JPS63235945A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the high sensitivity and durability of the titled body by providing with a photosensitive layer contg. a specified compd. on an electrically conductive supporting body. CONSTITUTION:The photosensitive layer 4 contg. the compd. shown by formula I is provided on the conductive supporting body 1. In formula I, R1 is hydrogen or halogen atom. or a substd. or an unsubstd. alkyl group or a substd. or an unsubstd. alkoxy group, R2 is hydrogen atom. or a substd. or an unsubstd. alkyl or a substd. or an unsubstd. aryl group, R3 and R4 are each a substd. or an unsubstd. aryl group, Ar is a substd. or an unsubstd. phenylene group or a substd. or an unsubstd. naphthylene group, (n) is an integer of 0, 1 or 2. Thus, titled body having the excellent film forming property and the excellent electrophotographic characteristics such as the electric charge holding power, the sensitivity and the residual electrification, etc., and the stable characteristics, even in case of repeated use, is obtd.

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) As conventional electrophotographic photoreceptors, inorganic photoreceptors having a photosensitive layer mainly composed of an inorganic photoconductive compound such as selenium, zinc oxide, cadmium sulfide, silicon, etc. have been widely used. 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. . Additionally, cadmium sulfide and zinc oxide have 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-olenon. However, this photoreceptor is not necessarily satisfactory in sensitivity and durability. In order to improve these drawbacks, attempts have been made to develop organic photoreceptors with higher performance by assigning the carrier generation function and the carrier transport function to 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.

(Problems to be Solved by the Invention) Some electrophotographic photoreceptors using carrier transport materials as described above exhibit relatively excellent electrophotographic performance, but their durability against light, ion, or electrical loads is limited. However, it does not fully satisfy practical requirements because it has weak properties and causes instability and deterioration in performance when used repeatedly.However, it has excellent carrier transport performance and stable performance for long-term use It has been desired to develop a carrier transport material that exhibits the following. Furthermore, the demand for mounting an organic photoreceptor in an electrophotographic photoreceptor capable of copying at higher speeds has been increasing in recent years, and there has been a desire to develop a photoreceptor with higher sensitivity and higher durability.

The present invention has been carried out in order to solve these problems and provide a photoreceptor with extremely high sensitivity and high durability.

(Means for solving the problem) The above problem can be solved by using an electrophotographic photoreceptor having a photosensitive layer including a layer containing a compound represented by the following general formula (1) on a conductive support. Resolved.

General formula (11) In the formula, R1 represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkoxy group, preferably a hydrogen atom, a halogen atom, or a carbon atom number of 1 to 4.
substituted or unsubstituted alkyl group, number of carbon atoms 1 to 4
represents substituted or unsubstituted alkoxy groups.

R7 represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted phenyl group, or naphthyl. represents a group.

R3, R, may be the same or different and represent a substituted or unsubstituted aryl group, preferably substituted.

Represents an unsubstituted phenyl group, a substituted or unsubstituted 7-tyl group.

11 represents an integer of 0, 1 or 2.

That is, in the present invention, only the carrier transport performance of the compound represented by the general formula CI) is utilized, and carrier transport is performed in a so-called functionally separated electrophotographic photoreceptor in which carrier generation and transport are performed using separate substances. By using it as a material, it has excellent film properties, excellent electrophotographic properties such as charge retention, sensitivity, and residual potential, and has little fatigue deterioration even when used repeatedly, and is stable against heat and light. It is possible to create an electrophotographic photoreceptor that can exhibit these 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 the general formula [1], and can also be used in combination with other photoconductive substances. May be used.

Specific examples of the carrier transporting substance useful in the present invention represented by the general formula CI) include those having the following structural formula, but the carrier transporting substance according to the present invention is not limited thereto.

, -ノ Exemplary compound (13) C1l.

(15) To C11l--1- The carrier transport substance described above is easily synthesized by a known synthesis method. For example, reference may be made to the method described in JP-A-58-198425.

Synthesis Example (Synthesis of Exemplified Compound (1)) The above compound L 30.2FI (0.1 mol) and the compound?
28.7 g (0.1 mol) were dissolved in N,N-dimethylformamide 30 (lye) and sodium methoxide t
After adding oy and reacting at room temperature for 1 hour, the mixture was heated under reflux for 10 hours to react. After cooling, it was poured into methanol 11 to precipitate crystals. The crystals were collected by filtration, washed with methanol, and then recrystallized twice from a mixed solvent of toluene and ethanol.

Yield: 21.5 g 49.4% A molecular ion peak of 435 was confirmed by FD spectrum, which confirmed that the target product 3 was obtained.

Elemental analysis value calculation value C33H25NC:90.99%+(:5.8
0% N: 3.21% Actual value C: 90.92% H: 5.85% N: 3.05% Since the carrier transport substance used in the present invention does not have the ability to form a film by itself, various results may occur. A photosensitive layer is formed in combination with an adhesive.

Any binder can be used as the binder for the carrier transport layer, but it is preferable to use a film-forming polymer that is hydrophobic, has a high dielectric constant, and is electrically insulating. 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) Acrylonitrile copolymer resin (e.g. vinylidene chloride-acrylonitrile copolymer, etc.) (11) Vinyl chloride-vinyl acetate copolymer (12)
Vinyl mide-vinyl acetate-maleic anhydride copolymer (13) Silicone resin (14) Silicone-alkyd resin (15) Phenol resin (e.g. phenol-formaldehyde resin, cresol formaldehyde resin, etc.) (16) Styrene-alkyd resin (17) ) Poly-N-vinylcarbazole (18) Polyvinyl butyral (19) Polyvinyl formal (20) Polyhydroxystyrene These binders can be used alone or as 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 the carrier generating substance of the present invention as a main component and a carrier transporting material containing the benzidine compound of the present invention on a conductive support 1. A photosensitive layer 4 consisting of a laminate with a carrier transport layer 3 containing as a main component is provided. As shown in FIGS. 3 and 4, this photosensitive layer 4 may be provided on the conductive support 1 via an intermediate layer 5. 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 fine particle carrier generating substance 7 in a layer 6 mainly composed of the carrier transporting substance is used as a conductive support. It may be provided directly on 1 or via an intermediate layer 5. Furthermore, a protective layer 8 may be provided on the photosensitive layer 4 if necessary.

Here, when the photosensitive layer N4 has two MWI compositions, which of the carrier generation layer 2 and the carrier transport layer 3 should be the upper layer is determined depending on whether the charging polarity is positive or negative. In other words, when forming a negatively charged photosensitive layer, it is advantageous to use the carrier transport layer N3 as an upper layer, and this is because the carrier transport material in the carrier transport layer 3 is a material that has a high transport ability for holes. It is from.

Further, the carrier generation layer 2 constituting the photosensitive layer 4 having a two-layer structure can be formed directly on the conductive support 1 or the carrier transport N3, or by providing an adhesive layer or a barrier layer as necessary, and then applying the following method. can be formed.

(1) Vacuum evaporation method (2) The carrier-generating substance is made into fine particles in a dispersion medium by ball milling, sand grinding, etc.
A method of applying a dispersion obtained by mixing and dispersing a binder.

As the binder used to form the carrier generation layer, any binder can be selected from among the binders used in the carrier transport layer, but it is particularly preferable to use polycarbonate, which gives preferable results.

The thickness of the carrier generation layer 2 formed in this way is 0.
．． The amount is preferably from 0.01 μl to 5 μl, and more preferably from 0.05 μl to 3 μl. Further, the thickness of the carrier transport layer 3 can be changed as necessary, but it is usually preferably 5 μl to 30 μl. 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. When forming 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.

The layer structure of the photoreceptor of the present invention includes a laminated structure and a single layer structure as described above, and one or more of a carrier transport layer serving as a surface layer, a carrier generation layer, a single N photosensitive layer, or a protective layer. 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.

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

Structure 1 of the electrophotographic photoreceptor of the present invention As the conductive support 1 used, the following are mainly used.
These are not intended to be limiting.

(1) Metal plates such as aluminum plates and stainless steel plates,
(2) A thin layer of metal such as aluminum, palladium, gold, etc. is provided on a support such as paper or a plastic film by lamination or vapor deposition. (3) A drum-shaped one on a support such as paper or a plastic film. A layer of a conductive compound such as a conductive polymer, indium oxide, or tin oxide is formed by coating or vapor deposition.For the formation of dead layers such as a carrier transport layer and a carrier generation layer according to the present invention, vacuum vapor deposition, sputtering, CV
Vapor phase deposition method such as D, or dipping, spraying,
Application methods such as blade and roll methods are optionally used.

The photoreceptor of the present invention has the above-described structure and has excellent charging characteristics, sensitivity characteristics, and image forming characteristics, as is clear from the examples described below.

In particular, even when subjected to repeated transfer electrophotography, fatigue deterioration is small and durability is excellent.

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

Example 1 A 0-thick film made of vinyl chloride-vinyl acetate-maleic anhydride copolymer [S-LEC MP-1] manufactured by H1'l Suikagaku Co., Ltd.) was placed on a conductive support made by vapor-depositing aluminum on a polyester film. .1μ shoulder intermediate layer was provided.

On top of that, 0.5 weight of Nobromoanthrone [Monolite Red 2YJ (ICI Co., Ltd., 1 part by weight and polycarbonate) resin ``Panlite L-1250J (manufactured by Ondai Kasei Co., Ltd.) expressed by the following structural formula is added. A carrier-generating layer was formed by mixing 100 parts by weight of 1,2-nochloroethane and 24 parts by weight, dispersing the mixture in a ball mill for 24 hours, and applying the liquid to a thickness of 1 μm after drying.

Furthermore, exemplified compound (1) is added as a carrier transport substance.
, 7.5 parts by weight of polycarbonate) fj (fat [10 parts by weight of Panlite L-1250J] dissolved in 100 parts by weight of 1,2-dichloroethane was applied to a film thickness of 15 μm after drying. A carrier transport layer was formed to produce an electrophotographic photoreceptor of the present invention.

Regarding this electrophotographic photoreceptor, an electrostatic copy number tester [S
Electrophotographic characteristics were measured using a dynamic method using P-428J (Kawaguchi Electric Seisakusho Wave).

That is, the surface of the photosensitive layer of the photoreceptor was charged with a charging voltage of -6 KV.
The surface potential when charged for seconds is ■Δ.Next, the light from a tungsten lamp is irradiated so that the illuminance on the photoreceptor surface is 351ux, and the surface potential is changed from -600V to -110V.
Surface potential after exposure to light required to attenuate to 0■ (
Residual potential) VR was determined for each.

Further, similar measurements were repeated 1.00 times.

The results are shown in Table 1.

Comparative Example (1) Using an α-stilbene derivative represented by the structural formula below as a carrier transport substance, a comparative photoreceptor was prepared in the same manner as in Example 1, and the same measurements as in Example 1 were carried out. .

The results are shown in Table 1.

Table 1: As is clear from the above results, 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 repetition stability. It is excellent.

Examples 2-10 Exemplary compounds (2)l(5) as carrier transport substances.

(10), (12), (14), (18), (
An electrophotographic photoreceptor of the present invention was produced in the same manner as in Example 1, except that 20), (24), and (26) were used.

Regarding these electrophotographic photoreceptors, the same as in Example 1-B was used. Measurements were carried out in the following manner. The results are shown in Table 2.

Table 2 Table 28 - Example 11 1 part by weight of a bisazo pigment represented by the following structural formula and a polymethyl methacrylate resin [Guillanard B1t-
801 (manufactured by Mitsubishi Rayon Co., Ltd.) was added to 100 parts by weight of 1,2-dichloroethane, and dispersed in a ball mill for 24 hours. The resulting liquid was coated so that the film thickness after drying was 0.4μ to generate carriers. formed a layer.

Next, exemplified compound (22) 7. is used as a carrier transport substance.
5 parts by weight and polycarbonate resin "Panlite 113"
00J (manufactured by Ondai Kasei Co., Ltd.) dissolved in 100 parts by weight of 1,2-dichloroethane was applied to form a carrier transport layer such that the film thickness after drying was approximately 15 μm. An electrophotographic photoreceptor of the invention 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 was prepared in the same manner as in Example 11, except that a compound IL 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.

Table 3 Example 12 1 part by weight of a bisazo pigment represented by the following structural formula and a polycarbonate resin "Panlite 11300 J (
1 part by weight (manufactured by Ondai Kasei Co., Ltd.) and 100 parts by weight of Tetrahydro 7 Run 100
A carrier generation layer was formed by applying a solution which was dispersed in a ball mill for 24 hours in addition to parts by weight so that the film thickness after drying was 0.4 μl.

Next, an exemplary compound (7) was added thereon as a carrier transport substance.
) 7.5 parts by weight, polycarbonate) 10 parts by weight of 11,300 J and 100 parts by weight of Tetrahydro 7-Ran 100
An electrophotographic photoreceptor of the present invention was prepared by applying a solution dissolved in parts by weight so that the film thickness after drying was 8 μM.

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

Further, this electrophotographic photoreceptor has an electrophotographic copy number "U-Dix".
When the image was copied by attaching it to a 1550HRJ, a copied image was obtained that was faithful to the original, had high contrast, and had excellent gradation. This did not change even after 50,000 copies were repeated.

Table 5 shows the electrophotographic properties after copying at 50,000 fby.

Comparative Example (3) A comparative photoreceptor was prepared in the same manner as in Example 12, except that a stilbene 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 4 were obtained.

Furthermore, when the image was copied in the same manner as in Example 12, an image similar to that in Example 12 was initially obtained, but from around 2,000 Cobys, fogging became noticeable; after 50,000 Cobys of soil compaction, J? l) increased and only images with low contrast were obtained.

Table 5 shows the electrophotographic photoreceptor after 50,000 copies.

Below is the blank space Table 4 Table #5 Table Example 13 Consisting of vinyl chloride-vinyl acetate-maleic anhydride copolymer "Nisrex MP-10J (manufactured by Block Chemical Co., Ltd.)" on a conductive support made of a polyester film with aluminum vapor-deposited. An intermediate layer with a thickness of 0.1 μl was provided.

Next, an exemplified compound (2) is added thereon as a carrier transport substance.
4) A carrier transport layer was formed by dissolving 7.5 parts by weight of polycarbonate resin and 10 parts by weight of polycarbonate resin in 100 parts by weight of tetrahydrofuran so that the film thickness after drying was 15 μm.

Furthermore, dibromoanthrone used in Example 1 [Monolite Red 2YJ (manufactured by ICI) 1 part by weight,
Polycarbonate resin [Panrai] L-1250J 2
parts by weight and 1.5 parts by weight of exemplary compound (24), 70 parts by weight of dichloromethane and 3 parts by weight of 1.1.2-)lichloroethane.
The electrophotographic photoreceptor of the present invention was prepared by adding 0 parts by weight and dispersing it in a ball mill for 24 hours, and then applying the solution by spraying to provide a carrier generation layer having a thickness of 5 μm after drying.

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

As is clear from the results in Table 6 and above, the electrophotographic photoreceptor of the present invention is excellent in acceptance potential, sensitivity, and residual potential characteristics, and is also extremely excellent in repeated stability.

Examples 14-20 Exemplary compounds (4) and (7) as carrier transport substances.

A photoreceptor of the present invention was produced in the same manner as in Example 11, except that (11), (23), (25), (30), and (34) were used. When these photoreceptors were measured in the same manner as in Example 11, the results shown in Table 7 were obtained.

Table 7 (Effects of the Invention) According to the present invention, an excellent photoreceptor having high sensitivity and extremely stable characteristics upon repeated use can be obtained.

[Brief explanation of the drawing]

FIGS. 1 to 6 show P of the electrophotographic photoreceptor of the present invention, respectively.
Ii represents a cross-sectional view showing an example of a mechanical complementary configuration. 1... Conductive support 2... Carrier generation layer 3... Carrier transport layer 4... Photosensitive layer 5... Intermediate layer 6... Layer containing a carrier transport substance 7... Carrier Generated substance 8... Il 1 layer applicant Konishiroku Photo Industry Co., Ltd. Figure 1 Figure 2

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor comprising a photosensitive layer containing a compound represented by the following general formula [I] on a conductive support. General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [However, R_1 in the formula is a hydrogen atom, a halogen atom, a substituted,
Represents an unsubstituted alkyl group, a substituted or unsubstituted alkoxy group. R_2 represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. R_3 and R_4 may be the same or different and may be substituted,
Represents an unsubstituted aryl group. Ar represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted naphthylene group. n represents an integer of 0, 1 or 2. ]