JP2979070B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an electrophotographic photosensitive member having a surface protective layer on an organic photosensitive layer.

"Prior art" Conventionally, as a photoreceptor used in an electrophotographic method, a conductive support in which an inorganic photoconductive material such as selenium is dispersed in a binder, poly-N-vinyl carbazole and Those using an organic photoconductive material such as trinitrofluoreon or azo pigment, those using an amorphous silicon-based material, and the like are generally known.

The term "electrophotographic method" as used herein generally means that a photoconductive photoreceptor is first charged in a dark place, for example, by corona discharge, and then subjected to image exposure to selectively dissipate the charges in only the exposed portions, thereby reducing the static electricity. An electrostatic latent image is obtained, and the latent image portion is developed and visualized with an inspection fine particle (toner) composed of a coloring material such as a dye or a pigment and a binder such as a polymer substance to form an image. This is one of the image forming methods.

The basic characteristics required of the photoreceptor in such an electrophotographic method are as follows: (1) The photoreceptor can be charged to an appropriate potential in a dark place.

(2) Dissipation of electric charge is not easy in a dark place.

(3) The charge can be quickly dissipated by light irradiation.

And the like.

Each of the above photoreceptors has excellent characteristics and disadvantages in practical use in addition to these basic characteristics. Among them, in recent years, the production cost is low, the environmental pollution is small, and the relatively free photoreceptor is used. Organic photoconductors have been remarkably developed for reasons such as design.

Generally, an organic photoreceptor is one in which a charge transport material is dispersed or dissolved in a binder resin and coated on a conductive support, and has a single layer function of charge retention, charge generation, and charge transport. Single layer type charge generation layer (CGL) with charge generation function, charge transfer layer (CTL) with charge retention and transport function of charge injected from CGL, and optionally from support A function-separated type in which a layer having a function of preventing charge injection or preventing light reflection on a support or the like is laminated is known.

These organic photoreceptors have excellent characteristics as described above, but have a low surface hardness because of the organic material, and are mechanically exposed to a developer, a cleaning member, etc. during actual use in a copying process. There is also an inherent disadvantage that the load is liable to wear and scratches.

This abrasion of the photosensitive layer causes a decrease in the charging potential,
Local flaws cause streak-like abnormal images on a copy, and are all important problems that affect the life of the photoconductor.

In order to solve such disadvantages, a method has been proposed in which a protective layer is provided on the surface of the organic photosensitive layer to improve the durability against the mechanical load applied 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. 38-15 / 1983)
446), a method of providing an inorganic oxide (Japanese Patent Publication No. 43-14517),
A method of laminating an insulating layer after providing an adhesive layer (JP-B-43-27)
591) or a-S by plasma CVD or photo CVD
A method of laminating an i-layer, an a-Si: N: H layer, an a-Si: O: H layer, and the like (JP-A-57-179859 and JP-A-59-58437) is disclosed.

In recent years, the application of a high-hardness diamond-like carbon film to a protective layer has been activated. For example, a photosensitive layer provided with a protective layer made of amorphous carbon or hard carbon (see
60-249155), a diamond-like carbon protective layer provided on the outermost surface (JP-A-61-255352), and a high-hardness insulating layer containing carbon as a main component formed on a photosensitive layer (JP-A-61-255352).
264355) Alternatively, a protective layer comprising a plasma organic polymer film containing at least atoms such as nitrogen atoms and alkali metal atoms is provided on the organic photosensitive layer (Japanese Patent Application Laid-Open No. 63-97961).
4) An organic photosensitive layer provided with a protective film made of an amorphous hydrocarbon film generated by glow discharge containing at least atoms of chalcogen atoms, group III atoms, group IV atoms, group V atoms, etc. 63-220166-9).

In each of these proposals, carbon or a carbon-based high-hardness thin film (i-carbon film) formed on the surface of an organic photosensitive layer by an ion process (sputtering, plasma CVD, glow discharge method, photo-CVD method, etc.) Alternatively, it belongs to a film generally called a diamond-like carbon film.) By such a method, the surface hardness of the organic photosensitive layer can be increased.

“Problems to be Solved by the Invention” However, there has been a problem that a phenomenon called image flow caused by such lateral charge transfer on a high hardness surface occurs. Here, the image flow means that the latent image is blurred due to the movement of the charge on the surface of the photoconductor at the boundary of the latent image after the formation of the latent image. As a result, blurring also occurs in the image after development.

This is considered to be caused by the surface resistance being reduced due to the adhesion of moisture to the surface of the photoreceptor having a high specific resistance and the movement of the surface charge. Therefore, the image deletion easily occurs in a high humidity environment.

The present invention solves these problems by providing water-repellency to a protective layer formed of carbon or a carbon-based coating provided on the surface of an organic photosensitive layer, thereby reducing the amount of water molecules adhering to the surface. It is an object of the present invention to provide an electrophotographic photoreceptor capable of reducing an image and obtaining a long-term stable image regardless of the use environment.

"Means for Solving the Problems" In the present invention, an organic photosensitive layer, an intermediate layer if necessary, and a protective layer on the outermost surface are laminated in this order on a conductive support to achieve the above object. In the electrophotographic photoreceptor having the above configuration, the protective layer is made of carbon or a film containing carbon as a main component, and the film has water repellency.

As described above, the cause of image deletion and image blur is caused by the movement of the surface charge of the photoreceptor along the surface, and the movement of the surface charge is caused by water ions attached to the surface when proton ions serving as a supply source become carriers. Conceivable.

It is also believed that the nitride generated by the charger during the charging, exposure and development processes reacts with water molecules attached to the surface and becomes a carrier for charge transfer.

Therefore, if the surface is provided with water repellency and the adhesion of water molecules is eliminated, the movement of the surface charge can be prevented, and the image deletion and the image blur can be prevented.

"Constitution of the Invention" As the conductive support used in the present invention, a conductor or an insulator subjected to a conductive treatment is used.

For example, a metal such as Al, Ni, Fe, Cu, Au, or an insulating substrate such as polyester, polycarbonate, polyimide, glass, or the like, a metal such as Al, Ag, Au, or In ₂ O ₃ , SnO ₂
Examples of such materials include those formed with a thin film of a conductive material such as paper, and paper that has been subjected to a conductive treatment.

The shape of the conductive support is not particularly limited, and may be a plate, a drum, or a belt as needed.

Organic photosensitive layers provided directly on the conductive support or via an undercoat layer include a single layer type and a function separation type as described above.

Examples of the single-layer photosensitive layer include dye-sensitized zinc oxide,
Photoconductive powders such as titanium oxide and zinc sulfide, selenium powder,
An amorphous silicon powder, a squaric salt pigment, a phthalocyanine pigment, an azulhenium salt pigment, an azo pigment, or the like, optionally coated with a binder resin and / or an electron-donating compound described later, or a pyrylium dye. 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, those similar to the function-separated type photosensitive layer described later can be used. The thickness of the single-layer type photosensitive layer is suitably from 5 to 30 μm.

On the other hand, as the charge generation layer (CGL) for generating and separating latent image charges by image exposure in the function-separated type photosensitive layer, an inorganic photoconductive powder such as crystalline selenium or arsenic selenide or an organic dye / dye is bound. What is dispersed or dissolved in a resin is used.

As an organic dye / pigment as a charge generating substance, for example, C.I. Pigment Blue 25 [color index (CI) 21
180], C.I. Pigment Red 41 (CI21200), C.I. Acid Red 52 (CI.45100), C.I. Basic Red 3 (CI.45210), and phthalocyanine pigments having a porphyrin skeleton, azulhenium salt pigments, squaric salt pigments, carbazole skeletons Azo pigments having a styrylstilbene skeleton (described in JP-A-53-138229), and azo pigments having a triphenylamine skeleton (described in JP-A-53-138229). JP-A-132547), an azo pigment having a dibenzothiofin skeleton (described in JP-A-54-21728),
Azo pigments having an oxadiazole skeleton (JP-A-54-12
742), azo pigments having a fluorenone skeleton (described in JP-A-54-22834), azo pigments having a bisstilbene skeleton (described in JP-A-54-17733), distyryl oxadi Azo pigments having an azole skeleton (described in JP-A-54-2129), azo pigments having a distyrylcarbazole skeleton (described in JP-A-54-2129), and azo pigments having a distyrylcarbazole skeleton (see JP-A-54-17734), triazo pigments having a carbazole skeleton (JP-A-57-195767, JP-A-57-195767)
195768), phthalocyanine pigments such as C.I. Pigment Blue 16 (CI 74100), indigo pigments such as C.I.Bad Brown 5 (CI 73410), C.I.Dad Dye (CI 73030) 9, and Argo Scar Red Perylene pigments such as B (manufactured by Van Ollet) and Indus Scarlet R (manufactured by Bayer) can be used.

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

The binder resin is used in an amount of 0 to 1 based on 100 parts by weight of the charge generating substance.
It is suitable to use 00 parts by weight, preferably 0 to 50 parts by weight.

Examples of the binder resin used in combination with these organic dyes and pigments include condensation resins such as polyimide, polyurethane, polyester, epoxy resin, polycarbonate, and polyether, and polystyrene, polyacrylate, polymethacrylate, poly-N-vinylcarbazole, and polyvinyl. Butyral, styrene-butadiene copolymer, styrene
Polymers such as acrylonitrile copolymers and adhesive and insulating resins such as copolymers can be used.

The charge generation layer is formed by dispersing the charge generation substance together with a binder resin, if necessary, using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, or dichloroethane using a ball mill, an attritor, or a sand mill.
It can be formed by appropriately diluting the dispersion and applying it. The coating can be performed by 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 μm, and preferably 0.1 to 2 μm.

When particles such as crystalline selenium or arsenic selenide alloy are used as the charge generating substance, they are used in combination with an electron donating binder and / or an electron donating organic compound. Examples of such electron donating substances include polyvinyl carbazole and derivatives thereof (for example, those having a carbazole skeleton having a halogen such as chlorine or bromine, a substituent such as a methyl group or an amino group),
Examples include nitrogen-containing compounds such as polyvinylpyrene, oxadiazole, pyrazoline, hydrazone, diarylmethane, α-phenylstilbene, and triphenylamine-based compounds, and diarylmethane-based compounds. Particularly, polyvinylcarbazole and its derivatives are preferable. Further, these substances may be used as a mixture. Also in the case of mixing and using, it is preferable to add another electron donating organic compound to polyvinyl carbazole and its derivative. The content of this kind of inorganic charge generating substance is 30 to 90% by weight of the whole layer.
Is appropriate. When an inorganic charge generation material is used, the thickness of the charge generation layer is suitably 0.2 to 5 μm.

The charge transport layer (CTL) is a layer for retaining a charged charge and moving the charge generated and separated in the charge generation layer by exposure to combine with the held charged charge. High electrical resistance is required to achieve the purpose of retaining the charged electric charge, and in order to achieve the purpose of obtaining a high surface potential with the retained charged electric charge, a low dielectric constant and good charge mobility are required. Required.

The charge transport layer for satisfying these requirements is composed of a charge transport material and a binder resin used as needed. That is, a charge transport layer can be formed by dissolving or dispersing the above substances in an appropriate solvent, and applying and drying the same.

The charge transport materials include a hole transport material and an electron transport material.

Examples of the hole transport material include poly-N-vinylcarbazole and its derivatives, poly-γ-carbazolylethylglutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, and oxadiene. Azole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyryl) anthracene, 1,1-bis- (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline,
Electron donating substances such as phenylhydrazones and α-phenylstilbene derivatives;

Examples of the electron transporting substance include chloranil, bromanil, tetracyanoethylene, tetracyanoquinonedimethane, 2,4,7-trinitro-9-fluorenone, 2,
4,5,7-tetranitro-9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2- b] Electron accepting substances such as thiophen-4-one, 1,3,7-trinitrodibenzothiophenone-5,5-dioxide.

These charge transport materials are used alone or in combination of two or more.

The binder resin used as needed includes polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. Polymer, polyvinyl acetate, polyvinylidene chloride, polyacrylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy Thermoplastic or thermosetting resins such as resin, melamine resin, urethane resin, phenol resin and alkyd resin.

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

The thickness of the charge transport layer is suitably about 5 to 100 μm.
Further, a plasticizer or a leveling agent may be added to the charge transport layer. As the plasticizer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount of the plasticizer is suitably about 0 to 30% by weight based on the binder resin. As the leveling agent, silicone oils such as dimethyl silicone oil and methyl phenyl silicone oil are used.
A suitable amount is about weight%.

These CGL and CTL are placed on the support from the support side.
Or CTL and CGL in this order.

The carbon or a film containing carbon as a main component and a method for producing the same in the present invention are described below.

FIG. 2 shows an example of an apparatus that can be used in the present invention. In the drawing, the reaction vessel (7) of the plasma CVD apparatus
Is divided by a load / unload spare chamber (7 ') and a gate valve (9). In the gas system (30), the carrier gas is from (31), the reactive gas is from (32), the additive gas is from (33), the etching gas for the reaction vessel is from (34), the valve (28), It is introduced into the reaction system (50) through the nozzle (25) through the flow meter (29).

The reaction system (50) has a frame structure (2) (having a square or hexagonal frame structure as viewed from the electrode side) as shown in FIGS. 3 (A) and 3 (B). In the opening of the hood (8), cover the opening
(8 '). The pair of first and second electrodes (3) and (3 ') having the same shape and arranged on the hoods (8) and (8') are made of aluminum metal mesh. The reactive gas is discharged downward from the nozzle (25). The third electrode has an organic photosensitive layer provided on an aluminum cylindrical support, and the photosensitive layer is an insulating material in terms of direct current, but a second alternating voltage is applied thereto, and substantially in terms of alternating current. It was made conductive and a bias was applied. The formation surface (1 ') on the substrate (1) is formed by a pair of electrodes (3),
It was arranged to be held in the plasma generated in (3 '). The bases (1-1), (1-2),... (1-n), that is, (1) include the surfaces (1′-1), (1′-2),.
(1'-n), and an alternating voltage of 1 to 500 KHz applied with a second alternating voltage and a negative DC bias is applied. In this case, the DC bias is positively generated by the self-bias accumulated by the second AC power supply and the DC power supply in a capacitor (not shown) provided between the second AC voltage source and the third electrode serving as the base. Either of the applied DC bias may be used. The reactive gas which has been turned into a glow discharge plasma by the first high frequency alternating voltage is uniformly dispersed in the reaction space (60), and this plasma is surrounded by (2), (8) and (8 '). The plasma was not emitted to the outer space (6) outside this so as not to adhere to the inner wall of the reaction vessel. Further, the plasma potential in the reaction space was made uniform.

Further, in order to make the potential distribution in the plasma reaction space more uniform, alternating voltages of two kinds of frequencies can be applied to the power supply system (40). The first alternating voltage is 1 to
High frequency of 100MHz, a pair of two power supplies (15-
1) From (15-2), matching transformer (16-1),
(16-2). The phase of the matching transformer is adjusted by a phase adjuster so that the phase difference can be supplied by 180 ° or 0 °. The transformer has a symmetric or in-phase output, and one end (4) and the other end (4 ') of the transformer are connected to a pair of first and second electrodes (3),
(3 '). The output middle point (5) of the transformer is kept at the ground level,
An alternating electric field (17) of 500 KHz is applied. Its output is passed through a capacitor (not shown) to the substrate (1-1 '),
(1-2 '),... (1-n'), ie, (1) or a third electrode of a holder (2) electrically connected thereto.

Thus, plasma (60) is generated in the reaction space. The exhaust system (20) exhausts unnecessary gas through the pressure adjustment valve (21), the turbo molecular pump (22), and the rotary pump (23).

These reactive substrates have a reaction space (60) of between 0.001 and 1.0.
The frame structure (2) has a rectangular shape or a hexagonal shape. For example, in the case of a rectangular shape, the width is as shown in FIG.
75 cm, depth 75 cm, length 50 cm. The cylindrical substrate having the surface to be formed therein is defined as (1-1), (1-2),.
As shown in (1-n)..., Here 16 are arranged at equal intervals. Dummy base materials (1-0), (1-n) for forming an equal electric field also inside the outer frame structure (2).
+1). In such a space, 1-100M
Hz high frequency of 0.5-5KW (0.3-3W / cm ² per unit area)
To apply a first high-frequency voltage. Further, by applying an AC bias by the second alternating voltage, -10 to
A negative self-bias voltage of -600 V is applied, and a reactive gas accelerated by the negative self-bias voltage can be formed on the substrate while being sputtered, and a dense film can be formed. The hardness of the film can be controlled by controlling the negative self-bias voltage, which is one of the features of the carbon film forming method used in the present invention. FIG. 5 shows an example of the relationship between the negative self-bias voltage and the film hardness.

Hydrogen or argon can be used as a carrier gas, a hydrocarbon gas such as methane or ethylene or a carbon gas such as carbon fluoride as a reactive gas, and a nitride gas such as nitrogen fluoride or ammonia can be used as an additive gas. Oxygen or a fluoride gas such as nitrogen fluoride or carbon fluoride can be used as an etching gas for the reaction vessel. When, for example, ethylene and nitrogen fluoride are introduced as a reaction gas, a diamond-like carbon film to which nitrogen and fluorine are added (also referred to as DLC, including DLC to which additives are added, the present invention mainly includes carbon or carbon). (Referred to as a film as a component).

The reactive gas was, for example, a mixed gas of carbon fluoride and nitrogen fluoride such as ethylene and C ₂ F ₆ . The ratio is NF ₃ / C ₂ H ₄ /
= And _{C 2 F 6 = 1/20} / 20~20 / 20/20. By changing this ratio, the transmittance and the specific resistance can be controlled.

 The temperature of the substrate is typically kept at room temperature.

Typical properties of a coating containing carbon as a main component or carbon in the present invention created by above-described method will make a C-C bond similar to diamond having SP ³ orbit, Vickers hardness 100~3000kg / cm ² , Specific resistance (specific resistance) 1 × 10
⁷ to 1 × 10 ¹⁵ Ωcm and an optical energy bandwidth (Eg) of 1.0 eV or more, preferably 1.5 to 5.5 e
It has properties similar to diamond that is transparent in the infrared or visible region having V.

In the present invention, carbon or a film containing carbon as a main component is to be deposited on a substrate which is excited by a first excitation source and is kept in a plasmatized space. , An electric field is applied, the electric field becomes a bias, and ions in the plasma are accelerated by the bias electric field to form a hard film. Therefore, the hardness of the coating can be varied by controlling the value of the bias voltage. The specific resistance of carbon or a film containing carbon as a main component in the present invention is determined by the amount of pentavalent atoms, typically nitrogen (N), present in the film. That is, it can be controlled by the flow rate of a nitride such as NF ₃ or NH ₃ during film formation.

In addition, the inventors have discovered that the amounts of nitrogen and fluorine affect the drainage of the membrane. That is, as the amount of nitrogen is larger and the amount of fluorine is smaller, water is more likely to adhere to the film,
The lower the amount of nitrogen and the higher the amount of fluorine, the higher the water repellency. This is to reduce the humidity of the atmosphere from 50%
It can be seen by observing how the surface resistivity changes when it is changed to 90%. An example is shown in FIG. In FIG. 6, the humidity dependence (2) of a film containing 1 atomic% or more of nitrogen and 2 atomic% or less of fluorine is the humidity of a film containing 1 atomic% or less of nitrogen and 2 atomic% or more of fluorine. It can be seen that the humidity dependency is greater than the dependency (1). Further, the humidity dependence of a film containing 1 atomic% or less of nitrogen and 2 atomic% or more of fluorine is the humidity dependence of the surface resistivity of Teflon, which is generally said to have high water repellency (3)
The film containing nitrogen at 1 atomic% or less and fluorine at 2 atomic% or more has high water repellency.

Further, the carbon or the film containing carbon as a main component of the present invention may have a multilayer structure for the purpose of improving the adhesiveness, increasing the surface hardness, and providing a charge holding layer inside the film.

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

Example 1 This example shows an example in which carbon or a film containing carbon as a main component is formed on a cylindrical organic photosensitive layer as shown in FIG.

An organic photosensitive layer (47) was prepared on an aluminum cylindrical support (4) having the shape shown in FIG.

Aluminum cylindrical support (outer diameter 40mmφ, length 250m
In m), a mixture having the following composition ratio was dispersed by a ball mill for 12 hours, and the prepared undercoat layer forming solution was applied by dipping so that the film thickness after drying was about 2 μm, thereby forming an undercoat layer.

(Undercoat layer forming liquid)

1 part by weight of TiO ₂ (Taipaek manufactured by Ishihara Sangyo Co., Ltd.) 1 part by weight of polyamide resin (CM-8000 manufactured by Toray Industries, Inc.) 1 part by weight of methanol 25 parts by weight Dip coating of the underlayer with a charge generation layer coating solution having the following formulation, The tube was dried at 120 ° C. for 10 minutes to form a charge generation layer having a thickness of about 0.15 μm.

After the above mixture is dispersed in a ball mill for 72 hours, the mixture is further diluted with 500 parts by weight of a mixed solvent of cyclohexane: methyl ethyl ketone = 1: 1 (weight ratio).

Next, a charge transport layer coating solution having the following formulation was applied onto the charge generation layer by dip coating so that the film thickness after drying was about 20 μm, thereby providing a charge transport layer.

Thereafter, a first carbon or a film containing carbon as a main component was provided on the charge transport layer.

Using the apparatus of FIG. 2, the flow rate of NF ₃ was 5 SCCM, the flow rate of C ₂ H ₄ was 80 SCCM, the reaction pressure was 0.05 Torr, the first alternating electric field frequency was 13.56 MHz, the output was 400 W, An alternating electric field frequency of 250 KHz, a voltage amplitude of 200 V, and a DC bias of -100 V have a specific resistance of 1 × 10 ¹³ Ωcm on an organic photoreceptor having an amorphous structure or a crystal structure capable of transmitting infrared or visible light with respect to infrared or visible light. 0.8 μm (central portion) of carbon or a coating mainly composed of carbon was formed. Deposition rate is 500
The Vickers hardness was 1500 kg / mm ^{2 and the} optical energy bandwidth was 2.4 eV. The amount of nitrogen in the film was 1 atomic%. The amount of nitrogen in the film was measured by Auger electron spectroscopy.

The humidity dependency of the surface resistance of the photoreceptor manufactured according to the present embodiment is about 30% when the atmosphere changes from 50% to 90% as shown in FIG. 7 (1). .

Example 2 After forming the same undercoat layer, charge generation layer and charge transport layer on the same support as in Example 1, the same apparatus as in Example 1 was used, and C ₂ F ₆ flow rate 50 SCCM, the flow rate of C ₂ H ₄
30 SCCM, NH ₃ flow rate 4 SCCM, reaction pressure 0.05 Torr, first alternating electric field frequency 13.56 MHz, its output 400 W, second alternating electric field frequency 250 KHz, its voltage amplitude 200 V, DC bias -10
0.8 [mu] m of a first carbon or a carbon-based film having a transparent amorphous or crystalline structure for infrared or visible light having a specific resistance of 1 * 10 < ¹³ > [Omega] cm on an organic photoreceptor at 0 V. (Center). The deposition rate is 800Å /
The Vickers hardness was 1500 kg / mm ^{2 and the} optical energy bandwidth was 2.4 eV.

The amount of fluorine in the film was 10 atomic%, and the amount of nitrogen was 1 atomic%.

As shown in FIG. 7 (2), the humidity dependence of the surface resistance of the photoreceptor manufactured according to this embodiment shows that the surface resistance changes by about 20% when the atmosphere changes from 50% to 90%. .

Comparative Example 1 After forming the same undercoat layer, charge generation layer, and charge transport layer on the same support as in Example 1, using the same apparatus as in Example 1, the flow rate of NF ₃ was determined in the same manner. 80 SCCM, the flow rate of C ₂ H ₄ 8
0SCCM, reaction pressure 0.05 Torr, first alternating electric field frequency 13.56
MHz, its output is 400 W, the second alternating electric field frequency is 250 KHz, its voltage amplitude is 200 V, and DC bias is -100 V. For infrared or visible light with a specific resistance of 1 × 10 ¹⁰ Ωcm on the organic photoreceptor,
First having a translucent amorphous structure or a crystalline structure
0.8 μm (central portion) of carbon or a film containing carbon as a main component. The deposition rate 500 Å / min, hardness Vickers hardness 1500 Kg / mm ² optical energy band width is 2.4eV
Had.

The amount of nitrogen in the film was 4 atomic%, and no fluorine was detected.

As shown in FIG. 7 (3), the humidity dependence of the surface resistance of the photoreceptor manufactured according to this comparative example shows that the surface resistance changes by one digit or more when the atmosphere changes from 50% to 90%. .

The photoconductors manufactured in Examples 1, 2 and Comparative Example were mounted on an actual copying machine, and a copy image was inspected.
No difference was observed in the low humidity condition of about 30 ° C. and 50%, but in the high humidity state of about 30 ° C. and about 90%, the image flow was not observed in the photoconductors manufactured in Examples 1 and 2. Was observed in the photoreceptor prepared in Comparative Example. FIG. 4 shows an actual example. One example of a case where copying was performed in a low humidity state of about 30 ° C. and about 50% and a case where copying was performed in a high humidity state of about 30 ° C. and about 90% using the photoreceptors manufactured in Example 1 and Example 2, respectively ( (A) and (B). There was little difference between them. These are considered to be due to the fact that the amount of nitrogen serving as an attachment center of water molecules was reduced and the fluorine atoms eliminated water molecules, thereby improving drainage. This allows high temperature and high humidity (30 ° C 90
%), A high quality image could be obtained.

Although a single layer is described in the above embodiments, the films described in these embodiments may have a laminated structure.

"Effects" The present invention provides an electrophotographic photoreceptor having a structure in which an organic conductive layer, an intermediate layer, and a protective layer on the outermost surface are laminated in this order on a conductive support. The drum consists of carbon or a carbon-based coating, and the outermost coating is made water-repellent, so the drum can be actively used in high-temperature, high-humidity (30 ° C, 90%) environments. It was possible to form a clear image without having to take measures such as heating.

[Brief description of the drawings]

FIG. 1 shows an example in which carbon or a film containing carbon as a main component is coated on a cylindrical substrate of the present invention. FIG. 2 shows an outline of a plasma CVD apparatus of the present invention. FIGS. 3 (A) and 3 (B) show a method of disposing a substrate in the plasma CVD apparatus shown in FIG. FIG. 4 shows an example of electrostatic copying using an organic photosensitive drum made by the method of the present invention. FIG. 5 shows the relationship between negative self-bias voltage and hardness. FIG. 6 shows the humidity dependence of the surface resistance of the coating. FIG. 7 shows the humidity dependence of the surface resistance of the coating described in Example 1, Example 2, and Comparative Example.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Naoki Hirose 398 Hase, Atsugi-shi, Kanagawa Prefecture Inside Semiconductor Energy Laboratory Co., Ltd. (72) Inventor Mari Sasaki 398 Hase, Atsugi-shi Kanagawa Prefecture Inside Semiconductor Energy Laboratory Co., Ltd. (72) Inventor Junichi Takeyama 398 Hase, Atsugi-shi, Kanagawa Semiconductor Energy Laboratory Co., Ltd. Judge Yasuko Tetsuo Taki (56) References JP-A-64-20558 (JP, A) JP-A-63-220169 (JP, A) JP-A-63-97961 (JP, A) JP-A 60-260045 ( JP, A) JP-A-62-206559 (JP, A)

Claims (1)

(57) [Claims] 1. A conductive support, comprising: an organic photosensitive layer on the conductive support; and a protective layer on the organic photosensitive layer, wherein the protective layer contains 1 atomic% or less of nitrogen. An electrophotographic photoreceptor comprising 2 atomic% or more of fluorine and made of diamond-like carbon having an amorphous structure and formed while applying a negative self-bias by an alternating voltage.