JP4847251B2 - Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus - Google Patents

Description

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

  Photoconductive materials (charge generation 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. Therefore, organic photoconductive substances have been actively developed from the viewpoint of pollution-free, high productivity, and ease of material design.

  An electrophotographic photosensitive member (organic electrophotographic photosensitive member) using an organic photoconductive substance is obtained by applying a coating liquid obtained by dissolving and dispersing an organic photoconductive substance or a binder resin in a solvent on a support, Those having a photosensitive layer formed by drying this are usually used. The layer structure of the photosensitive layer is generally a laminate type (normal layer type) in which a charge generation layer and a charge transport layer are laminated in this order from the support side.

  An electrophotographic photoreceptor using an organic photoconductive material has the above-mentioned advantages, but does not satisfy all of the characteristics required as an electrophotographic photoreceptor at a high level. Further improvement in image quality and durability of output images is desired.

  As an effort to improve the image quality of the photoreceptor, many proposals have been made to increase the mobility of the charge transporting substance and to increase the sensitivity of the photoreceptor. In Patent Documents 1 to 3, characteristics such as high sensitivity and low residual potential are expressed by including a charge transporting substance having a specific structure in the photosensitive layer.

With regard to further improvement in image quality, in recent years, in order to further increase the resolution of the output image, the exposure light (image exposure light) irradiated to the electrophotographic photosensitive member is light having a shorter wavelength than that conventionally used (for example, wavelength). There has been proposed to use light) of 380 ~ 450 nm (Patent Document 4). Patent Document 3 also describes the application of a photoreceptor containing a charge transporting substance having a specific structure to short wavelength exposure light.

  On the other hand, with regard to the improvement of durability, polycarbonate resin has been often used as a binder resin for the surface layer of an electrophotographic photoreceptor, but in recent years, polyarylate resin having higher mechanical strength than polycarbonate resin has been used. A proposal has been made to further improve the durability of the electrophotographic photosensitive member by using it (Patent Document 5). The polyarylate resin is one type of aromatic dicarboxylic acid polyester resin.

Furthermore, as a higher strength polyarylate resin, polyarylate resins in which a diphenyl ether dicarboxylic acid structure is introduced into the dicarboxylic acid structure of the polyarylate resin have been proposed (Patent Documents 6 and 7).
JP-A-8-146629 JP 2005-010257 A JP 2000-105475 A Japanese Patent Laid-Open No. 09-240051 Japanese Patent Laid-Open No. 10-039521 JP-A-10-020514 JP 2006-53549 A

  However, in the photoreceptor containing the charge transporting substance disclosed in Patent Documents 1 to 3, a high sensitivity can be achieved. However, the polyarylate resin which is one of the methods for enhancing the durability as the binder resin and the charge transport When a photosensitive layer containing a photosensitive material is produced, it is possible to achieve both high sensitivity and high durability to some extent. Characteristics are not obtained. Similarly, when a polyarylate resin described as a specific example in Patent Document 6 that is expected to be highly durable is contained as a binder resin, there is a tendency for a decrease in charging ability during repeated use. It was. This is because the compatibility between the charge transporting substance having a specific structure capable of increasing the sensitivity and the polyarylate resin is not sufficient, and as a result, a phase separation state is formed in a minute region, resulting in potential fluctuation. It is possible. In addition, it is presumed that the same charge reduction occurs in the photoconductor specifically described in Patent Document 7, and the potential fluctuates for the same reason. Therefore, in producing an electrophotographic photosensitive member that is highly sensitive and durable and does not deteriorate image quality even when used repeatedly, it is necessary to improve the characteristics by combining the structure of the charge transporting substance and the structure of the binder resin. is there.

Furthermore, as a response to short wavelength exposure light that can contribute to high image quality, when a polyarylate resin disclosed in Patent Document 5 is used for the surface layer of an electrophotographic photosensitive member, a highly durable electron Although it can be used as a photographic photoreceptor, a conventional layer containing a polyarylate resin and a charge transporting material has a relatively low transmittance with respect to light with a short wavelength, particularly light with a wavelength of 380 to 450 nm. In some cases, the sensitivity of the body was reduced. In particular, when a polyarylate resin having a terephthalic acid moiety (having a dicarboxylic acid group at the para position on the phenyl group) as a constituent element in the polyarylate resin is included in the surface layer, the transmittance for light of 380 to 450 nm is reduced. Tended to be. This decrease in transmittance with respect to light of 380 to 450 nm does not mean that the transmittance of the polyarylate resin itself is low (light absorption occurs), but is used for the terephthalic acid site in the polyarylate resin and the photoreceptor. Electron transfer between terephthalic acid that has a relatively low unoccupied orbital (LUMO orbit) and an occupied orbital (HOMO orbital) of the charge transporting material It is speculated that there are factors.

  On the other hand, the electrophotographic photosensitive member specifically disclosed in Patent Document 3 has a high transmittance for light of a short wavelength of the surface layer (charge transport layer), and has a short wavelength as exposure light for high image quality. Although it is difficult to cause a decrease in sensitivity when using light, a polycarbonate resin having a mechanical strength inferior to that of polyarylate resin is used as a binder resin for the surface layer, so that it is sufficient in terms of durability. Absent.

The object of the present invention is when durability, high sensitivity, high potential stability even during repeated use, and short-wavelength light, particularly light having a wavelength of 380 to 450 nm, are used as exposure light. It is an object of the present invention to provide an electrophotographic photosensitive member that hardly causes a decrease in sensitivity, and a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

The present invention provides an electrophotographic photosensitive member in which a charge generation layer and a charge transport layer are laminated in this order from the conductive support side on the conductive support.
Charge transport layer, polyarylate resin containing a repeating structural unit represented by the following formula (1), and contains a charge-transporting substance represented by the following formula (A), and,
Repeating structural unit represented by the following formula (1) is, in all the repeating structural units of the polyarylate resin, which is an electrophotographic photosensitive member, characterized in that 60 to 100% molar ratio terms.

(In the formula (1), R ^{11 to} R ¹⁸ and R ^{21 to} R ²⁸ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. X represents a single bond, an oxygen atom, or sulfur. An atom or a divalent group having a structure represented by the following formula (2) is shown.

(In Formula (2), R ³¹ and R ³² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group, or an aryl group, or R ³¹ and R ³² are bonded to each other. cycloalkylidene group formed Te or, shows a fluorenylidene group.))

(In Formula (A), R ^{41 to} R ⁵⁰ each independently represent a hydrogen atom, an alkyl group, or an alkoxy group, and Ar ¹ and Ar ² may each independently have a substituent. Represents an aromatic hydrocarbon group, and Y represents an oxygen atom, a sulfur atom, or a divalent group having a structure represented by the following formula (B).

(In formula (B), R ⁵¹ and R ⁵² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group, or an aryl group, or R ⁵¹ and R ⁵² are bonded to each other. cycloalkylidene group formed Te or, shows a fluorenylidene group.))

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

  According to the present invention, it is possible to provide an electrophotographic photosensitive member having high durability, high sensitivity, and excellent potential stability upon repeated use, and a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

In addition, according to the present invention, an electrophotographic photosensitive member that is less susceptible to a decrease in sensitivity even when light having a short wavelength, particularly light having a wavelength of 380 to 450 nm, is used as exposure light, and the electrophotographic photosensitive member. A process cartridge and an electrophotographic apparatus can be provided.

As described above, the electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor obtained by laminating a charge generation layer and a charge transport layer in this order from the conductive support side on the conductive support.
Charge transport layer, polyarylate resin containing a repeating structural unit represented by the following formula (1), and contains a charge-transporting substance represented by the following formula (A), and,
Repeating structural unit represented by the following formula (1) is, in all the repeating structural units of the polyarylate resin, characterized in that 60 to 100% molar ratio terms.

(In the formula (1), R ^{11 to} R ¹⁸ and R ^{21 to} R ²⁸ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. X represents a single bond, an oxygen atom, or sulfur. An atom or a divalent group having a structure represented by the following formula (2) is shown.

(In Formula (2), R ³¹ and R ³² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group, or an aryl group, or R ³¹ and R ³² are bonded to each other. cycloalkylidene group formed Te or, shows a fluorenylidene group.))

(In Formula (A), R ^{41 to} R ⁵⁰ each independently represent a hydrogen atom, an alkyl group, or an alkoxy group, and Ar ¹ and Ar ² may each independently have a substituent. Represents an aromatic hydrocarbon group, and Y represents an oxygen atom, a sulfur atom, or a divalent group having a structure represented by the following formula (B).

(In formula (B), R ⁵¹ and R ⁵² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group, or an aryl group, or R ⁵¹ and R ⁵² are bonded to each other. cycloalkylidene group formed Te or, shows a fluorenylidene group.))

Examples of the alkyl group of R ^{11 to} R ¹⁸ and R ^{21 to} R ^{28 in} the above formula (1) include a methyl group, an ethyl group, a propyl group, a butyl group, and the alkoxy group includes a methoxy group and an ethoxy group. And propoxy groups, and examples of the aryl group include a phenyl group and a naphthyl group. Among these, a methyl group, an ethyl group, a methoxy group, an ethoxy group, and a phenyl group are preferable.

Examples of the alkyl group represented by R ³¹ and R ^{32 in} the above formula (2) 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, a methyl group, an ethyl group, and the like. Group, propyl group (especially isopropyl group), trifluoromethyl group and pentafluoroethyl group are preferred.

Examples of the cycloalkylidene group formed by combining R ³¹ and R ³² in the above formula (2) include a cyclopentylidene group, a cyclohexylidene group, and a cycloheptylidene group. Among these, a cyclohexylidene group is preferable.

Examples of the alkyl group represented by R ^{41 to} R ^{50 in} the above formula (A) include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. And so on. Among these, a methyl group, an ethyl group, a propyl group (particularly isopropyl group), and a methoxy group are preferable.

Of Ar ¹ and Ar ² in the above formula (A), as the aromatic hydrocarbon group which may have a substituent, the aryl group, a biphenyl group, a naphthyl group, a fluorenyl group, a dibenzofuranyl group, Jibenzochio A phenyl group etc. are mentioned. Among these, an aryl group, a biphenyl group, and a fluorenyl group are preferable. Examples of the substituents possessed by these aromatic hydrocarbon groups include alkyl groups and alkoxy groups. Examples of alkyl groups include methyl, ethyl, propyl, butyl, and alkoxy groups include methoxy, ethoxy, and propoxy. Group, etc., among which a methyl group and an ethyl group are preferable.

Examples of the alkyl group of R ⁵¹ and R ^{52 in} the above formula (B) include a methyl group, an ethyl group, a propyl group, a butyl group, and an isopropyl group. Examples of the fluorinated alkyl group include a trifluoromethyl group and a penta 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. Group, ethyl group, propyl group and isopropyl group are preferred. Examples of the cycloalkylidene group formed by combining R ⁵¹ and R ⁵² in the above formula (B) include a cyclopentylidene group, a cyclohexylidene group, and a cycloheptylidene group. Among these, a cyclohexylidene group is preferable.

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

The polyarylate resin having a repeating structural unit represented by the above formula (1) used for the charge transport layer of the electrophotographic photosensitive member of the present invention has a repeating structural unit represented by the above formula (1) in the polyarylate resin. In the repeating structural unit, the molar ratio is 60 to 100%. Further in the total repeating structural units, not less than 80% at a molar ratio terms, especially in all the repeating structural units, it is preferred in terms such as the improvement of mechanical strength is the molar ratio in terms of 90% or more.

  The polyarylate resin having a repeating structural unit represented by the above formula (1) used for the charge transport layer of the electrophotographic photosensitive member of the present invention is a specific repeating structural unit selected from the above formula (1). And other repeating structural units selected from the above formula (1), or a copolymer of another divalent carboxylic acid and a repeating structural unit composed of a divalent organic residue. . In that case, the polymerization form may be a polymerization form such as block copolymerization or random copolymerization, and is arbitrary, but is preferably a random copolymerization form.

  The polyarylate resin of the present invention is preferably treated with a terminal terminator by adding a terminal terminator during production. The end stopper is arbitrarily selected from commonly used materials (for example, 4-tertiary butylphenol).

  Further, in the present invention, the specific repeating structural unit selected in the above formula (1), the other repeating structural units selected in the above formula (1), or other divalent carboxylic acids. The description that the copolymerization ratio in terms of molar ratio of the copolymerized polyarylate resin having a repeating structural unit composed of an acid and a divalent organic residue is A: B is a specific formula selected from the above formula (1). The dicarboxylic acid ester moiety shown in the repeating structural unit is (1-C), the bisphenol moiety is (1-B), another repeating structural unit selected from the above formula (1), or other divalent carboxylic acid When the dicarboxylic acid ester moiety shown in the repeating structural unit comprising an acid and a divalent organic residue is (3-C) and the bisphenol moiety is (3-B), the dicarboxylic acid ester moiety (1 C): (3-C) is the copolymerization ratio A: B, and the bisphenol moiety (1-B) :( 3-B) in terms of molar ratio is the copolymerization ratio A: B. Yes.

  Examples of the divalent carboxylic acid used in the above repeating structural unit composed of another divalent carboxylic acid and a divalent organic residue include aromatic diesters such as terephthalic acid, isophthalic acid, diphenyldicarboxylic acid, and naphthalenedicarboxylic acid. Carboxylic acids, succinic acid, adipic acid, sebacic acid, linear aliphatic dicarboxylic acids such as dodecanedioic acid, cyclic aliphatic divalent carboxylic acids such as cyclohexylenedicarboxylic acid, etc., among which terephthalic acid, Isophthalic acid, adipic acid and sebacic acid are preferred. 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. Specific examples of repeating structural units composed of other divalent carboxylic acids and divalent organic residues are shown below.

  The polyarylate resin having a repeating structural unit represented by the above formula (1) used in the charge transport layer of the electrophotographic photoreceptor of the present invention preferably has a weight average molecular weight of 80000 or more. Among the polyarylate resins having a repeating 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 likely to be 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 repeating 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 repeating structural unit represented by a repeating structural unit is preferably 300,000 or less, particularly preferably 200,000 or less.

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

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

  The following formula (1-2-1)

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

  In addition to the acid chloride solution, the following formula (1-2-2)

2,2-bis (3-methyl-4-hydroxyphenyl) propane having a structure represented by the following formula is dissolved in a 10% aqueous sodium hydroxide solution, and tributylbenzylammonium chloride as a polymerization catalyst is added thereto and stirred: A 2,2-bis (3-methyl-4-hydroxyphenyl) propane solution was prepared.

  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 mixture was dropped into methanol with stirring to precipitate a polymer, and this polymer was vacuum-dried to obtain a polyarylate resin which is a repeating unit represented by the above formula (1-2). The polystyrene-reduced weight average molecular weight (weight average molecular weight) of this polyarylate resin was 130,000.

(Synthesis Example 2)
Hereinafter, as a synthesis example, in all repeating structural units in the polyarylate resin, 80% in terms of molar ratio is a repeating structural unit represented by the above formula (1-2), and 20% is represented by the above formula (3-2). The synthesis method of the polyarylate resin which is a repeating structural unit shown by this is shown.

  The following formula (1-2-1)

Diphenyl ether dicarboxylic acid chloride having the structure represented by the following formula (3-2-1)

Was mixed in a molar ratio of 8: 2 and dissolved in dichloromethane to prepare a mixed solution of diphenyl ether dicarboxylic acid chloride and terephthalic acid chloride.

  In addition to the acid chloride solution, the following formula (1-2-2)

A 2,2-bis (3-methyl-4-hydroxyphenyl) propane solution having a structure represented by the following formula was prepared.

  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, it is dropped into methanol with stirring to precipitate a polymer, and this polymer is vacuum-dried. In all repeating structural units in the polyarylate resin, 80% in terms of molar ratio is expressed by the above formula (1- A polyarylate resin having the repeating structural unit represented by 2) and 20% of the repeating structural unit represented by the above formula (3-2) was obtained. The polystyrene-reduced weight average molecular weight (weight average molecular weight) of this polyarylate resin was 110,000.

(Synthesis Example 3)
Hereinafter, as a synthesis example, in all repeating structural units in the polyarylate resin, 70% in terms of molar ratio is a repeating structural unit represented by the above formula (1-2), and 30% is represented by the above formula (3-13). The synthesis method of the polyarylate resin which is a repeating structural unit shown by this is shown.

  The following formula (1-2-1)

Diphenyl ether dicarboxylic acid chloride having a structure represented by the following formula (3-13-1)

Were mixed at a molar ratio of 7: 3 and dissolved in dichloromethane to prepare a mixed solution of diphenyl ether dicarboxylic acid chloride and isophthalic acid chloride.

  In addition to the acid chloride solution, the following formula (1-2-2)

2,2-bis (3-methyl-4-hydroxyphenyl) propane having a structure represented by the following formula is dissolved in a 10% aqueous sodium hydroxide solution, and tributylbenzylammonium chloride as a polymerization catalyst is added thereto and stirred: A 2,2-bis (3-methyl-4-hydroxyphenyl) propane solution was prepared.

  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 addition of acetic acid, and washing with water was repeated until the aqueous phase became neutral.

After washing, the solution is added dropwise to methanol with stirring to precipitate a polymer, and this polymer is vacuum-dried. In all the repeating structural units in the polyarylate resin, 70% in terms of molar ratio is represented by the formula (1- a repeating structural unit represented by 2), 30% was obtained polyarylate resin is a repeating structural unit represented by the above formula (3-13). The polystyrene-reduced weight average molecular weight of the polyarylate resin (hereinafter referred to as weight average molecular weight (Mw)) was 120,000.

  In the present invention, the weight average molecular weight of the resin is 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 Mysori disk H-25-5 by Tosoh Corporation was made into the sample for GPC (gel permeation chromatography).

  Next, the column is stabilized in a heat chamber at 40 ° C., tetrahydrofuran is flowed through the column at this temperature at a flow rate of 1 ml / min, 10 μl of 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 the measurement of 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 by several kinds of monodisperse polystyrene standard samples and the count number. As the standard polystyrene sample for preparing a calibration curve, ten points of Aldrich monodisperse polystyrene having molecular weights of 3500, 12000, 40000, 75000, 98000, 120,000, 240000, 500,000, 800,000 and 1800000 were used. An RI (refractive index) detector was used as the detector.

The copolymerization ratio of the resin which is a copolymer of the resin of the present invention is confirmed by a conversion method based on a peak area ratio of hydrogen atoms constituting the resin by ¹ H-NMR measurement of the resin, which is a general technique. Thus, the copolymerization ratio is confirmed.

  Specific examples of the charge transporting substance represented by the above formula (A) are shown below.

  Among these, (A-2), (A-5), (A-6), (A-8), (A-9), (A-13), (A-15), (A-16) ), (A-19), (A-23), and (A-26) are preferable as the charge transporting material of the photoreceptor having the charge transporting layer containing the polyarylate resin described in the present invention. Furthermore, (A-5), (A-8), (A-15), and (A-23) are preferable.

  The charge transporting material represented by the above formula (A) is produced by a coupling reaction (for example, Ullmann reaction) between an amine compound and an aromatic halide, which is a normal production method. Although a manufacturing example is shown below, a manufacturing method is not limited to this.

(Synthesis Example 4) Synthesis of a charge transporting substance having the structure represented by the above formula (A-5) In a 200 ml three-necked flask equipped with a Dimro-type condenser, thermometer, and stirrer, 4-[(4 -Aminophenyl) cyclohexyl] phenylamine 13.3 g (0.05 mol), 11.0-bromo-4-methylbenzene (0.24 mol) as a halogenated aromatic compound, 32.6 g of sodium-tertiary butoxide as a base (0.42 mol), 1.5 g (0.005 mol) of tri- (o-tolyl) phosphine as a phosphorus compound, 0.112 g (0.0005 mol) of Pd (Oac) ₂ as a metal-containing compound, and 90 ml of xylene as a solvent. In addition, the mixture was heated to 130 ° C. in an oil bath, stirred for 1 hour to react, and then allowed to cool to room temperature.

  Next, the reaction solution was neutralized with hydrochloric acid, toluene was added, the organic layer was treated with alumina and dried over calcium chloride, and then the organic solvent was distilled off.

  The obtained crude product was purified by a silica gel column using 10 times the amount of silica gel as the composition amount and a mixed solvent of toluene / hexane = 1/1 as a developing solvent, and the above formula (A-5) 27.6 g of a charge transport material having the structure shown was obtained (yield: 88% by mass).

  (Synthesis Example 5) A charge transporting substance having a structure represented by the above formula (A-8) was synthesized by the following procedure.

  (Step 1) While stirring 100 g (376 mmol) of 1,1-bis (4-aminophenyl) cyclohexane in 1000 ml of toluene, 140 g (1.1 mol) of acetic anhydride was added dropwise. After completion of the dropwise addition, the temperature was raised to 110 ° C. and refluxed, followed by filtration after completion of the reaction, and washing with toluene to obtain a compound having a structure represented by the following formula (Int-1). The yield was 90 g (yield 69% by mass).

  (Step 2) 70 g (200 mmol) of a compound having a structure represented by the above formula (Int-1), 140 g (642 mmol) of 3-iodotoluene, 55 g (398 mmol) of potassium carbonate and 38 g (598 mmol) of a copper catalyst were mixed. While stirring in 250 ml of o-dichlorobenzene, the mixture was heated to 190 ° C. and refluxed. The reaction was performed for 12 hours. After completion of the reaction, 400 ml of toluene was added, filtered while hot, washed, and then the solvent was distilled off under reduced pressure to obtain a compound having a structure represented by the following formula (Int-2). The yield was 113 g (the yield was 107% by mass, but the remaining o-dichlorobenzene was included).

  (Step 3) 98 g (185 mmol) of the compound having the structure represented by the above formula (Int-2), 85 g (1.57 mol) of sodium methylate and 9.3 g (520 mmol) of water are mixed and in 500 ml of methyl cellosolve. While stirring, the temperature was raised to 110 ° C. and refluxed for 5 hours. After completion of the reaction, the mixture was poured into 1.8 l of water, washed, and the organic layer was extracted with a separatory funnel. Toluene was added to the extract, washed with water and extracted twice. Thereafter, the solvent was distilled off under reduced pressure to obtain a compound having a structure represented by the following formula (Int-3). The yield was 76 g (yield 85.1% by mass).

  (Step 4) Compound 23g (51 mmol) having a structure represented by the above formula (Int-3), 29 g (125 mmol) of 3,4-dimethyliodobenzene, 19 g (128 mmol) of potassium carbonate and 11 g (153 mmol) of copper catalyst are mixed. The mixture was heated to 190 ° C. with stirring in 85 ml of o-dichlorobenzene and refluxed. The reaction was performed for 12 hours. After completion of the reaction, 200 ml of toluene was added, filtered while hot, washed, and then the solvent was distilled off under reduced pressure. The obtained residue was purified by developing with silica gel column chromatography with toluene / n-hexane = 1/3 to obtain a crude product. Furthermore, after heating and dissolving using a mixed solvent of toluene / n-hexane, the mixture was cooled and recrystallized. This recrystallization step was repeated twice to obtain a charge transporting substance having a structure represented by the above formula (A-8) as a product. The yield was 23 g (yield 69.0% by mass).

  The content of the charge transporting material represented by the above formula (A) contained in the charge transporting layer of the present invention in the charge transporting layer is arbitrary, but in order to fully develop the characteristics of the charge transporting material. Is preferably contained in an amount of 20% by mass or more based on the total solid content in the charge transport layer.

  The mass ratio of the charge transporting material represented by the above formula (A) contained in the charge transporting layer of the present invention and the polyarylate resin of the present invention is arbitrary, but the characteristics of the charge transporting material are fully expressed. For this purpose, the mass ratio of the charge transporting substance to the polyarylate resin is preferably 60% by mass or more. In addition, by including the polyarylate resin of the present invention, the mass ratio of the charge transporting substance to the polyarylate resin may be increased, and in order to express high mechanical strength, it is preferably 140% by mass or less.

The electrophotographic photoreceptor of the present invention contains a polyarylate resin in which the charge transport layer contains at least a repeating structural unit represented by the above formula (1), and a charge transporting material represented by the above formula (4), and In the electrophotographic photosensitive member, the repeating structural unit represented by the above formula (1) is 60 to 100% in terms of molar ratio in all repeating structural units of the polyarylate resin. Further, in order to improve the characteristics of the electrophotographic photosensitive member, it is preferable that the transmittance of the charge transport layer is 95% or more at a wavelength of 680 nm of the charge transport layer. The transmittance at a wavelength of 680 nm of the charge transport layer in the present invention is the transmittance of the charge transport layer of the present invention having the same thickness when the resin constituting the charge transport layer having a thickness of 10 μm is contrasted. Show. Since the charge transporting material used in a general photoreceptor does not absorb the charge transporting material itself at a wavelength of 680 nm, the transmittance of the charge transporting layer at a wavelength of 680 nm is low. Demonstrate that light transmittance due to light scattering due to factors such as aggregation or surface roughness in the transport layer, or light scattering due to white turbidity due to a decrease in compatibility between the charge transport material and the binder (lower transmittance) Yes. In the charge transport layer of the electrophotographic photoreceptor of the present invention, the transmittance does not decrease due to factors such as scattering due to surface roughness of the charge transport layer and white turbidity due to a decrease in compatibility between the charge transport material and the binder. Rate charge transport layer is produced.

  The electrophotographic photoreceptor of the present invention contains a polyarylate resin containing a repeating structural unit represented by the above formula (1) and a charge transporting material represented by the above formula (A) in the charge transporting layer. It is possible to prevent a decrease in charging ability due to the compatibility between the charge transporting material and the binder in the transport layer, and this effect can prevent image deterioration such as fogging during repeated use. . Although it has not been clarified in detail with respect to a decrease in charging ability by containing at least a polyarylate resin containing a repeating structural unit represented by the above formula (1) and a charge transporting material represented by the above formula (A). It is considered that this is derived from the fact that the improvement of the compatibility suppresses the aggregation of minute charge transporting substances and does not cause charge accumulation.

  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 is a laminated type separated into a support and a charge generation layer containing a charge generation material provided on the support and a charge transport layer containing a charge transport material. It is a (functional separation type) and is a normal layer type photosensitive layer in which a charge generation layer and a charge transport layer are laminated in this order from the support side. Furthermore, a protective layer intended to protect the charge transport layer may be provided on the charge transport layer.

  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.

  A conductive layer may be provided between the support and the charge generation layer or an intermediate layer to be described later for the purpose of preventing interference fringes due to scattering of laser light or the like and covering the scratches on the support.

  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 film thickness of the conductive layer is preferably 1 to 40 μm, and particularly 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 charge generation layer. The intermediate layer is formed for improving the adhesion of the charge generation layer, improving the coating property, improving the charge injection property from the support, protecting the charge generation layer from electrical breakdown, and the like.

  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, phenol resin, butyral resin, polyacrylate resin, polyacetal resin, polyamideimide 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, aluminum oxide, etc. It can be formed using the material.

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

  Examples of the charge generating material used in the electrophotographic photosensitive member 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, Dyes and, and cadmium sulfide, zinc oxide and the like. These charge generation materials may be used alone or in combination of two or more.

  Examples of the binder resin used for the charge generation layer include acrylic resin, allyl resin, alkyd resin, epoxy resin, diallyl phthalate resin, silicone resin, styrene-butadiene copolymer, 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 resin, vinyl chloride resin and the like. In particular, a butyral resin is preferable. These can be used singly or in combination of two or more as a mixture or copolymer.

  The charge generation layer can be formed by applying a charge generation layer coating solution obtained by dispersing a charge generation material together with a binder resin 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, particularly 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.

The charge transporting layer of the present invention contains at least a repeating structural unit represented by the above formula (1) as a binder resin in a polyarylate resin in a molar ratio of 60 to 100% in all repeating structural units. Resin is used. 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 repeating structural unit represented by the above formula (1) in the charge transport layer is all of the polyarylate resin. In the repeating structural unit, the proportion of the polyarylate resin contained in a molar ratio of 60 to 100% 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 preferable that it is 70 mass% or more. Examples of resins that can be used in combination include acrylic resins, acrylonitrile resins, allyl resins, alkyd resins, epoxy resins, silicone resins, phenol resins, phenoxy resins, butyral resins, polyacrylamide resins, polyacetal resins, polyamideimide resins, polyamide resins, 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, Examples include vinyl chloride resin and vinyl acetate resin. In particular, polyarylate resin, polycarbonate resin and the like are preferable. These can be used singly or in combination of two or more as a mixture or copolymer.

Further, at least the charge transporting material represented by the above formula (A) is contained as the charge transporting material. Other charge transporting materials shown below can be used in combination as long as the effects of the present invention are not impaired. Examples of charge transportable substances that can be used in combination include triarylamine compounds, hydrazone compounds, styryl compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, excluding the charge transportable substances represented by the above formula (A) of the present invention, And triarylmethane compounds.

  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.

Solvents used for the preparation of the charge transport layer of the electrophotographic photoreceptor according to the present invention include ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as methyl acetate and ethyl acetate; aromatic carbonization such as toluene, xylene and chlorobenzene. Hydrogen solvents; ether solvents such as 1,4-dioxane and tetrahydrofuran; hydrocarbon solvents such as chloroform substituted with halogen atoms; These solvents may be used alone or in combination of two or more. Among these solvents, it is preferable to use an ether solvent or an aromatic hydrocarbon solvent in terms of resin solubility. In producing the charge transport layer, these solvents are used in combination with a polyarylate resin having a repeating structural unit represented by the above formula (1) and a charge transport material represented by the above formula (A). Thus, an electrophotographic photosensitive member that is excellent in properties and is less likely to cause potential fluctuations even during repeated use is obtained.

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

  Further, as described above, a protective layer may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. The protective layer can be formed by applying a protective layer coating solution obtained by dissolving a binder resin in a solvent and drying the coating solution.

  The thickness of the protective layer is preferably 0.5 to 10 μm, and particularly preferably 1 to 5 μm.

  When applying the coating liquid for each of the above layers, for example, a coating method such as a dip coating method (dip coating method), a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, a blade coating method, or the like should be used. Can do.

  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 rotationally driven is uniformly charged to a predetermined positive or negative potential by a charging unit (primary charging unit: charging roller or the like) 3, and then subjected to slit exposure, laser beam scanning exposure, or the like. Exposure light (image exposure light) 4 output from exposure means (not shown) 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 a transfer material supply means (not shown) to the electrophotographic photoreceptor 1 and the transfer means by a transfer bias from a transfer means (transfer roller or the like) 6. 6 (contact portion) is sequentially transferred onto a transfer material (paper or the like) P taken out and fed in synchronization with the rotation of the electrophotographic photosensitive member 1.

  The transfer material P that has received the transfer of the toner image is separated from the 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 transfer, and further from a pre-exposure means (not shown). After being subjected to charge removal processing by pre-exposure light (not shown), it 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 are housed in a container and integrally combined as a process cartridge. The process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. In FIG. 1, an electrophotographic photosensitive member 1, a charging unit 3, a developing unit 5 and a cleaning unit 7 are integrally supported to form a cartridge, and an electrophotographic apparatus is provided 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 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 first color electrophotographic photoreceptor 1Y that is rotationally driven 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, and then slits Exposure light (image exposure light) 4Y output from exposure means (not shown) such as exposure and 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 development means 5Y and first color The transfer unit 6Y is collectively referred to as a first color image forming unit.

  Second color electrophotographic photoreceptor 1M, second color charging means 3M, second color exposure means for outputting exposure light 4M corresponding to the second color component image, second color developing means 5M, and second color A second color image forming portion having a transfer means 6M, a third color electrophotographic photosensitive member 1C, a third color charging means 3C, and a third color output device that outputs exposure light 4C corresponding to the third color component image. Third color image forming unit having exposure means, third color developing means 5C and third color transfer means 6C, fourth color electrophotographic photoreceptor 1K, fourth color charging means 3K, fourth color component The operation of the fourth color image forming unit having the fourth color exposure unit that outputs the exposure light 4K corresponding to the image, the fourth color development unit 5K, and the fourth color transfer unit 6K is the first color image. The operation is the same as that of the forming unit. The second color toner image (magenta toner image), a third color toner image (cyan toner image), a fourth color toner image (black toner image) 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, introduced into the fixing means 8, and subjected to image fixing to be printed out of the apparatus as a 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 As shown in FIG. 3, the first to fourth color charging units 3Y, 3M, 3C, and 3K are contact charging units using a charging roller or the like. In this case, pre-exposure is not always necessary.

  Among the above-described components such as the electrophotographic photosensitive member, charging unit, developing unit, transfer unit, and cleaning unit, a plurality of components are housed in a container and integrally combined as a process cartridge. Or an electrophotographic apparatus main body such as a laser beam printer. In FIG. 3, 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 is provided. 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 “weight average molecular weight”.

[Example 1-1]
An aluminum cylinder having a diameter of 30 mm and a length of 260.5 mm was used as a support.

Next, SnO ₂ coat-treated barium sulfate (conductive particles) 10 parts, titanium oxide (resistance pigment) 2 parts, phenol resin (binder resin) 6 parts, silicone oil (leveling agent) 0.001 part and methanol A conductive layer coating solution was prepared using a mixed solvent of 4 parts / 16 parts of methoxypropanol.

  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, an intermediate layer coating solution was prepared by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol.

  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 a solution of 5 parts of polyvinyl butyral resin (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) Dispersion was performed in a 23 ± 3 ° C. atmosphere for 1 hour with a sand mill using glass beads having a diameter of 1 mm, and after dispersion, 250 parts of ethyl acetate was added to prepare a charge generation layer coating solution.

  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, 9 parts of a charge transporting substance having a structure represented by the exemplary structure (A-8) and 10 parts of a polyarylate resin (Mw: 130000) having a repeating structural unit represented by the above formula (1-2) Was dissolved in 80 parts of a mixed solution of chlorobenzene and dimethoxymethane (mass ratio 7: 3) to prepare a coating solution for a charge transport layer.

  This charge transport layer coating solution was dip coated on the charge generation layer and dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 18 μm.

  Further, the coating liquid used for the charge transport layer is formed on a polyethylene terephthalate film using a Mayer bar to prepare a charge transport layer having a thickness of 20 μm, and the charge transport layer is peeled off from the polyethylene terephthalate film to be compatible. A sample for evaluation was used.

  Next, evaluation will be described.

  The compatibility of the charge transport layer was determined by measuring the transmittance of the charge transport layer and using the degree of scattering due to microaggregation as an index. The transmittance of the charge transport layer was measured using an ultraviolet-visible spectrophotometer (V-570) manufactured by JASCO Corporation. Only the polyarylate resin having the repeating structural unit represented by the above formula (1-2) used in Example (1-1) was dissolved in a mixed solution of chlorobenzene and dimethoxymethane, and a Meyer bar was formed on the polyethylene terephthalate film. Was used to prepare a resin film having a thickness of 20 μm. The resin film was peeled from the polyethylene terephthalate film and used as a control sample for measuring transmittance. The transmittance was measured using the charge transport layer as a control sample for measuring transmittance and a sample for evaluating compatibility. In the transmittance measurement, the transmittance at a wavelength of 680 nm was used as an evaluation value.

  The produced electrophotographic photosensitive member was evaluated according to the following.

  As an evaluation apparatus, a laser beam printer LBP-2510 manufactured by Canon Inc. (charging (primary charging): contact charging method, process speed: 94.2 mm / s), charging potential (dark part potential) of the electrophotographic photosensitive member is used. It was modified so that it could be adjusted.

  The evaluation was performed in an environment of room temperature 25 ° C. and humidity 30%.

The exposure amount (image exposure amount) of the 780 nm laser light source of the evaluation apparatus was set so that the light amount on the surface of the electrophotographic photosensitive member was 0.3 μJ / cm ² .

  To measure the surface potential (dark part potential and bright part potential) of the electrophotographic photosensitive member, replace the jig and the developing device fixed so that the potential measuring probe is positioned 130 mm from the end of the electrophotographic photosensitive member. Then, it was carried out at the developing unit position.

  The dark part potential (VD1) of the non-exposed part of the electrophotographic photosensitive member was set to −550 V and evaluated. Further, 5000 images were output continuously using A4 size plain paper, and after 5000 images were output, the amount of scraping from the initial surface of the electrophotographic photosensitive member was measured to evaluate durability. Further, the dark part potential (VD2) after outputting 5000 images was measured, and the difference (ΔVD) between the initial dark part potential (VD1) and the dark part potential (VD2) after 5000 sheets was evaluated. 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.

[Examples 1-2 to 1-33, Comparative Examples 1-1 to 1-12]
In Example [1-1], the electrophotographic photosensitive member and the transmittance were the same as Example [1-1] except that the charge transporting material and the binder resin of the charge transporting layer were as shown in Table 1. A charge transport layer for measurement was prepared and evaluated. The results are shown in Table 2.

  (C-1) in Table 1 is a polycarbonate resin having the structure shown below.

  Further, (D-1) and (D-2) in Table 1 are charge transporting materials having the structures shown below.

  As is apparent from a comparison of Examples and Comparative Examples, in the electrophotographic photoreceptor according to the present invention containing the charge transporting material represented by the above formula (A) of the present invention, poly Depending on the structure of the arylate resin, the film properties and electrophotographic characteristics of the photoreceptor differed. When the results are compared in detail, from the results of Examples and Comparative Examples [1-1] to [1-6], the dicarboxylic acid portion of the polyarylate resin is a phase between the charge transporting material and the polyarylate resin in the present invention. It is suggested that it affects the solubility. In the polyarylate resin of the present invention, the characteristics are improved by using a dicarboxylic acid having a specific structure as the dicarboxylic acid moiety. Further, from the results of Examples and Comparative Examples [1-5] and [1-6], it is more preferable to introduce an ether structure into the dicarboxylic acid portion of the polyarylate resin than to introduce an ether bond into the bisphenol or biphenol moiety. It has been shown to be effective in improving electrophotographic characteristics.

  In addition, as for the charge transporting substance, when the Examples and Comparative Examples [1-7] to [1-10] are compared, the charge transporting substance similar to the charge transporting substance represented by the above formula (A) is used. Even so, the compatibility is changed by the combination with the binder resin, and the superiority of the combination of the polyarylate resin of the present invention and the charge transporting substance represented by the above formula (A) is seen. Further, regarding the durability of the photoconductor, when the example is compared with the comparative example [1-11] and the comparative example [1-12], the durability is higher in the example than the polycarbonate resin shown in the comparative example. It is shown to have sex.

[Example 2-1]
An aluminum plate having a length of 150 mm and a width of 150 mm was used as a support.

  Next, an intermediate layer coating solution was prepared by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol.

  This intermediate layer coating solution was applied on 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, the following formula (CGM-1)

20 parts of an azo pigment (charge generating material) having a structure represented by the following formula and 10 parts of butyral resin (degree of butyralization: 65 mol%) are added to 400 parts of tetrahydrofuran, and the atmosphere is 23 ± 3 ° C. in a sand mill using glass beads having a diameter of 1 mm. The coating solution for charge generation layers was prepared by dispersing for 20 hours.

  The 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, 9 parts of a charge transporting substance having a structure represented by the exemplary structure (A-8) and 10 parts of a polyarylate resin (Mw: 130000) having a repeating structural unit represented by the above formula (1-2) Was dissolved in 80 parts of a mixed solution of chlorobenzene and dimethoxymethane (mass ratio 7: 3) to prepare a coating solution for a charge transport layer.

  The charge transport layer coating solution was dip-coated on the charge generation layer and dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 20 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 surface potential of the electrophotographic photosensitive member is charged to −600 V (dark portion potential) with a corona charger, and then light (exposure) is irradiated with light having wavelengths of 400 nm, 430 nm, and 450 nm with an LED, and the surface potential is − The amount of light required to attenuate to 300 V (bright part potential) was measured, and the half exposure sensitivity (E _1/2 ) was calculated at each wavelength.

The results are shown in Table 4. In Table 4, the sensitivity to light with a wavelength of 400 nm is E _{1/2 (400)} , the sensitivity to light with a wavelength of 430 nm is E _{1/2 (430),} and the sensitivity to light with a wavelength of 450 nm is E _{1/2 ( 450)} .

[Examples 2-2 to 2-33, Comparative examples 2-1 to 2-8]
In Example [2-1], the charge transport layer was a surface layer in the same manner as in Example [2-1], except that the charge transporting substance and binder resin of the charge transport layer were as shown in Table 3. An electrophotographic photoreceptor was prepared and evaluated. The results are shown in Table 4.

  (C-1) in Table 3 is a polycarbonate resin having the structure shown below.

  Further, (D-2) in Table 3 is a charge transporting substance having the structure shown below.

  From the comparison between Examples and Comparative Examples [2-1] and [2-2], a resin having a repeating structural unit in the present invention is used, and a resin having a molar ratio in the present invention is used. In this case, the characteristics are good when image exposure in a short wavelength region is used, indicating that the photoreceptor of the present invention is suitable for an electrophotographic photoreceptor using short wavelength region image exposure. Further, from the comparison between Examples and Comparative Examples [2-3] to [2-6], an electrophotographic photosensitive member containing a conventional resin containing many terephthalic acid structures in the resin structure used for the charge transport layer. And the polyarylate resin of the present invention show that the electrophotographic photosensitive member of the present invention has significantly improved characteristics. Further, by comparing the Examples with Comparative Examples [2-7] and [2-8], the photoreceptor containing the repeating structural unit resin and the charge transporting material in the present invention was subjected to short wavelength image exposure. It is shown to be suitable for an electrophotographic photoreceptor using

FIG. 3 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. 2 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 P Transfer material 1Y First color electrophotographic photoreceptor 1M Second color electrophotography Photoconductor 1C Third color electrophotographic photosensitive member 1K Fourth color electrophotographic photosensitive member 2Y Axis 2M Axis 2C Axis 2K Axis 3Y First color charging means 3M Second color charging means 3C Third color charging means 3K 4th color charging means 4Y exposure light 4M exposure light 4C exposure light 4K exposure light 5Y first color developing means 5M second color developing means 5C third color developing means 5K fourth color developing 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 third color cleaning means 7K for fourth color Krini Grayed means 9Y process cartridge 9M process cartridge 9C process cartridge 9K process cartridge 12 tension roller 14 the transfer material transport member

Claims (8)

Has an electrically conductive support and a photosensitive layer formed on the conductive support member, multi-layer type photosensitive layer of the photosensitive layer is formed by laminating a charge generation layer and a charge transport layer from the conductive support side in this order In the electrophotographic photosensitive member,
The charge transport layer contains a polyarylate resin containing a repeating structural unit represented by the following formula (1), a charge transporting material represented by the following formula (A), and
The electrophotographic photosensitive member (wherein the photosensitive layer is composed of 60 to 100% in terms of molar ratio) of the repeating structural unit represented by the following formula (1) in all repeating structural units of the polyarylate resin When the charge transport material represented by the following formula (A2) is contained, the charge transport layer is a binder resin having a repeating structure represented by the following formula (A4) (viscosity average molecular weight 31000) and the following formula (CTM-2). And a case where the photosensitive layer contains a compound represented by the following formula (B1)) .

(In the formula (1), R ^{11 to} R ¹⁸ and R ^{21 to} R ²⁸ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. X represents a single bond, an oxygen atom, or sulfur. An atom or a divalent group having a structure represented by the following formula (2) is shown.

(In Formula (2), R ³¹ and R ³² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group, or an aryl group, or R ³¹ and R ³² are bonded to each other. A cycloalkylidene group or a fluorenylidene group formed by

(In Formula (A), R ^{41 to} R ⁵⁰ each independently represent a hydrogen atom, an alkyl group, or an alkoxy group, and Ar ¹ and Ar ² may each independently have a substituent. Represents an aromatic hydrocarbon group, and Y represents an oxygen atom, a sulfur atom, or a divalent group having a structure represented by the following formula (B).

(In formula (B), R ⁵¹ and R ⁵² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group, or an aryl group, or R ⁵¹ and R ⁵² are bonded to each other. A cycloalkylidene group or a fluorenylidene group formed by

(In formula (A2), Ar ⁴ and Ar ⁵ represent an arylene group which may have a substituent, and Ar ^{6 to} Ar ⁹ represent an aryl group which may have a substituent . Ar ^4, Ar ⁵ may form a condensed polycyclic group bonded to one ^another, Ar ^4, Ar ^6, a plurality of groups selected from Ar ^7, and ^{Ar 5,} a plurality of groups selected from Ar 8, Ar ⁹ May be bonded to each other to form a condensed polycyclic group, and at least one of Ar ^{6 to} Ar ⁹ has a substituent represented by the following formula (A3).

(In formula (3), s represents an integer of 0 to 4, R ^{2 to} R ⁴ represent a hydrogen atom or an alkyl group which may have a substituent, and R ^{5 to} R ⁶ represent a hydrogen atom. Represents an alkyl group which may have a substituent, or an aryl group which may have a substituent, and each may be independently different.))



(In Formula (B1), R ¹ represents a group having a chiral center, and R ² represents a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent. R ³ and R ⁴ each independently represents an alkylene group that may have a substituent, or an arylene group that may have a substituent, and R ⁵ , R ⁶ , R ⁷ , And R ⁸ each independently represents an optionally substituted alkyl group or an optionally substituted aryl group, and at least one of R ^{5 to} R ⁸ has a substituent. An aryl group.)
The electrophotographic photosensitive member according to 請 Motomeko 1 transmittance Ru der 95% or more at a wavelength of 680nm of the charge transport layer. Y in front above formula (A) is a divalent group having a structure represented by the formula (B), R ⁵¹ and ^{R 52} in the front above formula (B) is an ^{R 51} and ^{R 52} There electrophotographic photosensitive member according to 請 Motomeko 1 or 2 Ru cyclohexylidene group der cycloheteroalkyl which is formed by bonding. The polyarylate resin before following formula contained (1) the repeating structural unit represented by the said polyarylate all repeating in the structural units of the resin, 請 Motomeko 1-3 Ru 80-100% der in molar ratio terms The electrophotographic photosensitive member according to any one of the above. Wherein the poly weight average molecular weight of polyarylate resin (Mw) is an electrophotographic photosensitive member according to any of 80000 ≦ Mw ≦ 300000 Der Ru請 Motomeko 1-4. The electrophotographic photosensitive member according to any one of claims 1 to 5, and charging means, at least one means selected from the group consisting of the developing means and the cleaning means integrally supported, detachably attached to an electrophotographic apparatus main body Process cartridge characterized by being. The electrophotographic photosensitive member according to any one of claims 1 to 5, a charging means, an exposure means, a developing means, an electrophotographic apparatus, characterized in that it comprises a transfer means and a cleaning means. The electrophotographic apparatus according to claim 7 , wherein the exposure unit is a unit for irradiating the electrophotographic photosensitive member with light having a wavelength of 380 to 450 nm as exposure light.