JPH0256559A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve thermal stability and durability by incorporating a specific compd. into the photosensitive body. CONSTITUTION:This photosensitive body contains the compd. expressed by formula I. In formula, R2, R2 denote an aryl group which may have a substituent; X1 to X4 denote a hydrogen atom, halogen atom, alkyl group, alkoxy group; (n) denotes 1 or 2 integer. The aryl group of R1, R2 denote a phenyl group, alpha-naphthyl group, beta-naphthyl group, etc.; the substituent for these groups denotes a halogen atom, alkyl group, butyl group, etc.; the alkyl group of X1 to X4 includes a methyl group, ethyl group, propyl group, etc. The fatigue deterioration by repetitive use is decreased in this way and the stable characteristics are maintained over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having a photosensitive layer containing a carrier-generating substance and a carrier-transporting substance.

[Prior art]

Conventionally, electrophotographic photoreceptors having a photosensitive layer containing as a main component an inorganic photoconductor such as selenium, zinc oxide, cadmium sulfide, or silicon have been widely known. However, these are not necessarily satisfactory in terms of properties such as thermal stability and durability, and there are also problems in manufacturing and handling.

On the other hand, photoreceptors having a photosensitive layer containing an organic photoconductive compound as a main component are relatively easy to manufacture, inexpensive, easy to handle, and are generally more heat sensitive than selenium photoreceptors. It has many advantages such as excellent stability, and as such an organic photoconductive compound, poly-N
-Vinylcarbazole is the most well-known, and photoreceptors having a photosensitive layer mainly composed of a charge transfer complex formed from vinylcarbazole and a Lewis acid such as 2.4.7-trinitro-9-fluorenone have already been put into practical use. has been made into

On the other hand, photoconductors are known that have a multilayer type or single layer type functionally separated photoconductor layer in which the carrier generation function and the carrier transport function of the photoconductor are shared by separate substances. A photoreceptor having a photosensitive layer consisting of a carrier generation layer consisting of a thin layer of regular selenium and a carrier transport layer containing boryl N-vinylcarbazole as a main component has already been put into practical use.

However, poly-N-vinylcarbazole lacks flexibility, its film is hard and brittle, and is prone to cracking and peeling, and photoreceptors using it have poor durability and require the addition of plasticizers. If the disadvantage of the lever is improved, the residual potential increases during the electrophotographic process, and with repeated use, the residual potential accumulates, gradually increasing the fog and damaging the copied image.

In addition, since low-molecular organic photoconductive compounds generally do not have film-forming ability, they are used in combination with an appropriate binder, and the physical properties or photosensitivity of the film can be controlled to a certain extent by selecting the binder type, composition ratio, etc. Although it is preferable in terms of
The types of organic photoconductive compounds that have high compatibility with binders are limited, and there are actually few binders that can be used in the construction of photosensitive layers of photoreceptors, particularly electrophotographic photoreceptors.

For example, 2.5 as described in U.S. Pat. No. 3.189.447.
-bis(p-diethylaminophenyl)-1,3,4-
Oxadiazole has low compatibility with binders commonly used as materials for the photosensitive layer of electrophotographic photoreceptors, such as polyester and polycarbonate, and is mixed in the ratio required to adjust the electrophotographic properties to form the photosensitive layer. As a result, oxadiazole crystals begin to precipitate at temperatures of 50° C. or higher, resulting in a disadvantage that electrophotographic properties such as charge retention and sensitivity deteriorate.

On the other hand, the diarylalkane derivatives described in U.S. Pat. If it is suitable for the photosensitive layer of a commercial photoreceptor, it has the disadvantage that the sensitivity of the photosensitive layer gradually decreases.

Also, U.S. Patent No. 3,274,000, Japanese Patent Publication No. 47-36
No. 428 describes different types of 7-functional notthiazine derivatives, but all of them have the drawbacks of low photosensitivity and low stability during repeated use.

Also, JP-A No. 58-65440, No. 58-190953
The stilbene compound described in the above publication has relatively good charge retention and sensitivity, but is not satisfactory in terms of durability after repeated use.

The reality is that a carrier transporting material having practically satisfactory characteristics for producing an electrophotographic photoreceptor has not yet been found.

[Purpose of the invention]

An object of the present invention is to provide a highly sensitive photoreceptor.

Another object of the present invention is to provide an electrophotographic photoreceptor with high sensitivity and low residual potential.

Another object of the present invention is to use it as a photoreceptor for electrophotography of a repetitive transfer type in which charging, exposure, development, and transfer steps are repeated. An object of the present invention is to provide an electrophotographic photoreceptor having excellent durability over a long period of time.

[Means to solve the problem]

As a result of intensive research in line with the above purpose, the following general formula C
It has been found that an electrophotographic photoreceptor containing at least one of the compounds represented by I) has excellent utility.

General formula (r) In each of the structural units represented by the formula, R4 and R2 are independently
represents an aryl group which may have a substituent, x1 to X4
represents a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group. n represents an integer of 1 or I;

The aryl group of R,,R2 is phenyl group, a-
Examples include naphthyl group and β-su7tyl group. Substituents for these groups include halogen atoms (fluorine atom, chlorine atom, bromine atom, iodine atom), alkyl groups (methyl group, ethyl group, propyl group, butyl group, etc.), alkoxy groups (methoxy group, ethoxy group, etc.). , propoxy group, butoxy group), and substituted amino groups.

X l+ X 2. The alkyl group for X s and x4 is a methyl group, ethyl group, propyl group, or butyl group, the halogen atom is a fluorine atom, chlorine atom, bromine atom, or iodine atom, and the alkoxy group is a methoxy group.

Ethoxy, propoxy, butoxy and the like are preferred.

Next, a compound represented by the general formula (I) according to the present invention: Exemplary compound: Synthesis example (Exemplary compound (3)) 2.9 g of potassium t-butoxide was added to N,N-dimethylformamide 2oIIIQ at room temperature with nitrogen. Dispersed under atmosphere.

Dissolved. Thereto were 8.7 g of 4,4'-bis(diethylmethylphosphite)-biphenyl and 11 g of 4-methyl-4'-carbaldehyde-triphenylamine. Og to N, N-
Dissolved in 30 mQ of dimethylformamide, about 3
It was added dropwise over 0 minutes. Thereafter, the mixture was stirred at room temperature for 3 hours.

The reaction solution was poured into 500 mL of water, and the precipitate was collected by filtration, washed with water, and dried. The crystals were recrystallized from toluene and acetone to obtain 8.6 g of pale yellow powder.

Melting point 124-127°C Parent ion peak (M+) of target object in FD-mass measurement
720, C5J44Nz Mw-720 Electrophotographic photoreceptors are known to have various structures, and the electrophotographic photoreceptor of the present invention can take any of these structures.

Usually, the configuration is as shown in FIGS. 1 to 6. Figures 1 and 2
In the figure, a conductive support! A photosensitive layer 4 made of 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 is provided thereon. As shown in FIGS. 3 and 4, this photosensitive layer 4 may be provided via an intermediate layer 5 provided on a conductive support. When the photosensitive layer 4 has a two-layer structure in this way. A photoreceptor having the most excellent electrophotographic properties is obtained. Further, in the present invention, as shown in FIGS. 5 and 6, a photosensitive layer 4 comprising the carrier-generating substance 7 dispersed in a layer 6 mainly composed of a carrier-transporting substance is formed on a conductive support l. It may be provided directly or via the intermediate layer 5. Further, in the present invention, a protective layer 8 may be provided as the outermost layer as shown in FIG.

Examples of carrier-generating substances used in the carrier-generating layer of the photosensitive layer according to the present invention include the following.

(1) Azo dyes such as monoazo dyes, disazo dyes, and trisazo dyes (2) Perylene dyes such as perylenic anhydride and perylenic acid imide (3) Indigo dyes such as indigo and thioindigo (4) Anthraquinone, pyrenequinone and polycyclic quinones such as flavan melons (5), quinacridone dyes (6), bisbenzimidazole dyes (7), induthrone dyes (8), squarelillium dyes (9), cyanine dyes (lO), and azulenium dyes. (11) Triphenylmethane pigments (12) Amorphous silicon (13) Phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine (14) Selenium, selenium-tellurium, selenium-arsenic (
15) CdS, Cd5e (16) Pyrylium salt dyes, thiapyrylium salt dyes, and the like, which can be used alone or as a mixture of two or more.

Preferable examples include (1), (4), (8), and (13).

Since the stilbene derivative used in the present invention does not have the ability to form a coating by itself, a photosensitive layer is formed by combining various binders.

Although any binder can be used here, it is preferable to use a hydrophobic, high dielectric constant, electrically insulating film-forming polymer. Examples of such high molecular weight polymers include, but are not limited to, the following.

(P-1) Polycarbonate (p-2) CP-3) (P-4) (P-5) (P-6) (P-7) (p-8) (P-9) (P-10) (p -11) (P -12) (p -13) (P -14) (p -15) (p -16) (p -17) (P -18) (p -19) Polyester methacrylic resin Acrylic resin Polyvinyl chloridePolyvinylidene chloridePolystyrenePolyvinylacetateStyrene-butadiene copolymerVinylidene chloride-acrylonitrile copolymerVinyl chloride-vinyl acetate copolymerVinyl chloride-vinyl acetate-maleic anhydride copolymerSilicone resinSilicone-alkyd resinPhenol formaldehyde resin Styrene-alkyd resin Poly-N-vinylcarbazole Polyvinyl butyral Polyvinyl resin These binder resins can be used alone or in a mixture of two or more.

Examples of solvents for forming the carrier transport layer of the present invention include N,N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, and (2).

2-dichloroethane, 1,2-dichloropropane, 1,
1゜2-) IJ chloroethane, 1.1.1-trichloroethane, trichlorethylene, tetrachloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, inpropatol, ethyl acetate,
Examples include butyl acetate, dimethyl sulfoxide, methyl cellosolve, etc., and they can also be used in combination.

When the photoreceptor of the present invention has a laminated structure, the weight ratio of binder:carrier generating substance:carrier transporting substance in the carrier generating layer is preferably 0 to 100:1 to 500:O to 500.
It is.

If the content of the carrier-generating substance is less than this, the photosensitivity will be low and the residual potential will increase, and if it is more than this, the dark decay and acceptance potential will decrease.

Further, the amount of the carrier transport substance is preferably 20 to 200 parts by weight, particularly preferably 30 to 150 parts by weight, per 100 parts by weight of the binder resin in the carrier transport layer.

The thickness of the carrier generation layer formed as described above is
Preferably 0.01-10 μm1, particularly preferably 0.1
~5 μm.

Further, the thickness of the carrier transport layer to be formed is preferably 5 to 50 μm, particularly preferably 5 to 30 μI.

On the other hand, when the photoreceptor of the present invention has a single-layer functionally separated structure, the weight ratio of the pine mite carrier-generating substance to the carrier-transporting substance in the photosensitive layer is preferably 0 to 100:1 to 500:1 to 500. The thickness of the photosensitive layer is preferably 5 to 50 μm, particularly preferably 5 to 3077+11.

The conductive support used in the electrophotographic photoreceptor of the present invention is a metal plate including an alloy, a metal drum or a conductive polymer, a conductive compound such as indium oxide, aluminum including an alloy, palladium, gold, etc. Apply a thin layer of metal,
Examples include paper and plastic films made conductive by vapor deposition or lamination. As an intermediate layer such as an adhesive layer or a barrier layer, in addition to the high molecular weight polymer used as the binder resin, polyvinyl alcohol,
Organic polymer substances such as ethyl cellulose and carboxymethyl cellulose, or aluminum oxide are used.

Organic amines can be added to the photosensitive layer of the present invention for the purpose of improving the carrier-generating function of the carrier-generating substance, and it is particularly preferable to add a secondary amine.

Examples of such secondary amines include dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, diisobutylamine, cyamylamine, diisoamylamine, dihequinylamine, diisohexylamine, diisotylamine, diisopentylamine, dioctylamine, diisobutylamine, Examples include isooctylamine, dinonylamine, diisononylamine, didecylamine, diisodecylamine, diisodecylamine, diisomonodecylamine, didodecylamine, diisododecylamine, and the like.

The amount of organic amines to be added is preferably 1 times or less, preferably 0.2 to 0.005 times the amount of the carrier generating substance.

Further, an antioxidant for the purpose of preventing ozone deterioration may be added to the photosensitive layer of the present invention.

Typical examples of such antioxidants are shown below, but the invention is not limited thereto.

Group (I): Hindered phenols dibutylhydroxytoluene, 2,2'-methylenebis(6-t-butyl-4-methylphenol), 4,4'
-butylidenebis(6-t-butyl-3-methylphenol), 4.47-thiobis(6-7-butyl-3-methylphenol), 2.2'-butylidenebis(6-t-butyl-3-methylphenol),
-phthyl-4-methylphenol), α-tocopherol, β-tocopherol, 2.2.4-tolumethyl-
6-Hydroxyd-L-butylchroman, pentaerythyltetrakis [3-(3,5-di-t-butyl-4-
hydroxyphenyl)brobionate], 2,21-thiodiethylenebis[3-(3,5-di-monobutyl-4
-hydroxyphenyl)propionate], 1,6-hexanediolbis[3-(3,5-di-t-butyl-
4-hydroxyphenyl) propionate], butylhydroxyanisole, dibutylhydroxyanisole,
1-[2-((3,5-di-butyl-4-hydroxyphenyl)propionyloxy)ethyl]-4-[3-(
3,5-di-butyl-4-hydroxyphenyl)propionyloxy]-2,2,6,6-titramethylpiperidyl, and the like.

(11) Group: Paraphenylenediamines N-phenyl-
N'-isopropyl-p-7 22-diamine, N,N
'-5ec-butyl-p-phenylenediamine, N
-Phenyl-N-sea-butyl-p-phenylenediamine, N,N'-diisopropyl-p-7 22-diamine, N,N'-dimethyl-N,N'-di-butyl-p
-722 diamine, etc.

(1) Group: Hydroquinones 2.5-di[-octylhydroquinone, 2.6-sidedecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone , 2-(2-octadecenyl)-5-methylhydroquinone, etc.

Group (IV): organic sulfur compounds dilauryl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, ditetradecyl-3,3'-thiodipropionate, etc.

Group (V): Organic phosphorus compounds triphenylphosphine, tri(nonylphenyl)phosphine, tri(dinonylphenyl)phosphine, tricresylphosphine, tri(2,4-dibutylphenoxy)phosphine, etc.

These compounds are known as antioxidants for rubber, plastics, oils and fats, and are easily available commercially.

These antioxidants may be added to any of the carrier generation layer, carrier transport layer, or protective layer, but are preferably added to the carrier transport layer.

In that case, the amount of antioxidant added is 10 parts of the carrier transport substance.
0.1-100 parts by weight, preferably 1 part by weight
~50 parts by weight, particularly preferably 5 to 25 parts by weight.

In the present invention, the carrier generation layer may contain one or more electron-accepting substances for the purpose of improving sensitivity, reducing residual potential or fatigue during repeated use, etc.

Examples of electron-accepting substances that can be used here include succinic anhydride, maleic anhydride, dibromaleic anhydride, 7-talic anhydride, tetrachlorophthalic anhydride, tetrabrom-7-thalic anhydride, 3-nitro 7-tallic anhydride. acid, 4
- Nitrophthalic anhydride, pyromellitic anhydride, mellitic anhydride, tetracyanoethylene, tetracyamiquinodimethane, 0-dinitrobenzene, m-dinitrobenzene,
1,3.5-trinitrobenzene, paranitrobenzonitrile, pi,talin chloride, quinone chlorimide,
Chloranil, brumanil, dichlordicyanobara benzoquinone, anthraquinone, dinitroanthraquinone, 2
．． 7-sinitrofluorenone, 2,4.7-trinitrofluorenone, 2.4.5.7-tetranitrofluorenone, 9-fluorenylidene [dicyanomethylenemalonodinitrile], polynitro-9-fluorenylidene-[
dicyanomethylenemalonodinitrile], picric acid, 0
-nitrobenzoic acid, p-nitrobenzoic acid, 3.5-;
Nitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,5-dinitrosalicylic acid, phthalic acid,
Examples include mellitic acid and other compounds with high electron affinity.

The amount of the electron-accepting substance added is carrier-generating substance:electron-accepting substance-100 in a weight ratio of 0.01 to 200, preferably too: 0.1 to 100.

The electron-accepting substance may be added to the carrier transport layer. The amount of electron-accepting substance added to this layer is carrier transporting substance:electron-accepting substance=100:0.01-100 in weight ratio.
, preferably 100:0.1-50.

In addition, the photoreceptor of the present invention may also contain, if necessary, an ultraviolet absorber or the like for the purpose of protecting the photosensitive layer, and may also contain a dye for color sensitivity correction.

The electrophotographic photoreceptor of the present invention has the above structure,
As is clear from the Examples described below, it has excellent charging characteristics, sensitivity characteristics, and image forming characteristics, and particularly shows little fatigue deterioration even after repeated use, and has excellent durability.

Furthermore, the electrophotographic photoreceptor of the present invention can be used in electrophotographic copying machines, as well as
Laser, cathode ray tube (CRT), light emitting diode (L
It can also be widely used in reaction fields such as photoreceptors of printers using ED) as a light source.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the embodiments of the present invention are not limited thereby.

Example 1 A 0.05 μm thick film made of vinyl chloride-vinyl acetate maleic anhydride copolymer [S-LEC MF-10 (manufactured by Tsukisui Kagaku Co., Ltd.)] was placed on a conductive support having aluminum vapor-deposited on a polyester film. Add 1g of the intermediate layer to 30v2 of 1,2-dichloroethane and disperse with a ball mill.
Dissolve 1.5g of 1250J (manufactured by Ondai Kagakusha),
A carrier generation layer was formed by applying a sufficiently mixed coating solution to a dry film thickness of 2 μm.

On top of that, 5 g of exemplified compound (3) and polycarbonate r
A solution of 10 g of Z-200J (Mitsubishi Gas Chemical) dissolved in 80 vaQ of tetrahydro-7rane was coated to form a carrier transport layer so as to have a dry film thickness of 15 μm, thereby producing the photoreceptor of the present invention.

The photoreceptor obtained as described above was manufactured by Kawaguchi Electric Co., Ltd.
The following characteristics were evaluated using PA-8100. After charging with a charging voltage of -6 KV for 5 seconds, the photoreceptor was left in the dark for 5 seconds, and then halogen lamp light was irradiated so that the illuminance on the photoreceptor surface was 2 (lux), and the initial surface potential V A% was halved by exposure i E 1/ 2 was determined. Also, the residual potential VR after exposure with an exposure amount of 304 uxsec was determined.

Further, similar measurements were repeated 1000 times. The results were as shown in Table 1.

Table 1 Table 2 Examples 2 to 12 Photoreceptors were prepared and measured in the same manner as in Example I, except that the exemplified compounds shown in Table 2 below were used instead of exemplified compound (3).

Margin Comparative Example (1) A comparative photoreceptor was prepared in the same manner as in Example 1 except that the following compound T-1 was used as a carrier transporting substance.

When this comparative photoreceptor was measured in the same manner as in Example 1, the results shown in Table 3 were obtained.

Table 3 Table 4 Example 13 Examples 14 to 24 Photoreceptors were prepared and measured in the same manner as in Example 13, except that the exemplified compounds shown in Table 5 below were used instead of exemplified compound (3).

1.2 g of bisazo pigment having the above structure and 2 g of polycarbonate resin [Panlite L-1250J]
- It was mixed with 100 ml of dichloroethane and dispersed for 8 hours using a sand grinder. This dispersion was applied onto a conductive support made of a polyester film deposited with aluminum so that the thickness after drying was 1 μm.

A photoreceptor was prepared in the same manner as in Example 1, except that Exemplary Compound (3) was used as the carrier transport material. This photoreceptor was also measured in the same manner as in Example 1, and the results shown in Table 4 were obtained.

Comparative Example (2) A comparative photoreceptor was prepared in the same manner as in Example 13, except that the following compound T-2 was used as a carrier transport substance.

Tτ2 This photoreceptor was measured in the same manner as in Example 1, and the results shown in Table 6 were obtained.

Table 6 Example 25 On a conductive support made of polyethylene terephthalate with a thickness of 100 μm on which aluminum was vapor-deposited, an approximately 0.2 μm thick layer made of a p-hydroxystyrene polymer “Maruzen Resin MJ (manufactured by Maruzen Sekiyu Co., Ltd.)” was placed. A subbing layer was formed.

Next, polycarbonate resin [Panlite L-125
0J (manufactured by Ondai Kasei Co., Ltd.) 0.5g, β-type copper phthalonanine 1g, and ■,2-dichloroethane 100m12
A dispersion obtained by mixing and dispersing in a sand mill for lθ time is coated on the undercoat layer by a wire bar coating method,
It was dried at 100°C for 10 minutes to form a carrier generation layer with a thickness of about 0.2 μm.

Furthermore, exemplified compounds (2L) are used as carrier transport substances.
A solution prepared by dissolving 12 g of acrylic resin [Dianaru BR-80'' (manufactured by Mitsubishi Rayon Co., Ltd.)] in 100 mQ of 1,2-dichloroethane was applied onto the carrier generation layer using a doctor blade, and the mixture was heated at 90'C for 1 hour. A carrier transport layer having a thickness of about 20 μm was formed by drying for a period of time, thereby producing a photoreceptor of the present invention.

Regarding the photoconductor of the present invention, r U -Bix1 equipped with a laser light source (output in+W) with a wavelength of 780±l nm
Using a modified 550MRJ (manufactured by Konica Corporation),
The grid voltage was adjusted so that the charging potential was 1600 V and evaluated. The evaluation results of the actual internal potential of the photoreceptor are shown in Figure 7 below.

Table 7 8...Protective layer.

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor comprising at least one compound represented by the following general formula [I]. General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc.
1 to X_4 represent a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group. n represents an integer of 1 or 2. ]