JPH03179358A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body having a high sensitivity and high durability by incorporating a specific bisazo compd. into this body. CONSTITUTION:The bisazo compd. expressed by formula I is used. In the formu la I, R<1> to R<4> denote a hydrogen atom, halogen atom, etc.; Ar<1>, Ar<2> denote an arylene group; (m) denotes 0, 1; A denotes an aryl group having a hydroxyl group, heterocyclic group. The photosensitive layer consisting of the bisazo compd., charge transfer material and film formable binder resin, etc., is provided on a conductive base. The electrophotographic sensitive body having the high sensitivity and high durability is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to an electrophotographic photoreceptor characterized by containing a novel bisazo compound.

(B) Prior art and problems Conventionally, inorganic photoconductive materials such as selenium, cadmium sulfide, zinc oxide, and silicon have been known to be used as electrophotographic photoreceptors, and have been widely studied and put into practical use. has been done. Although these inorganic materials have many advantages, they also have various disadvantages. For example, selenium has the disadvantage of difficult manufacturing conditions and is easily crystallized by heat or mechanical shock, while cadmium sulfide and zinc oxide have poor moisture resistance and durability. Regarding silicon, it has been pointed out that it lacks chargeability and is difficult to manufacture. Furthermore, selenium and cadmium sulfide have toxicity issues, whereas organic photoconductive materials have good film-forming properties, excellent flexibility, light weight, good transparency, and can be used with appropriate enhancement. The practical use of this method is gradually attracting attention because it has advantages such as the ease of designing a photoreceptor for a wide range of wavelengths.

Incidentally, photoreceptors used in electrophotography are generally required to have the following basic properties.

That is, (1) the charging property is high against corona discharge in the dark, (2) there is little leakage (dark decay) of the obtained charged charge in the dark, and (3) the charged charge is reduced by light irradiation. (4) The residual charge after light irradiation is small.

However, to date, much research has been conducted on photoconductive polymers such as borylvinylcarbazole as organic photoconductive substances, but these do not necessarily have sufficient film properties, flexibility, or adhesive properties. It cannot be said that the above-mentioned basic properties as a photoreceptor are sufficiently provided.

On the other hand, with regard to organic low-molecular photoconductive compounds, it is possible to obtain photoreceptors with excellent film properties, adhesion, flexibility, and other mechanical strengths by selecting the binder used to form the photoreceptor. Although possible, it is difficult to find a compound that can retain high sensitivity properties.

In order to improve this point, an organic photoreceptor having higher sensitivity has been developed by assigning the carrier generation function and the carrier transport function to different substances. A feature of such a photoreceptor, which is called a functionally separated type, is that materials for each function can be selected from a wide range, and a photoreceptor with arbitrary performance can be easily created, which has led to a lot of research. has been progressing.

(C) Purpose of the Invention As mentioned above, various improvements have been made in the production of electrophotographic photoreceptors, but the basic properties and high durability required for photoreceptors as mentioned above have not been met. I still haven't been able to find enough to satisfy my needs.

The purpose of the present invention is to have high sensitivity, high durability, high charging characteristics, and almost no decrease in sensitivity even after repeated use.
An object of the present invention is to provide an electrophotographic photoreceptor with stable charging potential.

(D) Structure of the Invention As a result of research into photoconductive substances with high sensitivity and high durability, the present inventors found that a novel bisazo compound represented by the following general formula (I) is effective. This heading led to the present invention.

(In the formula This represents an arylene group that may be present. m represents O or 1, and A represents an aryl group or a heterocyclic group having a hydroxyl group. Two A's may be the same or different.) Here, specific examples of R1-R4 include hydrogen atoms, halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms, alkyl groups such as cyano groups, methyl groups, ethyl groups, and propyl groups, benzyl groups, methylbenzyl groups, and chloro benzyl group, β-
Examples include aralkyl groups such as phenylethyl group and α-naphthylmethyl group, and aryl groups such as phenyl group, methoxyphenyl group, methylphenyl group, chlorophenyl group, and naphthyl group. Specific examples of Ar' and Ar' include arylene groups such as phenylene group, methoxyphenylene group, methylphenylene group, chlorophenylene group, and naphthylene group.

Specific examples of A include the compounds shown below.

(The following is a blank space) 321 22 23 25 26 -327 H υH N=l'1 1 2 -13 -14 6 N=N-A -2l N=N-^ -23 B 8 I -30 Combination example (Illustrated compound B-2, synthesis of A=A-161)) 3-(p-nitrophenyl)-1-phenyl-2,3-
The dinitro compound (7.1 g) obtained by combining epoxy-1-propanone and p-nitrophenylhydrazine was reduced using iron powder to synthesize the following diamino compound (2.7 g).

Melting point 197.2-198.0°C NMR (δ, ppm, DMSO) 5.31 (S, 2H, NO3'), 5.33
(8,2H1NH2), 6.49 (d, J=8.4
Hz.

2H), 6.56 (dX J=8.7Hz, 2
H), 6.6 (s, IH), 6.98-6.92
(m.

4H), 7.31-7.33 (m, IH), 7
゜39-7.44 (m, 2H), 7.85 (
d, J = 8.4Hz, 2H) The above diamino compound (0.33g) was dissolved in DMF (15ml) and 2N hydrochloric acid (0.22ml), and an aqueous solution of sodium nitrite (0.15g) was added at about 5°C. (0.5 ml) was added. After 30 minutes, 42% fluoroboric acid (4 ml)
was added, and the precipitated tetrazonium salt was collected by filtration. Dissolve this and A-161 (0°80 g) in DMF (50 ml) and add an aqueous solution (3 ml) of sodium acetate (0.66 g).
1) was added dropwise at 5 to 10°C over 5 minutes. After stirring at the same temperature for 2 hours and further at room temperature for 2 hours, the precipitate was collected by filtration and washed with DMF, acetone, and 100 ml of water.

Yield: 0.58 g Yield: 50% Melting point: 270° C. or higher The electrophotographic photoreceptor of the present invention is obtained by containing one or more bisazo compounds represented by the general formula (I). Various types of photoreceptors are known, and any of them can be used. For example, there is one in which a photosensitive layer comprising a bisazo compound, a known charge transport substance, and a film-forming binder resin is provided on a conductive support. Also known is a laminated photoreceptor in which a charge generation layer made of a bisazo compound and a binder resin and a charge transport layer made of a charge transport substance and a binder resin are provided on a conductive support. Either the charge generation layer or the charge transport layer may be the upper layer.

As the support for producing the photoreceptor using the compound of the present invention, metal drums, metal plates, conductive treated paper, sheet-like, drum-like, or belt-like supports of plastic films are used. .

Various film-forming binder resins can be used to form the photosensitive layer on these supports depending on the field of use. For example, for use in photoreceptors for copying, polystyrene resin, polyvinyl acetal resin, polysulfone resin, polycarbonate resin, vinyl acetate/crotonic acid copolymer resin, polyphenylene oxide resin, polyester resin, alkyd resin, polyarylate resin, acrylic resin, methacrylic resin , phenoxy resin, etc. Among these, polystyrene resins, polyvinyl acetal resins, polycarbonate resins, polyester resins, polyarylate resins, phenol resins, and the like have excellent potential characteristics as photoreceptors.

In addition, these resins may be used alone or as a copolymer.
A mixture of more than one species can be used.

Next, some of the film-forming binder resins used are rigid and weak in mechanical strength such as tension, bending, and compression, so it is necessary to add a substance that imparts plasticity to improve these properties. Become.

These substances include phthalates (e.g. DO
P, DBP, DIOP, etc.), phosphoric acid esters (eg, TCP, TOP, etc.), sebacic acid esters, adipic acid esters, nitrile rubber, chlorinated hydrocarbons, and the like. When adding these plasticity imparting substances,
Since adding more than necessary will cause deterioration of potential characteristics, the proportion thereof is preferably 20% or less by weight based on the binder resin.

Antioxidants, anti-curl agents, and the like can be added as additives to the low photoreceptor, if necessary.

Charge transport materials include hole transport materials and electron transport materials.

Examples of the former include oxadiazoles shown in Japanese Patent Publication No. 34-5466, Japanese Patent Publication No. 45-55
Triphenylmethanes shown in Japanese Patent Publication No. 52-4188, hydrazones shown in Japanese Patent Publication No. 55-42380, JP-A-56-123544. Oxazoles shown in Japanese Patent Publication No. 58-32372, triarylamines shown in Japanese Patent Publication No. 58-19804
Examples include stilbenes shown in Publication No. 3. On the other hand, examples of electron transport substances include chloranil, tetracyanoethylene, 2.4.7-dolinitro-9-fluorenone, 2.4.5.7-titranitroxanthone, 1.3.7-)linitrogibezothio Examples include fen. These charge transport materials can be used alone or in combination of two or more.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 1 part by weight of Exemplified Compound B-2 (A=A-161) and 1 part by weight of polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) were mixed with 100 parts by weight of tetrahydrofuran, and dispersed together with glass peas in a paint conditioner device for 2 hours. . The thus obtained dispersion was applied onto aluminum-deposited polyester using an applicator to form a charge generation layer having a thickness of 0.2 μm. Next, p-dibenzylaminobenzaldehyde-diphenylhydrazone was mixed with a polyarylate resin (Unitika U-polymer) at a weight ratio of 1=1 to make a 10% solution using dichloroethane as a solvent.
A charge transport layer having a thickness of about 20 μm was formed by applying the charge transport layer onto the above charge generation layer using an applicator.

The laminated photoconductor created in this way was tested on electrostatic recording paper! (5P-428 manufactured by Kawaguchi Electric) was used to evaluate the electrophotographic characteristics.

Measurement conditions: applied voltage -6 kv, static N113°.As a result, the half-decrease exposure amount was 2.5 lux·sec, which was a very high sensitivity value.

Furthermore, the same device was used to evaluate repeated use1.
When we calculated the change in the charged potential due to repetition at 03 times, we found that the initial potential at the 103rd time was 950 V compared to the initial potential of 970 V at the 1st time, and it was found that the potential decrease due to repetition was small and stable. It showed excellent properties.

Examples 2 to 5 Laminated photoreceptors were prepared in the same manner as in Example 1, except that the bisazo compounds shown in Table 1 were used in place of the bisazo compounds used in Example 1, and measurements were carried out in the same manner as in Example 1. Under the conditions, the optical half-reduced exposure amount El/2 (lux seconds) and the initial potential Vo (volts) were measured, and the values are shown in Table 1.

Furthermore, after repeating the same process 103 times with one cycle of charging and neutralization (static discharge: 400 lux x 1 second irradiation with white light), the initial potential Vo (volt) and the light half-reduced exposure amount E1
/2 was determined and the results are shown in Table 1.

(Margins below) Table *: (lux seconds) Comparative Example 1.2 A photoreceptor was prepared in the same manner as in Example 1, except that Comparative Compound 1.2 below was used in place of the compound used in Example 1. and evaluated its characteristics. The results are shown in Table 2.

Comparative Compound 1 Comparative Compound 2 (blank below) Table *: (lux seconds) Examples 6 to 9 Examples except that the bisazo compound shown in Table 3 was used in place of the bisazo compound used in Example 1. A charge generation layer was formed in the same manner as in Example 1.

Next, 1-phenyl-5-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline and polyester resin (Vylon-2O0) were mixed at a weight ratio of (:1), and dichloroethane was used as a solvent to make a 10% A solution was prepared and applied onto the above charge generation layer using an applicator to form a charge transport layer having a film thickness of about 20μ.

The electrophotographic properties of the laminated photoreceptor thus produced were determined in the same manner as in Example 1. The results are shown in Table 3.

(The following is a blank space) Table *: (lux seconds) (E) Effects of the Invention As is clear from the above, according to the present invention, an electrophotographic photoreceptor having high sensitivity and high durability can be provided.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor containing a bisazo compound represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In formula (I), R^1 to R^4 are hydrogen atoms, halogen atoms, cyano groups, alkyl groups that may have substituents, aralkyl groups, aryl group, Ar^1 and Ar^2 represent an arylene group which may have a substituent. m represents 0 or 1, and A represents an aryl group or a heterocyclic group having a hydroxyl group. Two A may be the same or different.)