JPH024624B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel trisazo compound and a method for producing the same. It has been known that trisazo compounds or disazo compounds are effective as charge-generating pigments used in charge-generating layers of laminated photoreceptors, which are one form of photoreceptor used in electrophotography. The laminated photoreceptor referred to herein means that a charge-generating pigment having the ability to generate charge carriers by light is deposited on a conductive support by an appropriate method, such as vacuum deposition, coating with a pigment solution, or coating with a resin solution.
A charge generation layer is formed as a thin layer by coating a dispersion liquid containing fine particles of pigment, and the charge carriers generated in the charge generation layer can be efficiently injected onto the layer and the charge carriers can be transferred. It is a photoreceptor on which a charge transfer layer (usually, this charge transfer layer consists of a charge transfer substance and a binder resin) is formed.
Conventionally, as disazo compounds used in this type of photoreceptor, benzidine-based disazo pigments disclosed in JP-A-47-37543 or JP-A-52-55643, or JP-A-53
Torphenylamine-based trisazo pigments disclosed in Japanese Patent No. 132547 are well known. However, conventional laminated photoreceptors using trisazo pigments or disazo pigments have lower sensitivity when compared to inorganic photoreceptors using, for example, arsenic selenium (As ₂ Se ₃ ) alloys, making them difficult to use in high-speed copying machines. It has drawbacks such as not being suitable as a photoreceptor. Furthermore, the demand for photoreceptors for laser printers has increased in recent years, and there is an urgent need to develop photoreceptors with high sensitivity, especially in the wavelength range of semiconductor lasers. The purpose of the present invention is to provide a novel trisazo compound that is effective in the above-mentioned laminated photoreceptor, and the laminated photoreceptor using the trisazo compound of the present invention is superior to inorganic photoreceptors. It was found that the sensitivity was comparable in terms of sensitivity, and the response was extremely fast up to light with a wavelength of 800 nm. Another object of the present invention is to provide a method for producing the above trisazo compound. In other words, one of the aspects of the present invention is the formula () It is a trisazo compound represented by This new trisazo compound is a black crystalline substance at room temperature. Figure 1 shows the infrared absorption spectrum (KBr tablet method) of [], and Figure 2 shows the thermal analysis diagram (TG-
DSC) and an X-ray diffraction diagram is shown in Figure 3. The above trisazo compound of the present invention can be produced by the following method. That is, another aspect of the present invention is the formula () By diazotizing 4,4',4''-triaminotriphenylamine represented by the general formula () (However, X represents an anionic functional group.) As a hexazonium salt represented by the following, this hexazonium salt and the formula () The above formula () characterized by reacting with 2-hydroxy-3-(4-methylphenylcarbamoyl)benzo[a]carbazole represented by
This is a method for producing a trisazo compound represented by In this production method, 4,4',4''-triaminotriphenylamine is diazotized by heating an aqueous sodium nitrite solution to -10°C to 10°C in a dilute inorganic acid such as dilute hydrochloric acid or dilute sulfuric acid. This diazotization reaction is completed in about 30 minutes to 3 hours. Furthermore, hydroboric acid or an aqueous sodium borofluoride solution is added to the reaction mixture to precipitate a hexazonium salt, and crystallize. It is preferable to use the hexazonium salt in the next reaction after removing it.Next, the 2-hydroxy-3-(4
-methylphenylcarbamoyl)benzo[a]carbazole to cause a coupling reaction. In reality, this reaction is carried out by mixing and dissolving a hexazonium salt and a coupler in an organic solvent such as N,N-dimethylformamide (DMF) or dimethyl sulfoxide.
This is carried out by dropping an alkaline aqueous solution such as an aqueous sodium acetate solution at about -10°C to 40°C. This reaction is complete in approximately 5 minutes to 3 hours. After the reaction is complete, collect the precipitated crystals and purify them by an appropriate method (e.g. washing with water and/or organic solvent, recrystallization method, etc.)
By doing so, the production of the above trisazo compound is completed. Examples of the production of the trisazo compound of the present invention produced in this manner are as follows. Production example 4,4′,4″-triaminotriphenylamine
Add 8.7gr to diluted hydrochloric acid prepared from 150ml and 130ml of concentrated hydrochloric acid, and stir well at room temperature for about 30 minutes. The mixture was then cooled to about 0°C and sodium nitrite
A solution of 7.7gr dissolved in 30ml of water was added dropwise at a temperature of -3°C to 2°C over about 20 minutes. After that, it was stirred at the same temperature for about 1 hour, a trace amount of insoluble matter was separated, 60 ml of 42% borohydrofluoric acid aqueous solution was added to the solution, the precipitate was collected, washed with water, and then dried.
15.3 gr (yield: 87%) of hexazonium trifluoroborate was obtained as yellow crystals (decomposition point: about 129°C). Next, 1.2 gr of hexazonium salt obtained as above and 2.7 gr of 2-hydroxy-3-(4-methylphenylcarbamoyl)benzo[a]carbazole were dissolved in 210 ml of DMF, and 2.9 gr of sodium acetate was added to 30 ml of water. was added dropwise at room temperature over about 5 minutes. After the addition was completed, the mixture was stirred at the same temperature for an additional 3 hours, and then the precipitated crystals were collected. The resulting crude crystal cake was dispersed in 300 ml of DMF, stirred at room temperature for 1 hour, then crystals were collected again, and this operation was repeated four times. Thereafter, the crystals are washed with water and dried to obtain the trisazo compound of the present invention.
Obtained 2.0gr (69%). Black crystals Decomposition point Above 300℃ Elemental analysis value Actual value Calculated value C% 75.71 75.99 H% 4.26 4.46 N% 12.54 12.80 Infrared absorption spectrum (KBr tablet method) ν _c=0 (Second amide) 1670cm ^-1 Trisazo of the present invention As mentioned above, the compound is effective as a charge-generating pigment for a laminated photoreceptor, and specific usage examples will be shown below to clarify this point. Further, in order to clarify the inventive step of the present invention, comparisons with conventional azo compounds and comparisons with inorganic photoreceptors are also shown. Application example 76 parts by weight of the trisazo compound of the present invention, a tetrahydrofuran solution (solid content concentration 2%) of polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) 1260
parts by weight and 3,700 parts by weight of tetrahydrofuran were pulverized and mixed in a ball mill, and the resulting dispersion was applied onto the aluminum surface of an aluminum-deposited polyester base (conductive support) using a doctor blade, and air-dried. , a charge generation layer having a thickness of about 1 μm was formed. On the other hand, 1-phenyl-3-(4
-diethylaminostyryl)-5-(4-diethylaminophenyl)pyrazoline, 1 part by weight of polycarbonate resin (Panlite K1300, manufactured by Teijin Corporation), and 8 parts by weight of tetrahydrofuran were mixed and dissolved to form a solution. was applied onto the charge generation layer using a doctor blade and dried at 80°C for 2 minutes and then at 100°C for 5 minutes to a thickness of about 20 μm.
A charge transfer layer was formed, and a laminated photoreceptor A shown in FIG. 4 was prepared. For comparison, according to the above photoreceptor preparation procedure, instead of the trisazo compound of the present invention, 4,4',4, which is a triphenylamine trisazo pigment disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 53-132547, was used. ″−
A photoreceptor was prepared in exactly the same manner except that tris(2-hydroxy-3-phenylcarbamoyl-1-naphthylazo)triphenylamine [comparative pigment (1)] was used, and photoreceptor B was used as a comparative photoreceptor. Obtained. Also, for comparison, the above-mentioned Japanese Patent Application Publication No. 47-37543
4,4'-bis(2-hydroxy-3-phenylcarbamoyl-1-naphthylazo)-3,3'-dichlor, which is a benzidine-based disazo pigment disclosed in Japanese Patent Application Laid-Open No. 52-55643. 1.08 parts by weight of diphenyl [comparative pigment (2)] was dissolved in 24.46 parts by weight of ethylenediamine, and 20.08 parts by weight of n-butylamine was added to this solution with stirring, followed by 54.36 parts by weight of tetrahydrofuran to form a charge generation layer coating solution. Created. Next, this coating solution was applied onto a polyester film coated with aluminum using a doctor blade, and dried at 80° C. for 5 minutes to form a charge generation layer with a thickness of about 0.5 μm. 1-phenyl-3-(4-diethylaminostyryl)-5-(4-diethylaminophenyl) on the charge generation layer.
- 1 part by weight of pyrazoline, 1 part by weight of polycarbonate resin (Panlite K1300, manufactured by Teijin Corporation),
A solution consisting of 8 parts by weight of and tetrahydrofuran was applied with a doctor blade and heated at 80°C for 2 minutes.
Next, it was dried at 100° C. for 5 minutes to form a charge transfer layer with a thickness of about 20 μm, and Comparative Photoreceptor C was prepared. Furthermore, an As ₂ Se ₃ photoreceptor was used as an inorganic comparison photoreceptor, and a Se-As (40wt%) alloy was used as a vapor deposition raw material on an aluminum substrate at a substrate temperature of 200°C and a deposition source temperature of 410 to 415°C for 10 ^-6 Deposited under Torr vacuum,
A photoreceptor having a photosensitive layer of about 60 μm was prepared. The As ₂ Se ₃ photoreceptor thus produced was designated as Photoreceptor D as a comparative photoreceptor. Next, four types of photoreceptors were prepared as described above, namely: 1 Laminated photoreceptor using the trisazo compound of the present invention...Photoreceptor A 2 Laminated photoreceptor using comparative pigment (1)...Photoreceptor B 3 Laminated photoconductor using comparative pigment (2)...Photoconductor C 4 As ₂ Se ₃ photoconductor...Photoconductor D Tested using a commercially available electrostatic copying paper testing device (Model SP-428 manufactured by Kawaguchi Denki Seisakusho) Its electrostatic properties were measured. In other words, first apply -6kV (or +
6kV) corona discharge for 20 seconds to charge it negatively (or positively), then leave it in a dark place for 20 seconds.
Measure the surface potential V _pp (v) at that time, then irradiate the surface with light using a tungsten lamp at an illuminance of 20 lux to determine the surface potential.
Find the time (seconds) it takes to reach 1/2 and 1/10 of V _pp ,
Exposure amounts E1/2 and E1/10 (lux seconds) were calculated. The results are shown in Table 1.

[Table] In addition, the following measurements were performed to demonstrate that the material has extremely high sensitivity to long wavelength light. First, the photoreceptor was charged by corona discharge in a dark place (photoreceptors A, B, and C were negatively charged, and photoreceptor D was positively charged), and its surface potential was measured. Monochromatic light of cm ² was irradiated onto the photoreceptor. And the surface potential is 1/
2 (at this time, the attenuation of the surface potential due to dark decay was corrected), the exposure amount (μw・sec/cm ² ) was determined, and the light decay rate (Volt・cm 2 ) was calculated.
cm ²・μw ^-1・sec ^-1 ) and the results are shown in Table 2.
It was shown to.

【table】

[Table] As is clear from the results in Tables 1 and 2, photoconductor A according to the present invention is comparable in sensitivity to other photoconductors, and is particularly effective for semiconductor lasers. It can be seen that in the wavelength range (around 800 nm), the sensitivity is several ten times higher than that of known photoreceptors. As described above, the trisazo compound of the present invention is an extremely useful material for electrophotographic photoreceptors, and because it is an organic material, it has many advantages such as being lightweight and low cost. , it can be clearly understood that the trisazo compound of the present invention is an extremely excellent material.

[Brief explanation of drawings]

FIG. 1 shows an infrared absorption spectrum of the trisazo compound of the present invention, FIG. 2 shows a thermal analysis diagram, and FIG. 3 shows an X-ray diffraction diagram. FIG. 4 is an example of a photoreceptor in which the trisazo compound of the present invention is used. DESCRIPTION OF SYMBOLS 1... Conductive support, 2... Polyester base, 3... Aluminum vapor deposited film, 4... Charge generation layer, 5... Charge transfer layer.

Claims (1)

[Claims] 1 Formula () A novel trisazo compound represented by 2 formula () By diazotizing 4,4',4''-triaminotriphenylamine represented by the general formula () (However, X represents an anionic functional group.) As a hexazonium salt represented by the following, this hexazonium salt and the formula () Formula () characterized by reacting with 2-hydroxy-3-(4-methylphenylcarbamoyl)benzo[a]carbazole represented by A method for producing a novel trisazo compound represented by