JPS6137621B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composite photoreceptor for electrophotography, in which a photosensitive layer containing a charge transfer material and a charge generation material is provided on a conductive substrate. Specifically, the present invention relates to a photoreceptor characterized in that a 9-10 diether derivative of anthracene is used as an active ingredient of a charge transfer substance. Conventionally, photoreceptors for electrophotography have had good dark chargeability, little dark discharge, fast discharge speed during exposure, low residual potential during exposure, and resistance to deterioration due to repeated use. A variety of characteristics are required, such as the absence of carbon dioxide, and many attempts have been made to meet these requirements. In recent years, organic photoconductors have been researched as photosensitive materials for electrophotography in order to take advantage of their characteristics such as non-polluting properties, processability, flexibility, and lightness, and many patent applications have been filed. For example, U.S. Patent No. 3,484,237 states:
A charge transfer complex of poly-N-vinylcarbazole and 2,4,7-trinitro-9-fluorenone is disclosed in JP-A-52-55643 or JP-A-49-
No. 105536 further describes the use of pyrazoline compounds in combination with chlordian blue or squarylium.
9-(4-diethylaminostyryl)anthracene or N-
Methyl-N-phenylhydrazono-3-methylidene-9-ethylcarbazole in combination with a bisazo compound is described as being useful as an electrophotographic organophotoreceptor. However, these materials do not fully satisfy the above-mentioned required characteristics and have many practical drawbacks. On the other hand, as organic photoconductors, for example, anthracene and anthraquinone have long been used in U.S. patents.
Although it is described in No. 2297691 as one of the photosensitive materials for electrophotography, it was not studied at all as a practical material because its sensitivity was significantly lower than that of amorphous selenium, and it has not been given any attention to this day. In view of the current situation, the inventors of the present invention have conducted extensive research into searching for better organic photoconductors for electrophotography, and have found that certain anthracene-based ether compounds are suitable as charge transport materials for photoreceptors for electrophotography. As a result of further investigation based on this knowledge, the present invention was completed. The main object of the present invention is to provide an electrophotographic photoreceptor that not only has excellent sensitivity but also has a high initial charging voltage and exhibits less deterioration of characteristics even after repeated use. That is, the present invention provides a composite photoreceptor for electrophotography in which a photosensitive layer containing a charge transfer substance and a charge generation substance is provided on a conductive substrate, which has the following general formula: (However, R ₁ and R ₂ are alkyl groups with 1 to 12 carbon atoms,
They are an aryl group and an aralkyl group. R ₁ and R ₂ may be the same or different. Furthermore, n is 0
is an integer of ˜4, and OR ₂ is assumed to be attached to the β position in each case. An electrophotographic photoreceptor characterized in that a compound represented by the following formula is used as an active ingredient of a charge transfer substance. The alkyl group may have either a linear structure or a branched structure. Examples of aralkyl groups include benzyl group, phenylethyl group,
Examples include methylbenzyl group and naphthylmethyl group. Specific examples of the compounds represented by the above general formula used in the present invention are shown in the following structural formulas.

【formula】 【formula】

Note that -C ₆ H ₁₃ in the above formula (7) has a linear structure. These compounds have the corresponding 2,6-dialkoxy-9,10-anthraquinone, 2,6-diaryloxy-9,10-anthraquinone, 2,6-
It can be easily produced by reducing dialkyloxy-9,10-anthraquinone or the like and reacting it with an alkyl halide, an alkyl paratoluenesulfonate, dimethyl sulfate, or the like. An example is as follows. Manufacturing example

Synthesis of [Formula] Add 10.4 g of anthraquinone, 16 g of ethanol, and 5.0 g of zinc powder to a 20% aqueous solution of caustic soda and reflux for 1 hour to reduce the anthraquinone. Subsequently, 28 g of methyl p-toluenesulfonate is added dropwise. The precipitate was filtered, further extracted with benzene, and then recrystallized with toluene to obtain 5 g of the corresponding compound.

Synthesis of [Formula] 2,6-diisopropoxy-9,10-anthraquinone 2g, caustic soda 15g, water 250g, Cortamine (manufactured by Kao Soap Co., Ltd.) 1g, zinc powder 5g
2,6-diisopropoxy-9,10-anthraquinone is reduced by heating at 80°C for 30 minutes in a nitrogen atmosphere. Subsequently, 100 g of toluene was added, and then 20 g of isopropyl iodide was added dropwise under reflux, the precipitate was filtered, and hot extracted with benzene. After evaporation to dryness, the desired product was separated by column chromatography to obtain 0.3 g. The photoreceptor according to the present invention uses a compound as exemplified above as an active ingredient of its charge transfer substance. The details of why these compounds exhibit excellent performance as active ingredients for charge transfer materials are unknown, but since these compounds have low ionization potential, they are suitable for use as charge transfer materials for holes as optical carriers. This is thought to be due to the effective injection. The photoreceptor according to the present invention is configured as follows. One type has a laminated structure, and has a charge generation layer and a charge transfer layer on a conductive substrate, and this charge transfer layer is made of a charge transfer substance containing the above-mentioned compound as an active ingredient. The compound is mixed with a suitable polymeric material to provide film-forming properties. The type of polymer compound used here is not particularly limited, but may include known polymer materials as binders for electrophotography, such as acrylic resins, butyral resins, polyester resins, polycarbonate resins, and silicone resins. etc. can be used as appropriate. These resins may be used alone or in combination of two or more. The appropriate amount of these resins to be used is in the range of 0.1 to 10 parts by weight per 1 part by weight of the compound of the present invention. In the case of a laminated structure, the thickness of the charge generation layer is suitably about 0.03 to 3 μm, and this can be done by vapor depositing the charge generation substance or by coating it by dispersing it in a suitable binder. The thickness of the charge transfer layer is 5
~50μ is appropriate. Another structure is formed by mixing a charge transfer substance and a charge generation substance and mixing them with the above-mentioned polymeric material to form a film. It is appropriate that these proportions be such that the charge generation material accounts for 10 to 30% by weight of the charge transfer material. As the conductive substrate of the electrophotographic plate of the present invention, conductive substrates used in electrophotographic photoreceptors such as aluminum sheets, paper or plastic sheets coated with aluminum powder, and aluminum vapor-deposited plastic films can be used. Further, as the charge generating substance, conventionally known organic pigments, dyes, charge transfer complexes, etc. can be used as appropriate. For example, azo pigments such as organic monoazo, disazo, and trisazo pigments, azo lake pigments, phthalocyanines such as Al, Cu, Mg, Pb, and Zn, phthalocyanine pigments such as halogenated copper phthalocyanine, and halogenated aluminum phthalocyanine, thioindigo pigments, Organic pigments such as anthraquinone-based, perinone-based, perylene-based pigments, dioxazine-based, quinacridone-based, isoisodorinone-based, fluorobin-based, pyrocholine-based pigments, triphenylmethane-based pigments, metal complex pigments, amorphous silicon (Si), Selenium (Se), tellurium (Te), cadmium sulfoselenide (CdSSe), arsenic selenide (As ₂ Se ₃ ), antimony sulfide (Sb ₂ S ₃ ), antimony selenide (Sb ₂ Se ₃ ),
Cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe), zinc oxide (ZnO), zinc sulfide (ZnS) and these two
Inorganic pigments such as mixtures or alloys of more than one species, acidic azo dyes such as monoazo and disazo, o-hydroxycarboxylic acid type, peridihydroxy type, ortho-
Acid mordant azo dyes such as oxyazo type, direct azo dyes such as benzidine type, diaminodiphenylamine type, stilbene type, J acid type, continuous azo type, thiazole type, urea type, cyanuric acid type, chromium complex type, neolan type , metal complex dyes such as palatin fast type, benzofasto chrome type, and copper complex salt type, chlorinated azo dyes, azoic dyes, anthraquinone mordant dyes such as alizarin type, trioxyanthraquinone type, and polyoxyanthraquinone type, and anthraquinone type acidic dyes. Dyes, indanthrone series, flavanthrone series, pyranthrone series, amyl aminoanthraquinone series, anthrimide series, anthraquinone carbazole series, acridone series, thioxanthone series, benzantrone series, dibenzpyrenequinone series, anzanthrone series, pyrazole anthrone series, pyrimidoanthrone series Anthraquinone vat dyes such as thiazole series, thiophene series, imidazole series, phthalic carboxylic acid series, many quinone series, indigoid dyes such as indochol indigo series and thioindigo series, and soluble dyes such as anthrazole series and sorendon series. Carbonium dyes such as vat dyes, sulfur dyes, diphenylmethane series, triphenylmethane series, xanthene series, phthalein series, acridine series, quinoneimine dyes such as azine series, oxazine series, and thiazine series, phthalocyanine dyes, cyanine dyes, quinoline dyes, There are various dyes such as nitro dyes, nitroso dyes, naphthoquinone dyes, procion dyes, and fluorescent dyes, and at least one of these is used. In addition, if necessary, a barrier layer such as polyvinyl alcohol or polyamide can be provided on the conductive substrate, or a barrier layer such as polycarbonate resin, silicone resin, or nitrified cotton can be applied to the surface of the photoreceptor to improve printing durability. A protective film such as this can also be provided. Next, the present invention will be explained in detail with reference to examples. Example 1 A solution prepared by dispersing chlorinated Diane blue in ethylenediamine at a concentration of 2 wt% was applied onto a polyester film (manufactured by Toray Industries, Metal Me, film thickness: 50 μm) on which aluminum was vapor-deposited, and dried to generate a charge with a thickness of 1 μm. Created a film of material.
Polycarbonate resin (Iupilon S2000 manufactured by Mitsubishi Gas Chemical Co., Ltd.) is coated with a compound represented by structural formula (1) on top of this.
in a weight ratio of 2:3, and dissolved in tetrachloroethane as a solvent to give a concentration of 10% by weight.The solution was applied with an applicator and dried, until the thickness
A coating film of 10μ was obtained. The electrophotographic photoreceptor produced in this way was tested using an electrostatic recording paper tester (manufactured by Kawaguchi Electric).
SP-428) was used to evaluate its properties. As a result, the initial charging voltage is 400V, and the irradiation half-reduction exposure sensitivity at 500Lux of the charged photoreceptor is
It was 45Lux・sec. Characteristics were repeatedly evaluated using this device, and no deterioration in characteristics was observed even after ¹⁰³ repetitions. Example 2 A photoreceptor was prepared in the same manner as in Example 1, except that the compound represented by structural formula (4) was used, and its characteristics were evaluated.
The cut-off voltage is 500V, and the half-reduction exposure sensitivity is
18 Lux·sec, and no deterioration in characteristics was observed even after repeated tests of 10 ³ or more times. Example 3 Copper phthalocyanine (Lionol ES manufactured by Toyo Ink) was deposited on an aluminum plate with a thickness of 100 μm to a thickness of 0.1 μm, and the compound of structural formula (5) was added to a polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) at a ratio of 1:1. They were mixed in a weight ratio to form a 20% by weight solution of tetrahydrofuran, which was coated and dried to form a dry film of 10 μm. Sensitivity was measured in the same manner as in Example 1, but the initial charging voltage
The voltage was 800V, the sensitivity was 8Lux・sec, and it was able to withstand 1000 repeated tests. Example 4 Perimide pigment (PALIOGEN Maroon L4020 manufactured by BASF) was applied to a thickness of 100 μm on an aluminum plate.
It was deposited to a thickness of 500 Å. On top of this, acrylic resin (DuPont Elbasite 2045) and structural formula
Compound (6) was blended at a weight ratio of 1:1, and 10% by weight was added to a mixed solvent of dichloroethane/benzene = 1/1.
Dissolved, applied and dried to form a dry coating film of 10μ
I made it so that The characteristics of the obtained photoreceptor are shown below. Sensitivity 8Lux・sec Repeated 1000 times No abnormality Initial charging voltage 900V Example 5 Copper phthalocyanine (Toyo Ink Onol)
ES) 1 part by weight, 25% of compounds (5), (6), (7), (8), (9)
Weight part, polyester resin (Toyobo Vylon)
200) 25 parts by weight, tetrahydrofuran 100
After thoroughly dissolving and mixing, the mixture was coated on a 100 μm thick aluminum plate at room temperature to obtain a 20 μm thick dry film. The characteristics of the obtained photoreceptor were as follows.

【table】

Claims (1)

[Claims] 1. An electrophotographic composite photoreceptor comprising a conductive substrate and a photosensitive layer containing a charge transfer substance and a charge generation substance, which has the following general formula: (However, R ₁ and R ₂ are alkyl groups with 1 to 12 carbon atoms,
They are an aryl group and an aralkyl group. R ₁ and R ₂ may be the same or different. Furthermore, n is 0
is an integer of ˜4, and OR ₂ is assumed to be attached to the β position in each case. ) A photoreceptor for electrophotography, characterized in that a compound represented by the following formula is used as an active ingredient of a charge transfer substance.