JPS62120346A - Novel distyryl compound and photosensitive substance containing the same - Google Patents

Abstract

NEW MATERIAL:A compound of formula I (R1, R2 are H, alkyl, aryl, aralkyl, heterocyclic, or incorporate to form a ring; R3 is alkyl, aralkyl, alkoxy, aryl, formula II; R4 is H, alkyl, alkoxy, aralkyl, aryl). USE:An electric charge transfer material. The photo-sensitive substance containing the same has high sensitivity, reduced fatigue deterioration by residual potential and repeated use, high stability to light with duration. PREPARATION:The reaction of a phosphorus compound of formula III [X is -P<+>(R5)3Y<-> (R5 is alkyl, aryl; Y is halogen ion), PO(OR6)2 (R6 is alkyl)] with a diformyl compound of formula IV is carried out in an inert solvent in the presence of a condensation reagent to give the compound of formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel distyryl compound and a photoreceptor using the distyryl compound as a charge transport material.

Conventional technology In general, in electrophotography, the surface of the photosensitive layer of a photoreceptor is charged and exposed to form an electrostatic latent image, which is developed with a developer to make it visible, and the visible image is transferred directly to the photoreceptor. A direct method in which the visible image on the photoconductor is transferred onto a transfer paper such as paper and the transferred image is fixed on a transfer paper such as paper to obtain a copy image. The electrostatic latent image is transferred onto transfer paper, and the electrostatic latent image on the transfer paper is developed and
A fixing latent image transfer method is known.

Conventionally, it has been known that inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide are used as photoconductive materials to form the photosensitive layer of photoconductors used in this type of electrophotography. There is. These photoconductive materials have many advantages, such as being able to be charged to an appropriate potential in the dark, having little charge dissipation in the dark, and being able to quickly dissipate charge when irradiated with light. It has various drawbacks as follows. For example, in a selenium-based photoreceptor,
It is expensive to manufacture, and must be handled with care as it is sensitive to heat and mechanical shock.Also, cadmium sulfide photoreceptors and zinc oxide photoreceptors do not provide stable sensitivity in humid environments. The dye added as a sensitizer causes charging deterioration due to corona charging and photobleaching due to exposure, so it has the disadvantage that stable characteristics cannot be provided over a long period of time.

On the other hand, although all materials including polyvinylcarbazole are excellent in terms of film formability and light weight, they still lack sufficient sensitivity and
It is inferior to inorganic photoconductive materials in terms of durability and stability against environmental changes.

Problems to be Solved by the Invention In contrast, with low molecular weight organic photoconductive compounds, the physical properties or electrophotographic properties of the film can be controlled by selecting the type of binder used together, the composition ratio, etc. However, since it is used in combination with a binder, high compatibility with the binder is required.

However, 45-bis(P-diethylaminophenyl) described in U.S. Patent No. 3.18'1447
-L3,4-oxadiazole has low compatibility with binders and tends to precipitate crystals. US Patent No. λ82
Although the diarylalkane derivatives described in Japanese Patent No. 0,989 have good compatibility with binders, sensitivity changes occur when used repeatedly. Also, JP-A-5
The hydrazone compound described in Publication No. 4-59143 ゛ -. . . 71-. - has relatively good initial sensitivity and residual potential characteristics, but the sensitivity decreases when used repeatedly.
It has the disadvantage of poor durability.

Means for Solving the Problems The present invention provides a novel distyryl compound useful as a charge transport material, and a durable compound with high sensitivity, low residual potential and fatigue deterioration due to repeated use, and good stability against light. The purpose is to provide an excellent photoreceptor.

The present invention is based on the general formula: [In the formula, R1 and R2 represent hydrogen, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group, and each group may have a substituent. R1 and R2 may be combined to form a ring, except when R1 and R2 are hydrogen at the same time. R3 is an alkyl group, an aralkyl group, an alkoxy group,
It represents an aryl group, and each group may have a substituent. R3 may be a group represented by the following formula [■].

[In the formula, R1, R2, and R4 have the same definition as [1]] R4 represents hydrogen, an alkyl group, an alkoxy group, an aralkyl group, or an aryl group, and each group may have a substituent.

] The present invention relates to a distyryl compound represented by

Furthermore, the present invention relates to a photoreceptor characterized by containing a distyryl compound represented by the following general formula [■] as a charge transport material.

General formula: In formula C, R1 and R2 represent hydrogen, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group, and each group may have a substituent. R1 and R2 may be combined to form a ring, except when R1 and R2 are hydrogen at the same time.剮3 is an alkyl group, an aralkyl group, an alkoxy group,
It represents an aryl group, and each group may have a substituent. R3 may be a group represented by the following formula [■].

[In the formula, R1, R2, and R4 have the same meanings as in (1)] R4 represents hydrogen, an alkyl group, an alkoxy group, an aralkyl group, or an aryl group, and each group may have a substituent.

] In the distyryl compound represented by the general formula [1] of the present invention, λ! And R2 is preferably an aryl group in which either one has a substituent. R3 is preferably an alkyl group or an aryl group having a substituent, and R4 is preferably hydrogen, an alkyl group, or an alkoxy group. These are particularly excellent in solubility and sensitivity.

Preferred specific examples of the distyryl compound represented by the general formula [I] of the present invention include those having the following structural formula, but are not limited thereto.

(Margin below) The distyryl compound represented by the general formula (1) of the present invention can be easily produced by a known method.

The distyryl compound represented by the general formula [1] is, for example, a triphenylphosphonium group represented by the following general formula (In), a trialkylphosphonium salt, or -PO(ORs)
Indicates a dialkyl phosphite group represented by t. R5 represents an alkyl group or an aryl group, Y represents a halogen ion, and R6 represents an alkyl group. It can be obtained by reacting a phosphorus compound represented by the following general formula [■] with a diformyl compound represented by the following general formula: (R3, R4 have the same meaning as ('I')).

The phosphorus compound represented by the general formula (III) can be easily produced by heating the corresponding halomethyl compound and triarylphosphine, trialkylphosphine, or doriatrukyl phosphite directly or in a solvent such as ≠ luene xylene. I can do it.

Inert solvents such as hydrocarbons, alcohols, and ethers are suitable as reaction solvents in the above method for synthesizing distyryl compounds, such as methanol, ethanol, impropatol, butanol, 2-methoxyethanol, L2
-dimethoxyethane, bis(2-methoxyethyl) ether, dioxane, tetrahydro7rane, toluene, xylene, dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, 13-dimethyl-2
-imidazolidinone and the like. Among them, polar solvents such as N,N-dimethylformamide and dimethylsulfoxide are preferred.

As the condensing agent, alcoholades such as caustic soda, caustic potash, sodium amide sodium hydride and sodium methylate, potassium-(-butoxide) are used.

The reaction temperature can be selected from a wide range of about 100°C to about 100°C depending on the stability of the solvent used with respect to the condensing agent, the reactivity of the condensation components, and the reactivity of the condensing agent.
It is 0°C to 80°C.

Examples of structures of photoreceptors using the distyryl compound of the present invention are schematically shown in FIGS. 1 to 5.

Figure 1 shows a photoreceptor in which a photosensitive layer (4) containing a photoconductive material (3) and a charge transporting material (2) as a binder is formed on a substrate (1). The distyryl compound of the present invention is used.

FIG. 2 shows a functionally separated photoreceptor having a charge generation layer (6) and a charge transport layer (5) as photosensitive layers.
A charge transport layer (5) is formed on the surface of 6).

The distyryl compound of the present invention is blended into the charge transport layer (5).

FIG. 3 shows an additional surface protective layer (
7), and the photosensitive layer (4) is provided with a charge generation layer (
6) and a charge transport layer (5), it may be of a functionally separated type.

Fig. 4 shows a functionally separated photoreceptor having a charge generation layer (6) and a charge transport layer (5) similar to Fig. 2, but contrary to Fig. 2, the charge transport layer (5) is A charge generation layer is formed on the surface.

FIG. 5 shows an intermediate layer (8) between the substrate (1) and the photosensitive layer (4).
), and the intermediate layer (8) improves adhesion,
It can be provided to improve coating properties, protect the substrate, and improve charge injection from the substrate to the photosensitive layer. As the intermediate layer, polyimide resin, polyester resin, polyvinyltyral resin, casein, etc. may be used. The photoreceptor of this embodiment may also have a photosensitive layer of a functionally separated type.

The photoreceptor of the present invention can be prepared by dissolving or dispersing a distyryl compound represented by the general formula CI) together with a binder in a suitable solvent, and optionally adding a photoconductive material, an electron-withdrawing compound, a sensitizing dye, or other pigments. The coating solution obtained by adding
It can be manufactured by forming a photosensitive layer with a thickness of m, preferably 6 to 20 m.

Specifically, a charge generation layer and a charge transport layer i are formed on a conductive support.
The function-separated photoreceptor, which has a laminated structure similar to that of the photoreceptor shown in FIG.
A coating solution prepared by dispersing a binder resin in a solution is applied and dried to form a charge generation layer, and then a solution prepared by dissolving a distyryl compound and a binder in an appropriate solvent is applied and dried. It is obtained by forming a charge transport layer. At this time, the thickness of the charge generation layer is 4 μm or less, preferably 2 μm or less, and the thickness of the charge transport layer is 3 to 30 μm.
m1 is preferably 5 to 20 μm.

The proportion of the distyryl compound in the charge transport layer is 0.02 to 2 parts by weight, preferably 0.02 to 2 parts by weight, per 1 part by weight of the binder resin.
The amount is preferably 0.03 to 1.3 parts by weight. Further, other charge transport materials may be used in combination. In the case of polymeric charge transport materials that can themselves be used as binders, no other binder may be used. The structure of the photoreceptor may be similar to the photoreceptor shown in FIG. 4 described above, in which a charge transport layer is formed on a conductive support, and a charge generation layer is laminated thereon.

A photosensitive layer is formed on the conductive support, and the first layer described above is formed.
A dispersion type photoreceptor, which has a similar structure to the photoreceptor shown in the figure, is made by dispersing fine particles of a photoconductive material in a solution containing a distyryl compound and a binder resin, coating this on a conductive support, and drying it. Obtained by forming a photosensitive layer. The thickness of the photosensitive layer at this time is 3 to 30 μm, preferably 5 to 20 μm.
Good. If the amount of photoconductive material used is too small, the sensitivity will be poor, and if it is too large, the charging property will be poor and the strength of the photosensitive layer will be weakened.
The proportion of the distyryl compound is preferably 0.01 to 2 parts by weight, preferably 0.05 to 1 part by weight, per one part of resin, and the proportion of the distyryl compound is 0.01 to 2 parts by weight, preferably 0.02 to 1.2 parts by weight is suitable. It may also be used in combination with a polymeric photoconductor such as polyvinylcarbazole, which itself can be used as a binder. It may also be combined with other charge transport materials, such as hydrazone compounds.

The photoconductive materials used in the photoreceptor of the present invention include bisazo pigments, triarylmethane dyes, thiazine dyes, oxazine dyes, xanthine dyes, cyanine dyes, styryl dyes, pyrylium dyes, Azo pigments, chiacridone pigments, indigo pigments, perylene pigments, polycyclic bovine non-based pigments, bisbenzimidazole pigments, induthrone pigments, squarylium pigments,
Organic substances such as phthalocyanine pigments, selenium,
Examples include inorganic substances such as tellurium, selenium/arsenic, cadmium sulfide, and amorphous silicon.

Any other material can be used as long as it absorbs light and generates charge carriers with extremely high efficiency.

As the binder in the present invention, all electrically insulating thermoplastic resins, thermosetting resins, photocurable resins, and photoconductive resins that are known per se can be used.

Examples of suitable binder resins include, but are not limited to, saturated polyester resins, polyamide resins,
Acrylic resin, ethylene-vinyl acetate copolymer, ionically crosslinked olefin copolymer (y-ionomer), nutylene-butadiene block copolymer, polyarylate, polycarbonate, vinyl chloride-vinyl acetate copolymer, cellulose ester, polyimide, Thermoplastic binders such as styrene resins; thermosetting binders such as epoxy resins, urethane resins, silicone resins, phenolic resins, melamine resins, xylene resins, alkyd resins, thermosetting acrylic resins; photocurable resins; These include photoconductive resins such as IJ-N-vinylcarbazole, polyvinylpyrene, and polyvinylanthracene. These can be used alone or in combination.

These electrically insulating resins are measured individually to 1 x 1012Ω.
・It is desirable to have a volume resistivity of 100 or more.

More preferred are polyester resin, polycarbonate, and acrylic resin.

In addition to the binder, the photoreceptor of the present invention contains a plasticizer such as halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, dibutyl phthalate, and 0-terphenyl.
Electron-withdrawing sensitizers such as chloranil, tetracyanoethylene, 2,47-dolinitro-9-fluorenone, 56-dicyazbenzoquinone, tetracyanoquinodimethane, tetrachlorophthalic anhydride, 45-dinitrobenzoic acid, methyl violet, rhodamine B, cyanine dyes, pyrylium salts, thiapyrylium salts, and other sensitizers may be used.

The photoreceptor formed in this manner may have an adhesive layer, an intermediate layer, and a surface protection layer as required, as shown in FIGS. 3 and 5 described above.

As described above, the distyryl compound of the present invention can be combined with various photoconductive materials and binder resins,
Further, the photoreceptor using the distyryl compound of the present invention can be used as either a functionally separated type or a dispersed type, and is extremely easy to manufacture and has a wide range of uses.

Effects of the Invention The distyryl compound of the present invention has excellent properties as a charge transport material, and the photoreceptor obtained using the styryl compound has high sensitivity and low residual potential, and has excellent electrophotographic properties even after repeated use. It is stable and has excellent durability.

Synthesis Example 1 (Synthesis of distyryl compound (1)) Diethyl benzylphosphonate 2°287. I-Lihue 1.2-
Add this to 20 ml of dimethoxyethane, f, 50%
0.50y of sodium hydride was added, and the mixture was stirred at room temperature for 3 hours to react. Thereafter, the mixture was heated under reflux for about 30 minutes. After cooling to room temperature, the reaction mixture was poured into 200 ml of water.
The generated precipitate was collected by filtration, washed with water, and dried to give 1.46&(
A powder with a yield of 65% was obtained. Further, this powder was recrystallized from ethyl acetate and methanol to obtain a pale yellow distyryl compound.

The melting point of the obtained distyryl compound was 134-137°C.

1 part by weight, polyester resin (Byron 200 Toyobo)
1 part by weight) and 50 parts by weight of tetrahydrofuran were placed in a ball mill pot and dispersed for 24 hours to obtain a photosensitive coating liquid. This was coated onto an aluminum substrate so that the film thickness after drying was 1 μm, and dried to form a charge generation layer.

The above-mentioned distyryl compound (1) is placed on this charge generation layer.
10 parts by weight, polycarbonate resin (Panrye l-K
-1300 (manufactured by Teijin Kasei ■) dissolved in 80 parts by weight of tetrahydrofuran, a coating solution was applied so that the film thickness after drying was 20μ, and dried to form a charge transport layer to prepare photoreceptor A. did.

The thus prepared photoreceptor A was installed in a commercially available electrophotographic copying machine (EP450Z manufactured by Minolta Camera ■), and corona discharge was performed at 15 KV. :(E7 Example 5 50 parts by weight of copper phthalocyanine and 0.2 parts by weight of copper tetranitro phthalocyanine were dissolved in 500 parts by weight of 98% concentrated sulfuric acid with thorough stirring, and this was poured into 5000 parts by weight of water to dissolve copper phthalocyanine and copper tetranitro. After the phthalocyanine photoconductive material composition was precipitated, it was filtered, washed with water, and dried at 120° C. under reduced pressure.

10 parts by weight of the resulting photoconductive material composition was mixed with 2 parts of thermosetting acrylic resin (Acridic A405 Dainippon Ink ■).
2-5 parts by weight, melamine resin (Super Beckamine J8
7.5 parts by weight of the above-mentioned distyryl compound (11110 parts by weight) (manufactured by Dainippon Ink 20) and 100 parts by weight of a mixed solvent containing equal amounts of methyl ethyl ketone and xylene were placed in a ball mill pot and dispersed for 48 hours to obtain photoconductive properties. A coating material was prepared, and this coating liquid was applied onto an aluminum substrate so that the film thickness after drying was about 15 μm, and dried to form a photoconductive layer to prepare a photoreceptor H.

The thus prepared photoconductor () was processed in the same manner as in Example 1, except that corona discharge was performed at +6xv and vO1El/
2. Measure DDRs and VR.

Example 6 Photoreceptors I and J were prepared in the same manner as in Example 5, except that the distyryl compound (1
Photoreceptors containing distyryl compounds (121, +13) in place of 1) were prepared.

Vo, El/2, DDRs, and VR were measured for photoreceptors I and J thus prepared in the same manner as in Example 5.

Photoreceptors I (Vo of ~J) obtained in Examples 1 to 6.

Es/2. The measurement results of DDRs and VR are shown in Table 1.

As shown in Table 1, the photoreceptor containing the distyryl compound of the present invention has good charging ability, high sensitivity, and low residual potential and dark decay rate, regardless of whether it is a single layer type or a laminated type, and has excellent electrophotographic characteristics. It turns out that it is excellent.

[Brief explanation of drawings]

FIGS. 1 to 5 are diagrams of photoconductors according to the present invention, in which FIGS. 1, 3, and 5 are formed by laminating a photoconductor layer on a conductive support. The structure of a dispersed photoreceptor is shown, and FIGS. 2 and 4 show the structure of a functionally separated photoreceptor in which a charge generation layer and a charge transport layer are laminated on a conductive support.

Claims (1)

[Claims] 1. General formulas: ▲ Numerical formulas, chemical formulas, tables, etc. The group may have a substituent. However, unless R_1 and R_2 become hydrogen at the same time, R_1 and R_2 may be combined to form a ring. R_3 represents an alkyl group, an aralkyl group, an alkoxy group, or an aryl group, and each group may have a substituent. Further, R_3 may be a group represented by the following formula [II]. Formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [II] [In the formula, R_1, R_2, R_4 have the same meaning as [I]] R_4 represents hydrogen, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, and each The group may have a substituent. ] A distyl compound represented by 2. A photoreceptor containing a distyryl compound represented by the following general formula [I] as a charge transport material. General formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] [In the formula, R_1 and R_2 represent hydrogen, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group, and each group has a substituent It's okay. However, unless R_1 and R_2 become hydrogen at the same time, R_1 and R_2 may be combined to form a ring. R_3 represents an alkyl group, an aralkyl group, an alkoxy group, or an aryl group, and each group may have a substituent. Further, R_3 may be a group represented by the following formula [II]. Formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [II] [In the formula, R_1, R_2, R_4 have the same meaning as [I]] R_4 represents hydrogen, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, and each The group may have a substituent. ]