JPS60220356A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enable easy formation of the latent image of a blue original without inserting a filter into a machine body by dispersing a coloring pigment which absorbs effectively <=520nm light of red or yellow, etc. into the binder of an intermediate layer. CONSTITUTION:An inorg. pigment such as zinchromate or org. pigment such as watching red can be effectively used as the red or yellow coloring pigment which absorbs effectively <=520nm light. Curable rubber and thermosetting resin such as polyurethane resin are adequate as the resin for dispersing said coloring pigments. A conductive white pigment such as tin oxide is added together with the coloring pigment to said resin if the formation of the image is made difficult by the increase in residual potential. A resin layer consisting of polyamide or the like which does not contain conductive powder is provided on the resin layer dispersed therein with the pigment powder and an electric charge generating layer and charge transfer layer are formed on the resin layer which does not contain said conductive powder. The electrophotographic sensitive body is thus formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved electrophotographic photoreceptor, and more particularly, the present invention relates to an improved electrophotographic photoreceptor, and more particularly, in order to sharpen the latent image on the electrophotographic photoreceptor for a blue original, the present invention relates to an improved electrophotographic photoreceptor having a substrate and a charge generation layer. This invention relates to an electrophotographic photoreceptor with a specific intermediate layer provided therebetween.

In conventional multilayer electrophotographic photoreceptors consisting of a charge transfer layer and a charge generation layer, charge generation! The spectral absorption of @ is 500n
When copying a blue original with a spectral reflectance peak of 500 nm or less using a general light source such as a halogen lamp, the relative sensitivity to the electrophotographic photoreceptor increases, causing the latent image on the photoreceptor to The disadvantage is that it is more difficult to form than black originals.

In order to make it easier to form a latent image with a blue original, a filter is installed in the image exposure axis that hits the photoconductor to cut off the spectral wavelength in front of the exposure light source, but this method is expensive in terms of cost. There was a drawback.

The present invention eliminates the above-mentioned drawbacks and provides an electrophotographic photoreceptor that can easily form a latent image on a blue original without inserting a filter into the main body of the machine.

The present invention provides an intermediate layer between the charge generation layer and the substrate in order to facilitate the formation of a latent image on a blue original regardless of the absorption spectral distribution of the charge generation layer. This intermediate layer is made by dispersing in a binder resin a colored pigment such as red or yellow that effectively absorbs light of 520 nm or less.

Inorganic pigments such as hashin chromate, strontium yellow, red iron, chromium vermilion, Hg51 red, aureolin, cadmium red, etc. are used as red or yellow colored pigments that effectively absorb light of 5 2-Onm or less, or Organic pigments such as Watching Red, Fast Yellow, and Pyrazolone Red can be used effectively.

The resin in which these colored pigments are dispersed must (a) have strong adhesion to the substrate; (b)
It can be used as long as it satisfies the following conditions: (C) the powder has good dispersibility and (C) sufficient solvent resistance; however, in particular:
Thermosetting resins such as curable rubber, polyurethane resin, epoxy resin, alkyd resin, polyester resin, silicone resin, and acrylic-melamine resin are suitable.

For dispersion, roll mills, ball mills, vibrating ball mills,
By conventional methods such as attritor, sand mill, colloid mill, etc. Wire barcode, blade coating, knife coating, roll coating, screen coating, etc. are suitable for coating when the substrate is sheet-shaped, and dip coating is suitable when the substrate is cylindrical. There is.

However, if this intermediate layer has a volume resistivity of 10<12 >[Omega].alpha. or more when applied to a substrate, it will be difficult to form an image due to the increase in residual resistance when an electrophotographic photoreceptor is prepared.

It is preferable to add a conductive white pigment such as tin oxide to such a paint together with a colored pigment.A charge generation layer is directly applied on a coating film in which the above-mentioned colored pigment or a colored pigment and a conductive white pigment are dispersed. When coated, the pigment particles of the charge generation layer may become embedded in the micropores, or the photosensitivity may change. For this reason, it is preferable to provide a resin layer containing no conductive powder on the resin layer in which the pigment is dispersed. Examples of such resins include water-soluble resins such as polyvinyl alcohol-2, polyvinyl methyl ether, polyvinylethyl ether, polyvinyl pyridine, polyvinyl pyrrolidone, polyethylene oxide, polyacrylic acids, methyl cellulose, ethyl cellulose, polyglutamic acid, casein, gelatin, and starch. Resins such as resins, polyamide resins, phenolic resins, polyvinyl formals, polyurethane distomers, alkyd resins, ethylene-vinyl acetate copolymers, and vinylpyrrolidone-vinyl acetate copolymers are exemplified. According to the results of experiments conducted by the present inventor, polyamide resin was optimal. Polyamide resins are linear polyamides, and are typified by so-called nylons and copolymerized nylons. In the present invention, since it is suitable to apply it on the substrate in a solution state, a low-crystalline or non-crystalline one is preferable. Such a resin can be obtained by copolymerizing a mixture of two or more types of nylon raw materials.

Raw materials for nylon include, for example, caprolactam or 6-aminocaproic acid, which is the raw material for nylon 6, dicarboxylic acids such as hexamethylene diamine and adipic acid, and sebacic acid, which are the raw materials for nylon 66 and nylon 610.
11-aminolanticanic acid, a raw material for nylon 11,
ω-laurolactam or 1, which is the raw material for nylon 12
Examples include 2-aminododecanoic acid.

The coating thickness of the polyamide resin layer is preferably about 0.3 to 2 microns. A lower charge generation layer and a charge transport layer are formed on this resin layer not containing conductive powder to obtain an electrophotographic photoreceptor.

The charge generation layer in the present invention includes azo pigments such as Sudan Red, Diane Blue, and Jenas Green B, quinone pigments such as Algol Yellow, Pyrenequinone, and Indanthrene Brilliant Violet RRP, quinocyanine pigments, perylene pigments, indigo, thioindigo, and the like. Charge-generating substances such as indigo pigments, bisbenzimidazole pigments such as India Fast Orange toner, phthalocyanine pigments such as copper phthalocyanine, and quinacridine pigments, polyester, polystyrene, polyvinyl butyral, polyvinyl pyrrolidone, methylcellulose, polyacrylic acid esters, and cellulose. Ester is formed by being dispersed in a binder resin. Its thickness is 0.01~1
μ, preferably about 0.05 to 0.5 parts.

In addition, the charge transport layer may contain polycyclic aromatic compounds such as anthracene, pyrene, phenanthrene, coronene, or indole, carbazole, oxazole, isoxazole, thiazole, imidazole, pyrazole, 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 oxadiazole, pyrazoline, 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. Examples of such resins include polycarbonates, polymethacrylates, polyarylates, polystyrene, polyesters, polysulfones, styrene-acrylonitrile copolymers, styrene-methyl methacrylate copolymers, and the like. The thickness of the charge transport layer is 5-20μ
It is.

Additionally, the present invention allows the substrate to be selected from a wide variety of conductive materials. Specifically, examples include metals such as aluminum, brass, stainless steel, and nickel metal formed into a cylinder or plate shape, or metals such as aluminum, indium oxide, and tin oxide deposited or laminated on plastic or paper.

Example 1 An aluminum cylinder of 60φ×2601+1111 was prepared as a base.

Red red iron (ye2oa) lo o part (1 part, same hereinafter) is added to acrylic resin (trade name Niacridic A405).
, manufactured by Dainippon Ink Co., Ltd.) 80 parts (solid content 50%), melamine resin (trade name Varnish-Perbeckamine L121, manufactured by Dainippon Ink Co., Ltd.) 20 parts (solid content 60 inches), and 100 parts of toluene. solution and then dispersed in a ball mill for 6 hours. This dispersion was applied onto the above substrate by a dipping method and thermally cured at 150° C. for 30 minutes to form an intermediate layer with a thickness of 25 μm.

Next, copolymerized nylon resin (product name: Amilan C! M8
000, produced by Toshi) (by weight, hereinafter the same) was dissolved in a mixed solution of 60 parts of methanol and 40 parts of butanol, and the solution was dip coated onto the above intermediate layer to form a polyamide resin layer with a thickness of 1 μm.

Next, 10 parts of a disazo 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 1φ glass beads. 100 parts of methyl ethyl ketone was added to this dispersion, which was dip coated onto the polyamide resin layer, and dried by heating at 100''C for 10 minutes to form a charge generation layer with a coating weight of 0.1 f/fn2. .

Next, 10 parts of a hydrazone compound having the following structural formula and 15 parts of a styrene-methyl methacrylate copolymer resin (trade name: MS200; manufactured by Steel Manufacturing Co., Ltd.) were dissolved in 80 parts of toluene. This liquid was applied onto the charge generation layer and dried with hot air at 100'C for 1 hour to form a charge transport layer with a thickness of 16μ, thereby preparing an electrophotographic photoreceptor.

Example 2 The same substrate as in Example 1 was used. 80 parts of chromium permylene and 20 parts of tin oxide powder were mixed with 80 parts of acrylic resin (trade name: Niacridic A4o5, manufactured by Dainippon Ink Co., Ltd.).
(solid content 50%), 20 parts of melamine resin (trade name: Super Peccamin L121, manufactured by Dainippon Ink Co., Ltd.)
(solid content: 60%) and 100 parts of toluene, and then dispersed in a ball mill for 6 hours.

This dispersion was applied onto the substrate by dipping, and heated at 150°C for 3 hours.
Heat cured for 0 minutes to create a 25μ thick intermediate layer.

Next, the polyamide resin layer, charge generation layer, and charge transport layer used in Example 1 were sequentially formed to prepare an electrophotographic photoreceptor.

Comparative Example 1 An electrophotographic photoreceptor was prepared by sequentially forming the polyamide resin layer, charge generation layer, and charge transport layer used in Example 1 directly on the same substrate as in Example 1 without providing an intermediate layer. did.

The photoreceptors manufactured in Example 1.2 and Comparative Example 1 were
It is attached to an electrophotographic copying machine that has KV corona charging, image exposure, dry toner development, toner transfer to plain paper, cleaning process using a urethane rubber blade (hardness 70, pressure 106w72m, angle 20° to the photoconductor), etc. Gender was evaluated. Density 0.3 (Macbeth RD-5
A blue original having the spectral reflectance of the drawing was copied using a development setting that allows copying a 14-density measuring device (the same applies hereinafter) to a density of 0.5, and the density of each copy was measured.

As explained above, there is a gap of 520 n between the substrate and the charge generation layer.
By providing an intermediate layer containing a pigment that absorbs light with short wavelengths of less than m, it is possible to create an electrophotographic photoreceptor with good blue reproducibility.

[Brief explanation of drawings]

The drawing is a diagram showing the spectral reflectance of a blue original.

Claims (1)

[Scope of Claims] 1. In an electrophotographic photoreceptor having a charge generation layer and a charge transfer layer, a resin layer containing a colored pigment that absorbs short wavelength light of 520 nm or less is provided as an intermediate layer between the substrate and the photosensitive layer. An electrophotographic photoreceptor characterized by the following. 2. The electrophotographic photoreceptor according to claim 1, characterized in that a conductive white pigment is added to the colored pigment in order to lower the volume resistance of the intermediate layer.