JPH0394259A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To form the electrophotographic sensitive body having a high sensitivity by providing a layer contg. one of specific compds. CONSTITUTION:The layer contg. the compd. expressed by formula I is provided. In the formula I, Ar<1> to Ar<6> denote a substd. or unsubstd. alkyl group, aryl group, aralkyl group; R denotes a hydrogen atom, halogen atom, the following two alkyl groups and alkoxy group which may have a substituent. More specifically, the alkyl group of Ar<1> to Ar<6> is exemplified by methyl, ethyl, propyl, butyl, etc., the aryl group is exemplified by phenyl, naphthyl, etc., and the aralkyl group is exemplified by benzyl, phenethyl, etc. The photosensitive body having the excellent sensitivity characteristics is obtd. in this way.

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 are 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 photoreceptor layer mainly composed of an organic photoconductive compound are relatively easy to manufacture, inexpensive, and easy to handle, and are generally more expensive than selenium photoreceptors. It has many advantages such as excellent thermal stability, and as such an organic photoconductive compound, polyN
-Vinyl rubber is the most well known, and it is a photosensitive material that has a photosensitive layer mainly composed of a charge transfer complex formed by a Lewis acid such as 2.4.7 to trinitro-9-7 fluorenone or the like. The body has already been put into practical use.

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 carrier transport function of the photoconductor are shared by separate substances, such as amorphous selenium. A photoreceptor having a photosensitive layer consisting of a carrier generation layer formed from a thin layer and a carrier transport layer mainly containing poly-N-vinyl rubazole has already been put into practical use.

However, poly-N-vinyl Rubazole lacks flexibility, and its film is hard and brittle, and is prone to cracking and peeling. 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 the ability to form a film, they are used in combination with an appropriate binder, and by selecting the type of binder, composition ratio, etc., the physical properties or photosensitive characteristics of the film can be controlled to a certain extent. Although it is preferable because it can be controlled,
There are a limited number of organic photoconductive compounds that have high compatibility with binders. In reality, there are only a few types of binders that can be used in the structure of the photosensitive layer of a photoreceptor, particularly an electrophotographic photoreceptor.

For example, 2,5 described in U.S. Pat. No. 3,189,447.
-bis(p-diethylaminophenyl)-1.3.4-
Xadiazole has low compatibility with binders commonly used as materials for the photosensitive layer of electrophotographic photoreceptors, such as polyester and polycarbonate. If formed, oxadiazole crystals will precipitate at a temperature of 50° C. or higher, which has the disadvantage of deteriorating electrophotographic properties such as charge retention and sensitivity.

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

U.S. Patent No. 3,274.000, Special Publication No. 1974-3
No. 6428 describes different types of 7-enothiazine derivatives, but all of them have the drawbacks of low photosensitivity and low stability during repeated use.

Also, JP-A-58-65440, JP-A No. 58-198043
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 no carrier transporting substance has yet been found that has practically satisfactory characteristics for controlling electrophotographic photoreceptors.

[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.

[Means to solve the problem]

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

General formula [I] In the formula, A r ′ + A r 2+ A r 3* A
r' + A r' + A r' is substituted or unsubstituted three groups; alkyl group. aryl group,
Indicates an aralkyl group.

R represents a hydrogen atom, a halogen atom, or the following two alkyl groups or alkoxy groups which may have a substituent.

More details: Ar', Ar2, Ar3, Ar', Ar
The alkyl group of ', Ar' is methyl. Ethyl, proyl, butyl, and phenyl as an aryl group. Examples of aralkyl groups include naphthyl and benzyl. Examples include groups such as phenethyl.

Examples of halogen atoms for R include chlorine, bromine, iodine atoms, etc.
Examples of the alkyl group include methyl, ethynole, propyl, and butyl, and examples of the alkoxy group include methoxy and ethoxy groups.

Next, examples of combinations of the compounds according to the present invention will be shown below.

(Example of compound 2) Copper powder 12.0g, potassium carbonate 20.0g, 3.5.
9.0 g of 4'-tetraiodobi7enyl and 8.6 g of di7enylamine were heated at 180° C. for 24 hours with stirring. After cooling, inorganic substances were removed and extraction was performed with 300 m+2 of toluene. The organic layer was washed with water, dried with sodium sulfate, dried under reduced pressure, and recrystallized with a toluene-hexane mixed solvent to obtain 8.3 g of the desired product.
(yield 78%).

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 certain photosensitive layer 4 is provided on a conductive support 1 from 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. .

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 as described above, a photoreceptor having the most excellent electrophotographic properties can be obtained. Further, in the present invention, as shown in FIGS. 5 and 6, the carrier generating substance 7 is dispersed in N6 containing a carrier transporting substance as a main component, and a certain photosensitive layer 4 is coated on the conductive support 1. 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 after 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 7-labanthrones (5) quinacridone dyes (6) bisbenzimidazole dyes (7) induthrone dyes (8) squarerium dyes (9) cyanine dyes (lO) azulenium dyes (ll) Triphenylmethane pigments (l2) Amol 7-asilicon (l3) 7-thalocyanine pigments such as metal cap cyanine and metal-free 7-thalocyanine (14) Selenium, selenium-tellurium, selenium-arsenic (
15) CdS%Case (l6) Examples include pyrylium salt dyes and thiavirylium salt dyes, which can be used alone or in a mixture of two or more.

Since the compound used in the present invention does not have the ability to form a coating by itself, a photosensitive layer can be 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-shaped hollow 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 CP-7) Boristyrene (p-8) Polyvinyl acetate (P-9) Styrene-butadiene copolymer (
P-10) Vinylidene chloride-acrylonitrile copolymer (P-11) Vinyl chloride-vinyl acetate copolymer (P-12) Vinyl chloride-vinyl acetate-maleic anhydride copolymer (P-13) Silicone resin (P-1
4) Silicone-alkyd resin (P-15
) Phenol formaldehyde resin (P-1
6) Styrene-Alkit resin (P-17)
Poly N-vinylcarbazole (P-18)
Polyvinyl butyral (P-19) Polyvinyl formal These binder resins can be used alone or as a mixture of two or more.

Further, as the solvent for forming the carrier generation layer and the transport layer according to the present invention, N,N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, tonolene, chloroform, 1.2
-dichloroethane, 1.2-dichloropropane, 1.
1.2-trichloroethane, l. 1.1- Trichloroethane, trichlorethylene, tetrachloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, improbanol, 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:l to 500:0 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 wt, particularly preferably 30 to 150 wt, per 100 weight (wt) of the binder resin in the carrier transport layer.

The thickness of the carrier generation layer formed as described above is:
Preferably 0.01 to IOμm1, particularly preferably 0.1
~5 μm.

Further, the thickness of the carrier transport layer to be formed is preferably 5
~50 μm1, particularly preferably 5 to 30 μm.

On the other hand, when the photoreceptor of the present invention has a single-layer functionally separated structure, the weight ratio of binder:carrier generating substance:carrier transporting substance in the photosensitive layer is preferably O-100:l to 500:l to 500, and the shape or The thickness of the photosensitive layer is preferably 5 to 50 μm, 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 the binder used for the intermediate layer, protective layer, etc., those listed above for the carrier generation layer and carrier transport layer can be used, but in addition, polyamide resin, nylon resin, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, etc. Ethylene resins such as vinyl acetate-maleic anhydride copolymer and ethylene-vinyl acetate-methacrylic acid copolymer, polyvinyl alcohol, cellulose derivatives, and the like are effective.

Organic amines can be added to the photosensitive layer of the present invention for the purpose of improving the carrier generation function of the carrier generation substance. Among organic amines, it is particularly preferable to add secondary amines.

Further, the photosensitive layer may contain deterioration inhibitors such as antioxidants and light stabilizers for the purpose of improving storage stability, durability, and environmental dependence resistance. Compounds used for such purposes include, for example, chromanol derivatives such as tocopherol and their etherified or esterified compounds, polyarylalkane compounds, hydroquinone derivatives and their mono- and di-etherified compounds, benzo7enone derivatives, penzotriazole. Derivatives, thioether ter compounds, phosphonic acid esters, phosphorous acid esters, phenylenediamine derivatives, phenol compounds, hindered phenol compounds, linear amine compounds, cyclic amine compounds, hindered amine compounds, and the like are effective. Specific examples of particularly effective compounds and L't are rlRGAN
OXIOIOJ. rlRGANOX565J (.
Ciba Geigy), ``Sumilizer BHTJ,''
Hindered phenol compounds such as Sumilizer MDPJ (manufactured by Sumitomo Chemical Co., Ltd.), Sanol LS-2626J
, "Hindered amine compounds such as Sanol LS-622LDJ (manufactured by Sankyo Co., Ltd.).

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, and the like.

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, m-dinitrobenzene,
l. 3.5-trinitrobenzene, varanitrobenzonitrile, picrin chloride, quinone chlorimide, chloranil, brumanil, dichlorodicyanobarabenzoquinone, anthraquinone, dinitroanthraquinone, 2.
7-dinitrofluorenone, 2.4.7-trinitrofluorenone, 2,4.5.7-tetranitrofluorenone, 9-fluorenylidene-malonodinitrile, polynitro-9-7-fluorenylidene-malonodinitrile, viculin acid, 0-nitrobenzoic acid, p-nitrobenzoic acid, 3,
5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-
Examples include nitrosalicylic acid, 3,5-dinitosalicylic acid, heptatalic acid, mellitic acid, and other compounds with high electron affinity.

The amount of the electron-accepting substance added is carrier-generating substance:electron-accepting substance-t00 in a weight ratio of 0.01 to 200, preferably 100:0.1 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, Ol~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 later, it has excellent charging characteristics, sensitivity characteristics, and image shape 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 (LE)
It can also be widely used in application fields such as photoreceptors for printers using D) as a light source.

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

Example 1 Vinyl chloride-vinyl acetate maleic anhydride copolymer "S-LEC MF-10J (manufactured by Sekisui Chemical Co., Ltd.)
A certain thickness O. An intermediate layer of Oaμm is provided, and dibromoanthron "Monolite 1/-j de 2" is placed on top of it.
Y J (C.I. No. 59300 manufactured by 1C1) Ig was added to 30 mQ of 1,2-dichloroethane and dispersed in a ball mill, and polycarbonate "Panlite L-1250J (manufactured by Teijin Chemical Co., Ltd.) was added to the dispersion obtained. ) 1
．． 5 g was dissolved and thoroughly mixed; the coating solution was applied to a dry film thickness of 2 μm to form a carrier generation layer.

On top of that, 5g of exemplified compound (2) and polycarbonate
rz-200'' (Mitsubishi Gas Chemical) log and deterioration prevention agent rlRGANOX IOIOJ was added to the carrier transport substance at 2%, and a solution dissolved in 80ml of l,2-dichloroethane (2) was added so that the film thickness after drying was 20 μm. A photoreceptor of the present invention was prepared by coating the photoreceptor to form a carrier transport layer.

The photoreceptor obtained as described above was manufactured by Kawaguchi Electric Co., Ltd.
The following characteristics were evaluated using PA-8100. After charging at 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 became 2 Qux, and the initial surface potential VA1 was halved by the exposure amount E.
Find l/2 and t;. Furthermore, similar measurements were repeated too many times. The results are shown in Table 1. Comparative Example (1) A comparative photoreceptor was prepared in the same manner as in Example 1, except that the following compound was used as a carrier transporting substance.

Examples 2 to 7 Photoreceptors were prepared and measured in the same manner as in Example 1, except that the exemplified compounds shown in Table 2 below were used instead of exemplified compound (2).

Table 2 This comparative photoreceptor was measured in the same manner as in Example 1, and the results shown in Table 3 were obtained.

Further, in this photoreceptor, precipitates were observed in the carrier transport layer after coating.

Example 8 An intermediate layer having a thickness of 0.1 am made of polyamide resin rA-70J (manufactured by Toray Industries, Inc.) was provided on a conductive support in which aluminum was vapor-deposited on a polyester film.

A photoreceptor was prepared and measured in the same manner as in Example 8, except that the exemplified compounds shown in Table 5 below were used instead of exemplified compound (2).

1.2 g of bisazo pigment having the above structure and 2 g of polycarbonate resin "Panlite L-1250J"
The mixture was mixed with 100 m4 of diluted ethane and crushed in a sand grinder for 8 hours. This dispersion was applied onto the intermediate layer so that the thickness after drying was 0.2 μm.

A photoconductor was prepared in the same manner as in Example 1 using Exemplified Compound (2) as a carrier transporting substance and adding 2% of the deterioration inhibitor RGANOX IOIOJ to the carrier transporting substance. The same measurements as in Example 1 were carried out, and the results shown in Table 4 were obtained.

Table 4 Comparative Example (2) A comparative photoreceptor was prepared in the same manner as in Example 8 except that the following compound was used as a carrier transport substance.

Examples 9 to 14 This photoreceptor was measured in the same manner as in Example 1, and the results shown in Table 6 were obtained.

Table 6 In addition, in this photoreceptor, precipitated substances were observed in the carrier transport layer after coating.

Example 15 A 0.2 μm thick intermediate layer made of polyamide resin CM8000J (manufactured by Toray Industries, Inc.) was provided on a conductive support made of a polyester film on which aluminum was vapor-deposited.

2 g of titanyl 7 talocyanine and silicone tiNIW rKR-524 with the X-ray diffraction spectrum shown in Figure 7.
Disperse 20g of 0.15% xylene-butanol solution (manufactured by Shin-Etsu Chemical Co., Ltd.) in isoprobyl alcohol room+2 using a sand mill, and apply this dispersion on the intermediate layer to a dry thickness of 0.2 μm. I applied it to make it look like this. Then, exemplified compound (2) is added thereon as a carrier transport substance.
7 g and polycarbonate r Z-200J Log were dissolved in 80 mQ of 1,2-dichloroethane. This solution was applied so that the film thickness after drying was 20 μm to form a carrier transport layer.

This photoreceptor was strained and measured in the same manner as in Example 1, and the results shown in Table 7 were obtained.

Table 7 Example 16 A 0.2 μm thick intermediate layer made of ethylene-acetate-be-methacrylic acid copolymer resin “ELVAX 4260J (manufactured by DuPont Mitsui Chemicals) was formed on an aluminum drum.

Exemplary compound (2) I as a carrier transport substance of the present invention
A solution prepared by dissolving 1.5 g of g and polyester resin "Vylon 200" (manufactured by Toyobo Co., Ltd.) in 1,2-dichloroethane lomQ is applied onto the intermediate layer, and after drying, a film thickness of 15 μm is applied.
A carrier transport layer of m was formed. On the other hand, the X-ray diffraction spectrum shown in Figure 7 is used as a carrier-generating substance, and the titanium hydroxide cyanine Igx is used as a binder resin.
3 g, 15 mQ of monochlorobenzene as a dispersion medium, and 1
．． After dispersing 35 mR of chloroethane using a Pall mill, exemplified compound (2) was further added as a carrier transport substance at a ratio of 75% to the binder resin.

The dispersion thus obtained was placed on the carrier transport layer,
It was coated by a spray coating method to form a carrier generation layer with a thickness of 2 μm.

The thus obtained photoreceptor was evaluated in the same manner as in Example 1, except that the charging polarity was changed to positive polarity.

VA-1180 (V) E 172-0.9 (lux-sec)
Example 17 On an aluminum drum, vinyl chloride-vinyl acetate-maleic anhydride copolymer 1kr Eslec MF-IO' (
(manufactured by Sekisui Chemical Co., Ltd.) with a thickness of O. An intermediate layer of 1 μm was formed. On the other hand, after pulverizing Dipromoanthrone "Monolite Red 2Y" Ig as a carrier generating material in a pole mill, polycarbonate resin "Vanlite L-1250J" 3 g, monochlorobenzene 15 m
A solution of 35+nQ of α,1,2-dichloroethane was added to perform dispersion. To the obtained dispersion, 2 g of the carrier transport substance exemplified compound (2) of the present invention was further added, and the mixture was applied onto the intermediate layer by spray coating and dried to form a photosensitive layer with a thickness of 20 μm. Shaped.

The thus obtained photoreceptor was evaluated in the same manner as in Example 1, except that the charging polarity was changed to positive polarity.

VA=　1380　　(V) E　,,,　　　　　2.5　　　(lux●sec)

[Brief explanation of drawings]

1 to 6 are cross-sectional views of examples of the photoreceptor of the present invention. Figure 7 shows the C of titanyl phthalocyanine used in the examples.
It is an X-ray diffraction diagram for u-Ka rays. Support Carrier generation layer Carrier transport layer Photosensitive layer Intermediate layer Protective layer

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor having a layer containing a compound represented by the following general formula [I]. General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, Ar^1, Ar^2, Ar^3, Ar^4, Ar
^5, Ar^6 are substituted or unsubstituted three groups;
Indicates an alkyl group, an aryl group, and an aralkyl group. R represents a hydrogen atom, a halogen atom, or the following two alkyl groups or alkoxy groups which may have a substituent. ]