JPH06230591A - Electrophotographic sensitive body and electrophotographic device with the same - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body having a reduced coefft. of friction of the surface layer, cleanability, wear and scuffing resistance, not raising residual potential in repeated electrophotographic processes and always giving a high grade image. CONSTITUTION:The objective electrophotographic sensitive body with a photosensitive layer on the electric conductive substrate contains fluororesin particles and a fluorine-contg. pectinate graft copolymer heat-treated and purified by reprecipitation in the surface layer. The objective electrophotographic device has the electrophotographic sensitive body. The electrophotographic sensitive body has resistance to wear and scuffing of the surface due to friction, stably gives a high grade image even at a high humidity and is excellent in cleanability.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrophotographic photoreceptor,
More specifically, the present invention relates to an electrophotographic photoreceptor having excellent durability with little deterioration in image quality due to repeated use.

[0002]

2. Description of the Related Art An electrophotographic photosensitive member is required to have sensitivity, electrical characteristics and optical characteristics according to an electrophotographic process to be applied. Since electrical and mechanical external forces are directly applied to the toner by processes such as charging, toner development, transfer to paper, and cleaning, durability against these is required. Specifically, it is required to have durability against abrasion of the surface due to friction, generation of scratches, deterioration of the surface under high humidity and the like. Further, there is a problem that the toner adheres to the surface layer by repeating the development and cleaning with the toner, and for this, improvement of the cleaning property of the surface layer is required. Various methods have been studied in order to satisfy the properties required for the surface layer as described above. Among them, means for providing a resin layer in which fluorine resin particles are dispersed on the surface are:
It is effective. Dispersion of the fluorine-based resin particles has the effect of reducing the friction coefficient of the surface layer, improving cleaning properties, and improving durability against abrasion and scratches. However, in the dispersion of the fluorine-based resin particles, there is a problem in the dispersibility and cohesiveness, it is difficult to form a uniform and smooth film, the surface layer obtained, image defects such as image unevenness and pinholes It was unavoidable to have. In most cases, a binder resin having good dispersibility, a dispersion aid, and the like have deteriorated electrophotographic characteristics, and no effective one has been found. When a fluorine-based comb-type graft polymer is used as an example of the dispersion aid, the dispersibility of the fluorine-based resin particles is good, but there arises a problem that image quality deteriorates due to repeated use under high humidity. That is, the residual potential increased due to repeated use, and image fogging occurred. The cause is that the organic salts contained as impurities in the fluorine-based comb-type graft polymer act with water to increase the residual potential. Therefore, various purification methods such as reprecipitation and washing have been tried, but sufficient ones have not been obtained.

[0003]

SUMMARY OF THE INVENTION The present invention is intended to provide an electrophotographic photosensitive member which meets the above-mentioned requirements. That is, the object of the present invention is to reduce the friction coefficient of the surface layer, having cleaning properties, durability against abrasion and scratches, and no increase in residual potential in repeated electrophotographic processes, and always obtain a high-quality image. An object is to provide an electrophotographic photoreceptor obtained.

[0004]

That is, the present invention relates to an electrophotographic photosensitive member having a photosensitive layer on a conductive support, in which the surface layer of the photosensitive member is a fluorine-based resin particle, and the surface layer after the heat treatment is regenerated. An electrophotographic photoreceptor comprising a fluorine-based comb-type graft polymer that has been precipitated and purified.

The present invention will be described in detail below.

As a method for purifying the fluorine-based comb-type graft polymer used in the present invention, reprecipitation purification is performed after heat treatment.

Examples of the heat treatment method for the fluorine-type comb-type graft polymer include heating with a warm air dryer, an electric furnace, an infrared heating furnace, a far infrared heating furnace, and the like.

It is necessary that the heat treatment temperature is not lower than the Tg (glass transition temperature) of the polymer and that the polymer is not thermally decomposed. Specifically, 60-250 ℃
Is preferred, and particularly preferably 80 to 200 ° C.

The reprecipitation purification is a purification method in which the substance to be purified is dissolved in a good solvent and the solution is added dropwise to a poor solvent for purification. As a good solvent used for the purification of the fluorine-type comb polymer of the present invention, Is preferably one that has good solubility in the fluorine-based graft polymer to be purified, and examples thereof include ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone;
Examples thereof include ethers such as diethyl ether and tetrahydrofuran; esters such as ethyl acetate and butyl acetate; hydrocarbons such as toluene and benzene; halogenated hydrocarbons such as chlorobenzene.

As the poor solvent, those having a low solubility in the fluorine-based graft polymer to be purified are suitable. Examples thereof include alcohols such as methanol, ethanol, butanol, isopropyl alcohol; normal hexane, petroleum ether, Hydrocarbons such as cyclohexane, water, etc. may be mentioned.

For reprecipitation purification, the substance to be purified is dissolved in a good solvent and this solution is added dropwise to a poor solvent for purification, and conversely, the substance to be purified is dissolved in a good solvent and then diluted in this solution. There is a method of purifying by dropping a solvent, but in the present invention, each method can be appropriately selected.

When the solution in which the substance to be purified is dissolved is dropped into the poor solvent, it is preferable to add the solution while stirring the poor solvent.

The method for purifying the fluorine-type comb polymer used in the present invention includes reprecipitation purification after heat treatment and other purification methods such as general reprecipitation purification without extraction, washing and heat treatment. It is possible to combine. When the fluorine-type comb-type graft polymer is obtained in the form of a solution, it is preferably purified after being solidified by some means.

The fluorine-type comb-type graft polymer used in the present invention comprises a macromonomer composed of a relatively low molecular weight oligomer having a polymerizable functional group at one end of each molecular chain and a relatively low molecular weight oligomer, and fluorine. It is obtained by copolymerizing a system-polymerizable monomer, and has a structure in which a fluoropolymer is a backbone and a polymer of a macromonomer hangs like a plate. For the macromonomer, those that have an affinity with the resin to which the graft polymer is added are selected,
For example, polymers and copolymers of acrylic acid esters, methacrylic acid esters, styrene compounds and the like are used.

On the other hand, as the fluorine-based polymerizable monomer,
Hereinafter, one or more polymerizable monomers having a fluorine atom in the side chain as in (1) to (6) are used.
It is not limited to this.

[0016]

[Chemical 1]

[In the formula, R ₁ represents a hydrogen atom or a methyl group. R ₂ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a nitrile group, and a combination of several kinds thereof may be used. n is an integer of 1 or more, m is an integer of 1 to 5, k is an integer of 1 to 4, and m + k = 5. ) The content of the fluorine-based monomer residue in the fluorine-type comb-type graft polymer is 5 to 9 in the fluorine-type comb-type graft polymer.
0 wt% is preferable, and 10 to 70 wt% is more preferable. If the content of the fluorine-based monomer residue is less than 5% by weight, the hydrophobic modification effect cannot be sufficiently exerted, and if the content of the fluorine-based monomer residue is more than 90% by weight, it is dissolved with the macromonomer. The sex becomes worse.

The fluorine resin particles used in the present invention include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, and difluorodichloroethylene. It is desirable to appropriately select one kind or two or more kinds from the resin and the copolymer thereof, and the tetrafluoroethylene resin and the vinyldenfluoride resin are particularly preferable. The molecular weight of the resin and the particle size of the particles can be appropriately selected and are not particularly limited.

The presence of the fluorine-based graft polymer improves the dispersibility of the fluorine-based resin particles and prevents agglomeration during the coating film formation, so that a very uniform and smooth Teflon dispersion layer is formed. Further, since the fluorine-based graft polymer has the structure as described above, it has excellent compatibility with the coating liquid containing the binder resin for forming the resin layer, and therefore does not migrate or ooze onto the surface layer. . Further, stable charge characteristics can be obtained without accumulation of residual charges due to repeated electrophotographic processes. The content of the fluorine-based resin particles to be dispersed is appropriately 1 to 40%, particularly preferably 5 to 30%, based on the weight of the solid content. If the content is less than 1%, the modifying effect due to the dispersion of the fluorine-based resin particles is not sufficient, while if it exceeds 50%, the light transmitting property is lowered and the carrier mobility is also lowered. Further, the content of the fluorine-based graft polymer is appropriately 0.01 to 10% based on the weight of the solid content, and particularly preferably 0.02 to 2%. 0.01%
If it is less than 10%, the effect of improving the dispersibility of the fluorine-based resin particles is not sufficient, while if it exceeds 10%, the graft polymer will be present not only on the surface of the coating film but also in the bulk, which may cause compatibility problems with the resin. However, accumulation of residual charges occurs when the electrophotographic process is repeated. The binder resin for forming the resin layer may be a polymer having film-forming properties, but it should also have a certain degree of hardness by itself.
Polymethacrylic acid esters, polycarbonates, polyacrylates, polyesters, polysulfones and the like are preferable because they do not interfere with carrier transportation.

As an example of a method for preparing a coating solution for preparing the electrophotographic photosensitive member of the present invention, a method of simultaneously dispersing a binder resin, a charge transfer agent and the like together with a solvent, fluorine resin particles and a fluorine comb type graft polymer. Further, there may be mentioned a method in which the fluorine-based resin particles, the fluorine-based comb-type graft polymer and the binder resin are previously dispersed to prepare a dispersion, and the dispersion is mixed with the previously-dispersed coating liquid. In the preparation of the coating liquid for electrophotographic photoreceptor or the fluororesin particle dispersion liquid used in the present invention, simple stirring and mixing may be used, but if necessary, a dispersing means such as a ball mill, a roll mill or a sand mill is used.

Coating liquid for electrophotographic photoreceptor used in the present invention,
Alternatively, as the solvent used for preparing the fluororesin particle dispersion liquid, a solvent that is good in the binder resin in the coating liquid, the solubility in the charge transport material, the dispersibility in the pigment, and the coating property is selected.

Examples of the material of the conductive support used in the electrophotographic photosensitive member of the present invention include metals such as aluminum, copper, nickel and silver or alloys thereof; conductive such as antimony acetate, indium oxide and tin oxide. Examples of the resin include a metal oxide, carbon fiber, carbon black, and a mixture of graphite powder and resin.

Further, it is possible to provide a conductive layer on the support for covering defects on the support and protecting the support. For example, metal powder of aluminum, copper, nickel, silver, etc .; antimony oxide, oxidation. Conductive metal oxides such as indium and tin oxide; polymer conductive materials such as polypyrrole, polyaniline, and polymer electrolytes; carbon fibers, carbon black, graphite powder; or conductive powders whose surfaces are coated with these conductive substances. The conductive material of the thermoplastic resin such as acrylic resin, polyester resin, polyamide resin, polyvinyl acetate resin, polycarbonate resin, polyvinyl butyral resin; thermosetting resin such as polyurethane resin, phenol resin, epoxy resin; Dispersed in binder resin, add additives as needed One coated things onto a support.

Further, an intermediate layer may be provided in order to improve the adhesiveness of the photosensitive layer and the charge injection property from the support. Examples of the material for the intermediate layer include gelatin, ethylene / acrylic acid copolymer, nitrocellulose resin, polyamide resin, polyvinyl alcohol resin, polyvinyl alcohol resin, and other resins. Those prepared by dissolving these in an appropriate solvent are supported. Apply to. It is also possible to add an additive as needed.

The photosensitive layer may have a single layer structure or a laminated structure in which a charge generation layer and a charge transport layer are functionally separated.

Examples of the material for the charge generation layer of the laminated structure photoreceptor include azo pigments such as sudan red and chlordian blue, phthalocyanine pigments such as copper phthalocyanine and titanyl phthalocyanine, quinone pigments such as anthanthrone, perylene pigments and indigo pigments. A charge generating substance such as a thermoplastic resin such as an acrylic resin, a polyester resin, a polyamide resin, a polyvinyl acetate resin, a polycarbonate resin, a polyvinyl butyral resin, a polyvinyl benzal resin; a thermosetting resin such as a polyurethane resin, a phenol resin or an epoxy resin. And a coating method in which the resin is dispersed in a suitable solvent. Further, it is possible to add additives as required.

Examples of the material for the charge transport layer include charge transport materials such as hydrazone compounds, stibene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, triarylmethane compounds, and acrylic resins, polyester resins, and poly resins. Thermoplastic resin such as arylate resin, polyvinyl chloride resin, polycarbonate resin, polyvinyl butyral resin, polymethacrylate resin; polyurethane resin, binder resin such as phenol resin and thermosetting resin such as epoxy resin, methanol, ethanol, butanol, isopropyl alcohol , And other alcohols. Ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone; ethers such as diethyl ether and tetrahydrofuran; esters such as ethyl acetate and propyl acetate; hydrocarbons such as normal hexane, petroleum ether, toluene; monochlorobenzene, dichloromethane Examples thereof include those dispersed in other suitable solvents such as halogenated hydrocarbons, etc., and those coated with those to which additives are added as required. Also, a conductive polymer can be used.

As the coating method used in the present invention, a dip coating method, a spray coating method, a roll coater coating method, a gravure coater coating method and the like can be applied.

In the present invention, the layer containing the fluorine-based resin particles and the fluorine-based comb-type graft polymer purified by re-precipitation after heat treatment is used as the surface layer of the photoreceptor (direct contact with toner, developing device, cleaning device, etc.). Layer) is effective. As an example of the layer structure of the photoconductor, in the case of a single-layer structure, the photoconductor layer is the charge transport layer, and in the laminated photoconductor in which the charge transport layer is provided on the charge generation layer, the charge generation is performed on the charge transport layer. It can be used as a conductive layer in a laminated photoconductor of the type in which a layer is further provided with a conductive layer, and as a protective layer in a photoconductor in which a protective layer is provided on the photosensitive layer.

FIG. 1 shows a schematic structural example of a general transfer type electrophotographic apparatus using the electrophotographic photosensitive member of the present invention.

In the figure, reference numeral 1 denotes a drum type photosensitive member of the present invention as an image bearing member, which is rotationally driven around a shaft 1a in a direction of an arrow at a predetermined peripheral speed. The photosensitive member 1 is uniformly charged at its peripheral surface by a charging unit 2 at a predetermined positive or negative potential in the course of its rotation, and then at an exposure unit 3 an optical image exposure L (slit exposure Laser beam scanning exposure). As a result, electrostatic latent images corresponding to the exposed image are sequentially formed on the peripheral surface of the photoconductor.

The electrostatic latent image is then toner-developed by the developing means 4, and the toner-developed image is rotated by the transfer means 5 between the photoconductor 1 and the transfer means 5 from a paper feeding portion (not shown). The images are sequentially transferred onto the surface of the transfer material P that is synchronously taken out and fed.

The transfer material P which has received the image transfer is separated from the surface of the photoconductor and is introduced into the image fixing means 8 where it is subjected to the image fixing and printed out as a copy.

The surface of the photoconductor 1 after the image transfer is cleaned by the cleaning means 6 to remove the residual toner after transfer, and is further discharged by the pre-exposure means 7 to be repeatedly used for image formation.

As the uniform charging means 2 for the photoconductor 1, a corona charging device is generally widely used. In addition, the transfer device 5
Corona transfer means are also widely used. The electrophotographic apparatus is configured by integrally combining a plurality of constituent elements such as the photoconductor, the developing unit, and the cleaning unit described above as an apparatus unit, and the unit is configured to be detachable from the apparatus body. May be. For example, the photoconductor 1
Alternatively, the cleaning unit 6 and the cleaning unit 6 may be integrated into one unit, and may be detachably configured by using a guide unit such as a rail of the apparatus main body. At this time, the above device unit may be provided with a charging unit and / or a developing unit.

When the electrophotographic apparatus is used as a copying machine or a printer, the light image exposure L is reflected light or transmitted light from a document, or the document is read and converted into a signal, and scanning of the laser beam or LED array is performed by this signal. Drive or liquid crystal shutter array drive.

When used as a printer for a facsimile, the optical image exposure L becomes an exposure for printing received data. FIG. 2 is a block diagram showing an example of this case.

The controller 11 controls the image reading section 10 and the printer 19. The entire controller 11 is CP
It is controlled by U17. The read data from the image reading unit 10 is transmitted to the partner station through the transmission circuit 13. The data received from the partner station is sent to the printer 19 through the receiving circuit 12. The image memory 16 stores predetermined image data. The printer controller 18 controls the printer 19. 14 is a telephone.

The image information received from the line 15 (image information from a remote terminal connected via the line) is demodulated by the receiving circuit 12, then decoded by the CPU 17, and sequentially stored in the image memory 16. Is stored. When the image information of at least one page is stored in the memory 16, the image recording of that page is performed. The CPU 17 reads out one page of image information from the memory 16 and sends the decoded one page of image information to the printer controller 18. Upon receiving the image information of one page from the CPU 17, the printer controller 18 controls the printer 19 to record the image information of the page.

The CPU 17 is receiving the next page while the printer 19 is recording.

The image is received and recorded as described above.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines but also in laser beam printers, C
RT printer, LED printer, liquid crystal printer,
It can be widely used in electrophotographic application fields such as laser plate making.

[0043]

EXAMPLES The present invention will be described in more detail with reference to specific examples.

Example 1 As a conductive layer coating step, conductive titanium oxide coated with tin oxide containing 10% antimony oxide 2000 parts by weight phenol resin 2500 parts by weight methyl cellosolve 2000 parts by weight methanol 500 parts by weight φ1 mm glass beads Was dispersed for 2 hours in a sand mill apparatus using to prepare a conductive layer coating solution.

Aluminum cylinder (φ30mm × 36
(0 mm), the above coating composition was applied by dipping, and then dried at 160 ° C. for 25 minutes by a drying device. The thickness of the conductive layer is 20 μm
Met.

Next, as an intermediate layer coating step, re-precipitation refined N-methoxymethylated nylon 6 1000 parts by weight 6,12,66,610 copolymerized nylon 250 parts by weight was dissolved in methanol 5000 parts by weight butanol 5000 parts by weight to form an intermediate layer. A layer coating solution was prepared. The above coating material was further applied by dip coating on the above-mentioned aluminum cylinder on which the conductive layer had been coated, and dried at 95 ° C. for 7 minutes by a drying device. The thickness of the intermediate layer was 0.50 μm.

Next, as a coating step of the charge generation layer, 400 parts by weight of a disazo pigment having the following structural formula is used.

[0048]

[Chemical 2]

Polyvinyl butyral resin 200 parts by weight (butyralization rate 68%, average molecular weight 24000) Cyclohexanone 5000 parts by weight was used in a sand mill apparatus using φ1 mm glass beads to prepare 24
After time-dispersed, 5,000 parts by weight of tetrahydrofuran was further added to prepare a charge generation layer coating solution. Furthermore, this solution is separated into beads with a centrifuge (7000 rpm, 30 minutes),
I removed trash. The above charge generation layer coating material was dip-coated on the aforementioned intermediate layer-coated cylinder and dried at 85 ° C. for 7 minutes. The film thickness of the charge generation layer was 0.15 μm.

Next, in the step of purifying the fluorine-type comb-type graft polymer, 700 parts by weight (solid content 25%) of fluorine-type comb-type graft polymer (trade name: GF-300, manufactured by Toagosei Co., Ltd.) was added at 100 ml / min. 7 at dropping speed
It was added dropwise to 000 parts by weight of methanol. The formed precipitate was separated from methanol by suction filtration and then dissolved in 500 parts by weight of methyl ethyl ketone. Add this solution to 10
The mixture was dropped into 7,000 parts by weight of methanol at a dropping rate of 0 ml / min to carry out reprecipitation purification. The precipitate formed is separated by suction filtration from methanol and then collected by a vacuum dryer.
It was dried at 0 ° C. for 24 hours. The thus obtained twice reprecipitated and purified precipitate was further heated in an electric furnace at 150
Heat treatment was performed at ℃ for 2 hours. After cooling, it was dissolved in 500 parts by weight of methyl ethyl ketone. 100 ml of this solution
It was dropped into 7,000 parts by weight of methanol at a dropping rate of min and reprecipitated for purification. The formed precipitate is separated from methanol by suction filtration and recovered, and then dried at 50 ° C. in a vacuum dryer for 2 hours.
A fluorine-type comb-type graft polymer was prepared by drying for 4 hours, heat treatment, and reprecipitation purification.

Next, as a process for preparing a tetrafluoroethylene resin particle (powder) dispersion, tetrafluoroethylene resin powder (trade name: Lubron L-2, manufactured by Daikin Industries, Ltd.) 100 parts by weight Polycarbonate resin 100 parts by weight Fluorine-type comb-type graft polymer purified by the above process 8 parts by weight Monochlorobenzene 500 parts by weight was thoroughly mixed, and then dispersed with a sand grinder (manufactured by Imex Co., Ltd.) using glass beads to obtain tetrafluoroethylene. A resin powder dispersion was prepared.

Next, 1200 parts by weight of a styryl compound having the following structural formula

[0053]

[Chemical 3]

Polycarbonate resin 800 parts by weight Polytetrafluoroethylene resin powder dispersion 1500 parts by weight was dissolved and mixed in monochlorobenzene 5000 parts by weight dichloromethane 3000 parts by weight to prepare a charge transport layer coating solution. This liquid was dip-coated on the aluminum cylinder on which the charge generation layer had been coated, and dried at 130 ° C. for 40 minutes. The film thickness of the charge transport layer was 25 μm.

This electrophotographic photosensitive member was subjected to a process of charging, exposure and strong exposure with an electrophotographic photosensitive member tester (manufactured by Kawaguchi Denki Co., Ltd.) under high temperature and high humidity of 35 ° C. and 80%.
The change in residual potential (surface potential after strong exposure) was repeated 10,000 times in a 5-second cycle, and the results are shown in Table 1.

This electrophotographic photosensitive member is charged, exposed, developed,
The copying and repeating the transfer and cleaning processes were repeated every 0.5 second, and the copying machine was mounted, and 10,000 copies were continuously made under a high temperature and high humidity condition of 35 ° C. and 80%. As a result, a high-quality image having no image defect was obtained both in the initial stage and on the 10000th sheet.

Example 2 As a step of purifying a fluorine-type comb-type graft polymer, a fluorine-type comb-type graft polymer (trade name: LF-4)
0, 300 parts by weight of Soken Chemical Industry Co., Ltd., 50 ml / mi
It was added dropwise to 8000 parts by weight of methanol at a dropping rate of n. The formed precipitate was separated from methanol by suction filtration, and then the precipitate was dried by a vacuum dryer at 60 ° C. for 24 hours.

Further, this precipitate is 180 in an electric furnace.
It was heat-treated at ℃ for 1 hour. After cooling, it was dissolved in 300 parts by weight of ethyl acetate. This solution was dropped into 7000 parts by weight of methanol at a dropping rate of 50 ml / min to perform reprecipitation purification. The produced precipitate was separated from methanol by suction filtration and recovered, and then dried by a vacuum dryer at 60 ° C. for 24 hours.

Next, as a process for preparing a tetrafluoroethylene resin powder dispersion, tetrafluoroethylene resin powder (trade name: Lubron L-2, manufactured by Daikin Industries, Ltd.) 100 parts by weight Polycarbonate resin 100 parts by weight Purified by the above steps 10 parts by weight of fluorine-type comb polymer and 600 parts by weight of monochlorobenzene were thoroughly mixed and dispersed by a sand grinder (made by AIMEX Co., Ltd.) using glass beads to prepare a tetrafluoroethylene resin powder dispersion liquid. did.

Using this tetrafluoroethylene resin powder dispersion, a charge transport layer coating solution was prepared in exactly the same manner as in Example 1. This solution was dip-coated on an aluminum cylinder on which a charge generation layer had been coated, as in Example 1, and dried at 130 ° C. for 40 minutes. The film thickness of the charge transport layer was 25 μm.

This electrophotographic photosensitive member was subjected to a process of charging, exposure and strong exposure in an electrophotographic photosensitive member tester (manufactured by Kawaguchi Denki Co., Ltd.) under high temperature and high humidity of 35 ° C. and 80%.
The change in residual potential was measured 10,000 times repeatedly in a 5-second cycle, and the results are shown in Table 1.

This electrophotographic photosensitive member is charged, exposed, developed,
The copying and repeating the transfer and cleaning processes were repeated every 0.5 second, and the copying machine was mounted, and 10,000 copies were continuously made under a high temperature and high humidity condition of 35 ° C. and 80%. As a result, a high-quality image having no image defect was obtained both in the initial stage and on the 10000th sheet.

Example 3 As a step of purifying a fluorine-type comb-type graft polymer, a fluorine-type comb-type graft polymer (trade name: GF-15) was used.
0, Zinc Synthetic Co., Ltd.) 400 parts by weight of 50 ml / mi
It was dripped into 6000 parts by weight of methanol at a dropping rate of n. The formed precipitate was separated from methanol by suction filtration, and then the precipitate was dried by a vacuum dryer at 60 ° C. for 24 hours.

Further, this precipitate is heated to 200 in an electric furnace.
It was heat-treated at ℃ for 1 hour. After cooling, it was dissolved in 400 parts by weight of ethyl acetate. This solution was dropped into 6000 parts by weight of methanol at a dropping rate of 50 ml / min. The produced precipitate was separated from methanol by suction filtration and recovered, and then dried by a vacuum dryer at 60 ° C. for 24 hours.

Next, as a process for preparing a polytrifluorochloroethylene resin powder dispersion, polytrifluoroethylene resin powder (trade name: Daiflon, manufactured by Daikin Industries, Ltd. 100 parts by weight polycarbonate resin 100 parts by weight) 4 parts by weight of the fluorine-based graft polymer purified by 1. 600 parts by weight of monochlorobenzene were thoroughly mixed, and then dispersed with a sand grinder (manufactured by IMEX Co., Ltd.) using glass beads to obtain a polytrifluoroethylene chloride resin. A powder dispersion was prepared.

Using this poly (trifluorochloroethylene) resin powder dispersion, a charge transport layer coating solution was prepared in exactly the same manner as in Example 1. This solution was dip-coated on an aluminum cylinder on which a charge generation layer had been coated as in Example 1, and dried at 130 ° C. for 60 minutes. The film thickness of the charge transport layer was 25 μm.

This electrophotographic photosensitive member was subjected to a process of charging, exposure and strong exposure with an electrophotographic photosensitive member tester (manufactured by Kawaguchi Denki Co., Ltd.) under high temperature and high humidity of 35 ° C. and 80%.
The change in residual potential was measured 10,000 times repeatedly in a 5-second cycle, and the results are shown in Table 1.

This electrophotographic photosensitive member is charged, exposed, developed,
The copying and repeating the transfer and cleaning processes were repeated every 0.5 second, and the copying machine was mounted, and 10,000 copies were continuously made under a high temperature and high humidity condition of 35 ° C. and 80%. As a result, a high-quality image having no image defect was obtained both in the initial stage and on the 10000th sheet.

Example 4 Polyvinylidene fluoride resin powder dispersion preparation process Polyvinylidene fluoride resin powder 100 parts by weight Polycarbonate resin 100 parts by weight Fluorine-based comb-type graft polymer purified in Example 1 8 parts by weight Monochlorobenzene 600 parts by weight The parts were thoroughly mixed and then dispersed with a sand grinder (manufactured by Imex Co., Ltd.) using glass beads to prepare a polyvinylidene fluoride resin powder dispersion.

Using this polyvinylidene fluoride resin powder dispersion, a charge transport layer coating solution was prepared in exactly the same manner as in Example 1. This solution was dip-coated on an aluminum cylinder on which a charge generation layer had been coated in the same manner as in Example 1, and the coating was carried out at 130 ° C. for 60
Min dried. The film thickness of the charge transport layer was 20 μm.

This electrophotographic photosensitive member was subjected to a process of charging, exposure and strong exposure with an electrophotographic photosensitive member tester (manufactured by Kawaguchi Denki Co., Ltd.) under high temperature and high humidity of 35 ° C. and 80%.
The change in residual potential was measured 10,000 times repeatedly in a 5-second cycle, and the results are shown in Table 1.

This electrophotographic photosensitive member is charged, exposed, developed,
The copying and repeating the transfer and cleaning processes were repeated every 0.5 second, and the copying machine was mounted, and 10,000 copies were continuously made under a high temperature and high humidity condition of 35 ° C. and 80%. As a result, a high-quality image having no image defect was obtained both in the initial stage and on the 10000th sheet.

Example 5 The same styryl compound as in Example 1 1200 parts by weight Polycarbonate resin 1000 parts by weight was dissolved in monochlorobenzene 5000 parts by weight dichloromethane 3000 parts by weight to prepare a charge transport layer coating solution. This liquid was applied by dipping the coating material for the charge transport layer onto an aluminum cylinder on which the charge generation layer had been coated as in Example 1, and the coating was carried out at 130 ° C. for 4 hours.
Dry for 0 minutes. The film thickness of the charge transport layer was 25 μm.

As a process for preparing the following tetrafluoroethylene resin powder dispersion liquid, tetrafluoroethylene resin powder (trade name: Lubron L-2, manufactured by Daikin Industries, Ltd.) 50 parts by weight Polycarbonate resin 120 parts by weight Example 1 4 parts by weight of the fluorine-type comb-type graft polymer purified in Step 5 was thoroughly mixed with 500 parts by weight of monochlorobenzene, and then dispersed with a sand grinder (manufactured by IMEX Co., Ltd.) using glass beads to disperse a tetrafluoroethylene resin powder. A liquid was created.

Further, the tetrafluoroethylene powder dispersion was spray-coated on the photoconductor drum coated with the charge transport layer and dried at 130 ° C. for 10 minutes to form a protective layer. The thickness of the protective layer was 4 μm.

This electrophotographic photosensitive member is charged, exposed, developed,
The copying and repeating the transfer and cleaning processes were repeated every 0.5 second, and the copying machine was mounted, and 10,000 copies were continuously made under a high temperature and high humidity condition of 35 ° C. and 80%. As a result, a high-quality image having no image defect was obtained both in the initial stage and on the 10000th sheet.

Comparative Example 1 In the same manner as in Example 1, except that the heat treatment step was not performed in the refining process of the fluorine-based comb-type graft polymer of Example 1 and the re-precipitation purification was performed only three times. An electrophotographic photoreceptor was prepared in exactly the same manner.

This electrophotographic photosensitive member was subjected to a process of charging, exposure and strong exposure in an electrophotographic photosensitive member tester (manufactured by Kawaguchi Electric Co., Ltd.) at a high temperature of 35 ° C. and a high humidity of 80%.
The change in residual potential was measured 10,000 times repeatedly in a 5-second cycle, and the results are shown in Table 1.

This electrophotographic photosensitive member is charged, exposed, developed,
The copying and repeating the transfer and cleaning processes were repeated every 0.5 second, and the copying machine was mounted, and 10,000 copies were continuously made under a high temperature and high humidity condition of 35 ° C. and 80%. As a result, a good image was obtained in the initial stage, but fogging occurred and a good image was not obtained on the 10000th sheet. As a result of measuring the change in residual potential, it was higher than in the initial stage.

Comparative Example 2 The same as Example 2 except that the heat treatment step was not performed in the purification step of the fluorine-based comb-type graft polymer of Example 2 and the fluorine-type comb-type graft polymer was used only for two reprecipitation purifications. An electrophotographic photoreceptor was prepared in exactly the same manner.

This electrophotographic photosensitive member was subjected to a process of charging, exposure and strong exposure with an electrophotographic photosensitive member tester (manufactured by Kawaguchi Denki Co., Ltd.) under high temperature and high humidity of 35 ° C. and 80%.
The change in residual potential was measured 10,000 times repeatedly in a 5-second cycle, and the results are shown in Table 1.

This electrophotographic photosensitive member is charged, exposed, developed,
The copying and repeating the transfer and cleaning processes were repeated every 0.5 second, and the copying machine was mounted, and 10,000 copies were continuously made under a high temperature and high humidity condition of 35 ° C. and 80%. As a result, a good image was obtained in the initial stage, but fogging occurred and a good image was not obtained on the 10000th sheet. As a result of measuring the change in residual potential, it was higher than in the initial stage.

Comparative Example 3 The same as Example 3 except that the heat treatment step was not performed in the purification step of the fluorine-based comb-type graft polymer of Example 3 and only the re-precipitation purification was performed twice. An electrophotographic photoreceptor was prepared in exactly the same manner.

This electrophotographic photosensitive member was subjected to a process of charging, exposure and strong exposure in an electrophotographic photosensitive member tester (manufactured by Kawaguchi Electric Co., Ltd.) under high temperature and high humidity of 35 ° C. and 80%.
The change in residual potential was measured 10,000 times repeatedly in a 5-second cycle, and the results are shown in Table 1.

This electrophotographic photosensitive member was charged, exposed, developed,
The copying and repeating the transfer and cleaning processes were repeated every 0.5 second, and the copying machine was mounted, and 10,000 copies were continuously made under a high temperature and high humidity condition of 35 ° C. and 80%. As a result, a good image was obtained in the initial stage, but fogging occurred and a good image was not obtained on the 10000th sheet. As a result of measuring the change in residual potential, it was higher than in the initial stage.

Comparative Example 4 The fluorine-type comb-type graft polymer used in the purification step of the fluorine-type comb-type graft polymer of Example 4 was subjected to the reprecipitation purification only three times without the heat treatment step used in Comparative Example 1. An electrophotographic photosensitive member was prepared in the same manner as in Example 4 except for the above.

This electrophotographic photosensitive member was subjected to a process of charging, exposure and strong exposure with an electrophotographic photosensitive member tester (manufactured by Kawaguchi Electric Co., Ltd.) at a temperature of 35 ° C. and high humidity of 80%.
The change in residual potential was measured 10,000 times repeatedly in a 5-second cycle, and the results are shown in Table 1.

This electrophotographic photoreceptor is charged, exposed, developed,
The copying and repeating the transfer and cleaning processes were repeated every 0.5 second, and the copying machine was mounted, and 10,000 copies were continuously made under a high temperature and high humidity condition of 35 ° C. and 80%. As a result, a good image was obtained in the initial stage, but fogging occurred and a good image was not obtained on the 10000th sheet. As a result of measuring the change in residual potential, it was higher than in the initial stage.

Comparative Example 5 Comparative Example 5 was the same as Example 5 except that the heat treatment step was not performed in the purification process of the fluorine-based comb-type graft polymer of Example 5 and the re-precipitation purification was performed only three times. An electrophotographic photoreceptor was prepared in exactly the same manner.

This electrophotographic photosensitive member was subjected to a process of charging, exposure and strong exposure in an electrophotographic photosensitive member tester (manufactured by Kawaguchi Electric Co., Ltd.) under high temperature and high humidity of 35 ° C. and 80%.
The change in residual potential was measured 10,000 times repeatedly in a 5-second cycle, and the results are shown in Table 1.

This electrophotographic photosensitive member is charged, exposed, developed,
The copying and repeating the transfer and cleaning processes were repeated every 0.5 second, and the copying machine was mounted, and 10,000 copies were continuously made under a high temperature and high humidity condition of 35 ° C. and 80%. As a result, a good image was obtained in the initial stage, but fogging occurred and a good image was not obtained on the 10000th sheet. As a result of measuring the change in residual potential, it was higher than in the initial stage.

Comparative Example 6 1200 parts by weight of the same styryl compound as in Example 1 1014 parts by weight of a polycarbonate resin were dissolved in 5000 parts by weight of monochlorobenzene and 3000 parts by weight of dichloromethane to prepare a coating liquid for a charge transport layer. This liquid was applied by dipping the coating material for the charge transport layer onto an aluminum cylinder on which the charge generation layer had been coated as in Example 1, and the coating was performed at 130 ° C.
Dry for 0 minutes. The film thickness of the charge transport layer was 25 μm.

This electrophotographic photosensitive member was subjected to a process of charging, exposure and strong exposure in an electrophotographic photosensitive member tester (manufactured by Kawaguchi Electric Co., Ltd.) under high temperature and high humidity of 35 ° C. and 80%.
The change in residual potential was measured 10,000 times repeatedly in a 5-second cycle, and the results are shown in Table 1.

This electrophotographic photosensitive member is charged, exposed, developed,
The copying and repeating the transfer and cleaning processes were repeated every 0.5 second, and the copying machine was mounted, and 10,000 copies were continuously made under a high temperature and high humidity condition of 35 ° C. and 80%. As a result, a good image was obtained in the initial stage, but on the 10000th sheet, due to insufficient sensitivity, fogging, toner adhesion, and scratches on the photosensitive drum occurred, and a good image was not obtained. As a result of taking out the photosensitive drum and measuring the thickness of the charge transport layer,
It was 9 μm.

[0095]

[Table 1]

Comparing Example 1 with Comparative Example 1, and Comparative Example 6, Example 2 with Comparative Example 2, Example 3 with Comparative Example 3, Example 4 with Comparative Example 4, and Example 5 with Comparative Example 5, The electrophotographic photoreceptor containing the fluorine-based resin particles in the surface layer and the fluorine-based comb-type graft polymer purified by re-precipitation after heat treatment has little increase in residual potential due to repeated charging and exposure, and charging, exposure and development. In addition to the stable electric potential even after repeated transfer and cleaning processes, a high-quality image having no image defects was obtained even in the initial stage and on the 10000th sheet. On the other hand, the mere reprecipitation purification showed an increase in residual potential with repeated use, and image fogging occurred. Further, in the case of not containing the fluorine-based resin particles, problems such as large abrasion of the photosensitive drum, poor cleaning property, and easy scratching occurred, which caused image defects.

[0097]

As is apparent from the above, the electrophotographic photosensitive member of the present invention has durability against abrasion and scratches on the surface due to friction, and also provides stable high-quality images even under high humidity. Can be formed. It also has excellent cleaning properties.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a general transfer type electrophotographic apparatus.

FIG. 2 is a block diagram of a facsimile using the electrophotographic apparatus as a printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging means 3 Exposure part 4 Developing means 5 Transfer means 6 Cleaning means 7 Pre-exposure means

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Tetsuro Kanamaru 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Junichi Kishi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation

Claims (4)

[Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the surface layer of the photosensitive member comprises fluorine-based resin particles and a fluorine-based comb-type graft polymer purified by reprecipitation after heat treatment. An electrophotographic photoreceptor containing the same. 2. The fluororesin particles are tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodichloroethylene resin, And the electrophotographic photosensitive member according to claim 1, which comprises one or more resins selected from these copolymers. 3. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer has a charge generation layer and a charge transport layer. 4. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1.