JPS648031B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to novel disazo compounds. BACKGROUND ART Inorganic photoreceptors using inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been widely used in electrophotography. ``Electrophotography'' generally refers to a method in which a photoconductive photoreceptor is first charged in a dark place by corona discharge, etc., and then subjected to imagewise exposure to selectively discharge the charges in the exposed areas, leaving the unexposed areas free of electrostatic charge. This is one of the image forming methods in which an image is left behind and this latent image is visualized by a developing means using toner or the like to form an image. The basic characteristics required of the photoreceptor used in such electrophotography are (1) ability to be appropriately charged in the dark, (2) excellent charge retention in the dark, and ability to discharge the charge. (3) high photosensitivity and rapid discharge of charges upon irradiation with light; and excellent mechanical strength and flexibility. Although the conventional inorganic photoreceptors have several advantages, they also have various disadvantages. For example, the selenium photoreceptors currently widely used are (1) to
Although the condition (3) is satisfied to a considerable extent, the mechanical strength and flexibility are not satisfactory. In particular, as a variety of processes have been adopted in recent electrophotography methods, photoreceptors that are compatible with all of these processes have become required, and for example, flexible shapes are required. However, the selenium photoreceptor has low flexibility and is difficult to produce in such a shape. Similar drawbacks can also be cited for inorganic photoreceptors other than selenium photoreceptors. In recent years, in order to eliminate the drawbacks of these inorganic photoreceptors, organic electrophotographic photoreceptors using various organic photoconductive materials have been researched and developed, and have been put into practical use. For example, poly-N-vinylcarbazole and 2,4,7-trinitrofluorene-9 on a support.
Photoreceptor with a photosensitive layer containing poly-N-vinyl carbazole sensitized with a pyrylium salt dye (Japanese Patent Publication No. 48-25658) (see JP-A-47-37543), a photoreceptor provided with a photosensitive layer containing a disazo pigment as its main component (see JP-A-47-37543), and a photoreceptor provided with a photosensitive layer containing a eutectic complex consisting of a dye and a resin as its main component. Examples include photoreceptors (see Japanese Patent Application Laid-open No. 10735/1983). Although these organic photoreceptors have improved the mechanical properties and flexibility of the inorganic photoreceptors to some extent, they generally have low photosensitivity and do not fully satisfy the requirements for electrophotographic photoreceptors. In general, the characteristics of an electrophotographic photoreceptor are greatly influenced by the materials used, the manufacturing method, etc., but they are particularly dependent on the photoconductive material. For this reason, research into photoconductive materials has been actively conducted, and the present invention also relates to this. An object of the present invention is to provide a novel disazo compound which is particularly useful as a photoconductive material and which solves the drawbacks of the conventional photoconductive materials for photoreceptors. (However, R represents hydrogen, an alkyl group, an alkoxyl group, a nitro group, a dialkylamino group, or a halogen, and n is an integer of 1, 2 or 3,
When n is 2 or 3, R may be the same or different groups. ) is a disazo compound represented by This disazo compound has the formula The diamino compound represented by is diazotized to form the formula (However, X represents an anionic functional group.) (However, R represents hydrogen, lower alkyl, lower alkoxyl group, nitro group, chlorine or bromine, and n
is an integer of 1, 2 or 3, and n is 2 or 3
In this case, R may be the same or different groups. ) It can be produced by reacting with the compound shown below. The disazo compound of the present invention represented by the above general formula is a novel compound that forms colored crystals at room temperature. Specific examples thereof are shown in Table 1 below along with melting points, elemental analysis values, and infrared absorption spectrum data.

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[Table] To actually produce the disazo compound of the general formula according to this method, the compound of the general formula (sometimes referred to as a coupling component) and the tetrazonium salt of the formula are mixed with N,N-dimethylformamide,
Dissolved in an organic solvent such as dimethyl sulfoxide,
An alkaline aqueous solution such as an aqueous solution of sodium acetate may be added dropwise to this at a temperature of about -10°C to 20°C. The reaction is completed in 5 to 30 minutes, and the desired disazo compound of the present invention is obtained. The appropriate amount of the compound of the general formula to be used is about 2 to 5 moles per 1 mole of the compound of the formula. Compounds of formula can also be obtained by diazotization of compounds of formula. This is accomplished, for example, by adding an aqueous solution of sodium nitrite in a dilute inorganic acid such as dilute hydrochloric acid or dilute sulfuric acid to the compound of the formula at a temperature of about -10°C to 10°C. This diazotization reaction is completed in 30 minutes to 3 hours. Furthermore, it can be precipitated as a tetrazonium salt by adding, for example, borofluoric acid, and then taken out as crystals. The disazo compound of the present invention obtained as described above is particularly useful as a photoconductive material for electrophotographic photoreceptors. Thus, for example, (1) the disazo compound is mixed with a suitable resin binder such as polyester, polyamide, polyurethane, polyketone, polycarbonate, polystyrene, polyvinyltoluene, etc. in fine particles (about 0.05 mm in diameter).
(2) In addition to the above system (1), an inorganic photoconductive material (e.g., known cadmium sulfide, cadmium sulfide-selenium, etc.) is added to the system (1) above. or a photoreceptor to which an organic photoconductive material (e.g., known poly-N-vinylcarbazole, polyvinylpyrene, etc.) has been added; Examples of applications of the new disazo compound include a laminated type photoreceptor formed by a photoreceptor method and a layer of another photoconductive substance formed thereon. The photoreceptor produced in this manner is no inferior to conventional photoreceptors and can fully achieve the object of the present invention. Next, the effects of the novel disazo compound of the present invention will be explained using an example of its use in a photoreceptor. 2 parts by weight of Compound No. 1 disazo compound and 98 parts by weight of tetrahydrofuran were pulverized and mixed in a ball mill, and the resulting dispersion was applied onto an aluminum-deposited polyester film with a doctor blade and air-dried to generate a charge with a thickness of 1μ. formed a layer. On the other hand, 2 parts by weight of 9-(4-diethylaminostyryl)anthracene and polycarbonate resin [Co., Ltd.
2 parts by weight of Panlite L manufactured by Teijin were dissolved in 16 parts by weight of tetrahydrofuran, and this was applied onto the charge generation layer using a doctor blade and dried at 120°C for 10 minutes to form a charge transfer layer with a thickness of 15μ, and then laminated. A type photoreceptor was obtained. Next, a -6KV corona discharge was applied to the photosensitive layer surface of this photoreceptor using a commercially available electrostatic copying paper tester for 20 seconds to negatively charge it, and then it was left in a dark place for 20 seconds. ), then irradiate the photosensitive layer with light from a tungsten lamp so that the surface potential is 20 lux, find the time (seconds) until the surface potential becomes 1/2 of Vpo, and calculate the halving exposure time. It was set as T1/2 (seconds). The result was Vpo 822 volts T1/2 1.2 seconds. Examples of the present invention are shown below. Example 1 6.4 gr of the diamino compound represented by the formula was added to dilute hydrochloric acid prepared from 30 ml of concentrated hydrochloric acid and 30 ml of water,
The temperature was maintained at about 60-70°C for 30 minutes and then cooled to about -5°C. Then, a solution of 3.3 gr of sodium nitrite dissolved in 30 ml of water was dropped over a period of about 25 minutes at a temperature of 0 to -7°C. After that, the mixture was stirred at the same temperature for about 1 hour, and the orange-yellow precipitate formed was collected.
It was dissolved in 500ml. Separate a small amount of insoluble part,
18 ml of a 42% borohydrofluoric acid aqueous solution was added to the solution, and the precipitated yellow precipitate was collected, washed with water, and dried to obtain 6.2 gr (yield: 60%) of a tetrazonium salt. Next, 1.04 gr of this tetrazonium salt and 1.26 gr of 2-hydroxy-3-naphthoic acid anilide as a coupling component were dissolved in 300 ml of N,N-dimethylformamide, and a solution consisting of 2.0 gr of sodium acetate and 30 ml of water was added to the solution for 15 min. After dropping at a temperature of ~26°C for 15 minutes, the mixture was stirred for a further 3 hours at room temperature. After that, the precipitate was collected, washed five times with 300 ml of N,N-dimethylformamide, and washed twice with 400 ml of water.
After washing twice, it was dried at 100℃ and under a reduced pressure of 2mmHg to produce 1.2gr of Compound No. 1 disazo compound (yield 69%).
I got it. Infrared absorption spectrum (KBr tablet method)
is shown in Figure 1. Examples 2 to 20 Various disazo compounds of the present invention were produced in the same manner as in Example 1, except that the listed compounds were used as coupling components. Among these disazo compounds, the infrared absorption spectra of compounds No. 2, 4, and 7 are shown in Figures 2 to 4, respectively.

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【table】 [Brief explanation of drawings]

Figures 1 to 4 are infrared absorption spectra (KBr tablet method) of each disazo compound. Figure 1…No.
1 Disazo compound, Figure 2...No.2 Disazo compound, Figure 3...No.4 Disazo compound, Figure 4...
No.7 Disazo compound.

Claims (1)

[Claims] 1. General formula (However, R represents hydrogen, lower alkyl group, lower alkoxyl group, nitro group, chlorine or bromine,
n is an integer of 1, 2 or 3, and when n is 2 or 3, R may be the same or different groups. ) A disazo compound represented by