JP4973196B2 - Electrophotographic photosensitive member, electrophotographic photosensitive member cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member, an electrophotographic photosensitive member cartridge, and an image forming apparatus used for a copying machine, a printer, and the like. Specifically, the present invention relates to an electrophotographic photosensitive member, an electrophotographic photosensitive member cartridge, and an image forming apparatus that have excellent wear resistance and good electrical characteristics.

  The electrophotographic technique is widely used in the fields of copiers, various printers, printing machines, etc. because it is excellent in immediacy and provides high-quality images. As an electrophotographic photoreceptor that is the core of electrophotographic technology, an electrophotographic photoreceptor using an organic photoconductive material (hereinafter simply referred to as “photosensitive material”) that has advantages such as non-pollution, easy film formation, and easy manufacture. Also referred to as "body").

  As an electrophotographic photoreceptor using an organic photoconductive material, a so-called dispersion type single-layer photoreceptor in which a photoconductive fine powder is dispersed in a binder resin, a charge generation layer and a charge transport layer are laminated. Multilayer photoreceptors are known. Multilayered photoreceptors can be obtained by combining highly efficient charge generating materials and charge transporting materials to obtain highly sensitive photoreceptors, a wide range of materials to be selected, and highly safe photoreceptors. It is the mainstream of photoconductors because it can be easily formed by coating, has high productivity and is advantageous in terms of cost, and has been developed and put into practical use.

  On the other hand, the single-layer type photoconductor is slightly inferior to the laminated type photoconductor in terms of electrical characteristics and has a somewhat lower degree of freedom in material selection, but it can generate charges near the surface of the photoconductor, increasing the resolution. In addition, there is an advantage that a high printing durability can be achieved by increasing the thickness of the film because the image is not blurred even if the thickness is increased. In addition, the single-layer type photoreceptor requires fewer coating processes, and is advantageous for interference fringes and tube defects derived from a conductive substrate (support), and can use an inexpensive substrate such as a non-cutting tube. For this reason, there is an advantage that the cost can be reduced.

  Since the electrophotographic photosensitive member is repeatedly used in an electrophotographic process, that is, a cycle of charging, exposure, development, transfer, cleaning, static elimination, etc., it is deteriorated by various stresses during that time. Such deterioration includes, for example, strong oxidative ozone and NOx generated from a corona charger used as a charger, which gives chemical damage to the photosensitive layer, and carriers generated by image exposure and static elimination light. There are chemical degradation and electrical degradation in which the photosensitive layer composition flows and the photosensitive layer composition is decomposed by light from the outside. In addition, as other degradation, abrasion or scratches on the surface of the photosensitive layer or peeling of the film may occur due to rubbing of the cleaning blade, magnetic brush, etc., contact with the developer, transfer member or paper, etc. There is mechanical deterioration. In particular, such damage on the surface of the photosensitive layer tends to appear on the image and directly impairs the image quality, which is a major factor limiting the life of the photoreceptor. In other words, in order to develop a long-life photoreceptor, it is essential to increase the mechanical strength as well as the electrical durability and chemical durability.

  In the case of a general photoreceptor not having a functional layer such as a surface protective layer, it is the photosensitive layer that receives the load of the deterioration factors as described above. The photosensitive layer usually has a binder resin and a photoconductive material. It is the binder resin that substantially determines the strength of the photosensitive layer. However, since the photoconductive material has a large amount of doping, the photosensitive layer has not yet been given sufficient mechanical strength.

  In addition, due to the increasing demand for high-speed printing, materials for a higher-speed electrophotographic process are required. In this case, in addition to high sensitivity and long life, the photosensitive member must have good responsiveness because the time from exposure to development is shortened. The responsiveness of the photoreceptor is governed by the charge transport layer, especially the charge transport material, but is known to vary greatly depending on the binder resin.

  In addition, each layer constituting these electrophotographic photoreceptors usually includes a coating liquid containing a photoconductive material and a binder resin on a support, dip coating, spray coating, nozzle coating, bar coating, roll coating, It is formed by coating by blade coating or the like. In these layer forming methods, known methods such as coating as a coating solution obtained by dissolving a material contained in a layer in a solvent are applied. In many processes, a coating solution is prepared in advance and stored. For this reason, the binder resin is required to have excellent solubility in the solvent used in the coating process and to have stability of the coating solution after dissolution.

  Examples of the binder resin for the photosensitive layer include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, thermoplastic resins such as polycarbonate, polyester, polysulfone, phenoxy, epoxy, and silicone resin, and various kinds of heat. A curable resin is used. Among the various binder resins, the polycarbonate resin has a relatively excellent performance, and various polycarbonate resins have been developed and put to practical use (for example, see Patent Documents 1 to 4).

  On the other hand, a technique of an electrophotographic photoreceptor using a polyarylate resin marketed under the trade name “U-polymer” as a binder resin is disclosed. Among them, the polyarylate resin is particularly sensitive compared to a polycarbonate resin. Is excellent (see, for example, Patent Document 5).

Also disclosed is a technique for an electrophotographic photoreceptor using a polyarylate resin using a bisphenol component having a specific structure as a binder resin, which improves solution stability during manufacture of the photoreceptor, mechanical strength, particularly abrasion resistance. It is known that the wear resistance is excellent (see, for example, Patent Documents 6 and 7).
JP 50-98332 A JP 59-71057 A JP 59-184251 JP-A-5-21478 JP-A-56-135844 Japanese Patent Laid-Open No. 3-6567 Japanese Patent Laid-Open No. 10-288845

  Conventional photoreceptors may be worn or scratched by practical loads such as toner development, transfer member or paper friction, and cleaning member (blade) friction. And so on. For this reason, the current state of the art is that the conventional photoreceptors have practically limited printing performance.

  In addition, in the electrophotographic photosensitive member using a conventionally known polyester resin as the binder resin of the photosensitive layer, the strength and the like are improved, but the photosensitive layer forming coating solution containing the polyester resin is poor in stability and becomes cloudy. There are problems such as precipitation and insolubilization. In addition, it is difficult to select a charge transport material for the photosensitive layer containing the polyester resin, and it is extremely difficult to develop sufficient electrical characteristics.

  The present invention has been made to solve such problems. That is, an object of the present invention is to provide an electrophotographic photoreceptor having high stability of a coating solution for forming a photosensitive layer, excellent wear resistance against practical loads, high mechanical strength, and extremely good electrical characteristics. It is to provide. Still another object is to provide an electrophotographic photosensitive member cartridge and an image forming apparatus having such an electrophotographic photosensitive member.

  As a result of intensive studies, the inventors of the present invention have sufficient mechanical properties by including a polyester resin having a specific structure in the photosensitive layer, and further, with respect to the solvent used in the coating solution for forming the photosensitive layer. It has been found that a charge transport material having a hydrazone structure has high solubility and excellent coating solution stability and is very compatible with the polyester resin in terms of electrical characteristics, and the present invention has been completed. .

That is, the gist of the present invention is that, in an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support, the photosensitive layer includes a polyester resin having a repeating structure represented by the following general formula (1) , and the following general formula: The electrophotographic photosensitive member is characterized by containing the hydrazone compound represented by (3) in the same layer .

(In General Formula (1), Ar ¹ and Ar ² each independently represent a phenylene group which may have a substituent, Ar ³ and Ar ⁴ each represent a phenylene group, and X ¹ has a substituent . Represents an optionally substituted alkylene group.)

(In General Formula (3), Ar ^{9 to} Ar ¹² each independently represent a phenyl group which may have an alkyl group having 3 or less carbon atoms, and Ar ¹³ has an alkyl group having 3 or less carbon atoms. Represents an optional phenylene group.)

（一般式（２）中、Ａｒ ^５ 、Ａｒ ^６ はそれぞれ独立に置換基を有していてもよいフェニレン基を表し、Ａｒ ^７ 、Ａｒ ^８ はフェニレン基を表す。Ｒ^１は水素原子又はアルキル基を表す。） The gist of the present invention resides in that the polyester resin is a polyester resin including a repeating structure represented by the following general formula (2).

(In general formula (2), Ar ⁵ and Ar ⁶ each independently represent a phenylene group which may have a substituent, Ar ⁷ and Ar ⁸ each represent a phenylene group, and R ¹ represents a hydrogen atom or an alkyl group. Represents.)

  The gist of the present invention resides in an electrophotographic photosensitive member cartridge and an image forming apparatus provided with the electrophotographic photosensitive member of the present invention.

  According to the present invention, it is possible to obtain an electrophotographic photosensitive member having excellent wear resistance and extremely excellent electrical characteristics. In the present invention, since the photosensitive layer is formed with a photosensitive layer forming coating solution containing a polyester resin having a specific structure and a hydrazone compound as a charge transporting material, the stability of the photosensitive layer forming coating solution is improved. Good properties.

  Hereinafter, the best mode for carrying out the present invention will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

[Electrophotographic photoreceptor]
The electrophotographic photosensitive member of the present invention has at least a photosensitive layer on a conductive support, the photosensitive layer contains a polyester resin having a repeating structure represented by the following general formula (1), and further contains a hydrazone compound. Contains. The polyester resin contained in the photosensitive layer is used as a binder resin, and the hydrazone compound is used as a charge transport material. In the following general formula (1), Ar ^{1 to} Ar ⁴ each independently represent an arylene group which may have a substituent, and X ¹ represents a single bond or a divalent group.

  As a specific configuration of the photosensitive layer, a multilayer type in which a charge generation layer mainly composed of a charge generation material and a charge transport layer mainly composed of a charge transport material and a binder resin are laminated on a conductive support. Typical examples include a photosensitive layer and a dispersion type (single layer type) photosensitive layer in which a charge generation material is dispersed in a layer containing a charge transport material and a binder resin on a conductive support. In the present invention, the polyester resin represented by the above general formula (1) and the hydrazone compound are usually used in the same layer constituting the photosensitive layer, and preferably the charge transport layer constituting the multilayer photosensitive layer. include.

(Polyester resin)
First, the polyester resin will be described. The polyester resin contained in the photosensitive layer contains a repeating structure represented by the general formula (1), and can be produced by a known method, for example, with a divalent hydroxyaryl component and a dicarboxylic acid component.

In General Formula (1), Ar ^{1 to} Ar ⁴ may be the same or different, and each independently represents an arylene group that may have a substituent. X ¹ represents a single bond or a divalent group. The arylene group is not particularly limited, but is preferably an arylene group having 6 to 20 carbon atoms, and examples thereof include a phenylene group, a naphthylene group, an anthrylene group, a phenanthrylene group, and a pyrenylene group. Among these, a phenylene group and a naphthylene group are particularly preferable from the viewpoint of production cost. Further, when a phenylene group and a naphthylene group are compared, a phenylene group is more preferable in terms of ease of synthesis in addition to manufacturing cost.

The substituent that may be independently present in the arylene group is not particularly limited, and preferred examples include a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, a condensed polycyclic group, and a halogen group. Considering the mechanical properties as the binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the aryl group is preferably a phenyl group or a naphthyl group, and the halogen group is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. The alkoxy group is preferably a methoxy group, an ethoxy group, or a butoxy group. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and 1 to 2 carbon atoms. Are particularly preferable, and specifically, a methyl group is most preferable. The number of substituents for each of Ar ^{1 to} Ar ⁴ is not particularly limited, but is preferably 3 or less, more preferably 2 or less, and particularly preferably 1 or less.

Further, in the general formula (1), Ar ¹ and Ar ² are preferably the same arylene group having the same substituent, and particularly preferably a phenylene group having a methyl group as a substituent. Ar ³ and Ar ⁴ are preferably the same arylene group, and particularly preferably a phenylene group having no substituent.

In General Formula (1), X ¹ represents a single bond or a divalent group, and examples of the divalent group include a sulfur atom, an oxygen atom, a sulfinyl group, a sulfonyl group, a cycloalkylene group, and —CR ² R ³ —. Is mentioned. R ² and R ³ each independently represents a hydrogen atom, an alkyl group, an aryl group, a halogen group, or an alkoxy group. Considering the mechanical properties as the binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the aryl group is preferably a phenyl group or a naphthyl group, and the halogen group is a fluorine atom, a chlorine atom, a bromine atom, An iodine atom is preferable, and an alkoxy group is preferably a methoxy group, an ethoxy group, or a butoxy group. Moreover, as an alkyl group, a C1-C10 alkyl group is preferable, More preferably, it is C1-C8, Most preferably, it is C1-2. Taking into account the simplicity of the production of the divalent hydroxyaryl component used in producing the polyester resin, X ^{1 can} be represented by —O—, —S—, —SO—, —SO ₂ —, —CO—, —CH. _2- , —CH (CH ₃ ) —, —C (CH ₃ ) ₂ —, and cyclohexylene are preferable, and —CH ₂ —, —CH (CH ₃ ) —, —C (CH ₃ ) ₂ — are more preferable. And cyclohexylene, particularly preferably —CH ₂ — and —CH (CH ₃ ) —.

In the present invention, the polyester resin is preferably a polyester resin including a repeating structure represented by the following general formula (2). In the following general formula (2), Ar ^{5 to} Ar ⁸ each independently represent an arylene group which may have a substituent, and R ¹ represents a hydrogen atom or an alkyl group.

In the general formula (2), Ar ^{5 to} Ar ⁸ correspond to the Ar ^{1 to} Ar ⁴ , respectively, and particularly preferably a phenylene group which may have a substituent. Moreover, as a preferable substituent, it is a hydrogen atom or an alkyl group, Most preferably, it is a methyl group. Furthermore, in the general formula (2), Ar ⁵ and Ar ⁶ are the same phenylene group having a methyl group, and Ar ⁷ and Ar ⁸ are particularly preferably phenylene groups having no substituent. R ¹ represents a hydrogen atom or an alkyl group, and the alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably a methyl group. .

  The divalent hydroxyaryl component to be a divalent hydroxyaryl residue in the polyester resin is represented by the following general formula (4), but is preferably represented by the following general formula (5).

In General Formula (4), Ar ¹ and Ar ² independently represent an arylene group which may have a substituent, and X ¹ represents a single bond or a divalent group. Ar ¹ , Ar ² and X ¹ are as described above.

In General Formula (5), Ar ⁵ and Ar ⁶ independently represent a phenylene group which may have a substituent, and R ¹ represents a hydrogen atom or a methyl group. Ar ⁵ , Ar ⁶ and R ¹ are as described above.

Specifically, when R ¹ in the general formula (5) is a hydrogen atom, bis (2-hydroxyphenyl) methane, (2-hydroxyphenyl) (3-hydroxyphenyl) methane, (2-hydroxyphenyl) ( 4-hydroxyphenyl) methane, bis (3-hydroxyphenyl) methane, (3-hydroxyphenyl) (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) methane, bis (2-hydroxy-3-methylphenyl) Methane, bis (2-hydroxy-3-ethylphenyl) methane, (2-hydroxy-3-methylphenyl) (3-hydroxy-4-methylphenyl) methane, (2-hydroxy-3-ethylphenyl) (3- Hydroxy-4-ethylphenyl) methane, (2-hydroxy-3-methylphenyl) (4-hydroxy -3-methylphenyl) methane, (2-hydroxy-3-ethylphenyl) (4-hydroxy-3-ethylphenyl) methane, bis (3-hydroxy-4-methylphenyl) methane, bis (3-hydroxy-4) -Ethylphenyl) methane, (3-hydroxy-4-methylphenyl) (4-hydroxy-3-methylphenyl) methane, (3-hydroxy-4-ethylphenyl) (4-hydroxy-3-ethylphenyl) methane, Examples include bis (4-hydroxy-3-methylphenyl) methane and bis (4-hydroxy-3-ethylphenyl) methane. When R ¹ is a methyl group, 1,1-bis (2-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) -1- (3-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) ) -1- (4-hydroxyphenyl) ethane, 1,1-bis (3-hydroxyphenyl) ethane, 1- (3-hydroxyphenyl) -1- (4-hydroxyphenyl) ethane, 1,1-bis ( 4-hydroxyphenyl) ethane, 1,1-bis (2-hydroxy-3-methylphenyl) ethane, 1,1-bis (2-hydroxy-3-ethylphenyl) ethane, 1- (2-hydroxy-3-) Methylphenyl) -1- (3-hydroxy-4-methylphenyl) ethane, 1- (2-hydroxy-3-ethylphenyl) -1- (3-hydroxy-4-ethylphenyl) Enyl) ethane, 1- (2-hydroxy-3-methylphenyl) -1- (4-hydroxy-3-methylphenyl) ethane, 1- (2-hydroxy-3-ethylphenyl) -1- (4-hydroxy) -3-ethylphenyl) ethane, 1,1-bis (3-hydroxy-4-methylphenyl) ethane, 1,1-bis (3-hydroxy-4-ethylphenyl) ethane, 1- (3-hydroxy-4) -Methylphenyl) -1- (4-hydroxy-3-methylphenyl) ethane, 1- (3-hydroxy-4-ethylphenyl) -1- (4-hydroxy-3-ethylphenyl) ethane, 1,1- Bis (4-hydroxy-3-methylphenyl) ethane and 1,1-bis (4-hydroxy-3-ethylphenyl) ethane are mentioned.

  Of these, bis (4-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane, and bis (2-hydroxyphenyl) methane are considered in consideration of the ease of production of the divalent hydroxyaryl component. Bis (4-hydroxy-3-methylphenyl) methane and bis (4-hydroxy-3-ethylphenyl) methane are particularly preferable, and a combination of a plurality of these divalent hydroxyaryl components can also be used.

When R ¹ in the general formula (5) is a methyl group, 1,1-bis (4-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) -1- (4-hydroxyphenyl) ethane 1,1-bis (2-hydroxyphenyl) ethane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, and 1,1-bis (4-hydroxy-3-ethylphenyl) ethane are particularly preferable. A combination of a plurality of these divalent hydroxyaryl components can also be used.

  Although general formula (5) is contained in general formula (4), the compound of general formula (4) other than the illustration of the said general formula (5) is also demonstrated below.

  Specific examples of the divalent hydroxyaryl component represented by the general formula (4) include 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl, 2,4,3 ′, 5 ′. -Tetramethyl-3,4'-dihydroxybiphenyl, 2,2 ', 4,4'-tetramethyl-3,3'-dihydroxybiphenyl, bis (4-hydroxy-3,5-dimethylphenyl) ether, (4 -Hydroxy-3,5-dimethylphenyl) (3-hydroxy-2,4-dimethylphenyl) ether, bis (3-hydroxy-2,4-dimethylphenyl) ether, bis (4-hydroxy-3,5-dimethyl) Phenyl) methane, (4-hydroxy-3,5-dimethylphenyl) (3-hydroxy-2,4-dimethylphenyl) methane, bis (3-hydroxy-2,4- Methylphenyl) methane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) ethane, 1- (4-hydroxy-3,5-dimethylphenyl) -1- (3-hydroxy-2,4- Dimethylphenyl) ethane, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) ethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2- (4-hydroxy-) 3,5-dimethylphenyl) -2- (3-hydroxy-2,4-dimethylphenyl) propane, 2,2-bis (3-hydroxy-2,4-dimethylphenyl) propane, 1,1-bis (4 -Hydroxy-3,5-dimethylphenyl) cyclohexane, 1- (4-hydroxy-3,5-dimethylphenyl) -1- (3-hydroxy-2,4-dimethylpheny ) Cyclohexane, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) cyclohexane, preferably 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl, bis (4-hydroxy-3,5-dimethylphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) ethane, 2, 2-bis (4-hydroxy-3,5-dimethylphenyl) propane and 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane. Alternatively, bis (2-hydroxyphenyl) ether, (2-hydroxyphenyl) (3-hydroxyphenyl) ether, (2-hydroxyphenyl) (4-hydroxyphenyl) ether, bis (3-hydroxyphenyl) ether, (3 -Hydroxyphenyl) (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) ether, bis (2-hydroxy-3-methylphenyl) ether, bis (2-hydroxy-3-ethylphenyl) ether, (2- Hydroxy-3-methylphenyl) (3-hydroxy-4-methylphenyl) ether, (2-hydroxy-3-ethylphenyl) (3-hydroxy-4-ethylphenyl) ether, (2-hydroxy-3-methylphenyl) ) (4-Hydroxy-3-methylphenyl) Ether, (2-hydroxy-3-ethylphenyl) (4-hydroxy-3-ethylphenyl) ether, bis (3-hydroxy-4-methylphenyl) ether, bis (3-hydroxy-4-ethylphenyl) ether, (3-hydroxy-4-methylphenyl) (4-hydroxy-3-methylphenyl) ether, (3-hydroxy-4-ethylphenyl) (4-hydroxy-3-ethylphenyl) ether, bis (4-hydroxy- 3-methylphenyl) ether, bis (4-hydroxy-3-ethylphenyl) ether, bis (4-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane, bis (2- Hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) ether, bis (4-hydroxy -3-methylphenyl) methane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4- Hydroxy-3-methylphenyl) cyclohexane, bis (4-hydroxy-3-methylphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,5) -Dimethylphenyl) ethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane and the like.

  Among these, bis (4-hydroxy-3,5-dimethylphenyl) methane and 2,2-bis (4-hydroxy-3,5-dimethylphenyl) are considered in consideration of the ease of production of the divalent hydroxyaryl component. Propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, or bis (4-hydroxyphenyl) ether, (2-hydroxyphenyl) (4-hydroxyphenyl) ether, bis (2- Hydroxyphenyl) ether, bis (4-hydroxy-3-methylphenyl) ether, and bis (4-hydroxy-3-ethylphenyl) ether are particularly preferable, and a combination of a plurality of these divalent hydroxyaryl components can be used. is there.

  The dicarboxylic acid component which is a dicarboxylic acid residue in the polyester resin is represented by the following general formula (6) or (7).

In general formula (6), Ar ³ and Ar ⁴ each independently represent an arylene group which may have a substituent. In general formula (7), Ar ⁷ and Ar ⁸ also have a substituent independently. An arylene group which may be substituted, particularly preferably a phenylene group which may have a substituent. Ar ³ , Ar ^4, Ar ⁷ , and Ar ⁸ are as described above, and are omitted here.

  Specific examples of the dicarboxylic acid residue include diphenyl ether-2,2′-dicarboxylic acid residue, diphenyl ether-2,3′-dicarboxylic acid residue, diphenyl ether-2,4′-dicarboxylic acid residue, diphenyl ether-3, 3'-dicarboxylic acid residues, diphenyl ether-3,4'-dicarboxylic acid residues, diphenyl ether-4,4'-dicarboxylic acid residues and the like can be mentioned. Among these, considering the simplicity of production of the dicarboxylic acid component, diphenyl ether-2,2′-dicarboxylic acid residue, diphenyl ether-2,4′-dicarboxylic acid residue, diphenyl ether-4,4′-dicarboxylic acid Residues are preferred, and diphenyl ether-4,4′-dicarboxylic acid residues are particularly preferred.

  The polyester resin may be a resin that contains another dicarboxylic acid component and includes the general formula (1) in a part of the structure. Specific examples of other dicarboxylic acid residues include adipic acid residues, suberic acid residues, sebacic acid residues, phthalic acid residues, isophthalic acid residues, terephthalic acid residues, toluene-2,5-dicarboxylic acid Residue, p-xylene-2,5-dicarboxylic acid residue, pyridine-2,3-dicarboxylic acid residue, pyridine-2,4-dicarboxylic acid residue, pyridine-2,5-dicarboxylic acid residue, pyridine -2,6-dicarboxylic acid residue, pyridine-3,4-dicarboxylic acid residue, pyridine-3,5-dicarboxylic acid residue, naphthalene-1,4-dicarboxylic acid residue, naphthalene-2,3-dicarboxylic acid An acid residue, naphthalene-2,6-dicarboxylic acid residue, biphenyl-2,2′-dicarboxylic acid residue, biphenyl-4,4′-dicarboxylic acid residue, preferably adipic acid residue, SE Silic acid residue, phthalic acid residue, isophthalic acid residue, terephthalic acid residue, naphthalene-1,4-dicarboxylic acid residue, naphthalene-2,6-dicarboxylic acid residue, biphenyl-2,2′-dicarboxylic acid An acid residue and a biphenyl-4,4′-dicarboxylic acid residue, particularly preferably an isophthalic acid residue and a terephthalic acid residue. A combination of a plurality of these dicarboxylic acid residues can also be used. .

  In addition, when it has the dicarboxylic acid residue constituting the present invention and the other dicarboxylic acid residues described above, the dicarboxylic acid residue constituting the present invention is preferably 70% or more as the number of repeating units, 80% or more is more preferable, and 90% or more is particularly preferable. Most preferably, it has only the dicarboxylic acid residue constituting the present invention, that is, the case where the dicarboxylic acid residue constituting the present invention is 100% as the number of repeating units.

  The polyester resin constituting the present invention can be mixed with other resins and used for an electrophotographic photosensitive member. Other resins used here include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, polycarbonate, polyester, polyester polycarbonate, polysulfone, phenoxy, epoxy, silicone resin, etc. Examples thereof include a plastic resin and various thermosetting resins. Of these resins, polycarbonate resin is preferable.

  The mixing ratio of the resin to be used in combination is not particularly limited, but in order to sufficiently obtain the effects of the present invention, it is preferable to use the resin in a range not exceeding the ratio of the polyester resin of the present invention, particularly in combination with other resins. Preferably not.

(Production method of polyester resin)
Next, the manufacturing method of the polyester resin which has a repeating structure represented by General formula (1) or (2) is demonstrated. As a method for producing the polyester resin, a known polymerization method can be used. Examples thereof include an interfacial polymerization method, a melt polymerization method, and a solution polymerization method.

  For example, when the polyester resin is produced by an interfacial polymerization method, a solution in which a divalent hydroxyaryl component is dissolved in an alkaline aqueous solution and a halogenated hydrocarbon solution in which an aromatic dicarboxylic acid chloride component is dissolved are mixed. At this time, a quaternary ammonium salt or a quaternary phosphonium salt may be present as a catalyst. The polymerization temperature is preferably in the range of 0 to 40 ° C., and the polymerization time is preferably in the range of 2 to 20 hours from the viewpoint of productivity. After completion of the polymerization, the water phase and the organic phase are separated, and the polymer dissolved in the organic phase is washed and recovered by a known method to obtain the intended resin.

  Examples of the alkali component used in the interfacial polymerization method include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. As the usage-amount of an alkali, the range of 1.01-3 times equivalent of the phenolic hydroxyl group contained in a reaction system is preferable. Examples of the halogenated hydrocarbon include dichloromethane, chloroform, 1,2-dichloroethane, trichloroethane, tetrachloroethane, dichlorobenzene and the like. The quaternary ammonium salt or quaternary phosphonium salt used as a catalyst includes salts of tertiary alkylamines such as tributylamine and trioctylamine such as hydrochloric acid, bromic acid, iodic acid, benzyltriethylammonium chloride, benzyltrimethylammonium chloride, Examples include benzyltributylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, trioctylmethylammonium chloride, tetrabutylphosphonium bromide, triethyloctadecylphosphonium bromide, N-laurylpyridinium chloride, laurylpicolinium chloride and the like.

  In the interfacial polymerization method, a molecular weight regulator can be used. Examples of the molecular weight regulator include phenol, o, m, p-cresol, o, m, p-ethylphenol, o, m, p-propylphenol, o, m, p- (tert-butyl) phenol, and pentyl. Alkylphenols such as phenol, hexylphenol, octylphenol, nonylphenol, 2,6-dimethylphenol derivatives and 2-methylphenol derivatives, monofunctional phenols such as o, m, p-phenylphenol, acetic acid chloride, butyric acid chloride, octyl Examples thereof include monofunctional acid halides such as acid chloride, benzoyl chloride, benzenesulfonyl chloride, benzenesulfinyl chloride, sulfinyl chloride, benzenephosphonyl chloride, and substituted products thereof. Among these molecular weight regulators, o, m, p- (tert-butyl) phenol, 2,6-dimethylphenol derivatives, and 2-methylphenol derivatives are preferred because of their high molecular weight controllability and solution stability. And particularly preferred are p- (tert-butyl) phenol, 2,3,6-tetramethylphenol, and 2,3,5-tetramethylphenol.

  In the polyester resin having a repeating structure represented by the general formula (1) or (2), the viscosity average molecular weight is usually 10,000 or more, preferably 15,000 so as to be suitable for coating and forming a photosensitive layer. More preferably, it is 20,000 or more, usually 300,000 or less, preferably 200,000 or less, more preferably 100,000 or less. If the viscosity average molecular weight is less than 10,000, the mechanical strength of the resin is lowered and is not practical, and if it is 300,000 or more, it is difficult to coat and form the photosensitive layer to an appropriate film thickness.

  The above-described polyester resin is used in an electrophotographic photoreceptor, and is used as a binder resin in a photosensitive layer provided on a conductive support of the photoreceptor.

(Hydrazone compound)
Next, the hydrazone compound will be described. In the present invention, the hydrazone compound contained in the photosensitive layer of the electrophotographic photosensitive member is included as a charge transport material, but functions as an electrophotographic photosensitive member and can form an image using the electrophotographic photosensitive member. If it is, it will not specifically limit about the kind of hydrazone compound, Various hydrazone compounds can be used. Of these, hydrazone compounds having a molecular weight of 350 to 800 are preferred, and hydrazone compounds having a molecular weight of 450 to 650 are more preferred. As an example of the hydrazone compound, a hydrazone compound represented by the structure of the following general formula (3) can be preferably exemplified.

In general formula (3), Ar ⁹ and Ar ¹⁰ represent an aryl group which may have a substituent. Examples of the aryl group include a phenyl group and a naphthyl group. However, when the conjugated system is highly expanded with a substituent such as a condensed polycycle, the interaction between molecules becomes strong, and the solubility in a solvent decreases. An aryl group having 3 or less rings is preferable, an aryl group having 2 or less rings is more preferable, and a phenyl group is particularly preferable. As the substituent, a lower alkyl group having 3 or less carbon atoms such as a methyl group, an ethyl group, and a 2-propyl group is preferable. These substituents may be bonded to each other to have an alicyclic structure such as a cyclopentane ring or a cyclohexane ring, or the substituents may be bonded to each other within Ar ⁹ or Ar ¹⁰ to form a cyclopentyl ring or a cyclohexyl ring. A ring structure such as the above may be formed. Among these, Ar ⁹ and Ar ¹⁰ are more preferably 4-methylphenyl groups from the viewpoint of mobility as a charge transport material.

Ar ¹¹ and Ar ¹² represent an aryl group which may have a substituent. As the aryl group, a phenyl group, a naphthyl group, and the like can be mentioned. However, when the conjugated system is highly expanded, solubility in a solvent is reduced, and therefore an aryl group having 3 or less rings is preferable, and more preferably, An aryl group having 2 or less rings, particularly preferably a phenyl group. Examples of the substituent that may have include a lower alkyl group having 3 or less carbon atoms such as a methyl group, an ethyl group, and a 2-propyl group. When Ar ¹¹ and Ar ¹² are bonded to each other or bonded to each other through an alkylene group or the like to form a ring structure, the planarity of the molecule itself is increased, and the interaction between the molecules is increased. Ar ¹¹ and Ar ¹² do not bond to each other or form a ring structure via an alkylene group or the like because the solubility of the hydrazone compound decreases and the possibility of precipitation after coating of the photosensitive layer increases. Of the aryl group having a substituent and the unsubstituted aryl group, an unsubstituted phenyl group is more preferable in view of the versatility of the reagent and the performance when used as an electrophotographic photoreceptor.

Ar ¹³ represents an arylene group which may have a substituent. Examples of the arylene group include a phenylene group, a naphthylene group, and an anthranylene group. Examples of the substituent that may be included include a lower alkyl group having 3 or less carbon atoms such as a methyl group, an ethyl group, and a 2-propyl group, and these substituents are bonded to each other to form a cyclopentane ring, a cyclohexane. It may have an alicyclic structure such as a ring. As described above, when Ar ¹³ has a condensed polycyclic structure, the solubility in an organic solvent used as a coating solvent is reduced, and therefore, a phenylene group is preferable, and mobility as a charge transport material is low. From the viewpoint, an unsubstituted phenylene group is more preferable.

  The suitable structure of the hydrazone compound which can be used for this invention below is illustrated. The following exemplary compounds a to r are used for clarifying the gist of the present invention, and are not limited to the exemplified structures unless they are contrary to the gist of the present invention.

  As described above, in the present invention, a hydrazone compound is used as the charge transport material, but the hydrazone compound may be used alone or in combination with other charge transport materials. The charge transporting material used in combination is not particularly limited as long as it is a known material. For example, aromatic nitro compounds such as 2,4,7-trinitrofluorenone, and cyano compounds such as tetracyanoquinodimethane , Electron withdrawing materials such as quinone compounds such as diphenoquinone, carbazole derivatives, indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, thiadiazole derivatives, heterocyclic compounds such as benzofuran derivatives, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, Examples thereof include electron donating materials such as stilbene derivatives, butadiene derivatives, enamine derivatives and those obtained by bonding a plurality of these compounds, or polymers having a group consisting of these compounds in the main chain or side chain. Among these, carbazole derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives, and those in which a plurality of these compounds are bonded are preferable.

(Conductive support)
As the conductive support, for example, a metal material such as aluminum, aluminum alloy, stainless steel, copper, nickel, or a resin material imparted with conductivity by adding conductive powder such as metal, carbon, tin oxide, Mainly used are resin, glass, paper, or the like obtained by depositing or coating a conductive material such as aluminum, nickel, ITO (indium-tin oxide) on its surface. As a form, a drum shape, a sheet shape, a belt shape or the like is used. A conductive material having an appropriate resistance value may be coated on a conductive support made of a metal material in order to control conductivity and surface properties and to cover defects.

  When a metal material such as an aluminum alloy is used as the conductive support, it may be used after anodizing, chemical conversion coating or the like. When anodizing is performed, it is desirable to perform sealing by a known method.

  The surface of the conductive support may be smooth or roughened by applying a special cutting method or polishing method. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the conductive support.

(Underlayer)
An undercoat layer may be provided between the conductive support and the photosensitive layer in order to improve adhesion and blocking properties.

  As the undercoat layer, a resin or a resin in which particles such as a metal oxide are dispersed is used. Examples of the metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium titanate and barium titanate. As described above, as the metal oxide particles, only one type of particle may be used, or a plurality of types of particles may be mixed and used. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicone. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. A thing of a several crystalline state may be contained.

  In addition, various particle diameters of the metal oxide particles can be used. Among these, from the viewpoint of characteristics and liquid stability, the average primary particle diameter is preferably 10 nm to 100 nm, particularly preferably 10 nm to 50 nm. It is as follows.

  The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. As binder resin used for the undercoat layer, phenoxy, epoxy, polyvinylpyrrolidone, polyvinyl alcohol, casein, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, etc. are used alone or in a cured form together with a curing agent. Among them, alcohol-soluble copolymer polyamides, modified polyamides, and the like are preferable because they exhibit good dispersibility and coatability.

  The addition ratio of the inorganic particles to the binder resin can be arbitrarily selected, but it is preferably used in the range of 10% by weight or more and 500% by weight or less from the viewpoint of the stability of the dispersion and the coating property.

  The thickness of the undercoat layer can be arbitrarily selected, but is preferably 0.1 μm or more and 25 μm or less in view of the photoreceptor characteristics and applicability. Further, a known antioxidant or the like may be added to the undercoat layer.

(Photosensitive layer)
Next, the photosensitive layer formed on the conductive support (on the undercoat layer when the above-described undercoat layer is provided) will be described. The photosensitive layer is a layer containing the polyester resin containing the repeating structure represented by the general formula (1) or (2) described above and the hydrazone compound described above. The type of the photosensitive layer includes a charge generation material and charge transport. A single layer type consisting of the same layer in which a material (including a hydrazone compound) is dispersed or dissolved in a polyester resin as a binder resin, a charge generation layer in which a charge generation material is dispersed or dissolved in a binder resin, and a charge transport material ( A laminate type composed of two layers of a charge transport layer in which a hydrazone compound is dispersed or dissolved in a polyester resin as a binder resin may be mentioned, and any form thereof may be used. In general, it is known that the charge transport material exhibits the same performance as a charge transfer function regardless of whether it is a single layer type or a laminated type.

  In addition, as the laminated photosensitive layer, a forward laminated photosensitive layer in which a charge generation layer and a charge transport layer are laminated in this order from the conductive support side, and conversely, a reverse lamination type in which a charge transport layer and a charge generation layer are laminated in this order. There is a photosensitive layer, and any of them can be adopted, but a sequentially laminated photosensitive layer capable of exhibiting the most balanced photoconductivity is preferable. In the following description, a multilayer photoconductor will be described as an example unless otherwise specified.

(Charge generation layer)
When the photosensitive layer is a laminated type, examples of the charge generation material used for the charge generation layer include selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials, or phthalocyanine pigments, azo pigments, quinacridone pigments, Various photoconductive materials such as indigo pigments, perylene pigments, polycyclic quinone pigments, organic pigments such as anthanthrone pigments and benzimidazole pigments can be used. Of these, organic pigments are preferable, and phthalocyanine pigments and azo pigments are particularly preferable. These charge generating materials include, for example, polyester resins, polyvinyl acetate, polyacrylic acid esters, polymethacrylic acid esters, polyesters, polycarbonates, polyvinyl acetoacetals, polyvinyl propionals, polyvinyl butyrals, phenoxy resins, epoxy resins, urethane resins, and cellulose esters. It is used in a form bound with various binder resins such as cellulose ether. In this case, the charge generation material is used in the range of 30 to 500 parts by weight of the charge generation material with respect to 100 parts by weight of the binder resin, and the film thickness is usually 0.1 to 1 μm, preferably The thickness is preferably 0.15 μm or more and 0.6 μm or less.

  When using a phthalocyanine compound as the charge generation material, specifically, a metal such as metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, or an oxide or halide thereof. Ordered phthalocyanine compounds are used. Examples of the ligand to a trivalent or higher metal atom include an oxygen atom, a chlorine atom, a hydroxyl group, an alkoxy group, and the like. Particularly preferred are X-type, τ-type metal-free phthalocyanine, titanyl phthalocyanine such as A-type, B-type, and D-type, vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine, and hydroxygallium phthalocyanine. Of the crystal forms of titanyl phthalocyanine mentioned here, A type and B type are described in W.W. It has been shown by Heller et al. As phase I and phase II, respectively (Zeit. Kristallogr. 159 (1982) 173), and type A is known as a stable type. The D-type is a crystal type characterized by a clear peak at a diffraction angle 2θ ± 0.2 ° of 27.3 ° in powder X-ray diffraction using CuKα rays. The phthalocyanine compound may be a single compound or a mixture of several phthalocyanine compounds. When the phthalocyanine compound is used in a mixed state, the respective constituent elements may be mixed and used later, or may be a mixed state in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, and crystallization. good. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known.

(Charge transport layer)
When the photosensitive layer is a laminated type, the hydrazone compound described above is used as a charge transport material used for the charge transport layer. As described above, the hydrazone compound may be used alone or in combination with another charge transporting material, and the charge transporting material has a repeating structure represented by the general formula (1) or (2). The charge transport layer is formed in a form bound to a binder resin containing a polyester resin. The charge transport layer may be composed of a single layer, or may be a stack of a plurality of layers having different constituent components or composition ratios.

  The ratio of the binder resin to the charge transport material is usually 30 to 200 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. When the hydrazone compound is used in combination with another charge transport material, the ratio of the hydrazone compound to the other charge transport material is arbitrary, but the hydrazone compound is usually 50% by weight or more, preferably 90% by weight or more. is there. In particular, it is preferable to use only a hydrazone compound as the charge transport material. The film thickness is generally 5 to 50 μm, preferably 10 to 45 μm.

  The charge transport layer has well-known plasticizers, antioxidants, ultraviolet absorbers, electrons, and the like in order to improve film forming properties, flexibility, coating properties, stain resistance, gas resistance, light resistance, etc. You may contain additives, such as an attractive compound, dye, a pigment, and a leveling agent. Examples of the antioxidant include hindered phenol compounds and hindered amine compounds. Examples of dyes and pigments include various pigment compounds and azo compounds.

  Next, the dispersion type (single layer type) photosensitive layer will be described. When the photosensitive layer is a dispersion type, the above-described charge generating material is dispersed in the charge transport medium having the above-described mixing ratio. In this case, the particle size of the charge generation material needs to be sufficiently small, and is preferably 1 μm or less, more preferably 0.5 μm or less. If the amount of the charge generating material dispersed in the photosensitive layer is too small, sufficient sensitivity cannot be obtained, and if it is too large, there are adverse effects such as a decrease in chargeability and a decrease in sensitivity, for example, preferably 0.5 to 50 weight. %, More preferably 1 to 20% by weight.

  The film thickness of the dispersion type photosensitive layer is usually 5 to 50 μm, more preferably 10 to 45 μm. Also in this case, known plasticizers for improving film formability, flexibility, mechanical strength, additives for suppressing residual potential, dispersion aids for improving dispersion stability, coating Leveling agents for improving the properties, surfactants such as silicone oil, fluorine oil and other additives may be added.

  In addition, on the dispersion type photosensitive layer or the laminated type photosensitive layer, for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to a discharge product generated from a charger or the like. A protective layer may be provided. Further, for the purpose of reducing frictional resistance and wear on the surface of the photoreceptor, the surface layer may contain a fluorine-based resin, a silicone resin, or the like. Moreover, the particle | grains which consist of these resin, and the particle | grains of an inorganic compound may be included.

(Method for forming each layer)
Each of the layers constituting the electrophotographic photosensitive member is obtained by immersing, coating, spraying, nozzle coating, bar coating, roll coating, a coating solution obtained by dissolving or dispersing a material to be contained in a solvent. It is formed by sequentially coating by a known method such as blade coating. Among these, the dip coating method is preferable because of its high productivity.

  There is no particular limitation on the solvent used for preparing the coating solution, that is, the solvent or the dispersion medium. Specific examples include alcohols such as methanol, ethanol, propanol, and 2-methoxyethanol, tetrahydrofuran, 1,4-dioxane, Ethers such as dimethoxyethane, esters such as methyl formate and ethyl acetate, ketones such as acetone, methyl ethyl ketone, cyclohexanone and 4-methoxy-4-methyl-2-pentanone, and aromatic hydrocarbons such as benzene, toluene and xylene , Chlorinated hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2 trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichloroethylene, n-butylamine, Isopropanol amino , Diethylamine, triethanolamine, ethylenediamine, nitrogen-containing compounds such as triethylenediamine, acetonitrile, N- methylpyrrolidone, N, N- dimethylformamide, aprotic polar solvents such as dimethyl sulfoxide and the like. Moreover, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and kinds.

  In addition, the amount of solvent used is not particularly limited, but considering the purpose of each layer and the properties of the selected solvent, it may be appropriately adjusted so that the physical properties such as the solid content concentration and viscosity of the coating solution are within a desired range. preferable.

  The above-mentioned polyester resin, which is a binder resin used in the present invention, is preferable because it has excellent solubility in the solvent used in the coating step and also has excellent stability of the coating solution after dissolution.

[Image forming apparatus]
Next, an embodiment of an image forming apparatus using the electrophotographic photosensitive member of the present invention (an image forming apparatus of the present invention) will be described with reference to FIG. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.

  As shown in FIG. 1, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device (charging unit) 2, an exposure device (exposure unit) 3, and a developing device (developing unit) 4. Accordingly, a transfer device 5, a cleaning device 6, and a fixing device 7 are provided.

  The electrophotographic photoreceptor 1 is not particularly limited as long as it is the above-described electrophotographic photoreceptor of the present invention, but in FIG. 1, as an example, a drum in which the above-described photosensitive layer is formed on the surface of a cylindrical conductive support. The electrophotographic photosensitive member is shown. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged along the outer peripheral surface of the electrophotographic photoreceptor 1.

  The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2, but other corona charging devices such as corotron and scorotron, contact-type charging devices such as charging brushes and charging films, etc. are often used. Used.

  In many cases, the electrophotographic photosensitive member 1 and the charging device 2 are cartridges having both of them (the electrophotographic photosensitive member cartridge of the present invention. Designed to be removable from. However, the charging device 2 may be provided separately from the cartridge, for example, in the main body of the image forming apparatus. For example, when the electrophotographic photoreceptor 1 or the charging device 2 is deteriorated, the photoreceptor cartridge can be detached from the image forming apparatus main body, and another new photoreceptor cartridge can be mounted on the image forming apparatus main body. It has become. Also, the toner described later is often stored in the toner cartridge and designed to be removable from the main body of the image forming apparatus. When the toner in the used toner cartridge runs out, this toner cartridge is removed. It can be removed from the main body of the image forming apparatus and another new toner cartridge can be mounted. Further, a cartridge equipped with all of the electrophotographic photosensitive member 1, the charging device 2, and the toner may be used.

  The type of the exposure apparatus 3 is not particularly limited as long as it can expose the electrophotographic photoreceptor 1 to form an electrostatic latent image on the photosensitive surface of the electrophotographic photoreceptor 1. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, LEDs, and the like. Further, exposure may be performed by a photoreceptor internal exposure method. The light used for the exposure is arbitrary, but monochromatic light is generally preferable. For example, monochromatic light having a wavelength of 780 nm, monochromatic light having a wavelength of 600 nm to 700 nm, slightly short wavelength, and monochromatic light having a wavelength of 380 nm to 500 nm. For example, exposure may be performed.

  The type of the developing device 4 is not particularly limited as long as it can develop the exposed electrostatic latent image on the electrophotographic photosensitive member 1 into a visible image. Specific examples include dry development methods such as cascade development, one-component conductive toner development, and two-component magnetic brush development, and wet development methods. In FIG. 1, the developing device 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and has a configuration in which toner T is stored inside the developing tank 41. . Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing device 4 as necessary. This replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge.

  The supply roller 43 is formed from a conductive sponge or the like. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicone resin, a urethane resin, a fluororesin, or the like. The surface of the developing roller 44 may be smoothed or roughened as necessary.

  The developing roller 44 is disposed between the electrophotographic photoreceptor 1 and the supply roller 43 and is in contact with the electrophotographic photoreceptor 1 and the supply roller 43, respectively. However, the developing roller 44 and the electrophotographic photosensitive member 1 may not be in contact with each other but may be close to each other. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism (not shown). The supply roller 43 carries the stored toner T and supplies it to the developing roller 44. The developing roller 44 carries the toner T supplied by the supply roller 43 and contacts the surface of the electrophotographic photosensitive member 1.

  The regulating member 45 is formed of a resin blade such as a silicone resin or a urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such a metal blade with a resin. This regulating member 45 normally abuts on the developing roller 44 and is pressed against the developing roller 44 side with a predetermined force by a spring or the like (a general blade linear pressure is 5 to 500 g weight / cm). If necessary, the regulating member 45 may be provided with a function of imparting charging to the toner T by frictional charging with the toner T.

  The agitator 42 is provided as necessary, and is rotated by a rotation driving mechanism, and agitates the toner T and conveys the toner T to the supply roller 43 side. A plurality of agitators 42 may be provided with different blade shapes and sizes.

  The type of the toner T is arbitrary, and besides the pulverized toner, a polymerized toner using a suspension polymerization method, an emulsion polymerization method, or the like can be used. In particular, when a polymerized toner is used, a toner having a small particle diameter of about 4 μm to 8 μm is preferable, and the toner particles are used in a variety of shapes from a nearly spherical shape to a shape outside the potato-like spherical shape. be able to. The polymerized toner is excellent in charging uniformity and transferability and is suitably used for high image quality.

  The type of the transfer device 5 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. . Here, it is assumed that the transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like disposed so as to face the electrophotographic photoreceptor 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner T, and transfers the toner image formed on the electrophotographic photosensitive member 1 to a recording paper (paper, medium) P. Is.

  There is no restriction | limiting in particular about the cleaning apparatus 6, Arbitrary cleaning apparatuses, such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, can be used. The cleaning device 6 scrapes the residual toner adhering to the electrophotographic photosensitive member 1 with a cleaning member and collects the residual toner. If there is little or almost no residual toner, the cleaning device 6 may be omitted.

  The fixing device 7 includes an upper fixing member (pressure roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 1 shows an example in which a heating device 73 is provided inside the upper fixing member 71. The upper and lower fixing members 71 and 72 include a fixing roll in which a metal base tube made of stainless steel, aluminum, or the like is coated with silicon rubber, a fixing roll in which Teflon (registered trademark) resin is coated, a fixing sheet, or the like. A member can be used. Further, each of the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

  When the toner transferred onto the recording paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P.

  The type of the fixing device is not particularly limited, and a fixing device of an arbitrary method such as heat roller fixing, flash fixing, oven fixing, pressure fixing, or the like can be provided.

  In the image forming apparatus configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the electrophotographic photosensitive member 1 is charged to a predetermined potential (for example, −600 V) by the charging device 2. At this time, charging may be performed with a DC voltage, or charging may be performed by superimposing an AC voltage on the DC voltage.

  Subsequently, the photosensitive surface of the charged electrophotographic photosensitive member 1 is exposed by the exposure device 3 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. Then, development of the electrostatic latent image formed on the photosensitive surface of the electrophotographic photoreceptor 1 is performed by the developing device 4.

  The developing device 4 thins the toner T supplied by the supply roller 43 with a regulating member (developing blade) 45 and has a predetermined polarity (here, the same polarity as the charging potential of the electrophotographic photosensitive member 1). Negatively charged) and conveyed while being carried on the developing roller 44 and brought into contact with the surface of the electrophotographic photosensitive member 1.

  When the charged toner T carried on the developing roller 44 contacts the surface of the electrophotographic photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the electrophotographic photoreceptor 1. This toner image is transferred onto the recording paper P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the electrophotographic photosensitive member 1 without being transferred is removed by the cleaning device 6.

  After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing device 7 and thermally fixing the toner image onto the recording paper P.

  In addition to the above-described configuration, the image forming apparatus may be configured to perform, for example, a static elimination process. The neutralization step is a step of neutralizing the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member, and a fluorescent lamp, an LED, or the like is used as the neutralizing device. In addition, the light used in the static elimination process is often light having an exposure energy that is at least three times that of the exposure light.

  The image forming apparatus may be further modified. For example, the image forming apparatus may be configured to perform a pre-exposure process, an auxiliary charging process, or the like, or may be configured to perform offset printing. A full-color tandem system configuration using toner may be used.

  In this embodiment, the electrophotographic photosensitive member cartridge of the present invention has been described by exemplifying the photosensitive member cartridge including the electrophotographic photosensitive member 1 and the charging device 2. However, the electrophotographic photosensitive member cartridge of the present invention is electrophotographic. The photosensitive member 1 may be provided with at least one of a charging device (charging unit) 2, an exposure device (exposure unit) 3, and a developing device (developing unit) 4. Specifically, for example, the electrophotographic photosensitive member cartridge of the present invention includes all of the electrophotographic photosensitive member 1, the charging device (charging unit) 2, the exposure device (exposure unit) 3, and the developing device (developing unit) 4. You may comprise as a cartridge.

  Hereinafter, the present embodiment will be described more specifically based on examples. In addition, the following examples are shown in order to describe the present invention in detail, and the present invention is not limited to the examples shown below unless it is contrary to the gist thereof. Moreover, the description of “parts” in the following examples, comparative examples and reference examples indicates “parts by weight” unless otherwise specified.

[Production of resin]
First, measurement of the viscosity average molecular weight will be described. A polyester resin is dissolved in dichloromethane to prepare a solution having a concentration C of 6.00 g / L. The flow time t of the sample solution is measured in a constant temperature water bath set to 20.0 ° C. using an Ubbelohde capillary viscometer with a flow time t ₀ of the solvent (dichloromethane) of 136.16 seconds. The viscosity average molecular weight Mv is calculated according to the following formula.

a = 0.438 × η _sp +1 η _sp = t / t ₀ −1
b = 100 × η _sp / C C = 6.00 (g / L)
η = b / a
Mv = 3207 × η ^1.205

  Next, the manufacturing method of a polyester resin is demonstrated.

(Production Example 1: Polyester resin X)
In a 1000 mL beaker, 23.01 g of sodium hydroxide and 940 mL of H ₂ O were weighed and dissolved while stirring. Thereto, 49.36 g of bis (4-hydroxy-3-methylphenyl) methane (hereinafter referred to as “BP-a”) was added, stirred and dissolved, and then the aqueous alkaline solution was transferred to a 2 L reaction vessel. Next, 0.5766 g of benzyltriethylammonium chloride and 1.2955 g of 2,3,5-trimethylphenol were sequentially added to the reaction vessel. Next, a mixed solution of 65.27 g of diphenyl ether-4,4′-dicarboxylic acid chloride and 470 mL of dichloromethane was transferred into the dropping funnel. While maintaining the external temperature of the polymerization tank at 20 ° C. and stirring the alkaline aqueous solution in the reaction tank, the dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 5 hours, 783 mL of dichloromethane was added and stirring was continued for 7 hours. Thereafter, 8.34 mL of acetic acid was added and stirred for 30 minutes, and then the stirring was stopped and the organic layer was separated. This organic layer was washed twice with 942 mL of a 0.1N aqueous sodium hydroxide solution, then washed twice with 942 mL of 0.1N hydrochloric acid, and further washed twice with 942 mL of H ₂ O. The organic layer after washing was poured into 6266 mL of methanol, and the resulting precipitate was taken out by filtration and dried to obtain the desired polyester resin X. The obtained polyester resin X had a viscosity average molecular weight of 51,400. The repeating structure of the polyester resin X is shown below.

(Production Example 2: Polyester resin Y)
In a 1000 mL beaker, 22.34 g of sodium hydroxide and 940 mL of H ₂ O were weighed and dissolved with stirring. Thereto was added 51.04 g of 1,1-bis (4-hydroxy-3-methylphenyl) ethane (hereinafter referred to as “BP-b”), stirred and dissolved, and the aqueous alkaline solution was added to a 2 L reactor. Moved. Next, 0.5579 g of benzyltriethylammonium chloride and 1.0613 g of 2,3,5-trimethylphenol were sequentially added to the reaction vessel. Separately, a mixed solution of 63.37 g of diphenyl ether-4,4′-dicarboxylic acid chloride and 470 mL of dichloromethane was transferred into the dropping funnel. While maintaining the external temperature of the polymerization tank at 20 ° C. and stirring the alkaline aqueous solution in the reaction tank, the dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 5 hours, 783 mL of dichloromethane was added and stirring was continued for 7 hours. Thereafter, 8.10 mL of acetic acid was added and stirred for 30 minutes, then stirring was stopped and the organic layer was separated. This organic layer was washed twice with 942 mL of 0.1N aqueous sodium hydroxide solution, then twice with 942 mL of 0.1N hydrochloric acid, and further washed twice with 942 mL of H ₂ O. The organic layer after washing was poured into 6266 mL of methanol, and the resulting precipitate was removed by filtration and dried to obtain the desired polyester resin Y. The viscosity average molecular weight of the obtained polyester resin Y was 51,700. The repeating structure of the polyester resin Y is shown below.

(Production Example 3: Polyester resin Z)
In a 500 mL beaker, 7.20 g of sodium hydroxide and 282 mL of H ₂ O were weighed and dissolved with stirring. Then, 17.40 g of 2,2-bis (4-hydroxy-3-methylphenyl) propane (hereinafter referred to as “BP-c”) was added, stirred and dissolved, and the aqueous alkaline solution was added to a 1 L reactor. Moved. Next, 0.1798 g of benzyltriethylammonium chloride and 0.3421 g of 2,3,5-trimethylphenol were sequentially added to the reaction vessel. Separately, a mixed solution of 10.21 g of diphenyl ether-4,4′-dicarboxylic acid chloride, 4.22 g of terephthalic acid chloride, 2.81 g of isophthalic acid chloride, and 141 mL of dichloromethane was transferred into the dropping funnel. While maintaining the external temperature of the polymerization tank at 20 ° C. and stirring the alkaline aqueous solution in the reaction tank, the dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 4 hours, 235 mL of dichloromethane was added and stirring was continued for 8 hours. Thereafter, 2.61 mL of acetic acid was added and stirred for 30 minutes, and then stirring was stopped and the organic layer was separated. This organic layer was washed twice with 283 mL of a 0.1N aqueous sodium hydroxide solution, then washed twice with 283 mL of 0.1N hydrochloric acid, and further washed twice with 283 mL of H ₂ O. The organic layer after washing was poured into 1880 mL of methanol, and the resulting precipitate was removed by filtration and dried to obtain the desired polyester resin Z. The resulting polyester resin Z had a viscosity average molecular weight of 47,100. The repeating structure of the polyester resin Z is shown below.

[Manufacture of photoreceptor sheet]
Example 1
A dispersion for the undercoat layer was produced as follows. That is, a rutile type titanium oxide having an average primary particle size of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by weight of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide were flowed at high speed. In a mixed solvent of methanol / 1-propanol in a mixed solvent of methanol / 1-propanol, which was introduced into a mixing kneader (“SMG300” manufactured by Kawata Co., Ltd.) and mixed at a high rotational speed of 34.5 m / sec. Then, a dispersion slurry of hydrophobized titanium oxide was obtained by dispersing with a ball mill. The dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam [compound represented by the following formula (A)] / bis (4-amino-3-methylcyclohexyl) methane [the following formula (B Compound represented by the following formula (C)] / decamethylene dicarboxylic acid [compound represented by the following formula (D)] / octadecamethylene dicarboxylic acid [in the following formula (E) The compositional molar ratio of the compound represented] is 60% / 15% / 5% / 15% / 5% of the copolymerized polyamide pellets with heating and stirring and mixing to dissolve the polyamide pellets. By performing sonic dispersion treatment, the weight ratio of methanol / 1-propanol / toluene is 7/1/2, and the hydrophobically treated titanium oxide / co-polymer is mixed. Containing a slip polyamide in a weight ratio of 3/1, and a solid concentration of 18.0% of the undercoat layer dispersion.

  The undercoat layer-forming coating solution thus obtained was applied onto a polyethylene terephthalate sheet having aluminum deposited on the surface with a wire bar so that the film thickness after drying was 1.2 μm, and dried. Was provided.

  Next, 10 parts by weight of oxytitanium phthalocyanine having the powder X-ray diffraction spectrum shown in FIG. In addition to 150 parts by weight of 2-dimethoxyethane, pulverization and dispersion treatment was performed with a sand grind mill to prepare a pigment dispersion. 160 parts by weight of the pigment dispersion thus obtained, 100 parts by weight of a 5% 1,2-dimethoxyethane solution of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name # 6000C), and an appropriate amount of 1,2-dimethoxy Ethane was mixed to finally produce a dispersion having a solid concentration of 4.0%.

  The dispersion was applied on the undercoat layer with a wire bar so that the film thickness after drying was 0.4 μm, and then dried to form a charge generation layer.

  Next, 50 parts by weight of the charge transport material of hydrazone compound (3-1) shown below, 100 parts by weight of the polyester resin X produced in Production Example 1, 0.05 parts by weight of silicone oil as a leveling agent, and a mixed solvent of tetrahydrofuran and toluene Mixing with 640 parts by weight of tetrahydrofuran (80% by weight, toluene 20% by weight), a coating solution for forming a charge transport layer was prepared. This solution is applied on the above-described charge generation layer using an applicator so that the film thickness after drying is 25 μm, and dried at 125 ° C. for 20 minutes to form a charge transport layer, whereby the photosensitive sheet A is obtained. Produced. At this time, the solubility of the polyester resin X in the solvent was good.

(Example 2)
A photoreceptor sheet B was produced in the same manner as in Example 1 except that the polyester resin X used in the coating liquid for forming a charge transport layer in Example 1 was changed to the polyester resin Y produced in Production Example 2. At this time, the solubility of the polyester resin Y in the solvent was good.

(Example 3)
A photoreceptor sheet C was produced in the same manner as in Example 1 except that the polyester resin X used in the coating liquid for forming a charge transport layer in Example 1 was changed to the polyester resin Z produced in Production Example 3. At this time, the solubility of the polyester resin Z in the solvent was good.

(Comparative Example 1)
A photoreceptor sheet D was produced in the same manner as in Example 1 except that the polyester resin X used in the charge transport layer forming coating solution of Example 1 was changed to the polyester resin W having the following structure. The polyester resin W can be produced by a known method. The viscosity average molecular weight of the polyester resin W was 52,000.

(Comparative Example 2)
Instead of 50 parts of the charge transport material (3-1) used in the charge transport layer forming coating solution of Example 3, 45 parts of the charge transport material (4-1) and charge transport material (4-2) 5 having the following structure A photoconductor sheet E was produced in the same manner as in Example 2 except that 50 parts of the charge transport material was used.

(Comparative Example 3)
Example 2 except that 50 parts of the charge transport material (5-1) having the following structure was used in place of 50 parts of the charge transport material (3-1) used in the coating liquid for forming the charge transport layer of Example 2. Similarly, a photoreceptor sheet F was produced.

(Reference Example 1)
A photoreceptor sheet G was prepared in the same manner as in Example 2 except that the polycarbonate resin V formed of the following repeating structural units was used instead of the polyester resin Y used in the charge transport layer forming coating solution of Example 2. did. The viscosity average molecular weight of the polycarbonate resin V is 50,500.

(Reference Example 2)
A photosensitive sheet H was prepared in the same manner as in Comparative Example 2 except that the polycarbonate resin V formed of the above-mentioned repeating structural units was used instead of the polyester resin Y used in the coating liquid for forming the charge transport layer of Comparative Example 2. Produced.

(Reference Example 3)
A photoreceptor sheet I was prepared in the same manner as in Comparative Example 3 except that the polycarbonate resin V formed of the above-described repeating structural units was used instead of the polyester resin Y used in the charge transport layer forming coating solution of Comparative Example 3. Produced.

[Characteristic evaluation]
The manufactured photoreceptor sheets A, B, C, D, E, F, G, H, and I were subjected to the following electrical property test and wear test. These results are summarized in Table 1.

(Electrical characteristics test)
An electrophotographic characteristic evaluation apparatus manufactured according to the electrophotographic society measurement standard (basic and applied electrophotographic technology, edited by the Electrophotographic Society, Corona, pages 404 to 405) is used, and the photoreceptor sheet has an outer diameter of 80 mm. After the aluminum drum and the aluminum substrate of the photosensitive sheet are connected to each other, the drum is rotated at a constant rotational speed of 60 rpm to charge, expose, measure potential, and remove static electricity. An electrical property evaluation test by cycle was performed. At that time, the photosensitive member was charged so that the initial surface potential was − (minus, the same applies hereinafter) to 700 V, and the light from the halogen lamp was converted to monochromatic light of 780 nm with an interference filter and exposed at 1.0 μJ / cm ² . The post-exposure surface potential after 100 milliseconds (hereinafter sometimes referred to as VL) was measured. In the VL measurement, the time required from the exposure to the potential measurement was set to 100 ms, which was a fast response condition. The measurement environment was a temperature of 25 ° C. and a relative humidity of 50% (hereinafter sometimes referred to as NN environment) and a temperature of 5 ° C. and a relative humidity of 10% (hereinafter sometimes referred to as LL environment). The obtained results are shown in Table 1.

(Abrasion test)
The photoreceptor sheet was cut into a circle having a diameter of 10 cm, and the wear was evaluated with a Taber abrasion tester (manufactured by Taber). Test conditions were measured by comparing the weight before and after the test with 1000 wheels without load (the weight of the wear wheel) under the atmosphere of 23 ° C. and 50% RH and without wear (self-weight of the wear wheel). did. The results are shown in Table 1.

  In Table 1, BP-a represents bis (4-hydroxy-3-methylphenyl) methane (see Production Example 1), and BP-b represents 1,1-bis (4-hydroxy-3-methyl). Phenyl) ethane (see Production Example 2) and BP-c represents 2,2-bis (4-hydroxy-3-methylphenyl) propane (see Production Example 3). ODBA is diphenyl ether-4,4′-dicarboxylic acid represented by the following chemical formula (i), TPA is terephthalic acid represented by the following chemical formula (ii), and IPA is isophthalic acid represented by the following chemical formula (iii). . CTM is a charge transport material.

  The photoreceptors E and H using the charge transport material (4-1) / (4-2) were not sufficiently charged in the LL environment, and their characteristics could not be evaluated.

  From this result, the present invention containing a polyester resin containing a diphenyl ether-dicarboxylic acid residue, such as the photoreceptors A, B, and C of Examples 1, 2, and 3 and the photoreceptors E and F of Comparative Examples 2 and 3, respectively. As shown in the results of the Taber test, it can be seen that the photoconductor is excellent in wear resistance. Among them, the photoreceptors A, B, and F containing the polyester resin represented by the general formula (2) show particularly good values.

  By the way, as shown by the results of the electrical characteristics of the photoconductors G, H, and I of Reference Examples 1, 2, and 3, the photoconductor using a polycarbonate resin known as a photoconductor for the binder is used in the present invention. The hydrazone compound (3-1) has no significant advantage over the charge transport materials (4-1) / (4-2) and (5-1) which are outside the scope of the present invention.

  On the other hand, in the photoreceptor using the polyester resin Y of the present invention as a binder, the VL in the NN environment of the photoreceptor B of Example 2 using the hydrazone compound (3-1) of the present invention is -60V. The VL in the NN environment of the photoreceptor F of Comparative Example 3 using the charge transport material (5-1) outside the scope of the present invention is −83 V, and is preferable only when the hydrazone compound of the present invention is used. It can be seen that

  Similarly, when the polyester resin Z of the present invention is used as a binder, the VL in the NN environment of the photoreceptor B of Example 3 using the hydrazone compound (3-1) is -70 V, whereas The VL in the NN environment of the photoconductor E of Comparative Example 2 using the charge transport material (4-1) / (4-2) outside the range is -87 V, which is preferable only when a hydrazone compound is used. It can be seen that the characteristics are shown.

  Even when a hydrazone compound is used as a charge transport material, when a polyester resin W, which is a known polyester resin, is used as in the photoreceptor D of Comparative Example 1, the electrical characteristics (particularly the LL environment). It can be seen that sufficient characteristics cannot be expressed due to the wear resistance.

[Stability of coating solution]
Next, in order to investigate the stability of the coating solution, the charge transport layer forming coating solution used in Example 2, the charge transport layer forming coating solution used in Comparative Example 3, and the charge transport used in Reference Example 3 were used. The layer forming coating solution was stored at room temperature for 1 month.

Example 4
A photoreceptor sheet J was prepared in exactly the same manner as in Example 2, except that the coating liquid for forming a charge transport layer, which was stored at room temperature for one month in Example 2, was used.

(Comparative Example 4)
A photoreceptor sheet K was produced in exactly the same manner as in Comparative Example 3 except that the charge transport layer forming coating solution stored at room temperature for one month in Comparative Example 3 was used.

(Reference Example 5)
A photoreceptor sheet L was produced in exactly the same manner as in Reference Example 3 except that the coating liquid for forming a charge transport layer that was stored at room temperature for 1 month in Reference Example 3 was used.

  These photoreceptor sheets J, K, and L were subjected to the electrical property test described above. These results are summarized in Table 2.

  From this result, it is found that the coating solution composed of the polyester resin of the present invention and the charge transport material (5-1) other than the present invention undergoes a change over time in one month, and the electrical characteristics are greatly deteriorated. Recognize. On the other hand, the coating solution composed of the polyester resin of the present invention and the hydrazone compound (3-1) of the present invention exhibits electrical properties that are substantially unchanged even after the passage of one month, and has an excellent effect. Recognize. As Reference Example 4, the results of the change over time of the coating liquid composed of polycarbonate and the charge transport material (5-1) are shown, but this is not a big problem. That is, it can be seen from the results that the coating liquid containing the polyester resin of the present invention is highly dependent on the stability of the liquid depending on the charge transport material, and the hydrazone compound is very suitable.

  From the above results, the photoreceptor containing the polyester resin and hydrazone compound of the present invention exhibits high coating solution stability when used as a coating solution for forming a charge transport layer, and has extremely high wear resistance and electrical characteristics. It turns out that it is excellent.

1 is a conceptual diagram illustrating an embodiment of an image forming apparatus using an electrophotographic photosensitive member of the present invention. 1 is an X-ray diffraction pattern of oxytitanium phthalocyanine used in Examples.

Explanation of symbols

1 Photoconductor 2 Charging device (charging roller)
DESCRIPTION OF SYMBOLS 3 Exposure apparatus 4 Developing apparatus 5 Transfer apparatus 6 Cleaning apparatus 7 Fixing apparatus 41 Developing tank 42 Agitator 43 Supply roller 44 Developing roller 45 Control member 71 Upper fixing member (pressure roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper

Claims (5)

In an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support, a polyester resin in which the photosensitive layer includes a repeating structure represented by the following general formula (1), and a hydrazone represented by the following general formula (3) An electrophotographic photoreceptor comprising a compound in the same layer.

(In General Formula (1), Ar ¹ and Ar ² each independently represent a phenylene group which may have a substituent, Ar ³ and Ar ⁴ each represent a phenylene group, and X ¹ has a substituent . Represents an optionally substituted alkylene group.)

(In General Formula (3), Ar ^{9 to} Ar ¹² each independently represent a phenyl group which may have an alkyl group having 3 or less carbon atoms, and Ar ¹³ has an alkyl group having 3 or less carbon atoms. Represents an optional phenylene group.) The electrophotographic photosensitive member according to claim 1, wherein the polyester resin is a polyester resin including a repeating structure represented by the following general formula (2).

(In general formula (2), Ar ⁵ and Ar ⁶ each independently represent a phenylene group which may have a substituent, Ar ⁷ and Ar ⁸ each represent a phenylene group, and R ¹ represents a hydrogen atom or an alkyl group. Represents.)   The photosensitive layer is a laminate of a charge generation layer and a charge transport layer, and the charge transport layer includes a polyester resin including a repeating structure represented by the general formula (1), and the general formula (3). The electrophotographic photosensitive member according to claim 1, comprising a hydrazone compound represented by the formula:   The electrophotographic photosensitive member according to claim 1, a charging unit that charges the electrophotographic photosensitive member, an exposure unit that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image, and An electrophotographic photosensitive member cartridge comprising: at least one developing unit that develops the electrostatic latent image formed on the electrophotographic photosensitive member. An electrophotographic photosensitive member according to any one of claims 1 to 3, a charging member that charges the electrophotographic photosensitive member, and an exposure device that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image; And a developing device for developing the electrostatic latent image formed on the electrophotographic photosensitive member.

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