JPH0544026B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing an electrophotographic light-sensitive material used in an electrophotographic process. More specifically, the present invention relates to a method for producing a squareryllium compound used as a photoconductive material. [Prior Art] Conventionally, inorganic photosensitive materials such as amorphous selenium, selenium alloys, cadmium sulfide, and zinc oxide, and organic photosensitive materials such as polyvinyl carbazole and polyvinyl carbazole derivatives have been widely known as photosensitive materials for electrophotography. It is being It is well known that amorphous selenium or selenium alloys have extremely excellent properties as electrophotographic light-sensitive materials and are used in practical applications. However, its production requires a complicated step of vapor deposition, and the produced vapor-deposited film has the drawback of not being flexible. When zinc oxide is used, it is used as a dispersed photosensitive material in which zinc oxide is dispersed in a resin, but such a photosensitive material has a drawback in mechanical strength and cannot withstand repeated use as it is. Polyvinylcarbazole, which is widely known as an organic photoconductive material, has excellent advantages in terms of transparency, film-forming properties, and flexibility, but polyvinylcarbazole itself has no sensitivity in the visible light range, so it cannot be used as is. Therefore, various sensitization methods have been devised.
However, when polyvinylcarbazole is spectrally sensitized using a dye sensitizer, the spectral sensitivity range is extended to the visible light range, but it still cannot achieve sufficient sensitivity as a photoreceptor for electrophotography and suffers from severe photofatigue. It has the disadvantage of being In addition, when chemically sensitized using an electron-accepting compound, a photoreceptor with sufficient sensitivity as an electrophotographic photoreceptor can be obtained, and some of them have been put into practical use, but mechanical strength still remains. However, there are still problems in terms of lifespan, etc. In recent years, many types of organic photoreceptors have been studied, and in particular, it has been reported that a laminated type photoreceptor having a charge generation layer and a charge transport layer has superior electrical properties compared to conventional photoreceptors. Known charge-generating materials used in these photoreceptors include bisazos, trisazos, phthalocyanines, pyryliums, and squareryliums, and phthalocyanines are sensitive from the visible region to the near-infrared region. Tris-azo-classes, trisazo-classes, and squarerillium-classes have been reported. However, phthalocyanines have the disadvantage that their spectral sensitivity is biased toward long wavelengths and red color reproducibility is poor, and trisazo compounds have not yet achieved excellent electrical properties and sufficient sensitivity. Furthermore, although the squarylium compounds disclosed in JP-A-49-105536 and the like have relatively high sensitivity, they have drawbacks such as chargeability and dark decay, and have not been able to achieve both high sensitivity and low dark decay. [Problems to be Solved by the Invention] The purpose of the present invention is to solve the above-mentioned drawbacks, and to provide an electrophotographic device that has spectral sensitivity from the visible region to the near-infrared region, and has high sensitivity and excellent electrical properties. An object of the present invention is to provide a method for producing a photosensitive material. [Means and effects for solving the problems] The objects of the present invention can be achieved by a method for producing an electrophotographic light-sensitive material comprising an asymmetric squarerylium compound represented by the following general formula (). In the general formula (), R ₁ and R ₂ are independent of each other and represent a hydrogen atom, a hydroxyl group, a methyl group, a halogen atom, a trifluoromethyl group, or a carboxyl group, and X is a formula

[expression] or

〔Example〕

Synthesis example 3,4-dichloro-3-cyclobutene-1,2
- 3.00 g of dione and 2.65 g of aluminum chloride were stirred in 30 ml of methylene chloride while keeping the temperature below 5°C until the aluminum chloride was dissolved. To this, add 2.43 g of N,N-dimethylaniline to 30
The solution was added dropwise for 2.5 hours, and the reaction was continued for 2.5 hours while maintaining the solution temperature at 5° C. or lower. After the reaction, IM-HCl,
Washed with water and then separated by column chromatography to produce 1.64 g of product (yield:
35%). Next, add 1.56 g of the compound () to 30 ml of glacial acetic acid and 6 ml of water.
ml of mixed solvent, heated under reflux for 2 hours, cooled to room temperature, and separated the precipitated crystals to obtain 1.376 g (yield: 95.7%) of product (2). Next, 1.00 g of product (X) and 3-fluoro-N,
After heating and refluxing 1.92 g of N-dimethylaniline in 90 ml of butanol for 20 hours, the reaction solution was cooled to room temperature, the precipitated crystals were separated, washed with methanol and ether, and dried to obtain the product (Example No.
1) 1.01g (yield 64.8%) was obtained. Decomposition point: 276℃ Elemental analysis: Calculated values C70.99%, H5.66%, N8.28% Actual values C71.05%, H5.74%, N8.29%. Example 1 To 1 part by weight of the compound represented by the structural formula of Specific Example No. 1, 1 part by weight of polyester resin (manufactured by Dupont, Adhesive 49000) and 10 parts by weight of tetrahydrofuran were added, and the mixture was ground and mixed in a ball mill for 4 hours to obtain a dispersion. was applied onto a polyester film (Metal Me (registered trademark) manufactured by Toray Industries, Ltd.) on which aluminum had been vapor-deposited using a barcoder, and dried at 70° C. for 5 hours to form a charge generation layer with a thickness of 1 μm. On this charge generation layer, N,N'-diphenyl-
N,N'-bis-(3-methylphenyl)-(1,
1 part by weight of 1'-biphenyl)-4,4'-diamine,
A homogeneous solution consisting of 1 part by weight of polycarbonate resin (manufactured by Teijin, Panlite (registered trademark)) and 10 parts by weight of tetrahydrofuran was applied using an applicator and dried at 70°C for 16 hours to form a charge transport layer with a thickness of 22μ. Next, an electrostatic copying paper testing device (manufactured by Kawaguchi Electric, Electrostatic Paper Analyzer SP) was used.
-428) to negatively charge the photosensitive layer with -6KV corona discharge, leave it in the dark for 2 seconds, and then use a tungsten lamp to irradiate the photosensitive layer with light so that the surface illuminance is 10 lux. The exposure amount E1/2 was determined so that the surface potential was 1/2 of the surface potential V _D after being left in the dark. The result is that the initial charging potential V ₀ =
-870V, potential after being left in the dark for 2 seconds V _DDP = -
750V, E1/2 = 2.0 Lux・sec, residual potential R _p =
It was -5V. In addition, the following measurements were performed to demonstrate that the material has extremely high sensitivity to long wavelength light. After charging the above photoreceptor by corona discharge in a dark place, use a monochromator to charge it at 800nm.
The photoreceptor was irradiated with monochromatic light of 1 μW/cm ² which was divided into 1 μW/cm 2 . The amount of exposure was determined by measuring the time until the surface potential decreased to 1/2. The result was 10.9ergcm ^-2 . Examples 2 to 10 In Example 1, instead of the squarerium pigment of Specific Example No. 1, No. 4, 5, 6, 10, 12, and
Photoreceptors were prepared and evaluated in the same manner as in Example 1, except that the squarerium pigments Nos. 13, 15, 23, and 27 (Examples 2 to 10, respectively) were used. Table 1 shows the results of evaluation.

〔Effect of the invention〕

The present invention provides a method for producing an electrophotographic photosensitive material made of an asymmetric squareryllium compound that has spectral sensitivity from the visible region to the near-infrared region, and has high sensitivity and excellent electrical properties. In an electrophotographic photoreceptor including a photosensitive layer with a two-layer structure consisting of a generation layer 2 and a charge transport layer 3, by providing a charge generation layer containing the squareylium compound according to the present invention and a known charge transport layer 3. , it is possible to produce a photoreceptor with high sensitivity and improved electrical properties such as chargeability and dark decay. Electrophotographic photoreceptors using these asymmetric squarerium pigments can be widely used not only in copying machines but also in semiconductor laser printers and the like.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of examples of the electrophotographic photoreceptor of the present invention. Symbols in the figure: 1... conductive support, 2... charge generation layer, 3... charge transport layer, 4... photosensitive layer.

Claims (1)

[Claims] 1 Formula () 3,4-dichloro-3-cyclobutene-1,2-dione represented by the general formula () (In the formula, R ₁ is a hydrogen atom, a hydroxyl group, a methyl group,
Represents a halogen atom, trifluoromethyl group or carboxyl group. ) is reacted with the aniline derivative represented by the general formula (). (In the formula, R ₁ represents the same meaning as above.) A compound represented by the formula () is obtained, and then the compound of the formula () is hydrolyzed to obtain the compound of the general formula () (In the formula, R ₁ represents the same meaning as above.) A compound represented by the general formula () is obtained, and a compound of the general formula () is [In the formula, R ₂ is a hydrogen atom, a hydroxyl group, a methyl group,
Represents a halogen atom, trifluoromethyl group, or carboxyl group, and X represents the formula [Formula] or [Formula] (wherein R ₃ and R ₄ are mutually independent, and are an alkyl group having 1 to 20 carbon atoms. and Z represents a group of atoms necessary to form a ring. ] General formula () characterized by reacting with a compound represented by (In the formula, R ₁ , R ₂ and X have the same meanings as above.) A method for producing an electrophotographic light-sensitive material comprising an asymmetric squarerylium compound. 2 formula () 3,4,-dichloro-3-cyclobutene-1,2-dione represented by the general formula () [In the formula, R ₂ is a hydrogen atom, a hydroxyl group, a methyl group,
Represents a halogen atom, trifluoromethyl group, or carboxyl group, and X represents the formula [Formula] or [Formula] (wherein R ₃ and R ₄ are mutually independent, and represent an alkyl group having 1 to 20 carbon atoms. and Z represents a group of atoms necessary to form a ring. ] By reacting with a compound represented by the general formula () (In the formula, R ₂ and (In the formula, R ₂ and X have the same meanings as above.) (In the formula, R ₁ is a hydrogen atom, a hydroxyl group, a methyl group,
Represents a halogen atom, trifluoromethyl group or carboxyl group. ) General formula () characterized by reacting with an aniline derivative represented by (In the formula, R ₁ , R ₂ and X have the same meanings as above.) A method for producing an electrophotographic photoreceptor material comprising an asymmetric squarerylium compound.