JPS60218661A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To prevent fluctuation of electric resistivity due to change in humidity by using substd. polyacetylene soluble in org. solvents. for an underlayer. CONSTITUTION:Substd. polyacetylene is used as a single resin component of the underlayer to be formed between a substrate and a photosensitive layer. Since polyacetylene is insoluble in org. solvents, and it cannot be applied, substituents, such as phenyl, benzyl, methyl, methoxy, carboxy, dimethylsilyl, or amino, are introduced to use its solubilized substd. product. When its substitution product is high in electric resistivity, it is doped with I2 or AsF5 or the like to lower its resistivity. When another undercoat layer formed by dispersing a metal or pigment is used in addition, or mirror finishing is executed, this undercoat layer is formed in a thickness of 0.2-10mu and when not, in a thickness of 5-40mu.

Description

[Detailed description of the invention] The present invention relates to an electrophotographic photoreceptor having an undercoat layer.

An electrophotographic photoreceptor basically consists of a substrate and a photosensitive layer. However, improvements in adhesion between the substrate and 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, improvement of charge injection from the substrate to the photosensitive layer, etc. Therefore, it is effective to provide an undercoat layer between the substrate and the photosensitive layer.

Conventionally known materials for the undercoat layer include vinyl alcohol, polyvinyl methyl ether, poly-N-vinylimidasol, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, casein, gelatin, and polyamide.

The first characteristic required of the undercoat layer is electrical characteristics. Since it is used in an electrophotographic photoreceptor, it is important not to affect the electrophotographic properties, and for this purpose it is necessary to have low electrical resistance. If the electrical resistance is high, a charged potential will be applied to the undercoat layer, and a so-called residual potential will cause fogging on the image.

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, when the electrical resistance increases due to low humidity, fogging will occur.

Furthermore, when the electrical resistance decreases due to high humidity, white spots appear on the solid black image due to carrier injection.

The undercoat layer is required to have such properties, but it has been difficult to obtain good properties in the case of a single resin layer. Therefore, the thickness of the resin layer must be made very thin, or
Alternatively, if necessary, conductive powder (e.g., metal powder such as copper or silver) is dispersed in the resin. However, reducing the thickness of the resin layer has the disadvantage that its performance as an undercoat layer is insufficient.On the other hand, in the undercoat layer in which metal powder is dispersed, the metal particles are rough, so There was a drawback that the surface properties of the layer deteriorated.

An object of the present invention is to provide an electrophotographic photoreceptor that eliminates the above-mentioned drawbacks.

Another object of the present invention is to provide an electrophotographic photoreceptor having an undercoat layer that can substantially eliminate defects in a rough substrate.

Another object of the present invention is to provide an electrophotographic photoreceptor having a smooth surface between a rough substrate and a photoreceptor layer, and an undercoat layer that can be formed thickly.

The present invention relates to an electrophotographic photoreceptor comprising at least a support, an undercoat layer, and a photosensitive layer, wherein the undercoat layer is a substituted polyacetylene substance soluble in an organic solvent. .

That is, in the present invention, a polyacetylene substituted product is used as the undercoat layer resin in order to satisfy the above-mentioned conditions with a single resin layer. This is because polyacetylene obtained from acetylene monomer is insoluble in organic solvents and cannot be coated in the usual way.

However, since a polymer obtained by introducing a substituent into an acetylene monomer becomes soluble in an organic solvent, it can be coated. The substituents to be introduced include [phase], -CH2@, -CH3
, -C2H5, -C4H9, -C,5H9, -c 7C
H2, -'OCH3, -0C2H5, -C'OOH, -
COCH3, -H0CH2, -(CH3)58 i, -
(CH3)2 (c2H5o)si, -(CH5)2(
C3H70)Si, -NH2, -NHCH3, -N(C
H3)2 etc.

The electrical resistance of the substituted polyacetylene is two or more orders of magnitude higher than that of polyacetylene.

The electrical resistance required for the undercoat layer of an electrophotographic photoreceptor is not uniquely determined, but varies depending on the characteristics of the photosensitive layer coated on the undercoat layer, the applied exposure, and the charging process.

Therefore, if the electrical resistance of the polyacetylene substituted product is high for the applied photosensitive layer, exposure, and charging process,
By doping with sF5 or the like, it is possible to obtain a desired electrical resistance.

The thickness of the undercoat layer of the present invention is determined by the surface roughness of the substrate used,
It can be arbitrarily changed depending on the electrical resistance of the polyacetylene substituted product, the applied exposure, and the charging process.

In general, when using a substrate with a small surface roughness by applying another undercoating layer containing a metal or pigment dispersed therein or by performing mirror finishing, etc., the undercoat layer of the present invention is thin. On the other hand, when using a substrate with a large surface roughness without using any other undercoat layer, it is necessary to make the undercoat layer thicker.

In the former case, it is 0.2 to 10μ, preferably 0.5 to 5μ, and in the latter case, it is 5 to 40μ, preferably 10 to 30μ.
It is.

To explain the electrophotographic photoreceptor of the present invention in more detail, first, the substrate is made of metal such as aluminum, brass, or stainless steel, or polyethylene terephthalate, polybutylene terephthalate, phenol resin, polypropylene,
It is used by molding polymeric materials such as nylon and polystyrene, or materials such as hard paper into a cylindrical shape, or by making it into 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 is formed by coating dye-sensitized zinc oxide, selenium powder, amorphous silicon powder, polyvinyl carbazole, phthalocyanine pigment, oxadiazole pigment, etc. together with a binder resin as required.

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 is made of azo pigments such as Sudan, Red, Guianpoule, and Jenas Green B, quino/pigments such as Algol Yellow, Hirenquinone, and Indanthrene Brilliant Violet RRP, quinocyanine pigments, Thrylene pigments, indigo, thioindigo, etc. indigo pigment,
Charge-generating substances such as bisbenzimidazole pigments such as India Fast Orange toner, phthalocyanine pigments such as copper phthalocyanine, quinacridone pigments, and pyrylium-based dyes, polyester, polystyrene, polyvinyl acetate, acrylic, polyvinyl butyral, polyvinyl pyrrolidone, methyl cellulose, hydroxy It is formed by dispersing propyl methylcellulose and cellulose esters in a binder resin. Alternatively, it can also be formed by vapor deposition or the like. The thickness of the charge generation layer is 0.05-0.2μ
That's about it.

The charge transport layer may contain polycyclic aromatic compounds such as anthracene, herene, phenanthrene, coronene, etc., or indole, carfucisol, oxazole, isoxazole, thiazole, imidazole, pyrazole, oxadiazole, pyrazoline, thiadiazole, 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 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, polyester, styrene-acrylonitrile copolymer, polysulfone, and the like.

The thickness of the charge transport layer is approximately 5 to 20 microns.

Synthesis Example of Substituted Polyacetylene In a nitrogen gas atmosphere, 2 parts of MnC4 was added as a catalyst to 100 parts of phenylacetylene, and polymerization was carried out at -20°C for 2 hours. The reaction product was purified by dissolving it in THF and reprecipitating it in methanol.

The purified polyphenylacetylene was dissolved in THF,
A solution with a solid content of 20% was prepared.

Example 1 The polyphenylacetylene solution of the synthesis example was applied to a 50 μm thick aluminum sheet and dried at 100° C. for 20 minutes to prepare a sample for electrical resistance measurement.

Separately, add the polyphenylacetylene solution of the synthesis example to 6
100% by dipping method onto a 0σ aluminum cylinder.
Drying was carried out at ℃ for 20 minutes to obtain a 2μ undercoat layer.

Next, 10 parts of a disazo pigment having the following structural formula, 6 parts of cellulose acetate butyrate resin (trade name: CAB-381, manufactured by Eastman Chemical Company), and 60 parts of cyclohexanone were dispersed for 20 hours in a sand mill apparatus using 1σ glass beads.

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 generating layer with a coating amount of 0.197 m5.

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 Seitetsu Kagaku ■) were dissolved in 70 parts of toluene, and the solution was coated on the charge generation layer. 6 at 100℃
A charge transport layer having a thickness of 16 μm was formed by drying for 0 minutes, and an electrophotographic photoreceptor was prepared.

Comparative Example A sample for electrical resistance measurement and an electrophotographic photoreceptor obtained in the same manner as in Example 1 except that methyl cellulose resin (trade name: Metrose 5M-15) was used as the underlayer.

Samples for electrical resistance measurement of Example 1 and Comparative Examples were placed at room temperature and humidity (25°C, 60% RH) and at low temperature and low humidity (15°C, 1
The volume electrical resistivity was measured under an environment of high temperature and high humidity (325° C., 90 degrees RH). The results are shown in the table below.

In addition, the electrophotographic photoreceptors prepared in Example 1 and Comparative Example were -
5.5KV charging, image exposure, dry toner development, transfer to plain paper, then blade cleaning by pressing a urethane rubber blade with a thickness of 1fi and hardness of 70° at an angle of 30° with a pressure of 4PWh, using a copying machine. Image printing was performed under the above-mentioned environment. As a result, good quality images were obtained with the photoconductor of Example 1 in all environments, but with the photoconductor of Comparative Example, fogging occurred under low temperature and low humidity conditions, and solid black images were obtained under high temperature and high humidity conditions. White spots appeared.

Example 2 A photoreceptor obtained in the same manner as in Example 1 except that a polymethylacetylene solution was used instead of the polyphenylacetylene solution. - Example 3 A photoreceptor obtained in the same manner as in Example 1 except that a polybenzylacetylene solution was used instead of the polyphenylacetylene solution.

Example 4 A photoreceptor obtained in the same manner as in Example 1 except that a polydimethylamine acetylene solution was used instead of the polyphenylacetylene solution.

Images were produced using these photoreceptors in the same environment as the photoreceptor of Example 1, and as a result, images of good quality were obtained.

Patent applicant: Canon Co., Ltd. Agent: Patent attorney Yu Karino

Claims (1)

[Claims] (1) An electrophotographic photoreceptor comprising at least a support, an undercoat layer, and a photosensitive layer, wherein the undercoat layer is a polyacetylene substituted product soluble in an organic solvent.