JP3262488B2 - Electrophotographic photoreceptor, electrophotographic apparatus and apparatus unit using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic photosensitive member, and more particularly, to an electrophotographic photosensitive member having excellent surface hardness and abrasion resistance. Further, the present invention relates to an electrophotographic apparatus and an apparatus unit having the above electrophotographic photosensitive member.

[0002]

2. Description of the Related Art An electrophotographic photosensitive member is a main medium for forming an image in an electrophotographic process such as a copying machine, a laser beam printer, and a facsimile. The image forming process is usually a repetition of charging, exposure, development, transfer, cleaning and charge removal. More specifically, when an electrophotographic photosensitive member whose surface is uniformly charged by a corona electrode or a rubber electrode is image-exposed using halogen light or laser light, the charged potential of an exposed portion is attenuated, and an electrostatic latent image is formed. Is formed. Next, a visible image is formed on the electrophotographic photosensitive member by developing the electrostatic latent image using the charged toner as a developer. The visible image is transferred to the transfer material by the Coulomb force and the pressure by the transfer charging. At this time, it is difficult to transfer all the toner, and in order to use the photoconductor repeatedly, it is necessary to clean the residual toner on the photoconductor. Further, after cleaning, the charge history is eliminated by strong exposure, bias application, or the like, and the process proceeds to the next repetitive process.

[0003] Cleaning will be described in more detail. As means for removing fine particles such as toner from the surface of the photoreceptor, cleaning using a fur brush, a magnetic brush, a blade, or the like is known. In particular, blade cleaning is the most widely used cleaning method in recent years because of its high cleaning effect and simple configuration of the apparatus. The cleaning blade has a structure in which an elastic member blade 1 made of a plate-like polyurethane or the like is attached to a support 2 as shown in FIGS.
The photosensitive member is pressed and abutted in the longitudinal direction. As shown in FIG. 5, there are two directions in which the blade comes into contact with the photosensitive member 3 in a forward direction and a counter direction as shown in FIG. Is more preferred. In order to further improve the cleaning effect, it is preferable to increase the contact pressure of the blade 1 with the photoconductor 3.

Improving the above-mentioned cleaning effect is very important for maintaining image quality during repeated use, but has the disadvantage of increasing the frictional force generated between the photosensitive member and the blade. . In other words, an increase in the frictional force between the two causes an increase in the amount of scraping of the photoreceptor and the occurrence of flaws, thereby significantly reducing the life of the photoreceptor.

On the other hand, in recent years, the surface hardness of an electrophotographic photosensitive member using an organic photoconductive material, which has become a mainstream of the electrophotographic photosensitive member due to its advantages such as mass productivity, low cost, and no pollution, is as follows.
Generally lower than those using inorganic photoconductive materials,
An increase in the amount of surface scraping by the cleaning blade and the occurrence of scratches were likely to occur.

Attempts have been made to obtain a high-hardness photosensitive layer using a polymerizable monomer or oligomer. Specifically, JP-A-55-85058 and JP-A-61-41
No. 152, No. 61-201461, No. 62-
201460, JP-A-1-116553,
It is disclosed in JP-A-1-134364 and JP-A-1-134365.

However, the compatibility and dispersibility of monomers and oligomers, and furthermore, the polymerization product thereof and the photoconductive compound are not always good, and the photoconductive compound sometimes deteriorates during the polymerization reaction.

Further, with the recent demand for higher image quality and higher durability, an electrophotographic photosensitive member having more excellent mechanical strength has been studied.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic photoreceptor having a surface layer of high hardness, excellent abrasion resistance and scratch resistance, and excellent durability characteristics. It is in.

Another object of the present invention is to provide an electrophotographic apparatus and an apparatus unit having the above electrophotographic photosensitive member.

[0011]

That is, the present invention provides an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the surface layer of the electrophotographic photosensitive member has the following formula (1):

[0012]

[Outside 3] (Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are H
Or

[0013]

[Outside 3] Wherein R ₇ represents an alkylene group, O, C ＝ O, NH, S or a combination thereof, and R ₈ represents H, CH ₃ and a phenyl group. However, two or more of R _{1 to} R ₆ are not hydrogen at the same time. ) Is obtained by a polymerization reaction of a compound having a structure represented by
An electrophotographic photoreceptor characterized in that the photoreceptor contains a polymer and does not contain conductive particles .

Further, the present invention provides an electrophotographic apparatus and apparatus unit having the above electrophotographic photosensitive member.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the formula (1), specific examples of R _{1 to} R ₆ other than H include the following, but the compounds used in the present invention are not limited to these. .

[0016]

[Outside 5]

Here, R represents R ₈ . R ₈ is preferably H.

In the present invention, R _{1 to} R ₆ may be the same or different from each other, but two or more do not become hydrogen at the same time.

The following compounds are particularly preferable as the compound represented by the formula (1).

[0020]

[Outside 6]

Although the compound used in the present invention is polymerized by radical polymerization, it is a monomer having an extremely high functional group density and a very high reaction rate, so that the polymerization reaction proceeds even under mild conditions. Hard to hurt. Further, it is excellent in compatibility with a photoconductive substance and dispersibility. Furthermore, the polymer (reaction product of the compound of the present invention) has an extremely high hardness, since the functional group density is extremely high.

In the present invention, a polymerization initiator which generates a radical is used to polymerize the monomer. There are two types of radicals, thermal radicals and photo radicals.

Examples of the thermal polymerization initiator that generates a radical by heat include peroxides, azo compounds, tetraalkylthiuram disulfide, and organometallic compounds. These can be used alone, but when two or more kinds are used in combination, the polymerization reaction can be more efficiently advanced in some cases. It is also possible to promote the generation of radicals by combining with a reducing agent. Examples of such a reducing agent include ferrous salts, tertiary amines, naphthenates, mercaptans, and organometallic compounds. Can be

Specific examples of the thermal polymerization initiator are shown below.

[0025]

[Outside 7]

[0026]

[Outside 8]

As the photopolymerization initiator, acetophenone,
Examples include benzoin, benzophenone, thioxanthone, anthraquinone, benzyl, camphorquinone, and Michler's ketone. These generate radicals by light in the ultraviolet region, but are further used in combination with photopolymerization initiation aids such as amines, sulfones and phosphines.
Radicals can be generated more effectively. Since the photopolymerization initiators have different absorption wavelengths, the use of two or more photopolymerization initiators can improve the radical generation efficiency. Further, by using in combination with a sensitizer having an absorption in the visible region, a radical can be generated by visible light.

Specific examples of the photopolymerization initiator, the photopolymerization initiation auxiliary agent and the sensitizer are shown below.

[0029]

[Outside 9]

[0030]

[Outside 10]

[0031]

[Outside 11]

[0032]

[Outside 12]

[0033]

[Outside 13]

[0034]

[Outside 14]

[0035]

[Outside 15]

[0036]

[Outside 16]

[0037]

[Outside 17]

[0038]

[Outside 18]

As a light source for generating a photo radical, an optimum light source is selected depending on the type of a photopolymerization initiator or a sensitizer.
A high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, an electrodeless lamp, a xenon lamp, an excimer laser, a He-Cd laser, and the like are used.

Further, the polymerization reaction can be carried out by generating radicals even in a system containing no initiator by electron beam irradiation. Either a scanning type or a non-scanning type can be used for electron beam irradiation.

The monomers used in the present invention can be polymerized after mixing with other polymerizable monomers and oligomers, and further with other polymer binders. Mixable polymer binders (including those obtained by polymerizing thermoplastic resins and the above-mentioned polymerizable monomers and oligomers) include polyester, polyurethane, polyacrylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, polyamideimide Phenolic resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, melamine resin, polysulfone, polyallyl ether, polyacetal, butyral resin, and fluorine resin. In particular, acrylate, methacrylate, and epoxy-based polymerizable monomers and oligomers have excellent compatibility and are preferable for forming a mixed system.

The photosensitive layer in the present invention may be a single layer type containing a charge generating substance and a charge transporting substance in the same layer, or a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance. May be used. The surface layer in the stacked type may be either the charge generation layer or the charge transport layer. In both the single-layer type and the laminated type, a protective layer can be further provided on the photosensitive layer. In this case, the protective layer is a surface layer. In any case, in the present invention, the surface layer contains a polymerization product of the monomer of the present invention, and forms a surface layer having high hardness and excellent wear resistance.

Examples of the charge generating material used in the present invention include phthalocyanine pigments, polycyclic quinone pigments, trisazo pigments, disazo pigments, azo pigments, perylene pigments, indigo pigments, quinacridone pigments, azulhenium salt dyes, squarium dyes, and cyanine dyes. , Pyrylium dye, thiopyrylium dye, xanthene dye, quinone imine dye,
Triphenylmethane dye, styryl dye, selenium, selenium-tellurium alloy, amorphous silicon, cadmium sulfide and the like.

Examples of charge transport substances include pyrene compounds, N-alkylcarbazole compounds, hydrazone compounds, N, N-dialkylaniline compounds, diphenylamine compounds, triphenylamine compounds, triphenylmethane compounds, pyrazoline compounds, styryl compounds and And stilbene compounds.

In the case of a single layer type, the thickness of the photosensitive layer is from 8 to 40.
μm, particularly preferably 12 to 30 μm. In addition, the content of a photoconductive substance such as a charge generation substance and a charge transport substance is based on the total weight of the photosensitive layer.
It is preferably from 20 to 80% by weight, especially from 30 to 80% by weight.
Preferably, it is 70% by weight.

In the case of the stacked type, the thickness of the charge generation layer is 0.0
It is preferably from 0.01 to 6 μm, especially from 0.01 to 6 μm.
It is preferably 2 μm. The content of the charge generating substance is preferably from 10 to 100% by weight, and particularly preferably from 50 to 100% by weight, based on the total weight of the charge generating layer. The thickness of the charge transport layer is preferably from 5 to 70 μm, particularly preferably from 20 to 50 μm. The content of the charge transport material is preferably from 20 to 80% by weight, and particularly preferably from 30 to 70% by weight, based on the total weight of the charge transport layer.

When a protective layer is provided, its thickness is 0.01
-10 μm, more preferably 0.1-7 μm
It is. The protective layer may contain a charge generating substance or a charge transporting substance in order to obtain more uniform and good conductivity. Further, a titanium coupling agent, a silane coupling agent, various surfactants, or the like may be used as a dispersant.

The layer other than the surface layer does not necessarily need to contain the polymerization product of the monomer of the present invention, and may be formed of the following polymer compound, or a mixture of these compounds or a monomer component. can do. That is, polyester, polyurethane, polyacrylate,
Polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenolic resin, acrylic resin, silicone resin,
Epoxy resins, urea resins, allyl resins, alkyd resins, polyamide imides, polysulfones, polyallyl ethers, polyacetals and butyral resins.

The conductive support of the electrophotographic photoreceptor of the present invention includes iron, copper, gold, silver, aluminum, zinc, titanium,
Metals and alloys such as lead, nickel, tin, antimony and indium, or oxides of the metals, carbon,
A conductive polymer or the like can be used.

Examples of the shape of the support include a drum shape such as a cylindrical shape and a column shape, a belt shape, a sheet shape, and the like, and it is preferable that the shape be an arbitrary shape suitable for an applied electrophotographic apparatus. The conductive material for a support may be molded as it is, dispersed in a resin, used as a coating material, deposited, or processed by etching or plasma treatment. When used as a paint, the substrate to be applied may be paper or plastic, as well as the above metals and alloys.

Further, an undercoat layer may be provided between the conductive substrate and the photosensitive layer. The undercoat layer functions as a barrier layer or an adhesive layer for controlling charge injection at the interface. The undercoat layer is mainly made of a binder resin, but may contain the above-mentioned metal or alloy, or an oxide, salt, or surfactant thereof. As the binder resin for forming the undercoat layer, polyester, polyurethane, polyacrylate, polyethylene,
Polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenolic resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, polyamideimide, polysulfone, polyallyl ether, polyacetal, butyral resin, and the like. . The thickness of the undercoat layer is preferably 0.05 μm to 7 μm, and more preferably 0.1 μm to 2 μm.

The various layers described above can be formed by vapor deposition or coating. In particular, the coating method is preferable because films having various compositions can be formed in a wide range from a thin film to a thick film. Examples of the coating method include a dip coating method, a spray coating method, a beam coating method, a bar coating method, a blade coating method, and a roller coating method.

The electrophotographic photosensitive member of the present invention can be used not only for an electrophotographic copying machine but also for a laser beam printer,
It can be widely used in electrophotographic applications such as CRT printers, LED printers, liquid crystal printers, facsimile machines and laser plate making machines.

As an example, FIG. 7 shows a schematic configuration example of an electrophotographic apparatus having the electrophotographic photosensitive member of the present invention, and FIG. 8 shows a block diagram of a facsimile having the electrophotographic photosensitive member of the present invention.

In FIG. 7, reference numeral 101 denotes an electrophotographic photosensitive member of the present invention as an image carrier, which is driven to rotate at a predetermined peripheral speed in a direction indicated by an arrow around a shaft 101a. The electrophotographic photosensitive member 101 is charged by charging means 10 during its rotation.
2, the peripheral surface thereof is uniformly charged at a predetermined positive or negative potential, and then exposed to light image exposure L (slit exposure, laser beam scanning exposure, etc.) by an exposure unit (not shown) by an exposure unit. 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 developed with toner by developing means 104, and the developed toner is transferred by the transfer means 105 from the paper supply unit (not shown) to the photosensitive member 101 and the transfer means 105.
Is sequentially transferred onto the surface of the transfer material P fed in synchronization with the rotation of the photosensitive member 101.

The transfer material P having undergone the image transfer is separated from the photoreceptor surface and introduced into the image fixing means 108, where the image is fixed, and then printed out as a copy.

After the transfer of the image, the surface of the photoreceptor 101 is cleaned to remove the transfer residual toner by the cleaning means 106, and is subjected to a charge removal treatment by the pre-exposure means 107, and thereafter is repeatedly used for image formation. You.

As the uniform charging means 102 for the photosensitive member 101, a corona charging device is generally widely used. Also, a corona charging device is generally widely used for the transfer device 105. 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 configured to be detachable from the apparatus body. You may.
For example, the photoconductor 101 and the cleaning unit 106 may be integrated into one apparatus unit, and may be configured to be detachable using a guide unit such as a rail of the apparatus body. In this case, 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 may be reflected light or transmitted light from the original, or a laser beam based on a signal obtained by reading the original and forming a signal. Scanning, driving of an LED array, or driving of a liquid crystal shutter array.

When used as a facsimile printer, the light image exposure L is an exposure for printing received data. FIG. 8 is a block diagram showing an example of this case.

The controller 111 is an image reading unit 110
And the printer 119 are controlled. Controller 111
The whole is controlled by the CPU 117. The read data from the image reading unit 110 is transmitted to the partner station through the transmission circuit 113. Data received from the partner station is sent to the printer 119 through the receiving circuit 112. The image memory 116 stores predetermined image data. The printer controller 118 controls the printer 119. 114 is a telephone.

The image information (image information from the remote terminal connected via the line) received from the line 115 is
After being demodulated by the receiving circuit 112, the CPU 117 performs a decoding process and sequentially stores the decoded data in the image memory 116. When the image information of at least one page is stored in the memory 116, the image of the page is recorded. CPU
117 reads out the image information of one page from the memory 116 and sends out the decoded image information of one page to the printer controller 118. Printer controller 1
Upon receiving the image information of one page from the CPU 117, the controller 18 controls the printer to record the image information of the page.

The CPU 117 is connected to the printer 119
During the recording by, the image information of the next page is received.

As described above, image reception and recording are performed.

Hereinafter, the present invention will be described with reference to examples.

[0067]

【Example】

1. An aluminum cylinder having an outer diameter of 80 mm, a wall thickness of 1.5 mm and a length of 363 mm was prepared by mixing and dissolving 10 parts by weight of nylon (M-4000, manufactured by Toray Industries, Inc.), 100 parts by weight of methanol and 90 parts by weight of isopropanol. 2.0 μm after dip coating on top and drying at 90 ° C. for 20 minutes
Was provided.

Next, 10 parts by weight of the following trisazo pigment:

[0069]

[Outside 19] 5 parts by weight of a polycarbonate resin (bisphenol A type, weight average molecular weight 20,000) and 600 parts by weight of cyclohexanone were dispersed in a sand mill to obtain a charge generating layer coating material. This paint is dip-coated on the undercoat layer,
Drying at 20 ° C. for 20 minutes provided a 0.15 μm charge generation layer.

Next, 20 parts by weight of the following biphenyl compound:

[0071]

[Outside 20] 5 parts by weight of the following monomer,

[0072]

[Outside 21] 0.15 parts by weight of the following polymerization initiator

[0073]

[Outside 22] A solution obtained by mixing 15 parts by weight of a polycarbonate resin (bisphenol A type, weight average molecular weight 50,000) and 300 parts by weight of monochlorobenzene was applied onto the charge generating layer by dip coating. After drying at 100 ° C. for 5 minutes, irradiation with ultraviolet light of 1200 μJ / cm ² was performed using a high-pressure mercury lamp, and further drying at 120 ° C. for 60 minutes.
A 5 μm charge transport layer was formed. The electrophotographic photosensitive member thus obtained was evaluated by the following method.

I) Abrasion test An electrophotographic photoreceptor using an aluminum sheet having a thickness of 50 μm instead of an aluminum cylinder was simultaneously produced during the production of the photoreceptor, and the photoreceptor was weighted by a Taber abrasion tester. A wear test was performed at 500 g × 2, 5,000 revolutions, and the weight loss of the photoreceptor was measured.

Table 1 shows the results.

Ii) Scratch test Using a Haydon scratch tester, the surface of the photoreceptor was scratched by a load of 50 g with a 0.5 mm diameter diamond needle, and the depth was measured.

Table 1 shows the results.

Iii) Actual machine test The photoconductor was mounted on a color copier (CLC-200, manufactured by Canon Inc.), and 20,000 sheets were copied in full color using A4 size paper, and the photoconductor was scraped. amount,
The reduction of the dark area potential and the background stain (fog) of the solid white image were measured and evaluated. The fogging was evaluated visually.

Table 1 shows the results.

Comparative Example 1 A charge generation layer was formed in the same manner as in Example 1.

Next, 20 parts by weight of the biphenyl compound used in Example 1 and a polycarbonate resin (bisphenol A)
Mold, weight average molecular weight 50,000) and 300 parts by weight of monochlorobenzene were mixed. This solution was applied onto the charge generation layer by dip coating, and dried at 120 ° C. for 60 minutes to form a charge transport layer having a thickness of 23 μm.

The obtained electrophotographic photosensitive member was evaluated in the same manner as in Example 1.

Table 1 shows the results.

2. 10 parts by weight of the monomer used in Example 1, 0.4 part by weight of the polymerization photoinitiator also used in Example 1 and 90 parts by weight of methyl ethyl ketone were mixed, and this solution was prepared in the same manner as in Comparative Example 1. A spray was applied on the photographic photoreceptor. Drying at 70 ° C. for 10 minutes,
Irradiation with ultraviolet light of 200 μJ / cm ² and drying at 120 ° C. for 60 minutes were sequentially performed to form a 1.2 μm protective layer.

The thus obtained electrophotographic photosensitive member was evaluated in the same manner as in Example 1.

Table 1 shows the results.

Comparative Example 2 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 2 except that the following monomers were used.

[0088]

[Outside 23]

Table 1 shows the results.

3. An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 2 except that the following monomers and a polymerization initiator were used. monomer

[0091]

[Outside 24] Polymerization initiator

[0092]

[Outside 25]

Table 1 shows the results.

4. An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 2 except that the following monomers and a polymerization initiator were used. monomer

[0095]

[Outside 26] Polymerization initiator

[0096]

[Outside 27]

[0097] 5. An undercoat layer was formed in the same manner as in Example 1.

Next, the same charge transport layer as in Comparative Example 1 was provided on this undercoat layer, and the same charge generation layer as in Example 1 was provided on this charge transport layer.

Further, a protective layer similar to that of Example 4 was provided on this charge generation layer.

The thus obtained electrophotographic photosensitive member was evaluated in the same manner as in Example 1. However, in the actual machine test, the polarity of the primary charging, the transfer charging, and the developing bias were reversed by changing the high-voltage transformer.

Table 1 shows the results.

Comparative Example 3 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 5 except that the protective layer was not provided.

Table 1 shows the results.

[0104]

[0105]

[0106]

[0107]

[0108]

6 . 10 parts by weight of the monomer used in Example 1, 0.5 part by weight of the polymerization initiator also used in Example 1,
A solution obtained by mixing 250 parts by weight of methyl ethyl ketone and 250 parts by weight of isopropanol, and a thermoplastically modified polyethylene terephthalate (weight average molecular weight: 20,000)
40 parts by weight and hexafluoroisopropanol 50
A mixture obtained by mixing a solution obtained by mixing 0 parts by weight was spray-coated on an electrophotographic photosensitive member prepared in the same manner as in Comparative Example 1. Dry at 60 ° C. for 5 minutes, 1,500 μJ / cm
After irradiating the ultraviolet ray of No. ^2, the layer was dried at 120 ° C. for 60 minutes to form a 1.1 μm protective layer.

The obtained photoreceptor was evaluated in the same manner as in Example 1.

The results are shown in Table 1.

[0112]

[Table 1]

[0113]

As described above, according to the present invention, an electrophotograph having a high hardness surface layer, excellent wear resistance and scratch resistance, and excellent electrophotographic durability even after repeated use. A photoconductor, an electrophotographic apparatus having the same, and an apparatus unit can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a plan view of a cleaning blade.

FIG. 2 is a diagram illustrating an example of a side view of a cleaning blade.

FIG. 3 is a diagram illustrating another example of a plan view of the cleaning blade.

FIG. 4 is a diagram showing another example of a side view of the cleaning blade.

FIG. 5 is a diagram illustrating an example of an arrangement of a cleaning blade with respect to a photoconductor.

FIG. 6 is a diagram illustrating another example of the arrangement of the cleaning blade with respect to the photoconductor.

FIG. 7 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus having the electrophotographic photosensitive member of the present invention.

FIG. 8 is a diagram showing an example of a block diagram of a facsimile having the electrophotographic photosensitive member of the present invention.

Claims (5)

(57) [Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the surface layer of the electrophotographic photosensitive member has the following formula (1). Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are H or Wherein R ₇ represents an alkylene group, O, C ＝ O, NH, S or a combination thereof, and R ₈ represents H, CH ₃ and a phenyl group. However, two or more of R _{1 to} R ₆ are not hydrogen at the same time. ) Is obtained by a polymerization reaction of a compound having a structure represented by
That polymer contain an electrophotographic photosensitive member, characterized in that it does not contain conductive particles. 2. The electrophotographic photosensitive member according to claim 1, wherein said surface layer is a photosensitive layer. 3. The electrophotographic photoreceptor according to claim 1, wherein said surface layer is a protective layer. 4. An electrophotographic photosensitive member according to claim 1, comprising an electrostatic latent image forming unit, a unit for developing the formed electrostatic latent image, and a unit for transferring the developed image to a transfer material. Electrophotographic equipment. 5. An apparatus unit which integrally supports the electrophotographic photosensitive member according to claim 1, charging means and cleaning means, and is detachable from the apparatus main body.