JP2631028B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor, and more particularly, to an organic charge transport material on a photosensitive layer containing a polysilane compound which gives improved electrophotographic properties. The present invention relates to an electrophotographic photoreceptor having a surface layer composed of a resin layer containing

[Description of Prior Art]

Conventionally, as an organic photoconductive material used for an electrophotographic photoreceptor, various organic photoconductive polymers including polyvinyl carbazole have been proposed. Despite their superiority in film-forming properties and lightness compared to inorganic photoconductive materials, these polymers have been difficult to put to practical use until today because they still have sufficient film-forming properties. This is because they are inferior to inorganic photoconductive materials in sensitivity, durability and stability against environmental changes. In addition, as an organic photoconductive material for an electrophotographic photoreceptor, U.S. Pat.
No. 987 describes hydrazone compounds as disclosed in U.S. Pat.
No. 37,851 proposes a triarylpyrazoline compound, and JP-A-51-94828 or JP-A-51-94829 proposes a 9-styrylanthracene compound, respectively, which are of low molecular weight. However, all of these low-molecular organic photoconductive materials do not solve the problem of the film forming property which is a problem in the field of organic photoconductive polymers by properly selecting the binder to be used. Although there is not enough in terms of sensitivity,
It is not practically practical to obtain a desired electrophotographic photoreceptor.

For these reasons, a laminated structure in which a photosensitive layer is separated from a charge generation layer and a charge transport layer in function has recently been proposed.
An electrophotographic photoreceptor having this laminated structure as a photosensitive layer can be improved in terms of sensitivity to visible light, charge retention, surface strength, and the like. Such electrophotographic photoreceptors are described, for example, in U.S. Patent Nos. 3,837,851 and 3,837,851.
It is disclosed in the specification of 71,882 and the like.

However, when producing the charge transport using a conventional low-molecular organic photoconductive material, the organic photoconductive material is used in any case by being mixed with a predetermined binder resin. For this reason, the obtained electrophotographic photoreceptor has low charge mobility, sensitivity and characteristics are not always sufficient due to the binder resin, and when a repetitive charging and exposure is performed, a bright portion potential and a dark portion potential are reduced. Fluctuations are large, resulting in insufficient durability.

For these reasons, polysilane has attracted attention as a photoconductive material that may provide a desired organic electrophotographic photoreceptor.

By the way, it has been reported that so-called polysilanes are insoluble in solvents, but [The Journal of American Chemical Society (The Journal)
of American Chemical Society) 125 , 2291pp (1924)
In recent years, it has been reported that polysilane is soluble in a solvent and can form a film. [The Journal of American Ceramic Society, 61 , 5
04pp (1978)].

In addition, it has been reported that polysilane has the property of an optical semiconductor capable of transferring charges by a σ-bond of the main chain [Physical Review (Physical Revie).
w), B 35 , 2818 pp (1987)].

For these reasons, application of polysilane to photoconductors for electrophotography is expected.However, in order to obtain desired electrophotographic photoconductors that can be practically used by using polysilane as a photoconductive material, the following polysilanes are used. It is required to satisfy at least such requirements. That is, those requirements are that (i) not only solvent-soluble and film-forming ability, but also formation of a film without fine defects and formation of a film with high homogeneity are possible, (ii)
In the electrophotographic photoreceptor, since fine defects are not allowed, the structure of the substituent is clear, and the substituent is of high quality which does not cause an abnormality in film formation.

Further, polysilane is known to be capable of forming a relatively durable film, but when applied to an electrophotographic photoreceptor, the surface of the polysilane gradually becomes brittle due to repeated charging and exposure, and the surface of the polysilane is gradually reduced. There is also a problem that the image may be shaved by the cleaning blade to cause an image defect in an image to be formed.

[Object of the invention]

An object of the present invention is to solve the above-mentioned problems and to provide an electrophotographic photoreceptor excellent in sensitivity, durability and moldability.

[Configuration of the invention]

The present invention achieves the above-mentioned object, and the electrophotographic photoreceptor provided by the present invention is an electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer has a charge generation property. A layer of a polysilane compound represented by the following general formula laminated on the layer and the charge generation layer, and
The photosensitive layer has a surface layer composed of a resin layer containing an organic charge transporting substance.

Wherein R ₁ is an alkyl group having 1 or 2 carbon atoms, R ₂ is an alkyl group having 3 to 8 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group, and R ₃ is an alkyl group having 1 to 4 carbon atoms. And the group R ₄ represents an alkyl group having 1 to ₄ carbon atoms. A and A 'each represent an alkyl group having 4 to 12 carbon atoms;
It is a cycloalkyl group, an aryl group or an aralkyl group, both of which may be the same or different. Each of x and y represents a monomer polymerization unit. The configuration of the electrophotographic photoreceptor of the present invention is shown in FIGS.
Illustrated in the figure.

FIG. 1 shows that a charge generation layer 3 is provided on a conductive substrate 4,
Next, a polysilane layer 2 is provided, and a surface layer 1 made of a resin containing an organic charge transporting material is further provided. FIG. 2 shows a conductive substrate 4 and a charge generation layer 3 in FIG. The undercoat layer 5 is provided between them.

In the electrophotographic photoreceptor of the present invention having the above structure, the charge transfer from the charge generation layer 3 to the polysilane layer 2 is remarkably fast, and the surface layer 1 is not a mere protective layer but a layer containing an organic charge transport material. Does not reduce light sensitivity. In addition, since the surface layer 1 is not a brittle polysilane layer but an organic charge transporting layer from which various binders can be selected, a binder having necessary mechanical properties can be appropriately selected. That is, the electrophotographic photoreceptor of the present invention can provide a photoreceptor having remarkably high sensitivity and durability, excellent adhesiveness, and excellent wear resistance.

The conductive support of the electrophotographic photoreceptor of the present invention will be described. First, the shape may be any shape such as a cylindrical shape, a belt shape, and a plate shape. Next, the constituent material may be a member that is entirely conductive, or a member in which the base is an insulating member and the surface on which the light receiving layer is provided is subjected to a conductive treatment. Specific examples of the former case, for example, aluminum, copper, metal members such as zinc, aluminum alloys, and alloys such as stainless steel, for the latter case, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, A member in which a coating of the above-described metal is formed on a surface of a plastic base member such as an acrylic resin by a known vacuum evaporation method, and conductive particles such as titanium oxide, tin oxide, carbon black, and silver are formed on the surface of the plastic base member. A member coated with an appropriate binder resin, a member in which the conductive particles are impregnated into an impregnable base member such as paper or plastic, and the like can be given. In addition to these members, a member in which the surface of a suitable metal base member is coated with the conductive particles using a suitable binder resin can also be used as the conductive support.

Next, the charge generation layer 3 of the present invention will be described. The charge generation layer 3 used in the present invention comprises 6 len, selenium-tellurium,
Inorganic charge-generating substances such as amorphous cis-con, pyrylium-based dyes, thiapyrylium-based dyes, azurenium-based dyes, thiocyanine-based dyes, cation dyes such as quinocyanine-based dyes, azurenium-based dyes, etc. Pigment, a material selected from organic charge generating substances such as polycyclic quinone pigments such as dibenzopyrene quinone pigments and pyranthrone pigments, isodigo pigments, quinacridone pigments, and azo pigments, singly or in combination. Alternatively, it can be used as a coating layer.

Among the above-mentioned charge generating substances used in the present invention, in particular, azo coatings are diversified. Representative structural examples of azo pigments having particularly high effects are shown below.

As a general formula of the azo pigment, if indicated the central skeleton as follows A, the AN = N-C _{P) n} Gapura portion as C _P (where n = 2or3),
First, specific examples of A include the following.

Also, as a specific example of C _p These central skeleton A and coupler C _P to form a pigment as a charge generating material by an appropriate combination.

The charge generation layer can be formed by dispersing the above-described charge generation substance in an appropriate binder and applying the same to a support, or by forming a deposition film with a vacuum deposition device. Can be. The binder can be selected from a wide range of insulating resins, and can be selected from organic photoconductive polymers such as poly-N-vinyl carbazole, polyvinyl anthracene and polyvinyl pyrene. Preferably, polyvinyl butyral, polyarylate (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin, polyamide, polyvinyl pyridine, cellulose resin, urethane resin , An epoxy resin, an insulating resin such as casein, polyvinyl alcohol, and polyvinylpyrrolidone. 80% by weight of resin contained in charge generation layer
Or less, preferably 40% by weight or less. Organic solvents used for coating include methanol, ethanol,
Alcohols such as isopropanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, N,
Amides such as N-dimethylformamide and N, N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride , Dichloroethylene, carbon tetrachloride, aliphatic halogenated hydrocarbons such as trichloroethylene or benzene, toluene, xylene, monochlorobenzene,
Aromatic substances such as dichlorobenzene can be used.

The coating can be performed by a coating method such as a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a Meyer bar coating method, a blade coating method, a roller coating method, and a curtain coating method.

The charge generation layer contains as much of the organic photoconductor as possible to obtain sufficient absorbance, and injects carriers into the charge transport layer within the life of the generated charge carriers, a thin film layer, for example, 5 microns or less, preferably 0.01
It is preferable to form a thin film layer having a thickness of 1 micron to 1 micron. This means that most of the incident light amount is absorbed by the charge generation layer to generate many charge carriers, and the generated charge carriers are recombined or trapped.
It is necessary to inject into the charge transport layer without deactivation.

 Next, the polysilane layer 2 of the present invention will be described.

The method for synthesizing the polysilane compound used in the present invention is described in [The
The Journal of Organometallic Chemistry, 198pp,
C27 (1980) or The Journal of Polymer
Science Polymer Chemistry Edition (The Journal of Polymer Science, Polymer Chemistry)
Edition), Vol. 22, 159-170pp (1984).

 Examples of the polysilane used in the present invention are shown below.

(Each of x and y in the above structural formula represents a monomer polymerization unit. The copolymer represents a random copolymer.) In the present invention, the polysilane represented by the general formula (I) is particularly preferably used. Compounds are used.

Wherein R ₁ is an alkyl group having 1 or 2 carbon atoms, R ₂ is an alkyl group having 3 to 8 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group, and R ₃ is an alkyl group having 1 to 4 carbon atoms. And the group R ₄ represents an alkyl group having 1 to ₄ carbon atoms. A and A 'each represent an alkyl group having 4 to 12 carbon atoms;
It is a cycloalkyl group, an aryl group or an aralkyl group, both of which may be the same or different. Each of x and y represents a monomer polymerization unit. The polysilane compound represented by the general formula (I) used in the present invention can be synthesized as follows. That is,
Under a high-purity inert atmosphere free of oxygen and moisture, the dichlorosilane monomer is brought into contact with a condensation catalyst comprising an alkali metal to carry out halogen elimination and polycondensation to synthesize an intermediate polymer. It is synthesized by separating it from the monomer for the reaction, reacting the polymer with a predetermined halogenated organic reagent in the presence of a condensation catalyst comprising an alkali metal, and condensing an organic group to the terminal of the polymer.

In the above synthesis operation, the starting materials dichlorosilane, the intermediate polymer, the halogenated organic reagent, and the alkali metal condensation catalyst all have high reactivity with oxygen and moisture, so these oxygen and moisture are present. Under the atmosphere, the above-mentioned polysilane compound intended for the present invention cannot be obtained.

Therefore, the above-described operation for obtaining the polysilane compound represented by the general formula (I) needs to be performed in an atmosphere in which neither oxygen nor moisture exists. For this reason,
Care must be taken with respect to all of the reaction vessels and reagents used so that neither oxygen nor moisture is present in the reaction system. For example, for a reaction container, vacuum suction and argon gas replacement are performed in a blow box so that moisture and oxygen are not adsorbed in the system. In any case, the argon gas to be used is dehydrated by passing through a silica gel column in advance and then deoxidizing by passing the copper powder through a column heated to 100 ° C.

The dichlorosilane monomer, which is a starting material, is introduced into the reaction system after vacuum distillation using the above-described degassed argon gas immediately before introduction into the reaction system. The halogenated organic reagent for introducing a specific organic group and the solvent to be used are also introduced into the reaction system after being subjected to a deoxygenation treatment in the same manner as the dichlorosilane monomer. In the deoxidizing treatment of the solvent, the solvent is subjected to distillation under reduced pressure using the above-described deoxygenated argon gas, followed by further deoxidizing treatment with metallic sodium.

The above-mentioned condensation catalyst is used in the form of a wire or chip. The wire or chip is used in an oxygen-free paraffin-based solvent to prevent oxidation.

The starting material dichlorosilane monomer used in producing the polysilane compound represented by the general formula (I) is a silane compound represented by the general formula: R ₁ R ₂ SiCl ₂ or a silane compound represented by the general formula: R ₃ R ₄ A silane compound represented by SiCl ₂ is selectively used.

As the above-mentioned condensation catalyst, an alkali metal which causes a condensation reaction by elimination of halogen is desirably used, and specific examples of the alkali metal include lithium, sodium and potassium, and among them, lithium and sodium are preferable.

The above-mentioned halogenated organic reagent is for introducing a substituent represented by A and A ', and comprises an alkyl halide compound, a cycloalkyl halide compound, an aryl halide compound and an aralkyl halide compound. A suitable compound selected from the group, i.e. the general formula: A
-X and / or general formula: A'-X (where X is Cl or Br)
And an appropriate compound in the specific examples described later is selectively used.

The general formula used in synthesizing the above-mentioned intermediate polymer: R ₁ R ₂ SiCl ₂ or a dichlorosilane monomer represented by the general formula: R ₃ R ₄ SiCl ₂ is dissolved in a predetermined solvent to form a reaction system. As the solvent, a paraffinic non-polar hydrocarbon solvent is desirably used. Preferred examples of the solvent include n-hexane, n-octane, and n-hexane.
-Nonane, n-dodecane, cyclohexane and cyclooctane.

Since the resulting intermediate polymer is insoluble in these solvents, it is convenient to separate the intermediate polymer from unreacted dichlorosilane monomer. The separated intermediate polymer is then reacted with the above-mentioned halogenated organic reagent. At this time, both are dissolved in the same solvent and used for the reaction. As the solvent in this case, an aromatic solvent such as benzene, toluene and xylene is preferably used.

In order to obtain a desired intermediate by condensing the above-mentioned dichlorosilane monomer using the above-mentioned alkali metal catalyst, the polymerization degree of the obtained intermediate polymer can be appropriately controlled by adjusting the reaction temperature and the reaction time. However, the reaction temperature at that time is desirably set between 60 and 130 ° C.

One preferred embodiment of the method for producing the above-mentioned polysilane compound represented by the general formula (I) described above will be described below.

That is, the method for producing a polysilane compound represented by the general formula (I) according to the present invention comprises: (i) a step of producing an intermediate polymer; and (ii) adding substituents A and A ′ to the terminal of the intermediate polymer. And a step of introducing.

The step (i) is performed as follows. That is, the inside of the reaction system of the reaction vessel was completely removed of oxygen and moisture, maintained at a predetermined internal pressure controlled by argon, charged with an oxygen-free paraffin-based solvent and an oxygen-free condensation catalyst. The chlorosilane monomer is charged, and the whole is heated to a predetermined temperature while stirring to condense the monomer. At this time, the degree of condensation of the dichlorosilane monomer is
The reaction temperature and reaction time are adjusted so that an intermediate polymer having a desired degree of polymerization is produced.

In this reaction, as shown in the following reaction formula (i), the chloro group of the dichlorosilane monomer and the catalyst cause a desalination reaction, and the Si groups repeatedly condense to form an intermediate polymer. I do.

As a specific reaction procedure, a condensation catalyst (alkali metal) is charged in a paraffinic solvent, and a dichlorosilane monomer is added dropwise while stirring under heating. The degree of polymerization is confirmed by sampling the reaction solution.

Simple confirmation of polymerization can be determined by volatilizing the sampling liquid to form a film. As the condensation proceeds and the polymer is formed, it becomes a white solid and precipitates from the reaction system. Here, the mixture is cooled, and the solvent containing the monomer is separated from the reaction system by decantation to obtain an intermediate polymer.

Next, the step (b) is performed. That is, the chloro group of the terminal group of the obtained intermediate polymer is subjected to desalting condensation using a halogenated organic agent and a condensation catalyst (alkali metal) to replace the polymer terminal group with a predetermined organic group. The reaction at this time is represented by the following reaction formula.

Here, specifically, an aromatic solvent is added to and dissolved in the intermediate polymer obtained by condensation of the dichlorosilane monomer. Next, a condensation catalyst (alkali metal) is added, and a halogenated organic agent is added dropwise at room temperature. At this time, a halogenated organic agent is added in an amount of 0.01 to 0.1 times the amount of the starting monomer in order to compete with the condensation reaction between the polymer end groups. The mixture is gradually heated and stirred at 80 to 100 ° C. for 1 hour to carry out a desired reaction.

After completion of the reaction, the mixture is cooled, and methanol is added to remove the alkali metal of the catalyst. Next, the polysilane is extracted with toluene and purified with a silica gel column. Thus, a desired polysilane compound is obtained.

Examples of the polysilane represented by the general formula (I) used in the present invention are shown below.

(Each of x and y in the above structural formula represents a monomer polymerized unit. The copolymer represents a random polymer.) The layer 2 containing the above-mentioned polysilane compound forms the above-mentioned charge generating layer 3. It can be formed by the same method as in the case of. That is, the layer 2 containing the polysilane compound is prepared by dissolving the above-mentioned polysilane compound in a solvent preferably in an amount of 5 to 30% by weight, more preferably 10 to 20% by weight, based on the solvent to prepare a coating liquid. This is applied to form a liquid coat, and the liquid coat is dried and solidified. Examples of the solvent include aromatic solvents such as benzene, toluene, and xylene; halogen solvents such as dichloromethane, dichloroethane, and chloroform; and other solvents such as tetrahydrofuran and dioxane. The application of the coating liquid and the drying and solidification of the liquid coat can be performed in the same manner as in the shape of the charge generation layer.

An undercoat layer 5 having a barrier function and an adhesive function may be provided between the conductive support 4 and the charge generation layer 3. The undercoat layer 5 is made of casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, (nylon 6, nylon 66, nylon 610, copolymer nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin, aluminum oxide, etc. Can be formed by

The thickness of the undercoat layer is 0.1 to 5 microns, preferably 0.5 to
3 microns is suitable.

In the case of using a photoconductor in which a conductive layer, a charge generation layer, a polysilane layer, and a charge transport layer are stacked in this order, the charge transport compound has a hole transporting property, and therefore, it is necessary to negatively charge the surface of the charge transport layer, When exposed after charging, in the exposed area, holes generated in the charge generation layer are injected into the charge transport layer, and then reach the surface to neutralize negative charges, attenuate the surface potential, and cause static electricity between the unexposed area. Contrast occurs. At the time of development, it is necessary to use a positively charged toner, contrary to the case where an electron transport material is used.

In another embodiment of the present invention, the above-mentioned disazo pigment or U.S. Pat.Nos. 3,554,745, 3,567,438, 3,
Pigments having photoconductivity such as pyrylium dyes, thiapyrylium dyes, selenapyrylium dyes, benzopyrylium dyes, benzothiapyrylium dyes, naphthopyrylium dyes, naphthiapyrylium dyes disclosed in 586,500 and the like sensitize the dyes. It can also be used as an agent.

In another specific example, a eutectic complex of a pyrylium dye disclosed in US Pat. No. 3,684,502 or the like and an electric insulating polymer having an alkylidene diarylene moiety can be used as a sensitizer. This eutectic complex is, for example, 4-
[4-bis- (2-chloroethyl) aminophenyl]-
2,6-diphenylthiapyrylium perchlorate and poly (4,4'-isopropylidene diphenylene carbonate) are converted to halogenated hydrocarbon solvents (for example, dichloromethane, chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,1-dichloroethane). 2-dichloroethane, 1,1,2-trichloroethane,
After dissolving in chlorobenzene, bromobenzene, 1,2-dichlorobenzene, and adding a non-polar solvent (for example, hexane, octane, decane, 2,2,4-trimethylbenzene, ligroin) to the particles, The electrophotographic photoreceptor in this specific example includes a styrene-butadiene copolymer, a silicone resin,
Containing vinyl resin, vinylidene chloride-acrylonitrile copolymer, styrene-acrylonitrile copolymer, vinyl acetate-vinyl chloride copolymer, polyvinyl butyral, polymethyl methacrylate, poly-N-butyl methacrylate, polyesters, cellulose esters, etc. as a binder. Can be.

 Finally, the surface layer 1 of the present invention will be described.

Examples of the organic charge transporting substance contained in the surface layer of the present invention include pyrene, N-ethylcarbazole, N-methyl-N-phenylhydrazino-3-methylidene-9-ethylcarbazole, N, N-diphenylhydrazino- 3-methylidene-10-ethylphenothiazine, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone,
Hydrazones such as p-pyrrolidinobenzaldehyde-N, N-diphenylhydrazone and p-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 2,5-bis (p-diethylaminophenyl) -1,3, Four
-Oxadiazole, 1-phenyl-3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazolin, 1- [pyridyl (2)]-3- (p-
Diethylaminostyryl) -5- (p-diethylaminophenyl) pyrizoline, 1- [pyridyl (3)]-3-
(P-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, 1- [pyridyl (2)]
-3- (p-Diethylaminostyryl) -4-methyl-
5- (p-diethylaminophenyl) pyrazolin, 1-
Phenyl-3- (p-diethylaminostyryl) -4-
Pyrazolines such as methyl-5- (p-diethylaminophenyl) pyrazoline and spiropyrazoline, α-phenyl-4-N, N-diphenylaminostilbene, N-ethyl-3 (α-phenylstyryl) carbazole, 9-dibenzylamino Benzylidene-9H-fluorenone, 5-p
-Ditolylaminobenzylidene-5H-dibenzo [a, d]
Styryl compounds such as cycloheptene, 2- (p-diethylaminostyryl) -6-diethylaminobenzoxazole, 2- (p-diethylaminophenyl) -4
Oxazole compounds such as-(p-dimethylaminophenyl) -5- (2-chlorophenyl) oxazole,
Thiazole compounds such as 2- (p-diethylaminostyryl) -6-diethylaminobenzothiazole, triarylmethane compounds such as bis (4-diethylamino-2-methylphenyl) -phenylmethane, 1,1-bis (4- N, N-diethylamino-2-methylphenyl)
Examples include polyarylalkanes such as heptane and 1,1,2,2 tetrakis (4-N, N-dimethylamino-2-methylphenyl) ethane, and triarylamines such as triphenylamine.

These organic charge transport materials can be used alone or in combination of two or more.

Resin that can be used as a binder of the organic charge substance of the surface layer of the present invention, for example, acrylic resin, polyarylate, polyester, polycarbonate, polystyrene,
Acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral,
Examples thereof include insulating resins such as polyvinyl formal, polysulfone, polyacrylamide, polyamide, and chlorinated rubber, and organic photoconductive polymers such as poly-N-vinyl carbazole, polyvinyl anthracene, and polyvinyl pyrene.

Since the resin layer containing the organic charge transporting material has a limit to transport charge carriers, it cannot be made thicker than necessary. Generally, it is 30 μm or less, but a preferred range is 10 μm or less.

Further, the organic solvent used when forming the resin layer containing the organic charge transporting substance differs depending on the type of the binder used, and may be selected from those which do not dissolve the charge generating layer or the undercoat layer described below. preferable. Specific organic solvents include methanol, ethanol, alcohols such as isopropanol, acetone, methyl ethyl ketone, ketones such as cyclohexanone, N, N-dimethylformamide, amides such as N, N-dimethylacetamide, dimethyl sulfoxide and the like Sulfoxides, ethers such as tetrahydrofuran, dioxane and ethylene glycol monomethyl ether; esters such as methyl acetate and ethyl acetate; and aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene. Or benzene, toluene,
Aromatic substances such as xylene, monochlorobenzene, and dichlorobenzene can be used.

Coating can be performed using a coating method such as a dip coating method, a spray coating method, a spinner coating method, a beat coating method, a Meyer bar coating method, a blade coating method, a roller coating method, and a curtain coating method. Drying is preferably performed by touch drying at room temperature and then heating and drying. The heating and drying is generally preferably carried out at a temperature of 30 to 200 ° C. for a time in the range of 5 minutes to 2 hours, still or under blowing.

Further, the resin layer including the organic charge transporting layer of the present invention may contain various additives. For example,
Plasticizers such as diphenyl, m-terphenyl, dibutyl phthalate, silicone oil, grafted silicone polymer, surface lubricants such as various fluorocarbons, dicyanovinyl compounds, potential stabilizers such as carbazole derivatives, β-carotene, Ni complex, 1,4-diazabicyclo [2,
2,2] octane and other antioxidants.

In any of the above-described electrophotographic photoreceptors,
When the next constituent layer is formed on the previously formed constituent layer, it is important to select and use a solvent that does not dissolve the previously formed constituent layer.

The electrophotographic photoreceptor of the present invention described above can be applied not only to various electrophotographic copying machines but also to laser beam printers, CRT printers, LED printers, liquid crystal printers, laser plate making, and the like.

(Production example of polysilane compound used in the present invention)

Hereinafter, a specific production method of the polysilane compound used in the present invention will be described with reference to production examples.

Production Example 1 A three-necked flask was prepared in a blow box in which vacuum suction and argon substitution were performed, and a reflux condenser, a thermometer, and a dropping funnel were attached to the flask, and argon gas was passed through a bypass pipe of the dropping funnel.

100 g of dehydrated dodecane and 0.3 mol of metal wire were charged into the three-necked flask, and heated to 100 ° C. with stirring. Next, 0.1 mol of dichloromethylphenylsilane monomer (manufactured by Chisso Corporation) was added to dehydrated dodecane 3
The solution was dissolved in 0 g, and the prepared solution was slowly dropped into the reaction system.

After the dropwise addition, a white solid was precipitated by condensation polymerization at 100 ° C. for 1 hour. After cooling, decant the dodecane and add 100 grams of dehydrated toluene to dissolve the white solid.
01 mole was added. Next, a solution prepared by dissolving 0.01 mol of n-hexyl chloride (manufactured by Tokyo Kasei) in 10 ml of toluene was slowly added dropwise to the reaction system while stirring, and then added.
Heated at 100 ° C. for 1 hour. The mixture was cooled with heat, and 50 ml of methanol was slowly added dropwise to treat excess metal sodium. This produced a suspension layer and a toluene layer.

Next, the toluene layer was separated, concentrated under reduced pressure, and developed and purified by silica gel column and chromatography to obtain polysilane compound No. 1 (b-1). The yield was 65%.

The weight average molecular weight of this polysilane compound was 75,000 as determined by developing with THF by GPC (polystyrene as a standard).

Production Example 2 A three-necked flask was prepared in a blow box in which vacuum suction and argon substitution were performed, and a reflux condenser, a thermometer, and a dropping funnel were attached to the flask, and argon gas was passed through a bypass pipe of the dropping funnel.

100 g of dehydrated n-hexane and 0.3 mol of 1 mm square metal sodium were charged into the three-necked flask and heated to 80 ° C. with stirring. Next, 0.1 mol of dichloromethylcyclohexylsilane monomer (manufactured by Chisso Corporation) was dehydrated with n-
A solution prepared by dissolving in hexane was slowly dropped into the reaction system. After the dropping, condensation polymerization was carried out at 80 ° C. for 3 hours to precipitate a white solid. Thereafter, the mixture was cooled, n-hexane was decanted, and 100 g of dehydrated toluene was further added to dissolve the white solid, and 0.01 mol of metallic sodium was added. Next, a solution prepared by dissolving 10 ml of toluene in 0.01 mol of n-hexyl chloride (manufactured by Tokyo Chemical Industry) was slowly added dropwise to the reaction system with stirring, and the mixture was heated at 80 ° C. for 1 hour. Thereafter, the mixture was cooled, and 50 ml of methanol was slowly added dropwise to treat excess metal sodium. This produced a suspension layer and a toluene layer.

Next, the toluene layer was separated, concentrated under reduced pressure, and developed and purified by silica gel column and chromatography to obtain polysilane compound No. 2 (b-10). The yield was 58% and the weight average molecular weight was 120,000.

Production Examples 3 to 5 Polysilane No. 3 was produced in the same manner as Production Example 2, and Polysilane Nos. 4 and 5 were produced in the same manner as Production Example 1.

Polysilane Nos. 1 to 5 obtained by Production Examples 1 to 5
Are summarized in Table 1 below.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 For the photoreceptor, first, an aluminum substrate was prepared, and then 10 parts by weight (hereinafter referred to as “parts”) of a disazo pigment represented by the following structural formula 1 and 5 parts of polyvinyl butyral were added to 90 parts of MEK as a coating liquid for a charge generation layer. The resultant was dispersed in a ball mill, coated with a wire bar, and dried to form a charge generation layer having a thickness of 0.3 μm.

On the charge generation layer, polysilane No. 1 was dissolved in toluene, coated with a wire bar, and dried to form a 10 μm-thick polysilane layer.

Next, 10 parts of the compound of the following formula 2 and 10 parts of a polycarbonate resin (average molecular weight: 20,000) are dissolved in 70 parts of monochlorobenzene as a charge transporting substance, and this solution is applied on the previous charge generating layer with a Meyer bar. A charge transport layer having a dry film thickness of 5 μm was provided to prepare a three-layer electrophotographic photoreceptor.

The electrophotographic photoreceptor thus prepared was corona-charged at −5 kV in a static manner using an electrostatic copying paper tester Model-SP-428 manufactured by Kawaguchi Electric Co., Ltd., and was held for 1 second in a dark place. Exposure was performed at an illuminance of 20 lux, and charging characteristics were examined.

The charged properties, surface electrical (V ₀₎ and the exposure required to attenuate one second potential when was dark decay to (V ₁₎ to 1/2 (E1 /
2) was measured.

Further, in order to measure the fluctuation of the light portion potential and the dark portion potential when repeatedly used, the photoconductor produced in this example was attached to a cylinder for a photoconductive drum of a PPC copier NP-3525 manufactured by Canon Inc. Then, 1000 copies were made with the same machine, and the image after 1000 copies was examined.

 The results are shown in Table 2.

Comparative Example 1 In this comparative example, a photoreceptor provided with a polysilane layer up to and including the polysilane layer was produced and evaluated in the same manner as in Example 1. The results are shown in Table 2.

Example 2 A photoconductor was prepared and evaluated in the same manner as in Example 1, except that the compound of the following structural formula 3 was used as the charge generating substance.

 The results are shown in Table 3.

Example 3 A photoreceptor was prepared and evaluated in the same manner as in Example 2, except that Exemplified No. 2 was used as a polysilane compound and polystyrene was used as a binder and a compound represented by the following structural formula 4 as a charge transport material.

 The results are shown in Table 3.

Example 4 A photoconductor was prepared and evaluated in the same manner as in Example 3, except that Exemplified No. 3 was used as the polysilane compound.

 The results are shown in Table 3.

Comparative Examples 2 to 4 Photoconductors up to the polysilane layer were prepared and evaluated in the same manner as in Examples 2 to 4 except that the charge transport layer was not provided.

 The results are shown in Table 3.

Example 5 A solution prepared by dissolving 5 g of methoxymethylated iron resin (average molecular weight: 32,000) and 10 g of alcohol-soluble copolymerized nylon resin (average molecular weight: 29000) in 95 g of methanol was applied on an aluminum substrate by a Meyer bar, and the film thickness after drying was applied. Provided an undercoat layer of 1 μm.

Next, 10 g of a charge generating substance represented by the following structural formula 5, 5 g of butyral resin (butyralization degree: 63 mol%) and 200 g of dioxane were dispersed by a ball mill for 48 hours.
This dispersion was applied on the undercoat layer manufactured previously by a blade coating method to form a charge generation layer having a thickness of 0.15 μm after drying.

Next, the polysilane compound of Example No. 4 was dissolved in xylene, applied by a wire bar, and dried to a thickness of 8 μm.
Was formed.

Next, 10 g of the charge transport material of the following structural formula 6 Polymethyl methacrylate resin (average molecular weight 50,000) 1
0 g was dissolved in 70 g of monochlorobenzene, and applied on the previously formed charge generation layer by a blade coating method,
A charge transport layer having a thickness of 10 microns after drying was formed.

The photoreceptor thus produced was subjected to a -5 kV corona discharge. The surface potential at this time was measured (initial electron V ₀ ). Further, the surface potential of this photoconductor after leaving it in a dark place for 1 second was measured. Sensitivity, exposure required to attenuate the potential V ₁ of the after dark decay to 1/2 was evaluated by measuring (E1 / 2 microjoules / cm ^2). At this time, a gallium / aluminum / arsenic ternary semiconductor laser (output: 5 mW; oscillation wavelength: 780 nm) was used as a light source. The results were as follows.

V ₀ : −725 V V ₁ : −710 V E1 / 2: 0.43 microjoules / cm ² Next, a laser beam printer that is a reversal development type electrophotographic printer equipped with a semiconductor laser as described above (Canon LBP-CX) The above photoreceptor was replaced with a photoreceptor of LBP-CX and set, and an actual image forming test was used. The conditions are as follows. Surface potential after temporary charging:
-700V, surface potential after image exposure; -150V (exposure amount 2.0μJ / c
m ² ) Transfer potential +700 V, developer polarity; negative polarity, process speed; 50 mm / sec, development conditions (development bias): -450
V, Image exposure scan method; Image scan, exposure before primary charging; Red exposure of 50 lux sec, red line exposure, image formation was performed by line scanning with laser beam according to character signal and image signal, but both character and image were printed well was gotten. Furthermore, when 1000 images were continuously printed, stable and good prints were obtained from the initial to 1000 sheets.

Example 6 10 g of zinc phthalocyanine was added to a solution prepared by dissolving 5 g of a phenoxy resin in 485 g of dioxane, and dispersed in a ball mill for 2 hours. This dispersion was applied on an aluminum sheet with a Meyer bar and dried at 80 ° C. for 2 hours to form a 0.5 μm charge generation layer.

Next, a solution in which the polysilane compound of Example No. 5 was dissolved in dichloromethane was applied by a wire bar, and a polysilane layer having a thickness of 10 μm after drying was formed.

Next, 10 g of a compound represented by the following structural formula 7, A solution prepared by dissolving 10 g of bisphenol Z-type polycarbonate resin (weight average molecular weight: 50,000) in 70 g of monochlorobenzene is applied to the previously formed polysilane layer with a Meyer bar, and dried at 110 ° C. for 1 hour to form a 5 μm charge transport layer. Formed. The photoreceptor manufactured in this manner was used in Example 5
It was measured in the same manner as described above. The results are shown below.

V ₀ : −683 V V ₁ : −674 V E1 / 2: 0.35 μJ / cm ^{2 Further} , stable and good prints were obtained from the initial stage to 1000 sheets.

Example 7 4- (4-Dimethylaminophenyl) -2,6-diphenylthiapyrylium and 3 g of perchlorate were exemplified. 100 g of a solution of the No. 1 polysilane compound in toluene (50 parts by weight) and dioxane (50 parts by weight). And dispersed in a ball mill for 6 hours. This dispersion was applied to an aluminum sheet with a Meyer bar and dried at 100 ° C. for 2 hours to form a 10 μm photosensitive layer.

Next, 10 g of a charge transport material of the following structural formula 8, A solution prepared by dissolving 10 g of a polyester resin (weight average molecular weight 49000) in 70 g of monochlorobenzene was applied by a wire bar, and a charge transport layer having a thickness of 5 μm after drying was formed. The photoreceptor thus produced was evaluated in the same manner as in Example 1, and the results are shown in Table 4.

Example 8 The compound of the following structural formula 9 was used as the charge generating material, and the compound of Example 5 was used as the charge transporting material in Example 1.
A photoreceptor was prepared in the same manner as in Example 1, and evaluated in the same manner as in Example 1. The results are shown in Table 4.

Example 9 An aluminum sheet on which aluminum chlorophthalocyanine was vapor-deposited was used as a charge generation layer in the same manner as in Example 1 except that a polysilane layer was used.
A charge transport layer was provided, a photoreceptor was prepared, and evaluated in the same manner as in Example 1. The results are shown in Table 4.

Example 10 A photoconductor was prepared and evaluated in the same manner as in Example 9, except that the polysilane of Example No. 2 was used for the polysilane layer, and the compound of the following structural formula 10 was used for the charge transport material. The results are shown in Table 4.

[Summary of Effects of the Invention] As described above, as can be seen from the examples and comparative examples, when the surface layer is a polysilane compound, the polysilane compound is brittle,
It is scraped by the blade and is not durable. However, by providing a resin layer containing an organic charge transporting material on the surface layer, an electrophotographic photoreceptor having improved chargeability, high sensitivity and excellent durability can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a photoconductor in which a charge generation layer in which a charge generation substance is dispersed in a binder, a polysilane layer, and a surface layer containing an organic charge transport substance are laminated. FIG. 2 is a schematic cross-sectional view of a photoreceptor further having an undercoat layer in the layer constitution of the photoreceptor shown in FIG. DESCRIPTION OF SYMBOLS 1 ... Resin layer containing an organic charge transport material, 2 ... Polysilane layer, 3 ... Charge generation layer, 4 ... Substrate, 5 ... Undercoat layer.

Claims (4)

(57) [Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer comprises a charge generation layer and a polysilane compound represented by the following general formula laminated on the charge generation layer. An electrophotographic photoconductor, comprising: a photosensitive layer; and a surface layer formed of a resin layer containing an organic charge transport material on the photosensitive layer. Wherein R ₁ is an alkyl group having 1 or 2 carbon atoms, R ₂ is an alkyl group having 3 to 8 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group, and R ₃ is an alkyl group having 1 to 4 carbon atoms. And the group R ₄ represents an alkyl group having 1 to ₄ carbon atoms. A and A 'each represent an alkyl group having 4 to 12 carbon atoms;
It is a cycloalkyl group, an aryl group or an aralkyl group, both of which may be the same or different. Each of x and y represents a monomer polymerization unit. ] 2. The method according to claim 1, wherein the photosensitive layer containing the polysilane compound is formed by applying a solution of the polysilane compound represented by the general formula and containing no binder. The photosensitive member for electrophotography according to the above. 3. The electrophotographic photoreceptor according to claim 1, wherein said charge generation layer contains an organic charge generation substance. 4. The organic charge transport material is selected from hydrazones, pyrazolines, styryl compounds, oxazole compounds, triarylmethane compounds, polyarylalkanes, and triarylamine compounds. The electrophotographic photosensitive member according to claim 1, wherein: