JPS63253950A - 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 The present invention relates to an electrophotographic photoreceptor, and more specifically, the present invention relates to an electrophotographic photoreceptor, and more specifically, the present invention relates to an electrophotographic photoreceptor, and more specifically, a photoreceptor having the following general formula (1) 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, A is a phenyl group that may contain a substituent, a benzyl group that may contain a substituent, an alkyl group that may contain a substituent, or an allyl group, B is an alumino group, R,'
, R' is hydrogen, alkoxy group, alkyl group, halogen), m is an integer of 0 or 1, n is an integer of 1 or 2, and when n is 2, R may be the same or different groups. . R'
, R'' haphenyl group, alkyl group that may contain a substituent, benzyl group that may contain a substituent, allyl group.) Conventionally, in electrophotographic technology, the photosensitive layer of an electrophotographic photoreceptor is made of an inorganic material. Selenium, cadmium sulfide, amorphous silicon, zinc oxide, and the like are widely used, but in recent years, much research has been conducted on the use of organic photoconductive materials as electrophotographic photoreceptors.

Here are the basic properties required for an electrophotographic photoreceptor: High chargeability due to corona discharge in the dark. (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 amorphous material electrophotographic photoreceptors such as selenium and cadmium sulfide have basic properties that meet the requirements for photoreceptors, but there are manufacturing problems such as strong hostility and difficulty in film formation. It has disadvantages such as lack of flexibility and high manufacturing cost, and in the future,
In order to prevent the depletion of resources, the use of these inorganic materials whose production is limited, and furthermore, the use of photoreceptors made of organic materials instead of inorganic materials is desirable in order to prevent pollution caused by toxicity. There is.

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 than inorganic materials, can easily achieve 4 properties depending on the amount, have both positive and negative chargeability, and can be used to charge photoreceptors. It has the advantage of being easy to manufacture.

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, some improved methods have been developed, 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). However, there are still not enough materials available that satisfy the basic properties, mechanical strength, and high durability requirements of a photoreceptor as mentioned above.

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

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

Synthesis process 1゜Synthesis process 2゜Synthesis process 3-1 Synthesis process for the compound of general formula (1) 3-2 -> Compound of general formula (I) (几, B', R'', A, n and m are synonyms as above, and X represents a halogen. , dioxane, benzene, etc.) to easily obtain the target compound Ia.

and Ic can be obtained. Synthesis of 3-1 is carried out in the same manner. In the case of 3-1, a hydrazine compound is often used in the form of a salt, and in this case, an alkaline compound such as sodium acetate is used as a catalyst.

Synthesis step 2 can be easily obtained by a conventional Pils-Meyer reaction. It is necessary to use two or more amounts of the Vilsmeier reagent.

The final stage of synthesis step 3-2 can be achieved by dissolving the halogen compound and the compound of Ic in dimethyl sulfoxide, and adding thereto an aqueous solution (or alcohol solution) in which caustic soda or the like is dissolved.

This reaction is usually completed at room temperature, but may be heated if necessary.

Each of these synthesis steps is easy to perform, and the yield is over 70% in all steps, including the availability of raw materials.
There are no problems with synthesis.

Specific examples of the hydrazone compound useful in the present invention represented by the general formula (I) include those having the following structural formula.

Exemplary compound CH.

OCHs Specific synthesis examples of some of these exemplified compounds will be described below.

Synthesis Example 1 (Illustrative Compound J162) Equimolar moles of acetate 7e7 and phenolic hydrazine were dissolved in ethanol, a small amount of glacial acetic acid was added, and the mixture was heated under reflux for 20 minutes.
By carrying out this process for some time, yellow-orange acetophenone and phenylhydrazone are obtained.

By adding 2 equivalents of dimethylformamide and phosphorus oxychloride to the hydrazone compound thus obtained, Q
1.3-diphenyl-4-formyl-pyrazole (melting point 149.5-151.0°C) is obtained. Note that ethanol was used as the recrystallization solvent.

Equimolar amounts of the pyrazole compound and diphenylhydrazone hydrochloride thus obtained were added, potassium acetate was further added as a slightly excess reaction catalyst, and the mixture was heated and refluxed in ethanol for 2 hours to obtain exemplified compound 2 ( Melting point 114
．． 0 to 115.5°C). Note that ethanol was used as the recrystallization solvent.

The synthesis yield of each of these steps is 87.5 zhong), 96.4 ＠)
, 78.2 (%), showing good values in each process.

Synthesis Example 2 (Exemplary Compound Point 5) P-methoxyacetophenone and phenylhydrazine were added in equal moles to prepare P-methoxyacetophenone-722hydrazone t-il.

Next, this hydrazone compound was subjected to a Bils-Meyer reaction with phosphorus oxychloride and dimethylformamide.
-Phenyl-3-(P-methoxyphenyl)-4-formylhyrasol (MLa 141°5-143.0°C) is obtained. Note that ethanol was used as the recrystallization solvent.

Exemplary compound AAL5 (melting point 135.0-136.5°C) was prepared in exactly the same manner as in Synthesis Example 1 using the pyrazole compound thus obtained and diphenylhydrazone hydrochloride.
get.

The synthesis yields of each of these steps were 86.8 (h) and 95.4 (
%), 79.5%, showing good values in each process. The IR (KBr tablet method) spectrum of this compound is shown in FIG.

Synthesis Example 3 (Exemplary Compound Point 6) Exemplary Compound 6 (melting point 112) was prepared by dissolving equimolar amounts of the formylated product obtained in Synthesis Example 2 and phenyl-methyl-hydrazine in ethanol and heating under reflux for 2 hours. ~11
3.5°C).

Synthesis Example 4 (Exemplary Compound A17) P-dimethylaminoacetophenone-phenylhydrazone (14 points, 156-158.5°C) is obtained from P-dimethylaminoacetonephenone and 7-enylhydrazine.

Then, in the same manner as in Synthesis Example 1, yellow-orange 1-phenyl-3
-(P-dimethylaminophenyl) -4-formyl-
A pyrazole (melting point i 2 i, o-122.5° C.) is obtained.

The pyrazole compound thus obtained and N,N-diphenylhydrazine hydrochloride were added to equimolar ethanol, a slight excess of sodium acetate was added, and the mixture was heated under reflux for 2 hours to produce a pale yellow needle-like exemplary compound. A17 ([Point 189~
191.5°C). Note that ethyl acetate was used as the recrystallization solvent.

Synthesis Example 5 (Exemplified Compound A18) Exemplified Compound A18 (melting point 170-171.5°C) is obtained by using phenyl-methylhydrazine in place of diphenylhydrazine hydrochloride in Synthesis Example 4. The recrystallization solvent is 1 s.
o-propyl alcohol was used.

Other pyrazole ring-containing hydrazone compounds can also be easily synthesized according to the above synthesis example.

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 pyrazole ring-containing hydrazone compounds as electrophotographic photoreceptors.

For example, a photoreceptor (sensitized) is made by dissolving or dispersing a hydrazone compound and a sensitizing dye in a binder, with the addition of a chemical sensitizer or an electron-absorbing compound as necessary, on a conductive support. dye-added photoreceptor). Alternatively, the hydrazone compound of the present invention can be used as a charge transfer substance in a photoreceptor (function valve 1'1ffl photoreceptor) in which a substance with high charge (carrier) generation efficiency and a substance with high carrier transfer efficiency are combined and their respective functions are shared. use Broadly divided into 2
It can be applied to any of the two photoreceptors.

When producing a photoreceptor using the hydrazone compound of the present invention, a metal cylinder such as aluminum, a metal plate, a vapor-deposited film such as aluminum, a laminated film, a conductive processed film, a conductive support such as paper, etc. On top, it is coated with the help of a film-forming binder.

Various compounds can be used as the film-forming binder depending on the field of use. In other words, in the field of photoreceptors for copying, ■ Excellent film properties.

■ Large volume resistance value.

■ Good solubility.

■ High surface rigidity.

■ Excellent electrophotographic properties (especially low residual potential).

■ High transmittance.

Film-forming binders having the following properties are preferred.

Specifically, preferred are noryl resin, methacrylic resin, polystyrene resin, polyvinyl acetal TT resin, polysulfone resin, polycarbonate resin, acetic acid vinylcrotonic acid copolymer resin, polyphenylene oxide resin, polyester resin, alkyd resin, polyarylate resin, etc. .

These may be used singly or as a copolymer, or two types of polymers may be used.
It is possible to use a mixture of 1i1i or more. Among them, resins such as Noryl, polyphenylene oxide, polycarbonate, and polyarylate resins have a volume resistivity of 10130.
The above binder+i film properties, electrophotographic properties, etc. are excellent.

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 0.5 or less to the organic photoconductor. A disadvantage arises in that the amount of photoresist precipitates on the surface of the photosensitive layer, and when it increases by more than 5 times, sensitivity decreases. In addition to the above-mentioned properties, alkaline solubility is particularly required for use in planographic printing plates. Alkali solubility refers to water or alcoholic alkaline solvents (
It is characterized by having an acidic group, such as an acid anhydride group, a carboxyl group, a phenolic hydroxyl group, a sulfonic acid group, a sulfonamide group, or a sulfonimide group, which is soluble in a mixture (including mixed systems).

It is preferable that the lithographic binder 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.

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

Next, in the polymeric film-forming binder used, the photosensitive layer is hard and weak in mechanical properties such as tension, bending, and compression, and in order to improve these properties, a substance that gives layering properties is added. It is also necessary when adding.

These substances include phthalates (e.g. DO
P, DBP, DIDP, etc.), phosphate esters (e.g., t
TcP, TOP) 'If: d) sebacic acid ester,
Examples include 7-dipic acid ester, epoxidized soybean oil, nitrile rubber, and chlorinated hydrocarbons.

In addition, the ratio of the substances that provide these layering properties to the polymerizability, film-forming properties, and binder is preferably between 0.1% and 20% by weight, and less than 0.1% will not improve the property. This is insufficient; if it exceeds 20%, the potential characteristics will deteriorate.

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, rotamine B, rotamine 3B, and acridine red. Xanthene dyes such as B1; acridine dyes such as Acridine Orange 2G, Acridine Orange R, and Frapeosin; thiazine dyes such as Methylene Blue, Methylene Green, and Methyl Violet; These include oxazine dyes, 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 perylimide and perylenic anhydride, and others. These include quinacridone pigments, azo pigments, anthraquinone pigments, and quinone 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-
10 Lophenol, p-nitrophenol, 4-chloro-m-cresol, p-chlorobenzoylacetanilide, N,N'-diethylbarbylic acid, N,N'-diethylthiobarbylic acid, 3-( β-oxyethyl)
Examples include -2-phenylimino-thiazolidone, malonic dianilide, 3,5°31, s/-tetrachromated malonic dianilide, α-naphthol, I)-di)benzoic 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 this electron-withdrawing substance include 1,4-bis(p
-cyano-β-alkoxycarbonylvinyl)benzene, 1-nitroanthraquinone, 2.3-dichloro-naphthoquinone, 3.3'-dinitrobenzphenone, 4
-Nitrobenzalmalonenitrile phthalic anhydride, 3-(
a-cyano-p-nitrobenzal) phthalide, 2,4.
Examples include 7-dolinitrofluorenone, 1-methyl-4-nitrofluorenone, 2°7-sinitro-3,6-dimethylfluorenone, α-p-nitrophenyl-β, and β-dicyanoethylene.

Other additives such as antioxidants and ultraviolet absorbers may be added to the photoreceptor as required.

The hydrazone 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 mixed with benzene, toluene, xylene, etc. as the conductive coating solvent mentioned above. , aromatic hydrocarbons such as monochlorobenzene, dioxane, methyl cellosolve acetate, a mixture of two or more solvents such as dichloroethane, alcohols, acetonitrile, N,N-dimethylformamide, methyl ethyl ketone, etc. as necessary. Additional solvents can be used.

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 10μ) was used as a support, and one weight of bisazo pigment represented by the following structural formula was added to n-butylamine on the support. %
A solution dissolved at a concentration of 2 μm was applied and dried to form a film of the charge generating substance with a thickness of 2 μm.

Next, the hydrazone compound shown in exemplified compound point 6 and the polyarylate resin (U-polymer manufactured by Unitika) were added to 121.
15 by using dichloroethane as a solvent.
This solution was applied onto the film of the carrier generating substance using a squeegee doctor to form a carrier transfer layer having a dry thickness of 16 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 -6KV Static A3 As a result, the light half-reduction exposure sensitivity to white light during charging is 2.1
It showed a very high sensitivity value of lux·sec.

Furthermore, repeated evaluation of the characteristics using the same apparatus revealed no tendency for electrophotographic characteristics to deteriorate, including the optical half-reduced H photosensitivity, even after the evaluation was repeated 103 times or more.

Examples 2 to 6 RW 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. Under the measurement conditions, the optical half-reduction exposure E- (lux/second) and the 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 at 400 lux with white light)
．． Table 1 shows the initial potential vO (volt) and optical half-exposure sensitivity E+ (lux/sec) after performing the same operation for 1000 cycles, with 2 seconds of irradiation as one cycle.

From Table 1, it can be seen that the photoreceptor using the hydrazone compound of the present invention has excellent sensitivity and green-reflection characteristics.

8εTT 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-N
When the spectral sensitivity at 670 nm (light emitting diode) and 670 nm (light emitting diode) was measured using a monochromator, the energy required to reduce the potential by half was e, s erg/J (6
33 nm), 5. It was a photoreceptor with extremely high sensitivity of Oerg/apl (660 nm). The initial potential is 1015
(Bolt). (Applied voltage knee 5.5 KV) Examples 8 to 12 Add 0.22 of the trisazo pigment used in Example 7 to 30 of a dichloromethane solution in which 0.19 of polyarylate resin (U-100 manufactured by Unitika) was dissolved. A charge generation layer was formed on Sialvet 85 by the Dr. Plaid method by dispersing it in Paint Condition Siloner (manufactured by Red Level Co., Ltd.) for about 20 minutes so that the film thickness after drying was 0.4 μm.

A charge transfer layer containing the hydrazone compound of Examples 2 to 6 was laminated on the charge generation layer to prepare a photoreceptor.

The spectral sensitivities of these photoreceptors at 633 and 660 nm were measured in the same manner as in Example 9, and the energy required to reduce the potential by half is shown in Table 2.

Table 2 Example 13 On a grained surface oxidized M plate, styrene; ethyl methacrylate: methacrylic acid (styrene: ethylene methacrylate = 3; 1 weight ratio, acid value 180) and Exemplified Hardware Shop 26 were mixed in 1. 5:1 weight ratio, and 4-(p-diethylaminophenyl)-2,6-p-)lyltheapyrylium perchlorate [tapyrylium salt dye] was added to the 5XIO-' weight ratio of the exemplary compound. In addition, a 10% by weight solution was prepared using dioxane as a solvent, and this solution was coated with a squeegee doctor and dried to prepare a single layer type photoreceptor having a film thickness of 5 μm.

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 430 (Volt incident light half-reduction exposure amount 7.5 (lux seconds)).

In addition, this photoreceptor is visualized with a developer (toner), and then an alkaline processing solution (for example, 3% triethanolamine 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 optimal exposure was 1 second at 150 lux.

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

Example 14 δ for j5 of the thiapyrylium salt dye used in Example 13
Steel phthalocyanine was added at a weight ratio of 10% of the hydrazone compound as an example compound, and the phthalocyanine was sufficiently dispersed in a ball mill to prepare a single-layer photoreceptor having a film thickness of 4 μm in the same manner as in Example 13.

90 (volts), half light exposure fi3. o (looks/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.

Incidentally, for exposure, monochromatic light of 633 nm was used, and the optimum irradiation energy was about 120 erg.

[Brief explanation of the drawing]

The EiT1 diagram is an infrared absorption spectrum (KBr tablet method) of the hydrazone compound corresponding to Synthesis Example 1 of the present invention.

Claims (1)

[Scope of Claims] (1) An electrophotographic photoreceptor characterized in that a hydrazone 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 is a phenyl group that may contain a substituent, a benzyl group that may contain a substituent, an alkyl group that may contain a substituent, or an allyl group, and R is an alkoxy group, an alkyl group, ▲ mathematical formula, chemical formula , tables, etc. ▼ group, hydrogen, halogen, R', R'' are hydrogen, alkoxy group, alkyl group, halogen, m is an integer of 0 or 1, n is an integer of 1 or 2, When n is 2, R may be the same or different groups. R″′ and R″″ are a phenyl group, an alkyl group that may contain a substituent, a benzyl group that may contain a substituent,
It is an allyl group. (2) The electrophotographic photoreceptor according to claim 1, wherein the hydrazone 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, A, R, m, and n are synonymous with the first term.) (
3) Claim 1, wherein the hydrazone 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.▼ (In the formula, B is a methyl group or an ethyl group, and A and m are the first
Synonymous with term. (4) The electrophotographic photoreceptor according to claim 1, wherein the hydrazone 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 formulas, R''', R'''', A, and m are synonymous with the first term.) (5) The photoreceptor transfers a carrier transfer substance and a carrier generation substance. and the carrier transfer substance is a hydrazone compound represented by the general formula (I).(6) The electrophotographic photoreceptor according to claim 1, wherein the carrier-generating substance is a trisazo pigment. The electrophotographic photoreceptor according to claim 5. (7) The electrophotographic photoreceptor according to claim 5, wherein the carrier-generating substance is a bisazo pigment. (8) The electrophotographic photoreceptor according to claim 5, wherein the carrier-generating substance is a phthalocyanine pigment. 2. The electrophotographic photoreceptor according to item 1.