JP3118368B2 - Electrophotographic photoreceptor and electrophotographic apparatus provided with the electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member and an electrophotographic apparatus provided with the electrophotographic photosensitive member.

[0002]

2. Description of the Related Art An electrophotographic photoreceptor needs to have sensitivity, electrical characteristics and optical characteristics according to an applied electrophotographic process. Include charging, toner development, transfer to paper,
Since electrical and mechanical external forces are directly applied by processes such as 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 toner adheres to the surface layer due to repetition of development and cleaning by toner, and improvement of the cleaning property of the surface layer is required. Various methods have been studied to satisfy the characteristics required for the surface layer as described above. Among them, means for providing a resin layer in which fluorine-based resin particles are dispersed on the surface is somewhat effective.

[0003] The dispersion of the fluororesin particles has the effect of reducing the coefficient of friction of the surface layer, improving the cleanability, and improving the durability against abrasion and scratches. However, in dispersing the fluororesin particles, there are problems in their dispersibility and cohesion, and it is difficult to form a uniform and smooth film, and the formed surface layer has an image such as image unevenness or pinhole. Having defects was inevitable. In most cases, the use of binder resins, dispersing aids and the like having good dispersibility caused deterioration of electrophotographic characteristics, and no effective one was found. An example of the dispersing aid is a fluorine-based comb-type graft polymer resin. In this case, the dispersion of the fluorine-based resin particles is good, but there is a problem that the image quality is deteriorated by repeated use under high humidity.
That is, the residual potential increased due to repeated use, and image fogging occurred. The cause is that the residual potential rises due to the action of the surfactant contained in the fluorine resin particles, the fluorine comb type graft polymer resin, the organic salts and monomers contained as impurities in the fluorine resin particles, and water. It is in.
For this reason, various purification methods such as reprecipitation and washing have been attempted, but no satisfactory results have been obtained.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the coefficient of friction of a surface layer, to have cleaning properties, durability against abrasion and scratches, and to reduce the residual potential in repeated electrophotographic processes. An object of the present invention is to provide an electrophotographic photosensitive member capable of always obtaining a high-quality image without rising, and an electrophotographic apparatus provided with the electrophotographic photosensitive member.

[0005]

SUMMARY OF THE INVENTION The present invention relates to an electrophotographic photoreceptor having a surface layer containing fluorine-based resin particles and a fluorine-based comb-type graft polymer resin, after passing the surface layer through a narrow nozzle at high pressure. The electrophotographic photoreceptor is characterized by containing a precipitated and purified fluorine comb type graft polymer resin.

According to the principle of the present invention, the fluorine-based comb-type graft polymer resin forms micelles in a solvent, and impurities are taken into the micelles during reprecipitation purification, so that purification cannot be performed sufficiently. However, by passing through a narrow nozzle at high pressure, the formation of micelles is hindered, and impurities are sufficiently purified during reprecipitation purification.

In purifying the fluorine-based comb type graft polymer resin used in the present invention, the fluorine-based comb type graft polymer resin is dissolved in a good solvent, and the solution is passed through a narrow nozzle at high pressure.

As a good solvent for dissolving the fluorine-based comb type graft polymer resin used in the present invention, it is more effective to select a solvent having particularly good solubility in the fluorine-based comb type graft polymer resin. Particularly preferred examples are ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, cyclohexanone, ethers such as diethyl ether and tetrahydrofuran, ethyl acetate,
Examples thereof include esters such as butyl acetate, hydrocarbons such as toluene and benzene, and halogenated hydrocarbons such as chlorobenzene.

FIG. 2 shows an example of the configuration of an apparatus for treating the fluorine-based comb type graft polymer resin solution used in the present invention, which passes through a narrow nozzle at a high pressure. The resin solution is pressurized by a high-pressure pump 11 from a fluorine-based comb-type graft polymerization resin solution tank 10 and guided to a narrow nozzle 12. The processed liquid is received in a resin solution tank (processed) 13.

As an example of the shape of the nozzle, a straight shape may be used, but a nozzle having a crank-shaped bend in the middle of the nozzle of FIG. 3A and a two-time flow of the solution of FIG. A structure in which turbulence is liable to be generated, such as a structure in which the turbulent flow is divided and collided, is preferable.

The size of the nozzle depends on the pressure which requires the capacity of the pump, but is preferably 1000 μm or less.

The pressure applied to the solution is determined by the shape of the nozzle, the type of the fluorine-based comb-type graft polymer resin, and the type of the solvent. Generally, a pressure of 50 kg / cm ² or more, especially 200 kg / cm ² or more gives a good result. Is obtained. The upper limit of the pressure is determined depending on the structure of the apparatus and the range in which the fluorine-based comb type graft polymer resin does not decompose.
If it is more than cm ² , the resin is easily decomposed.

In the present invention, micelles are eliminated by strong turbulence when the fluorine-based comb-type graft polymerization resin solution passes through a narrow nozzle at high speed. Therefore, it is necessary to increase the speed of passing through the nozzle. Preferably 30m /
sec or more, particularly preferably 50 m / sec or more.

With respect to the reprecipitation purification method, a fluorine-based comb-type graft polymerization resin solution passed through a narrow nozzle at a high pressure is mixed with a poor solvent. As the poor solvent for dissolving the fluorine-based comb type graft polymer resin used in the present invention, those having low solubility in the fluorine-based comb type graft polymer resin are suitable. Particularly preferred examples are methanol and ethanol. And alcohols such as toluene, butanol and isopropyl alcohol; hydrocarbons such as normal hexane, petroleum ether and cyclohexane; and water.

It is possible to combine the resin purification method applied in the present invention with other general purification methods such as extraction, ordinary reprecipitation purification and the like.

The fluorine-based comb type graft polymer resin used in the present invention comprises a macromonomer comprising a relatively low molecular weight oligomer having a polymerizable functional group at one end of each molecular chain and having a molecular weight of about 1,000 to 10,000. It is obtained by copolymerizing a fluoropolymerizable monomer, and has a structure in which a macromonomer polymer hangs in a plate shape on the trunk of the fluoropolymer. As the macromonomer, those having an affinity for the resin to which the graft polymerization resin is added are selected. For example, polymers or copolymers of acrylates, methacrylates, styrene compounds and the like are used.

On the other hand, fluorine-based polymerizable monomers include:
One or more polymerizable monomers having a fluorine atom in the side chain as shown in the following (1) to (6) can be used, but the invention is not limited thereto.

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Embedded image 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 may be a combination of several kinds thereof. n is an integer of 1 or more, m is an integer of 1 to 5, k is 1 to
Represents an integer of 4, and m + k = 5.

The content of the fluorine monomer-remaining group in the fluorine-based comb type graft polymer resin is preferably 5 to 90% by weight, and more preferably 10 to 70% by weight in the fluorine-based comb type graft polymer resin.
% By weight is more preferred. When the content of the fluorine-based monomer is less than 5% by weight, the effect of improving the hydrophobicity cannot be sufficiently exerted. On the other hand, when the content of the fluorine-based monomer exceeds 90% by weight, the dissolution with the macromonomer occurs. Worse.

The fluorine-based comb-type graft polymer resin used in the present invention is a resin obtained by graft-polymerizing a macromonomer selected from acrylates, methacrylates and styrene compounds and a perfluoroalkylethyl methacrylate. However, a resin obtained by graft polymerization of perfluoroalkylethyl methacrylate based on methyl methacrylate is particularly preferable.

The fluororesin particles used in the present invention include ethylene tetrafluoride resin, ethylene trifluoride resin, ethylene hexafluoride propylene resin, vinyl fluoride resin, vinylidene fluoride resin and dichlorodichloride. It is desirable to appropriately select one or more of ethylene resins and copolymers thereof, and particularly preferred are tetrafluoroethylene resins and vinylidene fluoride resins. 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 resin improves the dispersibility of the fluorine-based resin particles and prevents aggregation during the formation of a coating film, so that a very uniform and smooth fluorine-based resin particle dispersion layer is formed. You. In addition, since the fluorine-based graft polymer resin has the above-mentioned structure, it has excellent compatibility with a coating solution containing a binder resin for forming a resin layer, and therefore does not migrate or seep onto the surface layer. Furthermore, by using a fluorine-based graft polymer resin which has been passed through a narrow nozzle at high pressure and purified by reprecipitation, there is no accumulation of residual charges due to repeated electrophotographic processes, and stable charging characteristics can be obtained.

The content of the dispersed fluororesin particles is as follows:
From 1 to 50% is suitable, based on the weight of solids, and particularly preferably from 5 to 30%. If the content is less than 1%, the modification effect by dispersion of the fluororesin particle group is not sufficient.
If it exceeds 0%, the light transmissivity decreases, and the mobility of carriers also decreases. The content of the fluorine-based graft polymer resin is suitably from 0.01 to 10% based on the weight of the solid content, and particularly preferably from 0.02 to 2%. Content 0.01
When the amount is less than 10%, the effect of improving the dispersibility of the fluororesin particles is not sufficient. On the other hand, when the amount exceeds 10%, the fluorine-based graft polymer resin is present not only on the surface of the coating film but also in the bulk, so that Due to the compatibility problem, the residual charge accumulates when the electrophotographic process is repeatedly performed.

The binder resin for forming the resin layer may be a polymer having a film-forming property. However, the binder resin may have a certain degree of hardness and may not interfere with carrier transport. Methacrylates, polycarbonates, polyacrylates, polyesters, polysulfones and the like are preferred.

The preparation method of the coating solution for forming the surface layer of the electrophotographic photoreceptor of the present invention comprises the steps of simultaneously preparing a binder resin, a charge transporting substance and the like with a solvent together with fluorine-based resin particles and fluorine-based comb-type graft polymerization resin. It may be dispersed. Alternatively, a dispersion may be prepared by dispersing fluorine-based resin particles, a fluorine-based comb-type graft polymer resin, and a binder resin, and may be mixed with a coating solution in which a charge transporting substance and the like are dispersed in advance. In the preparation of the coating liquid for the electrophotographic photoreceptor or the dispersion of the fluororesin particles, etc., simple stirring and mixing may be used. Used. As the solvent used here, a solvent having good solubility in the binder resin and the charge transport material in the coating liquid and good coatability is selected.

Examples of the conductive support of the electrophotographic photoreceptor of the present invention include metals such as aluminum, copper, nickel and silver or alloys thereof, and conductive metal oxides such as antimony oxide, indium oxide and tin oxide. , Carbon fiber, carbon black, and a mixture of graphite powder and resin.

A conductive layer can be provided on the support for covering defects on the conductive support and protecting the conductive support.
For example, metal powders such as aluminum, copper, nickel, and silver; conductive metal oxides such as antimony oxide, indium oxide, and tin oxide; polymer conductive materials such as polypyrrol, polyaniline, and polymer electrolyte; and carbon Conductive substances such as fiber, carbon black, graphite powder or conductive powder coated on the surface with these conductive substances may be used as acrylic resin, polyester, polyamide, polyvinyl acetate, polycarbonate, polyvinyl butyrate. -A resin dispersed in a binder resin such as a thermoplastic resin such as a thermoplastic resin, a polyurethane, a phenol resin, an epoxy resin, or a photo-curable resin; Examples include those coated on a support.

The photosensitive layer provided on the conductive support may have a single structure or a laminated structure in which functions are separated into a charge generation layer and a charge transport layer.

In the function-separated type photoreceptor, examples of the material for the charge generation layer include azo pigments such as disazo pigments and trisazo pigments, phthalocyanine pigments such as copper phthalocyanine pigment and titanyl phthalocyanine pigment, quinone pigments such as anthrone and perylene pigment. , Charge generation materials such as indigo pigments acrylic resin, polyester, polyamide,
Suitable are those dispersed in a binder resin such as a thermoplastic resin such as polyvinyl acetate, polycarbonate and polyvinyl butyral, and a thermosetting resin such as polyurethane, phenol resin and epoxy resin. Disperse in a suitable solvent to prepare a coating solution. Further, additives can be added as needed.

Examples of the material for the charge transport layer include charge transport materials such as hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds, and acrylic resins. Binders such as thermoplastic resins such as polyester, polyarylate, polyvinyl chloride, polycarbonate, polyvinyl butyral, and polymethacrylate, and thermosetting resins such as polyurethane, phenolic resin, and epoxy resin. The resin may be made of alcohols such as methanol, ethanol, butanol and isopropyl alcohol, ketones such as methyl ethyl ketone, acetone, methyl isopropyl butyl ketone and cyclohexane, ethers such as diethyl ether and tetrahydrofuran. , Ethyl acetate, esters such as propyl acetate, Rumaru hexane, petroleum Est - ether,
Coating solutions such as hydrocarbons such as toluene, halogenated hydrocarbons such as chlorobenzene, dichloromethane and the like, and those dispersed in other appropriate solvents, and those further added with necessary additives, and the like. Those using a polymer are exemplified.

The coating method used in the present invention includes dip coating, spray coating, roll coater coating, and gravure coater coating.

In the present invention, the layer containing the fluorine-based resin particles and the fluorine-based comb-type graft polymer resin which has been purified by reprecipitation after heat treatment is used as the surface layer of the photoreceptor (direct toner).
And a layer in contact with a developing device, a cleaning device, and the like. In the layer configuration of the photoconductor,
In the case of a single-layer photoreceptor, a charge generation layer is provided on the charge transport layer, and on the charge transport layer, a charge generation layer is provided on the charge transport layer. Is used as a conductive layer in a photoreceptor provided with a protective layer, and a protective layer in a photoreceptor provided with a protective layer on the photosensitive layer.

The electrophotographic photosensitive member of the present invention can be applied to a photosensitive drum generally used in an electrophotographic apparatus such as a copying machine, a laser printer, an LED printer, and a liquid crystal shutter printer.

Further, the present invention comprises an electrophotographic apparatus provided with the electrophotographic photoreceptor of the present invention.

FIG. 1 shows a schematic configuration of a general transfer type electrophotographic apparatus using the drum type photosensitive member of the present invention. In the figure, reference numeral 1 denotes a drum type photosensitive member as an image carrier, and a shaft 1
It is rotationally driven at a predetermined peripheral speed in the direction of the arrow around a.
The photoreceptor 1 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by a charging means 2 during the rotation process, and then, in an exposure section 3, a light image exposure L (slit exposure / (Laser beam scanning exposure, etc.). As a result, an electrostatic latent image corresponding to the exposure image is 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 photosensitive member 1 and the transfer means 5 from a paper feeding unit (not shown). Are sequentially transferred onto the surface of the transfer material P fed in synchronization with the transfer. The transfer material P having undergone the image transfer is separated from the photoreceptor surface, introduced into the image fixing means 8 and subjected to image fixing to be printed out as a copy (copy) outside the machine. The surface of the photoreceptor 1 after the image transfer is cleaned and cleaned by removing the transfer residual toner by the cleaning means 6, and is subjected to static elimination by the pre-exposure means 7, and is repeatedly used for image formation. As the uniform charging means 2 for the photoreceptor 1, a corona charging device is generally widely used. Also, the corona transfer means is generally widely used for the transfer device 5. As an electrophotographic apparatus, a plurality of components such as the above-described photoreceptor, developing means, and cleaning means are integrally connected as an apparatus unit, and this unit is detachably attached to the apparatus body. You may comprise. For example, the photoreceptor 1 and the cleaning means 6 may be integrated into one apparatus unit, and may be configured to be detachable using guide means such as rails of the apparatus body. At this time, the above-described 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 uses a reflected light or a transmitted light from the original, or reads the original and converts the signal into a laser. Scanning of the beam,
This is performed by driving a light emitting diode array or a liquid crystal shutter array.

[0035]

【Example】

Example 1 As a conductive layer coating step, 2000 parts (parts by weight, hereinafter the same) of conductive titanium oxide coated with tin oxide containing 10% antimony oxide, 2500 parts of phenol resin, 2000 parts of methyl cellosolve, methanol 500 parts of φ1
The resulting mixture was dispersed in a sand mill using a 2 mm glass bead for 2 hours to prepare a coating solution for a conductive layer. Aluminum cylinder
(Φ30 mm × 360 mm, wall thickness 1 mm) was applied by dip coating, and then dried at 160 ° C. for 25 minutes. The thickness of the conductive layer was 20 μm.

Next, as an intermediate layer coating step, 1000 parts of reprecipitated and purified N-methoxymethylated nylon 6,
250 parts of 12,66,610 copolymerized nylon
The mixture was dissolved in a mixed solvent of 5000 parts of butanol and 5000 parts of butanol to prepare a coating solution for an intermediate layer. After dip coating the coating solution on the conductive layer coated aluminum cylinder,
Dry at 95 ° C. for 7 minutes. The thickness of the intermediate layer is 0.70 μm
And

Next, as a step of coating the charge generation layer, 400 parts of a disazo pigment having the following structural formula:

Embedded image 200 parts of polyvinyl butyral (butyralization ratio 68%, average molecular weight 24000), cyclohexanone 5000
Was dispersed in a sand mill using a φ1 mm glass bead for 24 hours, and 5000 parts of tetrahydrofuran was further added to prepare a coating solution. Further, this solution is centrifuged (7000 r).
pm, 30 minutes) to remove bead residue, dust and the like. The coating solution was applied by dip coating on the aluminum cylinder coated with the intermediate layer, and dried at 85 ° C. for 7 minutes. The thickness of the charge generation layer was 0.15 μm.

Next, as a step of purifying the fluorine-based comb type graft polymer resin, 800 parts (solid content: 25%) of a fluorine-based comb type graft polymer resin (trade name: GF-300, manufactured by Toa Gosei Chemical Co., Ltd.) 500k with the device of the configuration shown in 3
The pressure was increased to g / cm ² , and the mixture was passed through a nozzle having a diameter of 140 μm (the nozzle shape used was the type shown in FIG. 4A). At this time, the passing speed of the solution through the nozzle was 250 m /
sec. This resin solution was dropped into 9000 parts of methanol at a dropping rate of 100 ml / min, and the formed precipitate was separated and recovered from methanol by suction filtration, followed by drying at 50 ° C. for 24 hours using a vacuum dryer. Thus, a purified fluorine-based comb type graft polymer resin was obtained.

Next, as a process for preparing a dispersion of ethylene tetrafluoride resin powder, 100 parts of ethylene tetrafluoride resin powder (trade name: Lubron L-2, manufactured by Daikin Industries, Ltd.) and polycarbonate (Mitsubishi Corporation) After sufficiently mixing 100 parts of Gas Chemical Co., Ltd., 7 parts of a fluorine-based comb graft polymer resin purified in the above step, and 550 parts of chlorobenzene, a high-pressure dispersing machine (trade name: Nanomizer, Nanomizer Co., Ltd.) -) To prepare a dispersion of ethylene tetrafluoride resin powder.

Next, a styryl compound 100 of the following structural formula
0 copies,

Embedded image 800 parts of polycarbonate and 1500 parts of a tetrafluoroethylene resin powder dispersion were dissolved and mixed in 5000 parts of chlorobenzene and 3000 parts of dichloromethane to prepare a charge transport layer coating solution. This coating solution was applied by dip coating on the aluminum cylinder coated with the charge generation layer, and dried at 130 ° C. for 50 minutes. The thickness of the charge transport layer was 25 μm.

The prepared electrophotographic photosensitive member was heated at 35 ° C. and 80%
Under high temperature and high humidity, using an electrophotographic photoreceptor tester (manufactured by Kawaguchi Electric Co., Ltd.), repeating the process of charging, exposing, and strong exposing for 10000 times for 0.5 seconds, and the residual potential (after strong exposing) (Surface potential) was measured. Table 1 shows the results
Shown in

The electrophotographic photosensitive member was charged, exposed, developed,
The transfer and cleaning processes were mounted in a copying machine in which the process was repeated in 0.5 second cycles, and 10,000 copies were continuously made at 35 ° C. and 80% high temperature and high humidity. As a result, a high-quality image free from image defects was obtained both in the initial stage and on the 10,000th sheet.

Example 2 As a step of purifying a fluorine-based comb-type graft polymer resin, 400 parts of a fluorine-based comb-type graft polymer resin (trade name: LF-40, manufactured by Soken Chemical Co., Ltd.) was placed in an apparatus having the structure shown in FIG. (The shape of the nozzle is the type shown in FIG. 3 (b))
The pressure was increased to 200 kg / cm ² , and the solution was passed through a nozzle having a diameter of 80 μm.
0 m / sec). 50 ml / m of this resin solution
at a drop rate of 8000 parts into 8000 parts of methanol,
The resulting precipitate was separated and recovered from methanol by suction filtration, and then dried at 60 ° C. for 24 hours using a vacuum drier to obtain a purified fluorine-based comb type graft polymer resin.

Next, as a preparation step of the tetrafluoroethylene resin powder dispersion, the tetrafluoroethylene resin powder (described above)
After thoroughly mixing 00 parts, 90 parts of polycarbonate, 10 parts of the fluorine-based comb graft resin purified in the above step, and 550 parts of chlorobenzene, the mixture was dispersed using a high-pressure disperser (described above). , An ethylene tetrafluoride resin powder dispersion was prepared.

Using this tetrafluoroethylene resin powder dispersion, a coating solution for a charge transport layer was prepared in exactly the same manner as in Example 1. This coating solution was applied by dip-coating on the same aluminum cylinder coated with the charge generation layer as in Example 1;
Dry for 0 minutes. The thickness of the charge transport layer was 25 μm.

The prepared electrophotographic photosensitive member was heated at 35 ° C. and 80%
Electrophotographic photoreceptor testing machine under high temperature and high humidity
, The process of charging, exposure and strong exposure was repeated 10,000 times in 0.5 second cycles, and the change in residual potential was measured. Table 1 shows the results.

The electrophotographic photosensitive member is charged, exposed, developed,
The transfer and cleaning processes were mounted in a copying machine in which the process was repeated in 0.5 second cycles, and 10,000 copies were continuously made at 35 ° C. and 80% high temperature and high humidity. As a result, a high-quality image free from image defects was obtained both in the initial stage and on the 10,000th sheet.

Example 3 As a step of purifying the fluorine-based comb type graft polymer resin, a fluorine-based comb type graft polymer resin (trade name: GF-150, trade name:
400 parts of Toa Gosei Chemical Co., Ltd.) at 1200 kg / cm
² and passed through a nozzle having a diameter of 80 μm. This resin solution was dropped into 6000 parts of methanol at a dropping rate of 80 ml / min, and the formed precipitate was separated and recovered from methanol by suction filtration, and then dried by a vacuum dryer.
After drying at 24 ° C. for 24 hours, a purified fluorine-based comb type graft polymer resin was obtained.

Next, as a process for preparing a dispersion of poly (ethylene trifluoride) powder, a poly (ethylene trifluoride) powder (trade name: Diflon, manufactured by Daikin Industries, Ltd.)
Parts, 80 parts of polycarbonate, 4 parts of a fluorine-based comb graft resin purified in the above step, and 600 parts of chlorobenzene, and then sufficiently mixed, followed by a dispersing machine using a glass bead (trade name: sand grinder). -, Manufactured by Imex Co., Ltd.) to prepare a polyfluoroethylene chloride powder dispersion.

A coating solution for a charge transport layer was prepared in exactly the same manner as in Example 1 except that this poly (trifluorochloroethylene) powder dispersion was used. This coating solution was dip-coated on the same aluminum cylinder coated with the charge generation layer as in Example 1,
Dry at 30 ° C. for 60 minutes. 25 μm thickness of charge transport layer
m.

The prepared electrophotographic photosensitive member was heated at 35 ° C. and 80%
Electrophotographic photoreceptor testing machine under high temperature and high humidity
, The process of charging, exposure, and strong exposure was repeated 10,000 times for 0.5 seconds in a cycle, and the change in residual potential was measured. Table 1 shows the results.

The electrophotographic photosensitive member was charged, exposed, developed,
The transfer and cleaning processes were mounted in a copying machine in which the process was repeated in 0.5 second cycles, and 10,000 copies were continuously made at 35 ° C. and 80% high temperature and high humidity. As a result, a high-quality image free from image defects was obtained both in the initial stage and on the 10,000th sheet.

Example 4 As a process for preparing a dispersion of polyvinylidene fluoride powder, 100 parts of polyvinylidene fluoride powder, polycarbonate 7
After thoroughly mixing 0 parts, 9 parts of a fluorinated comb-type graft polymer resin purified in the same manner as in Example 1, and 600 parts of chlorobenzene, the mixture was dispersed using a dispersing machine using a glass bead (described above). A polyvinylidene fluoride powder dispersion was prepared.

A coating solution for a charge transport layer was prepared in exactly the same manner as in Example 1, except that this polyvinylidene fluoride powder dispersion was used. This coating solution was applied by dip coating on the same aluminum cylinder coated with the charge generation layer as in Example 1,
Dry at 60 ° C. for 60 minutes. The thickness of the charge transport layer was 20 μm.

The prepared electrophotographic photosensitive member was heated at 35 ° C. and 80%
Electrophotographic photoreceptor testing machine under high temperature and high humidity
, The process of charging, exposure and strong exposure was repeated 10,000 times in 0.5 second cycles, and the change in residual potential was measured. Table 1 shows the results.

The electrophotographic photosensitive member was charged, exposed, developed,
The transfer and cleaning processes were mounted in a copying machine in which the process was repeated in 0.5 second cycles, and 10,000 copies were continuously made at 35 ° C. and 80% high temperature and high humidity. As a result, a high-quality image free from image defects was obtained both in the initial stage and on the 10,000th sheet.

Example 5 1200 parts of the same styryl compound as used in Example 1,
1000 parts of polycarbonate is converted to 5000 parts of chlorobenzene.
Of a charge transporting layer was dissolved in 3,000 parts of dichloromethane and 3000 parts of dichloromethane.

This coating solution was dip-coated on an aluminum cylinder coated with a charge generation layer in the same manner as in Example 1 at 130 ° C.
For 60 minutes. The thickness of the charge transport layer was 20 μm.

Next, as a process for preparing a dispersion of ethylene tetrafluoride resin powder, 50 parts of the same styryl compound as used in Example 1 and ethylene tetrafluoride resin powder (trade name Lubron L-2, Daikin Industries, Ltd.) ) (3 times washing and purification in the same manner as in Example 2), 50 parts of polycarbonate 120
Parts, 4 parts of a fluorinated comb graft resin purified in the same manner as in Example 1, and 500 parts of chlorobenzene were sufficiently mixed, and then a sand grinder using a glass bead was used.
(See above) to prepare a dispersion of ethylene tetrafluoride resin powder. This solution was spray-coated on the photosensitive drum coated with the charge transport layer, and dried at 130 ° C. for 10 minutes to provide a protective layer. The thickness of the protective layer was 4 μm.

The electrophotographic photosensitive member is charged, exposed, developed,
The transfer and cleaning processes were mounted in a copying machine in which the process was repeated in 0.5 second cycles, and 10,000 copies were continuously made at 35 ° C. and 80% high temperature and high humidity. As a result, a high-quality image free from image defects was obtained both in the initial stage and on the 10,000th sheet. Table 1 shows the results.

Comparative Example 1 The procedure of Example 1 was repeated except that the fluorine-based comb polymer was used only for the reprecipitation purification without performing the step of pressurizing the fluorine-based comb polymer and passing it through a nozzle. An electrophotographic photosensitive member was prepared in exactly the same manner as in Example 1.

The prepared electrophotographic photosensitive member was heated at 35 ° C. and 80%
Electrophotographic photoreceptor testing machine under high temperature and high humidity
, The process of charging, exposure and strong exposure was repeated 10,000 times in 0.5 second cycles, and the change in residual potential was measured. Table 1 shows the results.

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

Comparative Example 2 In the step of pressing the fluorine-based comb type graft polymer resin in Example 1 and passing the resin through a nozzle, the pressure applied was 4
An electrophotographic photoreceptor was prepared in exactly the same manner as in Example 1, except that a fluorine-based comb-type graft polymer resin which had been treated at 0 kg / cm ² (the passing speed at this time was 25 m / sec) and purified by reprecipitation was used. It was created.

The prepared electrophotographic photosensitive member was heated at 35 ° C. and 80%
Electrophotographic photoreceptor testing machine under high temperature and high humidity
, The process of charging, exposure and strong exposure was repeated 10,000 times in 0.5 second cycles, and the change in residual potential was measured. Table 1 shows the results.

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

Comparative Example 3 In the purification step of the fluorine-based comb type graft polymer resin in Example 2, except that the step of applying pressure and passing through a nozzle was not performed and the fluorine-based comb type graft polymer resin was used only for reprecipitation purification, An electrophotographic photosensitive member was prepared in exactly the same manner as in Example 2.

The prepared electrophotographic photosensitive member was heated at 35 ° C. and 80%
Electrophotographic photoreceptor testing machine under high temperature and high humidity
, The process of charging, exposure and strong exposure was repeated 10,000 times in 0.5 second cycles, and the change in residual potential was measured. Table 1 shows the results.

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

COMPARATIVE EXAMPLE 4 In the purification step of the fluorine-based comb type graft polymer resin in Example 3, except that the step of applying pressure and passing through a nozzle was not performed, and the fluorine-based comb type graft polymer resin was used only for reprecipitation purification, An electrophotographic photosensitive member was prepared in exactly the same manner as in Example 3.

The prepared electrophotographic photosensitive member was heated at 35 ° C. and 80%
Electrophotographic photoreceptor testing machine under high temperature and high humidity
, The process of charging, exposure and strong exposure was repeated 10,000 times in 0.5 second cycles, and the change in residual potential was measured. Table 1 shows the results.

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

Comparative Example 5 In the purification step of the fluorine-based comb-type graft polymer resin in Example 4, a step of applying pressure and passing through a nozzle was repeated except that the fluorine-based comb-type graft polymer resin was used only for reprecipitation purification twice. An electrophotographic photosensitive member was prepared in exactly the same manner as in Example 4.

The prepared electrophotographic photosensitive member was heated at 35 ° C. and 80%
Electrophotographic photoreceptor testing machine under high temperature and high humidity
, The process of charging, exposure and strong exposure was repeated 10,000 times in 0.5 second cycles, and the change in residual potential was measured. Table 1 shows the results.

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

COMPARATIVE EXAMPLE 6 The procedure of Example 5 was repeated except that the fluorine-based comb type graft polymer resin was used only for reprecipitation purification without pressurizing and passing through a nozzle in the step of purifying the fluorine-based comb type graft polymer resin. An electrophotographic photosensitive member was prepared in exactly the same manner as in Example 5.

The prepared electrophotographic photosensitive member was heated at 35 ° C. and 80%
Electrophotographic photoreceptor testing machine under high temperature and high humidity
, The process of charging, exposure and strong exposure was repeated 10,000 times in 0.5 second cycles, and the change in residual potential was measured. Table 1 shows the results.

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

[0079]

[Table 1]

A comparison of Example 1 with Comparative Example 1, Example 2 with Comparative Example 3, Example 3 with Comparative Example 4, Example 4 with Comparative Example 5, and Example 5 with Comparative Example 6 reveals that the surface layer has fluorine. The electrophotographic photosensitive member containing the fluorine-based comb type graft polymer resin which has been reprecipitated after passing through a narrow nozzle with pressurized resin particles, has a small residual potential increase due to repeated charging and exposure, The potential was stable not only when the processes of exposure, development, transfer and cleaning were repeated, but also a high-quality image free from image defects was obtained at the initial stage and on the 10,000th sheet. On the other hand, in the case of the simple reprecipitation purification and the case where the pressure treatment was insufficient (Comparative Example 2), image fogging in which the residual potential was increased after repeated use occurred.

[0081]

The electrophotographic photoreceptor of the present invention has a remarkable effect that it has durability against abrasion and scratches on the surface due to friction and forms a stable high quality image even in a high humidity environment. To play.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an electrophotographic image forming apparatus using an electrophotographic photosensitive member of the present invention.

FIG. 2 is a schematic configuration diagram of an apparatus that pressurizes a fluorine-based comb-type graft polymerization resin solution of the present invention and passes the solution through a narrow nozzle.

FIG. 3 is a schematic configuration diagram (cross-sectional view) of a nozzle for pressurizing and passing a fluorine-based comb type graft polymerization resin solution of the present invention. (A) Crank type (b) Branch collision type

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Drum type photoreceptor as an image carrier (electrophotographic photoreceptor of the present invention) 1a shaft 2 Corona charging device 3 Exposure unit 4 Developing unit 5 Transfer unit 6 Cleaning unit 7 Pre-exposure unit 8 Image fixing unit 9 Transfer paper L Optical image exposure 10 Resin solution tank (before treatment) 11 Pump 12 Nozzle 13 Resin solution tank (after treatment) 14 Solution inlet 15 Solution outlet

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 5/00-5/16

Claims (4)

(57) [Claims] 1. An electrophotographic photoreceptor containing a fluorine resin particle and a fluorine-based comb-type graft polymer resin in a surface layer thereof. An electrophotographic photoreceptor comprising a type graft polymer resin. 2. The electrophotographic photoreceptor according to claim 1, wherein the fluorine-containing comb-type graft polymer resin contained in the surface layer, which has been passed through a narrow nozzle at a high pressure and then reprecipitated and purified, is made of an acrylate or methacrylic acid. 2. The electrophotographic photoreceptor according to claim 1, comprising a resin obtained by graft polymerization of a macromonomer selected from esters and styrene compounds and perfluoroalkylethyl methacrylate. 3. The electrophotographic photoreceptor according to claim 1, wherein the fluorine resin particles contained in the surface layer are ethylene tetrafluoride resin, ethylene trifluoride chloride resin, ethylene hexafluoride propylene resin, and vinyl fluoride resin. 2. The electrophotographic photoreceptor according to claim 1, comprising a resin selected from the group consisting of vinylidene fluoride resin, ethylene dichloride diethylene resin and copolymers thereof. 4. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1.