JP4138692B2 - Electrophotographic photoreceptor - Google Patents

Description

The present invention relates to an environment-friendly electrophotographic photoreceptor containing a PPE resin having a specific structure as a binder resin for a photosensitive layer.
More specifically, by decorating at least one terminal group of a specific PPE resin, electrophotographic performance (especially repetitive characteristics) can be achieved without using a halogen-based solvent such as methylene chloride or an aromatic solvent such as xylene or toluene. Relates to the production of an excellent photoreceptor. Further, the present invention relates to improving the mechanical strength of the photosensitive member by introducing a vinyl group into the terminal group to provide a curing action.

In recent years, electrophotographic technology has been widely used not only in the field of copiers but also in the fields of various printers and facsimiles because of its immediacy, high quality and high storage stability. It is spreading.
Currently, a photoconductive organic compound called OPC (Organic Photo Conductor) is used as an electrophotographic photoreceptor (hereinafter abbreviated as “photoreceptor”) in most copying machines and printers. In particular, the improved performance of OPC materials has led to the recent popularization of copies.
However, conventionally, OPC has been developed with the improvement of functionality first. On the other hand, there has been a lack of consideration for the environment of chemicals (solvents) used in the production of photoreceptors.

In particular, in the production of photoreceptors, it is the mainstream to use these OPC materials dissolved or dispersed in an appropriate solvent.
Conventionally, the main points of developing materials such as charge generation materials and charge transport materials for photoreceptors have been the improvement of the functionality of the photoreceptor and the improvement of the number of printed sheets.
Main characteristics required for these materials include high sensitivity, high chargeability, low photodegradation and thermal degradation, and high charge generation efficiency or charge transport efficiency. Furthermore, in order to improve the printing durability, it is necessary to cope with the improvement in mechanical strength (wear resistance).

For this reason, development of OPC materials (mainly low molecular weight compounds) in this field is thriving, and development of new materials with high transport efficiency and materials with high generation efficiency has been promoted.
On the other hand, as for the binder resin (matrix resin) forming the photosensitive layer of the photoreceptor, as in the case of the charge generation material and the charge transport material, from the viewpoint of placing importance on the functionality and wear resistance of the photoreceptor, the existing so-called Development has been conducted mainly on thermoplastic engineering resins.
In the above development, so-called polyester-based engineering resins such as polycarbonate resins and polyarylate resins have been used as thermoplastic engineering resins. In particular, a polycarbonate resin is often used as a binder resin for a charge transport layer in current photoreceptors in terms of mechanical strength, charge retention, chargeability, and the like of the photoreceptor. These resin bodies are resins that have no problem in safety and hygiene, as well as transparency and weather resistance, which have been used in recent years for transparent materials for substrates such as DVD and CD. However, these polyester-based engineering resins used in conventional photoconductors have poor solubility, and therefore, specific halogen-containing hydrocarbon-based organic solvents (hereinafter referred to as “halogen-based solvents”) that have environmental problems. ) Or ether solvents such as tetrahydrofuran are currently used. Naturally, these polyester-based engineering resins have low molecular weight (1000 to 5000), and chemical treatment from specific structures (introduction of long-chain alkyl groups into side chains) improves solubility to some extent. However, when these corresponding resins are used, problems such as a decrease in mechanical strength, precipitation of charge transport material, non-uniformity, resulting in insufficient charging, and a decrease in sensitivity occur.

Specifically, as an organic solvent in which a charge generating material or a charge transporting material, or a binder resin is dispersed or dissolved as necessary to form a photosensitive layer, methylene chloride (dichloromethane), dichloroethane, trichloroethylene, and monochlorobenzene are used. Halogen solvents such as are used as main solvents. In particular, methylene chloride (dichloromethane) has been often used as a solvent for forming a charge transport layer in a two-layer photoreceptor from the viewpoint of workability efficiency (good evaporation). These solvents are solvents that have a high degree of causing health problems in hygiene, and are not preferred solvents (organic solvent worker text: edited by the Ministry of Health, Labor and Welfare, Occupational Health Division). Furthermore, it has also been designated by the PRTR (Environmental Pollutant Discharge, Transfer Registration) Act as a highly suspected carcinogen.
On the other hand, ether solvents such as tetrahydrofuran tend to cause liver damage, risk of oxidative explosion due to ether bonds, and deterioration of membrane properties due to moisture absorption in the air during drying based on the magnitude of water absorption.

  The present invention provides functions (printing durability, high sensitivity, and high chargeability) equivalent to or higher than those of conventional ones without using a halogen-based solvent or an ether-based solvent as a solvent during the coating formation of the photosensitive layer. It is an object of the present invention to obtain a photoconductor having the same or higher performance as that of a conventional photoconductor corresponding to the environment in terms of manufacturing.

（式（１）中、R１は水素、メチル基であり、R２ は水素、メチル基、カルボキシ基及びそのエステル基である。）を提供することで上記課題を解決した。 The present invention is an electrophotographic photosensitive member in which a photosensitive layer composed of at least an organic photoconductive material and a binder resin is formed on a conductive support, and at least one terminal of the binder resin is represented by the following general formula (1 An electrophotographic photosensitive member characterized by being a PPE (polyphenylene ether) resin having an ether bond with a carbon atom of a methylene group represented by formula (1)

(In the formula (1), R1 is hydrogen and a methyl group, and R2 is hydrogen, a methyl group, a carboxy group, and an ester group thereof) to solve the above problems.

By using a specific PPE resin as the binder resin, it is possible to form a photosensitive layer using an environmentally friendly non-halogen organic solvent instead of a halogen-based solvent. A photoconductor excellent in printability could be obtained by an environmentally friendly manufacturing method.
In addition, when a part of the PPE resin of the present invention was heated, a cross-linking reaction occurred, whereby a photoconductor excellent in wear resistance could be obtained.
For these reasons, the photoreceptor of the present invention can be suitably used as a high-performance photoreceptor for copying machines and printers.

  As a result of diligent research in view of the present situation, the present inventor uses a specific PPE (polyphenylene ether) resin (hereinafter abbreviated as “PPE resin”) as a binder resin used for coating formation of a photosensitive layer. This makes it possible to form a photosensitive layer using environmentally friendly alcohol-based or ketone ester-based organic solvents in place of halogen-based solvents. In addition, it was found that a three-dimensional resin was obtained by annealing, whereby a photoconductor excellent in wear resistance was obtained. The PPE resin body of the present invention is also a novel material as a binder resin for the photoreceptor.

Specifically, a PPE resin having at least one terminal group represented by the following general formula (1) is used as a binder resin.
General formula (1)

（式（１）中、R１は水素、メチル基であり、R２ は水素、メチル基、カルボキシ基及びそのエステル基である。）
PPE樹脂としてはより好ましくは下記一般式（２）として示される。
一般式（２）

(In Formula (1), R1 is hydrogen and a methyl group, R2 is hydrogen, a methyl group, a carboxy group, and its ester group.)
The PPE resin is more preferably represented by the following general formula (2).
General formula (2)

（式２中、X、Yは芳香族の炭素原子を結合手とする２価の残基であり、R１、R２は式（１）と同義である。ｎ、ｍは少なくともいずれか一方が０ではない、０から３００の整数である。）

(In Formula 2, X and Y are divalent residues having an aromatic carbon atom as a bond, and R1 and R2 have the same meanings as in Formula (1). At least one of n and m is 0. Not an integer from 0 to 300.)

  Specifically, R2 in the formula (1) is hydrogen, a methyl group, a carboxy group, and an ester group thereof. Examples of the ester include alkyl esters such as methyl and ethyl, and aryl esters such as phenyl and tolyl. In particular, those having a carboxy group at the end are preferred as the binder resin in the charge generation layer described later. Next, the general formula (2) will be described. X is a 1,4-position, 1,3-position phenylene group, and this includes substituents such as a methyl group, an ethyl group, and a methoxy group. In particular, a 1,4-position phenylene group in which a plurality of methyl groups are substituted tends to be preferable. The biphenylene group means a group in which two benzene rings are directly connected to each other by a single bond, and representative examples thereof include a biphenylene group at the 4th and 4 ′ positions and an alkyl-substituted product thereof. These biphenylene groups are also preferably those having a structure in which a plurality of methyl groups are intentionally substituted.

The bisphenylene group means a bisphenol body which is a raw material of polycarbonate resin and polyarylate resin, and these compounds can be obtained mainly from Honshu Chemical. Specifically, bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) ketone, 2 , 2-bis (4-hydroxyphenyl) propane (bisphenol A), 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4-hydroxyphenyl) phenylmethane, bis (4 -Hydroxyphenyl) diphenyl, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) piperidone, 1,1- Bis (4-hydroxyphenyl) 4,4-dimethylcyclohexane The
In particular, among the resins of the general formula (2), there is a PPE resin having a weight molecular weight of about several thousand to 10,000, in which X is a bisphenylene group (there are two same substituents centering on a carbon atom and an oxygen atom). In view of solubility, electrophotographic characteristics and the like. In terms of the relationship between improved solubility and chemical structure, the general formula (3)

において、Ｒ３とＲ４が互いに結合した構造からなる、１、１― シクロヘキサン、４，４―ジメチル―１、１― シクロヘキサン、1、1― ピペリドン、1、1― シクロペンタン等の６員環及び５員環の単環式の環状体がよい傾向にある。

6 having a structure in which R3 and R4 are bonded to each other, such as 1,1-cyclohexane, 4,4-dimethyl-1,1-cyclohexane, 1,1-piperidone, 1,1-cyclopentane, and the like A monocyclic ring having a member ring tends to be good.

  In relation to the molecular weight, if the molecular weight is low, the film properties deteriorate, and if the molecular weight is large, by-products (residual hydroxyl groups remaining at the end) are likely to be generated, and it is difficult to obtain stable performance. Become. For this reason, 2 to 10 are appropriate for n and m. However, it is inevitable that the production of a single PPE resin will remain a little if the cost of synthesis (purification process) is taken into consideration. This will not have a significant effect on solubility if it remains a little. Furthermore, this does not have much influence on the electrophotographic characteristics. However, when the single PPE resin has a relatively high molecular weight (1000 or more) by weight and the proportion of the single PPE resin exceeds 50%, there is a problem in solubility. Y is preferably a hydrogen or methyl group, an ethyl group substituted or unsubstituted, and particularly an ortho-substituted methyl or dimethyl substituted is preferable for synthesis (it is difficult to produce a by-product).

  Among the resins represented by the general formula (3), X represents a phenylene group for 5-membered and 6-membered rings such as 1,1-cyclohexane, 1,1-cyclopentane, and 1,1-piperidone. PPE resin having a molecular weight of about 1000 to 10,000 is preferable from the viewpoint of solubility, electrophotographic characteristics, raw material surface, and the like.

  Some of these PPE resins of the present invention are described in JP-A Nos. 2003-12796 and 2003-155340. The PPE resin in which X is a 5-membered ring and a 6-membered ring is a novel resin not described in these patents, but can be obtained according to the production method described in the above patent. .

  As a general synthesis method, first, H — (— O—Y) n —O—X—O— (Y—O—) m —H is synthesized, and then this oligomer is represented by the following general formula (4). It can be obtained by adding a methylene chloride solution of the represented acyl halide and using alkylamine such as pyridine and ethylamine, piperidine and the like as a catalyst.

（式（４）中、Ｘはハロゲンである。R_１,R_２は式（１）と同義である。）
次に、代表的な本発明のＰＰＥ樹脂の合成について具体的に説明する。
なお、数平均分子量および重量平均分子量の測定にゲル・パーミエーション・クロマトグラフィー(GPC)法により求めた。 General formula (4)

(In formula (4), X is halogen. R ₁ and R ₂ have the same meanings as in formula (1).)
Next, the synthesis of a typical PPE resin of the present invention will be specifically described.
The number average molecular weight and the weight average molecular weight were determined by gel permeation chromatography (GPC) method.

(Synthesis Example 1)
PPE resin (A)

  CuCl 1.3g (0.013 mol), n, n-dibutylamine 80.0g (0.62 mol), and methyl ethyl ketone 600cc were charged in a 2-liter vertical reactor equipped with a stirrer, thermometer, air inlet tube, and baffle plate. Stirring was performed at a temperature of 40 ° C., and 26.0 g (0.12 mol) of bisphenol A (2,2′-bis (4-hydroxyphenyl) propane) dissolved in 400 cc of methyl ethyl ketone in advance and 76.5 g of 2,6-dimethylphenol ( 0.62 mol) was added dropwise over 2 minutes while bubbling 2 L / min of air, and stirring was continued for 30 minutes after the completion of the dripping while continuing bubbling of 2 L / min of air. Ethylenediaminetetraacetic acid dihydrogen disodium aqueous solution was added thereto to stop the reaction. Then, after washing 3 times with 1M hydrochloric acid aqueous solution, it was washed with ion-exchanged water. The obtained solution was concentrated with an evaporator and further dried under reduced pressure to obtain 753.4 g. This had a number average molecular weight of 1,650, a weight average molecular weight of 2,200, and a hydroxyl group equivalent of 470.

The bifunctional PPE oligomer 25.0 g (hydroxyl group 0.043 mol) and triethylamine 13.1 g (0.129 mol) of the white powder thus obtained were dissolved in 250 cc of methyl ethyl ketone. Next, the reactor equipped with a stirrer, a thermometer and a dropping funnel was cooled to −10 ° C., and 200 ml of a 12.1 g (0.15 mol) acryloyl chloride solution in methylene chloride was added to the reaction solution from the dropping funnel. The solution was added dropwise over 60 minutes so that the temperature was 10 ° C. or lower, and further stirred for 60 minutes after the completion of the addition. Thereafter, this reaction solution was washed three times with a 0.1N aqueous hydrochloric acid solution, washed with ion-exchanged water, and further filtered to remove the generated salt and impurities. Next, methylene chloride and methyl ethyl ketone were distilled off from the resulting solution, washed with methanol, and dried under reduced pressure to obtain 24.2 g of an acrylic body as a white powder.
In the obtained product, the absorption peak (3600 cm ⁻¹ ) of the phenolic hydroxyl group disappeared by IR analysis. Instead, carbonyl absorption occurred at 1780 cm ⁻¹ .

PPE resin (B) & PPE resin (C)

Synthesis of methacryloyl chloride and crotoyl end of oligomer in the same manner as in Synthesis Example 1 using methacryloyl chloride and crotoyl chloride instead of acryloyl chloride and bifunctional PPE oligomer synthesized in Synthesis Example 1 of PPE resin (A) went. A methacrylic end of the PPE resin (B) and a crotoyl were used as the PPE resin (C).
From the IR analysis of both PPE resins thus obtained, the phenolic hydroxyl group absorption peak (3600 cm ⁻¹ ) disappeared. Absorption of carbonyl groups was observed at 1780 and 1760 cm ^-1 respectively.
Furthermore, no halogen atoms were present by the Beilstein test.

(Synthesis Example 2)
PPE resin (D)

  CuCl 1.3g (0.013 mol), n, n-dibutylamine 79.5g (0.62 mol), and methyl ethyl ketone 600cc were charged in a 2-liter vertical reactor equipped with a stirrer, thermometer, air inlet tube, and baffle plate. The mixture was stirred at 40 ° C. and 26.8 g (0.10 mol) of bisphenol Z (1,1′-bis (4-hydroxyphenyl) cyclohexane) and 100.0 g of 2,6-dimethylphenol (0.82) previously dissolved in 500 cc of methyl ethyl ketone. mol) was added dropwise over a period of 120 minutes while bubbling 2 L / min of air, and stirring was continued for 30 minutes after the completion of the drip while continuing bubbling of 2 L / min of air. Ethylenediaminetetraacetic acid dihydrogen disodium aqueous solution was added thereto to stop the reaction. Then, after washing 3 times with 1M hydrochloric acid aqueous solution, it was washed with ion-exchanged water. The obtained solution was concentrated with an evaporator and further dried under reduced pressure to obtain 87.5 g. This had a number average molecular weight of 2960, a weight average molecular weight of 3370, and a hydroxyl group equivalent of 440.

  The bifunctional PPE oligomer 51.0 g (hydroxyl group 0.060 mol) and triethylamine 13.1 g (0.129 mol) of the white powder thus obtained were dissolved in 350 cc of methyl ethyl ketone. Next, the reactor equipped with a stirrer, a thermometer, and a dropping funnel was cooled to −10 ° C., and 200 ml of a methylene chloride solution of acryloyl chloride (0.157 mol) was charged into the solution from the dropping funnel, and the temperature of the reaction solution was changed. The solution was added dropwise over 60 minutes so as to be 10 ° C. or lower, and further stirred for 60 minutes after the completion of the addition. Thereafter, this reaction solution was washed three times with a 0.1N aqueous hydrochloric acid solution, washed with ion-exchanged water, and filtered to remove the generated salt and impurities. Next, methylene chloride and methyl ethyl ketone were distilled off from the resulting solution, washed with methanol, and dried under reduced pressure to obtain 51.6 g of a white powder acrylic body.

In the obtained product, the absorption peak (3600 cm ⁻¹ ) of the phenolic hydroxyl group disappeared by IR analysis. Absorption peak of the absorption peak (1405cm ^-1) and 1760 cm ^-1 to the carbonyl of the vinyl group was observed in the reverse.
In addition, chlorine atoms were not present by the Beilstein test.

PPE resin (E)

Using the bifunctional PPE oligomer synthesized in Synthesis Example 2 of PPE resin (D) and maleic anhydride, the ends of the oligomer were made maleoyl in the same manner as in Synthesis Example 2. This resin was designated as PPE resin (E). This reaction can be obtained by simply heating to reflux with a methylene chloride solution.
From the IR analysis of the PPE resin thus obtained, the absorption peak (3600 cm-1) of the phenolic hydroxyl group disappeared. At the same time, peaks of carbonyl groups from carboxylic acid and ester bonds appeared at 1680 and 1750 cm ⁻¹ .
Both were free of halogen atoms by the Beilstein test.
Moreover, PPE resin (F) is obtained by esterifying PPE resin with ethanol.

PPE resin (F)

(Synthesis Example 3)
PPE resin (G)

  CuL 1.3g (0.013 mol), di-n-butylamine 79.5g (0.62 mol), and methyl ethyl ketone 600cc were charged in a 2L vertical reactor equipped with a stirrer, thermometer, air inlet tube and baffle, and the reaction temperature was 40 ° C. The divalent phenol 2,2 ', 3,3', 5,5'-hexamethyl- [1,1'-biphenyl] -4,4'- previously dissolved in 600 cc of methyl ethyl ketone A mixed solution of 27.9 g (0.10 mol) of diol and 105.5 g (0.8 mol) of 2,3,6-trimethylphenol was added dropwise over a period of 120 minutes while bubbling 2 L / min of air, and 30 minutes after the completion of the addition. Stirring was continued while bubbling air at 2 L / min. Ethylenediaminetetraacetic acid dihydrogen disodium aqueous solution was added thereto to stop the reaction. Then, after washing 3 times with 1M hydrochloric acid aqueous solution, it was washed with ion-exchanged water. The obtained solution was concentrated with an evaporator, washed with ethanol, and dried under reduced pressure to obtain 117.9 g. This had a number average molecular weight of 1970, a weight average molecular weight of 2430, and a hydroxyl group equivalent of 440.

  The white powder bifunctional PPE oligomer 51.0 g (hydroxyl group 0.070 mol) and triethylamine 13.1 g (0.129 mol) thus obtained were dissolved in 250 cc of methyl ethyl ketone. Next, the reactor equipped with a stirrer, thermometer, and dropping funnel was cooled to −10 ° C., and 200 ml of a solution of 13.8 g (0.150 mol) of acryloyl chloride in methylene chloride was added to the reaction solution from the dropping funnel. The solution was added dropwise over 60 minutes so that the temperature was 10 ° C. or lower, and further stirred for 60 minutes after the completion of the addition. Thereafter, this reaction solution was washed three times with a 0.1N aqueous hydrochloric acid solution, washed with ion-exchanged water, and filtered to remove the generated salt and impurities. Next, methylene chloride and methyl ethyl ketone were distilled off from the resulting solution, washed with methanol, and dried under reduced pressure to obtain 4 g of acrylic powder 43 as white powder.

In the obtained product, the absorption peak (3600 cm ⁻¹ ) of the phenolic hydroxyl group disappeared by IR analysis. Conversely, an absorption peak (1405 cm ⁻¹ ) of vinyl group was observed.
Chlorine atoms were not present by the Beilstein test.

The bifunctional PPE oligomer (hydroxyl 0.05 mol) used in Synthesis Example 3 was synthesized as acryloyl chloride 5.4 g (0.06 mol). Similarly, 25.8 g of white powder was obtained by post-treatment. Absorption peak (1760 cm ^-1) both of the carbonyl group which in the absorption peak of the phenolic hydroxyl groups by IR analysis (3600 cm ^-1) were observed. This resin was found to have unreacted phenolic hydroxyl groups remaining. (This resin is called PPE resin (H).)

Other PPE resins can be easily obtained according to the above synthesis examples.
As can be seen from the above synthesis examples, it is more preferable that it is easily soluble in ketone solvents, and particularly easily soluble in non-hydratable methyl ethyl ketone, methyl propyl ketone, and further ethyl acetate, propyl acetate and the like. . It has good solubility in methylene chloride, ethane dichloride, tetrahydrofuran, monochlorobenzene and the like that have been often used.
These organic solvents can be used in combination of two or more, and are appropriately selected depending on the concentration of the coating solution, the drying conditions, and the required film properties of the photosensitive layer.

  A mixed solvent may be preferable because it can further improve the solubility of the main components of the photosensitive layer such as a charge generation material and a charge transport material. Ultimately, when considering various conditions such as health and safety, electrophotographic characteristics and cost, ethyl acetate alone, methyl ethyl ketone alone, or these solvents have a low evaporation rate and low hydration, such as propyl acetate Particularly preferred are ketone solvents, ester solvents such as butyl acetate, and mixed solvents with alcohol solvents such as butyl alcohol.

In recent years, function-separated type photoconductors are widely used as photoconductors for copying machines and printers. The structure of the function-separated type photoreceptor basically includes a conductive support, a charge generation layer mainly composed of a charge generation material as a photosensitive layer, and a charge transport (movement) material on the charge generation layer. It has a function-separated layered structure in which a charge transporting (moving) layer mainly composed of is formed.
The charge generation layer has a function of efficiently generating charges by light energy in a target wavelength region, and the charge transport layer has a function of efficiently transporting charges generated from the charge generation layer below the charge generation layer. If the charge transport material itself is a polymer type compound, it is not necessary to use a binder resin, but no polymer type transport compound exceeding the low molecular type has been found in terms of performance such as charge transport efficiency. Therefore, a low molecular type compound must be used to form the charge transport layer, and a binder resin is indispensable.

Therefore, the resin of the present invention is particularly suitably used as a binder resin for charge transport materials. In this case, the proportion of PPE resin is suitably between 40% and 60%. When the content is low, the charge transporting material is precipitated. On the other hand, when the content is high, the electrophotographic characteristics are deteriorated (sensitivity is decreased). The PPE resin of the present invention can also be used as a binder resin for a charge generation layer. In this case, it is important that the interface between the charge generation layer and the transport layer is aligned, and the proportion of the PPE resin in the charge generation layer is preferably 30% or less. By including the PPE resin in both the generation layer and the transport layer, the adhesion between the layers is improved.
Further, a binder resin in a single-layer type photosensitive member comprising a single photosensitive layer containing a charge generating material and a charge transporting material, or a photosensitive member in which an intermediate layer is provided between the conductive support and the photosensitive layer. Can also be used.

The conductive support in the photoreceptor of the present invention is not particularly limited as long as it is usually used as this type of conductive support. As the material, for example, the support itself has conductivity, for example, aluminum, aluminum alloy, copper, zinc, stainless steel, nickel and titanium can be used, and in addition, aluminum, gold, Examples include plastics (e.g., polyethylene) deposited with silver, copper, palladium, zinc, nickel, titanium, indium oxide or tin oxide, paper, plastics containing conductive polymers, etc. And sheet-like and seamless belt-like ones.
Next, other materials used for the photoreceptor of the present invention will be described. Examples of the charge generating material for the photoreceptor of the present invention include known compounds, that is, azo pigments such as bisazo pigments and trisazo pigments, phthalocyanine pigments such as metal-free phthalocyanine pigments and titanium phthalocyanine pigments having different crystal structures. A pigment or the like is used.

The charge generation material has a function of generating charges in the intended photosensitive region of the photoreceptor, and is appropriately selected depending on the use of the photoreceptor. In general, azo pigments are preferred for copying machine applications, and phthalocyanine pigments are preferred for printer applications. These pigments are usually dispersed in a fine powder state of 0.01 μ to 0.2 μ.
As the charge transporting material, a monohydrazone compound, a bishydrazone compound, a triphenylamine compound, an enamine compound, or a compound in which these are combined, which are known compounds in patents or the like, are used. Specific examples include monohydrazone + bisenamine compounds and dienamine compounds described in Examples below. In particular, a compound having an enamine has good transport efficiency and excellent thermal stability.
Next, the method for forming a photoconductor of the present invention will be described by taking a function separation type photoconductor as an example.

(Formation of charge generation layer)
The charge generation layer can be formed by normally dispersing the charge generation material in an alcohol, ketone or ester solvent, and coating the obtained dispersion on a conductive support. The binder resin is not always necessary, but it is also necessary to add it for the dispersion stability of the charge generating material and further the adhesiveness. For this reason, the ratio to be added is preferably 30% or less, and a resin having a functional group is preferable from the adhesion to the substrate, and the PPE resin of the present invention is also preferable as the resin for the charge generation layer. In particular, those in which R2 is —COOH (PPE resin (E)) are excellent in dispersibility and adhesion (injection efficiency).

Specifically, a charge generation layer is formed by adding a solution in which a binder resin is dissolved in a charge generation material, and then pulverizing and dispersing with a ball mill, dyno mill, lab mill, sand grinder, paint shaker (paint conditioner), or ultrasonic disperser. In the case of a sheet, the coating solution obtained by application is applied by a method such as applicator, dip, bar coater, casting and spin coating, and in the case of a drum by the spray method, vertical ring method or dip coating method. A generation layer is formed. In preparing the coating liquid, the dispersed particles may be adjusted by filtering as necessary.
As binder resins other than the resin of the present invention, known binder resins such as copolymer nylon, polyvinyl butyral, polyester, polyvinyl acetate, polyacrylate ester, polymethacrylate ester, polycarbonate, polyvinyl acetoacetal, phenoxy resin, Epoxy resins, urethane resins, cellulose esters, cellulose ethers, vinyl chloride-vinyl acetate copolymers, and the like can be used. You may mix and use these resin and PPE resin of this invention. Among these known phenoxy resins having a structural formula relatively close to that of the PPE resin of the present invention is particularly preferable.

Solvents for the charge generation layer include ketone solvents such as acetone, ethyl methyl ketone, methyl isobutyl ketone and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; ether solvents such as tetrahydrofuran and dioxane; alcohols such as ethanol A solvent having low toxicity such as a system solvent can be used.
The mixing ratio of the binder resin and the charge generating material in the charge generation layer is appropriately selected according to the type of each component and the performance required for the photoreceptor. The film thickness of the charge generation layer is usually about 0.1 to 0.5 μm. Note that the thinner the film thickness, the better, from the viewpoint of preventing charge trapping.
However, if the thickness is too thin, the optical density becomes insufficient.

(Formation of charge transport layer)
Next, a charge transport layer is formed on the charge generation layer.
The charge transport layer can be formed by a known method in the same manner as the charge generation layer.
For example, the charge transport material is dissolved in the above-mentioned solvent (particularly methyl ethyl ketone, n-butyl alcohol, ethyl acetate, amyl acetate, etc.), and the PPE resin of the present invention is added as a binder resin thereto, and the resulting solution is added to the charge generation layer. After applying to a sheet or drum in the same manner as in, drying, the PPE resin is crosslinked (three-dimensional) by annealing to form a charge transport layer. At this time, a polymerization initiator such as benzoyl peroxide (BPO), lauryl peroxide (LPO), AIBN or the like may be added to the PPE resin in an amount of 1% or less in order to promote crosslinking. As a result, the vinyl group at the end of the PPE resin of the present invention effectively works to promote crosslinking.

By cross-linking, the film strength is improved, but when the cross-linking is large, the adhesiveness tends to be slightly deteriorated. For this reason, you may blend with other PPE resin which is not this invention.
The thickness of the charge transport layer is usually about 10 to 50 μm from the charge retention thickness (chargeability). It goes without saying that a thicker film is better from the standpoint of printing durability.
Typical charge transport materials are described in Advanced Organic Material R & D Report (Fuji Chimera Research Institute). Of these, monoenamine, dienamine, and bisenamine compounds described in JP-A-6-43674, 130697, 332204, 332205, 110229, and JP-A-7-134430, 14673 are preferable materials from the viewpoint of transport efficiency.

The blending ratio of the binder resin and the charge transport material in the charge transport layer is appropriately selected depending on the type of each blend component and the performance required for the electrophotographic photoreceptor. The PPE resin of the present invention is characterized by having a self-crosslinking property, and therefore has mechanical strength for its molecular weight. For this reason, the ratio may be almost the same as the conventional binder resin (1: 0.8 to 0.8: 1 weight ratio).
You may add various additives, such as a leveling agent, antioxidant, and a trap prevention agent, to a charge generation layer and / or a charge transport layer as needed. Examples of the antioxidant include vitamin E, hydroquinone, hindered amine, hindered phenol, paraphenylenediamine, arylalkane and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds. Examples of the trap preventing agent include naphthyl cyanide, benzyl cyanide and derivatives thereof. As the leveling agent, anionic and nonionic fluorosurfactants commercially available from Kao are typically used.
In some cases, the surface wear may be prevented by providing an overcoat layer known as the outermost surface layer on the charge transport layer, for example, a thermoplastic or thermosetting polymer.

EXAMPLES The present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
Example 1
A polyester film (film thickness of 80 μm) on which an aluminum vapor deposition film was formed was used as a conductive support. On this, 0.5 g of a bisazo pigment represented by the following structural formula (1) was added as a charge generation material to 30 cc of a 1% methyl ethyl ketone solution in which PPE resin (E) was dissolved. The obtained solution was subjected to a dispersion treatment for about 30 minutes together with 100 g of glass beads having a diameter of 1.5 mm in a paint conditioner (manufactured by Red Devell), and filtered through a sieve to remove the glass beads. The obtained dispersion was applied on the conductive support by the application method and dried by heating at 60 ° C. for 30 minutes to form a charge generation layer having a thickness of 0.3 μm.
Structural formula (1)

  Next, 1 g of PPE resin (D) of Synthesis Example 2 was dissolved in 10 cc of methyl ethyl ketone at room temperature, and 0.9 g of a monoenamine: hydrazone compound represented by the following structural formula (2) was further dissolved. The obtained solution is immediately applied onto the above-described charge generation layer by an application method, dried at room temperature, and then dried (annealed) at a temperature of 100 ° C. for about 30 minutes to charge transport with a film thickness of 35.0 μm. A layer was formed. As described above, a sheet-like function-separated electrophotographic photosensitive member composed of a charge generation layer and a charge transport layer was obtained.

Structural formula (2)

The electrophotographic characteristics of the obtained photoreceptor were evaluated with an electrophotographic measuring apparatus (manufactured by Green Electric Co., Ltd., SP-428). Measurement conditions were applied voltage: −5 KV and light source: tungsten lamp. V ₀ represents an initial potential (volt), and V _R represents a potential (volt) after irradiation for 0.2 seconds at 50 lux.
Further, charging and exposure were repeated 500 times continuously under the conditions of applied voltage: −5 KV and neutralizing light 200 lux, and at this time, the potential drop and the residual potential rise were examined.
As a result, V ₀ was −630V and V _R was −7V. The V ₀ which after repeated in successively charged + exposure 500 times -655V, V _R was found to be a photoreceptor having a high sensitivity and stable repetition characteristics be -25V.

であるＰＰＥ樹脂（D'）（分子量3300）をそれぞれ電荷輸送材料として用いる以外は、実施例１と同様にして、シート状の機能分離型電子写真感光体を得た。得られた感光体の電子写真特性を、実施例１と同様にして評価した。得られた結果を表１に示す。

尚、実施例４の電荷輸送材料は下記構造式（３）で示されるジエナミン化合物を用いた。
構造式（３）

これら各感光体は優れた電子写真特性を示しており、また接着性においても良好であった。 Examples 2-4
Instead of PPE resin (E) in Synthesis Example 2, PPE resins (A) (B) and X

A sheet-like function-separated electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that PPE resin (D ′) (molecular weight 3300) was used as the charge transport material. The electrophotographic characteristics of the obtained photoreceptor were evaluated in the same manner as in Example 1. The obtained results are shown in Table 1.

The charge transport material of Example 4 was a dienamine compound represented by the following structural formula (3).
Structural formula (3)

Each of these photoreceptors exhibited excellent electrophotographic characteristics and good adhesion.

Examples 5-7
In the same manner as in Example 1, except that PPE resins (C), (E), and (H) are used as the charge transport binder resin materials instead of the PPE resin (D) of Synthesis Example 2, respectively, Thus, a function-separated type electrophotographic photosensitive member was obtained. The electrophotographic characteristics of the obtained photoreceptor were evaluated in the same manner as in Example 1. The obtained results are shown in Table 2.

As a binder resin for the charge generation layer in Table 2, a copolymer resin (acidity 23) mainly composed of vinyl acetate was used instead of the PPE resin (E).
Any of the above photoreceptor sheets was in no way inferior to the one obtained by sealing our photoreceptor in a peel test using a cellophane tape.
Each of these photoreceptors showed excellent electrophotographic characteristics from Table 2, and also had good adhesion. In particular, the electrophotographic characteristics (residual potential) of the photoreceptor using PPE resin (E) as the binder resin of the charge generation layer have a tendency to be better from Tables 1 and 2 (Table 1 has slightly better data). Has a tendency.).

  It can be seen that even the PPE resin (H) whose terminal group is not sufficiently carbonylated exhibits excellent electrophotographic characteristics.

Example 8
The solubility of the PPE resins of Synthesis Examples 1 to 3 and the PPE resins used in Example 4 (9 types from A to H and D ′) was examined.
Solubility conditions are as follows: 1 g of resin is placed in 10 cc of solvent and forcibly dissolved by ultrasound at 50 ° C., and then this solution is left in a refrigerator at 5 ° C. for a whole day and night. And gelation changes were investigated.

Solvents used in the investigation were acetone and methyl ethyl ketone as ketone systems, ethyl acetate and propyl acetate as ester systems, methanol and n-butyl alcohol as alcohol systems, and dichloroethane and toluene in addition to these.
As a result, the solubility was good except for methanol. However, although the PPE resin solution of Synthesis Example 1 turned cloudy to gel with n-butyl alcohol, a system in which 5 cc of methyl ethyl ketone was added became a homogeneous solution, and there was no problem in solubility.
As a comparative example, polycarbonate Z (manufactured by Mitsubishi Gas Chemical Co., Ltd.), which is often used as a charge transporting resin at present, was examined for the same solubility, and other than toluene and dichloroethane did not dissolve even at 50 ° C. From this, it was found that the PPE resin of the present invention dissolves well in a solvent having few problems in toxicity and safety.

  The photoconductor of the present invention can be suitably used for those having a photoconductor other than a copying machine and a printer.

Claims (8)

On a conductive support and at least an organic photoconductive material as the electrophotographic photosensitive member photosensitive layer comprising a binder resin is formed, the binder resin, one of its terminal least the following general formula (1 :

(In formula (1), R ₁ is hydrogen or a methyl group, and R ₂ is hydrogen, a methyl group, a carboxy group or an ester group thereof.)
In PPE (polyphenylene ether) that is a carbon atom and an ether bond shown to methylene electrophotographic photoreceptor which is a resin. The PPE resin has the following general formula (2) :

(In the formula (2), X and Y are divalent residues having an aromatic carbon atom as a bond, and R ₁ and R ₂ have the same meanings as in the formula (1). (It is an integer from 0 to 300, one of which is not 0.)
Electronic photosensitive member according to claim 1 PP Ru E tree Aburadea shown in. The electrophotographic photoreceptor of Y is described in 請 Motomeko 2 PPE resin der Ru consisting phenylene group substituted with a lower alkyl group having from 1 carbon atoms ortho-substituted 4 of the PPE resin. The PPE X is 4,4 'positions substituted biphenylene group of the resin, electrophotographic photosensitive member according to 請 Motomeko 2 PPE resin der Ru consisting phenylene 1,4-substituted. X of the PPE resin is represented by the general formula (3) :

(In the formula (3), Ar is a substituted or unsubstituted phenylene group, R ₃ and R ₄ are hydrogen, a lower alkyl group having 1 to 4 carbon atoms or a substituted or unsubstituted phenyl group, and further R ₃ R ₄ may be bonded to each other to form a 5-membered or 6-membered ring structure.)
The electrophotographic photosensitive member according in the 請 Motomeko 2 PPE resin der Ru consisting bisphenylene group represented. In the electrophotographic photosensitive member having a structure in which the charge generation layer and the charge transport layer are functionally separated, the PPE resin according to any one of claims 1 to 5 is used as a binder resin for the charge transport layer. Electrophotographic photoreceptor. In an electrophotographic photosensitive member having a structure in which a charge generation layer and a charge transport layer are functionally separated, the PPE resin according to any one of claims 1 to 5 is used as a binder resin for the charge transport layer and the charge generation layer. An electrophotographic photoreceptor characterized by the above. In the electrophotographic photoreceptor of the functionally separated into a charge transport layer and charge generating layer structure, an electrophotographic photosensitive described 請 Motomeko 6 or 7 that contain the compound in the charge transport layer is having at least one enamine group body.