JPS60147742A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity and durability by incorporating a specified hydrazone compd. in a photosensitive layer. CONSTITUTION:A photosensitive layer formed on a conductive substrate contains a hydrazone compd. represented by formula I R1 is optionally substd. alkyl or aryl; R2 is H, alkyl, halogen, or alkoxy; R3 is H or alkyl; and R4, R5 are each H, halogen, optionally substd. alkyl or alkoxy. Said compd. is, preferably, one of compds. represented by formulae II-V in which R2, R4, and R5 are same as before. A photosensitive body contains a carrier transfer material and a carrier generating material, and said hydrazone compd. of formula I is used as the carrier transfer material, and carrier generating materials, such as trisazo pigments, bisazo pigments, phthalocyanine pigments, etc., are preferably used. Such a hydrazone compd. is dispersed into a binder together with a sensitizing dye, etc., or it is added alone to a functionally separated type photosensitive layer to form the photosensitive body. The photosensitive body using such as hydrazone compd. has high sensitivity and high durability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoreceptor for electrophotography, and more particularly, the present invention relates to a photoreceptor for electrophotography, and more specifically, the present invention relates to a photoreceptor having the following general formula σ in a photosensitive layer formed on a conductive support.
) The present invention relates to an electrophotographic photoreceptor containing a hydrazone compound represented by:

(In the formula, R1 is an alkyl group that may contain a substituent, an aryl group that may contain a substituent, - is hydrogen, an alkyl group, a halogen, an alkoxy group, hydrogen, an alkyl group, R4, R5 are (represents hydrogen, halogen, an alkyl group, or an alkoxy group which may contain a substituent.) Conventionally, in electrophotographic technology, the photosensitive layer of an electrophotographic photoreceptor contains inorganic substances such as selenium, cadmium sulfide, amorphous silicon, Zinc oxide and the like are widely used, but in recent years there has been much research into using 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; (2) The charge caused by corona charging has little attenuation in the dark. (3) The charge quickly dissipates when irradiated with light. (4) There is little residual charge after irradiation with light. etc. It is.

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. It has drawbacks such as a lack of flexibility and high production costs, and in the future, it will be necessary to use these inorganic substances, which have limited production, to deplete resources, and even become toxic. In view of the pollution caused by photoreceptors, it is desired to use photoreceptors made of organic rather than 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 advantages such as being easy to use.

By the way, 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, flexibility, solubility, or adhesive properties. In addition, polyvinylcarbazole is sensitized with pyrylium salt dye (Japanese Patent Publication No. 48-25658), polyvinylcarbazole and 2,4,7-dolinitrofluorenone are sensitized (US Pat. No. 34,842B?), etc. Although some improvements have been made, it has not yet been possible to find one that fully satisfies the basic properties, mechanical strength, high durability, etc. required of a photoreceptor as listed above.

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

The hydrazone compound of the general formula σ) related to the present invention is usually synthesized by the following synthesis process.

First, a ketone (113 is an alkyl group) derivative represented by the general formula (-) or an aldehyde (IL3 is hydrogen) derivative and a phenylhydrazine visiting conductor represented by the general formula (b) are mixed in a suitable solvent (e.g. alcohol, ethyl acetate). ), if necessary, an alkaline compound (for example, sodium bicarbonate, sodium acetate, potassium acetate) is added as a catalyst and stirred under heating to obtain a hydrazone compound represented by the general formula (C).

The reaction formula is as follows.

General formula (,) General center b) General formula (C) (R□, R2, R3, R4, 几 in the above reaction formula are synonyms with general formula σ) Next, the hydrazone compound obtained in this way The hydrazone compound of the present invention can be obtained by reacting p-methylbenzyl halide with p-methylbenzyl halide in an alkali catalyst.

The reaction formula is as follows.

(In the above reaction formula, R1, R2, R3, R4, and Ra are synonymous with the general formula α), and x represents a halogen. ) Specific examples of the hydrazone compound useful in the present invention represented by the general formula 〇) include those having the following structural formula.

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

Synthesis Example 1 (Exemplary Compound 117) Diethylaminobenzaldehyde 189 (0.1 mol
e) and phenylhydrazine 12F (0,11 mole
) was heated to reflux in ethanol with a melting point of 121-122.
p-dietheraminopenzaldehyde phenylhydrazone 26, Of is obtained at 5°C.

Next, p-diallylaminobenzaldehyde-phenylhydrazone 5.4 f (0,02(2)Ie)↓ was added to p-methylbenzyl chloride 3.0 f (0,021 r
Nole) and a 3N aqueous sodium hydroxide solution 10-10°C, heat and stir to remove the ethyl acetate soluble content, then ethyl acetate is distilled off, and the residue is recrystallized in 40cc of ethanol with a melting point of 108-109.5. 5.7 ttl of yellowish crystals are obtained. Furthermore, this compound!几(KBr
When the tablets were measured, it was found that the absorption at 3300 cm (3300 cm) had disappeared based on the -NH- absorption of the raw material p-diethylaminobenzaldehyde-phenylhydrazone.

Synthesis Example 2 (Exemplary Compound Na24) In the same manner as in Synthesis Example 1, p-dibenzylaminobenzaldehydophenylhydrazone (melting point 191-192.5
C) and p-methylbenzyl chloride to obtain a yellow-orange powder with a melting point of 152.5-154.0C. The resolute solvent used was a mixed solvent of ethanol and ethyl acetate.

Synthesis Example 3 (Exemplary Compound Magnetism 21) p-diarylaminobenzaldehyde-phenylhydrazone (melting point 63.5-65°C) was prepared in the same manner as in Synthesis Example 1.
and p-methylbenzyl chloride to give a melting point of 96.
．． Yellow-orange granular crystals with a temperature of 0 to 97.5°C were obtained. Methanol was used as the resolvent.

Synthesis Example 4 (Exemplary Compound Dynamic Compound 10) The same procedure as in Synthesis Example 1 was carried out, with a melting point of 122°C to 123°C.
A yellowish powder was obtained at 5°C.

In the above synthesis example, the final compound was synthesized in a system using an aqueous alkaline solution, but it is also possible to synthesize it by reacting at room temperature using dimethyl sulfoxide as a solvent. be.

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. A photoreceptor is formed by dissolving or dispersing a photoreceptor on a conductive support, or a photoreceptor in the form of a laminated structure consisting of a carrier generation layer and a carrier transfer layer with extremely low charge carrier generation efficiency is placed on a factory conductive support. The present hydrazone compound is dissolved or dispersed in a binder with the addition of a chemical sensitizer or an electron-withdrawing compound if necessary on a carrier generation layer mainly composed of a sensitizing dye or pigment, and then a carrier transport layer is formed. 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, a polymer film is formed on a support such as a metal cylinder, a metal plate, a conductive treated paper, or a conductive treated plastic film. into a film with the help of a binding agent.

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 light-sensitive layer film of about -1.

Various types of polymeric acid 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, acid vinylcrotonic acid copolymer resin,
Polyphenylene oxide resins, polyester resins, alkyd resins, polyacrylate resins, etc. are preferred.

These can be used alone or in the form of a copolymer of one type or a mixture of two or more types.

Among them, resins such as polystyrene, polyphenylene oxide, polycarbonate, polyarylate resin, etc., and binders having a volume resistivity of 100 or more have excellent film properties, potential properties, etc.

The amount of these binders added to the organic photoconductor is 0.2 to 20 times by weight, preferably 0.5 to 5 times, and when the amount is 0.5 or less, the organic photoconductor becomes This has the disadvantage that it precipitates from 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.

Binder resin with a high acid value is easily resistant to alkaline solvents: J Easily soluble or swells.

These bonded resins include, for example, styrene: maleic anhydride copolymer, vinyl acetate maleic anhydride, vinyl 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.

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

These substances include phthalates (e.g. DO
PXDBP, DIDP, etc.), phosphate ester (9Al
Examples include TCP, TOP) sebacic acid ester, adipic acid ester, epoxidized soybean oil, nitrile rubber, and chlorinated hydrocarbons. In addition, the ratio of these substances imparting plasticity to the polymerizable film-forming binder is preferably between 0.1% and 20x6 by weight; less than 0.1x is insufficient for improvement. , 20
If it is more than X, the potential characteristics will be deteriorated.

Next, the sensitizing dyes added to the photosensitive layer include triphenylmethane dyes such as methyl violet, crystal violet, ethyl violet, night blue, and Victoria blue, erythrosine, rhodamine B1 rhodamira 3B, and acridine red. Representative examples include xanthen dyes such as B1, acridine orange 20, acridine orange 20, flaveosin, etc.

Acridine dye, methylene blue, methylene green,
Examples include thiazine dyes such as methyl violet, oxazine dyes such as fog blue and melt rub, other cyanine dyes, styryl dyes, biryllium 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 hydrothermal solution, Other examples include quinacridone pigments, azo pigments, and anthraquinone pigments.

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.

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+''-diethylthiobarbylic acid, 3-(B- oxyethyl)
-2-phenylimino-thiazolidone, malonic acid dianilide, 3.5.3', 5'-tetrachloromalonic acid dianilide, α-naphthol, p-nitrobenzoic acid and the like.

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 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) lid +) ), 2
, 4.7-)! J=trofluorenone, 1-methyl-
4-nitrofluorenone, 2,7-sinitro 3,6-
c) Examples include I-methylfluorenone.

Other additives to the photoreceptor, such as antioxidants and anti-curl agents, 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, and the coating solution is coated on the conductive support as 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 alone or in combination
A mixed solvent of more than one species or a solvent such as alcohol, acetonitrile, N,N-dimethylformamide, or methyl ethyl ketone may be added as necessary.

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 (Alpet 85 manufactured by Mitsubishi Plastics, film thickness 85μ, aluminum film thickness 1oμ) was used as a support, and a bisazo pigment represented by the following structural formula was added to n-butylamine at 1% on the support. 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 hydrazone compound shown by Exemplary Compound Magnetic Motion 7 and a polyarylate resin (U-polymer manufactured by Unitika) were mixed in a ratio of 1:1.
IO using dichloroethane as a solvent.
A solution of X was prepared, and 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 12 μm.

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

Measurement conditions: Applied voltage -6KV, static level 3 As a result, the light half-reduction exposure sensitivity for white light during charging is 3.0
It showed a very high sensitivity value of lux·sec.

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

Examples 2 to 8 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. Half-light exposure ffkB'r (lux seconds) and initial potential ■ under measurement conditions. (in 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 optical half-exposure sensitivity J- (in lux/seconds) after performing the same operation for i 000 cycles, where one cycle is irradiation (seconds irradiation).

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

Example 9 A laminated photoreceptor was prepared in exactly the same manner as in Example 1 except that a triazo pigment having the following structural formula was used in place of the bisazo pigment used in Example 1.

The 6'33 nm (He-
When the spectral sensitivity at 670 nm (Ne laser) and 670 nm (light emitting diode) was measured using a monochromator,
The energy required to reduce the potential by half is 5.6 erg/cII
(633nm), 5.2erg/al (670nm
) and was an extremely sensitive photoreceptor.

Examples 10 to 16 Triazo pigment ◇, 2f used in Example 9 was added to a dichloromethane solution 3〇 in which 0.12% of polyarylate resin (tJ-100 manufactured by Unitika) was dissolved, and paint conditioner (manufactured by Red Level Co., Ltd.) was added. ) for about 20 minutes, and a charge generation layer was formed on Alpet 85 by the Dr. Plaid method to a dry film thickness of 0.4 μm.

A charge transfer layer containing the hydrazone compound of Examples 2 to 8 was laminated on the charge generation layer to prepare a photoreceptor.

The spectral sensitivities of these photoreceptors from 633n to 670 am 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 17 5% by weight solution of copolymer nylon (CM-8000 manufactured by Unitika) in which polymethine dye 0.1F shown in the following structure was dissolved in a mixed solvent of ethanol and methyl alcohol 30
- to make a homogeneous solution.

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

Next, hydrazone compound 2f of Exemplified Compound Ugly 24 was added to styrene resin (Styron-85' manufactured by Mitsubishi Monsanto) 1.
5 and polybutyl acrylate resin (manufactured in-house) o,
sr was dissolved in 20 m of toluene, and this solution was coated in a layered manner on the above carrier generation layer by the Doctor Plaid method to form a carrier transfer layer of about 10 μm.

780 nm, 8
When the spectral sensitivity at 20 nm and 8 Onm was measured in the same manner as in the example, it was 12 erg,/al (780 nm),
10 erg/d (820 nm), 8 erg/eA (
840 nm), indicating that the photoreceptor is highly sensitive even in near-infrared light.

Example 18 Styrene: ethyl methacrylate: methacrylic acid (styrene: ethylene methacrylate weight ratio 321, acid value 170) and exemplified compound N were placed on a grained surface oxidized board.
a7 at a weight ratio of 1.5:1 and 1.4-(p-diethylaminophenyl)-2,6-jep)! J Luciapyrillium perchlorate (thiapyrylium salt pigment)
of the exemplified compound at a weight ratio of 5 x 10 to form a 10% by weight solution using dioxane as a solvent.This solution was coated with a squeegee doctor and dried to form a single-layer photosensitive film with a film thickness of 5μ. created a body.

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

Evaluation conditions: applied voltage -6KV, static -3 initial potential 370 (volts), light half-reduction exposure amount 8.0 (lux seconds)
Met.

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

It was found that when offset printing was performed using Jin's original plate, 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 501 ux and 1 second.

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

Example 19 A 7-layer photoreceptor having a film thickness of 4 μm was prepared in the same manner as in Example 18 by adding the hydrazone compound at a weight ratio of ION and sufficiently dispersing phthalocyanine in a ball mill.

When looking at the electrophotographic characteristics of this photoreceptor, it was found that the initial potential was 420 (volts) and the light half-reduced exposure amount was 7.2 (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.

Claims (1)

[Scope of Claims] (1) An electrophotographic photoreceptor characterized in that a hydrazone compound represented by the following general formula (0) is contained in a photosensitive layer formed on a conductive support. (In the formula, R□ is an alkyl group that may contain a substituent, an aryl group that may contain a substituent, R2 is hydrogen, an alkyl group, a halogen, an alkoxy group, hydrogen, an alkyl group, R4,85 (2) The hydrazone compound represented by the general formula α) is a compound represented by the following structural formula. 1
The electrophotographic photoreceptor described in . (In the formula, R2, 几, and R5 have the same meanings as in claim 1) (3) The hydrazone compound represented by the general formula (f) is a compound represented by the following structural formula, Electrophotographic photoreceptor. 5 (wherein R2, R4, and Rs have the same meanings as in paragraph 1) (4) The electrophotography according to claim 1, wherein the hydrazone compound represented by the general formula α) is a compound represented by the following structural formula. ! Photoreceptor. (wherein a□t R4 and R5 have the same meanings as in claim 1) (5) The electron according to claim 1, wherein the hydrazone compound represented by the general formula α) is a compound represented by the following structural formula. Photographic photoreceptor. (In the formula, R2, R4, and Rs have the same meanings as in the first term) (6) The photoreceptor contains a carrier transfer substance and a carrier generation substance, and the nuclear carrier transfer substance is a hydrazone compound represented by the general formula 〇). An electrophotographic photoreceptor according to claim 1. (7) The electrophotographic photoreceptor according to claim 6, wherein the carrier generating substance is a triazo pigment. (8) The electrophotographic photoreceptor according to claim 6, wherein the carrier generating substance is a bisazo pigment. (9) The electrophotographic photoreceptor according to claim 6, wherein the carrier generating substance is a phthalocyanine pigment.