JPH02284149A - electrophotographic photoreceptor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

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

CB) Prior art and problems Conventionally, inorganic photoconductive materials such as selenium, cadmium sulfide, ram, zinc oxide, silicon, etc. have been known to be used as electrophotographic photoreceptors, and have been extensively studied and put into practical use. has been made into In recent years, in contrast to these S-based materials, research into organic photoconductive materials has progressed actively, and some have been put into practical use as electrophotographic photoreceptors.

Generally speaking, inorganic materials have problems such as thermal stability, deterioration of properties due to crystallization, and manufacturing difficulties in selenium photoreceptors, and moisture resistance, durability, and industrial difficulties in the case of cadmium sulfide. Compared to the current situation, which is not always satisfactory due to problems such as waste disposal, organic materials have good film-forming properties, excellent combustibility, are lightweight, and have excellent transparency. Its practical application is increasingly attracting attention because it has advantages such as easy design of photoreceptors for a wide range of wavelengths using a suitable sensitization method.

By the way, the photoreceptor used in electrophotography technology is -
The following basic numerical properties are required.

That is, (1) it has a high chargeability against corona discharge in a dark place, (2) there is little leakage (dark decay) of the obtained charged charge in a dark place, and (3) it has a high charging property with respect to corona discharge in a dark place. ! !
(4) The charge dissipation (light attenuation) is rapid, and (4) the residual charge after light irradiation is small.

However, to date, much research has been conducted on photoconductive polymers such as polyvinylcarbazole as organic photoconductive substances, but these do not necessarily have sufficient film properties, scorbability, or adhesive properties, and as mentioned above, It is difficult to say that the photoconductor has sufficient basic properties as a photoreceptor.

On the other hand, since organic low-molecular photoconductive compounds generally do not have film-forming ability, it is necessary to use an appropriate binder in combination. Although this removal of the binder is advantageous in that the physical properties and electrophotographic properties of the film can be controlled to some extent, the types of organic photoconductive compounds that have high compatibility with the binder are limited, and Currently, there are not many that have been put into practical use.

(C) Purpose of the Invention As stated above, various improvements have been made in the production of electrophotographic photoreceptors, but none that satisfy the basic properties and high durability required for photoreceptors listed above. I haven't gotten anything yet.

An object of the present invention is to provide an electrophotographic photoreceptor containing an organic photoconductive compound that has excellent compatibility with a binder, is stable against heat and light, and has an excellent carrier transport ability.

Another object of the present invention is to provide an electrophotographic photoreceptor with high sensitivity and low residual potential.

Another object of the present invention is to provide a photoreceptor that has high charging characteristics, exhibits almost no decrease in sensitivity even after repeated use, and has a stable band ti position.

CD) Structure of the Invention The above objects are achieved by providing a photosensitive layer containing a hydrazone compound represented by the following general formula CI) on a conductive support.

(In the formula, R1 and R2 represent an optionally substituted alkyl group, alkenyl group, aralkyl group, aryl group, or bicyclic ring, and R5 and R4 are a hydrogen atom, an alkyl group, an alkoxy group, or a halogen Represents an atom.Z
represents an atomic group necessary to form a tetrahydroquinoline ring or an indoline ring together with a nitrogen atom. ) Specific examples of the substituents 1 and R2 include alkyl groups such as methyl, ethyl, propyl, and isopropyl; alkenyl groups such as allyl, methallyl, chloride, and cinnamyl; and benzyl. , aralkyl groups such as β-phenylethyl group, chlorobenzyl group, methoxybenzyl group, α-naphthylmethyl group, phenyl group, aryl group such as tri/L4, methoxyphenyl group, chlorophenyl group, pyridyl group, thiazolyl group, benzothiazolyl group Examples include heterocyclic groups such as groups.

Specific examples of substituents R3 and R4 include hydrogen atoms, alkyl groups such as methyl, ethyl, propyl, and isopropyl groups, alkoxy groups such as methoxy, ethoxy, propoxy, and impropoxy groups, and chlorine atoms. ,
Examples include halogen atoms such as bromine atoms and iodine atoms.

These hydrazone compounds represented by the general formula CI) are produced by the method in the following synthesis example.

Synthesis Example 1 (Exemplary Compound (1)) HO Dialdehyde (1,45F) represented by formula ■, methylphenylhydrazine (1,44f), ethanol (10
Acetic acid (0.1 ml) was added to the solution of 1 ml of the mixture, and the mixture was refluxed for 2 hours. After cooling to room temperature, the precipitate was separated and recrystallized from a mixed solvent of ethanol and dioxane (8:2) to obtain the exemplified compound (11't-1,29. Yield: 51 cm, melting point: 190 .1 to 191.2°C Synthesis Example (Exemplary Compound (24)) However, it is not limited to these.

Dialdehyde (0,93f) shown in 2■, methylphenylhydrazine (0,9(1), ethanol, (10
Acetic acid (0.1 m) was added to the solution of ffi7, and the mixture was refluxed for 2 hours. After cooling to room temperature, the precipitate t-F was collected and recrystallized from benzene to obtain exemplified compound (24) at 1.01? Obtained. Yield: 59°C, melting point: 211.7-212.7°C Next, hydrazone compounds according to the present invention are exemplified. It is obtained by containing and has excellent performance.

Various methods are known for using these hydrazone compounds as electrophotographic photoreceptors.

For example, a photosensitive material prepared by dissolving or dispersing a hydrazone compound and a sensitizing dye in a binder resin, with the addition of a chemical sensitizer or an electron-withdrawing compound as necessary, on a conductive support. on a conductive support in the form of a body or a laminated structure consisting of a carrier generation layer and a carrier transport layer,
A chemical sensitizer or an electron-withdrawing compound may be added to the present hydrazone compound as a binder on a carrier-generating layer mainly composed of a carrier-generating substance with high carrier-generating efficiency, such as a dye or a pigment. There are photoreceptors formed by laminating a carrier transport layer dissolved or dispersed in a resin, and photoreceptors formed by laminating the carrier generation layer and carrier transport layer inversely on a conductive support. , can be applied in either case.

As a support for producing a photoreceptor using the compound of the present invention, a metal drum, a metal plate, paper treated with electrical conductivity, a plastic film, or a belt-like support is 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.

The amount of these binder resins added to the photoconductive compound is 0.2 to 10 times the weight of the photoconductive compound.

Preferably, the amount is in the range of 0.5 to 5 times; if the amount is less than this, the photoconductive compound will precipitate in the photosensitive layer or on the surface, resulting in poor adhesion to the support, and if it is too much, the sensitivity will decrease.

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 phthalate esters (e.g.
(OP, DBP, DIDP, etc.) IJ n'flx esters (eg, TCP, TOP, etc.), sepacic acid esters, adipic acid esters, nitrile rubber, chlorinated hydrocarbons, and the like. When adding these plasticity-providing substances, adding more than necessary will cause deterioration of potential characteristics, so the proportion should be 2C)% by weight relative to the binder resin.
The following are preferred.

Next, the sensitizing dye added to the photosensitive layer is 71,
% Erythrosine, a triphenylmethane dye represented by Le Violet, Crystal Violet, Ethyl Violet, Night Blue, Victoria Blue, etc.
Xanthen dyes represented by Rhodamine B, Rhodamine 3B, Acridine Red B, etc., Acridine Orange 2
G, 7ri IJ Acridine dyes such as thin orange dye and flabeosin, methylene blue, thiazine dyes such as methylene greente, fog blue,
Other examples include oxazine dyes such as Melt Lab, cyanine dyes, styryl dyes, pyrylium salts, thiapyrylium salts, and squareium salt dyes.

In addition, metal-free 7 is a photoconductive pigment that generates carriers with extremely high efficiency through light absorption in the photosensitive layer.
Phthalocyanine I materials, such as talocyanine, phthalocyanine containing various metals or metallizations;
Examples include perylene pigments such as L/Nimito and perylenic anhydride, as well as quinacridone pigments, anthraquinone pigments, and azo pigments.

Among these pigments, those using bisazo pigments, trisazo pigments, and phthalocyanine pigments, which have particularly high carrier generation efficiency, provide high sensitivity and provide excellent electronic photoreceptors.

Furthermore, although the aforementioned dye added to the photosensitive layer can be used alone as a carrier-generating substance, carriers may be generated with even higher efficiency by coexisting with a pigment. Further inorganic photoconductive materials include selenium, selenium tellurium alloy, cadmium sulfide, zinc sulfide, amorphous silicon, and the like.

In addition to the sensitizers mentioned above (so-called spectral sensitizers), it is also possible to add sensitizers (so-called chemical sensitizers) for the purpose of improving sensitivity.

Examples of the sensitizer include p-chlorophenol, m-chlorophenol, p-nitrophenol, 4-chloro-
m-Cresol, p-chlorobenzoylacetanilide, N,N/-diethylbarbital acid, 3-(β-oxyethyl)-2-7 enyliminothiazolidone, malonic acid dianilide, 3.5.3 ', 5'-tetrachloromalonic acid dianilide, α-su7tol, p-nitrobenzoic acid, and the like.

Further, it is also possible to add a certain type of electron-withdrawing compound as a sensitizer that forms a charge transfer complex with the hydrazone compound of the present invention and further increases the sensitizing effect.

Examples of the electron-withdrawing substance include 1-chloroanthraquinone, 1-nitroanthraquinone, 2,3-dichloro-naphthoquinone, 3,3-dinitrobenzophenone,
4-nitrobenzalmalonenitrile, phthalic anhydride, 3
-(α-cyano-p-nitrobenzal)phthalide, 2,
4.7-) IJ nitrofluorenone, 1-methyl-
4-nitrofluorenone, 2,7-sinitro 3,6-
Examples include dimethylfluorenone.

Other additives such as antioxidants and anti-curl agents may be added to the photoreceptor as required.

The hydrazone compound of the present invention is dissolved or dispersed in an appropriate solvent together with the various additive substances mentioned above depending on the form of the photoreceptor, and the coating solution is applied onto the conductive support described above.
Dry to produce a photoreceptor.

Examples of coating solvents include halogenated hydrocarbons such as chloroform, dichloroethane, trichloroethane, and trichloroethylene, aromatic hydrocarbons such as benzene, toluene, xylene, and monochlorobenzene, dioxane, tetrahydro7rane, methylcellosolve, dimethylcellosolve,
Solvents such as methyl cellosolve acetate alone or in combination
A mixed solvent of more than one species may be used, or a solvent such as alcohol, acetonitrile, N,N-dimethylformamide, methyl ethyl ketone, etc. may be further added as necessary.

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 the pigment shown in Example 1, 1 part by weight of polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.), and 1 part by weight of Tetrahythm 07 Run 1
00 parts by weight, and dispersed with glass beads for 2 hours using a paint conditioner. The pigment dispersion thus obtained was applied onto a polyester film deposited with aluminum using an applicator and dried to form a film of the carrier-generating substance having a thickness of about 0.2 μm.

Next, a hydrazone compound represented by Exemplary Compound A1 was mixed with a polyarylate resin (U-polymer manufactured by Unitika) in a 1:1 ratio.
Mix with a Mi ratio of 10% using dichloroethane as a solvent.
A solution was prepared, and this solution was applied onto the film of the carrier-generating substance using an applicator to form a carrier transport layer with a dry film thickness of 20 μm.

The electrophotographic properties of the thus-prepared mounded layer type electrophotographic photoreceptor were evaluated using an electrostatic recording tester (SP~428 manufactured by Kawaguchi Denki).

Measurement conditions: applied voltage -6 mushrooms, static A3°.As a result, the half-light exposure amount to white light during charging was 2.8 lux·sec, a value of very high sensitivity.

Furthermore, the same device was used to evaluate repeated use.

When the change in charging potential due to 103 repetitions was calculated, 1
In contrast to the initial potential of 770 V in the 103rd test, the initial potential in the 103rd test was 750 V, and it was found that the potential decreased little due to repetition and was stable, showing excellent characteristics. Also,
When the surface of this photoreceptor was observed, no crystal precipitation due to poor compatibility with the binder was observed, and it was in good condition.

Comparative Example 1 A laminated photoreceptor was prepared in the same manner as in Example 1, except that the following comparative compound (1) was used in place of the hydrazone compound used in Example 1. After drying, countless microcrystals were deposited on the surface of this photoreceptor.

Examples 2 to 5 Laminated photoreceptors were prepared in the same manner as in Example 1, except that the hydrazone compounds shown in Table 1 were used in place of the hydrazone compounds used in Example 1, and the same measurement conditions as in Example 1 were carried out. The half-light exposure time El/2 (lux ◆ seconds) and the initial potential Vo (volts) were measured, and the values are shown in Table 1. Furthermore, after performing the same green reversal 103 times with one cycle of charging and static neutralization (static neutralization light: 400 lux x 1 second irradiation with white light), the initial potential Vo (volt) and the light half-reduced exposure amount E 1
/2 is shown in Table 1.

Table 1 Examples 6 to 9 A bisazo pigment having the following structure was used as a charge generating material to form a carrier generating layer. The thickness of this thin film was about 0.2μ.

Next, Example 1 was prepared using the exemplified compounds shown in Table 2.
A carrier transport rm was formed in the same manner as above to create a laminated photoreceptor. This photoreceptor was evaluated under the same measurement conditions as in Example 1.

The results are shown in Table 2.

Table 2 was used. That is, 1 part by weight of this pigment, 1 part by weight of a polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) were mixed with 100 parts by weight of tetrahydrofuran, and the mixture was dispersed with glass peas for 2 hours using a paint conditioner. Comparative Example 2 The pigment dispersion thus obtained was applied onto the same support as in Example 1 using an applicator. Examples 6-9
A laminated photoreceptor was prepared in the same manner as above. When the electrophotographic characteristics of this photoreceptor were measured, the first initial potential of 700V was 103
In the second time, it decreased to 5 sov.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor comprising a hydrazone compound represented by the following general formula (I) on a conductive support. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) (In the formula, R^1 and R^2 are optionally substituted alkyl groups, alkenyl groups, aralkyl groups, aryl groups,
or represents a heterocyclic group, and R^3 and R^4 represent a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom. Z represents an atomic group necessary to form a tetrahydroquinoline ring or an indoline ring together with a nitrogen atom. )