JPH034904B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved laminated electrophotographic photoreceptor. polyvinylcarbazole, oxadiazole,
Organic photoconductive substances such as phthalocyanine contain selenium,
Compared to inorganic photoconductive materials such as cadmium sulfide, it has advantages such as being non-polluting and high productivity, but its low sensitivity has made it difficult to put it into practical use. Therefore, several sensitization methods have been proposed, and an effective method is known to use a functionally separated photoreceptor in which a charge generation layer and a charge transport layer are laminated. The charge generation layer is made of azo pigments such as Sudan Red, Diane Blue, and Jenas Green B; quinone pigments such as Algol Yellow, Pyrene Quinone, and Indanthrene Brilliant Violet RRP;
Indigo pigments such as quinocyanine pigments, perylene pigments, indigo and thioindigo, bisbenzimidazole pigments such as India First Orange Toner, phthalocyanine pigments such as copper phthalocyanine, and charge generating substances such as quinacridone pigments, polyester, polystyrene, polyvinyl chloride, polyvinyl acetate, acrylic, polyvinyl butyral,
It is conventionally known to form a material by dispersing it in a binder resin such as polyvinylpyrrolidone, methylcellulose, or hydroxypropylmethylcellulose and coating it on a substrate. In this case, it is preferable to provide a resin layer on the substrate and coat the charge generation layer thereon, rather than directly coating the charge generation layer on the substrate. This resin layer is generally called an undercoat layer or an intermediate layer, and it improves the adhesion between the photosensitive layer and the substrate, improves the coatability of the photosensitive layer, protects the substrate, covers defects on the substrate, and prevents electrical breakdown of the photosensitive layer. It is provided for the purpose of protecting the photosensitive layer, improving the chiaria injection property of the photosensitive layer, etc. These materials include polyurethane, polyamide, polyvinyl alcohol,
Known examples include epoxyethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, casein, methylcellulose, nitrocellulose, and phenolic resin. However, conventional undercoat layers have had the drawback of decreasing sensitivity under environmental conditions, particularly under low humidity environments. In addition, electrophotographic photoreceptors formed by forming an undercoat layer solely from an organometallic compound and further laminating a charge generation layer and a charge transport layer have the disadvantage of causing changes in potential characteristics, especially a decrease in sensitivity, when used repeatedly. It was hot. Therefore, the main object of the present invention is to provide an electrophotographic photoreceptor having an undercoat layer that solves these drawbacks. The present invention improves characteristics by applying a mixed system of a resin and an organometallic compound to the undercoat layer, that is, increases sensitivity, especially in a low humidity environment.
It also aims to improve the durability of the photoreceptor. The base material is metal such as aluminum, brass, stainless steel, polymeric material such as polyethylene terephthalate, polybutylene terephthalate, polyethylene, polypropylene, nylon, polystyrene, etc., or material such as hard paper, which is used as a cylindrical or film-shaped foil. In the case of a body, it is necessary to conduct conductive treatment, which can be done by impregnating it with a conductive substance, laminating metal foil, or depositing metal. An undercoat layer made of a mixed system of resin and organometallic compound is applied onto these substrates. Here, the resin can be appropriately selected from those that are not eluted by the solvent of the charge generation layer. For example, polyvinyl alcohol, gelatin,
Casein, cellulose, polyacrylic acid, polyacrylate, polyarylate, polystyrene, polyvinyl chloride, polyvinyl acetate, polyvinylpyrrolidone, polyester, polyamide, polycarbonate, styrene-maleic acid copolymer, styrene-methyl acrylate copolymer , and other various copolymer resins can be used. Furthermore, the organometallic compounds used in the present invention include Zn(CH ₃ ) ₂ , Zn(C ₆ H ₅ ) ₂ , Al(C ₂ H ₅ ) ₃ , B
Metal alkyl compounds such as (C ₂ H ₅ ) ₃ and Ni(C ₅ H ₅ ) ₂
There are metal alkoxides such as Al [OCH (CH ₃ ) ₂ ] ₃ and Ti (OC ₃ H ₇ ) ₄ , and there are also specialized metal chelate compounds, such as acetoacetic acid esters of chromium, vanadium, cobalt, iron, etc. Examples include chelate compounds, ethylenediamine chelate compounds, and carbonyl chelate compounds. Other organic carboxylic acid metal salts are also effective. These organometallic compounds are mixed with the aforementioned resin and a suitable solvent,
The undercoat layer coating solution is prepared as a homogeneous solution or, if necessary, in a dispersed state. As a dispersion method at this time, methods such as a roll mill, a ball mill, and a sand mill are used. The appropriate amount of the organometallic compound of the present invention to be added is 1 to 50 parts per 100 parts of the resin. The appropriate coating thickness of the undercoat layer is 0.5 to 10μ. A charge generation layer is formed on this undercoat layer. The charge generating layer is applied after dispersing the pigment described above in a binder resin. As for the dispersion method, the binder resin is dissolved using an appropriate solvent, the pigment is added thereto, and the pigment is dispersed using a method such as a ball mill, vibrating ball mill, sand mill, or roll mill. The coating thickness is preferably 0.1 to 1 μm. The charge transport layer coated on the main chain or side chain contains a polycyclic aromatic compound such as anthracene, pyrene, phenanthrene, coronene, or indole, carbazole, oxazole, isoxazole, thiazole, imidazole, pyrazole, oxadiazole, It is formed by dissolving a charge-transporting substance such as a compound having a nitrogen-containing cyclic compound such as pyrizoline, 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 polyester, polysulfone, polycarbonate, polymethacrylate, polystyrene, and the like. The thickness of the charge transport layer is suitably 5 to 20 microns. Next, the present invention will be further explained by showing specific examples. Example 1 10 parts of N-methoxymethylated nylon resin was dissolved in 70 parts of methanol and 20 parts of toluene, and 2 parts of triisopropoxyaluminum was added thereto to prepare an undercoat layer coating solution. The above coating solution was applied to an 80φ x 360mm aluminum cylinder by a dipping method and dried by heating at 80°C for 10 minutes to form an undercoat layer with a thickness of 2μ. Next, 10 parts of bisazo pigment with the following structural formula was used as a binder, A pigment dispersion was prepared by processing 5 parts of polyvinyl butyral resin (trade name: Eslex BM-1, manufactured by Sekisui Chemical), 40 parts of cyclohexanone, and 20 parts of methyl ethyl ketone in a sand mill using 1φ glass beads for 2 hours. This liquid was dip-coated onto the undercoat layer and dried by heating at 100° C. for 10 minutes to form a charge generation layer with a thickness of 0.2 μm. Next, place 1-[pyridyl-(2)]-3 on the charge generation layer.
-(4-N,N-diethylaminostyryl)-5-
A solution consisting of 10 parts of (4-N,N-diethylaminophenyl)pyrazoline, 10 parts of polysulfone resin (trade name: Udel p-1700, manufactured by UCC), and 70 parts of monochlorobenzene was applied by dipping to 100 parts.
The mixture was dried by heating at ℃ for 20 minutes to form a charge transport layer having a thickness of 12μ. The obtained photoreceptor is referred to as photoreceptor-(). Example 2 1 part of ethylmethylkabutotricarbonyl iron was added to 50 parts of a toluene solution (resin content 20 ^wt %) of methyl methacrylate-n-butyl methacrylate copolymer (molar ratio 7/3) to prepare an undercoat layer coating solution. make
Apply the above coating solution to an 80φ x 360mm aluminum cylinder by dipping method and dry at 80℃ for 10 minutes to obtain a film thickness of 3μ.
A subbing layer was formed. Next, 10 parts of bisazo pigment with the following structural formula was added to vinyl chloride-vinyl acetate copolymer (trade name: VMCH, manufactured by UCC) 5 parts, methyl ethyl ketone
20 parts of methyl isobutyl ketone and 40 parts of methyl isobutyl ketone were dispersed for 2 hours using a sand mill device using 1φ glass beads. Apply this solution on the undercoat layer by dipping at 100°C.
It was dried for 10 minutes to form a charge generation layer with a thickness of 0.15 μm. Next, 12 parts of a hydrazone dye having the following structural formula, 10 parts of polyarylate resin (trade name: V-100, manufactured by Unitika) was dissolved in 50 parts of monochlorobenzene and 50 parts of toluene, and this solution was coated on the charge generation layer to form a charge transport layer with a thickness of 15μ. formed. The obtained photoreceptor is referred to as photoreceptor-(). As a comparative photoreceptor, the charge generation layer and the charge transport layer in Example 1 were each formed on an aluminum cylinder without providing an undercoat layer, and this was used as a comparison photoreceptor. Photoconductor according to the present invention - Comparison with (), () Photoconductor -5.6kV corona charging, image exposure, dry toner development, toner transfer to plain paper, urethane rubber blade (hardness 70°, pressure 5gw/cm, photosensitive The characteristics were evaluated by attaching it to an electrophotographic copying machine that has a cleaning process at an angle of 20° with respect to the body. As shown in Table 1, the initial sensitivity and the sensitivity after 3000 repetitions of the durability test show that the photoreceptor of the present invention shows no decrease in sensitivity even in a low humidity environment and has good durability. Regarding image quality, good images were obtained even after repeated durability tests. 【table】

Claims (1)

[Claims] 1. A laminated electrophotographic photoreceptor comprising an undercoat layer, a charge generation layer, and a charge transport layer on a conductive substrate, the undercoat layer comprising an organometallic compound and a resin.