JPH02180884A - Novel compound and pigment and electrophotographic sensitive substance using the same - Google Patents

Abstract

NEW MATERIAL:A compound expressed by formula I [R1 to R6 are H, halogen, nitro, cyano, acyl, carbonyl, (substituted) alkyl or aryl; X is S or O; a, b, d and e are 0-4; c and f are 0-2]. EXAMPLE:A compound expressed by formula II. USE:A pigment and charge generating substance for electrophotographic sensitive substances. PREPARATION:A compound expressed by formula III is reacted with a sulfurating agent (preferably tetraphosphorus trisulfide, tetraphosphorus heptasulfide, tetraphosphorus decasulfide, pyridine complex thereof and dithiophosphetane) in an inert solvent, such as benzene, in nitrogen atmosphere at 50-250 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a novel compound and a pigment using the same. Furthermore, the present invention relates to an electrophotographic photoreceptor using the compound of the present invention as a charge generating substance.

(Prior Art) The electrophotographic method has already been published by Carlson in US Patent No. 2.297.
As disclosed in No. 691, it is a clever combination of electrostatic phenomenon and photoconductive phenomenon, and after uniformly charging one surface of a photoconductive photoreceptor by corona discharge etc. in a dark place, It is an image forming method that uses photoconductivity to convert an optical image into an electrostatic latent image, and then attaches colored charged powder (toner) to this image to convert it into a visible image.

The basic electrical properties required of a photoreceptor in such electrophotography are that it can be charged to an appropriate potential in a dark place, that this potential can be maintained for an appropriate amount of time, and that the charge can be quickly dissipated by light irradiation. Examples include things that can be dispersed.

Conventionally, inorganic photoconductive materials such as amorphous selenium, cadmium sulfide, and zinc oxide have been widely used in photoreceptors for general copying machines. Although these inorganic materials satisfy the above conditions, For example, cadmium sulfide and zinc oxide are dispersed in a resin as a binder and used as a photoreceptor, but they have poor smoothness, flexibility, hardness, and tensile strength.

Since it has mechanical defects such as abrasion resistance, it cannot withstand repeated use as it is. Furthermore, when using cadmium sulfide, consideration must also be given to hygiene issues.

In addition, amorphous selenium is not only expensive to manufacture, it is not flexible and difficult to process into a belt shape, and it is difficult to handle because it is toxic and sensitive to heat and mechanical shock. has drawbacks such as the need for caution.

In recent years, in order to eliminate the drawbacks of these inorganic photoreceptors,
Research on organic photoreceptors is progressing, and organic photoreceptors.

Two types of organic photoreceptors have been proposed and put into practical use because they have many advantages such as ease of film formation, ease of manufacture, light weight, flexibility, and variable spectral sensitivity.

For example, a photoreceptor made of poly-N-vinylcarbazole and 2,47-dolinitrofluorene (U.S. Patent No. 3.
484.237), poly-N-vinylcarbazole sensitized with pyrylium salt dye (Japanese Patent Publication No. 4B-25
658), and a photoreceptor whose main component is a eutectic complex consisting of a dye and a resin (Japanese Unexamined Patent Publication No. 10735/1983).

Furthermore, an electrophotographic photoreceptor has been proposed that combines a substance that generates electric charges when exposed to light and a substance that moves the generated electric charges.For example, US Pat. A photoreceptor having a charge transport layer thereon is also described, and U.S. Pat. No. 3,764,315 describes a photoreceptor having a photosensitive layer having a charge generating material dispersed in the charge transport material. That is, the combination of a charge-generating substance and a charge-transferring substance provides better characteristics and provides a useful photoreceptor.

Up to now, many proposals have been made for using azo compounds, polycyclic quinone compounds, perylene compounds, etc. as charge generating substances in this type of photoreceptor.

However, these compounds do not necessarily fully satisfy the characteristics such as sensitivity, residual potential, or stability during repeated use, and the selection range of charge transfer materials is also limited, which makes them difficult to meet the wide demands of electrophotographic processes. The reality is that nothing that fully satisfies has yet been found.

In addition, we are also developing high-grade pigments with even better properties for use as R materials, i.e., color properties such as one hue, coloring power, transparency, etc.
Fastness such as light resistance, heat resistance, bleed resistance, migration resistance, and chemical resistance; dispersibility when used in printing inks, paints, plastics, III-based textile printing, etc. 1. Fluidity of the dispersion; High-grade pigments with excellent usability such as gloss of painted objects are also needed in many fields.

(Problems to be Solved by the Invention) The present invention relates to a novel compound, and furthermore, it is an electronic compound containing a specific compound that is not only used for pigments but also has excellent sensitivity, repeatability, durability, etc. The present invention provides a photographic photoreceptor.

[Structure of the invention]

(Means for Solving the Problem) As a result of intensive research, the present inventors invented a compound having a specific structure, and further discovered that it is a charge-generating substance useful for electrophotographic photoreceptors. The present invention was completed by discovering that an electrophotographic photoreceptor using this charge generating substance has excellent properties.

That is, (1) the present invention provides an electrophotographic photoreceptor containing this specific compound, which is an excellent compound as a high-grade pigment, and furthermore has excellent sensitivity, repeatability, durability, etc.0 (Objective of the present invention) The object of the present invention is to provide a high-grade pigment that has excellent pigment use, namely, chromatic properties, fastness, dispersibility, fluidity, and gloss.

Another object of the present invention is to provide an electrophotographic photoreceptor with high sensitivity, low residual potential, high charge generation efficiency, and high copying speed, using the compound discovered by the present invention as a charge generation substance. A further object of the present invention is to reduce fatigue deterioration due to repeated use when used as a photoreceptor for electrophotography in which charging exposure, development, and transfer steps are repeated, and furthermore, it is preferable to use the photoconductor under high temperature rather than low temperature and high humidity than low temperature. under various harsh environments.

An object of the present invention is to provide an electrophotographic photoreceptor that maintains stable characteristics and has excellent durability and environmental resistance.

This object of the present invention is achieved by at least one compound represented by the following general formula [I].

(R3)c (wherein R9-R6 represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, an acyl group, a carbonyl group, an alkyl group which may have a substituent, or an aryl group).

X represents a sulfur atom or an oxygen atom, a, b, d.

e represents an integer of 0 to 4, and c and f represent integers of 0 to 2. ) Furthermore, in the electrophotographic photoreceptor having a photosensitive layer on a conductive support, the charge generating substance is at least one compound represented by the general formula [I] according to claim 1. This is a characteristic electrophotographic photoreceptor.

Furthermore, in an electrophotographic photoreceptor comprising a charge generation layer and a charge transfer layer laminated on a conductive support.

It is an electrophotographic photoreceptor in which the charge generating substance is at least one compound represented by the above general formula [I], and the charge generating layer is formed by vapor deposition or dispersion with a binder polymer. In addition, there are charge transfer substances.

This can be achieved by using an electrophotographic photoreceptor which is a 1-dracine compound or a styryl compound and, if necessary, has an organic or inorganic barrier layer on a conductive support. These general formulas (1) may be used alone, or if necessary, two or more compounds within the range of general formula (1) may be used in combination. Cargo transport substances may also be used alone.

If necessary, two or more types may be used in combination.

The compound represented by the general formula [I] of the present invention is produced by heating the compound represented by the following general formula (II) together with a sulfurizing agent.

(R3)c The sulfurizing agent to be used may be any reagent as long as it has a sulfurizing effect, but preferably tetraphosphorus trisulfide, tetraphosphorus heptasulfide,
Tetraphosphorus decasulfide and its pyridine complex.

Dithiophosphetane, 2,4-bis-(4-methoxyphenyl)-1,3-dithia-2,4-diphosphethane-2,4-disulfide are preferred, and the sulfurization reaction is carried out at a temperature of 50 to 250°C in an inert solvent. It is preferable to carry out the reaction in a nitrogen atmosphere.

The inert solvents used are aromatic hydrocarbons such as benzene, toluene, and xylene, and ethers such as dioxane, tetrahydrofuran, and dimethoxy ether.

Nitriles of the acetonitrile class, chlorobenzene.

Chlorinated hydrocarbons such as dichloromethane and chloroform,
There are amides and thioamides such as dimethylformamide and tetraethylsulfamide.

It is not limited to these.

Although the compound obtained by the above method is sufficient for use, it is also effective to add a recrystallization or sublimation purification treatment step to further improve the chemical purity.

The electrophotographic photoreceptor is also formed by using a charge generation substance and a charge transfer substance on a conductive support, in which the charge generation substance is a compound of general formula [11], and furthermore, the charge generation substance is a compound of general formula [11], There is a method in which the generation layer is prepared by vapor deposition of the charge generation substance or by coating a coating liquid in which the charge generation substance is dispersed together with a binder polymer, and a method in which a charge transfer layer is laminated, or a method in which the charge transfer layer is formed as a single layer.

These compounds may be used alone or in combination of two or more.

It is preferable to use these compounds after thorough washing with organic solvents such as ketones, alcohols, and nitrogen-containing organic solvents.By washing with organic solvents, charge-generating substances with high electrophotographic properties such as sensitivity can be used. can get.

The photoreceptor of the present invention contains a specific compound as a charge-generating substance as described above, and also contains various charge-transfer substances. You get a body.

For example, a charge transport material is provided on a conductive support substrate in the same layer as a charge generating material. A structure called a single-layer photoconductor, or a layer containing a charge-generating substance.

It can be used in a laminated photoreceptor in which a layer containing a charge transfer substance is laminated on a conductive support substrate. These structures differ depending on the polarity of the photoreceptor used; in the case of a positively charged photoreceptor, the photoreceptor is a single-layer type or consists of a support/charge transfer N/charge generation layer, and in the case of a negatively charged photoreceptor, a support/charge generation layer is used.
A photoreceptor having a charge generation layer/charge transfer layer in this order is used, but the method is not limited thereto.The charge generation layer can also be produced by vapor deposition of the charge generation substance. The compound of the present invention is sufficiently practical as a charge-generating substance, but in order to further improve the photosensitivity, it is necessary to add a solvent to the charge-generating layer after forming the charge-generating layer. There is a method of exposing it to steam. By exposing a charge generating layer using the compound of the present invention to solvent vapor, the dark resistance and photoconductivity increase, and accordingly, the photosensitivity also increases. In addition, the absorption wavelength may also become longer at the same time, and a shift of 1100n or more was observed depending on the solvent. The solvent used may be any solvent, but preferably benzene and toluene.

Xylene, dioxane, tetrahydrofuran, dimethoxy ether, acetonitrile, chlorobenzene.

These include dichloromethane, chloroform, dimethylformamide, dimethylsulfoxide, tetraethylsulfamide, acetic acid ethyl ester, methanol, and ethanol. Dark resistance, increase in photoconductivity, and shift to longer wavelengths can be achieved not only by treating the charge generation layer with solvent vapor, but also by cleaning the charge generation material itself with the above solvent, and by making the particles of the charge generation material finer. A similar effect can be obtained by the following method.

Charge transfer substances used in the present invention include hydrazones, pyrazolines, and diarylalkanes.

Alkylene diamines, triphenylamines, benzylanilines, diphenylbenzylamines.

Examples include various compounds such as triarylalkanes, oxadiazoles, oxazoles, stilbenes, and anthracenes, but are not limited to these.

Further, the charge transfer substance is more preferably a hydrazone compound or a styryl compound.

The binder (binder polymer) preferably used in the charge generation layer and charge transfer layer in the present invention is as follows.

It is a highly electrically insulating film-forming polymer or copolymer. Such high molecular weight polymers.

9 The binders preferably used in the present invention are phenolic resins, polyester resins, vinyl acetate resins, polycarbonate resins, polypeptide resins, cellulose resins, polyurethane resins, polyvinylpyrrolidone, polyethylene oxide, and polyvinyl chloride resins. , starch, polyvinyl alcohol, acrylic copolymer resin, vinyl chloride vinyl acetate copolymer resin, methacrylic copolymer resin silicone resin, polyacrylonitrile copolymer resin, polyacrylamide, polyvinyl butyral,
Examples include polyvinylcarbazole, polyvinylidene chloride resin, and silicone resin.

These binder polymers can be used alone or in a mixture of two or more, but the binders that can be used in the present invention are:
It is not limited to these. Further, in the photoreceptor of the present invention, a charge generation layer mainly composed of a charge-generating substance is provided on the conductive support via an intermediate layer if necessary, and a charge-generating layer mainly composed of a charge-transfer substance is provided adjacent to the core layer. A stacked structure including a charge transfer layer may also be used. In addition, when such a laminated structure is adopted, which of the charge generation layer and the charge transfer layer is to be used as the upper layer is determined depending on whether the chargeability is positive or negative. Generally, when negatively charged, it is advantageous in terms of characteristics to have a charge transfer layer as an upper layer. In addition, when the photoreceptor of the present invention has a laminated structure consisting of separate layers of a charge generation layer and a charge transfer layer, the photosensitive layer is placed directly on the conductive support or, if necessary, with an intermediate layer such as a barrier layer. A method of applying a dispersion obtained by micronizing a charge-generating substance in a dispersion solvent using a ball mill, attritor, etc. and mixing and dispersing an appropriate solvent and a binder as necessary on a layer, or vapor deposition. After the charge generation layer is prepared by the method, a solution of a charge transfer substance and a binder dissolved in an organic solvent such as dioxane, dichloromethane, dichloroethane, or tetrahydrofuran is further prepared.

In addition, in the case of a single-layer type photoreceptor, a charge generating substance, a charge transfer substance, and a binder are added to the same organic solvent, and a coating liquid is dispersed using a ball mill, an attritor, etc., and then applied to a conductive support. .

Further, the charge transfer substance used in the present invention is binder 10
Preferably, 10 to 300 parts by weight of the charge transfer material per 0 parts by weight are used, although the present invention is not limited to this range. Also, what is the thickness of the photosensitive layer?

Required photosensitivity, durability, 1M, and charge-generating substances.

The thickness of the photosensitive layer on the supporting conductive substrate is preferably 50 microns or less, depending on the mixing ratio of the charge transfer substance to the binder, whether it is a single layer type or a multilayer type.
~30 microns is appropriate from the viewpoint of film flexibility. Further, in order to improve the durability and environmental resistance of the photoreceptor, it may contain a number of additives 9, such as ultraviolet absorbers, antioxidants, surfactants, and the like.

The photosensitive layer can also be coated with a layer that serves as a protective layer, if necessary.

The support used in the electrophotographic photoreceptor of the present invention includes:

Any material may be used as long as it is imparted with electrical conductivity, and any type of electrically conductive layer conventionally used may be used. Specifically, aluminum and copper.

Stainless steel 7, metals such as brass, aluminum, plastics or conductive particles on which indium oxide, tin oxide, etc. are vapor-deposited or laminated 2 For example, carbon blanks,
Examples include plastics in which tin particles and aluminum particles are dispersed. Further, the shape thereof may be a sheet shape, a cylinder shape, or other shapes.

The compounds of the present invention can be used in a wide range of fields and are suitable as highly functional organic dye materials such as coloring materials, charge generating materials for electrophotographic photoreceptors, and absorbing materials for optical recording. .

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to the following examples. Hereinafter, "parts" indicate parts by weight.

Example 1 In a flask equipped with a stirrer, a thermometer, and a reflux condenser, 31.2 parts of the following quinacridone compound [■-a] and 2.
4-bis(4-methoxyphenyl)-1゜3-dithia-
48.5 parts of 2,4-diphosphethane 2,4-disulfide (Laga Esson reagent), 30 parts of hexamethylphosphoric acid triamide, and 600 parts of xylene were added.

After cooling to 90°C and filtering, the mixture was filtered with xylene, acetone, and methanol in that order, and dried to obtain 22.6 parts.

The analytical values of the compound obtained in this example are shown below.

Elemental analysis values: Theoretical values: C-69.8% N-8.1%H
3,5% S = 18,6% C - 69,5%
N-8.0% H-3.4% S-19.1% Mass spectrometry value
C/Z-344 Based on the above results, the experimental value of the compound obtained in this example was the compound represented by (1-a).

The IR (infrared rays) absorption spectrum of the compound obtained in this example is shown in FIG. Moreover, IR absorption spectrum of (na) is shown in FIG. 1.

Examples 2-11 A quinacridone compound is added to a flask equipped with a stirrer, a thermometer, and a reflux condenser under the conditions shown in Table 1. Furthermore, 2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane 2°4-disulfide (
48.5 parts of Lawesson's reagent), 35 parts of hexamethylphosphoric acid triamide, and 700 parts of xylene are added, and the mixture is heated at 135° C. for 6 hours in a nitrogen atmosphere.

After cooling to 90°C and filtering, the mixture was filtered with xylene, acetone, and methanol in this order, and dried.

Table 2 shows the analytical values of the compounds obtained in this example.

The method for producing the photoreceptor shown in Table 1 is as follows: 3 parts of the compound produced in Examples 1 to 11, 3 parts of vinyl chloride-vinyl acetate copolymer resin (1000E, manufactured by Kagaku Co., Ltd.), and 94 parts of tetrahydrofuran, were milled in a ball mill. The mixture was dispersed for 4 hours.

This coating solution was applied onto a PET film on which aluminum was vapor-deposited to obtain a charge generation layer of 0.4 μm. As a zero-order charge transfer agent, 10 parts of the following hydrazone compound and a polycarbonate resin (Panlite manufactured by Kijin Kasei Co., Ltd.) were used as a charge transfer agent. 1300) 10
A coating solution prepared by dissolving 50 parts of the sample in 80 parts of methylene chloride was applied onto the charge generation layer and dried to prepare a charge transfer layer of 18 μm.

The photoreceptor obtained by the above method was subjected to corona discharge at -5.9 kV with a corona gap of 10 mm and a charging speed of 11 parts mm/sec, and after 2 seconds after the discharge was stopped, it was exposed to a 2854 tungsten light source for 5.5 seconds. Expose at an illuminance of OL u x. The amount of light irradiation required for the potential immediately before exposure to decrease by 50% at this time was measured as sensitivity (El/2). The results are shown in Table 4.

It can be seen from the results that the photoreceptor of the present invention has good electrophotographic properties.

Examples 12-14 Table 5 shows the charge generating substances used in this example.

Table 5 A photoreceptor was prepared in the same manner as in Examples 1 to 23, except that the compound shown in Table 5 was vapor-deposited under a pressure of 1 Torr to form a charge generation layer of 0.3 μm. The electrophotographic properties were measured.The results are shown in Table 6.

Table 6 It had photographic properties, and in particular had good charging properties.

Examples 15-17 Single-layer photosensitization using the compounds listed in Table 7 as charge-generating substances.

A body was prepared and the electrophotographic properties were measured.

1 part of the compound shown in Table 7, 1 part of hydrazone compound and 6 parts of polyester resin (Toyobo Byron 200) were added to THF.
The coating solution was dispersed in a ball mill for 3 hours with 20 parts of the coating solution, and then applied onto a PET film on which aluminum was vapor-deposited, and dried to produce a 17 μm single-layer photoreceptor. The electrophotographic properties were measured in the same manner as in Example 1-11, except that a positive corona charge (+5.0 kV) was applied. The results are shown in Table 7.

From the above results, it can be seen that the photoreceptor of Example 1 has good electrophotographic properties.The photoreceptor of Example 2 has good electrophotographic characteristics.

Comparative Example 1 Photoreceptors were prepared in the same manner as in Examples 1 to 11, except that the following perylene compound was used as a charge generating agent, and their electrophotographic properties were measured. The results are shown in Table 8.
From the results shown in the table above, it was found that the photoreceptors of the two comparative examples had inferior sensitivity and high residual potential compared to the examples.

From the above results, it was confirmed that the photoreceptors obtained according to the present invention had good electrophotographic properties.

Furthermore, the compound obtained according to the present invention was a pigment excellent in use as a pigment, ie, dichromatic properties, fastness, monodispersity, fluidity, and gloss.

〔Effect of the invention〕

According to the present invention, a novel compound excellent in use as a pigment was obtained. A photoreceptor for electrophotography was prepared using the compound of the present invention, and excellent properties were obtained. Furthermore, the compound of the present invention can be used in recording materials and other applications, making it an extremely effective invention.

[Brief explanation of the drawing]

1 to 4 show Example 1 (1-a), respectively. IR absorption spectra of (II-a), Example 4 (1-d), and (ff-d) are shown.

Claims (1)

[Claims] 1. A compound represented by the following general formula [I]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] (In the formula, R_1 to R_6 are hydrogen atoms, halogen atoms, nitro groups, cyano groups, acyl groups, carbonyl groups, alkyl groups that may have substituents, represents an aryl group, x represents a sulfur atom or an oxygen atom, and a, b, d, e are 0 to 4
The integers c and f represent integers from 0 to 2. ) 2. A pigment using a compound represented by the above general formula [I]. 3. In an electrophotographic photoreceptor comprising a photosensitive layer on a conductive support, the charge generating substance has the general formula according to claim 1 [
An electrophotographic photoreceptor comprising at least one compound represented by [I]. 4. In an electrophotographic photoreceptor comprising a charge generation layer and an electron transfer layer laminated on a conductive support, the charge generation substance is the compound according to claim 1, and the charge generation layer is formed by vapor-depositing the charge generation substance. An electrophotographic photoreceptor characterized by: 5. An electrophotographic photoreceptor comprising a charge generation layer and an electron transfer layer laminated on a conductive support, wherein the charge generation substance is the compound according to claim 1, and the charge generation layer is a combination of the charge generation substance and a binder polymer. An electrophotographic photoreceptor characterized by being formed by. 6. The electrophotographic photoreceptor according to any one of claims 2 to 4, wherein the charge transfer substance is a hydrazone compound or a styryl compound. 7. The electrophotographic photoreceptor according to any one of claims 2 to 5, which has an organic or inorganic barrier layer on the conductive support.