JPS63128352A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain high sensitivity and high durability by incorporating a specified stilbene compound in a photosensitive layer formed on a conductive substrate. CONSTITUTION:The photosensitive layer formed on the conductive substrate contains one of the stilbene compounds represented by formula I in which each of A and B is lower alkyl or aryl and each of R and R' is H, alkoxy, alkyl, tertiary amine, or halogen. These stilbene compounds are embodied by formulae II in which A is same as A in formula I, thus permitting the requirements of elementary properties, mechanical strength, high durability, and the like to be satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, and more specifically, the present invention relates to a photoreceptor for electrophotography, and more specifically, the present invention relates to a photoreceptor having the following general formula (
The present invention relates to an electrophotographic photoreceptor containing a stilbene compound represented by I).

(In the formula, A%B represents a lower alkyl group, an aryl group, and R and R' represent hydrogen, an alkoxy group, an alkyl group, a tertiary amine group, or a halogen.) Conventionally, electrophotographic photoreceptors have been used in electrophotographic technology. Inorganic materials such as selenium, cadmium sulfide, amorphous silicon, and zinc oxide are widely used in the photosensitive layer of photosensitive materials, but in recent years, much research has been conducted on the use of organic photoconductive materials as electrophotographic photoreceptors. I'm here.

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. etc.

Conventional inorganic electrophotographic photoreceptors such as selenium and cadmium sulfide have basic properties that allow them to be used as photoreceptors, but they have manufacturing problems such as high toxicity and difficulty in film formation. They have drawbacks such as high flammability and high manufacturing costs.In the future, in order to deplete resources, the use of these non-nuclear materials, which have limited production, will be considered. Furthermore, in view of the 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 are some things.

In general, organic materials have better transparency than inorganic materials, are lighter in weight, are easier to form, have both positive and negative chargeability, and are easier to manufacture photoreceptors. It 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. Enough left <, Also, polyvinylcarbazole sensitized with pyrylium salt dye (Japanese Patent Publication No. 48-25658) and polyvinylcarbazole and 2.4.7-) linitrofluorenone sensitized (US Patent No. 3,484,237) 1 Although some improvements have been made, there is still no material that satisfies the basic properties, mechanical strength, high durability, etc. requirements of a photoreceptor as mentioned above.

The present inventors conducted research on photoconductive substances having high sensitivity and high durability, and as a result, they found that the stilbene compound represented by the above general formula (1) is effective, leading to the present invention.

The stilbene compound of general formula (I) related to the present invention is:
It is usually synthesized using the following synthesis process.

D. =0□−6□. ,. ,,. 95, xe, ge) 1/ (In the above reaction formula, X is halogen, A, R.

R' is a synonym with general formula (I). ) Said general formula (I
) Examples of the stilbene compounds useful in the present invention include compounds having the following structural formula.

Exemplary compound Boiled 3 The specific synthesis of these exemplary compounds will now be described.

Synthesis Example (Exemplary Compound & 6) 1.1-bis(p-dimethylaminophenyl)acrolein (4.62 g) and benzohydryl-triphenylphosphonium chloride (9.5 f) in 100 g of ethanol! At an internal temperature of 50°C, 50°C of a 0°4N lithium ethoxide solution was added, and the mixture was allowed to react at an internal temperature for 10 hours. After completion, ethanol was distilled off and the residue was diluted with isopropyl ether 8
〇- Reconsolidate to obtain fluorescent yellow powder 6.32.

Melting point: 136.5-138.0℃ The mass spectrum showed a value of 444.

Other compounds can also be easily obtained according to the above synthesis.

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.

Various methods are known for using these stilbene compounds as electrophotographic photoreceptors. A photoreceptor is prepared by dissolving or dispersing a dye 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. Alternatively, a carrier transport layer is formed by dissolving or dispersing the present stilbene compound in a binder resin (with the addition of a Lewis acid compound or an electron-withdrawing compound in some cases) on a carrier generation layer mainly composed of a pigment. There are photoreceptors equipped with
It is possible to apply in either case.

When producing a photoreceptor using the stilbene compound of the present invention, a film-forming binder is applied onto a support such as a metal cylinder, a metal plate, a film deposited with aluminum or the like, or paper treated with conductivity. Form a film with the help of

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, vinyl acetate:crotonic 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 polystyrene, polyphenylene oxide, polycarbonate, polyarylate resin, etc., and binders having a volume resistivity of 10130 or more have excellent film properties, potential properties, etc.

The amount of these binders to be added to the organic photoconductor is 0.2 to 20 times by weight, preferably 0.5 to 5 times, and when the weight ratio is 0.5 or less, the organic photoconductor becomes This has the disadvantage that it precipitates on the surface of the photosensitive layer, and when it is 5 times or more, it causes a decrease in sensitivity.

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 ester, phenol resin, (meth)acrylic acid: sterene. :
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.

In the film-forming binder used next, the photosensitive layer must be hard and weak against mechanical properties such as tension, bending, and compression, and it may be necessary to add a substance that imparts plasticity to improve these properties. becomes.

These substances include phthalates (e.g. DO
(P, DBP, DIDP, etc.), phosphate esters (such as TCP, TOP, etc.), sebacic acid esters, adipate esters, epoxidized soybean oil, 2) IJ rubber, and chlorinated hydrocarbons. In addition, the proportion of these substances imparting plasticity added to the polymerizable film-forming binder is preferably between 0.1% and 20% by weight; less than 0.1% is insufficient for improvement. If it exceeds 20%, the potential characteristics will deteriorate.

Next, the sensitizing dyes added to the photosensitive layer include triphenylmethane dyes R such as methyl violet, crystal violet, ethyl violet, night blue, Victoria blue, etc., erythrosine, rhodamine B, rhodamine 3B, and acridine. Zansen dyes such as Red B1 and Acridine Orange 2G.

Acridine dyes such as Acridine Orange R1 Flaveosin, methylene blue, methylene green,
Examples include thiazine dyes such as methyl violet, oxazine dyes such as Kavli Blue and Meltora Flue, other cyanine dyes, styryl dyes, pyrylium salts, and thiapyrylium salts.

Photoconductive pigments that generate charge carriers with extremely high efficiency through light absorption in the photosensitive layer include 7-thalocyanine pigments such as metal phthalocyanine and non-metal phthalocyanine, and perylene pigments such as perylene imide and perylene acid hydrothermal solution. , other quinacridone pigments, azo pigments, anthraquinone pigments, etc.

In particular, pigments that generate charge carriers include trisazo pigments,
Those using bisazo pigments and phthalocyanine pigments provide high sensitivity and provide excellent electrophotographic photoreceptors.

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.

Furthermore, examples of inorganic photoconductive substances include selenium, selenium tellurium alloy, cadmium sulfide, zinc sulfide, and amorphous silicon.

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 Lewis acid compounds include p-chlorophenol,
m-chlorophenol, p-nitrophenol, 4-chloro-m-cresol, p-chlorobenzoylacetanilide, N,N/-diethylbarbyl LN, N'-
Diethylthiobarbital acid, a-(β-oxyethyl)-2-phenylimino-teazolidone, malonic acid dianilide, 3,5.3',5'-tetrachloromalonic acid dianilide, α-naphthol, p-nitro Examples include benzoic acid.

Further, certain electron-withdrawing compounds can be added as sensitizers that combine with the stilbene compound of the present invention to form a charge transfer complex and further increase 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-) Rinitrofluorenone, 1-methyl-4-nitrofluorenone, 2,7-sinitro3,6-cy)l
Examples include f-fluorenone.

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

The stilbene 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 applied onto 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 tetrahydrofuran and methyl cellosolve acetate may be used alone or in combination of two or more, and if necessary, solvents such as alcohols, acetonitrile, N,N-dimethylformamide, and methyl ethyl ketone may be further added.

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

Example 1 A polyester film laminated with aluminum (Alvet 85 manufactured by Mitsubishi Plastics, film thickness 85 μm, aluminum film thickness 10 μm) 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 2μ film of charge generating material was formed.

Next, a stilbene compound represented by Exemplary Compound A3 and a polyarylate resin (U-polymer manufactured by Unitika) were mixed in a ratio of 1:1.
10 by using dichloroethane as a solvent.
After applying the solution of q6, this solution was applied onto the film of the carrier generating substance using a squeezing doctor to form a carrier transfer layer having a dry film thickness of 18 μm.

The electrophotographic properties of the thus produced laminated electrophotographic body were evaluated using an electrostatic recording paper tester (Kawaguchi Electric Co., Ltd. FF8P-428).

Measurement conditions: applied voltage -6 KV, static A3 As a result, the original light exposure sensitivity to white light during charging was 2.5 lux·sec, which was a very high sensitivity value.

Further, when repeated characteristic evaluations were carried out using the same apparatus, no tendency of deterioration in the electrophotographic characteristics, including initial exposure sensitivity, was observed even after repeating the test 103 times or more.

Examples 2 to 6 Laminated photoreceptors were prepared in the same manner as in Example 1, except that the stilbene compounds shown in Table 1 were used as substitute 9 for the stilbene compounds used in Example 1. With the measuring thread attached, the initial reduced exposure amount E, (lux/second) and initial potential V
o (volts) was measured and the values are shown in Table 1. Furthermore, static electricity is applied - static neutralization (static neutralization light: 0.3 at 300 lux with white light)
Table 1 shows the initial potential To (volts) and light reduction exposure sensitivity E, (lux/second) after performing the same operation for 1,000 cycles, with one cycle being irradiation (second irradiation).

It can be seen from Table 1 that the photoreceptor using the stilbene compound of the present invention has excellent sensitivity and repeatability.

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.
33 μm (He-Ne V-ther) and 670 μm (
A monochromator measures the spectral sensitivity of light emitting diodes.
The energy required to reduce the potential by half is 4
．． 5 erg/al (633 nm), 4°2 er
It was a photoreceptor with extremely high sensitivity of g/al (670 nm). Note that the initial potential was 880 (volts).

Examples 8 to 12 0.2 f of the trisazo pigment used in Example 9 was added to 30 d of a dichloromethane solution in which 0.1 f of polyarylate resin (U-100 manufactured by Unitika) was dissolved, and the mixture was added to a paint conditioner (manufactured by Red Level Co., Ltd.). Dispersion was carried out 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 exemplified stilbene compounds shown in Table 2 was laminated on this charge generation layer to prepare a photoreceptor.

The spectral sensitivities of these photoreceptors at 633 μm and 670 μm were measured in the same manner as in Example 9, and the energy required to reduce the potential by half is listed in Table 2.

Table 2 Example 13 0.5f of a polymethine dye having the following structure was added to 30ml of a 3% by weight solution of butyral resin (degree of butyralization: 65cm) dissolved in tetrahydrone run to form a homogeneous solution.

Step 0 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 the stilbene compound of Tori 6, which is an exemplary compound, was added to 1.5 liters of styrene resin (Mitsubishi Monsando Styron-85).
F and hypophenylene oxide resin (Mitsubishi Gas Chemical Exhibition) O, St were dissolved in 20 grams of toluene, and this solution was coated in a layer on the carrier generation layer using the Dr. Plaid method, and the carriers were transferred by about 10μ. formed a layer.

The electrophotographic photoreceptor prepared in this way was 780 μm, 8
When the spectral sensitivity at 20 μm and 840 μm was measured in the same manner as in the example, it was 8 erg/al (780 μm), 8 e
rg/crl (820nm), 10 erg/d(
It was found that the photoreceptor has high sensitivity even in the near-infrared region (840 μm).

Example 14 Styrene: n-butyl methacrylate: methacrylic acid (styrene: n-butyl methacrylate 2221 weight ratio, acid value 185) and Exemplary Compound Boiled 7 were mixed at 1.5:1 on a grained surface oxidized M plate. 4-(p-diethylaminophenyl)-2,6-cy1)-)lylthiapyrylium perchlorate (thiapyrylium salt pigment)
of the exemplified compound in a weight ratio of 5 x 10' to make a 10% by weight solution using dioxane as a solvent,
Apply this solution with a squeegee doctor and let it dry.
A single-layer photoreceptor with a film thickness of approximately 5 μm was prepared.

The electrophotographic characteristics of the thus prepared photoreceptor were evaluated using the electrostatic recording paper tester described above.

Evaluation conditions: applied voltage -6ff, static -3, initial potential 470 (volts), original light exposure amount 8.0 (lux-seconds).

In addition, this photoreceptor is visualized with a developer (toner), and then an alkaline processing liquid (for example, 3-tanolamine, 1-1
0% ammonium carbonate and 20% average molecular weight 190-2
When treated with polyethylene glycol No. 10), the toner-free areas were easily eluted, and by washing with water containing sodium silicate, a printing original plate could be easily prepared.

When offset printing was performed using this original plate, it was found that it could withstand printing of about 100,000 sheets.

In addition, in order to obtain a toner visible image (light source: halogen lamp)
The optimum exposure was 1 second at 100 lux.

In addition, except for creating the original printing plate, direct plate making was performed without using any printing material.

Example 15 In place of the thiapyrylium salt dye used in Example 4, δ-type copper phthalocyanine was added at a weight ratio of 10 parts of the stilbene compound of Exemplified Compound A8, and the phthalocyanine was sufficiently dispersed in a ball mill, followed by the same procedure as in Example 14. A single layer type photoreceptor with a film thickness of about 4 μm was prepared.

Looking at the electrophotographic characteristics of this photoreceptor, it was found that the initial potential was 530 (volts) and the initial reduced exposure was i-8.0 (lux seconds).

The photoreceptor thus obtained was exposed, developed, alkaline treated, washed with water, and the printing original plate obtained was about 1
It was found that it can withstand printing of 10,000 sheets.

The exposure was performed using monochromatic light of 633 nm, and the optimum irradiation energy was about 100 erg.

[Brief explanation of the drawing]

FIG. 1 is a one-pot spectrum diagram of Swallow 6, an exemplary compound of the present invention.

Claims (8)

[Claims] (1) An electrophotographic photoreceptor characterized in that a stilbene compound represented by the following general formula (I) is contained in a photosensitive layer formed on a conductive support. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) (In the formula, A and B represent lower alkyl groups and aryl groups, and R and R' represent hydrogen, alkoxy groups, alkyl groups, and tertiary amino (represents a group or halogen) (2) The electrophotographic photoreceptor according to claim 1, wherein the stilbene compound represented by the general formula (I) is a compound represented by the following structural formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (A in the formula is a synonym for the first term.) (3) The electrophotographic photoreceptor according to claim 1, wherein the stilbene 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″ is a lower alkyl group or a benzyl group that may contain a substituent, and A is a synonym for the first term.) (4) The electrophotographic photoreceptor according to claim 1, wherein the stilbene 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″ is synonymous with the third term, and A and R′ are synonymous with the first term. (5) The electrophotographic photoreceptor according to claim 1, wherein the photoreceptor contains a carrier transfer substance and a carrier generating substance, and the carrier transfer substance is a stilbene compound represented by the general formula (I). (6) The electrophotographic photoreceptor according to claim 6, wherein the carrier generating substance is a trisazo pigment. (7) The electrophotographic photoreceptor according to claim 6, wherein the carrier generating substance is a bisazo pigment. (8) The electrophotographic photoreceptor according to claim 6, wherein the carrier-generating substance is a phthalocyanine pigment.