JPS62242955A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the titled body having improved sensitivity and durability by incorporating a specific styril compd. as a carrier transfer substance to the titled body. CONSTITUTION:The styril compd. shown by the formula is incorporated in a photosensitive layer formed on a conductive substrate as the carrier transfer substance. In the formula, R' and R are each H, lower alkoxy or lower alkyl, etc., A is H, halogen or lower alkyl, etc., (m) and (n) are each 1 or 2. The carrier generating substance is preferably exemplified by a trisazo pigment, a bisazo pigment, a phthalocyanine pigment or an aquarium pigment. Thus, the tilted body having excellent electrostatic charge property and stability against a temp. and having less tendency for decreasing photosensitivity due to a repetitive use is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a photoreceptor for photoreceptor photography, particularly to a photoreceptor for organic electrophotography.

(Prior art) Traditionally, in electrophotography technology, non-virtuous substances such as selenium, cadmium sulfide, amorphous silicon, and zinc oxide have been widely used in the photosensitive layer of electrophotographic photoreceptors. Many studies have been conducted on the use of 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;

(2) The resulting corona charge has little attenuation in the dark.

(3) Charges are quickly dissipated by light irradiation.

(4) There is little residual charge after irradiation with light.

Conventional inorganic electrophotographic photoreceptors such as selenium and cadmium sulfide have basic properties that meet the requirements for photoreceptors, but there are manufacturing problems such as high toxicity and difficulty in film formation. However, in the future, the use of these inorganic materials, which are not flammable and have limited production, will be more desirable than the use of these inorganic materials. In view of pollution caused by toxicity, it is desired to use photoreceptors made of organic materials instead of inorganic materials.

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

In general, organic materials have better transparency, lighter weight, better film-forming properties, and better sintering properties than inorganic materials, and they can be used with photoreceptors using appropriate sensitization methods. It has advantages such as easy design.

By the way, typical examples of organic electrophotographic photoreceptors that have been proposed so far include polyvinylcarbazole and its conductor, but these do not necessarily have sufficient film properties, burnability, or adhesive properties. , and polyvinylcarbazole sensitized with pyrylium salt dye (Special Publication No. 4)
8-25658), polyvinylcarbazole and 2.4
．． 7-) and those sensitized with nitrofluorenone (U.S. Pat. No. 3,484,237), although they have been improved, do not meet the basic force properties, mechanical strength, and high There is still not enough material that satisfies requirements such as durability.

(Object of the Invention) An object of the present invention is to provide an electrophotographic photoreceptor having high sensitivity and high durability. Particularly, it is an object of the present invention to provide an inexpensive photoreceptor which has excellent temperature stability and high charging characteristics, and which exhibits almost no decrease in photosensitivity even after repeated use.

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

4□ (In the formula, R', R is hydrogen, lower alkoxy, lower alkyl R
1 Kyl, halogen, -N\几, deJ, , R#, R# are lower alkyl, allyl, benzyl which may contain a substituent, A is hydrogen, )・rogen, lower alkyl, lower alkoxy Deta, m%n Iri 1 or 2 and 5n
When is 2, R' and 几 may be the same or different. ) The styryl compound represented by the general formula (I) of the present invention is usually synthesized by the following synthesis process.

(R, R,', A, and n%m have the same meanings as above.) Examples of the compounds represented by the general formula (II) include the following compounds.

Exemplary styryl compounds Among these exemplified compounds, those that are particularly good in terms of performance and cost are Bian 7, A8, l617, Ni 18, A20, and A.
There are 24 compounds listed.

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

Also, hydrazone compounds (e.g. P-N, N-diethylaminobenzaldehyde-N,N-diphenylhydrazone) or oxadiazole compounds (e.g. Eva 2.5-
Bis-(p-diethylaminophenyl)-1,3,4
-oxadiazole) pyrazoline compounds (e.g. 1-P
A photoreceptor with extremely excellent performance can also be obtained by mixing a compound such as -diethylaminophenyl-3°5-diphenylpyrazoline.

Various methods are known for using these styryl compounds as electrophotographic photoreceptors. A photoreceptor is prepared by dissolving or dispersing a photoreceptor in a conductive support on a conductive support, or in the form of a laminated structure consisting of a carrier generation layer with extremely high charge carrier generation efficiency and a carrier transfer layer. A carrier transport layer is prepared by dissolving or dispersing this styryl compound in a binder, with the addition of a chemical sensitizer or an electron-withdrawing compound as necessary, on a carrier generation layer mainly composed of a sensitizing dye or pigment. There is a photoreceptor provided as a photoreceptor, but it can be applied to any case.

When producing a photoreceptor using the compound of the present invention, it is possible to form a polymer film on a support such as a metal drum, metal plate, conductively treated paper, conductively treated plastic film, or belt. It forms a film with the help of a binder.

In this case, in order to further increase the sensitivity, it is desirable to add a substance imparting plasticity to the sensitizer or polymerizable film-forming binder as described below to form a uniform photosensitive layer film.

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

That is, in the field of photoreceptors for copying, polystyrene resin, polyvinyl acetal resin, polysulfone resin, polycarbonate resin, acetic acid vinyl crotonic acid copolymer resin,
Polyphenylene ogicide resins, polyester resins, alkyd resins, polyarylate resins, etc. are preferred.

These may be used singly or as a copolymer poly→- or two
More than one species can be mixed and used.

Among them, resins such as polystyrene, polyphenylene oxide, polycarbonate, polyarylate, etc., and binders having a volume resistivity of 10150 or more have excellent film properties, potential properties, etc.

The amount of these binders added to the organic photoguide is 0.2 to 20 times, preferably 0.5 to 5 times by weight.
If the ratio is less than 0.5, the organic photoconductor will precipitate from the surface of the photosensitive layer, and if it is more than 5 times, the sensitivity will decrease.

Especially alkaline binders are required for use in lithography.

An alkaline binder is 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 sulfone group. It is a polymer substance with imide groups.

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.

Examples of these binder resins include styrene: maleic anhydride copolymer, vinyl acetate maleic anhydride, vinyl acetate crotonic acid, methacrylic acid: methacrylic ester, phenol resin, methacrylic acid: styrene: methacrylic ester, etc. It is a copolymer of

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

In the polymer film-forming binder used next, the photosensitive layer is hard and weak in mechanical properties such as tensile, bending, and compression, and in order to improve these properties, a substance that imparts plasticity may be added. 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 plasticity to the polymerizable film-forming binder is 0.1% to 2% 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 dyes added to the photosensitive layer include triphenylmethane dyes represented by methyl violet, crystal violet, ethyl violet, night blue, Victoria blue, etc., erythrosine, rhodamine B10-tamin 3B1 acridine red. Xanthene dyes such as B1; acridine dyes such as Acridine Orange 2G and Acridine Orange R1 frapeosin; thiazine dyes such as methylene blue, methylene green, and methyl violet; These include oxazine dyes, other cyanine dyes, styryl dyes, pyrylium salts, thiapyrylium salts, and squareium salts.

Photoconductive pigments that generate charge carriers with extremely high efficiency through light absorption in the photosensitive layer include 7-lycyanine M materials such as metal phthalocyanine and metal-free phthalocyanine, perylene such as perylene imide and perylene acid hydrothermal hydrate. pigments, other quinacridone pigments, azo pigments, and anthraquinone pigments.

In particular, those using trisazo pigments, bisazo pigments, 7-thalocyanine pigments, and squalium salt dyes as pigments that generate '-charge charge give high sensitivity and provide excellent electrophotographic photoreceptors.

Further, it may be incorporated as a dye+m charge carrier generating substance added into the above-mentioned photosensitive layer.

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'-diethylbarbyl [, N,N'-diethylthiobarbyl id, 3-( Examples include B-oxyethyl)-2-phenylimino-thiazolidone, malonic acid dianilide, 3,5°a/, S/-tetrachloromalonic acid dianilide, and α-naphthol-P-nitrobenzoic acid.

It is also possible to add a polar electron-withdrawing compound as a sensitizer that combines with the styryl compound of the present invention to form a charge transfer complex 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,
-(α-cyano-P-nitrobenzal)lid IJ)'
, 2.4.7-) linitrofluorenone, 1-methyl-4-nitrofluorenone, 2.7-sinitro 3.6
-dimethylfluorenono etc.

Other additives to the photoreceptor, such as antioxidants and anti-curl agents, can be added as necessary.

The styryl compound of the present invention is dissolved or dispersed in a suitable solvent together with the various additives mentioned above depending on the form of the photoreceptor, and the coating solution is applied onto the conductive support described above and dried. A photoreceptor is manufactured.

Coating solvents include aromatic hydrocarbons such as benzene, toluene, xylene, and monochlorobenzene, dioxane,
Solvents such as methyl cellosolve acetate alone or in combination
A mixed solvent of more than one species or a solvent such as alcohols, acetonitrile, N,N-dimethylformamide, methyl ethyl ketone, etc. may be added if necessary.

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.

Example 1 A polyester film laminated with aluminum (Alpet 85 manufactured by Mitsubishi Plastics, film thickness 85μ, aluminum film thickness 10μ) was used as a support, and a bisazo pigment represented by the following structural formula was added to n-butylamine on the support. 1% by weight
Apply the dissolved solution to a concentration of 0 and dry it to a film thickness of 0.
．． A 5 micron coating of charge generating material was formed.

Next, a styryl compound shown by Exemplary Compound Point 7 (melting point 123-125.5°C) was blended with a polyarylate resin (Unitika fiU-Polymer) at a ratio of 1:1, and a 10% solution was prepared using dichloroethane as a solvent. This solution was then applied onto the film of the carrier generating substance using an applicator to form a carrier transport layer having a dry thickness of 18 μm.

The laminated electrophotographic photoreceptor thus produced was evaluated for its photographic properties using an electrostatic recording paper tester (Ro'iir, Kikai 5P-428).

Measurement conditions: Applied voltage -6 KV, static boiling 3 As a result, the light half-reduction exposure amount to white light during charging was 3.0 lux·sec, which showed a very high sensitivity value.

Furthermore, when repeated characteristic evaluations were carried out using the same apparatus, no tendency of deterioration in electrophotographic characteristics, including potential and light half-exposure sensitivity, was observed even after repeating 103 times or more.

Examples 2 to 6 J-thermal photoreceptors were prepared in the same manner as in Example 1, except that the styryl compounds shown in Table 1 were used in place of the styryl compounds used in Example 1. Under the same measurement conditions, the optical half-reduction exposure iB' (lux seconds) and the initial potential Vo
(in volts) and the values are shown in Table 1. Furthermore, after carrying out the same operation for 1000 cycles, with 1 cycle of charging and neutralization (static discharge light: irradiated with white light at 400 lux for 1 second), the initial potential Vo (volt) and the light half-reduction exposure sensitivity E-L ( lux seconds) are shown in Table 1.

A photoreceptor was prepared by laminating a charge transfer layer containing a compound in accordance with Example 1.

The spectral sensitivities of these photoreceptors at 633 nm and 670 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 Example 15 Add 0.11 of the polymethine dye shown in the structure below to a 30% sweet solution of copolymer nylon (Toyo Rayon ucM-8000) 5m dissolved in a mixed solvent of ethanol and methyl alcohol to make a homogeneous solution. .

The solution prepared in this manner was applied onto an aluminum vapor-deposited film so that the film thickness after drying was 0.2 μm.

Next, 2 tons of styryl compound of Exemplary Compound 24 was added to 1.5F of styrene resin (Mitsubishi Monsando Styron-685).
and polybutyl methacrylate resin (manufactured in-house) O, S
t was dissolved in 20rnt of toluene, and this solution was coated in a layered manner on the carrier generation layer by the Doctor Plaid method to form a carrier transfer layer of about 10μ.

780 nm of the electrophotographic photoreceptor produced in this way,
When the spectral sensitivity at 820 nm and 840 nm was measured in the same manner as in the example, it was 10 erg/a/l (7
80 nm), 8 erg/m (820 nm), 7
The photoreceptor was found to be highly sensitive even in near-infrared light (e.g., erg/ci (840 nm)).

Claims (10)

[Claims] (1) An electrophotographic photoreceptor characterized by containing a styryl 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, R′ and R are hydrogen, lower alkoxy, lower alkyl, halogen, ▲numerical formula, chemical formula, table, etc.▼, and R″ and R″′ may include lower alkyl, allyl, and a substituent. is benzyl, A is hydrogen, halogen, lower alkyl, or lower alkoxy, m and n are 1 or 2, and when m and n are 2, R' and R may be the same or different.) (2) Claim 1, wherein the styryl compound represented by the general formula (I) is a compound represented by the following structural formula:
The electrophotographic photoreceptor described in . ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (R″ and R″′ are the same as the first term.) (3) Claim 1, wherein the styryl compound represented by the general formula (I) is a compound represented by the following structural formula:
The electrophotographic photoreceptor described in . ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ (4) Claim 1, wherein the styryl compound represented by the general formula (I) is a compound represented by the following structural formula:
The electrophotographic photoreceptor described in . ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ (5) Claim 1, wherein the styryl compound represented by the general formula (I) is a compound represented by the following structural formula:
The electrophotographic photoreceptor described in . ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ (6) The photosensitive material for 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 styryl compound represented by the general formula (I). body. (7) The electrophotographic photoreceptor according to claim 6, wherein the carrier generating substance is a trisazo pigment. (8) The electrophotographic photoreceptor according to claim 3, wherein the carrier generating substance is a bisazo pigment. (9) The electrophotographic photoreceptor according to claim 3, wherein the carrier generating substance is a phthalocyanine pigment. (10) The electrophotographic photoreceptor according to claim 3, wherein the carrier generating substance is a squalium salt dye.