JP3111267B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic photosensitive member, and more particularly, to an electrophotographic photosensitive member having a photosensitive layer containing a carrier generating substance and a carrier transporting substance.

[0002]

2. Description of the Related Art Conventionally, selenium,
Those having a photosensitive layer containing an inorganic photoconductor such as zinc oxide, cadmium sulfide, or silicon as a main component have been widely known. However, these are not always satisfactory in characteristics such as thermal stability and durability, and also have problems in production and handling.

On the other hand, a photoreceptor having a photosensitive layer containing an organic photoconductive compound as a main component is relatively easy to manufacture, inexpensive, easy to handle, and generally used as a selenium photoreceptor. It has many advantages, such as better thermal stability, and as such an organic photoconductive compound, poly-N-vinylcarbazole is the most well-known, and this is 2,4,7- A photoreceptor having a photosensitive layer mainly composed of a charge transfer complex formed from a Lewis acid such as trinitro-9-fluorenone has already been put to practical use.

On the other hand, there is known a photoreceptor having a function-separated type photosensitive layer of a laminated type or a single layer type in which a carrier generating function and a carrier transporting function of a photoconductor are respectively assigned to different substances. A photoreceptor having a photosensitive layer including a carrier generation layer composed of a thin selenium layer and a carrier transport layer containing poly-N-vinylcarbazole as a main component has already been put to practical use.

[0005] However, poly-N-vinylcarbazole is
Lack of flexibility, the film is hard and brittle, easily cracks and peeling, and the photoreceptor using this is inferior in durability. In practice, the residual potential increases, and the residual potential accumulates with repeated use, so that the fog gradually increases and the copied image is damaged.

In addition, since low molecular organic photoconductive compounds generally do not have a film-forming ability, they are used in combination with an appropriate binder, and the physical properties or photosensitive characteristics of the film can be improved by selecting the type and composition ratio of the binder. Although it is preferable in that it can be controlled to some extent, types of organic photoconductive compounds having high compatibility with the binder are limited. Photoconductor in reality,
In particular, there are few types of binders that can be used for forming the photosensitive layer of the electrophotographic photosensitive member.

For example, US Pat. No. 3,189,447 describes 2,5
-Bis (p-diethylaminophenyl) -1,3,4-oxadiazole has low compatibility with binders commonly used as materials for the photosensitive layer of the electrophotographic photoreceptor, such as polyester and polycarbonate, and has poor electrophotographic properties. When the photosensitive layer is formed by mixing at a ratio required for conditioning, crystals of oxadiazole come to be precipitated at a temperature of 50 ° C. or more, and have a disadvantage that electrophotographic properties such as charge holding power and sensitivity are reduced. .

On the other hand, the diarylalkane derivative described in US Pat. No. 3,820,989 has little compatibility problem with a binder, but has low stability to light, and is used for repetitive transfer type electrophotography in which charging and exposure are repeated. When applied to the photosensitive layer of the photoreceptor, the sensitivity of the photosensitive layer gradually decreases.

US Patent No. 3,274,000, JP-B-47-3642
No. 8 describes different types of phenothiazine derivatives, but all have the disadvantages of low photosensitivity and low stability upon repeated use.

The stilbene compounds described in JP-A-58-65440 and JP-A-58-198043 have relatively good charge holding power and sensitivity, but they are not satisfactory in durability when used repeatedly. Absent. These compounds also have a problem in sensitivity at low potential.

Further, as a carrier transporting substance,
Nos. 549, 63-292141 and JP-A-2-210451 propose hydrazone compounds.

As a matter of fact, a carrier transporting material having practically satisfactory characteristics for producing an electrophotographic photosensitive member has not been found yet.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photosensitive member having high sensitivity.

Another object of the present invention is to provide an electrophotographic photosensitive member having high sensitivity and low residual potential.

Another object of the present invention is to provide an electrophotographic photosensitive member having high repetition stability.

[0016]

Means for Solving the Problems As a result of intensive studies for the above-mentioned object, at least one of the hydrazone compounds represented by the general formula [I] shown in the above-mentioned "Chemical formula 1" and having a binding element defined. Has been found to have excellent utility.

Next, specific examples of the compound represented by the general formula [I] will be given.

[0018]

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[0019]

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An example of the synthesis of the exemplified compound will be described below with reference to the reaction formula (1).

Method for synthesizing compound example (A6)

[0022]

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As shown in the reaction formula (1), 20 g (0.042 mol) of (1) and 4.7 g (0.042 mol) of (2) were placed in a 200 ml four-necked flask.
mol) was dispersed in 100 ml of alcohol, and 0.5 g of acetic acid was added. The mixture was stirred with heating, boiled and reacted for 3 hours. After allowing to cool, the crystals are collected by filtration and purified by column chromatography to obtain the desired product (3).
Was obtained (yield = 55%).

The results of the elemental analysis are as follows.

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

Although various structures are known for the structure of the electrophotographic photosensitive member, the electrophotographic photosensitive member of the present invention can take any of these forms.

Normally, the configuration is as shown in FIGS. 1 (1) to 1 (6). 1 (1) and 2 (2), a carrier generating layer 2 mainly composed of a carrier generating substance is provided on a conductive support 1.
And a photosensitive layer 4 composed of a laminate of a carrier transport layer 3 containing a carrier transport material as a main component.

The photosensitive layer 4 may be provided via an intermediate layer 5 provided on a conductive support, as shown in FIGS. Thus, when the photosensitive layer 4 has a two-layer structure, a photosensitive member having the best electrophotographic characteristics can be obtained.
In the present invention, as shown in FIGS. 5 and 6, the photosensitive layer 4 formed by dispersing the carrier generating substance 7 in a layer 6 containing a carrier transporting substance as a main component is used as a conductive support. 1 may be provided directly or via an intermediate layer 5. In the present invention, a protective layer 8 may be provided as the outermost layer as shown in FIG.

The following are examples of the carrier generating substance used in the carrier generating layer of the photosensitive layer according to the present invention.

(1) Azo dyes such as monoazo dyes, disazo dyes and trisazo dyes (2) Perylene dyes such as perylene anhydride and perylene imide (3) Indigo dyes such as indigo and thioindigo (4) Anthra Polycyclic quinones such as quinone, pyrenequinone and flavanthrone (5) quinacridone dye (6) bisbenzimidazole dye (7) indathrone dye (8) squarylium dye (9) cyanine dye (10) Azulenium dyes (11) Triphenylmethane dyes (12) Amorphous silicon (13) Phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine (14) Selenium, selenium-tellurium, selenium-arsenic (15) CdS, CdSe (16) ) Pyrylium salt dyes, thiapyrylium salt dyes and the like, It can also be used as a German or in combination of two or more.

Since the compound of the present invention has no coating forming ability by itself, a photosensitive layer is formed by combining various binders.

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

(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-8) Polyvinyl acetate (P-9) Styrene-butadiene copolymer (P-10) Vinylidene chloride-acrylonitrile copolymer (P-11) Vinyl chloride-vinyl acetate copolymer (P-12) Chloride Vinyl-vinyl acetate-maleic anhydride copolymer (P-13) Silicone resin (P-14) Silicone-alkyd resin (P-15) Phenol formaldehyde resin (P-16) Styrene-alkyd resin (P-17) Poly -N-vinyl carbazole (P-18) polyvinyl butyral (P-19) polyvinyl formal These binder resins may be used alone or Can be used as a mixture of two or more.

The solvent for forming the carrier generating layer and the transport layer according to the present invention includes N, N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, 1,2-dichloroethane. , 1,2-dichloropropane, 1,1,
2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane, dichloromethane,
Tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve and the like,
They can be used in combination.

When the photoreceptor of the present invention is a laminated photoreceptor, the weight ratio of the binder and the carrier transporting substance to the carrier generating substance in the carrier generating layer is 0.2 to 5 parts by weight when the carrier generating substance is 1 part by weight. And 0 to 1 part by weight of a carrier transporting substance.

Further, the carrier generating layer may be formed of the carrier generating substance alone.

If the content of the carrier-generating substance is less than 15% (by weight) in the carrier-generating layer, the photosensitivity is low and the residual potential is increased, and if it is more than this, the dark decay and the receiving potential are reduced.

The thickness of the carrier generating layer formed as described above is preferably 0.01 to 10 μm, particularly preferably
0.1 to 5 μm.

The carrier transporting material 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 transporting layer.

The thickness of the carrier transport layer to be formed is
It is preferably from 5 to 50 μm, particularly preferably from 10 to 35 μm.

On the other hand, when the photoreceptor of the present invention has a single-layer structure,
The weight ratio of the binder and the carrier transporting substance to the carrier generating substance is preferably 0.2 to 5 parts by weight of the binder and 1 to 5 parts by weight of the carrier transporting substance when the carrier generating substance is 1 part by weight. The thickness is preferably from 5 to 50 μm, particularly preferably from 5 to 30 μm.

Examples of the conductive support used in the electrophotographic photoreceptor of the present invention include a metal plate, a metal drum or a conductive polymer containing an alloy, a conductive compound such as indium oxide, and aluminum or palladium containing an alloy. Paper, plastic film, etc., which are made conductive by applying, depositing or laminating a thin metal layer such as gold.

As the binder used for the intermediate layer, the protective layer and the like, those mentioned above for the carrier generating layer and the carrier transporting layer can be used. In addition, polyamide resin, nylon resin, ethylene-vinyl acetate, etc. Polymer, ethylene-vinyl acetate-maleic anhydride copolymer,
Ethylene resins such as 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 generating function of the carrier generating substance. Among the organic amines, it is particularly preferable to add a secondary amine.

Further, in the above-mentioned photosensitive layer, storage stability, durability,
For the purpose of improving environmental resistance, a deterioration preventing agent such as an antioxidant and a light stabilizer can be contained. Compounds used for such purposes include, for example, chromanol derivatives such as tocopherol and etherified or esterified compounds thereof, polyarylalkane compounds, hydroquinone derivatives and mono- and dietherified compounds thereof, benzophenone derivatives, benzotriazole derivatives, thioethers Compounds, phosphonates, phosphites, phenylenediamine derivatives, phenolic compounds, hindered phenolic compounds, linear amine compounds,
Cyclic amine compounds, hindered amine compounds, and the like are effective. Specific examples of particularly effective compounds include Ao-1
Hindered phenol compounds such as "IRGANOX1010", Ao-2 "IRGANOX565" (manufactured by Ciba-Geigy), Ao-3 "Sumilyzer BHT", Ao-4 "Sumilyzer MDP" (manufactured by Sumitomo Chemical Co., Ltd.), and Ao-5 "Sanol LS-2626", Ao-
6 "Sanol LS-622LD" (manufactured by Sankyo) and the like. The weight ratio of these compounds to the carrier transporting material is 1: 0.001-0.1, preferably 1: 1.
0.05 to 0.1.

In the present invention, one or two or more electron accepting substances can be contained in the carrier generating layer for the purpose of improving sensitivity, reducing residual potential, or reducing fatigue during repeated use.

Examples of the electron-accepting substance which can be used here include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, and 3-nitrophthalic anhydride. Acid, 4-nitrophthalic anhydride, pyromellitic anhydride,
Merritic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene, 1,3,5-trinitrobenzene, paranitrobenzonitrile, piclink chloride, quinone chlorimide, chloranil, bulmanyl, di Chlordicyanoparabenzoquinone, anthraquinone, dinitroanthraquinone, 2,7-dinitrofluorenone, 2,4,7-trinitrofluorenone,
2,4,5,7-tetranitrofluorenone, 9-fluorenylidenemalonodinitrile, polynitro-9-fluorenylidene-
Malonodinitrile, picric acid, o-nitrobenzoic acid, p-
Nitrobenzoic acid, 3,5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,5-dinitrosalicylic acid, phthalic acid, melitic acid, etc.
Nos. 2,214,866 and 2-135362, and U.S. Pat. No. 455,659.

The amount of the electron-accepting substance to be added is carrier-generating substance: electron-accepting substance = 100: 0.01 to 200, preferably 100: 0.1 to 100 by weight ratio.

The electron accepting substance may be added to the carrier transport layer. The amount of the electron-accepting substance added to the layer is carrier transporting substance: electron-accepting substance = 100: 0.01 to 1 by weight ratio.
00, preferably 100: 0.1 to 50.

The photoreceptor of the present invention may further contain, if necessary, an ultraviolet absorber for the purpose of protecting the photosensitive layer, and may contain a dye for correcting color sensitivity.

The electrophotographic photoreceptor of the present invention has the above-mentioned structure and, as will be apparent from Examples described later, has excellent charging characteristics, sensitivity characteristics, and image forming characteristics, and particularly when used repeatedly. Also, it has little fatigue deterioration and excellent durability.

Further, the electrophotographic photosensitive member of the present invention can be widely used in application fields such as a photosensitive member of a printer using a laser, a cathode ray tube (CRT), and a light emitting diode (LED) as a light source, in addition to an electrophotographic copying machine. .

[0064]

EXAMPLES The present invention will be described below in more detail with reference to Examples, but it should not be construed that the present invention is limited thereto.

Note that the examples are group A of examples according to the general formula [I].

§Example group A Example A1 A vinyl chloride-vinyl acetate-maleic anhydride copolymer “Eslec MF-10” (manufactured by Sekisui Chemical Co., Ltd.) on a conductive support obtained by depositing aluminum on a polyester film. An intermediate layer having a thickness of 0.04 μm is provided, and a dibromoanthranthrone “Monolite Red 2Y” (C.I.N.
o.59300 ICI) (1 g) was added to 30 ml of 1,2-dichloroethane and dispersed by a ball mill. 1.5 g of polycarbonate "Panlite L-1250" (Teijin Chemical Co., Ltd.) was added to the resulting dispersion.
Is dissolved and the coating solution after mixing is dried to a thickness of 2 μm.
To form a carrier generation layer.

Further, 5 g of the exemplified compound (A2), 10 g of polycarbonate “Z-200” (Mitsubishi Gas Chemical) and Table 1
A solution prepared by dissolving 0.5 g of a deterioration inhibitor shown in (1) in 80 ml of 1,2-dichloroethane was applied so that the film thickness after drying became 20 μm to form a carrier transport layer, thereby preparing a photoreceptor of the present invention.

The photoconductor obtained as described above was evaluated for the following characteristics using EPA-8100 manufactured by Kawaguchi Electric Co., Ltd. After charging for 5 seconds at a charged voltage of -6 KV, the device was left in the dark for 5 seconds, and then irradiated with a halogen lamp so that the illuminance on the surface of the photoreceptor became 2 lux.
1/2 was determined. Further, the residual potential Vr after exposure at an exposure amount of 30 lux · sec was determined.

Examples A2 to A6 Photoreceptors were prepared and measured in the same manner as in Example 1 except that the exemplified compounds shown in Table 1 were used instead of the exemplified compound (A2).

Comparative Example A (1) Compound T represented by the following Chemical Formula 11 as a carrier transporting substance
A comparative photoconductor was prepared in the same manner as in Example A1, except that No.1 was used.

The comparative photoreceptor was measured in the same manner as in Example A1.

Table 1 summarizes the results of Examples A1 to A6 and Comparative Example A (1).

Example A7 A polyamide resin "A-70" (manufactured by Toray Industries, Inc.) was placed on a conductive support obtained by evaporating aluminum on a polyester film.
An intermediate layer having a thickness of 0.1 μm was formed.

The bisazo pigment CG70 shown in the following "Chemical Formula 11"
5; 2g and polycarbonate resin "Panlite L-1250"
2 g was mixed with 100 ml of 1,2-dichloroethane, and dispersed in a sand grinder for 8 hours. This dispersion was applied onto the intermediate layer such that the thickness after drying was 0.2 μm.

The compound (A) as a carrier transporting substance
Using 4), a photoreceptor was prepared in the same manner as in Example 1, except that the deterioration inhibitor shown in Table 1 was added to the carrier transporting substance in an amount of 1.5 wt%. This photoreceptor was also measured in the same manner as in Example A1.

Examples A8 to A12 Photoreceptors were prepared and measured in the same manner as in Example A7 except that the exemplified compounds shown in Table 1 were used instead of the exemplified compound (A4).

Comparative Example A (2) A comparative photoreceptor was prepared in the same manner as in Example A7 except that the compound T2 represented by Chemical Formula 11 was used as a carrier transporting substance.

The photosensitive member was measured in the same manner as in Example A1.

Table 1 shows the results of Examples A7 to A12 and Comparative Example A (2).

Example A13 A 0.2 μm thick intermediate layer made of polyamide resin “CM8000” (manufactured by Toray Industries, Inc.) was provided on a conductive support obtained by evaporating aluminum on a polyester film.

2 g of titanyl phthalocyanine having an X-ray diffraction spectrum shown in FIG. 2 and a silicone resin “KR-524”
0,15% xylene-butanol solution "(Shin-Etsu Chemical Co., Ltd.)
Was dispersed in 100 ml of isopropyl alcohol using a sand mill, and this dispersion was applied on the intermediate layer so that the thickness after drying was 0.2 μm. Next, 7 g of the exemplary compound (A19) as a carrier transporting material, 10 g of polycarbonate "Z-200", and 0.5 g of a deterioration inhibitor shown in Table 1 thereon
Was dissolved in 80 ml of 1,2-dichloroethane. The film thickness after drying
This solution was applied to a thickness of 20 μm to form a carrier transport layer.

This photoreceptor was measured in the same manner as in Example A1.

Example A14 An intermediate layer having a thickness of 0.2 μm made of an ethylene-vinyl acetate-methacrylic acid copolymer resin “ELVACS 4260” (manufactured by Du Pont-Mitsui Chemicals) was formed on an aluminum drum.

As the carrier transporting material of the present invention, 1 g of the exemplified compound (A21) and the polyester resin “Vylon 200”
A solution prepared by dissolving 1.5 g (manufactured by Toyobo Co., Ltd.) in 10 ml of 1,2-dichloroethane is applied on the intermediate layer, dried, and then dried to a thickness of 15 μm.
A carrier transport layer was formed. On the other hand, 1 g of titanyl phthalocyanine having an X-ray diffraction spectrum shown in FIG. 2 as a carrier-generating substance, 3 g of polycarbonate "Panlite L-1250" (manufactured by Teijin Chemicals Ltd.) as a binder resin, 15 ml of monochlorobenzene as a dispersion medium, and 1,2 -Dichloroethane
After dispersing 35 ml using a ball mill, the exemplary compound (A21) was further added as a carrier transporting substance so as to be 75% by weight with respect to the binder resin. The dispersion thus obtained was applied on the carrier transporting layer by a spray coating method to form a carrier generating layer having a thickness of 2 μm.

The photoreceptor thus obtained was evaluated in the same manner as in Example A1 except that the charging polarity was set to a positive polarity.

Example A15 An interlayer having a thickness of 0.15 μm made of a vinyl chloride-vinyl acetate-maleic anhydride copolymer “ESREC MF-10” (manufactured by Sekisui Chemical Co., Ltd.) was formed on an aluminum drum.
On the other hand, 1 g of dibromoanthuanthrone “Monolite Red 2Y” as a carrier-generating substance was pulverized in a ball mill, and then polycarbonate resin “PANLITE L-125” was used.
0 ”3g, monochlorobenzene 15g, 1,2-dichloroethane
Dispersion was performed by adding 35 g of the liquid. The dispersion obtained was further added with the compound (A24) of the exemplary carrier transport material of the present invention.
g and 0.1 g of a deterioration inhibitor shown in Table 1 were added to the above intermediate layer by a spray coating method, followed by drying.
A photosensitive layer having a thickness of μm was formed.

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

Table 1 shows the results of Examples A13, A14 and A15.

Example A16 One part of the carrier-generating substance BIPP shown in Chemical Formula 11 and 50 parts of methyl ethyl ketone as a dispersion medium were dispersed using a sand mill, and the resulting dispersion was applied to a polyester base on which aluminum had been deposited by using a wire bar. A carrier generation layer having a thickness of 0.3 μm was formed. Next, the exemplary compound (A1
1) 1 part and polycarbonate resin "Panlite K-1300"
1.4 parts (manufactured by Teijin Chemicals Ltd.) and a small amount of silicone oil "KF-54" (manufactured by Shin-Etsu Chemical Co., Ltd.)
A solution prepared by dissolving 5 parts in 10 parts of 1,2-dichloroethane was applied using a blade coater and dried to form a carrier transport layer having a thickness of 22 μm.

Examples A17 to A21 Photoconductors of the present invention were prepared in the same manner as in Example A1, except that the exemplified compound (A11) in Example A16 was replaced with the exemplified compounds shown in Table 1.

Comparative Example A (3) A comparative photoconductor was prepared in the same manner as in Example A16, except that the exemplified compound (A11) in Example A16 was replaced with the compound T3 shown in Chemical Formula 11.

The photoreceptor thus obtained was measured in the same manner as in Example A1.

Table 1 shows the results of Examples A16 to A21 and Comparative Example A (3).

[0094]

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[0095]

[Table 1]

[0096]

[0097]

[0098]

The electrophotographic photoreceptor of the present invention has excellent chargeability, high sensitivity, surface potential even when used repeatedly,
Stable performance is obtained with little degradation of sensitivity.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a configuration example of a photoconductor of the present invention.

FIG. 2 is an X-ray diffraction spectrum of titanyl phthalocyanine used in Examples 13 and 14.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support 2 Carrier generation layer 3 Carrier transport layer 4 Photosensitive layer 5 Intermediate layer 6 Layer containing carrier transport material 7 Carrier generation material 8 Protective layer

Claims (1)

(57) [Claims] 1. An electrophotographic photoreceptor having a layer containing a hydrazone compound represented by the general formula [I]. Embedded image [In the general formula [I], R ₁ , R _2, R ₆ , and R ₇ represent an alkyl group, an aralkyl group, or an aryl group which may have a substituent, and R ₃ , R _4, and R ₅ represent a hydrogen atom indicates an optionally substituted alkyl group, an aralkyl group or an aryl group, a _r1 is an arylene group which may have a substituent. ]