JPH01159657A - 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 cA) Industrial Application Field The present invention relates to an electrophotographic photoreceptor, and more specifically, a photoreceptor containing a novel benzhydryl azomethine compound in a photosensitive layer formed on a conductive support. This invention relates to an electrophotographic photoreceptor.

More specifically, the present invention relates to a highly durable electrophotographic photoreceptor with high sensitivity, high charging ability, and excellent repeat stability.

CB) Prior Art Conventionally, inorganic materials such as selenium, cadmium sulfide, amorphous silicon, and zinc oxide have been widely used in the photosensitive layer of electrophotographic photoreceptors in electrophotographic technology.
In recent years, much research has been conducted on the use of organic photoconductive materials as electrophotographic photoreceptors.

Here, the basic properties required for an electrophotographic photoreceptor are: (1) High chargeability due to corona discharge in a dark place 6 (2) Charge due to the obtained corona charge in a dark place Less attenuation. (3) Charges are quickly dissipated by light irradiation. (4) There is little residual charge after irradiation with light. etc.

Conventional inorganic electrophotographic photoreceptors such as selenium and cadmium sulfide have basic properties that meet the requirements for photoreceptors, but they have manufacturing problems such as high toxicity and difficult film formation. However, in the future, it has disadvantages such as lack of flexibility and high manufacturing cost.
The use of photoreceptors from inorganic materials to organic materials is desired in order to deplete resources, to use these inorganic materials whose production is limited, and to prevent pollution caused by toxicity. ing.

In view of these points, research on electrophotographic photoconductors made of organic materials has been actively conducted in recent years, and some electrophotographic photoreceptors using various organic materials have been proposed and put into practical use. .

-For boat fishing, organic materials have better transparency than inorganic materials, are lightweight, are easy to form, have both positive and negative chargeability, and are used in the manufacture of photoreceptors. It also has the advantage of being easy to use.

By the way, typical examples of organic electrophotographic photoreceptors that have been proposed so far include polyvinyl carbazole and its derivatives, but these do not necessarily have film properties, scorch properties, solubility, adhesive properties, etc. However, it is not sufficient, and improved methods such as polyvinylcarbazole sensitized with biryllium salt dye (Japanese Patent Publication No. 48-25658) and polyvinylcarbazole and 2,4°7-dolinitrofluorenone sensitized (U.S. Pat. No. 3,484,237) have been developed. However, those that satisfy the basic properties, mechanical strength, and high durability requirements for photoreceptors listed above are:
I still don't get enough.

(C) Summary of the Invention The present inventor conducted research on photoconductive substances with high sensitivity and high durability, and as a result, discovered that the benzhydryl azomethine compound shown in the following (-Momona CI) is effective. This led to the present invention.

A, a, a' are hydrogen, a lower alkoxy group, a lower alkyl group, a halogen atom, B is hydrogen, a lower alkyl group, a phenyl group which may contain a substituent, R, R/ are a substituent an alkyl group that may contain a substituent, a phenyl group that may contain a substituent, a benzyl group that may contain a substituent, and an allyl group. ) The benzhydryl azomethine compound of general formula (1) according to the present invention is usually synthesized by the following synthesis process.

An aldehyde compound (B is hydrogen) or a ketone compound (B is an alkyl group, a phenyl group) represented by the general formula Ia and a benzhydrylamine compound represented by the -pattern 1b (wherein A, a, and B are the -patterns). (synonymous with hole (I)) (synonymous with hole (I)) (in the formula, a' is synonymous with -Moron hole CI)) can be obtained by reacting in a solvent by a conventional method. As a solvent, alcohols such as methanol and ethanol, acetic acid,
Solvents such as tetrahydrofuran, dioxane, and acetonitrile can also be used alone or in combination.

Depending on the case, a basic catalyst such as sodium alcoholade or aqueous ammonia, or an acidic catalyst such as acetic acid, hydrochloric acid, or P-)luenesulfonic acid may be used.

For the synthesis of some of these benzhydryl azomethine compounds, see Bull, Soc, Chmi of Fr.
ance1972.2.4584P%.

Specific examples of the benzhydryl azomethine compound useful in the present invention represented by the above-mentioned -Momona CI) include those having the following structural formula.

Exemplary Compounds The electrophotographic photoreceptor according to the present invention is obtained by containing one or more of the above-mentioned compounds of the 18 types, and has extremely excellent performance.

Various methods are known for using these benzhydryl azomethine compounds as electrophotographic photoreceptors. A photoreceptor formed by adding an attractive compound and dissolving or dispersing it in a binder on a conductive support, or a laminated structure consisting of a carrier generation layer with extremely high charge carrier generation efficiency and a carrier transport layer. In this form, the present benzhydryl azomethine compound is placed on a carrier generating layer mainly composed of a dye or pigment on a conductive support, and a Lewis acid compound or an electron-withdrawing compound is added thereto if necessary, and then added to a binder resin. There are photoreceptors in which a dissolved or dispersed carrier is provided as a carrier transfer layer, but it can be applied to either case.

When producing a photoreceptor using the benzhydryl azomethine compound of the present invention, a cylinder made of metal such as aluminum,
With the help of a film-forming binder, a film is formed on a support such as a metal plate, a film deposited with aluminum or the like, or a paper treated with electrically conductive material.

Various types of film-forming binders can be used depending on the field of use.

In other words, in the field of photoreceptors for copying, polystyrene resin,
Preferred are polyvinyl acetal resin, polysulfone resin, polycarbonate resin, acetic acid vinylcrotonic acid copolymer resin, polyphenylene oxide resin, polyester resin, alkyd resin, polyarylate resin, and the like.

These may be used singly or as a copolymer, or two types of polymers may be used.
More than one species can be mixed and used. Among them, resins such as Noryl, polyphenylene oxide, polycarbonate, polyarylate resin, etc., and binders having a volume resistivity of 10130 or more have excellent film properties, electrophotographic properties, etc.

Furthermore, the weight ratio of these binders added to the organic photoconductor is 0.2 to 20 times, preferably 0.5 to 5 times, and when it is less than 0.5, the organic photoconductor There is a drawback that the photosensitive layer is precipitated on the surface of the photosensitive layer, and when the amount is 5 times or more, the sensitivity decreases. Especially alkaline binders are required for use in lithography. An alkaline binder refers to an acidic group that is soluble in water or an alcoholic alkaline solvent (including mixed systems), such as an acid anhydride group, a carboxyl group, a phenolic hydroxyl group, a sulfonic acid group, a sulfonamide group, or a sulfonimide group. It is a polymer substance with

The binder preferably has a high acid value, usually 100 or more.

A binder resin with a high acid value easily dissolves or swells in an alkaline solvent.

These binder resins include, for example, styrene: maleic anhydride copolymer, vinyl acetate maleic anhydride, vinyl acetate crotonic acid, (meth)acrylic acid: (meth)acrylic acid ester, phenolic resin (meth)acrylic acid: styrene: (
It is a copolymer of meth)acrylic acid ester, etc.

Further, the proportion of these resins added to the photoconductor may be approximately the same as in the case of a photoconductor for copying.

Next, in the polymeric film-forming binder used, the photosensitive layer must be rigid and susceptible to mechanical properties such as tension, bending, and compression; in some cases, a substance that imparts plasticity may be added to improve these properties. It becomes necessary.

These substances include phthalates (e.g. DO
P, DBP, DIDP, etc.), phosphoric acid esters (eg, TcP, TOP, etc.), sebacic acid esters, adipic acid esters, epoxidized soybean oil, nitrile rubber, chlorinated hydrocarbons, and the like.

In addition, the proportion of these substances imparting reflexivity to the polymerizable film-forming binder is 0.1 chill2 by weight.
A content of up to 0% is preferable; a content of 0.1% or less is insufficient for improvement, and a content of 20% or more deteriorates the potential characteristics.

Next, the sensitizing dye added to the photosensitive layer is mef/l.
/ /< Triphenylmethane dyes represented by iolet, crystal violet, ethyl violet, night blue, Victoria blue, etc., xanthene dyes represented by erythrosine, rhodamine B, rhodamine 3B, acridine red B, etc., acridine orange Acridine dyes such as 2G, Acridine Orange R, and Flaveosin; thiazine dyes such as methylene blue, methylene green, and methyl violet; oxazine dyes such as Kavli Blue and Melt Lab; other cyanine dyes, and steryl dyes. These include dyes, pyrylium salts, and thiapyrylium salts.

Photoconductive pigments that generate charge carriers with extremely high efficiency through light absorption in the photosensitive layer include phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, perylene pigments such as perylene imide and perylene acid anhydride, and others. These include quinacridone pigments, azo pigments, and anthraquinone pigments.

In particular, pigments that generate charge carriers include trisazo pigments,
The use of bisazo pigments and phthalocyanine pigments provides electrophotographic photoreceptors with high sensitivity.

Further, the dye added to the photosensitive layer described above may be used as a charge carrier generating substance.

Although these dyes may be used alone, they often generate charge carriers with even higher efficiency when coexisting with pigments.

Further inorganic photoconductive substances include selenium, selenium telluride alloys, cadmium sulfide, zinc sulfide, and the like.

In addition to the sensitizers (spectral sensitizers) listed above, it is also possible to add a sensitizer (chemical sensitizer) for the purpose of increasing sensitivity.

Examples of chemical sensitizers include p-chlorophenol, m-
Chlorophenol, p-nitrophenol, 4-chloro-m-cresol, p-chlorobenzoylacetanilide, N,N'-diethylbarbylic acid, N,N'
-diethylthiobarbital acid, 3-(β-oxyethyl)-2-phenylimino-teazolidone, malonic acid dianilide, 3,5°3/, S/-tetrachloromalonic acid dianilide, α-naphthol, p- 2) Examples include oral benzoic acid.

Further, certain electron-withdrawing compounds can be added as sensitizers that combine with the benzhydryl azomethine compound of the present invention to form a charge transfer complex and further increase the sensitizing effect.

Examples of this electron-withdrawing substance include 1,4-bis(β
-cyano-β-alkoxycarbonylvinyl)benzene, 1-nitroanthraquinone, 2,3-cyclonaphthoquinone, 3,3'-dinitrobenzophenone, 4-nitrobenzalmalonenitrile, phthalic anhydride, a-(α-
Cyano-p-nitrobenzal) phthalide, 2,4.7-
) linitrofluorenone, 1-methyl-4-nitrofluorenone, 2,7-sinitro-3,6-dimethylfluorenone, and the like.

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

The benzhydryl azomethine compound of the present invention is dissolved or dispersed in an appropriate solvent together with the various additives mentioned above depending on the form of the photoreceptor, and the coating solution is coated on the conductive support described above, Dry to produce a photoreceptor.

Coating solvents include aromatic hydrocarbons such as benzene, toluene, xylene, and monochlorobenzene, dioxane,
Solvents such as methyl cellosolve acetate and dichloroethane may be used alone or in combination of two or more thereof, and if necessary, solvents such as alcohols, acetonitrile, N,N-dimethylformamide, and methyl ethyl ketone may be further added.

(Examples) Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these in any way.

In addition, "parts" in the following synthesis examples and examples indicate "parts by weight."

Synthesis Example 1 (Exemplary Compound & 2) 5.3 parts (0.03 mol) of diethylaminobenzaldehyde and 5.5 parts (0.03 mol) of tra-2enylmethylamine were dissolved in 30 mj of ethanol, and 1 drop of glacial acetic acid was added. The mixture was heated under reflux in a water bath for 2 hours.

If this reaction solution is left to reach room temperature, crystals will precipitate over the entire surface. After taking it out of the furnace, it was recrystallized again in ethanol to obtain 9.1 parts of white granular crystals.

The melting point was 121.0°C to 122.5°C.

Synthesis Example 2 (Exemplary Compound A17) Triphenylamine-4-carbaldehyde (melting point 13
6.5-138.0°C) 5.5 parts (0.02 mol) and 4.0 parts (0.02 mol) of diphinylmethylamine were dissolved in 70% ethanol and 1 drop of glacial acetic acid was added to synthesize Synthesis Example 1. Similarly, 7.8 parts of light-colored granular crystals were obtained. The melting point was 176.5-178.0°C.

Note that ethyl acetate was used as the recrystallization solvent.

(Example 1) A polyester film laminated with aluminum (Alpet 85 manufactured by Mitsubishi Plastics, film thickness 85μ, aluminum film thickness 10μ) was attached to the support, and a bisazo pigment represented by the following structural formula was applied to n-butylamine. 1% by weight
Apply the dissolved solution to a concentration of 0 and dry it to a film thickness of 0.
．． A 2μ film of charge generating material was formed.

Next, a benzhydryl azomethine compound represented by Exemplary Compound 7117 and a polyarylate resin (U-polymer manufactured by Unitika) were blended at a weight ratio of 1.2 il, and a 10% solution was prepared using dichloroethane as a solvent. This solution was applied onto the film of the generated substance using a squeezing doctor to form a carrier transfer layer with a dry film thickness of 18 μm.

The electrostatic photographic properties of the laminated electrophotographic material thus prepared were evaluated using an electrostatic recording paper tester (manufactured by Kawaguchi Electric Co., Ltd., 5P-428).

Measurement conditions: applied voltage -6 KV, static black 3 As a result, the light half-reduction exposure sensitivity to white light during charging was 2.5 lux·sec, which was a very high sensitivity value.

Furthermore, when repeated characteristic evaluations were conducted using the same apparatus, no tendency for electrophotographic characteristics to deteriorate, including light half-reduction exposure sensitivity, was observed even after repeating for 10 seconds or more.

Examples 2 to 6 Laminated photoreceptors were prepared in the same manner as in Example 1, except that the benzhydryl azomethine compounds shown in Table 1 were used in place of the benzhydryl azomethine compounds used in Example 1. , half-light exposure 1E-( under the same measurement conditions as Example 1)
Measure the initial potential Vo (volts) and
The values are shown in Table 1.

Furthermore, static electricity is applied - static neutralization (static neutralization light; 1 at 400 lux with white light)
Table 1 shows the initial potential Vo (in volts) and the light half-reduction exposure sensitivity B- (in lux/seconds) after carrying out the same operation for 1000 cycles, with one cycle being irradiation (seconds irradiation).

From Table 1, it can be seen that the photoreceptor using the benzhydryl azomethine compound of the present invention has excellent text sensitivity and repeatability characteristics.

Table 1 Example 7 A laminated photoreceptor was prepared in exactly the same manner as in Example 1 except that a trisazo pigment having the following structural formula was used in place of the bisazo pigment used in Example 1.

The 633 nm (He
-Ne laser) and 670nm (light emitting diode)
and the spectral sensitivity at 740 nm using a monochromator.
The energy required to reduce the potential by half is 5
．． 6 erg/d (633 nm), 4.9 erg/
i (670 nm) and 4.5 erg/cd (74
It was a photoreceptor with extremely high sensitivity (0 nm). Note that the initial potential was 960 (volts).

Examples 8 to 12 Add 0.2 t'z polyarylate resin (U-100 manufactured by Unitika) used in Example 7 to a dichloromethane solution containing 0.1 f, and add paint.
Dispersion was carried out in a conditioner (manufactured by Red Level Co., Ltd.) for about 2 hours, and a charge generation layer was formed on Sialpet 85 by the Dr. Plaid method so that the film thickness after drying was 0.4 μm.

A charge transfer layer containing the penzohydryl azomethine compounds of Examples 2 to 6 was laminated on the charge generation layer to prepare a photoreceptor.

The spectral sensitivities of these photoreceptors at 633 nm and 740 nm were measured in the same manner as in Example 7, and the energy required to reduce the potential by half is listed in Table 2.

Table 2 (Note) The initial potential (volts) of each photoreceptor is between 900 volts and 1050 volts.

Example 13 Bisazo pigment i represented by the following structural formula, ort-butyral resin (electrified butyral 3000) 0. ! M was added to a solution of 50% tetrahydrofuran and dispersed for about 2 hours using a paint conditioner, and then 50% tetrahydrofuran was added to this dispersion and dispersed again using ultrasound. The dispersion thus obtained was applied to a sialumium-deposited polyester film using an automatic applicator (manufactured by Yasuda Seiki) to a dry film thickness of 0.2.
Coating was carried out so that the thickness was 5μ.

Furthermore, exemplified benzhydryl azomethine compound 43
82. Of and polycarbonate resin (Lexan III
A transparent organic layer having a dry film thickness of 20 μm was obtained by laminating a solution obtained by dissolving 2.2f (manufactured by GB) in dichloroethane 20 μm. A portion of the photoreceptor thus obtained was heated at 40°C and 80%
The samples were stored at high temperature and high humidity to examine changes in electrophotographic properties before and after storage.

The results are listed in Table 3.

Comparative Example 1 A photoreceptor was prepared in exactly the same manner as in Example 13, except that the following hydrazone compound was used in place of Exemplary Compound A38, and changes in the electrophotographic characteristics of this photoreceptor under high temperature and high humidity were examined. The results are listed in Table 3.

As is clear from the above coating in Table 3, the photoreceptor using the benzhydryl azomethine compound of the present invention showed no change in properties in forced deterioration experiments under high temperature and high humidity, whereas the comparative example The hydrazone compound No. 1 showed a significant decrease in Vo.

Example 14 The photoreceptor obtained in Example 13 was irradiated with a 1000 lux halogen lamp for 3 minutes, and changes in electrophotographic characteristics immediately after irradiation were examined. Similarly, the photoreceptor obtained in Comparative Example 1 was also irradiated and the results are shown in Table 4.

As can be seen from Table 4, the light resistance of the benzhydryl azomethine compound of the present invention was 96%, whereas the light resistance of the hydrazone compound of the comparative example was 66%.

(Effects of the present invention) The effects of the electrophotographic photoreceptor using the nopenzohydryl azomethine compound of the present invention are summarized as follows.

(1) Highly charged and highly sensitive.

(2) Excellent repeat stability.

(3) Excellent light resistance and storage stability (stability over time).

The properties of the compound are as follows.

(1) Raw materials are inexpensive.

(2) Easy to synthesize.

(3) Good solubility.

(4) Little coloring. (In the case of a laminated photoreceptor, light suitable for the charge generation layer is absorbed.) It is concluded that this method is effective in forming an excellent photoreceptor in various respects.

Claims (6)

[Claims] (1) An electrophotographic photoreceptor characterized by containing a benzhydryl azomethine compound represented by the following general formula (I) in a photosensitive layer formed on a conductive support. ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・( I
) (In the formula, A is hydrogen, a lower alkoxy group, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, a, a' are hydrogen, a lower alkoxy group, a lower alkyl group, a halogen atom, and B is hydrogen , a lower alkyl group, a phenyl group which may contain a substituent, R and R' are an alkyl group which may contain a substituent, a phenyl group which may contain a substituent, a benzyl group which may contain a substituent, an allyl group .) (2) The electrophotographic photoreceptor according to claim 1, wherein the benzhydryl azomethine compound represented by the general formula (I) is a compound represented by the following structural formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R, R', and a are synonymous with the first term.) (3) Electrophotography according to claim 1, wherein the photoreceptor contains a carrier transfer substance and a carrier generation substance, and the carrier transfer substance is a benzhydryl azomethine compound represented by the general formula (I). Photoreceptor. (4) The electrophotographic photoreceptor according to claim 3, wherein the carrier generating substance is a trisazo pigment. (5) The electrophotographic photoreceptor according to claim 3, wherein the carrier generating substance is a bisazo pigment. (6) The electrophotographic photoreceptor according to claim 3, wherein the carrier generating substance is a phthalocyanine pigment.