JPH0261643A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To form the subject body with high sensitivity by incorporating a specified compd. in the sensitive body. CONSTITUTION:The compd. shown by formula I is incorporated in the sensitive body. In formula I, R1 - R4 are each alkyl or alkoxy group or halogen or hydrogen atom, the groups R1 - R4 are not all hydrogen atom, and are at least two kinds of substitutional groups. The concrete example shown by formula I is exemplified by a compd. shown by formula II. As the compd. shown by formula I plays a role of the excellent effective component of the sensitive body, the sensitive body with the high sensitivity is obtd.

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

However, poly-N-vinylcarbazole lacks flexibility, its coating is hard and brittle, and is prone to cracking and peeling. If this drawback is improved, the residual potential becomes large during the electrophotographic process, and with repeated use, the residual potential accumulates, gradually increasing the fog and damaging the copied image.

Furthermore, low-molecular organic photoconductive compounds generally do not have film-forming ability, and are formed into films with the aid of appropriate binders.

Therefore, the physical properties or photosensitivity characteristics of the film can be controlled to some extent by selecting the type and composition ratio of the binder used, but the types of organic photoconductive compounds that have high compatibility with the binder are limited. In reality, there is a dearth of binders that can be used in the construction of the photosensitive layer of photoreceptors, particularly electrophotographic photoreceptors.

For example, the 2,5
-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 phenothiazine 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 No. 62-201450 has relatively good charge retention and sensitivity, but is not satisfactory in terms of durability during repeated use and compatibility with binders.

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 reduce fatigue deterioration due to repeated use and maintain stable characteristics over a long period of time when used as a photoreceptor for repetitive transfer type electrophotography 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.

Furthermore, another object of the present invention is to have high compatibility with the binder;
An object of the present invention is to provide an electrophotographic photoreceptor in which crystallization does not easily occur on the photoreceptor surface.

[Means to solve the problem]

As a result of repeated research in line with the above purpose, the following general formula (I)
It has been discovered that the compound represented by the following can function as an excellent active ingredient for electrophotographic photoreceptors, and constitutes the present invention.

[Structure of the invention]

An electrophotographic photoreceptor comprising a compound represented by the following general formula [I].

General formula [I] In the formula, R,, R,, R, and R4 each represent an alkyl group, an alkoxy group, a halogen atom substituent or a hydrogen atom, and all of R, -R, and R are hydrogen atoms. It is occupied by at least two or more of the above substituents.

Then the general formula A specific example of a compound represented by Illustrate.

: Exemplary compound: Synthesis example (Exemplary compound (1)) 4.4'-diamino(N,N-p-ditolyl)stilbene8. Og and p-chloro-iodobenzene 10-
2.6 g of 5gs copper powder and 11.8 g of potassium carbonate are mixed and heated. Stir at 200-220°C for about 24 hours. The reaction product was extracted with 500 nQ of toluene, separated and purified by column chromatography. Objective 6.8
I got g.

Various structures of electrophotographic photoreceptors are known, but
The electrophotographic photoreceptor of the present invention can take any of these forms.

Usually, the configuration is as shown in FIGS. 1 to 6. Figures 1 and 2
In the figure, a photosensitive layer 4 consisting of a laminate of a carrier generating layer 2 containing a carrier generating substance as a main component and a carrier transporting layer 3 containing a carrier transporting substance as a main component is provided on a conductive support l. 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 can be obtained.

Further, in the present invention, as shown in FIGS. 5 and 6, a photosensitive layer 4 formed by dispersing the carrier-generating substance 7 in a layer 6 mainly composed of a carrier-transporting substance is placed 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 flavanmelons (5) Quinacridone dyes (6) Bisbenzimidazole dyes (7) Impropatur (8) Squarelillium dyes (9) Cyanine dyes (10) 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) Cd3%Cd5e (16) Examples include pyrylium salt dyes and thiapyrylium salt dyes, 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) Polyester (p-3) Methacrylic resin (P-4) Acrylic resin (P-5) Polyvinyl chloride (p-6) Polyvinylidene chloride (P-7) Polystyrene (P-7) -8) Polyvinyl acetate (P -9) Styrene-butadiene copolymer (P
-10) Vinylidene chloride-acrylonitrile copolymer (P-11) Vinyl chloride-vinyl acetate copolymer (P-11) Vinylidene chloride-vinyl acetate copolymer (P-11)
P-12) Vinyl chloride-vinyl acetate-maleic anhydride copolymer (p-13) Silicone resin (P-14) Silicone-alkyd resin (P-12)
-15) Phenol formaldehyde resin (P -
16) Styrene-alkyd resin (P-17)
Poly-N-vinylcarbazole (P-18) Polyvinyl butyral (P-19) Polyvinyl 7olmar These binder resins can be used alone or as 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 l.

2-dichloroethane, l,2-dichloropropane, 1.
Examples include 1.2-trichloroethane, 1,1.14-trichloroethane, trichlorethylene, tetrachloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, inpropatol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve, etc. , 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 o-too:i~500:0~500.
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 carrier transport substance is preferably 20 to 200 parts by weight per 100 parts by weight of the binder resin in the carrier transport layer.
- Particularly preferably 30 to 150 parts by weight.

The thickness of the carrier generation layer formed as described above is
Preferably 0.01-10 μm, 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 μm.

On the other hand, when the photoreceptor of the present invention has a monolayer functionally separated structure, the weight ratio of binder:carrier generating substance:carrier transporting substance in the photosensitive layer is preferably 0 to 100:l to 500:l to 500. The thickness of the photosensitive layer is 5 to 50
μm is preferred, particularly preferably 5 to 30 μm.

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, diethylamine, diisohexylamine, diisodecylamine, diisopentylamine, dioctylamine, Examples include diisooctylamine, 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 (■): Hindered phenols dibutylhydroxytoluene, 2.2'-methylenebis(6-t-butyl-4-methylphenol), 4.4'
-butylidenebis(6-t-butyl-3-methylphenol), 4.41-thiobis(6-1-butyl-3-methylphenol), 2.2/-butylidenebis(6-t
-butyl-4-methylphenol), a-tocopherol, β-tocopherol, 2.2.4-tolumethyl-
6-Hydroxy7-t-butylchroman, pentaerythyltetrakis [3-(3,5-di-t-butyl-4
-hydroxyphenyl)propionate], 2.2'-
Thiodiethylene bis[3-(3,5-di-butyl-4
-hydroxyphenyl)propionate], 1,6-hexanediolbis[3-(3,5-di-t-butyl-
4-hydroxyphenyl) propionate], butylhydroxyanisole, dibutylhydroxyanisole,
l-[2-((3,5-di-butyl-4-hydroxyphenyl)propionyloxy)ethyl]-4-[3-(
3,5-thiefthyl-4-hydroxyphenyl)flopionyloxy]-2,2,6,6-titramethylpiperidyl, and the like.

Group (n): para-phenylenediamines N-phenyl-N'-isoglo and p-phenylenediamine, N,N'-di-5eC-butyl-p-7 22-diamine, N-phenyl-N-sec- Butyl-p-
722 diamine, N,N'-diisopropyl-p-
722 diamine, N,N'-dimethyl-N,N'-
di-butyl-p-phenylenediamine and the like.

Group (■): Hydroquinones 2.5-di-t-octylhydroquinone, 2.6-sidodecylhydroquinone, 2-dodecylnohydroquinone, 2-dodecyl-5-chlorno\idoquinone, 2-t
-octyl-5-methylhydroquinone, 2-(2-octadecenyl)-5-methylhydroquinone, etc.

Group (■): Organic sulfur compounds dilauryl-3,3'-thiodipropionate, distearyl-3,3/-thiodipropionate, ditetradecyl-3,3'-thiodipropionate, etc.

Group (V): Organophosphorus compounds such as triphenylphosphine, tri(nonylphenyl)phosphine, tri(dinonylphenyl)phosphine, tricresylphosphine, tri(2,4-dibutylphenoxy)phosphine.

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, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, 3-nitroheptadalic anhydride, 4
-Nitrophthalic anhydride, pyromellitic anhydride, mellitic anhydride, tetracyanoethylene, tetracyamiquinodimethane, 0-dinitrobenzene, 1-dinitrobenzene,
1.3.5-trinitrobenzene, varanitrobenzonitrile, picrin chloride, quinone chlorimide, chloranil, brumanil, dichlorodicyanobarabenzoquinone, anthraquinone, dinitroanthraquinone, 2.
7-cinitrofluorenone, 2.4.7-)linitrofluorenone, 2,4,5.7-tetranitrofluorenone, 9-fluorenylidene [dicyanomethylenemalonodinitrile], polynitro-9-fluorenylidene-[dicyanomethylenemalonodinitrile] dinitrile], picric acid, O-
Nitrobenzoic acid, p-nitrobenzoic acid, 3.5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,5-dinitrosalicylic acid, 7-talic acid, mellitic acid, and other compounds with high electron affinity. can be mentioned.

The amount of the electron-accepting substance added is carrier-generating substance:electron-accepting substance-too:o,oi~200, preferably 100:0.1-100.

The electron-accepting substance may be added to the carrier transport layer. The amount of electron-accepting substance added to this layer is carrier transport substance:electron-accepting substance-100:0.01-10 by weight.
0, 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 later, it has excellent charging characteristics, sensitivity characteristics, and image forming characteristics, and especially shows little fatigue deterioration even when used repeatedly, 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 applied fields such as photoreceptors for 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 μl thick layer of vinyl chloride-vinyl acetate-maleic anhydride copolymer “S-LEC MF-10J (manufactured by Tsukisui Kagaku Co., Ltd.) was placed on a conductive support having aluminum vapor-deposited on a polyester film. An intermediate layer of Dibromo Anthron "Monolite Red 2 Y
J (C, I, No. 59300100) Ig
was added to 30 mQ of 1,2-dichloroethane and dispersed in a ball mill. 1.5 g of polycarbonate "Panlite L-1250J (manufactured by Ondai Kagaku Co., Ltd.) was dissolved in the resulting dispersion, and the thoroughly mixed coating solution was dried. A carrier generation layer was formed by coating the film to a thickness of 2 μm.

On top of that, 5 g of exemplified compound (1) and polycarbonate r
Z-200J (Mitsubishi Gas Chemical Co., Ltd.) A solution prepared by dissolving Z-200J (Mitsubishi Gas Chemical) in Tetrahydro7ran 80ffIQ was applied to form a carrier transport layer such that the film thickness after drying was 15 μm, thereby producing a 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, it was left in the dark for 5 seconds, and then halogen lamp light was irradiated so that the illumination intensity on the photoreceptor surface was 2 Qux, and the initial surface potential vA and the half-decrease exposure amount E 1/2 were set. I asked for it. Further, the residual potential V after exposure with an exposure amount of 3012 ux sea was determined.

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

Table 1 Examples 2 to 6 Photoreceptor Table 2 Table 3 Example 7 Comparative Example (1) Carrier transport A comparative photoreceptor was prepared in the same manner as in Example 1, except that the following compound T-1 was used as the substance.

Regarding this comparative photoreceptor, in Example 1, 2 g of the bisazo pigment having the above structure and 2 g of the polycarbonate resin "Panlite L-1250J" were mixed in 100 mff of 1,2-dichloroethane and dispersed with a sand grinder for 8 hours. This dispersion was placed on a conductive support made of aluminum vapor-deposited on a polyester film so that the thickness after drying was lp.
Apply it to H in a stroking motion.

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.

Table 4 T-2 Examples 8 to 12 Photoreceptors were prepared in the same manner as in Example 7, except that the exemplified compounds shown in Table 5 below were used instead of exemplified compound (1),
It was measured.

When this photoreceptor was measured in the same manner as in Example 1, the results shown in Table 6 were obtained.

Table 6 Comparative Example (2) A comparative photoreceptor was prepared in the same manner as in Example 7 except that the following compound T-2 was used as a carrier transport substance.

Example 13 On a conductive support made of polyethylene terephthalate with a thickness of 100 μm on which aluminum was vapor-deposited, an undercoat with a thickness of about 0.2 μm made of a p-hydroxystyrene polymer “Maruzen Resin Ml (manufactured by Maruzen Sekiyu Co., Ltd.) was applied. formed a layer.

Next, polycarbonate resin “Panlite L-125
0J (manufactured by Ondai Kasei Co., Ltd.) 0.5g, β-type copper 7 talocyanine 1g, and 1,2-dichloroethane 100m12
A dispersion obtained by mixing and dispersing in a sand mill for 10 hours is coated on the undercoat layer by a wire spar coating method,
It was dried at 100°C for 10 minutes to form a carrier generation layer with a thickness of 0.2 μm.

Furthermore, as a carrier transport substance, exemplified compound (27)
A solution prepared by dissolving 12 g of acrylic resin "Dianaru BR-80" (manufactured by Mitsubishi Rayon Co., Ltd.) in 100 ml of 1,2-dichloroethane was applied onto the carrier generation layer using a doctor blade, and the solution was coated with a doctor blade at a temperature of 90°C.
A carrier transport layer having a thickness of 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 -Bix equipped with a laser light source (output 1IIIW) with a wavelength of 780±1 nm
Using a modified machine of 1550 MRJ (manufactured by Konica Corporation), the grid voltage was adjusted so that the charging potential was 1600 V, and evaluation was performed. Table 7 of the evaluation results of the actual internal potential of the photoreceptor 7 ■H: Surface potential of the unexposed area ■L: Surface potential of the exposed area As is clear from the results above, the photoreceptor of the present invention has sufficient resistance to the semiconductor laser light source. It was found that it has a high sensitivity.

As is clear from the above Examples and Comparative Examples, the photoreceptor of the present invention is superior in sensitivity and durability than the comparative photoreceptor.

[Brief explanation of the drawing]

1 to 6 are cross-sectional views of the photoreceptor of the present invention. 1...Support, 2...Carrier generation layer,
3... Carrier transport layer, 4... Photosensitive layer, 7... Carrier generating substance, 8... Protective layer.

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor characterized by containing a compound represented by the following general formula [I]. General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc. Not all R_4 are hydrogen atoms, but are occupied by at least two or more of the above substituents. ]