JPS61124952A - Manufacture of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To hide defects and cracks on a substate to a practically satisfactory level and to improve the smoothness of the surface on which a photosensitive layer is formed by forming a resin layer contg. dispersed electrically conductive and magnetic powder on the substrate as an underlayer and by applying a magnetic field from the inside of the substrate before the resin layer is brought into set to touch. CONSTITUTION:Fine powder of iron, nickel or magnetite may be used as electrically conductive and magnetic powder. Resin for forming an underlayer is selected among polyester resin, acrylic resin, alkyd resin, melamine resin, epoxy resin, phenol resin, etc. in consideration of adhesion to a substrate and the dispersibility of a pigment. A thermosetting resin is preferably used from the viewpoint of solvent resistance. A resin layer contg. dispersed pigment powder is formed on a substate, and a magnetic field of about 500-5,000G is applied from the inside of the substrate for about 30sec-10min before the resin layer is brought into set to touch.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electrophotographic photoreceptor in which an undercoat layer is provided between a conductive substrate and a photosensitive layer.

[Prior art]

In electrophotographic photoreceptors, improvements in adhesion between the substrate and the photosensitive layer, improvement in coating properties of the photosensitive layer, protection of the substrate, covering defects on the substrate, protection against electrical breakdown of the photosensitive layer, and protection from the substrate to the photosensitive layer are used. In order to improve charge injection properties, it is effective to provide an undercoat layer between the substrate and the photosensitive layer.

The first characteristic required of the undercoat layer is electrical characteristics. Since it is used in electrophotographic photoreceptors, it is important that it not affect the electrophotographic properties, and for this purpose, it is necessary that the electrical resistance be low. When the electrical resistance is high, a band of about t'fL is applied to the undercoat layer, and fogging occurs in the image as a so-called residual potential.

Furthermore, it is necessary that the electrical resistance is unaffected by changes in the external environment, in particular by changes in atmospheric humidity. For example, if the electrical resistance increases due to low humidity, fogging will occur.

Conventionally, polyvinyl alcohol, polyvinyl methyl ether, poly-N-vinylimidazole,
Ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, casein, gelatin, polyamide, etc. are used. It is difficult to satisfy the above electrical characteristics with a single resin layer as an undercoat layer, and therefore the resin layer has been used with a very thin film thickness. However, in this case, there is a drawback that the effect of improving image quality by covering defects and scratches on the substrate, which is another major purpose of the undercoat layer, is significantly reduced.

Therefore, it has been proposed to use a resin layer in which conductive pigment powder is dispersed as an undercoat layer as a method of concealing defects in the substrate while satisfying the above-mentioned electrical characteristics. However, if pigment powder is simply blended with resin and applied as an undercoat layer, the surface smoothness of the undercoat layer on the photosensitive layer side (not on the substrate side) may vary depending on the type and particle size of the powder. There is a problem in that the image quality deteriorates due to an insufficient amount of the undercoat layer, or the photosensitive layer laminated as an overlying layer permeates into the voids in the undercoat layer coating.

[Problem that the invention seeks to solve]

An object of the present invention is to manufacture an electrophotographic photoreceptor provided with an undercoat layer that hides defects and scratches on the substrate to a practically sufficient level and improves the smoothness of the surface on the photosensitive layer side. be.

[Means to solve problems]

According to the present invention, in an electrophotographic photoreceptor in which an undercoat layer is provided between the surface of a conductive substrate and a photosensitive layer, a resin layer in which conductive and magnetic powder is dispersed is applied as the undercoat layer on the substrate. , there is provided a method for manufacturing an electrophotographic photoreceptor, characterized in that a magnetic field is applied from inside the substrate while the resin layer is not yet dry to the touch.

Examples of the conductive and magnetic powder used in the present invention include fine powders of iron, ferrite, madanetite, and the like. The particle size of the pigment powder is preferably 1.0 μm or less for primary particles and 1.0 to 5.0 μm for secondary particles. In addition, the resistance value of the pigment powder is preferably 1070.(7) or less when measured by a powder compression method at a pressure of 10017 cm, and the resistance when formed into a coating is preferably in the range of 105 to 1010 Ω.This is sufficient as an undercoat layer. The powder is preferably dispersed in an amount of 50 to 200 parts by weight per 100 parts by weight of the resin in the undercoat layer.

Examples of resins used for the undercoat layer include polyester resin, acrylic resin, vinyl acetate resin, and vinyl chloride resin.
Either thermoplastic resin such as vinyl acetate copolymer resin or thermosetting resin such as alkyd resin, melamine resin, urethane resin, epoxy resin, silicone resin, phenol resin, etc. may be used, and the adhesion with the substrate and pigment dispersibility etc.・Among these, thermosetting resins are more preferable in terms of solvent resistance.

Further, the coating liquid used when forming the undercoat layer can contain various organic solvents. The organic solvent used varies depending on the type of resin, but generally includes alcohols such as methanol, ethanol, imprononol, butanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, N,N-dimethylformamide, Amides such as N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydro7rane, dioxane, ethylene glycol monomethyl ether, esters such as methyl acetate, ethyl acetate, ζchloroform, methylene chloride,
Aliphatic halodanized hydrocarbons such as dichloroethylene, carbon tetrachloride, trichlorethylene, penze/, toluene, xylene, refloin, monochlorobenzene,
Examples include aromatics such as dichlorobenzene. Particularly preferred are butanol, cyclohexanone, and ethylene glycol monomethyl ether. Furthermore, a surfactant such as silicone oil, various silankers, and an f-ring agent may be added to the coating liquid as necessary.

As a means for forming the undercoat layer, for example, a method of dipping the substrate in the above-mentioned coating liquid, a method of spreading the coating liquid onto the substrate, etc. are used.

In the present invention, after the resin in which the pigment powder is dispersed as described above is applied onto the substrate, a magnetic field is applied from inside the substrate before the resin coating becomes vermilion and dry to the touch. is important. In this case, the magnetic particles “stand up” due to the magnetic field.
In order to prevent this and make the surface smoother, it is preferable to apply the magnetic field while rotating.

The magnetic field to be applied is about 500 to 5000 Gauss and 3
The time period is preferably about 0 seconds to 10 minutes. The pigment powder/resin distribution in the undercoating layer after applying the magnetic field shows that the pigment ratio is high on the substrate side,
A magnetic field is applied so that the resin ratio increases on the photosensitive layer side. In this way, defects on the substrate are almost completely hidden, and the surface of the undercoat layer on the photoconductor side is very smooth, so a photoconductor obtained by laminating the photosensitive layer directly on this undercoat layer can be used to produce good electrophotography. images are obtained. Further, a resin layer containing no conductive powder can be further provided on the undercoat layer.

The thickness of the undercoat layer is preferably 5 to 30 microns, particularly 10 to 20 microns. The resin layer (not containing conductive powder) provided thereon has a thickness of 0.1 to 5 microns, preferably 0.2 to 1.0 microns.

To explain the electrophotographic photoreceptor of the present invention in more detail, first, the substrate is a metal such as aluminum, brass, or stainless steel; or polyethylene terephthalate, Iligtylene terephthalate, phenolic resin, polypropylene,
Polymer materials such as nylon and polystyrene, materials such as hard paper are molded into a circular shape, or used as a film or foil.

In the case of an insulator, it is necessary to conduct a conductive treatment, which includes methods such as impregnation with a conductive substance, lamination with metal foil, and metal vapor deposition.

The photosensitive layer includes, for example, dye-sensitized zinc oxide, selenium powder, amorphous silicon powder, polyvinylcarbazole, 7
A talocyanine pigment, an oxazole pigment, etc. are coated on a substrate together with a binder resin if necessary.

Furthermore, when using organic photoconductive materials, an effective method for improving properties is to combine a charge generation layer that generates charge carriers upon exposure to light and a charge transport layer that has the ability to move the generated charge carriers. There is also.

``The charge generation layer may include, for example, azo pigments such as Sudan Red, Diane Blue, and Zenasgeleen B; quinone pigments such as Algol Yellow, Pyrenequinone, and Indanthrene Brilliant Violet RRP; indigo pigments such as quinocyanine pigments, perylene pigments, indigo, and thioindigo; Charge generating substances such as bispenzimitazole Mn such as India 7 Earth Orange Toner, 7 thalocyanine pigment of 87 Talocyanin Nato, quinacridone pigment, pyrylium dye, polyester, polystyrene, polyvinyl acetate, acrylic resin, polyvinyl butyral, etc.
It is formed by being dispersed in a binder resin such as polyvinylpyrrolidone, methylcellulose, hydroxyglobil methylcellulose, and cellulose esters. Alternatively, it can also be formed by vapor deposition or the like. The thickness of the charge generation layer is 0.
It is about 0.05 to 0.2μ.

The charge transport layer may contain, for example, a polycyclic aromatic compound such as anthracene, pyrene, 7-enanthrene, coronene, etc., or indole, carbazole, oxazole, inoxazole, thiazole, imidazole, pyrazole, oxanoazole, pyrazoline, etc. in the main chain or side chain. It is formed by dissolving a hole-transporting substance such as a compound having a nitrogen-containing cyclic compound such as thiadiazole or triazole, or a hydrazone compound in a resin that has film-forming properties. This is because the charge transporting substance generally has a low molecular weight and has poor film-forming properties by itself. Such resins include polycarbonate, polyarylate, polystyrene, polymethacrylates, styrene-methyl methacrylate copolymer,
Examples include polyester, styrene-acrylonitrile copolymer, JIJ sulfone, and the like. The thickness of the charge transport layer is approximately 5 to 20 microns.

〔effect〕

In the present invention, the undercoat layer has a pigment/resin distribution forced by magnetic force so that it is rich in pigment on the substrate side, so defects and scratches on the substrate are sufficiently hidden, and it is rich in resin on the photosensitive layer side. Therefore, its surface has good smoothness.

Hereinafter, the present invention will be specifically explained by examples.

Example 1 100 parts by weight of magnetite powder having a primary particle size of 0.5μ and a secondary particle size of 2μ (manufactured by Toda Kogyo), resol type phenol resin (Priorfen J-3 manufactured by Dainippon Ink Co., Ltd.)
25) in terms of solid content and 40 parts by weight of ethylene glycol monomethyl ether (Kishida Chemical, special grade) were dispersed in a sand mill over 6 hours. Using this dispersion, coat the surface with a depth of 2μ to 5μ and a width of 10μ to 5μ.
The coating was applied to an 80φ x 300m aluminum cylinder with a 0μ scratch by the dipping method to form a 20μ thick undercoat layer, and before the coating was dry to the touch, it was heated at 1000 Gauss as shown in Figure 2 (to). A 60φ cylindrical magnet with a magnetic field was placed inside the cylinder and rotated at 10 rpm for 5 minutes.
It was held in that state for a minute. Figure 3 shows the internal structure of a cylindrical magnet.
Shown below. After the coating film was dry to the touch, it was cured by heating at 150° C. for 30 minutes. After cooling, we measured the roughness of the part where there were scratches on the cylinder and found that the roughness was about 0.4 to 0.8μ.
It was almost the same as the part without scratches.

Next, 10 parts of a sosazo pigment having the following structural formula, 6 parts of cellulose acetate butyrate resin (trade name: CAB-381; Eastman Chemical Exhibition), and 60 parts of cyclohexanone were dispersed for 20 hours in a sand mill apparatus using a 1φ Gollaspiz.

100 parts of methyl ethyl ketone was added to this dispersion, and the mixture was applied onto the undercoat layer by dip coating, followed by heating and drying at 100° C. for 10 minutes to form a charge generation layer with a coating weight of 0.1 Jil/m 3 .

Next, 10 parts of a hydrazone compound having the following structural formula and 12 parts of a styrene-methyl methacrylate copolymer resin (trade name: MS-200, manufactured by Tetsutsu Kagaku ■) were mixed with 7 parts of toluene.
0 parts, and apply this solution on the charge generation layer to give 10 parts.
A charge transport layer having a thickness of 16 μm was formed by drying at 0° C. for 60 minutes.

The photosensitive drum thus produced was processed by a conventional method to jD -5,5
A copying machine that undergoes blade cleaning by kV charged single image exposure, dry toner development, transfer to plain paper, and then blade cleaning by pressing a urethane rubber blade with a hardness of 1 sheet, 70', at an angle of 30 degrees, at a pressure of 4.1 y, at 7 m. It was used for.

When I took a copy of the image, it was high temperature and high humidity, and normal temperature and humidity.

In both low-temperature and low-humidity environments, high-quality images were obtained for peta black images, haaktone images, and peta self-portraits.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a laminated structure of an electrophotographic photoreceptor according to the present invention, FIG. 2 is a flow sheet of the method of the present invention, and FIG. 3 is an internal structure of a cylindrical magnet. 1: Substrate with defects 2: Undercoat layer 3: Resin layer without pigment 4: Charge generation layer 5: Charge transport layer I: Aluminum cylinder with defects ■: Immediately after application of undercoat layer■=By cylindrical magnet Magnetic field application ■: After the undercoat layer dries Agent Patent attorney Sekihira Yamashita Figure 1 Figure 2 ■ Figure 3

Claims (4)

[Claims] (1) In an electrophotographic photoreceptor in which an undercoat layer is provided between the surface of a conductive substrate and a photosensitive layer, a resin layer in which conductive and magnetic powder is dispersed is applied as the undercoat layer on the substrate; A method for producing an electrophotographic photoreceptor, characterized in that a magnetic field is applied from inside the substrate while the resin layer is not yet dry to the touch. (2) The magnetic field is applied such that the powder/resin distribution in the undercoat layer after applying the magnetic field is such that the ratio of powder is high on the substrate side and the ratio of resin is high on the photosensitive layer side. manufacturing method. (3) The manufacturing method according to claim 1, wherein a rotating magnetic field is applied to the undried resin coating film. (4) A patent in which the resistance value of the above powder is 10^7 Ω・cm or less when using a powder compression method at a pressure of 100 g/cm^2, and the resistance when forming a coating film is 10^5 to 10^1^0 Ω・cm. The manufacturing method according to claim 1.