. Ar ₁ to Ar ₂ adjacent to each other may form a ring together. a to b each independently represents an integer of 0 or 1 (in the general formula (Y), R5 and R6 may be the same or different, and each independently represents a substituted or unsubstituted alkyl group, substituted Or an unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted heterocyclic group bonded to each other at R5 and R6 and containing a nitrogen atom). ] In the electrophotographic photoreceptor having a protective layer containing fluororesin fine particles formed on the outermost surface layer,
The electrophotographic photoreceptor, wherein the protective layer contains fluororesin fine particles having a volume fraction of 20% to 60% and a compound represented by the following general formula (B).

[In said general formula (B), R1-R4 represents a substituted or unsubstituted C1-C50 alkyl group or a substituted or unsubstituted aromatic hydrocarbon group, and may be same or different. However, any one of R1-R4 is the following general formula (Y)

It is group shown by. n _{1 to} n ₄ each independently represents an integer of 0 or 1. m _{1 to} m ₄ each independently represents an integer of 0 to 3 (however, in the case of 2 or 3, the groups 2 or 3 may be the same or different). However, m _{1 to} m ₄ are not 0 at the same time. Ar ^{1 to} Ar ¹⁰ represent a substituted or unsubstituted aromatic ring group, and may be the same or different. Further, it may be linked to form a ring each Ar ₁ to Ar ₁₀ which are adjacent to each other. a to b each independently represents an integer of 0 or 1 (in the general formula (Y), R5 and R6 may be the same or different, and each independently represents a substituted or unsubstituted alkyl group, substituted Or an unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted heterocyclic group bonded to each other at R5 and R6 and containing a nitrogen atom). ]   3. An electrophotographic method comprising using the electrophotographic photosensitive member according to claim 1 or 2 and repeatedly performing at least charging, image exposure, development, and transfer on the electrophotographic photosensitive member.   The electrophotographic method is an electrophotographic method in which a cleaning process is further added to the process, and at least one of the charging process, the image exposure process, the development process, the transfer process, and the cleaning process. 4. The electrophotographic method according to claim 3, wherein a member is brought into contact with the photosensitive member and the surface of the photosensitive member is rubbed to adhere the fluororesin particles to the surface.   5. The digital electrophotographic method according to claim 3, wherein an electrostatic latent image is formed on a photosensitive member by LD or LED at the time of image exposure.   6. The electrophotographic method according to claim 3, wherein the toner used for image formation in the development is a substantially spherical toner.   An electrophotographic apparatus comprising at least a charging unit, an image exposing unit, a developing unit, a transferring unit, and the electrophotographic photosensitive member according to claim 1.   It comprises at least a charging means, an image exposing means, a developing means, a transferring means, and the electrophotographic photosensitive member according to claim 1, and uses an LD or an LED as the image exposing means, so A digital electrophotographic apparatus in which an electrostatic latent image is written.   9. The electrophotographic apparatus according to claim 7, wherein the electrophotographic apparatus is a tandem type having a plurality of sets of an electrophotographic photosensitive member, a charging unit, a developing unit, and a transfer unit.   The toner image developed on the electrophotographic photosensitive member is primarily transferred onto the intermediate transfer member, and then has an intermediate transfer means for secondary transfer of the toner image on the intermediate transfer member onto the recording material. 9. The electrophotographic apparatus according to claim 7, wherein a toner image is sequentially superimposed on the intermediate transfer member to form a color image, and the color image is secondarily transferred onto the recording material at once. apparatus.   A process cartridge for an electrophotographic apparatus, comprising: at least one of a charging unit, an exposure unit, a developing unit, a cleaning unit, and a transfer unit; and the electrophotographic photosensitive member according to claim 1.

Images