JPH0312661A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body having a practicable high sensitivity characteristic and the potential characteristics stable during repetitive use by incorporating a specific barbituric acid deriv. or thiobarbituric acid deriv. into a photosensitive layer. CONSTITUTION:The barbituric acid deriv. or thiobarbituric acid deriv. expressed by formula I is incorporated into the photosensitive layer on a conductive base. In the formula I, Y denotes an oxygen atom or sulfur atom; R1 denotes an arm. hydrocarbon group or arom. heterocyclic group which may be combined via a combination group and may have a substituent; R2, R3 denote a hydrogen atom, alkyl group or aryl group which may be substd. m denotes 1, 2 or 3 integer, n denotes 1, 2 integer. The electrophotographic sensitive body having the high sensitivity and the potential characteristics stable during repetitive use is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor in which the photosensitive layer contains a barbylic acid derivative or a thiobarbylic acid derivative having a specific structure. .

[Prior Art] Conventionally, inorganic photoconductive substances such as selenium, cadmium sulfide, and zinc oxide have been widely used as electrophotographic photoreceptors.

On the other hand, electrophotographic photoreceptors using organic photoconductive substances include photoconductive polymers typified by poly-N-vinylcarbazole and 2,5-bis(p-diethylaminophenyl)-1,3,4- Those using a low-molecular organic photoconductive substance such as oxadiazole, and those using a combination of such an organic photoconductive substance and various dyes and pigments are known.

Electrophotographic photoreceptors using organic photoconductive substances have good film forming properties, can be produced by coating, and have extremely high productivity.
It has the advantage of being able to provide an inexpensive photoreceptor. Furthermore, it has the advantage that color sensitivity can be freely controlled by selecting the sensitizer such as dye or pigment to be used, and a wide range of δζI tests have been carried out so far. In particular, recent developments have led to the development of functionally separated photoreceptors in which a charge generation layer containing an organic photoconductive dye or pigment is laminated with a charge transport layer containing the aforementioned photoconductive polymer or low-molecular organic conductive substance. Significant improvements have been made in the sensitivity and durability, which were considered to be shortcomings of conventional organic electrophotographic photoreceptors.

As these materials exhibiting photoconductivity, for example, Ara pigments and barbylic acid derivatives or thiobarbylic acid derivatives described in JP-A-57-119355 are known.

However, conventional electrophotographic photoreceptors using disazo pigments, barbylic acid derivatives, and thiobarbylic acid derivatives are not satisfactory in terms of sensitivity and potential stability during repeated use, and have not been put into practical use. Only a few materials are needed.

[Problems to be Solved by the Invention] An object of the present invention is to provide a novel photoconductive material;
The object of the present invention is to provide an electrophotographic photoreceptor having practical high sensitivity characteristics and stable potential characteristics during repeated use.

[Means for Solving the Problems, Effect J] The present invention provides an electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a barbylic acid derivative or a thiobarbylic acid derivative represented by the following general formula (I). It is composed of an electrophotographic photoreceptor characterized by the following.

In the formula, Y represents an oxygen atom or a sulfur atom, R1 represents an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group which may be bonded via a bonding group, and R2
and R3 represents a hydrogen atom, an optionally substituted alkyl group or an aryl group, 1m is an integer of 1.2 or 3, and n is an integer of 1 or 2.

Specifically, in the definition of R1, bonding groups include groups such as carbonyl, imino, and nitrilo, and aromatic hydrocarbon groups include groups such as phenyl, naphthyl, phenanthryl, anthranyl, and pyrenyl, and aromatic heterocarbon groups. Ring groups include pyridyl, thienyl, thiazolyl, carbazolyl, benzimidazolyl, benzothiazolyl,
Groups such as furyl and quinolyl are mentioned, and in the definition of R2 and R2, alkyl groups include groups such as methyl and ethyl, aryl groups include groups such as phenyl, naphthyl, and tosyl, and substituents for the above groups include , chlorine atom,
1 halogen atom such as bromine atom, 7 alkyl groups such as methyl, ethyl, phenyl, naphthyl, anthryl, etc.
Examples include a lyl group, a heptaralkyl group such as benzyl, and phenethyl.

Representative examples of the barbylic acid derivatives and thiobarbital acid derivatives represented by the general formula (I) used in the present invention are listed below, but the materials used in the present invention are not limited to these.

Compound Example (1) Compound Example (2) Compound Example (3) Compound Example (4) Compound Example (5) Compound Example (6) Compound Example (7) Compound Example (lO) Compound Example (8) Compound Example (t i) Compound Example (9) Compound Example (12) Compound Example (13) The obtained reaction solution was cooled to room temperature, filtered, washed with methanol, and dried to obtain the target compound example (2). Obtained. Yield 1.3g Aldehyde compound (n) zHs Compound example (14) Compound example (15) Synthesis example (Synthesis of compound example (3)) The following aldehyde compound (II) was placed in a 50 ml eggplant flask.
2.1 g, 30 ml of ethanol was added and heated to 60°C.

Next, 1.0 g of thiobarbylic acid was added, and the electrophotographic photoreceptor of the present invention , the general formula (
It has a photosensitive layer containing a barbylic acid derivative or thiobarbylic acid derivative represented by I) (hereinafter abbreviated as a compound represented by general formula (I)).

The photosensitive layer may take any known form; however, a photosensitive layer containing the compound represented by formula (I) is used as a charge generation layer, and a charge transport layer containing a charge transporting substance is added thereto. Laminated functionally separated photosensitive layers are particularly preferred.

The charge generation layer can be formed by coating a coating solution in which the compound represented by formula (1) is dispersed together with a binder resin in an appropriate solvent on a conductive support by a known method, and the resulting film is It is desirable to form a thin film layer having a thickness of, for example, 5jLm or less, preferably 0.11-1p.

The binder resin used in this case is selected from a wide range of insulating resins or organic photoconductive polymers, including polyvinyl butyral, polyvinylbenzal, polyarylate, polycarbonate polyester, phenoxy resin, cellulose resin, acrylic resin, urethane resin. The content thereof in the charge generation layer is preferably 80% by weight or less, preferably 40% by weight or less.

The solvent used is preferably selected from those that dissolve the resin described above but do not dissolve the charge transport layer or undercoat layer, which will be described later.

Specifically, ethers such as tetrahydrofuran, 1,4-dioxane, and cyclohexanone.

Ketones such as methyl ethyl ketone, amides such as N,N-dimethylformamide, esters such as methyl acetate and ethyl vinegar, aromatic compounds such as toluene, xylene, and chlorobenzene, methanol, ethanol,
-Alcohols such as propatool; aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichlorethylene; and the like.

The charge transport layer is laminated above or below the charge generation layer and has the function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting them to the surface.

The charge transport layer is formed by dissolving a charge transport material in a solvent together with an appropriate binder resin as necessary and coating the layer, and the film thickness is generally 5 to 40 gm.
5 to 30 pm is preferred.

Charge transporting substances include electron transporting substances and regular transporting substances. Examples of electron transporting substances include 24.7-1 linitrofluorenone, 2,4,5.7-titranitrofluorenone, and chloranil.

Examples include electron-withdrawing substances such as tetracyanoquinodimethane and polymerized materials of these electron-withdrawing substances.

Hole-transporting substances include polycyclic aromatic compounds such as pyrene and anthracene, carbazole-based, indole-based, imidazole-based, oxazole-based, thiatool-based, oxadiazole-based, pyrazole-pyrazoline-based, thiadiazole-based, triazole-based compounds, etc. heterocyclic compound, p-
Hydrazone compounds such as diethylaminobenzaldehyde-N,N-diphenylhydrazone, N,N-diphenylhydrazino-3-methylidene-9-ditylcarbazole, α-phenyl-4'-N,N-diphenylaminostilbene, 5- [4-(di-p-tolylamino)benzylidene] -5H-dibenzo[a, d] A styryl compound such as cycloheptene, a benzidine compound, a triarylmethane compound, triphenylamine, or a group consisting of these compounds. Polymers in the main chain or side chains (e.g. poly-N-vinylcarbazole).

polyvinylanthracene, etc.).

In addition to these organic charge transport materials, inorganic materials such as selenium, selenium-tellurium, amorphous silicon, and cadmium sulfide can also be used.

Further, these charge transport materials can be used alone or in combination of two or more.

When the charge transport material does not have film-forming properties, an appropriate binder resin can be used, and specifically, acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, polyacrylamide, polyamide, Examples include insulating resins such as chlorinated rubber, and organic photoconductive polymers such as poly-N-vinylcarbazole and polyvinylanthracene.

Examples of the conductive support include aluminum, aluminum alloy, copper, zinc, stainless steel, titanium, nickel,
Metals such as indium, gold, and platinum can be used.

In addition, such metals can be coated on plastic or conductive particles (e.g. carbon black, silver particles, etc.) by vacuum deposition method, together with a suitable binder resin, on a plastic or metal support or conductive particles. A support material such as plastic or paper impregnated with can be used.

An undercoat layer having healer and adhesive functions can also be provided between the conductive support and the photosensitive layer.

The undercoat layer can be formed of casein, polyvinyl alcohol, nitrocellulose, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, aluminum oxide, or the like.

The thickness of the undercoat layer is suitably 5 pm or less, preferably 0.1 to 3 m.

Another specific example of the present invention is an electrophotographic photoreceptor containing the compound represented by formula (I) and a charge transport material in the same layer. At this time, a charge transfer complex consisting of poly-N-vinylcarbazole and trinitrofluorenone can also be used as the charge transport substance.

The electrophotographic photoreceptor of this example can be formed by coating and drying a solution in which a compound represented by the general formula (I) and a charge transporting substance are dispersed in a suitable resin solution.

General formula (I) used in any electrophotographic photoreceptor
The crystal form of the compound represented by may be amorphous or crystalline, and if necessary, two or more compounds represented by formula (1) may be combined or used in combination with a known charge generating substance. It is also possible to do so.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in a wide range of electrophotographic applications such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making.

[Example] Examples 1 to 15 5 g of methoxymethylated nylon (number average molecular weight 32,000) and 10 g of alcohol-soluble copolymerized nylon (number average molecular weight 29,000) were placed on an aluminum support in methanol 9
A solution dissolved in 5 g was applied using a Meyer bar to form an undercoat layer having a thickness of 1.0 pm after drying.

Next, 5 g of the compound of Compound Example (1) was added to a solution prepared by dissolving 2 g of butyral resin (degree of butyralization: 63 mol %) in 95 g of cyclohexanone, and dispersed in a sand mill for 2 hours. This dispersion was applied onto the previously formed undercoat layer using a Mayer bar and dried to form a charge generation layer so that the Ill thickness after drying was 0.2 μm.

Next, 5 g of a hydrazone compound having the following structure and a compound example (
Electrophotographic photoreceptors corresponding to Examples 2 to 12 were prepared in exactly the same manner using other compounds in place of compound 1).

The electrophotographic photoreceptor thus prepared was tested using an electrostatic copying paper tester (Model 5F-428, manufactured by Yamaguchi Denki ■).
The sample was negatively charged by corona discharge at -5 KV, left in a dark place for 1 second, and then exposed to light using a halogen lamp at an illuminance of 10 lux to evaluate charging characteristics.

The charging characteristics include the surface potential (Vo) and the amount of exposure required to attenuate the surface potential to 1/2 after being left in the dark (El/2).
) was measured. Show the results.

Polymethyl methacrylate (number average molecular weight 100,000) 5g
was dissolved in 40 g of chlorobenzene, and this was applied onto the charge generation layer using a Mayer bar and dried to form a charge transport layer of 20 m thick, thereby producing the electrophotographic photoreceptor of Example 1.

1 (1) 2 (2) 3 (3) 4 (4) 5 (5) 6 (6) 7 (7) 720 1 710 1 650 3 680 2 660 4 750 1 730 1 1 7 0 0 4 5 1 8 (8) 9 (9) 10 (10) 11 (11) 12 (12) 13 (13) 14 (14) 15 (15) 700 3 700 1 690 1 780 3 760 4 720 1 650 1 650 2 2 6 0 7 9 9 9 2 Comparative Example 1 An electrophotographic photoreceptor was prepared in exactly the same manner except that the compound of Compound Example (1) used in Example 1 was replaced with a compound having the following structure, and the charging characteristics were evaluated in the same manner.

El/2: 19.8jLux*sec From the Examples and Comparative Examples, it can be seen that the electrophotographic photoreceptors of the present invention all have sufficient charging ability and excellent sensitivity.

Examples 16 to 20 Using the electrophotographic photoreceptor prepared in Example 1, fluctuations in bright area potential and dark area potential during repeated use were measured.

The photoreceptor was attached to the cylinder of an electrophotographic copying machine equipped with a -6.5 KV corona charger, an exposure optical system, a developer, a transfer charger, a static elimination exposure optical system, and a cleaner.

The amount of variation in dark potential (ΔVo) and the amount of variation in light potential (ΔVo) when the initial dark potential (Vo) and light potential (VL) were set to around -700V and -200V, respectively, and used repeatedly 5,000 times. ΔVL) was measured.

The electrophotographic photoreceptors prepared in Examples 6, 7.9, and 11 were also evaluated in the same manner.

The case corresponding to the photoreceptor of Example 1 will be referred to as Example 16, and the cases corresponding to the photoreceptors of Examples 6, 7, 9, and 11 will be referred to as Examples 17, 18, 19, and 20.

Note that a negative sign in the amount of change in potential represents a decrease in the absolute value of the potential, and a positive sign represents an increase in the absolute value of the potential.

16 1 -15
+2017 6 +5
+518 7
-20 +1019 9
0 +520
11 -20 +5 Comparative Example 2 Regarding the electrophotographic photoreceptor used in Comparative Example 1, Example 16
Potential fluctuations during repeated use were measured using the same method as above. Show the results.

ΔVo knee 215V ΔVL: +105V From the above results, it can be seen that the electrophotographic photoreceptor of the present invention has little potential fluctuation during repeated use.

Example 21 A subbing layer of polyvinyl alcohol having a thickness of 0.5 gm was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film.

On top of this, the film thickness after drying the dispersion of the compound of Compound Example (2) used in Example 2 was 0.2. A charge generating layer was formed by applying the coating using a Mayer bar and drying to form a charge generating layer.

Next, a solution prepared by dissolving 5 g of a styryl compound represented by the following structural formula and 5 g of polycarbonate (weight average molecular weight 55,000) in 40 g of tetrahydrofuran was applied onto the charge generation layer so that the film thickness after drying was 20 lm, and dried. A charge transport layer was formed.

The charging characteristics and durability characteristics of the electrophotographic photoreceptor thus prepared were measured in the same manner as in Example 1 and Example 13. Show the results.

vo knee 720V E l/2: l, 091ux@secΔVo knee 15V ΔVL: +lOV Example 22 An electrophotographic photoreceptor in which the charge generation layer and the direction transport layer of the photoreceptor prepared in Example 21 were coated and laminated in the reverse order. was prepared, and the charging characteristics were evaluated in the same manner as in Example 1. However, the charging polarity was positive.

Show the results.

Vol. By using it in the layer, it has the remarkable effects of high sensitivity and excellent potential stability during repeated use.

Claims (1)

[Claims] 1. In an electrophotographic photoreceptor having a photosensitive layer on a conductive support, the photosensitive layer contains a barbituric acid derivative or a thiobarbituric acid derivative represented by the following general formula (I). Characteristic electrophotographic photoreceptor. General formula (I) In the formula, Y represents an oxygen atom or a sulfur atom, and R_1 represents an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group that may be bonded via a bonding group. ,R
_2 and R_3 represent a hydrogen atom, an optionally substituted alkyl group or an aryl group, m is an integer of 1, 2 or 3, and n is an integer of 1 or 2. 2. Claim 1, wherein the photosensitive layer comprises at least two layers: a charge generation layer containing a barbituric acid derivative or a thiobarbituric acid derivative represented by the general formula (I) and a charge transport layer.
The electrophotographic photoreceptor described above.