JPS6255658B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electrophotographic plate that is effective for creating images by electrophotography, and particularly to an electrophotographic plate that has high sensitivity even to long-wavelength light and is composed of a charge-generating material and a charge-transporting material. BACKGROUND ART In recent years, as a type of high-speed printer, a method of printing using an electrophotographic method using a laser as a light source has been used. Among laser beams, when a semiconductor laser is used as a light source, the light source section is very small, so printers can be made smaller and power consumption can be significantly reduced, which is why this is attracting particular attention. However, the oscillation wavelength of a semiconductor laser is usually an extremely long wavelength of 800 nm or more. Therefore, there has been a strong desire to develop an electrophotographic plate that is highly sensitive to wavelengths of 800 nm or more. By the way, conventional electrophotographic plates are mainly for copying machines that use visible light as the light source;
It has high sensitivity to wavelengths of 600 nm or less, but has virtually no sensitivity to wavelengths above that, or even if it does have sensitivity, it is too low to be of practical use. The purpose of the present invention is to eliminate the drawbacks of conventional electrophotographic plates, have high sensitivity in an extremely wide wavelength range (500 to 825 nm, especially 650 to 800 nm), and have durability and
The object of the present invention is to provide an electrophotographic plate that has excellent repeatability, is rigid or flexible, and is suitable for use on a wide variety of substrates of many different shapes. The electrophotographic plate of the present invention is an electrophotographic plate comprising a photoreceptor layer containing a charge generating substance and a charge transporting substance on a conductive support, in which the charge transporting substance is (a) nitrofluorenone and its derivatives. At least one selected nitrofluorenone compound and (b) the following general formulas () and () [In formulas () and (), Rx, Ry and Rz
is hydrogen, hydroxyl group, halogen atom, lower alkyl group, lower alkoxy group, nitro group, amino group, mono-lower alkylamino group, di-lower alkylamino group, acylamide group, sulfonylamide group, monoaralkylamino group, dialkylamino group and an aryl group, which may be the same or different. It is characterized by using at least one type of leucolactone compound shown in the following. According to the present invention, it is possible to obtain an electrophotographic plate that has a wide photosensitive wavelength range and exhibits the highest sensitivity particularly to long wavelengths (600 to 825 nm). Although it is not clear why the electrophotographic plate of the present invention exhibits the above-mentioned sensitivity characteristics, it exhibits high sensitivity when positively charged, which indicates that electrons are injected from the charge-generating material into the charge-transporting material when irradiated with light. It is assumed that this is because it is carried out efficiently. Examples of the nitrofluorenone compound that is a component of the charge transport substance used in the present invention include 2,4,7-trinitrofluorenone, 2,4-
or 2,7-dinitrofluorenone, 2- or 4-nitrofluorenone, 2,4,5,7-
Examples include tetranitrofluorenone and substituted products thereof with cyano group, halogen, alkoxy group, alkyl group, and aralkyl group, and at least one of these is used. In addition, examples of leucolactone compounds that are other constituents include the following formulas (1) to
(33), There are the following, and at least one of these is used. The blending ratio of the nitrofluorenone compound and the leucolactone compound can be selected over a wide range. Generally, the latter is used in a range of 0.1 to 10 moles per 1 mole of the former, most preferably 0.5 to 2 moles. If the ratio of the latter to the former is extremely excessive, the charging characteristics necessary for an electrophotographic plate will deteriorate, particularly resulting in a decrease in charging voltage and an increase in dark charge attenuation. Also,
In the opposite case, the proportion of charge that remains even after light irradiation increases, resulting in a decrease in photosensitivity and a risk of property deterioration due to repeated use. The nitrofluorenone compound and leucolactone compound mentioned above are used as the charge transporting substance, but when forming a layer, more preferable results can be obtained by using a binder. In this case, the amount of binder to be used is generally in the range of 30 to 90% by weight based on the weight of the entire layer of charge transport material. Desirably, it is in the range of 45 to 75% by weight. The use of binders improves mechanical properties, in particular abrasion resistance, flexibility and weather resistance. Examples of binders include linear saturated polyester resin, polycarbonate resin, acrylic resin,
Butyral resin, polyketone resin, polyurethane resin, poly-N-vinylcarbazole, poly-(p-vinylphenyl)anthracene, and the like are used. The thickness of the charge transport material layer should be appropriately determined depending on the charging characteristics required for the electrophotographic plate. In general, a suitable thickness is 5 to 100 μm, preferably 8 to 30 μm. In the present invention, all known charge generating substances are effective. Examples include azo pigments such as monoazo, disazo, and trisazo pigments, azo lake pigments, metal phthalocyanine pigments such as Cu, Mg, Pb, and Zn phthalocyanines, and halogenated copper phthalocyanines, or metal-free phthalocyanine pigments, thioindigo pigments, and anthraquinone pigments. Organic pigments such as perinone, perylene, dioxazine, quinacridone, isoindolinone, fluorobin, pyrocholine, triphenylmethane, or metal complex pigments, silicon, selenium, tellurium, 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, zinc sulfide and their two
Examples include mixtures of two or more kinds of metals, and alloys of two or more kinds of the above metals. Preferred are copper phthalocyanine and disazo pigments, and combinations thereof are particularly effective. Other types include acidic azo dyes such as monoazo and disazo, acidic mordant azo dyes such as O-hydroxycarboxylic acid type, peridihydroxy type, and ortho-oxyazo type, benzine type, diaminodiphenylamine type, stilbene type, and J acid type. , direct azo dyes such as continuous azo type, thiazole type, urea type, siataric acid type, metal complex salt dyes such as chromium complex type, neolan type, palatine fast type, benzofasto chromium type, copper complex type, basic azo Dyes, azoic dyes, anthraquinone mordant dyes such as alizarin, trioxyanthraquinone, and polyoxyanthraquinone, anthraquinone acid dyes, indanthrone, flavanthrone,
Pyrantrone series, amyl aminoanthraquinone series, anthrimide series, anthraquinone carbazole series, acridone series, thioxanthone series, benzantrone series, dibenzpyrenequinone series, anzanthrone series, pyrazole anthrone series, pyrimidoanthrone series, thiazole series, thiophene series, imidazole series , phthalic carboxylic acid, many anthraquinone vat dyes such as quinone, indigoid dyes such as indochol indigo and thioindigo, soluble vat dyes such as anthrazole and soledone, sulfur dyes, diphenylmethane,
Carbonium dyes such as triphenylmethane, xanthene, phthalein, and acridine; quinone imine dyes such as azine, oxazine, and thiazine; phthalocyanine dyes; cyanine dyes; quinoline dyes; nitro dyes; nitroso dyes;
naphthoquinone dye, procion dye, fluorescent dye,
Various dyes are also useful. The particle size of the charge generating material can be selected over a fairly wide range. In general, it can be said that the finer the details, the more advantageous they are. The preferred particle size is 5 μm or less,
In particular, it is 1 μm or less. The same binder as described above can be used in the layer of charge generating material, if necessary. The amount used is generally from 50 to 98% by weight based on the entire layer of charge generating material. In the present invention, aluminum, brass, copper, gold, etc. are used as the conductive support. The conductive support layer itself may have the function of supporting the photoconductor layer. For example, a plate or cylinder made of the above-mentioned metal or a plate or cylinder coated with the above-mentioned metal can be used as a conductor layer, and the above-mentioned photoconductor layer can be formed on the surface thereof, and the plate or cylinder can be used as an electrophotographic plate. Further, the conductive layer may be formed on a supporting base material such as a plastic film or paper. This type is particularly suitable for obtaining long electrophotographic plates. Furthermore, the conductor layer may be formed by forming a thin layer of aluminum iodide, copper iodide, chromium oxide, or tin oxide on a glass body, such as a plate-shaped or cylindrical glass body. Next, examples of the present invention will be shown. Example 1 1 part by weight of β-type copper phthalocyanine (manufactured by BASF, Heliogen Blue 7080) which is a charge generating substance, 1 part by weight of a disazo pigment (manufactured by Dainippon Ink Co., Ltd., Sumirar First Blue 4135) and butyral resin (Union Car). Add 1 part by weight of XYHL (manufactured by Baito Co., Ltd.) to xylene and knead in a ball mill for 5 hours to prepare a charge generating substance coating liquid with a non-volatile content of 6% by weight. It was applied using a tick applicator (manufactured by Toyo Seiki Co., Ltd.) and dried to form a layer of charge-generating material. The thickness of this layer is approximately 3 μm. Next, as charge transport substances, 0.10 g of 2,4,7-trinitrofluorenone (manufactured by Tokyo Kasei Kogyo Co., Ltd.), 0.10 g of a leucolactone compound (crystal violet lactone) represented by the previous formula (4), and polycarbonate resin (Mitsubishi A coating liquid of a charge transport substance was prepared by mixing 0.32 g of Iupilon S-2000 (manufactured by Gas Kagaku Co., Ltd.), 3 ml of dichloromethane, and 1 ml of 1,2-dichloroethane.
In preparation, the resin component was completely dissolved, and then the charge transport substance was added. This method is effective in obtaining a homogeneous coating. This coating solution was applied onto the layer of charge transport material using an automatic applicator. The thickness of the layer of charge transport material formed is approximately 10μ
It is m. The electrophotographic properties of the thus obtained composite electrophotographic plate were evaluated using an electrostatic recording tester (manufactured by Kawaguchi Electric Co., Ltd., SP-428). First, white light sensitivity is determined by charging with a positive 5 kV corona discharge for 10 seconds (the initial potential is the surface potential V ₀ (V) immediately after charging for 10 seconds), and after leaving it in the dark for 30 seconds (the surface potential during this time is is expressed in V ₃₀ (V), and V ₃₀ /V ₀ × 100% is the dark decay.), the surface potential is exposed to light using a tungsten lamp so that the illumination intensity is 20 lux, and the decay of the surface potential and time are Record the time t (seconds) until V ₃₀ becomes 1/2
The white light sensitivity (half exposure amount) and E ₅₀ (lux (seconds)) were measured by calculating the product of and illuminance. Also,
Spectral sensitivity is determined by irradiating a spectrum of each wavelength through a spectroscope with a tungsten lamp, and calculating the reciprocal of the product of the time t (seconds) until V ₃₀ becomes 1/2 and the energy (μW/cm ² ) of each spectrum. , spectral sensitivity (cm ² /
erg) was measured. As a result, the characteristics of the electrophotographic plate of this example are: initial potential of approximately 600 V, dark decay of 40%, and white light sensitivity.
It showed an extremely excellent value of 5.0 lux·sec.
Further, the spectral sensitivity shows a maximum in the range of 600 to 800 nm, and the peak value exceeds 0.05 cm ² /erg. Note that the residual voltage was 0V. Next, this electrophotographic plate was charged with a positive 5kV for 10 seconds in a dark place, followed by close exposure using a semiconductor laser with an output of 5mW and a wavelength of 800nm, and developed using the cascade method. A visual image was obtained. Example 2 3 parts by weight of ε-type copper phthalocyanine (Lion Noble-ESP, manufactured by Toyo Ink Co., Ltd.) and 1 part by weight of a disazo pigment having the following structure were used as charge-generating substances. Add diethylamine to the solution to increase the charge generating substance concentration to 7.
Expressed as weight%. After the charge generating substance was sufficiently dispersed in this liquid using ultrasonic waves, a layer of the charge generating substance was obtained by the same operation as in Example 1. The thickness of this layer is approximately 2 μm. Next, as a layer of charge transport material, 2,4,7-
Trinitrofluorenone (TNF) and the previous formula (24)
A layer of a charge transport substance was formed on a layer of a charge generation substance by the same operation as in Example 1, except that the ratio of 3-dimethylamino-7-dibenzylaminofluorane, which is a leucolactone compound represented by , was changed. . The film thickness is 10 μm. The properties of the obtained electrophotographic plate are shown in the table below.

[Table] After further charging in the dark at a positive 5kV for 10 seconds, contact exposure was performed using a semiconductor laser with an output of 5mW and a wavelength of 800nm, and development was performed using the cascade method, resulting in a clear visible image. Example 3 Diethylamine was added to 1.5 parts by weight of β-type copper phthalocyanine (Cyanine Blue LC, manufactured by Dainippon Ink Co., Ltd.) and 0.5 parts by weight of the same disazo pigment as in Example 2, so that the concentration of the charge generating substance was 7% by weight. This liquid was subjected to the same operation as in Example 2 to form a layer of charge generating material. Next, as a charge transport material, 2, 4, 7
- 0.15 g of trinitrofluorenone and 0.05 g of malachite green lactone represented by the above formula (2) were added, and a layer of charge transport material was formed in the same manner as in Example 1 to obtain a composite electrophotographic plate. Characteristics are initial potential 500V, dark decay 50%, white light sensitivity 4
lux/second (no residual potential). Furthermore, as in Example 1, an image forming test was conducted using a semiconductor laser light source, and as a result, clear images were obtained. Example 4 A charge-generating material layer (thickness: 3 μm) was obtained in the same manner as in Example 3. Next, as a charge transport material, 2,
0.10 g of 7-acetamino-3-diethylaminofluorane shown in the previous formula (33) was added to 0.20 g of 4,7-trinitrofluorenone, and then a saturated polyester resin (Toyobo K, Vylon-200 manufactured by K) was added.
A charge transport material layer (15
(μm thickness) was formed. The resulting electrophotographic plate had an initial potential of 400 V, dark decay of 30%, and white light sensitivity of 3.6.
It exhibited extremely excellent characteristics, with a lux.second (no residual potential). Furthermore, as in Example 1, an image forming test was conducted using a semiconductor laser light source, and as a result, clear images were obtained. The electrophotographic plates of the above examples also have excellent repeatability and durability.

Claims (1)

[Scope of Claims] 1. An electrophotographic plate comprising a photoreceptor layer containing a charge generating substance and a charge transporting substance on a conductive support, wherein the charge transporting substance is selected from (a) nitrofluorenone and its derivatives. and (b) the following general formulas () and (): [In formulas () and (), Rx, Ry and Rz
is hydrogen, hydroxyl group, halogen atom, lower alkyl group, lower alkoxy group, nitro group, amino group, mono-lower alkylamino group, di-lower alkylamino group, acylamide group, sulfonylamide group, monoaralkylamino group, dialkylamino group and an aryl group, which may be the same or different. An electrophotographic plate comprising at least one leucolactone compound represented by the following. 2 The nitrofluorenone compound is 2,4,7
- The electrophotographic plate according to claim 1, characterized in that it is trinitrofluorenone. 3. The electrophotographic plate according to claim 1 or 2, wherein the charge generating substance contains at least one of copper phthalocyanine and a disazo pigment. 4. The composition according to claim 1, 2 or 3, wherein the composition ratio of the nitrofluorenone compound and the leucolactone compound is 0.1 to 10 mol of the latter to 1 mol of the former. Electrophotographic plate. 5. The charge generating material and the charge transporting material are laminated as separate layers on the conductive support, according to claim 1, 2, 3, or 4. electronic photographic plate. 6. The electronic device according to claim 5, wherein the layer of the charge-generating substance is formed on the conductive support side, and the layer of the charge-generating substance is formed on the surface of the layer of the charge-generating substance. photo plate. 7. An electrophotographic plate comprising a photoreceptor layer containing a charge generating substance and a charge transporting substance on a conductive support, wherein the charge transporting substance is (a) a nitrofluorenone compound selected from nitrofluorenone and its derivatives. At least one species and (b) the following general formulas () and () [In formulas () and (), Rx, Ry and Rz
is hydrogen, hydroxyl group, halogen atom, lower alkyl group, lower alkoxy group, nitro group, amino group, mono-lower alkylamino group, di-lower alkylamino group, acylamide group, sulfonylamide group, monoaralkylamino group, dialkylamino group and an aryl group, which may be the same or different. An electrophotographic plate comprising at least one leucolactone compound represented by the following formula and (C) a binder. 8 The nitrofluorenone compound is 2,4,7
- The electrophotographic plate according to claim 7, characterized in that it is trinitrofluorenone. 9. The electrophotographic plate according to claim 7 or 8, wherein the charge generating substance contains at least one of copper phthalocyanine and a disazo pigment. 10. Electrophotography according to claim 7, 8 or 9, characterized in that the composition ratio of the nitrofluorenone compound and the leucolactone compound is 0.1 to 10 mol of the latter to 1 mol of the former. plate. 11. Claims 7 and 8, characterized in that the charge generating material and the charge transporting material are laminated as separate layers on the conductive support.
The electrophotographic plate according to item 9 or 10. 12. Electrophotography according to claim 11, characterized in that the layer of the charge generating substance is formed on the side of the conductive support, and the layer of the charge generating substance is formed on the surface of the layer of the charge generating substance. plate.