JPH02210455A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the adhesive property of an org. photosensitive layer to a protective surface layer and to obtain superior durability over a long period of time by forming a high hardness thin film made of carbon or based on carbon as the protective surface layer and interposing an intermediate layer based on an oxygen-free resin. CONSTITUTION:An underlayer 2, an electric charge generating layer 3, an electric charge transferring layer 4, an intermediate layer 5 and a protective surface layer 6 are successively formed on an electrically conductive support 1. The layer 6 is made of carbon or based on carbon and the layer 5 is based on an oxygen-free resin. The underlayer 2 optionally formed between the support 1 and a photosensitive layer consisting of the layers 3, 4 further enhances the effect of the photosensitive layer. Unlike the conventional sensitive body the resulting sensitive body does not cause the peeling of the protective surface layer, so a fine copied image can be formed even after repeated use and the durability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor comprising a surface protective layer on an organic photosensitive layer.

[Prior art]

Conventionally, photoreceptors used in electrophotography include those with a photoconductive layer mainly made of selenium or selenium alloys on a conductive support, and inorganic photoconductive materials such as zinc oxide and cadmium sulfate. Generally known methods include those using organic photoconductive materials such as poly-N-vinylcarbazole and trini-I-rofluorenone or azo pigments, and those using amorphous silicon-based materials. It is being

By the way, in general, ``electrophotographic method J'' refers to a photoconductive photoreceptor that is first charged in a dark place by, for example, corona discharge, and then imagewise exposed to selectively dissipate the charge only in the exposed area to create an electrostatic latent material. Image formation in which an image is obtained by obtaining an image, and developing and visualizing this latent image area with electrostatic fine particles (toner) made of coloring materials such as dyes and pigments and binders such as polymeric substances to form an image. It is one of the laws.

The basic characteristics required of the photoreceptor in such electrophotography are (1) the ability to be charged to an appropriate potential in a dark place;

(2) Less charge dissipation in the dark.

(3) Charge can be quickly dissipated by light irradiation.

Examples include.

In addition to these basic characteristics, each of the above photoreceptors has practical usage.
Each of the two has excellent features and drawbacks, but in recent years, organic photoreceptors have made remarkable progress due to their low manufacturing costs, low environmental pollution, and relatively flexible photoreceptor design. .

In general, an organic photoreceptor is one in which a charge-generating material and a charge-transporting material are dispersed or dissolved in a binder resin and coated on a conductive support. A single-layer type with a charge transport function, a charge generation J-(CGL) with a charge generation function, a charge transport layer (CTL) with a function of holding charged charges and transporting charges injected from the CGL, and further necessary A functionally separated type is known, which has a structure in which layers such as J-shaped layers are laminated, which have functions such as blocking the injection of charge from the support or preventing the reflection of light on the support.

These organic photoreceptors have excellent characteristics as mentioned above, but because they are made of organic materials, their surface hardness is low, and they are susceptible to mechanical damage from developer transfer paper, cleaning materials, etc. during actual use in the copying process. It also has the essential drawback of being susceptible to wear and scratches due to heavy loads.

This abrasion of the photosensitive layer causes a decrease in the charging potential, and local scratches cause streak-like abnormal images to appear on copies, both of which are important problems that affect the life of the photoreceptor.

In order to overcome these drawbacks, a method has been proposed in which a protective layer is provided on the surface of the organic photosensitive layer to improve its durability against mechanical loads received inside and outside the copying machine.

For example, a method of providing an organic film on the surface of a photosensitive layer (
Japanese Patent Publication No. 38-015446), method of providing an inorganic oxide (Japanese Patent Publication No. 43-01.4.517), method of laminating an insulating layer after providing an adhesive layer (Japanese Patent Publication No. 43-027591)
), or a by plasma CVD method, photo CVD method, etc.
A method of stacking -3i layer, 5-3j, :N:8 layer, a-5i:O:8 layer, etc. (Japanese Patent Laid-Open No. 57-179859, Japanese Patent Laid-Open No. 59-058437) has been disclosed.

Furthermore, in recent years, the application of high-hardness diamond-like carbon films to protective layers has become active.

For example, one in which a protective layer made of amorphous carbon or hard carbon is provided on the photosensitive layer (Japanese Patent Laid-Open No. 60-249155), and one in which a diamond-like carbon protective layer is provided on the outermost surface (Japanese Patent Application Laid-Open No. 61-255352). , in which a high-hardness insulating layer containing carbon as a main component is formed on a photosensitive layer (Japanese Patent Application Laid-open No. 612
64355) or a protective layer made of a plasma organic polymer film containing at least atoms such as nitrogen atoms, oxygen atoms, halogen atoms, alkali gold m1FA molecules, etc., is provided on the organic photosensitive layer (JP-A-63-97961-4); A protective layer made of an amorphous hydrocarbon film generated by glow discharge containing at least chalcogen atoms, group II atoms, group II atoms, group II atoms, etc. is provided on the organic photosensitive layer (Japanese Patent Laid-Open No. 63
-220166 to 9).

In all of these proposals, carbon or a highly hard thin film mainly composed of carbon (l - It belongs to what is collectively called a carbon film or a diamond-like carbon film).

The photoreceptor obtained by this method has an improved surface hardness of the organic photosensitive layer and is excellent in durability, but the adhesiveness between the protective layer and the organic photosensitive layer is not sufficient, and the photoreceptor may fail in the copying machine. Subsequent research revealed that the protective layer and organic photosensitive layer peeled off at the interface, and that the durability in actual use was not significantly improved.

[Problem to be solved by the invention]

The present invention was made precisely to solve these problems, and its purpose is to improve the adhesion between the organic photosensitive JG and the protection 71 made of carbon or a highly hard thin film mainly composed of carbon. The object of the present invention is to provide a photoreceptor for electrophotography that exhibits improved durability over a long period of time.

[Means to solve the problem]

According to the present invention, the above-mentioned object is to provide an electrophotographic photoreceptor having a structure in which an organic photosensitive layer, an intermediate layer, and a surface protective layer are laminated in this order on a conductive support, the surface protective layer containing carbon or containing carbon as a main component. This is achieved by an electrophotographic photoreceptor characterized in that the intermediate layer is mainly composed of an oxygen-free resin.

Generally, as a binder resin for dispersing or dissolving the charge generating material or charge transporting material of the organic photosensitive layer, a resin having oxygen atoms in its structure such as polyamide, polyvarnish, chill, polyurethane, polycarbonate, etc. is used. It is being

The present inventors conducted thorough studies on the adhesion between a protective layer made of carbon or a highly hard thin film containing carbon as a main component and organic photosensitive Jj9 containing the binder resin as described above.
It has been found that oxygen atoms in this binder resin structure reduce the adhesive force between the protective layer and the organic photosensitive layer.

Further research revealed that in a photoreceptor in which a conductive support, an organic photoconductive layer, an intermediate layer, and a surface protective layer consisting of carbon or a thin film mainly composed of carbon were laminated in this order, an intermediate Iτ group was found. By using an oxygen-free resin, that is, a resin that does not have oxygen atoms in its molecular structure, as a component, the adhesion between the surface protective layer and the photosensitive layer can be greatly improved.
]] and completed the present invention.

Hereinafter, the present invention will be explained along with the drawings.

FIG. 1 is a schematic cross-sectional view of the electrophotographic photoreceptor of the present invention, in which a subbing layer 2, a charge generation layer 713, a charge transport layer M4, an intermediate layer M5, and a surface protection layer 6 are sequentially provided on a conductive support l. It is of composition.

FIG. 2(a) and FIG. 2(b) respectively show structural examples of other electrophotographic photoreceptors of the present invention, and FIG. 2(a)
2, a single-layer type organic photosensitive layer 7 is provided on a conductive support 1 via a subbing layer 2, and an intermediate layer 5 and a surface protection layer M6 are sequentially provided thereon. In b), a charge transport M4 is provided directly on the conductive support 1, and a charge generation layer 3, an intermediate layer 5 and a surface protection layer are further provided in this order.

The conductive support used in the present invention may be a conductor or an insulator treated for conductivity, such as Afl, N1, F
In addition to metals such as 'e, Cu, and Au, or their alloys, polyester, polycarbonate, polyimide,
An insulating substrate such as glass on which a thin film of a metal such as AQ, Ag, or Au or a conductive material such as In2O3 or Sue is formed, paper treated with conductivity, or the like can be used.

There are no particular restrictions on the shape of the conductive support, and any of plate-like, drum-like, and bell-like shapes can be used.

An undercoat layer is provided between the conductive support and the photosensitive layer as necessary for the purpose of further improving the effects of the present invention and improving adhesion.
, AQ,, 03, Inorganic materials such as silane coupling agents, titanium coupling agents, chromium coupling agents, polyamide resins, alcohol-soluble polyamide resins, water-soluble polyvinyl butyral, polyvinyl butyral, PV
A binder resin with good adhesive properties such as A is used.

In addition, ZnO1Tie, Z
A material in which nS or the like is dispersed can also be used. As a method for forming the undercoat layer, when an inorganic material alone is used, sputtering, vapor deposition, etc. are used, and when an organic material is used, a normal coating method is used. Note that the thickness of the undercoat layer is suitably 5 μm or less.

As the organic photosensitive material provided directly or via an undercoat layer on this conductive support, either a single material type or a functionally separated type can be used.

Examples of single-layer photosensitive layers include dye-sensitized zinc oxide,
Photoconductive powder such as titanium oxide and zinc sulfate, selenium powder,
Amorphous silicon powder, Squaric salt pigment, phthalocyanine pigment, azulenium salt pigment, azo pigment, etc. are coated together with a binder resin and/or an electron-donating compound as described below, as required, and pyrylium dye and Examples include those using a composition in which an electron-donating compound is added to a eutectic complex formed from bisphenol A-based polycarbonate. As the binder resin, the same resin as that used in the functionally separated photosensitive layer described later can be used. The thickness of this single-layer type photosensitive layer is suitably 5 to 30 tiles.

On the other hand, an example of a functionally separated photosensitive layer is a charge generation layer (CG
An example is one in which a core layer is a charge transport layer (CTI) and a charge transport layer (CTI).

Charge generation 7m (CGL) for generating and separating latent image charges by image exposure involves dispersing or dissolving inorganic photoconductive powders such as crystalline selenium, arsenic selenide, or organic dyes and pigments in a binder resin. used ;).

Examples of organic dyes as charge-generating substances include C.I. Pigment Blue 25 [Color Index (CI) 21180], C.I. Pigment Red 4
1 (CI 21200), Sea Eye Acid Red 52
(CT45100), CI Basic Rec I':3
(CT 452]0), furthermore, phthalocyanine pigments having a porphyrin skeleton, azulenium salt pigments, squalic salt pigments, and azo pigments having a carbazole skeleton (
(described in JP-A-53-95033), an azo pigment having a styrylstilbene skeleton (JP-A-5:3-1382)
29), an azo pigment having a triphenylamine skeleton (described in JP-A-53-132547),
Azo pigments having a dibenzothiophene skeleton
-21728), azo pigments having an oxadiazole skeleton (described in JP-A-54-12742), azo pigments having a fluorenone skeleton (described in JP-A-54-12742),
22834), an azo pigment having a bisstilbene skeleton (described in JP-A-54-17733),
Azo pigments having a distyryloxadiazole skeleton (described in JP-A No. 54-2129), azo pigments having a distyrylcarbazole skeleton (described in JP-A-54-177+3)
4), triazo pigments having a carbazole skeleton (JP-A-57-195767, JP-A-57-19)
In addition, phthalocyanine pigments such as CI Picment Blue 16 (CI 71.00), CI Bud Brown 5 (CI 73410), etc.
, C.I. Bud Dye (Cal 73030), and perylene pigments such as Argo Scareso hB (manufactured by Violet) and Indus Thread Scarlet 1-R (manufactured by Bayer) can be used.

These charge generating substances may be used alone or in combination of two or more.

The amount of the binder resin is 0 to 100 parts by weight of the charge generating substance.
It is appropriate to use 100 parts by weight, preferably 0 to 5 parts by weight.
It is 0 parts by weight.

Binding resins used in combination with these organic dyes and pigments include polyamide, polyurethane, polyester, epoxy resin,
Polyether-1~, condensation resins such as polyether, polystyrene, polyacrylate, polymethacrylate-1~, poly-N-vinylcarbazole, polyvinyl butyral, styrene-butadiene copolymer, styrene-acryloni-1-lyl copolymer Adhesive and insulating resins such as polymers such as polymers and copolymers may be mentioned.

The charge generation layer is prepared by dispersing a charge generation substance together with a binder resin if necessary using a ball mill, lighter, sand mill, etc. using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, or dichloroethane;
It can be formed by applying an excessively diluted dispersion. Coating can be carried out using a dip coating method, a spray coating method, a bead coating method, or the like.

The thickness of the charge generation layer is suitably about 0.01 to 5 pm, preferably 0.1 to 2 pm.

Further, in the present invention, when a material such as crystalline selenium or an arsenic selenide alloy is used as a charge generating substance, an electron-donating binder and/or an electron-donating organic compound are used in combination. Examples of such electron-donating substances include polyvinylcarbazole and its derivatives (for example, those having a halogen such as chlorine or bromine, or a substituent such as a methyl group or an amino group in the carbazole skeleton), polyvinylpyrene, oxadiazole, pyrazoline, and hydrazone. , diarylmethane, α-phenylstilhene, [-riphenylamine compounds and other nitrogen-containing compounds and diarylmethane compounds, among which polyvinylcarbazole and its derivatives are particularly preferred.

These substances can also be used as a mixture, but in this case it is preferable to add another electron-donating organic compound to polyvinylcarbazole and its derivatives. The content of this type of inorganic charge generating substance is 30 to 9 in the entire layer.
0 weight M% is appropriate. Further, when an inorganic charge generating material is used, the thickness of the charge generating layer is suitably 0.2 to 5 .mu.m.

The charge transport layer (CT1.) is a layer whose purpose is to hold electric charges and to move the electric charges generated and separated in the charge generation layer by exposure and combine them with the held electric charges. In order to achieve the purpose of retaining the charged charges, a high electrical resistance is required, and in order to achieve the purpose of obtaining a high surface potential with the retained charges, a dielectric constant of 7J is required.
It is required to be compact and have good cargo movement.

Charge transport/M for satisfying these requirements is composed of a charge transport material and a binder resin used as necessary. That is, the charge transport layer can be formed by dissolving or dispersing the following substances in a suitable solvent and applying and drying the solution.

Charge transport materials include hole transport materials and electron transport materials.

As hole transport substances, poly-N-vinylcarbazole and its derivatives, poly-γ-carbazolylethyl glutamate and its derivatives, pyrene formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, oxadiazole derivatives , imidazole derivatives, triphenylamine derivatives, 9(p-diethylaminostyryl)anthracene, 1,1bis-(4-dibenzylaminophenyl)propane, styrylanthracene, styrylpyrazoline, 1-razones on phenyl, α-phenyl Examples include electron-donating substances such as stilbene derivatives.

Examples of the electron transport substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-1-linitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone,
2,4,5.7-titrani-1~loxanthone, 2,4゜8-trini[~lothioxanthone, 2,6.8-trinitro411-indeno(1,,2-b,]]thiophenone-4-one■ , 3゜7-trinitrodibenzothiophenone-5,5-dioxai 1~.

These charge transport substances may be used alone or in a mixture of two or more.

Binder resins that may be used as necessary include polystyrene, styrene-acrylonyl-1-lyl copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, and vinyl chloride. -Vinyl acetate copolymer, polyvinyl acid, polyvinylidene chloride, polyacryle-I-resin, phenoxy resin, polyvalent monophonate, cellulose acetate resin, ethylcellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl 1-luene, poly- N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin,
Examples include thermoplastic resins or thermosetting resins such as alkyd resins.

As the solvent, tetrahydrofuran, dioxane, toluene, monochlorobenzene, dichloroethane, methylene chloride, etc. are used.

The appropriate thickness of the charge transport layer is about 5 to 100 μm.

Furthermore, a plasticizer or a leveling agent may be added to the charge transport layer. As a plasticizer, dibutyl phthalate 1 to . Those used as plasticizers for general resins, such as dioctyl phthalate, can be used as they are, and the amount used is 0 to 30% by weight relative to the binder resin. As a leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil are used, and the amount used is O~1 based on the binder resin.
Approximately % by weight is appropriate.

These CGL and CTL are placed on the support from the support side.
L and CTL may be stacked in this order, or CTL and CGL may be stacked in this order.

In the present invention, the protective layer provided on the outermost surface is carbon or carbon-based, preferably has a C-C bond similar to that of diamond having St]3 orbitals, and has a Vickers hardness of 100 to 100. 3000kg/a#, specific resistance (specific resistance) IXIO'~], X1013Ω・■, optical energy band iJ (referred to as gg) is 1.0eV or more, transparent in the infrared or visible region. It is formed from a thin film that has properties.

Such films are generally produced by sputtering or plasma CVD.
The film is formed by a glow discharge decomposition method, a photo CVO method, etc., and the film forming method is not particularly limited, but it has good characteristics because it is a plasma CVD method that produces a film with a sputtering effect. A protective layer can be obtained. A representative example of this is a patent application filed by the present inventor entitled "Composite with Carbon Coating and Method for Manufacturing the Same"
(Japanese Patent Application No. 56-146929, filed September 17, 1982, Japanese Patent Application Laid-open No. 58-49609).

In this method, a substrate is placed on the electrode (cathode side) of a parallel plate plasma CVD device, and the substrate is deposited on two flat surfaces using self-bias. By strongly exciting active species using an excitation method, a highly hard carbonaceous substance can be obtained.

The above method is preferably applied when the substrate is in the shape of a sheet, but if a plasma CVD apparatus such as the one shown in FIG. It is possible to form a film without any

In the figure, (7) is the vacuum chamber of the plasma CVD equipment, and the loading/unloading preliminary chamber (7') is controlled by the gate valve (9).
It is divided into Inside the vacuum chamber (7) is an exhaust system (2 (1)
[Pressure adjustment valve (21), turbo molecular pump (22)
, and a rotary pump (23) to evacuate and maintain a constant pressure.

A reaction tank (50 tons) is installed in the vacuum tank (7).

The reaction tank has a frame structure (2) as shown in Figure 4 (A) and (B).
(has a square or hexagonal shape when viewed from the electrode side) and a hood (8) (8') that covers the openings at both ends.
), and furthermore, a pair of first and second electrodes (3) (
3') (using metal mesh such as aluminum). (30) indicates a gas line introduced into the reaction tank (50), to which various gas containers as shown below are connected, each passing through a flow meter (29) and passing through a nozzle (25) into the reaction tank (50). ).

Carrier gas:)12. Material gas such as Ar: Hydrocarbon gas (methane, ethylene, etc.)
Additive gas: NF3. N)+3. PH,,,B2)1
．． Etching gas=02 Etching gas=02 Etching frame structure (2) contains supports (1) C(1-1), (1,-2), -(1-n)) on which organic photoconductive layers are formed.
are arranged as shown in FIGS. 3(A) and 3(B). Note that each of these supports is arranged as a third electrode as described later.

A pair of power supplies (15) [(15-], ) for applying a first alternating voltage to the electrodes (3) (3'), respectively;
(]-5-2)) is prepared. The frequency of the first alternating voltage is 1 to 100 MHz.

These power supplies are mating 1 to lance (16-
1) Connected to (], , ]6-2. The phase in this matching transformer is adjusted by a phase adjuster, so that they are 180 degrees each other.
Can be supplied with a deviation of 0° or 0°. That is, it has a symmetrical or in-phase output.

One end (4) and the other end (4') of the matching transformer are connected to the first and second electrodes (3) (3'), respectively. Further, the midpoint (5) on the output side of the transformer is held at the ground level. Furthermore, this midpoint (5) and the third electrode, that is, the support (1) l: (1-1), (1,-2),
・A power supply (1-n)) for applying a second alternating voltage between the holder (2) electrically connected to the
7) is provided. The frequency of this second alternating voltage is 1 to 500 KHz.

In this way, plasma is generated between the first and second electrodes (3) (3') by the first alternating voltage. This plasma is transmitted through the upper and lower hoods (8) (8') and the frame structure (
2), so the outer external space (6
), and the plasma potential within the reaction space is homogeneous. The reaction gas introduced into this reaction space through the nozzle (25) is decomposed by the energy of the plasma, accelerated by the negative self-bias (-10 to 600V) applied to the support by the second alternating voltage, and Since the film is formed on the body by sputtering, a film with a dense structure can be obtained.

The output of the first alternating voltage applied to the first and second electrodes is 0.1 to I-Ktl at a frequency of 13.56 MHz.
l, and the output of the second alternating voltage applied to the third electrode or support is 150 Kl (approximately 10 Kl for a frequency of z).
It is 0v.

The reaction gases typically used are ethylene and NF3, the ratio of which is NF3/C2H4 = 1/20 to 4/1, and the pressure inside the vacuum chamber during the reaction is 0.001 to 1. ．． 0to
It is rr.

By such a method, ethylene and NF3 are decomposed in plasma, and a diamond-like thin film (also called DLC) with added N and F is formed on the support.
In the present invention, carbon or a coating mainly composed of carbon is referred to as carbon or a coating mainly composed of carbon. ) is obtained.

Additionally, this film-forming method allows the physical properties (hardness, light transmittance, specific resistance, etc.) of the resulting film to be relatively freely changed by changing film-forming conditions such as reaction pressure and reaction gas mixture ratio. . In particular, the hardness can be greatly varied by the negative self-bias and reaction pressure applied to the support. In addition, this method does not require any particular heating of the support and can form carbon or a film containing carbon as a main component at a low temperature of 150°C or less, so there is no problem even on organic photosensitive layers with low heat resistance. It is possible to deposit a protective layer.

The film thickness of this carbon or protective Jlj mainly composed of carbon is 100 μm to 10 μm, preferably 1000 μm to 2 μm.
It is μm.

If necessary, additives such as halogen elements such as fluorine, nitrogen, phosphorus, and boron may be added to carbon or JILI which is mainly composed of carbon.

The concentration may be uniform or may have a gradient in the depth direction of the film.

In the present invention, an intermediate layer containing oxygen-free resin as a main component is provided between the above-mentioned protective layer and the organic photosensitive layer. Examples of this oxygen-free resin include polyvinyl chloride, polyvinylidene chloride, polystyrene, styrene-acrylic mono-lyl copolymer, styrene-butadiene copolymer,
Acrylonitrile-butadiene-styrene copolymer, polyethylene, polypropylene, fluororesin (trifluorochloroethylene, tetrafluoroethylene, tetrafluoroethylene/6
(propylene fluoride, vinylidene fluoride, etc.), polyvinylcarbazole, and the like.

These resins can be applied by dissolving them in a solvent or by existing methods such as vacuum evaporation or sputtering to form an organic photosensitive layer.
- may be formed as an intermediate layer.

Further, these intermediate layer forming components may be used alone or in combination of two or more. Furthermore, any resin that does not contain oxygen in its molecular structure and has a film-forming ability can be used to achieve this purpose without being limited to the above-mentioned exemplified materials. The thickness of this intermediate layer is preferably in the range of 50 μm to 5 μm. When the film thickness is less than 5 μm, the function as an intermediate layer of the present invention is insufficient;
If it is more than that, a problem arises in that the residual potential becomes high.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 Aluminum cylindrical support (outer diameter 40uwnφ
, a length of 250 mm+) was prepared by dispersing a mixture with the following composition ratio in a ball mill for 12 hours to form an undercoat layer. Pite was coated by a dipping method to form an undercoat layer so that the film thickness after drying was about 2 μm.

[Subbing layer forming liquid]

Tj02 (Tie Bake manufactured by Ishihara Sangyo Co., Ltd.) Single base polyamide resin (C-A-8000 manufactured by Toshisha Co., Ltd.) 1 Methanol 25 A charge generation layer coating solution with the following formulation was dip coated on this subbing layer, and heated at 120°C. de1
It was dried for 0 minutes to form a charge generation layer with a thickness of about 0.15 layers.

[Charge generation layer coating liquid]

Trisazo pigment with the following structure: 30 parts by weight cyclohexanone 360 After dispersing the above mixture in a ball mill for 72 hours, a mixed solvent of cyclohexanone:methyl ethyl ketone = 1:1 (weight ratio) 5
00 parts by weight.

Next, a charge transport layer was formed by dip coating a charge transport layer coating solution having the following formulation on this charge generation layer 2 so that the film thickness after drying was approximately 20 μm.

=25 [Charge transport layer coating liquid] Tetrahydrofuran 80 Furthermore, an intermediate layer forming liquid having the following formulation was applied onto the charge transport layer by a spray method to form an intermediate layer having a thickness of about 2,000 layers.

[Intermediate layer forming liquid]

Toluene 95 Finally, carbon or a protective layer containing carbon as a main component was formed on this intermediate layer using the plasma CVD apparatus shown in FIG. 3 and under the following conditions.

[Protective layer forming conditions]

NF3 flow rate: 50 SCCMC2H4
Flow rate: 150 SCG reaction pressure
: 0.02torr first alternating voltage output :
400W 13.56AHz bias voltage (DC)
: -400V The carbon or carbon-based bond WJm obtained in this way has a specific resistance of I x 10"Ω・cm,
The film had a Vickers hardness of 2300 kg/mm, an optical energy pan width of 1 to 8 eV, and a film thickness of 0.8 μm.

The electrophotographic photoreceptor of Example 1 was manufactured by the above operations.

Example 2 An electrophotographic photoreceptor of Example 2 was produced in exactly the same manner as in Example 1 except that the intermediate layer forming liquid was changed to the following formulation.

[Intermediate layer forming liquid]

1 Hellen Example 3 An electrophotographic photoreceptor of Example 3 was prepared in exactly the same manner as in Example 1 except that the intermediate layer forming liquid was changed to the following formulation.

[Intermediate layer forming liquid]

Toluene 95 Comparative Example 1 An electrophotographic photoreceptor of Comparative Example 1 was produced in exactly the same manner as in Example 1 except that no intermediate layer was formed on the charge transport layer.

The adhesive strength of the surface protective layer of the photoreceptor thus produced was evaluated by Hiro's method.

That is, an adhesive tape (Scotch Mending Tape 810, manufactured by Sumitomo 3M) was attached to the surface of the photoreceptor and then peeled off to evaluate whether or not the surface protective layer would peel off. As a result, no peeling of the surface protective layer was observed in the photoreceptors of Examples 1, 2.3, but in the case of Comparative Example 1, the surface protective layer was peeled off along with the adhesive tape.

In addition, as a result of mounting these photoreceptors in an actual copying process (racer printer) and repeatedly collecting images,
In the case of the photoreceptor of Comparative Example 1, the protection WJ starts from about 2000 sheets.
began to peel off, and an abnormal image with black stripes appeared on the image, making it unusable for practical use.

On the other hand, in the photoreceptors of Examples 1, 2, and 3, no peeling of the protective layer was observed even after 100,000 sheets were printed, and good image quality was maintained.

〔Effect of the invention〕

The electrophotographic photoreceptor of the present invention has an intermediate layer made of an oxygen-free resin between the organic photosensitive layer and the carbon or carbon-based protective layer, so it can be protected like conventional products. y
Since no peeling occurs, a good copy image can be formed even after repeated use, and its durability is extremely excellent.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing the structure of the electrophotographic photoreceptor of the present invention, and FIGS. 2(a) and 2(b) are schematic sectional views showing the structure of another embodiment. Figure 3 shows -:30 1 of the plasma CVD apparatus used for forming the surface protective layer.
This is an explanatory diagram of an example, and FIG. 4 is a plan view of a frame structure (2) of a plasma CVD apparatus. 1. Support, 2. - Subbing layer, 3. Charge generation layer, 4. Charge transport layer, 5.. Intermediate In, 6. Surface protective layer, 7. Photosensitive layer (single layer type).

Claims (1)

[Claims] (1) In an electrophotographic photoreceptor having a structure in which an organic photosensitive layer, an intermediate layer, and a surface protective layer are laminated in this order on a conductive support, the surface protective layer contains carbon or carbon as a main component, and the intermediate layer A photoreceptor for electrophotography, characterized in that the main component is an oxygen-free resin.