JPS63235946A - 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 R1-R4 each may be the same or the different with each other, and are each hydrogen or halogen atom. or a substd. or an unsubstd. alkyl group or a substd. or an unsubstd. alkoxy group, (n) is an integer of 0, 1 or 2. Thus, the 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 the 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]

Conventional electrophotographic photoreceptors have a photosensitive layer containing an inorganic photoconductive compound such as selenium, zinc oxide, cadmium sulfide, or silicon as a main component. Photoreceptors 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 photoconductive compounds as main components.

For example, Japanese Patent Publication No. 10496/1983 describes an organic photoreceptor comprising a photosensitive layer containing poly-N-vinylcarbazole and 2,4,7-)linitro-9-ole7ene. 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.

[Problem that the invention seeks to solve]

Although some electrophotographic photoreceptors using carrier transport materials such as those described above exhibit relatively excellent electrophotographic performance, their durability against light, ion, or electrical loads is low, and performance may deteriorate after repeated use. It does not fully satisfy practical requirements due to instability, deterioration, etc., and it is desired to develop a carrier transport material that has even better carrier transport performance and exhibits stable performance for long-term use. It was rare. Furthermore, the need to incorporate organic photoreceptors into 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 carried out in order to solve these problems and provide a photoreceptor with extremely high sensitivity and high durability.

[Means for solving problems]

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

General formula [I] In the formula, R, R2, R, and R1 may be the same or different and represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkoxy group, Preferably, it represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 4 carbon atoms.

n 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 [I] is utilized, and this is used as a carrier for a so-called functionally separated electrophotographic photoreceptor in which carrier generation and transport are performed using separate substances. By using it as a transport material, it has excellent coating properties, excellent electrophotographic properties such as charge retention, sensitivity, and residual potential, and has little fatigue deterioration even after repeated use, and is stable against heat and light. It is possible to create an electrophotographic photoreceptor that can exhibit such 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 CI), and can also be used in combination with other photoconductive substances. Good too.

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.

\, Hereinafter referred to as Shimokin.--7 Exemplary Compound 1l--1- The carrier transporting substance described above can be easily synthesized by a known synthesis method. For example, U.S. Patent 4,265,990
You can refer to the method described in No.

Synthesis example (synthesis of exemplified compound (1)) 1] + p-short biphenyl 209 in a Mitsuro flask
(0.05 mol) and carbazole 16.711 (0.1
mole), anhydrous potassium carbonate 20.7+? (0.15 mol), 3 g of copper powder and tetrahydrothio7ene-1,1-
Dioxide 50+yl was added and the mixture was heated and stirred at 220°C to 230°C for 40 hours. Add 300 zl of cooled condensate, heat and stir, remove water by decantation, and add 300 zl of condensed water.
Add a liter of water and decant.

Add methanol 300j11, stir to dissolve unreacted raw materials, and filter the solid content.Toluene/n-hexane 11:
It was recrystallized twice from a mixed solvent of 1 and 5.

u+p, 173-174℃ Elemental analysis value calculation value C36H2,N2C:89.22%H:5,
00% N: 5.78% Actual value C: 89, 03% H: 5.12% N: 5.83% and 484 molecular ion peaks were observed in the FD spectrum, indicating that the target product was synthesized. It was confirmed.

The carrier transporting 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.

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) Chlorinated Vinyl-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. As described above, when the photosensitive layer 4 has a 2N structure, an electrophotographic photoreceptor having the best electrophotographic properties can be obtained. Therefore, in the present invention, as shown in FIGS. 5 and 6, a photosensitive layer 4 formed by dispersing a fine particulate 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 4 has a two-layer structure, 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 3 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. Because there is.

Further, the carrier generation layer 2 constituting the two-layered photosensitive layer 4 can be formed directly on the conductive support 1 or the carrier transport layer 3, or by the following method after providing an adhesive layer or a barrier layer as necessary. can be formed by

(1) Vacuum evaporation method (2) The carrier-generating substance is made 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.

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.
．． It 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 μm to 30 μm thick. 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 may include 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.

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.

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.

Lifting margin ρ (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 plastic film by lamination or vapor deposition. (3) A support such as paper or plastic film. A layer of a conductive compound such as a conductive polymer, indium oxide, or tin oxide is provided by coating or vapor deposition.For forming the constituent layers such as the carrier transport layer and the carrier generation layer according to the present invention, vacuum vapor deposition, sputtering, CV
A vapor deposition method such as D, or a coating method such as dipping, spraying, blade, or roll method may be used as desired.

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.

〔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.Secondly, a conductive support made of vinyl chloride-vinyl acetate-maleic anhydride copolymer [S-LEC MP-101 (manufactured by Tanezu Kagaku Co., Ltd.) with a thickness of 0.5 mm. An intermediate layer with a thickness of 1 μm was provided.

On top of that, 1 part by weight of dibromoanthrone [Monolite Red 2YJ (manufactured by ICI) represented by the following structural formula] and 0.5 part by weight of polycarbonate resin [Panlite L-1250J (manufactured by Ondai Kasei) were added. A carrier-generating layer was formed by mixing the mixture with 100 parts by weight of 1,2-nochloroethane and dispersing it in a ball mill for 24 hours, and applying the solution 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) 01 fat (10 parts by weight of Panlite L-1250J) dissolved in 100 parts by weight of 1,2-dichloroethane was applied to the carrier so that the film thickness after drying was 15 μm. A transport layer was formed to produce an electrophotographic photoreceptor of the present invention.

Regarding this electrophotographic photoreceptor, electrostatic copying machine test equipment rS
The electrophotographic characteristics were measured using a dynamic method using P-428J (newly manufactured by Kawaguchi Electric Seisakusho).

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 ﾆ^, and then the illuminance of the light from the tungsten lamp on the surface of the photoreceptor is 35 lux
The surface potential (residual potential) VR after exposure required to reduce the surface potential from -600V to -100V was determined.

Further, similar measurements were repeated 100 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 a carbazole derivative represented by the following structural formula was used as a carrier transport substance, and the same measurements as in Example 1 were performed.

The results are shown in Table 1.

As is clear from the results shown in the margin below, the electrophotographic photoreceptor of the present invention of Example 1 was clearly superior to the photoreceptor of Comparative Example (1) in terms of sensitivity, residual potential characteristics, and repetition stability. It is.

Examples 2-10 Exemplary compounds (2) and (4) as carrier transport substances.

(8), (13), (22), (27), (
An electrophotographic photoreceptor of the present invention was produced in the same manner as in Example 1, except that 32), (35), and (43) were used.

Regarding these electrophotographic photoreceptors, the same 281 as in Example 1 was used. Measurements were carried out in the following manner. 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-8
0] (manufactured by Mitsubishi Rayon Co., Ltd.) in 100 parts by weight of 1,2-dichloroethane, and dispersed in a ball mill for 24 hours. The liquid was then applied to a carrier so that the film thickness after drying was 0.4 μm. A generation layer was formed.

Next, exemplified compound (22) 7. is used as a carrier transport substance.
5 parts by weight and polycarbonate resin [13 parts by weight in Panlite]
A carrier transport layer was formed by dissolving 10 parts by weight of 00J (manufactured by Ondai Kasei Co., Ltd.) in 100 parts by weight of 1,2-dichloroethane and applying it to a film thickness of 15 μm after drying. An electrophotographic photoreceptor of the invention was produced.

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 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-13004 (
1 part by weight (manufactured by Ondai Kasei Co., Ltd.) and 100 parts by weight of tetrahydrofuran.
A carrier-generating layer was formed by adding a part by weight and dispersing the solution in a ball mill for 24 hours so that the film thickness after drying would be 0.4 μm.

Next, an exemplary compound (7) was added thereon as a carrier transport substance.
) 7.5 parts by weight, polycarbonate resin [11300J10fil parts of Panlite dissolved in 100 parts by weight of tetrahydrofuran, the film thickness after drying was 18μl
An electrophotographic photoreceptor of the present invention was prepared by applying the following coatings.

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

Furthermore, this electrophotographic photoreceptor is used in an electrophotographic copying machine [U-Bix
When the image was copied by attaching it to a 1550MRJ, a copied image was obtained that was faithful to the original image, had a high foot last, and had excellent gradation. This did not change even after 50,000 copies were repeated.

Further, the electrophotographic characteristics after 50,000 copies are shown in Table 5.

Comparative Example (3) A comparative photoreceptor was prepared in the same manner as in Example 12 using a stilbene derivative represented by the following structural formula as a carrier transporting 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 an image was copied in the same manner as in Example 12, an image similar to that in Example 12 was initially obtained, but fog started to become noticeable around 3,000 cobys and after 50,000 cobys, the fog increased and only an image with low contrast was obtained. I couldn't get it.

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

Below is the gold ^^ Table 4 Table 5 Example 13 Vinyl chloride-vinyl acetate-maleic anhydride copolymer [Nisrex MF-10J (Tanesui Kagaku Co., Ltd.) An intermediate layer having a thickness of 0.1 μm 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, 1 part by weight of dibromoanthrone "Monolite Red 2YJ (manufactured by ICI)" used in Example 1,
Polycarbonate resin [Panlite 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 dichloromethane (1.1.2-)
An 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 form a carrier generation layer having a thickness of 5 μl 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, as well as extremely excellent in repeatability stability.

Examples 14-20 Exemplary compounds (5) and (6) as carrier transport substances.

Photoreceptors of the present invention were prepared in the same manner as in Example 11 except that (16), (17), and (34L (36L (40)) were used. These photoreceptors were measured in the same manner as in Example 1. As a result, 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 drawings]

FIGS. 1 to 6 show 8 of the electrophotographic photoreceptor of the present invention, respectively.
! FIG. 3 is a cross-sectional view showing an example of a mechanical 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... Protective layer applicant Konishiroku Photo Industry Co., Ltd. Figure 1 Figure 3 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, in the formula, R_1, R_2, R_3, and R_4 may be the same or different, and include hydrogen atoms, halogen atoms,
Represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkoxy group. n represents an integer of 0, 1 or 2. ]