JPH08234466A - Electrophotogaphic photoreceptor, process cartridge with the same and electrophotographic device - Google Patents

Abstract

PURPOSE: To stably ensure superior potential characteristics under the condions of a low temp. and humidity through a high temp. and humidity and to successively form images like an initial superior image by incorporating a copolymer having specified structures as repeating units into a middle layer. CONSTITUTION: In the electrophotographic photoreceptor with an electrically conductive substrate, a middle layer on the substrate and a photosensitive layer on the middle layer, a copolymer having two or more kinds of amic acid structures or amic ester structures as repeating units is incorporated into the middle layer. The copolymer may have two or more kinds, in total, of amic acid and amic ester structures. In this case, the copolymer is synthesized using a diamine and carboxylic acid or its deriv.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having an intermediate layer containing a resin having a specific structure. The present invention also relates to a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member as described above.

[0002]

2. Description of the Related Art An electrophotographic photosensitive member usually has a photosensitive layer on a conductive support. However, the photosensitive layer is generally an extremely thin layer, and due to defects on the support surface such as scratches and deposits, There were cases where the film thickness became uneven. This tendency is due to the fact that the current mainstream photosensitive layer is 0.5 μm.
This is particularly noticeable in a so-called function-separated type photosensitive layer having a charge generation layer and a charge transport layer which are extremely thin. When the film thickness of the photosensitive layer is not uniform, potential unevenness and sensitivity unevenness naturally occur, so it is necessary to form the photosensitive layer as uniformly as possible.

An important characteristic required for the electrophotographic photosensitive member is stability of the light potential and the dark potential during repeated use. If these potentials are not stable, the image density will not be stable, or the image will be fogged.

Therefore, the function of covering defects on the surface of the support between the support and the photosensitive layer, improving the adhesiveness between the support and the photosensitive layer, and further preventing injection of carriers from the support to the photosensitive layer. It is proposed to provide an intermediate layer having

Conventionally, as the resin used for this intermediate layer,
Polyamide (JP-A-48-47344 and JP-A-52-25638), polyester (JP-A-52)
-20836 and JP-A-54-26738), polyurethane (JP-A-53-89435 and JP-A-2-115858), quaternary ammonium salt-containing acrylic polymer (JP-A-51). -126149
JP-A-55-103556) and casein (JP-A-55-103556).

However, the electrophotographic photosensitive member using the above-mentioned material as the intermediate layer is liable to change in electric resistance of the intermediate layer in response to changes in temperature and humidity, and is stable in all environments from low temperature and low humidity to high temperature and high humidity. It has been difficult to prepare an electrophotographic photoreceptor having excellent potential characteristics and capable of forming an excellent image.

For example, when the photoreceptor is repeatedly used under low temperature and low humidity where the electric resistance of the intermediate layer tends to increase,
Electric charges tend to remain in the intermediate layer, and the bright portion potential and the residual potential increase. As a result, a copy image may be fogged in the regular development, or the image may be thinned in the reversal development, and thus an image having a predetermined image quality may not be continuously obtained.

On the other hand, under high temperature and high humidity where the electric resistance of the intermediate layer tends to decrease, the barrier function of the intermediate layer decreases, carrier injection from the support tends to increase, and the dark area potential decreases. As a result, the image may be thinned in the regular development, and black dot defects (black spots) and fog may occur in the image in the reversal development.

Further, even if the stability of the potential under low temperature and low humidity and the black dot defect on the image under high temperature and high humidity are improved by providing the intermediate layer, the sensitivity of the photoreceptor itself is often lowered. It was

[0010]

The object of the present invention is to stably exhibit excellent potential characteristics in all environments from low temperature and low humidity to high temperature and high humidity, and to continuously provide excellent images at the initial stage. An object is to provide an electrophotographic photosensitive member that can be formed.

Another object of the present invention is to provide a good image having no defects by interposing an intermediate layer containing a resin having excellent solubility and having an excellent film-forming property between the support and the photosensitive layer. It is to provide an electrophotographic photosensitive member capable of forming a sheet.

A further object of the present invention is to provide a process cartridge and an electrophotographic apparatus having the above electrophotographic photosensitive member.

[0013]

That is, the present invention provides an electrophotographic photoreceptor having a conductive support, an intermediate layer on the conductive support and a photosensitive layer on the intermediate layer, wherein the intermediate layer serves as a repeating unit. An electrophotographic photoreceptor comprising a copolymer having two or more kinds of amic acid structures or amic acid ester structures.

The present invention also provides a process cartridge and an electrophotographic apparatus having the above electrophotographic photosensitive member.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The copolymer used in the present invention is
It may have only a plurality of types of amic acid structures, only a plurality of types of amic acid ester structures, or a total of two or more types of amic acid structures and amic acid ester structures.

With this structure, the solubility of the copolymer can be improved and, as a result, the film-forming property can be improved, so that a good image without defects can be stably obtained. is there. Further, since the solubility is improved, it is possible to use a low boiling point solvent such as an alcohol solvent or an ether solvent, so that deterioration of electrophotographic characteristics due to the solvent remaining in the layer is less likely to occur, and a resin is contained. Even if the intermediate layer of the present invention is formed on the above layer, a smooth layer can be obtained without adversely affecting the lower layer.

The copolymer having an amic acid structure and an amic acid ester structure in the present invention can be synthesized by using a diamine and a carboxylic acid or a carboxylic acid derivative. Examples of such carboxylic acid derivatives include carboxylic acid esters and carboxylic acid anhydrides. The amic acid structure and the amic acid ester structure are represented by the following formula (1).

[0018]

[Outside 4] (In the formula, A represents a tetravalent organic group, B represents a divalent organic group, and R represents a hydrogen atom or an alkyl group.).

In the above formula (1), the tetravalent organic group of A has at least one cyclic group, and preferable examples thereof include the following, but are not limited thereto.

[0020]

[Outside 5]

In the above formula (1), the divalent organic group B has at least a saturated hydrocarbon group, an aromatic hydrocarbon ring group or an aromatic heterocyclic group, and at least one cyclic group. It is preferable to have. Examples include, but are not limited to, the following.

[0022]

[Outside 6]

[0023]

[Outside 7]

In the above formula (1), R includes a hydrogen atom and an alkyl group such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl and tert-butyl.

The number average molecular weight of the copolymer used in the present invention is preferably 500 to 100,000, and particularly preferably 10,000 to 50,000.

In the present invention, the amide moiety of the amic acid and the amide acid ester structure and the acid or the acid ester moiety are dehydrated or dealcoholized depending on the drying conditions in the drying step usually carried out when producing an electrophotographic photoreceptor. The reaction may form an imide structure.

In the present invention, the number of acid structures and acid ester structures is preferably 20 to 80 mol% of the total number of acid structures, ester structures and imide structures of the copolymer, particularly 40 to 60 mol%. Preferably present. The reason is not clear, but the acid or acid ester structure blocks the injection of holes from the conductive support, facilitating the dissociation of carriers generated by the action of the charge generating substance and the injection of electrons into the intermediate layer. In addition to that, the imide structure takes a tight packing to dissociate the carrier,
It is thought that this is because the injection and movement of electrons were made smoother and less affected by moisture.

The amic acid in the copolymer of the present invention
Total number of structures, amic acid ester structures and imide structures
The ratio of the imide structure with respect to (imidization ratio, mol%) is
The infrared absorption spectrum of the sample is measured, and it is unique to the imide group.
1740 to 1780 cm^-1Of absorption of
It can be determined from the absorbance. Also, the sample H ¹ 
-Measure the NMR spectrum and
Obtained by determining the proton content of the acid ester group
Can be

Specific preferred examples of the repeating unit contained in the copolymer used in the present invention are shown below, but the invention is not limited thereto. The repeating unit is represented by the formula (1)
Is represented as a basic type, and is represented by showing A, B, and R, which are changing parts. The numbers in parentheses are the molar ratios of the respective raw materials used when synthesizing the exemplified compounds.

[0030]

[Outside 8]

[0031]

[Outside 9]

[0032]

[Outside 10]

[0033]

[Outside 11]

[0034]

[Outside 12]

[0035]

[Outside 13]

[0036]

[Outside 14]

[0037]

[Outside 15]

[0038]

[Outside 16]

[0039]

[Outside 17]

The copolymer used in the present invention is synthesized, for example, by a ring-opening polyaddition reaction of tetracarboxylic dianhydride or a dicarboxylic acid derivative obtained by half-esterifying the anhydride with a diamine in an organic polar solvent. It Examples of such an organic polar solvent include N, N-dimethylacetamide,
Examples thereof include amide solvents such as N, N-dimethylformamide and N-methylpyrrolidone; phenol solvents such as cresol and chlorophenol; ether solvents such as diethylene glycol dimethyl ether; and mixtures thereof. Further, in order to control the molecular weight of the resin, the reaction can be carried out by adding 5% by weight or less of water to the above organic polar solvent. The reaction temperature is 20
Is preferably 120 to 120 ° C., particularly 20 to 40 ° C.
It is preferred that

The above-mentioned polyimide can be synthesized by heat-treating the above polyamic acid or polyamic acid ester. The treatment temperature is preferably 50 to 400 ° C., and the treatment time is preferably 5 minutes to 4 hours.

The molar ratio of the starting material diamine to the carboxylic acid or carboxylic acid derivative is preferably 1: 1. In the present invention, three or more raw materials are used, but it is preferable that the molar ratio of all diamines to all carboxylic acids or carboxylic acid derivatives is 1: 1. Diamine,
Alternatively, the ratio in the carboxylic acid or the carboxylic acid derivative can be arbitrarily determined, but the most component is 80
It is preferably not more than mol%.

The synthesis examples of the copolymer used in the present invention are shown below. (Synthesis example) 4,6 '-(hexafluoroisopropylidene) diphthalic anhydride 6.66 g (0.015 mol) while sending dry nitrogen gas to a 500 ml four-necked flask.
And 4,4'-biphthalic anhydride 4.41 g (0.015
mol) and 150 g of N, N-dimethylacetamide were added. This solution was vigorously stirred at 25 ° C. and 6.01 g of 4,4′-diaminodiphenyl ether over 1-2 minutes.
(0.030 mol) was added. When the mixture was stirred for 3 hours while continuously feeding nitrogen, the reaction liquid became a viscous pale yellow liquid. 1.51 / 1.5 with vigorous stirring of this reaction solution
The resulting polyamic acid was added dropwise to the water / methanol solution of 1 and the precipitated polyamic acid was collected by filtration. The produced compound was dried and the exemplified compound No.
9.80 g of polyamic acid having 3 repeating units was obtained.

Other copolymers used in the present invention can be synthesized by the same method as described above.

The intermediate layer in the present invention may be composed of only one layer, or may be composed of a plurality of layers and at least one layer thereof contains the resin of the present invention. When the intermediate layer is composed of a plurality of layers, examples of the resin other than the resin of the present invention include polyamide, polyester and phenol resins.

Further, the intermediate layer of the present invention may contain other resins, additives, conductive substances and the like, if necessary, in an amount within the range in which the effects of the present invention can be obtained. Examples of the other resin include polyamide, polyester, and phenol resin, and examples of the additive include acceptor compounds such as 2,5,7-trinitrofluorenone and benzoquinone. Examples of the conductive substance include metal. Powder (for example, aluminum, copper, nickel and silver), metal short fiber, carbon fiber, conductive powder [for example, carbon black, titanium black, graphite, metal oxide and metal sulfide (for example, antimony oxide, indium oxide, Tin oxide, titanium oxide, zinc oxide, potassium titanate, barium titanate, magnesium titanate,
Zinc sulfide, copper sulfide, magnesium oxide, aluminum oxide, etc.), and those metal oxides or metal sulfides surface-treated with a conductive substance, those surface-treated with a silane coupling agent or a titanium coupling agent, and Reduction treatment] and the like.

In any case, the content of the copolymer of the present invention in the intermediate layer of the present invention is preferably 10 to 90% by weight based on the total weight of the contained intermediate layer, and particularly 3
It is preferably from 0 to 70% by weight.

The thickness of the intermediate layer of the present invention can be appropriately set in consideration of electrophotographic characteristics and defects on the support, but it is preferably 0.1 to 50 μm, and particularly 0. It is preferably 0.5 to 30 μm.

The photosensitive layer of the electrophotographic photoreceptor of the present invention comprises a single layer type containing a charge generating substance and a charge transporting substance in the same layer, and a charge generating layer containing the charge generating substance and a charge transporting substance. It is roughly classified into a laminated type having a charge transport layer. The laminated type is further classified into a type having a conductive support, a charge generation layer and a charge transport layer in this order and a type having a conductive support, a charge transport layer and a charge generation layer in this order. In the present invention, a laminated type, particularly a type in which a charge transport layer is laminated on a charge generation layer, is preferable.

The charge generation layer includes azo pigments such as monoazo, bisazo and trisazo; phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine; indigo pigments such as indigo and thioindigo; polycyclic quinone pigments such as anthanthrone and pyrenequinone. Pigments; perylene pigments such as perylene anhydride and perylene imide; squarylium dyes; pyrylium and thiapyrylium salts; and charge generating substances such as triphenylmethane dyes, using a suitable solvent as a binder resin, for example polyvinyl. It can be formed by applying a solution dispersed in a resin such as acetal, polystyrene, polyester, polyvinyl acetate, methacrylic resin, acrylic resin, polyvinylpyrrolidone and cellulosic resin and drying. The thickness of the charge generation layer is usually preferably 5 μm or less, and particularly preferably 0.05 to 2 μm.

The charge transport layer is formed by applying a solution of the following charge transport material to a binder resin solution and drying the solution. Charge transport materials are roughly classified into electron transport materials and hole transport materials. As electron transport material,
2,4,7-trinitrofluorenone, 2,4,5,7
-Electron-accepting substances such as tetranitrofluorenone, chloranil and tetracyanoquinodimethane, and those obtained by polymerizing these. As the hole-transporting substance, polycyclic aromatic compounds such as pyrene and anthracene; heterocyclic compounds such as carbazole, indole, imidazole, oxazole, thiazole, oxadiazole, pyrazole, pyrazoline, thiadiazole and triazole; p-diethylaminobenzaldehyde- Hydrazone compounds such as N, N-diphenylhydrazone and N, N-diphenylhydrazino-3-methylidene-9-ethylcarbazole; α-phenyl-4′-N, N-diaminostilbene and 5- [4- (di -P-tolylamino)
Benzylidene] -5H-dibenzo [a, d] dicycloheptene and other styryl compounds; benzidine compounds;
Triarylamine compounds: polymers having triphenylamine or a group composed of these compounds in the main chain or side chain (for example, poly-N-vinylcarbazole and polyvinylanthracene).

Examples of the binder resin include polyester, polycarbonate, polymethacrylic acid ester and polystyrene.

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

In the case of a single layer type, it can be formed by applying a solution in which the above-mentioned charge generating substance and charge transporting substance are dispersed and dissolved in a binder resin, and drying. At this time, the film thickness is preferably 5 to 40 μm, and particularly preferably 10 to 30 μm.

Further, in the present invention, an organic photoconductive polymer layer such as polyvinylcarbazole or polyvinylanthracene, a vapor deposition layer of the above-mentioned charge generating substance, a selenium vapor deposition layer,
A selenium-tellurium vapor deposition layer, an amorphous silicon layer, etc. can also be used as the photosensitive layer.

Examples of the conductive support used in the present invention include aluminum, aluminum alloys, copper, zinc, stainless steel, titanium, nickel, indium, gold and platinum. In addition, these metals and alloys,
Plastics (eg polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate and acrylic resin) which have been coated by a vacuum deposition method or conductive particles (eg carbon black and silver particles) together with a suitable binder resin as described above. It is possible to use a support coated on a plastic, metal or alloy support, or a support obtained by impregnating plastic or paper with conductive particles. Examples of the shape of the support include a drum shape, a sheet shape, and a belt shape, but it is preferable that the shape is most suitable for the electrophotographic photoreceptor to be applied.

Further, in the present invention, a resin layer or a resin layer containing conductive particles may be laminated as a protective layer on the photosensitive layer.

Examples of the coating method of the various layers described above include a dip coating method, a spray coating method, a beam coating method, a spinner coating method, a roller coating method, a wire bar coating method and a blade coating method.

The electrophotographic photosensitive member of the present invention can be applied to general electrophotographic devices such as copying machines, laser printers, LED printers, liquid crystal shutter type printers, etc., but it is further applicable to displays, recording, light printing, and electrophotographic technology. It can be widely applied to devices such as plate making and facsimile.

FIG. 1 shows a schematic structure of an electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention.

In the figure, reference numeral 1 is a drum-shaped electrophotographic photosensitive member of the present invention, which is rotationally driven around a shaft 2 in the direction of an arrow at a predetermined peripheral speed. The photoconductor 1 rotates during the rotation process.
The peripheral surface of the primary charging means 3 is uniformly charged with a positive or negative predetermined potential, and then image exposure light 4 from an image exposure means (not shown) such as slit exposure or laser beam scanning exposure is received. In this way, electrostatic latent images are sequentially formed on the peripheral surface of the photoconductor 1.

The formed electrostatic latent image is then developed by the developing means 5.
The toner-developed image is developed by the toner, and the developed toner-developed image is taken out from a paper feeding unit (not shown) between the photoconductor 1 and the transfer means 6 in synchronization with the rotation of the photoconductor 1 and fed to the transfer material 7, The images are sequentially transferred by the transfer means 6.

The transfer material 7 which has received the image transfer is separated from the surface of the photoconductor and introduced into the image fixing means 8 to undergo image fixing, and is printed out to the outside of the apparatus as a copy.

The surface of the photoconductor 1 after the image transfer is cleaned by the cleaning means 9 after removal of the transfer residual toner, and the pre-exposure light 10 from the pre-exposure means (not shown).
It is used for repeated image formation after being neutralized by. If the primary charging means 3 is a contact charging means using a charging roller or the like, pre-exposure is not always necessary.

In the present invention, among the constituent elements such as the electrophotographic photosensitive member 1, the primary charging means 3, the developing means 5 and the cleaning means 9 described above, a plurality of components are integrally combined to form a process cartridge, The process cartridge may be detachably attached to an electrophotographic apparatus body such as a copying machine or a laser beam printer. For example, at least one of the primary charging unit 3, the developing unit 5, and the cleaning unit 9 is integrally supported with the photosensitive member 1 to form a cartridge, which can be detachably attached to the apparatus main body by using a guide unit such as a rail 12 of the apparatus main body. It can be the process cartridge 11.

Further, when the electrophotographic apparatus is a copying machine or a printer, the image exposure light 4 is reflected light or transmitted light from the original, or the original is read by a sensor and converted into a signal, which is performed in accordance with this signal. Light emitted by scanning a laser beam, driving an LED array, driving a liquid crystal shutter array, and the like.

On the other hand, when used as a printer for a facsimile, the image exposure light 4 becomes exposure light for printing received data. FIG. 2 is a block diagram showing an example of this case.

The controller 14 controls the image reading section 13 and the printer 22. The entire controller 14 is controlled by the CPU 20. The read data from the image reading unit 13 is transmitted to the partner station through the transmission circuit 16. The data received from the partner station is sent to the printer 22 through the receiving circuit 15. Predetermined image data is stored in the image memory. The printer controller 21 controls the printer 22. 17 is a telephone.

The image received from the line 18 (image information from a remote terminal connected via the line) is demodulated by the receiving circuit 15, and then the image information is decoded by the CPU 20 and sequentially stored in the image memory 19. To be done. When an image of at least one page is stored in the memory 19, the image of that page is recorded.
The image information of one page is read from the image memory 19, and the decoded image information of one page is sent to the printer controller 21. Printer controller 21
When receiving the image information of one page from the CPU 20, controls the printer 22 to record the image information of the page. The CPU 20 is receiving the next page during recording by the printer 22.

In this way, the image is received and recorded.

[0071]

EXAMPLES The present invention will be described in more detail with reference to the following examples. (Example 1) Exemplified Compound No. A copolymer having an amic acid structure of 3 (number average molecular weight of 10, 0
00) 5 parts (parts by weight, the same below) were dissolved in 95 parts of tetrahydrofuran to obtain a liquid, which was applied on an aluminum cylinder (outer diameter 30 mm x length 254 mm) by a dip coating method and left at room temperature for 10 minutes. After doing 16
An intermediate layer having a thickness of 1 μm was formed by heating at 0 ° C. for 30 minutes.

The imidation ratio of the copolymer was found to be 42 mol% from the measurement results of the infrared absorption spectrum of the copolymer obtained by drying the same solution under the same conditions.

Next, the following equation

[0074]

[Outside 18] 4 parts of the oxytitanium phthalocyanine pigment represented by the above is added to a solution of 2 parts of polyvinyl butyral (BX-1, manufactured by Sekisui Chemical Co., Ltd.) dissolved in 34 parts of cyclohexanone, and dispersed in a sand mill for 8 hours, and then 60 parts of tetrahydrofuran. Was further added and diluted to obtain a charge generation layer solution. This solution is applied onto the intermediate layer by dip coating and dried to obtain a film thickness of 0.
A 2 μm charge generation layer was formed.

Then, the following formula

[0076]

[Outside 19] 5 parts of triarylamine and a polycarbonate resin (Iupilon Z-200, Mitsubishi Gas Chemical Co., Inc.)
5 parts of a solution prepared by dissolving 40 parts of monochlorobenzene into the charge generation layer by dip coating.
A charge transport layer having a film thickness of 15 μm was formed by drying for 0 minutes.

The obtained electrophotographic photosensitive member was charged-exposure-
It is attached to a reversal development type laser beam printer that performs the process of development-transfer-cleaning in a cycle of 1.5 seconds, and it continuously outputs 5,000 images under high temperature and high humidity environment (30 ° C, 85% RH). The test was conducted. The evaluation was performed by measuring the dark part potential (V _D ) in the initial stage, measuring the bright part potential (V _L ) in the initial stage and after the durability test, and visually evaluating the obtained image. The results are shown in Table 1.

(Examples 2 to 10) Exemplified compound No. Instead of the copolymer having an amic acid structure of No. 3, exemplified compound No. 4, 8, 12, 15, 20, 21, 2
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the copolymers having the amic acid or amic acid ester structures of 5, 30, and 32 were used. The results are shown in Table 1.

(Comparative Example 1) An alcohol-soluble copolymer nylon (Amilan CM-8000, Toray Industries, Inc.) was used as an intermediate layer.
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that a solution of 5 parts of methanol) was dissolved in 95 parts of methanol. The results are shown in Table 1.

Comparative Example 2 Zirconium tetraacetylacetonate (ZC150, manufactured by Matsumoto Trading Co., Ltd.) was used as the intermediate layer.
Solution of 10 parts of γ-methacryloxypropyltrimethoxysilane (KBM503, manufactured by Shin-Etsu Chemical Co., Ltd.) in a mixed solvent of 400 parts of methanol, 100 parts of n-butanol and 200 parts of n-amyl alcohol. An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the composition was applied and then dried at 155 ° C. for 120 minutes. The results are shown in Table 1.

Comparative Example 3 Exemplified Compound No. The copolymer having an amic acid structure of 3 is represented by the formula

[0082]

[Outside 20] An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the copolymer having an amic acid structure represented by and the tetrahydrofuran was changed to dimethylformamide.
The results are shown in Table 1.

Comparative Example 4 The intermediate layer was dried at 100 ° C. for 6 hours.
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the intermediate layer was formed by performing heat treatment for 0 minutes and further heat treatment at 250 ° C. for 3 hours. As a result of analysis by infrared absorption spectrum, all the amic acid structures in the resin used for the intermediate layer were imidized. The results are shown in Table 1.

[0084]

Example 11 On the aluminum cylinder used in Example 1, resol type phenol resin (Priofen J-325, manufactured by Dainippon Ink and Chemicals, Inc.) 25
Parts, 50 parts of conductive titanium oxide powder coated with tin oxide containing 10% antimony oxide, methyl cellosolve 2
20 parts of a mixture of 5 parts and 5 parts of methanol in a sand mill.
The time-dispersed liquid was applied and dried to form a first intermediate layer having a film thickness of 10 μm. Then, a second intermediate layer was provided on the first intermediate layer in the same manner as in Example 2. However, the film thickness of the second intermediate layer was 0.5 μm. The produced sample was observed with an optical microscope, and it was a smooth coated surface without cracks.

Comparative Examples 5 and 6 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 11 except that the second intermediate layer was formed in the same manner as in Comparative Examples 2 and 3.

After applying the second intermediate layer, cracks which could be seen by visual observation occurred in the first intermediate layer.

(Embodiment 12) Outer diameter 30 mm × length 360
Using an aluminum cylinder of mm, the intermediate layer is dried at 170 ° C. for 10 minutes and the thickness of the intermediate layer is 1.2 μm.
And except that the charge generation layer was formed as follows.
An electrophotographic photoreceptor was prepared in the same manner as in Example 1.

(Formation Method of Charge Generation Layer)

[0090]

[Outside 21] 5 parts of bisazo pigment represented by tetrahydrofuran 90
Parts were added and dispersed by a sand mill for 20 hours. Butyral resin (BLS, Sekisui Chemical Co., Ltd.) 2.5
A solution obtained by dissolving 20 parts of tetrahydrofuran in 20 parts was added, and the mixture was further dispersed for 2 hours. Cyclohexanone 10 was added to this dispersion.
A solution diluted with 0 parts and 80 parts of tetrahydrofuran was applied onto the previously formed intermediate layer by a dip coating method, and dried for 5 minutes to give a film thickness of 0.
A 28 μm charge generation layer was formed.

The obtained electrophotographic photosensitive member was charged-exposure-
The development-transfer-cleaning process was carried out in a cycle of 0.8 seconds and mounted on a regular development type plain paper copier and continuously operated at a low temperature and low humidity environment (15 ° C, 15% RH) for 10,000 times.
A durability test was conducted on 0 images. The evaluation was performed by measuring the dark part potential (V _D ) in the initial stage, measuring the bright part potential (V _L ) in the initial stage and after the durability test, and visually evaluating the obtained image. Table 2 shows the results.

(Examples 13 to 21) Electrophotographic photoreceptors were prepared and evaluated in the same manner as in Example 12 except that the intermediate layer solutions used in Examples 2 to 10 were used. Table 2 shows the results
Shown in

(Comparative Examples 7 to 10) Electrophotographic photosensitive members were prepared and evaluated in the same manner as in Example 12 except that the intermediate layer solutions used in Comparative Examples 1 to 4 were used. Table 2 shows the results.

[0094]

[0095]

As described above, according to the present invention, it has stable and excellent potential characteristics and durability characteristics in all environments from low temperature and low humidity to high temperature and high humidity, and is excellent even after repeated use. An electrophotographic photosensitive member capable of continuously forming an image, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus can be provided.

[Brief description of drawings]

FIG. 1 shows an example of a schematic configuration of an electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention.

FIG. 2 shows an example of a block diagram of a facsimile having the electrophotographic photosensitive member of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Gen Miyazaki, 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (8)

[Claims] 1. An electrophotographic photoreceptor having a conductive support, an intermediate layer on the conductive support, and a photosensitive layer on the intermediate layer, wherein the intermediate layer has two or more amic acid structures as repeating units or An electrophotographic photoreceptor comprising a copolymer having an amic acid ester structure. 2. An amic acid structure and an amic acid ester structure are represented by the following formula (1): (In the formula, A represents a tetravalent organic group, B represents a divalent organic group, and R represents a hydrogen atom or an alkyl group.) The electrophotographic photosensitive member according to claim 1. 3. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer has a charge generation layer and a charge transport layer. 4. The electrophotographic photosensitive member according to claim 3, wherein the electrophotographic photosensitive member has a conductive support, an intermediate layer, a charge generating layer and a charge transporting layer in this order. 5. A process cartridge having an electrophotographic photosensitive member and at least one unit selected from the group consisting of a charging unit, a developing unit and a cleaning unit, wherein the electrophotographic photosensitive member is a conductive support and the conductive support. An intermediate layer on the body and a photosensitive layer on the intermediate layer, wherein the intermediate layer contains as a repeating unit a copolymer having two or more kinds of amic acid structures or amic acid ester structures, and the electrophotographic photoreceptor , And the at least one means are integrally supported and detachable from the main body of the electrophotographic apparatus. 6. An amic acid structure and an amic acid ester structure have the following formula (1): 6. The process cartridge according to claim 5, wherein A represents a tetravalent organic group, B represents a divalent organic group, and R represents a hydrogen atom or an alkyl group. 7. An electrophotographic photoreceptor, a charging means, an exposing means,
In an electrophotographic apparatus having a developing means and a transferring means, the electrophotographic photoreceptor has a conductive support, an intermediate layer on the conductive support and a photosensitive layer on the intermediate layer, and the intermediate layer is a repeating unit. An electrophotographic apparatus containing as a copolymer a copolymer having two or more kinds of amic acid structures or amic acid ester structures. 8. An amic acid structure and an amic acid ester structure are represented by the following formula (1): (In the formula, A represents a tetravalent organic group, B represents a divalent organic group, and R represents a hydrogen atom or an alkyl group.) The electrophotographic apparatus according to claim 7.