JP2005141030A - Electrophotographic photoreceptor and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate free of cleaning defects in a cleaning step, in the manufacture of an electrophotographic photoreceptor. <P>SOLUTION: When a substrate for an electrophotographic photoreceptor is subjected to aqueous cleaning, in the final step of the cleaning, the substrate is exposed to steam and water produced by dew condensation on a substrate surface is evaporated with flow of air or by temperature rise, and then a photosensitive layer is formed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member mounted on a printer, a copying machine, or other electrophotographic equipment using electrophotographic technology.

  An electrophotographic photoreceptor comprises a photosensitive layer that forms a latent image by charging and exposure, and a substrate on which the photosensitive layer is provided.

  On the other hand, the electrophotographic photoreceptor is required to have sensitivity, electrical characteristics, and optical characteristics according to the applied electrophotographic process.

  Further, it is required that the characteristics are sufficiently exhibited in any environment from low temperature and low humidity to high temperature and high humidity, and that the image has no environmental defect. Typical image defects include image streaks, black spots on white areas, white spots on black areas, background fog on white areas, and the like.

  The occurrence of the image defects as described above can be caused by various defects in the photosensitive layer and defects in the substrate, and one of the factors that has a great influence is the surface condition resulting from the washed state of the substrate. That is, if stains or residues that may become electrical or shape defects remain after substrate cleaning, all of them are directly connected to image defects.

  In recent years, water-based cleaning has become common from an environmental and safety standpoint. It is no exaggeration to say that the key points for cleaning these water systems are concentrated in the water quality. In water-based cleaning, moisture is released from the substrate in the final cleaning step. However, if there is a problem with water quality, a non-uniform surface expressed as spots or spiders is generated on the substrate. If the stain is extreme, it may be observed as a residue. These stains, spiders, and residues remain after the photosensitive layer is formed, resulting in image defects when mounted on an electrophotographic apparatus. In order to prevent these defects, aqueous cleaning of the substrate requires the use of a large amount of pure water or ion-exchanged water, and requires a lot of effort in terms of management, and stable production with easy management that is less costly. A possible technology is required.

  As a result of investigations on these matters, after the substrate has been subjected to a water-based cleaning step, when the photosensitive layer is provided, the substrate is exposed to water vapor in the final cleaning step to cause dew condensation, and the resulting condensed water is flown or It has been found that by providing a photosensitive layer after removing by drying by heating, an electrophotographic photoreceptor free from image defects can be supplied more stably than in the prior art.

  That is, the action is as follows, and FIG. 1 shows an example of conventional cleaning. Conventional water-based cleaning is known in the art disclosed in Japanese Patent Laid-Open No. 00-0000000. If this is schematically shown, in conventional water-based cleaning, cleaning is usually performed by providing two or more water tanks and sequentially sending the substrate into the water tank. In the figure, three tanks are taken as an example. First of all, 1. Substrate should contain a surfactant. 3. Detergent tank. 2. Use a circulation pump to install a filter as necessary to clean and clean the surface of the substrate while separating and removing oil and deposits. Next, it is common to remove the surfactant in the rinsing tank, dry the water by raising the temperature of the hot water bath or the substrate in the final washing process, and use it in the next process. . Each of these tanks can be provided in three or more tanks, and if necessary, a temperature control system and an ultrasonic transmitter can be provided to control cleaning conditions, and a filter, pure water, or It is also an effective means to control the water quality by supplying ion exchange water.

  According to the present invention, as shown in the examples, after forming the electrophotographic photosensitive member, the substrate is subjected to a water-based cleaning step, and then when the photosensitive layer is provided, the substrate is exposed to water vapor in the final cleaning step to cause condensation. By removing and drying the generated condensed water by air flow or heating and then providing a photosensitive layer, it is possible to supply an electrophotographic photosensitive member having no image defects more stably than in the prior art.

  In the present invention shown in FIG. 2, instead of the conventional hot water washing tank, a 6. dew condensation tank using steam is provided, thereby producing an effect that is not found in the past. 1. The substrate that has undergone rinsing is vaporized on the surface in a dew condensation tank and wetted with dew condensation water, and the dew condensation water is blown off by a 7. air knife when leaving the tank. 6. The dew condensation tank has a structure in which boiling water is prepared at the bottom with a heater and water vapor without impurities is efficiently retained in the upper layer. 7. There are other means as long as the air knife has a structure in which condensed water is removed, and the object can be achieved even if the water is dispersed with hot air, for example.

  As a factor that finally exposes stains and spiders after washing, the water quality remaining on the substrate at the time of drying in the final process becomes dominant. If even a small amount of impurity components are contained in the moisture remaining at the time of drying, these will be deposited on the substrate, and rinsing with extremely high purity will be required.

  On the other hand, the method for drying condensed water by water vapor from the substrate of the present invention utilizes the fact that water vapor does not contain impurities, and even if water containing impurity components remains on the substrate in the rinse step, Therefore, in the subsequent drying, an effect close to that of evaporating pure water from the substrate can be obtained. In other words, even if the water quality of the washing machine that is used repeatedly deteriorates somewhat, it compensates for it and produces a sufficient effect.

  By these actions, the electrophotographic photosensitive member of the present invention provided with a photosensitive layer after the substrate is exposed to water vapor in the final step of water-based cleaning to cause condensation, and the resulting condensed water is removed by airflow or heating to dry. It is possible to stably obtain a good image quality free from image defects due to spots or spiders during substrate cleaning.

  The present invention will be described in more detail. As an example of a substrate, for example, an aluminum cylindrical substrate, an aluminum ingot is extruded and formed into a cylinder by drawing, and then the surface is cut and used as a substrate as an electrophotographic photosensitive member. Typical examples are so-called cutting pipes and mirror-cutting pipes obtained by further applying mirror finishing to the cutting pipes.

  On the other hand, an aluminum substrate that satisfies the dimensional accuracy without cutting finish for the purpose of reducing the cost is also known as follows. The aluminum plate is processed into a cup shape by deep drawing, and then the DI processing to produce a bottomed cylinder by ironing, the aluminum plate is processed into a cup by impact extrusion, and then the cup wall is extended by ironing to form a cylinder. There are known methods such as the II method for producing EI, the EI method for producing a thin cylinder by ironing the obtained cylindrical product after extrusion, and the ED method for producing a thin cylinder by further drawing after extrusion.

  When a photosensitive layer is formed by forming a photosensitive layer on these aluminum substrates, in an electrophotographic apparatus using coherent light as a light source, such as a laser beam printer or a digital copying machine, the light is interfered with light on the image. Interference fringes may occur and image quality may be impaired.

  In order to solve these problems on the image, it has been proposed that the surface of the substrate is appropriately roughened by spraying and irradiating the substrate with an abrasive such as honing or blasting, or abrasive grains. These treatments are effective means for preventing interference fringes by selecting appropriate conditions and for eliminating the cutting traces and marks of the substrate. For the same purpose, the surface of the substrate can be anodized.

  When the substrate is prepared, the photosensitive layer is formed through the cleaning means shown in the present invention.

  As the layer structure of the photoconductor, a charge generation layer and a charge transport layer are laminated in this order on an intermediate layer provided on a substrate as needed. Conversely, a charge transport layer and a charge generation layer are laminated in this order. There is what I did.

  The charge transport layer comprises a polycyclic aromatic compound having a structure such as biphenylene, anthracene, pyrene and phenanthrene in the main chain or side chain; a nitrogen-containing ring compound such as indole, carbazole, oxadiazole and pyrazoline; a hydrazone compound and styryl. It is formed by applying a solution in which a charge transport material such as a compound is dissolved in a resin having a film-forming property, and drying. Examples of the resin having film-forming properties include polyester, polycarbonate, polystyrene, polymethacrylic acid ester, polyarylate and the like.

  The thickness of the charge transport layer is preferably 5 to 40 μm, more preferably 10 to 30 μm.

  The charge generation layer is composed of azo pigments such as Sudan Red and Diane Blue; quinone pigments such as pyrene, quinone and anthanthrone; quinocyanine pigments; perylene pigments; indigo pigments such as indigo and thioindigo; It is formed by applying a dispersion liquid dispersed in polystyrene, polyvinyl acetate, acrylic resin or the like and drying or vacuum-depositing the pigment.

  The film thickness of the charge generation layer is preferably 5 μm or less, more preferably 0.01 to 3 μm.

  In the present invention, an intermediate layer having a barrier function or an adhesive function can be provided between the substrate and the photosensitive layer. The intermediate layer is formed by applying and drying a solution in which casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, polyurethane, gelatin and the like are dissolved.

  The film thickness of the intermediate layer is preferably 0.1 to 3.0 μm.

  In the present invention, a protective layer may be provided on the photosensitive layer.

  The material constituting the protective layer is polyester, polyarylate, polyethylene, polybrasene, polycarbonate, polyamide, polypropylene, polyimide, polyamideimide, polysulfone, polyacryl ether, polyacetal, phenol, acrylic, silicone, epoxy, urea, alkyd, butyral , Phenoxy, phosphazene, acrylic modified epoxy, acrylic modified urethane, and acrylic modified polyester resin.

  The thickness of the protective layer is preferably 0.2 to 10 μm.

  For each of the above layers, lubricants such as polytetrafluoroethylene, polyvinylidene fluoride, fluorine-based graft polymer, silicone-based graft polymer, fluorine-based block polymer, and silicone-based oil are used to improve cleaning properties and wear resistance. May be included.

  Further, for the purpose of improving the weather resistance, an additive such as an antioxidant may be added.

  The electrophotographic photosensitive member of the present invention can be used not only for electrophotographic copying machines but also widely for laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making electrophotographic applications.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

  As the substrate, an aluminum ED tube of JIS A3003 material having an outer diameter of 30 mm, an inner diameter of 28.5 mm, and a length of 260.5 mm was prepared.

  A liquid honing process was performed on the substrate using a liquid honing apparatus. Abrasive abrasive grains use spherical alumina beads with an average particle diameter of 30 μm (trade name: CB-A30S, manufactured by Showa Denko Co., Ltd.). went.

  The cylinder surface roughness after honing of the obtained substrate was Rmax 2.9 μm, Rz 2.0 μm, Ra 0.26 μm, Sm 35 μm.

  The substrate was cleaned with the apparatus shown in FIG. 2 according to the present invention under the following conditions. 3. In the detergent tank, 5 parts by weight of a surfactant (trade name: Van Rise D-20 Tokiwa Chemical Co., Ltd.) is dissolved in 95 parts by weight of water, the temperature is 40 ° C, and the prepared substrate is immersed for 1 minute. I let you. Next, after filling the rinsing tank with distilled water at room temperature and dipping for 30 seconds, the substrate was transferred to the 6. condensation tank. The detergent tank and rinse tank had a capacity of 5 liters and the entire length of the substrate was submerged. The dew condensation tank has a structure in which 2 liters of normal water is boiled in the lower part and water vapor is filled in the upper space, and the substrate is exposed to this water vapor space for 1 minute. Thereafter, when the substrate was carried out of the water vapor tank, an operation of blowing condensed water condensed on the substrate with an air knife was performed while simultaneously rotating the substrate.

  In addition, in order to make the effect of an experiment remarkable, the said washing | cleaning was implemented by the closed system which does not supply / drain water of a washing tank, a rinse tank, and a dew condensation tank.

  Next, 10 parts by weight of a polyamide resin (trade name: Amilan CM8000, manufactured by Toray), 30 parts by weight of a methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Teikoku Chemical Co., Ltd.), methanol 400 A paint dissolved in a mixed solvent of parts by weight and 200 parts by weight of n-butanol was dip-coated on a cleaned substrate and dried with hot air at 90 ° C. for 10 minutes to form an undercoat layer having a thickness of 0.65 μm.

  Next, 4 parts by weight of a titanyl phthalocyanine pigment having a diffraction peak 2θ ± 0.2 ° in the X-ray diffraction spectrum of CuKα having strong peaks at 9.0 °, 14.2 °, 23.9 °, and 27.1 °, polyvinyl butyral resin (trade name: BX-1 (Sekisui Chemical Co., Ltd.) 2 parts by weight and 60 parts by weight of cyclohexanone were dispersed in a sand mill using 1 mmφ glass beads for 4 hours, and then 100 parts by weight of ethyl acetate was added to prepare a dispersion for the charge generation layer. did.

  The dispersion was dip-coated on the intermediate layer and dried by heating at 95 ° C. for 10 minutes to form a charge generation layer. The film thickness of the charge generation layer was 0.3 μm.

  Next, 9 parts by weight of an amine compound having the following structural formula

下記構造式のアミン化合物1重量部

1 part by weight of amine compound of the following structural formula

ビスフェノールＺ型ポリカーボネート樹脂（商品名：ユーピロンＺ−２００，三菱ガス化学（株）製）を１０重量部、をモノクロロベンゼン７０重量部、ジクロロメタン３０重量部の混合溶媒に溶解した。この塗料を浸せき法で塗布し１２０℃で1時間乾燥し２５μmの電荷輸送層を形成した。

10 parts by weight of bisphenol Z-type polycarbonate resin (trade name: Iupilon Z-200, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was dissolved in a mixed solvent of 70 parts by weight of monochlorobenzene and 30 parts by weight of dichloromethane. This paint was applied by a dipping method and dried at 120 ° C. for 1 hour to form a 25 μm charge transport layer.

  In this way, 100 electrophotographic photoreceptors of the present invention were sequentially prepared, mounted on a printer LaserJet 4000 manufactured by Hewlett-Packard Co., and a halftone image was output to evaluate image defects. The results are shown in Table-1.

The image was determined based on the following criteria based on the number and size of defects on the halftone image corresponding to one drum rotation.
○: Image defect pear → non-defective product △: One or two image unevenness due to stains or spiders at the time of cleaning → Non-defective product at the lower limit of practical use ×: Three or more image unevenness due to smears or spiders at the time of cleaning → Practical use Impossible defective product

  An electrophotographic photoreceptor similar to that of Example 1 was prepared, except that the surface of the substrate was subjected to anodizing treatment instead of liquid honing, and Example 2 was obtained. As anodization, an anodized film having a thickness of 6 microns is obtained by using a standard method disclosed in JP-A-05-27466, 05-80566, 05-80568, 06-202363, etc. It was.

  The obtained electrophotographic photosensitive member was set as Example 2, and the same evaluation as in Example 1 was performed.

  In Example 1, an electrophotographic photosensitive member similar to that in Example 1 was prepared, except that the substrate was placed in a drying furnace at 80 ° C. for 1 minute and dried immediately after leaving the dew tank in place of the air knife. did. The evaluation method is the same as in Example 1, and is shown in Table-1.

(Comparative Example 1)
In Example 1, 100 electrophotographic photoreceptors were prepared continuously in the same manner as in Example 1 except that a conventional hot water washing tank was used instead of a dew condensation tank. In addition, it was set as the structure similar to an Example for both a washing tank and a rinse tank, and was set as the structure by which 5 liters of distilled water was filled in the hot water washing tank, and the full length of a base | substrate was buried in distilled water. The temperature of distilled water in the hot water bath was set to 80 ° C., and it was confirmed that the substrate was dried immediately after the hot water washes. In addition, in order to make the effect of the experiment remarkable as in Example 1, cleaning was performed in a closed system that does not supply and discharge water in each tank, and evaluation equivalent to that in Example 1 was performed. It was shown to.

  The same operation as in Example 1 was repeated to produce 500 electrophotographic photoreceptors. Among these, the material prepared from the 491th to the 500th was evaluated as Example 4.

(Comparative Example 2)
The same operation as in Comparative Example 1 was repeated to prepare 500 electrophotographic photosensitive members. Of these, 491 to 500 samples were evaluated as Comparative Example 2.

Diagram showing an example of conventional cleaning The figure which shows that the effect which does not exist is expressed

Claims (8)

  In an electrophotographic photosensitive member having a photosensitive layer on a substrate, the substrate is subjected to a water-based cleaning step, and then when the photosensitive layer is provided, the substrate is exposed to water vapor in the final cleaning step to cause dew condensation. An electrophotographic photosensitive member, wherein a photosensitive layer is provided after drying and drying by airflow or heating.   2. The electrophotographic photosensitive member according to claim 1, wherein the substrate is a conductive substrate made of aluminum or an alloy thereof.   3. The electrophotographic photosensitive member according to claim 1, wherein the substrate is subjected to a surface roughening treatment by a processing means for irradiating a polishing agent or abrasive grains typified by a honing treatment toward the substrate.   4. The electrophotographic photosensitive member according to claim 1, wherein the substrate is anodized.   In a method for producing an electrophotographic photosensitive member having a photosensitive layer on a substrate, the substrate is subjected to a water-based cleaning step, and then when the photosensitive layer is provided, the substrate is exposed to water vapor in the final cleaning step to cause condensation. A method for producing an electrophotographic photosensitive member, comprising providing a photosensitive layer after removing and drying the condensed water by airflow or heating.   2. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the substrate is a conductive substrate made of aluminum or an alloy thereof.   3. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the substrate is roughened by a processing means for irradiating a polishing agent or abrasive grains represented by a honing treatment toward the substrate. 4. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the substrate is anodized.

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