JPS63172274A - Photoconductive film and electrophotographic sensitive body using said film - Google Patents

Abstract

PURPOSE:To obtain a photoconductive film having photoconductivity of high sensitivity and an electrophotographic sensitive body using said film by using a specific photoconductive org. compd. CONSTITUTION:The photoconductive film contains at least one kind of the tetraazafluvalence compd. expressed by the formula. In the formula, (n) denotes 0 or positive integer, R1-R8 denote a hydrogen atom, halogen atom, monovalent org. residue or residue in which the adjacent two groups form a condensation ring with the tetraazafluvalene compd. The electrophotographic sensitive body is provided with a photosensitive layer having the photoconductive film contg. at least one kind of the tetraazafluvalence compd. expressed by the formula on a conductive base. Said compd. is used as a photoconductive compd. for electrophotography, more particularly as a carrier generating material, by which the electrophotographic sensitive body having the excellent sensitivity is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a photoconductive coating containing a novel organic photoconductive compound and an electrophotographic photoreceptor using the same.

"Prior Art and its Problems" As electrophotographic photoreceptors, those having a photosensitive layer containing as a main component an inorganic photoconductive compound such as selenium, zinc oxide, or cadmium sulfide have been widely known. However, these materials are not satisfactory in terms of properties such as thermal stability and durability, and also have problems in production and handling due to their toxicity.

On the other hand, electrophotographic photoreceptors having a photosensitive layer containing an organic photoconductive compound as a main component are relatively easy to manufacture, inexpensive, and easy to handle. It has attracted attention in recent years because it has many advantages such as superior thermal stability. Poly-N-vinylcarbazole is the most well-known such organic photoconductive compound;
．． Electrophotographic photoreceptors having a photosensitive layer containing as a main component a charge transfer complex formed from a Lewis acid such as 7-dolinitro and 9-fluorenone have already been put to practical use.

Further, electrophotographic photoreceptors are known that have a functionally separated photosensitive layer of a laminated type or a dispersion type in which the carrier generation function and the carrier transport function of the photoconductor are assigned to separate substances, respectively. For example, an electrophotographic photoreceptor having a photosensitive layer consisting of a carrier generation layer made of an amorphous selenium thin film and a carrier transport layer containing poly-N-vinylcarbazole as a main component has already been put into practical use.

Furthermore, in an electrophotographic photoreceptor having the above-mentioned functionally separated photosensitive layer, attempts have been made to use organic photoconductive compounds as both the carrier generating substance and the carrier transporting substance. , azo dyes, phthalocyanine dyes, anthraquinone dyes, perylene dyes, cyanine dyes, thiapyrylium dyes, squareium dyes, etc. Also, as carrier transport substances, amine derivatives, oxazole derivatives, oxadiazole derivatives, triphenyl Methane derivatives are known.

These carrier-generating substances and carrier-transporting substances are
When it does not have the ability to form a film by itself, it is used in combination with various binders to form a film. Then, on a conductive support (an electrophotographic photoreceptor formed by laminating a layer having a carrier-generating substance and a layer having a carrier-transporting substance), or containing a carrier-generating substance and a carrier-transporting substance in a dispersed state, An electrophotographic photoreceptor is known that has a layer formed thereon.

However, electrophotographic photoreceptors using organic photoconductive compounds as carrier generating substances still have lower photoconductive sensitivity and durability than those using inorganic photoconductive compounds. Because it is inferior in terms of

"Object of the Invention" An object of the present invention is to provide a highly sensitive photoconductive coating and an electrophotographic photoreceptor using the same by employing a novel organic photoconductive compound.

"Structure of the Invention" The photoconductive film according to the present invention is characterized by containing at least one type of tetraazafulvalene compound represented by the following general formula (1).

(In the formula, n represents 0 or a positive integer, and 81 to R8 are hydrogen atoms, halogen atoms, monovalent organic residues, or two groups in contact with Fa form a condensed ring with the tetraazafulvalene compound. Furthermore, the electrophotographic photoreceptor according to the present invention comprises a photoconductive coating containing at least one type of tetraazafulvalene compound represented by the general formula (1) on the conductive support. The invention is characterized in that it is provided with a photosensitive layer having the following properties.

Until now, there has been no attempt to use the tetraazafulvalene compound represented by the general formula (1) as a photoconductive compound for electrophotography. (This is a carrier.

The present inventors discovered that an electrophotographic photoreceptor having excellent sensitivity can be obtained by using it as a generating substance, and have completed the present invention.

In the general formula (1), n represents 0 or a terminating integer, and R7-R8 are a hydrogen atom, a halogen atom, a monovalent organic residue, or two groups in contact with each other are condensed with a tetraazafulvalene compound. It represents a ring-forming residue, and examples of -valent organic residues include alkyl groups, alkoxy groups, substituted or unsubstituted aryl groups, substituted or unsubstituted aralkyl groups, acyl groups, and substituted or unsubstituted aryl groups. When the carbon skeleton of an unsubstituted amine group, a substituted or unsubstituted styryl group, a nitro group, a hydroxy group, a carboxyl group, an ester group, a cyano group, a substituted or unsubstituted arylazo group, or any of these organic residues is replaced with a nitrogen atom, oxygen atom,
Examples include groups substituted with a hetero atom such as a sulfur atom.

Specific examples of the compound represented by the general formula (1) include the following.

The compound represented by the general formula (1) can be synthesized according to the reaction formula shown in FIG. 7 or 8. In addition, in the figure, the symbols in the formula have the same meanings as the symbols in the general formula (1). Details of this synthesis method can be found in Tetrahe
Dron Letters, No. 42.5221-
5223 (1966), J.Chem.Soc., 1B.
87.552, Anc+ew.

Chem,; 7B, 303 (1966), J. Pr.
akt, Chem, 23,225-233 (+96/
I) etc.

For example, a synthesis example of the compound represented by the structural formula (15) is as follows.

89% of terephthaldehyde, 25.29% of benzyl, and 64.2% of ammonium acetate in 1600ml of vinegar
9 @Dissolved, heated under reflux for 2 hours, and after eluting the solvent, crude 1°4-bis(4,5-diphenylimidazole-2-
Fig. 2 shows an example in which a lyse transport layer 3 is provided, and 27.89% of caribenzene is obtained. This is purified by recrystallization from pyridine to obtain 209 pure 1,4-bis(4,5-diphenylimidazol-2-yl)-benzene. Next, this was reacted with sodium hydride in dry pyridine to obtain 1nI5q@ of sodium 1,4-bis(4,5-diphenylimidazol-2-yl)-benzene. This was oxidized with bromine in methylene chloride, the solution was concentrated, and the precipitated compound was collected by filtration.
Compound 129 shown in 5) is obtained.

Note that other compounds can also be synthesized in the same manner as in the above synthesis example.

The electrophotographic photoreceptor of the present invention uses the organic photoconductive compound represented by the general formula (1) as a carrier generating substance, and can have, for example, the following structure.

As shown in FIG. 1 or 2, a laminate of a carrier generation layer 2 containing a carrier generation substance as a main component and a carrier transport layer 3 containing a carrier transport substance as a main component on a conductive support 1 is formed. A photosensitive layer 4 is provided. In FIG. 1, a dispersion obtained by dispersing carriers is coated on a carrier generation layer 2.

3 or 4 (As shown, a photosensitive layer 4 similar to the above is provided on a conductive support 1 with an intermediate layer 5 interposed therebetween.

As shown in FIG. 5 or 6, a fine particle carrier generating substance 7 is contained in a layer 6 mainly composed of a carrier transporting substance.
A photosensitive layer 4 formed by dispersing is directly on the conductive support 1,
Alternatively, it is provided via the intermediate layer 5.

The conductive support 1 may be a metal plate, or paper or plastic made conductive by coating, vapor depositing, or laminating a conductive compound such as a conductive polymer or indium oxide, or a metal thin film such as aluminum, palladium, or gold. is used.

The carrier-generating layer 2 is made by forming the carrier-generating substance represented by the general formula (1) into fine particles in a dispersion medium using a ball mill, a homomixer, a sand mill, a colloid mill, etc., and mixing it with a binder if necessary. It can be formed by applying the solution obtained by using a method such as a dipping method, a spray method, or a spinner method.

In this case, examples of the binder include phenol resin, polyester resin, vinyl acetate resin, polycarbonate resin, polypeptide resin, cellulose resin, polyvinyl and lolidone, polyethylene oxide, polyvinyl chloride resin, starch, polyvinyl alcohol, and acrylic resin. Copolymer resin, methacrylic copolymer resin, silicone resin,
Polyacrylonitrile copolymer resin, polyacrylamide, polyvinyl butyral, etc. can be used.

Note that the carrier generation layer 2 can also be formed by forming a compound represented by the general formula (1) into a thin film by a method such as vacuum deposition.

The carrier transport layer 3 can be formed by dispersing or dissolving a carrier transport substance in a binder similar to the above and applying the same. In the present invention, the carrier transport substance is not particularly limited, but for example, amine derivatives, oxazole derivatives, oxadiazole derivatives, triphenylmethane derivatives, etc. can be used.

The intermediate layer 5 disposed between the conductive support 1 and the photosensitive layer 4 has a barrier function and an adhesive function, and is made of, for example, casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer. , polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin, aluminum oxide, etc.

Further, the photosensitive layer 4 is formed by dispersing a fine particulate carrier generating substance 7 in a layer 6 mainly composed of a carrier transporting substance, by dispersing or dissolving the carrier transporting substance in the above-mentioned binder, Furthermore, it can be formed by applying a liquid in which a carrier generating substance is dispersed.

"Examples of the invention" Examples 1 to 5 2 parts by weight of butyral resin and 10 parts by weight of isopropyl alcohol
Five types of tetraazafulvalene compounds listed in the table below (the structural formula (3), (4)
), (+6), (17), (48) 5 parts by weight of the compounds) ground in a ball mill were added and dispersed to prepare five types of coating liquids. Then, apply 50% of each coating liquid.
The film thickness after drying is 0.3 u on a 0 um A1 plate.
It was coated using a doctor blade to give a charge generating layer of m and was dried to form a charge generation layer.

Next, 5 parts by weight of a hydrazone compound represented by the following structural formula and 5 parts by weight of polyvinylcarbazole were dissolved in 70 parts by weight of monochlorohenzene, and this was applied onto the charge generation layer so that the film thickness after drying was 20 um. The charge transport layer was coated using a 2° doctor blade and dried to form a charge transport layer.

Regarding the five types of electrophotographic photoreceptors obtained in this way,
Electrostatic charging test device (manufactured by Kawaguchi Electric ■, EPA-8100
Type) 18: Using the static method, corona charging to -6 with ■, followed by observing dark decay for 5 seconds,
The photoelectric characteristics were evaluated by observing the optical attenuation by exposure to x for 5 seconds. Initial charging potential (Vo) and sensitivity (Vo) measured in this way
El/2) and residual potential (VR) results are shown in the table below.

Table "Effects of the Invention" As explained above, according to the present invention, by using the novel organic photoconductive compound represented by the general formula (1), a photoconductive coating having a highly sensitive photoconductivity of 18 iV can be formed. And an electrophotographic photoreceptor can be obtained using the same. Therefore, the present invention can be widely applied to electrophotographic application fields in general, such as electrophotographic copying machines, laser beam printers, LED printers, and CRT printers.

[Brief explanation of the drawing]

1, 2, 3, 4, 5 and 6 are sectional views showing different specific examples of the layer structure of the electrophotographic photoreceptor according to the present invention, and FIGS. The figures are diagrams each showing a reaction formula for synthesizing the tetraazafulvalene compound used in the present invention. Fig. 1 Fig. 3 Fig. 5 Fig. 2 Fig. 4 Fig. 6 Temauri Neho Seisho (spontaneous) February 17, 1988 Patent Application No. 4699 2, Name of Invention Photoconductivity Sexual coating and electrophotographic photoreceptor 3 using the same, and its relationship to the amended case Patent applicant address 1-7 Yukitani Otsuka-cho, Ota-ku, Tokyo Name (
AO9) Alps Electric Co., Ltd. Representative Kataoka Kataoka 4, Agent 6, Contents of the amendment: that's all

Claims (2)

[Claims] (1) A photoconductive film characterized by containing at least one type of tetraazafulvalene compound represented by the following general formula (1). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) (In the formula, n represents 0 or a positive integer, and R_1 to R_8
represents a hydrogen atom, a halogen atom, a monovalent organic residue, or a residue in which two adjacent groups form a condensed ring with the tetraazafulvalene compound. ) (2) Electrophotographic sensitization characterized in that a photosensitive layer having a photoconductive film containing at least one type of tetraazafulvalene compound represented by the following general formula (1) is provided on a conductive support. body. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) (In the formula, n represents 0 or a positive integer, and R_1 to R_8
represents a hydrogen atom, a halogen atom, a monovalent organic residue, or a residue in which two adjacent groups form a condensed ring with the tetraazafulvalene compound. )