JP2729741B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor having a layer structure in which a charge generation layer and a charge transport layer are functionally separated, and more particularly to the charge transport. It relates to the composition of the layer. 2. Description of the Related Art Conventionally, electrophotographic photoreceptors include a single photoconductive layer and a stacked photoconductive layer. In particular, in recent years, an organic photoconductive material has been bound as a photoconductive layer with a resin or the like. Various proposals have been made regarding an organic electrophotographic photoreceptor having a layer configuration in which a charge transport layer and a charge generation layer are functionally separated.
(For example, JP-A-56-52756 and JP-A-57-52756)
73743). Further, as for the binder resin in the charge transport layer, polycarbonate resin, polyester resin, those using polymethyl methacrylate resin,
Alternatively, a device using bisphenol Z polycarbonate resin (JP-A-59-71057) has been proposed. [0003] When such an electrophotographic photosensitive member comprising an organic photoconductive material and a binder resin is applied to a usual electrophotographic process such as the Carlson method, there are various problems. There was a problem. For example, when a specific resin is used as a binder resin of a charge generation material, the binder resin forms a charge transfer complex with a charge transport agent, and as a photoreceptor, no charge is made, or There is a disadvantage that the charge transport agent is deteriorated due to the change and causes so-called light fatigue. Further, for example, in the case of a photoreceptor having a charge transporting layer composed of a charge transporting agent and a binder resin disposed thereon, the toner adheres to the surface of the charge transporting layer, and the developer or transfer paper and the photoreceptor surface There are problems such as abrasion and scratches caused by contact with the substrate, and as a solution to these problems, when a polycarbonate resin, a polyester resin, a polymethyl methacrylate resin, or the like is used as a binder resin in the charge transport layer. On the other hand, the electrophotographic characteristics were not yet sufficiently satisfactory.
Further, when a bisphenol Z polycarbonate resin is used, there is a drawback that a specific charge transporting agent is not charged at all. [0004] An object of the present invention is to improve the problems in the prior art as described above. That is, one of the objects of the present invention is to provide an electrophotographic photosensitive member that is clearly charged and has good sensitivity. Another object of the present invention is to provide an electrophotographic photoreceptor which does not cause deterioration over time in chargeability, sensitivity and the like. Still another object of the present invention is to provide an electrophotographic photoreceptor that satisfies both electrical durability such as charging property and sensitivity and mechanical durability such as friction resistance and toner filming property. Means for Solving the Problems The inventors of the present invention have made intensive studies on compounds having a charge transporting property, and as a result, have the following general formula (I):
When a group of compounds represented by is used together with a specific binder resin, they were not adversely affected by the binder resin, and were found to exhibit excellent electrophotographic properties as a charge transporting agent, and completed the present invention. . The electrophotographic photoreceptor of the present invention comprises, on a conductive substrate, a compound represented by the following general formula (I), (a) a bisphenol Z carbonate resin, (b) a polyester carbonate resin, and (c) Polyarylate resin, (d)
A photosensitive layer containing a mixture of bisphenol Z polycarbonate resin and polyester carbonate resin or (e) a mixture of bisphenol Z polycarbonate resin and polyarylate resin is provided. Embedded image (In the formula, R ₁ represents an alkyl group, and R ₂ and R ₃ each represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen group, an alkoxycarbonyl group or a substituted amino group.) More specifically, as the conductive base in the electrophotographic photoreceptor of the present invention, a conventionally known conductive base can be used as it is, for example, a metal plate such as aluminum, a metal foil, or a metal such as a metal on a plastic film. A material obtained by vapor deposition or application of a conductive substance can be used. In the present invention, the photosensitive layer provided on the conductive substrate may be composed of a single layer, or may have a layer structure in which a charge generation layer and a charge transport layer are functionally separated. Is also good. Among the compounds represented by the general formula (I) to be contained in the photosensitive layer in the present invention, preferred are the compounds represented by the following general formulas (II) and (III). Embedded image (Wherein, R ₄ and R ₅ each represent a hydrogen atom or a methyl group.) (In the formula, one of R ₆ and R ₇ represents an alkyl group having 2 or more carbon atoms, and the other represents a hydrogen atom, an alkyl group, an alkoxy group, or a substituted amino group.) These are compounds represented by the following structural formulas (IV) and (V). Embedded image The compound represented by the general formula (III) has an extremely high solubility in a solvent, for example, high solubility in toluene, chlorobenzene, 1,1,2-trichloroethane, tetrahydrofuran, 1,4-dioxane, cyclohexanone and the like. Has solubility. For example, the solubility of the compounds represented by the structural formulas (IV) and (V) in toluene and chlorobenzene is as shown in Table 1 below, and has higher solubility than the others. [Table 1] Therefore, when these compounds are used, the amount introduced into the coating solution for forming a photosensitive layer can be increased. In addition, these compounds have the advantage that the viscosity of the coating solution can be increased, and thus the charge transport layer can be made thicker and the dripping after coating can be reduced. Formula (I)
Specific examples of the compound represented by the formula (I)
In addition to (V) and (V), the following may be mentioned. Embedded image Embedded image Embedded image Embedded image (In the formula, Me represents CH ₃ , Et represents C ₂ H ₅ , Pr represents C ₃ H ₇ , and Bu represents C ₄ H ₉ ) In the present invention, the photosensitive layer has a binder. As the resin, bisphenol Z carbonate resin, polyester carbonate resin, polyarylate resin, a mixture of bisphenol Z polycarbonate resin and polyester carbonate resin, or a mixture of bisphenol Z polycarbonate resin and polyarylate resin is used. When it has a structure, it is particularly preferable to use these binder resins in the charge transport layer.
In the present invention, when the photosensitive layer comprises a single layer, the compound represented by the general formula (I) is preferably contained in an amount of 50 to 180% by weight based on the binder resin. In this case, the photosensitive layer also contains a charge generating material, and the charge generating material is added in an amount of 2 to 30% by weight, preferably 5 to 15% by weight, based on the binder resin. Known charge generation materials can be used as they are. For example, examples of the inorganic charge generating agent include selenium, trigonal selenium, selenium tellurium, selenium-arsenic, cadmium sulfide-selenium, and cadmium sulfide. Examples of organic charge generating agents include squarylium dyes, azo pigments such as monoazo pigments, bisazo pigments, and trisazo pigments, phthalocyanine pigments such as metal-free phthalocyanines and metal phthalocyanines, dibenzpyrenequinone pigments, pyranthrone pigments, Examples include polycyclic quinone pigments such as anthrones, and perylene pigments such as perylene anhydride and perylene imide. These charge generating agents can be used in combination with various sensitizers as needed. In the present invention, when the photosensitive layer has a layer structure in which a function is separated into a charge generation layer and a charge transport layer, the compound represented by the general formula (I) is contained in the charge transport layer. 10 to 80 with respect to the total solid portion of the charge transfer layer
%. In the case where the photosensitive layer has a layer structure in which the charge generation layer and the charge transport layer are functionally separated, the binder resin in the charge generation layer is not limited to the above-mentioned binder resin, but may have other film forming properties. Can also be used, for example, polyarylate resin, polysulfone resin, polyamide resin, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenolic resin, epoxy resin, alkyd resin, bisphenol A type polycarbonate, Polyurethane, or a copolymer resin composed of two or more vinyl monomers, for example, styrene-butadiene copolymer, styrene-acrylonitrile copolymer,
There are styrene-maleic acid copolymers and the like, and photoconductive poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene and the like can also be used. In the present invention, when the binder resin in the charge transport layer is an ester resin selected from the group consisting of bisphenol Z polycarbonate resin, polyester carbonate resin and polyarylate resin,
It is particularly preferable because it simultaneously satisfies electrical durability such as charging property and sensitivity and mechanical durability such as friction resistance and toner filming property. These binder resins are also preferably used as a mixture of a bisphenol Z polycarbonate resin and a polyester carbonate resin, or a mixture of a bisphenol Z polycarbonate resin and a polyarylate resin. The binder resins will be described more specifically. Bisphenol Z polycarbonate has the following basic units. Embedded image The polyester carbonate resin has, for example, the following basic structural units. Embedded image (Wherein R ₈ and R ₉ are each a hydrogen atom, an acyl group,
Represents an alkyl group or a phenyl group, or represents a group in which R ₈ and R ₉ are combined to form a ring, X _{1 to} X ₄ each represent a hydrogen atom, an alkyl group or a halogen atom, and m represents an integer. Represent. The polyarylate resin has, for example, the following basic structural units. Embedded image (In the formula, R ₈ , R ₉ and X _{1 to} X ₄ have the same meanings as described above.) A bisphenol Z polycarbonate resin, polyester carbonate resin and polyarylate resin used as a binder resin of the above compound Is used in terms of molecular weight in the range of 10,000 to 150,000, preferably 20,000 to 15
In the range of 0,000, more preferably 25,000
１００100,000. Specific examples of these binder resins include the following in addition to the above-mentioned bisphenol Z polycarbonate resin. Examples of the polyester carbonate resin having the basic structural unit represented by the general formula (VII) include the following. Note that m and n
Means the degree of polymerization. Embedded image Embedded image Embedded image Further, specific examples of the polyarylate resin having a basic structural unit represented by the above general formula (VIII) include:
These include: In addition, m and n mean the degree of polymerization. Embedded image In the present invention, as the charge generation material used for the charge generation layer, known materials can be used as they are. These charge generating agents can be used in combination with various resins and sensitizers as needed. In the electrophotographic photoreceptor of the present invention, when the photosensitive layer has a layer configuration in which a charge generation layer and a charge transport layer are functionally separated, the charge generation layer and the charge transport layer are not clearly separated, and the charge The composition may change continuously from the generation region to the charge transport region. Furthermore, either the charge generation layer or the charge transport layer may be provided on the upper layer. When the charge generation layer is provided on the upper layer, the photoreceptor is of a positive charge type, and when the charge transport layer is provided on the upper layer. -Can be used as a charging type. In the electrophotographic photoreceptor of the present invention, the thickness of the charge generation layer is preferably set to 5 μm or less, more preferably 2 μm or less. The charge transport layer has a thickness of 3 to 5
It is desirable to set the thickness to 0 μm, preferably 5 to 25 μm. Further, the electrophotographic photoreceptor of the present invention may be provided with a protective layer, an adhesive layer, and the like as necessary. Hereinafter, the present invention will be described with reference to Examples.
The present invention is not limited by these examples. Examples 1 to 3 and Comparative Examples 1 to 4 3.0 g of a charge transport agent shown in Table 2 below, 3.0 g of a binder resin shown in Table 2 below, and 34.0 g of methylene dichloride.
A solution comprising Tri-Se provided on a conductive substrate
/ Polyvinylcarbazole was applied to a thickness of 25 μm on a charge generation layer and dried at 80 ° C. for 2 hours to produce an electrophotographic photosensitive member. The electrical characteristics (E1 / 4) of this photoreceptor were measured with SP428 manufactured by Kawaguchi Electric Co., Ltd., and the results shown in Table 2 were obtained. In the table below, PC (Z) is a bisphenol Z type polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., MW5400).
0), PEC indicates a polyester carbonate resin (C300A, manufactured by Mitsubishi Kasei Co., Ltd.), and PA indicates a polyarylate resin (U-polymer U-1, manufactured by Unitika Ltd.)
00). [Table 2] Example 4 An electrophotographic photoreceptor was produced in the same manner as in Examples 1 to 3, using the charge transporting agents and the binder resins shown in Table 3 below.
The electrical characteristics (E1 / 4) were measured. The results were as shown in Table 3. [Table 3] Example 5 An electrophotographic photosensitive member was produced in the same manner as in Examples 1 to 3, except that 3 g of a compound represented by the following structural formula was used. When this electrophotographic photosensitive member was evaluated in the same manner, almost the same results were obtained. Embedded image Comparative Example 5 and Example 6 3 g of a compound represented by the following structural formula, polycarbonate A
A solution obtained by dissolving 3 g of (Macrolon 5705 manufactured by Bayer AG) in 34 g of methylene chloride is charged on a conductive substrate with Tri-Se (trigonal selenium) / polyvinylcarbazole (trigonal selenium 7% by volume). Apply on the generating layer (film thickness 2.5 μm) with an applicator,
After drying at 0 ° C. for 2 hours, an electrophotographic photosensitive member was manufactured. (Film thickness 25 μmm) (Comparative Example 5 ) An electrophotographic photosensitive member was prepared in the same manner as in Comparative Example 5 , except that the binder resin for the charge transport layer was changed to polycarbonate Z (Mw = 75000, manufactured by Mitsubishi Gas Chemical Company) (Example 6). These electrophotographic photosensitive members were used in a copying machine FX27.
The apparatus was installed in a remodeling machine 00 (manufactured by Fuji Xerox Co., Ltd.), and the copying operation was repeated, and the 100th electrophotographic characteristic was measured. Initial charging is 10μ on a single corotron wire.
A current A was applied, and the potential VDDP immediately after charging was measured. The residual potential VRP after irradiation with a fluorescent lamp at a light amount of about 300 erg / cm ² was measured. VDDP, VRP,
Table 4 shows the measurement results of the E1 / 5 value (the value after 100 cycles at 25 ° C. and 40% RH). E1 / 5 indicates the minimum exposure required to reduce the surface potential to 1/5. [Table 4] The compound represented by the general formula (I) used in the present invention has very good compatibility with the binder resin of the photoreceptor layer and has good oxidation resistance. Therefore, the electrophotographic photoreceptor of the present invention is clearly charged, and does not cause light fatigue when used repeatedly. Further, in the present invention, when a polycarbonate resin such as bisphenol Z polycarbonate resin, a polyester carbonate resin, or a polyarylate resin is used as the binder resin in the charge transport layer, the resin has a phenyl ester group in the molecule. In spite of having the compound, the compound represented by the general formula (I) does not have any adverse effect as a charge transport agent. Therefore, such an electrophotographic photosensitive member has excellent electrophotographic properties. In addition, since these binder resins have excellent resistance to solvent erosion, even when layers are formed during photoconductor production, the interface between the layers is not disturbed, and there is no decrease in electrical characteristics due to the disturbed interface between the layers. Furthermore, in the present invention, when the compound represented by the general formula (III) is used, particularly excellent effects are produced. That is, since these compounds have extremely high solubility in a solvent, the amount of the solvent used can be reduced and the viscosity of the solution can be increased. Therefore, the usable width of the electrophotographic photosensitive member can be increased. Electrophotographic photoreceptors using these compounds are also excellent in electrophotographic characteristics.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Naoya Yabuuchi               Fujize, 1600 Takematsu, Minamiashigara, Kanagawa Prefecture               The Rocks Co., Ltd. Takematsu Office (72) Inventor Hiroyuki Tanaka               Fujize, 1600 Takematsu, Minamiashigara, Kanagawa Prefecture               The Rocks Co., Ltd. Takematsu Office                (56) References JP-A-61-132955 (JP, A)                 JP-A-60-17245 (JP, A)                 JP-A-60-52855 (JP, A)                 JP-A-56-135844 (JP, A)                 JP-A-59-71057 (JP, A)                 JP-A-50-151152 (JP, A)

Claims (1)

(57) [Claims] A compound represented by the following general formula (I) and (a) a bisphenol Z carbonate resin on a conductive substrate;
(B) a polyester carbonate resin, (c) a polyarylate resin, (d) a mixture of a bisphenol Z polycarbonate resin and a polyester carbonate resin, and
And (e) an electrophotographic photosensitive member comprising a photosensitive layer containing one selected from a mixture of a bisphenol Z polycarbonate resin and a polyarylate resin. Embedded image (Wherein, R ₁ represents an alkyl group, and R ₂ and R ₃ each represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, an alkoxycarbonyl group, or a substituted amino group). The photosensitive layer comprises a charge generation layer and a charge transport layer, and the charge transport layer comprises a compound represented by the general formula (I) in a binder resin. Electrophotographic photoreceptor. 3. 3. The electrophotographic photoreceptor according to claim 1, wherein the compound represented by the general formula (I) is a compound represented by the following general formula (II). Embedded image (Wherein, R ₄ and R ₅ each represent a hydrogen atom or a methyl group). 4. The electrophotographic photosensitive member according to claim 1, wherein the compound represented by the general formula (I) is a compound represented by the following general formula (III). Embedded image (In the formula, one of R ₆ and R ₇ represents an alkyl group having 2 or more carbon atoms, and the other represents a hydrogen atom, an alkyl group, an alkoxy group, or a substituted amino group.) The electrophotographic photosensitive member according to claim 1 wherein R ₁ in the general formula (I) is characterized in that an alkyl group other than methyl group.