JPH0314339B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor containing a hydrazone compound represented by the following general formula () in a photosensitive layer formed on a conductive support. be. (In the formula, R ₁ is

【formula】

【formula】

【formula】

[Formula], R ₂ is hydrogen, -OCH ₃ , -OC ₂ H ₅ , -CH ₃ , -C ₂ H ₅ , halogen, and R ₃ is hydrogen, -CH ₃ , -C ₂ H ₅ , phenyl and
R ₄ is phenyl substituted with bromo, chloro, methyl or methoxy, R ₅ is -CH ₃ , -C ₂ H ₅ , -
OCH ₃ , represents halogen. n is 0 or 1, m is 1, 2 or 3, and l is 1 or 2. ) Conventionally, in electrophotographic technology, inorganic materials such as selenium, cadmium sulfide, amorphous silicon, and zinc oxide have been widely used in the photosensitive layer of electrophotographic photoreceptors, but in recent years organic photoconductive materials have been used. Many studies have been conducted on the use of electrophotographic photoreceptors. Here, the basic properties required for an electrophotographic photoreceptor are (1) High chargeability due to corona discharge in the dark. (2) The resulting corona charge has little attenuation in the dark. (3) Charge is quickly dissipated by light irradiation. (4) There is little residual charge after irradiation with light. etc. Selenium, a conventional inorganic material electrophotographic photoreceptor,
Cadmium sulfide and other materials meet the requirements for photoreceptors in terms of basic properties, but there are manufacturing problems such as high toxicity, difficulty in film formation, lack of flexibility, and manufacturing costs. However, in the future, the use of inorganic materials is more important than the use of inorganic materials, whose production is limited due to depletion of resources, and in terms of pollution caused by toxicity. The use of organic photoreceptors is desired. 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, and are easier to form into films.
It has the advantage of being negatively charged in both directions and easy to manufacture photoreceptors. By the way, typical organic electrophotographic photoreceptors that have been proposed so far include polyvinyl carbazole and its derivatives, but these do not necessarily have sufficient film properties, flexibility, solubility, adhesive properties, etc. In addition, polyvinylcarbazole is sensitized with pyrylium salt dye (Special Publication 1973-
25658) and polyvinylcarbazole and 2,4,7
- Although there are improved products such as those sensitized with trinitrofluorenone (U.S. Patent No. 3,484,237), they still satisfy the basic properties, mechanical strength, and high durability requirements of photoreceptors as listed above. I still don't get enough of what I want. The present inventors conducted research on photoconductive substances having high sensitivity and high durability, and as a result, they discovered that the hydrazone compound represented by the above general formula () is effective, leading to the present invention. The hydrazone compound of the general formula () according to the present invention is usually synthesized by the following synthesis process. First, an aldehyde represented by general formula (a-1),
The ketone compound represented by the general formula (a-2) and the phenylhydrazine derivative represented by the general formula (b) are heated and stirred in a solvent such as alcohol, with the addition of an alkaline solvent such as sodium acetate if necessary. Thus, hydrazone compounds represented by general formulas (C-1) and (C-2) are synthesized. (R ₁ , R ₂ , R ₃ , R ₄ , and n in each of the above general formulas have the same meanings as R ₁ , R ₂ , R ₃ , R ₄ , and n in the general formula ().) Synthesis in this way The general formulas (C-1) and (C-2) can be converted into the general formula () by using a halomethylbenzene derivative represented by the general formula (d) and a strongly alkaline compound (e.g. caustic soda) as a catalyst. The hydrazone compound shown can be obtained. Although this reaction may be carried out in a solvent-free system, it is usually preferable to carry out the reaction by adding water, dimethyl sulfoxide, etc., since the reaction system can be adjusted. (R ₅ in general formula (d) has the same meaning as R ₅ in general formula (), and X represents a halogen.) In addition to these synthetic methods, general formulas (a-1), (a
There is also a method of synthesizing general formula (2) by directly reacting a hydrazine derivative represented by general formula (e) with alcohol or the like. (R ₄ and R ₅ in general formula (e) are R 4 and R ₅ in general formula (),
(Synonymous with _R5 ) Examples of the compounds of the present invention obtained by such a method include the following. 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, other hydrazone compounds (e.g. P-N, N
-diethylaminobenzaldehyde-N,N-diphenylhydrazone) or oxadiazole compounds (e.g. 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 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, with the addition of a chemical sensitizer or an electron-withdrawing compound if necessary, on a conductive support. The present hydrazone is applied on a carrier generating layer mainly composed of a sensitizing dye or a pigment on a conductive support in the form of a layered structure consisting of a carrier generating layer with extremely high charge carrier generating efficiency and a carrier transfer layer. There are photoreceptors in which a carrier transport layer is provided with a compound dissolved or dispersed in a binder with the addition of a chemical sensitizer or an electron-withdrawing compound if necessary. It is possible to apply. In preparing photoreceptors using the compounds of this invention, a polymeric film-forming binder is applied onto a support such as a metal plate, conductively treated paper, or conductively treated plastic film. Borrow it and make it into a film. In this case, in order to further increase the sensitivity, it is desirable to add a sensitizer as described below or a substance that imparts plasticity to the polymerizable film-forming binder to form a uniform photosensitive layer film. Various types of polymerizable film-forming binders can be used depending on the field of use. In other words, in the field of photoreceptors for copying, polystyrene resin, polyvinyl acetal resin, polysulfone resin, polycarbonate resin, acrylic resin,
Preferable examples include methacrylic resin, vinyl acetate resin, acetic acid-bicrotonic acid copolymer resin, polyphenylene oxide resin, polyester resin, and alkyd resin. These can be used alone or in combination as a copolymer. Among them, resins such as polystyrene, polyphenylene oxide, and polycarbonate have a volume resistivity of 10 ¹³ Ω or more, and binders have excellent film properties, potential properties, etc. In addition, the amount of these binders added to the organic photoguide is 0.2 to 20 times the weight ratio.
Preferably, when it becomes 0.5 or less in the range of 0.5 to 5 times,
There is a drawback that the organic photoconductor precipitates from the surface of the photosensitive layer, and when the increase is 5 times or more, sensitivity decreases. For use in lithographic printing, an alkaline binder is particularly required. An alkaline binder is an acidic group that is soluble in hydrogen or alcoholic alkaline solvents (including mixed systems), such as acid anhydride groups, carboxyl groups, phenolic hydroxyl groups, sulfonic acid groups, sulfonamide groups, or sulfonimide groups. It is a polymer substance with 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. These binder resins include, for example, styrene:
Maleic anhydride copolymer, vinyl acetate: maleic anhydride, vinyl acetate: crotonic acid (meth)acrylic acid: (meth)acrylic ester, phenolic resin (meth)acrylic acid: styrene: (meth)acrylic ester, etc. It is a copolymer. 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, depending on the polymer film-forming binder used, the photosensitive layer may be rigid and weak in mechanical properties such as tension, bending, and compression, and in order to improve these properties, a substance that imparts plasticity may be added. is also required. These substances include phthalate esters (e.g. DOP, OBP, DIDP, etc.), phosphate esters (e.g. TCP, TOP, etc.), sebacate esters,
Examples include adipate esters, epoxidized soybean oil, nitrile rubber, and chlorinated hydrocarbons. In addition, the proportion of these substances imparting plasticity to the polymerizable film-forming binder is preferably between 0.1% and 20% by weight; less than 0.1% is insufficient for improvement, and more than 20% is preferable. This will worsen the potential characteristics. Next, as the sensitizing agent added to the photosensitive layer,
Methyl violet, crystal violet,
Triphenylmethane dyes represented by ethyl violet, night blue, Victoria blue, etc., erythrodine, rhodamine B, rhodamine
3B, Acridine Red B, etc., acridine dyes such as Acridine Orange 2G, Acridine Orange R, Flaveosin, etc., methylene blue, methylene green,
Examples include thiazine dyes such as methyl violet, oxazine dyes such as Capri Blue and Meldora Blue, 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 phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, perylene pigments such as perylene imide and perylene acid anhydride, Other examples include quinacridone pigments, azo pigments, and anthraquinone pigments. 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 used together with pigments. Furthermore, inorganic photoconductive materials include selenium, selenium-tellurium alloys, cadmium sulfide, zinc sulfide, and the like. In addition to the sensitizers listed above (spectral sensitizers), sensitizers (chemical sensitizers) are used to further increase sensitivity.
It is also possible to add. Examples of chemical sensitizers include p-chlorophenol, m-chlorophenol, p-nitrophenol, 4-chloro-m-cresol, p-chlorobenzoylacetanilide, N,N'-diethylbarbituric acid, N,N' -diethylthiobarbituric acid, 3-(β-oxyethyl)-2-phenylimino-thiazolidone, malonic acid dianilide,
Examples include 3,5,3',5'-tetrachloromalonic acid dianilide, α-naphthol, and p-nitrobenzoic acid. Further, certain electron-withdrawing compounds can be added as sensitizers that combine with the hydrazone 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-chloroanthraquinone, 1-nitroanthraquinone,
2,3-dichloro-naphthoquinone, 3,3'-dinitrobenzophenone, 4-nitrobenzalmalononitrile, phthalic anhydride, 3-(α-cyano-p
-nitrobenzal) phthalide, 2,4,7-trinitrofluorenone, 1-methyl-4-nitrofluorenone, 2,7-dinitro-3,6-dimethylfluorenone, and the like. Other additives to the photoreceptor, such as anti-curling agents for antioxidant, can be added as necessary. The hydrazone 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, the coating solution is applied onto the conductive support mentioned above, and then dried. A photoreceptor is manufactured. Coating solvents include aromatic hydrocarbons such as benzene, toluene, xylene, and monochlorobenzene, chlorinated hydrocarbons such as chloroform, dichloroethane, and trichloroethylene, ethers such as dioxane and tetrahydrofuran, and esters such as ethyl acetate and methyl cellosolve acetate. Solvents such as these 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. Example 1 Polyester film laminated with aluminum (Alpetsu 85 manufactured by Mitsubishi Plastics, film thickness
85μ, aluminum film thickness 10μ) as a support, and on top of that, the following structural formula 1 bisazo pigment shown in n-butylamine
Apply the dissolved solution to a concentration of % by weight,
It was dried to form a film of charge generating material having a thickness of 0.2 μm. Next, a hydrazone compound shown by Exemplary Compound 1 and a polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd.,
Iupilon N-6) was blended at a weight ratio of 1:1.2,
A 10% by weight solution was prepared using dichloroethane as a solvent, and this solution was applied onto the film of the carrier generating substance using an air knife and dried to form a film with a thickness of 12 μm.
A carrier moving layer was formed. The laminated electrophotographic photoreceptor produced in this way was tested using an electrostatic recording paper tester (SP manufactured by Kawaguchi Electric Co., Ltd.).
-428) was used to evaluate the electrophotographic characteristics. Measurement conditions Applied voltage -6kV, static -3 (turntable rotation speed mode; in this case
10 m/min) As a result, the half-light exposure sensitivity to white light during charging was 3.5 lux·sec, which is an extremely high sensitivity value. Furthermore, when repeated characteristic evaluations were conducted using the same apparatus, no tendency for electrophotographic characteristics to deteriorate, including light half-exposure sensitivity, was observed even after repeating 10 ³ times or more. Examples 2 to 11 The hydrazone compounds shown in Table 1 were prepared in Example 1.
A laminated photoreceptor was prepared in the same manner as in Example 1, except that the hydrazone compound was used in place of the hydrazone compound used in Example 1. The values are shown in Table 1. Initial potential (in volts) after performing the same operation for 1000 cycles, with 1 cycle of static electricity application and static neutralization (static neutralization light: white light irradiated at 400 lux for 1 second)
Table 1 shows the light half-decrease exposure sensitivity. It can be seen from Table 1 that the photoreceptor using the hydrazone compound of the present invention has excellent sensitivity and repeatability.

[Table] Example 12 A laminated photoreceptor was prepared in the same manner as in Example 1 except that a trisazo pigment having the following structural formula was used instead of the bisazo pigment used in Example 1. (however

[Formula] 633nm (He−
The energy required to reduce the given potential by half is 3.9 erg/
cm ² (633 nm) and 3.6 erg/cm ² (680 nm), making it an extremely sensitive photoreceptor. Examples 13-22 0.2 g of the trisazo pigment used in Example 12 was added to 30 ml of a dichloromethane solution in which 0.1 g of polyarylate resin (U-100 manufactured by Unitika) was dissolved, and the mixture was mixed in a paint conditioner (manufactured by Red Rebel Co., Ltd.). Dispersion was carried out for about 20 minutes, and a charge generation layer was formed on Arpet 85 using a doctor blade method so that the film thickness after drying was 0.4 μm. A charge transfer layer containing the hydrazone compound of Examples 2 to 11 was laminated on the charge generation layer to prepare a photoreceptor. The spectral sensitivities of these photoreceptors at 633 nm and 680 nm were measured in the same manner as in Example 11, and the energy required to reduce the potential by half is listed in Table 2.

【table】

[Table] It can be seen that the spectral sensitivities of all photoreceptors at both 630 nm and 680 nm are less than 5.0 erg/cm ² , which is an excellent performance. Also, the residual potential at 630nm and 680nm is reduced to 0.
The energy produced by any photoreceptor is
None exceeded 20erg/ ^cm2 . Example 23 0.3 g of the trisazo pigment used in Example 12 and 0.05 g of the polymethine dye shown in the structure below were dispersed in dichloroethane (the polymethine dye was completely dissolved), and then a 10% polyarylate resin solution was added to this dispersion. was added to the solution to give a total solids concentration of 3%, and further dispersed again in a paint conditioner for about 1 hour. The film thickness after drying the liquid created in this way is 0.3 μm.
I applied it on Arpetu 85 so that it looks like this. Next, the hydrazone compound solution used in Example 11 was applied in a layered manner onto the carrier generation layer using a doctor blade method to form a carrier transfer layer with a thickness of about 13μ. The electrophotographic photoreceptor produced in this way
When the spectral sensitivities at 780 nm, 800 nm, and 830 nm were measured in the same manner as in Example 11, they were 4.0 erg/cm ² 3.6 erg/cm ² 3.4 erg/cm ² , indicating that the photoreceptor is highly sensitive even in the near-infrared region. . Example 24 Styrene:maleic anhydride copolymer (styrene content 50 mol%) and Exemplary Compound 12 were blended at a weight ratio of 1.5:1 on an Al plate with a grained surface oxidation.
4-(4-diethylaminophenyl)-2,6-diphenyl thiapyrylium fluoroborate (thiapyrylium salt dye) at 5 x 10 ^-3 of the exemplary compound.
10% by weight plus dioxane as a solvent
A solution was prepared, and this solution was applied and dried using an S-doctor (wire bar) to prepare a single-layer photoreceptor with a film thickness of approximately 5 μm. The electrophotographic characteristics of the thus prepared photoreceptor were evaluated using the electrostatic recording paper tester described above. Evaluation conditions: applied voltage -6 kV, static 3 initial potential -480 V, light half-reduction exposure amount 6.0 lux·sec. In addition, this photoreceptor is visualized with a developer (toner), and then an alkaline processing solution (for example, 3% triethanolamine, 10% ammonium carbonate, and 20% polyethylene glycol with an average molecular weight of 190 to 210) is applied.
When treated with water, 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 is performed using this original plate, approximately 10
It was found that it can withstand printing of 10,000 copies. The optimum exposure amount (light source: halogen lamp) to obtain a visible toner image was 50 lux and 0.5 seconds. In addition, when creating the original printing plate, it was done by direct plate making without using any printing material. Example 25 Instead of the thiapyrylium salt dye used in Example 24, ε-type copper phthalocyanine was added at a weight ratio of 10 ⁻¹ to the hydrazone compound of the exemplary compound, and the phthalocyanine was sufficiently dispersed in a ball mill, and a membrane was prepared in the same manner as in Example 24. A single-layer photoreceptor with a thickness of about 4μ was created. Looking at the electrophotographic characteristics of this photoreceptor, the initial potential +
The voltage was 380V, and the light exposure was 6.2lux・sec. It was found that the printing original plate obtained by subjecting the photoreceptor thus obtained to exposure and development, alkaline treatment, and water washing in the same manner could withstand printing of about 100,000 sheets as in Example 22. For exposure, monochromatic light of 633 nm was used, and the optimum irradiation energy was about 65 erg/cm ² .

Claims (1)

[Scope of Claims] 1. A photoreceptor for electrophotography, characterized in that a hydrazone compound represented by the following general formula () is contained in a photosensitive layer formed on a conductive support. (In the formula, R ₁ is [Formula] [Formula] [Formula] [Formula], R ₂ is hydrogen, −OCH ₃ , −OC ₂ H ₅ , −CH ₃ , −C ₂ H ₅ , halogen, R ₃ is hydrogen, -CH ₃ , -C ₂ H ₅ , phenyl
R ₄ is phenyl substituted with bromo, chloro, methyl or methoxy, R ₅ is -CH ₃ , -C ₂ H ₅ , -
OCH ₃ , represents a halogen. n is 0 or 1, m is 0, 1, 2 or 3, and l is 1 or 2. 2. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains a carrier transfer substance and a carrier generation substance, and the carrier transfer substance is a hydrazone compound represented by the general formula (). 3. The electrophotographic photoreceptor according to claim 1, wherein the hydrazone compound represented by the general formula () is a compound represented by the following structural formula. (In the formula, R ₂ , R ₅ , R ₄ are the same as in the first term, and m is 0 or 1.) 4. A patent claim in which the hydrazone compound represented by the general formula () is a compound represented by the following structural formula. The electrophotographic photoreceptor according to item 1. (In the formula, R ₂ , R ₄ , R ₅ , and l have the same meanings as in the first item.) 5. Claim 1, wherein the hydrazone compound represented by the general formula () is a compound represented by the following structural formula. photoreceptor for electrophotography. (In the formula, R ₂ , R ₅ , and R ₄ are the same as in item 1, and m is 0 or 1.) 6. The electrophotographic photoreceptor according to claim 2, wherein the carrier generating substance is a trisazo pigment. 7. The electrophotographic photoreceptor according to claim 2, wherein the carrier generating substance is a bisazo pigment. 8. The electrophotographic photoreceptor according to claim 2, wherein the carrier generating substance is a phthalocyanine pigment.