JP2007108240A - Electrophotographic photoreceptor, process cartridge and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which has good durability when repeatedly used, and hardly causes deterioration of sensitivity even in the case of using short-wavelength light, particularly light having a wavelength of 380-450 nm as exposure light. <P>SOLUTION: The electrophotographic photoreceptor is obtained by stacking on a conductive support a charge generating layer and a charge transport layer in this order from the support side, and has a polyarylate resin having a specific structural unit represented by formula (1), a charge transport material and fluorine atom-containing resin fine particles in the charge transport layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  Photoconductive materials (charge generating materials and charge transport materials) used for electrophotographic photoreceptors mounted on electrophotographic apparatuses include inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide. Organic photoconductive substances have been actively developed from the viewpoints of pollution-free, high productivity, ease of material design and future prospects.

  These electrophotographic photoreceptors are naturally required to have various characteristics such as electrical, mechanical and optical characteristics according to the applied electrophotographic process. In particular, in a photoreceptor that is used repeatedly, electrical and mechanical forces such as charging, exposure, development, transfer, and cleaning are repeatedly applied directly or indirectly, so that stable characteristics can be obtained. Therefore, high durability that can withstand these is required.

  Furthermore, in an apparatus using an electrophotographic system, higher speed, higher image quality, and higher stability are required at a higher level from now to the future. With the speeding up of such a system, the photoreceptor is charged with the high-speed processes of charging, exposure, development, transfer, and cleaning, which are system components, and the primary charger, developer, transfer charging, which are system components. Since the photoconductor surface changes due to wear on the photoconductor surface due to contact with a contact portion such as a cleaning device or a cleaning device in a high speed state, the surface layer is strongly required to be improved in strength and durability. Many attempts have been made to improve.

  Among them, as a technique for improving wear resistance, there is a technique using a binder resin having excellent strength and lubricity for the surface layer, and Patent Documents 1 and 2 disclose a method using a high-strength resin. Patent Document 3 discloses a technique using a polyarylate resin having a special structure having a lubrication unit. Further, Patent Documents 4, 5 and 6 disclose a technique for obtaining better strength and lubricity by including fluorine atom-containing resin fine particles. Patent Document 7 discloses a material that improves the dispersibility of fluorine atom-containing resin fine particles in the photosensitive layer. Among these disclosures, the method of dispersing the fluorine atom-containing resin fine particles in the photosensitive layer is one of the most effective methods in terms of improving the abrasion resistance of the photoreceptor. However, in order to uniformly disperse the fluorine atom-containing resin fine particles in the photosensitive layer, a dispersant such as a fluorine atom-containing comb-type graft polymer or a diorganopolysiloxane having a fluoroalkyl group is currently required. Since these dispersants may cause adverse effects such as an increase in residual potential and potential fluctuation in repeated use, improvement is desired.

  As for the improvement of image quality, in recent years, in order to further increase the resolution of an output image, as exposure light (image exposure light) irradiated to an electrophotographic photosensitive member, light having a shorter wavelength than conventionally used light (image exposure light) For example, it has been proposed to use light having a wavelength of 380 to 450 nm (Patent Document 8, etc.).

  In addition, since the transmittance of the layer with respect to the exposure light affects the sensitivity of the electrophotographic photosensitive member, for example, Patent Document 9 discloses that a charge transport layer of a laminated type (normal layer type) photosensitive layer is exposed to a short wavelength exposure light. And a layer having a high transmittance is disclosed. Specifically, by using a compound having a specific structure as a charge transport material and using a polycarbonate resin (bisphenol Z-type polycarbonate) as a binder resin, a charge transport layer having a high transmittance for exposure light with a short wavelength is formed. ing.

However, the electrophotographic photoreceptor disclosed in Patent Document 9 has a high transmittance for short-wavelength light on its surface layer (charge transport layer), and uses short-wavelength light as exposure light for higher image quality. In such a case, the sensitivity is hardly lowered. However, since a polycarbonate resin having a mechanical strength lower than that of the polyarylate resin is used as the binder resin for the surface layer, it cannot be said that the durability is sufficient. On the other hand, when the polyarylate resin disclosed in Patent Document 2 is used for the surface layer of an electrophotographic photoreceptor, a highly durable electrophotographic photoreceptor can be obtained. However, a layer using a polyarylate resin has a relatively low transmittance with respect to light having a short wavelength, particularly light having a wavelength of 380 to 450 nm, and the sensitivity of the electrophotographic photosensitive member may be lowered. In particular, among polyarylate resins, when a polyarylate resin having a terephthalic acid (having a dicarboxylic acid group at the para position on the phenyl group) moiety in the charge transport layer is contained in the charge transporting layer, the light with respect to 380 to 450 nm is used. The transmittance tends to decrease. This decrease in transmittance with respect to light of 380 to 450 nm is considered to be caused by charge transfer between the terephthalic acid portion of the polyarylate resin and the charge transport material used in the photoreceptor, and has a relatively low unoccupied orbit. (LUMO orbit) is estimated to be prominent with terephthalic acid. Accordingly, in the current situation, a material having sufficient characteristics is not necessarily obtained from the viewpoint of achieving both high image quality and high durability of the electrophotographic photosensitive member.
Japanese Patent Laid-Open No. 10-20514 Japanese Patent Laid-Open No. 10-039521 Japanese Patent Laid-Open No. 9-73183 JP-A-9-319129 JP 2000-19765 A JP 2000-15326 A JP 2000-81715 A Japanese Patent Laid-Open No. 9-240051 JP 2000-105471 A

  The present invention has been made in view of the above-mentioned problems, has good durability when used repeatedly, and uses light having a short wavelength, particularly light having a wavelength of 380 to 450 nm as exposure light. It is an object of the present invention to provide an electrophotographic photosensitive member that hardly causes a decrease in sensitivity, a process cartridge having the same, and an electrophotographic apparatus.

  As a result of intensive studies, the inventors have found that the dispersibility of fluorine atom-containing resin fine particles is improved when a polyarylate resin having a specific structure is used, and the use of a dispersant can be made extremely small. It was. As a result, the inventors succeeded in improving the potential fluctuation in the repeated use of the electrophotographic photosensitive member having fluorine atom-containing resin fine particles, and reached the present invention. Furthermore, by using the polyarylate resin having this specific structure, electron transfer does not occur with the charge transport material, it has a high transmittance even for light of a short wavelength, and an image of 380 to 450 nm. Even when exposure light is used, a highly sensitive electrophotographic photoreceptor can be provided.

The electrophotographic photoreceptor according to the present invention is:
In an electrophotographic photosensitive member in which a charge generation layer and a charge transport layer are laminated in this order on a conductive support from the support side, the charge transport layer has the following formula (1):
(In formula (1), R ^{111 to} R ¹¹⁸ and R ^{211 to} R ²¹⁸ each independently represent hydrogen, an alkyl group having 1 to 4 carbon atoms, an aryl group, or an alkoxy group having 1 to 3 carbon atoms,
X is a single bond, an oxygen atom, a sulfur atom, or the following formula (2a)
(In Formula (2a), R ³¹¹ and R ³¹² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group, or an aryl group. In addition to these, R ³¹¹ and R ³¹² are R ³¹¹ and R ³¹² are combined to form a cycloalkylidene group or a fluorenylidene group.)
The bivalent group which has a structure shown by these is shown. )
A polyarylate resin having a structural unit represented by formula (1), a charge transport material, and fluorine atom-containing resin fine particles.

  A process cartridge and an electrophotographic apparatus according to the present invention include the electrophotographic photosensitive member.

  According to the present invention, durability is high and potential stability during repeated use is excellent. In addition, according to the present invention, even if light having a short wavelength, particularly light having a wavelength of 380 to 450 nm, is used as the exposure light, the sensitivity is hardly lowered.

  As described above, the electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are laminated in this order on a conductive support from the support side. 1. An electrophotographic photoreceptor comprising a polyarylate resin containing the structural unit represented by (1), a charge transport material, and fluorine atom-containing resin fine particles.

(In formula (1), R ^{111 to} R ¹¹⁸ and R ^{211 to} R ²¹⁸ each independently represent hydrogen, an alkyl group having 1 to 4 carbon atoms, an aryl group, or an alkoxy group having 1 to 3 carbon atoms,
X is a single bond, an oxygen atom, a sulfur atom, or the following formula (2a)
(In Formula (2a), R ³¹¹ and R ³¹² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group, or an aryl group. In addition to these, R ³¹¹ and R ³¹² are R ³¹¹ and R ³¹² are combined to form a cycloalkylidene group or a fluorenylidene group.)
The bivalent group which has a structure shown by these is shown. )

In the above equation ^(1), the alkyl group of R 111 ^{to R 118} and ^R 211 ^{to R 218,} a methyl group, an ethyl group, a propyl group and a butyl group. Examples of the aryl group include a phenyl group and a naphthyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Among these, R ^{111 to} R ¹¹⁸ and R ^{211 to} R ²¹⁸ are preferably a methyl group, an ethyl group, a methoxy group, an ethoxy group, and a phenyl group.

In the above formula (2a), examples of the alkyl group of R ³¹¹ and R ³¹² include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the fluorinated alkyl group include a trifluoromethyl group and a pentafluoroethyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Examples of the aryl group include a phenyl group and a naphthyl group. Among these, R ³¹¹ and R ³¹² are preferably methyl groups.

In addition, examples of the cycloalkylidene group formed by combining R ³¹¹ and R ³¹² in the above formula (2a) include a cyclopentylidene group, a cyclohexylidene group, a cycloheptylidene group, and the like. Among these, a cyclohexylidene group is preferable.

  Specific examples of the repeating structural unit represented by the above formula (1) are shown below.

  The electrophotographic photoreceptor of the present invention contains a polyarylate resin having a repeating structural formula represented by the above formula (1) in the charge transport layer and fluorine atom-containing resin fine particles. From the viewpoint of the dispersibility of the fluorine atom-containing resin fine particles and the resin strength, the structural unit represented by the above formula (1) is 50 mol% or more and 100 mol% or less in all the structural units in the polyarylate resin. Is preferred. Moreover, it is more preferable that it is 70 mol% or more and 100 mol% or less, and it is most preferable that it is 100%.

  Further, the polyarylate resin having the structural unit represented by the above formula (1) used for the charge transport layer of the electrophotographic photosensitive member of the present invention may have the structural unit represented by the above formula (1). It may be a homopolymer or a copolymer. In particular, in the case of a copolymer, the structural unit represented by the above formula (1) and the structural unit represented by the above formula (1) selected from the above formula (1), which is different from this structural unit, It may be a copolymer having Moreover, the copolymer which has a structural unit shown by the above-mentioned formula (1), and a structural unit which consists of another bivalent carboxylic acid and a bivalent organic residue may be sufficient. In the case of a copolymer, the polymerization form may be any polymerization form such as block copolymerization or random copolymerization, and is preferably a random copolymerization form.

  Further, in the present invention, the structural unit represented by the above formula (1), a structural unit selected from the above formula (1), which is different from this structural unit, or another divalent carboxylic acid and 2 The description that the copolymerization ratio in terms of molar ratio of the copolymerized polyarylate resin having a structural unit composed of a valent organic residue is A: B indicates that the dicarboxylic acid ester moiety represented by the above formula (1) is (1 -C), the bisphenol moiety (1-B), the structural unit represented by the above formula (1) different from the structural unit selected from the above formula (1), or other divalent carboxylic acid and divalent When the dicarboxylic acid ester moiety shown in the structural unit consisting of the organic residue is (3-C) and the bisphenol moiety is (3-B), the dicarboxylic acid ester moiety (1-C): (3 -C) is A: B and is bisphenol in terms of molar ratio. Nord site (1-B) :( 3-B) is A: it means that a B.

  Examples of the divalent carboxylic acid used in the structural unit composed of the other divalent carboxylic acid and divalent organic residue described above include aromatic divalent carboxylic acids, linear aliphatic divalent carboxylic acids, and cyclic fats. Group divalent carboxylic acids such as terephthalic acid. Examples of aromatic divalent carboxylic acids include isophthalic acid, diphenyldicarboxylic acid, and naphthalenedicarboxylic acid. Examples of the linear aliphatic divalent carboxylic acids include succinic acid, adipic acid, sebacic acid, and dodecanoic acid. Examples of the cycloaliphatic divalent carboxylic acids include cyclohexylene dicarboxylic acid. Of these, terephthalic acid and isophthalic acid are preferable. Examples of the divalent organic residue include bisphenols such as 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) and 2,2-bis (3-methyl-4-hydroxyphenyl) propane (bisphenol C), Biphenols such as 4,4′-hydroxybiphenyl are included. Hereinafter, structural examples of repeating structural units composed of these other divalent carboxylic acids and divalent organic residues are shown.

  As described above, the polyarylate resin having the structural unit represented by the above formula (1) used in the charge transport layer of the electrophotographic photosensitive member of the present invention has a weight average molecular weight of 80000 or more. Among the polyarylate resins having the structural unit represented by the above formula (1), those having a weight average molecular weight of less than 80000 have low mechanical strength and are insufficient for improving the durability of the electrophotographic photosensitive member. Furthermore, it is preferable that a weight average molecular weight is 90000 or more.

  On the other hand, when the molecular weight of the polyarylate resin having the structural unit represented by the above formula (1) is too large, the coating property of the coating liquid containing this may be deteriorated. The weight average molecular weight of the polyarylate resin having a structural unit is preferably 300,000 or less, more preferably 200000 or less.

  Fluorine atom-containing resin fine particles used in the charge transport layer of the electrophotographic photosensitive member of the present invention include tetrafluoroethylene resin, trifluorochloroethylene resin, tetrafluoroethylene hexafluoroethylenepropylene resin, and vinyl fluoride resin. And particles of vinylidene fluoride resin, ethylene difluoride dichloride resin, and copolymer resins thereof. Among these, tetrafluoroethylene resin (polytetrafluoroethylene) particles are particularly preferable.

  The particle diameter is preferably 0.05 to 0.50 μm, more preferably 0.10 to 0.40 μm in terms of volume average particle diameter.

  Various types of fluorine atom-containing resin particles such as homogenizers, line mixers, ultradispersers, homomixers, liquid collision type high-speed dispersers, and ultrasonic dispersers are used to uniformly contain fluorine atom-containing resin particles in the charge transport layer. It can disperse | distribute using mixing apparatuses, such as an emulsifier, a disperser, and a mixer.

  At this time, the diorganopolysiloxane resin represented by the formulas (11) and (12) is used as a dispersant in order to control the particle size to a preferable size, and the fluorine atom-containing resin fine particles and the binder resin are mixed. It is preferable to disperse in advance.

  The diorganopolysiloxane represented by the formulas (11) and (12) 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. The average molecular weight is 10,000 to 1,000,000.

In the above formulas (11) and (12), R ¹¹ and R ¹² each independently represent a substituted or unsubstituted monovalent hydrocarbon group. B ¹¹ represents a monovalent organic group having a perfluoroalkyl group. 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, or a substituted or unsubstituted siloxane chain. A monovalent group selected from the group consisting of a valent organic group and a monovalent organic group having 12 or more carbon atoms is shown.

  Moreover, the above-mentioned diorganopolysiloxane may further have a repeating structural unit γ represented by the following formula (13).

In 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).

E ¹¹ − (14)

In formulas (14) and (15), R ¹⁵ and R ¹⁶ each independently represent a substituted or unsubstituted monovalent hydrocarbon group. E ¹¹ and E ¹² each independently have a substituted or unsubstituted monovalent hydrocarbon group, a monovalent organic group having a perfluoroalkyl group, or 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 monovalent organic group having a substituted or unsubstituted siloxane chain, and a monovalent organic group having 12 or more carbon atoms. 1 represents a monovalent group selected from the group. However, ^{E 11} in formula (14) is bonded to Si of the repeating backbone of the structural units (-Si-O-) in having the diorganopolysiloxane, Si in the above equation (15) is diorgano Bonded with O in the main chain (-Si-O-) of the repeating structural unit of the polysiloxane.

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

The above-described monovalent organic group having a B ¹¹ perfluoroalkyl group is preferably a monovalent group having a structure represented by the following formula (2).

In the above formula (2), R ²¹ represents an alkylene group or an alkyleneoxyalkylene 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 above-mentioned alkyleneoxyalkylene group include an ethyleneoxyethylene group, an ethyleneoxypropylene group, and a propyleneoxypropylene group.

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

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

  Examples of the divalent hydrocarbon group include alkylene groups such as a methylene group, an ethylene group, and a propylene group, and preferably have 1 to 10 carbon atoms. 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 above-mentioned 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 (4).

In formula (4), R ⁴¹ and R ⁴² each independently represent a substituted or unsubstituted divalent hydrocarbon group. R ⁴³ represents a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon 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 above d is preferably 5 or more.

The above-mentioned 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 (5).

In the above formula (5), R ⁵¹ represents an alkylene group, an alkyleneoxy group, or an oxygen atom, and R ^{52 to} R ⁵⁶ are each independently a substituted or unsubstituted alkyl group, or a substituted or unsubstituted group. Represents an aryl group, and 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 above e is preferably 5 or more.

Examples of the above-mentioned 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. Is mentioned.

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

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

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

  It is preferable that the repeating structural unit which the above-mentioned diorganopolysiloxane has is only the repeating structural unit α represented by the formula (11) and the repeating structural unit β represented by the formula (12). Moreover, the repeating structural unit which the above-mentioned diorganopolysiloxane has is a repeating structural unit α represented by the formula (11), a repeating structural unit β represented by the formula (12), and a repeating structure represented by the formula (13). The unit γ is preferred only.

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

When the number of the 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 may be It may be the same group 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 may be It may be the same group 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. Either a monovalent organic group having a chain or a monovalent organic group having 12 or more carbon atoms. When there are a plurality of D ¹¹ , at least one D ¹¹ is preferably a monovalent organic group having a substituted or unsubstituted siloxane chain.

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 may be It may be the same group or two or more different groups.

The same applies to R ³² and R ^{33 in} the above formula (3), R ^{42 in} the above formula (4), and R ⁵² and R ^{53 in} the above formula (5).

Below, the specific example of the diorganopolysiloxane used for this invention is shown. However, it is not limited to these. Further, the following diorganopolysiloxanes (1-1) to (1-23) are all terminal groups I (E ¹¹ : methyl group) having the structure represented by the above formula (14) as terminal groups, terminal group ^II having a structure represented by the formula ^{(15) (E 12, R} 15, R 16: methyl) having a. In addition, among the structures shown in (1-1) to (1-23), any terminal substituents not particularly described are linear.

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

  The weight average molecular weight of the diorganopolysiloxane used in the present invention is preferably 10,000 to 200,000, more preferably 10,000 to 100,000, and still more preferably 20,000 to 40,000.

  The content of the diorganopolysiloxane in the electrophotographic photoreceptor of the present invention is preferably the minimum amount necessary for making the fluorine atom-containing resin fine particles have a desired dispersed particle size. The higher the content of the dispersant, the more likely to cause carrier traps and the potential fluctuations during repeated use are likely to occur. On the other hand, if the amount is too small, a sufficiently dispersed state cannot be obtained, and the effect of wear resistance of the fluorine atom-containing resin fine particles cannot be obtained. Usually, as disclosed in Patent Document 6, fluorine atom-containing resin fine particles A dispersant of 0.1 part by mass or more is required with respect to 100 parts by mass.

  However, in the case of the present invention, the dispersibility of the fluorine atom-containing resin fine particles is good when the ratio of the formula (1) is a polyarylate resin of 50% or more in the structure of the binder to be used. Moreover, even if the amount of the dispersant is less than 0.1 parts by mass with respect to 100 parts by mass of the fluorine atom-containing resin fine particles, good dispersion is possible. Furthermore, if the polyarylate resin has a structure of only formula (1), a good dispersion state can be obtained without using a dispersant.

  In addition, in order to obtain a better dispersion state when pre-dispersed with diorganopolysiloxane, fluorine atom-containing resin fine particles, and a binder resin containing at least the polyarylate resin represented by the formula (1), The mass part of the binder resin is preferably equal to or greater than the mass part of the fine particles, and more preferably 1.5 times the mass part.

  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 it is less than 0.5 parts by mass, the effect of wear resistance is small. When the amount exceeds 30 parts by mass, the light transmittance is deteriorated and scattering occurs, which adversely affects the electrophotographic characteristics.

  The polyarylate resin having the structural unit represented by the formula (1) used in the charge transport layer of the electrophotographic photosensitive member of the present invention can be synthesized by a transesterification method between a dicarboxylic acid ester and a compound having a hydroxyl group. is there. It can also be synthesized by a polymerization reaction between a divalent acid halide such as dicarboxylic acid halide and a compound having a hydroxyl group such as bisphenol. When producing a polyarylate resin having a weight average molecular weight in the above range, it is preferably synthesized by the latter synthesis method.

(Synthesis Example 1)
Hereinafter, as a synthesis example, a method for synthesizing a polyarylate resin in which 100% of all structural units in the polyarylate resin is a repeating structural unit represented by the above formula (B1-2) in terms of molar ratio is shown.

  Diphenyl ether dicarboxylic acid chloride having a structure represented by the following formula (1-2-1) was dissolved in dichloromethane to prepare an acid chloride solution.

  In addition to the acid chloride solution, 2,2-bis (3-methyl-4-hydroxyphenyl) propane having a structure represented by the following formula (1-2-2) is dissolved in a 10% aqueous sodium hydroxide solution. I let you. To this, tributylbenzylammonium chloride was added as a polymerization catalyst and stirred to prepare a 2,2-bis (3-methyl-4-hydroxyphenyl) propane solution.

  Next, the acid chloride solution was added to the 2,2-bis (3-methyl-4-hydroxyphenyl) propane solution with stirring to initiate polymerization. The polymerization was carried out for 3 hours while maintaining the reaction temperature at 25 ° C. or lower and stirring.

  Thereafter, the polymerization reaction was terminated by the addition of acetic acid, and washing with water was repeated until the aqueous phase became neutral.

  After washing, the solution was dropped into methanol with stirring to precipitate a polymer, and this polymer was vacuum-dried to obtain a polyarylate resin which is a structural unit represented by the above formula (B1-2). The polystyrene-reduced weight average molecular weight of the polyarylate resin (hereinafter also referred to as weight average molecular weight (Mw)) was 130,000.

(Synthesis Example 2)
Hereinafter, as a synthesis example, in all the structural units in the polyarylate resin, 70% in terms of molar ratio is the structural unit represented by the above formula (B1-2), and 30% is the above formula (B3-9). The synthesis method of the polyarylate resin which is a structural unit shown by this is shown.

  Diphenyl ether dicarboxylic acid chloride having a structure represented by the following formula (1-2-1) and terephthalic acid chloride represented by the following formula (3-9-1) were mixed at a molar ratio of 7: 3. This was dissolved in dichloromethane to prepare a mixed solution of diphenyl ether dicarboxylic acid chloride and terephthalic acid chloride (hereinafter referred to as an acid chloride mixed solution).

  In addition to the acid chloride mixed solution, 2,2-bis (3-methyl-4-hydroxyphenyl) propane having a structure represented by the following formula (1-2-2) and the following formula (3-9) The tetramethylbiphenol represented by -2) was mixed at a molar ratio of 7: 3.

  This was dissolved in a 10% aqueous sodium hydroxide solution, and tributylbenzylammonium chloride as a polymerization catalyst was added thereto and stirred, and 2,2-bis (3-methyl-4-hydroxyphenyl) propane, tetramethylbiphenol and A mixed solution was prepared.

  Next, the acid chloride mixed solution was added to the mixed solution of 2,2-bis (3-methyl-4-hydroxyphenyl) propane and tetramethylbiphenol with stirring to initiate polymerization. The polymerization was carried out for 3 hours while maintaining the reaction temperature at 25 ° C. or lower and stirring.

  Thereafter, acetic acid was added to terminate the polymerization reaction, and washing with water was repeated until the aqueous phase became neutral.

  After washing, the solution is dropped into methanol with stirring to precipitate a polymer, and this polymer is vacuum-dried. In all the structural units in the polyarylate resin, 70% is converted into the above formula (B1-2). ), And a polyarylate resin in which 30% is a structural unit represented by the above formula (B3-9) was obtained. The weight average molecular weight Mw in terms of polystyrene of this polyarylate resin was 130,000.

  In the present invention, the polystyrene-converted weight average molecular weight of the resin was measured as follows according to a conventional method.

  That is, the measurement target resin is put in tetrahydrofuran and allowed to stand for several hours, and then mixed well with the measurement target resin and tetrahydrofuran while shaking (mixed until the measurement target resin is no longer united), and then allowed to stand for 12 hours or more. .

  Then, what passed the sample processing filter Myshoori disk H-25-5 by Tosoh Corporation was made into the sample for gel permeation chromatography (GPC).

  Next, the column is stabilized in a heat chamber at 40 ° C., tetrahydrofuran as a solvent is flowed to the column at this temperature at a flow rate of 1 mL / min, 10 μL of a GPC sample is injected, and the weight average molecular weight of the measurement target resin Was measured. A column TSKgel Super HM-M manufactured by Tosoh Corporation was used as the column.

  In measuring the weight average molecular weight of the measurement target resin, the molecular weight distribution of the measurement target resin was calculated from the relationship between the logarithmic value of the calibration curve prepared from several monodisperse polystyrene standard samples and the number of counts. Ten standard disperse polystyrenes (manufactured by Aldrich) having a molecular weight of 800 to 2,000,000 were used as standard polystyrene samples for preparing a calibration curve. An RI (refractive index) detector was used as the detector.

The confirmation of the copolymerization ratio of the resin that is copolymerized with the resin of the present invention is performed by a conversion method based on the peak area ratio of hydrogen constituting the resin by ¹ H-NMR measurement of the resin, which is a general technique. The copolymerization ratio was confirmed.

  Next, the configuration of the electrophotographic photosensitive member of the present invention will be described.

  As described above, the electrophotographic photosensitive member of the present invention includes a support, a charge generation layer containing a charge generation material provided on the support, and a charge transport layer containing a charge transport material. This is a (functional separation type) photoreceptor. That is, the electrophotographic photoreceptor according to the present invention has a normal type photosensitive layer in which a charge generation layer and a charge transport layer are laminated in this order from the support side.

  As a support body, what is necessary is just to have electroconductivity (electroconductive support body), For example, metal (alloy-made) support bodies, such as aluminum, aluminum alloy, and stainless steel, can be used. Moreover, the said metal support body and plastic support body which have a layer in which aluminum, an aluminum alloy, an indium oxide tin oxide alloy etc. were formed into a film by vacuum deposition can also be used. In addition, a support in which conductive particles such as carbon black, tin oxide particles, titanium oxide particles, and silver particles are impregnated into plastic or paper together with an appropriate binder resin, or a plastic support having a conductive binder resin, etc. Can also be used. In addition, examples of the shape of the support include a cylindrical shape and a belt shape, and a cylindrical shape is preferable.

  The surface of the support may be subjected to cutting treatment, roughening treatment, alumite treatment, etc. for the purpose of preventing interference fringes due to scattering of laser light or the like.

  Between the support and the photosensitive layer (charge generation layer, charge transport layer) or an intermediate layer described later, a conductive layer for the purpose of preventing interference fringes due to scattering of laser light or the like and covering the scratches on the support May be provided.

  The conductive layer can be formed by dispersing conductive particles such as carbon black, metal particles, and metal oxide particles in a binder resin.

  The thickness of the conductive layer is preferably 1 to 40 μm, and more preferably 2 to 20 μm.

  Further, an intermediate layer having a barrier function or an adhesive function may be provided between the support or the conductive layer and the photosensitive layer (charge generation layer, charge transport layer). The intermediate layer is formed for the purpose of improving the adhesion of the photosensitive layer, improving the coating property, improving the charge injection property from the support, and protecting the photosensitive layer from electrical breakdown.

  The intermediate layer is acrylic resin, allyl resin, alkyd resin, ethyl cellulose resin, ethylene-acrylic acid copolymer, epoxy resin, casein resin, silicone resin, gelatin resin, polyamide, phenol resin, butyral resin, polyacrylate resin, polyacetal resin, polyamide Imide resin, polyamide resin, polyallyl ether resin, polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polysulfone resin, polyvinyl alcohol resin, polybutadiene resin, polypropylene resin, urea resin, etc. It can be formed using a material such as aluminum.

  The thickness of the intermediate layer is preferably 0.05 to 5 μm, and more preferably 0.3 to 1 μm.

  Examples of the charge generating material used in the electrophotographic photoreceptor of the present invention include azo pigments such as monoazo, disazo, and trisazo, phthalocyanine pigments such as metal phthalocyanine and nonmetal phthalocyanine, indigo pigments such as indigo and thioindigo, Perylene pigments such as perylene anhydride, perylene imide, polycyclic quinone pigments such as anthraquinone, pyrenequinone, dibenzpyrenequinone, squarylium dyes, pyrylium salts and thiapyrylium salts, triphenylmethane dyes, selenium, Inorganic substances such as selenium-tellurium and amorphous silicon, quinacridone pigments, azurenium salt pigments, cyanine dyes such as quinocyanine, anthanthrone pigments, pyranthrone pigments, xanthene dyes, quinoneimine dyes, styryl Motoya, and cadmium sulfide, and zinc oxide. These charge generation materials may be used alone or in combination of two or more.

  When the photosensitive layer is a laminated photosensitive layer and the charge generation layer is not a surface layer of an electrophotographic photosensitive member, examples of the binder resin used for the charge generation layer include acrylic resins, allyl resins, and alkyd resins. , Epoxy resin, diallyl phthalate resin, silicone resin, styrene-butadiene copolymer, polyamide, phenol resin, butyral resin, benzal resin, polyacrylate resin, polyacetal resin, polyamideimide resin, polyamide resin, polyallyl ether resin, polyarylate resin, Polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polysulfone resin, polyvinyl acetal resin, polybutadiene resin, polypropylene resin, methacrylic resin, urea resin Vinyl chloride - vinyl acetate copolymer, vinyl acetate resins, and vinyl chloride resins. In particular, a butyral resin is preferable. These may be used alone or in combination as a mixture or copolymer.

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

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

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

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

  Examples of the charge transport material used in the electrophotographic photoreceptor of the present invention include triarylamine compounds, hydrazone compounds, styryl compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds. These charge transport materials may be used alone or in combination of two or more.

  In the charge transport layer, at least a polyarylate resin having a structural unit represented by the above formula (1) is used as a binder resin. Other resins exemplified below can be used in combination as long as the effects of the present invention are not impaired. In that case, the ratio of the polyarylate resin represented by the above formula (1) in the charge transport layer is preferably 50% by mass or more based on the total mass of the binder resin contained in the charge transport layer. Furthermore, it is more preferable that it is 70 weight% or more. Examples of resins that can be used in combination include acrylic resins, acrylonitrile resins, allyl resins, alkyd resins, epoxy resins, silicone resins, polyamides, phenol resins, phenoxy resins, butyral resins, polyacrylamide resins, polyacetal resins, polyamideimide resins, polyamides. Resin, polyallyl ether resin, polyarylate resin, polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polysulfone resin, polyvinyl butyral resin, polyphenylene oxide resin, polybutadiene resin, polypropylene resin, methacrylic resin, urea Resin, vinyl chloride resin, vinyl acetate resin, etc. are mentioned. In particular, polyarylate resin, polycarbonate resin and the like are preferable. These may be used alone or in combination as a mixture or copolymer.

  The charge transport layer can be formed by applying a charge transport layer coating solution obtained by dissolving a charge transport material and a binder resin in a solvent and drying it. The ratio between the charge transport material and the binder resin is preferably in the range of 2: 1 to 1: 3 (mass ratio).

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

  The thickness of the charge transport layer is preferably 5 to 40 μm, and more preferably 10 to 35 μm.

  In addition, an antioxidant, an ultraviolet absorber, a plasticizer, and the like can be added to the charge transport layer as necessary.

  FIG. 1 shows an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

  In FIG. 1, reference numeral 1 denotes a cylindrical electrophotographic photosensitive member, which is rotationally driven in a direction of an arrow about a shaft 2 at a predetermined peripheral speed.

  The surface of the electrophotographic photosensitive member 1 that is driven to rotate is uniformly charged to a predetermined positive or negative potential by a charging unit (primary charging unit: charging roller or the like) 3. Next, exposure light (image exposure light) 4 output from exposure means (not shown) such as slit exposure or laser beam scanning exposure is received. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the surface of the electrophotographic photosensitive member 1.

  The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed with toner contained in the developer of the developing means 5 to become a toner image. Next, the toner image formed and supported on the surface of the electrophotographic photoreceptor 1 is transferred from the transfer material supply means (not shown) to the electrophotographic photoreceptor 1 by a transfer bias from a transfer means (transfer roller or the like) 6. The image is sequentially transferred to a transfer material (paper or the like) P fed between the means 6 (contact portion) in synchronization with the rotation of the electrophotographic photosensitive member 1.

  The transfer material P that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member 1 and introduced into the fixing means 8 to receive the image fixing, and is printed out as an image formed product (print, copy). Is done.

  The surface of the electrophotographic photosensitive member 1 after the transfer of the toner image is cleaned by a cleaning means (cleaning blade or the like) 7 to remove the developer (toner) remaining after the transfer, and further a pre-exposure means (not shown). After being subjected to a charge removal process by pre-exposure light (not shown), the image is repeatedly used for image formation. As shown in FIG. 1, when the charging unit 3 is a contact charging unit using a charging roller or the like, pre-exposure is not necessarily required.

  Among the above-described components such as the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5, the transfer unit 6, and the cleaning unit 7, a plurality of components may be housed in a container and integrally combined as a process cartridge. Good. The process cartridge may be configured to be detachable from the main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. In FIG. 2, the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5 and the cleaning unit 7 are integrally supported to form a cartridge, and the electrophotographic apparatus is used by using a guide unit 10 such as a rail of the electrophotographic apparatus main body. The process cartridge 9 is detachable from the main body.

  FIG. 2 shows an example of a schematic configuration of a full-color electrophotographic apparatus (in-line system) provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

  In FIG. 2, 1Y, 1M, 1C, and 1K are cylindrical electrophotographic photosensitive members (first to fourth color electrophotographic photosensitive members), and the directions of the arrows are about axes 2Y, 2M, 2C, and 2K, respectively. Are rotated at a predetermined peripheral speed.

  The surface of the rotationally driven first color electrophotographic photoreceptor 1Y is uniformly charged to a predetermined positive or negative potential by a first color charging means (primary charging means: charging roller or the like) 3Y. Next, exposure light (image exposure light) 4Y output from exposure means (not shown) such as slit exposure or laser beam scanning exposure is received. The exposure light 4Y is exposure light corresponding to a first color component image (for example, a yellow component image) of a target color image. Thus, a first color component electrostatic latent image (yellow component electrostatic latent image) corresponding to the first color component image of the target color image is sequentially formed on the surface of the first color electrophotographic photoreceptor 1Y.

  The transfer material conveyance member (transfer material conveyance belt) 14 stretched by the tension roller 12 has substantially the same peripheral speed as the first to fourth color electrophotographic photoreceptors 1Y, 1M, 1C, 1K in the direction of the arrow ( For example, it is rotationally driven at 97 to 103% of the peripheral speeds of the first to fourth color electrophotographic photoreceptors 1Y, 1M, 1C, and 1K. Further, the transfer material (paper or the like) P fed from the transfer material supply means 17 is electrostatically carried (adsorbed) on the transfer material transport member 14, and the electrophotographic photoreceptor 1Y for the first to fourth colors. 1M, 1C, 1K and the transfer material conveyance member (contact portion) are sequentially conveyed.

  The first color component electrostatic latent image formed on the surface of the first color electrophotographic photoreceptor 1Y is developed with the toner of the first color developing means 5Y to become a first color toner image (yellow toner image). . Next, the first color toner image formed and supported on the surface of the first color electrophotographic photosensitive member 1Y is transferred to the first color electrophotographic image by the transfer bias from the first color transfer means (transfer roller or the like) 6Y. The image is sequentially transferred onto the transfer material P carried on the transfer material conveying member 14 that passes between the photoreceptor 1Y and the first color transfer means 6Y.

  The surface of the first color electrophotographic photosensitive member 1Y after the transfer of the first color toner image is cleaned by removing the transfer residual toner by the first color cleaning means (cleaning blade or the like) 7Y, and then repeatedly. Used for first color toner image formation.

  First color electrophotographic photoreceptor 1Y, first color charging means 3Y, first color exposure means for outputting exposure light 4Y corresponding to the first color component image, first color developing means 5Y and first color. The transfer unit 6Y is collectively referred to as a first color image forming unit.

  Hereinafter, the respective colors are the same as in the case of the first color described above. That is, the second color image forming unit includes a second color electrophotographic photosensitive member 1M, a second color charging unit 3M, a second color exposure unit that outputs exposure light 4M corresponding to the second color component image, It has second color developing means 5M and second color transfer means 6M. The third color image forming unit includes a third color electrophotographic photosensitive member 1C, a third color charging unit 3C, a third color exposure unit that outputs exposure light 4C corresponding to the third color component image, A third color developing unit 5C and a third color transfer unit 6C are provided. Further, the fourth color image forming unit includes a first color electrophotographic photoreceptor 1K, a fourth color charging unit 3K, a fourth color exposure unit that outputs exposure light 4K corresponding to the fourth color component image, It has fourth color developing means 5K and fourth color transfer means 6K. The operations of the second color image forming unit, the third color image forming unit, and the fourth color image forming unit are the same as the operations of the first color image forming unit. That is, the second color toner image (magenta toner image), the third color toner image (cyan toner image), and the fourth color are transferred to the transfer material P that is carried on the transfer material conveyance member 14 and onto which the first color toner image is transferred. Toner images (black toner images) are sequentially transferred. In this way, a synthetic toner image corresponding to the target color image is formed on the transfer material P carried on the transfer material conveying member 14.

  The transfer material P on which the synthetic toner image is formed is separated from the surface of the transfer material conveying member 14 and is introduced into the fixing unit 8 to be subjected to image fixing, thereby being printed out of the apparatus as a full color image formed product (print, copy). Be out.

  Further, the first to fourth color electrophotographic photoconductors 1Y, 1M, 1C and 1K after the transfer residual toner is removed by the first to fourth color cleaning means 7Y, 7M, 7C and 7K You may neutralize with the pre-exposure light from an exposure means. As shown in FIG. 2, when the first to fourth color charging units 3Y, 3M, 3C, and 3K are contact charging units using a charging roller, pre-exposure is not necessarily required.

  A plurality of components such as the above-described electrophotographic photosensitive member, charging unit, developing unit, transfer unit, and cleaning unit may be housed in a container and integrally coupled as a process cartridge. The process cartridge may be configured to be detachable from the main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. In FIG. 2, for each image forming unit, an electrophotographic photosensitive member, a charging unit, a developing unit, and a cleaning unit are integrally supported to form a cartridge, and a guide unit (not shown) such as a rail of an electrophotographic apparatus main body. The process cartridges 9Y, 9M, 9C, and 9K are detachable from the main body of the electrophotographic apparatus.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to these. In the examples, “part” means “part by mass”. “Mw” means “polystyrene equivalent weight average molecular weight”.

(Example 1-1)
An aluminum cylinder having a diameter of 30 mm and a length of 357 mm was used as a support.

Next, the coating liquid for conductive layers was prepared using the following components.
SnO ₂ Coated barium sulfate (conductive particles) 10 parts Titanium oxide (resistance resistance pigment) 2 parts Phenol resin (binder resin) 6 parts Silicone oil (leveling agent) 0.001 part Methanol 4 parts / Methoxypropanol 16 parts Mixed solvent

  This conductive layer coating solution was dip-coated on a support and thermally cured at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm.

  Next, 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon were dissolved in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol to prepare an intermediate layer coating solution.

  This intermediate layer coating solution was dip coated on the conductive layer and dried at 100 ° C. for 10 minutes to form an intermediate layer having a thickness of 0.7 μm.

  Next, strong peaks at 7.5 °, 9.9 °, 16.3 °, 18.6 °, 25.1 ° and 28.3 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction 10 parts of a crystalline form of hydroxygallium phthalocyanine (charge generating substance) having a hydrogen content of 250 parts of cyclohexanone and 5 parts of polyvinyl butyral resin (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) are dissolved in the solution. Dispersion was carried out for 1 hour in a 23 ± 3 ° C. atmosphere using a sand mill using glass beads having a diameter of 1 mm. After dispersion, 250 parts of ethyl acetate was added to prepare a coating solution for charge generation layer.

  This charge generation layer coating solution was dip coated on the intermediate layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.26 μm.

  Next, a coating for the charge transport layer was prepared in order to form the charge transport layer.

First, 10 parts of polyarylate resin (Mw = 80000) having a repeating unit represented by the above formula (B1-1) as polyarylate resin was dissolved in 100 parts of monochlorobenzene. To this, 5 parts of polytetrafluoroethylene resin fine particles (Lublon L-2: manufactured by Daikin Industries, Ltd.) and 0.004 part of diorganopolysiloxane represented by the above formula (1-4) were 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 used 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.). As a result, the volume average particle diameter was 0.18 μm.

  Next, the ratio of CTM-1 / CTM-2 / polyarylate resin / polytetrafluoroethylene resin fine particles / diorganopolysiloxane / solvent represented by the following formula is 9/1/10 / 2.5 / in the final ratio. The coating material was prepared so that it might become 0.002 / 80.

  As the polytetrafluoroethylene resin fine particles, the fluorine atom-containing resin fine particle dispersion previously dispersed was used. The solvent was prepared so that the final ratio was monochlorobenzene / dimethoxymethane = 7/3. This paint was applied onto the previous charge transport layer by a dip coating method and dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 30 μm.

  Next, evaluation will be described.

  As an evaluation machine, a Canon Co., Ltd. copy machine GP-40 was remodeled so that the light quantity of the laser light source could be adjusted. The process of this apparatus is the following (1) to (3).

(1) The process of charging the photoconductor by applying DC and AC voltage from a charging member placed in contact with the electrophotographic photoconductor (2) Digital exposure with 780 nm laser light (3) Reversal development The process speed of this machine Is 210 mm / sec, and the copying speed is A4 horizontal 40 sheets / min. A photoconductor for evaluation was mounted and the initial potential was first measured. The surface potential of the electrophotographic photosensitive member was measured at the developing device position by exchanging the jig and the developing device fixed so that the potential measuring probe was positioned at a position 180 mm from the upper end of the electrophotographic photosensitive member. The dark portion potential was set to Vd = −700V, and the light amount was adjusted so that the bright portion potential was Vl = −200V. In addition, an intermittent mode (10 seconds / copy interval) in which the paper stops once every time A4 size plain paper is copied. In this mode, an image with a printing ratio of 4% was copied on 30,000 sheets in an ambient environment of 23 ° C./55% RH, and the potential was measured.

  Thereafter, a character image and a halftone image having a reflection density D = 0.4 (Macoth reflection density meter RD914, zero adjust value = 0.06, calibration adjustment value = 1.73) were copied. For the halftone image, the reflection density was measured at any 20 points in the image, and the difference between the maximum density and the minimum density was defined as the image density unevenness. The surface potential was measured after the initial and 30,000 repetitive copying, and the difference in light portion potential (ΔVl) was examined. Note that ΔVl is (absolute value of light portion potential after 30,000 sheets) − (absolute value of initial light portion potential). The amount of wear was determined from the difference between the film thickness before durability and the film thickness after durability. The film thickness at that time was measured with a film thickness measuring device, Fisher MMS Eddy Current Method Probe EAW3.3, manufactured by Fischer Corporation.

(Example 1-2)
In Example 1-1, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1-1 except that diorganopolysiloxane was not used.

(Examples 1-3 to 1-28, Comparative examples 1-1 to 1-4)
In Example 1-1, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1-1 except that the binder resin of the charge transport layer was changed as shown in Table 35 and Table 36. The results are shown in Table 37.

(Example 1-29)
In Example 1-1, an electrophotographic photosensitive member was produced in the same manner as in Example 1-1 except that diorganopolysiloxane (1-1) was used instead of diorganopolysiloxane (1-4). And evaluated. The results are shown in Table 37.

  In Tables 35 and 36, (C-1) is a resin having the structure shown below.

(Example 1-30)
In Example 1-1, CTM-3 / CTM-1 / polyarylate resin / polytetrafluoroethylene resin fine particles / diorganopolysiloxane / in place of CTM-1 / CTM-2 as the charge transport material of the charge transport layer An electrophotographic photosensitive member was prepared in the same manner as in Example 1-1 except that the coating material was prepared so that the solvent ratio was 6/2/10 / 2.5 / 0.002 / 80 in the final ratio. ,evaluated. The results are shown in Table 37.

(Comparative Example 1-5)
In Example 1-1, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1-1 except that the polytetrafluoroethylene resin fine particles were not used. The results are shown in Table 37.

(Comparative Example 1-6)
In Example 1-1, an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1-1 except that the polytetrafluoroethylene resin fine particles and the diorganopolysiloxane were not used. The results are shown in Table 37.

(Reference Example 1-1)
In Comparative Example 1-3, the ratio of CTM-1 / CTM-2 / polyarylate resin / polytetrafluoroethylene resin fine particles / diorganopolysiloxane / solvent was 9/1/10 / 2.5 / 0 in the final ratio. An electrophotographic photosensitive member was prepared and evaluated in the same manner as Comparative Example 1-3 except that the coating material was prepared so as to be .25 / 80. The results are shown in Table 37.

  As shown in Table 37, in the example, the wear amount of the photoreceptor was small and a good image was obtained. In Comparative Examples 1-1 to 1-4, since a resin binder other than the present invention was used, a sufficient dispersion state could not be obtained with the same amount of diorganopolysiloxane as in the Examples. Further, in Comparative Examples 1-1 to 1-4, not only the effect of improving the wear resistance of the fluorine atom-containing resin fine particles is not obtained, but also the exposure light is scattered in the charge transport layer, and particularly, a halftone image. In this case, the image becomes a rough image in which uneven density (unevenness) is emphasized.

  Even in the system using the resin used in the present invention of Comparative Examples 1-1 to 1-4, as in Reference Example 1-1, if the amount of diorganopolysiloxane is increased, a good dispersion state is obtained and good. Can be obtained. However, the rise of the bright portion potential due to durability increases, and the characteristics of the photoreceptor of the present invention are also inferior.

  In other words, since the electrophotographic photosensitive member of the present invention has a particularly good compatibility between the fluorine atom-containing resin fine particles and the binder, a good dispersion can be obtained with a small amount of diorganopolysiloxane as compared with a combination with other resins. It can be said that the function of the fluorine atom-containing resin fine particles can be expressed more effectively because the bright portion potential does not increase due to durability.

  Further, in Comparative Examples 1-5 and 1-6, since no fluorine atom-containing resin fine particles were added, a good image was obtained, but the wear amount was large compared to the Examples, and in terms of durability. The photoconductor was inferior to the photoconductor of Example.

(Example 2-1)
An aluminum plate was used as a support.

  Next, 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon were dissolved in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol to prepare an intermediate layer coating solution.

  This intermediate layer coating solution was applied onto a support with a Meyer bar and dried at 100 ° C. for 10 minutes to form an intermediate layer having a thickness of 0.7 μm.

  Next, 20 parts of an azo pigment (charge generation material) having a structure represented by the following formula (CGM-1) and 10 parts of a butyral resin (degree of butyralization 65 mol%) were added to 400 parts of tetrahydrofuran. This was dispersed in a sand mill apparatus using glass beads having a diameter of 1 mm for 20 hours in an atmosphere of 23 ± 3 ° C. to prepare a charge generation layer coating solution.

  This charge generation layer coating solution was applied onto the intermediate layer with a Meyer bar and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.4 μm.

  Next, a coating for the charge transport layer was prepared in order to form the charge transport layer.

First, 10 parts of polyarylate resin (Mw = 70000) having a repeating unit represented by the above formula (B1-1) as polyarylate resin was dissolved in 100 parts of monochlorobenzene. To this, 5 parts of polytetrafluoroethylene resin fine particles (Lublon L-2: manufactured by Daikin Industries, Ltd.) and 0.004 part of diorganopolysiloxane represented by the above formula (1-4) were 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-containing resin fine particles are used 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.). Measured. As a result, the volume average particle diameter was 0.18 μm.

  Next, the ratio of CTM-4 / polyarylate resin / polytetrafluoroethylene resin fine particles / diorganopolysiloxane / solvent represented by the following formula is 8/10 / 2.5 / 0.002 / 80 in the final ratio. A paint was prepared as follows.

  As the polytetrafluoroethylene resin fine particles, the fluorine atom-containing resin fine particle dispersion previously dispersed was used. The solvent was prepared so that the final ratio was monochlorobenzene / dimethoxymethane = 7/3. This paint was applied onto the previous charge transport layer by a dip coating method and dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 28 μm.

  Next, evaluation will be described.

  As an evaluation apparatus, an electrostatic copying paper test apparatus EPA-8100 manufactured by Kawaguchi Electric Co., Ltd. was used.

The electrophotographic photosensitive member was charged with a corona charger so that the surface potential was −600 V (dark portion potential). Then, LED at a wavelength of 400 nm, 430 nm, irradiation with light of 450nm and (exposure), the surface potential was measured the amount of light required to decay to -300 V (light potential), half decay exposure sensitivity _{(E 1 / 2} ) was calculated at each wavelength.

The results are shown in Table 39. In Table 39, the sensitivity to light having a wavelength of 400 nm is E _1/2 (400), the sensitivity to light having a wavelength of 430 nm is E _1/2 (430), and the sensitivity to light having a wavelength of 450 nm is E _1/2 ( 450).

(Examples 2-2 to 2-27, Comparative Examples 2-1 to 2-4)
In Example 2-1, an electrophotographic photosensitive member in which the charge transport layer is a surface layer was obtained in the same manner as in Example 2-1, except that the binder resin for the charge transport layer was as shown in Table 38 and Table 39. Prepared and evaluated. The results are shown in Table 40.

  In Table 38, (C-1) is a resin having the structure shown below.

  From the comparison between Examples and Comparative Examples, even when the resin of the structural unit of the present invention is used, the characteristics are good when image exposure in the short wavelength region is used, and the photoreceptor of the present invention has a short wavelength region. It is shown that it is suitable for an electrophotographic photoreceptor using image exposure. In particular, an electrophotographic photosensitive member containing a conventional resin having a terephthalic acid structure in the resin structure used in the charge transport layer by comparing the examples with Comparative Examples 2-1 and 2-3 or Comparative Example 2-4; In the comparison, it was shown that the electrophotographic photosensitive member of the present invention has remarkably improved characteristics.

FIG. 2 is a diagram illustrating an example of a contact charging type process cartridge and an electrophotographic apparatus. 1 is a diagram illustrating an example of a full-color contact charging type electrophotographic apparatus. FIG. The process cartridge shown in FIG. 1 is a system in which yellow, magenta, cyan, and black are arranged in the vertical order from the bottom in a tiedem manner.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Axis 3 Charging means 4 Exposure light 5 Developing means 6 Transfer means 7 Cleaning means 8 Fixing means 9 Process cartridge 10 Guide means 17 Transfer material supply means P Transfer material 1Y First color electrophotographic photoreceptor 1M 1st 2-color electrophotographic photoreceptor 1C third-color electrophotographic photoreceptor 1K first-color electrophotographic photoreceptor 2Y axis 2M axis 2C axis 2K axis 3Y first color charging means 3M second color charging means 3C third Color charging means 3K Fourth color charging means 4Y Exposure light 4M Exposure light 4C Exposure light 4K Exposure light 5Y First color development means 5M Second color development means 5C Third color development means 5K Fourth color development Means 6Y First color transfer means 6M Second color transfer means 6C Third color transfer means 6K Fourth color transfer means 7Y First color cleaning means 7M Second color cleaning means 7C For 3-color cleaning device 7K fourth color cleaning means 9Y process cartridge 9M process cartridge 9C process cartridge 9K process cartridge 12 tension roller 14 the transfer material transport member

Claims (10)

In an electrophotographic photosensitive member in which a charge generation layer and a charge transport layer are laminated in this order on a conductive support from the support side, the charge transport layer has the following formula (1):
(In formula (1), R ^{111 to} R ¹¹⁸ and R ^{211 to} R ²¹⁸ each independently represent hydrogen, an alkyl group having 1 to 4 carbon atoms, an aryl group, or an alkoxy group having 1 to 3 carbon atoms,
X is a single bond, an oxygen atom, a sulfur atom, or the following formula (2a)
(In Formula (2a), R ³¹¹ and R ³¹² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group, or an aryl group. In addition to these, R ³¹¹ and R ³¹² are R ³¹¹ and R ³¹² are combined to form a cycloalkylidene group or a fluorenylidene group.)
The bivalent group which has a structure shown by these is shown. )
An electrophotographic photosensitive member comprising a polyarylate resin having a structural unit represented by the formula: a charge transporting material, and fluorine atom-containing resin fine particles.   The electrophotographic photosensitive member according to claim 1, wherein the polyarylate resin has a weight average molecular weight (Mw) of 80000 to 300000. The electrophotographic photosensitive member according to claim 1, wherein R ²¹¹ and R ²¹⁶ are methyl groups.   The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the structural unit is contained in an amount of 70 mol% to 100 mol% in all the structural units of the polyarylate resin. The charge transport layer includes a repeating structural unit α represented by the following formula (11) and a repeating structural unit β represented by the following formula (12).
(In Formula (11) and Formula (12), R ¹¹ and R ¹² each independently represent a substituted or unsubstituted monovalent hydrocarbon group,
B ¹¹ represents a monovalent organic group having a perfluoroalkyl group,
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, or a substituted or unsubstituted siloxane chain. A monovalent group selected from the group consisting of a valent organic group and a monovalent organic group having 12 or more carbon atoms is shown. )
5. The electrophotographic photoreceptor according to claim 1, comprising a diorganopolysiloxane having a weight average molecular weight of 10,000 to 200,000. The diorganopolysiloxane has the following formula (13):
(In formula (13), R ¹³ and R ¹⁴ each independently represents a substituted or unsubstituted monovalent hydrocarbon group.)
The electrophotographic photosensitive member according to claim 5, further comprising a repeating structural unit γ represented by:   An electrophotographic photosensitive member according to any one of claims 1 to 6 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 the electrophotographic apparatus main body is supported. A process cartridge that is detachable.   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.   The electrophotographic apparatus according to claim 8, wherein the exposure unit is a unit that irradiates the electrophotographic photosensitive member with exposure light having a wavelength of 380 nm to 450 nm.   The electrophotographic apparatus according to claim 9, wherein the exposure unit includes a laser having an oscillation wavelength of 380 nm to 450 nm.