JPH07295271A - Electrophotographic photoreceptor and electrophotographic device - Google Patents

Abstract

PURPOSE:To lower the friction coefft. of the surface layer of a photoreceptor, to provide the surface layer with cleanability and durability and to prevent deterioration of image quality by repetitive use by incorporating fluororesin particles subjected to a heat treatment and a fluorine comb-type graft polymer into the surface layer. CONSTITUTION:The surface layer of the photoreceptor 1 contains the fluororesin particles subjected to the heat treatment and the fluorine comb-type graft polymer. The heat treatment temp. is a temp. above the glass transition temp. of the fluororesin particles and a temp. at which the fluororesin particles are not thermally decomposed. The fluorine comb-type graft polymer is obtd. by copolymerizing a macromonomer consisting of an oligomer of a relatively low mol.wt. having polymerizable functional groups at one terminal of respective molecular chains and a fluorine polymerizable monomer. One or >=2 kinds of polymerizable monomers contg. fluorine atoms at side chains are used for the fluorine polymerizable monomer. These monomers are not particularly limited.

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 photosensitive member that has little deterioration in image quality due to repeated use and is excellent in durability, and an electrophotographic apparatus including the same.

[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, and deterioration of the surface under high humidity. 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, the means of providing the surface with the resin layer in which the fluorine-based resin particles are dispersed 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 fluororesin particles, there is a problem in dispersibility and cohesiveness, it is difficult to form a uniform and smooth film, and the obtained surface layer has image defects such as image unevenness and pinholes. It was unavoidable to have. Also,
In most cases, binder resins and dispersion aids having good dispersibility have deteriorated electrophotographic characteristics, and no effective ones have been found. When a fluorine-type comb-type graft polymer is used as the dispersion aid, the dispersibility of the fluorine-based resin particles is good, but there is a problem that image quality deteriorates due to repeated use under high humidity. That is, the residual potential increased due to repeated use, and fogging occurred on the image. 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 no sufficiently improved method has been obtained.

[0003]

SUMMARY OF THE INVENTION The present invention is intended to provide an electrophotographic photosensitive member and an electrophotographic apparatus having the same which meet 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 of the present invention is to provide an electrophotographic photosensitive member and an electrophotographic apparatus having the same.

[0004]

That is, the present invention provides an electrophotographic photosensitive member having a photosensitive layer on a conductive support, in which the surface layer of the photosensitive member is heat-treated with fluorine-based resin particles, and a fluorine-based comb. An electrophotographic photoreceptor containing a type graft polymer, and an electrophotographic apparatus having the same.

The present invention will be described in detail below.

Examples of the heat treatment method for the fluorine-containing resin particles include a warm air dryer, a vacuum dryer, an electric furnace, an infrared heating furnace,
A far-infrared heating furnace etc. are mentioned.

The heat treatment temperature must be at least the Tg (glass transition temperature) of the fluororesin particles and at a temperature at which the fluororesin particles do not thermally decompose. Specifically, 14
0-280 degreeC is preferable, Especially preferably, it is 160-26.
It is 0 ° C.

When the heating temperature is 150 ° C. or lower, the crystallinity cannot be lowered even by the heat treatment for a long time, and it becomes difficult to improve the dispersibility.

The fluorine-based comb-type graft polymer used in the present invention comprises a macromonomer consisting 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 polymer of a macromonomer is hung in a plate shape on a fluorine-based polymerizable trunk. As the macromonomer, one having an affinity with the resin to which the graft monomer is added is selected, and for example, a polymer or copolymer of acrylic acid ester, methacrylic acid ester, styrene compound or the like is 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.

[0011]

[Chemical 1] [In the formula, R ₁ represents a hydrogen atom or a methyl group. R ₂ is a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group,
It represents a nitrile group and may be a combination of several kinds. 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-based comb-type graft monomer is preferably 5 to 90% by weight, and more preferably 10 to 70% by weight in the fluorine-based comb-type graft monomer. If the content of the fluorine-based monomer residue is less than 5% by weight, the effect of modifying the hydrophobic property cannot be sufficiently exerted,
Further, if the content of the fluorine-based monomer residue exceeds 90% by weight, the solubility with the macromonomer becomes poor.

The fluororesin particles used in the present invention include tetrafluoroethylene resin, trifluoroethylene resin, 6
It is desirable to appropriately select one kind or two or more kinds from a propylene fluoride resin, a vinyl fluoride resin, a vinylidene fluoride resin, a difluorodichloroethylene resin and a copolymer thereof. Ethylene resin and vinylidene fluoride resin are preferred. 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 particle group and prevents aggregation during the formation of a coating film, so that an extremely 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 pump out onto the surface layer. Furthermore, 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 becomes present not only on the surface of the coating film but also in the bulk, so that the compatibility problem with the resin Therefore, accumulation of residual charges occurs when the electrophotographic process is repeated. The binder resin for forming the resin layer may be a polymer having a film-forming property, but a polymethacrylic acid ester, from the viewpoint that it has a certain degree of hardness by itself and does not interfere with carrier transportation, Polycarbonate, polyacrylate, polyester, polysulfone and the like are preferable.

As a method for preparing a coating solution for preparing the electrophotographic photosensitive member of the present invention, a method in which a binder resin, a charge transporting substance and the like are simultaneously dispersed with a solvent, fluorine resin particles and a fluorine comb polymer are used. Can be mentioned. Further, a method may be mentioned 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. An electrophotographic photoreceptor coating liquid used in the present invention,
Alternatively, in the preparation of the fluororesin particle dispersion, 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.

A coating solution for electrophotographic photoreceptor used in the present invention,
Alternatively, as the solvent used for preparing the fluororesin particle dispersion liquid, a solvent having good solubility with respect to the binder resin and the charge transporting substance in the coating liquid, dispersibility with respect to the pigment, and coating property is selected.

Examples of the material of the electroconductive support used in the electrophotographic photosensitive member of the present invention include metals such as aluminum, copper, nickel and silver or alloys thereof; electroconductivity such as antimony oxide, 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.

It is also possible to provide a conductive layer on the support in order to cover the support with defects and protect the support.
For example, metal powders of aluminum, copper, nickel, silver, etc .; conductive metal oxides such as antimony oxide, indium oxide, tin oxide; polymer conductive materials such as polypyrrole, polyanine, polymer electrolytes; carbon fiber, carbon black , Graphite powder; or a conductive substance such as a conductive powder whose surface is coated with a conductive substance, a thermoplastic resin such as an acrylic resin, a polyester resin, a polyamide resin, a polyvinyl acetate resin, a polycarbonate resin, or a polyvinyl butyral resin. ; Polyurethane resin,
Examples thereof include thermosetting resins such as phenolic resins and epoxy resins; those dispersed in a binder resin such as a photocurable resin, and those to which a support is added, if necessary, added on a support.

Further, an intermediate layer may be provided to improve the adhesiveness of the photosensitive layer and the charge injection property from the support. Examples of the intermediate layer material include gelatin, ethylene
Examples of the resin include acrylic acid copolymer, nitrocellulose resin, polyamide resin, polyvinyl alcohol resin, polyvinyl alcohol resin, and the like, which are dissolved in an appropriate solvent and coated on a support. Further, it is possible to add additives as required.

The photosensitive layer may have a single-layer structure or a laminated structure in which the charge-generating layer and the charge-transporting 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. Charge generation substances such as acrylic resin, polyester resin, polyamide resin, polyvinyl acetate resin, polycarbonate resin,
Thermoplastic resins such as polyvinyl butyral resin and polyvinyl bebenzal resin; those dispersed in a binder resin such as thermosetting resin such as polyurethane resin, phenol resin, epoxy resin, etc .; those dispersed in a suitable solvent and applied; Can be mentioned. Further, it is possible to add additives as required.

Examples of the material for the charge transport layer include charge transport substances such as hydrazone compounds, stibene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds and 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; binder resin such as polyurethane resin, phenol resin, epoxy resin or other thermosetting resin, methanol, ethanol, butanol, Alcohols such as isopropyl alcohol; ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone; ethers such as diethyl ether and tetrahydrofuran; acetic acid ether And esters such as propyl acetate; hydrocarbons such as normal hexane, petroleum ether, and toluene; halogenated hydrocarbons such as monochlorobenzene and dichloromethane, etc. dispersed in other suitable solvents, and additives as necessary The thing which applied the thing which added is mentioned. Also, a conductive polymer can be used.

Examples of the coating method used in the present invention include a dip coating method, a spray coating method, a roll coater coating method and a gravure coater coating method.

Fluorine-based resin particles heat-treated according to the present invention,
And the surface area of the photoconductor as a layer containing the fluorine-based comb-type graft polymer (direct toner, and developing device,
It is effective to apply it to a layer that contacts a cleaning device). Examples of the layer structure of the photoreceptor include a photosensitive layer in the case of a single layer structure, a charge transport layer in a laminated photoreceptor in which a charge transport layer is provided on a charge generation layer and functional separation, and a charge generation in 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 constitutional example of a 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 agent P that has been synchronously taken out and fed.

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

After the image transfer, the surface of the photosensitive member 1 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 means 6 may be integrated into one apparatus unit, and the apparatus unit may be detachable by using a guide means such as a rail of the apparatus 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 a laser beam is scanned based on this signal. Or driving an LED array or a liquid crystal shutter array.

When the electrophotographic apparatus of the present invention is used as a printer for a facsimile, the light 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, and then decoded by the CPU 17, and the image memory 16 is sequentially processed. Stored in. 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 photosensitive member of the present invention is used not only in an electrophotographic copying machine, but also in a laser beam printer, C
RT printer, LED printer, liquid crystal printer,
It can be widely used in electrophotographic application fields such as laser plate making.

[0037]

EXAMPLES The present invention will be described in more detail with reference to specific examples. Example 1 2000 parts by weight of conductive titanium oxide coated with tin oxide containing 10% antimony oxide as a conductive layer coating step,
2500 parts by weight of phenolic resin, methyl cellosolve 20
00 parts by weight and 500 parts by weight of methanol were dispersed for 2 hours in a sand mill using φ1 mm glass beads to prepare a conductive layer coating solution.

Aluminum cylinder (φ30 mm × 36
(0 mm, wall thickness 5 mm), after dip-coating the above coating material,
It was dried at 160 ° C. for 25 minutes by a drying device. The thickness of the conductive layer was 20 μm.

Next, as an intermediate layer coating step, N repurified and purified.
Methoxymethylated nylon 6 1000 parts by weight and 6,
250 parts by weight of 12,66,610 copolymer nylon was dissolved in 5000 parts by weight of methanol and 5000 parts by weight of butanol to prepare a coating solution for the intermediate layer. This liquid was further dipped and coated 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 generating layer, 4000 parts by weight of a disazo pigment having the following structural formula,

[0041]

[Chemical 2] 200 parts by weight of polyvinyl butyral resin (butyralization rate 68%, weight average molecular weight 24000) and 5000 parts by weight of cyclohexane are dispersed for 24 hours by a sand mill device using φ1 mm glass beads, and further 5000 parts by weight of tetrahydrofuran are added to apply the charge generation layer. A liquid was prepared. Furthermore, this solution was centrifuged (7000 rpm, 30
Min.) To remove beads and debris. Apply this solution by dip coating on the cylinder coated with the intermediate layer described above, and
Min dried. The film thickness of the charge generation layer was 0.15 μm.

Next, as a heat treatment step of the fluorine-based resin particles, tetrafluoroethylene resin particles (trade name: Lubron L-
2. 200 parts by weight of Daikin Industries, Ltd. was heat-treated in an electric furnace at 260 ° C. for 2 hours.

Next, as a process for preparing a tetrafluoroethylene resin particle dispersion, 100 parts by weight of the tetrafluoroethylene resin particles heat-treated in the above steps, 100 parts by weight of a polycarbonate resin, and a fluorine-type comb-type graft polymer (trade name) : GF-300, manufactured by Toagosei Co., Ltd. (2 parts by weight) and monochlorobenzene (500 parts by weight) were sufficiently mixed, and then dispersed by a sand grinder (made by Imex Co., Ltd.) using glass beads, and tetrafluoroethylene was used. A resin particle dispersion was prepared. At this time, the particle size of the tetrafluoroethylene resin particles in the dispersion was measured by a particle size distribution measuring device (manufactured by Horiba Ltd.), and the results are shown in Table 1.

Next, 200 parts by weight of a styryl compound having the following structural formula

[0045]

[Chemical 3] 800 parts by weight of the polycarbonate resin and 1500 parts by weight of the tetrafluoroethylene resin particle dispersion liquid were dissolved and mixed in 5000 parts by weight of monochlorobenzene and 3000 parts by weight of dichloromethane to prepare a coating liquid for the charge transport layer. 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 thickness of the charge transport layer is 2
It was 5 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 results of measuring changes in residual potential (surface potential after strong exposure) by repeating 10000 times for 5 seconds 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 heat treatment step of polyvinylidene fluoride resin particles,
200 parts by weight of polyvinylidene fluoride resin particles (trade name: DAIEL, manufactured by Daikin Industries, Ltd.) is 160 in an electric furnace.
Heat treatment was performed at ℃ for 7 hours.

Next, in the step of preparing a dispersion liquid of polyvinylidene fluoride resin particles, 100 parts by weight of the polyvinylidene fluoride resin particles heat-treated in the above step, 100 parts by weight of the polycarbonate resin, and a fluorine-type comb-type graft polymer (trade name: After thoroughly mixing 4 parts by weight of GF-150, manufactured by Toagosei Co., Ltd. and 500 parts by weight of monochlorobenzene, dispersed with a sand grinder using glass beads (manufactured by IMEX Co., Ltd.) and tetrafluoroethylene. A resin particle dispersion was prepared. At this time, the particle size of the polyvinylidene fluoride resin particles in the dispersion was measured by a particle size distribution measuring device (manufactured by Horiba, Ltd.), and the results are shown in Table 1.

Using this tetrafluoroethylene resin particle dispersion liquid, a charge transport layer coating liquid 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 with an electrophotographic photosensitive member tester (manufactured by Kawaguchi Denki Co., Ltd.) under high temperature and high humidity of 35 ° C. and 80%.
Table 1 shows the results of measuring changes in the residual potential repeated 10,000 times in a 5-second cycle.

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 heat treatment step for fluorine resin particles, 300 parts by weight of polytrifluoroethylene chloride resin particles (trade name: Daiflon, manufactured by Daikin Industries) were heat treated at 190 ° C. for 5 hours in a vacuum dryer. did.

Next, in the step of producing poly (trifluoroethylene chloride) resin particles, 100 parts by weight of poly (trifluoroethylene chloride) resin particles heat-treated in the above-mentioned step, 100 parts by weight of polycarbonate resin, fluorine-type comb-type graft polymer (Product name: GF-300, manufactured by Toagosei Co., Ltd.) 5
After sufficiently mixing 100 parts by weight of monochlorobenzene and 600 parts by weight of monochlorobenzene, the mixture was dispersed with a sand grinder using glass beads (manufactured by AIMEX Co., Ltd.) to prepare a polytrifluorochloroethylene resin particle dispersion. At this time, the particle size of the polytrifluorochloroethylene resin particles in the dispersion was measured by a particle size distribution measuring device (manufactured by Horiba, Ltd.), and the results are shown in Table 1.

A coating solution for a charge transport layer was prepared in exactly the same manner as in Example 1 using this polytrifluoroethylene chloride resin particle dispersion. 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 25 μm.

This electrophotographic photosensitive member was subjected to a process of charging, exposure and strong exposure in an electrophotographic photosensitive member tester (Kawaguchi Electric Co., Ltd.) under high temperature and high humidity of 35 ° C. and 80%.
Table 1 shows the results of measuring changes in the residual potential repeated 10,000 times in a 5-second cycle.

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 Tetrafluoroethylene resin particles 100 used in Example 1
By weight, 100 parts by weight of a polycarbonate resin, 6 parts by weight of a fluorine-based comb-type graft polymer (trade name: LF-40, manufactured by Soken Chemical Industry Co., Ltd.) and 500 parts by weight of monochlorobenzene were thoroughly mixed, and then glass beads were used. It was dispersed by a sand grinder (manufactured by IMEX Co., Ltd.) to prepare a tetrafluoroethylene resin particle dispersion liquid. At this time, the particle size of the polytetrafluoroethylene resin particles in the dispersion was measured with a particle size distribution measuring device (manufactured by Horiba, Ltd.), and the results are shown in Table 1.

Using this polyvinylidene fluoride resin particle 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 20 μm.

This electrophotographic photosensitive member was subjected to a process of charging, exposure and strong exposure in an electrophotographic photosensitive member tester (Kawaguchi Electric Co., Ltd.) under high temperature and high humidity of 35 ° C. and 80%.
Table 1 shows the results of measuring changes in the residual potential repeated 10,000 times in a 5-second cycle.

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 high-quality image having no image defect was obtained both in the initial stage and on the 10000th sheet.

Example 5 1200 parts by weight of the same styryl compound as in Example 1 and 1000 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 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.

Next, in the process for preparing the tetrafluoroethylene resin particle dispersion liquid, 50 parts by weight of the tetrafluoroethylene resin particles used in Example 1, 100 parts by weight of the polycarbonate resin, and a fluorine-type comb-type graft polymer (trade name) : LF-
40, manufactured by Soken Chemical Co., Ltd.) and 500 parts by weight of monochlorobenzene were thoroughly mixed and dispersed by a sand grinder using glass beads (manufactured by IMEX Co., Ltd.) to disperse tetrafluoroethylene resin particles. A liquid was created.
At this time, the particle size of the polytetrafluoroethylene resin particles in the dispersion was measured with a particle size distribution measuring device (manufactured by Horiba, Ltd.), and the results are shown in Table 1.

Further, this polyfluorinated ethylene resin particle dispersion was spray-coated on the photosensitive drum coated with this charge-transporting 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 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%.
Table 1 shows the results of measuring the change in residual potential by repeating 10,000 times in a 5-second cycle.

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 The same procedure as in Example 1 was carried out except that the tetrafluoroethylene resin particles used in Example 1 were heat treated at 130 ° C. for 10 hours. To produce an electrophotographic photoreceptor.

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%.
Table 1 shows the results of measuring changes in the residual potential repeated 10,000 times in a 5-second cycle.

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, image unevenness had already occurred in the initial stage, and a good image could not be obtained.

Comparative Example 2 An electrophotographic photosensitive member was prepared in the same manner as in Example 2 except that the polyvinylidene fluoride resin powder which was not subjected to the heat treatment in the heat treatment step of the polyvinylidene fluoride resin particles of Example 2 was used. .

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, image unevenness had already occurred in the initial stage, and a good image could not be obtained.

Comparative Example 3 Polyfluorinated ethylene chloride resin particles which were not subjected to heat treatment in the heat treatment step of the poly (trifluorochloroethylene chloride) resin particles of Example 3 were used, and a fluorine-based comb-type graft polymer was used in the dispersion preparation step. An electrophotographic photosensitive member was prepared in exactly the same manner as in Example 3 except that the content was doubled.

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%.
Table 1 shows the results of measuring the change in residual potential by repeating 10,000 times in a 5-second cycle.

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 on the 10000th sheet, and a good image was not obtained.
As a result of measuring the change in residual potential, it was higher than in the initial stage.

Comparative Example 4 Example 4 was repeated except that the heat treatment step was not performed on the tetrafluoroethylene resin particles used in Example 1 but the content of the fluorine-based comb-type graft polymer was doubled. An electrophotographic photoreceptor was prepared in the same manner as in.

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%.
Table 1 shows the results of measuring changes in the residual potential repeated 10,000 times in a 5-second cycle.

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 on the 10000th sheet, and a good image was not obtained. As a result of measuring the change in residual potential, it was higher than in the initial stage.

Comparative Example 5 An electrophotographic photosensitive member was prepared in the same manner as in Example 5, except that the tetrafluoroethylene resin particles used in Example 1 were used without the heat treatment step. .

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%.
Table 1 shows the results of measuring changes in the residual potential repeated 10,000 times in a 5-second cycle.

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, image unevenness occurred in the initial stage, and a good image could not be obtained.

Comparative Example 6 1200 parts by weight of the same styryl compound as in Example 1 and 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 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 Electric Co., Ltd.) at 35 ° C. and 80% high temperature and high humidity.
Table 1 shows the results of measuring the change in residual potential by repeating 10,000 times in a 5-second cycle.

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 lack of sensitivity, fogging, toner adhesion, and scratches on the photosensitive drum, a good image was not obtained.

The photosensitive drum was taken out and the thickness of the charge transport layer was measured. As a result, it was 10 μm.

[0086]

[Table 1] When 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 surface layer was The heat-treated fluorine-based resin particles, and the electrophotographic photoreceptor containing the fluorine-based comb-type graft polymer is excellent in dispersibility of the fluorine-based resin particles, even when the content of the fluorine-type comb-type graft polymer is small, electrification, A high-quality image free from image defects, in which no image fog was observed due to an increase in residual potential, was obtained by repeating the processes of exposure, development, transfer and cleaning.

On the other hand, when the heat treatment is not carried out, the dispersibility of the fluorine-based resin particles is poor, and when the content of the fluorine-based comb-type graft polymer is relatively small, image unevenness occurs in the initial image and the content is compared In the case of a large number of images, the image fog, which is considered to be due to the increase in the residual potential, occurred, and in both cases, a high-quality image without image defects could not be obtained. 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.

[0088]

As is apparent from the above, the electrophotographic photosensitive member of the present invention and the electrophotographic apparatus having the same have durability against abrasion and scratches on the surface due to friction, and also remain at high humidity. A stable high-quality image can be formed without an increase in potential. It also has excellent cleaning properties.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a transfer type electrophotographic apparatus of the present invention.

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 8 Image fixing means

Claims (5)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the surface layer of the photoreceptor contains heat-treated fluorine-based resin particles and fluorine-based comb-type graft polymer. An electrophotographic photosensitive member. 2. The electrophotographic photosensitive member according to claim 1, wherein the temperature of the heat treatment of the fluorine-based resin particles is 140 to 280 ° C. 3. 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. 4. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer has a charge generation layer and a charge transport layer. 5. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1.