JPH0243561A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the stability of a dark part potential at and under a high temp. and high humidity by incorporating the deriv. of polyglutamic acid or polyasparagine acid having a specific quaternary ammonium salt structure into an intermediate layer. CONSTITUTION:The polymer or copolymer having the monomer unit expressed by formula I is incorporated into the intermediate layer between a conductive base and a photosensitive layer. In formula I, (n) denotes 1, 2; A dentoes -COO-, -CONH-; Z denotes an alkylene group; Y<+> denotes the group selected from formula II; X<-> denotes an anion; in formula II, R2-R4 denote an alkyl group, phenyl group, etc.; B denotes a residual group forming a heterocycle together with N; D denotes a residual group forming a heterocycle together with N=C. The electrophotographic sensitive body with which the stable dark part potential is obtd. in spite of a change in the humidity and temp. condition is obtd. in this way.

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 having.

[Conventional technology]

In general, in Carlson-type electrophotographic photoreceptors, the stability of the dark area potential and bright S 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.

Up until now, polyamide (JP-A-46-47344, JP-A-52-25638), polyester (JP-A-52-20836, JP-A-54-1998) have been used between the photosensitive layer and the support.
No. 26738), polyurethane (JP-A-49-1004)
4, JP-A-53-89435), casein (JP-A-55-103556), polypeptide (JP-A-53-103556),
No. 48523), polyvinyl alcohol (%
No. 100240), polyvinylpyrrolidone (Japanese Patent Application Laid-Open No. 1973)
-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-106549)
No.), quaternary ammonium salt-containing polymer (JP-A-51-1
It is known to use an intermediate layer made of ethyl cellulose (Japanese Patent Application Laid-open No. 55-143564).

[Problem to be solved by the invention]

However, in electrophotographic photoreceptors using these materials as intermediate layers, the spot position tends to change due to the influence of the temperature and humidity environment, and the barrier function deteriorates under high temperature and humidity, making it difficult to inject carrier from the support side. There was a drawback that the dark area potential decreased and the density of the copied image became lighter.

Further, when all such photoreceptors are used in an electrophotographic printer that performs reversal development, there is a problem that capri is likely to occur in images 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 sequentially laminated, the charge generation layer containing a high concentration of a charge generation substance is located on the intermediate layer, which causes an increase in carrier injection from the support side. Even if the barrier function of the intermediate layer was slightly lowered, fogging was likely to occur in an IJ printer using a reversal development method.

Furthermore, photoreceptors using conventional materials for the intermediate layer tend to cause increases in bright area potential and fluctuations in dark area potential when used repeatedly, especially in low temperature, low humidity environments where the resistance of the intermediate layer is high. Since charges remain in the intermediate layer, the potential of the bright area increases significantly, and this 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 stable dark area potential against changes in temperature and humidity environment, and also to provide an electrophotographic photoreceptor that can increase the bright area potential and fluctuate the dark area potential even when used repeatedly. An object of the present invention is to provide an electrophotographic photoreceptor that suppresses .

[Means to solve the problem]

In the electrophotographic photoreceptor of the present invention, the intermediate layer between the conductive support and the photosensitive layer has the following formula: unit component ÷ Co -CH - booklet [where n is an integer of 1 or 2, and -coo- or -CONH-, 2 may be substituted and R4 is an alkyl group, phenyl group or pennol group, which may be substituted, and B is a residue forming a heterocycle with N; , D is a residue forming a heterocycle with N=C), and Xe is a barrier ion].

In the above polymer or copolymer used in the present invention, 2
is an alkylene group which may be substituted, and examples of substituents when substituted include a methyl group, a hydroxyl group, a methoxy group, a nitro group, a cyan group, and a halogen atom. When R2, R3 and R4 are substituted, the substituents include a hydroxyl group, a methoxy group, a nitro group,
There are cyano groups, halo, etc. Also, as an example of X00...
rn anion/, e e 20 2 (E)
C) ○PF , No , C
o, So, CFSO, CH3Co.

etc., but are not limited to these.

The polymer or copolymer used in the present invention has a degree of polymerization of 100 to
Preferably, it is in the range of 100,000.

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, rn
r ml and m2 represent the average degree of polymerization.

1゜Co-CH-■-Fuku- CH2 ÷Co-CH-NH-Fukuichi CH2 ÷Co-CH-NH+- 2゜6゜3゜-(-Co-CH-NH±T m”82.UIJ 8゜+Co-CH-NHu- 9゜÷Co-CH-朲一揄m=Z, j υ υ 10゜÷Co-CH-Nu← rn=9,200 CH, CH3 13゜m= 46, 000 CH2 H m=3,900 m=750 10+ 20°÷Co-CH-NH±i 21°÷Co-CM-NH← m=13,500 Quaternary ammonium salt contained in the intermediate layer in the present invention The above-mentioned amino acid visiting conductor having the structure is, for example, a polyglutamic acid ester having a dialkylamino group such as poly(γ-dialkylaminoalkyl-L-glutamate or poly(γ-dialkylaminoalkyl-L-asno Jl late)). Alternatively, it can be synthesized by reacting a polyas-yaragic acid ester with a quaternizing agent such as an alkyl halide or a dialkyl sulfate.

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, polyglobylene glycol, surfactants, and silicone leveling 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 Sudan Red, azo pigments such as Dia/Bruno Enus Gree/B, Algol Yellow, ♂ Renquinone, Indanthrene Brilliant Violet R
Charge-generating substances such as quino/pigments such as RP, quinocyanine pigments, perylene pigments, indigo pigments such as Innovo and Thioindigo, bisbenzimidazole pigments such as India First Orange Toner, 7-thalocyanine pigments such as copper phthalocyanine, and quinacridone pigments. It is dispersed in a binder resin such as polyvinyl butyral, polystyrene, polyvinyl chloride, divinyl acetate, acrylic resin, polyvinylpyrrolidone, methylcellulose, hydroxypropylmethylcellulose, and this dispersion is coated on the above-mentioned intermediate layer. It can be formed by The thickness of such a charge generation layer is 5μ or less, preferably 0.01 to 2μ.
It is.

The charge transport layer provided on the charge generation layer contains a polycyclic aromatic compound such as anthracene, pyrene, phenanthre/coronene, or indole, carbazole, oxazole, inoxazole, thiazole, imidazole, pyrazole, or oxazole in the main chain or side chain. It is formed using a coating liquid in which a charge-transporting substance such as a nitrogen-containing cyclic compound such as noazole, pyrazoline, thiadiazole, or triazole, a hydrazo/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 better film-forming properties include polyester,
Examples include polysulfone, polycarbonate, polymethacrylic acid esters, and Iristine.

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

In addition to those mentioned above, the photosensitive layer used in the present invention includes
Examples include an organic photoconductive polymer layer such as N-vinylcarbazole or polyvinyla/thracene, a selenium evaporation layer, a selenium-tellurium evaporation 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, aluminum, molybdenum, chromium, nickel, titanium, zinc,
Metal such as indium or brass formed into a drum or sheet shape, metal foil such as aluminum or copper laminated onto a glass film, aluminum, indium oxide, tin oxide, etc. deposited on a glass film, or , metal, glass film, paper, etc. in which a conductive layer is provided by applying a conductive substance alone or together with a suitable binder 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 inzoum oxide; polypyrrole, Examples include polymer conductive agents such as polyaniline polymer electrolyte; carbon fiber, carbon 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, IJ vinyl alkyl ether, polyvinyl alcohol,
N-vinylimidazole, alkyl cellulose, nitrocellulose, l 1,1 acrylic acid varnish, casein, gelatin, polyester, polyethylene oxide, polypropylene oxide, polyamino acid ester, polyvinyl acetate, polycargonate, Vinyl pyrrolidone, chloroglene rubber, nitrile rubber,
Thermoplastic resins and thermosetting polyurethanes such as polymethacrylic acid ester, polypeptide, polymaleic anhydride, polyacrylamide, polyvinyl formal, polyvinylpyridine, polyethylene glycol, polypropylene glycol, polyvinyl butyral, chlorosulfonated polyethylene, thermoplastic polyurethane, Examples include thermosetting resins such as phenol resins and epoxy 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.

If the conductive substance is a powder, use a ball 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 leveling agents, etc. may also be added.

Coating of the conductive layer is carried out by dip coating, spray 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.

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 by giving specific examples below.

〔Example〕

Example 1 50 parts of titanium oxide powder coated with tin oxide containing 10% antimony oxide, 25 parts of resol type phenolic resin
1 part, 20 parts of methyl cellosolve, 5 parts of methanol, and 0.1002 parts of silicone oil (dimethylpolysiloxane polyoxyalkylene copolymer, average molecular weight: 3500) were dispersed for 2 hours in a sand mill apparatus using 1 glass bead to form a conductive layer. A paint was prepared.

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, 5 parts of the above exemplary polymer AI was added to 95% dichloromethane.
A paint for the intermediate layer was prepared by dissolving the mixture in the following parts.

This solution was applied by dip coating on the conductive layer, and 1001:2
It was dried for 0 minutes to form an intermediate layer with a thickness of 1.0 μm.

Next, 10 parts of trisazo pigment with the structural formula, polymethyl methacrylate (
After dispersing 5 parts (average molecular weight = 11,000) and 60 parts of cyclohexanone in a Domill apparatus using 0.5φ glass beads for 5 hours, 120 parts of methyl ethyl ketone was added to prepare the dispersion. This dispersion was applied in an immersed amount on the above intermediate layer, dried at 80°C for 20 minutes, and
A charge generation layer was formed with a coating weight of p/-.

8 parts of styryl compound and 10 parts of polycarbonate (average molecular weight = 8,000) and 40 parts of dichloromethane,
This solution was dissolved in a mixed solvent of 20 parts of monochlorobenzene, and this liquid was dip-coated onto the above charge generation layer and dried at 120° C. for 50 minutes to form a charge transport layer with a thickness of 18 μm.

The electrophotographic photoreceptor manufactured in this way was attached to a Canon ■-Deglinter LBP-SX, and was used under normal temperature and normal humidity (22°C, 55% RH) and under high temperature and high humidity (34°C).
, 85% R, H) and found that this photoreceptor had a dark area potential (Vd) and a bright area potential (Vt).
), sufficient potential contrast is obtained, and the dark potential (Vd) is stable even under high temperature and high humidity.
A good image without black spots or capris was obtained. The results are shown in Table 1.

Example 2 As a paint for the intermediate layer, a paint prepared by dissolving 3 of the above-mentioned exemplary polymer in a mixed solvent of 60 parts of dichloromethane and 37 parts of 1,1.2.2-tetrachloroethane was used.
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 and evaluated in the same manner. The results are shown in Table 1.

Examples 3 to 6 As a paint for an intermediate layer, 6 parts each of the above-mentioned exemplified polymers or copolymers &4, 5, 11 and 15 were mixed with 9 parts of dichloromethane.
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the paint dissolved in 4 parts was used, and evaluated in the same manner. The results are shown in Table 1.

Comparative Example 1 An electrophotographic photoreceptor was manufactured in the same manner as in Example 1 except that a paint for the intermediate layer was prepared by dissolving 5 parts of the polymer having the structural formula in a mixed solvent of 50 parts of methanol and 45 parts of water. When similarly evaluated, under high temperature and high humidity conditions, the dark area potential (Va) decreased due to increased carrier injection from the support side, and capri was generated on the image. The results are shown in Table 1.

Example 7 A paint for an intermediate layer was prepared by dissolving 3 parts of the above exemplary polymer &6 in 97 parts of dichloromethane.

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 1.0 μm.

Next, 10 parts of the disazo pigment of the structural formula, 8 parts of butyral resin (degree of butyralization 69%, average molecular i: 19,000) and 60 parts of cyclohexanone'! ! After dispersing for 5 hours in a sand mill using -0.5φ glass beads, 120 parts of tetrahydrofuran was added to prepare a dispersion liquid, and the mixture was dip coated onto the above intermediate layer in a coating amount of 0.18 ji'/m2. A charge generation layer was formed.

Next, 10 parts of a hydrazone compound of the structural formula and styrene methyl methacrylate copolymer (styrene/methyl methacrylate = 8/
2. 10 parts of average molecular weight i 35,000 was dissolved in 80 parts of toluene. This liquid was dip-coated onto the charge generation layer and dried with hot air at 100° C. for 1 hour to form a charge transport layer with a thickness of 18 μm.

The electrophotographic photoreceptor manufactured in this way was attached to a Canon FC-5 copying machine under normal temperature and humidity (21°C, 6°C).
0°C) and high temperature and high humidity (33°C).

When the electrophotographic properties were evaluated at 854 RH), good images were obtained with no fluctuation in dark area potential even under high temperature and high humidity conditions. 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 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 intermediate 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.

Example 8 As a charge generating paint, 15 parts of sosazo pigment of the structural formula, 5 parts of polyvinyl butyral (molecular weight 24,000) and 50 parts of cyclohexanone were mixed into 1φ
After 3 hours of dispersion using a sand mill using glass beads,
An electrophotographic photoreceptor was prepared in the same manner as in Example 7, with an intermediate layer and a charge transport layer, except that a charge generation layer was formed using a paint prepared by adding 80 parts of methyl ethyl ketone.

The electrophotographic photoreceptor manufactured in this manner was attached to a Canon ■-Degree/Tar LBP-ST, and 1,000 images were continuously printed at low temperature and low humidity (10°C, 10% RH). A very stable image was obtained without any increase in bright area potential vt. The results are shown in Table 3.

Examples 9-10 4 parts of each of the above-mentioned exemplary polymers or copolymers 14 and 18 were added to 1.2-u chloroethane 9 as food for the middle layer.
An electrophotographic photoreceptor was prepared in the same manner as in Example 8, except that the paint dissolved in 6 parts was used, 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 bright area potential (Vt) increased and a decrease in image density was observed. The results are shown in Table 3.

Table 3: There was almost no increase, and the decrease in dark area potential under high temperature and high humidity conditions and the increase in bright area potential due to continuous use under low temperature and low humidity conditions, which were problems with conventional electrophotographic photoreceptors having an intermediate layer, were significantly improved. It has excellent environmental stability.

Agent: fP Yuyu Shimo 〔Effect of the invention〕

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 , n is an integer of 1 or 2, A is -COO- or -CONH-, and Z is optionally substituted C_
1 to C_6 is an alkylene group, and Y^■ has ▲ a mathematical formula, chemical formula, table, etc. ▼ or ▲ a mathematical formula, chemical formula, table, etc. ▼ (In this case, R_2, R_3 and R_4 are an alkyl group,
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 together with N=C, and X^■ is an anion.