JPH03213871A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To prevent occurrence of image trailing by filling recesses, such as pinholes and cracks, present in a protective with an insulating material to form a smooth surface. CONSTITUTION:The insulating material 35 is used for filling the recesses, such as pinholes and cracks, present at least in the protective layer of the electrophotographic sensitive body formed by successively laminating on a conductive substrate an organic type photosensitive layer 30 and, when needed, an interlayer, and the protective layer 33 on the uppermost surface. As a result, the obtained surface is so smooth that foreign matter occurring in the electrophotographic process cannot attach or adhere to it, thus permitting image blurring matter to be made difficult to exist on the surface of the photosensitive body by positively filling the recesses present in the protective layer 33 on the organic photosensitive layer 30 with the insuating material 35, and therefore, the obtained photosensitive body to be freed of problems, such as image trailing and high in durability.

Description

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

"Prior Art" Conventionally, photoreceptors used in electrophotography include those in which an inorganic photoconductive material such as selenium is dispersed in a binder on a conductive support, and those made of poly-N-vinylcarbazole. Those using organic photoconductive materials such as trinitrofluoreon or azo pigments, and those using amorphous silicon-based materials are generally known.

What is the "electrophotographic method" referred to here? In boat fishing, a photoconductive photoreceptor is first charged in a dark place using, for example, a corona discharge, and then exposed to image light to selectively dissipate the charge only in the exposed areas. An electrostatic latent image is obtained, and this latent image area is developed and visualized with electrostatic fine particles (toner) consisting of a coloring material such as a dye or 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 electrophotography are (1) the ability to be charged to an appropriate potential in a dark place;

(2) Less charge dissipation in a dark place.

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

Examples include.

In addition to these basic characteristics, each of the above-mentioned photoconductors has excellent features and disadvantages in practical use, but in recent years, photoconductors that have low manufacturing costs, little environmental pollution, and are relatively free have been developed. Organic photoreceptors are rapidly developing due to their ease of design.

In general, an organic photoreceptor is a material in which a charge transport material is dispersed or dissolved in a binder resin and coated on a conductive support, and has the functions of charge retention, charge generation, and charge transport in one layer. A charge generation layer (CGL) that has a single layer type and a charge generation function, a charge transport layer (CTL) that has a function of holding charged charges and transporting charges injected from the CGL, and further, if necessary, a charge generation layer (CGL) that has the function of charge generation. A functionally separated type is known, which has a laminated layer having functions such as blocking charge injection or preventing light reflection on a 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 difficult to use as a developer when actually used in the copying process.

Due to mechanical loads received from cleaning parts, etc.
It also has the inherent disadvantage of being prone to wear and scratches.

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. 3B-15446), method of providing an inorganic oxide (Japanese Patent Publication No. 43-14517), method of laminating an insulating layer after providing an adhesive layer (Japanese Patent Publication No. 43-27591), or plasma CVD method, photo CVD method, etc. A method of stacking a-5i layer, aSi:N:H layer, a-3i:O:H layer, etc. by
37) etc. have been disclosed. Furthermore, in recent years, the application of high-hardness diamond-like carbon films to protective layers has become active.

For example, a protective layer made of amorphous carbon or hard carbon is provided on a photosensitive layer (Japanese Unexamined Patent Publication No. 6O-249155).

A diamond-like carbon protective layer is provided on the outermost surface (
JP-A-61-255352), a high-hardness insulating layer containing carbon as a main component formed on a photosensitive layer (JP-A-6126)
4355), or nitrogen atoms on the organic photosensitive layer.

A protective layer made of a plasma organic polymer film containing at least atoms such as alkali metal atoms (Japanese Unexamined Patent Publication No. 63-9
7961-4), a protective film made of an amorphous hydrocarbon film generated by glow discharge containing at least chalcogen atoms such as 1m group atoms, Ⅰ group atoms, V group atoms, etc. is provided on the organic photosensitive layer ( Examples include JP-A-63-220166-9).

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

).

"Problem to be Solved by the Invention J Using this method, it became possible to increase the surface hardness of the organic photosensitive layer. However, because the surface became hard, the surface of the photoreceptor did not wear out. Recesses such as pinholes and cranks that originally existed in the organic photosensitive layer were left in their original shape.A surface resistance-lowering substance called a bokeh substance entered into these cracks.
This was causing image blur.

Image smearing refers to a phenomenon in which the surface charge on the photoreceptor, which should originally be retained in the dark, moves easily due to the low resistance of the surface of the photoreceptor, causing the latent image to become blurred and the image to appear washed out. The reduction in resistance on the surface of the photoreceptor is achieved by the fact that so-called blurring substances such as nitrogen oxides generated by corona discharge during the charging process and phosphorus oxides contained in toner react with water in the air and become ionized. Nitrate ions generated here,
It is generated when sulfate ions, ammonium ions, hydroxyl ion protons, etc. serve as carriers for charge transfer. The existence of these blurring substances was known before the surface hardness was increased, but the problem had not become apparent because the surface hardness was low. That is, this is because the blur substance was also removed from the photoreceptor surface along with the soft surface.

However, as shown in Figure 7, because the surface hardness is increased by the surface protection layer (33), cracks or pinholes (34) in the organic photoreceptor layer are preserved in their original shape. The blurring substance enters the recess (34) of the protective film, lowering the resistance of the surface in the vicinity where the blurring substance exists, and since these exist in the recess of the highly hard protective film,
It is not scraped off and always remains on the surface of the photoreceptor, causing image deletion.

``Structure of the Invention'' In order to solve these problems, the present invention provides an electronic photosensitive layer having a structure in which an organic photosensitive layer, an intermediate layer if necessary, and a protective layer are further laminated on the outermost surface in this order on a conductive support. A photographic photoreceptor, which is provided with an insulating material that fills at least recesses such as pinholes and cranks existing in the protective layer, and is smooth to the extent that foreign matter generated in the electrophotographic process cannot attach, adsorb, or exist. This is an electrophotographic photoreceptor characterized by having a surface.

That is, as shown in FIG. 1(B), the organic photoreceptor layer (3
0) By actively filling the recesses (34) present in the upper protective film (33) with an insulating material (35), a state in which the aforementioned blurring substance is difficult to exist on the photoreceptor surface is realized,
There are no problems such as image blurring. This provides a highly durable photoreceptor.

As the conductive support used in the present invention, a conductor or an insulator treated for conductivity is used.

For example, Al on an insulating substrate such as a metal or alloy such as AI, Ni, Fe, Cu, or Au, polyester, polycarbonate, polyimide, or glass.

Examples include those formed with a thin film of a metal such as Ag or Au or a conductive material such as Into or Sno□, or paper that has been subjected to conductive treatment.

Further, there are no particular restrictions on the shape of the conductive support, and plate-like, drum-like, or belt-like ones may be used as required.

As described above, the organic photosensitive layer provided directly or via an undercoat layer on the conductive support includes a single layer type and a functionally separated type.

Examples of single-layer photosensitive layers include dye-sensitized photoconductive powders such as zinc oxide, titanium oxide, and zinc sulfide.

Those formed by coating selenium powder, amorphous silicon powder, squalic salt pigment, phthalocyanine pigment, azulenium salt pigment, azo pigment, etc. together with a binder resin and/or an electron-donating compound described below as necessary; Examples include those using a composition in which an electron donating compound is added to a eutectic complex formed from a pyrylium dye and a bisphenol A 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 μm.

On the other hand, the charge generation layer (CGL) for generating and separating latent image charges by image exposure in the functionally separated photosensitive layer binds inorganic photoconductive powders such as crystalline selenium and arsenic selenide, or organic dyes and pigments. Dispersed or dissolved in agent resin is used.

As an organic dye and pigment as a charge generating substance, for example, C.I. Pigment Blue 25 [Color Index (CI)]
21180), CI Pigment Red 4HCI2
1200), Sea Acid Red 52 (C1
45100).

CI Basic Red 3 (CI 45210), and a phthalocyanine pigment having a porphyrin skeleton.

Azulenium salt pigments, squalic salt pigments, azo pigments with a carbazole skeleton (described in JP-A No. 53-95033), azo pigments with a styrylstilbene skeleton (described in JP-A-53-138229), triphenylamine Azo pigments having a skeleton (Japanese Patent Application Laid-Open No. 53-132
547), an azo pigment having a dibenzothiophine skeleton (described in JP-A-54-21728),
Azo pigments having an oxadiazole skeleton
12742), an azo pigment having a fluorenone skeleton (described in JP-A No. 54-22834), an azo pigment having a bisstilbene skeleton (described in JP-A-54-17)
733), azo pigments having a distyryloxadiazole skeleton (described in JP-A-54-2129), azo pigments having a distyrylcarbazole skeleton (described in JP-A-54-2129),
(described in JP-A No. 54-2129), azo pigments having a distyrylcarbazole skeleton (described in JP-A-54-1773)
4), triazo pigments having a carbazole skeleton (JP-A-57-195767, JP-A No. 57195)
768), and phthalocyanine pigments such as CI Pigment Blue 16 (CI 74100), CI Bud Brown 5 (Cl 73410),
Indigo pigments such as Sea Eye Bud Dye (C173030) 9.

Perylene pigments such as Argo Scarlet B (manufactured by Panolette) and Indus Thread Scarlet 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 polyimide, polyurethane, and polyester.

Condensation resins such as epoxy resins, polycarbonates, and polyethers; polymers and copolymers such as polystyrene, polyacrylates, polymethacrylates, poly-N-vinylcarbazole, polyvinyl butyral, styrene-butadiene copolymers, and styrene-acrylonitrile copolymers. Examples include adhesive properties such as coalescence, and insulating resins.

The charge generation layer contains a charge generation substance, along with a binder resin if necessary, tetrahydrofuran, cyclohexanone,
It can be formed by dispersing using a ball mill, attritor, sand mill, etc. using a solvent such as dioxane or dichloroethane, diluting the dispersion liquid appropriately, and applying the dispersion. Application can be performed 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 .mu.m, preferably 0.1 to 2 .mu.m.

When particles of 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 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, birapurine, and hydrazone. , diarylmethane, α-phenylstilbene.

Nitrogen-containing compounds such as triphenylamine compounds and diarylmethane compounds may be used, and polyvinylcarbazole and its derivatives are particularly preferred. Alternatively, a mixture of these substances may be used. Even when used in combination, it is preferable to add other electron-donating organic compounds to polyvinylcarbazole and its derivatives. The content of this type of inorganic charge generating substance is 30 to 90% by weight of the entire layer.
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 (CTL) 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 charged charges, it is required to have high electrical resistance, and in order to achieve the purpose of obtaining a high surface potential from the retained charges, it is necessary to have a low dielectric constant and good charge mobility. required.

A charge transport layer that satisfies these requirements is composed of a charge transport substance and a binder resin used as necessary. That is, the charge transport layer can be formed by dissolving or dispersing the above-mentioned substances in a suitable solvent and applying and drying the solution.

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

As the hole transport substance, poly-N-vinylcarbazole and its derivatives, poly-T-carbasolylethyl glutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives.

Polyvinylpyrene, polyvinylphenanthrene.

Oxazole derivatives, oxadiazole derivatives.

Imidazole derivatives, triphenylamine derivatives.

9-(p-diethylaminostyryl)anthracene.

Examples include electron-donating substances such as 1.1-bis-(4-dibenzylaminophenyl)propane, styryl anthracene, styryl pyrazoline, phenylhydrazones, and α-phenylstilbene derivatives.

Examples of the electron transport substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone,
2,4,5.7-tetranitroxanthone, 24.8-
1-linitrothioxanthone, 2,6.8-)dinitro-4H-indeno(L2-b)]thiophene-4one 1,3.7-trinitrodibenzothiophenone5.
Examples include electron-accepting substances such as 5-dioxide.

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

Moreover, as a binder resin used as needed, polystyrene, styrene-acrylonitrile copolymer, and styrene-butadiene copolymer.

Styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride.

Polyacrylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyltoluene, poly-N-vinylcarbazole, acrylic resin, silicone resin.

Examples include thermoplastic or thermosetting resins such as epoxy resins, melamine resins, urethane resins, phenolic resins, and alkyd resins.

Solvents include tetrahydrofuran and 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 the plasticizer, those used as plasticizers for general resins, such as dibutyl phthalate and dioctyl phthalate, can be used as they are, and the appropriate amount to be used is about 0 to 30% by weight based on 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 0 to 100% based on the binder resin.
Approximately 1% by weight is appropriate.

These CGL and CTL are placed on the support from the support side.
Even if L and CTL are stacked in this order, CTL.

They may be stacked in the order of CGL.

The insulating material used to fill recesses such as pinholes and cracks on the surface of the photoreceptor must be compatible with the underlying protective film and have high fluidity to the extent that it can fill the recesses.

Examples of such materials include photoresist epoxy resins used in semiconductor manufacturing processes and the aforementioned CTL or CGL.
Examples include organic resins used in

Furthermore, if the recesses reach the organic photoreceptor under the protective film, it is necessary to select the solvent, insulating material, etc. to be used so that the organic photoreceptor is not attacked.

In particular, when the same material as the organic photosensitive layer, which is the base material, was used, the compatibility with the base material was good.

Carbon or a coating mainly composed of carbon and a method for producing the same will be described below.

FIG. 3 shows an example of a device that can be used in the present invention. In the drawing, a reaction vessel (7) of a plasma CVD apparatus is shown.
is the loading/unloading spare chamber (7゛) and the gate valve (9゛).
]. In the gas system (3o), carrier gas is supplied from (31), reactive gas is supplied from (32), additive gas is supplied from (33), etching gas for the reaction vessel is supplied from (34), valve (28), It passes through a flow meter (29) and is introduced into the reaction vessel (7) through a nozzle (25).

The reaction vessel (7) has a frame structure (2) (having a square or hexagonal frame structure when viewed from the electrode side) as shown in FIGS. A hood (8) is attached to the opening to cover the opening.

(8゛). A pair of first and second electrodes (3) having the same shape are disposed in the hoods (8), (8').

(3゛) is made of aluminum metal mesh. The reactive gas is emitted downward from the nozzle (25). The third electrode has an organic photosensitive layer provided on an aluminum cylindrical support.The photosensitive layer is an insulating material in direct current terms, but when a second alternating voltage is applied thereto, in alternating current terms it is substantially It was made into a conductor and a bias was applied. This base (
1) The upper surface to be formed (l゛) is connected to a pair of electrodes (3), (3'
) was maintained in the plasma generated by the Substrates (1-1), (1-2), ... (1n), that is, (
1) has surfaces to be formed (1'-1), (1''-2)...(
1'-n), and an alternating voltage of 1 to 500 KHz to which a second alternating voltage and a negative DC bias are applied is applied. In this case, the DC bias is actively generated by the self-bias accumulated by the second AC power supply in a capacitor (not shown) installed between the second AC voltage source and the third electrode (substrate) and the DC power supply. Either DC bias may be applied. The reactive gas that has become plasma in the glow discharge due to the first high-frequency alternating voltage is uniformly dispersed in the reaction space (40), and this plasma is (2), (8),
(8'), and reactive gas in a plasma state does not reach this outer external space (6) to prevent a coating from adhering to the inner wall of the reaction vessel. In addition, the plasma potential in the reaction space was made homogeneous.

Furthermore, in order to make the potential distribution in the plasma reaction space more equal, alternating voltages of two different frequencies can be applied to the power supply system (14). The first alternating voltage is 1~
It is a high frequency of 100 MIIz, and is transmitted from a pair of power supplies (15-1) and (15-2) to matching transformers (16-1) and (16-2). The phase in this matching transformer is adjusted by a phase adjuster so that the supplies are shifted by 180° or O'' from each other.The matching transformer has a symmetrical or in-phase output, and one end (4) of the transformer and the other The end (4') is connected to a pair of first and second electrodes (3L (3'), respectively.
The output midpoint (5) of the transformer is held at ground level,
A second 1-500 KHz alternating electric field (17) is applied. The output is passed through a capacitor (not shown) to the substrate (1-1'), (1-2'), ... (1-n')
(1) or a holder (2) electrically connected to them.
) is connected to the third electrode.

Thus, plasma (40) is generated in the reaction space.

The exhaust system (10) exhausts unnecessary gas through a pressure regulating valve (11), a turbo molecular pump (12), and a rotary pump (13).

These reactive gases are o,oot in the reaction space (40).
~l, Qtorr, and this frame structure (2) has a quadrilateral or hexagonal shape, for example, in the case of a quadrilateral, as shown in FIG.
The inside was 75 cm, the depth was 75 cm, and the height was 50 cm as shown in the figure.

Then, a cylindrical substrate having a surface to be formed is placed in this (1-1).
, (1-2) ... (1-n) ..., here, 16 wires are arranged at equal intervals. Dummy base materials (1-0) and (1-n+1) are also provided inside the outer frame structure (2) to form a uniform electric field. In such a space, the high frequency of 1 to 100 MHz is 0.5 to 5 - (0.3 to 3 W/cm per unit area)
) to apply the first high frequency voltage. Furthermore, by applying an alternating current bias using a second alternating voltage, -1
A negative self-bias voltage of 0 to -600 V is applied, and a film can be formed while sputtering a reactive gas accelerated by this negative self-bias voltage onto the substrate, and a dense film can be formed. By controlling this negative self-bias voltage, the hardness of the film can be controlled, which is one of the characteristics of the carbon film forming method used in the present invention.

Hydrogen or argon can be used as the carrier gas, hydrocarbons such as methane and ethylene, or carbide gases such as carbon fluoride can be used as the reactive gases, and nitrides such as nitrogen fluoride and ammonia can be used as the additive gases. As the etching gas for the reaction vessel, oxygen or a fluoride gas such as nitrogen fluoride or carbon fluoride can be used. For example, when ethylene and nitrogen fluoride are introduced as reaction gases, a diamond-like carbon film (also referred to as DLC) to which nitrogen and fluorine are added is used. A film can be formed.

The reactive gas is, for example, a mixed gas of ethylene and nitrogen fluoride, and the ratio thereof is NF3/CJ4=1/20 to 4/I. By varying this ratio, the transmittance and resistivity of the coating can be controlled.

The temperature of the substrate is typically maintained at room temperature, but may be heated or cooled as necessary.

Typical characteristics of carbon or a coating mainly composed of carbon created by the above method are that it forms a C-C bond similar to that of diamond with sp3 orbitals, and has a Vickers hardness of 10.
0~3000Kg/ll1m2, specific resistance (specific resistance) 1
xlO' ~ 1 x10+sΩcm, and
The optical energy band width (referred to as Eg) is 1. It has properties similar to transparent diamond in the infrared or visible region having OeV or more, preferably 1.5 to 5.5 eV.

The carbon or carbon-based coating of the present invention is used as a protective layer, and has a thickness of 0.1 to 5 μm, preferably 0.2 to 1 μm, and a specific resistance of 1Q8 to 13Ωcm.
It is preferably 109 to 1012 ΩCm.

Furthermore, the carbon or carbon-based coating used as the protective film of the present invention can be laminated in multiple layers.

In addition, as the protective film, silicon nitride film, silicon oxide film, silicon carbide film, and many other materials can be used as the protective film, and can be applied without changing the idea of the present invention. However, if the protective film is made of something other than carbon or a film mainly made from other industries, there may be a problem with the adhesion to the underlying organic photosensitive layer, and in that case, the protective film may Other techniques are required, such as changing the production conditions to match the underlying material or laminating protective films made of multiple materials to improve adhesion.

As the insulating material to fill the cracks or pinholes in the protective layer, it is preferable to use a material that has high fluidity and can fill minute gaps.

Examples include photoresist, polyimide, organic silicon oxide dissolved in alcohol solution, polyvinylpyrrolidone, polyvinyl alcohol, and other materials that form a film after removing the solvent, or materials that form a film after removing the organic photosensitive layer as the base material. Materials such as those described above for construction may be used.

The present invention will be illustrated below with reference to Examples.

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

1(A) and 1(B), FIG. 1(B) shows a cross-sectional view of the cylindrical electrostatic copying drum of the present invention, and an enlarged view of the main part thereof is shown in FIG. 1(B).

Further, schematic diagrams of the formation process are shown in FIGS. 2(^) to (E).

Aluminum cylindrical support (1) (outer diameter 40mmφ,
An undercoat layer (31) is formed by applying an undercoat forming liquid prepared by dispersing a mixture of the following composition ratio in a ball mill for 12 hours onto a length of 250 mm, using a dipping method to obtain a film thickness of approximately 2 μm after drying. The state shown in Figure 2 (^) was obtained.

[Subbing layer forming liquid] TiO□ (Tie Bake, manufactured by Ishiya Sangyo Co., Ltd.) 1 part by weight Polyamide resin (CM-8000, manufactured by Toshisha Co., Ltd.) 1 part by weight Methanol 25 parts by weight A charge generation layer having the following formulation was applied on the undercoat layer. Dip coating the work solution, 12
It was dried at 0°C for 10 minutes to form a charge generation layer with a film thickness of 0° and 15 μm.

[Charge generation layer coating liquid]

Trisazo pigment with the following structure: 30 parts by weight Polyester resin (Vylon, manufactured by Toyobo Co., Ltd.) 12 parts by weight Cyclohexane: 360 parts The above mixture was dispersed in a ball mill for 72 hours, and then 500 parts by weight of a mixed solvent of cyclohexane:methyl ethyl ketone = 1:1 (weight ratio) Adjust the dilution in 1 part.

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

In this embodiment, this charge generation layer and charge transport layer are referred to as an organic photoreceptor layer (30).

This state is shown in FIG. 2(B).

There is a pinhole in the organic photoreceptor layer (30) in this state.

There is a recess (34) such as a crank. The formation of these recesses is thought to be caused by a number of factors, including dust during the coating process, scratches on the substrate, irregularities in the undercoat layer, and cracks in the organic photoreceptor itself.

[Charge transport layer coating liquid]

Polycarbonate) 10 parts by weight (Product name Panrai 1-C1400: Kijin Kasei ■) Silicone oil 0.0002 parts by weight (Product name
F2O: Shin-Etsu Silicone ■) Tetrahydrofuran
80 layer II Oz on the surface of this organic photosensitive layer
, H, o, etc., plasma treatment using hydrogen was performed. The H2 flow rate was 50 SCCM, plasma was generated by a first alternating electric field (13.56 MHz), and a bias was applied by a second alternating electric field (50 kHz). The DC component of the bias voltage at this time is -1
It was 00V.

Thereafter, carbon or a film containing carbon as a main component was formed as follows.

NF using the apparatus shown in FIG. 3 and the method described above.

The flow rate of C2H4 is 5 SCCM, and the flow rate of C2H4 is 805 CCM.
, reaction pressure Q, Q5Torr, first alternating electric field frequency 1
3.56M) Iz, its output 400-1 second alternating electric field frequency 250KHz, voltage amplitude 100V, DC bias -50V, specific resistance lXl01 on the organic photoreceptor
A first carbon or carbon-based coating (33) having an amorphous or crystalline structure and transparent to infrared or visible light of 3 Ωcm was formed to a thickness of 0.8 μm (center portion). The film forming rate was 500 persons/min, the hardness was 1500 Kg/11+11" in Vickers hardness, and the optical energy band width was 2.4 eν.

Thus, on the organic photosensitive layer (30), a film containing carbon as a main component, especially carbon containing 30 atomic % or less of hydrogen, 0.3 to 3 atomic % of fluorine, and 0,3 to I
It was possible to form carbon mixed with 0 atomic % nitrogen. This state is shown in FIG. 2(C).

Further, the number of oxygen atoms present at the interface between the photosensitive layer and carbon or a coating mainly composed of carbon was 1 atomic % or less.

Next, a protective layer of carbon or a coating mainly composed of carbon (3
3) Pinholes or cracks on the surface (
Fill in 34).

Using a roll coating device as shown in Figure 5,
The recesses (34) of pinholes or cracks existing on the surface of the protective film were actively filled with an insulating material (36).

In this example, a positive photoresist was used as the insulating material (36). Furthermore, since the size of the pinhole or crack to be filled was small, a resist with a viscosity of 50 CP or less was used. If it is more than that, it will be difficult to wrap around the recess or it will take a lot of time, so 50
A viscosity below CP was preferred. In this example, 5
A resist with a viscosity of CP was used.

This resist was placed in the solution reservoir (38) shown in Fig. 5, and the coating roll (37) was rotated at a speed of 100 revolutions per minute to blend the resist onto the roll, and then pressure was applied to the cylinder of the photoreceptor. The photoreceptor cylinder was brought into close contact and rotated 2 to 10 times to apply a resist onto the protective film of the photoreceptor cylinder, thereby forming a resist (36) over the entire surface of the photoreceptor (30) as shown in FIG. 2(D). Next, after pre-baking this resist (50°C, 10 minutes), it is irradiated with ultraviolet light with a wavelength of around 400 nm for 3 seconds, and developed with a specified developer to form the photoresist in the pinhole or crack concavity (34). , and removed the resist from other parts.

At this time, if the ultraviolet light is exposed for too long, enough light will reach the photoresist in the pinholes or cracks, and even the resist in the recesses will be removed during the development process.

Therefore, it is necessary to set conditions for this exposure time in advance.

Next, the resist in the recessed portions was baked again (75° C. for 30 minutes) to complete an electrophotographic photoreceptor having a smooth surface as shown in FIG. 2(E).

"Example 2" This example is an example in which the same material used for the charge transport layer in Example 1 was used to fill the recesses present in the protective layer.

An organic photosensitive layer (30) and a protective layer (33) were formed on an electrostatic copying drum in the same manner as in Example 1, and then the same material as that used for the charge transport layer was dip coated, followed by heat treatment. The applied solvent was blown off to form an organic film on the surface. A metal piece such as a squeegee was applied to the surface of the photoreceptor cylinder to remove the organic film on the surface, and only the recesses were filled with the same organic film as the charge transport layer to complete an electrophotographic photoreceptor with a smooth surface.

"Example 3" This example is an example in which the same material as that used for the charge transport layer in Example 1 was used to fill the recesses present in the protective layer in Example 1.

An organic photosensitive layer (30) and a protective layer (33) are formed on an electrostatic copying drum in the same manner as in Example 1 to temporarily complete a photoreceptor.

Next, the photoreceptor is actually set in an electrophotographic apparatus (41) as shown in Fig. 6, and the electrophotographic process is performed 1,000 to 150,000 times.Next, the photoreceptor is taken out from the electrophotographic apparatus and the surface of the photoreceptor layer is cleaned. After removing the resistance-lowering substance present on the surface, the recesses on the surface of the protective film were filled with an insulating film using a charge transport layer and a filling material to complete an electrophotographic photoreceptor. .

In the case of this embodiment, cracks that are actually installed in the electrophotographic apparatus (41) and generated during the actual process are also filled with an insulating material, so that no new cracks will occur after that. No new white belts were generated during the process.

"Comparative Example" After forming a photoreceptor in the same manner as in Example 1,
A comparison experiment was conducted with a photoreceptor that was not subjected to the process of filling the recesses on the protective film as in .

Each of the photoreceptors manufactured according to these Examples and Comparative Examples was mounted on the same electrophotographic apparatus (41), and the electrophotographic process was performed 1000 times, after which the electrophotographic apparatus (41) was used for 1 hour.
Copies of evaluation manuscripts were compared after performing 5 cycles of the test process in which the test process was performed in such a way that the test process was left in an energized state.

As a result, in the case of the photoreceptor of the present invention, white spots, white bands, etc. did not occur, whereas white spots, white bands, etc. occurred in the photoreceptor of the comparative example.

Furthermore, when the surface resistance of the photoreceptor surface was measured, the photoreceptor of the present invention showed no change in the order of the resistance value compared to its initial surface resistance, and the rate of change (the initial resistance value divided by the measured value) ) was in the range of 1.2 to 2.5.

Further, the rate of change in resistance value of the comparative example was 50 to 1000, indicating a large change in surface resistance.

"Effects" The present invention provides an electrophotographic photoreceptor having a structure in which an organic photosensitive layer and a protective layer are laminated in this order on a conductive support. This fills the photoreceptor with a smooth surface, prevents the formation of low-resistance regions on the surface of the photoreceptor, and prevents defects such as white bands and white spots in the electrophotographic process. It's what I lost.

[Brief explanation of drawings]

FIG. 1 shows an example in which a cylindrical substrate of the present invention is coated with carbon or a film mainly composed of carbon. FIG. 2 shows a schematic diagram of the process of forming the photoreceptor of the present invention. FIG. 3 shows an outline of the plasma CVD apparatus of the present invention, and FIGS. 4(A) and 4(B) show the arrangement of the substrate in the plasma CVD apparatus shown in FIG. 2. FIG. 5 is a schematic diagram of a roller coater used in producing the photoreceptor of the present invention. FIG. 6 shows an electrostatic copying machine incorporating the photoreceptor of the present invention. FIG. 7 shows an enlarged sectional view of the surface of a conventional photoreceptor.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor having a structure in which an organic photosensitive layer and a protective layer are sequentially laminated on a conductive support, which fills at least recesses such as pinholes and cracks existing in the protective layer. An electrophotographic photoreceptor characterized by being provided with an insulating material and having a smooth surface.