JP2003076039A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor, the photosensitive layer of which is excellent in mechanical strength and surface smoothness and contains a polyester resin having high and stable solubility as a binder resin. SOLUTION: The photosensitive layer of the electrophotographic photoreceptor contains a binder resin having a polyester structure expressed by general formula (1). In formula (1), A represents a bivalent organic group, X is one kind selected from the group of the following structural formulae (A), (B) and (C), and A is not any of the structural formulae (A), (B) and (C), however, when X is the structural formula (A), m and n satisfy 0.01<=m/(m+n)<0.9 and when X is the structural formula (B) or (C), m and n satisfy 0.01<=m/(m+n)<=1.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyester resin and a polyester polycarbonate resin having a novel structure. More particularly, it relates to a polyester resin or a polyester polycarbonate resin having excellent mechanical strength and surface slipperiness when used as a binder for a photosensitive layer of an electrophotographic photoreceptor.

[0002]

2. Description of the Related Art Electrophotographic technology has been widely used and applied not only in the field of copying machines but also in the field of various printers in recent years because of its ability to obtain images of instant quality and high quality. The electrophotographic photoconductor is repeatedly used in the electrophotographic process, that is, the cycle of charging, exposure, development, transfer, cleaning, charge removal, etc., and therefore, it is subjected to various stresses and deteriorates. As such deterioration, for example, strongly oxidizing ozone or NOx generated from a corona charger, which is commonly used as a charger, chemically damages the photosensitive layer, or carriers (current) generated by image exposure. Flow through the photosensitive layer, and the composition of the photosensitive layer is decomposed by static elimination light or light from the outside to cause chemical or electrical deterioration.
Further, as another deterioration, there are mechanical deterioration such as abrasion and scratches on the surface of the photosensitive layer due to rubbing of cleaning blade, magnetic brush and the like, contact with developer and paper, and peeling of the film. In particular, such damage on the surface of the photosensitive layer is likely to appear on the copy image and directly deteriorates the image quality, which is a major factor limiting the life of the photosensitive member. That is, in order to develop a photoreceptor having a long life, it is an essential condition to enhance electrical and chemical durability as well as mechanical strength.

In the case of a laminated type photoreceptor, it is the charge transfer layer that generally receives such a load. The charge transfer layer usually consists of a binder resin and a charge transfer material, and it is the binder resin that substantially determines the strength, but since the doping amount of the charge transfer material is considerably large, it has not been possible to provide sufficient mechanical strength. Not in. So far, as the binder resin of the charge transfer layer of the electrophotographic photoreceptor, vinyl polymers such as polymethylmethacrylate, polystyrene, polyvinyl chloride,
And copolymers thereof, polycarbonate, polyester,
Thermoplastic resins such as polysulfone, phenoxy, epoxy and silicone resins and various thermosetting resins have been used. Among many binder resins, polycarbonate resin has relatively excellent performance, and various polycarbonate resins have been developed and put into practical use. For example, JP-A-50-98332 discloses bisphenol P type polycarbonate and JP-A-59-7.
No. 1057 discloses a bisphenol Z type polycarbonate, JP-A-59-184251 discloses a copolymer type polycarbonate of bisphenol P and bisphenol A, and JP-A-5-21478 discloses bis (4-hydroxyphenyl). ) Polycarbonate copolymers containing a ketone type structure are each disclosed as a binder resin. However, conventional organic photoreceptors have drawbacks such as surface abrasion and scratches due to practical load such as development with toner, friction with paper, and friction with cleaning member (blade). Therefore, the printing performance is currently limited to practical use.

On the other hand, Japanese Unexamined Patent Publication No. 56-135844 discloses a technique of an electrophotographic photoreceptor using a polyarylate (aromatic polyester) resin commercially available under the trade name "U-polymer" as a binder. Among them, it is shown that the sensitivity is particularly excellent as compared with polycarbonate. Further, JP-A-3-6567 discloses an electrophotographic photosensitive member characterized by containing a polyarylate (aromatic polyester) copolymer having a structure in which tetramethylbisphenol F and bisphenol A are used as a bisphenol component. ing. However, these aromatic polyesters have drawbacks such as poor solubility in the coating solvent of the photosensitive layer and stability of the solution, and the use of these aromatic polyesters as a binder of the photosensitive layer causes deterioration of electrical characteristics.

In order to increase mechanical strength, for example, an overcoat layer is provided (JP-A-61-72256), and a binder polymer having high abrasion resistance is used (JP-A-63-148263). Kaihei 3-221
No. 962) has been proposed, but all of them have problems such as insufficient effects or adverse effects on characteristics such as electric characteristics.

[0006]

When the presently used polycarbonate resin is used as a binder resin for an electrophotographic photosensitive member, the abrasion resistance, scratch resistance, surface slipperiness and the like are still insufficient in many cases. . Further, although the commercially available polyarylate resin "U-polymer" shows some improvement in abrasion resistance and sensitivity, the stability of the coating solution is poor,
Coating production was impossible, and slipperiness was poor. Further, in the case of using a polyarylate (aromatic polyester) copolymer having a structure using tetramethylbisphenol F and bisphenol A as the bisphenol component disclosed in Japanese Patent Laid-Open No. 3-6567, it is conventional in terms of abrasion resistance. Although improved compared to the polycarbonate of
In terms of slipperiness, superiority to polycarbonate is not recognized.

Therefore, at present, there is a demand for a binder resin having excellent wear resistance and slipperiness.

[0008]

The inventors of the present invention have studied in detail the binder resin used in the photosensitive layer. As a result, the polyester resin produced by polymerizing repeating units having a specific structure in a specific ratio is extremely effective. It has been found that it has excellent slipperiness, high solubility in a non-halogen-based solvent / improvement in storage stability of a coating solution, and excellent abrasion resistance, and the present invention has been completed.

That is, the gist of the present invention is that in an electrophotographic photoreceptor having at least a photosensitive layer on a conductive substrate, the binder resin of the photosensitive layer has a polyester structure represented by the following general formula (1). An object is to provide a characteristic electrophotographic photosensitive member.

[0010]

[Chemical 4]

(In the general formula (1), A represents a divalent organic group, and X is one selected from the group represented by the following structural formulas (A), (B) and (C). The following structural formula (A),
It is neither (B) nor (C).

[0012]

[Chemical 5]

However, when X is the structural formula (A), 0.01 ≦
m / (m + n) <0.9, and when X is the structural formula (B) or the structural formula (C), 0.01 ≦ m / (m + n) ≦ 1. )

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION As the binder resin of the present invention, a resin having a polyester structure represented by the above general formula (1) is used, and in the general formula (1), A represents a divalent organic group. However, the following structures are specifically mentioned.

[0015]

[Chemical 6]

[0016]

[Chemical 7]

Y in the general formula (2) is specifically a single bond,
—S—, —O—, a sulfonyl group, a cycloalkyl group, or —CR ³⁹ R ⁴⁰ —. R ^{1 to} R ⁴⁰ represent hydrogen, an alkyl group, an aryl group, an allyl group, a halogen atom, and an alkoxyl group. Specific examples of R ^{1 to} R ⁴⁰ include hydrogen atom, chlorine atom, fluorine atom, bromine atom, phenyl group, naphthyl group, methoxy group, ethoxy group, methyl group, ethyl group, n-propyl group, isopropyl group, n. -Butyl group,
Isobutyl group, tert-butyl group, sec-butyl group, n-pentyl group, cyclopentyl group, iso-pentyl group, sec-pentyl group, neo-pentyl group, 2
-Methylbutyl group, 1,1-dimethylpropyl group, 1-
Examples thereof include ethylpropyl group, n-hexyl group, cyclohexyl group, n-octyl group and n-nonyl group. Of these, a hydrogen atom and a methyl group are preferable. General formula (7),
Although a and b in (8) represent an integer of 1 or more, preferably 1
~ 6.

The copolymerization component ratios n and m of the above-mentioned general formula (1)
Is 0.01 ≦ m / (m + n) <0.9 when X is the above structural formula (A) (p, p′-BPF), but preferably 0.1 ≦ m / (m + n) ≦ 0. 7 and more preferably 0.
1 ≦ m / (m + n) ≦ 0.4. When m / (m + n) is less than 0.01, the effect of improving electrical properties by p, p'-BPF is small, and when m / (m + n) is 0.9 or more, it becomes insoluble in the coating solvent as shown in Comparative Example 3, and the invention Not suitable for use. X in the above structural formula (B) is the above structural formula (C)
(O, p'-BPF) or general formula (4) (o, o'-B
In the case of (PF), n and m are 0.01 ≦ m / (m + n)
≦ 1, preferably 0.1 ≦ m / (m + n) ≦ 0.
9 More preferably, 0.1 ≦ m / (m + n) ≦ 0.7. When m / (m + n) is less than 0.01, o, p '
-BPF or o, o'-BPF has a small effect of improving electric properties, and when it is 0.9 or more, the polymerization reaction rate is lowered and mechanical properties are lowered, which is not preferable.

The viscosity average molecular weight of the polyester resin of the present invention is preferably 10,000 or more and 100,000 or less, more preferably 15,000 or more and 50,000 or less. When the viscosity average molecular weight is less than 10,000, mechanical strength and abrasion resistance are deteriorated, which is not preferable. Further, when the viscosity average molecular weight exceeds 100,000, the viscosity of the coating solution is high and coating becomes difficult. The content of the structural unit represented by the general formula (1) in the binder resin of the photosensitive layer of the present invention is preferably 10% by weight or more and 100% by weight or less, more preferably 50% by weight or more and 100% by weight or less. .

The polyester resin of the present invention is a constituent component of a structure other than the structural formulas (A), (B) and (C).
Specific examples of the dihydric alcohol or dihydric phenol include hydroquinone, resorcinol, 1,
3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-
Dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,1-bis- (4-hydroxyphenyl) ethane (BPE), 1,1-bis- (4- Hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) propane (BPA), bis- (4-
Hydroxy-3,5-dimethylphenyl) methane (Tm
BPF), 2,2-bis- (4-hydroxyphenyl)
Butane, 2,2-bis- (4-hydroxyphenyl) pentane, 2,2-bis- (4-hydroxyphenyl)-
3-methylbutane, 2,2-bis- (4-hydroxyphenyl) hexane, 2,2-bis- (4-hydroxyphenyl) -4-methylpentane, 1,1-bis- (4-
Hydroxyphenyl) cyclopentane, 1,1-bis-
(4-hydroxyphenyl) cyclohexane (BP
Z), bis- (3-phenyl-4-hydroxyphenyl) methane, 1,1-bis- (3-phenyl-4-hydroxyphenyl) ethane, 1,1-bis- (3-phenyl-4-hydroxyphenyl) ) Propane, 2,2-bis- (3-phenyl-4-hydroxyphenyl) propane (BPQ), bis- (4-hydroxy-3-methylphenyl) methane (Cof), 1,1-bis- (4- Hydroxy-3-methylphenyl) ethane (Ce), 2,2-
Bis- (4-hydroxy-3-methylphenyl) propane (BPC), 2,2-bis- (4-hydroxy-3-)
Ethylphenyl) propane, 2,2-bis- (4-hydroxy-3-isopropylphenyl) propane, 2,2
-Bis- (4-hydroxy-3-sec-butylphenyl) propane, 1,1-bis- (4-hydroxy-3,
5-dimethylphenyl) ethane (Xe), 2,2-bis- (4-hydroxy-3,5-dimethylphenyl) propane (Tma), bis- (4-hydroxy-3,6-dimethylphenyl) methane (Xf) ), 1,1-bis- (4
-Hydroxy-3,6-dimethylphenyl) ethane,
1,1-bis- (4-hydroxyphenyl) -1-phenylethane (BPP), 1,1-bis- (4-hydroxyphenyl) -1-phenylpropane, bis- (4-hydroxyphenyl) diphenylmethane, bis -(4-hydroxyphenyl) dibenzylmethane, 4,4'-dihydroxydiphenyl ether (BPO), 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, phenolphthalein, 4,
4 ′-[1,4-phenylenebis (1-methylvinylidene)] bisphenol, 4,4 ′-[1,4-phenylenebis (1-methylvinylidene)] bis [2-methylphenol] and the like can be mentioned. Among these, preferred examples are 1,1-bis- (4-hydroxyphenyl) ethane (BPE), 2,2-bis- (4-hydroxyphenyl) propane (BPA) and bis- (4-hydroxy-).
3,5-dimethylphenyl) methane (TmBPF),
2,2-bis- (3-phenyl-4-hydroxyphenyl) propane (BPQ), bis- (4-hydroxy-3)
-Methylphenyl) methane (Cof), 1,1-bis-
(4-hydroxyphenyl) cyclohexane (BP
Z), 1,1-bis- (4-hydroxy-3-methylphenyl) ethane (Ce), 2,2-bis- (4-hydroxy-3-methylphenyl) propane (BPC), bis- (4- Hydroxyphenyl) methane (Tmf), 1,
1-bis- (4-hydroxy-3,5-dimethylphenyl) ethane (Xe), 2,2-bis- (4-hydroxy-3,5-dimethylphenyl) propane (Tma), bis- (4-hydroxy) Examples include -3,6-dimethylphenyl) methane (Xf) and 1,1-bis- (4-hydroxyphenyl) -1-phenylethane (BPP). Particularly preferred is 2,2-bis- (4-hydroxyphenyl) propane (BPA), bis- (4-hydroxy-).
3,5-dimethylphenyl) methane (TmBPF),
1,1-bis- (4-hydroxyphenyl) cyclohexane (BPZ), 2,2-bis- (4-hydroxy-3)
-Methylphenyl) propane (BPC). As the aliphatic dihydroxy compound, ethylene glycol, propylene glycol, 1,4-butanediol,
1,4-pentanediol, pentamethylenediol,
2,4-Pentanediol, 1,5-hexanediol, hexamethylene glycol, 1,5-heptanediol, heptamethylenediol, octamethylenediol, 1,9-nonanediol, 1,10-decamethyleneglycol, 1, 6-Cyclohexanediol and the like can be mentioned, but ethylene glycol, propylene glycol and 1,4-butanediol are preferable.

Further, the polyester resin of the present invention may be a copolymer with another resin. The copolymerization method may be block, graft or multi-block copolymer. Examples of other resin structures to be copolymerized here include various resins such as polycarbonate, polysulfone, polyether, polyketone, polyamide, polysiloxane, polyimide, polystyrene, and polyolefin. Among these, polycarbonate is the most preferable from the viewpoint of electrical properties and mechanical properties. From the viewpoint of mechanical properties, the amount of the copolymerization component other than polyester is usually 70 mol% or less, preferably 50 mol% or less, and most preferably 30 mol% or less in the total copolymer.

The polyester resin of the present invention can be mixed with other resins and used for an electrophotographic photoreceptor or the like. Other resins to be mixed here include vinyl polymers such as polymethylmethacrylate, polystyrene, and polyvinyl chloride and copolymers thereof, thermoplastic resins such as polycarbonate, polyester, polysulfone, phenoxy, epoxy, and silicone resin, and various resins. The thermosetting resin and the like are listed. Among these resins, polycarbonate resin is preferred. The amount of the other resin which may be used in combination with the polyester resin of the present invention is usually 50% by weight or less, preferably 30% by weight in the total binder resin.
Below, most preferably it is 10 weight% or less. When the polyester resin of the present invention is used as a surface slipperiness modifier, a flame retardancy-imparting agent or the like, 50% by weight or less, preferably 20% by weight or less, and most preferably 5% by weight or less of the total resin is used. It may be used as a mixture with polyester or other resin not containing a siloxane structure.

As a method for producing the polyester resin of the present invention, a known polymerization method can be used, including an interfacial polymerization method,
A melt polymerization method, a solution polymerization method and the like can be mentioned. For example, in the case of producing a polyester resin by an interfacial polymerization method, a solution obtained by dissolving one or more kinds of bifunctional phenol components or bisphenol components in an alkaline aqueous solution and a halogenated solution in which one or more kinds of aromatic dicarboxylic acid chloride components are dissolved. Mix with the hydrocarbon solution. At this time, a quaternary ammonium salt or a quaternary phosphonium salt can be present as a catalyst. Polymerization temperature is usually 0-40
In terms of productivity, it is preferable that the temperature is in the range of 0 ° C. and the polymerization time is in the range of 2 to 12 hours. After completion of the polymerization, the aqueous phase and the organic phase are separated, and the polymer dissolved in the organic phase is obtained by a known method.
The desired resin can be obtained by washing and collecting.

As the alkaline component used here,
Examples thereof include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. The amount of alkali used is 1. of the phenolic hydroxyl group contained in the reaction system.
The range of 0 to 3 times equivalent is preferable. Further, examples of the halogenated hydrocarbon used here include dichloromethane, chloroform, 1,2-dichloroethane, trichloroethane, tetrachloroethane, dichlorobenzene and the like.

Examples of the quaternary ammonium salt or quaternary phosphonium salt used as a catalyst include salts of tertiary alkylamines such as tributylamine and trioctylamine with hydrochloric acid, bromic acid and iodic acid, benzyltriethylammonium chloride and benzyltrimethyl. Ammonium chloride, benzyltributylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, trioctylmethylammonium chloride, tetrabutylphosphonium bromide, triethyloctadecylphosphonium bromide, N-laurylpyridinium chloride, laurylpicolinium chloride, etc. Can be mentioned.

Specific examples of the bifunctional phenol component or bisphenol component include the above-mentioned aromatic diols and the like, but it is also possible to use one kind or a mixture of two or more kinds thereof. Further, at the time of polymerization, phenol, o-, m-, p-cresol, o-, m-, p-ethylphenol, o-, m-, as a molecular weight regulator,
Alkylphenols such as p-propylphenol, o-, m-, p-tert-butylphenol, pentylphenol, hexylphenol, octylphenol, nonylphenol, o-, m-, p-phenylphenol, 2,4,6-trimethylphenol , 2, 3, 6-
Trimethylphenol, 2,6-dimethyl-4-tert-
Monofunctional acid halides such as monofunctional phenols such as butylphenol, acetic acid chloride, butyric acid chloride, octyl acid chloride, benzoyl chloride, benzenesulfonyl chloride, benzenesulfinyl chloride, sulfinyl chloride, benzenephosphonyl chloride and their substitution products. May exist.

The method for purifying the resin after polymerization is to use a solution of the resin in an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide,
After washing with aqueous acid such as hydrochloric acid, nitric acid, phosphoric acid, water, etc.,
The liquid may be separated by stationary separation, centrifugation, or the like. Further, by purifying by a method of precipitating the generated resin solution in a solvent in which the resin is insoluble, a method of dispersing the resin solution in warm water and distilling off the solvent, or a method of circulating the resin solution through an adsorption column or the like. Is also good.

The resin after purification is precipitated in water, alcohol, or other organic solvent in which the resin is insoluble, or the solution of the resin is distilled off in warm water or a dispersion medium in which the resin is insoluble, or by heating, depressurizing, etc. May be taken out by distilling off the solvent by, or when taken out as a slurry, a centrifugal separator,
It is also possible to remove the solid with a filter. The obtained resin is usually dried at a temperature not higher than the decomposition temperature of the resin, but preferably at a temperature not lower than 20 ° C. and not higher than the melting temperature of the resin under reduced pressure. The drying time is not less than the time until the purity of impurities such as residual solvent falls below a certain level, but usually 100% residual solvent is used.
Dry for not less than 0 ppm, preferably not more than 300 ppm, more preferably not more than 100 ppm.

The electrophotographic photoreceptor, which is the application of the polyester resin of the present invention, will be described in detail below. The electrophotographic photoreceptor in which the resin of the present invention is used usually has a photosensitive layer on a conductive support, and examples of the conductive support include aluminum, aluminum alloys, stainless steel, copper,
The surface of a metal material such as nickel or the like, a resin material to which conductivity is added by adding a conductive powder such as metal, carbon or tin oxide, or a conductive material such as aluminum, nickel or ITO (indium tin oxide oxide alloy) Resin, glass, paper, etc. vapor-deposited or applied on are mainly used. As the form, a drum form, a sheet form, a belt form and the like are used. A conductive material having an appropriate resistance value may be applied on a conductive support made of a metal material in order to control the conductivity and surface properties and to cover defects.

When a metal material such as an aluminum alloy is used as the conductive support, it may be used after being subjected to anodic oxidation treatment, chemical conversion coating treatment and the like. When the anodizing treatment is performed, it is desirable to perform the sealing treatment by a known method. The surface of the support may be smooth, or may be roughened by using a special cutting method or polishing treatment. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material forming the support.

An undercoat layer may be provided between the conductive support and the photosensitive layer in order to improve adhesiveness, blocking property and the like. As the undercoat layer, a resin, a resin in which particles of a metal oxide or the like are dispersed, or the like is used. Examples of the metal oxide particles used for the undercoat layer include metal oxide particles containing one kind of metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, and titanium. Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid salt and barium titanate. Only one type of particles may be used, or a plurality of types of particles may be mixed and used. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide or silicon oxide, or an organic substance such as stearic acid, polyol or silicone. As the crystal type of titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. A plurality of crystalline states may be included.

As the particle size of the metal oxide particles, various ones can be used. Among them, the average primary particle size is preferably 10 to 100 nm, and particularly preferably, from the viewpoints of characteristics and liquid stability. It is 10 to 25 nm. The undercoat layer is preferably formed by dispersing metal oxide particles in a binder resin. As the binder resin used in the undercoat layer, phenoxy, epoxy, polyvinylpyrrolidone, polyvinyl alcohol, casein, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, etc. may be used alone or with a curing agent. Among them, alcohol-soluble copolyamides, modified polyamides and the like are preferable because they exhibit good dispersibility and coatability.

The addition ratio of the inorganic particles to the binder resin can be arbitrarily selected, but it is preferable to use it in the range of 10 to 500% by weight from the viewpoint of stability and coating property of the dispersion liquid. The thickness of the undercoat layer can be arbitrarily selected, but is preferably 0.1 to 20 μm in view of the characteristics of the photoreceptor and the coating property. Further, a known antioxidant or the like may be added to the undercoat layer.

Specific structures of the photosensitive layer of the electrophotographic photosensitive member include: a charge generating layer containing a charge generating substance as a main component on a conductive support, a charge transporting substance containing a charge transporting substance and a binder resin as a main component. A laminated photoreceptor in which layers are laminated in this order. An inverse two-layer type photoreceptor in which a charge transporting layer containing a charge transporting substance and a binder resin as main components and a charge generating layer containing a charge generating substance as a main component are laminated in this order on a conductive support. A single-layer type (dispersion type) photoreceptor in which a layer containing a charge transport substance and a binder resin is laminated on a conductive support, and the charge generating substance is dispersed in the layer. Etc. are mentioned as an example of the basic form.

In the case of a laminated type photoreceptor, examples of the charge generating substance used in the charge generating layer include selenium and its alloys, cadmium sulfide, and other inorganic photoconductive materials.
Various photoconductive materials such as organic pigments such as phthalocyanine pigments, azo pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments can be used, particularly organic pigments, and further phthalocyanine pigments, azo pigments. Is preferred.

Among them, metal-free phthalocyanines, copper, indium, gallium, tin, titanium, zinc, vanadium and other metals or their oxides, phthalocyanines coordinated with chlorides, azo such as monoazo, bisazo, trisazo and polyazos. Pigments are preferred. When using a phthalocyanine compound as the charge generating substance of the electrophotographic photosensitive member, specifically, a metal-free phthalocyanine, a metal such as copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, or an oxide thereof, Coordinated phthalocyanines such as halides are used. Examples of the ligand to the metal atom having a valence of 3 or more include a hydroxyl group and an alkoxy group in addition to the oxygen atom and chlorine atom shown above. Particularly preferred are X-type and τ-type metal-free phthalocyanines, α-type, β-type, and Y-type titanyl phthalocyanines, vanadyl phthalocyanines, chloroindium phthalocyanines, chlorogallium phthalocyanines, and hydroxygallium phthalocyanines, which are particularly sensitive. Among the crystalline forms of titanyl phthalocyanine listed here, α type and β type are described in W. Phase II, I by Heller et al.
It is shown as a phase (Zeit.Kristallogr.159 (1982) 17
3), β type is known as stable type. The most preferably used Y type is powder X using CuKα ray.
In the line diffraction, the crystalline form is characterized by a clear peak at a diffraction angle 2θ ± 0.2 ° of 27.3 °. As the phthalocyanine compound, only a single compound may be used, or some of them may be mixed. As a phthalocyanine compound or a mixed state which can be placed in a crystalline state here, the respective constituents may be mixed and used afterwards, or the mixed state may be changed in the production / treatment step of the phthalocyanine compound such as synthesis, pigmentation and crystallization. It may be something that has occurred. Examples of such treatment include acid paste treatment and
Grinding treatment, solvent treatment, etc. are known.

Examples of these charge generating substances include polyester resin, polyvinyl acetate, polyacrylic acid ester, polymethacrylic acid ester, polycarbonate,
It is used in the form of being bound with various binder resins such as polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin, urethane resin, cellulose ester and cellulose ether. In this case, the charge generating substance is used in an amount of usually 20 to 2000 parts by weight, preferably 30 to 500 parts by weight, and more preferably 3 to 100 parts by weight of the binder resin.
It is in the range of 3 to 500 parts by weight.

If desired, other organic photoconductive compounds, dye pigments and electron withdrawing compounds may be contained.
The thickness of the charge generation layer is usually 0.05 to 5 μm, preferably 0.1 to 2 μm, more preferably 0.15 to 0.8 μm.
Is preferred. The charge transport layer of the electrophotographic photosensitive member is mainly composed of a charge transport substance and a binder resin. As the binder resin, the above polyester resin is mainly used.

These charge transport materials include 2, 4,
Aromatic nitro compounds such as 7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, electron withdrawing substances such as quinones such as diphenoquinone, carbazole derivatives, indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, oxa Heterocyclic compounds such as diazole derivatives, pyrazoline derivatives, and thiadiazole derivatives, aniline derivatives, hydrazone compounds, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine compounds, compounds in which a plurality of these compounds are bound, or from these compounds Electron-donating substances such as polymers having the following groups in the main chain or side chains. Among these, a carbazole derivative, a hydrazone derivative, an aromatic amine derivative, a stilbene derivative, a butadiene derivative and a compound in which a plurality of these derivatives are bonded are preferable, and a compound in which a plurality of aromatic amine derivatives, a stilbene derivative and a butadiene derivative are bonded in combination Is particularly preferable.

These charge transport materials may be used alone or in combination of two or more. The charge transport layer is formed by binding these charge transport materials to the binder resin. The charge transport layer may be composed of a single layer, or may be a stack of a plurality of layers having different constituents or composition ratios. The ratio of the binder resin to the charge transport material in the charge transport layer is usually 30 to 200 parts by weight, but preferably 40 to 150 parts by weight or less, based on 100 parts by weight of the binder resin. The upper limit of 90 parts by weight or less is advantageous for maintaining the mechanical properties of the polyester resin. The film thickness is generally 10 to 60 μm, preferably 10 to 45 μm,
More preferably, it is 27 to 40 μm.

The charge transport layer has film-forming properties, flexibility, coating properties,
Additives such as well-known plasticizers, antioxidants, ultraviolet absorbers, electron-withdrawing compounds, leveling agents, and sensitizers may be added to improve stain resistance, gas resistance, light resistance and the like. . Examples of the electron-withdrawing compound include quinones such as chloranil, 2,3-dichloro-1,4-naphthoquinone, 1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone and phenanthrenequinone; 4- Aldehydes such as nitrobenzaldehyde; 9-benzoylanthracene, indandione, 3,5-dinitrobenzophenone, 2,4,7-
Ketones such as trinitrofluorenone, 2,4,5,7-tetranitrofluorenone and 3,3 ′, 5,5′-tetranitrobenzophenone; acid anhydrides such as phthalic anhydride and 4-chloronaphthalic anhydride; Cyano compounds such as tetracyanoethylene, terephthalalmalononitrile, 9-anthrylmethylidene malononitrile, 4-nitrobenzalmalononitrile, 4- (p-nitrobenzoyloxy) benzalmalononitrile; 3-benzalphthalide, 3- (Α-cyano-p-nitrobenzal) phthalide, 3- (α-cyano-p-nitrobenzal) -4,
Examples thereof include electron-withdrawing compounds such as phthalides such as 5,6,7-tetrachlorophthalide.

Examples of antioxidants include hindered phenol compounds and hindered amine compounds. Examples of dye pigments that are optionally added to the photosensitive layer of the electrophotographic photoreceptor include triphenylmethane dyes such as methyl violet, brilliant green, and crystal violet, thiazine dyes such as methylene blue, quinone dyes such as quinizarin, and cyanine dyes and pyrylium. Examples thereof include salts, thiapyrylium salts and benzopyrylium salts.

The photosensitive layer of the electrophotographic photoreceptor is prepared by dissolving a charge transporting substance together with a binder resin containing a polyester resin in a suitable solvent according to a conventional method, and if necessary, a suitable charge generating substance, sensitizing dye, electron By forming a photosensitive layer by coating a coating solution obtained by adding a well-known additive such as an attractant compound, another charge transporting substance, or a plasticizer or a pigment, and drying it on a conductive support. It can be manufactured. In the case of a photosensitive layer composed of two layers of a charge generation layer and a charge transport layer, the above-mentioned coating liquid is applied onto the charge generation layer, or the charge generation layer is applied onto the charge transport layer obtained by applying the above-mentioned coating liquid. It can be manufactured by forming.

As the solvent for preparing the coating solution, ethers such as tetrahydrofuran, 1,4-dioxane, ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; N, N-dimethylformamide, acetonitrile, N-methylpyrrolidone,
Aprotic polar solvents such as dimethyl sulfoxide; esters such as ethyl acetate, methyl formate and methyl cellosolve acetate; solvents that dissolve amine compounds such as chlorinated hydrocarbons such as dichloroethane and chloroform. Of course, it is necessary to select one that dissolves the binder from these.

The photosensitive layer of the electrophotographic photosensitive member has a film-forming property,
A well-known plasticizer may be contained in order to improve flexibility and mechanical strength. Therefore, examples of the plasticizer added to the coating solution include phthalic acid esters, phosphoric acid esters, epoxy compounds, chlorinated paraffins, chlorinated fatty acid esters, and aromatic compounds such as methylnaphthalene. When the arylamine-based compound is used as the charge-transporting substance in the charge-transporting layer, the coating solution may have the above composition, but the photoconductive particles, dye pigment, electron-withdrawing compound, etc. may be removed or added in a small amount. Good. In this case, as the charge generation layer, a coating liquid obtained by dissolving or dispersing in the solvent such as the above-mentioned photoconductive particles and optionally a binder polymer or other organic photoconductive substance, dye pigment, electron-withdrawing compound is applied. Examples thereof include a dried thin layer or a layer formed by film-forming the photoconductive particles.

A protective layer may be provided on the photosensitive layer for the purpose of preventing wear of the photosensitive layer and preventing / reducing deterioration of the photosensitive layer due to discharge products generated from a charger or the like. Also, for the purpose of reducing the frictional resistance of the photoconductor surface and wear,
The surface layer may contain a fluorine resin, a silicone resin, or the like. Further, particles made of these resins or particles of an inorganic compound may be included.

It is needless to say that a barrier layer, an adhesive layer, an intermediate layer such as a blocking layer, a transparent insulating layer or the like may be added as necessary to improve the electrical and mechanical properties. Absent. Examples of the coating method of the photosensitive layer include a spray coating method, a spiral coating method, a ring coating method and a dip coating method.

As a spray coating method, air spray,
There are airless spray, electrostatic air spray, electrostatic airless spray, rotary atomizing electrostatic spray, hot spray, hot airless spray, etc., but considering the atomization degree to obtain a uniform film thickness, adhesion efficiency, etc. In the rotary atomization type electrostatic spray, by the conveying method disclosed in the republication No. 1-805198, that is, by continuously conveying the cylindrical work without any interval in the axial direction while rotating it, It is possible to obtain an electrophotographic photosensitive member having a high adhesion efficiency and excellent film thickness uniformity.

A spiral coating method is disclosed in JP-A-52-
A method using a liquid injection coating machine or a curtain coating machine disclosed in Japanese Patent No. 119651, Japanese Patent Laid-Open No. 231966/1989.
Japanese Patent Laid-Open No. 3-193161 discloses a method using a multi-nozzle body for continuously ejecting paint in a streak pattern from a minute opening.

The dip coating method will be described below. Using a charge transport material (preferably the aforementioned compound), a polyester resin, a solvent, etc., the total solid content concentration is usually 25 to 40.
%, The viscosity is usually 50 to 300 centipoise, preferably 100 to 200 centipoise. A coating solution for forming the charge transport layer is prepared. Here, the viscosity of the coating solution is substantially determined by the type of binder polymer and its molecular weight,
If the molecular weight is too low, the mechanical strength of the polymer itself decreases, so it is preferable to use a binder polymer having a molecular weight that does not impair the mechanical strength. The charge transport layer is formed by the dip coating method using the coating liquid prepared as described above.

After that, the coating film is dried, and the drying temperature time may be adjusted so that necessary and sufficient drying is performed. The drying temperature is usually 100 to 250 ° C., preferably 110 to 17
0 ° C., more preferably 120 to 140 ° C. As a drying method, a hot air dryer, a steam dryer, an infrared dryer, a far infrared dryer or the like can be used.
The electrophotographic photoreceptor thus obtained is highly sensitive, has a low residual potential and a high charging property, and has a small fluctuation due to repetition, and in particular, has a good charging stability that affects the image density. It can be used as a highly durable photoreceptor. Further, since the sensitivity in the region of 750 to 850 nm is high, it is particularly suitable for a photoconductor for a semiconductor laser printer.

An electrophotographic apparatus such as a copying machine or a printer using the electrophotographic photosensitive member of the present invention is at least charged,
Although each process of exposure, development, and transfer is included, any process may be used as a commonly used method. As the charging method (charger), any of corotron or scorotron charging using corona discharge, contact charging with a conductive roller or brush, film, etc. may be used. Among them, in the charging method using corona discharge, scorotron charging is often used to keep the dark part potential constant. As a developing method, a general method of developing by contacting or non-contacting a magnetic or non-magnetic one-component developer, a two-component developer or the like is used. The transfer method may be corona discharge, a method using a transfer roller or a transfer belt, or the like. The transfer may be performed directly on the paper, the OHP film, or the like, or may be performed once on the intermediate transfer body (belt-shaped or drum-shaped) and then transferred on the paper or the OHP film.

Usually, after the transfer, a fixing process for fixing the developer on paper or the like is used, and as the fixing means, generally used heat fixing, pressure fixing, etc. can be used. In addition to these processes, it is also possible to have processes such as cleaning and charge removal that are commonly used.

[0054]

EXAMPLES Hereinafter, specific embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples unless the gist thereof is exceeded. [Production of Polyester Resin] Production Example 1 (Production Method of Polyester Resin of Example 1) Sodium hydroxide (5.20 g) and water (400 ml) were weighed in a 1 L beaker and dissolved by stirring while bubbling nitrogen. 4-tert-butylphenol (0.2173 g), benzyltriethylammonium chloride (0.0647 g) and bis (4-hydroxy-3,5-dimethylphenyl) methane [= TmBP]
F] (6.31 g) and a bisphenol compound [= p, p'-BPF] (4.93 g) shown below in this order,
After stirring, this alkaline aqueous solution was transferred to a 2 L reaction tank.

[0055]

[Chemical 8]

Separately, terephthalic acid chloride (5.07
g) and isophthalic acid chloride (5.07 g) were dissolved in dichloromethane (200 ml) and transferred into a dropping funnel. While keeping the external temperature of the polymerization tank at 20 ° C., the dichloromethane solution was added dropwise from the dropping funnel over 1 hour while stirring the alkaline aqueous solution in the reaction tank. After stirring for another 3 hours, acetic acid (1.71 ml), dichloromethane (100
ml) and water (50 ml) were added and stirred for 30 minutes. Then, the stirring was stopped and the organic layer was separated. This organic layer was
The mixture was poured into a 1N sodium hydroxide aqueous solution (450 ml), stirred, separated, and washed, and then 0.1N hydrochloric acid (450 m
It was washed twice with 1) and further twice with water (450 ml).

200 ml of methylene chloride was added to the organic layer after washing.
Was added to dilute, and the mixture was poured into methanol (1500 ml) to obtain a precipitate, which was taken out by filtration and dried to obtain a target polyester resin. The viscosity average molecular weight of the obtained polyester resin was 40,000. The structural formula of the obtained polyester resin is shown below.

[0058]

[Chemical 9]

[Measurement of viscosity average molecular weight] A polyester resin was dissolved in dichloromethane to prepare a solution having a concentration C of 6.00 g / L. Flow time t of solvent (dichloromethane)
_Using a Ubbelohde-type capillary viscometer with ₀ of 136.16 seconds, the flow time t of the sample solution was measured in a constant temperature water bath set at 20.0 ° C. The viscosity average molecular weight M according to the following formula
v was calculated.

[0060]

## EQU1 ## a = 0.438 × η _sp +1 η _sp = t / t ₀ -1 b = 100 × η _sp / C C = 6.00 (g / L) η = b / a Mv = 3207 × η ^1.205 Production Examples 2, 3, 6 and Comparative Production Examples 1 to 3 (Methods for producing polyester resins of Examples 2, 3, 6 and Comparative Examples 1 to 3) The monomer composition ratios in Production Example 1 are shown in Table 1.
A polyester resin was produced in the same manner as in Production Example 1 except that the copolymer composition was changed to the same composition shown in FIG. The viscosity average molecular weight of the obtained polyester resin is shown in Table 1. The polyester resin having the composition of Comparative Example 3 was insoluble in methylene chloride, and the viscosity average molecular weight could not be measured.

Production Examples 4 and 5 (Production Method for Polyester Resins of Examples 4 and 5) Instead of [p, p'-BPF] of Production Example 1, o, o'-BPF or o, p 'having the following structure: -Table 1 for each BPF
A polyester resin was produced in the same manner as in Production Example 1 except that the composition was changed to the same compositional ratio as shown in Examples 4 and 5. The viscosity average molecular weight of the obtained polyester resin is shown in Table 1.

Example 1 Production of Photoreceptor (Production of Charge Generation Layer) 10 parts by weight of β-type oxytitanium phthalocyanine having the following structure was added to 4-methoxy-4.
-Methylpentanone-2 In addition to 150 parts by weight, pulverization and dispersion treatment was performed with a sand grind mill.

[0063]

[Chemical 10]

100 parts of a 5% 1,2-dimethoxyethane solution of polyvinyl butyral (produced by Denki Kagaku Kogyo KK, trade name Denka Butyral # 6000C) and phenoxy resin (produced by Union Carbide, trade name PKH
A binder solution was prepared by mixing 100 parts of a 5% 1,2-dimethoxyethane solution of H). 160 parts by weight of the pigment dispersion liquid prepared above, 100 parts by weight of the binder solution,
An appropriate amount of 1,2-dimethoxyethane was added to finally prepare a dispersion liquid having a solid content concentration of 4.0%.

The dispersion thus obtained was coated on a polyethylene terephthalate film having aluminum vapor-deposited on its surface so as to have a film thickness of 0.4 μm, to form a charge generation layer. (Production of Charge Transport Layer) Pigment Dispersion Liquid 16 Produced Above
0 parts by weight, 100 parts by weight of the binder solution, and a suitable amount of 1,
2-dimethoxyethane was added and the final solids concentration was 4.0.
% Dispersion was prepared.

The dispersion liquid thus obtained was coated on a polyethylene terephthalate film having aluminum vapor-deposited on its surface so as to have a thickness of 0.4 μm to form a charge generation layer. (Production of charge transport layer) Next, on this film, the following charge transport material [1] (where the phenylbutadiene chain on the left side is one of the two benzene rings on the left side in parentheses, and the phenylbutadiene on the right side is (The chain is attached to one of the two benzene rings on the right in parentheses.)
A solution prepared by dissolving 50 parts by weight, 100 parts by weight of the polyester resin obtained in Production Example 1 and 0.03 part by weight of silicone oil as a leveling agent in a mixed solvent of toluene / tetrahydrofuran (weight ratio 2/8) was prepared. Apply and dry at 125 ° C for 20 minutes, and the film thickness after drying is 20μ
The charge transport layer was provided so as to have m. At this time, the solubility of the polyester resin was good. The photoreceptor thus obtained was evaluated as follows.

[0067]

[Chemical 11]

[Electrical Characteristics] Electrophotographic characteristic evaluation device manufactured according to the measurement standard of the Electrophotographic Society (Continued Basics and Applications of Electrophotographic Technology, edited by The Electrophotographic Society, Corona Publishing Co., 404-40.
(Described on page 5), the above-mentioned photoreceptor is attached to an aluminum drum to form a cylindrical shape, the aluminum drum and the aluminum base of the photoreceptor are electrically connected, and then the drum is rotated at a constant rotation speed. An electrical characteristic evaluation test was performed by a cycle of charging, exposure, potential measurement, and static elimination. that time,
The initial surface potential is set to -700 V, monochromatic light of 780 nm is used for exposure and 660 nm is used for static elimination, and light of 780 nm is 2.
The surface potential (VL) at the time of irradiation with 4 μJ / cm ² was measured. At the time of VL measurement, the time required for exposure-potential measurement was set to 139 ms. The measurement environment was 25 ° C. and 50% relative humidity (N / N) and 5 ° C. and 5% relative humidity (LL). The results are shown in Table 1. The smaller the absolute value of the surface potential (VL) value, the better the response.

[Abrasion test] A photoreceptor film having a diameter of 10c
Taber abrasion tester (made by Toyo Seiki Co., Ltd.)
The wear was evaluated by. The test conditions are 23 ° C. and 50
Using an abrasion wheel CS-10F under an atmosphere of% RH, the abrasion amount after 1000 rotations without load (the abrasion wheel's own weight) was measured by comparing the weights before and after the test. The results are shown in Table 1.

[Friction Test] A urethane rubber of the same material as the cleaning blade was cut to a width of 1 cm on the surface on which the toner was evenly placed so as to be in contact with the photosensitive member prepared above in an amount of 0.1 mg / cm ^2. Used at an angle of 45 degrees, load 200 g, speed 5 mm / sec, stroke 2
10 when urethane rubber is moved 100 times at 0 mm
The zero-time dynamic friction coefficient was measured with a fully automatic friction and wear tester DFPM-SS manufactured by Kyowa Interface Science Co., Ltd. The results are shown in Table 1. Examples 2 to 6 Examples except that the polyester resin shown in Examples 2 to 6 in Table 1 was used in place of the polyester resin in the production of the photoconductor (production of the charge transport layer) in Example 1 The same operation as in 1 was performed to produce a photoconductor. The abrasion test and the evaluation of electric characteristics of the obtained photoconductor were carried out by the same method as in Example 1 under the same conditions. The results are shown in Table 1. Comparative Examples 1 and 2 In place of the polyester resin used in the production of the photoconductor (production of the charge transport layer) in Example 1, the polyester resins shown in Comparative Examples 1 and 2 in Table 1 were used, and the same operation as in Example 1 was performed. Then, a photoconductor was manufactured. The abrasion test and the evaluation of electric characteristics of the obtained photoconductor were carried out by the same method as in Example 1 under the same conditions. The results are shown in Table 1. Comparative Example 3 The same operation as in Example 1 was performed using the polyester resin shown in Comparative Example 3 in Table 1 in place of the polyester resin in the production of the photoreceptor (production of the charge transport layer) in Example 1.
An attempt was made to produce a photoconductor, but the polyester resin was insoluble in either THF / toluene or 1,2-dichloroethane, and the photoconductor could not be produced.

[0071]

[Table 1]

Solubility: Solubility in THF / toluene (8/2 weight ratio) ○ Soluble (no precipitation for one month or more) △ Soluble (solidified the next day) × Insoluble friction test Taber abrasion test After 1000 rotations Abrasion amount (mass decrease) Electric characteristics Smaller VL value means better electric characteristics Measurement environment condition NN: 25 ° C, 50% RH LL: 5 ° C, 10% RH Dicarboxylic acid component constituting binder resin TPA : Terephthalic acid, IPA: isophthalic acid The structural formulas of the monomers (diol components) constituting the binder resin are shown below.

[0073]

[Chemical 12]

From the results shown in Table 1, it can be seen that the use of the polyester resin of the present invention as a binder makes it possible to obtain an electrophotographic photoreceptor having excellent electrical properties and mechanical properties.

[0075]

INDUSTRIAL APPLICABILITY The polyester resin of the present invention has good solubility in a coating solvent and excellent liquid stability of a coating liquid, and when it is used as a binder resin, it has excellent electrical properties, abrasion resistance and slipperiness in electrophotography. Photosensitivity can be obtained.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Chiyoko Sato             1000 Kamoshida-cho, Aoba-ku, Yokohama-shi, Kanagawa             Within Mitsubishi Chemical Corporation (72) Inventor, Shoteru Fujii             1000 Kamoshida-cho, Aoba-ku, Yokohama-shi, Kanagawa             Within Mitsubishi Chemical Corporation (72) Inventor protection             1000 Kamoshida-cho, Aoba-ku, Yokohama-shi, Kanagawa             Within Mitsubishi Chemical Corporation F-term (reference) 2H068 AA13 BB26 BB53

Claims (5)

[Claims] 1. An electrophotographic photoreceptor having at least a photosensitive layer on a conductive substrate, wherein the binder resin of the photosensitive layer has a polyester structure represented by the following general formula (1). Photoconductor. [Chemical 1] (In the general formula (1), A represents a divalent organic group, and X is one kind selected from the group represented by the following structural formulas (A), (B), and (C). A is the following structural formula. (A), (B),
None of (C). [Chemical 2] However, when X is the structural formula (A), 0.01 ≦ m / (m +
n) <0.9, and when X is the structural formula (B) or the structural formula (C), 0.01 ≦ m / (m + n) ≦ 1. ) 2. m and n in the general formula (1) are 0.1 ≦ m.
The electrophotographic photosensitive member according to claim 1, wherein /(n+m)≦0.70. 3. The electrophotography according to claim 1, wherein the dicarboxylic acid component is terephthalic acid or a mixture of terephthalic acid and isophthalic acid, and the molar ratio of terephthalic acid to the total amount of dicarboxylic acid component is 50% or more and 100% or less. Photoconductor. 4. The electrophotographic photosensitive member according to claim 1, wherein A in the general formula (1) has a structure represented by the following structural formula (D). [Chemical 3] 5. X in the general formula (1) is the structural formula (A), and n and m in the general formula (1) are 0.1 ≦ m / (m
The electrophotographic photosensitive member according to claim 1, wherein + n) ≦ 0.40.