JPH0259458B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved electrophotographic photoreceptor,
Specifically, the present invention relates to a laminated electrophotographic photoreceptor provided with a photosensitive layer having a laminated structure consisting of a charge generation layer and a charge transport layer. polyvinylcarbazole, oxydiazole,
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. For this reason, several sensitization methods have been proposed, but it is known that an effective method is 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, and cellulose such as body phthalocyanine are dispersed in binder resins and formed by coating on a substrate. Something has been known for a long time. In that case, it is preferable to provide a resin layer on the substrate and apply the charge generation layer thereon, rather than directly coating the charge generation layer on the substrate. This resin layer is generally called a subbing layer or an intermediate layer, and 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 provides electrical protection for the photosensitive layer. It is provided for protection against destruction, improvement of carrier injection properties of the photosensitive layer, etc. Materials used for this undercoat layer include polyurethane, polyamide, polyvinyl alcohol, epoxy, ethylene-acrylic acid copolymer, ethylene-
Known examples include vinyl acetate copolymer, casein, methylcellulose, nitrocellulose, and phenolic resin. In addition, quaternary ammonium salts, sulfonates, etc. are known as conductive low-molecular compounds, but
When a subbing layer containing these conductive low-molecular compounds is formed, these conductive low-molecular compounds seep into the photosensitive layer provided on the subbing layer, causing defects in the photosensitive layer. , image defects such as black spots or white spots occur on the image. The material of such an undercoat layer greatly contributes to the sensitivity and durability of the photoreceptor, and the productivity of the photoreceptor. The present inventors investigated various materials for the undercoat layer and found that the characteristics are improved when the undercoat layer is made of a mixed system of polyamide resin and conductive polymer. In other words, increased sensitivity,
Sensitivity especially in low humidity environments has been improved. This is thought to be because the electrical resistance of the undercoat layer is reduced by mixing the conductive polymer with the polyamide resin, and the resistance value does not increase even in a low humidity environment. Furthermore, the durability of the photoreceptor has also been improved. The electrophotographic photoreceptor of the present invention has an undercoat layer made of a conductive polymer and a polyamide resin formed on a conductive substrate, a charge generation layer made of a binder resin with a pigment dispersed thereon, and a charge generation layer made of a binder resin with a pigment dispersed thereon. It is characterized by forming a charge transport layer. The present invention will be further explained below. The substrate may be any material as long as it has a conductive layer, such as aluminum, brass,
Metals such as stainless steel can be used, and polymer materials such as polyethylene terephthalate, polybutylene terephthalate, polyethylene, polypropylene, nylon, and polystyrene, and materials such as hard paper that have been subjected to conductive treatment can also be used. Examples of the conductive treatment method include a method of impregnating the above-mentioned insulator with a conductive substance, a method of laminating metal foil, and a method of providing a metal vapor deposition layer. Further, the shape of the base body can be cylindrical, film-like, foil-like, or the like. The polyamide resin used in the present invention is a linear polyamide, and is typified by so-called nylon and copolymerized nylon. In the present invention, since it is applied in the form of a solution, a low to 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 and 6-aminocaproic acid, which are raw materials for nylon 6, hexamethylene diamine and dicarboxylic acids such as adipic acid and sebacic acid, which are raw materials for nylon 66 and 610, and 11-, which is a raw material for nylon 11. Examples include aminoundecanoic acid, ω-laurolactam, which is a raw material for nylon 12, and 12-aminododecanoic acid, as well as bis(4-aminocyclohexyl)methane, metaxylylene diamine or its hydride, piperazine, 2,5- Diamines such as dimethylpiperazine and trimethylhexamethylene diamine may also be mentioned. N-methylated or N-methoxymethylated nylon is also useful in order to improve solubility. As the conductive polymer, an acrylic polymer type is generally used. Particularly effective are those having an anion group, a cation group such as a quaternary ammonium salt group, or a betaine group in the side chain. The amount of conductive polymer added to the polyamide resin is preferably 1 to 30 percent by weight. An undercoat layer can be formed by applying a coating liquid containing such a polyamide resin and a conductive polymer onto a substrate. The appropriate thickness of the undercoat layer is 1 to 10 microns. A charge generation layer is formed on this undercoat layer. The charge generating layer is applied after dispersing the aforementioned pigments in a binder resin (eg, polyvinyl butyral, polyester, polycarbonate, etc.). As for the dispersion method, the binder resin is dissolved using an appropriate solvent, the pigment is added thereto, and the dispersion can be carried out by 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. Further, as the charge generation layer, a pigment vapor deposition layer or an amorphous silicon layer formed by glow discharge can also be used. The charge transport layer coated on this charge generation layer contains polycyclic aromatic compounds such as anthracene, pyrene, phenanthrene, coronene, indole, carbazole, etc. in the main chain or side chain.
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 pyrazoline, thiadiazole, or triazole, or a hydrazone compound in a film-forming resin. 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 polyamide resin, which is a copolymerized nylon of nylon 6/66/610/12, was mixed with 60 parts of methanol and 30 parts of
A cationic acrylic polymer (product name: ELECOND) is dissolved in a mixed solvent of trichlene.
2 parts of PQ-10 (manufactured by Soken Kagaku) were added to prepare an undercoat layer coating solution. Apply the above coating solution to an 80φ x 360mm aluminum cylinder using the dipping method, and heat it at 100℃ for 10 minutes.
It was heated and dried for 1 minute to form a subbing layer with a thickness of 2 μm.
Next, 10 parts of a bisazo pigment with the following structural formula, 5 parts of polyvinyl butyral resin (product name: Eslex BM-1, manufactured by Sekisui Chemical), 40 parts of cyclohexanone, and 20 parts of methyl ethyl ketone were mixed into 1φ
A pigment dispersion was prepared by processing for 2 hours in a sand mill device using glass beads. This liquid was dip-coated onto the above-mentioned 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, 1-[pyridyl-(2)]-
3-(4-N,N-diethylaminostyryl)-5
- Applying 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 by a dipping method, It was dried by heating at 100° C. for 20 minutes to form a charge transport layer with a thickness of 12 μm. The obtained photoconductor is a photoconductor.
(). Example 2 A photoreceptor was produced in the same manner as in Example 1, except that an anionic polymer (trade name: Chemistat 6120, manufactured by Sanyo Chemical) was used as the conductive polymer.
This is referred to as photoreceptor-(). Example 3 10 parts of N-methoxymethylated nylon resin was dissolved in 70 parts of methanol and 20 parts of toluene, and cationic acrylic polymer (trade name: Elecondo) was dissolved in this.
1 part of PQ-10 (manufactured by Soken Kagaku Co., Ltd.) was added to prepare a subbing layer coating solution. On biaxially oriented polyethylene terephthalate film with aluminum vapor deposition,
The above coating solution was applied using a roll coater to form a subbing layer with a thickness of 3 μm. Next, 10 parts of a 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 and 40 parts of methyl isobutyl ketone,
Dispersion was carried out for 2 hours using a sand mill device using 1φ glass beads. Add 40% of methyl ethyl ketone to this dispersion.
A charge generating layer having a thickness of 0.2 μm was formed by applying the above undercoat layer using a roll coater. Next, 12 parts of hydrazone dye of the following structural formula, polyarylate resin (trade name: U-100, Unity) (manufactured by) 10 parts of monochlorobenzene and 50 parts of toluene
This solution was applied onto the charge generation layer to form a charge transport layer with a thickness of 15μ. In this manner, an electrophotographic photosensitive sheet is prepared, and this is used as a photoreceptor (). Comparative Example 1 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 a subbing layer, and this was used as a comparative photoreceptor. Measurement Electrophotographic photoreceptor () manufactured in Examples 1 to 3
-() and the comparative photoreceptor manufactured in Comparative Example 1 -
Electrophotographic copying that includes 5.6KV corona charging, image exposure, dry toner development, toner transfer to plain paper, cleaning process using a urethane rubber blade (hardness 70°, pressure 5gw/cm), angle 20° relative to photoreceptor), etc. It was installed on a machine and its characteristics were evaluated. Table 1
2 shows the initial sensitivity and the sensitivity after 3000 repeated durability tests.

[Table] As can be seen from Table 1, the electrophotographic photoreceptor of the present invention (photoreceptor~) has almost no decrease in sensitivity at low humidity, no deterioration in image quality after durability, and even in the appearance of the photoreceptor. No peeling of the layers was observed.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor characterized in that an undercoat layer containing a polyamide resin and a conductive polymer is provided between a conductive layer and a photosensitive layer.