JPH0554509B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a novel disazo compound and a method for producing the same. Prior Art It has been known that certain disazo compounds are effective as charge-generating pigments used in charge-generating layers of laminated electrophotographic photoreceptors. 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 evaporation, coating of a pigment solution, or addition of a pigment to a resin solution. A charge-generating layer is formed as a thin layer by coating a dispersion liquid containing fine particles, and a charge-transporting layer is formed on the charge-generating layer into which the charge carriers generated in the charge-generating layer can be efficiently injected and also move. (This charge transport layer usually consists of a charge transport substance and a binder resin). Until now, as disazo compounds used in this type of photoreceptor, for example, benzidine-based disazo compounds described in publications such as JP-A-47-37543 and JP-A-52-55643; Stilbene-based disazo compounds described in JP-A-52-8832 are known. However, conventional laminated photoreceptors using disazo compounds generally have low sensitivity, and the photosensitive wavelength range in the visible range extends from approximately 450 to 700 nm. It was a bad idea. Therefore, when this photoreceptor is mounted, there is a disadvantage in the design of the copying machine because it is necessary to use a filter that cuts out red light. Purpose An object of the present invention is to provide a novel disazo compound that is effective in electrophotographic photoreceptors, particularly in the above-mentioned laminated electrophotographic photoreceptor. Another object of the present invention is to provide a method for producing the above-mentioned disazo compound. That is, one of the present inventions is the following general formula () [However, A is or

A coupler residue represented by the formula (where, represents a phenyl group substituted with
R ¹ , R ² and R ³ represent hydrogen or a lower alkyl group). ] This is a novel disazo compound represented by Specific examples of X in the general formula () include a benzene ring, a naphthalene ring, and a carbazole ring. Another aspect of the present invention is the formula () By diazotizing 3,6-bis(4-aminophenyl)-s-tetrazine represented by the general formula () (In the formula, Y represents an anionic functional group.) A general formula () characterized in that the tetrazonium salt is reacted with a coupler having a coupler residue represented by A above. (In the formula, A represents the same coupler residue as above.) This is a method for producing a novel disazo compound represented by the following formula. In this production method, 3,6-bis(4-aminophenyl)-s-tetrazine is diazotized by diazotizing it with sodium nitrite in an inorganic acid such as hydrochloric acid or sulfuric acid at -10°C to 50°C. This is done by adding at. This diazotization reaction is completed in approximately 30 minutes to 3 hours. Furthermore, it is preferable to add, for example, hydroborofluoric acid or an aqueous sodium borofluoride solution to the reaction mixture to precipitate the tetrazonium salt, and then use it in the next reaction after crystallizing it. Next, this tetrazonium salt is reacted with the coupler represented by A above to cause a coupling reaction. In reality, this reaction is performed using N,N-dimethylformamide (DMF)
A tetrazonium salt and a coupler are mixed and dissolved in an organic solvent such as dimethyl sulfoxide or dimethyl sulfoxide, and an alkaline aqueous solution such as a sodium acetate aqueous solution is added dropwise to the mixture at about -10°C to 40°C. This reaction is complete in approximately 5 minutes to 3 hours. After the reaction is completed, 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 disazo compound. Examples of the production of the disazo compound of the present invention produced in this manner are as follows. Production example: 3,6 into hydrochloric acid consisting of 79 ml of water and 79 ml of concentrated hydrochloric acid.
-bis(4-aminophenyl)-s-tetrazine
Add 22.8g and heat at about 60℃ for 1 hour, then -3℃
and then add sodium nitrite to this
A solution of 13.1 g dissolved in 30 ml of water was added dropwise over 50 minutes at a temperature of -3°C to 0°C. Then at the same temperature
After stirring for 30 minutes, 120 ml of 42% borofluoric acid was added to the reaction solution, and the precipitated crystals were separated, washed with water, and dried to obtain 31.38 g (yield 78.8%) of tetrazonium difluoroborate. Red crystals were obtained. The decomposition point was 106°C or higher, and an absorption band based on N ₂ was observed at 2280 cm ^-1 in the infrared absorption spectrum (KBr tablet method). Tetrazonium salt thus obtained 4.6
g and 2-hydroxy-3 as a coupling component.
- Dissolve 5.8 g of naphthoic acid anilide (twice the mole of the tetrazonium salt) in 700 ml of cooled N,N-dimethylformamide, and add a solution consisting of 2.5 g of sodium acetate and 25 ml of water at a temperature of 5 to 10°C. After dropping for 20 minutes and stopping cooling, the precipitate formed was collected and heated to 80°C with N,
Wash 3 times with 700 ml of N-dimethylformamide,
Next, the disazo pigment of Compound No. 1 in Table 1 was washed twice with 700 ml of water and dried at 80°C under a reduced pressure of 2 mmHg.
5.6g (yield 68.9%) was obtained. Tables 1 and 2 show examples of the disazo compounds of the present invention synthesized according to the above production examples.

【table】

【table】

[Table] These new disazo compounds are red to reddish-purple powders at room temperature. 1 to 12 show infrared absorption spectra (KBr tablet method) of typical disazo compounds of the present invention. Figure 1: Compound No. 1 Figure 2: Compound No. 2 Figure 3: Compound No. 3 Figure 4: Compound No. 4 Figure 5: Compound No. 5 Figure 6: Compound No. 10 Figure 7 Figure...Compound No.12 Figure 8...Compound No.13 Figure 9...Compound
No.16 Figure 10...Compound No.19 Figure 11...Compound
No. 21 Figure 12... Compound No. 24 As mentioned above, the disazo compound of the present invention is effective as a photosensitive material for electrophotographic photoreceptors, especially as a charge-generating material for laminated photoreceptors, and this point has been clearly demonstrated. In order to do so, specific usage examples are shown below.
Furthermore, in order to clarify the inventive step of the present invention, a comparison with conventional disazo compounds is also shown. Application example 76 parts by weight of disazo compound No. 12 of the present invention, 1260 parts by weight of a tetrahydrofuran solution (solid content concentration 2%) of polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) and 3700 parts by weight of tetrahydrofuran were ground and mixed in a ball mill. The resulting dispersion was applied using a doctor blade onto the aluminum surface of an aluminum-deposited polyester base (conductive support) and air-dried to form a charge generation layer with a thickness of approximately 1 μm. On the other hand, 2 parts by weight of 9-ethylcarbazole-3-aldehyde-1-methyl-1-phenylhydrazone, 2 parts by weight of polycarbonate resin (Panlite K1300 manufactured by Teijin Chemicals), and tetrahydrofuran.
After mixing and dissolving 16 parts by weight to form a solution, this was applied onto the charge generation layer using a doctor blade.
The mixture was dried at 100° C. for 2 minutes and then for 5 minutes at 100° C. to form a charge transport layer with a thickness of about 20 μm, thereby producing the laminated photoreceptor (A) shown in FIG. For comparison, following the steps for making the photoreceptor above,
Instead of the disazo compound of the present invention, 4,4'-bis(2-
Hydroxy-3-phenylcarbamoyl-1-
naphthylazo)-3,3'-dichlorodiphenyl,
and 4,4'-bis(2-hydroxy-3-phenylcarbamoyl-1-naphthylazo)stilbene, which is a stilbene-based disazo compound described in JP-A-52-8832, was used. and each photoreceptor
(B) and photoreceptor (C) were prepared. Photoreceptors (A), (B) and (C) created in this way
The electrostatic properties of the sample were measured using a commercially available electrostatic copying paper testing device (Model SP-428 manufactured by Kawaguchi Electric Seisakusho Co., Ltd.). That is, first, the photoreceptor is negatively charged by applying a -6KV corona discharge for 20 seconds, and the surface potential at that time is measured to determine Vdo (volts).Then, the surface potential at that time is determined by dark decaying in a dark place for 20 seconds. was measured and defined as Vpo (volts). Next, the photosensitive layer is irradiated with light from a tungsten lamp so that the surface has an illuminance of 4.5 lux, and the time (seconds) until the surface potential becomes 1/2 of Vpo is determined, and the exposure amount E1/2 is determined.
(Lutux seconds). Similarly, find the time (seconds) until it becomes 1/5 and 1/10 of Vpo, and calculate the exposure amount E1/5.
(lux/second) and E1/10 (lux/second) were determined. The results are shown in Table-3.

[Table] As is clear from the results in Table 3, the photoreceptor (A) using the disazo compound of the present invention has higher sensitivity than the photoreceptors (B) and (C) using the conventional disazo compound. It turns out that it is expensive. Effects From what has been described above, it is understood that the disazo compound of the present invention is an extremely effective material. That is, the photoreceptor using the disazo compound of the present invention has high sensitivity, and since its photoreceptor wavelength range is on the short wavelength side of the visible range (approximately 450 to 600 nm), it also has excellent reproduction of reproduced images of red originals. It is becoming. Further, the disazo compound of the present invention can be used 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 transporting substance are dispersed in the resin, and also as a photoconductive substance in the resin. It is also useful as a photoconductive material in an electrophotographic photoreceptor having a photosensitive layer in which a substance is dispersed.

[Brief explanation of drawings]

1 to 12 are infrared absorption spectra (KBr tablet method) of typical disazo compounds of the present invention, and FIG. 13 is an enlarged sectional view of an example of an electrophotographic photoreceptor according to the present invention. 11...Support (polyester base), 22...
Aluminum vapor deposited film, 33... Charge generation layer, 44...
Charge transport layer.

Claims (1)

[Claims] 1 General formula () [However, A is or a coupler residue represented by the formula (where, represents a phenyl group substituted with a group,
R ¹ , R ² and R ³ represent hydrogen or a lower alkyl group). ] A disazo compound represented by 2 formula () By diazotizing 3,6-bis(4-aminophenyl)-s-tetrazine represented by the general formula () (In the formula, Y represents an anionic functional group.) A general formula () characterized by reacting this tetrazonium salt with a coupler having a coupler residue represented by A below. [However, A is or a coupler residue represented by the formula (where, represents a phenyl group substituted with a group,
R ¹ , R ² and R ³ represent hydrogen or a lower alkyl group). ] A method for producing a disazo compound represented by: