JPH0158180B2 - - 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 applied onto a conductive support by an appropriate method such as vacuum deposition, or by applying a pigment solution or adding a pigment to a resin solution. A charge generation layer is formed as a thin layer by coating a dispersion liquid containing fine particles dispersed therein, and a charge transfer layer is formed on the charge generation layer to which the charge carriers generated in the charge generation layer can be efficiently injected and where the charge carriers can be transferred. (This charge transfer layer usually consists of a charge transfer substance and a binder resin.) Examples of disazo compounds used in this type of photoreceptor include JP-A-47-37543 and JP-A-52-37543.
Benzidine-based disazo pigments disclosed in publications such as No. 55643, triphenylamine-based trisazo pigments disclosed in JP-A-53-132547, and the like are known. However, laminated photoreceptors using these known trisazo pigments and disazo pigments, for example, arsenic selenium (As ₂ Se ₃ )
When compared with inorganic photoreceptors using alloys, they have drawbacks such as low sensitivity and unsuitability as photoreceptors for high-speed copying machines. On the other hand, in recent years, there has been an increasing demand for photoreceptors for laser printers, and in particular, 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 and a method for producing the same. That is, one 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, and a laminated photoreceptor using this compound is comparable in sensitivity to inorganic photoreceptors, and is capable of handling light with a wavelength of 800 nm. It was observed that the response was extremely fast. Figure 1 shows the infrared absorption spectrum (by KBr tablet method) of the trisazo compound [], and Figure 2 shows the thermal analysis diagram (TG-
Fig. 3 shows the X-ray diffraction pattern of the trisazo compound []. In FIG. 2, a is a thermobalance curve, and the area below the curve means weight loss, and b is the differential heat curve, where the upper part of the curve means heat generation and the lower part means heat absorption. 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 following formula [] By diazotizing 4,4′,4″-triaminotriphenylamine represented by the general formula [] (However, X represents an anionic functional group.) A hexazonium salt represented by this and the formula [] This is a method for producing a trisazo compound represented by the formula [], which comprises reacting 2-hydroxy-3-(2-methylphenylcarbamoyl)benzo[a]carbazole represented by the formula []. In this production method, diazotization of 4,4',4''-triaminotriphenylamine is performed by diazotizing it in 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 completed in about 30 minutes to 3 hours.Furthermore, to the reaction mixture, for example, hydroborofluoric acid or an aqueous sodium borofluoride solution is added to precipitate the hexazonium salt. It is preferable to take the crystals and use them in the next reaction.Next, this hexazonium salt is treated with 2-hydroxy-3-(2-methylphenylcarbamoyl)benzo[a]carbazole represented by the formula []. This reaction is carried out by causing a coupling reaction.Actually, 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, and adding about - It is carried out by dropping an alkaline aqueous solution such as aqueous sodium acetate solution at 10°C to 40°C. This reaction is completed in about 5 minutes to 3 hours. After the reaction is completed, the precipitated crystals are collected and an appropriate solution is added. The production of the above trisazo compound is completed by purification by a method (for example, washing with water or/and an organic solvent, recrystallization method, etc.). Production example of a specific trisazo compound according to the present invention produced in this way The following is shown: 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. next,
Cool the mixture to about 0°C and add sodium nitrite to
A solution of 2.7 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. Thereafter, the mixture was stirred at the same temperature for about 1 hour, a trace amount of insoluble matter was separated, and this liquid was added with a 42% aqueous borofluoric acid solution.
60 ml was added, the precipitate was collected, washed with water, dried, and 15.3g (yield: 87%) of hexazonium trifluoroborate was obtained as yellow crystals (decomposition point: approx. 129).
℃). Subsequently, the hexazonium salt thus obtained
1.2gr and 2.7gr of 2-hydroxy-3-(2-methylphenylcarbamoyl)benzo[a]carbazole were dissolved in 210ml of DMF, and a solution of 2.9gr of sodium acetate dissolved in 30ml of water was added to the solution at room temperature for about 5g. It was dripped in 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, and 2.1g of the trisazo compound of the present invention was prepared.
(72%). This product was a black crystal with a decomposition point of 300°C or higher, and its infrared absorption spectrum (KBr tablet method) was Vc = o (secondary amide) 1670 cm ^-1 .

[Table] As is known, the trisazo compound of the present invention is
It is extremely effective as a charge-generating pigment for laminated photoreceptors, and because it is an organic material, it has many advantages such as light weight and low cost. Next, application examples and comparative examples are shown. Note that all parts are parts by weight. Application example 1 76 parts of trisazo compound represented by formula [],
Polyester resin (Vylon 200, manufactured by KK Toyobo) in tetrahydrofuran solution (solid content concentration 2)
%) and 3,700 parts 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-(4-diethylaminostyryl)-5-(4-diethylaminophenyl)
Pyrazoline 1 part polycarbonate resin (Panlite K1300,
A charge transfer layer coating solution was prepared by mixing and dissolving 1 part (manufactured by Teijin) and 8 parts of tetrahydrofuran. This solution is applied onto the charge generation layer with a doctor blade, and dried at 80°C for 2 minutes and at 100°C for 5 minutes to form a charge transport layer with a thickness of about 20 μm,
A laminated type photoreceptor (A) shown in FIG. 4 was prepared. Comparative Example 1 According to the photoreceptor preparation procedure in Application Example 1, 4,4, which is a triphenylamine trisazo pigment disclosed in JP-A-53-132547, was used instead of the trisazo compound represented by the formula []. ′、
A laminated photoreceptor (B) was prepared in exactly the same manner except that 4″-tris(2-hydroxy-3-phenylcarbamoyl-1-naphthylazo)triphenylamine [comparative pigment (1)] was used. Comparative Example 2 JP-A-47-37543 or JP-A-52-
4,4′-bis(2-hydroxy-
3-phenylcarbamoyl-1-naphthylazo)
-3,3'-dichlorodiphenyl [Comparative pigment (2)]
A charge generation layer coating solution was prepared by dissolving 1.08 parts in 24.46 parts of ethylenediamine, adding 2.0.08 parts of n-butylamine to this solution with stirring, and further adding 54.36 parts of tetrahydrofuran. Next, this coating solution was applied onto a polyester film (conductive support) on which aluminum was vapor-deposited 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. Furthermore, 1-phenyl-3
-(4-diethylaminostyryl)-5-(4-
A solution consisting of 1 part of (diethylaminophenyl)-pyrazoline, 1 part of polycarbonate resin (Panlite K-1300: manufactured by Teijin Kasei KK), and 8 parts of tetrahydrofuran was applied with a doctor blade, and
It was dried at 100° C. for 2 minutes and then for 5 minutes at 100° C. to form a charge transfer layer with a thickness of about 20 μm, thereby producing a laminated photoreceptor (C). Comparative Example 3 A Se-As (AS content is approximately 40 wt%) alloy was placed on an aluminum substrate (conductive support) at a substrate temperature of 200°C.
An inorganic photoreceptor (D) having an AS ₂ Se ₃ photosensitive layer of about 60 μm was produced by vapor deposition at a vapor deposition source temperature of 410 to 415° C. under a vacuum of 10 ⁻⁶ Torr. Next, the electrostatic properties of the four types of photoreceptors (A, B, C, D) prepared as described above were measured using a commercially available electrostatic copying paper tester (Model SR-428 manufactured by Kawaguchi Electric Seisakusho). It was 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 Vpo (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 Vpo,
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 light of the highest wavelength. First, the photoconductor is charged by corona discharge in a dark place (photoconductors (A), (B), and (C) are negatively charged, and photoconductor (D) is positively charged), and its surface potential is measured. The photoreceptor was irradiated with monochromatic light of 1 μW/cm ² that was spectrally dispersed using a meter. 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 decay rate (Volt・cm ²・μW ⁻¹・sec ⁻¹ ) was calculated. The results are shown in Table-2.

【table】

[Table] As is clear from the results in Tables 1 and 2, the photoreceptor (A) according to the present invention is different from other photoreceptors (photoreceptors).
Compared to (B), (C), and (D), it is comparable in sensitivity, and is several times more sensitive than known photoreceptors, especially in the wavelength range of semiconductor lasers (around 800 nm). It can be seen that it has sensitivity.

[Brief explanation of drawings]

Figures 1, 2 and 3 respectively show the infrared absorption spectra of the trisazo compound according to the present invention;
A thermal analysis diagram and an X-ray diffraction diagram are shown, and FIG. 4 is a cross-sectional view of a representative example of a photoreceptor using the trisazo compound according to 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. The following 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 this and the formula [] The following formula [] characterized by reacting with 2-hydroxy-3-(2-methylphenylcarbamoyl)benzo[a]carbazole represented by
A method for producing a trisazo compound represented by