JP4069843B2 - Electrophotographic photosensitive member, process cartridge, image forming apparatus, and image forming method - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member, a process cartridge, an image forming apparatus, and an image forming method used for electrophotographic image formation, and more specifically, to electrophotographic image formation used in the field of copying machines and printers. The present invention relates to an electrophotographic photosensitive member, a process cartridge, an image forming apparatus, and an image forming method.

  Electrophotographic photoconductors have great advantages such as wider selection of materials, better environmental suitability, and lower production costs than inorganic photoconductors such as selenium photoconductors and amorphous silicon photoconductors. In recent years, organic photoreceptors have become the mainstream in place of inorganic photoreceptors.

On the other hand, in recent electrophotographic image forming methods, as a hard copy printer of a personal computer, and in an ordinary copying machine, image processing of LEDs and lasers is easy due to the ease of image processing and deployment to a multifunction machine. A digital image forming system that uses a light source has rapidly spread. Furthermore, a technique for producing a high-quality electrophotographic image by developing a finer digital image has been developed. For example, image exposure is performed with a laser beam with a small spot area, the density of the dot latent image is increased to form a high-definition latent image, the latent image is developed with a small particle size toner, and a high-quality electrophotographic image The technology for producing is disclosed. (Patent Document 1)
In forming such a high-quality digital image, an organic photoreceptor having high sensitivity and stable characteristics against changes in the greenhouse environment is required.

  Conventionally, in order to satisfy the requirements of the organic photoreceptor as described above, the organic photoreceptor has a layer structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer, and the charge transport layer has a low molecular weight of about 500. The structure contained a large amount of a molecular weight charge transporting substance. However, in the charge transport layer having such a configuration, the film quality is deteriorated, and the charge transport layer on the surface layer is easily contaminated with foreign substances. That is, the surface of the photosensitive member is easily contaminated with paper dust or a toner composition by a developing unit, a transferring unit, a cleaning unit, and the like arranged around the photosensitive member. As a result, a black spot (a wrinkled spot image) or a transfer Periodic image defects such as missing are likely to occur. In addition, in a high-speed copying machine or a low-temperature and low-humidity environment where the time between the exposure process and the development process is short, sufficient sensitivity cannot be obtained. It is easy to occur.

  As a method for solving such a problem, it has been reported to use a charge transport material having a large molecular weight. For example, an organic photoreceptor containing a charge transport material having a chemical structure of bisstyryl and a molecular weight of 1000 or more has been reported (Patent Document 2). However, when these charge transport materials are contained in the charge transport layer, the charge transport layer tends to have insufficient compatibility with the binder resin, the charge transport material is not uniformly dispersed, and the sensitivity is not sufficient. Breaking scratches such as cracks are likely to occur in the transport layer. In addition, a photoconductor using a charge transport material having a molecular weight of 3000 to 5000 is also reported (Patent Documents 3 and 4), but since the terminal group is not blocked, the residual power is likely to increase. Further, compatibility with the binder resin has not been sufficiently solved.

In order to prevent contamination on the surface of the photoreceptor, an organic photoreceptor having a surface layer containing fluorine-based resin particles has been proposed (Patent Document 5). However, an organic photoreceptor containing fluorine resin particles tends to cause image blur. Also, the mechanical strength of the surface layer is likely to be lowered, and the surface of the photoreceptor is easily worn by contact friction with the cleaning means or the like, and a good electrophotographic image cannot always be provided.
Japanese Patent Laid-Open No. 2001-255585 JP-A-3-149560 Japanese Patent Laid-Open No. 10-310635 JP-A-5-25102 JP-A-63-65449

  The present invention has been proposed in order to solve the above-described problems. The object of the present invention is to provide a high-sensitivity, easy-to-occurrence in high-speed copying and low-temperature and low-humidity environments when forming an electrophotographic image. This is to prevent image defects caused by the reduction, that is, reversal development, image density reduction due to potential fluctuation of solid black image portion and sharpness reduction due to occurrence of character thinning, etc. Prevents periodic image defects such as black spots and transfer defects that are likely to occur due to surface contamination, and does not cause cracks and other flaws, resulting in high-density, high-resolution clear electrophotographic images Is to provide an electrophotographic photosensitive member stably obtained, and a process cartridge, an image forming method, and an image forming apparatus using the electrophotographic photosensitive member.

  As a result of intensive studies, the present inventors have conducted detailed studies on the binder resin and the charge transport material constituting the charge transport layer of the electrophotographic photosensitive member in order to solve the problems of the present invention. By using a mixture of compounds having the following chemical structural units and different molecular weights as a charge transport material, even if a large molecular weight charge transport material is used, the compatibility with the binder resin is good and the process is fast. By combining with a surface layer containing inorganic particles, the high-speed response of sensitivity in a low-temperature, low-humidity environment is improved, and the surface of the photoconductor is not easily contaminated while maintaining high-speed response of sensitivity. It is observed that periodic image defects such as missing are prevented, and clear images with high density and high resolution can be stably obtained without causing breakage such as cracks. And, to complete the present invention.

The object of the present invention is achieved by adopting one of the following configurations.
(Claim 1)
When the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the following general formula (1) and having a distribution based on n is x, and the composition ratio of the compound of the 2-position component is y, x + y is 99. % Of a mixed compound, and the surface layer contains inorganic particles.

General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group is a charge transporting group, and X and Y represent a hydrogen atom, a halogen atom, or a monovalent organic group. N represents an integer of 0 to 10 (provided that both X and Y are hydrogen atoms or halogen atoms, n is an integer of 1 to 10).
(Claim 2)
In the electrophotographic photosensitive member in which a charge generation layer having a charge generation material and a charge transport layer having a charge transport layer are laminated on a conductive support, the charge transport layer has a chemical structure of the general formula (1). In addition, the composition ratio of the compound of the maximum component of the mixed compound having a distribution based on n is x, and the composition ratio of the compound of the 2-position component is y. An electrophotographic photosensitive member having a surface layer containing
(Claim 3)
3. The electrophotographic photosensitive member according to claim 1, wherein x + y in the general formula (1) is in the following range.

    30% ≦ x + y ≦ 99%

(Claim 4 )
The electrophotographic photoreceptor according to any one of claims 1 to 3 , wherein the CTM group of formula (1), X, and Y have a chemical structure represented by the following formula A.

In formula A, Ar ₁ represents a monovalent substituted or unsubstituted aromatic group, Ar ₂ represents a divalent substituted or unsubstituted aromatic group, R ₁ to R ₃ is a hydrogen atom, 1 A valent substituted or unsubstituted aromatic group is shown, and A represents a divalent group containing a triarylamine group . A plurality of Ar ₁ , R ₁ , R ₂ , and R ₃ may be different from each other. p and q each represents an integer of 0 or 1.

(Claim 5 )
The electrophotographic photosensitive member according to any one of claims 1 to 3 , wherein the CTM group of formula (1), X and Y have a chemical structure represented by formula B below.

一般式（２）中、Ｙは単結合である。
（請求項６）
前記Ａのトリアリールアミン基を含有する２価の基が、下記一般式（４）の基であることを特徴とする請求項４又は５に記載の電子写真感光体。 In the general formula B, Ar ₁ is a divalent substituted or unsubstituted aromatic group, a divalent furan group, or represents a lower following general formula (2), R ₁ ~R ₃ is a hydrogen atom , A represents a divalent group containing a triarylamine group, and B represents a monovalent substituted or unsubstituted aromatic group. However, a plurality of B, R ₁ , R ₂ and R ₃ may be different from each other. m represents an integer of 0 or 1, respectively.

In general formula (2), Y is a single bond.
(Claim 6 )
6. The electrophotographic photosensitive member according to claim 4, wherein the divalent group containing the triarylamine group of A is a group of the following general formula (4).

In the general formula (4), Ar ₃ represents a substituted or unsubstituted monovalent aromatic group.
(Claim 7 )
The electrophotographic photosensitive member according to claim 6 , wherein Ar ₃ is a group of the following general formula (5).

In General Formula (5), R ₃₁ , R ₃₂ , R ₃₃ , R ₃₄ , and R ₃₅ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. However, at least one of R ₃₁ and R ₃₅ is an alkyl group having 1 to 4 carbon atoms.
(Claim 11)
The electrophotographic photoreceptor according to claim 7 or 8, wherein the divalent group containing the triarylamine group of A is a group of the following general formula (6).

In General Formula (6), X ₂ represents a single bond , and Ar ₄ and Ar ₅ represent a substituted or unsubstituted monovalent aromatic group.
(Claim 9 )
6. The electrophotographic photosensitive member according to claim 5 , wherein B is a group represented by the following general formula (7).

In the general formula (7), R ₄₁ , R ₄₂ , R ₄₃ , R ₄₄ , R ₄₅ , R ₅₁ , R ₅₂ , R ₅₃ , R ₅₄ , and R ₅₅ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. . However, at least one of R ₄₁ , R ₄₅ , R ₅₁ and R ₅₅ is an alkyl group having 1 to 4 carbon atoms.
(0 claim 1)
The electrophotographic photosensitive member according to any one of claims 1 to 3 , wherein the CTM group, X and Y in the general formula (1) has a chemical structure represented by the following general formula C.

In the general formula C, Ar ₁ is a monovalent substituted or unsubstituted aromatic group, Ar ₂ is a divalent substituted, unsubstituted aromatic group, divalent heterocyclic group, or the following general formula (8) R represents a monovalent substituted or unsubstituted aromatic group. However, the plurality of Ar ₁ , Ar ₂ , and R may be different from each other.

In the general formula (8), Y is oxygen atom. However R _1, R ₂ is hydrogen atom.
(Claim 1 1 )
The electrophotographic photosensitive member according to any one of claims 1 to 1 0 the number average primary particle diameter dn of the inorganic particles is characterized by a 5 nm to 200 nm.
(Claim 1 2 )
The electrophotographic photosensitive member according to any one of claims 1 to 11, wherein the inorganic particles satisfy the following formula (a).

Formula (a) 0.5 <number average primary particle size dn / 90% span value Δd <0.7
(Claim 1 3 )
The electrophotographic photosensitive member according to any one of claims 1 to 1 2, wherein the inorganic particles are strained facilities to hydrophobic surface treatment.
(Claims 1-4)
The electrophotographic photoreceptor according to any one of claims 1 to 12 , wherein the inorganic particles are hydrophobic silica.
(Claim 1 5 )
Assuming that the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the general formula (1) and having a distribution based on n is x, the composition ratio of the compound of the 2-position component is y, x + y is 99. % Of a mixed compound and a surface layer containing inorganic particles, a charging means for uniformly charging the electrophotographic photosensitive member, and an electrostatic latent image on the charged electrophotographic photosensitive member A latent image forming means for forming a toner image, a developing means for visualizing an electrostatic latent image on the electrophotographic photosensitive member, and a transfer means for transferring a toner image visualized on the electrophotographic photosensitive member onto a transfer material And at least one of a charge removing means for removing the charge on the electrophotographic photosensitive member after transfer and a cleaning means for removing the residual toner on the electrophotographic photosensitive member after transfer. It is characterized by being detachably attachable to the forming device body Process cartridge that.
(Claim 1 6 )
Charging means for uniformly charging the electrophotographic photosensitive member, latent image forming means for forming an electrostatic latent image on the charged electrophotographic photosensitive member, and developing the electrostatic latent image on the electrophotographic photosensitive member In an image forming apparatus having a developing unit and a transfer unit that transfers a toner image visualized on the electrophotographic photosensitive member onto a transfer material, the electrophotographic photosensitive member has a chemical structure represented by the general formula (1). X + y is 99% or less, and the composition ratio of the compound of the maximum component of the mixed compound having a distribution based on n is x, and the composition ratio of the compound of the 2-position component is y, and the surface An image forming apparatus, wherein the layer contains inorganic particles.
(Claim 17 )
An image forming method comprising forming an electrophotographic image using the image forming apparatus according to claim 16 .

  By using the electrophotographic photosensitive member, the process cartridge, the image forming method, and the image forming apparatus of the present invention, the high-speed responsiveness of the sensitivity that is likely to occur in a high-speed and low-temperature and low-humidity environment is insufficient, and the image defect and high-temperature high Various image defects that are likely to occur due to moisture can be prevented, and an electrophotographic image having good image density and sharpness can be provided.

  Hereinafter, the present invention will be described in detail.

  The electrophotographic photosensitive member of the present invention has the chemical structure of the following general formula (1), and the composition ratio of the compound of the maximum component of the mixed compound having a distribution based on n is x. If y is y, x + y contains 99% or less of a mixed compound, and the surface layer contains inorganic particles.

General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group is a charge transporting group, and X and Y represent a hydrogen atom, a halogen atom, or a monovalent organic group. N represents an integer of 0 to 10 (provided that both X and Y are hydrogen atoms or halogen atoms, n is an integer of 1 to 10).

  The electrophotographic photosensitive member used in the present invention is an electrophotographic photosensitive member in which a charge generating layer having a charge generating substance and a charge transporting layer having a charge transporting layer are laminated on a conductive support. , Where x is the composition ratio of the compound of the largest component of the mixed compound having the chemical structure of the general formula (1) and has a distribution based on n, and y is the composition ratio of the compound of the 2-position component. It has a surface layer containing 99% or less of a mixed compound and containing inorganic particles.

  The electrophotographic photosensitive member of the present invention has the above-described configuration, and can prevent sharpness reduction such as thinning of characters due to sensitivity reduction, which is likely to occur in high-speed copying and low-temperature and low-humidity environments. In addition, no periodic image defects such as transfer defects are generated, and no flaws such as cracks are generated, so that a clear electrophotographic image having a high density and a high resolving power can be produced.

  In the present invention, when the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the general formula (1) and having a distribution based on n is x, the composition ratio of the compound of the 2-position component is y. , X + y containing 99% or less of a mixed compound is a mixture of compounds of general formula (1) and having different numbers of chain structures of CTM groups, that is, charge transporting groups (= n as a reference) Compound having a distribution), among the mixed compounds (mixed compounds), x is the composition ratio (existence ratio) of the compound having the largest abundance ratio, and x is the composition ratio (abundance ratio) of the compound at the 2-position component. ) Is y, it means that x + y is 99% or less, and the mixed compound contains at least three compounds of the general formula (1) having different n. By using such a mixed compound as a charge transporting material, the charge transporting property is remarkably improved, the high speed compatibility, the sensitivity failure under low temperature and low humidity, etc. can be overcome, and the compatibility with the solvent and the binder resin is remarkably improved. By combining with a surface layer that is improved and contains inorganic particles, the occurrence of periodic image defects such as black spots and transfer defects are prevented while maintaining high-speed response of sensitivity, and breakage such as cracks An electrophotographic photoreceptor capable of producing a clear image with high density and high resolution without causing scratches or the like can be obtained.

  The CTM group of the general formula (1), that is, the charge transporting group is a group whose chemical structural group has a property of having drift mobility of electrons or holes. Another definition is Time-Of- It can be defined as a group capable of obtaining a detection current resulting from charge transport by a known method capable of detecting charge transport performance such as the Flight method.

  When the CTM group cannot exist by itself, the compound of the general formula (H (CTM group) H) in which hydrogen atoms are added to both ends of the CTM group may be a charge transporting compound.

  Assuming that the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the general formula (1) and having a distribution based on n is x, the composition ratio of the compound of the 2-position component is y, x + y is 99. As specific examples of the mixed compound of not more than%, various chemical structures can be considered. In the present invention, these mixed compounds can be produced by a series of synthesis methods and can achieve the object of the present invention (charge transport materials). ), Mixed compounds of general formula A, general formula B, and general formula C described below are exemplified.

  The mixed compound of general formula A has the following chemical structure.

In formula A, Ar ₁ represents a monovalent substituted or unsubstituted aromatic group, Ar ₂ represents a divalent substituted or unsubstituted aromatic group, R ₁ to R ₃ is a hydrogen atom, 1 A valent substituted or unsubstituted aromatic group is shown, and A represents a divalent group containing a triarylamine group . A plurality of Ar ₁ , R ₁ , R ₂ , and R ₃ may be different from each other. p and q each represents an integer of 0 or 1.

  The mixed compound of the general formula B has the following chemical structure.

In the general formula B, Ar ₁ is a divalent substituted or unsubstituted aromatic group, a divalent furan group, or represents the general formula (2), R ₁ ~R ₃ is a hydrogen atom, A represents a divalent group containing a triarylamine group, and B represents a monovalent substituted or unsubstituted aromatic group. However, a plurality of B, R ₁ , R ₂ and R ₃ may be different from each other. m represents an integer of 0 or 1, respectively.

  In General Formula A and General Formula B, the divalent group containing a triarylamine group has a structure in which a trivalent linking group of a nitrogen atom is bonded to an aromatic ring, and the entire group A group having a divalent linking group is meant.

As the monovalent substituted or unsubstituted aromatic group of Ar _{1 in} the general formulas A and B, a substituted or unsubstituted phenyl group, a naphthyl group, and the like are preferable, and the substituent has 1 to 4 carbon atoms. Of these, an alkyl group, an alkoxy group, a phenyl group, a halogen atom and the like are preferable.
As the divalent substituted or unsubstituted aromatic group of Ar ₂ , a phenylene group, a naphthylene group, a biphenylene group or the like is preferable, and as the substituent, an alkyl group is preferable. A divalent furan group and a divalent thiophene group are also preferred.

R _{1 to} R ₃ represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a monovalent substituted or an unsubstituted aromatic group, a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, An alkoxy group, an unsubstituted phenyl group, a halogen, or a phenyl group having an alkyl group having 1 to 4 carbon atoms is preferred.

  As the divalent group of A, in addition to the group of the general formula (3), the group of the general formula (4) or the general formula (6) is preferable as the divalent group containing a triarylamine group.

R ₆ in the general formula (3) represents a substituted, unsubstituted alkyl group, substituted, or unsubstituted aromatic group, preferably an alkyl group having 1 to 4 carbon atoms, a phenyl group, or the like.

Ar ₃ in the general formula (4) is a substituted or unsubstituted monovalent aromatic group, preferably a phenyl group substituted with an unsubstituted phenyl group, an alkyl group having 1 to 4 carbon atoms or an alkoxy group. Is mentioned.

Ar ₄ and Ar ₅ in the general formula (6) represent a substituted or unsubstituted monovalent aromatic group, preferably substituted with an unsubstituted phenyl group, an alkyl group having 1 to 4 carbon atoms or an alkoxy group. And phenyl group.

  Hereinafter, typical chemical structures of the general formula A and the general formula B are listed below, but the present invention uses a mixture (mixed compound) of compounds having different n in the following chemical structures as a charge transport material. That is. Moreover, even if the following chemical structure is the same, if p or q of General Formula A or m of General Formula B is different, it is another mixed compound. For example, the following chemical structure No. 1A is another mixed compound in which p or q is 0 and 1. Further, even if p or q is the same, another mixed compound is obtained if the distribution is different.

  Specific examples of general formula A

The above compound examples are examples of chemical structures in which a plurality of Ar ₁ , R ₁ , R ₂ and R ₃ in the general formula A are the same, but in the present invention, the plurality of Ar ₁ , R ₁ and R _{2 are the same.} , R ₃ are not the same. For example, the following chemical structure examples of the general formula A ′ are also exemplified as the chemical structure examples of the general formula (1) of the present invention.

In general formula A ′, Ar ₁ and Ar ₁ ′ represent a monovalent substituted or unsubstituted aromatic group, and Ar ₂ represents a divalent substituted, unsubstituted aromatic group, furan group or thiophene group, Wherein R _{1 to} R ₃ , R ₁ ′ to R ₃ ′ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a monovalent substituted or unsubstituted aromatic group, and A represents triaryl A divalent group containing an amine group or the group of the general formula (3) is shown. However, Ar ₁ and R ₁ , Ar ₁ ′ and R ₁ ′ may be bonded to each other to form a ring. p and q each represents an integer of 0 or 1.

  The chemical structures of typical compounds of the general formula A ′ are listed below. In the present invention, a mixed compound having a distribution based on n in each chemical structure, x = y is 99% or less, where x is the composition ratio of the compound of the largest component, and y is the composition ratio of the compound of the 2-position component. Is used as a charge transport material.

  Below, the synthesis example of the said mixed compound (general formula A) of this invention is described.

  In the following synthesis examples, raw materials and the like will be described using the numbers given in the compound synthesis mechanism (scheme).

  Synthesis Example (1); Synthesis of Compound (Exemplary Chemical Structure 21A (p = q = 0))

A 100 ml four-head flask was equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer. Was stirred while being introduced.
1 compound: 2.06 g (0.006 mol), 2 compound: 1.13 g (0.003 mol) and 3 compound: 1.92 g (0.0063 mol) dissolved in 20 ml of THF, 4 (potassium-tert- The solution was slowly added dropwise to a mixed solution of butoxide / THF while maintaining the internal temperature at 45 ° C. or lower. After completion of dropping, the reaction was carried out for 5 hours while maintaining the internal temperature of 45 to 50 ° C.

  A separate 200 ml beaker was equipped with a stirrer, and 20 ml of methanol was added and stirred. The reaction solution reacted for 5 hours was poured into this, and then 20 ml of water was further poured into it, followed by stirring for about 30 minutes and filtration. Methanol / water = 1/1 Washed with about 40 ml and dried at 50-60 ° C. overnight to obtain crude crystals.

  The crude crystals were dissolved in 30 ml of toluene, 3 g of Wakogel B-0 (Wako Pure Chemical Industries) was added, and the mixture was stirred for about 30 minutes and filtered. Wakogel B-0 was washed with 30 ml of toluene, and the filtrate and washings were concentrated to dryness. 10 ml of ethyl acetate was added and dissolved, dropped into 60 ml of methanol and purified by reprecipitation, filtered and dried to obtain 2.54 g of the compound having the exemplified chemical structure 21A (p = q = 0). As a result of high performance liquid chromatography and mass spectrometry, the obtained compound is a mixture of n of 0 to 4, and the composition ratio (area ratio of high performance liquid chromatography) is n = 0/1/2/3/4 = It was 25.4 / 48.8 / 18.1 / 6.3 / 1.4.

  The measurement conditions for high performance liquid chromatography were as follows.

Measuring instrument: Shimadzu LC6A (manufactured by Shimadzu Corporation)
Column: CLC-ODS (manufactured by Shimadzu Corporation)
Detection wavelength: 290 nm
Mobile phase: mixed solvent of methanol / tetrahydrofuran = 3/1 Mobile phase flow rate: about 1 ml / min
The composition ratio of the mixed compound of the present invention is defined by the area ratio of each component after composition separation by liquid chromatography (area ratio in% display, total composition ratio 100%). Among the measurement conditions, the measuring device, column, mobile phase, and the like may be changed to others as long as the separation of the mixed compound can be clearly performed and the same result as in the present invention can be obtained.

  Synthesis Example (2); Synthesis of Compound (Exemplary Chemical Structure 21A (p = 1, q = 0))

A 100 ml four-headed flask is equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and 4 (potassium-tert-butoxide): 1.68 g (0.015 mol) and 20 ml of THF are added and stirred while introducing nitrogen did.
1 compound: 2.06 g (0.006 mol), 2 compound: 1.13 g (0.003 mol) and 3 compound: 2.08 g (0.0063 mol) were dissolved in 20 ml of THF to dissolve 4 (potassium-tert- The solution was slowly added dropwise to a mixed solution of butoxide / THF while maintaining the internal temperature at 45 ° C. or lower. After completion of dropping, the reaction was carried out for 5 hours while maintaining the internal temperature of 45 to 50 ° C.

  Separately, a 200 ml beaker was equipped with a stirrer, and 20 ml of methanol was added and stirred. The reaction solution reacted for 5 hours was poured into this, and then 20 ml of water was further poured into it, followed by stirring for about 30 minutes and filtration. Methanol / water = 1/1 Washed with about 40 ml and dried at 50-60 ° C. overnight to obtain crude crystals.

  The crude crystals were dissolved in 30 ml of toluene, 3 g of Wakogel B-0 (Wako Pure Chemical Industries) was added, and the mixture was stirred for about 30 minutes and filtered. Wakogel B-0 was washed with 30 ml of toluene, and the filtrate and washings were concentrated to dryness. This was dissolved in 10 ml of ethyl acetate, added dropwise to 60 ml of methanol, purified by reprecipitation, filtered and dried to obtain 2.75 g of the compound having the exemplified chemical structure 21A (p = 1, q = 0). As a result of the same high performance liquid chromatography and mass spectrometry as described above, the obtained compound is a mixture of n = 0-4, and the composition ratio (area ratio of high performance liquid chromatography) is n = 0/1/2 / 3/4 = 33.4 / 46.8 / 15.0 / 4.0 / 0.8.

  Synthesis Example (3); Synthesis of Compound (Exemplary Chemical Structure 14A (p = 1, q = 0))

A 100 ml four-headed flask is equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and 4 (potassium-tert-butoxide): 1.68 g (0.015 mol) and 20 ml of THF are added and stirred while introducing nitrogen did.
1 compound: 1.89 g (0.006 mol), 2 compound: 1.13 g (0.003 mol) and 3 compound: 1.60 g (0.0063 mol) were dissolved in 20 ml of THF to dissolve 4 (potassium-tert- The solution was slowly added dropwise to a mixed solution of butoxide / THF while maintaining the internal temperature at 45 ° C. or lower. After completion of dropping, the reaction was carried out for 5 hours while maintaining the internal temperature of 45 to 50 ° C.

  Separately, a 200 ml beaker was equipped with a stirrer, and 20 ml of methanol was added and stirred. The reaction solution reacted for 5 hours was poured into this, and then 20 ml of water was further poured into it, followed by stirring for about 30 minutes and filtration. Methanol / water = 1/1 Washed with about 40 ml and dried at 50-60 ° C. overnight to obtain crude crystals.

  The crude crystals were dissolved in 30 ml of toluene, 3 g of Wakogel B-0 (Wako Pure Chemical Industries) was added, and the mixture was stirred for about 30 minutes and filtered. Wakogel B-0 was washed with 30 ml of toluene, and the filtrate and washings were concentrated to dryness. 10 ml of ethyl acetate was added and dissolved, dropped into 60 ml of methanol and purified by reprecipitation, filtered and dried to obtain 2.32 g of a compound having the exemplified chemical structure 14A (p = 1, q = 0). As a result of the same high performance liquid chromatography and mass spectrometry as described above, the obtained compound is a mixture of n = 0-4, and the composition ratio (area ratio of high performance liquid chromatography) is n = 0/1/2 / 3/4 = 30.1 / 45.4 / 16.7 / 6.0 / 1.8.

  Specific examples of general formula B

More compounds embodiment, a plurality of B in the general formula B, R _1, R _2, but R ₃ are the same of compound examples, in the present invention, the plurality of B, R _1, R _2, R ₃ Are also included. For example, the following compound of the general formula B ′ is also exemplified as the compound of the general formula B of the present invention.

In general formula B ′, Ar ₁ represents a divalent substituted or unsubstituted aromatic group, furan group or thiophene group, and R _{1 to} R ₃ and R ₁ ′ to R ₃ ′ represent a hydrogen atom, substituted and unsubstituted. An alkyl group, a monovalent substituted or unsubstituted aromatic group, A represents a divalent group containing a triarylamine group or a group of the general formula (3), and B and B ′ represent a monovalent group. A substituted or unsubstituted aromatic group. m represents an integer of 0 or 1, respectively.

  The chemical structures of representative compounds of the general formula B ′ are listed below. In the present invention, a mixed compound having a distribution based on n in each chemical structure, x = y is 99% or less, where x is the composition ratio of the compound of the largest component, and y is the composition ratio of the compound of the 2-position component. Is used as a charge transport material.

  Below, the synthesis example of the said mixed compound (general formula B) of this invention is described.

  Synthesis Example (4); Synthesis of Compound (Exemplary Chemical Structure 12B (m = 0))

  A 100 ml four-headed flask was equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer. Was stirred while being introduced.

  1 compound: 1.0 g (0.003 mol), 2 compound: 2.65 g (0.007 mol) and 3 compound: 2.52 g (0.008 mol) were dissolved in 20 ml of THF, and the above 4 (potassium-tert. -Butoxy) / THF was slowly added dropwise while maintaining the internal temperature at 45 ° C. or lower. After completion of dropping, the reaction was carried out for 5 hours while maintaining the internal temperature of 45 to 50 ° C.

  Separately, a 200 ml beaker was equipped with a stirrer, and 20 ml of methanol was added and stirred. The reaction solution reacted for 5 hours was poured into this, and then 20 ml of water was further poured into it, followed by stirring for about 30 minutes and filtration. Methanol / water = 1/1 Washed with about 40 ml and dried at 50-60 ° C. overnight to obtain crude crystals.

  This crude crystal was dissolved in 30 ml of toluene, 3 g of Wakogel B-0 (Wako Pure Chemical Industries) was added, and the mixture was stirred for about 30 minutes and filtered. Wakogel B-0 was washed with 30 ml of toluene, and the filtrate and washings were concentrated to dryness. 10 ml of ethyl acetate was added and dissolved therein, and the resulting solution was added dropwise to 60 ml of methanol for reprecipitation purification, followed by filtration and drying to obtain 3.20 g of a compound having an exemplary chemical structure 12B (m = 0).

  As a result of the same high performance liquid chromatography and mass spectrometry as in Synthesis Example 1A, the obtained compound was a mixture of n = 0 to 5, and the composition ratio (area ratio of high performance liquid chromatography) was n = 0/1/2. /3/4=24.3/44.4/21.5/7.2/2.3/0.3.

  The measurement conditions for high performance liquid chromatography were as follows.

  Synthesis Example (5); Synthesis of Compound (Exemplary Chemical Structure 11B (m = 0))

  A 100 ml four-headed flask is equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and 4 (potassium-tert-butoxide): 1.96 g (0.075 mol) and 20 ml of THF are added and stirred while introducing nitrogen. did.

  1 compound: 1.0 g (0.003 mol), 2 compound: 2.46 g (0.007 mol) and 3 compound: 2.41 g (0.008 mol) were dissolved in 20 ml of THF to dissolve 4 (potassium-tert- The solution was slowly added dropwise to a mixed solution of butoxide / THF while maintaining the internal temperature at 45 ° C. or lower. After completion of dropping, the reaction was carried out for 5 hours while maintaining the internal temperature of 45 to 50 ° C.

  Separately, a 200 ml beaker was equipped with a stirrer, and 20 ml of methanol was added and stirred. After pouring a reaction liquid into this, 20 ml of water was further poured, and it stirred for about 30 minutes and filtered. Methanol / water = 1/1 Washed with about 40 ml and dried overnight at 50-60 ° C. to obtain crude crystals.

  The crude crystals were dissolved in 30 ml of toluene, 3 g of Wakogel B-0 (Wako Pure Chemical Industries) was added, and the mixture was stirred for about 30 minutes and filtered. Wakogel B-0 was washed with 30 ml of toluene, and the filtrate and washings were concentrated to dryness. This was dissolved in 10 ml of ethyl acetate, dropped into 60 ml of methanol, purified by reprecipitation, filtered and dried to obtain 3.35 g of a compound having the exemplified chemical structure 11B (m = 0).

  As a result of the same high performance liquid chromatography and mass spectrometry as described above, the obtained compound was a mixture of n = 0 to 4, and the composition ratio (area ratio of high performance liquid chromatography) was n = 0/1/2/3. /4=32.5/45.0/16.5/6.2/1.6.

  The mixed compound of general formula C has the following chemical structure.

In the general formula C, Ar ₁ is a monovalent substituted or unsubstituted aromatic group, Ar ₂ is a divalent substituted, unsubstituted aromatic group, divalent heterocyclic group, or the general formula (8) R represents a monovalent substituted or unsubstituted aromatic group. However, the plurality of Ar ₁ , Ar ₂ , and R may be different from each other.

In the general formula (8), Y is oxygen atom. However R _1, R ₂ is hydrogen atom.

In general formula C, Ar ₁ is a monovalent substituted or unsubstituted aromatic group, preferably a phenyl group substituted with an unsubstituted phenyl group, an alkyl group having 1 to 4 carbon atoms or an alkoxy group. It is done.

Further, the divalent substituted or unsubstituted aromatic group of Ar ₂ is preferably a phenylene group, a naphthylene group, a biphenylene group or the like, and the substituent is preferably an alkyl group. As the divalent heterocyclic group for Ar _2, a divalent furan group, a divalent thiophene group, and the like are preferable.

  Specific examples of general formula C

  Below, the synthesis example of the said mixed compound (general formula C) of this invention is described.

Synthesis Example (6): Synthesis of Compound (Exemplary Chemical Structure 17C) A 100 ml four-headed flask was equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and 2,4-dimethylaniline: 4.08 g (0. 04 mol), iodobenzene: 4.08 g (0.02 mol), m-diiodobenzene: 9.9 g (0.03 mol), copper powder 1.27 g (0.02 mol), potassium carbonate 11.04 g (0.08 mol) ) And allowed to react at 190 ° C. for 30 hours while introducing nitrogen.
The reaction solution was cooled to about 60 ° C., 200 ml of THF was added, and the mixture was stirred and filtered. The filtrate was concentrated and dissolved in 100 ml of toluene, 10 g of Wakogel B-0 (Wako Pure Chemical Industries) was added, and the mixture was stirred for about 30 minutes and filtered. Wakogel B-0 was washed with 30 ml of toluene, and the filtrate and washings were concentrated to dryness. This was dissolved by adding 20 ml of THF, dropped into 120 ml of methanol, purified by reprecipitation, filtered and dried to obtain 5.15 g of a compound having an exemplary chemical structure 17C.

  As a result of high performance liquid chromatography and mass spectrometry, the obtained compound was n = 0/1/2/3/4/5/6/7 = 2.7 / 9.0 / 24.3 / 34.2 / 20. 1 / 7.8 / 1.7 / 0.2. Moreover, the weight average molecular weight (polystyrene conversion) Mw calculated | required from the gel permeation chromatography (GPC) was 910.

Synthesis Example (7); Synthesis of Compound (Exemplary Chemical Structure 53 C) A 100 ml four-head flask was equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and 3,4-dimethylaniline: 6.05 g (0 0.05 mol), iodobiphenyl: 5.60 g (0.02 mol), bis (4-bromophenyl) ether: 13.11 g (0.04 mol), copper powder 1.59 g (0.025 mol), potassium carbonate 13.8 g (0.1 mol) was added and reacted at 190 ° C. for 30 hours while introducing nitrogen. The reaction solution was cooled to about 60 ° C., 200 ml of THF was added, and the mixture was stirred and filtered. The filtrate was concentrated and dissolved in 100 ml of toluene, 10 g of Wakogel B-0 (Wako Pure Chemical Industries) was added, and the mixture was stirred for about 30 minutes and filtered. Wakogel B-0 was washed with 30 ml of toluene, and the filtrate and washings were concentrated to dryness. This was dissolved in 20 ml of THF, added dropwise to 120 ml of methanol, purified by reprecipitation, filtered and dried to obtain 10.56 g of a compound having an exemplary chemical structure 53 C.

  As a result of high performance liquid chromatography and mass spectrometry, the obtained compound was n = 0/1/2/3/4/5/6/7/8 = 0.9 / 3.4 / 12.0 / 22.8. /31.3/19.9/6.9/2.5/0.3. Moreover, the weight average molecular weight (polystyrene conversion) Mw calculated | required from the gel permeation chromatography (GPC) was 1684.

  In the structure of the general formula (1) of the present invention, it has a compound having a distribution based on n, the composition ratio of the compound of the maximum component of the compound is x, and the composition ratio of the compound of the 2-position component is y Then, although x + y contains a mixed compound of 99% or less, the x + y is preferably 30% to 99%, and more preferably 45% to 90%. When x + y is less than 30%, the distribution of n is too wide, the molecular weight tends to increase, and the solubility and compatibility with the solvent and binder resin tend to deteriorate. On the other hand, when the ratio is larger than 99%, the solubility and compatibility with the solvent and the binder resin are likely to be similarly deteriorated when the low molecular weight ratio is decreased.

  Moreover, in the said general formula, although n is 0-10, n may contain the component 11 or more. That is, the maximum component and the second-position component exist between n = 0 and 10, and x + y may be 99% or less.

  The average molecular weight of the mixed compound of the present invention is preferably 650 to 2500, and more preferably 800 to 2300. The average molecular weight is expressed in terms of polystyrene equivalent weight average molecular weight. When the average molecular weight exceeds 2500, the solvent solubility decreases, and the compatibility of the charge transport layer with the binder resin deteriorates. As a result, the dispersibility of the charge transport material is reduced. The electrophotographic characteristics such as sensitivity and uniform chargeability are significantly reduced. On the other hand, even if it is less than 650, when combined with a surface layer containing inorganic particles, sensitivity is likely to decrease, and particularly high-speed response tends to decrease.

  The electrophotographic photoreceptor of the present invention is characterized in that the surface layer contains inorganic particles. The surface layer may be a charge transport layer as long as one of the layers forms the free surface of the photoreceptor, but the charge generation layer of the photosensitive layer or a protective layer containing inorganic particles on the surface of the charge transport layer. More preferably, it is provided as a layer.

  Further, the organic photoreceptor of the present invention has at least a charge generation layer having a charge generation material, a charge transport layer having a charge transport layer and a protective layer on a conductive support, and the protective layer contains inorganic particles. It is preferable.

  The composition ratio of the maximum component compound of the mixed compound having such a protective layer, having the chemical structure of the general formula (1), and having a distribution based on n is x. When the composition ratio is y, an electrophotographic photosensitive member containing a mixed compound with x + y of 99% or less as a charge transport material is likely to occur in high-speed copying and low-temperature and low-humidity environments. Sharpness degradation can be prevented, periodic image defects such as black spots and transfer defects are not generated, and cracks and other fractures are not generated, and high-density, high-resolution clear electrophotographic images Can be produced.

  The inorganic particles used in the present invention preferably have a number average primary particle size dn of 5 nm to 200 nm. Inorganic particles having a number average primary particle size dn of 5 nm to 200 nm include silica, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, antimony and tantalum-doped oxide. Fine particles such as tin and zirconium oxide can be preferably used. Among these, silica, particularly hydrophobic silica whose surface is hydrophobized is preferable from the viewpoints of cost, particle size adjustment and ease of surface treatment.

  The inorganic particles contained in the surface layer of the present invention preferably satisfy the following formula (a).

Formula (a) 0.5 <number average primary particle size dn / 90% span value Δd <0.7
By using inorganic particles having such a span value, the surface properties of the surface layer can be uniformly adjusted, and the effects of the present invention can be increased.

  The number average primary particle size of the inorganic particles of the present invention is increased 10,000 times by observation with a transmission electron microscope, 500 particles are randomly observed as primary particles, and a particle size distribution of ferret diameter is created by image analysis. The number average primary particle size dn and the 90% span value Δd are calculated. Here, the 90% span value Δd will be described with reference to FIG. As shown in FIG. 2, the 90% span value Δd is a particle size distribution curve S of inorganic particles whose vertical axis is the number of particles and horizontal axis is the particle size (nm). The difference (B−A) in the particle diameters at both ends of the region D containing 90% of the particles is shown.

  The hydrophobicity of the hydrophobic silica is preferably 50% or more in terms of the degree of hydrophobicity indicated by a measure of wettability to methanol (methanol wettability). When the degree of hydrophobicity is less than 50%, the endothermic energy change amount ΔH tends to be larger than 10 J / g, and as a result, environmental memory is likely to be generated. A more preferred degree of hydrophobicity is 65% or more, and a most preferred degree of hydrophobicity is 70% or more.

  Methanol wettability representing the degree of hydrophobicity is an evaluation of wettability of silica fine powder to methanol. The wettability is measured by the following method. 0.2 g of silica fine powder to be measured is added to 50 ml of distilled water in a beaker having an inner volume of 250 ml and stirred. Next, methanol is slowly added dropwise from a burette whose tip is immersed in the liquid until the entire silica fine powder is wetted while being slowly stirred. When the amount of methanol necessary to completely wet the silica fine powder is a (ml), the degree of hydrophobicity is calculated as follows.

Hydrophobicity = (a / (a + 50)) × 100
The hydrophobic silica can be obtained by hydrophobizing silica powder produced by a known wet method or dry method. In particular, a so-called fumed silica produced by a dry method (vapor phase oxidation of a silicon halide compound) and treated with a hydrophobizing agent is preferable because it has few moisture adsorption sites. This is manufactured by a conventionally known technique. For example, a thermal decomposition oxidation reaction of silicon tetrachloride gas in an oxyhydrogen flame is used, and the basic reaction formula is as follows.

SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl
In this production process, for example, it is also possible to obtain a composite fine powder of silica and another metal oxide by using another metal halogen compound such as aluminum chloride or titanium chloride together with a silicon halogen compound.

  Hydrophobic treatment of silica powder is carried out by spraying a hydrophobizing agent solution dissolved in alcohol, etc., or contacting a vaporized hydrophobizing agent to a cloud of silica fine powder dispersed by stirring or the like. It can be performed by a conventionally known method such as a dry treatment to be performed or a wet treatment in which silica powder is dispersed in a solution and a hydrophobizing agent is dropped and adhered therein.

  As the hydrophobizing agent, known compounds can be used, and specific examples are given below. These compounds may be used in combination.

  Examples of the titanium coupling agent include tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, and bis (dioctylpyrophosphate) oxyacetate titanate.

  Examples of silane coupling agents include γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β-vinylbenzylamino. Ethyl-N-γ-aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyl Examples include trimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, and p-methylphenyltrimethoxysilane.

  Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, and amino-modified silicone oil.

  These hydrophobizing agents are preferably added in an amount of 1 to 40% by mass with respect to the silica powder, and more preferably 3 to 30% by mass.

  A hydrogen polysiloxane compound may be used as the surface hydrophobizing agent. The hydrogen polysiloxane compound having a molecular weight of 1000 to 20000 is generally easily available, and has a good function to prevent the occurrence of black spots. In particular, when methylhydrogenpolysiloxane is used for the final surface treatment, a good effect can be obtained.

  In the present invention, the hydrophobic silica subjected to the hydrophobic treatment is included in the surface layer of the organophotoreceptor together with the binder, but the proportion of the hydrophobic silica in the surface layer is 1 to 20% by mass, preferably 2 to 15% by mass with respect to the binder. %, Most preferably 2 to 10% by weight. If it exceeds 20% by mass, environmental memory is generated, toner transferability is deteriorated, and cleaning failure is liable to occur. On the other hand, if it is less than 1% by mass, the wear resistance of the photoreceptor tends to be lowered.

  In the present invention, the inorganic fine particles in the surface layer are preferably hydrophobized, and at the same time, the water absorption of the binder resin in which these inorganic fine particles are dispersed is preferably reduced. That is, the binder resin used for the surface layer is preferably selected from binder resins having a water absorption of 0.5% or less, preferably 0.3% or less, and having substantially no hygroscopicity. As such a binder resin, resins such as polycarbonate, polyester and polyarylate are preferable, and polycarbonate having particularly good electrophotographic properties is preferable.

  Further, an antioxidant having a hindered phenol, hindered amine, thioether or phosphite partial structure can be added to the surface layer of the present invention, which is effective in improving the potential stability and image quality when the environment changes.

  Examples of the antioxidant having a hindered phenol structure include compounds described in JP-A-1-118137 (P7 to P14), but the present invention is not limited thereto.

  Examples of the antioxidant having a hindered amine structure include compounds described in JP-A-1-118138 (P7 to P9), but the present invention is not limited thereto.

  The following are examples of typical antioxidant compounds.

  Examples of the antioxidants that have been commercialized include the following compounds such as “Irganox 1076”, “Irganox 1010”, “Irganox 1098”, “Irganox 245”, “Irganox 1330”, “ "Irganox 3114", "Irganox 1076", "3,5-di-t-butyl-4-hydroxybiphenyl" or more hindered phenols, "Sanol LS2626", "Sanol LS765", "Sanol LS2626", "Sanol LS770 "," Sanol LS744 "," Tinuvin 144 "," Tinuvin 622LD "," Mark LA57 "," Mark LA67 "," Mark LA62 "," Mark LA68 "," Mark LA63 "or more hindered amine system," Smilizer TPS " , ”Smilizer P-D or higher thioether type, “Mark 2112”, “Mark PEP-8”, “Mark PEP-24G”, “Mark PEP-36”, “Mark 329K”, “Mark HP-10” or higher phosphite type Can be mentioned. Of these, hindered phenols and hindered amine antioxidants are particularly preferred. As the addition amount of the antioxidant, it is preferable to use 0.1 to 10 parts by mass with respect to 100 parts by mass of the total mass of the surface layer solids.

  As described above, if the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the general formula (1) and having a distribution based on n is x, the composition ratio of the compound of the 2-position component is y, x + y The surface layer containing the charge transport layer containing 99% or less of the mixed compound and the inorganic particles has been described. The layer structure of the electrophotographic photoreceptor other than these, particularly the layer structure of the organic photoreceptor, will be described below.

  In the present invention, the organic photoconductor means an electrophotographic photoconductor formed by providing an organic compound with at least one of a charge generation function and a charge transport function essential to the configuration of the electrophotographic photoconductor. All known organic electrophotographic photoreceptors such as a photoreceptor composed of the above organic charge generating substance or organic charge transporting substance, a photoreceptor composed of a polymer complex with a charge generating function and a charge transporting function are contained.

  The constitution of the organic photoreceptor preferably used in the present invention is described below.

Conductive Support The conductive support used for the photoreceptor may be either a sheet or a cylinder, but a cylindrical conductive support is preferred for designing an image forming apparatus compactly. .

  Cylindrical conductive support means a cylindrical support necessary for forming an endless image by rotating. Conductivity is within a range of 0.1 mm or less in straightness and 0.1 mm or less in deflection. A support is preferred. Exceeding the range of straightness and shake makes it difficult to form a good image.

As the conductive material, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide or the like, or a paper / plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ωcm or less at room temperature.

  As the conductive support used in the present invention, one having an alumite film that has been sealed on the surface thereof may be used. The alumite treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., but anodizing treatment in sulfuric acid gives the most preferable result. In the case of anodizing treatment in sulfuric acid, the sulfuric acid concentration is preferably 100 to 200 g / L, the aluminum ion concentration is 1 to 10 g / L, the liquid temperature is about 20 ° C., and the applied voltage is preferably about 20 V. It is not limited. The average film thickness of the anodized film is usually 20 μm or less, particularly preferably 10 μm or less.

Intermediate layer In the present invention, an intermediate layer having a barrier function may be provided between the conductive support and the photosensitive layer.

  In the present invention, in order to improve the adhesion between the conductive support and the photosensitive layer, or to prevent charge injection from the support, an intermediate layer (including an undercoat layer) is provided between the support and the photosensitive layer. Including) can also be provided. Examples of the material for the intermediate layer include polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more of these resin repeating units. Of these subbing resins, a polyamide resin is preferable as a resin capable of reducing the increase in residual potential due to repeated use. The film thickness of the intermediate layer using these resins is preferably 0.01 to 0.5 μm.

  Examples of the intermediate layer preferably used in the present invention include an intermediate layer using a curable metal resin obtained by thermosetting an organic metal compound such as a silane coupling agent or a titanium coupling agent. As for the film thickness of the intermediate | middle layer using curable metal resin, 0.1-2 micrometers is preferable.

  An intermediate layer preferably used in the present invention includes an intermediate layer in which inorganic particles are dispersed in a binder resin. The average particle diameter of the inorganic particles is preferably 0.01 to 1 μm. In particular, an intermediate layer in which N-type semiconductive fine particles subjected to surface treatment are dispersed in a binder is preferable. For example, an intermediate layer in which titanium oxide having an average particle size of 0.01 to 1 μm, which has been surface-treated with silica / alumina treatment and a silane compound, is dispersed in a polyamide resin. The film thickness of such an intermediate layer is preferably 1 to 20 μm.

  The N-type semiconducting fine particles are fine particles having the property of using conductive carriers as electrons. That is, the property that the conductive carrier is an electron is that the N-type semiconducting fine particles are contained in an insulating binder to effectively block hole injection from the substrate, and to convert electrons from the photosensitive layer into electrons. On the other hand, it has the property which does not show blocking property.

  Here, a method for discriminating N-type semiconductor particles will be described.

  An intermediate layer having a thickness of 5 μm is formed on the conductive support (the intermediate layer is formed using a dispersion in which 50% by mass of particles are dispersed in the binder resin constituting the intermediate layer). The intermediate layer is negatively charged and the light attenuation characteristics are evaluated. In addition, the light attenuation characteristics are similarly evaluated by charging to positive polarity.

  N-type semiconductive particles are particles that are dispersed in the intermediate layer in the above evaluation when the light attenuation when charged negatively is greater than the light attenuation when charged positively. It is called semiconductive particle.

Specific examples of the N-type semiconducting fine particles include fine particles of titanium oxide (TiO ₂ ), zinc oxide (ZnO), tin oxide (SnO ₂ ), etc. In the present invention, titanium oxide is particularly preferably used. It is done.

  The average particle diameter of the N-type semiconducting fine particles used in the present invention is preferably in the range of 10 nm to 500 nm in the number average primary particle diameter, more preferably 10 nm to 200 nm, and particularly preferably 15 nm to 50 nm. .

  The intermediate layer using N-type semiconducting fine particles whose number average primary particle size is within the above range can be finely dispersed in the layer, has sufficient potential stability, and generates black spots. Has a prevention function.

  For example, in the case of titanium oxide, the number-average primary particle size of the N-type semiconducting fine particles is magnified 10,000 times by observation with a transmission electron microscope, and 100 particles are randomly observed as primary particles. It is measured as the number average diameter.

  The shape of the N-type semiconducting fine particles used in the present invention includes dendritic, needle-like, and granular shapes. For example, in the case of titanium oxide particles, the N-type semiconductive fine particles have a crystalline form. There are anatase type, rutile type and amorphous type, but any crystal type may be used, or two or more crystal types may be mixed and used. Of these, the rutile type is the best.

  One of the hydrophobizing surface treatments performed on the N-type semiconducting fine particles is a plurality of surface treatments, and the last surface treatment is a surface treatment with a reactive organosilicon compound. Is to do. In addition, at least one of the surface treatments is at least one surface treatment selected from alumina, silica, and zirconia, and finally the surface treatment of the reactive organosilicon compound is performed. It is preferable.

  Alumina treatment, silica treatment, and zirconia treatment are treatments for depositing alumina, silica, or zirconia on the surface of the N-type semiconducting fine particles. Alumina, silica, and zirconia deposited on these surfaces include alumina, silica, Zirconia hydrates are also included. The surface treatment of the reactive organosilicon compound means using a reactive organosilicon compound in the treatment liquid.

  In this way, the surface treatment of the N-type semiconductive fine particles such as titanium oxide particles was performed at least twice, so that the surface of the N-type semiconductive fine particles was uniformly coated (treated), and the surface treatment was performed. When N-type semiconducting fine particles are used in the intermediate layer, a good photoconductor having good dispersibility of N-type semiconductive fine particles such as titanium oxide particles in the intermediate layer and causing no image defects such as black spots. You can get it.

Photosensitive layer The photosensitive layer configuration of the photoreceptor of the present invention may be a single-layer photosensitive layer configuration in which a charge generation function and a charge transport function are provided on one layer on the intermediate layer, but more preferably the function of the photosensitive layer. The charge generation layer (CGL) and the charge transport layer (CTL) may be separated from each other. By adopting a configuration in which the functions are separated, an increase in the residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negatively charged photoconductor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer and a charge transport layer (CTL) is formed thereon. In the positively charged photoconductor, the order of the layer configuration is the reverse of that in the negatively charged photoconductor. The most preferred photosensitive layer structure of the present invention is a negatively charged photoreceptor structure having the function separation structure.

  The structure of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below.

Charge generation layer The charge generation layer contains a charge generation material (CGM). Other substances may contain a binder resin and other additives as necessary.

  A known charge generation material (CGM) can be used as the charge generation material (CGM). For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azulenium pigment, or the like can be used. Among these, CGM which can minimize the increase in residual potential due to repeated use has a crystal structure capable of taking a stable aggregate structure among a plurality of molecules, specifically, a phthalocyanine pigment having a specific crystal structure, CGM of a perylene pigment is mentioned. For example, CGMs such as titanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to Cu—Kα rays and benzimidazole perylene having a maximum peak at 2θ of 12.4 have little deterioration due to repeated use. Potential increase can be reduced.

  When a binder is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin, and the like. Can be mentioned. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 μm to 2 μm.

Charge Transport Layer The charge transport layer contains a charge transport material (CTM) and a binder resin that forms a film by dispersing CTM. Other substances may contain additives such as antioxidants as necessary.

  As the charge transport material (CTM), the composition ratio of the compound of the largest component of the mixed compound having the chemical structure of the general formula (1) and having the distribution based on n is x, and the composition of the compound of the 2-position component When the ratio is y, a mixed compound having x + y of 99% or less is used. Further, together with the mixed compound, for example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound and the like can be used in combination. These charge transport materials are usually dissolved in a suitable binder resin to form a layer.

  Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, and polycarbonate. Resin, silicone resin, melamine resin, and copolymer resin containing two or more of repeating unit structures of these resins. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used.

  Most preferred as a binder for these CTLs is a polycarbonate resin. The polycarbonate resin is most preferable in improving the dispersibility and electrophotographic characteristics of CTM. The ratio of the binder resin to the charge transport material is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  The charge transport layer preferably contains the above-described antioxidant. Typical examples of the antioxidants prevent the action of oxygen on auto-oxidizing substances existing in the electrophotographic photosensitive member or on the surface of the electrophotographic photosensitive member under conditions of light, heat, and discharge. It is also a substance having a suppressing property.

  The charge transport layer may be composed of two or more layers, and the charge transport layer on the surface may have the structure of the surface layer of the present invention. The thickness of the charge transport layer is preferably 10 to 40 μm.

Protective layer As described above, an electrophotographic photosensitive member having a protective layer containing inorganic particles as a surface layer is most preferable.

  In the above, the most preferable layer structure of the photoreceptor of the present invention is exemplified, but in the present invention, a photoreceptor layer structure other than the above may be used.

  As a solvent or dispersion medium used for forming a layer such as a photosensitive layer, an intermediate layer, and a protective layer, n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methyl ethyl ketone , Methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane , Tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve, etc. And the like. Although this invention is not limited to these, Dichloromethane, 1, 2- dichloroethane, methyl ethyl ketone, etc. are used preferably. These solvents may be used alone or as a mixed solvent of two or more.

  Further, the coating solution for each layer is preferably filtered with a metal filter, a membrane filter or the like in order to remove foreign matters and aggregates in the coating solution before entering the coating step. For example, it is preferable to select a pleat type (HDC), a depth type (profile), a semi-depth type (profile star), etc., manufactured by Nippon Pole Co., Ltd. according to the characteristics of the coating solution and perform filtration.

  Next, as a coating processing method for producing the organic electrophotographic photosensitive member, a coating processing method such as dip coating, spray coating, circular amount regulation type coating, etc. is used. In order to prevent the film from being dissolved as much as possible, and in order to achieve uniform coating processing, it is preferable to use a coating processing method such as spray coating or circular amount regulation type (circular slide hopper type is a typical example). It is most preferable to use the circular amount regulation type coating method for the protective layer. The circular amount regulation type coating is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.

  Next, an image forming method and an image forming apparatus using the electrophotographic photosensitive member of the present invention will be described.

  FIG. 1 is a cross-sectional configuration diagram of an image forming apparatus as an example of the image forming method of the present invention.

  In FIG. 1, reference numeral 50 denotes a photosensitive drum (photosensitive member) which is an image bearing member, which is a photosensitive member coated with an organic photosensitive layer on the drum, and is grounded and rotated clockwise. Reference numeral 52 denotes a scorotron charger (charging means) for uniformly charging the circumferential surface of the photosensitive drum 50 by corona discharge. Prior to the charging by the charger 52, the peripheral surface of the photosensitive member may be discharged by performing exposure by the pre-charging exposure unit 51 using a light emitting diode or the like in order to eliminate the history of the photosensitive member in the previous image formation.

  After uniform charging of the photoreceptor, image exposure based on the image signal is performed by an image exposure unit 53 as an image exposure unit. The image exposure unit 53 in this figure uses a laser diode (not shown) as an exposure light source. Scanning on the photosensitive drum is performed by the light whose optical path is bent by the reflection mirror 532 through the rotating polygon mirror 531 and the fθ lens, and an electrostatic latent image is formed.

  Here, the reversal development process means that the surface of the photoreceptor is uniformly charged by the charger 52, and the exposed area of the photoreceptor, that is, the exposed area potential (exposed area) of the photoreceptor is developed by the developing process (means). This is an image forming method for visualizing. On the other hand, the unexposed portion potential is not developed by the developing bias potential applied to the developing sleeve 541.

The electrostatic latent image is then developed by a developing device 54 as developing means. A developing device 54 containing a developer composed of toner and carrier is provided on the periphery of the photosensitive drum 50, and development is performed by a developing sleeve 541 that contains a magnet and rotates while holding the developer. The inside of the developing device 54 is composed of developer agitating / conveying members 544 and 543, a conveying amount regulating member 542, and the like, and the developer is agitated and conveyed and supplied to the developing sleeve. Controlled by member 542. The developer transport amount varies depending on the linear velocity and developer specific gravity of the applied electrophotographic photosensitive member, but is generally in the range of ^{20 to} 200 mg / cm ² .

  The developer is, for example, a carrier composed of the above-mentioned ferrite as a core and coated with an insulating resin around it, and a coloring material such as carbon black, a charge control agent, and a low molecular weight polyolefin mainly composed of the above-mentioned styrene acrylic resin. The toner is composed of a toner in which silica, titanium oxide, or the like is externally added to the particles. The developer is transported to the development area with the layer thickness regulated by a transport amount regulating member, and development is performed. At this time, usually, development is performed by applying a DC bias between the photosensitive drum 50 and the developing sleeve 541 and, if necessary, an AC bias voltage. Further, the developer is developed in contact with or not in contact with the photoreceptor. The potential of the photosensitive member is measured by providing a potential sensor 547 above the development position as shown in FIG.

  The recording paper P is fed to the transfer area by the rotation operation of the paper feed roller 57 when the transfer timing is ready after the image formation.

  In the transfer area, a transfer electrode (transfer means: transfer device) 58 is operated on the peripheral surface of the photosensitive drum 50 in synchronization with the transfer timing, and the charged recording paper P is charged with a polarity opposite to that of the toner. Transfer the toner.

  Next, the recording paper P is neutralized by a separation electrode (separator) 59, separated by the peripheral surface of the photosensitive drum 50 and conveyed to the fixing device 60, and the toner is removed by heating and pressurization of the heat roller 601 and the pressure roller 602. After the welding, the sheet is discharged to the outside of the apparatus via the sheet discharge roller 61. The transfer electrode 58 and the separation electrode 59 stop the primary operation after passing through the recording paper P, and prepare for the next toner image formation. In FIG. 1, a transfer band electrode of corotron is used as the transfer electrode 58. The transfer electrode setting conditions vary depending on the process speed (peripheral speed) of the photosensitive member and cannot be specified. For example, the transfer current is set to +100 to +400 μA, and the transfer voltage is set to +500 to +2000 V. can do.

  On the other hand, after the recording paper P is separated, the photosensitive drum 50 removes and cleans residual toner by pressure contact of the blade 621 of the cleaning device (cleaning means) 62, and again performs charge removal by the pre-charge exposure unit 51 and charging by the charger 52. Then, the next image forming process is started.

  Reference numeral 70 denotes a detachable process cartridge in which a photoconductor, a charger, a transfer device, a separator, and a cleaning device are integrated.

  The electrophotographic photosensitive member of the present invention is generally applicable to electrophotographic apparatuses such as an electrophotographic copying machine, a laser printer, an LED printer, and a liquid crystal shutter printer, and further displays, recordings, light printing, plate making and the like using electrophotographic technology. It can be widely applied to apparatuses such as facsimiles.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. However, “part” in the following text indicates “part by mass”.

Example 1
A photoreceptor containing the mixed compound of the general formula A was produced as follows.
Preparation of photoreceptor 1A <intermediate layer>
Polyamide resin (Amilan CM-8000: manufactured by Toray Industries, Inc.) 60 parts Inorganic fine particles: Titanium oxide (titanium oxide having a number average primary particle size of 35 nm subjected to silica treatment, alumina treatment, and methylhydrogenpolysiloxane treatment) 180 Part Methanol 1600 parts 1-Butanol 400 parts The above components were mixed and dissolved to prepare an intermediate layer coating solution. This coating solution was applied onto a cylindrical aluminum substrate by a dip coating method, and after drying, an intermediate layer having a thickness of 1.0 μm was formed.
<Charge generation layer>
Titanyl phthalocyanine pigment (pigment with Cu-Kα characteristic X-ray diffraction spectrum, maximum peak of Bragg angle 2θ of 27.3 °) 60 parts Silicone resin solution (KR5240, 15% xylene-butanol solution: Shin-Etsu Chemical Co., Ltd.) 700 parts 2-butanone 2000 parts The above components were mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied onto the intermediate layer by a dip coating method, and after drying, a charge generation layer having a thickness of 0.3 μm was formed.
<Charge transport layer>
Charge transport material (compound of synthesis example (1)) 150 parts Binder resin: Bisphenol Z-type polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Co., Ltd.) 300 parts Antioxidant (Sanol LS2626: Sankyo Co., Ltd.) 1.7 parts Tetrahydrofuran ( Boiling point: 64.5 ° C.) 2200 parts The above components were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method and dried at 100 ° C. for 40 minutes to form a charge transport layer having a thickness of 19 μm.

<Protective layer A>
Charge transport layer material (T-1) 200 parts Polycarbonate “Iupilon Z300” (Mitsubishi Gas Chemical Co., Ltd.) 300 parts 2,6-di-tert-butyl-4-phenylphenol 5 parts Inorganic particles (octylsilane-treated silica, hydrophobic Degree of conversion: 72%, number average primary particle size (dn): 9 nm, number average primary particle size / 90% span value (dn / Δd): 0.72) 10 parts Tetrahydrofuran (boiling point: 64.5 ° C.) 2000 parts Were mixed and stirred well to prepare a coating solution. A protective layer is formed on the charge transport layer by a circular amount-regulating coating device on this coating solution, and heated and cured at 110 ° C. for 60 minutes to form a protective layer A having a dry film thickness of 5.0 μm. Produced.

Preparation of photoconductors 2A to 14A Photosensitive body 1A was photosensitized in the same manner as in photoconductor 1A, except that the charge generation material, the compound of the charge transport material in the charge transport layer, the amount of compound, the film thickness, and the protective layer were changed as shown in Table 1. Body 2A-14A was produced. However, the protective layers B to N were prepared by changing the inorganic particles and the charge transport material of the protective layer A as shown in Table 2.

Production of Photoreceptor 15A In the production of Photoreceptor 1A, n of Compound 21A (p = 0, q = 0) separately synthesized by a known method was used as the charge transport material of the charge transport layer (the compound of Synthesis Example (1)). Photoreceptor 15A was prepared in the same manner except that the charge transport material was a component having only = 0 (component purity greater than 99%).

Production of Photoreceptor 16A In production of Photoreceptor 1, the charge transport material (compound of Synthesis Example (1)) in the charge transport layer was separated from the compound of Synthesis Example (1) by liquid chromatography, and the compound 21A A photoconductor 16A was prepared in the same manner except that the charge transport material was replaced by a charge transport material having only n = 3 (component purity greater than 99%) (p = 0, q = 0). A photoconductor that could be evaluated and deposited without being compatible with the resin was not obtained.

Preparation of Photoconductor 17A In Photoconductor 1, the components of the charge transport material (1) in the charge transport layer and the compound of Synthesis Example (1) were separated by liquid chromatography to obtain compound 21A (p = 0, q = 0), a photoconductor 17A was prepared in the same manner except that the mixed compound charge transport material was mixed in which the composition ratio of n = 1 and n = 2 was 50%.

Production of Photoreceptor 18A Photoreceptor 18A having protective layer R (containing no inorganic particles) was produced in the same manner as Photoreceptor 1A except that hydrophobic silica was removed from protective layer A.

In Table 1, Y is a titanyl phthalocyanine pigment (a pigment having a maximum peak of 27.3 ° with a Bragg angle 2θ in a Cu-Kα characteristic X-ray diffraction spectrum).
Z represents a benzimidazole perylene pigment (a pigment having a maximum peak at a Bragg angle 2θ of 12.4 ° in a Cu-Kα characteristic X-ray diffraction spectrum).

  (X + y) represents the sum (in%) of the composition ratio x of the compound of the maximum component of the mixed compound of the present invention and the composition ratio y of the compound of the 2-position component.

  The distribution (composition ratio) of the chain structure n of the charge transport material was determined from the area ratio of high performance liquid chromatography. Average molecular weight Mw shows the weight average molecular weight (polystyrene conversion) calculated | required from the gel permeation chromatography (GPC).

  In Table 2, the chemical structures of charge transport materials (T-1) to (T-4) are shown below.

Evaluation Each of the photoreceptors 1A to 18A obtained as described above has a reversal development type digital copying machine "Konica 7085" (Scorotron charger, semiconductor laser image exposure device (wavelength 680 nm), and reversal development means, manufactured by Konica Corporation. The following evaluation items were evaluated. Evaluation was performed by changing environmental conditions (temperature and humidity conditions) for each evaluation item. The evaluation basically consists of an original image in which the character ratio, halftone image, solid white image, and solid black image with a pixel rate of 7% are divided into ¼ equal parts in A4 and 10,000 sheets in intermittent mode. A copy was made and evaluated. The evaluation results are shown in Table 3.

Evaluation condition Line speed: 420 mm / second Time to reach from the image exposure to the development position; 0.108 seconds Charging condition Charger; Scorotron charger (negative charge)
Charging potential: -700V to -750V
Exposure condition Set the exposure amount to make the solid black image potential -100V.

Exposure beam; Laser uses a 680 nm semiconductor laser. Development conditions The developer is a carrier coated with an insulating resin with ferrite as the core, and a styrene acrylic resin as the main materials. Colorant of carbon black, charge control agent, and low molecular weight polyolefin. A toner developer in which silica and titanium oxide were externally added to colored particles having a volume average particle size of 5.3 μm produced by a polymerization method comprising:

Transfer conditions Transfer pole; corona charging method (positive charging)
Separation conditions Cleaning conditions using the separation means of the separation claw unit A cleaning blade having a hardness of 70 °, a rebound resilience of 65%, a thickness of 2 (mm), and a free length of 9 mm is applied to the cleaning portion at a linear pressure of 18 (g / cm) It contact | abutted by the weight load system so that it might become.

Evaluation item and evaluation method High-speed response under low-temperature and low-humidity (10 ° C, 20% RH) environment (potential change in solid black image area)
In a low-temperature, low-humidity (10 ° C, 20% RH) environment, one A4 original image with a pixel rate of 7%, a halftone image, a solid white image, and a solid black image each divided into 1/4 equal intervals In this mode, 10,000 sheets were copied, and the potential change (| ΔV |) of the solid black image portion at the development position after the initial and 10,000 sheets was evaluated. The smaller | ΔV |, the better the high-speed response in a low-temperature, low-humidity (10 ° C, 20% RH) environment.

A: Potential change in solid black image portion | ΔV | is less than 50 V (good)
○: Potential change of solid black image portion | ΔV | is 50 V to 150 V (no problem in practical use)
×: The potential change | ΔV | of the solid black image portion is larger than 150 V (practically problematic)
Character thinning (under low temperature and low humidity (10 ° C, 20% RH))
An original image on which a line image having a width of 0.1 mm and 0.2 mm was printed was copied and evaluated.

◎; The reproduced image is reproduced with a line width of 75% or more of the line width of the original image (good)
○: The line width of the copied image is reproduced at 40% to 74% of the line width of the original image (a level that causes no problem in practice).
×: The line width of the copied image is 39% or less of the line width of the original image, or the line width is cut (a level causing a problem in practice).
Black spot (high temperature and high humidity (30 ℃ 80% RH))
The occurrence of black spots (spot-like spot images) on the halftone image was determined according to the following criteria.

A: No black spot nuclei were observed on the photoreceptor, and no black spots were generated even in halftone images (good).
○: Black spot nuclei are seen on the photoreceptor, but no black spots are generated in the halftone image (no problem in practical use)
X: Nuclei of black spots are observed on the photosensitive member, and black spots are also generated in the halftone image (there is a practical problem)
Periodic image defects (high temperature and high humidity (30 ° C, 80% RH)
The periodicity coincided with the period of the photoconductor, and the number of visible white defects, black spots, and streak image defects per A4 size was determined.

A: Frequency of image defects of 0.4 mm or more: All copy images are 5 / A4 or less (good)
○: Frequency of image defects of 0.4 mm or more: 1 or more of 6 / A4 or more and 10 / A4 or less (no problem in practical use)
X: Frequency of image defects of 0.4 mm or more: 11 or more A4 or more occurred (practical problem)
Crack In the environment of 30 ° C. and 80% RH, the digital copying machine Konica 7085 was turned off with the power supply turned off and left for 2 days. The members around the photoconductor are in a state where the operation is only stopped during this time, that is, the members such as the cleaning blade and the developer conveying member are kept in contact with the photoconductor. Thereafter, the surface of the photoreceptor was observed to observe the presence or absence of cracks. Moreover, image evaluation was also performed, and the presence or absence of generation of streak-like image defects due to the occurrence of cracks was also evaluated.

A: Evaluation of 100 photoconductors, no occurrence of cracks and no occurrence of streak image defects (good)
◯: 100 photoconductors were evaluated, fine cracks were generated, but no streak-like image defects were generated (a level of no problem in practical use).
X: 100 photoconductors were evaluated, and cracks and streak-like image defects were observed (practically problematic level)
Image density (low temperature and low humidity (10 ° C, 20% RH))
The image density of the solid black part was measured by reflection density using RD-918 manufactured by Macbeth. Evaluated by relative density (the density of A4 paper that has not been copied is 0.00) A: 1.2 or higher (good)
○: Less than 1.2 to 0.8 (a level with no practical problem)
×: Less than 0.8 (a level that causes practical problems)
Sharpness The sharpness of the image was evaluated by squashing characters by displaying images in both low temperature and low humidity (10 ° C., 20% RH) and high temperature, high humidity (30 ° C., 80% RH) environments. 3-point and 5-point character images were formed and evaluated according to the following criteria.

◎; 3 points and 5 points are clear and easy to read ○; 3 points are partially illegible, 5 points are clear and easily readable ×: 3 points are almost unreadable and 5 points are one Part or whole is illegible

  From Table 3, the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the general formula (1) of the present invention and the distribution based on n is represented by x, and the composition ratio of the compound of the 2-position component is represented by y. Then, the photoconductors 1A to 14A in which a mixed compound having x + y of 99% or less is used as a charge transport material and the protective layer contains inorganic particles have high-speed response under a low temperature and low humidity (10 ° C., 20% RH) environment ( (Characteristic change in solid black image area is small), so there is no character thinning under low temperature and low humidity, and there are no black spots, periodic image defects, cracks, etc., and excellent image density and sharpness Is shown. On the other hand, the photoconductor 15A using only a low molecular weight compound of n = 0 is inferior in high-speed response under a low temperature and low humidity (10 ° C., 20% RH) environment, generates thin characters, and has image density and sharpness. Has fallen. Further, in the case of the photoconductor 16A using only a high molecular weight compound of n = 3, it was poorly dissolved in the binder resin, had almost no sensitivity, and was not worthy of evaluation. In addition, the photoconductor 17A using a compound 21A (p = 0, q = 0) having a composition ratio of n = 1 and n = 2 of 50% as a charge transport material is also used as a charge transport material binder resin. Since the solubility is insufficient, the potential change in the solid black image portion is large, cracks are generated, and the image density and sharpness are lowered. In addition, the potential change in the black image portion of the photosensitive layer 18A outside the present invention is large, black spots and periodic image defects are generated, and the image density and sharpness are also lowered.

Example 2
A photoreceptor containing the mixed compound of the general formula B was produced as follows.
Preparation of photoreceptor 1B <intermediate layer>
Polyamide resin (Amilan CM-8000: manufactured by Toray Industries, Inc.) 60 parts Inorganic fine particles: Titanium oxide (titanium oxide having a number average primary particle size of 35 nm subjected to silica treatment, alumina treatment, and methylhydrogenpolysiloxane treatment) 180 Part Methanol 1600 parts 1-Butanol 400 parts The above components were mixed and dissolved to prepare an intermediate layer coating solution. This coating solution was applied onto a cylindrical aluminum substrate by a dip coating method, and after drying, an intermediate layer having a thickness of 1.0 μm was formed.
<Charge generation layer>
Titanyl phthalocyanine pigment (pigment with Cu-Kα characteristic X-ray diffraction spectrum, maximum peak of Bragg angle 2θ of 27.3 °) 60 parts Silicone resin solution (KR5240, 15% xylene-butanol solution: Shin-Etsu Chemical Co., Ltd.) 700 parts 2-butanone 2000 parts The above components were mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied onto the intermediate layer by a dip coating method, and after drying, a charge generation layer having a thickness of 0.3 μm was formed.
<Charge transport layer>
Charge transport material (Compound of Synthesis Example (4)) 150 parts Binder resin: Bisphenol Z-type polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Co., Ltd.) 300 parts Antioxidant (Sanol LS2626: Sankyo Co., Ltd.) 1.7 parts Tetrahydrofuran ( Boiling point: 64.5 ° C.) 2200 parts The above components were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method and dried at 100 ° C. for 40 minutes to form a charge transport layer having a thickness of 19 μm.

<Protective layer A>
Charge transport layer material (T-1) 200 parts Polycarbonate “Iupilon Z300” (Mitsubishi Gas Chemical Co., Ltd.) 300 parts 2,6-di-tert-butyl-4-phenylphenol 5 parts Inorganic particles (octylsilane-treated silica, hydrophobic Degree of conversion: 72%, number average primary particle size (dn): 9 nm, number average primary particle size / 90% span value (dn / Δd): 0.72) 10 parts Tetrahydrofuran (boiling point: 64.5 ° C.) 2000 parts Were mixed and stirred well to prepare a coating solution. A protective layer is formed on the charge transport layer by a circular amount-regulating coating device on the charge transport layer, and cured by heating at 110 ° C. for 60 minutes to form a protective layer A having a dry film thickness of 5.0 μm. Produced.

Preparation of photoconductors 2B to 14B Photosensitive body 1B was photosensitized in the same manner except that the charge generation material, the compound of the charge transport material in the charge transport layer, the amount of the compound, the film thickness, and the protective layer were changed as shown in Table 4. Body 2B-14B was produced. However, the protective layers B to N are the same as those in Table 2.

Production of Photoreceptor 15B In the production of Photoreceptor 1B, the charge transport material of the charge transport layer (the compound of Synthesis Example (5)) was prepared by separately preparing n = 1 of Compound 11B (m = 0) separately synthesized by a known method. Photoreceptor 15B was produced in the same manner except that the charge transport material (component purity greater than 99%) was used.

Production of Photoreceptor 16B In production of Photoreceptor 1B, the charge transport material (compound of Synthesis Example (5)) in the charge transport layer was separated from the compound of Synthesis Example (5) by liquid chromatography, and Compound 11B Photoreceptor 16B was prepared in the same manner except that the charge transport material of n = 3 only (m = 0) (component purity greater than 99%) was prepared, but the charge transport material was compatible with the binder resin. No photoconductor was obtained that could be evaluated.

Production of Photoreceptor 17B In production of Photoreceptor 1B, the charge transport material (the compound of Synthesis Example (5)) in the charge transport layer was separated from the compound of Synthesis Example (5) by liquid chromatography, and the compound 11B was separated. A photoconductor 17B was prepared in the same manner except that it was used instead of a mixed compound charge transport material in which the composition ratio of n = 2 and n = 3 of (m = 0) was 50%.

Preparation of Photoconductor 18B Photoconductor 18B having protective layer R (containing no inorganic particles) was prepared in the same manner as in Photoconductor 1B, except that hydrophobic silica was removed from protective layer A.

  In the table, Y and Z are the same as in Table 1.

  (X + y) is the same as in Table 1.

  The distribution (composition ratio) of the chain structure n of the charge transport material was determined from the area ratio of high performance liquid chromatography. Average molecular weight Mw shows the weight average molecular weight (polystyrene conversion) calculated | required from the gel permeation chromatography (GPC).

Evaluation Each of the photoreceptors 1B to 18B obtained as described above has a reversal development type digital copying machine "Konica 7085" (Scorotron charger, semiconductor laser image exposure device (wavelength 680 nm), and reversal development means, manufactured by Konica Corporation. A4 paper 85 sheets / min.) And evaluated in the same manner as in Example 1. The evaluation results are shown in Table 5.

  From Table 5, the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the general formula (1) of the present invention and the distribution based on n is represented by x, and the composition ratio of the compound of the 2-position component is represented by y. Then, the photoconductors 1B to 14B in which a mixed compound having x + y of 99% or less is used as a charge transport material and the protective layer contains inorganic particles have high-speed response in a low temperature and low humidity (10 ° C., 20% RH) environment ( (Characteristic change in solid black image area is small), so there is no character thinning under low temperature and low humidity, and there are no black spots, periodic image defects, cracks, etc., and excellent image density and sharpness Is shown. On the other hand, the photoconductor 15B using only a low molecular weight compound of n = 0 is inferior in high-speed response in a low-temperature and low-humidity (10 ° C., 20% RH) environment, generates thin characters, and has image density and sharpness. Has fallen. In addition, in the case of the photoreceptor 16B using only a high molecular weight compound of n = 3, the solubility with the binder resin was poor, and there was almost no sensitivity and the like, which was not worthy of evaluation. Further, the photoconductor 17B using a mixed compound of compound 11B (m = 0) in which the composition ratio of n = 2 and n = 3 is 50% as the charge transport material is also insoluble in the binder resin of the charge transport material. Therefore, the potential change in the solid black image portion is large, cracks are generated, and the image density and sharpness are lowered. Further, the change in potential of the black image portion where the protective layer is not the photoreceptor 18B of the present invention is large, black spots and periodic image defects are generated, and the image density and sharpness are also lowered.

Example 3
A photoreceptor containing the mixed compound of the general formula C was produced as follows.
Preparation of photoreceptor 1C <intermediate layer>
Polyamide resin (Amilan CM-8000: manufactured by Toray Industries, Inc.) 60 parts Inorganic fine particles: Titanium oxide (titanium oxide having a number average primary particle size of 35 nm subjected to silica treatment, alumina treatment, and methylhydrogenpolysiloxane treatment) 180 Part Methanol 1600 parts 1-Butanol 400 parts The above components were mixed and dissolved to prepare an intermediate layer coating solution. This coating solution was applied onto a cylindrical aluminum substrate by a dip coating method, and after drying, an intermediate layer having a thickness of 1.0 μm was formed.
<Charge generation layer>
Titanyl phthalocyanine pigment (pigment with Cu-Kα characteristic X-ray diffraction spectrum, maximum peak of Bragg angle 2θ of 27.3 °) 60 parts Silicone resin solution (KR5240, 15% xylene-butanol solution: Shin-Etsu Chemical Co., Ltd.) 700 parts 2-butanone 2000 parts The above components were mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied onto the intermediate layer by a dip coating method, and after drying, a charge generation layer having a thickness of 0.3 μm was formed.
<Charge transport layer>
Charge transport material (Compound of Synthesis Example (6)) 150 parts Binder resin: Bisphenol Z-type polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Co., Ltd.) 300 parts Antioxidant (Sanol LS2626: Sankyo Co., Ltd.) 1.7 parts Tetrahydrofuran ( Boiling point: 64.5 ° C.) 2200 parts The above components were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method and dried at 100 ° C. for 40 minutes to form a charge transport layer having a thickness of 19 μm.

<Protective layer A>
Charge transport layer material (T-1) 200 parts Polycarbonate “Iupilon Z300” (Mitsubishi Gas Chemical Co., Ltd.) 300 parts 2,6-di-tert-butyl-4-phenylphenol 5 parts Inorganic particles (octylsilane-treated silica, hydrophobic Degree of conversion: 72%, number average primary particle size (dn): 9 nm, number average primary particle size / 90% span value (dn / Δd): 0.72) 10 parts Tetrahydrofuran (boiling point: 64.5 ° C.) 2000 parts Were mixed and stirred well to prepare a coating solution. A protective layer is formed on the charge transport layer by a circular amount-regulating coating device, and the coating solution is heated and cured at 110 ° C. for 60 minutes to form a protective layer A having a dry film thickness of 5.0 μm. Produced.

Production of Photoreceptor 2C Photoreceptor 2C was produced in the same manner as in Photoreceptor 1C, except that the compound of the charge transport material in the charge transport layer was changed from the compound of Synthesis Example (6) to the compound of Synthesis Example (7).

Production of photoconductors 3C to 10C In production of photoconductor 1C, the same procedure was performed except that the charge generation material, the compound of the charge transport material of the charge transport layer, the amount of the compound, the film thickness, and the protective layer were changed as shown in Table 6. Photoconductors 3C to 10C were prepared. However, the protective layers B to N are the same as those in Table 2.

Production of Photoreceptor 11C In the production of Photoreceptor 1C, a compound in which the charge transport material of the charge transport layer (the compound of Synthesis Example (6)) was separately synthesized by a known method, a component having only n = 0 in the chemical structure 17C ( Photoreceptor 11C was prepared in the same manner except that it was used instead of a charge transport material having a component purity of greater than 99%.

Production of Photoreceptor 12C In production of Photoreceptor 1C, the charge transport material (compound of Synthesis Example (6)) in the charge transport layer was separated from the compound of Synthesis Example (6) by column chromatography, and the chemical structure Photoreceptor 12C was prepared in the same manner except that 17C was used instead of the charge transport material having only n = 5 (component purity greater than 99%), but the charge transport material was not compatible with the binder resin. As a result, the photoconductor which can be evaluated was not obtained.

Production of Photoreceptor 13C In production of Photoreceptor 1C, the charge transport material (compound of Synthesis Example (6)) in the charge transport layer was separated from the component of Synthesis Example (6) by liquid chromatography, and the chemical structure Photoreceptor 13C was prepared in the same manner except that 17C was used instead of the charge transport material of the mixed compound in which the composition ratio of n = 4 and n = 5 was 50%.

Production of Photoreceptor 14C Photoreceptor 14C having protective layer R (containing no inorganic particles) was produced in the same manner as in Photoreceptor 1C, except that hydrophobic silica was removed from protective layer A.

  In the table, Y and Z are the same as in Table 1.

  (X + y) is the same as in Table 1.

  The distribution (composition ratio) of the chain structure n of the charge transport material was determined from the area ratio of high performance liquid chromatography. Average molecular weight Mw shows the weight average molecular weight (polystyrene conversion) calculated | required from the gel permeation chromatography (GPC).

Evaluation Each of the photoreceptors 1C to 14C obtained as described above has a reversal development type digital copying machine “Konica 7085” (Scorotron charger, semiconductor laser image exposure device (wavelength 680 nm), and reversal development means, manufactured by Konica Corporation. A4 paper 85 sheets / min.) And evaluated in the same manner as in Example 1. Table 7 shows the evaluation results.

  From Table 7, the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the general formula (1) of the present invention and the distribution based on n is represented by x, and the composition ratio of the compound of the 2-position component is represented by y. Then, the photoconductors 1C to 10C in which x + y is a mixed compound of 99% or less as a charge transport material and the protective layer contains inorganic particles have high-speed response in a low temperature and low humidity (10 ° C., 20% RH) environment ( (Characteristic change in solid black image area is small), so there is no character thinning under low temperature and low humidity, and there are no black spots, periodic image defects, cracks, etc., and excellent image density and sharpness Is shown. On the other hand, the photoconductor 11C using only a low molecular weight compound of n = 1 is inferior in high-speed response in a low-temperature and low-humidity (10 ° C., 20% RH) environment, produces thin characters, and has image density and sharpness. Has also declined. Further, in the case of the photoreceptor 12C using only the compound having a high molecular weight of n = 5, the solubility with the binder resin was poor and there was almost no sensitivity, so that it was not worthy of evaluation. Further, the photosensitive member 13C using a mixed compound having a composition ratio of n = 4 and n = 5 of the chemical structure 17C of 50% as the charge transport material is also insufficiently soluble in the binder resin of the charge transport material. The solid black image portion has a large potential change, cracks are generated, and the image density and sharpness are also lowered. Further, the potential change in the black image portion of the photosensitive layer 14C outside the present invention is large, black spots and periodic image defects are generated, and the image density and sharpness are lowered.

1 is a cross-sectional configuration diagram of an image forming apparatus as an example of an image forming method of the present invention. It is a figure explaining 90% span value (DELTA) d.

Explanation of symbols

50 Photosensitive drum (photosensitive member)
DESCRIPTION OF SYMBOLS 51 Pre-charge exposure part 52 Charging device 53 Image exposure device 54 Development device 541 Development sleeve 543, 544 Developer stirring conveyance member 547 Potential sensor 57 Paper feed roller 58 Transfer electrode 59 Separation electrode (separator)
60 Fixing device 61 Paper discharge roller 62 Cleaning device 70 Process cartridge

Claims (17)

When the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the following general formula (1) and having a distribution based on n is x, and the composition ratio of the compound of the 2-position component is y, x + y is 99. % Of a mixed compound, and the surface layer contains inorganic particles.
General formula (1)
X- (CTM group) _n -Y
In the general formula (1), the CTM group is a charge transporting group, and X and Y represent a hydrogen atom, a halogen atom, or a monovalent organic group. N represents an integer of 0 to 10 (provided that both X and Y are hydrogen atoms or halogen atoms, n is an integer of 1 to 10). In the electrophotographic photosensitive member in which a charge generation layer having a charge generation material and a charge transport layer having a charge transport layer are laminated on a conductive support, the charge transport layer has a chemical structure of the general formula (1). In addition, the composition ratio of the compound of the maximum component of the mixed compound having a distribution based on n is x, and the composition ratio of the compound of the 2-position component is y. An electrophotographic photosensitive member having a surface layer containing 3. The electrophotographic photosensitive member according to claim 1, wherein x + y in the general formula (1) is in the following range.
30% ≦ x + y ≦ 99% The electrophotographic photoreceptor according to any one of claims 1 to 3, wherein the CTM group of formula (1), X, and Y have a chemical structure represented by the following formula A.

In the general formula A, Ar ₁ represents a monovalent substituted or unsubstituted aromatic group, Ar ₂ represents a divalent substituted or unsubstituted aromatic group , R _{1 to} R ₃ represent a hydrogen atom, 1 A valent substituted or unsubstituted aromatic group is shown, and A represents a divalent group containing a triarylamine group. Further, a plurality of _{Ar 1, R 1, R 2} , R 3 may be different from each other. p and q each represents an integer of 0 or 1. The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the CTM group of the general formula (1), X, and Y have a chemical structure represented by the following general formula B.

In the general formula B, Ar ₁ represents a divalent substituted, unsubstituted aromatic group, divalent furan group, or the following general formula (2), R _{1 to} R ₃ represent a hydrogen atom, and A represents B represents a divalent group containing a triarylamine group, and B represents a monovalent substituted or unsubstituted aromatic group. However, a plurality of B, R ₁ , R ₂ and R ₃ may be different from each other. Each m represents an integer of 0 or 1.

In general formula (2), Y is a single bond. The divalent group containing triarylamine groups of A, electrophotographic photosensitive member according to claim 4 or 5, characterized in that a group of the following general formula (4).

In the general formula (4), Ar ₃ represents a substituted or unsubstituted monovalent aromatic group. The electrophotographic photosensitive member according to claim 6 , wherein Ar ₃ is a group of the following general formula (5) .

In General Formula (5), R ₃₁ , R ₃₂ , R ₃₃ , R ₃₄ , and R ₃₅ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. However, at least one of R ₃₁ and R ₃₅ is an alkyl group having 1 to 4 carbon atoms. 6. The electrophotographic photosensitive member according to claim 4, wherein the divalent group containing a triarylamine group of A is a group of the following general formula (6) .

In General Formula (6), X ₂ represents a single bond, and Ar ₄ and Ar ₅ represent a substituted or unsubstituted monovalent aromatic group. 6. The electrophotographic photosensitive member according to claim 5 , wherein B is a group represented by the following general formula (7) .

In General Formula (7), R ₄₁ , R ₄₂ , R ₄₃ , R ₄₄ , R ₄₅ , R ₅₁ , R ₅₂ , R ₅₃ , R ₅₄ , and R ₅₅ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. . However, at least one of R ₄₁ , R ₄₅ , R ₅₁ and R ₅₅ is an alkyl group having 1 to 4 carbon atoms. The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the CTM group of the general formula (1), X, and Y have a chemical structure represented by the following general formula C.

In the general formula C, Ar ₁ represents a monovalent substituted or unsubstituted aromatic group, Ar ₂ is a divalent substituted or unsubstituted aromatic group, a divalent heterocyclic group, or the following general formula (8) R represents a monovalent substituted or unsubstituted aromatic group. However, the plurality of Ar ₁ , Ar ₂ , and R may be different from each other.

In general formula (8), Y is an oxygen atom. However, R ₁ and R ₂ are hydrogen atoms. The electrophotographic photosensitive member according to claim 1, wherein the inorganic particles have a number average primary particle size dn of 5 nm to 200 nm . The electrophotographic photosensitive member according to claim 1, wherein the inorganic particles satisfy the following formula (a) .
Formula (a) 0.5 <number average primary particle size dn / 90% span value Δd <0.7 The electrophotographic photosensitive member according to any one of claims 1 to 12, wherein the inorganic particles are characterized by being strained facilities to hydrophobic surface treatment. The electrophotographic photosensitive member according to any one of claims 1 to 12 , wherein the inorganic particles are hydrophobic silica . Assuming that the composition ratio of the compound of the maximum component of the mixed compound having the chemical structure of the general formula (1) and having a distribution based on n is x, the composition ratio of the compound of the 2-position component is y, x + y is 99. % Of a mixed compound and a surface layer containing inorganic particles, a charging means for uniformly charging the electrophotographic photosensitive member, and an electrostatic latent image on the charged electrophotographic photosensitive member A latent image forming means for forming a toner image, a developing means for visualizing an electrostatic latent image on the electrophotographic photosensitive member, and a transfer means for transferring a toner image visualized on the electrophotographic photosensitive member onto a transfer material And at least one of a charge removing means for removing the charge on the electrophotographic photosensitive member after transfer and a cleaning means for removing the residual toner on the electrophotographic photosensitive member after transfer. It is characterized by being detachably attachable to the forming device body Process cartridge that. Charging means for uniformly charging the electrophotographic photosensitive member, latent image forming means for forming an electrostatic latent image on the charged electrophotographic photosensitive member, and developing the electrostatic latent image on the electrophotographic photosensitive member In an image forming apparatus having a developing unit and a transfer unit that transfers a toner image visualized on the electrophotographic photosensitive member onto a transfer material, the electrophotographic photosensitive member has a chemical structure represented by the general formula (1). X + y is 99% or less, and the composition ratio of the compound of the maximum component of the mixed compound having a distribution based on n is x, and the composition ratio of the compound of the 2-position component is y, and the surface An image forming apparatus, wherein the layer contains inorganic particles. An image forming method comprising forming an electrophotographic image using the image forming apparatus according to claim 16.

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