JPH05119503A - Electrophotographic sensitive body, electrophotographic device and facsimile equipment provided with the same - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body having high durability, causing no image defect and also having excellent image density reproducibility. CONSTITUTION:This electrophotographic sensitive body has a photosensitive layer and a protective layer on the electric conductive substrate, the protective layer is a film formed by applying and curing a soln. contg. a photosetting acrylic monomer and the thickness of the photo-sensitive layer is <=10mum. Since this sensitive body has excellent image density reproducibility and high wear and scratch resistance of the surface, even in the case of <=10mum thickness of the photosensitive layer, image defects are not caused after repeated electrophotographic processes and a high grade image can stably be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor, particularly an electrophotographic photoreceptor having a surface protective layer.

The present invention also relates to an electrophotographic apparatus and a facsimile having the above electrophotographic photosensitive member.

[0003]

2. Description of the Related Art An electrophotographic photosensitive member is required to have required sensitivity, electric characteristics and optical characteristics according to an electrophotographic process applied thereto. For example, the surface layer of the photoreceptor, that is, the layer that is most isolated from the support, is directly subjected to electrical and mechanical external forces such as corona charging, toner development, transfer to paper, and cleaning treatment. Durability is required. Specifically, it is required to have durability against friction and scratches on the surface due to rubbing, and deterioration of the surface due to ozone generated during corona charging. On the other hand, there is a problem that the toner adheres to the surface layer due to the repeated development and cleaning of the toner, and it is required to improve the cleaning property of the surface layer.

Conventionally, as an electrophotographic photoreceptor, an inorganic photoreceptor having a photosensitive layer containing selenium, zinc oxide, cadmium and the like as a main component has been widely used. Although these have some basic characteristics, they have problems such as difficulty in film formation, poor plasticity, and high manufacturing cost. Further, the inorganic photoconductive material is generally highly toxic, and there are great restrictions in manufacturing and handling.

On the other hand, an organic photoconductor containing an organic photoconductive compound as a main component has many advantages such as supplementing the above-mentioned drawbacks of the inorganic photoconductor and has been attracting attention in recent years. Many proposals have been made so far. It has been put to practical use.

As such an organic photoreceptor, poly-N is used.
An electrophotographic photoreceptor containing a charge transfer complex formed from a photoconductive polymer represented by vinylcarbazole and a Lewis acid such as 2,4,7-trinitro-9-fluorenone as a main component has been proposed. There is. These organic photoconductive polymers are superior to the inorganic photoconductive polymers in terms of light weight, film forming property, etc., but in terms of sensitivity, durability, stability due to environmental changes, etc., the inorganic photoconductive material is used. It was inferior to the above and was not always satisfactory.

On the other hand, a function-separated type electrophotographic photosensitive member in which a charge generating function and a charge transporting function are shared by different substances brings about improvement in sensitivity and durability, which have been the drawbacks of conventional organic photosensitive members. It was Such a function-separated type photoreceptor has an advantage that the material selection range of each of the charge generation material and the charge transport material is wide, and an electrophotographic photoreceptor having arbitrary characteristics can be relatively easily manufactured.

However, when the organic photoconductor is compared with the inorganic photoconductors such as selenium and cadmium, there are still some points inferior in electrical properties. For example, the charge transfer rate in the charge transport material is not sufficient, and the photocharge generation efficiency in the charge generation material and the charge injection efficiency from the charge generation material to the charge transport material depend largely on the electric field. Therefore, in a photographic process in which charging-exposure is repeated, the sensitivity of the photoconductor differs depending on the potential, and the relationship between the amount of light irradiated to the photoconductor and the surface potential of the photoconductor is not linear, and the tail is drawn especially on the low potential side. As a result, the linearity of the developing density of the toner is lost, and as a result, the density reproducibility of the copy is deteriorated.

There is also a drawback that the charge transfer rate is not sufficient and the temperature dependence of the sensitivity is large because the charge transfer rate becomes slower at low temperature.

Further, the organic photoconductive material is inferior in chemical stability to the inorganic material, and the material deteriorates due to repeated electrophotographic processes, resulting in a decrease in sensitivity and an increase in residual potential. was there.

Another drawback of the organic photoconductive material is that it has a low hardness. When it is used as the surface layer of an electrophotographic photoreceptor, it is durable due to abrasion due to rubbing and scratches. Poorness was also a problem. In addition, in the case of an organic photoreceptor having a drawback of being easily scraped, it was necessary to increase the film thickness of the charge transport layer serving as a surface layer in order to increase the durability against repeated electrophotographic processes. As a result, defects of electrical characteristics such as low density reproducibility of copy on the photoconductor, low potential stability, and large temperature dependency of sensitivity are increased.

Next, an attempt has been made to provide a surface protective layer containing a resin as a main component on the photosensitive layer in order to satisfy the characteristics such as mechanical and chemical durability required for the photosensitive member and further the cleaning property. For example, as proposed in JP-A-57-207258, JP-A-53-103741 and the like, a protective layer containing a curable resin as a main component is used to improve hardness and abrasion resistance.

In addition to the surface properties such as high hardness and abrasion resistance, the characteristics required for the protective layer of the photoreceptor are important control of the resistance of the protective layer itself. That is, when the resistance of the protective layer is too high, charge is accumulated in the protective layer itself in the electrophotographic process of repeating charging-exposure.
The so-called residual potential increases, and the potential becomes unstable during repeated use of the photoconductor, and the image becomes unstable. If the resistance is too low, the electrostatic latent image flows in the protective layer in the surface direction, causing problems such as image blurring and blurring.

In order to solve these problems, for example, as proposed in Japanese Patent Laid-Open No. 57-30843, a protective layer has been proposed in which a metal oxide is added as conductive fine particles to control the resistance. However, the conventionally used method has low hardness and abrasion resistance of the resin and has a problem of durability. Further, when the metal oxide particles are dispersed, dispersibility in the binder resin, cohesiveness and protective layer When used, there was a problem in conductivity, and the phenomenon such as non-uniformity of the surface of the protective layer, image defects due to unevenness, increase in residual potential due to repeated charging-exposure, or decrease in image density due to decrease in sensitivity was likely to occur.

[0015]

SUMMARY OF THE INVENTION The present invention is intended to improve the above-mentioned drawbacks of the conventional electrophotographic photoreceptors.
An object of the present invention is to provide an electrophotographic photoreceptor having high durability, no image defects, and good density reproducibility in a wide temperature range.

Still another object of the present invention is to provide an electrophotographic photosensitive member which does not accumulate residual potential in repeated electrophotographic processes and can maintain high quality image.

[0017]

According to the present invention, in an electrophotographic photoreceptor having a photosensitive layer and a protective layer on a conductive support, the protective layer is a film obtained by curing a liquid containing a photocurable acrylic monomer. And the thickness of the photosensitive layer is 10
Provided is an electrophotographic photosensitive member having a thickness of not more than μm.

The details of the present invention will be described below.

The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having a structure in which a photosensitive layer and a protective layer are accumulated in this order on a conductive support. The photosensitive layer will be described below first.

The photosensitive layer of the electrophotographic photosensitive member of the present invention has a single-layer structure containing both the charge generating material and the charge transporting material, or the charge transporting layer and the charge generating layer are accumulated on a conductive support. One of the laminated types is used.

The laminated photosensitive layer will be described below.
The structure of the laminated type photosensitive layer includes one in which a charge generation layer and a charge transport layer are laminated in this order on a conductive support, and one in which a conductive support, a charge transport layer and a charge generation layer are accumulated in this order. ..

The support used in the present invention may be any support as long as it has conductivity, for example, a metal such as aluminum, chromium, nickel, stainless steel, copper or zinc is formed into a drum or sheet, A metal foil such as aluminum or copper laminated on a plastic film, aluminum, indium oxide, tin oxide, etc. deposited on a plastic film, or a conductive material applied alone or with an appropriate binder resin to form a conductive layer. The provided metal, plastic film, paper, etc. may be mentioned.

As the conductive substance used for this conductive layer, metal powder such as aluminum, copper, nickel and silver,
Conductive metal oxides such as metal foil and metal fiber, antimony oxide, indium oxide, tin oxide, polypyrrole,
Examples thereof include polymer conductive materials such as polyaniline and polymer electrolytes, carbon black, graphite powder, organic and inorganic electrolytes, and conductive powders whose surfaces are coated with these conductive substances.

Examples of effective charge generating materials used in the present invention include the following substances. These charge generating materials may be used alone or in combination of two or more.

(1) Azo pigments such as monoazo, bisazo and trisazo (2) Phthalocyanine pigments such as metal phthalocyanine and non-metal phthalocyanine (3) Indigo pigments such as indigo and thioindigo (4) Perylene anhydride, perylene Perylene pigments such as acid imides (5) Polycyclic quinone pigments such as anthraquinone and pyrenequinone (6) Squarylium dye (7) Pyrylium salts, thiopyrylium salts (8) Triphenylmethane dye (9) Selenium, amorphous Inorganic substance such as silicon A layer containing a charge generating material, that is, a charge generating layer may be formed by dispersing the above charge generating material in an appropriate binder and coating the same on a conductive support. it can. Also, vapor deposition, sputtering, CVD on a conductive support.
It can also be formed by forming a thin film by a dry method such as.

The binder may be selected from a wide range of binder resins, such as polycarbonate resin,
Polyester resin, polyarylate resin, butyral resin, polystyrene resin, polyvinyl acetal resin, diallyl phthalate resin, acrylic resin, methacrylic resin, vinyl acetate resin, phenol resin, silicone resin,
Examples thereof include polysulfone resin, styrene-butadiene copolymer resin, alkyd resin, epoxy resin, urea resin, vinyl chloride-vinyl acetate copolymer resin, but are not limited thereto. These may be used alone or as a copolymer polymer, or may be used in combination of two or more kinds.

The resin contained in the charge generation layer is 80% by weight or less, preferably 40% by weight or less. The thickness of the charge generation layer is 5 μm or less, especially 0.01 μm to 2 μm.
A thin film layer having a thickness of μm is preferable.

Various sensitizers may be added to the charge generation layer.

The charge transport layer of the multi-layer type photoreceptor used in the present invention has a polycyclic aromatic compound having a structure such as biphenylene, anthracene, pyrene or phenanthrene in the main chain or side chain, indole, carbazole, oxadiazole,
A nitrogen-containing cyclic compound such as hirazoline, a charge transporting material such as a hydrazone compound and a styryl compound can be formed in combination with a suitable binder resin.

Examples of the binder resin used in the charge transporting layer include those used in the charge generating layer, and further include photoconductive polymers such as polyvinylcarbazole and polyvinylanthracene.

The mixing ratio of the binder resin and the charge transport material is preferably 10 to 500 parts by weight of the charge transport material per 100 parts by weight of the binder resin. Furthermore, an antioxidant, an ultraviolet absorber, and a plasticizer may be added to the charge transport layer as needed.

In forming such a charge transport layer, a coating method such as a dip coating method, a spray coating method, a spinner coating method, a roller coating method, a Mayer bar coating method, a blade coating method or the like is used by using an appropriate organic solvent. Can be done using.

Next, the single-layer type photosensitive layer will be described. The single-layer type photosensitive layer is formed by coating a liquid obtained by dissolving and dispersing the charge transport material, the charge generating material, and the resin containing the binder resin on the conductive support.

Here, in the electrophotographic photosensitive member using the organic photoconductive material as described above, the reason is that the charge transfer speed is low, the temperature dependence is large, and the chemical stability of the material is low. As a result, the reproducibility of the image density is not sufficient, and further, the image density changes due to environmental changes and repeated electrophotographic processes.

As a result of various studies by the present inventors, it was found that increasing the electric field per unit film thickness of the photoconductor in the electrophotographic process is effective in solving these problems. For that purpose, the film thickness of the photoconductor is set to 10
It was found that a sufficient effect can be obtained by reducing the thickness to less than μm. Further, when the film thickness is 7 μm or less, the effect is even greater.

However, since the surface hardness of the organic photoreceptor is not sufficient, it is easily worn and scratched by repeating the electrophotographic process. Therefore, considering durability, setting the film thickness of the photosensitive member to 10 μm or less has a practical problem. Therefore, as a result of further studies, the present inventors tried to provide another surface protective layer on the organic photoconductor having a thickness of 10 μm or less.

Next, the protective layer will be described.

In the protective layer of the electrophotographic photosensitive member, it is necessary to suppress the residual potential to such an extent that it does not pose a problem in the electrophotographic process. One means to solve this is to reduce the thickness of the layer, and the other is to control the resistance of the protective layer. Therefore, in the present invention, when the protective layer is composed only of resin, the film thickness needs to be 1.0 μm or less.

Next, when controlling the resistance of the protective layer, a method of controlling the resistance by dispersing metal oxide particles in the binder resin in the protective layer has been tried as a means for controlling the resistance. However, in the conventional photoconductor, the dispersibility of the metal oxide particles is poor and has been a problem.
Generally, when particles are dispersed in a protective layer, the particle size of the particles must be smaller than the wavelength of the incident light, that is, 0.3 μm or less, in order to prevent scattering of the incident light by the dispersed particles. Is. Here, it was more difficult to uniformly disperse fine particles of 0.3 μm or less in the resin.
Next, in the protective layer for the electrophotographic photosensitive member, it is considered that the film thickness is several μm or less from the viewpoint of preventing the residual potential and retaining the image latent image. Sufficient hardness was not obtained against scratches and abrasion. Therefore, as a result of various investigations, we have found that a resin containing a photocurable acrylic monomer as a resin for a protective layer, particularly having three or more functional groups per molecule or having a functional group number of 0. A resin containing 004 mol / g or more of an acrylic monomer is used, and a liquid in which conductive metal oxide fine particles are dispersed is applied onto the photosensitive layer,
Invented a cured protective layer. As a result, a protective layer having a high film hardness, excellent scratch resistance and abrasion resistance, good dispersion of metal oxide fine particles, no uneven resistance, and a transparent protective layer without residual potential was obtained.

As the conductive metal oxide used in the present invention, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide doped with indium oxide, bismuth oxide, tin or the like, tin oxide doped with antimony,
Ultrafine particles such as zirconium oxide can be used.
These metal oxides may be used alone or in combination of two or more. When two or more kinds are mixed, they may be in the form of solid solution or fusion. The content of the metal oxide particles used in the present invention is 5 to 90% by weight, preferably 10 to 90% by weight. When the content of the metal oxide is less than 5% by weight, the resistance value as the protective layer is too high, and when it is more than 90% by weight, the resistance becomes low as the surface layer of the photoconductor and the chargeability is lowered or the pinhole is reduced. Cause of.

In the present invention, additives such as coupling agents and antioxidants may be added to the protective layer for the purpose of improving dispersibility, adhesiveness and weather resistance. Specific examples of the photocurable acrylic monomer as the binder resin used in the present invention include, but are not limited to, the following examples. Commercially available photocurable acrylic monomers can be used. The system monomer may be used alone, or may be used as a mixture with other commercially available resins such as polyester, polycarbonate, polyurethane, acrylic, epoxy, silicone, alkyd, and vinyl chloride-vinyl acetate copolymer resin. The protective layer is formed by applying and curing a solution of a binder resin alone or a solution of metal oxide fine particles dispersed in the binder resin. In the present invention, since a photocurable acrylic resin is used for the protective layer, a photoinitiator is added to the protective layer preparation liquid when forming the protective layer. The amount of the initiator added is 0.1 to 4 with respect to the acrylic resin.
It is 0% by weight, preferably 0.5 to 20% by weight. Specific examples of the main photoinitiator include the following. The thickness of the protective layer in the present invention is 0.1 to 10 μm, preferably 0.5 to 7 μm.

[0042]

[Chemical 1]

[0043]

[Chemical 2]

[0044]

[Chemical 3]

[0045]

[Chemical 4]

[0046]

[Chemical 5]

[0047]

[Chemical 6]

[0048]

[Chemical 7]

[0049]

[Chemical 8] As the coating in the present invention, in addition to spray coating and beam coating, dip coating can be performed by selecting a solvent.

As described above, the electrophotographic photoreceptor of the present invention in which the photosensitive layer has a thickness of 10 μm or less and the protective layer is laminated thereon is far superior in durability to conventional organic photoreceptors, and It is possible to provide an electrophotographic photosensitive member which is excellent in image stability and density reproducibility in each environment, and therefore can always stably obtain a high-quality image.

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

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

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

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

After the image transfer, the surface of the photosensitive member 1 is cleaned by the cleaning means 6 to remove 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 components, such as the above-described photoconductor, developing unit, and cleaning unit, as an apparatus unit, and this unit is configured to be detachable from the apparatus main body. May be. For example, photoconductor 1
The cleaning means 6 and the cleaning means 6 may be integrated into one apparatus unit, and may be detachably configured 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 out and converted into a signal, and scanning of the laser beam or LED array is performed by this signal. Drive or liquid crystal shutter array drive.

When used as a facsimile printer, the optical image exposure L becomes an exposure for printing the 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 via the transmission circuit 13. The data received from the partner station is sent to the printer 19 through the receiving circuit 12. The image memory 16 stores predetermined image data. The printer controller 18 controls the printer 19. 14 is a telephone.

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

The image is received and recorded as described above.

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

[0064]

EXAMPLES The present invention will be described below with reference to examples. In the examples, “part” means “part by weight” and “%” means “% by weight”.

(Example 1) Conductive titanium oxide powder 50 coated with tin oxide containing 10% antimony oxide
Parts, 25 parts of phenolic resin, 20 parts of methyl cellosolve,
5 parts of methanol and 0.002 parts of silicone oil (polydimethylsiloxane polyoxyalkylene copolymer, average molecular weight 3000) were dispersed for 2 hours in a sand mill using φ1 mm glass beads to prepare a conductive layer coating material. Aluminum cylinder (φ30mm × 260m
m) was coated with the above coating by dip coating and dried at 140 ° C. for 30 minutes to form a conductive layer having a film thickness of 20 μm.

Next, 10 parts of alcohol-soluble copolymerized nylon resin (average molecular weight 29000), methoxymethylated 6
30 parts of nylon resin (average molecular weight 32000) was dissolved in a mixed solvent of 260 parts of methanol and 40 parts of butanol. The prepared liquid was applied onto the conductive layer by dip coating to form an undercoat layer having a thickness of 1 μm.

Next, the following structural formula

[0068]

[Chemical 9] 4 parts of disazo pigment, 2 parts of polyvinyl butyral (butyralization ratio 68%, weight average molecular weight 24000) and 34 parts of cyclohexanone were dispersed for 12 hours in a sand mill using φ1 mm glass beads, and then 60 parts of tetrahydrofuran (THF) was added. To prepare a dispersion liquid for the charge generation layer. This dispersion is dip coated on the above intermediate layer,
It was dried at 0 ° C. for 15 minutes to form a charge generation layer having a film thickness of 0.15 μm.

Next, the following structural formula

[0070]

[Chemical 10] Of styryl compound of 10 parts and polycarbonate (weight average molecular weight of 46000) 10 parts of dichloromethane 20 parts,
It is dissolved in a mixed solvent of 40 parts of monochlorobenzene, and this solution is applied onto the above charge generation layer by dip coating, and the solution is heated at 120 ° C for 6
It was dried for 0 minutes to form a charge transport layer having a film thickness of 7 μm.

Next, the exemplified acrylic monomer (6) 6
0 part, 30 parts of tin oxide ultrafine particles having an average particle size before dispersion of 400Å, 2-methylthioxanthone as a photoinitiator
1 part and 300 parts of toluene were mixed and dispersed in a sand mill for 48 hours.

A film was formed on the above charge transport layer by the beam coating method using this prepared solution, and after drying,
A high pressure mercury lamp was used to perform photocuring for 20 seconds at a light intensity of 8 mW / cm ² to obtain a protective layer. At this time, the thickness of the protective layer is 2μ
It was m. The dispersibility of the protective layer preparation liquid was good, and the surface of the protective layer was a uniform and even surface.

The dependence of the electric potential after charging and exposure on the exposure amount in the electrophotographic photosensitive member thus manufactured is as shown in FIG. In FIG. 3, the photosensitive layer thickness of Comparative Example 1 is 20 μm.
The dependence of the electric potential on the exposure amount of the photoconductor was also shown. It can be seen from FIG. 3 that the surface potential-exposure amount relationship of the photoconductor of Example 1 is much more linear than that of Comparative Example 1, and therefore the toner density reproducibility of the image is excellent.

Next, the photoconductor of Example 1 was attached to a copying machine in which the process of charging-exposure-developing-transfer-cleaning was repeated every 1.5 seconds, and the electrophotographic characteristics were evaluated under normal temperature and normal humidity. Repeated image output durability of 100
The image was evaluated 00 times and evaluated for initial and durability images.

The results are shown in Table 1, which is superior in image density reproducibility from the initial stage of durability as compared with the photoreceptor of Comparative Example 1 having no protective layer and having a photosensitive layer thickness of 20 μm. After that, a large change was made, while Example 1
Almost no change was seen in.

As the evaluation of the image density reproducibility, the density measured value by the Macbeth densitometer (RD914) was 1.0, 0.
The densities of the copy images of three types of charts of 5, 0.3 were measured, and the reproducibility of the density was evaluated.

Example 2 A photoconductor was prepared in the same manner as in Example 1 except that the above-exemplified monomer (21) was used as the acrylic monomer in the protective layer of Example 1, and the concentrations at initial and durability were similarly set. The reproducibility was evaluated. The evaluation results are shown in Table 1.

(Example 3) In Example 1, a protective layer was applied by spray coating a liquid containing 10 parts of the exemplified acrylic monomer (21) and 40 parts of methoxypropanol, and then a high pressure mercury lamp of 8 mW / cm ^{2 was applied.} Light intensity of 3
A photoconductor was prepared in the same manner as in Example 1 except that the film having a thickness of 0.8 μm was formed by performing photocuring for 0 seconds.
An evaluation was done. The evaluation results are shown in Table 1.

Example 4 A conductive layer and an undercoat layer were provided on an aluminum cylinder in the same manner as in Example 1.

Next, the following structural formula

[0081]

[Chemical 11] 10 parts of the charge-transporting material and 10 parts of polycarbonate (weight average molecular weight 25,000) are dissolved in a mixed solvent of 20 parts of dichloromethane and 40 parts of monochlorobenzene, and this solution is dip-coated on the undercoat layer and the temperature is adjusted to 60 ° C. at 120 ° C. After drying for a minute, a charge transport layer having a film thickness of 9 μm was formed.

Next, the following structural formula

[0083]

[Chemical 12] 4 parts of disazo pigment, 2 parts of polyvinyl benzal (80% benzalization rate, weight average molecular weight of 11,000), and 30 parts of cyclohexanone were dispersed for 20 hours in a sand mill using φ1 mm glass beads, and then 60 parts of methyl ethyl ketone was added. A dispersion liquid for the charge generation layer was prepared.
This dispersion is spray coated on the charge transport layer to give 80
The film was dried at 0 ° C. for 15 minutes to form a charge generation layer having a film thickness of 0.10 μm.

Next, the exemplified acrylic monomer (21)
60 parts, tin oxide particles 40 parts, benzophenone as a photoinitiator 1.5 parts and toluene 300 parts were mixed and dispersed in a sand mill for 24 hours. A film was formed on the above charge generation layer by the beam coating method using this prepared solution, dried to remove the solvent, and then 8 mW / cm ^{2 with} a high pressure mercury lamp.
Photocuring was performed for 30 seconds with the light intensity of. The thickness of the protective layer formed at this time was 3.0 μm.

The electrophotographic photosensitive member thus manufactured was attached to a reversal development type laser printer in which the processes of charging, laser, exposure, development, transfer, and cleaning were repeated in a cycle of 1.5 seconds, and electrophotography was performed at room temperature and normal humidity. The characteristics were evaluated, and the image reproduction durability was further repeated 10,000 times. Similarly, the density reproducibility and stability were evaluated.
The results are shown in Table 1.

Example 5 In Example 4, the charge transport material in the charge transport layer was the following structural formula.

[0087]

[Chemical 13] In the same manner as in Example 4, except that the charge transport layer has a thickness of 5 μm, the photosensitive member was manufactured and evaluated. The evaluation results are shown in Table 1.

Comparative Example 1 A protective layer was not formed in Example 1, and the thickness of the charge transport layer was 20 μm.
A photoconductor was prepared in the same manner as in Example 1 and evaluated in the same manner as in Example 1. As a result, as shown in Table 1, the density reproducibility was not perfect from the initial stage, and the density change during durability was large.

(Comparative Example 2) A photosensitive member was prepared in the same manner as in Example 1 except that the protective layer was not formed in Example 1 and evaluated in the same manner as in Example 1. As a result, as shown in Table 1, the density reproducibility at the initial stage was good, but the density change during the durability was large, and image defects due to image fogging and scratches began to occur after the durability of 2000 sheets.

Comparative Example 3 A photoconductor was prepared in the same manner as in Example 4 except that the protective layer was not formed in Example 4 and the thickness of the charge transport layer was 20 μm. An evaluation was done. As a result, as shown in Table 1, the density reproducibility was not perfect from the beginning, and after the durability 500 sheets were scraped, image defects due to scratches began to occur.

[0091]

[Table 1]

[0092]

The electrophotographic photoreceptor of the present invention has a laminated structure of a photosensitive layer / protective layer, and the thickness of the photosensitive layer is 10 μm or less. By setting the film thickness of the photosensitive layer to 10 μm or less, the relationship between the irradiation light amount and the potential becomes more linear, and therefore the image density reproducibility is excellent.

Further, by providing a protective layer on the surface,
Surface abrasion resistance and scratch resistance are improved, and photosensitive layer film thickness is 10μ
It became possible to supply a stable image after repeated durability even at m or less.

[Brief description of drawings]

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

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

FIG. 3 is a graph showing exposure dose dependency of potential after charging-exposure in Example 1 and Comparative Example 1.

[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

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

Claims (6)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer and a protective layer on a conductive support, wherein the protective layer is a film obtained by curing a liquid containing a photocurable acrylic monomer, and An electrophotographic photoreceptor having a film thickness of 10 μm or less. 2. The electrophotographic photosensitive member according to claim 1, wherein the protective layer is a film obtained by curing a liquid in which conductive metal oxide fine particles are dispersed in a liquid containing the photocurable acrylic monomer. 3. The electrophotographic photosensitive member according to claim 1, wherein the number of functional groups of the photocurable acrylic monomer is 3 or more per molecule. 4. The electrophotographic photosensitive member according to claim 1, wherein the number of functional groups of the photocurable acrylic monomer is 0.004 mol / g or more. 5. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1. 6. A facsimile comprising the electrophotographic photosensitive member according to claim 1 and a receiving unit for receiving image information from a remote terminal.