JPH0356263B2 - - 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, benzine-based disazo pigments disclosed in, for example, JP-A-47-37543 or JP-A-52-55643, or JP-A-Sho. 53
A triphenylamine trisazo pigment disclosed in Japanese Patent No. 132547 is well known. However, conventional laminated photoreceptors using trisazo pigments and disazo pigments have lower sensitivity than inorganic photoreceptors using arsenic selenium (As ₂ Se ₃ ) alloys, making them difficult to use in high-speed copying machines. It has disadvantages such as not being suitable for the body. 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. An object of the present invention is to provide a novel trisazo compound that is effective even in the semiconductor laser wavelength range in the above-mentioned laminated photoreceptor. Another object of the present invention is to provide a method for producing the above trisazo compound. The inventors of the present invention have conducted intensive research on numerous disazo compounds and trisazo compounds with the aim of developing charge-generating pigments that are highly sensitive and have almost flat sensitivity over the entire visible light and semiconductor laser wavelength ranges. As a result, even in the trisazo compound represented by the following general formula [], the properties differ greatly depending on the type or position of the substituent in R, and it was found that the trisazo compound where R is as shown below has excellent properties. I found it. That is, the present invention is based on the following general formula [] (However, R is

【formula】

【formula】

【formula】

Represents [formula]. ) is a trisazo compound represented by This new trisazo compound is a black crystalline substance at room temperature. The laminated photoreceptor using the trisazo compound of the present invention is comparable in sensitivity to inorganic photoreceptors, and has an extremely fast response to light with a wavelength of 800 nm. For the purpose of the following explanation, the trisazo compounds of the present invention are indicated.

[Table] Figures 1-1 to 1-4 show the infrared absorption spectra (KBr tablet method) of the above trisazo compounds -1 to -4, and Figures 2-1 to 2 to 4 show the thermal analysis diagrams (TG -DSC) and X-ray diffraction patterns are shown in Figures 3-1 to 3-4. In addition, in Figure 2, curve A
is a thermobalance curve, and curve B is a differential thermal curve. The above trisazo compound of the present invention can be produced by the following method. That is, another aspect of the present invention is 4,4',4''-triaminophenylamine represented by the formula [] is diazotized to form a hexazonium salt represented by the general formula [], (However, X represents an anionic functional group.) This and a 2-hydroxy-3-phenylcarbamoylbenzo[a]carbazole derivative represented by the general formula [] (However, R is the same as above.) This is a method for producing a trisazo compound represented by the general formula [], which is characterized by reacting with: In this production method, 4,4',4''-triaminotriphenylamine is diazotized by adding a sodium nitrite aqueous solution in a dilute inorganic acid such as dilute hydrochloric acid or dilute sulfuric acid at -10°C to 10°C. This diazotization reaction is carried out by adding
It takes approximately 30 minutes to 3 hours to complete. Furthermore, it is preferable to add, for example, hydroborofluoric acid or an aqueous sodium borofluoride solution to the reaction mixture to precipitate a tetrazonium salt, and use the crystals after crystallization in the next reaction. Next, 2-hydroxy- of the general formula [] is added to this tetrazonium salt.
This is carried out by reacting a 3-phenylcarbamoylbenzo[a]carbazole derivative to cause a coupling reaction. In reality, this reaction is carried out by mixing and dissolving a tetrazonium 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 1 4,4′,4″-triaminotriphenylamine 8.7
g to dilute hydrochloric acid prepared from 150 ml of concentrated hydrochloric acid and 130 ml of water, and stir well at room temperature for about 30 minutes. This mixture was then cooled to approximately 0°C and 7.7 g of sodium nitrite was added.
is dissolved in 30 ml of water at a temperature of -3° to 2°C.
The mixture was added dropwise over 20 minutes. After that, the mixture was stirred at the same temperature for about 1 hour, a trace amount of insoluble liquid was separated, and 60 ml of 42% borohydrofluoric acid aqueous solution was added to the liquid. ) was obtained as yellow crystals (decomposition point: approximately 129°C). Next, the hexazonium salt obtained as above
1.2g and 2.9g of 2-hydroxy-3-(2-methyl-5-chlorophenylcarbamoyl)benzo[a]carbazole were dissolved in 210ml of DMF,
To this, 2.9 g of sodium acetate was dissolved in 30 ml of water, and the solution was added dropwise at room temperature over about 5 minutes. After the addition was completed, the mixture was further stirred at the same temperature for 3 hours, and then the precipitated crystals were collected. Disperse the obtained crude crystal cake in 300ml of DMF,
After stirring at room temperature for 1 hour, crystals were collected again, and this operation was repeated 4 times. Thereafter, the crystals were washed with water and dried to obtain the trisazo compound (-1) of the present invention.
2.4g (78%) was obtained. Black crystal Decomposition point 300℃ or higher Elemental analysis value Actual value Calculated value C % 70.50 70.84 H % 3.76 3.96 N % 11.92 11.93 Infrared absorption spectrum (KBr tablet method) νc = 0 (secondary amide) 1680 cm ^-1 Production example 2 2-hydroxy-3-(2-
The same procedure was repeated except that 2.9 g of 2-hydroxy-3-(2-ethoxyphenylcarbamoyl)benzo[a]carbazole was used instead of 2.9 g of methyl-5-chlorophenylcarbamoyl)benzo[a]carbazole. The trisazo compound of the invention (-
2) Obtained 2.3g (76%). Black crystal Decomposition point 300℃ or higher Elemental analysis value Actual value Calculated value C % 73.59 73.84 H % 4.56 4.60 N % 11.79 12.04 Infrared absorption spectrum (KBr tablet method) νc = 0 (secondary amide) 1670 cm ^-1 Production example 3 Production 2-hydroxy-3-(2-
Same procedure except that 2.7 g of 2-hydroxy-3-(2,5-dimethylphenylcarbamoyl)benzo[a]carbazole was used instead of 2.9 g of methyl-5-chlorophenylcarbamoyl)benzo[a]carbazole. The trisazo compound of the present invention (
-3) 1.9g (65%) was obtained. Black crystal Decomposition point 300℃ or higher Elemental analysis value Actual value Calculated value C % 76.09 76.26 H % 4.61 4.75 N % 11.93 12.43 Infrared absorption spectrum (KBr tablet method) νc = 0 (secondary amide) 1680 cm ^-1 Production example 4 Production 2-hydroxy-3-(2-
Same procedure except that 2.7 g of 2-hydroxy-3-(2,4-dimethylphenylcarbamoyl)benzo[a]carbazole was used instead of 2.9 g of methyl-5-chlorophenylcarbamoyl)benzo[a]carbazole. The trisazo compound of the present invention (
-4) 2.0g (68%) was obtained. Black crystal Decomposition point 300℃ or higher Elemental analysis value Actual value Calculated value C % 76.41 76.26 H % 4.46 4.75 N % 11.93 12.43 Infrared absorption spectrum (KBr tablet method) νc = 0 (secondary amide) 1680 cm ^-1 Trisazo of the present invention As mentioned above, the compound is effective as a charge-generating pigment for a laminated photoreceptor, and specific application examples will be shown below to clarify this point. In addition, in order to clarify the inventive step of the present invention, comparisons with conventional azo compounds and with inorganic photoreceptors are also shown. Application example 76 parts by weight of the trisazo compound (-1) of the present invention, 1260 parts by weight of a tetrahydrofuran solution (solid content concentration 2%) of polyester resin (Vylon 20, manufactured by Toyobo Co., Ltd.), and tetrahydrofuran
3,700 parts by weight 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, air-dried, and a thickness of approx.
A charge generation layer of 1 μm was formed. On the other hand, 9-(4-
1 part by weight of anthracene (diethylaminophenyl), polycarbonate resin (Panlite K1300,
After preparing a solution by mixing 1 part by weight (manufactured by Teijin Corporation) and 8 parts by weight of tetrahydrofuran, this was applied onto the charge generation layer using a doctor blade, and then dried at 80°C for 2 minutes and then at 100°C for 5 minutes. A charge transfer layer having a thickness of about 20 μm was formed to produce a laminated photoreceptor (A) shown in FIG. 4. In addition, laminated photoreceptors (B) to (D) were prepared in the same manner as in the above application example except for the combinations shown in the table below.

[Table] Next, the following photoreceptors were prepared for comparison. Comparative Example 1 Instead of the trisazo compound of the present invention, 4,4′,4″-, which is the triphenylamine trisazo pigment disclosed in JP-A-53-132547, was used.
A method completely similar to the above application example, except that tris(2-hydroxy-3-phenylcarbamoyl-1-naphthylazo)triphenylamine was used and 9-(4-diethylaminophenyl)anthracene was used as the charge transfer substance. A comparative photoreceptor (E) was prepared. Comparative Example 2 1-phenyl-3-(4-diethylaminostyryl)-5 was used instead of the charge transfer substance in Comparative Example 1.
A comparative photoreceptor was prepared in the same manner as in Comparison 1 except that -(4-diethylaminophenyl)-pyrazoline was used.
(F) was created. Comparative Example 3 10 parts by weight of polyester resin, 10 parts by weight of 2,4,7-trinitro-9-fluorenone, a trisazo compound of the present invention in which R is a 2-methyl-4-methoxyphenyl group ( Tokukai Akira
2 parts by weight of the trisazo compound disclosed in No. 53-132347 and 198 parts by weight of tetrahydrofuran were pulverized and mixed in a ball mill, and the resulting dispersion was applied onto a polyester film coated with aluminum using a doctor blade. 10 at 100℃
A comparison photoreceptor (G) having a photosensitive layer with a thickness of 10 μm was prepared by drying for 1 minute. Comparative Example 4 4,4′-bis(2-hydroxy-
3-phenylcarbamoyl-1-naphthylazo)
1.08 parts by weight of -3,3'-dichlorodiphenyl was dissolved in 24.46 parts by weight of ethylenediamine, and 20.08 parts by weight of n-butylamine was added to this solution while stirring, followed by 54.36 parts by weight of tetrahydrofuran to form a charge generation layer coating solution. It was 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. On the charge generation layer, 1 part by weight of 1-phenyl-3-(4-diethylaminostyryl)-5-(4-diethylaminophenyl)-pyrazoline and 1 part by weight of polycarbonate resin (Panlite K-1300; manufactured by Teijin Kasei Ltd.) were added. A solution consisting of 1 part by weight and 8 parts by weight of tetrahydrofuran was applied with a doctor blade,
℃ for 2 minutes, then 100℃ for 5 minutes to a thickness of approx.
A charge transfer layer of 20 μm was formed, and a comparative photoreceptor (H) was prepared. Comparative Example 5 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 vapor deposition source temperature.
Deposited under a vacuum of 10 ^-6 Torr at 410-415°C, approx.
An As ₂ Se ₃ photoreceptor having a photosensitive layer of 60 μm was prepared. This inorganic comparative photoreceptor is designated as (I). Next, the electrostatic properties of the nine types of photoreceptors prepared as described above were measured using a commercially available electrostatic copying paper tester (Model SP-428 manufactured by Kawaguchi Electric Seisakusho). In other words, first apply -6KV (or +
After 20 seconds of corona discharge (6KV) to negatively (or positively) charge the sample, leave it in a dark place for 20 seconds, measure the surface potential V _p0 (V) at that time, and then use a tungsten lamp to charge the sample. Its surface has an illuminance of 20
Irradiate light so that the surface potential becomes 1/2 and 1/10 of V _p0 , and calculate the amount of exposure E1/2 and E1/10 (lux seconds). Calculated. The results are shown in Table-3.

[Table] Furthermore, in order to clarify that the photoreceptor of the present invention has extremely excellent sensitivity to long wavelength light, the following measurements were performed. First, the photoreceptor is charged by corona discharge in a dark place (photoreceptors (A) to (H) are negatively charged, photoreceptor (I) is positively charged), and its surface potential is measured. Then, using a monochromator, The photoreceptor was irradiated with 1 μw/cm ² monochromatic light. 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 degree of light attenuation (volt・cm 2} ) was calculated.
cm ²・μw ^-1・sec ^-1 ) and the results are shown in Table 4.
It was shown to.

【table】

[Table] As is clear from the results in Tables 3 and 4, the photoreceptors (A) to (D) according to the present invention are inferior to other photoreceptors in terms of sensitivity in the visible light region. It can be seen that the sensitivity is several tens of times higher, especially in the wavelength range of semiconductor lasers (around 800 nm). As mentioned 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]

Figures 1-1 to 1-4 show formula (-1) of the present invention ~
(-4) Infrared absorption spectrum of trisazo compound, Figures 2-1 to 2-4 are thermal analysis diagrams, Figure 3-
Figures 1 to 3-4 show X-ray diffraction patterns. FIG. 4 shows an example of the structure of a photoreceptor which is an example of the use of the trisazo compound of the present invention. DESCRIPTION OF SYMBOLS 1... Conductive support, 2... Polyester base, 3... Aluminum vapor deposited film, 4... Charge generation layer, 5... Charge transfer layer, Curve A... Thermobalance curve,
Curve B...Differential thermal curve.

Claims (1)

[Claims] 1. Trisazo compound represented by the general formula [] (However, R represents [formula] [formula] [formula] [formula].) 2 4,4',4''-triaminophenylamine represented by formula [] is diazotized to form a hexazonium salt represented by the general formula [], (However, X represents an anionic functional group.) This and 2-hydroxy-3 represented by the general formula []
-Phenylcarbamoylbenzo[a]carbazole derivative (However, R is the same as above.) A method for producing a trisazo compound represented by the general formula [], which comprises reacting with: (However, R is the same as above.)