JPH0158181B2 - - 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 (generally, the charge transfer layer consists of a charge transfer substance and a binder resin) is formed.
Conventionally, disazo compounds used in this type of photoreceptor include benzidine-based disazo pigments disclosed in, for example, JP-A-47-37543 and JP-A-52-55643; A triphenylamine trisazo pigment disclosed in Japanese Patent Publication No. 132547/1984 is well known. However, conventional laminated photoreceptors using trisazo pigments or disazo pigments have low 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 disadvantages such as not being suitable for the body. In addition, the demand for photoreceptors for laser printers has increased in recent years, and there is an urgent need to develop photoreceptors with high sensitivity in the wavelength range of semiconductor lasers. An object of the present invention is to provide a novel trisazo compound that is effective in the above-mentioned laminated photoreceptor. Another object of the present invention is to provide a method for producing the above trisazo compound. It was found that 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. That is, one of the present invention is the formula [] It is a trisazo compound shown by This new trisazo compound is a black crystalline substance at room temperature. Figure 1 shows the infrared absorption spectrum (KBr tablet method) of the compound of formula [], Figure 2 shows the thermal analysis diagram (by TG-DSC), and Figure 3 shows the X-ray diffraction diagram. . In Figure 2, curve A is a thermobalance curve;
Curve B shows 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 the formula [] By diazotizing 4,4′,4″-triaminotriphenylamine represented by the general formula [] (However, X represents an anionic functional group.) A hexazonium salt represented by the formula [] This is a method for producing a trisazo compound represented by the above formula [], which comprises reacting with 2-hydroxy-3-phenylcarbamoylbenzo[a]carbazole represented by the formula []. In this manufacturing method, 4, 4′, 4″ of the formula []
Diazotization of triaminotriphenylamine is carried out by adding an aqueous solution of sodium nitrite in a dilute inorganic acid such as dilute hydrochloric acid or dilute sulfuric acid at -10°C to 10°C. This diazotization reaction is completed in approximately 30 minutes to 3 hours. Furthermore, it is desirable to add, for example, hydroborofluoric acid or an aqueous sodium borofluoride solution to the reaction mixture to precipitate the hexazonium salt of formula [], and use it in the next reaction after crystallizing it. Next, this hexazonium salt is reacted with 2-hydroxy-3-phenylcarbamoylbenzo[a]carbazole of formula [] to cause a coupling reaction. In reality, this reaction is carried out by mixing and dissolving a hexazonium salt and coupler in an organic solvent such as N,N-dimethylformamide (DMF) or dimethyl sulfoxide, and adding an aqueous solution of sodium acetate to this mixture at about -10°C to 40°C. This is done by dropping an alkaline aqueous solution. This reaction is complete in approximately 5 minutes to 3 hours. After completion of the reaction, the precipitated crystals are collected and purified by an appropriate method (for example, washing with water and/or an organic solvent, recrystallization method, etc.) to complete the production of the trisazo compound of the above formula []. 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 8.7
Add gr 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. The mixture was then cooled to approximately 0°C and sodium nitrite was added to 7.7°C.
A solution of gr dissolved in 30 ml of water was added dropwise over a period of about 20 minutes at a temperature of -3° to 2°C. After that, stir at the same temperature for about 1 hour to remove traces of insoluble matter and turn it into a liquid.
Add 60ml of 42% borohydrofluoric acid aqueous solution, remove the precipitate, wash with water, and dry to give 15.3g (yield).
87%) of hexazonium trifluoroborate was obtained as yellow crystals (decomposition point: approximately 129°C). Next, the hexazonium salt obtained as above
1.2 gr and 2.5 gr of 2-hydroxy-3-phenylcarbamoylbenzo[a]carbazole.
Dissolve in 210ml of DMF and add 2.9ml of sodium acetate to this.
A solution of gr dissolved in 30 ml of water 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, the crystals were collected again.
This operation was repeated four more times. Thereafter, the crystals were washed with water and dried to obtain 1.5 gr (yield: 53%) of the trisazo compound of the present invention as black crystals. Decomposition point: 300℃ or higher Elemental analysis value: Actual value Calculated value C% 75.53 75.69 H% 3.98 4.16 N% 12.85 13.19 Infrared absorption spectrum (KBr tablet method) Vc=o (secondary amide) 1670 cm ^-1 Trisazo compound of the present invention As mentioned above, it is effective as a charge-generating pigment for laminated photoreceptors, and to clarify this point, specific application examples are shown below. Further, in order to clarify the inventive step of the present invention, a comparison with conventional azo compounds or an inorganic photoreceptor is also shown. Application example: 76 parts by weight of the trisazo compound of the present invention, polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.)
Tetrahydrofuran solution (solid content concentration 2%)
1,260 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 with a thickness of about 1 μm was formed. On the other hand, 1-phenyl-3-
1 part by weight of (4-diethylaminostyryl)-5-(4-diethylaminophenyl)pyrazoline, 1 part by weight of polycarbonate resin (Panlite K1300, manufactured by Teijin Ltd.), and 8 parts by weight of tetrahydrofuran.
After mixing and dissolving parts by weight to form a solution, this was applied onto the charge generation layer using a doctor blade and heated at 80°C.
Dry for 2 minutes at 100°C for 5 minutes to a thickness of approximately 20μm.
A charge transfer layer was formed, and a laminated photoreceptor (A) shown in FIG. 4 was prepared. For comparison, the above photoreceptor preparation procedure was followed, and 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 comparative photoreceptor (B) was prepared in exactly the same manner except that tris(2-hydroxy-3-phenylcarbamoyl-1-naphthylazo)triphenylamine [comparative pigment (1)] was used. Therefore, the above-mentioned Japanese Patent Application Laid-open No. 47-37543
4,4'-bis(2-hydroxy-3-phenylcarbamoyl-
1-naphthylazo)-3,3'-dichlorophenyl [comparative pigment (2)] 1.08 parts by weight of ethylenediamine
20.08 parts by weight of n-butylamine was added to this solution with stirring, and 54.36 parts by weight of tetrahydrofuran was further added to prepare a charge generation layer coating solution. Next, this coating solution was applied onto a polyester film coated with aluminum using a doctor blade, dried at 80℃ for 5 minutes, and the thickness was approx.
A charge generation layer of 0.5 μm was formed. 1-phenyl-3-(4-diethylaminostyryl)-5-(4-diethylaminophenyl) on the charge generation layer.
- 1 part by weight of pyrazoline, 1 part of polycarbonate resin (Panlite K-1300: manufactured by Teijin Kasei Ltd.)
A solution consisting of 1 part by weight and 8 parts by weight of tetrahydrofuran was applied with a doctor blade and heated at 80℃ for 2 hours.
minutes, then dried at 100℃ for 5 minutes to a thickness of approximately 20μm.
A comparative photoreceptor (C) was prepared by forming a charge transfer layer. Furthermore, for comparison, a Se-As (40 wt%) alloy was deposited on an aluminum substrate as a deposition raw material under a vacuum of 10 ^-6 Torr at a substrate temperature of 200°C and a deposition source temperature of 410 to 415°C. As ₂ Se ₃ with photosensitive layer
A photoreceptor was created. The inorganic photoreceptor thus produced was designated as a comparison photoreceptor (D). Next, four types of photoreceptors were prepared as described above, namely: 1. A laminated photoreceptor using the trisazo compound of the present invention...Photoreceptor (A) 2. A laminated photoreceptor using the comparative pigment (1)
...Photoreceptor (B) 3 Laminated photoreceptor using comparative pigment (2)
...Photoconductor (C) 4 As ₂ Se ₃ Photoconductor ...The electrostatic properties of the photoconductor (D) were measured using a commercially available electrostatic copying paper testing device (Model SP-428 manufactured by Kawaguchi Denki Seisakusho). . In other words, first apply -6KV (or +
After performing a corona discharge of 6KV for 20 seconds to charge it negatively (or positively), leave it in a dark place for 20 seconds, measure the surface potential Vpo (V) at that time, and then charge it with a tungsten lamp. Surface illuminance 20
Irradiate light so that the surface potential becomes 1/2 and 1/10 of Vpo, and calculate the exposure amount E1/2 and E1/10 (lux seconds). did. The results are shown in Table 1.

[Table] In order to investigate the sensitivity of the above photoreceptor to long wavelength light, the following measurements were performed. First, the photoreceptor is charged by corona discharge in a dark place (photoreceptors (A), (B), and (C) are negatively charged, and photoreceptor (D) is positively charged), and its surface potential is measured. Spectroscopy was performed using a monochromator.
Monochromatic light of 1 μW/cm ² was irradiated. Then, the time (seconds) until the surface potential attenuates to 1/2 is determined (at this time, the attenuation of the surface potential due to dark decay is corrected), the exposure amount (μW.sec/cm ² ) is determined, and the amount of light is The attenuation rate (Volt・cm ²・μW ⁻¹・sec ⁻¹ ) was calculated and the results are shown in Table 2.

[Table] As is clear from the results in Tables 1 and 2, the photoreceptor (A) according to the present invention is comparable in sensitivity to other photoreceptors, and is particularly suitable for semiconductor lasers. It can be seen that in the wavelength range (around 800 nm), the sensitivity is several times higher than that of known photoreceptors. 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]

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 shows an example of the structure of a photoreceptor which is an example of the use of the trisazo compound of the present invention. 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 trisazo compound represented by 2 formula [] By diazotizing 4,4′,4″-triaminotriphenylamine represented by the general formula [] (However, X represents an anionic functional group.) A hexazonium salt represented by the formula [] Formula [] characterized by reaction with 2-hydroxy-3-phenylcarbamoylbenzo[a]carbazole represented by A method for producing a trisazo compound shown in