JP6700832B2 - Electrophotographic photoreceptor, method of manufacturing electrophotographic photoreceptor, process cartridge, and electrophotographic apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member, a method of manufacturing the electrophotographic photosensitive member, a process cartridge using the electrophotographic photosensitive member, and an electrophotographic apparatus.

  An electrophotographic photoreceptor having a charge transport layer as a surface layer is required to have abrasion resistance against repeated use. In order to improve the wear resistance of the charge transport layer, the structure of a resin used as a binder of the charge transport layer, particularly a polycarbonate resin has been studied (Patent Documents 1 to 5).

JP, 2011-26574, A JP 05-113680 A JP 04-149557 A JP-A-06-011877 JP, 2005-338446, A

  According to the study by the present inventors, it has been found that when an electrophotographic photosensitive member having a charge transport layer as a surface layer is used, the charge transport layer becomes thin due to abrasion due to repeated use, and the electric field strength increases. As a result, it has been found that there is a technical problem that a phenomenon of "fog" (a phenomenon in which a small amount of toner is developed in a portion where toner should not be originally developed) occurs in an image.

  In the electrophotographic photoreceptors having the charge transport layer using the conventional polycarbonate resin as the binder described in Patent Documents 1 to 5, although fogging is suppressed to some extent, the electrophotographic photoreceptors that have been particularly required in recent years It was not able to fully cope with the extension of the service life.

  Therefore, an object of the present invention is to provide an electrophotographic photosensitive member having a high level of fogging suppressing effect. Another object of the present invention is to provide a method of manufacturing the electrophotographic photosensitive member, and a process cartridge and an electrophotographic apparatus using the electrophotographic photosensitive member.

The above object is achieved by the present invention described below. That is, the electrophotographic photosensitive member according to the present invention has a support, a charge generating layer, and a charge transporting layer containing a charge transporting substance in this order, and the charge transporting layer is the surface of the electrophotographic photosensitive member. a layer, charge transport layer, possess a structural unit selected from group a, a structural unit selected from group B, a, and,
Weight average molecular weight, has contains a copolymerization port polycarbonate resin is 30,000 98,000 or less,
The ratio of the number of parts between the charge transport material and the copolymerized polycarbonate resin is 6/10 or more and 9/10 or less .

  <Group A: Structural units represented by formulas (101) and (102)>

In (formula ^{(101), R} 211 ~R ²¹⁴ are each independently a hydrogen atom, an alkyl group, an aryl group, ^{.R 215} of an alkoxy group, an alkyl group, an aryl group, and ^{.R 216} to an alkoxy group R ²¹⁷ each independently represent an alkyl group having 1 to 9 carbon atoms ^{.i 211} represents an integer of 0 to 3. ^However, the _{^{R 215 (CH 2) i CHR}} 216 R 217 are not the same.)

(In the formula (102), R ^{221 to} R ²²⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. R ²²⁵ and R ²²⁶ each independently represent an alkyl group having 1 to 9 carbon atoms. Group, provided that R ²²⁵ and R ²²⁶ are not the same. i ²²¹ represents an integer of 0 to 3.)

<B Group: Equation (10 4) shows a structural unit>

(In the formula (104), R ^{241 to} R ²⁴⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. X represents a single bond, an oxygen atom, a sulfur atom, or a sulfonyl group.)

  According to the present invention, it is possible to provide an electrophotographic photosensitive member having a high level of fogging suppressing effect. Further, it is possible to provide a method for manufacturing the electrophotographic photosensitive member, and a process cartridge and an electrophotographic apparatus using the electrophotographic photosensitive member.

FIG. 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having an electrophotographic photosensitive member. It is a powder X-ray diffraction pattern of the droxygallium phthalocyanine crystal used in the Example. It is a powder X-ray diffraction pattern of the chlorogallium phthalocyanine crystal used in the Example. It is a powder X-ray diffraction pattern of the hydroxygallium phthalocyanine crystal used in the examples. It is a figure explaining a 1-dot Keima pattern image.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments. As a result of the studies by the present inventors, it was found that the use of an electrophotographic photoreceptor having a charge transport layer containing a specific polycarbonate resin can improve mechanical strength particularly and suppress fogging at a high level. .. Specifically, it is an electrophotographic photoreceptor having a support, a charge generation layer, and a charge transport layer containing a charge transport material in this order, wherein the charge transport layer is a surface layer of the electrophotographic photoreceptor. And the charge transport layer contains a polycarbonate resin having a structural unit selected from the group A and a structural unit selected from the group B.

  <Group A: Structural units represented by formulas (101) and (102)>

In formula (101), R ^{211 to} R ²¹⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. R ²¹⁵ represents an alkyl group, an aryl group or an alkoxy group. R ²¹⁶ and R ²¹⁷ each independently represent a substituted or unsubstituted alkyl group having 1 to 9 carbon atoms. ⁱ²¹¹ shows the integer of 0-3. When i ²¹¹ is 0, it is a single bond. However, R ²¹⁵ and (CH ₂ ) _i CHR ²¹⁶ R ²¹⁷ are not the same.

In the above formula (102), R ^{221 to} R ²²⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. R ²²⁵ and R ²²⁶ each independently represent a substituted or unsubstituted alkyl group having 1 to 9 carbon atoms. However, R ²²⁵ and R ²²⁶ are not the same. i ²²¹ represents an integer of 0 to 3. When i ²²¹ is 0, it is a single bond.

  <Group B: Structural units represented by formula (104), formula (105), and formula (106)>

In formula (104), R ^{241 to} R ²⁴⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. X represents a single bond, an oxygen atom, a sulfur atom, or a sulfonyl group.

In formula (105), R ^{251 to} R ²⁵⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. R ^{256 to} R ²⁵⁷ each independently represent a hydrogen atom, an alkyl group, an aryl group or a halogenated alkyl group. The aryl group may be substituted with an alkyl group, an alkoxy group, or a halogen atom.

In formula (106), R ^{261 to} R ²⁶⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. W represents a cycloalkylidene group having 5 to 12 carbon atoms. The cycloalkylidene group may be substituted with an alkyl group.

  Examples of the method for synthesizing the polycarbonate resin having the structural unit selected from the group A and the structural unit selected from the group B include the following two methods. First, at least one bisphenol compound selected from the formulas (107) and (108) and at least one bisphenol compound selected from the formulas (110) to (112) are directly reacted with phosgene. Method (phosgene method). Second, transesterification of at least two bisphenol compounds described above with bisaryl carbonates such as diphenyl carbonate, di-p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, and dinaphthyl carbonate. This is a reaction method (transesterification method).

  In the phosgene method, usually, at least two bisphenol compounds described above are reacted with phosgene in the presence of an acid binder and a solvent. Examples of the acid binder used at this time include pyridine and hydroxides of alkali metals such as potassium hydroxide and sodium hydroxide. Examples of the solvent include methylene chloride and chloroform. Further, in order to accelerate the polycondensation reaction, a catalyst or a molecular weight modifier may be added. Examples of the catalyst include tertiary amines such as triethylamine, and quaternary ammonium salts. Examples of the molecular weight modifier include monofunctional compounds such as phenol, p-cumylphenol, t-butylphenol, and long-chain alkyl-substituted phenol.

  Further, when synthesizing the polycarbonate resin, an antioxidant such as sodium sulfite or hydrosulfite; a branching agent such as phloroglucin or isatin bisphenol may be used. The reaction temperature when synthesizing the polycarbonate resin is preferably 0 to 150°C, more preferably 5 to 40°C. While the reaction time depends on the reaction temperature, it is usually 0.5 minutes to 10 hours, more preferably 1 minute to 2 hours. Further, during the reaction, the pH of the reaction system is preferably 10 or higher.

  Hereinafter, specific examples of the bisphenol compound used for the synthesis will be shown.

  (1) At least one bisphenol compound selected from formulas (107) and (108)

In formula (107), R ^{211 to} R ²¹⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. R ²¹⁵ represents an alkyl group, an aryl group or an alkoxy group. R ²¹⁶ and R ²¹⁷ each independently represent a substituted or unsubstituted alkyl group having 1 to 9 carbon atoms. ⁱ²¹¹ shows the integer of 0-3. When i ²¹¹ is 0, it is a single bond. However, R ²¹⁵ and (CH ₂ ) _i CHR ²¹⁶ R ²¹⁷ are not the same.

In the above formula (108), R ^{221 to} R ²²⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. R ²²⁵ and R ²²⁶ each independently represent a substituted or unsubstituted alkyl group having 1 to 9 carbon atoms. However, R ²²⁵ and R ²²⁶ are not the same. i ²²¹ represents an integer of 0 to 3. When i ²²¹ is 0, it is a single bond.

  Examples of the bisphenol compound represented by the formulas (107) and (108) include 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 2,2-bis(4-hydroxyphenyl)-5-methylhexane, 3,3-bis(4-hydroxyphenyl)-5-methylheptane, 2,2-bis(4-hydroxyphenyl)-3-methylbutane, 1,1-bis(4-hydroxyphenyl)-1-phenyl-2 -Methylpropane, 1,1-bis(4-hydroxyphenyl)-1-phenyl-3-methylbutane, 2,2-bis(4-hydroxyphenyl)-6-methylheptane, 1,1-bis(4-hydroxy) Examples thereof include phenyl)-2-ethylhexane and 1,1-bis(4-hydroxyphenyl)-1-phenyl-2-methylpentane. It is also possible to use two or more of these in combination.

  (2) At least one bisphenol compound selected from formulas (110) to (112)

In formula (110), R ^{241 to} R ²⁴⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. X represents a single bond, an oxygen atom, a sulfur atom, or a sulfonyl group.

In formula (111), R ^{251 to} R ²⁵⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. R ^{256 to} R ²⁵⁷ each independently represent a hydrogen atom, an alkyl group, an aryl group or a halogenated alkyl group. The aryl group may be substituted with an alkyl group, an alkoxy group, or a halogen atom.

In formula (112), R ^{261 to} R ²⁶⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. W represents a cycloalkylidene group having 5 to 12 carbon atoms. The cycloalkylidene group may be substituted with an alkyl group.

  Examples of the bisphenol compound represented by the formulas (110) to (112) include 4,4'-dihydroxybiphenyl, 4,4'-dihydroxy-3,3'-dimethylbiphenyl and 4,4'-dihydroxy-2,2'. -Dimethylbiphenyl, 4,4'-dihydroxy-3,3',5-trimethylbiphenyl, 4,4'-dihydroxy-3,3',5,5'-tetramethylbiphenyl, 4,4'-dihydroxy-3 ,3'-dibutylbiphenyl, 4,4'-dihydroxy-3,3'-dicyclohexylbiphenyl, 3,3'-difluoro-4,4'-dihydroxybiphenyl, 4,4'-dihydroxy-3,3'-diphenyl Biphenyl, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(3-methyl-4-hydroxyphenyl)ethane, 1,1-bis(3-fluoro-4-hydroxyphenyl)ethane, 1 ,1-bis(2-tert-butyl-4-hydroxy-3-methylphenyl)ethane, 1,2-bis(4-hydroxyphenyl)ethane, 1,2-bis(3-methyl-4-hydroxyphenyl) Ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 2 ,2-bis(3-phenyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(3-fluoro-4-hydroxyphenyl) Propane, 2,2-bis(3-chloro-4-hydroxyphenyl)propane, 2,2-bis(3-bromo-4-hydroxyphenyl)propane, 2,2-bis(3,5-difluoro-4-) Hydroxyphenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(2 -Tert-butyl-4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 2,2-bis(3-methyl-4-hydroxyphenyl)hexafluoropropane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)hexafluoropropane, 2,2-bis(3-phenyl-4-hydroxyphenyl)hexafluoropropane, 2,2-bis(3-fluoro-) Four -Hydroxyphenyl)hexafluoropropane, 2,2-bis(3-chloro-4-hydroxyphenyl)hexafluoropropane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(3-methyl- 4-hydroxyphenyl)cyclohexane, 1,1-bis(3-cyclo-4-hydroxyphenyl)cyclohexane, 1,1-bis(3-phenyl-4-hydroxyphenyl)cyclohexane, 1,1-bis(3,5) -Dimethyl-4-hydroxyphenyl)cyclohexane, 1,1-bis(3-fluoro-4-hydroxyphenyl)cyclohexane, 1,1-bis(3-chloro-4-hydroxyphenyl)cyclohexane, 1,1-bis( 3-bromo-4-hydroxyphenyl)cyclohexane, 1,1-bis(3,5-difluoro-4-hydroxyphenyl)cyclohexane, 1,1-bis(3,5-dichloro-4-hydroxyphenyl)cyclohexane, 1 ,1-bis(3,5-dibromo-4-hydroxyphenyl)cyclohexane, 1,1-bis(2-tert-butyl-4-hydroxy-3-methylphenyl)cyclohexane, bis(4-hydroxyphenyl)sulfone, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)-1-phenyl Examples thereof include ethane, bis(4-hydroxyphenyl)diphenylmethane, 9,9-bis(4-hydroxyphenyl)-fluorene and 2,2-bis(4-hydroxyphenyl)butane. It is also possible to use two or more of these in combination.

(Structural unit selected from group A)
Among the structural units selected from Group A, it is preferable to use a polycarbonate resin having structural units represented by the following formulas (A-101) to (A-105) from the viewpoint of the fogging suppressing effect and the improvement of the electrical characteristics. .. By using a polycarbonate resin having such a structural unit, it is considered that in the charge transport layer, the distance between the resins and the distance between the resin and the charge transport substance become uniform, and the mechanical strength and electrical characteristics are improved. ..

  Among the structural units selected from the group A, it is preferable to use a polycarbonate resin having a structural unit represented by the following formulas (A-201) to (A-205) for the storage stability of the coating solution for the charge transport layer and the photo stability. It is preferable from the viewpoint of the effect of suppressing the memory and the improvement of the electrical characteristics during repeated use. It is considered that the use of the polycarbonate resin having such a structural unit improves the solubility of the resin in the solvent in the charge transport layer coating liquid. Further, in the charge transport layer, it is considered that the distance between the resin and the charge transport material becomes uniform and the electrical characteristics are improved. Here, the photo memory means that a carrier generated by exposing the electrophotographic photosensitive member to light such as a fluorescent lamp stays in the photosensitive layer during maintenance after repeated use of the process cartridge and the electrophotographic apparatus. This is a phenomenon that occurs. When an image is formed in this state, a potential difference is generated between a portion exposed to light and a portion not exposed to light, resulting in an image having uneven density.

  Among the structural units selected from the group A, it is preferable to use a polycarbonate resin having a structural unit represented by the following formulas (A-401) to (A-405) for the storage stability of the coating liquid for the charge transport layer, It is preferable from the viewpoint of improving the effect of suppressing the memory. It is considered that the use of the polycarbonate resin having such a structural unit improves the solubility of the resin in the solvent in the charge transport layer coating liquid.

(Structural unit selected from group B)
Among the structural units selected from the group B, it is preferable to use a polycarbonate resin having a structural unit represented by the following formulas (B-101) to (B-105) from the viewpoint of the fogging suppressing effect and electric characteristics. By using a polycarbonate resin having such a structural unit, it is considered that in the charge transport layer, the distance between the resins and the distance between the resin and the charge transport substance become uniform, and the mechanical strength and electrical characteristics are improved. ..

  Among the structural units selected from Group B, it is preferable to use a polycarbonate resin having structural units represented by the following formulas (B-201) to (B-205) from the viewpoint of the fogging suppressing effect. It is considered that the use of the polycarbonate resin having such a structural unit improves the mechanical strength because the resins are densely packed in the charge transport layer.

  Among the structural units selected from Group B, it is preferable to use a polycarbonate resin having a structural unit represented by the following formulas (B-301) to (B-308) for the storage stability of the coating liquid for the charge transport layer, It is preferable from the viewpoint of the effect of suppressing the memory and the improvement of the electric characteristics during repeated use. It is considered that the use of the polycarbonate resin having such a structural unit improves the solubility of the resin in the solvent in the charge transport layer coating liquid. Further, in the charge transport layer, it is considered that the distance between the resin and the charge transport material becomes uniform and the electrical characteristics are improved.

  Among the structural units selected from the group B, it is preferable to use a polycarbonate resin having a structural unit represented by the following formulas (B-401) to (B-405) for the storage stability of the coating solution for the charge transport layer, It is preferable from the viewpoint of the effect of suppressing the memory and the improvement of the electric characteristics during repeated use. It is considered that the use of the polycarbonate resin having such a structural unit improves the solubility of the resin in the solvent in the charge transport layer coating liquid. Further, in the charge transport layer, it is considered that the distance between the resin and the charge transport material becomes uniform and the electrical characteristics are improved.

  The content ratio of the structural unit selected from Group A in the polycarbonate resin is preferably 20 mol% or more and 70 mol% or less, and more preferably 25 mol% or more and 49 mol% or less.

  In the present invention, the weight average molecular weight (Mw) of the polycarbonate resin is preferably 30,000 or more and 100,000 or less, and more preferably 40,000 or more and 80,000 or less. When the weight average molecular weight of the polycarbonate resin is less than 30,000, the mechanical strength is low and the fogging suppressing effect may not be sufficiently obtained. On the other hand, if the weight average molecular weight of the polycarbonate resin is larger than 100,000, the storage stability of the charge transport layer coating solution may not be sufficiently obtained. In the examples described later, the weight average molecular weight of the resin was determined by gel permeation chromatography (GPC) [measuring instrument: Alliance HPLC system (manufactured by Waters)] using two Shodex KF-805L columns (manufactured by Showa Denko), 0. A 25 w/v% chloroform solution sample, 1 ml/min chloroform eluent, was measured under the condition of UV detection at 254 nm, and calculated as a polystyrene conversion value.

  The intrinsic viscosity of the polycarbonate resin is preferably 0.3 dL/g to 2.0 dL/g.

The relative permittivity ε of the polycarbonate resin can be obtained from the following Clausius-Mossotti equation.
K=(4π/3)×(α/V)
ε=(1+2K)/(1-K)
Here, V is the molecular volume in the stable structure obtained after the structure optimization calculation by the density functional calculation B3LYP/6-31G(d,p), and α is the limit in the stable structure obtained after the structure optimization calculation. It is the polarizability according to the Hartree-Fock method calculation (the basis function is 6-31G(d,p)). In the case of a polycarbonate resin having a plurality of structural units (for example, a copolymer), it is a value obtained by multiplying the relative permittivity of each structural unit by the content ratio and summing. For example, in the case of the exemplary compound 1001, the relative dielectric constant of the structural unit (A-101) is 2.12 and the relative dielectric constant of the structural unit (B-101) is 2.11. From this value, the relative dielectric constant can be calculated as 2.12 from the content ratio of the exemplary compound 1001. In the present invention, the relative permittivity ε is preferably 2.15 or less, and more preferably 2.13 or less.

  When the relative permittivity ε is 2.15 or less, high speed response is improved. The reason for this is presumed as follows. The high-speed responsiveness as used herein means that an image density equivalent to that obtained when an image is formed is obtained when a normal process speed and a case where the process speed is increased and used. Normally, when the process speed is changed, the amount of light received by the electrophotographic photosensitive member differs. At that time, even if the light amount is controlled so that the light amount received by the electrophotographic photosensitive member becomes equal, the image density may differ when the image is formed due to the difference in process speed. This density change becomes noticeable in a high-speed process because the interval between exposure and development becomes shorter as the process speed becomes faster. The cause of this is reciprocity law failure, and it was necessary to perform complicated control in order to obtain an equivalent image density. However, the present inventor believes that there are other causes besides reciprocity law failure. It is considered that this is because the light decay rate of the surface potential of the electrophotographic photosensitive member during development is different between the exposure and the development, which is a process that the electrophotographic photosensitive member undergoes during image formation. That is, it is considered that even if the surface potential is the same at the time of development, if the bright decay rate of the surface potential at the time of development is different, the developability of the toner is different, and the image density at the time of image formation changes. The charges generated in the charge generation layer are injected into the charge transport layer and transported to the surface of the electrophotographic photosensitive member in the charge transport layer. Some of the charges reach the surface of the electrophotographic photosensitive member in a short time, and some of the charges take a relatively long time to reach the surface of the electrophotographic photosensitive member (residual charge). Since the bright decay rate during development is immediately after the photo-response due to charging-exposure, it is considered that the carrier behavior of the residual charge at a low electric field strength in the charge transport layer has an influence. When the relative permittivity ε of the polycarbonate resin is 2.15 or less, it is considered that the change in discharge capability of the residual charge at a low electric field strength is small with time and the light decay rate at the time of development is small. When the relative permittivity ε of the polycarbonate resin is 2.15 or less, the toner developability does not change so much with respect to the potential unevenness on the surface of the electrophotographic photosensitive member, and the normal process speed and the process speed are used at a slower speed. The present inventor believes that the same image density can be obtained by performing image formation in some cases.

  When the relative permittivity ε of the polycarbonate resin is 2.15 or less, the electric field strength applied to the charge transport layer is advantageous to the charge transport ability of the charge transport layer and the injection ability from the charge generation layer to the charge transport layer. Therefore, it is considered to be excellent in suppressing the photo memory after repeated use.

<Specific examples of polycarbonate resin>
Tables 1 to 12 show specific examples of the polycarbonate resin having the structural unit selected from the group A and the structural unit selected from the group B, and the relative dielectric constant thereof.

<Polycarbonate resin synthesis method>
As an example, a method for synthesizing Exemplified Compound 1001 is shown below. Other polycarbonate resins can be synthesized by appropriately changing the types and addition amounts of the group A structural raw material and the group B structural raw material in the following (Synthesis Method of Exemplified Compound 1001). The weight average molecular weight of the resin can be adjusted by appropriately changing the addition amount of the molecular weight modifier.

(Synthesis Method of Exemplified Compound 1001)
53.0 g (0.196 mol) of 2,2-bis(4-hydroxyphenyl)-4-methylpentane (manufactured by Tokyo Kasei Kogyo, product code D3267) as a Group A structural raw material was added to 1100 ml of a 5 mass% aqueous sodium hydroxide solution. ), 41.2 g (0.204 mol) of bis(4-hydroxyphenyl)ether (manufactured by Tokyo Chemical Industry Co., Ltd., product code D2121) as a Group B structural raw material, and 0.1 g of hydrosulfite were dissolved. To this, 500 ml of methylene chloride was added, and while stirring and maintaining the temperature at 15° C., 60 g of phosgene was then blown in for 60 minutes.
After the completion of blowing phosgene, 1.3 g of p-t-butylphenol (manufactured by Tokyo Chemical Industry Co., Ltd., product code B0383) was added as a molecular weight modifier and stirred to emulsify the reaction solution. After emulsification, 0.4 ml of triethylamine was added, and the mixture was stirred at 23° C. for 1 hour for polymerization.
After the completion of the polymerization, the reaction solution was separated into an aqueous phase and an organic phase, the organic phase was neutralized with phosphoric acid, and the washing with water (aqueous phase) was repeatedly washed with water until the conductivity became 10 μS/cm or less. The obtained polymer solution was added dropwise to warm water kept at 45° C., and the solvent was removed by evaporation to obtain a white powdery precipitate. The obtained precipitate was filtered and dried at 110° C. for 24 hours to obtain a polycarbonate resin of Exemplified Compound 1001 including a copolymerization of A group structural unit A-101 and B group structural unit B-101.

The results of the obtained polycarbonate resin was analyzed by infrared absorption spectrum, absorption by carbonyl group at the position in the vicinity of 1770 cm ^-1, observed absorption by ether bond position near 1240 cm ^-1, it is polycarbonate resin is confirmed ..

[Electrophotographic photoreceptor]
The electrophotographic photosensitive member of the present invention has a support, a charge generation layer, and a charge transport layer which is a surface layer in this order. Other layers may be provided between the support and the charge transport layer. Hereinafter, each layer will be described.

  Examples of the method for producing the electrophotographic photosensitive member include a method in which a coating solution for each layer described below is prepared, coated in the order of desired layers, and dried. At this time, as a coating method of the coating liquid, a dip coating method (immersion coating method), a spray coating method, a curtain coating method, a spin coating method and the like can be mentioned. Among these, the dip coating method is preferable from the viewpoint of efficiency and productivity.

<Support>
In the present invention, the support is preferably a conductive support having conductivity. As the conductive support, for example, aluminum, iron, nickel, copper, a support formed of a metal or alloy such as gold, or polyester resin, polycarbonate resin, polyimide resin, on an insulating support such as glass, Examples thereof include thin films of metals such as aluminum, chromium, silver, and gold; thin films of conductive materials such as indium oxide, tin oxide, and zinc oxide; and supports having a thin film of conductive ink to which silver nanowires are added.

  The surface of the support may be subjected to an electrochemical treatment such as anodic oxidation, a wet honing treatment, a blast treatment, or a cutting treatment in order to improve electric characteristics and suppress interference fringes.

  Examples of the shape of the support include a cylindrical shape and a film shape.

<Conductive layer>
In the present invention, a conductive layer may be provided on the support. By providing the conductive layer, it becomes possible to cover unevenness and defects of the support and prevent interference fringes. The average film thickness of the conductive layer is preferably 5 μm or more and 40 μm or less, and more preferably 10 μm or more and 30 μm or less.

  The conductive layer preferably contains conductive particles and a binder resin. Examples of the conductive particles include carbon black, metal particles and metal oxide particles.

  As the metal oxide particles, for example, zinc oxide, lead white, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, bismuth oxide, indium oxide doped with tin, antimony. Examples thereof include tin oxide particles doped with tantalum. You may use together 2 or more types of these. Among these, particles of zinc oxide, tin oxide and titanium oxide are preferable. In particular, titanium oxide particles are preferable from the viewpoint of high sensitivity, since they hardly absorb visible light and near infrared light and are white. Examples of the crystal type of titanium oxide include rutile type, anatase type, brookite type, and amorphous type, and any crystal type may be used. Further, titanium oxide particles having needle crystals or granular crystals may be used. More preferably, the particles are rutile-type titanium oxide crystals. The number-based average primary particle diameter of the metal oxide particles is preferably 0.05 to 1 μm, and more preferably 0.1 to 0.5 μm.

  Examples of the binder resin include phenol resin, polyurethane resin, polyamide resin, polyimide resin, polyamideimide resin, polyvinyl acetal resin, epoxy resin, acrylic resin, melamine resin, and polyester resin. You may use together 2 or more types of these. Among these, a curable resin is preferable from the viewpoint of resistance to a solvent in a coating liquid used for forming another layer, adhesion to a conductive support, and dispersibility/dispersion stability of metal oxide particles. More preferably, it is a thermosetting resin. Examples of the thermosetting resin include thermosetting phenol resin and thermosetting polyurethane resin.

<Undercoat layer>
In the present invention, an undercoat layer may be provided on the support or the conductive layer. The barrier function and the adhesive function are enhanced by providing the undercoat layer. The average film thickness of the undercoat layer is preferably 0.3 μm or more and 5.0 μm or less.

  The undercoat layer preferably contains an electron-transporting substance or metal oxide particles and a binder resin. With such a configuration, among the charges generated in the charge generation layer, electrons can be transported to the support, so even if the charge transportability of the charge transport layer is improved, deactivation of the charge in the charge generation layer, The increase in traps can be suppressed. Therefore, the initial electrical characteristics and the electrical characteristics during repeated use are improved.

  Examples of the electron transport material include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, naphthylimide compounds, and peryleneimide compounds. The electron transport material preferably has a polymerizable functional group such as a hydroxy group, a thiol group, an amino group, a carboxyl group and a methoxy group.

  The metal oxide particles and the binder resin are the same as those described in the conductive layer.

<Charge generation layer>
In the present invention, the charge generation layer is provided between the support and the charge transport layer. The charge generation layer is preferably adjacent to the charge transport layer. The thickness of the charge generation layer is preferably 0.05 μm or more and 1 μm or less, and more preferably 0.1 μm or more and 0.3 μm or less.

  In the present invention, the charge generation layer preferably contains a charge generation substance and a binder resin.

  The content of the charge generating substance in the charge generating layer is preferably 40% by mass or more and 85% by mass or less, and more preferably 60% by mass or more and 80% by mass or less.

  Examples of the charge generating substance include azo pigments such as monoazo, disazo and trisazo, phthalocyanine pigments such as metal phthalocyanine and non-metal phthalocyanine; indigo pigments; perylene pigments; polycyclic quinone pigments; squarylium dyes; thiapyrylium salts; triphenylmethane dyes; Examples include quinacridone pigments, azurenium salt pigments, cyanine dyes, xanthene dyes, quinoneimine dyes, and styryl dyes. Among these, phthalocyanine pigments are preferable, and gallium phthalocyanine crystals are more preferable.

  Among the gallium phthalocyanine crystals, hydroxygallium phthalocyanine crystals, chlorogallium phthalocyanine crystals, bromogallium phthalocyanine crystals, and iodogallium phthalocyanine crystals having excellent sensitivity are preferable. Of these, hydroxygallium phthalocyanine crystals and chlorogallium phthalocyanine crystals are particularly preferable. The hydroxygallium phthalocyanine crystal is one in which a gallium atom has a hydroxy group as an axial ligand. In the chlorogallium phthalocyanine crystal, the gallium atom has a chlorine atom as an axial ligand. In the bromogallium phthalocyanine crystal, a gallium atom has a bromine atom as an axial ligand. In the iodogallium phthalocyanine crystal, a gallium atom has an iodine atom as an axial ligand. From the viewpoint of improving sensitivity, a hydroxygallium phthalocyanine crystal having peaks at 7.4°±0.3° and 28.3°±0.3° at a Bragg angle 2θ in X-ray diffraction of CuKα ray, and X of CuKα ray. A chlorogallium phthalocyanine crystal having peaks at 7.4°, 16.6°, 25.5° and 28.3° at a Bragg angle 2θ±0.2° in line diffraction is more preferable.

  Further, the gallium phthalocyanine crystal is preferably a gallium phthalocyanine crystal containing an amide compound represented by the following formula in the crystal.

(In the above formula, R ⁸¹ represents a methyl group, a propyl group, or a vinyl group.)
Specific examples include N-methylformamide, N-propylformamide and N-vinylformamide.

The content of the amide compound is preferably 0.1% by mass or more and 1.9% by mass or less, and 0.3% by mass or more and 1.5% by mass or less, based on the gallium phthalocyanine in the gallium phthalocyanine crystal. Is more preferable. When the content of the amide compound is 0.1% by mass or more and 1.9% by mass or less, it is considered that the dark current from the charge generation layer when the electric field strength is high becomes small, and The fogging suppressing effect of the charge transport layer can be further enhanced. The content of the amide compound can be measured by the ¹ H-NMR method.

  The gallium phthalocyanine crystal containing the amide compound in the crystal is obtained by a step of wet milling a crystal containing gallium phthalocyanine treated by an acid pasting method or dry milling and a solvent containing the amide compound for crystal conversion.

  The wet milling treatment is a treatment performed using a milling device such as a sand mill or a ball mill together with a dispersant such as glass beads, steel beads or alumina balls.

  Examples of the binder resin include resins such as polyester, acrylic resin, polycarbonate, polyvinyl butyral, polystyrene, polyvinyl acetate, polysulfone, acrylonitrile copolymer, and polyvinyl benzal. Among these, polyvinyl butyral and polyvinyl benzal are preferable as the resin in which the gallium phthalocyanine crystal is dispersed.

<Charge transport layer>
In the present invention, the charge transport layer contains a charge transport substance and a polycarbonate resin having a structural unit selected from the group A and a structural unit selected from the group B. Further, a release agent is included for the purpose of increasing the transfer efficiency of the toner, an anti-fingerprint agent for the purpose of suppressing stains, a filler for the purpose of suppressing abrasion, and a lubricant for the purpose of improving lubricity. May be.

  In the present invention, the charge transport layer is prepared by mixing a charge transport material and a polycarbonate resin with a solvent to prepare a coating solution for the charge transport layer, forming a coating film of the coating solution for the charge transport layer, and drying the coating film. Can be formed with.

  As the solvent used for the charge transport layer coating solution, ketone solvents such as acetone and methyl ethyl ketone; ester solvents such as methyl acetate and ethyl acetate; aromatic hydrocarbon solvents such as toluene, xylene and chlorobenzene; 1,4-dioxane , An ether solvent such as tetrahydrofuran; a hydrocarbon solvent such as chloroform substituted with a halogen atom, and the like. These may be used in combination of two or more. Above all, a solvent having a dipole moment of 1.0 D or less is preferable. Examples of the solvent having a dipole moment of 1.0 D or less include o-xylene (dipole moment=0.64D) and methylal (dimethoxymethane) (dipole moment=0.91D).

  The thickness of the charge transport layer is preferably 5 μm or more and 40 μm or less, and more preferably 7 μm or more and 25 μm or less.

  The content of the charge-transporting substance in the charge-transporting layer is preferably 20% by mass or more and 80% by mass or less, and 40% by mass from the viewpoint of the fogging suppressing effect of the electrophotographic photoreceptor and the improvement of long-term storage stability. It is more preferably 70% by mass or less.

  The molecular weight of the charge transport material is preferably 300 or more and 1,000 or less. From the viewpoint of improving electric characteristics and long-term storage stability during repeated use, 600 or more and 800 or less are more preferable. Further, from the viewpoint of the effect of suppressing the photo memory and the improvement of long-term storage stability, 350 or more and 600 or less are more preferable.

  Examples of the charge transport material include triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds and triallylmethane compounds. You may use together 2 or more types of these. Among these, it is preferable to use the triarylamine compound. Hereinafter, as specific examples of the charge transport material, general formulas and exemplified compounds satisfying the general formulas will be shown.

(In the above formula, Ar ¹⁰¹ and Ar ¹⁰² each independently represent an aryl group which may have a substituent, and R ¹⁰¹ and R ¹⁰² each independently represent a hydrogen atom, an alkyl group or a substituent. Represents a good aryl group. The substituent of the substituted aryl group is an alkyl group, an alkoxy group or a halogen atom.)
Hereinafter, exemplary compounds of (CTM-1) will be shown.

(In the above formula, Ar ^{103 to} Ar ¹⁰⁶ each independently represent an aryl group which may have a substituent, Z ¹⁰¹ represents an arylene group which may have a substituent, or a plurality of arylene groups are vinylene groups. A divalent group bonded via R. The two adjacent substituents on Ar ^{103 to} Ar ¹⁰⁶ may be bonded to each other to form a ring. Is an alkyl group, an alkoxy group, or a halogen atom.)
Hereinafter, exemplary compounds of (CTM-2) will be shown.

(In the above formula, R ¹⁰³ represents an alkyl group, a cycloalkyl group or an aryl group which may have a substituent, and R ¹⁰⁴ represents a hydrogen atom, an alkyl group or an aryl group which may have a substituent. In the formula, Ar ¹⁰⁷ represents an aryl group which may have a substituent, Z ¹⁰² represents an arylene group which may have a substituent, n ¹⁰¹ represents 1 to 3, and m represents an integer of 0 to 2. , M+n ¹⁰¹ =3, and when m is 2, R ¹⁰³ may be the same or different, and two adjacent substituents on R ¹⁰³ may be bonded to each other to form a ring. ¹⁰³ and Z ¹⁰² may be bonded to each other to form a ring, and Ar ¹⁰⁷ and R ¹⁰⁴ may be bonded to each other via a vinylene group to form a ring. The substituent of is an alkyl group, an alkoxy group, or a halogen atom.)
Hereinafter, exemplary compounds of (CTM-3) will be shown.

(In the above formula, Ar ^{108 to} Ar ¹¹¹ each independently represents an aryl group which may have a substituent. The substituent of the substituted aryl group is an alkyl group, an alkoxy group, a halogen atom or 4-phenyl- Buta-1,3-dienyl group.)
Hereinafter, exemplary compounds of (CTM-4) will be shown.

(In the above formula, Ar ^{112 to} Ar ¹¹⁷ each independently represent an aryl group which may have a substituent, and Z ¹⁰³ is a phenylene group, a biphenylene group, or two phenylene groups bonded to each other through an alkylene group. A divalent group is shown. The substituent of the substituted aryl group is an alkyl group, an alkoxy group, or a halogen atom.)
Hereinafter, exemplary compounds of (CTM-5) will be shown.

(In the above formula, at least one of R ^{105 to} R ¹⁰⁸ is a monovalent group represented by the following formula, and the rest are each independently an alkyl group or an aryl group which may have a substituent. , Z ¹⁰⁴ represents an arylene group which may have a substituent, or a divalent group in which a plurality of arylene groups are bonded via a vinylene group, and n ¹⁰² represents 0 or 1. The substituted aryl group, The substituent of the arylene group is an alkyl group, an alkoxy group, or a halogen atom.)

(In the above formula, R ¹⁰⁹ and R ¹¹⁰ each independently represent a hydrogen atom, an alkyl group, or an aryl group which may have a substituent, and Ar ¹¹⁸ represents an aryl group which may have a substituent. Z ¹⁰⁵ represents an arylene group which may have a substituent, n ₂ represents an integer of 1 to _{3. The} substituent of the substituted aryl group is an alkyl group, an alkoxy group, a dialkylamino group or a diarylamino group. The substituent of the substituted arylene group is an alkyl group, an alkoxy group, or a halogen atom.)
Hereinafter, exemplary compounds of (CTM-6) will be shown.

(In the above formula, Ar ¹¹⁹ represents an aryl group which may have a substituent, a monovalent group represented by formula (7-1) or formula (7-2), and Ar ¹²⁰ and Ar ¹²¹ each independently. Represents an aryl group which may have a substituent. The substituent of the substituted aryl group is an alkyl group, an alkoxy group or a halogen atom.)

(In the above formula, Ar ¹²² and Ar ¹²³ each independently represent an aryl group which may have a substituent or an aralkyl group which may have a substituent. The substituted aryl group and the substituent of the aralkyl group Is an alkyl group, an alkoxy group, or a halogen atom.)

(In the above formula, R ¹¹¹ and R ¹¹² each independently represent an aryl group which may have a substituent, and Z ¹⁰⁶ represents an arylene group which may have a substituent. The substituted aryl group and arylene The substituent of the group is an alkyl group, an alkoxy group or a halogen atom.)
Hereinafter, exemplary compounds of (CTM-7) will be shown.

[Process cartridge, electrophotographic device]
FIG. 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

  Reference numeral 1 denotes a cylindrical (drum-shaped) electrophotographic photosensitive member, which is rotationally driven around a shaft 2 in a direction of an arrow at a predetermined peripheral speed (process speed). The surface of the electrophotographic photosensitive member 1 is charged to a predetermined positive or negative potential by the charging unit 3 during the rotation process. Then, the charged surface of the electrophotographic photosensitive member 1 is irradiated with the exposure light 4 from the exposing means (not shown), and an electrostatic latent image corresponding to the target image information is formed. The exposure light 4 is, for example, light intensity-modulated corresponding to a time-series electric digital image signal of target image information, which is output from an image exposure means such as slit exposure or laser beam scanning exposure.

  The electrostatic latent image formed on the surface of the electrophotographic photosensitive member 1 is developed (normal development or reversal development) with the toner contained in the developing unit 5, and a toner image is formed on the surface of the electrophotographic photosensitive member 1. To be done. The toner image formed on the surface of the electrophotographic photosensitive member 1 is transferred to the transfer material 7 by the transfer unit 6. At this time, a bias voltage having a polarity opposite to the charge held by the toner is applied to the transfer unit 6 from a bias power source (not shown). Further, when the transfer material 7 is paper, the transfer material 7 is taken out from the paper feeding section (not shown) and is synchronized between the electrophotographic photosensitive member 1 and the transfer means 6 in synchronization with the rotation of the electrophotographic photosensitive member 1. Will be delivered.

  The transfer material 7 onto which the toner image has been transferred from the electrophotographic photosensitive member 1 is separated from the surface of the electrophotographic photosensitive member 1 and conveyed to the fixing unit 8 to undergo a fixing process of the toner image, thereby forming an image-formed product. (Print, copy) is printed out of the electrophotographic apparatus.

  The surface of the electrophotographic photosensitive member 1 after the toner image is transferred onto the transfer material 7 is cleaned by the cleaning means 9 after removing adhering substances such as toner (transfer residual toner). In recent years, a cleanerless system has also been developed, and it is possible to directly remove transfer residual toner by a developing device or the like. Further, the surface of the electrophotographic photosensitive member 1 is subjected to charge elimination processing by pre-exposure light 10 from a pre-exposure means (not shown), and then repeatedly used for image formation. If the charging means 3 is a contact charging means using a charging roller or the like, the pre-exposure means is not always necessary.

  In the present invention, among the components such as the electrophotographic photoreceptor 1, the charging unit 3, the developing unit 5, the transfer unit 6 and the cleaning unit 9 described above, a plurality of components are housed in a container and integrally supported to perform the process. A cartridge may be formed. The process cartridge can be detachably attached to the main body of the electrophotographic apparatus. For example, at least one selected from the charging unit 3, the developing unit 5, and the cleaning unit 9 is integrally supported with the electrophotographic photosensitive member 1 to form a cartridge. Then, by using the guide means 12 such as a rail of the electrophotographic apparatus main body, the process cartridge 11 can be detachably attached to the electrophotographic apparatus main body.

  The exposure light 4 may be reflected light or transmitted light from a document when the electrophotographic apparatus is a copying machine or a printer. Alternatively, it may be light emitted by scanning a document with a sensor, converting it into a signal, scanning a laser beam according to this signal, driving an LED array, driving a liquid crystal shutter array, or the like.

  The electrophotographic photoreceptor 1 of the present invention can be widely applied to electrophotographic application fields such as a laser beam printer, a CRT printer, an LED printer, a FAX, a liquid crystal printer and a laser plate making.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples unless it exceeds the gist. In the description of the following examples, “part” is based on mass unless otherwise specified.

<Synthesis of polycarbonate resin>
A polycarbonate resin was synthesized as follows. Table 13 shows the content ratio (mol%) of each structural unit and the weight average molecular weight.

[Polycarbonate Synthesis Example 1]
5,100 g of 2,2-bis(4-hydroxyphenyl)-4-methylpentane (hereinafter abbreviated as BPMP: manufactured by Tokyo Chemical Industry Co., Ltd., product code D3267) was added to 1100 ml of a 5 mass% sodium hydroxide aqueous solution. 196 mol), 41.2 g (0.204 mol) of bis(4-hydroxyphenyl)ether (hereinafter abbreviated as DHPE: manufactured by Tokyo Chemical Industry Co., Ltd., product code D2121), and 0.1 g of hydrosulfite were dissolved. To this, 500 ml of methylene chloride was added, and while stirring and maintaining the temperature at 15° C., 60 g of phosgene was blown in over 60 minutes.

  After the completion of phosgene blowing, 1.3 g of p-t-butylphenol (hereinafter, abbreviated as "PTBP": product code B0383 manufactured by Tokyo Kasei Kogyo Co., Ltd.) as a molecular weight modifier was added and stirred to emulsify the reaction solution. .. After emulsification, 0.4 ml of triethylamine was added, and the mixture was stirred at 23° C. for 1 hour for polymerization.

  After the completion of the polymerization, the reaction solution was separated into an aqueous phase and an organic phase, the organic phase was neutralized with phosphoric acid, and the washing with water (aqueous phase) was repeatedly washed with water until the conductivity became 10 μS/cm or less. The obtained polymer solution was added dropwise to warm water kept at 45° C., and the solvent was removed by evaporation to obtain a white powdery precipitate. The obtained precipitate is filtered, dried at 110° C. for 24 hours, and a polycarbonate resin (PC-1) having a structural unit represented by the formula (A-101) and a structural unit represented by the formula (B-101). Got

When the molecular weight of this polycarbonate resin was measured by GPC, it was Mw=63000. The results of the obtained polycarbonate resin was analyzed by infrared absorption spectrum, absorption by carbonyl group at the position in the vicinity of 1770 cm ^-1, observed absorption by ether bond position near 1240 cm ^-1, it is polycarbonate resin is confirmed ..

[Polycarbonate Synthesis Example 2]
A polycarbonate resin (PC-2) having Mw=78000 was obtained in the same manner as in Synthesis Example 1 of polycarbonate except that the addition amount of the molecular weight modifier: PTBP was changed to 1.0 g.

[Polycarbonate Synthesis Example 3]
A polycarbonate resin (PC-3) having Mw=50,000 was obtained in the same manner as in Synthesis Example 1 of polycarbonate except that the addition amount of the molecular weight modifier: PTBP was changed to 1.7 g.

[Polycarbonate Synthesis Example 4]
A polycarbonate resin (PC-4) having Mw=72000 was obtained in the same manner as in Synthesis Example 1 of polycarbonate except that the addition amount of the molecular weight modifier: PTBP was changed to 1.1 g.

[Polycarbonate Synthesis Example 5]
A polycarbonate resin (PC-5) having Mw=34000 was obtained in the same manner as in Synthesis Example 1 of polycarbonate except that the addition amount of the molecular weight modifier: PTBP was changed to 2.7 g.

[Polycarbonate Synthesis Example 6]
A polycarbonate resin (PC-6) having Mw=94000 was obtained in the same manner as in Synthesis Example 1 of polycarbonate except that the addition amount of the molecular weight modifier: PTBP was changed to 0.8 g.

[Polycarbonate Synthesis Example 7]
The same procedure as in Synthesis Example 1 of Polycarbonate was performed except that the amount of BPMP added was changed to 43.3 g, the amount of DHPE added was changed to 48.5 g, and the amount of the molecular weight modifier: PTBP was changed to 1.4 g. To obtain a polycarbonate resin (PC-7).

[Polycarbonate Synthesis Example 8]
The same procedure as in Polycarbonate Synthesis Example 1 was repeated except that the amount of BPMP added was 27.0 g, the amount of DHPE added was 60.6 g, and the amount of the molecular weight regulator: PTBP was changed to 1.6 g. Mw=53000 Polycarbonate resin (PC-8) was obtained.

[Polycarbonate Synthesis Example 9]
The same procedure as in Polycarbonate Synthesis Example 1 was repeated except that the amount of BPMP added was changed to 21.6 g, the amount of DHPE added was 64.7 g, and the amount of the molecular weight modifier: PTBP was changed to 1.6 g. Mw=52000 Polycarbonate resin (PC-9) was obtained.

[Polycarbonate Synthesis Example 10]
The same procedure as in Synthesis Example 1 of Polycarbonate except that the amount of BPMP added was changed to 75.7 g, the amount of DHPE added was changed to 24.3 g, and the added amount of a molecular weight modifier: PTBP was changed to 1.0 g, Mw=79000 Polycarbonate resin (PC-10) was obtained.

[Polycarbonate Synthesis Example 11]
DHPE was changed to 38.0 g of 4,4'-dihydroxybiphenyl (manufactured by Tokyo Kasei Kogyo Co., Ltd., product code B0464), and the same procedure as in Synthesis Example 1 of Polycarbonate was conducted. ) Got. This polycarbonate resin has a structural unit represented by the formula (A-101) and a structural unit represented by the formula (B-201).

[Polycarbonate Synthesis Example 12]
Molecular weight modifier: A polycarbonate resin (PC-12) having Mw=75000 was obtained in the same manner as in Polycarbonate Synthesis Example 11 except that the addition amount of PTBP was changed to 1.0 g.

[Polycarbonate Synthesis Example 13]
Molecular weight modifier: A polycarbonate resin (PC-13) having Mw=50,000 was obtained in the same manner as in Synthesis Example 11 of polycarbonate except that the addition amount of PTBP was changed to 1.6 g.

[Polycarbonate Synthesis Example 14]
A polycarbonate resin (PC-14) having an Mw of 69000 was obtained in the same manner as in Polycarbonate Synthesis Example 11, except that the addition amount of the molecular weight modifier: PTBP was changed to 1.1 g.

[Polycarbonate Synthesis Example 15]
A polycarbonate resin (PC-15) having Mw=33000 was obtained in the same manner as in Polycarbonate Synthesis Example 11 except that the addition amount of the molecular weight modifier: PTBP was changed to 2.7 g.

[Polycarbonate Synthesis Example 16]
Molecular weight modifier: A polycarbonate resin (PC-16) having Mw=91000 was obtained in the same manner as in Polycarbonate Synthesis Example 11 except that the addition amount of PTBP was changed to 0.8 g.

[Polycarbonate Synthesis Example 17]
Same as Synthesis Example 11 of Polycarbonate except that the addition amount of BPMP was changed to 43.3 g, the addition amount of 4,4′-dihydroxybiphenyl was changed to 44.7 g, and the addition amount of the molecular weight modifier: PTBP was changed to 1.2 g. Then, a polycarbonate resin (PC-17) having Mw=65000 was obtained.

[Polycarbonate Synthesis Example 18]
Same as Synthesis Example 11 of Polycarbonate except that the addition amount of BPMP was changed to 27.0 g, the addition amount of 4,4′-dihydroxybiphenyl was changed to 55.9 g, and the addition amount of a molecular weight modifier: PTBP was changed to 1.5 g. Then, a polycarbonate resin (PC-18) having Mw=54000 was obtained.

[Polycarbonate Synthesis Example 19]
Same as Synthesis Example 11 of Polycarbonate except that the addition amount of BPMP was changed to 21.6 g, the addition amount of 4,4′-dihydroxybiphenyl was changed to 59.7 g, and the addition amount of a molecular weight regulator: PTBP was changed to 1.6 g. Then, a polycarbonate resin (PC-19) having Mw=50,000 was obtained.

[Polycarbonate Synthesis Example 20]
Similar to Synthesis Example 11 of Polycarbonate except that the addition amount of BPMP was changed to 75.7 g, the addition amount of 4,4′-dihydroxybiphenyl was changed to 22.4 g, and the addition amount of the molecular weight modifier: PTBP was changed to 1.0 g. Then, a polycarbonate resin (PC-20) having Mw=75000 was obtained.

[Polycarbonate Synthesis Example 21]
The same procedure as in Synthesis Example 1 of Polycarbonate except that DHPE was changed to 52.3 g of 2,2-bis(3-methyl-4-hydroxyphenyl)propane (hereinafter abbreviated as BPC: manufactured by Honshu Chemical Industry Co., Ltd.), A polycarbonate resin (PC-21) having an Mw of 64000 was obtained. This polycarbonate resin has a structural unit represented by the formula (A-101) and a structural unit represented by the formula (B-307).

[Polycarbonate Synthesis Example 22]
Molecular weight modifier: A polycarbonate resin (PC-22) with Mw=80,000 was obtained in the same manner as in Polycarbonate Synthesis Example 21, except that the addition amount of PTBP was changed to 1.0 g.

[Polycarbonate Synthesis Example 23]
A polycarbonate resin (PC-23) having Mw=54000 was obtained in the same manner as in Polycarbonate Synthesis Example 21, except that the addition amount of the molecular weight modifier: PTBP was changed to 1.6 g.

[Polycarbonate Synthesis Example 24]
Molecular weight modifier: A polycarbonate resin (PC-24) with Mw=74000 was obtained in the same manner as in Polycarbonate Synthesis Example 21, except that the addition amount of PTBP was changed to 1.1 g.

[Polycarbonate Synthesis Example 25]
A polycarbonate resin (PC-25) having Mw of 35000 was obtained in the same manner as in Synthesis Example 21 of polycarbonate except that the addition amount of the molecular weight modifier: PTBP was changed to 2.7 g.

[Polycarbonate Synthesis Example 26]
A polycarbonate resin (PC-26) having Mw=96000 was obtained in the same manner as in Polycarbonate Synthesis Example 21, except that the addition amount of the molecular weight modifier: PTBP was changed to 0.8 g.

[Polycarbonate Synthesis Example 27]
The same procedure was performed as in Polycarbonate Synthesis Example 21 except that the amount of BPMP added was 43.3 g, the amount of BPC added was 61.5 g, and the amount of the molecular weight regulator: PTBP was changed to 1.2 g. Mw=69000 Polycarbonate resin (PC-27) was obtained.

[Polycarbonate Synthesis Example 28]
The same procedure was performed as in Synthesis Example 21 of Polycarbonate except that the amount of BPMP added was changed to 27.0 g, the amount of BPC added was 76.9 g, and the amount of the molecular weight modifier: PTBP was changed to 1.5 g. Mw=57,000 Polycarbonate resin (PC-28) was obtained.

[Polycarbonate Synthesis Example 29]
The same procedure was performed as in Synthesis Example 21 of Polycarbonate except that the addition amount of BPMP was changed to 21.6 g, the addition amount of BPC was changed to 82.0 g, and the addition amount of the molecular weight modifier: PTBP was changed to 1.6 g. =54000 polycarbonate resin (PC-29) was obtained.

[Polycarbonate Synthesis Example 30]
The same procedure as in Synthesis Example 21 of Polycarbonate was performed except that the amount of BPMP added was changed to 75.7 g, the amount of BPC added was changed to 30.8 g, and the added amount of a molecular weight modifier: PTBP was changed to 1.0 g. Polycarbonate resin (PC-30) was obtained.

[Polycarbonate Synthesis Example 31]
BPMP was changed to 55.7 g of 2,2-bis(4-hydroxyphenyl)-5-methylhexane obtained by deriving 5-methyl-2-hexanone (manufactured by Tokyo Chemical Industry Co., Ltd., product code I0087). Otherwise in the same manner as in Polycarbonate Synthesis Example 1, a polycarbonate resin (PC-31) having Mw=66000 was obtained. This polycarbonate resin has a structural unit represented by the formula (A-102) and a structural unit represented by the formula (B-101).

[Polycarbonate Synthesis Example 32]
BPMP was changed to 57.31 g of 3,3-bis(4-hydroxyphenyl)-5-methylheptane obtained by deriving 5-methyl-3-heptanone (manufactured by Tokyo Chemical Industry Co., Ltd., product code M0335). Otherwise in the same manner as in Polycarbonate Synthesis Example 1, a polycarbonate resin (PC-32) having Mw=68000 was obtained. This polycarbonate resin has a structural unit represented by the formula (A-201) and a structural unit represented by the formula (B-101).

[Polycarbonate Synthesis Example 33]
BPMP was changed to 65.2 g of 1,1-bis(4-hydroxyphenyl)-1-phenyl-3-methylbutane obtained by deriving BPMP from isobutylphenyl ketone (manufactured by Tokyo Chemical Industry Co., Ltd., product code I0296). Otherwise in the same manner as in Polycarbonate Synthesis Example 1, a polycarbonate resin (PC-33) having Mw=77,000 was obtained. This polycarbonate resin has a structural unit represented by the formula (A-103) and a structural unit represented by the formula (B-101).

[Comparative Synthesis Example 1 of Polycarbonate]
Polycarbonate with Mw=65000, except that BPMP was changed to 56.9 g of 1,1-bis(4-hydroxyphenyl)-1-phenylethane (manufactured by Honshu Chemical Industry Co., Ltd.). A resin (abbreviated as PC-34) was obtained. This polycarbonate resin has a structural unit represented by the following formula (comparative structure) and a structural unit represented by the formula (B-101).

[Comparative Synthesis Example 2 of Polycarbonate]
A polycarbonate resin (PC-35) was obtained in the same manner as in Polycarbonate Synthesis Example 1 except that BPMP was not used and 80.8 g of DHPE was added. This polycarbonate resin has a structural unit represented by the formula (B-101).

<Synthesis of gallium phthalocyanine crystal>
A gallium phthalocyanine crystal used as a charge generating substance was synthesized as follows.

(Synthesis of hydroxygallium phthalocyanine Ga-0)
Under an atmosphere of nitrogen flow, 5.46 parts of phthalonitrile and 45 parts of α-chloronaphthalene were charged into a reaction kettle, heated, and heated to a temperature of 30° C., and then this temperature was maintained. Next, 3.75 parts of gallium trichloride was added at this temperature (30° C.). The water content of the mixed solution at the time of addition was 150 ppm. Then, the temperature was raised to 200°C. Next, the mixture was reacted at a temperature of 200° C. for 4.5 hours under a nitrogen flow atmosphere, cooled, and when the temperature of 150° C. was reached, the product was filtered. The obtained filtered product was dispersed and washed with N,N-dimethylformamide at a temperature of 140° C. for 2 hours and then filtered. The obtained filtered product was washed with methanol and then dried to obtain 4.65 parts (yield 71%) of chlorogallium phthalocyanine (ClGa).

  4.65 parts of ClGa obtained above was dissolved in 139.5 parts of concentrated sulfuric acid at a temperature of 10° C., added dropwise to 620 parts of ice water under stirring to reprecipitate, and filtered using a filter press. The obtained wet cake (filtrate) was dispersed and washed with 2% ammonia water, and then filtered using a filter press. Then, the obtained wet cake (filtrate) is dispersed and washed with ion-exchanged water, and the filtration treatment using a filter press is repeated three times to obtain a hydroxygallium phthalocyanine pigment (hydrous gallium hydrate containing 23% solids). Phthalocyanine pigment) was obtained.

  6.6 kg of the obtained hydroxygallium phthalocyanine pigment (hydrous gallium phthalocyanine pigment) was dried as follows using a hyper dry dryer HD-06R (manufactured by Nippon Biocon, frequency (oscillation frequency): 2455 MHz±15 MHz). It was

  The obtained hydroxygallium phthalocyanine pigment was placed on a dedicated circular plastic tray in a lump state (water cake thickness of 4 cm or less) as it was taken out from the filter press, far infrared rays were turned off, and the temperature of the inner wall of the dryer was 50°C. Was set. Then, at the time of microwave irradiation, the vacuum pump and the leak valve were adjusted to adjust the degree of vacuum to 4.0 to 10.0 kPa.

  First, as the first step, the hydroxygallium phthalocyanine pigment was irradiated with microwaves of 4.8 kW for 50 minutes, and then the microwave was once cut off and the leak valve was once closed to obtain a high vacuum of 2 kPa or less. The solid content of the hydroxygallium phthalocyanine pigment at this point was 88%. In the second step, the leak valve was adjusted and the degree of vacuum (pressure in the dryer) was adjusted to be within the set value (4.0 to 10.0 kPa). Then, the hydroxygallium phthalocyanine pigment was irradiated with a microwave of 1.2 kW for 5 minutes, and the microwave was once cut off and the leak valve was once closed to create a high vacuum of 2 kPa or less. This second step was repeated once more (two times in total). The solid content of the hydroxygallium phthalocyanine pigment at this point was 98%. As the third step, microwave irradiation was performed in the same manner as in the second step except that the microwave in the second step was changed from 1.2 kW to 0.8 kW. This third step was repeated once more (two times in total). In the fourth step, the leak valve was adjusted to restore the vacuum degree (pressure inside the dryer) to within the set value (4.0 to 10.0 kPa). Thereafter, the hydroxygallium phthalocyanine pigment was irradiated with a microwave of 0.4 kW for 3 minutes, and the microwave was once cut off and the leak valve was once closed to create a high vacuum of 2 kPa or less. This fourth step was repeated 7 more times (8 times in total). As described above, 1.52 kg of hydroxygallium phthalocyanine (Ga-0) having a water content of 1% or less was obtained in a total of 3 hours.

(Synthesis of gallium phthalocyanine crystal Ga-1)
0.5 parts of the hydroxygallium phthalocyanine Ga-0 obtained above and 10 parts of N-methylformamide were milled together with 20 parts of glass beads having a diameter of 0.8 mm in a ball mill at room temperature (23° C.) under the condition of 120 rpm. It went for 300 hours. From this dispersion, gallium phthalocyanine crystals were taken out using N,N-dimethylformamide, filtered, and the filter was thoroughly washed with tetrahydrofuran. The filtered material was vacuum dried to obtain 0.45 part of hydroxygallium phthalocyanine crystal Ga-1. The powder X-ray diffraction pattern of the obtained crystals is shown in FIG.

In addition, 0.9 mass% of N-methylformamide is contained in the Ga-1 crystal by ¹ H-NMR method [measuring instrument: AVANCEIII 500 (manufactured by BRUKER)] using bisulfate as a solvent. confirmed.

(Synthesis of gallium phthalocyanine crystal Ga-2)
In the above (synthesis of gallium phthalocyanine crystal Ga-1), hydroxygallium was similarly prepared except that 10 parts of N-methylformamide was changed to 10 parts of N,N-dimethylformamide and the milling treatment time was changed from 300 hours to 400 hours. 0.40 parts of phthalocyanine crystal Ga-2 was obtained. The powder X-ray diffraction of the obtained Ga-2 was similar to that shown in FIG. In addition, it was confirmed by NMR measurement that 1.4 mass% of N,N-dimethylformamide was contained in the Ga-2 crystal, calculated from the proton ratio.

(Synthesis of gallium phthalocyanine crystal Ga-3)
In the above (synthesis of gallium phthalocyanine crystal Ga-1), hydroxygallium was similarly used except that 10 parts of N-methylformamide was changed to 10 parts of N,N-propylformamide and the milling treatment time was changed from 300 hours to 500 hours. 0.40 parts of phthalocyanine crystal Ga-3 was obtained. The powder X-ray diffraction of the obtained Ga-3 was similar to that shown in FIG. In addition, it was confirmed by NMR measurement that 1.4 mass% of N-propylformamide was contained in the Ga-3 crystal calculated from the proton ratio.

(Synthesis of gallium phthalocyanine crystal Ga-4)
In the above (synthesis of gallium phthalocyanine crystal Ga-1), 10 parts of N-methylformamide was replaced with 10 parts of N,N-vinylformamide, and the milling treatment time was changed from 300 hours to 100 hours. 0.40 part of phthalocyanine crystal Ga-4 was obtained. The powder X-ray diffraction of the obtained Ga-4 crystal was the same as that of FIG. It was also confirmed by NMR measurement that the Ga-4 crystal contained 1.8% by mass of N-vinylformamide, calculated from the proton ratio.

(Synthesis of gallium phthalocyanine crystal Ga-5)
0.5 part of the chlorogallium phthalocyanine (ClGa) obtained above was subjected to dry milling treatment with a ball mill for 20 hours at room temperature (23° C.) together with 20 parts of glass beads having a diameter of 0.8 mm. 10 parts of N,N-dimethylformamide was added thereto, and wet milling treatment was performed at room temperature (23° C.) for 100 hours. From this dispersion, gallium phthalocyanine crystals were taken out using N,N-dimethylformamide, filtered, and the filter was thoroughly washed with tetrahydrofuran. The filtered material was vacuum dried to obtain 0.44 part of chlorogallium phthalocyanine crystal Ga-5. The powder X-ray diffraction pattern of the obtained crystal is shown in FIG.

In addition, 1.0 mass% of N,N-dimethylformamide is contained in the Ga-5 crystal by the ¹ H-NMR method [measuring instrument: AVANCEIII 500 (manufactured by BRUKER)] using bisulfate as a solvent. It was confirmed.

(Synthesis of gallium phthalocyanine crystal Ga-6)
In the above (synthesis of gallium phthalocyanine crystal Ga-2), 0.46 parts of hydroxygallium phthalocyanine crystal Ga-6 was obtained in the same manner except that the milling treatment time was changed from 400 hours to 48 hours. In addition, it was confirmed by NMR measurement that 2.1 mass% of N,N-dimethylformamide was contained in the Ga-6 crystal, calculated from the proton ratio.

(Synthesis of gallium phthalocyanine crystal Ga-7)
In the above (synthesis of gallium phthalocyanine crystal Ga-1), hydroxygallium was similarly prepared except that 10 parts of N-methylformamide was changed to 10 parts of N,N-dimethylformamide and the milling treatment time was changed from 300 hours to 100 hours. 0.40 parts of phthalocyanine crystal Ga-7 was obtained. The powder X-ray diffraction pattern of the obtained crystal is shown in FIG. In addition, it was confirmed by NMR measurement that the Ga-7 crystal contained 2.2% by mass of N,N-dimethylformamide calculated from the proton ratio.

[Preparation of electrophotographic photoreceptor]
Hereinafter, the film thickness of each layer of the electrophotographic photosensitive member was measured by an eddy current film thickness meter Fischerscope (manufactured by Fisher Instruments) or calculated from the mass per unit area in terms of specific gravity.

<Examples 1-1 to 37, Comparative examples 1-1 to 3>
(Example 1-1)
60 parts of barium sulfate particles (trade name: Pastran PC1, manufactured by Mitsui Mining & Smelting Co., Ltd.) coated with tin oxide, 15 parts of titanium oxide particles (trade name: TITANIX JR, manufactured by Teika), resol type phenol resin (trade name: Phenolite J) -325, manufactured by Dainippon Ink and Chemicals, Inc., solid content 70% by mass 43 parts, silicone oil (trade name: SH28PA, manufactured by Toray Dow Corning) 0.015 parts, silicone resin (trade name: Tospearl 120, manufactured by Toshiba Silicone) ) A coating solution for a conductive layer was prepared by subjecting a solution consisting of 3.6 parts, 50 parts of 1-methoxy-2-propanol and 50 parts of methanol to a dispersion treatment with a ball mill for 20 hours.

  This conductive layer coating solution is applied as a support to an aluminum cylinder (JIS-A3003, aluminum alloy) having a length of 261.5 mm and a diameter of 24 mm, and the obtained coating film is dried at 140° C. for 30 minutes. Thus, a conductive layer having a film thickness of 15 μm was formed.

  Next, 10 parts of copolymerized nylon resin (trade name: Amilan CM8000, manufactured by Toray) and 30 parts of methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Teikoku Kagaku), 400 parts of methanol/n-butanol. An undercoat layer coating solution was prepared by dissolving it in 200 parts of a mixed solvent. The coating liquid for undercoat layer was applied onto the conductive layer by dip coating, and the resulting coating film was dried to form an undercoat layer (UCL-1) having a thickness of 0.7 μm.

  Next, gallium phthalocyanine crystal Ga-1 (charge generating substance) 10 parts, polyvinyl butyral (trade name: S-REC BX-1, manufactured by Sekisui Chemical Co., Ltd.) 5 parts, and cyclohexanone 250 parts, glass beads having a diameter of 1.0 mm Was subjected to a dispersion treatment for 6 hours with a sand mill using. 250 parts of ethyl acetate was added to this dispersion to dilute it to prepare a charge generation layer coating solution. This coating liquid for charge generation layer was applied onto the undercoat layer by dip coating, and the resulting coating film was dried at 100° C. for 10 minutes to form a charge generation layer having a thickness of 0.22 μm.

  Next, 110 parts of a polycarbonate resin PC, 9 parts of a mixture of the compound of the formula (102) as a charge transport substance and a compound of the following formula (mixing ratio 6:3), 70 parts of o-xylene (Xy) and dimethoxy. A coating solution for the charge transport layer was prepared by dissolving it in 20 parts of methane (DMM). This charge transport layer coating solution was applied onto the charge generation layer by dip coating, and the resulting coating film was dried at 125° C. for 1 hour to form a charge transport layer having a thickness of 15.5 μm.

(Examples 1-2 to 37, Comparative examples 1-1 to 3)
Change from the above (Example 1-1) so that the type of the charge generating substance used in the charge generating layer, the type of the resin in the charge transporting layer, the type of the solvent, and the number of parts thereof shown in Table 14 were obtained. An electrophotographic photoreceptor was produced. In Comparative Example 1-3, there were some undissolved solids in the charge transport layer coating solution, and the electrophotographic photoreceptor could not be evaluated. Further, in the table, THF means tetrahydrofuran.

[Evaluation]
The following evaluations were performed using the electrophotographic photosensitive member produced above. The evaluation results are shown in Table 14.

(Fogging suppression effect)
Laser beam printer CP-4525 (manufactured by Hewlett-Packard) was modified to adjust the charging potential (dark part potential) of the electrophotographic photosensitive member, and the charging potential (dark part potential) was set to -600V for use as an evaluation device. I was there.

  The electrophotographic photosensitive member produced above was mounted in a process cartridge (cyan color) of an evaluation device, and a test chart with a print ratio of 1% was printed on an A4 size plain paper in an environment of a temperature of 23° C. and a relative humidity of 50%. Image output was continuously performed on 30,000 sheets. The image output by the test chart was performed by repeating the continuous output of three sheets and the stop of the output for 6 seconds.

After running 30,000 sheets, the worst value F ₁ of the reflection density of the white background portion of the image and the average reflection density F ₀ of the plain paper before the image formation were measured, and F ₁ −F ₀ was taken as the fogging value. A reflection density system (reflectometer model TC-6DS, manufactured by Tokyo Denshoku Co., Ltd.) was used for measuring the density. The smaller the value, the higher the fogging suppressing effect. In the present invention, the evaluation criteria AA to E are set to the preferable levels, and F and G are set to the unacceptable levels.
AA: Fogging value was less than 1.0 A: Fogging value was 1.0 or more and less than 1.5 B: Fogging value was 1.5 or more and less than 2.0 C: Fogging value was 2 0.0 or more and less than 2.5 D: Fogging value was 2.5 or more and less than 3.0 E: Fogging value was 3.0 or more and less than 4.0 F: Fogging value was 4.0 The fogging value was 5.0 or more.

<Examples 2-1 to 287, Comparative Examples 2-1 to 8>
(Example 2-1)
60 parts of barium sulfate particles (trade name: Pastran PC1, manufactured by Mitsui Mining & Smelting Co., Ltd.) coated with tin oxide, 15 parts of titanium oxide particles (trade name: TITANIX JR, manufactured by Teika), resol type phenol resin (trade name: Phenolite J) -325, manufactured by Dainippon Ink and Chemicals, Inc., solid content 70% by mass 43 parts, silicone oil (trade name: SH28PA, manufactured by Toray Dow Corning) 0.015 parts, silicone resin (trade name: Tospearl 120, manufactured by Toshiba Silicone) ) A coating solution for a conductive layer was prepared by subjecting a solution consisting of 3.6 parts, 50 parts of 1-methoxy-2-propanol, and 50 parts of methanol to a dispersion treatment with a ball mill for 20 hours.

  This conductive layer coating solution is applied as a support to an aluminum cylinder (JIS-A3003, aluminum alloy) having a length of 261.5 mm and a diameter of 24 mm, and the obtained coating film is dried at 140° C. for 30 minutes. Thus, a conductive layer having a film thickness of 30 μm was formed.

  Next, 10 parts of copolymerized nylon resin (trade name: Amilan CM8000, manufactured by Toray) and 30 parts of methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Teikoku Kagaku), 400 parts of methanol/n-butanol. An undercoat layer coating solution was prepared by dissolving it in 200 parts of a mixed solvent. The coating liquid for undercoat layer was applied onto the conductive layer by dip coating, and the obtained coating film was dried to form an undercoat layer (UCL-1) having a thickness of 0.8 μm.

  Next, gallium phthalocyanine crystal Ga-1 (charge generating substance) 10 parts, polyvinyl butyral (trade name: S-REC BX-1, manufactured by Sekisui Chemical Co., Ltd.) 5 parts, and cyclohexanone 250 parts, glass beads having a diameter of 1.0 mm Was subjected to a dispersion treatment for 6 hours with a sand mill using. 250 parts of ethyl acetate was added to this dispersion to dilute it to prepare a charge generation layer coating solution. This coating liquid for charge generation layer was applied onto the undercoat layer by dip coating, and the obtained coating film was dried at 100° C. for 10 minutes to form a charge generation layer having a thickness of 0.23 μm.

  Next, 10 parts of Exemplified Compound 1001 (Mw: 63,000) as a polycarbonate resin, and 9 parts of a mixture of the compound of Formula (102) and the compound of Formula (205) (mixing ratio 9:1) as a charge transport material. , O-xylene (Xy) (70 parts) and dimethoxymethane (DMM) (20 parts) were dissolved to prepare a charge transport layer coating solution. This charge transport layer coating solution was applied onto the charge generation layer by dip coating, and the resulting coating film was dried at 125° C. for 1 hour to form a charge transport layer having a thickness of 20 μm.

(Examples 2-2 to 287, Comparative examples 2-1 to 8)
In Tables 15 to 20, the presence or absence of a conductive layer, the type of undercoat layer, the type of charge generating substance used in the charge generating layer, the type of resin and the weight average molecular weight Mw of the charge transporting layer, the type of charge transporting substance ( The mass ratio in the case of using two kinds together), the number of parts of the charge transport substance and the resin, the kind of the solvent and the number of parts thereof were changed from the above (Example 2-1) to prepare an electrophotographic photosensitive member. .. The exemplified compound 3001 is a polymer of group B structural unit B-101 (dielectric constant 2.11) (weight average molecular weight 63,000). Exemplified compound 3002 is a polymer of group B structural unit B-201 (dielectric constant 2.20) (weight average molecular weight 53,000). The exemplified compound 3003 is a polymer of group B structural unit B-403 (dielectric constant 2.41) (weight average molecular weight 36,000). A method for forming the undercoat layers UCL-2 and UCL-3 and a method for forming the charge generation layer using the charge generation materials CGM-1 and CGM-2 are shown below.

(Undercoat layer UCL-2)
10 parts of an electron transporting compound (ETM-1) represented by the following formula,

17 parts of a blocked isocyanate compound represented by the following formula as a crosslinking agent (trade name: Sumidule 3175, solid content: 75% by mass, made by Sumitomo Bayer Urethane),

2 parts of polyvinyl butyral resin (trade name: S-REC BX-1, manufactured by Sekisui Chemical Co., Ltd.),
0.2 parts of zinc (II) butyrate as an additive,
Was dissolved in a mixed solvent of 100 parts of tetrahydrofuran and 100 parts of 1-methoxy-2-propanol to prepare an undercoat layer coating solution. This coating liquid for undercoat layer is applied onto the conductive layer by dip coating, and the obtained coating film is heated at 160° C. for 30 minutes, dried, and cured to give an undercoat layer UCL-having a thickness of 0.7 μm. Formed 2.

(Undercoat layer UCL-3)
100 parts of zinc oxide particles (average primary particle size: 50 nm, specific surface area: 19 m ² /g, powder resistance: 4.7×10 ⁶ Ω·cm, manufactured by Teika) were mixed with 500 parts of toluene while stirring. To this, 1.25 parts of N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane (trade name: KBM602, manufactured by Shin-Etsu Chemical Co., Ltd.) was added as a surface treatment agent, and mixed with stirring for 6 hours. Then, toluene was distilled off under reduced pressure, and the surface-treated zinc oxide particles were obtained by drying at 130° C. for 6 hours. 75 parts of surface-treated zinc oxide particles, 16 parts of the blocked isocyanate compound (trade name: Sumidule 3175, solid content: 75 mass%, made by Sumitomo Bayer Urethane), polyvinyl butyral resin (trade name: S-REC BM- 9 parts of Sekisui Chemical Co., Ltd.) and 1 part of 2,3,4-trihydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to a mixed solvent of 60 parts of methyl ethyl ketone and 60 parts of cyclohexanone to prepare a dispersion liquid. This dispersion was subjected to dispersion treatment using glass beads having an average particle size of 1.0 mm in a vertical sand mill in a 23° C. atmosphere at a rotation speed of 1,500 rpm for 3 hours. After the dispersion treatment, 5 parts of crosslinked polymethylmethacrylate particles (trade name: SSX-103, average particle size: 3 μm, manufactured by Sekisui Chemical Co., Ltd.) and silicone oil (trade name: SH28PA, Toray Dow) were added to the obtained dispersion liquid. A coating solution for the undercoat layer was prepared by adding 0.01 part of Corning) and stirring. This coating liquid for undercoat layer is applied onto a support by dip coating to form a coating film, and the coating film is heated and polymerized at 160° C. for 40 minutes to form an undercoat layer UCL-3 having a thickness of 30 μm. did.

(Charge generation layer using charge generation material CGM-1)
12 parts of Y-type oxytitanium phthalocyanine crystal (charge generating substance) having a peak at 27.3° of Bragg angle (2θ±0.2°) in CuKα characteristic X-ray diffraction, polyvinyl butyral resin (trade name: S-REC BX-1 10 parts of Sekisui Chemical Co., Ltd.) and 250 parts of cyclohexanone were placed in a sand mill using glass beads having a diameter of 1.0 mm and dispersed for 3 hours to prepare a dispersion liquid. Next, 500 parts of ethyl acetate was added to this dispersion to prepare a charge generation layer coating liquid. The coating liquid for a charge generating layer is applied onto the undercoat layer by dip coating to form a coating film, and the resulting coating film is dried at a temperature of 80° C. for 10 minutes to generate a charge having a thickness of 0.20 μm. Layers were formed.

(Charge generation layer using charge generation material CGM-2)
As the charge generating substance CGM-2, 15 parts of a bisazo pigment represented by the following formula,

10 parts of polyvinyl butyral resin (trade name: S-REC BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 250 parts of tetrahydrofuran are placed in a sand mill using glass beads having a diameter of 1.0 mm and dispersed for 3 hours to prepare a dispersion liquid. did. Next, 100 parts of cyclohexanone and 500 parts of tetrahydrofuran were added to this dispersion liquid to prepare a charge generation layer coating liquid. Then, this coating solution was applied onto the undercoat layer by dip coating, and the obtained coating film was dried at 110° C. for 30 minutes to form a charge generation layer having a thickness of 0.30 μm.

[Evaluation]
The following evaluations were performed using the electrophotographic photoreceptor or the coating liquid for charge transport layer produced above. The evaluation results are shown in Tables 21 to 26.

<Evaluation of coating liquid for charge transport layer>
(Storage stability)
The coating liquid for the charge transport layer was prepared, stirred for 24 hours, and then stored for 1 month in an environment of a temperature of 23° C. and a relative humidity of 50% in a sealed state. The storage stability was evaluated by visually observing the charge transport layer coating solution after storage. The evaluation criteria are as follows.
A: There was no undissolved solid matter and the coating solution was transparent. B: There was no undissolved solid matter, but the coating solution had some turbidity. C: There was no undissolved solid matter, but there was coating. Clear turbidity was observed in the liquid D: There was a solid material that remained undissolved.
The following electrophotographic photoreceptors could not be evaluated if the storage stability of the charge transport layer coating solution was evaluated as D.

<Evaluation of electrophotographic photoreceptor>
(Fogging suppression effect)
Laser beam printer CP-4525 (manufactured by Hewlett-Packard) was modified so that the charging potential (dark area potential) of the electrophotographic photosensitive member could be adjusted, and the charging potential (dark area potential) was set to -600V for use as an evaluation device. I was there.

  The electrophotographic photosensitive member produced above was mounted in a process cartridge (cyan color) of an evaluation device, and a test chart with a print ratio of 1% was printed on an A4 size plain paper in an environment of a temperature of 23° C. and a relative humidity of 50%. Image output was continuously performed on 30,000 sheets. The image output by the test chart was performed by repeating the continuous output of three sheets and the stop of the output for 6 seconds.

After running 30,000 sheets, the worst value F ₁ of the reflection density of the white background portion of the image and the average reflection density F ₀ of the plain paper before the image formation were measured, and F ₁ −F ₀ was taken as the fogging value. A reflection density system (reflectometer model TC-6DS, manufactured by Tokyo Denshoku Co., Ltd.) was used for measuring the density. The smaller the value, the higher the fogging suppressing effect. In the present invention, the evaluation criteria AA to E are set to the preferable levels, and F and G are set to the unacceptable levels.
AA: Fogging value was less than 1.0 A: Fogging value was 1.0 or more and less than 1.5 B: Fogging value was 1.5 or more and less than 2.0 C: Fogging value was 2 0.0 or more and less than 2.5 D: Fogging value was 2.5 or more and less than 3.0 E: Fogging value was 3.0 or more and less than 4.0 F: Fogging value was 4.0 The fogging value was 5.0 or more.

(Sensitivity, electrical characteristics after repeated use)
A laser beam printer CP-4525 (manufactured by Hewlett-Packard) was modified so that the charging potential (dark area potential) and the exposure light amount of the electrophotographic photosensitive member could be adjusted and used as an evaluation device.

The electrophotographic photosensitive member produced above was mounted in a process cartridge (cyan color) of an evaluation device, and a test chart with a printing ratio of 4% was printed on an A4 size plain paper under a temperature of 23° C. and a relative humidity of 50%. Image output was continuously performed on 10,000 sheets. At this time, as a charging condition, the applied bias was adjusted so that the charging potential (dark portion potential) of the electrophotographic photosensitive member was −600V. The exposure conditions were adjusted so that the exposure light amount was 0.4 μJ/cm ² .

  The bright part potentials of the electrophotographic photosensitive member before and after the repeated use were measured by the following methods, respectively. For the light potential of the electrophotographic photosensitive member, the developing device is removed from the process cartridge of the evaluation device, a potential measuring probe (trade name: model6000B-8, made by Trek) is arranged at the developing position, and a surface potential meter (model344, made by Trek) is placed. ) Was used. The position of the potential measuring probe with respect to the electrophotographic photosensitive member was the center in the axial direction of the electrophotographic photosensitive member, and the distance between the surface of the electrophotographic photosensitive member and the measurement surface of the potential measuring probe was 3 mm.

  The sensitivity of the electrophotographic photosensitive member was evaluated from the bright part potential of the electrophotographic photosensitive member before repeated use. The higher the bright part potential of the electrophotographic photosensitive member before repeated use, the higher the sensitivity of the electrophotographic photosensitive member.

  In addition, the electrical characteristics of the electrophotographic photosensitive member during repeated use were evaluated from the variation value (difference) of the bright portion potential of the electrophotographic photosensitive member before and after repeated use. It should be noted that the smaller the fluctuation value of the light portion potential, the higher the electrical characteristics of the electrophotographic photosensitive member during repeated use.

(High-speed recording response)
Laser beam printer CP-4525 (manufactured by Hewlett-Packard) was modified to adjust the charging potential (dark area potential) of the electrophotographic photoconductor, the amount of exposure light and the developing bias. An evaluation device Y modified so that the (rotational speed of the electrophotographic photosensitive member) was 1.5 times faster was prepared.

The electrophotographic photosensitive member produced as described above is attached to the process cartridges (cyan color) of the evaluation devices X and Y, respectively, and the temperature is 23° C. and the relative humidity is 50%. The "one-dot Keima pattern halftone image" was output as the evaluation images X and Y. At this time, as a charging condition, the applied bias was adjusted so that the surface potential (dark portion potential) of the electrophotographic photosensitive member was −600V. The exposure conditions were adjusted so that the exposure light amount was 0.4 μJ/cm ² . The developing conditions were adjusted so that the developing bias was -350V.

The image density difference between the evaluation images X and Y (Macbeth density difference) was measured with a densitometer RD-918 (manufactured by Macbeth) to evaluate the high-speed recording response. Specifically, the SPI filter is used to measure the reflection density of an image of a circle having a diameter of 5 mm for any 10 points in the image area corresponding to one round of the electrophotographic photosensitive member, and the average value of the 10 points is calculated. The image density of the evaluation image was used. The smaller the image density difference, the higher the high-speed recording response. The evaluation criteria are as follows.
A: Image density difference was less than 0.02 B: Image density difference was 0.02 or more and less than 0.04 C: Image density difference was 0.04 or more and less than 0.06 D: Image The density difference was 0.06 or more.

(Long-term storage stability)
The electrophotographic photosensitive member produced as described above was mounted on a process cartridge (cyan color) of a laser beam printer CP-4525 (manufactured by Hewlett-Packard), and stored for 14 days in an environment of a temperature of 60° C. and a relative humidity of 50%. The surface of the electrophotographic photosensitive member after storage was observed with an optical microscope, and the long-term storage stability was evaluated by visually observing the image for evaluation. The image for evaluation was output by mounting the electrophotographic photosensitive member after storage on a process cartridge (cyan color) of another laser beam printer CP-4525. The evaluation criteria are as follows.
A: No precipitates were observed on the surface B: Some precipitates were observed on the surface, but it was at a level that did not affect the image quality C: Many precipitates were observed on the surface, but the image quality There was no effect on

(Photo memory suppression effect)
Laser beam printer CP-4525 (manufactured by Hewlett-Packard) was modified to adjust the charging potential (dark part potential) of the electrophotographic photosensitive member, and the charging potential (dark part potential) was set to -600V for use as an evaluation device. I was there.

The electrophotographic photosensitive member produced above was mounted in a process cartridge (cyan color) of an evaluation device, and a halftone image output was performed on an A4 size plain paper under an environment of a temperature of 23° C. and a relative humidity of 50%. It was carried out continuously for 000 sheets. After that, the electrophotographic photosensitive member was taken out of the process cartridge, a part of the surface of the electrophotographic photosensitive member was shielded from light in the circumferential direction, and a non-shielded portion was irradiated with 2,000 lux light for 10 minutes using a white fluorescent lamp. This electrophotographic photosensitive member was attached to another process cartridge (cyan color), and 30 minutes after the completion of light irradiation of the fluorescent lamp, the "one-dot Keima pattern halftone image" shown in FIG. 5 was output. .. In the halftone image, the regions corresponding to the light-shielded portion (non-irradiated portion) and the non-light-shielded portion (irradiated portion) were visually observed, and the photomemory suppression effect was evaluated from the density difference. The evaluation criteria are as follows.
A: No density difference could be confirmed B: There was a slight density difference C: There was a density difference, but it was at a level that did not pose a problem in actual use D: There was a density difference, but the boundary between regions was clear Not E: There was a clear density difference, and there were portions where the boundaries between regions were clear.

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Axis 3 Charging means 4 Exposure light 5 Developing means 6 Transfer means 7 Transfer material 8 Fixing means 9 Cleaning means 10 Pre-exposure light 11 Process cartridge 12 Guide means

Claims (7)

An electrophotographic photoreceptor having a support, a charge generation layer, and a charge transport layer containing a charge transport substance in this order,
The charge transport layer is a surface layer of the electrophotographic photoreceptor,
Charge transport layer is, possess a structural unit selected from group A, a structural unit selected from group B, a, and,
Weight average molecular weight, has contains a copolymerization port polycarbonate resin is 30,000 98,000 or less,
An electrophotographic photoreceptor, wherein the mass ratio of the charge transport material to the copolycarbonate resin is 6/10 or more and 9/10 or less .
<Group A: Structural units represented by formulas (101) and (102)>

In (formula ^{(101), R} 211 ~R ²¹⁴ are each independently a hydrogen atom, an alkyl group, an aryl group, ^{.R 215} of an alkoxy group, an alkyl group, an aryl group, and ^{.R 216} to an alkoxy group R ²¹⁷ each independently represent an alkyl group having 1 to 9 carbon atoms ^{.i 211} represents an integer of 0 to 3. ^However, the _{^{R 215 (CH 2) i CHR}} 216 R 217 are not the same.)

(In the formula (102), R ^{221 to} R ²²⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. R ²²⁵ and R ²²⁶ each independently represent an alkyl group having 1 to 9 carbon atoms. Group, provided that R ²²⁵ and R ²²⁶ are not the same. i ²²¹ represents an integer of 0 to 3.)
<Group B: Structural unit represented by formula (104 ) >

(In the formula ^(104), R 241 ^{to R 244} each independently represent a hydrogen atom, an alkyl group, an aryl group, .X showing an alkoxy group is a single bond, an oxygen atom, a sulfur atom, shown to a sulfonyl group.) Before SL copolymer Po weight average molecular weight of polycarbonate resin, electrophotographic photosensitive member according to claim 1 is 40,000 to 80,000 or less. It occupied before Symbol copolymer Po polycarbonate resin, the content ratio of structural units selected from the group A, electrophotographic photosensitive member according to claim 1 or 2 or less 20 mol% or more 70 mol%. A method for producing an electrophotographic photosensitive member according to any one of claims 1乃Itaru 3,
And the charge transport material, and before Symbol copolymer Po polycarbonate resin, dipole moment to form a coating film of the charge transport layer coating liquid containing the following solvents 1.0D, drying the coating film The method for producing an electrophotographic photosensitive member, which comprises the step of forming the charge transport layer according to 1. The method for producing an electrophotographic photosensitive member according to claim 4, wherein the solvent having a dipole moment of 1.0 D or less is selected from xylene and methylal. An electrophotographic photosensitive member according to any one of claims 1乃optimum 3, charging means, developing means, integrally supported and at least one means selected from the group consisting of the transfer means and a cleaning means, electronic A process cartridge that is detachable from the main body of the photographic device. The electrophotographic photosensitive member according to any one of claims 1乃optimum 3, and a charging means, an exposure means, the electrophotographic apparatus, characterized in that it comprises a developing means and a transfer means.