JPH0243560A - electrophotographic photoreceptor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more specifically, the present invention relates to an electrophotographic photoreceptor, and more specifically, the present invention relates to an electrophotographic photoreceptor, in which an intermediate layer having the function of both an adhesive layer and a barrier layer is provided between an electrically conductive support and a photosensitive layer. The present invention relates to an electrophotographic photoreceptor.

[Conventional technology]

In general, in Carlson-type electrophotographic photoreceptors, the stability of the dark area potential and bright area potential is important in forming images with constant image density and no background smudge when charging and exposure are repeated. .

For this reason, it has been proposed to provide a layer functioning as a barrier layer between the photosensitive layer and the support.

In addition, a layered structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has been proposed, but the charge generation layer is generally provided as an extremely thin layer, for example, with a thickness of about 0.5 μm. Defects, dirt, deposits, scratches, etc. on the surface of the support cause the thickness of the charge generation layer to be non-uniform. If the thickness of the charge generation layer is not uniform, uneven sensitivity will occur in the photoreceptor, so it is required that the charge generation layer be made as uniform as possible.

For this reason, it has been proposed to provide an intermediate layer between the charge generation layer and the support, which functions as a barrier layer and an adhesive layer.

Until now, polyamide (Japanese Patent Application Laid-open No. 4
6-47344, JP-A-52-25638), polyester (JP-A-52-20836, JP-A-54-2)
No. 6738), polyurethane (fP 1973-1004)
4, JP-A-53-89435), casein (JP-A-55-103556), polypeptide (JP-A-53-103556),
No. 48523), polyvinyl alcohol (Japanese Patent Application Laid-open No. 1983-
No. 100240), polyvinylpyrrolidone (Japanese Patent Application Laid-Open No. 1983)
-30936), vinyl acetate-ethylene copolymer (JP-A-48-26141), maleic anhydride ester polymer (JP-A-52-10138), polyvinyl butyral (JP-A-57-90639, JP-A-57-90639), Kaisho 58-106
No. 549), quaternary ammonium salt-containing polymer (Japanese Patent Application Laid-open No. 5
It is known to use an intermediate layer made of ethyl cellulose (Japanese Patent Application Laid-open No. 1-126149, JP-A-56-60448), ethyl cellulose (JP-A-55-143564), or the like.

[Problem to be solved by the invention]

However, in electrophotographic photoreceptors using these materials as intermediate layers, the potential tends to change due to the influence of the temperature and humidity environment, and under high temperature and humidity, the barrier function decreases and the dark area potential increases due to carrier injection from the support side. There was a drawback that the density of the copied image was reduced.

Furthermore, when such a photoreceptor is used in an electrophotographic printer that performs reversal development, there is a problem in that images tend to become foggy under high temperature and high humidity conditions.

In particular, in a laminated electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are laminated one after another, the charge generation layer containing a high concentration of a charge generation substance is located on the intermediate layer, so carrier injection from the support side increases. Therefore, even if the barrier function of the intermediate layer was slightly reduced, capri was more likely to occur in printers using a reversal development system.

Furthermore, photoreceptors using conventional materials for the intermediate layer tend to have an increase in bright area potential and a fluctuation in dark area potential when used repeatedly.Especially in low temperature and low humidity environments where the resistance of the intermediate layer increases, Due to the residual charge, the bright area potential increases significantly, and it has the disadvantage that copies with a constant image quality cannot be obtained when used continuously.

An object of the present invention is to provide an electrophotographic photoreceptor that can obtain a constant dark potential despite changes in temperature and humidity environment, and
It is an object of the present invention to provide an electrophotographic photoreceptor that suppresses increases in bright area potential and fluctuations in dark area potential even when used repeatedly.

[Means to solve the problem]

In the electrophotographic photoreceptor of the present invention, when the unit component R4 is substituted in the intermediate layer between the conductive support and the photosensitive layer, the substituents include a hydroxyl group, a methoxy group, a nitro group, a cyan group, and a cyan group. 1 [In the ceremony,
R1 is a hydrogen atom or a methyl group, A is an optionally substituted C1-C6 alkylene group, and R2, R3, and R4 are an alkyl group, a phenyl group, or a benzyl group, which may be substituted. B is a residue that together with N forms a heterocycle; It is characterized by

In the above polymer or copolymer used in the present invention, A
is an alkylene group which may be substituted, and examples of the substituent when substituted include a methyl group, a hydroxyl group, a methoxy group, a nitro group, a cyano group, and a halodane atom. R2, R3 and ha cr l' 7 anions,
BF4CLO4CH3SO3eCF Soo CH3C
Examples include OO°, but are not limited to these.

Next, specific examples of the polymer or copolymer used for the intermediate layer in the present invention are shown below. In the description of those specific examples, n, n
and R2 represents the average degree of polymerization.

In the present invention, the above-mentioned polymer or copolymer having a quaternary ammonium salt structure contained in the intermediate layer is, for example, P-epoxyethylphenyl acrylic acid or methacrylic acid. Synthesizing an acrylic ester monomer or methacrylic ester monomer containing a quaternary ammonium salt from ester trialkylamine hydrochloride, etc., and then polymerizing this or copolymerizing this with other copolymerizable monomers. It can be synthesized by

In the present invention, the intermediate layer can be composed of the above-mentioned polymers or copolymers alone, a mixture of two or more thereof, or a mixture of them and other resins or additives. Examples of other resins and additives include copolymerized nylon resin, N-methoxymethylated nylon resin,
Examples include polyvinylpyrrolidone, polyacrylamide, polyvinyl butyral, polypropylene glycol, surfactants, and silicone reperinda agents.

In the present invention, the thickness of the intermediate layer is 0.1 to 10.0μ.
, particularly preferably 0.5 to 5.0 μm, and is applied by dip coating, spray coating, roll coating, or other methods.

In the present invention, the photosensitive layer may be of a single type or may be of a laminated structure type in which the functions are separated into a charge generation layer and a charge transport layer.

The charge generation layer is composed of azo pigments such as Sudan Red and Diane Progenus Green B, quinone pigments such as Algol Yellow Pyrenequinone, Indanthrene f IJ IJ Anthoviolet RRP, quinocyanine pigments, perylene pigments, indib pigments such as Indigo and Thioindigo, and Indian pigments such as Indigo and Thioindigo. Bispen imidazole pigments such as Fast Orange Toner, 7-thalocyanine pigments such as steel phthalocyanine, charge-generating substances such as quinacridone pigments, 4-vinyl petyral, polystyrene, polyvinyl chloride, polyvinyl acetate, acrylic resin, polyvinylpyrrolidone,
It can be formed by dispersing it in a binder resin such as methylcellulose or hydroxypropylmethylcellulose, and coating this dispersion on the above-mentioned intermediate layer. The thickness of such a charge generation layer is 5μ or less, preferably 0.0μ.
It is 1 to 2μ.

The charge transport layer provided on the charge generation layer has a main chain or a side chain containing a polycyclic aromatic compound such as anthracene, pyrene, phenanthrene, coronene, or indole, carbazole, oxazole, isoxazole, thiazole, imidazole, pyrazole, It is formed using a coating liquid in which a charge-generating substance such as a nitrogen-containing cyclic compound such as oxadiazole, pyrazoline, thiadiazole, or triazole, a hydrazone compound, or a styryl compound is dissolved in a resin having film-forming properties. The reason why it is formed in this way is that the charge transporting substance generally has a low molecular weight and has poor film-forming properties by itself.

Examples of resins with such film-forming properties include polyester,
Examples include polysulfone, polycarbinate, polymethacrylic acid esters, polystyrene, and the like.

The thickness of the charge transport layer is 5 to 40μ, preferably 10 to 25μ
μ.

In addition to the above-mentioned photosensitive layers used in the present invention, organic photoconductive polymer layers such as yle-N-vinylcarbazole and polyvinylanthracene, selenium evaporated layers, selenium-
Examples include a tellurium vapor deposited layer or an amorphous silicon layer.

If the support used in the present invention has conductivity,
Any material may be used, such as aluminum, copper, vanadium, molybdenum, chromium, nickel, titanium, zinc,
Metals such as indium and brass molded into drums or sheets, metal foils such as aluminum and copper laminated onto glass films, aluminum, indium oxide, tin oxide, etc. deposited on plastic films, or Examples include metal, plastic film, paper, etc. in which a conductive layer is provided by applying a conductive substance alone or together with a suitable inder resin.

The conductive substances used in this conductive layer include metal powders, metal foils, and short metal fibers such as aluminum, copper, nickel, and silver; conductive metal oxides such as antimony oxide, tin oxide, and indium oxide; polypyrrole, Examples include polymer conductive agents such as polyaniline and polymer electrolytes; carbon fiber curd black, graphite powder; organic and inorganic electrolytes; and conductive powder whose surface is coated with these conductive substances.

In addition, as the binder resin of the conductive layer, polyvinyl alcohol, polyvinyl alkyl ether, yN Li-N
-k'nylimitasol, alkylcellulose, nitrocellulose, polyacrylic acid ester, casein, gelatin, polyester, polyamide, -lyethylene oxide, polypropylene oxide, polyamino acid ester, polyvinyl acetate, polycarbanate, polyvinylpyrrolidone, chloroprene rubber, nitrile Rubber, polymethacrylate ester, I? Thermoplastic resins such as lyzotide, polymaleic anhydride, polyacrylamide, polyvinyl formal, polyvinylpyridine, polyethylene glycol, polypropylene glycol, polyvinyl butyral, chlorosulfonated polyethylene, thermoplastic polyurethane, thermosetting polyurethane, phenolic resin, epoxy resin, etc. Examples include thermosetting resins.

The mixing ratio of the conductive substance and the binder resin is 5:1 to 1:
It is about 5. This ratio is determined by considering the resistance, surface properties, coating suitability, etc. of the conductive layer.

When the conductive substance is powder, sol mill, roll mill,
A mixture is prepared and used in a conventional manner using a sand mill, attritor, etc.

In addition, other additives include surfactants, silane coupling agents, titanate coupling agents, silicone oil,
Silicone oil/agent may be added.

The conductive layer is applied by dip coating, gray coating, roll coating, etc., and the film thickness is approximately 0.5 to 30μ, taking into consideration the degree of defects and scratches on the support and the electrophotographic characteristics. It can be decided by

Further, the electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines but also for laser printers.
It can be used for RT printers, electrophotographic plate making systems, etc.

The present invention will be explained in more detail with reference to specific examples below.

〔Example〕

Example 1 50 parts of titanium oxide powder coated with tin oxide containing 10 parts of antimony oxide, 25 parts of phenol resin
parts, 20 parts of methyl cellosolve, 5 parts of methanol, and silicone oil (dimethylpolysiloxane polyoxyalkylene copolymer, average molecular weight: 3500) 0.002
The mixture was dispersed for 1 hour using a sand mill using 1φ glass beads to prepare a coating material for a conductive layer.

The above paint was applied by dip coating onto a 30φ aluminum cylinder and dried at 140° C. for 30 minutes to form a conductive layer with a thickness of 20 μm.

Next, 8 parts of the above Exemplary Polymer Point 1 were dissolved in 92 parts of methanol to prepare a paint for the intermediate layer.

This solution was applied by dip coating onto the above conductive layer and heated to 100°C for 15 minutes.
It was dried for a minute to form an intermediate layer with a thickness of 1.2 μm.

Next, 10 parts of trisazo pigment of the structural formula, polymethyl methacrylate (
After dispersing 5 parts (average molecular weight: 11,000) and 60 parts of cyclohexanone in a sand mill apparatus using 0.5φ glass beads for 5 hours, 120 parts of methyl ethyl ketone was added to prepare a dispersion. This dispersion was dip coated onto the above intermediate layer, dried at 80°C for 20 minutes, and
,! A charge generation layer was formed with a coating amount of i'/m2.

8 parts of styryl compound and 10 parts of polycarzenate (average molecular weight: 8,000) were dissolved in a mixed solvent of 40 parts of dichloromethane and 20 parts of monochlorobenzene, and this solution was applied by dip coating onto the charge generation layer. It was dried at .degree. C. for 50 minutes to form a charge transport layer with a thickness of 20 .mu.m.

The electrophotographic photoreceptor manufactured in this manner was attached to a Canon Co., Ltd. Zergriinter LBP-SX.
When the electrophotographic properties of this photoreceptor were evaluated at room temperature and humidity (22°C, 55% RH) and at high temperature and high humidity (32°C, 85% RH), it was found that this photoreceptor had a dark area potential (Vd) and a bright area potential ( V2), sufficient potential contrast was obtained, the dark area potential (Vd) was stable even under high temperature and high humidity, and good images without black spots and capri were obtained.

The results are shown in Table 1.

Example 2 Electrophotographic exposure was carried out in the same manner as in Example 1, except that 10 parts of the exemplified copolymer A5 dissolved in a mixed solvent of 60 parts of methanol and 30 parts of water was used as the intermediate layer paint. A body was created and evaluated in the same manner.

The results are shown in Table 1.

Examples 3 to 6 As a paint for an intermediate layer, 15 parts of each of the above exemplary polymers or copolymers &2, 6, 13 and 16 were mixed with 85 parts of methanol.
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the paint dissolved in the sample was used, and evaluated in the same manner. The results are shown in Table IK.

Comparative Example 1 An electrophotographic photoreceptor was manufactured in the same manner as in Example 1 except that a paint dissolved in a structural solvent mixture was used as the paint for the intermediate layer, and evaluated in the same manner. Due to the increase in carrier injection, the dark potential (Vd) decreased and a capri was generated on one image.

The results are shown in Table 1.

Mixing 5 parts of the polymer shown in Table 1 with 50 parts of methanol and 45 parts of water Example 7 A paint for an intermediate layer was prepared by dissolving 10 parts of the exemplified polymer &4 in 90 parts of methanol.

This intermediate layer coating material was applied by dip coating onto a 30φ aluminum cylinder serving as a conductive support, and dried at 100° C. for 20 minutes to form an intermediate layer having a thickness of 0.7 μm.

Next, 10 parts of the disazo pigment with the structural formula, 8 parts of butyral resin (degree of butyralization, 69 degrees, average molecular weight 19,000), and 60 parts of cyclohexanone were dispersed for 5 hours in a sand mill using 0.5φ glass beads, and then dispersed in tetrahydrofuran. 120
A dispersion was prepared by adding 0.181 parts m<2> to form a charge generating layer by dip coating on the intermediate layer.

Next, 10 parts of a hydrazone compound of the structural formula and styrene-methyl methacrylate copolymer (styrene/methyl methacrylate =
8/2, average molecular weight 35,000) was dissolved in 80 parts of toluene. This solution was dip-coated onto the charge generation layer, dried with hot air at 100°C for 1 hour, and coated with a 20μ
A thick charge transport layer was formed.

The electrophotographic photoreceptor manufactured in this manner was attached to a copier FC-5 manufactured by Canon Co., Ltd. under normal temperature and humidity (21°C).
, 60℃ RH) and high temperature and high humidity (33℃, 85%RH)
), the electrophotographic properties were evaluated, and it was found that there was no change in dark area potential even under high temperature and high humidity, and good images were obtained. The results are shown in Table 2.

Comparative Example 2 An electrophotographic photoreceptor was prepared in the same manner as in Example 7, except that as the paint for the intermediate layer, a paint prepared by dissolving 6 parts of the polymer of the structural formula in 94 parts of methanol was used as the paint for the structural charge generation layer. ,
As a result of evaluation, it was found that under high temperature and high humidity conditions, the dark area potential decreased due to increased carrier injection from the conductive support, and the image density decreased. The results are shown in Table 2.

15 parts of cis-sazo pigment in Table 2, polyvinyl butyral (molecule!
24,000) and 50 parts of cyclohexanone in 1
An intermediate layer and a charge transport layer were provided in the same manner as in Example 7, except that a charge generation layer was formed using a paint prepared by adding 80 parts of methyl ethyl ketone after φ was dispersed for 3 hours in a sand mill device using lath beads. An electrophotographic photoreceptor was created.

When the electrophotographic photoreceptor manufactured in this manner was attached to a laser printer LBP-ST manufactured by Canon Co., Ltd. and 1,000 images were printed continuously at low temperature and low humidity (10°C, 104RH), bright areas were detected. A very stable image was obtained without any increase in potential (VZ). The results are shown in Table 3.

Examples 9 to 10 Electrophotographic exposure was carried out in the same manner as in Example 8, except that 15 parts of each of the above-mentioned exemplary polymers and copolymers 17 and 21 were dissolved in 85 parts of methanol as paints for the intermediate layer. A body was created and evaluated in the same manner. The results are shown in Table 3.

Comparative Example 3 An electrophotographic photoreceptor was prepared in the same manner as in Example 8, except that the paint used in Comparative Example 1 was used as the intermediate layer paint, and evaluated in the same manner. The partial potential (VZ) increased and the image density decreased. The results are shown in Table 3.

Table 3 [Effects of the Invention] The electrophotographic photoreceptor of the present invention contains an acrylic ester or methacrylic ester polymer or copolymer having a quaternary ammonium salt structure as shown in the claims in the intermediate layer. As a result, there is almost no decrease in barrier function under high temperature and high humidity conditions, and almost no increase in resistance under low temperature and low humidity conditions, and a decrease in dark area potential under high temperature and high humidity conditions, which was a problem with conventional electrophotographic photoreceptors with intermediate layers. It has excellent environmental stability and has significantly improved bright area potential increase due to continuous use under low temperature and low humidity conditions.

Claims (1)

[Scope of Claims] 1. In an electrophotographic photoreceptor having a conductive support, a photosensitive layer, and an intermediate layer between them, the intermediate layer is a unit component ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula , R_1 is a hydrogen atom or a methyl group, A is an optionally substituted C_1 to C_6 alkylene group, and Y^■ is ▲ has a mathematical formula, chemical formula, table, etc. ▼ or ▲ has a mathematical formula, chemical formula, table, etc. Yes▼ (In this case, R_2, R_3 and R_4 are alkyl groups,
a phenyl group or a benzyl group, which may be substituted, B is a residue that forms a heterocycle with N,
D is a residue forming a heterocycle with N=C_, and X^■ is an anion.