JP2008170819A - Method for removing photosensitive layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for removing a photosensitive layer where, when a photosensitive layer is removed from an electrophotographic photosensitive body, the removal is efficiently performed in a short time without giving damage to an electrically conductive substrate and without using a large quantity of solvent. <P>SOLUTION: The method for removing a photosensitive layer comprises: a solvent feeding stage where a photosensitive body is mounted on a photosensitive layer removing device including a solvent feeding means, a photosensitive layer removing drum, a scraping drum and a cleaning blade, and a solvent is fed from the solvent feeding means to the photosensitive layer; a photosensitive layer removing stage where the photosensitive layer removing drum is proximately arranged at the photosensitive body, while the photosensitive layer is transferred to the photosensitive layer removing drum, so as to be removed, and as the removal of the photosensitive layer is progressed, the spacing between the photosensitive body and the photosensitive layer removing drum is narrowed; and a separating stage where the photosensitive body and the photosensitive layer removing drum are separated after the removal of the photosensitive layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for removing a photosensitive layer.

  An image forming apparatus using an electrophotographic system (hereinafter simply referred to as “image forming apparatus”) is capable of printing a high-quality image on a recording medium with a simple operation, and thus is widely used as a copying machine, a printer, a facsimile machine, and the like. . The image forming apparatus includes, for example, an electrophotographic photosensitive member (hereinafter simply referred to as “photosensitive member” unless otherwise specified), a charging unit, an exposing unit, a developing unit, a transferring unit, a fixing unit, a cleaning unit, Neutralizing means. An electrostatic latent image and a toner image are formed on the surface of the photoreceptor. The charging means charges the surface of the photoreceptor to a predetermined polarity and potential. The exposure means exposes the charged surface of the photoconductor to form an electrostatic latent image corresponding to the image information. The developing means supplies toner to the electrostatic latent image to form a toner image. The transfer unit transfers the toner image onto the recording medium. The fixing unit fixes the toner image on the recording medium. The cleaning unit removes toner remaining on the surface of the photosensitive member at the time of transfer, paper dust attached to the surface of the photosensitive member, and the like. The neutralizing means neutralizes the surface charge of the photosensitive member and erases the electrostatic latent image. Through the processing by these means, an image according to the image information is formed on the recording medium.

  In the image forming apparatus, the photosensitive member includes a conductive substrate and a photosensitive layer provided on the surface of the conductive substrate and containing a photoconductive material. As the photoreceptor, an inorganic photoreceptor, an organic photoreceptor, and the like are known.

In inorganic photoreceptors, inorganic photoconductive materials such as amorphous selenium (a-Se), amorphous selenium arsenide (a-AsSe), zinc oxide, cadmium sulfide, and amorphous silicon (a-Si) are used. Examples of inorganic photoreceptors include selenium photoreceptors containing a-Se, a-AsSe, etc. in the photosensitive layer, and zinc oxide series or cadmium containing sensitizers such as zinc oxide or cadmium sulfide and a dye in the photosensitive layer. And an a-Si type photosensitive member containing a-Si in the photosensitive layer. Of these, selenium-based photoreceptors and cadmium-based photoreceptors have low heat resistance and storage stability, and are likely to cause thermal deterioration and deterioration over time. In addition, since selenium and cadmium are toxic to the human body and the environment, the selenium-based photoreceptor and cadmium-based photoreceptor need to be recovered after use and appropriately disposed. Zinc oxide photoreceptors are rarely used today because of their low sensitivity and durability. Although a-Si photoconductors have high safety, sensitivity and durability, plasma chemical vapor deposition (Plasma Chemical Vapor Deposition)
Therefore, it is difficult to form a photosensitive layer uniformly and image defects are likely to occur. In addition, the a-Si photoconductor has low productivity and high manufacturing cost.

  In an organic photoreceptor, an organic photoconductor is used as a photoconductive material. Although there is room for further improvement in terms of sensitivity, durability, storage stability, etc., an organic photoreceptor can form a photosensitive layer by simply applying a resin solution containing an organic photoconductor to a conductive substrate. Productivity is high and manufacturing costs are very low. In addition, it is low in toxicity and has a high degree of freedom in material design. Furthermore, at present, a function-separated organic type photoconductor having a photosensitive layer containing a charge generating material and a charge transporting material and having various performances remarkably improved has been developed and becomes the mainstream of the photoconductor. The function-separated organic photoconductor includes a stacked type in which a photosensitive layer is formed by laminating a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material, and a photosensitive layer comprising a charge generation material. There is a single layer type constituted by one layer containing a charge transport material. In the laminated type and single layer type functionally separated type photoreceptors, a photosensitive layer in which a charge generating substance and / or a charge transporting substance is dispersed in a binder resin is formed. Examples of charge generation materials include phthalocyanine pigments, squarylium dyes, azo pigments, perylene pigments, polycyclic quinone pigments, cyanine dyes, squaric acid dyes, pyrylium salt dyes, and the like, taking into account light resistance, charge generation ability, etc. The appropriate one is selected. Examples of the charge transport material include pyrazoline compounds, hydrazone compounds, triphenylamine compounds, stilbene compounds, pyrene derivatives having a condensed polycyclic hydrocarbon as a central mother nucleus, naphthalene derivatives, and terphenyl derivatives.

  For example, an organic photoconductor is formed by applying a coating solution containing a charge generating substance and / or a charge transporting substance, a binder resin, an organic solvent, etc. to the surface of the conductive substrate, and from the coating film formed on the surface of the conductive substrate to the organic solvent Can be produced by volatilizing and forming a photosensitive layer. Examples of the application method of the application liquid include a spray method, a ring coating method, a roll coating method, a blade method, and an immersion method. Volatilization of the organic solvent from the coating film is performed, for example, by heating the coating film to a temperature equal to or higher than the boiling point of the organic solvent. Organic photoconductors are partially defective when they are manufactured, and non-defective products are deteriorated due to repeated use over a long period of time to form an image, both of which require processing as waste. Become. However, the conductive substrate is relatively less damaged, deteriorated, deformed, etc. even after long-term use. In addition, the conductive substrate made of metal is expensive because it is accurately manufactured using a high-purity material. Reuse of is desired. In addition, even if there are many damages, deteriorations, deformations, etc. of the conductive substrate, the utility value is high as a raw material for the conductive substrate if it can be recovered at low cost.

  For this reason, various methods for removing the photosensitive layer and recovering the conductive substrate have been proposed. For example, a method for removing a photosensitive layer using a scraping member including a brush and a supporting member that supports the brush is proposed (see, for example, Patent Document 1). According to the technique of Patent Document 1, the photosensitive drum is supported in such a manner that its longitudinal direction is vertical, and the scraping member brush is in contact with the lower end portion of the photosensitive drum. The photosensitive layer is removed by rotating in the direction and pulling the conductive substrate upward. However, since the conductive substrate is mainly formed of a metal that is easily damaged by contact with other members, such as aluminum, in this method, the surface of the conductive substrate is damaged by rubbing the surface of the conductive substrate. , There is a drawback that it can not be reused. In addition, since a part of the removed photosensitive layer adheres to the brush or the support member and deteriorates the scraping member, the removal efficiency of the photosensitive layer decreases with time.

  Further, a method for removing a photosensitive layer is proposed which includes a step of immersing the end of the photosensitive drum in a solvent and a step of scraping off the photosensitive layer at the end of the photosensitive drum that swells by immersion in the solvent (for example, , See Patent Document 2). In the technique of Patent Document 2, a photosensitive layer removing device including a container and a blade is used. The container stores a solvent. The blade is provided in the horizontal direction so as not to contact the liquid level of the solvent stored in the container, and is supported by the container. The blade is formed with an opening that penetrates in the thickness direction (vertical direction) and has an inner diameter slightly smaller than the outer diameter of the photosensitive drum. The photosensitive layer is removed by inserting the photosensitive drum into the opening of the blade, immersing the end of the photosensitive drum in a solvent to swell the photosensitive layer, and then lifting the photosensitive drum unevenness upward. And the peripheral edge of the opening are in sliding contact. However, the technique of Patent Document 2 aims to remove a portion of the photosensitive layer unrelated to image formation formed on one end portion of the photosensitive drum in the manufacturing process of the photosensitive drum. If this technique is used for collecting the conductive substrate, a large amount of solvent and a long treatment time are required, and the surface of the conductive substrate may be damaged.

  Further, the photosensitive layer is swollen and removed by pressing the woven fabric impregnated with the solvent against the photoreceptor, and the photosensitive layer residue adhering to the woven fabric is scraped with a brush to repeatedly clean the woven fabric. A method for removing the photosensitive layer is proposed (see, for example, Patent Document 3). In the technique of Patent Document 3, it is necessary to use a halogen-based solvent as a solvent in order to efficiently remove the photosensitive layer residue adhering to the woven fabric with a brush. If other solvents are used from the viewpoint of the environment, the photosensitive layer residue of the woven fabric can be sufficiently removed, and the efficiency of removing the photosensitive layer from the photoreceptor is lowered.

JP-A-5-142789 JP-A-63-315174 JP 9-2111875 A

  An object of the present invention is to remove a photosensitive layer from an electrophotographic photosensitive member without damaging the conductive substrate, without using a large amount of solvent, and efficiently removing the photosensitive layer in a short time. It is to provide a removal method.

The present invention
A solvent supplying step of dissolving or swelling the photosensitive layer by bringing an organic solvent into contact with the photosensitive layer of the electrophotographic photoreceptor including the conductive substrate and the photosensitive layer provided on the surface of the conductive substrate;
When the photosensitive layer removing drum in a rotating state is brought close to the electrophotographic photosensitive member and the photosensitive layer in a dissolved or swollen state is transferred to the surface of the photosensitive layer removing drum to remove the photosensitive layer, the electron is removed as the photosensitive layer is removed. A photosensitive layer removing method comprising: a photosensitive layer removing step of narrowing a gap between the photographic photosensitive member and the photosensitive layer removing drum.

The method for removing the photosensitive layer of the present invention comprises:
After removing the photosensitive layer, the method includes a separation step of separating the photosensitive layer removing drum carrying the photosensitive layer on the surface thereof from the conductive substrate from which the photosensitive layer has been removed.

Furthermore, the method for removing the photosensitive layer of the present invention comprises:
The photosensitive layer on the surface of the photosensitive layer removing drum is removed by moving to the surface of the scraping drum.

Furthermore, the method for removing the photosensitive layer of the present invention comprises:
The organic solvent is volatilized from the photosensitive layer on the surface of the scraping drum, and then the blade is brought into contact with the surface of the scraping drum to remove the photosensitive layer.

Furthermore, the method for removing the photosensitive layer of the present invention comprises:
An organic solvent is sprayed from a nozzle to bring the organic solvent into contact with the photosensitive layer.

  According to the present invention, a method for removing a photosensitive layer including a solvent supplying step and a photosensitive layer removing step is proposed. In the solvent supply step, an organic solvent is brought into contact with the photosensitive layer of an electrophotographic photosensitive member (hereinafter simply referred to as “photosensitive member”) to dissolve or swell the photosensitive layer. In the photosensitive layer removing step, the photosensitive layer removing drum is rotated and brought close to the photosensitive member, and the photosensitive layer in a dissolved or swollen state is moved to the surface of the photosensitive layer removing drum to be removed. Narrow the gap with the layer removal drum. That is, the method of the present invention uses a photosensitive layer removing drum as a drum member to remove the photosensitive layer from the photosensitive member, and gradually brings the photosensitive layer removing drum closer to the photosensitive member as the photosensitive layer is removed. It is characterized by that. Therefore, in the present invention, the conventional scraping member is not brought into direct contact with the photosensitive member. According to the present invention having such a configuration, the photosensitive layer can be efficiently and reliably removed in a short time without damaging the conductive substrate and without using a large amount of solvent.

  Further, according to the present invention, it is preferable to add a separation step to the method of the present invention. The separation step is a step of separating the photosensitive layer removing drum carrying the photosensitive layer on the surface after the removal of the photosensitive layer is separated from the conductive substrate from which the photosensitive layer has been removed. At the end of the removal of the photosensitive layer, the conductive substrate and the photosensitive layer removal drum are in a very close state. If the photosensitive layer is recovered and removed from the photosensitive layer removal drum in this state, the conductive substrate may be damaged. is there. Therefore, if the photosensitive layer removing drum is separated from the conductive substrate and the photosensitive layer on the surface of the photosensitive layer removing drum is recovered and removed in this state, the conductive substrate can be reliably prevented from being damaged.

  Further, according to the present invention, since the photosensitive layer on the surface of the photosensitive layer removing drum is moved to the scraping drum surface and removed, almost no photosensitive layer residue remains on the photosensitive layer removing drum. Even if it repeats, it becomes difficult to reduce the removal efficiency of a photosensitive layer. Further, by using a scraping drum as a drum member instead of a conventional scraping member, the photosensitive layer removing drum itself is less damaged. Further, even if the surface of the photosensitive layer removing drum is slightly scratched due to contact with the scraping drum, the efficiency of removing the photosensitive layer is not reduced thereby.

Further, according to the present invention, the organic solvent is volatilized from the photosensitive layer on the surface of the scraping drum, and then the blade is brought into contact with the surface of the scraping drum to remove the photosensitive layer.
The photosensitive layer coating film transferred onto the scraping drum is dried and then peeled off with a blade, whereby the photosensitive layer residue can be easily removed from the scraping drum. Therefore, the residue of the photosensitive layer residue on the surface of the scraping drum is reduced, and even when the photosensitive layer removing operation is repeated, the removal efficiency of the photosensitive layer is hardly further lowered.

  Furthermore, according to the present invention, the photosensitive layer can be efficiently dissolved or swollen with a small amount of the organic solvent by spraying the organic solvent from the nozzle and bringing the organic solvent into contact with the photosensitive layer. The amount of organic solvent used can be reduced. Since disposal of the organic solvent after use is very expensive, reduction of the organic solvent is advantageous in terms of cost. Also, the load on the environment can be reduced.

  The photosensitive layer removing method of the present invention may include a solvent supplying step and a photosensitive layer removing step, and may include a separation step after the photosensitive layer removing step. The method of the present invention is performed using, for example, the photosensitive layer removing apparatus 1 shown in FIG. FIG. 1 is a cross-sectional view schematically showing the configuration of the photosensitive layer removing apparatus 1.

  Inside the photosensitive layer removing apparatus 1, there is provided an installation portion (not shown) for detachably mounting the photosensitive member 2 subjected to the removal processing of the photosensitive layer 3. The photosensitive member 2 attached to the installation site faces the solvent supply means 10 described later on one side in the horizontal direction and faces the photosensitive layer removing drum 11 described later on the other side, and its axis is parallel to the axis of the photosensitive layer removing drum 11. Will be placed at the position. The photosensitive member 2 is rotatably supported by a support unit (not shown) and is driven to rotate about an axis by a drive unit (not shown). The photosensitive member 2 is provided so as to be movable in the horizontal direction together with the support member by another driving means. Accordingly, the photosensitive member 2 can be brought close to or separated from the photosensitive layer removing drum 11, and the gap between the photosensitive member 2 and the photosensitive layer removing drum 11 can be adjusted as appropriate. When the photosensitive layer 3 of the photosensitive member 2 is removed by the photosensitive layer removing drum 11, the photosensitive member 2 is under rotation. At this time, the peripheral speed of the photoreceptor 2 is preferably 1 to 600 m / min. An appropriate peripheral speed may be selected from the peripheral speed range according to the material of the photosensitive layer 3, the type of the solvent 14 supplied from the solvent supply means 10, and the like. When the peripheral speed is low, the photosensitive layer once in a dissolved or swollen state is dried, the removal of the photosensitive layer 3 becomes insufficient, and it is necessary to use an extra solvent 14. On the other hand, if the peripheral speed is too high, the photosensitive layer, the solvent 14 and the like may be scattered by centrifugal force.

  The photoreceptor 2 is preferably an organic photoreceptor having a drum shape such as a cylindrical shape or a columnar shape. The organic photoreceptor is not particularly limited as long as it includes the conductive substrate 4 and the photosensitive layer 3 provided on the surface of the conductive substrate 4 and containing the organic photoconductor. Specifically, the conductive substrate 4 and the photosensitive layer 3 are as follows.

(Conductive substrate 4)
Examples of the conductive substrate 4 include those made of metal materials such as aluminum, aluminum alloy, copper, zinc, stainless steel, and titanium, synthetic resins such as polyethylene terephthalate, polyester, polyoxymethylene, and polystyrene, hard paper, and glass. And a non-conductive material provided with a conductive layer on the surface of the substrate. The conductive layer can be formed by, for example, laminating a metal foil, depositing a conductive material, applying a conductive composition containing a resin and a conductive material, and the like. Here, the conductive material is metal, carbon, tin oxide, indium oxide, or the like. If necessary, the surface of the conductive substrate 4 may be subjected to irregular reflection processing within a range that does not affect the image quality of an image formed when used as the photoreceptor 2. In the electrophotographic process using a laser as an exposure light source, the wavelengths of the incident laser light are uniform, so that the incident laser light and the light reflected in the photoreceptor 2 cause interference, and interference fringes due to this interference appear on the image. It may appear and image defects may occur. By subjecting the surface of the conductive substrate 4 to irregular reflection processing, it is possible to prevent image defects due to the interference of laser light having the same wavelength. Specific examples of the irregular reflection treatment include, for example, an anodized film treatment, surface treatment with chemicals, hot water, coloring treatment, roughening treatment, and the like. The shape of the conductive substrate 4 is preferably cylindrical or columnar.

(Photosensitive layer 3)
The photosensitive layer 3 may be either a laminated type photosensitive layer or a single layer type photosensitive layer. The laminated photosensitive layer is a laminate of a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. In the laminated photosensitive layer, the charge generation layer does not need to be a single layer, and two or more layers having different configurations may be laminated in order to develop required characteristics. The same applies to the charge transport layer. The single-layer type photosensitive layer is a layer containing a charge generation material and a charge transport material which are organic photoconductors at the same time.

(Charge generation layer)
The charge generation layer is a layer containing a charge generation material. The charge generation layer contains a binder resin, various additives, and the like as necessary along with the charge generation material. The charge generation layer preferably includes a charge generation material and a binder resin. The charge generation layer is obtained, for example, by applying a coating solution for forming a charge generation layer to the surface of the conductive substrate 4, the undercoat layer or the charge transport layer, preferably the surface of the conductive substrate 4 or the undercoat layer. Can be naturally dried or heated to volatilize or evaporate the solvent in the coating. The coating solution for forming a charge generation layer can be prepared by dissolving or dispersing a charge generation material and, if necessary, a binder resin and various additives in a solvent. Prior to dissolving or dispersing the charge generating material in the solvent, the charge generating material may be pulverized. The pulverization process is performed using, for example, a pulverizer. Examples of the pulverizer include a ball mill, a sand mill, an attritor, a vibration mill, and an ultrasonic disperser. In addition, when pulverizing the charge generating substance and dissolving or dispersing it in a solvent, it is necessary to select appropriate conditions so that impurities derived from the container used, the pulverizer and the members constituting the disperser do not occur. Good. Examples of the coating method for the charge generation layer forming coating solution include a spray method, a ring coating method, a roll coating method, a blade method, and a dipping method.

  The film thickness of the charge generation layer is preferably 0.05 to 5 μm, more preferably 0.1 to 1 μm. If the thickness of the charge generation layer is less than 0.05 μm, the light absorption efficiency and thus the sensitivity of the photoreceptor 2 may be reduced. When the film thickness of the charge generation layer exceeds 5 μm, the charge transfer inside the charge generation layer becomes a rate-determining step in the process of erasing the charge on the surface of the photoreceptor 2 and the sensitivity may be lowered.

  The charge generation material is an organic compound or an inorganic compound that generates a charge by absorbing light. As the charge generation material, those commonly used in this field can be used, for example, azo pigments such as monoazo pigments, bisazo pigments and trisazo pigments, indigo pigments such as indigo and thioindigo, and perylenes such as peryleneimide and perylene anhydride. Pigments, polycyclic quinone pigments such as anthraquinone and pyrenequinone, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, triphenylmethane pigments such as methyl violet, crystal violet, knight blue and victoria blue, erythrosine, rhodamine B, Rhodamine 3R, acridine dyes such as acridine orange, frappeosin, thiazine dyes such as methylene blue and methylene green, oxazine dyes such as capri blue and meldra blue, squary Dyes, pyrylium salts, thiopyrylium salts, thioindigo dyes, bisbenzimidazole dyes, quinacridone dyes, quinoline dyes, lake dyes, azo lake dyes, dioxazine dyes, azurenium dyes, triarylmethane dyes, xanthenes Examples thereof include various organic pigments such as pigments and cyanine pigments, dyes, amorphous silicon, amorphous selenium, tellurium, selenium-tellurium alloys, cadmium sulfide, antimony sulfide, zinc oxide, and zinc sulfide. One type of charge generating material can be used alone, or two or more types can be used in combination.

  Any of those commonly used in this field can be used as the binder resin, for example, thermoplastic resins such as polyester, polystyrene, acrylic resin, methacrylic resin, polycarbonate, polyarylate, polyurethane, phenol resin, alkyd resin, melamine resin, Examples thereof include thermosetting resins such as epoxy resins, silicone resins, phenoxy resins, polyvinyl butyral, and polyvinyl formal, and copolymers containing two or more of repeating units constituting these resins. Although it does not restrict | limit especially as a copolymer, For example, insulating resin, such as a vinyl chloride-vinyl acetate copolymer, a vinyl chloride-vinyl acetate-maleic anhydride copolymer, an acrylonitrile-styrene copolymer, is preferable. Binder resin can be used individually by 1 type, or can use 2 or more types together. The mixing ratio of the charge generation material and the binder resin is not particularly limited, but the charge generation material is mixed so that the content of the charge generation layer is 10 to 99% by weight with respect to the total amount of the charge generation material and the binder resin. Is preferred. If the content of the charge generating material is less than 10% by weight, the sensitivity of the photoreceptor 2 may be lowered. When the content of the charge generation material exceeds 99% by weight, the mechanical strength of the charge generation layer is lowered, the dispersibility of the charge generation material is lowered, and coarse particles are increased. As a result, surface charges other than those that should be erased by exposure are reduced, and there is a risk of image fogging, particularly image fogging called black spots, where toner adheres to a white background and fine black spots are formed. is there.

  Examples of various additives include hole transport materials, electron transport materials, antioxidants, dispersion stabilizers, and sensitizers. By adding these, the potential characteristics are improved and the stability as a coating solution is improved. Further, fatigue deterioration when the photoreceptor 2 is repeatedly used can be reduced, and durability can be improved.

  Examples of the solvent include halogenated hydrocarbons such as 1,3-dichloropropane and trichloroethane, ketones such as isophorone, methyl ethyl ketone, acetophenone, cyclohexanone and isophorone, and esters such as ethyl acetate, methyl benzoate and n-butyl acetate. , Tetrahydrofuran, 1,4-dioxane, dibenzyl ether, ethers such as 1,2-dimethoxyethane, aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, tetralin, diphenylmethane, dimethoxybenzene, dichlorobenzene, Sulfur-containing solvents such as diphenyl sulfide, fluorine-based solvents such as hexafluoroisopropanol, glyme solvents such as ethylene glycol monobutyl ether and diethylene glycol monobutyl ether, N N- dimethylformamide, N, N- aprotic polar solvents such as dimethylacetamide, etc. These mixed solvent of two or more thereof.

(Charge transport layer)
The charge transport layer is a layer containing a charge transport material. Furthermore, the charge transport layer may contain a binder resin, various additives, and the like as necessary. The charge transport layer preferably includes a charge transport material and a binder resin. The charge transport layer is formed by, for example, applying a coating solution for forming a charge transport layer to the surface of the conductive substrate 4, the undercoat layer or the charge generation layer, preferably the surface of the charge generation layer, and naturally drying the resulting coating film. Or it can form by evaporating or evaporating the solvent in a coating film by heating. The coating solution for forming a charge transport layer can be prepared by dissolving or dispersing a charge transport material and, if necessary, a binder resin and various additives in a solvent. Examples of the coating method of the charge transport layer forming coating solution include a spray method, a ring coating method, a roll coating method, a blade method, and a dipping method.

The charge transport layer preferably has a mobility of 1.0 × 10 ⁻⁶ cm ² / Vs or more at an environmental temperature of 5 ° C. and an electric field strength of 2.5 × 10 ⁵ V / cm. Thereby, the responsiveness of the photoreceptor 2 required for the current image formation can be sufficiently ensured. The film thickness of the charge transport layer is preferably 5 to 50 μm, more preferably 10 to 40 μm. If the thickness of the charge transport layer is less than 5 μm, the charge holding ability on the surface of the photoreceptor 2 may be lowered. If the thickness of the charge transport layer exceeds 50 μm, the resolution of the photoreceptor 2 may be reduced.

  The charge transport material is an organic compound or an inorganic compound having the ability to accept and transport charges generated from the charge generation material. Examples of the charge transport material include a hole transport material and an electron transport material. As the hole transport material, those commonly used in this field can be used. For example, carbazole derivatives, pyrene derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives , Bisimidazolidine derivatives, styryl compounds, hydrazone compounds, polycyclic aromatic compounds, indole derivatives, pyrazoline derivatives, oxazolone derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamines Derivatives, triarylmethane derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine derivatives, these compounds are Such polymer bonded to the chain. Examples of the polymer include poly-N-vinylcarbazole, poly-1-vinylpyrene, ethylcarbazole-formaldehyde resin, triphenylmethane polymer, poly-9-vinylanthracene, and polysilane. As the electron transporting material, those commonly used in this field can be used. For example, benzoquinone derivatives, tetracyanoethylene derivatives, tetracyanoquinodimethane derivatives, fluorenone derivatives, xanthone derivatives, phenanthraquinone derivatives, phthalic anhydride derivatives, Inorganic materials such as organic compounds such as diphenoquinone derivatives, amorphous silicon, amorphous selenium, tellurium, selenium-tellurium alloys, cadmium sulfide, antimony sulfide, zinc oxide, and zinc sulfide can be given. The charge transport materials can be used alone or in combination of two or more.

As the binder resin, those having excellent compatibility with the charge transporting material are preferable. For example, vinyl polymer resins such as polymethyl methacrylate, polystyrene, and polyvinyl chloride and copolymer resins thereof, polycarbonate, polyester, polyester carbonate, Thermoplastic resins such as polysulfone, polyarylate, polyphenylene oxide, polyamide, methacrylic resin, acrylic resin, polyether, and polyacrylamide, thermosetting resins such as phenoxy resin, epoxy resin, silicone resin, polyurethane, and phenol resin, and these thermoplastics Examples thereof include a thermosetting resin obtained by partially crosslinking a resin and a thermosetting resin. Among these, thermoplastic resins such as polystyrene, polycarbonate, polyarylate, and polyphenylene oxide have a volume resistance of 10 ¹³ Ω or more and are excellent in electrical insulation, and are also excellent in film formability and electrical characteristics. preferable. Binder resin can be used alone or in combination of two or more. The use ratio of the charge transport material and the binder resin is not particularly limited, but preferably 120 to 300 parts by weight of the binder resin is used with respect to 100 parts by weight of the charge transport material. When the amount of the binder resin used is less than 120 parts, the content of the binder resin in the charge transport layer is lowered, the printing durability of the charge transport layer is lowered, and the wear amount is increased. When the amount of the binder resin used exceeds 300 parts by weight, the content of the binder resin in the charge transport layer becomes high, whereby sufficient responsiveness cannot be obtained with the charge transport ability of the current charge transport material.

  Examples of the various additives include plasticizers, surface modifiers, light stabilizers, fillers, and the like. The plasticizer and the surface modifier improve, for example, the film formability, flexibility, and surface smoothness of the charge transport layer. Examples of the plasticizer include biphenyl, biphenyl chloride, benzophenone, o-terphenyl, dibasic acid ester, fatty acid ester, phosphate ester, phthalate ester, various fluorohydrocarbons, chlorinated paraffin, and epoxy type plasticizer. Can be mentioned. Examples of the surface modifier include silicone oil and fluororesin. The light stabilizer also has an effect as an antioxidant. For example, deterioration of the photosensitive layer 3 due to adhesion of active substances such as ozone and NOx generated when the photosensitive member 2 is charged to the surface of the photosensitive layer 3 is reduced. Further, durability against repeated use of the photoreceptor 2 can be improved. Moreover, the stability of the coating liquid for forming the charge transport layer is increased, and the life of the liquid is extended. In addition, the generation of impurities due to decomposition of the contained components during storage of the coating solution is suppressed. This impurity adversely affects the durability of the photoreceptor 2. Therefore, if a coating solution containing a light stabilizer is used, the photoconductor 2 having high durability is always obtained. As the light stabilizer, for example, hindered phenol derivatives and hindered amine derivatives are preferable. A light stabilizer can be used individually by 1 type, or can use 2 or more types together. The amount of the light stabilizer used is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the charge transport material. If the amount of the light stabilizer used is less than 0.1 parts by weight, the effect of improving the stability of the charge transport layer forming coating solution and the durability of the photoreceptor 2 may be insufficient. Further, if the amount of the light stabilizer used exceeds 10 parts by weight, the electrical characteristics of the photoreceptor 2 may be adversely affected. The filler, for example, enhances the mechanical strength of the charge transport layer and improves the electrical properties. Examples of the filler include fine particles of inorganic compounds and fine particles of organic compounds.

  Examples of the solvent include halogenated hydrocarbons such as 1,3-dichloropropane and trichloroethane, ketones such as isophorone, methyl ethyl ketone, acetophenone, cyclohexanone and isophorone, and esters such as ethyl acetate, methyl benzoate and N-butyl acetate. , Tetrahydrofuran, 1,4-dioxane, dibenzyl ether, ethers such as 1,2-dimethoxyethane, aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, tetralin, diphenylmethane, dimethoxybenzene, dichlorobenzene, Sulfur-containing solvents such as diphenyl sulfide, fluorine-based solvents such as hexafluoroisopropanol, glyme solvents such as ethylene glycol monobutyl ether and diethylene glycol monobutyl ether, N N- dimethylformamide, N, N- aprotic polar solvents such as dimethylacetamide, etc. These mixed solvent of two or more thereof. Among these solvents, those that do not dissolve or swell the layer immediately below the charge transport layer are used. Furthermore, if necessary, a solvent that is difficult to dissolve the charge transporting material or the like may be used in combination. Examples of such a solvent include alcohols, acetonitrile, methyl ethyl ketone, and the like.

  The single-layer type photosensitive layer can be formed in the same manner as the charge transport layer except that a charge generation material is used together with the charge transport material. For example, a charge generating material, a hole transport material or electron transport material that is a charge transport material, and a binder resin are dissolved or dispersed in a solvent composed of the above-mentioned appropriate solvent to form a single layer type photosensitive layer forming coating solution. A single-layer type photosensitive layer is formed by preparing and applying the coating solution for forming the photosensitive layer 3 to the surface of the conductive substrate 4 or the undercoat layer. The film thickness of the single-layer type photosensitive layer is preferably 5 to 100 μm, more preferably 10 to 50 μm. When the thickness of the photosensitive layer 3 is less than 5 μm, the charge holding ability on the surface of the photoreceptor 2 is lowered. When the film thickness of the photosensitive layer 3 exceeds 100 μm, the productivity is lowered.

(Undercoat layer)
An undercoat layer (not shown) may be provided between the photosensitive layer 3 and the conductive substrate 4. As a result, it is possible to prevent the injection of electric charges from the conductive substrate 4 to the photosensitive layer 3, and hence the deterioration of the charging property of the photosensitive member 2. Since the photoreceptor 2 on which the undercoat layer is formed suppresses the decrease in surface charge other than the portion to be erased by exposure, it is possible to prevent the occurrence of image defects such as fogging. Also, by providing the undercoat layer, defects such as fine irregularities on the surface of the conductive substrate 4 are covered with the undercoat layer, so that the surface for forming the photosensitive layer 3 becomes uniform, and the photosensitive layer 3 has a uniform surface. The film formability is improved. Further, by providing the undercoat layer, the adhesion of the photosensitive layer 3 to the conductive substrate 4 can be improved, and the peeling of the photosensitive layer 3 from the conductive substrate 4 can be prevented.

  The undercoat layer includes a resin material and optionally metal oxide particles. The undercoat layer is formed by, for example, applying a coating solution for forming an undercoat layer to the surface of the conductive substrate 4 and the like, and naturally drying or heating and drying the resulting undercoat layer coating film. Can be formed by volatilization or evaporation. The coating solution for forming the undercoat layer can be prepared by dissolving or dispersing the resin material and, if necessary, the metal oxide particles in a solvent. Examples of the coating method for the coating solution for forming the undercoat layer include a spray method, a ring coating method, a roll coating method, a blade method, and a dipping method. When forming the photoreceptor 2 including the undercoat layer, the charge generation layer or the like may be formed after the undercoat layer coating film is dried to form the undercoat layer. You may dry both coating films, after forming the coating film for charge generation layers in the upper layer of the coating film for undercoat layers, without drying a film | membrane. The undercoat layer may be an alumite layer. The thickness of the undercoat layer is preferably 0.01 to 20 μm, more preferably 0.1 to 10 μm. If the thickness of the undercoat layer is less than 0.01 μm, it may not function as an undercoat layer substantially, and it may be difficult to obtain a uniform surface by covering defects of the conductive substrate 4. In addition, since charge injection from the conductive substrate 4 to the photosensitive layer 3 cannot be prevented, the chargeability of the photosensitive layer 3 may be reduced. If the thickness of the undercoat layer exceeds 20 μm, it is difficult to form the undercoat layer uniformly, and the sensitivity of the photoreceptor 2 may be lowered.

  Examples of the resin material include polyethylene, polypropylene, polystyrene, acrylic resin, vinyl chloride resin, vinyl acetate resin, polyester, polycarbonate, polyester carbonate, polysulfone, polyamide, polyarylate, and other thermoplastic resins, polyurethane, epoxy resin, and melamine resin. , Thermosetting resins such as phenoxy resin, silicone resin, polyvinyl butyral, copolymers containing two or more of these thermoplastic resins and repeating units constituting the thermosetting resin, casein, gelatin, polyvinyl alcohol, Examples include ethyl cellulose. The resin material can be used alone or in combination of two or more.

  By adding metal oxide particles, for example, the volume resistance value of the undercoat layer is adjusted, and injection of charges from the conductive substrate 4 to the photosensitive layer 3 is further suppressed. In addition, the electrical characteristics of the photoreceptor 2 can be maintained even when there are changes in temperature, humidity, and the like. Examples of the metal oxide particles include particles of titanium oxide, aluminum oxide, aluminum hydroxide, tin oxide, and the like. When containing metal oxide particles in the undercoat layer, for example, a resin solution is prepared by dissolving the resin material in a solvent, and the metal oxide particles are dispersed in this resin solution to prepare a coating solution for forming the undercoat layer. It is preferable to do this. In order to disperse the metal oxide particles in the resin solution, a general disperser such as a ball mill, a sand mill, an attritor, a vibration mill, or an ultrasonic disperser is used. When using metal oxide particles, the amount used is preferably 10 to 99% by weight, more preferably 30 to 95% by weight of the total amount of the resin material and the metal oxide particles.

  As the solvent, in addition to the solvent used for forming the charge generation layer and the charge transport layer, water, alcohols such as methanol, ethanol and butanol, and glyme solvents such as ethylene glycol monobutyl ether and diethylene glycol monobutyl ether can be used. . A solvent can be used individually by 1 type or can use 2 or more types together. The amount of the solvent used in the coating solution for forming the undercoat layer is preferably 1 to 40% by weight, more preferably 2 to 30% by weight, based on the total amount of the coating solution for forming the undercoat layer.

(Protective layer)
A protective layer (not shown) may be provided on the surface of the photosensitive layer 3. By providing the protective layer, the printing durability and abrasion resistance of the photosensitive layer 3 can be improved, and ozone, nitrogen oxides and the like generated when the surface of the photosensitive member 2 is charged by corona discharge are formed on the photosensitive layer 3. On the other hand, it can prevent chemical adverse effects. Furthermore, in order to suppress unevenness of the conductivity of the conductive substrate 4, the conductive photosensitive layer 3 formed of carbon paste, silver paste or the like may be provided on the surface of the conductive substrate 4.

  The protective layer includes, for example, a resin material and, if necessary, a filler, a charge transport material, an additive, and the like. The protective layer can be formed, for example, by applying a coating solution for forming a protective layer to the surface of the photosensitive layer 3 and volatilizing or evaporating the solvent contained in the coating film by natural drying or heat drying. The coating liquid for forming the protective layer can be prepared, for example, by dissolving or dispersing a resin material and, if necessary, a filler, a charge transport material, an additive and the like in a solvent. Examples of the method for applying the coating liquid for forming the protective layer include a spray method, a ring coating method, a roll coating method, a blade method, and an immersion method. The thickness of the protective layer is preferably 0.5 to 5 μm, more preferably 1 to 3 μm. When the thickness of the protective layer is less than 0.5 μm, the protective layer easily peels off from the interface with the lower layer when subjected to an external force due to contact with the charging member or the cleaning blade member. This is because when the thickness of the protective layer is less than 0.5 μm, when the external force is applied, the protective layer itself is not resisted and the force is always applied to the interface with the lower layer, and if it is applied for a long time, the load is applied. This is thought to be because the interface is likely to be displaced by force. If the thickness of the protective layer is less than 0.5 μm, the protective layer may be lost due to wear before the photoreceptor 2 reaches the end of its useful life. When the thickness of the protective layer exceeds 5 μm, carriers are diffused in the process of moving in the protective layer, so that character thickening is likely to occur, and there is a possibility that the sensitivity of the photosensitive member 2 is lowered and the residual potential is increased due to repetition. .

  Examples of the resin material include acrylonitrile-butadiene-styrene resin, acrylonitrile-chlorinated polyethylene-styrene resin, acrylonitrile-styrene resin, butadiene-styrene copolymer, olefin-vinyl monomer copolymer, chlorinated polyether, and allyl resin. , Polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, polybutylene terephthalate, polyethylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, Thermoplastic resins such as polyvinyl chloride and polyvinylidene chloride, polyurethane, epoxy resin, phenol Resin, fluorine resin, silicone resin, crosslinking organopolysiloxane such as a thermosetting resin, and mixtures of two or more thereof and the like. Of these, the wear resistance of the protective layer can be improved by adding an appropriate amount of fluorine resin, silicone resin or the like to other resins. As the fluororesin, polytetrafluoroethylene is preferable.

  The filler increases, for example, the wear resistance of the protective layer, thereby extending the useful life of the photoreceptor 2. As the filler, inorganic particles and organic particles having relatively high hardness are used. The volume average particle diameter of the inorganic particles and the organic particles is preferably 0.02 to 3 μm, more preferably 0.05 to 1 μm. When the average particle size is less than 0.02 μm, the effect of improving the wear resistance is low, and the service life of the photoreceptor 2 cannot be extended. If the average particle size exceeds 3 μm, the signal light from the exposure means is scattered by the protective layer, the resolution is lowered, and the image may not be accurately reproduced. Specific examples of the inorganic compound constituting the inorganic particles include, for example, titanium oxide, tin oxide, zinc oxide, zirconium oxide, indium oxide, calcium oxide, indium-tin oxide (ITO), silica, colloidal silica, alumina and the like. Examples thereof include oxides, nitrides such as silicon nitride, sulfates such as barium sulfate, and carbon black. Specific examples of the organic compound constituting the organic particles include, for example, a fluororesin, a polysiloxane resin, and a polymer charge transport material. A filler can be used individually by 1 type, or can use 2 or more types together. The filler may be subjected to a surface treatment for the purpose of improving dispersibility in the resin material, modifying the surface property of the filler, and the like. For the surface treatment, a surface treatment agent such as a silane coupling agent, a fluorine-based silane coupling agent, or a higher fatty acid is used. Further, when the filler is organic particles, another resin material may be copolymerized on the surface. By treatment with the surface treatment agent and copolymerization of the resin material, for example, water repellency is imparted to the surface of the filler. Moreover, you may surface-treat with inorganic substances, such as an alumina, a zirconia, a tin oxide, and a silica. The content of the filler in the protective layer is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, based on the total amount of the protective layer. If it is less than 5% by weight, the effect of improving the wear resistance is insufficient, and if it exceeds 50% by weight, the transparency of the protective layer is impaired and the sensitivity is lowered.

  The charge transport material imparts a charge transport function to the protective layer, and is used to further improve the hole or electron transport efficiency in the charge transport layer of the laminated photosensitive layer and the photosensitive layer 3 of the single-layer photosensitive layer. As the charge transport material, any of those mentioned in the description of the charge transport layer can be used. Further, in order to impart a charge transport function to the protective layer, the protective layer may be formed using a charge transporting binder resin. Thereby, a protective layer having excellent durability and electrical characteristics can be obtained. The charge transporting binder resin can be obtained by crosslinking a charge transporting substance to the crosslinkable binder resin. Examples of the crosslinkable binder resin include crosslinkable organopolysiloxane. The charge transport material used here is a compound or polymer containing at least one crosslinkable group capable of binding to the crosslinkable group of the crosslinkable binder resin and one structural unit having charge transportability per molecule.

  Examples of the additive include a charge improver, a plasticizer, and a leveling agent. Examples of the chargeability improver include phenol compounds, hydroquinone compounds, hindered phenol compounds, hindered amine compounds, and compounds containing hindered amines and hindered phenols. As a plasticizer, what is used for a general resin material can be used, For example, a dibutyl phthalate, a dioctyl phthalate, etc. are mentioned. The amount of the plasticizer used is preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the resin material. Examples of the leveling agent include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers having a perfluoroalkyl group in the side chain, oligomers, and the like. The amount of the leveling agent used is preferably 0.001 to 1 part by weight with respect to 100 parts by weight of the resin material.

  Examples of the solvent include lower alcohols such as methanol, ethanol and butanol, glymes such as ethylene glycol monobutyl ether and diethylene glycol monobutyl ether, ethers such as tetrahydrofuran, 1,4-dioxane and diethyl ether, hexane, heptane and the like. Aliphatic hydrocarbons, aromatic hydrocarbons such as benzene and pyridine, water, a mixed solvent of two or more of these, and the like can be used. Among these, water, alcohols, glymes and the like are preferable. In addition, when the resin material which comprises the lower layer of a protective layer is soluble in the solvent contained in the coating liquid for protective layer formation, it is preferable to apply | coat the coating liquid for protective layer formation to a lower layer surface by the roll coating method.

  In order to reduce the surface energy of the protective layer, a material having a silicone structure, a perfluoroalkyl structure, a long-chain alkyl structure, or the like may be bonded to the surface of the protective layer by a crosslinking reaction or the like.

  The photoconductor 2 that is the target of the removal method of the present invention is not limited to the layer configuration described above, and can take various layer configurations.

  Returning now to FIG. The photosensitive layer removing apparatus 1 is provided with an installation position of the photosensitive member 2 therein, and includes a solvent supply unit 10, a photosensitive layer removing drum 11, a scraping drum 12, and a cleaning blade 13.

  The solvent supply means 10 is provided so as to face the photoreceptor 2 mounted at the installation position, supplies the solvent 14 toward the surface of the photoreceptor 2, and the photosensitive layer 3 and the solvent 14 (not shown) on the surface of the photoreceptor 2 are provided. Is contacted to dissolve or swell the photosensitive layer 3. The surface of the photosensitive layer 3 in a dissolved or swollen state exhibits adhesiveness, and the adhesion between the photosensitive layer 3 and the conductive substrate 4 is weakened at the interface between the photosensitive layer 3 and the conductive substrate 4. Accordingly, the surface of the photosensitive layer 3 adheres to the surface of the photosensitive layer removing drum 11, peels off from the conductive substrate 4 as the photosensitive layer removing drum 11 rotates, is wound around the photosensitive layer removing drum 11, and is exposed to the photosensitive layer removing drum 11. Transition to the surface. The supply speed of the solvent 14 to the photoreceptor 2 by the solvent supply means 10 is appropriately selected according to the material of the photosensitive layer 3, the kind of the solvent 14, and the like, but is preferably 1 to 10 ml / min. For the solvent supply means 10, for example, a liquid jet nozzle is used. Examples of the solvent 14 include aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, tetralin, diphenylmethane, dimethoxybenzene, and dichlorobenzene, halogenated hydrocarbons such as dichloromethane and dichloroethane, tetrahydrofuran, dioxane, and dibenzyl. Ethers such as ether and dimethoxymethyl ether, ketones such as cyclohexanone, acetophenone and isophorone, esters such as methyl benzoate and ethyl acetate, sulfur-containing solvents such as diphenyl sulfide, fluorine-based solvents such as hexafluoroisopropanol, N , N-dimethylformamide and other aprotic polar solvents, methanol, ethanol, butanol and other lower alcohols, ethylene glycol monobutyl ether, diethylene Glyme solvents such as glycol monobutyl ether, and combinations of two or more mixed solvents can be used. In the case where the photosensitive layer 3 is a multilayer photosensitive layer, the solvent suitable for dissolution and swelling may differ depending on each layer constituting the multilayer photosensitive layer, and therefore the solvent 14 used depending on the progress of the removal of the photosensitive layer 3. May be changed. At this time, the solvent 14 supplied to the photosensitive layer 3 may be changed by using one solvent supply means 10 and changing the solvent 14 supplied to the solvent supply means 10. Further, a plurality of solvent supply means 10 may be provided, and a different solvent 14 may be supplied for each solvent supply means 10.

  The photosensitive layer removing drum 11 is a roller-like member provided so as to be rotatable around an axis by a driving unit (not shown). The peripheral speed of the photosensitive layer removing drum 11 is preferably 1 to 600 m / min. From the above range, an appropriate peripheral depending on the material of the photosensitive layer 3 (particularly the type of binder resin), the type of the solvent 14, the supply amount of the solvent 14 to the surface of the photosensitive member 2, the peripheral speed of the photosensitive member 2, and the like. Just select the speed. When the peripheral speed is low, the solvent 14 that dissolves or swells the photosensitive layer 3 is dried and the adhesiveness of the surface of the photosensitive layer 3 is lowered. As a result, the transfer of the photosensitive layer 3 from the photosensitive member 2 to the photosensitive layer removing drum 11 may be insufficient. On the other hand, if the peripheral speed is too high, the centrifugal force increases, and the solvent 14 and a part of the photosensitive layer 3 may be scattered. For the photosensitive layer removing drum 4, for example, a cored bar made of a metal material such as stainless steel, iron, or aluminum is used, but a cored bar provided with an elastic layer is preferable. The elastic layer includes an elastic material. Examples of the elastic material include rubbers such as silicone rubber, organic polysulfide rubber, nitrile / butadiene rubber, nitrosulfonated polyethylene and styrene / butadiene rubber, and resins having elasticity such as silicone resin and fluororesin. What provided the coating layer containing a fluororesin etc. on the surface of the elastic layer containing rubbers may be used. In consideration of the removal efficiency of the photosensitive layer 3 and the like, it is preferable to use a photosensitive layer removing drum 11 having an outer diameter larger than that of the photoreceptor 2. The photosensitive layer removing drum 11 removes the photosensitive layer 3 from the photosensitive member 2 by adhering the photosensitive layer 3 on the surface of the photosensitive member 2 dissolved or swollen by the solvent 14 to the surface of the photosensitive member 2 while rotating. .

  The scraping drum 12 is in contact with the photosensitive layer removing drum 11 in the rotational direction of the photosensitive layer removing drum 11 and on the downstream side of the position where the photosensitive member 2 and the photosensitive layer removing drum 11 are opposed to or in contact with the photosensitive layer removing drum 11. It is a roller-like member provided so that the axis and the axis of the photosensitive layer removing drum 11 are parallel to each other. The scraping drum 12 is rotatably provided by a support member (not shown) and is driven to rotate by a driving means (not shown). The scraping drum 12 is rotated at a predetermined peripheral speed by a driving device in a state where the scraping drums 12 are close to each other. The peripheral speed of the scraping drum 12 is preferably 1 to 600 m / min. From the above range, the material of the photosensitive layer 3 (particularly the type of binder resin), the type of the solvent 14, the elapsed time after the solvent 14 is supplied to the photosensitive layer 3, the contact of the scraping drum 12 against the photosensitive layer removing drum 11. An appropriate peripheral speed may be selected according to the contact pressure or the like. When the peripheral speed is low, the solvent evaporates from the photosensitive layer residue 3a carried on the photosensitive layer removing drum 11, and the adhesive force of the photosensitive layer residue 3a to the photosensitive layer removing drum 11 increases. For this reason, the transfer of the photosensitive layer residue 3a from the photosensitive layer removing drum 11 to the scraping drum 12 becomes insufficient. Further, even if the photosensitive layer residue 3a moves to the surface of the scraping drum 12, the removal of the photosensitive layer residue 3a by the cleaning blade 13 becomes insufficient. As a result, the removal efficiency of the photosensitive layer 3 may be reduced. On the other hand, if the peripheral speed is too high, the centrifugal force increases, and when the photosensitive layer residue 3a is not dried, the photosensitive layer residue 3a, the solvent 14 and the like may be scattered. For the scraping drum 12, for example, a metal core made of a metal material such as stainless steel, iron, or aluminum is used. The scraping drum 12 cleans the surface of the photosensitive layer removing drum 11 by transferring the dissolved or swollen photosensitive layer residue 3a adhering to the surface of the photosensitive layer removing drum 11 to the surface. At this time, the photosensitive layer removing drum 11 carries a large amount of photosensitive layer residue 3a on its surface, and the scraping drum 12 has no bearing on its surface, so that the photosensitive layer removing drum 11 and the scraping drum 12 contact each other. The photosensitive layer residue 3a smoothly moves to the surface of the scraping drum 12 at the part.

  The peripheral speed and the rotation direction of the photosensitive member 2, the photosensitive layer removing drum 11, and the scraping drum 12 may be the same or different.

  The cleaning blade 13 is a plate-like member that extends in the longitudinal direction of the scraping drum 12 and is provided so that one end in the short side direction is detachably attached to the surface of the scraping drum 12 by a driving unit (not shown). The contact position of the cleaning blade 13 with the scraping drum 12 is on the downstream side of the contact position between the photosensitive layer removing drum 11 and the scraping drum 12 in the rotation direction of the scraping drum 12. As a result, the transfer of the photoconductor residue 3a transferred to the scraping drum 12 to the photosensitive layer removal drum 11 is prevented. The cleaning blade 13 is in a state in which one end in the short direction is separated from the surface of the scraping drum 12 and abuts against the surface of the scraping drum 12 every time the scraping drum 12 rotates several times. The layer residue 3a is removed. The transfer of the photosensitive layer residue 3a from the scraping drum 12 to the photosensitive layer removing drum 11 is unlikely to occur unless the amount of the photosensitive layer residue 3a attached to the scraping drum 12 becomes relatively large. Therefore, the photosensitive layer residue 3a can be removed very efficiently by bringing the cleaning blade 13 into contact each time the scraping drum 12 is rotated several times. The cleaning blade 13 may be a metal plate having elasticity, a synthetic resin plate, a combined plate of a metal plate and a synthetic resin plate, or the like.

  Further, the photosensitive layer removing apparatus 1 includes a detection unit, a control unit, and the like. There are a plurality of detection means, and the operation state of each member in the photosensitive layer removing apparatus 1 is detected. The control means controls the operation of each member in the photosensitive layer removing apparatus 1 according to the detection result by the detection means. The control means includes a storage unit, a calculation unit, and a control unit. In the storage unit of the control means, various set values serving as a reference for controlling the operation of each member in the photosensitive layer removing apparatus 1, detection results from detection means (not shown) arranged at various locations inside the photosensitive layer removing apparatus 1, A data table or the like for executing operation control is input. In addition, a program for executing various operation controls is written. As the storage unit, those commonly used in this field can be used, and examples thereof include a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD). The arithmetic unit takes out various data (setting values, detection results, data table, etc.) written in the storage unit and various operation control programs, and makes various determinations. The control unit sends a control signal to the corresponding device according to the determination result of the calculation unit, and performs operation control. The control unit and the calculation unit include a processing circuit constituted by a microcomputer, a microprocessor, and the like provided with a central processing unit (CPU). The control means includes a main power supply together with the processing circuit, and the power supply supplies driving power not only to the control means but also to each member in the photosensitive layer removing apparatus 1.

  According to the photosensitive layer removing apparatus 1, the photosensitive layer 3 is removed from the photoreceptor 2 through the solvent supply process, the photosensitive layer removing process, and the separation process, and the conductive substrate 4 is collected. In the solvent supply step, a solvent is brought into contact with the photosensitive layer 3 of the photoreceptor 2 to bring the photosensitive layer 3 into a dissolved or swollen state. Specifically, the solvent 14 is supplied from the solvent supply means 10 to the surface of the photoreceptor 2. At this time, the photosensitive member 2 is in a rotating state.

  In the photosensitive layer removing step, while rotating the photosensitive member 2 having the photosensitive layer 3 in a dissolved or swollen state, the photosensitive layer removing drum 11 is brought close to the photosensitive member 2, and the photosensitive layer removing drum 11 is moved several times to several hundreds. Rotate once. Since the photosensitive layer 3 contains a sufficient amount of solvent, the layered shape is deformed with the passage of time due to the rotation of the photosensitive member 2, and a part thereof adheres to the surface of the photosensitive layer removing drum 11. Starting from the adhered portion, the photosensitive layer 3 is wound around the photosensitive layer removing drum 11 and transferred to be removed from the photosensitive member 2. Of course, not all of the photosensitive layer 3 is transferred by winding, but may be transferred by simple adhesion due to the adhesiveness of the photosensitive layer 3. At this time, as the transfer of the photosensitive layer 3 from the photosensitive member 2 to the photosensitive layer removing drum 11 proceeds, the photosensitive member 2 is gradually brought closer to the photosensitive layer removing drum 11 and the gap between the photosensitive member 2 and the photosensitive layer removing drum 11 is increased. It is good to make it narrow. As a result, almost the entire amount of the photosensitive layer 3 on the surface of the photoreceptor 2 is transferred to the surface of the photosensitive layer removing drum 11 efficiently and reliably. Since the surface portion of the photosensitive layer 3 having the highest adhesion adheres to the surface of the photosensitive layer removing drum 11 and the transfer of the photosensitive layer 3 starts, the photosensitive layer 3 is transferred again from the photosensitive layer removing drum 11 to the photosensitive member 2. Does not happen. The photosensitive layer 3 is removed from the photosensitive member 2 by the photosensitive layer removing step, the conductive substrate 4 is collected, and a photosensitive member residue is carried on the surface of the photosensitive layer removing drum 11.

  In the separation step, the photoreceptor 2, that is, the conductive substrate 4 is separated from the photosensitive layer 3 removal character ram 11 carrying the photoreceptor residue. As a result, it is possible to reliably prevent damage to the conductive substrate 4 due to the photosensitive layer removing drum 11 in the rotating state, reattachment of the photosensitive layer residue 3a to the conductive substrate 4, and the like. The photosensitive layer residue 3 a on the photosensitive layer removing drum 11 moves to the surface of the scraping drum 12 by contacting the scraping drum 12. The photosensitive layer residue 3 a transferred to the surface of the scraping drum 12 is removed by the cleaning blade 13. At this time, since the peripheral speed of the scraping drum 12 is normally set to several tens to several hundreds of meters / minute, drying of the surface layer of the scraping drum 12 is promoted by the air flow relative to the peripheral speed of the scraping drum 12. Is done. Therefore, the peeling of the photosensitive layer residue 3a from the scraping drum 12 is relatively easy. In this embodiment, the cleaning blade 13 is used to remove the photosensitive layer residue 3a from the scraping drum 12. However, the cleaning blade 13 is not provided and the scraping drum 12 is periodically removed to remove the photosensitive member residue 3a. It may be removed. The above steps are repeated, the photosensitive layer 3 is removed from the photoreceptor 2, and the conductive substrate 44 is efficiently recovered.

  The photosensitive layer removing apparatus 1 employs a configuration in which the solvent 14 is supplied from the solvent supply means 10 to the surface of the photosensitive member 2, but is not limited thereto. For example, the photosensitive member 2 is immersed in a tank in which the solvent 14 is stored. After the photosensitive layer 3 is dissolved or swollen, it may be attached to the photosensitive layer removing apparatus 1 to remove the photosensitive layer 3.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In the following, “parts” and “%” respectively represent “parts by weight” and “% by weight” unless otherwise specified. In this embodiment, the following photoreceptors A to C were used. The photoreceptors A to C are obtained by laminating an undercoat layer, a charge generation layer and a charge transport layer or a charge generation layer and a charge transport layer in this order on an aluminum cylindrical conductive substrate having a diameter of 30 mm and a total length of 340 mm. It is. The charge transport layer is the outermost layer.

[Photoreceptor A]
Undercoat layer: 10 parts of dendritic titanium oxide (trade name: TTO-D-1, manufactured by Ishihara Sangyo Co., Ltd.) surface-treated with aluminum oxide and zirconium dioxide, Polycardnate (trade name: Iupilon Z200, Mitsubishi Engineering Plastics) 10 parts of Susu Co., Ltd. and 90 parts of cyclohexanone were mixed and dispersed with a paint shaker for 12 hours to prepare a coating solution for forming an undercoat layer. An undercoat layer having a thickness of 1.0 μm was formed by a dip coating method in which the coating solution for forming the undercoat layer was filled in a coating tank and the cylindrical conductive substrate was immersed in the coating tank and then pulled up.

  Charge generation layer: a crystal showing a clear diffraction peak at least at a Bragg angle (2θ ± 0.2 °) of 27.2 ° in an X-ray diffraction spectrum by Cu-Kα characteristic X-ray (wavelength: 1.54Å) as oxotitanium phthalocyanine 2 parts of oxotitanium phthalocyanine having a structure, 1 part of polyvinyl butyral (trade name: ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.) and 97 parts of methyl ethyl ketone are mixed and dispersed with a paint shaker to form a charge generating layer. A liquid was prepared. This charge generation layer forming coating solution was applied to the surface of the undercoat layer by the same dip coating method as that of the undercoat layer, thereby forming a charge generation layer having a thickness of 0.4 μm.

  Charge transport layer: 10 parts of a charge transport material of the following structural formula (I), 18 parts of polycarbonate (Iupilon Z200) and 0.1 part of 2,6-di-t-butyl-4-methylphenol (BHT) in 100 parts of tetrahydrofuran And a coating solution for forming a charge transport layer was prepared. The obtained charge transport layer forming coating solution was applied to the surface of the charge generation layer by a dip coating method to form a charge transport layer having a thickness of 30 μm.

[Photoreceptor B]
The structure is the same as that of the photoreceptor A except that the undercoat layer is not provided.

[Photoreceptor C]
Undercoat layer: 9 parts of dendritic titanium oxide (TTO-D-1) surface-treated with aluminum oxide and zirconium dioxide and 9 parts of copolymer nylon resin (trade name: CM8000, manufactured by Toray Industries, Inc.) The mixture was mixed with a mixed solvent of 41 parts of dioxolane and 41 parts of methanol and dispersed with a paint shaker for 8 hours to prepare a coating solution for forming an undercoat layer. An undercoat layer having a thickness of 1.0 μm was formed by a dip coating method in which the coating solution for forming the undercoat layer was filled in a coating tank and the cylindrical conductive substrate was immersed in the coating tank and then pulled up.
Charge generation layer: has the same structure as the charge generation layer in the photoreceptor A.
Charge transport layer: 10 parts of charge transport material of the following structural formula (II), 16 parts of polycarbonate (Iupilon Z300) and 0.1 part of 2,6-di-t-butyl-4-methylphenol (BHT) are added to 100 parts of tetrahydrofuran. And a coating solution for forming a charge transport layer was prepared. The obtained charge transport layer forming coating solution was applied to the surface of the charge generation layer by a dip coating method to form a charge transport layer having a thickness of 30 μm.

[Removal of photosensitive layer]
This was carried out using the photosensitive layer removing apparatus 1 shown in FIG. The photosensitive member 2, the photosensitive layer removing drum 11 and the scraping drum 12 are all rotated at a peripheral speed of 20 m / min, and the gap between the photosensitive member 2 and the photosensitive layer removing drum 11 is determined when the photosensitive layer removing operation starts ( When the supply of the solvent 14 to the surface of the photoreceptor 2 by the solvent supply means 10 was started), the thickness was 300 μm. The solvent 14 was sprayed onto the surface of the photoreceptor 2 at a rate of 10 cc / min by a liquid jet nozzle as the solvent supply means 10, and the dissolved photosensitive layer 3 was transferred to the surface of the photosensitive layer removing drum 11. At this time, the gap between the photosensitive member 2 and the photosensitive layer removing drum 11 was gradually narrowed with the progress of the removal of the photosensitive layer 3, and finally 50 μm. After removing the photosensitive layer 3 from the photoreceptor 2, the conductive substrate 4 was separated from the photosensitive layer removing drum 11 at a speed of 50 mm / sec. This is a common condition in the following examples and comparative examples.

(Example 1)
The photosensitive layer of the photoreceptor A was removed using cyclohexanone as the solvent 14.

(Example 2)
The photosensitive layer of the photoreceptor A was removed in the same manner as in Example 1 except that the scraping drum 12 was not used.

(Example 3)
The photosensitive layer of the photoreceptor A was removed in the same manner as in Example 1 except that the cleaning blade 13 was not contacted.

Example 4
Cyclohexanone was stored in a solvent storage tank, and the photosensitive member A was immersed in the solvent storage tank so that the photosensitive layer was dissolved and swollen. Then, the photosensitive layer was mounted on the photosensitive layer removing apparatus 1 and the photosensitive layer of the photosensitive member A was removed. Note that fresh cyclohexanone is supplied to the solvent storage tank at a rate of 10 cc per minute, and 1 liter of cyclohexanone is always stored.

(Example 5)
The photosensitive layer of the photoreceptor B was removed in the same manner as in Example 1 except that the photoreceptor B was used in place of the photoreceptor A.

(Example 6)
In the photosensitive layer removing apparatus 1, two liquid jet nozzles as the solvent supply means 10 are provided, one jets cyclohexanone at a rate of 10 cc / min, and the other jets a mixed solvent of methanol: benzyl alcohol = 8: 2 to 10 cc / min. It was configured to inject at a rate of minutes. The photosensitive member C was attached to the photosensitive layer removing apparatus, and cyclohexanone was first supplied, and when the undercoat layer was exposed, the mixed solvent was supplied to dissolve and swell the photosensitive layer. Thereafter, the photosensitive layer of the photoreceptor C was removed in the same manner as in Example 1.

(Comparative Example 1)
The photosensitive layer of the photosensitive member A is the same as in Example 1 except that the photosensitive member A (conductive substrate) is not separated from the photosensitive layer removing drum 11 after the photosensitive layer of the photosensitive member A is transferred to the photosensitive layer removing drum 11. Was removed.

(Comparative Example 2)
Except for maintaining the gap between the photosensitive member 2 and the photosensitive layer removing drum 11 at 300 μm at the start of the photosensitive layer removing operation without narrowing the gap as the photosensitive layer is removed, the photosensitive member A of the photosensitive member A is similar to the first embodiment. The photosensitive layer was removed.

(Comparative Example 3)
The photosensitive layer of the photoreceptor A was removed by scraping with a brush while supplying tetrahydrofuran at a rate of 10 cc / min.

(Comparative Example 4)
Tetrahydrofuran was stored in the dissolution storage tank, and the photosensitive member C was immersed therein to remove the photosensitive layer. Note that fresh tetrahydrofuran is supplied to the solvent storage tank at a rate of 10 cc per minute, and 3 liters of tetrahydrofuran is always stored.

(Evaluation)
The surface state of the conductive substrate 4 after removing the photosensitive layer in Examples 1 to 6 and Comparative Examples 1 to 4 and the adhesion state of the photosensitive layer residue 3a on the photosensitive layer removing drum 11 and the scraping drum 12 were evaluated. The surface state of the conductive substrate was visually observed for the presence or absence of circumferential flaws and evaluated according to the following criteria. ◯: No circumferential scratches were generated, and X: Circumferential scratches were evaluated. About the adhesion state of the photoreceptor residue in the photosensitive layer removal drum 11 and the scraping drum 12, the amount of deposits was observed visually and evaluated according to the following criteria. ○: No deposit (photosensitive layer residue 3a) is observed on the surface, Δ: A small amount of deposit remains on the surface, ×: A large amount of deposit remains on the surface. The results are shown in Table 1.

  From the results of Examples 1, 5, 6 and Comparative Example 1, the photosensitive layer residue and scratches are left on the conductive substrate 4 by separating the conductive substrate from the photosensitive layer removing drum 11 after the photosensitive layer is removed. Obviously, the photosensitive layer 3 can be removed. Further, from the results of Examples 1, 5, 6 and Comparative Example 2, the gap between the photosensitive member 2 and the photosensitive layer removing drum 11 is narrowed with the progress of the removal so that the photosensitive substrate 4 can be exposed without leaving any residue. It is clear that layer 3 can be removed. Further, from the results of Examples 1, 5, 6 and Comparative Example 3, when removing the photosensitive layer 3 from the photoreceptor 2, the photosensitive layer removing drum 11 which is a roller-like member and has a smooth surface is used. It is apparent that the photosensitive layer 3 can be removed without scratching the conductive substrate 4. Further, from the results of Examples 1, 4 to 6 and Comparative Example 4, it is clear that the photosensitive layer can be almost completely removed with a smaller amount of solvent 14. Further, from the results of Examples 1, 2, 5 and 6, it is clear that the photosensitive layer residue 3a on the surface of the photosensitive layer removing drum 11 is efficiently removed by using the scraping drum 12. Further, from the results of Examples 1, 3, 5, and 6, it is clear that the photosensitive layer residue 3a on the surface of the scraping drum 11 can be efficiently removed by using the cleaning blade 13.

It is sectional drawing which shows the structure of a photosensitive layer removal apparatus typically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive layer removal apparatus 2 Electrophotographic photoreceptor 3 Photosensitive layer 4 Conductive substrate 3a Photosensitive layer residue 10 Solvent supply means 11 Photosensitive layer removal drum 12 Scraping drum 13 Cleaning blade 14 Solvent

Claims (5)

A solvent supplying step of dissolving or swelling the photosensitive layer by bringing an organic solvent into contact with the photosensitive layer of the electrophotographic photoreceptor including the conductive substrate and the photosensitive layer provided on the surface of the conductive substrate;
When the photosensitive layer removing drum in a rotating state is brought close to the electrophotographic photosensitive member and the photosensitive layer in a dissolved or swollen state is transferred to the surface of the photosensitive layer removing drum to remove the photosensitive layer, the electron is removed as the photosensitive layer is removed. A photosensitive layer removing method comprising a photosensitive layer removing step of narrowing a gap between a photographic photosensitive member and a photosensitive layer removing drum.   2. The photosensitive layer according to claim 1, further comprising a separation step of separating the photosensitive layer removing drum carrying the photosensitive layer on the surface of the photosensitive substrate after the photosensitive layer is removed from the conductive substrate from which the photosensitive layer has been removed. Removal method.   3. The method for removing a photosensitive layer according to claim 1, wherein the photosensitive layer on the surface of the photosensitive layer removing drum is removed by moving to the surface of the scraping drum.   4. The method for removing a photosensitive layer according to claim 3, wherein after the organic solvent is volatilized from the photosensitive layer on the surface of the scraping drum, the photosensitive layer is removed by bringing a blade into contact with the surface of the scraping drum.   The method for removing a photosensitive layer according to claim 1, wherein the organic solvent is sprayed from a nozzle to bring the organic solvent into contact with the photosensitive layer.

Images