JP2995336B2 - Electrophotographic photoreceptor and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention has a surface protective layer mainly composed of carbon or carbon on a photoreceptor, and the surface protective layer is subjected to a modification treatment by laser beam irradiation. The present invention relates to a photoconductor for electrophotography and a method for manufacturing the same.

(Prior art)

Conventionally, as a photoreceptor used in an electrophotographic method, a photoconductive layer mainly composed of selenium or a selenium alloy is provided on a conductive support, and an inorganic photoconductive material such as zinc oxide or cadmium sulfate is used as a binder. Dispersed materials therein, those using an organic photoconductive material such as poly-N-vinylcarbazole and trinitrofluorenone or azo pigment, and those using an amorphous silicon-based material are generally known.

By the way, generally, the “electrophotographic method” means that a photoconductive photoreceptor is first charged in a dark place, for example, by corona discharge, and then exposed to an image, and the electric charge of only the exposed portion is selectively dissipated to electrostatic latent image. An image is formed by developing an image and developing the latent image with visualization fine particles (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. It is one of the laws.

The basic characteristics required of the photoreceptor in such an electrophotographic method include: (1) being capable of being charged to an appropriate potential in a dark place.

(2) Dissipation of electric charge is small in a dark place.

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

Each of the above photoreceptors has excellent characteristics and disadvantages in practical use, in addition to these basic characteristics.

For example, selenium or a selenium alloy (Se-Te, Se-As, Se
-Te-As-based photoreceptors have excellent photosensitivity, but have the disadvantage that the materials themselves are toxic.

Amorphous silicon photoreceptors have high surface hardness and photosensitivity, but their production costs are high, and in actual use the surface is chemically damaged by ozone generated from the charger and other components of the electrophotographic process. It has the drawback that abnormal images such as image deletion are likely to occur.

In recent years, organic photoreceptor layers have been remarkably developed for reasons such as low production cost, low environmental pollution, and relatively free photoreceptor design.

Generally, an organic photoreceptor is a material 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. Single layer type with transport function and charge generation layer (CGL) with charge generation function, charge transport layer (CG with charge retention and transport of charge injected from CGL)
L) Further, there is a function-separated type in which a layer having a function of preventing charge injection from the support or preventing reflection of light on the support, etc. is stacked as required. .

Although these organic photoreceptors have excellent characteristics as described above, they have low surface hardening and are subject to the mechanical load from the developer, transfer, cleaning members, etc. during actual use in the copying process. It also has the disadvantage that wear and scratches are likely to occur.

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 a drawback, a method has been proposed in which a protective layer is provided on the surface of an organic or Se-based photosensitive layer to improve the durability against mechanical loads received inside and outside a copying machine.

For example, a method of providing an organic film on the surface of the photosensitive layer (Japanese Patent Publication No. 38-15446), a method of providing an inorganic oxide (Japanese Patent Publication No. 43-14517), a method of providing an adhesive layer and then laminating an insulating layer (Japanese Patent Publication No. 43-27591), or plasma CVD method, optical CV
A method of laminating an a-Si layer, an a-Si: N: H layer, an a-Si: O: H layer, etc. by the D method or the like (Japanese Patent Publication No. 57-179859, Japanese Patent Application Laid-Open No.
7) is disclosed. These methods are organic or Se
It has been recognized that the photoreceptor of the present invention has a certain effect on the improvement of the mechanical durability of the photoconductor. However, since it is necessary to use a solvent which does not affect the organic photoreceptor in the case of performing the lamination of the organic film, small degree of freedom in selection of material, also O ₃ as all mentioned in the protective layer of silicon
There is an essential problem that it is liable to be scientifically degraded due to, for example, the like, and there are many problems that still need to be solved in practical use.

Against this background, the application of carbon or a high-hardness thin film containing carbon as a main component as a material for a protective layer of a photoreceptor has recently been activated.

For example, a photosensitive layer provided with a protective layer made of amorphous carbon or hard carbon (JP-A-60-249155), and a diamond-like carbon protective layer provided on the re-surface (JP-A-61-249155)
255352), a high-hardness insulating layer mainly composed of carbon formed on a photosensitive layer (Japanese Patent Laid-Open No. 61-264355), or an atom such as a nitrogen atom, an oxygen atom, a halogen atom, or an alkali metal atom on an organic photosensitive layer. Provided with a protective layer comprising a plasma organic polymer film containing at least (JP-A-63-97961-4)
A protective layer comprising an amorphous hydrocarbon film formed by glow discharge containing at least atoms such as chalcogen atoms, group III atoms, group IV atoms and group V atoms on an organic photosensitive layer (Japanese Patent Application Laid-Open No. Sho 63) -220166 to 9).

In each of these proposals, a high-hardness thin film (i-carbon film or carbon-based film) containing carbon or carbon as a main component produced by an ion process (sputtering, plasma CVD, glow discharge decomposition, photo-CVD, etc.) on the surface of the photosensitive layer. It belongs to a so-called diamond-like carbon film.)

In these methods, since the protective layer is obtained by a vapor deposition process, the influence on the organic photoreceptor is small. This protective layer has high hardness, and is organic or Se.
Selected effects in improving the durability of the system photoreceptor have been recognized.

However, even if such a material is used, if it is repeatedly used for a long time in the electrophotographic process, a copy or print image flows under an environment of high humidity or a rapid rise in humidity, so-called "image blur". It has become clear that an abnormal image called "a" occurs.

Such an abnormal image is retained in such a manner that various ions adhering to the surface are taken into the protective film, and forms a hydrophilic compound containing a nitrogen compound, a carboxy group, and an aldehyde group, thereby forming a two-dimensional image on the photoreceptor surface. It became clear that this was caused by a decrease in the dimensional resistance.

In the course of further research, in the sample in which the above-mentioned protective layer was provided on a silicon substrate, the annealing in which the heating was performed at 300 to 400 ° C. for about 15 minutes was able to suppress the reduction in the resistance in the two-dimensional direction on the surface of the protective layer. It became clear that the annealing treatment was effective for improving the protective layer, but since the temperature at which the organic photoconductor can be heated without affecting its properties is up to about 150 ° C. However, annealing cannot be performed by ordinary means such as an electric furnace. Therefore, in order to use a protective layer mainly composed of carbon or carbon on the organic photoreceptor layer, a method of annealing only the protective layer on the surface without affecting the organic photoreceptor must be used. Must.

〔Purpose〕

An object of the present invention is to establish a reforming means that can be implemented without affecting the photoreceptor, with respect to the carbon or the protective layer containing carbon as a main component provided on the surface of the organic photoreceptor in the above-mentioned conventional technology, An object of the present invention is to provide an electrophotographic photoreceptor having mechanical durability and capable of maintaining good environmental resistance and image quality for a long term even when used repeatedly in an electrophotographic process.

[Configuration of the invention]

According to the present invention, the above object is achieved by irradiating a laser beam from an end surface of a surface protective layer in an electrophotographic photosensitive member having a configuration in which at least a photosensitive layer and a carbon or carbon-based surface protective layer are laminated on a conductive support in this order. This is realized by performing a modification treatment on the surface layer by using an annealing method for performing the following.
If the end surface of the surface protective layer referred to here is specifically defined,
As shown in FIG. 1, it is a parallel plane portion where the conductive support, the photoconductor layer, and the protective layer are exposed. The laser irradiation annealing technique of the present invention cannot be used for the curved surface portion shown in the drawing. The laser irradiation annealing technology devised by the present inventors is an application of Snell's law in high fiber communication and the like, that is, in a composite material composed of a certain different material, utilizing a refractive index difference between the materials, a specific material is used. It uses a technology that propagates light only inside.
(This laser irradiation annealing technique will be described later.)
According to this technique, it is possible to perform an annealing process without affecting the organic photoconductor layer and obtain an electrophotographic photoconductor having no abnormal image.

 Hereinafter, the present invention will be described in more detail.

FIG. 2 is a schematic cross-sectional view of the electrophotographic photoreceptor of the present invention. The photoreceptor layer (102) is formed on a conductive support (101), and carbon or carbon subjected to laser irradiation annealing thereon is mainly used. It is composed of a protective layer (103) as a component. Further, as a structure, as shown in FIG. 3, an undercoat layer (104) may be provided between (101) and (102).

Examples of the conductive support used in the present invention include a conductor or a conductor-treated insulator, such as Al, Ni, Fe, Cu, and Au.
Other metals or their alloys, polyester,
A thin film of a metal such as Al, Ag, Au or the like or a conductive material such as In ₂ O ₃ or SnO ₂ formed on an insulating substrate such as polycarbonate, polyimide, glass, or the like, or paper subjected to a conductive treatment can be used.

An undercoat layer provided as needed between the conductive support and the photoreceptor layer is provided for the purpose of improving the adhesion between the photoreceptor layer and the support and preventing interference of incident light, and the like. Si
Inorganic materials such as O, Al ₂ O ₃ , silane coupling agent, titanium coupling agent, and chromium coupling agent, and binders with good adhesive properties such as polyamide resin, alcohol-soluble polyamide resin, water-soluble polyvinyl butyral, polyvinyl butyral, and PVA Resin or the like is used. In addition, a resin in which ZuO, TiO ₂ , ZnS, or the like is dispersed in the resin having good adhesiveness can be used. As a method for forming the undercoat layer, a method such as sputtering or vapor deposition is used when an inorganic material is used alone, and a usual coating method is used when an organic material is used. The thickness of the undercoat layer is suitably 5 μm or less.

As the photoreceptor layer provided directly on the conductive support or via an undercoat layer, any of an inorganic type and an organic type can be applied.

Examples of the inorganic photoconductor layer include Se or a Se alloy (Se-
Single-layer or function-separated photoreceptor layer using Te, Se-As, Se-As-Te etc. or amorphous silicon material (a-Si: H, a
—Si: C, H, a—Si: Ge, H etc.) and a single-layer type or function-separated type photoreceptor layer.

Also, as the organic photoreceptor layer, either a single layer type or a function separated type can be applied.

Examples of the single-layer type photoreceptor layer include dye-sensitized photoconductive powders such as zinc oxide, titanium oxide, and zinc sulfate, selenium powder, amorphous silicon powder, squaric salt pigment, phthalocyanine pigment, azurenium. Salt pigments, azo pigments and the like, if necessary, coated with a binder resin and / or an electron-donating compound described later, or an eutectic complex formed from a pyrylium pigment and a bisphenol A-based polycarbonate, Examples include those using a composition to which a supply compound is added. As the binder resin, the same resin as the function-separated type photoreceptor layer described later can be used. The thickness of the single-layer type photoreceptor layer is suitably from 5 to 30 μm.

On the other hand, as an example of the function-separated type photoreceptor layer, a layer in which a charge generation layer (CGL) and a charge transport layer (CTL) are laminated is exemplified.

The charge generation layer (CGL) for generating and separating latent image charges by image exposure is prepared by dispersing or dissolving inorganic photoconductive powders such as crystalline selenium and arsenic selenide or organic dyes and pigments in a binder resin. Is used.

Examples of organic dyes and pigments as charge generating substances include, for example, C.I. Pigment Blue 25 (Color Index (CI) 21180) and C.I. Pigment Lid 41 (CI2120).
0), CI Acid Red 52 (CI45100), CI Basic Red 3 (CI45210), phthalocyanine pigments having a porphyrin skeleton, azurenium salt pigments, squaric salt pigments, and azo pigments having a carbazole skeleton (JP-A-53-95033) Azo pigment having a styrylstilbene skeleton (described in JP-A-53-138229), an azo pigment having a triphenylamine skeleton (described in JP-A-53-132547), a dibenzothiophene skeleton Azo pigments having an oxadiazole skeleton (described in JP-A-54-12742) and azo pigments having a fluorenone skeleton (described in JP-A-54-12742). No. 22834), an azo pigment having a bisstilbene skeleton (described in JP-A-54-17733), and a distyryloxadiazole skeleton. Azo pigments (described in JP-A-54-2129), azo pigments (JP having distyryl carbazole skeleton 54-17734
And triazo pigments having a carbazole skeleton (JP-A-57-195767) and JP-A-57-195768), and CI Pigment Blue 16 (CI74).
100) or the like; indigo pigments such as C-I Bad Brown 5 (CI73410) and C-I-Dad Dye (CI73030); perylene such as Argo Scarlet B (manufactured by Bio Red), Indus Scarlet R (manufactured by Bayer). A system pigment or the like 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.

Polyamide, polyurethane, polyester, epoxy resin, as a binder resin used in combination with these organic dyes and pigments,
Condensation resins such as polycarbonate and polyether, and polymers and copolymers such as polystyrene, polyacrylate, polymethacrylate, poly-N-vinylcarbazole, polyvinylbutyral, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, etc. And an insulating resin.

The charge generation layer, together with a binder resin if necessary, a ball mill using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, or the like, dispersed by a ball mill, an attritor, a sand mill, or the like,
The dispersion can be formed by appropriately diluting and applying the dispersion. As a coating method, a dip coating method, a spray coat, a bead coat method, or the like can be used.

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

When particles of crystalline selenium or arsenic selenide alloy are used as the charge generating material in the present invention, an electron donating adhesive or an electron donating organic compound is used in combination. Examples of such an electron donating substance 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), polyvinyl pyrene, oxadiazole, pyrazoline, and hydrazone. , Diarylmethane,
Examples include nitrogen-containing compounds such as a-phenylstilbene and triphenylamine compounds, and diarylmethane compounds, and polyvinyl carbazole and its derivatives are particularly preferable. These substances may be used even if they are mixed. In this case, it is preferable to add another electron donating organic compound to polyvinyl carbazole and its derivative. The content of such an inorganic charge generating substance is suitably from 30 to 90% by weight of the whole layer. 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. A high electrical resistance is required to achieve the purpose of retaining charged charges, and a low dielectric constant and good charge mobility are required to achieve the purpose of obtaining a high surface potential with the retained charged charges. Is done.

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-vinyl carbazole and its derivatives, poly-γ-carbazolylethyl glitamate and its derivatives, pyrene formaldehyde condensate and its derivatives, polyvinyl pyrene, polyvinyl phenanthrene, 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 a-phenylstilbene derivatives are exemplified.

Examples of the electron transporting material 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 thiophenone-4-one and 1,3,7-trinitrodibenzothiophenone-5,5-dioxide are exemplified.

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

In addition, polystyrene and styrene-acrylonitrile copolymer are used as the binder resin if necessary. Styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyacrylate resin, phenoxy resin, polycarbonate, acetic acid Cellulose resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin or other thermoplastic resin or thermosetting 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 general 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 finyl silicone oil are used.
About 1% by weight is appropriate.

These CGL and CTL are placed on the support from the support side.
Even if laminated in the order of. CGL and CTL may be stacked in this order.

Further, in the present invention, the intermediate layer provided between the photoreceptor layer and the surface protective layer if necessary, an inorganic material such as SiO is deposited, sputtering, an anodized or the like provided, or a polyimide resin (JP-A-58-30757 and JP-A-58-98739), alcohol-soluble nylon resin (JP-A-60-196766), water-soluble polyvinyl butyral resin (JP-A-60-232553), Resin layers such as polyvinyl butyral resin (JP-A-58-106549) and polyvinyl alcohol can be used.

In addition, a dispersion of pigment particles such as ZnO, TiO ₂ , and ZnS in the resin intermediate layer can also be used as the intermediate layer.

Further, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the intermediate layer of the present invention. The thickness of the intermediate layer is suitably from 0 to 5 μm.

In addition, an antioxidant or a light stabilizer may be added to at least one of the organic photoconductor layer or an intermediate layer provided as needed for the purpose of improving the electrical characteristics of the photoconductor layer. Absent.

In the present invention, the protective layer provided on the photoreceptor layer directly or via the intermediate layer on the outermost surface is composed of carbon or carbon as a main component, and is preferably a CC similar to diamond having SP ³ orbitals. Has bonding, Vickers hardness 100-3000 kg / cm ² , specific resistance (specific resistance) 1 × 10 ⁷ -1
It is a thin film having a value of × 10 ¹³ Ω · cm and having an optical energy bandwidth (Eg) of 1.0 eV or more and having a light-transmitting property in the infrared or visible region.

Such a film is generally formed by sputtering, plasma CVD, glow discharge decomposition, or photo-CVD, and the film formation method is not particularly limited. A protective layer having good characteristics can be obtained by a method of forming a film while forming. As a typical example of this, a patent application “Composite having a carbon film and a method for producing the same” (Japanese Patent Application No. 56-146929, Showa
Filed on September 17, 56, JP-A-58-49609).

In this method, a substrate is arranged on one electrode (cathode side) of a parallel plate type plasma CVD apparatus, and is deposited on the substrate surface using self-bias. The active species is strongly excited by a high frequency excitation method. By doing so, a carbon film having high hardness can be obtained.

The above method is preferably applied to a case where the substrate is a flat plate, but for example, a plasma as shown in FIG.
According to the CVD apparatus, the same protective layer can be formed without being restricted to the shape of the support.

In the figure, (7) is a vacuum chamber of the plasma CVD apparatus, and a load / unload spare chamber (7 ') is operated by a gate valve (9).
It is divided. The inside of the vacuum chamber (7) is evacuated by an exhaust system (20) [consisting of a pressure regulating valve (21), a turbo molecular pump (22), and a rotary pump (23)], and is maintained at a constant pressure.

A reaction tank (50) is provided in the vacuum tank (7).
The reaction tank is a frame structure (2) as shown in FIGS. 5 (A) and 5 (B).
(Has a square or hexagonal shape when viewed from the electrode side)
And a hood (8) that covers the openings at both ends.
(8 '), and a pair of identically shaped first and second electrodes (3) disposed on the hood (8) (8').
(3 ') (using a metal mesh such as aluminum). (30) indicates a gas line to be introduced into the reaction tank (50). Various gas containers as shown below are connected to the reaction tank (50) from the nozzle (25) through the flow system (29). ).

Carrier Gas: H _2, Ar, etc. material gas: hydrocarbons gas (methane, ethylene, etc.) Additives _{Gas: NF 3, NH 3, PH} 3, B 2 H 6 or the like etching gas: O _2, etc. frame structure (2) Among them, a support (1) [(1-1), (1-2),... (1-n)] formed with an organic photoconductive tank is arranged as shown in FIGS. 4 (A) and 4 (B). Is established. Each support is provided as a third electrode as described later.

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

Each of these power supplies has a matching transformer (16-
1) Connect to (16-2). The phase in this matching transformer is adjusted by a phase adjuster and can be supplied 180 ° or 0 ° from each other. That is, it has a symmetric 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. The output middle point (5) of the transformer is maintained at the ground level. Further, this midpoint (5) and the third electrode, ie, supporter (1) [(1-1), (1-2),.
n)] or a power supply (17) for applying a second alternating voltage between the holders (2) electrically connected to them. The frequency of this second alternating voltage is 1-500KHz
It is.

Thus, a plasma is generated between the first and second electrodes (3) and (3 ') by the first alternating voltage. Since this plasma is surrounded by the upper and lower hoods (8) (8 ') and the frame structure (2), it is not emitted to the outer space (6) outside, and the plasma potential in the reaction space is uniform. It has become. The reaction gas introduced into the reaction space through the nozzle (25) is decomposed by the energy of the plasma and accelerated by the negative self-bias (−10 to −600 V) applied to the support by the second alternating voltage, Since the film is formed while being sputtered on the support, a film having a dense structure can be obtained.

The output of the first alternating voltage applied to the first and second electrodes is 0.1 to 1 kW in the case of a frequency of 13.56 MHz, and the output of the second alternating voltage applied to the third electrode or the support is 15
At a frequency of 0 KHz, it is about 100 W.

The reaction gas to be used typically includes the ratio is ethylene and NF ₃ is _{NF 3 / C 2 H 4 =} 1 / 20~4 / 1, the vacuum chamber pressure during reaction is 0.001~1.0torr .

By such a method, ethylene or NF ₃ is decomposed in a plasma and N and F are added on a support to form a diamond-like thin film (also referred to as DLC. (Referred to as a coating mainly composed of carbon).

In addition, in this film forming method, physical properties (hardness, light transmittance, specific resistivity, etc.) of the obtained film can be relatively freely changed by changing film forming conditions such as a reaction pressure and a reaction gas mixing ratio. be able to. In particular, the hardness can be greatly changed by the negative self-bias applied to the support and the reaction pressure. In addition, it is not necessary to heat the support in this method, and it is possible to form a coating containing carbon or carbon as a main component at a low temperature of 150 ° C. or less, so that there is no problem even on an organic photosensitive layer having low heat resistance. It is possible to form a protective layer.

The thickness of the protective layer mainly composed of carbon or carbon is 10
It is from 0 ° to 10 µm, preferably from 1000 ° to 2 µm.

Additives such as fluorine, halogen, nitrogen, phosphorus, and boron can be added to the protective layer containing carbon or carbon as a main component, if necessary, and the concentration thereof is uniform in the depth direction of the film. Alternatively, a gradient may be provided. Further, the protective layer does not need to be a single layer, and may have a multilayer structure in which the presence or absence and type of additives are controlled.

Further, the modification to carbon or a surface protective layer containing carbon as a main component is performed by laser irradiation annealing utilizing the difference in the refractive index between the photoreceptor layer and the protective layer. This applies the so-called Snell's law, which is used in light transmission by optical fibers.

In optical fibers, the optical path portion and the refractive index n ₁ of the (core), when the refractive index of the protective part (cladding) of the n ₂ is in the relationship n _1> n _2, the following equation entry angle of light into the core portion When the angle is set to be equal to or smaller than θ _c (critical angle or total reflection supplementary angle) (the incident angle equal to or smaller than the critical angle is referred to as an incident angle), the irradiated light is transmitted while reflecting only the core portion. No leakage to the cladding occurs. Here, the refractive index of the carbon protective layer obtained in the experiments of the present inventors is 1.7 to 2.4, the refractive index of the organic photosensitive layer is 1.4 to 1.6, and in addition, the open surface portion of the protective layer upper surface, That is, the refractive index of air is 1. That is, the protective layer having a high refractive index is sandwiched between the air having the refractive index and the photoreceptor layer, and has a structure corresponding to the above-described optical fiber. In addition, when the intermediate layer is provided between the protective layer and the photoreceptor layer, the condition for selecting the material of the intermediate layer is that the refractive index is lower than that of the protective layer. In addition, the incident angle naturally changes depending on the refractive index of the intermediate layer material. However, in Examples of the present invention, such an intermediate layer was not particularly provided.

When the three refractive indices are applied to the above-mentioned formula of the critical angle,
By injecting the laser at an incident angle of 19.74 ° or less,
It satisfies Snell's law, and therefore can perform laser annealing only on the protective layer portion.

FIG. 7 schematically shows these incident conditions. This is an example of a case where the laser beam is incident at A below the critical angle, and a case where B is incident above the critical angle.

In the present invention, the core portion of the optical fiber, that is, a thin film containing carbon or carbon as a main material is used as the protective layer, and the organic photoreceptor layer is used as the cladding portion. When combined with another material, the laser incident angle varies due to the difference in the refractive index, but laser annealing can be performed based on the same principle in principle. Therefore, the laser annealing technique of the present invention is such that n ₁ > n ₂ (or n ₂ ′)
Is satisfied, it does not depend on the material used.

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

Example 1 A mixture having the following composition ratio was dispersed on an aluminum cylindrical support (outside diameter 60 mmφ, length 360 mm) on an aluminum cylindrical support (outside diameter 60 mmφ, length 360 mm) by a ball mill for 12 hours. The prepared undercoat layer forming solution was applied by an immersion method so that the film thickness after drying was about 2 μm, to form an undercoat layer.

(Undercoat layer forming liquid)

1 part by weight of TiO ₂ (Taipaek manufactured by Ishihara Sangyo Co., Ltd.) Polyamide resin (CM-8000 manufactured by Toray Industries Co., Ltd.) For 10 minutes to form a charge generation layer having a thickness of about 0.15 μm.

(Charge generation layer coating solution)

30 parts by weight of trisazo pigment having the following structure Polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) 12 parts by weight Cyclohexanone 360 parts by weight 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 cyclohexanone: methylethylketone = 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.

(Charge transport layer coating solution)

Polycarbonate (trade name: Panlite C1400: Teijin Chemicals Ltd.) 10 parts by weight Silicon oil (trade name: KF: Shin-Etsu Silicone Co., Ltd.) 0.0002 parts by weight Tetrahydrofuran 80 parts by weight Next, carbon or carbon is deposited on the charge transport layer. A protective layer as a main component was formed.

The protective layer containing carbon or carbon as a main component thus obtained had a thickness of 0.8 μm, a specific resistance of 1.0 × 10 ¹⁰ Ωcm, and a Vickers hardness of 2300 kg ^f / mm ² .

FIG. 6A is a schematic view of an annealing apparatus using a laser having a spot diameter of about 0.5 μm in the portion of the protective layer of the fixed cylinder under the above conditions.

In the embodiment of the present invention, an Ar ⁺ laser was used.
For example, it is known that laser irradiation annealing is performed in a semiconductor device manufacturing process, but in those processes, an Ar ⁺ laser, a Nd: YAG laser, a CO
Continuous oscillation light such as laser, high-speed repetition Q switch Nd: YAG
Laser pulsed light, ruby laser, glass laser, or the like is used. These lasers may be used in the present invention. A laser beam is guided from the Ar ⁺ laser device (201) having the same central axis as the fixed photosensitive drum (202) toward the photosensitive drum (202) on the central axis. This light beam is reflected by a two-layer reflecting mirror (203) 30 cm away from the drum (202), and emitted at an incident angle that is substantially parallel to the center line of the protective layer (204). Therefore, the aforementioned incident angle condition is sufficiently satisfied. As described above, the photoconductor drum (202)
And the Ar ⁺ laser device (201) are fixed on the same central axis, and only the reflecting mirror (203) rotates on the same central axis as the drum (202) and the Ar ⁺ laser device (201). By rotating the mirror (203), the DLC on the photoreceptor surface
Laser irradiation can be performed on the entire phase. Therefore, the laser spot rotation speed under the above laser annealing conditions is equal to the rotation speed of the reflecting mirror (203).

An example using a single-layer reflecting mirror instead of the two-layer type (6th
(B)) or an example using a prism instead of a reflecting mirror can be considered. In either case, the gist of the present invention that enables annealing to a protective layer provided on a non-heatable substrate can be considered. It does not deviate.

In the present embodiment, the protective layer is annealed by the rotation of the optical system component as described above. However, the protective layer (204) is rotated by rotating the photosensitive drum (202).
Needless to say, the method of applying laser beam irradiation to the present invention also belongs to the gist of the present invention.

Comparative Example 1 A cylindrical photoreceptor was manufactured under the same conditions as in Example 1 except that laser annealing was not performed on the protective layer.

The protective layer in the "Example 2" Example 1 was deposited only on the _{C 2 H 4 / NF C 2} H 4 rather than _3, was laser annealing in the same manner as in Example 1.

Comparative Example 2 A cylindrical photoconductor was manufactured without performing laser annealing on the protective layer in Example 2.

The photoreceptors thus manufactured (Examples 1, 2 and Comparative Examples 1 and 2)
Regarding 2), the image was compared by mounting it on an actual copying process (a negative-positive phenomenon type laser printer). However, the photoreceptor was used with negative charge, and the image evaluation was about 5 lines / mm
The characteristic value was determined as to whether or not the line pattern was well resolved on the print.

 Table 1 shows the results.

From these results, it has been clarified that when the surface protection layer containing carbon or carbon as a main component has been subjected to the laser irradiation annealing treatment, a stable image can be maintained for a long period of time. In addition, no remarkable abrasion was observed in any of the photoconductors after 50,000 cycles.

〔The invention's effect〕

As described above, the electrophotographic photoreceptor of the present invention can maintain stable high image quality for a long period of time because the permeation of the hydrophilic substance into the surface protective layer containing carbon or carbon as a main component is eliminated. it can.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a laser beam irradiation format. 2 and 3 are schematic views showing the structure of the electrophotographic photoreceptor of the present invention. FIG. 4 is a diagram showing an example of a plasma CVD apparatus used for forming a protective layer. FIG. 5 is a plan view of a frame structure of the plasma CVD apparatus. FIG. 6 is a schematic view showing a type of laser irradiation annealing. FIG. 7 is a schematic view showing the principle of light propagation in laser irradiation annealing. (101) conductive support (102) photoreceptor layer (103) protective layer (104) undercoat layer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G03G 5/00 101 G03G 5/147 501

Claims (2)

(57) [Claims] An organic resin photoreceptor layer on a conductive support,
In the electrophotographic photoreceptor provided with a protective layer containing carbon or carbon as a main component on the photoreceptor layer, the protective layer is modified by irradiating a laser beam from an end face of the protective layer. Photoconductor for electrophotography. 2. A step of forming a photoreceptor layer, a step of forming a protective layer containing carbon or carbon as a main component on the photoreceptor layer, and a step of forming a laser beam in the protective layer from an end face of the protective layer. Irradiating the protective layer to modify the protective layer.