JPH02203351A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body having a small residual potential by consisting an intermediate layer of a modified polyamide resin and consisting the modified polyamide resin essentially of specific copolymerized nylon. CONSTITUTION:The intermediate layer consists of the modified polyamide resin and the modified polyamide resin consists essentially of the 6 nylon in which 40 to 60mol% of amide bond consists of the substd. amide bond expressed by the formula I or the copolymerized nylon contg. the 6 nylon as its constituting component. In the formula I, X denotes an oxygen atom or sulfur atom; R denotes a methyl group, ethyl group, propyl group or butyl group. The volumetric resistance of the intermediate layer can, therefore, be controlled to a lower level by the function of the polar group substd. with the amide bond of the modified polyamide resin, by which the dependency of the electrophotographic characteristics on temp. and humidity is improved. The residual potential is lowered in this way and the electrophotographic sensitive body having the high sensitivity and long life is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic photoreceptor comprising a substrate, an intermediate layer and a photosensitive layer, and more particularly to an electrophotographic photoreceptor having an improved intermediate layer.

2. Description of the Related Art Conventionally, copying machines using an electrophotographic method are typified by micro printers, liquid crystal shutter one-way printers, LED printers, laser beam printers, etc., and are used in an electrophotographic latent image forming method. The electrophotographic photoreceptors used in these copying machines have the following disadvantages: 1) Large dark decay, poor charging characteristics, high residual potential, etc., which tends to reduce development contrast; 2) White spots, black spots, It is known that image defects called roughness, pinholes, etc. are likely to occur.

As a measure to solve these problems, attempts have been made to provide a resin layer between the substrate and the photosensitive layer with a thickness ranging from a few O1 to several tens of microseconds.

As the resin layer, for example, polyvaraxylene, casein,
Polyvinyl alcohol, phenolic resin, polyvinyl acetal resin, melamine resin, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, polyvinylpyridine, polyacrylic acid, polyester, polyvinylpyrrolidone, polyvinyl methyl ether, polystyrene,
Those formed from phenoxy resin, polyurethane, gelatin, various rubber resins, etc. are known.

Problems to be Solved by the Invention However, conventionally known resin layers can only improve some of the drawbacks of photoreceptors, or if environmental characteristics are taken into account, the effects are halved, making them technically extremely insufficient. I ran into something. For example, when nylon is used, it is difficult to apply because it dissolves only in special solvents such as formic acid, or the residual potential of the electrophotographic photoreceptor is high, resulting in a decrease in contrast potential and furthermore, It has drawbacks such as poor adhesion between photosensitive layers.

Further, for example, in Japanese Utility Model Application Publication No. 58-95351, N
-The use of alkoxymethylated nylon or N-alkylated nylon has been described, but although it has excellent charging properties, it has problems such as high residual potential or being susceptible to fluctuations due to long-term repeated use. ing.

As described above, in the conventional technology, as an undercoat layer that eliminates various drawbacks of electrophotographic photoreceptors,
The effect is still insufficient and the characteristics of the photoreceptor are unsatisfactory.

A first object of the present invention is to provide an electrophotographic photoreceptor that exhibits little dark decay, excellent charging characteristics, is less susceptible to deterioration in development contrast, and particularly has a small residual potential.

A second object of the present invention is to provide an electrophotographic photoreceptor in which image quality defects such as white spots, dark spots, roughness, and pinholes are less likely to occur.

A third object of the present invention is to provide an electrophotographic photoreceptor having electrophotographic properties with little environmental fluctuation and excellent durability.

Means and Effects for Solving the Problems The present invention provides an electrophotographic photoreceptor composed of a substrate, an intermediate layer, and a photosensitive layer, in which the intermediate layer is made of a modified polyamide resin, and the modified polyamide resin has a 7-mid bond of 40 ~
It is characterized in that it is mainly composed of 6-nylon or copolymerized nylon containing 6-nylon as a constituent component, in which 70 mol% is composed of substituted amide bonds represented by the following structural formula.

(X represents an oxygen atom or a sulfur atom, and R represents.

methyl group, ethyl group, propyl group or butyl group) The present invention will be described in detail below.

In the electrophotographic photoreceptor of the present invention, the intermediate layer is provided on the substrate, and any substrate known for electrophotographic photoreceptors can be used as the substrate.

The intermediate layer is composed of the above-mentioned modified polyamide resin.

The modified polyamide resin used in the present invention is made of 6-nylon or a copolymerized nylon containing 6-nylon as a component, for example, as described by Ding, L., Ca1rnS et al.
Chem, Soc, 71. pp651(1
949)) can be produced by modification according to a conventional method. The reaction proceeds as shown in the following formula, and the amide bond of nylon is replaced by a polar group.

NHCO-100H20+RXH NC0- CH2+H20 For example, a formic acid solution of nylon 6 or copolymerized nylon containing nylon 6 as a constituent is treated with an alcohol or mercaptan solution of formalin, and then poured into a non-solvent such as a water/acetone mixture. , neutralization with ammonia results in precipitation of the modified polyamide. Further, industrially, it can be produced by directly reacting formalin and alcohol or mercaptan on the above-mentioned hexasilon or copolymer nylon using a phosphoric acid catalyst at high temperature and high pressure.

As the degree of substitution of polyamide bonds increases, the crystallinity, melting point, and elastic modulus of the modified polyamide resin decrease, and the solubility and
Increased flexibility. On the other hand, the volume resistivity decreases further as the crystallinity decreases.

The degree of substitution can be selected within a wide range depending on the reaction conditions of the substitution reaction, but in the present invention, the degree of substitution is 40 to 7.
0 mol% is used. When the degree of substitution is lower than 40 mol%, it is difficult to satisfy the electrophotographic properties in terms of solvent solubility, adhesion, and volume resistivity;
When the degree of substitution is higher than 70 mol%, it becomes difficult to set reaction conditions. The type of substituent on the amide bond can be changed depending on the alcohol or mercaptan used in the modification reaction. When alcohol is used, for example,
Those having a methoxymethyl group, an ethoxymethyl group, an n-propoxymethyl group, an isobutoxymethyl group, etc., and when using a mercaptan, those having an ethylthiomethyl group, an isobutylthiomethyl group, etc. can be obtained. It will be done.

In the present invention, examples of the copolymerized nylon containing nylon 6 as a component to be modified include the following. As binary nylon, nylon 6-6 (Ube Nylon 2020B: manufactured by Ube Industries ■),
Nylon 6-66-610 (
Amilan C) 14000: Made by Toshi ■), Nylon 6-
66-12 (Diamide T171 and Diamid D250,: Daicel Hüls III, Ube Nylon 6
021X21: Ube Industries! Wooden, Bratabond H9
95F: Made by Nippon Rilsan N), Nylon 6-610-
12 (Diamide T451: Daicel Huls@W
A), nylon 6-66-bis(4-aminocyclohexyl)methane-6 (formerly tramtd IC: BASF
), Nylon 6-66-6 as quaternary nylon
10-12 (Amiran CH3000: manufactured by Toshi ■),
As special copolymer nylon, 11 series special copolymer nylon (Bratabond M1276T: manufactured by Nippon Rilsan ■),
Special copolymerized nylon (Bratabond HX1178, Bratabond HX1602 and Bratabond HX1603
: Nippon Rilsan (manufactured by tI).

In the present invention, the thickness of the intermediate layer is generally 0.01 to 5.
m1 is preferably set to 0.2 to 2 questions. In order to form the intermediate layer, it is necessary to prepare a coating solution, but as a solvent for dissolving the above-mentioned modified polyamide,
For example, alcohols such as ethanol, methanol, propatool, and butanol can be used alone or in combination, or as a mixture of these and water.

When applying the coating liquid, for example, dip coating method, spray coating method, blade coating method,
Coating methods such as spinner coating method, bead coating method, and curtain coating method can be used, and drying is carried out at 10 to 150°C, preferably 20 to 10°C.
5 minutes to 5 hours, preferably 10 minutes to 5 hours at a temperature in the range of 0°C
The drying can be carried out by blow drying or static drying for 2 hours.

In the electrophotographic photoreceptor of the present invention, the volume resistance of the intermediate layer can be controlled to a low level to the extent that the electrophotographic properties of the photosensitive layer do not deteriorate due to the function of the polar group substituted in the amide bond of the modified polyamide resin. can. Its volume resistivity is less dependent on temperature and humidity, and the temperature and humidity dependence of electrophotographic properties is improved.

A photosensitive layer is provided on the intermediate layer, and the photosensitive layer may have a single layer structure or a laminated structure. In the case of a single layer structure, a dye-sensitized ZnO photosensitive layer, a CdS photosensitive layer, a photosensitive layer in which a charge-generating substance is dispersed in a charge-transporting substance, etc. can be used.

Furthermore, in the case of a laminated structure, a charge generation layer and a charge transport layer may be separated in function. The charge generation layer and the charge transport layer may be stacked on the substrate in any order.

The charge generation layer is formed by dispersing a charge generation substance in a binder resin as required. Examples of the charge generating substance include selenium and selenium alloy: CdS.

Inorganic photoconductors such as CdSe, Cd5Se, ZnO and ZnS; Metal or non-metal phthalocyanine pigments: Azo pigments such as bisazo pigments and trisazo pigments; Squareium compounds; Azurenium compounds; Perylene pigments; Indigo pigments; Quinacridone pigments; Cyclic quinone pigments; cyanine dyes; xanthine dyes; charge transfer complexes made of poly-N-vinylcarbazole and trinitrofluorenone; and eutectic complexes made of pyrylium salt dyes and polycarbonate resins.

As the binder resin, well-known ones such as polycarbonate, polystyrene, polyester, polyvinyl butyral, methacrylic acid ester polymer or copolymer, vinyl acetate polymer or copolymer, cellulose ester or ether, polybutadiene, polyurethane, epoxy Resin etc. are used.

The charge transport layer is composed mainly of a charge transport substance.

The charge transfer substance is not particularly limited as long as it is transparent to visible light and has charge transport ability, and specific examples include imidazole, pyrazoline, thiazole, oxadiazole, and oxazole. , hydrazone, ketazine, azine, carbazole, polyvinylcarbazole, etc., and derivatives thereof, triphenylamine derivatives, stilbene derivatives, benzidine derivatives, etc. A binder resin is used in combination if necessary, and examples of the binder resin include polycarbonate, polyarylate, polyester, polystyrene, styrene-acrylonitrile copolymer, polysulfone, polymethacrylate ester, and styrene-methacrylate copolymer. Polymers etc. are commercially available.

Example Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 60-weight ffi part 6 nylon (product name: Tsuhe Nylon 1
013B, manufactured by Ube Industries viJ) 180 parts by weight 99
% phosphoric acid and stirred while maintaining at 60°C. On the other hand, 6
0 parts by weight of paraformaldehyde was dissolved in 60 parts by weight of methanol (to which a very small amount of potassium hydroxide was added in advance), and the solution maintained at 130'C was gradually added to the above nylon solution and stirred for 10 minutes. , reacted. next,
60 parts by weight of methanol was immediately added, and stirring was continued for an additional 20 minutes at 60°C. The obtained reaction solution was heated to 1700
mg of acetone-water mixture (volume ratio 1:1), and further, 28% ammonia water was added dropwise thereto to neutralize. As a result, a white powdery resin was precipitated. The resin was separated and washed repeatedly with water to remove excess ammonia.

1q of partially methoxymethyl-substituted 6-nylon was obtained with a degree of substitution of 44 mol%.

The obtained partially m-1-xymethyl-substituted 6-nylon was mixed with methanol/n-butanol/water (weight ratio 5:3:0.5).
A coating solution was prepared by dissolving it in a mixed solvent of 1 to give a solid content concentration of 10% by weight.

The above coating solution was applied onto an aluminum pipe using a dip coating method, and dried by heating at 100°C for 5 minutes, resulting in a film thickness of 0.
．． An intermediate layer of 51 IM was formed.

Next, 87 parts by weight of granular trigonal selenium and vinyl chloride-
Vinyl acetate copolymer (product name: Solution Vinyl Copolymer)
VMCH, manufactured by Union Carbide Co.) 13 parts by weight,
A solution prepared by dissolving 11 n-butyl vinegar in 200 parts by weight was subjected to a dispersion treatment using an attritor for 24 hours.

Next, 57 parts by weight of loubutyl acetate was added to 30 parts by weight of the resulting dispersion to dilute it to obtain a dip coating solution.

This dip coating solution was used to dip coat the intermediate layer on the aluminum pipe. That is, the aluminum pipe on which the intermediate layer has been formed is immersed in a coating solution in a dip coating tank, and 1
The sample was pulled up at a rate of 0.00 IrR/min, heated and dried at 100° C. for 5 minutes, and a charge generation layer having a thickness of about 0.1 μm was laminated.

Next, N,N'-diphenyl-N,N'-bis(3-
methylphenyl)-[1,1'-biphenyl]-4,4
'-10 parts by weight of diamine, 10 parts by weight of polycarbonate Z resin
Parts by weight were dissolved in 80 parts by weight of monochlorobenzene to prepare a coating solution for forming a charge transport layer. This coating liquid was applied onto the charge generation layer and dried with hot air at 100° C. for 60 minutes to form a charge transport layer having a thickness of 25#l.

The electrophotographic photoreceptor manufactured in this way is transferred to a copying machine (
Installed on the FX5030 modified machine (manufactured by Fuji Xerox ■),
After adjusting the dark potential V[) to be -aoo v, it was 28 rg/cI! Bright area potential V when given exposure of
L was measured. Thereafter, a durability test of 100,000 copies was conducted, and changes in dark potential VD and bright potential VL were measured. At the same time, image quality was evaluated.

The results are shown in Table 1.

Example 2 60 parts by weight of quaternary copolymerized nylon (6-66-610
-12 copolymerized nylon) (product name: Amilan C) 180
00, manufactured by Toshi Im) was dissolved in 180 parts by weight of a 99% formic acid-acetic anhydride (equal weight) mixed solution, and the mixture was maintained at 60°C and stirred. A partial methoxymethylation reaction was carried out in the same manner as in Example 1, except that this solution was used, to obtain a partially methoxymethyl-substituted copolymerized nylon having a degree of substitution of 46 mol%.

Using this material, an electrophotographic photoreceptor was prepared in the same manner as in Example 1, and evaluation was performed in the same manner. The results are shown in Table 1.

Example 3 60! Quantity of ternary copolymerized nylon (nylon 6-66
-bis(4-aminocyclohexyl)methane-6) (trade name: Ultramid IC, manufactured by BASF) at 1
It was dissolved in 50 parts by weight of 99% formic acid and stirred at air temperature. For dipping, 60 parts by weight of paraformaldehyde was gradually added to 120 parts by weight of sufficiently cooled ethyl mercaptan (in which a small amount of sodium hydroxide had been dissolved in advance) to dissolve it. The obtained paraformaldehyde-ethyl mercaptan solution was added to the above ternary copolymerized nylon solution. After stirring for about 1 hour and reacting, the reaction mixture was
The mixture was poured into 200 parts by weight of acetic acid and water (volume ratio 1:1), and 28% aqueous ammonia was added dropwise for neutralization. As a result, a white powdery resin was precipitated. After separation, washing with water was repeated to remove excess ammonia. The obtained partially methyl mercaptomethyl substituted copolymerized nylon had a degree of substitution of 50 mol%.

Using this product, an electrophotographic photoreceptor was produced in the same manner as in Example 1, and evaluated in the same manner. The results are shown in Table 1.

Comparative Example 1 Example 2 except that the intermediate layer was formed using copolymerized nylon that was not partially methoxymethylated.
An electrophotographic photoreceptor was prepared in the same manner as above, and evaluated in the same manner. The results are shown in Table 1.

Comparative Example 2 N-methoxymethylated nylon (partially N-methoxymethylated 6-nylon, degree of methoxymethylation: 30 mol%,
An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the intermediate layer was formed using Niresin F-30 (trade name) manufactured by Teikoku Kagaku Sangyo (manufactured by Teikoku Kagaku Sangyo (manufactured by No. 11)), and the electrophotographic photoreceptor was similarly evaluated. The results are shown in Table 1.

Effects of the Invention Since the electrophotographic photoreceptor of the present invention has an intermediate layer made of the above-mentioned components, the humidity dependence of development contrast is improved, the residual potential is reduced, and the electrophotographic photoreceptor has high sensitivity and a long life. The resulting copy image has an excellent effect in that image quality defects such as white spots, black spots, roughness, and pinholes are less likely to occur.

Patent applicant: Fuji Xerox Co., Ltd. Agent: Patent Attorney Tsuyoshi Watanabe

Claims (1)

[Claims] (1) In an electrophotographic photoreceptor composed of a substrate, an intermediate layer, and a photosensitive layer, the intermediate layer is made of a modified polyamide resin, and the modified polyamide resin has an amide bond of 40 to 70
1. An electrophotographic photoreceptor characterized in that its main component is 6-nylon or copolymerized nylon containing 6-nylon as a constituent component, with a mole percent of substituted amide bonds represented by the following structural formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (X represents an oxygen atom or a sulfur atom, R represents a methyl group, ethyl group, propyl group, or butyl group)