JP2005241981A - Electrophotographic photoreceptor, process cartridge and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which hardly gives rise to the degradation in electrostatic charge characteristics by long-term storage, has excellent potential stability in repetitive use, and has a longer service life, and a process cartridge having the electrophotographic photoreceptor, and an electrophotographic apparatus. <P>SOLUTION: The electrophotographic photoreceptor has a photosensitive on a support, wherein the surface layer of the electrophotographic photoreceptor contains a specific diorganopolysiloxane, fluorine atom-containing resin particulates, a polyarylate resin having a specific repeating structure, and a specific additive. The process cartridge and electrophotographic apparatus have such electrophotographic photoreceptor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member, and more particularly, to an electrophotographic photosensitive member containing a specific diorganopolysiloxane, fluorine atom-containing resin fine particles, a polyarylate resin having a specific repeating structural unit, and a specific additive in the surface layer of the photoconductor. And a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

  One typical example of the image holding member is an electrophotographic photosensitive member. In recent years, electrophotographic technology has been widely used and applied not only in the field of copying machines but also in the field of various printers because of its immediacy and high quality images. The core photoconductors include inorganic materials such as selenium, cadmium sulfide, and zinc oxide, but in recent years they are organic in terms of pollution-free, high productivity, ease of material design, and future prospects. System materials are being developed extensively.

  These electrophotographic photoreceptors are required to have electrical characteristics, mechanical characteristics, and optical characteristics according to the applied electrophotographic process. In particular, for electrophotographic photoreceptors that are repeatedly used, electrical and mechanical external forces such as charging, image exposure, toner development, transfer, and cleaning are repeatedly applied directly or indirectly, so durability is required. Is done.

  Unlike an inorganic photoreceptor, an electrophotographic photoreceptor containing an organic photoconductive material composed of a relatively soft material has poor durability against mechanical deterioration, and various attempts have been made to satisfy durability characteristics. It was.

  Among them, as a method of effectively preventing mechanical deterioration and improving durability, the friction coefficient on the surface of the electrophotographic photosensitive member is reduced by making fluorine atom-containing resin fine particles present in the surface layer of the electrophotographic photosensitive member. The method of making it include. With this configuration, the rubbing property with the cleaning member becomes smooth, and a strong shearing stress is not applied to the surface of the electrophotographic photosensitive member.

  However, generally, the fluorine atom-containing resin fine particles have a low surface tension, and it is difficult to uniformly disperse them in a resin having a relatively high surface tension. For this reason, attempts have been made to use various dispersion aids in combination, and a method for improving the dispersibility of fluorine atom-containing resin fine particles by using a specific polysiloxane has been proposed (for example, Patent Documents). 1).

Further, a method has been proposed for improving durability and potential stability by containing a fluorine atom-containing resin fine particle, a specific diorganopolysiloxane, and a polyarylate resin having a specific repeating structural unit (for example, , See Patent Document 2).
JP 2000-81715 A JP 2003-015326 A

  However, when fluorine atom-containing resin fine particles, specific diorganopolysiloxane, and polyarylate resin having specific repeating structural units are used, the durability and potential stability are improved, but the charging characteristics are improved by standing for a long time. It worsened and it sometimes became an image defect.

  Accordingly, an object of the present invention is to provide an electrophotographic photosensitive member that is excellent in durability and potential stability, and that does not cause image defects due to deterioration of charging characteristics even when left for a long time, and the electrophotographic photosensitive member. A process cartridge and an electrophotographic apparatus are provided.

That is, the present invention provides an electrophotographic photosensitive member having a photosensitive layer on a support, wherein the surface layer of the electrophotographic photosensitive member is at least
A diorganopolysiloxane having a repeating structural unit α represented by the following formula (11) and a repeating structural unit β represented by the following formula (12) and having a weight average molecular weight of 1,000 to 1,000,000;
Fluorine atom-containing resin fine particles,
Containing at least one of a polyarylate resin having a repeating structural unit represented by the following formula (2), a compound represented by the following formula (3), and a compound represented by the following formula (4), the formula (3), And the content of the compound represented by the formula (4) is 3% by mass or more and 6% by mass or less based on the total solid content of the surface layer.

（式（１１）および（１２）中、Ｒ^１１およびＲ^１２は、それぞれ独立に、置換または無置換の１価の炭化水素基を示し、Ｂ^１１は、パーフルオロアルキル基を有する１価の有機基を示し、Ｄ^１１は、重合度３以上の置換または無置換のポリスチレン鎖を有する１価の有機基、置換または無置換のアルキレンオキシ基を有する１価の有機基、置換または無置換のシロキサン鎖を有する１価の有機基、および、炭素原子数１２以上の１価の有機基からなる群より選択される１価の基を示す。）

(In the formulas (11) and (12), R ¹¹ and R ¹² each independently represents a substituted or unsubstituted monovalent hydrocarbon group, and B ¹¹ is a monovalent organic group having a perfluoroalkyl group. D ¹¹ represents a monovalent organic group having a substituted or unsubstituted polystyrene chain having a degree of polymerization of 3 or more, a monovalent organic group having a substituted or unsubstituted alkyleneoxy group, a substituted or unsubstituted siloxane A monovalent group selected from the group consisting of a monovalent organic group having a chain and a monovalent organic group having 12 or more carbon atoms.

（式中、Ｒ_２１〜Ｒ_２５は、水素原子、ハロゲン原子、置換もしくは無置換のアルキル基、アリール基またはアルコキシ基を示す。）

(Wherein R _{21 to} R ₂₅ represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an aryl group, or an alkoxy group.)

  The present invention also provides a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

  According to the electrophotographic photoreceptor of the present invention, by using a specific diorganopolysiloxane, fluorine atom-containing resin fine particles, a polyarylate resin having a specific repeating structural unit, and a specific additive for the surface layer of the photoconductor. In addition, the charging characteristics hardly deteriorated by long-term storage, good potential characteristics were obtained, and even better durability characteristics could be obtained. Further, a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member were obtained.

  The electrophotographic photoreceptor of the present invention has a repeating structural unit α represented by the following formula (11) and a repeating structural unit β represented by the following formula (12) and has a weight average molecular weight of 1,000 to 1,000,000. Contains siloxane. By containing this, the fluorine atom-containing resin fine particles can be uniformly dispersed while maintaining the potential stability in repeated use.

In the above formulas (11) and (12), R ¹¹ and R ¹² each independently represent a substituted or unsubstituted monovalent hydrocarbon group, and B ¹¹ is a monovalent organic group having a perfluoroalkyl group. D ¹¹ represents a monovalent organic group having a substituted or unsubstituted polystyrene chain having a degree of polymerization of 3 or more, a monovalent organic group having a substituted or unsubstituted alkyleneoxy group, a substituted or unsubstituted siloxane 1 represents a monovalent group selected from the group consisting of a monovalent organic group having a chain and a monovalent organic group having 12 or more carbon atoms.

  The diorganopolysiloxane may further have a repeating structural unit γ represented by the following formula (13).

In the above formula (13), R ¹³ and R ¹⁴ each independently represent a substituted or unsubstituted monovalent hydrocarbon group.

  Examples of the terminal group of the diorganopolysiloxane include a terminal group I having a structure represented by the following formula (14) and a terminal group II having a structure represented by the following formula (15).

In the above formulas (14) and (15), R ¹⁵ and R ¹⁶ each independently represent a substituted or unsubstituted monovalent hydrocarbon group, and E ¹¹ and E ¹² each independently represent a substituted or unsubstituted group. A substituted monovalent hydrocarbon group, a monovalent organic group having a perfluoroalkyl group, a monovalent organic group having a substituted or unsubstituted polystyrene chain having a polymerization degree of 3 or more, and a substituted or unsubstituted alkyleneoxy group. A monovalent group selected from the group consisting of a monovalent organic group having a monovalent organic group having a substituted or unsubstituted siloxane chain, and a monovalent organic group having 12 or more carbon atoms, E ¹¹ in the formula (14) is bonded to Si in the main chain (-Si-O-) of the repeating structural unit of the diorganopolysiloxane, and Si in the formula (15) is the diorgano Polyshiroki Emissions are combined with O in the backbone of repeating structural units (-Si-O-) with.

  In the present invention, the organic group means a substituted or unsubstituted hydrocarbon group. In addition, examples of the hydrocarbon group include an alkyl group, an alkenyl group, an aryl group, and an arylalkenyl group.

Examples of the monovalent hydrocarbon group for R ^{11 to} R ¹⁶ include a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted arylalkenyl group. Can be mentioned. These groups preferably have 1 to 30 carbon atoms, and more preferably a methyl group and a phenyl group.

The monovalent organic group having a B ¹¹ perfluoroalkyl group is preferably a monovalent group having a structure represented by the following formula (16).

In the above formula (16), R ²¹ represents an alkylene group or an alkylenecarbonyloxyalkylene group, and a represents an integer of 3 or more.

  Examples of the alkylene group include an ethylene group and a propylene group. Examples of the alkylenecarbonyloxyalkylene group include an ethylenecarbonyloxyethylene group, an ethylenecarbonyloxypropylene group, a propylenecarbonyloxypropylene group, and an ethylenecarbonyloxydekelene group.

A monovalent organic group having a polymerization degree of 3 or more substituted or unsubstituted polystyrene chain of the D ¹¹ is preferably a monovalent group having a structure represented by the following formula (17).

In the above formula (17), R ³¹ represents a substituted or unsubstituted divalent hydrocarbon group, and R ³² and R ³³ each independently represents a substituted or unsubstituted alkyl group, or a substituted or unsubstituted group. W ³¹ represents a substituted or unsubstituted polystyrene chain having a degree of polymerization of 3 or more, R ³⁴ represents a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, b Represents 0 or 1.

  As said bivalent hydrocarbon group, alkylene groups, such as a methylene group, ethylene group, a propylene group, are mentioned, It is preferable that it is C1-C10. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. The aryl group is preferably unsubstituted, and examples thereof include a phenyl group.

The monovalent organic group having a substituted or unsubstituted alkyleneoxy group of D ¹¹ is preferably a monovalent group having a structure represented by the following formula (18).

In the above formula (18), R ⁴¹ and R ⁴² each independently represent a substituted or unsubstituted divalent hydrocarbon group, and R ⁴³ represents a hydrogen atom or a substituted or unsubstituted monovalent carbon group. Represents a hydrogen group, c represents 0 or 1, and d represents an integer of 1 to 300.

  Examples of the divalent hydrocarbon group include alkylene groups such as a methylene group, an ethylene group, and a propylene group, and arylene groups such as a phenylene group. Examples of the monovalent hydrocarbon group include alkyl groups such as a methyl group, an ethyl group, and a propyl group, and aryl groups such as a phenyl group. The d is preferably 5 or more.

The monovalent organic group having a substituted or unsubstituted siloxane chain of D ¹¹ is preferably a monovalent group having a structure represented by the following formula (19).

In the above formula (19), R ⁵¹ represents an alkylene group, an alkyleneoxy group, or an oxygen atom, and R ^{52 to} R ⁵⁶ each independently represents a substituted or unsubstituted alkyl group, or a substituted or unsubstituted group. E represents an integer of 3 or more.

  Examples of the alkylene group include an ethylene group and a propylene group. Examples of the alkyleneoxy group include an ethyleneoxy group and a propyleneoxy group. Examples of the alkyl group include a methyl group and an ethyl group. Examples of the aryl group include a phenyl group. The e is preferably 5 or more.

Examples of the monovalent organic group having 12 or more carbon atoms of D ¹¹ include alkyl groups such as n-dodecyl group, n-tetradodecyl group, n-hexadecyl group, and n-octadecyl group. The number of carbon atoms is preferably 100 or less.

  Examples of the substituent that each of the above groups may have include a halogen atom such as a fluorine atom, a chlorine atom and an iodine atom, an alkyl group such as a methyl group, an ethyl group and a propyl group, and an aryl group such as a phenyl group. Can be mentioned.

  The number (average) of the repeating structural units α represented by the above formula (11) in the diorganopolysiloxane is preferably 1 to 1000, and more preferably 10 to 200.

  The number (average) of the repeating structural units β represented by the above formula (12) in the diorganopolysiloxane is preferably 1 to 1000, more preferably 5 to 100.

  The number (average) of repeating structural units γ represented by the above formula (13) in the diorganopolysiloxane is preferably 0 to 1000, and more preferably 100 to 200.

  The repeating structural unit possessed by the diorganopolysiloxane is only the repeating structural unit α represented by the above formula (11) and the repeating structural unit β represented by the above formula (12), or the repeating structural unit represented by the above formula (11). It is preferable that there are only the structural unit α, the repeating structural unit β represented by the above formula (12), and the repeating structural unit γ represented by the above formula (13).

  Sum (average) of the repeating structural unit α represented by the above formula (11), the repeating structural unit β represented by the above formula (12) and the repeating structural unit γ represented by the above formula (13) in the diorganopolysiloxane. Is preferably from 2 to 2000, more preferably from 5 to 1000, and even more preferably from 20 to 500.

When the number of repeating structural units α represented by the above formula (11) is 2 or more, the plurality of R ¹¹ may be the same group or two or more different groups, and the plurality of B ¹¹ are the same. Or two or more different groups.

When the number of repeating structural units β represented by the above formula (12) is 2 or more, the plurality of R ¹² may be the same group or two or more different groups, and the plurality of D ¹¹ are the same. Or two or more different groups. D ¹¹ is a monovalent organic group having a substituted or unsubstituted polystyrene chain having a polymerization degree of 3 or more, a monovalent organic group having a substituted or unsubstituted alkyleneoxy group, a substituted or unsubstituted siloxane, as described above. Any one of a monovalent organic group having a chain and a monovalent organic group having 12 or more carbon atoms, and when there are a plurality of D ¹¹ , at least one D ¹¹ is a substituted or unsubstituted group. A monovalent organic group having a siloxane chain is preferred.

When the number of repeating structural units γ represented by the above formula (13) is 2 or more, the plurality of R ¹³ may be the same group or two or more different groups, and the plurality of R ¹⁴ are the same. Or two or more different groups.

The same applies to R ³² and R ^{33 in} the above formula (17), R ^{42 in} the above formula (18), and R ⁵² and R ⁵³ in the above formula (19).

Below, the specific example of the diorganopolysiloxane used for this invention is shown. However, the present invention is not limited to these specific examples. In addition, the following diorganopolysiloxanes (1-1) to (1-23) all have a terminal group I (E ¹¹ : methyl group) having the structure represented by the above formula (14) as a terminal group and the above formula. terminal group ^II having a structure represented by ^{(15) (E 12, R} 15 and ^{R 16:} methyl) having a.

  Among these, (1-1), (1-4), (1-5), (1-7), (1-10), (1-14), (1-15), (1- 22) is preferable, and (1-1), (1-5), (1-10), and (1-22) are particularly preferable.

  The weight average molecular weight of the diorganopolysiloxane used in the present invention is 1000 to 1000000, preferably 10,000 to 200000, more preferably 10,000 to 100,000, and more preferably 20000 to 40000. Is more preferable.

  Moreover, it is preferable that content of the fluorine atom in the diorganopolysiloxane used for this invention is 1-90 mass% with respect to the diorganopolysiloxane total mass, and is 5-60 mass% especially. It is preferable. If the fluorine atom content is less than 1% by mass, the releasability of the surface layer of the electrophotographic photosensitive member may not be sufficiently exhibited. If it exceeds 90% by mass, the binding in the surface layer of the electrophotographic photosensitive member may not be achieved. The compatibility with the resin may deteriorate.

  Fluorine atom-containing resin fine particles include tetrafluoroethylene resin, trifluoroethylene chloride resin, tetratetrafluoroethylene hexafluoroethylenepropylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodiethylene chloride resin and Particles such as these copolymer resins are listed. Among these, tetrafluoroethylene resin (polytetrafluoroethylene) is particularly preferable.

  Further, the particle diameter is preferably 0.05 to 0.5 μm in volume average particle diameter, and particularly preferably 0.1 to 0.4 μm.

  The content of the diorganopolysiloxane represented by the formula (1) is preferably 0.1 to 30 parts by mass, particularly preferably 3 to 15 parts by mass with respect to 100 parts by mass of the fluorine atom-containing resin fine particles. If the content is too small, it is difficult to obtain an effect on dispersibility. If the content is too large, carrier traps are caused and potential fluctuations are likely to occur. In addition, when diorganopolysiloxane, fluorine atom-containing resin fine particles and binder resin are dispersed in advance, it is possible to disperse even if the amount of binder resin is equal to or less than the mass part of fluorine atom-containing resin fine particles. When the amount is preferably equal or more, more preferably 1.5 times or more, a better dispersion state can be obtained.

  The content of the fluorine atom-containing resin fine particles in the surface layer is preferably 0.5 to 30 parts by mass with respect to 100 parts by mass as a whole of the surface layer. If the amount is less than 0.5 parts by mass, the effect of abrasion resistance is small, and if it exceeds 30 parts by mass, the light transmission may be reduced or scattered, and the electrophotographic characteristics may be adversely affected.

In formula (2), the alkyl group of R _{21 to} R ₂₅ preferably has 1 to 5 carbon atoms. Examples of the aryl group include a phenyl group, a tolyl group, and a xylyl group, and an alkoxy group has 1 carbon atom. It is preferable that it is -5, and a fluorine atom, chlorine, and a bromine are mentioned as a halogen atom. It is preferable that at least one of R _{21 to} R ₂₄ is a methyl group.

  Specific examples of the repeating structural unit possessed by the polyarylate resin represented by the formula (2) are shown below, but this is an example and does not limit the present invention.

  Among these, (2-2), (2-3), (2-4) and (2-7) are preferable, and (2-2) and (2-3) are particularly preferable.

  In the present invention, for the purpose of solubility in a solvent, compatibility with a charge transport material, and the like, a polyarylate resin is composed of a repeating structural unit represented by the formula (2) and a repeating structural unit represented by the following formula (5). It is preferable to use a copolymer having

  The present invention exhibits an effect by containing at least the repeating structural unit shown above, and can be used by copolymerizing with the polyarylate represented by the formula (5).

（Ｒ_５１〜Ｒ_５４は、水素原子、ハロゲン原子、置換もしくは無置換のアルキル基、アリール基、アルコキシ基を示す。また、Ｒ_５５およびＲ_５６は水素原子、ハロゲン原子、置換もしくは無置換のアルキル基、アリール基およびＲ_５５とＲ_５６が結合することによって形成するアルキリデン基を示す。）

(R _{51 to} R ₅₄ represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an aryl group or an alkoxy group. R ₅₅ and R ₅₆ represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group. A group, an aryl group, and an alkylidene group formed by combining R ₅₅ and R _56. )

  Specific examples of the repeating structural unit represented by the formula (5) are shown below.

  When the polyarylate represented by the formula (2) and the polyarylate represented by the formula (5) are copolymerized, the repeating structural units of the polyarylate represented by the formula (5) are (5-2), (5- 3) and (5-6) are preferable. The copolymerization ratio (mass) is preferably {polyarylate represented by formula (2) / polyarylate represented by formula (5)} = 1/9 to 8/2, particularly 2/8 to 7 /. 3 is preferred. Moreover, in the case of copolymerization, it can also be set as a multi-component copolymer using 2 or more types in Formula (5) or different bisphenol structures. In the copolymerization, the ratio of the formula (2) is preferably 1 part by mass or more when the total mass of the resin is 10 parts by mass.

  The weight average molecular weight of the polyarylate resin used in the present invention is preferably 100,000 or more.

  In this invention, at least one of the compound shown by Formula (3) and Formula (4) is contained. As a result, it is possible to effectively suppress deterioration of charging characteristics due to long-term standing, and to maintain potential stability in repeated use. The deterioration of the charging characteristics due to long-term storage occurs particularly remarkably when the amount of the binder resin and fluorine atom-containing resin fine particles is large. Specifically, the amount of the binder resin and the fluorine atom-containing resin fine particles is particularly prominent when the amount is 60% by mass or more based on the total solid content, but the compounds represented by the formulas (3) and (4) By adding at least one of the above, it is possible to effectively suppress deterioration of charging characteristics due to long-term storage.

  Content of the compound shown by Formula (3) and Formula (4) is 3 mass% or more and 6 mass% or less with respect to the total solid, and 3.5 mass% or more and 6 mass% or less are preferable. If the addition amount is less than 3% by mass, deterioration of charging characteristics due to long-term standing cannot be suppressed, and if the content exceeds 6% by mass, potential fluctuation occurs in repeated use.

  The compounds of formula (3) and formula (4) may be used alone or in combination. Furthermore, you may add another additive as needed.

  The surface layer described in the present invention is a charge transport layer in the case of a normal negatively chargeable laminated photoreceptor, and may be a protective layer formed thereon.

  Hereinafter, the configuration of the electrophotographic photoreceptor of the present invention will be described. The electrophotographic photoreceptor of the present invention has a photosensitive layer on a support. The photosensitive layer may be a single layer type containing a charge transport material and a charge generation material in the same layer, or may be a laminated type having a charge transport layer containing a charge transport material and a charge generation layer containing a charge generation material. However, the laminate type is preferable from the electrophotographic characteristics.

  The support is only required to have conductivity, and examples thereof include metals such as aluminum and stainless steel, metals provided with a conductive layer, paper, plastics, and the like, and the shape includes a sheet shape and a cylindrical shape.

  In the present invention, a conductive layer may be provided between the support and the photosensitive layer for the purpose of preventing interference fringes and covering scratches on the support. This conductive layer can be formed by dispersing conductive particles such as carbon black and metal particles in a binder resin. It is also effective to add an appropriate amount of silica fine particles in order to suppress interference fringes. The film thickness of the conductive layer is preferably 0.1 to 40 μm, more preferably 0.5 to 25 μm. In addition, the support surface can be cut, roughened, anodized, etc. to suppress interference fringes.

  An intermediate layer having a layer adhesion function and a charge barrier function may be provided on the support or the conductive layer. Examples of the material for the intermediate layer include polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose, casein, polyurethane, and polyether urethane. These are applied after being dissolved in a suitable solvent. The thickness of the intermediate layer is preferably 0.05 to 5 μm, more preferably 0.3 to 1.5 μm.

  The charge generation material used in the present invention is not particularly limited. And asymmetric quinocyanine pigments.

  In the case of the function separation type, the charge generation layer is dispersed by a method such as a binder resin and an attritor, a roll mill, and a liquid collision type high-speed disperser in an amount of 0.3 to 4 times by mass. A photosensitive layer is formed by applying and drying the dispersion. However, depending on the characteristics of the charge generation material, the binder resin may be added after being dispersed with a solvent and the charge generation material, or the binder resin may not be used. The film thickness of the charge generation layer is preferably 5 μm or less, more preferably 0.1 to 2 μm.

  The charge transport layer mainly comprises a charge transport material and a binder resin. When the charge transport layer is a surface layer, at least one of the compounds represented by formula (3) and formula (4), and the following formula (11): A diorganopolysiloxane having a repeating structural unit α and a repeating structural unit β represented by the following formula (12) and having a weight average molecular weight of 1,000 to 1,000,000 is dissolved in a solvent, and further fluorine atom-containing resin fine particles It is formed by applying and drying a paint obtained by dispersing. Examples of the charge transport material used include triarylamine compounds, hydrazine compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, triallylmethane compounds, and thiazole compounds.

  Binders used in the charge transport layer include phenoxy resin, polyacrylamide resin, polyvinyl butyral resin, polyarylate resin, polysulfone resin, polyamide resin, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenol resin An epoxy resin, a polyester resin, an alkyd resin, a polyurethane resin, or a copolymer containing two or more repeating units of these resins, such as a styrene-butadiene copolymer, a styrene-acrylonitrile copolymer, and a styrene-maleic acid copolymer. be able to. Moreover, although it can also select from organic photoconductive polymers, such as poly-N-vinyl carbazole, polyvinyl anthracene, and polyvinyl pyrene, when a charge transport layer is a surface layer, it has a repeating structural unit shown by Formula (2). Polyarylate resin is used.

  The film thickness of the charge transport layer is preferably 5 to 50 μm, more preferably 10 to 35 μm. The ratio (mass) of the charge transport material and the binder resin is preferably about 5/1 to 1/5, more preferably about 3/1 to 1/3. Examples of the application method include general methods such as dip coating, spray coating, blade coating and roll coating.

  Mixing devices such as homogenizers, line mixers, ultradispersers, homomixers, liquid collision type high-speed dispersers, ultrasonic dispersers, and other emulsifiers, dispersers, and mixers can be used to disperse fluorine atom-containing resin fine particles. .

  FIG. 1 shows a schematic configuration of an electrophotographic apparatus having the electrophotographic photosensitive member of the present invention.

  In FIG. 1, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is rotationally driven around a shaft 2 in the direction of an arrow at a predetermined peripheral speed. In the rotation process, the photosensitive member 1 is uniformly charged with a positive or negative predetermined potential on its peripheral surface by the primary charging unit 3, and then exposed from an exposure unit (not shown) such as slit exposure or laser beam scanning exposure. Receive light 4. In this way, electrostatic latent images are sequentially formed on the peripheral surface of the photoreceptor 1.

  The formed electrostatic latent image is then developed with toner by the developing unit 5, and the developed toner developed image is rotated between the photosensitive member 1 and the transfer unit 6 from a sheet feeding unit (not shown). The image is sequentially transferred by the transfer means 6 to the transfer material 7 that is synchronously taken out and fed.

  The transfer material 7 that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means 8, and subjected to image fixing, thereby being printed out as a copy (copy).

  After the image transfer, the surface of the photoreceptor 1 is cleaned by removing the transfer residual toner by the cleaning unit 9, and is further subjected to charge removal processing by the pre-exposure light 10 from the pre-exposure unit (not shown). Used repeatedly for image formation. When the primary charging unit 3 is a contact charging unit using a charging roller or the like, pre-exposure is not always necessary.

  In the present invention, a plurality of components such as the above-described electrophotographic photosensitive member 1, primary charging unit 3, developing unit 5, and cleaning unit 9 are integrally coupled as a process cartridge. May be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. For example, at least one of the primary charging unit 3, the developing unit 5, and the cleaning unit 9 is integrally supported together with the photosensitive member 1 to form a cartridge, and is detachable from the apparatus main body using guide means such as a rail 12 of the apparatus main body. The process cartridge 11 can be obtained.

  Further, when the electrophotographic apparatus is a copying machine or a printer, the exposure light 4 is reflected or transmitted light from the original, or the original is read by a sensor and converted into a signal, and a laser beam scanning performed according to this signal is performed. The light is emitted by driving the LED array and the liquid crystal shutter array.

  The electrophotographic photosensitive member of the present invention can be used not only in electrophotographic copying machines but also widely in electrophotographic application fields such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making.

  Hereinafter, it demonstrates according to an Example. “Part” means part by mass.

  First, the diorganopolysiloxane used in the present invention can be synthesized as follows.

(Synthesis Example 1)
In a flask, 3.23 g of polysiloxane having the following repeating structural units α, β, γ,

塩化白金酸２０ｐｐｍ（５％イソプロピルアルコール溶液）と、下記式で示される構造を有するポリスチレン（ｎ：平均２５）１８．９ｇと、

20 ppm of chloroplatinic acid (5% isopropyl alcohol solution), polystyrene having a structure represented by the following formula (n: average 25) 18.9 g,

ｍ−キシレンヘキサフルオライド８０ｇとを混合し、徐々に加熱した。さらに、８０℃で６時間反応を続けた。次いで、１４０℃の条件下で２０Ｔｏｒｒまで減圧して、溶媒や低沸点成分を除去した。

80 g of m-xylene hexafluoride was mixed and gradually heated. Further, the reaction was continued at 80 ° C. for 6 hours. Subsequently, the pressure was reduced to 20 Torr under the condition of 140 ° C. to remove the solvent and low boiling point components.

Thus, when the obtained reaction product was analyzed by < ²⁹ > Si-NMR, < ¹³ > C-NMR, and FT-IR, it became clear that it was diorganopolysiloxane (1-1).

  Diorganopolysiloxanes used in the present invention having other structures can be synthesized in the same manner as in Synthesis Example 1.

(Example 1)
An aluminum cylinder having a diameter of 30 mm and a length of 357 mm was ultrasonically cleaned with a water-based cleaning agent, immersed in ion exchange water at 80 ° C., and then pulled up to obtain a dry and clean surface. On this support, a coating material composed of the following materials was applied by a dip coating method and thermally cured at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm.

Conductive pigment: SnO _2- coated barium sulfate 10 parts Resistance adjusting pigment: Titanium oxide 2 parts Binder resin: Phenol resin 6 parts Leveling agent :; Silicone oil 0.001 part Solvent: Methanol, methoxypropanol 0.2 / 0. 8 20 copies

  Next, a solution obtained by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon in a mixed solvent of 65 parts of methanol and 30 parts of n-butanol is applied on this conductive layer by a dip coating method and dried. Thus, an intermediate layer having a film thickness of 1.0 μm was formed.

  Next, 4 parts of a charge generation material (CGM-1) represented by the following structure and 70 parts of tetrahydrofuran are dispersed for 10 hours in a sand mill apparatus using glass beads having a diameter of 1 mm, and then a polyvinyl butyral resin (ESREC BLS, Sekisui Chemical Co., Ltd.). A solution prepared by dissolving 2 parts in 20 parts of tetrahydrofuran was added and dispersed for another 2 hours. Further, the glass beads were separated, and 100 parts of cyclohexanone was added to prepare a dispersion for the charge generation layer. This dispersion was applied onto the intermediate layer by a dip coating method and dried at 80 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

Next, a coating for the charge transport layer was prepared in order to form the charge transport layer. First, 10 parts of a polyarylate resin having a repeating structural unit represented by the following formula (weight average molecular weight (Mw) = 120,000, mass ratio of terephthalic acid to isophthalic acid in the resin: terephthalic acid / isophthalic acid = 50/50) Dissolve in 100 parts of monochlorobenzene, 10 parts of polytetrafluoroethylene resin particles (Lublon L-2: manufactured by Daikin Industries), 1 part of diorganopolysiloxane represented by the formula (1-1) shown in Synthesis Example 1 Added. This mixture was dispersed three times using a liquid collision disperser (Nanomizer, dispersion pressure 600 bar) to prepare a fluorine atom-containing resin fine particle dispersion. The dispersed fluorine atom-containing resin fine particles were measured in tetrahydrofuran with a solvent viscosity of 0.51 cP, a solvent density of 0.89 g / cm ³ , and a sample density of 2.17 g / cm ^{3 using} a particle size distribution analyzer (CAPA700, manufactured by Horiba, Ltd.). When measured, the volume average particle diameter was 0.21 μm.

  Next, 7 parts of a charge transport material represented by the following formula:

1.5 parts of a charge transport material represented by the formula:

Compound represented by formula (3) 1 part Polyarylate resin 12 parts Polytetrafluoroethylene resin fine particles 2.5 parts Diorganopolysiloxane 0.25 parts Monochlorobenzene 80 parts Dimethoxymethane 40 parts Prepared.

  As the polytetrafluoroethylene resin fine particles, the fluorine atom-containing resin fine particle dispersion previously dispersed was used. This paint was applied by a dip coating method and dried at 130 ° C. for 1 hour to form a charge transport layer having a thickness of 25 μm.

  Next, evaluation will be described.

  As an apparatus to be evaluated, a copying machine GP-55 manufactured by Canon Inc. was used. The initial potential was measured after replacing the photoconductor for evaluation. The dark part potential Vd = −700V and the bright part potential Vl = −200V. The surface potential of the electrophotographic photosensitive member was measured by removing the developing cartridge from the evaluator and inserting a potential measuring device there. The potential measuring device is configured by arranging a potential measuring probe at the developing position of the developing cartridge. The position of the potential measuring probe with respect to the electrophotographic photosensitive member is approximately the center in the drum axis direction, and a gap from the drum surface is formed. It was 3 mm.

  Next, the electrophotographic photosensitive member was left in a dark place for 2 months in an atmosphere of 23 ° C./50% RH, and then the potential was measured under the same conditions as the initial potential measurement.

  Next, in a continuous mode in which A4 size plain paper is continuously copied, an image with a printing ratio of 3% is copied 5,000 sheets in an atmosphere of 33 ° C./85% RH, and 5,000 copies are made. Later dark potential and bright potential were measured. In addition, after continuous copying, the image was output after being left for 24 hours, and it was confirmed whether or not image blur occurred. The evaluation of the image blur was performed visually. The case where the occurrence of the image blur could not be confirmed was indicated as “◯”, the case where the image blur was slightly generated was indicated as “Δ”, and the case where the image blur was clearly generated was indicated as “X”.

  The evaluation of the potential fluctuation was performed by measuring the surface potential after the initial and repeated copying, and examining the difference in dark portion potential (ΔVd) and the difference in bright portion potential (ΔVl). Note that (absolute value of potential after repeated copying) − (absolute value of initial potential) is ΔVd and ΔVl.

  Furthermore, in an intermittent mode in which A4-size plain paper is stopped once for each copy, an image with a print ratio of 3% is copied 50,000 sheets in an atmosphere of 33 ° C./85% RH before copying. The amount of wear of the electrophotographic photosensitive member was measured from the difference between the film thickness of the film and the film thickness after copying 50,000 sheets. The evaluation results are shown in Table 2.

  As an apparatus to be evaluated, a copying machine GP-405 manufactured by Canon Inc. was used. The initial potential was measured after replacing the photoconductor for evaluation. The dark part potential Vd = −700V and the bright part potential Vl = −200V. The surface potential of the electrophotographic photosensitive member was measured by removing the developing cartridge from the evaluator and inserting a potential measuring device there. The potential measuring device is configured by arranging a potential measuring probe at the developing position of the developing cartridge. The position of the potential measuring probe with respect to the electrophotographic photosensitive member is approximately the center in the drum axis direction, and a gap from the drum surface is formed. It was 3 mm.

  Next, the electrophotographic photosensitive member was left in a dark place for 2 months in an atmosphere of 23 ° C./50% RH, and then the potential was measured under the same conditions as the initial potential measurement.

  Next, in a continuous mode in which A4 size plain paper is continuously copied, an image with a printing ratio of 3% is copied 5,000 sheets in an atmosphere of 33 ° C./85% RH, and 5,000 copies are made. Later dark potential and bright potential were measured.

  The evaluation of the potential fluctuation was performed by measuring the surface potential after the initial and repeated copying, and examining the difference in dark portion potential (ΔVd) and the difference in bright portion potential (ΔVl). Note that (absolute value of potential after repeated copying) − (absolute value of initial potential) is ΔVd and ΔVl.

  Furthermore, in an intermittent mode in which A4 size plain paper is stopped once for each copy, an image with a print ratio of 3% is copied on 30,000 sheets in an atmosphere of 33 ° C / 85% RH before copying. The amount of wear of the electrophotographic photosensitive member was measured from the difference between the film thickness of the film and the film thickness after copying 30,000 sheets. The evaluation results are shown in Table 3.

(Example 2)
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the additive represented by formula (4) was used instead of the compound represented by formula (3) used in Example 1.

(Example 3)
Instead of the compound represented by formula (3) used in Example 1, the compound represented by formula (3) and formula (4) was used so that formula (3) / formula (4) = 1/1. A photoreceptor was prepared and evaluated in the same manner as in Example 1 except that.

Example 4
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the compound represented by the formula (3) used in Example 1 was changed to 0.84 part.

(Example 5)
A photoconductor was prepared and evaluated in the same manner as in Example 4 except that 0.72 parts of the compound represented by the formula (3) used in Example 4 was used.

(Example 6)
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the compound represented by the formula (3) used in Example 1 was changed to 1.48 parts.

(Example 7)
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the diorganopolysiloxane represented by formula (1-5) was used instead of the diorganopolysiloxane used in Example 1.

(Example 8)
Instead of the polyarylate resin used in Example 1, a polyarylate resin represented by the following formula (weight average molecular weight (Mw) = 120,000, mass ratio of terephthalic acid to isophthalic acid in the resin: terephthalic acid / isophthalic acid = 50 A photoconductor was prepared and evaluated in the same manner as in Example 1 except that / 50) was used.

Example 9
Instead of the polyarylate resin used in Example 1, a polyarylate resin represented by the following formula (weight average molecular weight (Mw) = 120,000, mass ratio of terephthalic acid to isophthalic acid in the resin: terephthalic acid / isophthalic acid = 50 A photoconductor was prepared and evaluated in the same manner as in Example 1 except that / 50) was used.

(Comparative Example 1)
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the compound represented by the formula (3) was not used.

(Comparative Example 2)
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the compound represented by the formula (3) used in Example 1 was changed to 0.5 part.

(Comparative Example 3)
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the compound represented by the formula (3) used in Example 1 was changed to 1.65 parts.

(Comparative Example 4)
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the compound represented by the following formula was used instead of the compound represented by the formula (3) used in Example 1.

(Comparative Example 5)
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the compound represented by the following formula was used instead of the compound represented by the formula (3) used in Example 1.

(Reference Example 1)
A photoconductor was prepared and evaluated in the same manner as in Comparative Example 1 except that the fluorine atom-containing resin fine particles used in Comparative Example 1 were not used.

(Reference Example 2)
In place of the polyarylate resin used in Comparative Example 1, a photoconductor was prepared in the same manner as in Comparative Example 1 except that a polycarbonate resin having a repeating structural unit represented by the following formula (weight average molecular weight (Mw) = 14000) was used. Prepared and evaluated.

(Reference Example 3)
Instead of the polyarylate resin used in Comparative Example 1, a polyarylate resin having a repeating structural unit represented by the following formula (weight average molecular weight (Mw) = 120,000, mass ratio of terephthalic acid and isophthalic acid in the resin: terephthalic acid A photoconductor was prepared and evaluated in the same manner as in Comparative Example 1 except that / isophthalic acid = 50/50) was used.

(Reference Example 4)
A photoconductor was prepared and evaluated in the same manner as in Comparative Example 1 except that an acrylic resin having a fluorinated alkyl side chain (GF300, manufactured by Toagosei Co., Ltd.) was used instead of the diorganopolysiloxane used in Comparative Example 1.

1 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus having the electrophotographic photosensitive member of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 of this invention Axis 3 Primary charging means 4 Exposure light 5 Developing means 6 Transfer means 7 Transfer material 8 Image fixing means 9 Cleaning means 10 Pre-exposure light 11 Process cartridge 12 Rail

Claims (3)

In the electrophotographic photosensitive member having a photosensitive layer on the support, the surface layer of the electrophotographic photosensitive member is at least:
A diorganopolysiloxane having a repeating structural unit α represented by the following formula (11) and a repeating structural unit β represented by the following formula (12) and having a weight average molecular weight of 1,000 to 1,000,000;
Fluorine atom-containing resin fine particles,
Containing at least one of a polyarylate resin having a repeating structural unit represented by the following formula (2), a compound represented by the following formula (3), and a compound represented by the following formula (4), the formula (3), And an electrophotographic photoreceptor, wherein the content of the compound represented by the formula (4) is 3% by mass or more and 6% by mass or less based on the total solid content of the surface layer.

(In the formulas (11) and (12), R ¹¹ and R ¹² each independently represents a substituted or unsubstituted monovalent hydrocarbon group, and B ¹¹ is a monovalent organic group having a perfluoroalkyl group. D ¹¹ represents a monovalent organic group having a substituted or unsubstituted polystyrene chain having a polymerization degree of 3 or more, a monovalent organic group having a substituted or unsubstituted alkyleneoxy group, a substituted or unsubstituted siloxane This represents a monovalent group selected from the group consisting of a monovalent organic group having a chain and a monovalent organic group having 12 or more carbon atoms.)

(Wherein R _{21 to} R ₂₅ represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an aryl group, or an alkoxy group.)

  The electrophotographic photosensitive member according to claim 1 and at least one means selected from the group consisting of a charging means, a developing means and a cleaning means are integrally supported, and are detachable from the main body of the electrophotographic apparatus. Process cartridge.   An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1, a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit.

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