JPH01265258A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity and durability by incorporating a specified hydrazone derivative in a photosensitive layer. CONSTITUTION:The photosensitive layer 4 is formed by laminating on a conductive substrate 1 an interlayer 5 when needed, a carrier generating layer 2 containing a carrier generating material (A) and a carrier transfer layer 3 containing as a carrier transfer material one of the hydrazone derivatives represented by formula I in which R1 is H, alkyl, or aryl, and each of R2 and R3 is alkyl or aryl, and said compound (A) can be embodied by formula II and the like. The layers 2, 3 can both be formed by coating or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to a novel electrophotographic photoreceptor having a photosensitive layer containing an organic photoconductive compound as a main component.

[Prior art]

Conventionally, inorganic photoreceptors having a photosensitive layer containing an inorganic photoconductive compound such as selenium, zinc oxide, cadmium sulfide, or silicon as a main component have been widely used as electrophotographic photoreceptors. However, these were not necessarily satisfactory in terms of sensitivity, thermal stability, moisture resistance, durability, etc. For example, when selenium crystallizes, its properties as an electrophotographic photoreceptor deteriorate, making it difficult to manufacture.Also, selenium crystallizes due to heat, fingerprints, etc., and its performance as an electrophotographic photoreceptor deteriorates. In addition, cadmium sulfide and zinc oxide
There were problems with moisture resistance and durability.

In order to overcome these drawbacks of inorganic photoreceptors, research and development have been actively conducted in recent years on organic photoreceptors having photosensitive layers containing various organic photoconductive compounds as main components.

For example, Japanese Patent Publication No. 50-10496 describes an organic photoreceptor comprising a photosensitive layer containing poly-N-vinylcarbazole and 2,4,7-dolinitro-9-fluorenone. However, this photoreceptor is not necessarily satisfactory in terms of sensitivity and durability.

In order to improve these drawbacks, attempts have been made to develop a high-performance organic photoreceptor in which the carrier generation function and the carrier transport function are shared by different substances. Many studies have been conducted on such so-called functionally separated photoreceptors because each material can be selected from a wide range and a photoreceptor having arbitrary performance can be produced relatively easily.

As a result, various azo compounds have been developed and put into practical use as carrier-generating substances. On the other hand, regarding carrier transport substances, for example, JP-A Nos. 51-94829, 52-72231, 53-27033, 55-
No. 52063, No. 58-65440, No. 58-198
A wide variety of substances have been proposed, as disclosed in No. 425 and the like.

[Problem that the invention seeks to solve]

Some electrophotographic photoreceptors using carrier transport materials such as those described above exhibit relatively excellent electrophotographic performance, but their durability against light, ozone, or electrical loads is weak, and performance may deteriorate after repeated use. Since it is stable and causes deterioration, it does not fully satisfy practical requirements, and it is desired to develop a carrier transport material that has even better carrier transport function and exhibits stable performance for long-term use. was.

Furthermore, the demand for installing organic photoreceptors in electrophotographic copying machines capable of copying at higher speeds has been increasing in recent years, and the development of photoreceptors with higher sensitivity and higher durability has been desired.

The present invention has been made to solve these problems and provide a photoreceptor with extremely high sensitivity and high durability.

[Means for solving problems]

The above problem is solved by an electrophotographic photoreceptor having a photosensitive layer comprising a layer containing a hydrazone derivative represented by the following formula CI) on a conductive support.

(Formula CI), where R3 is a hydrogen atom, an alkyl group, an aryl group, preferably a hydrogen atom, an alkyl group having 1 to 8 carbon atoms,
It represents a phenyl group or a naphthyl group, and R,, R, represents an alkyl group or an aryl group, preferably an alkyl group having 1 to 8 carbon atoms, a phenyl group, or a naphthyl group. Moreover, these groups may have a substituent.

That is, in the present invention, the carrier transport ability of the compound represented by formula CI) is utilized to create a carrier transport material for a so-called functionally separated electrophotographic photoreceptor in which carrier generation and transport are performed using separate substances. By using it as a coating, it has excellent physical properties, excellent electrophotographic properties such as charge retention, sensitivity, and residual potential, and has little fatigue deterioration even after repeated use, and is resistant to heat, ozone, and light. It is possible to create an electrophotographic photoreceptor that can exhibit stable characteristics.

Further, the carrier transport substance used in the present invention can be used alone or in combination of two or more of the compounds represented by formula CI), and can also be used in combination with other carrier transport substances. good.

Specific examples of the carrier transporting substance shown by the above-mentioned formula [1] that are effective in the present invention include those having the following structural formula, but this limits the carrier transporting substance according to the present invention. It's not a thing.

The carrier transport material described above is easily synthesized by known synthesis methods. For example, reference may be made to the methods described in JP-A-57-64244 and JP-A-57-67940.

Synthesis Example (Synthesis of Exemplified Compound (1)) 4.6 g (0.02 mol) of 2-pyrenecarbaldehyde and 2.4 g (0.02 mol) of methylphenylhydrazine were dissolved in 50 ml of ethanol, and 2 mff of acetic acid was added. addition 5
The mixture was heated to reflux for an hour. The crystals precipitated by cooling were collected by filtration, washed with ethanol, and then recrystallized from a mixed solvent of ethanol methyl ketone.

Yield: 4.6 g (68.9%) It was confirmed that the target product was synthesized by observing a molecular ion peak of 334 in FD-mass spectrum.

Elemental analysis calculation values C: 86.19% H: 5.44% N
: 8.39% actual value C: 86.15% H: 5
．． 42% N: 8.43%Next, as a carrier generating substance suitable for the present invention, an azo pigment is preferable, but in general, an inorganic pigment can be used as long as it absorbs visible light to infrared light and generates a carrier. and organic pigments can be used. For example, in addition to inorganic pigments such as amorphous selenium, trigonal selenium, selenium-arsenic alloy, selenium-tellurium alloy, and cadmium sulfide, organic pigments such as those shown in the following representative examples may be used.

(1) Azo pigments such as monoazo pigments, bisazo pigments, trisazo pigments, metal complex azo pigments, etc. (2) Perylene pigments such as perylene acid anhydride, perylene acid imide, etc. (3) Anthraquinone derivatives, anthanthrone derivatives, dibenzpyrenequinone derivatives, pyranthrone derivatives,
Polycyclic quinone pigments such as violanthrone derivatives and inviolanthrone derivatives (4) Indigoid pigments such as indigo derivatives and thioindigo derivatives (5) Phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine (6) Diphenylmethane pigment, triphenylmethane pigment , carbonium pigments such as xanthine pigments and acridine pigments (7) quinone imine pigments such as azine pigments, oxazine pigments and thiazine pigments (8) methine pigments such as cyanine pigments and azomethine pigments (9) quinoline pigments (10) benzoquinone and naphthoquinone pigments (11
) Naphthalimide pigments (12) Perinone pigments such as bisbenzimidazole derivatives The carrier transport substance used in the present invention does not have the ability to form a film by itself, so a photosensitive layer is formed by combining it with various binders. .

Although any binder can be used for the carrier generation layer and the carrier transport layer, it is preferable to use a hydrophobic electrically insulating film-forming polymer. Examples of such high molecular weight polymers include, but are not limited to, the following.

(1) Polycarbonate (2) Polyester (3) Methacrylic resin (4) Acrylic resin (5) Polyvinyl chloride (6) Polyvinylidene chloride (7) Polystyrene (8) Polyvinyl acetate (9) Styrene copolymer resin (e.g. styrene -butadiene copolymer, styrene-methyl methacrylate copolymer, etc.) (10) 7') +) cy unitrile copolymer resin (
For example, vinylidene chloride-acrylonitrile copolymer, etc.) (It) Vinyl chloride-vinyl acetate copolymer (12)
Vinyl chloride-vinyl acetate-maleic anhydride copolymer (13) Silicone resin (14) Silicone-alkyd resin (15)
Phenolic resins (e.g., phenol-formaldehyde resins, cresol formaldehyde resins, etc.) (16) Styrene-alkyd resins (17) Poly-
N-vinylcarbazole (18) polyvinyl butyral (19) polyvinyl formal (20) polyhydroxystyrene These binders can be used alone or in a mixture of two or more.

As shown in FIGS. 1 and 2, the photoreceptor of the present invention comprises a carrier generating layer 2 containing a carrier-generating substance as a main component on a conductive support l, and a carrier-generating layer 2 containing a carrier-generating substance as a main component and a compound of the present invention as a main component of a carrier-transporting substance. A photosensitive layer 4 made of a laminate with a carrier transport layer 3 containing the photosensitive layer 4 is provided.

As shown in FIGS. 3 and 4, this photosensitive layer 4 may be provided via an intermediate layer 5 provided on a conductive support l.

When the photosensitive layer 4 has a two-layer structure in this manner, an electrophotographic photoreceptor having the best electrophotographic properties can be obtained. Further, in the present invention, as shown in FIGS. 5 and 6, a photosensitive layer 4 formed by dispersing a carrier generating substance 7 in the form of fine particles in a layer 6 mainly composed of the carrier transporting substance is used as a conductive support. It may be provided directly on l or via an intermediate layer S.

Furthermore, a protective layer 8 may be provided on the photosensitive layer 4 if necessary.

When the photosensitive layer 4 has a two-layer structure, which of the carrier generation layer 2 and the carrier transport layer 3 is to be the upper layer is determined by whether the charging polarity is positive or negative. That is, in the case of a negatively charged photosensitive layer, the carrier transport layer 3
It is advantageous to use the carrier transport layer 3 as the upper layer because the carrier transport material in the carrier transport layer 3 is a material that has a high transport ability for holes.

Further, a carrier generation layer 2 constituting a photosensitive layer 4 having a two-layer structure
can be formed directly on the conductive support l or the carrier transport layer 3 or after providing an intermediate layer such as an adhesive layer or a barrier layer if necessary, by the following method.

(1) Vacuum deposition method (2) Method of applying a solution of a carrier-generating substance dissolved in a suitable solvent (3) Forming the carrier-generating substance into fine particles in a dispersion medium using a ball mill, sand grinder, etc.
A method of applying a dispersion obtained by mixing and dispersing a binder.

The thickness of the carrier generation layer 2 formed in this way is
It is preferably 0.01 μm to 5 μm, more preferably 0.05 μm to 3 μm.

Further, the thickness of the carrier transport layer 3 can be changed as necessary, but it is usually preferably 5 μm to 30 μm. The composition ratio in this carrier transport layer 3 is preferably 0.8 to 10 parts by weight of the binder to 1 part by weight of the carrier transport material of the present invention, but it is preferable that the carrier-generating material in the form of fine particles is dispersed therein. When forming the photosensitive layer 4, it is preferable to use the binder in an amount of 5 parts by weight or less per 1 part by weight of the carrier-generating substance.

Further, when the carrier generation layer is configured as a dispersed layer using a binder, it is preferable to use the binder in an amount of 5 parts by weight or less per 1 part by weight of the carrier generating substance.

The layer structure of the photoreceptor of the present invention includes a laminated structure and a single layer structure as described above, and either a carrier transport layer serving as a surface layer, a carrier generation layer, a single layer photosensitive layer, or a protective layer, or a plurality of layers. The layer may contain one or more electron-accepting substances for the purpose of improving sensitivity, reducing residual potential, and reducing fatigue during repeated use.

The intermediate layer functions as an adhesive layer or a barrier layer, and in addition to the binder resin, hapolyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose, casein, etc. are used.

As the conductive support 1 used in the construction of the electrophotographic photoreceptor of the present invention, the following are mainly used, but the present invention is not limited thereto.

(1) Metal plates such as aluminum plates and stainless steel plates, and drum-shaped items.

(2) A thin layer of metal such as aluminum, palladium, or gold is provided on a support such as paper or plastic film by lamination or vapor deposition.

(3) A layer of a conductive compound such as a conductive polymer, indium oxide, or tin oxide is provided on a support such as paper or a plastic film by coating or vapor deposition.

Formation of constituent layers such as a carrier transport layer and a carrier generation layer according to the present invention includes vacuum evaporation, sputtering, CvD
A vapor deposition method such as , or a coating method such as dipping, spraying, blade, or roll method may be arbitrarily used.

The photoreceptor of the present invention has the above-mentioned structure, and has excellent charging characteristics, sensitivity characteristics, and image forming characteristics, as is clear from the examples described below. In particular, it exhibits excellent durability with little fatigue deterioration even when subjected to repeated transfer electrophotography.

〔Example〕

Examples of the present invention will be specifically described below, but the embodiments of the present invention are not limited thereby.

Example 1 A conductive support formed by vapor-depositing aluminum on a polyester film was coated with a film having a thickness of 0.5 mm and made of vinyl chloride-vinyl acetate-maleic anhydride copolymer "S-LEC MF-1O" (manufactured by Tanezu Kagaku Co., Ltd.). A 1 μm intermediate layer was provided.

On top of that, dibrom anth anthrone ``monolitere'' 2 Y J (ICHt
M) 1 part by weight and polycarbonate resin [Panlite L-
1250J (manufactured by Yondaikasei Co., Ltd.) 0.5 parts by weight and 1.2
- A carrier-generating layer was formed by mixing the mixture with 100 parts by weight of dichloroethane and dispersing it in a ball mill for 24 hours, and applying the solution to a dry film thickness of 1 μm.

Exemplary compound (1)7.
5 parts by weight and polycarbonate resin "Panlite L -
10 parts by weight of 1250J and 8 parts by weight of 1,2-dichloroethane
A carrier transport layer was formed by coating a solution dissolved in 0 parts by weight so that the film thickness after drying was 16 μm, thereby producing an electrophotographic photoreceptor of the present invention.

Regarding this electrophotographic photoreceptor, the electrostatic copying paper tester rE
Electrophotographic properties were measured using a dynamic method using PA-8100J (Kawaguchi Electric Seisakusho).

That is, the surface potential VA when the surface of the photosensitive layer of the photoreceptor is charged at a charging voltage of -6 KV for 5 seconds.

Next, the light from the tungsten lamp is applied to the surface of the photoreceptor so that the illumination intensity is 3.
．． Irradiate at 512ux, and reduce the surface potential to -6
Exposure amount required to attenuate from 00V to -100V (
Sensitivity) E::: and surface potential (residual potential) VR after irradiation with an exposure amount of 304 ux-sec were determined.

Further, similar measurements were repeated 100 times. Result is,
As shown in Table 1.

Comparative Example (1) A comparative photoreceptor (1) was prepared in the same manner as in Example 1, except that a hydrazone derivative represented by the following structural formula was used as a carrier transport substance. Example 1 and the results are shown in Table 1. As shown below.

As is clear from the results in Table 1 and above, the electrophotographic photoreceptor of the present invention of Example 1 was significantly superior to the photoreceptor of Comparative Example (1) in terms of sensitivity, residual potential characteristics, and repeated stability. It is.

Example 2-IO Exemplary compounds (2) and (4) as carrier transport substances.

(6), (8), (10), (12), (14), (1
An electrophotographic photoreceptor of the present invention was produced in the same manner as in Example 1 except that 6) and (18) were used. Measurements were performed on these electrophotographic photoreceptors in the same manner as in Example 1.

The results are shown in Table 2.

Table 2 Example 11 1 part by weight of a bisazo pigment represented by the following structural formula and a polymethyl methacrylate resin [Dianal BR-80J ( Mitsubishi Rayon Co., Ltd.)) was added to 100 parts by weight of 1,2-dichloroethane, dispersed for 4 hours using a sand grinder, and the saliva was applied so that the film thickness after drying was 0.4 μm to generate carrier. formed a layer.

Next, Exemplified Compound (3) 7.5 as a carrier transport substance
Weight parts and polycarbonate resin "Panlite K-13"
A solution obtained by dissolving 10 parts by weight of 004 (manufactured by Ryotai Kasei Co., Ltd.) in 100 parts by weight of 1,2-dichloroethane is coated so that the film thickness after drying is 15 μm to form a carrier transport layer. A photographic photoreceptor was created.

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

Comparative Example (2) A comparative photoreceptor (2) was prepared in the same manner as in Example 11 except that a hydrazone derivative represented by the following structural formula was used as a carrier transport substance. When this comparative photoreceptor was measured in the same manner as in Example 1, the results shown in Table 3 were obtained.

As is clear from the results in Table 3 and above, the electrophotographic photoreceptor of the present invention of Example 11 is significantly superior to the comparative photoreceptor in terms of sensitivity, residual potential, and repeated stability.

Example 12 A 0.1 pm-thick intermediate layer made of vinyl chloride-vinyl acetate-maleic anhydride copolymer "S-LEC MF-10J" was provided on a conductive support formed by vapor-depositing aluminum on a polyester film.

On top of that, 1 part by weight of a bisazo pigment represented by the following structural formula as a carrier-generating substance and 5 parts by weight of polycarbonate resin "Panlite K-1300J O" were added to 100 parts by weight of tetrahydrofuran and dispersed in a ball mill for 24 hours. After drying the liquid. A carrier generation layer was formed by coating the film to a thickness of 0.4 μm.

Next, an exemplified compound (5) was added thereon as a carrier transport substance.
) 7.5 parts by weight and polycarbonate resin [Panlite K
-10 parts by weight of 1300J and 1 part by weight of tetrahydrofuran
An electrophotographic photoreceptor of the present invention was prepared by applying a solution dissolved in 0.00 parts by weight so that the film thickness after drying was 17 μm.

When this electrophotographic photoreceptor was measured in the same manner as in Example 1, the results shown in Table 4 were obtained.

Example 13 An electrophotographic photoreceptor of the present invention was prepared in the same manner as in Example 12, except that a bisazo pigment represented by the following structural formula was used as a carrier-generating substance.

When this electrophotographic photoreceptor was measured in the same manner as in Example 1, the results shown in Table 4 were obtained.

Table 4 Example 14 An intermediate layer with a thickness of 0.1 μOI made of vinyl chloride-vinyl acetate-maleic anhydride copolymer "Eslenok MF-10J" was coated on a cylindrical aluminum drum with a diameter of 80 mm by a dipping method. .

On top of that, 1 part by weight of Dibrom Anthron "Monolite Red 2YJ and 1 part by weight of polycarbonate resin [Panlite L-1250J] were mixed in 100 parts by weight of 1,2-dichloroethane, and the liquid was dispersed in a ball mill for 24 hours using a dipping method. A carrier generation layer having a film thickness of 1 μm was formed by coating.

Furthermore, exemplified compound (4) is added as a carrier transport substance.
7.5 parts by weight and 10 parts by weight of polycarbonate resin rZ-2004 (manufactured by Mitsubishi Gas Chemical Co., Ltd.) represented by the following structural formula were dissolved in 80 parts by weight of 1,2-dichloroethane, and a solution was applied by the same dipping method to form a film. A carrier transport layer having a thickness of 17 μm was formed to produce an electrophotographic photoreceptor of the present invention.

This electrophotographic photoreceptor is used in an electrophotographic copying machine rU-Bix15.
When the image was copied by attaching it to a 50MRJ, a copied image was obtained that was faithful to the original, had high contrast, and had excellent gradation. Even after repeating this process 50,000 times, a copy image similar to the initial one was obtained.

Comparative Example (3) A comparative photoreceptor (3) was prepared in the same manner as in Example 14, except that a hydrazone derivative represented by the following structural formula was used as a carrier transport substance.

When images were copied using this comparative photoreceptor in the same manner as in Example 14, a good copy image was initially obtained as in Example 14, but fog started to become noticeable around 20,000 copies. However, only images with a lot of fog and reduced contrast could be obtained.

Example 15 A 0.1 μm thick intermediate layer made of vinyl chloride-vinyl acetate-maleic anhydride copolymer "S-LEC MF-1O" was provided on a conductive support made of a polyester film laminated with aluminum foil.

Next, an exemplary compound (7) was added thereon as a carrier transport substance.
) 7.5 parts by weight and polycarbonate resin "Panlite L"
-1250J dissolved in 80 parts by weight of 1,2-dichloroethane was applied to form a carrier transport layer so that the film thickness after drying was 15 μm.

Furthermore, a carrier generating substance 1 represented by the following structural formula is added thereto.
Exemplary compound (7) as part by weight and carrier transport substance
1.5 parts by weight, polycarbonate resin "Panlite L"
-1250J and 100 parts by weight of 1°2-dichloroethane were dispersed in a ball mill for 24 hours to form a carrier generation layer having a thickness of 3 μm after drying. Created.

This electrophotographic photoreceptor was measured in the same manner as in Example 1, except that the charging voltage was changed to +6 kV, and the results shown in Table 5 were obtained.

Comparative Example (4) A comparative photoreceptor was prepared in the same manner as in Example 15, except that a hydrazone derivative represented by the following structural formula was used as a carrier transport substance.

When this comparative photoreceptor was measured in the same manner as in Example 15, the results shown in Table 5 were obtained. -Hereinafter, margin edge+, / As is clear from the results in Table 5 and above, the electrophotographic photoreceptor of the present invention has extremely superior characteristics in terms of sensitivity and repetition stability compared to the comparative photoreceptor.

Example 16 A 0.1 μm thick intermediate layer made of vinyl chloride-vinyl acetate-maleic anhydride copolymer "S-LEC MF-10J" was provided on a polyester film on which aluminum was vapor-deposited.

On top of that, 1 part by weight of a bisazo pigment represented by the following structural formula as a carrier transport substance and 5 parts by weight of a polycarbonate resin [Panlite L-1250J O, 1.2-
A carrier generation layer was formed by applying a solution obtained by adding 100 parts by weight of dichloroethane and dispersing it in a ball mill for 24 hours so that the film thickness after drying was 0.3 μm.

Furthermore, exemplified compound (9) is added as a carrier transport substance.
7.5 parts by weight and polycarbonate resin "Panlite K"
-1300J dissolved in 100 parts by weight of 1,2-dichloroethane was coated to form a carrier transport layer such that the film thickness after drying was 16 μm, thereby producing an electrophotographic photoreceptor of the present invention. .

This electrophotographic photoreceptor was prepared in the same manner as in Example 1. (manufactured by Toyobo Co., Ltd.) 0.5
parts by weight in 100 parts by weight of 1,2-dichloroethane and dispersed in a ball mill for 24 hours, and then coated to a thickness of 0.5 μm.
A carrier generation layer of m was formed.

Furthermore, an exemplary compound (11) is added thereon as a carrier transport substance.
) and 10 parts by weight of the polycarbonate resin "Panlite K-1300J" dissolved in 100 parts by weight of 1,2-dichloroethane was coated to form a carrier transport layer with a thickness of 15 μm. A photoreceptor was created.

When this electrophotographic photoreceptor was measured in the same manner as in Example 1, the results shown in Table 7 were obtained.

Comparative Example (5) Example 1 except that 4.0 parts by weight of a hydrazone derivative (A) represented by the following structural formula was used as a carrier transport substance.
A comparison photoreceptor (5) was prepared in the same manner as in Example 7.

When this comparative photoreceptor was measured in the same manner as in the examples, the results shown in Table 7 were obtained.

As is clear from the results in Table 7 and above, the electrophotographic photoreceptor of the present invention was significantly superior in sensitivity, residual potential characteristics, and repeated stability compared to the comparative photoreceptor.

[Brief explanation of the drawing]

1 to 6 are sectional views showing examples of the mechanical structure of the photoreceptor of the present invention, respectively. 1... Conductive support 2... Carrier generation layer 3... Carrier transport layer 4... Photosensitive layer 5... Intermediate layer 6 ...Layer 7 containing a carrier transport substance...
...Carrier generating substance 8...Protective layer

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor comprising a photosensitive layer containing at least one hydrazone derivative represented by the following general formula [I] on a conductive support. General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc. It may have a group. ]