JPH0784565B2 - Disazo compound - Google Patents

Description

TECHNICAL FIELD The present invention relates to a disazo compound.

2. Description of the Related Art Conventionally, it has been known that a certain kind of disazo compound is effective as a charge generation pigment used in a charge generation layer of a laminated type photoreceptor which is one form of an electrophotographic photoreceptor. The term "multilayer type photoreceptor" as used herein means a charge generating pigment having the ability to generate charge carriers by light on a conductive support by a suitable method such as vacuum deposition, coating of a pigment solution or a resin solution. The charge generation layer is formed as a thin layer by coating a dispersion liquid in which fine particles of the pigment are dispersed, and the charge carriers generated in the charge generation layer can be efficiently injected onto the charge generation layer, and the movement of the charge carrier is performed. The photoconductor has a charge transport layer (generally, the charge transport layer is composed of a charge transport material and a binder resin). Conventionally, as a disazo compound used in this type of photoreceptor, for example, benzidine-based disazo compounds described in JP-A-47-37543 and JP-A-52-55643 or JP-A-52- The stilbene-based disazo compound described in 8832 is known. However,
Laminated photoreceptors using conventional disazo compounds generally have low sensitivity and have a visible wavelength range of about 450 to 7
It extends over 00 nm, and the image reproducibility of the red original is poor due to this photosensitive wavelength characteristic. Therefore, when the photoconductor is mounted, there is a disadvantage in designing the copying machine because it is necessary to use a filter that cuts red light.

OBJECT The object of the present invention is to provide a disazo compound which is effective in an electrophotographic photoreceptor, particularly effective in the above-mentioned laminated photoreceptor, and a laminated photoreceptor using the disazo compound of the present invention. Has a higher sensitivity than a photoconductor using a conventional disazo compound, and its photosensitive wavelength range is only on the short wavelength side of the visible range (about 450 to 600 nm), so the copy image reproducibility of a red original is also excellent. It is a thing.

Structure That is, the present invention is a disazo compound represented by the following general formula (I).

[In the formula, A is (However, R represents an alkyl group, an alkoxy group, a nitro group, a halogen, a cyano group or a halomethyl group, and n is 0,
When n is an integer of 1 or 2 or 3, and n is an integer of 2 or 3, R represents either the same or different groups)] Disazo represented by the formula (I) of the present invention The compound can be produced as follows.

Formula (III) The diamino compound represented by the general formula (I
I) (Wherein X represents an anion functional group), and a tetrazonium salt represented by the general formula (IV), (V) or (VI) (In the formula, R represents an alkyl group, an alkoxy group, a nitro group, a halogen group, a cyano group or a halomethyl group, and n represents
In the case where n is an integer of 0, 1, 2 or 3 and n is an integer of 2 or 3, R may be the same or different group) and the compound represented by the formula (I ) Compound.

Anio in the tetrazonium salt compound of general formula (II)
Cl is a typical example of a functional group. , Br , I ▲ BF
_Four▼, ▲ PF ₆▼ 、▲ AsF ₆▼, ▲ SbF ₆▼, and preferably ▲
BF _Four▼

The disazo compound represented by the formula (I) of the present invention is useful as a charge generating substance for a laminated electrophotographic photoreceptor,
Further, as a charge generating substance in an electrophotographic photoreceptor having a single-layer type photosensitive layer in which a charge generating substance and a charge carrier substance are dispersed in a resin, and a photosensitive layer in which a photoconductive substance is dispersed in a resin It is also useful as a photoconductive substance in an electrophotographic photosensitive member having.

The tetrazonium salt represented by the general formula (II), which is an intermediate of the present invention, is diazotized, for example, after reducing 3,3′-dinitrobenzophenone to 3,3′-diaminobenzophenone. It can be obtained.

The diazotization of 3,3'-diaminobenzophenone is carried out by adding sodium nitrite at -10 ° C to 20 ° C in an inorganic acid such as hydrochloric acid or sulfuric acid. The diazotization reaction is completed in about 30 minutes to 3 hours. Further, a tetrazonium salt can be obtained by adding, for example, borofluoric acid or an aqueous sodium borohydride solution to the diazotization reaction solution.

The production of the disazo compound of the general formula (I) of the present invention can be carried out by allowing the above-mentioned diazotization reaction solution to act on the cuppler as it is. It can also be obtained by isolating a tetrazonium salt by precipitating it as a tetrazonium salt of the general formula (II) by adding hydrofluoric acid or an aqueous solution of sodium borofluoride, and then reacting it with a cupler. it can. Actually, this reaction is carried out by dissolving a tetrazonium salt and a cuppler in an organic solvent such as N, N-dimethylformamide (DMF) or dimethylsulfoxide (DMSO) in a mixed solution.
It is carried out by dropping an aqueous alkaline solution such as an aqueous sodium acetate solution at 10 ° C to 40 ° C. The reaction is completed in about 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 organic solvent, recrystallization method, etc.) to complete the production of the disazo compound.

The novel disazo compound of the present invention is a colored crystal at room temperature, and specific examples thereof are shown in Tables 1 and 2 below together with melting points, elemental analysis values and infrared absorption spectrum data.

Example 1 (Production of tetrazonium salt) 3,3'-diamia in hydrochloric acid consisting of 100 ml of water and 25 ml of concentrated hydrochloric acid
Add 10.4 g of nobenzophenone and heat to about 60 ° C for 1 hour
After heating for a while, cool down to -3 ° C, then add Nitrite
A solution prepared by dissolving 7.32 g of sodium acid salt in 25 ml of water is -3 ° C ~
It was added dropwise at a temperature of 0 ° C. over 30 minutes. Then at the same temperature
After stirring for 30 minutes, 42% hydrofluoric acid was added to this reaction solution.
The precipitated crystals were separated, washed with water and dried to 10.8 g (
54%) bisdiazonium bistetrafluoroborate
To give pale yellow crystals. Infrared absorption spectrum (KBr tablets
The agent method is as shown in Fig. 1, 2280 cm^-1To ▲ N _Two
The absorption band based on ▼ is 1680 cm^-1Absorption based on C = 0
The obi was recognized.

Example 2 (Production of Disazo Compound No. 1) 1.02 g of the tetrazonium salt obtained in Example 1 and 2-hydroxy-3-naphthoic acid anilide as a coupling component 1.
32g (2 times mole of tetrazonium salt) and cooled N, N
-Dissolved in 150 ml of dimethylformamide, a solution of 0.82 g of sodium acetate and 7 ml of water was added dropwise thereto over 5 minutes at a temperature of 5 to 10 ° C, and after cooling was stopped, the mixture was further stirred at room temperature for 3 hours. . Then, the formed precipitate was collected, and 200 ml of N, N-dimethylformamide heated to 80 ° C was used.
Wash 3 times with water, then 2 times with 200 ml of water, 2 mmHg at 80 ℃
After drying under reduced pressure, 1.50 g (yield 78.9%) of the disazo compound of Compound No. 1 in Table 1 was obtained. The appearance of this disazo compound is a reddish orange powder, and the infrared absorption spectrum (KB
The r tablet method) is shown in FIG.

Examples 3 to 10 (Production of Disazo Compound Nos. 2 to 9) In the production of the disazo compound of Compound No. 1 of Example 2, the same method as in Example 2 was used except that the compounds of Table 3 below were used as the coupling component. Compound Nos. 2 to 9 shown in Table 1
Of the disazo compound of

Further, among the disazo compounds of the present invention, infrared absorption spectra of typical ones are shown in FIGS.

Figure 3 ... Compound No. 2 Figure 4 ... Compound No. 3 Figure 5 ... Compound No. 4 Figure 6 ... Compound No. 5 Figure 7 ... Compound No. 6 Figure 8 ... Compound No. 7 9 Figure… Compound No.8 Figure 10… Compound No.9 Effect As described above, the disazo compound of the present invention is effective as a photosensitive material of an electrophotographic photosensitive member, particularly as a charge generating material of a laminated type photosensitive member. Here is an example: Further, in order to clarify the inventive step of the present invention, a comparison with a conventional disazo compound is also shown.

Example of Use In a ball mill, 76 parts by weight of the disazo compound No. 7 of the present invention, 1260 parts by weight of a tetrahydrofuran solution (solid content concentration 2%) of a polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.) and 3700 parts by weight of tetrahydrofuran are placed in a ball mill. The mixture was pulverized and mixed, and the resulting dispersion was applied onto the aluminum surface of an aluminum vapor-deposited polyester base (conductive support) using a doctor blade and naturally dried to form a charge generation layer having a thickness of about 1 μm. . On the other hand, 4'-diphenylamino-
2 parts by weight of α-phenyl-trans-stilbene, 2 parts by weight of a polycarbonate resin (Panlite K1300, Teijin Kasei Co., Ltd.) and 16 parts by weight of tetrahydrofuran were mixed and dissolved to obtain a solution, which was then placed on the charge generation layer. Apply with a doctor blade for 2 minutes at 80 ℃ and then 5 at 100 ℃
Dry for a minute to form a charge transport layer with a thickness of about 20 μm,
A laminated type photoreceptor (A) shown in FIG. 11 was prepared.

For comparison, according to the procedure for preparing the above-mentioned photoreceptor, the above-mentioned JP-A-45-37543 and JP-A-52-5 were used instead of the disazo compound of the present invention.
4,4'-bis (2-hydroxy-3-phenylcarbamoyl-1-naphthylazo) -3,3'-dichlorodiphenyl, which is a benzidine-based disazo compound disclosed in Japanese Patent No. 5643, and In the same manner, except that the stilbene-type disazo compound 4,4'-bis (2-hydroxy-3-phenylcarbamoyl-1-naphthylazo) stilbene described in JP-A-52-8832 was used, each was exposed to light. A body (B) and a photoreceptor (C) were prepared.

The electrostatic characteristics of the photoconductors (A), (B) and (C) thus produced were measured using a commercially available electrostatic copying paper tester (Kawaguchi Denki Seisakusho, SP-428 type). did. That is, first, apply a -6KV corona discharge to the photoreceptor 20 times.
It is negatively charged for 2 seconds, the surface potential at that time is measured, and Vdo (volt) is obtained. Then, dark decay is performed for 20 seconds in a dark place, and the surface potential at that time is measured and measured as Vpo (volt). did. Then, from the tungsten lamp, the photosensitive layer is irradiated with light so that the surface has an illuminance of 20 lux,
The exposure time (second) until the surface potential became 1/2 of Vpo was determined as the exposure amount E1 / 2 (lux · second). Similarly, Vpo
Exposure time E is calculated by finding the time (seconds) until it becomes 1/5 and 1/10
1/5 (lux seconds) and E1 / 10 (lux seconds) were calculated. The results are shown in Table 4.

Further, in order to investigate the photosensitive wavelength range of the photoconductor (A) according to the present invention, the spectral sensitivity was measured by the following measurement procedure.

First, the surface potential of a photoconductor is charged to -800 volts or more by corona discharge in the dark, and the light is attenuated until the surface potential reaches -800 volts. When the surface potential reaches -800 volts, the monochromator is reached. 1μW / cm ^{2 using the}
The monochromatic light of was applied to the photoconductor. Then, the time (seconds) until the surface potential decays to −400 V was obtained, and the half-dose exposure amount (μW · sec / cm ² ) was calculated. On the other hand, the potential difference actually obtained by exposure is calculated by subtracting the potential attenuation due to dark decay from the apparent potential difference of 400 V obtained by exposure, and the light decay rate is calculated from this potential difference and the half-exposure amount. (Volt · cm ² · μW ⁻¹ · sec ⁻¹ ) was calculated as the sensitivity. This spectral sensitivity curve is shown in FIG.

As is clear from the results in Table 4, the photoconductor (A) using the disazo compound of the present invention has extremely high sensitivity as compared with the photoconductors (B) and (C) using the conventional disazo compound. I understand.

Further, from FIG. 12, it is found that the photoconductor (A) using the disazo compound of the present invention has a photosensitive wavelength region of about 450 to 600 nm, which shows that the image reproducibility of a red original is good. Can understand.

[Brief description of drawings]

FIG. 1 is an infrared absorption spectrum diagram (KBr tablet method) of the tetrazonium salt compound of the example. 2 to 10 are infrared absorption spectrum diagrams (KBr tablet method) of representative disazo compounds of the present invention. FIG. 11 is an enlarged cross-sectional view of an electrophotographic photosensitive member according to the present invention, in which 11 is a polyester base, 22 is an aluminum vapor deposition film, 33 is a charge generation layer, and 44 is a charge transport layer. FIG. 12 is a spectral sensitivity curve of the electrophotographic photosensitive member according to the present invention.

Claims (1)

[Claims] 1. A general formula (I) [In the formula, A is (However, R represents an alkyl group, an alkoxy group, a nitro group, a halogen, a cyano group or a halomethyl group, and n is 0,
And R is an integer of 1, 2 or 3 and n is an integer of 2 or 3, R may represent the same or different groups)].