JP4059865B2 - Environmentally-friendly electrophotographic photoreceptor - Google Patents

Description

The present invention relates to an environmentally friendly electrophotographic photosensitive member containing a PPE resin having a specific structure as a binder resin for a photosensitive layer.
More specifically, by using a specific resin decorated with a cyano group at the PPE resin terminal, electrophotographic performance (especially repetitive characteristics) can be achieved without using halogen solvents such as methylene chloride and aromatic solvents such as xylene and toluene. The present invention relates to the preparation of a photoreceptor excellent in sensitivity characteristics.

In recent years, electrophotographic technology is 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, the photoreceptor 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 (charge transport materials, charge generation materials, binder resins, etc.) dissolved or dispersed in an appropriate solvent in an organic solvent.
Conventionally, the most important point in developing materials such as a charge generating material and a charge transporting material for a photoconductor is to improve the functionality of the photoconductor and 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, OPC material development in this field (mainly low molecular weight compounds) is thriving, and new material development has been vigorously advanced.
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 emphasizing improvement in the functionality of the photoreceptor, an existing so-called thermoplastic engineer is used. Development has been carried out mainly for ring 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. The polycarbonate resin body is a resin that is used for glass materials and the like and has no problem in terms of safety and hygiene. 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 a low molecular weight (1000 to 5000), and chemical treatment from a specific structure (introduction of a long-chain alkyl group into the side chain) can improve solubility. However, by taking these measures, the mechanical strength is lowered (decrease in wear resistance), the charge transport material is deposited and made non-uniform, resulting in insufficient charging, reduced sensitivity, and further reduced printing durability. Such problems arise.

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 sanitary health hazard (organic solvent worker text: edited by the Ministry of Health, Labor and Welfare, Occupational Health Division) and are not preferred solvents.
On the other hand, ether solvents such as tetrahydrofuran are relatively low in toxicity, but there is a risk of oxidative explosion due to ether bonds, and further, moisture is taken up in the atmosphere due to heat of vaporization during drying based on the magnitude of water absorption. This is likely to cause deterioration of the film characteristics.

  The present invention does not use a halogen-based solvent, an aromatic solvent, or an ether-based solvent as a solvent during coating formation of the photosensitive layer, and functions equivalent to or higher than conventional ones (printing durability, high sensitivity, It is an object to obtain a high-performance photoreceptor having high chargeability.

  The present invention relates to 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, wherein the binder resin is decorated with at least one terminal by a cyano group. The above-mentioned problems have been solved by providing an electrophotographic photosensitive member characterized by being a PPE (polyphenylene ether) resin.

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.
Further, by heating the PPE resin of the present invention, a photoreceptor excellent in heat resistance and wear resistance could be obtained.
Thus, the photoreceptor of the present invention could 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 inventors have used a specific PPE (polyphenylene ether) resin as a binder resin to be used for coating formation of the photosensitive layer. The photosensitive layer can be formed by using an environmentally friendly organic solvent, and as a result, a photosensitive member with high sensitivity, high charging performance, and excellent wear resistance can be obtained. I understood it. The PPE resin of the present invention is also a novel material as a binder resin for an electrophotographic photoreceptor.

（式１中、X、Yは置換、非置換の２価のビフェニレン基、ビスフェニレン基、フェニレン、ナフチレン基であり、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。） Specifically, a PPE (polyphenylene ether) resin in which at least one terminal is decorated with a cyano group is used as a binder resin for an electrophotographic photoreceptor. In particular, among these resins, a PPE (polyphenylene ether) resin represented by the following general formula (1) is used as a binder resin.
General formula (1)

(In Formula 1, X and Y are substituted or unsubstituted divalent biphenylene group, bisphenylene group, phenylene and naphthylene group, and n and m are integers of 0 to 300, at least one of which is not 0. is there.)

  Describing the general formula (1), 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 by a single bond, and a representative example is a biphenylene group at the 4 and 4 'positions. 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 (bisphenol) And Z).

において、Ｒ１とＲ２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。 In particular, among the resins of the general formula (1), a PPE resin having a weight molecular weight of about 1000 to 10,000, in which X is a bisphenylene group (there are two same substituents centered on carbon atoms and oxygen atoms), It is preferable from the viewpoint of solubility, electrophotographic characteristics, and the like. In terms of the relationship between improved solubility and chemical structure, the general formula (2)

6 having a structure in which R1 and R2 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, and 5 A monocyclic ring having a member ring tends to be good.

In relation to the molecular weight, when the molecular weight is low, the film properties are deteriorated, and when the molecular weight is large, by-products are likely to be formed, and it is difficult to obtain stable electrophotographic performance. For this reason, 2 to 10 are appropriate for n and m. In addition, a single PPE resin represented by H— (Y—O—) m—CN or the like is easily produced, which causes deterioration of solubility in ketone solvents. 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 does not significantly affect the solubility if a small amount of single PPE resin remains. 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 or ethyl group substituted or unsubstituted group, and is particularly preferably ortho-substituted methyl or dimethyl substituted in terms of synthesis (it is difficult to produce a by-product).

  Some of these PPE resins of the present invention are described in JP-A Nos. 2003-12796 and 2003-155340. In addition, description about 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 by substantially the same production method. As synthesis means, firstly, H — (— O—Y) n —O—X—O— (Y—O—) m—H was synthesized, and then a methylene chloride solution of chlorocyan was added to pyridine, organic amine. For example, it can be obtained by cyanation by acting triethylamine as a catalyst. The synthesis of the PPE resin of the present invention does not need to be performed under special conditions such as an inert gas atmosphere under reduced pressure. Also, the reactivity is good, so that the synthesis yield exceeds 95%.

Here, the synthesis of a typical PPE resin 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)
Manufacture of bifunctional PPE oligomers (the following structural formula)
(N and m are integers of 10 or less)

  CuCl 1.3g (0.013 mol), n, n-dibutylamine 79.2g (0.62 mol), and methyl ethyl ketone 700cc were charged in a 2-liter vertical reactor equipped with a stirrer, thermometer, air inlet tube and baffle plate. Stir at a temperature of 40 ° C, and bisphenol A (2,2'-bis (4-hydroxyphenyl) propane) 33, 2 g (0.15 mol) and 2,6-dimethylphenol dissolved in 500 cc of methyl ethyl ketone in advance. 75.6 g (0.62 mol) of the mixed solution 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. . To this solution, an aqueous solution of disodium ethylenediaminetetraacetate was added to stop the reaction. Then, after washing 3 times with 1M hydrochloric acid aqueous solution, it was washed with ion-exchanged water. The obtained methyl ethyl ketone solution was concentrated with an evaporator, washed with alcohol, and dried under reduced pressure to obtain 103.2 g of a white powder. This had a number average molecular weight of 1150, a weight average molecular weight of 1470, and a hydroxyl group equivalent of 580.

Production of Cyanate Body A reactor equipped with a stirrer, a thermometer and a dropping funnel was cooled to −10 ° C., and 200 cc of a methylene chloride solution of chlorocyan (0.129 mol) was charged. Thereafter, a solution in which 50.0 g (hydroxyl group 0.086 mol) of the bifunctional PPE oligomer obtained above and 13.1 g (0.129 mol) of triethylamine was previously dissolved in 250 cc of methyl ethyl ketone was added from a dropping funnel, and the temperature of the reaction solution became 10 ° C or lower. The mixture was added dropwise over 60 minutes, and further stirred for 60 minutes after completion of the addition. Thereafter, the resulting salt and impurities were removed by washing with 0.1N aqueous hydrochloric acid solution three times, with ion-exchanged water and filtration. Methylene chloride and methyl ethyl ketone were distilled off from the resulting solution, followed by drying under reduced pressure, followed by hot washing with alcohol to obtain 50.1 g of a cyanate compound. The resulting powder, absorption peaks of the phenolic hydroxyl group (3600 cm ^-1) disappears by analysis of IR (KRS method), the absorption peak derived from cyanate group (2250 cm ^-1) was expressed. This confirmed 100% functional group conversion.

(Synthesis Example 2)
Manufacture of bifunctional PPE oligomers (the following structural formula)
(N and m are integers of 10 or less)

  CuCl 1.3g (0.013 mol), n, n-dibutylamine 79.5g (0.62 mol), and methylethylketone 600cc are charged into a 2 liter vertical reactor equipped with a stirrer, thermometer, air inlet tube, and baffle plate. The mixture was stirred at 40 ° C. and 42.8 g (0.15 mol) of bisphenol Z (1,1′-bis (4-hydroxyphenyl) cyclohexane) dissolved in 700 cc of methyl ethyl ketone in advance and 75.6 g of 2,6-dimethylphenol ( 0.62 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 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 resulting solution was concentrated with an evaporator, further washed with alcohol and dried under reduced pressure to obtain 116.6 g of a white powder. This had a number average molecular weight of 1160, a weight average molecular weight of 1390, and a hydroxyl group equivalent of 520.

Production of Cyanate Body A 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 chlorocyan (0.129 mol) was charged. Thereafter, 50.0 g (hydroxyl group 0.086 mol) of the bifunctional PPE oligomer obtained above was dissolved in a solution prepared by dissolving 13.1 g (0.129 mol) of triethylamine in 300 cc of methyl ethyl ketone in advance, and this was added from the dropping funnel to the temperature of the reaction solution. Was added dropwise over 60 minutes so that the temperature became 10 ° C. or lower, and further stirred for 60 minutes after the completion of the dropwise addition. Thereafter, the resulting salt and impurities were removed by washing with 0.1N aqueous hydrochloric acid solution three times, with ion-exchanged water and filtration. Methylene chloride and methyl ethyl ketone were distilled off from the resulting solution, followed by drying under reduced pressure to obtain 50.1 g of a cyanate compound. As for the obtained product, the absorption peak of phenolic hydroxyl group (3600 cm ^-1 ) disappears by IR analysis, and the absorption peak derived from cyanate group (2250 cm ^-1 ) is expressed. Confirmed conversion.

(Synthesis Example 3)
Manufacture of bifunctional PPE oligomers (the following structural formula)
(N and m are integers of 10 or less)

CuCl 1.3g (0.013) is added to a 2L vertical reactor equipped with a stirrer, thermometer, air inlet tube and baffle plate.
mol) and di-n-butylamine 79.5 g (0.62 mol) methyl ethyl ketone 600 cc, stirred at a reaction temperature of 40 ° C., and previously dissolved in 600 cc methyl ethyl ketone 2,2 ', 3,3 A solution of 41.8 g (0.15 mol) of ', 5,5'-hexamethyl- [1,1'-biphenyl] -4,4'-diol and 86.7 g (0.70 mol) of 2,6-dimethylphenol was 2 L / min. The mixture was added dropwise over 120 minutes while bubbling air, and further stirred for 30 minutes after 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 and further dried under reduced pressure to obtain 121.9 g. This had a number average molecular weight of 1200, a weight average molecular weight of 1450 and a hydroxyl group equivalent of 520.

Production of Cyanate Body A reactor equipped with a stirrer, a thermometer, and a dropping funnel was cooled to −10 ° C., and 200 cc of a methylene chloride solution of chlorocyan (0.144 mol) was charged. Thereafter, a solution prepared by dissolving 50.0 g of the above oligomer (0.096 mol of hydroxyl group) and 14.6 g (0.144 mol) of triethylamine in 250 cc of methyl ethyl ketone in advance was dropped from the dropping funnel over 60 minutes so that the temperature of the reaction solution was 10 ° C. or less. Further, the mixture was stirred for 60 minutes after completion of the dropwise addition. Thereafter, the resulting salt and impurities were removed by washing with 0.1N aqueous hydrochloric acid solution three times, with ion-exchanged water and filtration. Methylene chloride and methyl ethyl ketone were distilled off from the resulting solution, followed by drying under reduced pressure to obtain 50.8 g of a cyanate compound. As a result of the IR analysis, the absorption peak of phenolic hydroxyl group (3600 cm ^-1 ) disappeared and the absorption peak derived from cyanate group (2250 cm ^-1 ) was expressed. It was confirmed.

(Synthesis Example 4)
Production of bifunctional PPE oligomer (Structural formula: same as Synthesis Example 2)
(N and m are integers of 10 or less)
An oligomer was synthesized according to Synthesis Example 2. The amount of 1,1′-bis (4-hydroxyphenyl) cyclohexane was halved to 21.4 g, so that the ratio to 2,6-dimethylphenol was approximately 1: 8. The post-treatment and the like were also the same as in Synthesis Example 2. This had a number average molecular weight of 3,100, a weight average molecular weight of 3,780, and a hydroxyl group equivalent of 340.
By reducing the proportion of 1,1′-bis (4-hydroxyphenyl) cyclohexane, a PPE oligomer having a higher molecular weight was obtained.

Production of Cyanate Body A cyanate body was synthesized according to Synthesis Example 2. The resulting white powder, since the absorption peak of the phenolic hydroxyl group (3600 cm ^-1) disappears, the absorption peak derived from cyanate group (2250 cm ^-1) is expressed by analysis of IR, 100% of the functional groups Confirmed conversion.
In this way, a cyanate compound having the same structure as that of Synthesis Example 2 and a molecular weight of almost twice was obtained.
Other PPE resins can be easily obtained according to the above synthesis examples.
As can be seen from the synthesis examples, it is more preferable that the compound is easily soluble in a ketone solvent, and particularly easily soluble in methyl ethyl ketone, methyl propyl ketone, ethyl acetate, propyl acetate and the like having low hydration property. It has good solubility in methylene chloride, ethane dichloride, tetrahydrofuran, benzene chloride 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 is basically formed on a conductive support, a charge generation layer mainly composed of a charge generation material as a photosensitive layer, a charge transport layer formed on the charge generation layer, and charge transport. It has a function-separated laminated structure in which a charge transporting (moving) layer mainly composed of a (moving) material 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 to laminate the interface between the charge generation layer and the transport layer so that 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.
Specific examples include bisazo pigments described in Examples 1 to 3 below and titanium oxide phthalocyanine described in Example 4. 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.

  As the charge transport material of the photoreceptor of the present invention, monohydrazone compounds, bishydrazone compounds, triphenylamine compounds, enamine compounds, and compounds in which these are combined, which are known compounds in patents, etc. are used. Specifically, the monohydrazone + bisenamine compound described in Examples 1 to 3 described later, the dienamine compound described in Example 4, and the like can be given.

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.

  For example, a solution in which a binder resin is dissolved in a charge generating material is added, and a coating liquid obtained by pulverizing and dispersing with a ball mill, dyno mill, lab mill, sand grinder, paint shaker (paint conditioner) or ultrasonic disperser is used as a sheet. In the case of (1), the charge generation layer is formed by coating by a method such as an applicator, dip, bar coater, casting and spin coating, and in the case of a drum (spray method, vertical ring method and dip coating method). In preparing the coating liquid, the dispersed particles may be adjusted using a filter as necessary.

The binder resin is not limited to the PPE resin of the present invention, and known binder resins such as copolymer nylon, polyvinyl butyral, polyester, polyvinyl acetate, polyacrylic acid ester, polymethacrylic acid ester, polycarbonate, and polyvinyl acetoacetal. Phenoxy resin, epoxy resin, urethane resin, cellulose ester, cellulose ether, vinyl chloride-vinyl acetate copolymer, and the like can be used. You may mix and use these resin and PPE resin of this invention. Among these, a phenoxy resin 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.

(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 charged. The charge transport layer is formed by applying to a sheet or drum in the same manner as for the layer, and optionally drying or partially crosslinking (three-dimensional) the PPE resin by annealing. Although only drying may be sufficient, the terminal cyano group is radicalized by reheating at 120 to 200 ° C. after the drying, and thereby the crosslinking proceeds. By cross-linking, the film strength is improved, but when the cross-linking is large, the adhesiveness tends to be slightly deteriorated.

The optimal degree of crosslinking is 1-30%. The thickness of the charge transport layer is usually about 10 to 40 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). Among these, monoenamine, dienamine, and bisenamine compounds described in JP-A-6-43674, 130697, 332204, 332205, 110229, JP-A-7-134430, 146754, and the like 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. Examples of the leveling agent include anionic and nonionic fluorosurfactants commercially available from Kao.
Wearing the surface 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 described more specifically with reference to examples. However, 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. 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 a PPE resin obtained by cyanating the terminal obtained in Synthesis Example 2 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 an application method and dried to form a charge generation layer having a thickness of 0.3 μm.

次いで、メチルエチルケトン１０ｃｃに、合成例３のＰＰＥ樹脂１ｇを室温下で溶解
し、さらに下記構造式（２）で表されるモノエナミン：ヒドラゾン化合物０．９ｇを溶解した。得られた溶液を直ちに上記の電荷発生層上にアプリケーション法により塗布し、室温で乾燥し、次いで温度８０℃で約３０分間アニールを行い、膜厚３５．０μｍの電荷輸送層を形成した。以上のようにして、電荷発生層と電荷輸送層から構成される、シート状の機能分離型電子写真感光体を得た。 Structural formula (1)

Next, 1 g of PPE resin of Synthesis Example 3 was dissolved in 10 cc of methyl ethyl ketone at room temperature, and 0.9 g of monoenamine: hydrazone compound represented by the following structural formula (2) was further dissolved. The obtained solution was immediately applied onto the charge generation layer by the application method, dried at room temperature, and then annealed at a temperature of 80 ° C. for about 30 minutes to form a charge transport layer having a thickness of 35.0 μm. As described above, a sheet-like function-separated electrophotographic photosensitive member composed of a charge generation layer and a charge transport layer was obtained.

得られた感光体の電子写真特性を、電子写真測定装置（緑電気社製、ＳＰ−４２８）により評価した。測定条件は、印加電圧：−５ＫＶ、光源：タングステンランプとした。Ｖ₀ は初期電位（ボルト）、Ｖ_R は５０ルックスで０．２秒照射後の電位（ボルト）を示す。
また印加電圧：−５ＫＶ、除電光２００ルックスの条件下において、500回連続して帯電+露光の繰り返しを行い、この時、電位低下、残留電位の上昇について調べた。
この結果、Ｖ₀ は−６３０Ｖであり、Ｖ_R は−５Ｖであった。また500回連続して帯電+露光の繰り返し後のＶ₀ は−６２０Ｖ、Ｖ_R は−１５Ｖであり高感度でかつ安定した繰り返し特性を有する感光体であることが判明した。 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 −5V. The V ₀ which after repeated in successively charged + exposure 500 times -620 V, V _R was found to be a photoreceptor having a high sensitivity and stable repetition characteristics be -15V.

であるＰＰＥ樹脂（分子量3100）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。 Examples 2-4
Instead of the PPE resin of Synthesis Example 3, the PPE resin of Synthesis Examples 1 and 4 and X

A sheet-like function-separated electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that PPE resin (molecular weight 3100) was used as a 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.

Table-1

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

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

Example 5
The solubility of the PPE resins of Synthesis Examples 1 to 4 and the PPE resins used in Example 4 (total 5 types) were examined.
The solubility condition was that 1 g of resin was placed in 10 cc of solvent and dissolved at 50 ° C. by ultrasonic waves. Thereafter, this solution was left in a refrigerator at 5 ° C. for a whole day and night, and the change in each solution was visually examined for occurrence of turbidity and gelation change.
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, when the same solubility was investigated for Polyca Z (manufactured by Mitsubishi Gas Chemical), which is often used as a charge transporting resin for photoreceptors, it was not dissolved at 50 ° C. except for dichloroethane. From this, it was found that the PPE resin of the present invention is a resin that dissolves well in various toxic and safety-friendly solvents.

  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)

An electrophotographic photosensitive member in which a photosensitive layer made of at least an organic photoconductive material and a binder resin is formed on a conductive support, wherein the binder resin is made of PPE (decorated with a cyano group at least one terminal). An electrophotographic photosensitive member characterized by being a polyphenylene ether) resin. 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, wherein the binder resin has a linear structure and both ends thereof are cyano groups. 2. The electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photosensitive member is a decorated PPE (polyphenylene ether) resin. 3. The electrophotographic photosensitive member according to claim 2, wherein the PPE (polyphenylene ether) resin is a resin represented by the following general formula (1):

(In Formula 1, X and Y are substituted or unsubstituted divalent biphenylene group, bisphenylene group, phenylene and naphthylene group, and n and m are integers of 0 to 300, at least one of which is not 0. is there.). 4. The electrophotographic photoreceptor according to claim 3, wherein the X and Y substituents are PPE resins comprising ortho-substituted lower alkyl groups having 1 to 4 carbon atoms. 4. The electrophotographic photosensitive member according to claim 3, wherein X is a PPE resin comprising a biphenylene group substituted at 4, 4′-position and a phenylene group substituted at 1,4-position. 4. The electrophotographic photosensitive member according to claim 3, wherein X is a PPE resin comprising a bisphenylene group represented by the general formula (2).

(In formula 2, Ar is a substituted or unsubstituted phenylene group, R 1 and R 2 are hydrogen, a lower alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted phenyl group, and R 1 and R 2 are bonded to each other. By doing so, a 5-membered ring or 6-membered ring structure may be formed.) An electrophotographic photosensitive member comprising a charge generation layer and a charge transporting layer having a functional separation structure, wherein the PPE resin according to claim 1 is used as a binder resin for the charge transporting layer. 8. The electron according to claim 7, wherein the electrophotographic photosensitive member having a functional separation structure in the charge generation layer and the charge transport layer contains a compound having at least one enamine group in the charge transport layer. Photoconductor.