JPS63253951A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body having high sensitivity and high durability by providing a photosensitive layer essentially consisting of a specific org. photoconductive compd. to said body. CONSTITUTION:This photosensitive body has the photosensitive layer constituted by being provided with the layer contg. the compd. expressed by the formula I on a conductive base. In the formula I, X denotes an oxygen atom., sulfur atom., imino group; R1 denotes a hydrogen atom., halogen atom., alkyl group, alkoxy group; R2 denotes an alkyl group, aralkyl group, aryl group; R3, R4 denote an alkyl group, aralkyl group, aryl group; n denotes 0 or 1. The photosensitive body which has the high sensitivity and is stable in characteristics at the time of iterative use is thereby 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]

Conventionally, as electrophotographic photoreceptors, inorganic photoreceptors having a photosensitive layer mainly composed of an inorganic photoconductive compound such as selenium, zinc oxide, cadmium oxide, silicon, etc. have been widely used. However, these were not necessarily satisfactory in terms of sensitivity, thermal stability, moisture resistance, durability, etc. For example, selenium is difficult to manufacture because its properties as an electrophotographic photoreceptor deteriorate when it crystallizes, and it also crystallizes due to heat, fingerprints, etc. and deteriorates its performance as an electrophotographic photoreceptor. Cadmium sulfide and zinc oxide had problems with moisture resistance and durability.

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

For example, Japanese Patent Publication No. 10496/1983 describes a fi photoreceptor comprising a photosensitive layer containing poly-N-vinylcarbazole and 2,4,7-)dinitro-9-fluorenone. However, this photoreceptor is not necessarily satisfactory in terms of sensitivity and durability. Attempts are being made to develop the body. 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 Japanese Patent No. 425, No. 58-178362, 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, ozone, or electrical loads is weak, and performance may deteriorate after repeated use. It does not satisfy practical requirements due to stability, deterioration, etc., 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. Ta. Furthermore, the demand for incorporating organic photoreceptors into electrophotographic copying machines that can copy at higher speeds has been increasing in recent years, and there has been a desire to develop photoreceptors with higher sensitivity, higher durability, and faster speeds. .

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 has been solved by an electrophotographic photoreceptor having a photosensitive layer comprising a layer containing a compound represented by the following general formula (r) on a conductive support.

General formula CI) In the formula, X represents an oxygen atom, a sulfur atom, or an imino group.

R represents a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group; R2 represents an alkyl group, an aralkyl group, or an aryl group; R3 and R4 may be the same or different; an alkyl group, an aralkyl group, or an aryl group; , R
+, R2, R3, and R< may be substituted.

n represents O or 1.

That is, in the present invention, the carrier transport ability of the compound represented by the general formula C1) is utilized and used as a carrier transport material for a functionally separated electrophotographic photoreceptor in which carrier generation and transport are performed by separate substances. By using this material, the film has excellent physical properties, excellent electrophotographic properties such as charge retention, sensitivity, and residual potential, and has low fatigue deterioration even after repeated use, and stable properties against heat and light. It is possible to create an electrophotographic photoreceptor that can exhibit the following 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 (l), 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 (,1) include those having the following tI14 formula, but this does not limit the carrier transporting substance according to the present invention. It's not something you can do.

Exemplary Compounds The carrier transport materials described above are easily synthesized by known synthetic methods. Reference may be made, for example, to the methods described in US Pat. No. 3,765.884 and JP-A-60-162259.

Synthesis Example (Synthesis of Exemplary Compound (1)) The above 3-methylbenzothiazolinone hydrazone < 1
) 17.9 g (0.1 mol) and 20.8 g (0.1 mol) of the above 3.3-diphenylacrolein (2) and 5 ml of acetic acid were mixed in 500 mj of ethanol! The mixture was heated under reflux for 10 hours.

After cooling, the precipitated crystals were collected and recrystallized twice from a mixed solvent of MEK and ethanol. Yield 21.59 (58.3%
).

Elemental analysis value C2s H+*N*S Calculated value C near 4.75%H:5.19%N:11.37%S:8.
68% Measured value C near 4.78%H: 5.23%N: 11.4
2% S: 8.52% and a molecular ion peak of 369 was observed in the FD mass spectrum, so it was determined that the target compound 3 (exemplified compound (1)
) was confirmed to have been synthesized.

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 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 chloride-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 a carrier-generating substance as a main component and a carrier-transporting substance of the present invention as a main component on a conductive support 1. A photosensitive layer 4 made of a laminate with a carrier transport layer 3 is provided.

As shown in FIGS. 3 and 4, this photosensitive layer 4 may be provided through an intermediate layer 5 provided on the conductive support 1.
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. A protective layer 8 may be provided directly on the photosensitive layer 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 is used as the upper layer is determined depending on whether the charging polarity is selected as 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. This is because.

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

(1) Vacuum deposition method (2) A method in which a carrier-generating substance is made into fine particles in a dispersion medium using a ball mill, a sand grinder, etc., and a dispersion obtained by mixing and dispersing with a binder as necessary is applied.

As the binder used for forming the carrier generation layer, any binder can be selected from among the binders used for 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 0.01μ to 5μ, more preferably from 0.05μ to 3μ. Further, the thickness of the carrier transport layer 3 can be changed as necessary, but is usually 5 μII to
This carrier transport layer 3 is preferably 30 μ-
The composition ratio in is preferably 0.8 to 10 parts by weight of the binder per 1 part by weight of the carrier transport material, but when forming the photosensitive layer 4 in which fine particulate carrier generating material is dispersed. 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.

(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, gold, etc. is provided on a support such as paper or plastic film by lamination or vapor deposition. (3) A thin layer of a conductive polymer or the like is provided on a support such as paper or plastic film. A layer made of a conductive compound such as indium oxide or tin oxide 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, 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-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 0-thick film made of vinyl chloride-vinyl acetate-maleic anhydride copolymer "S-LEC MF-10J (manufactured by Tanezu Kagaku Co., Ltd.)" was placed on a conductive support formed by vapor-depositing aluminum on a polyester film. A middle layer of .1μ ring was provided.

On top of that, 1 part by weight of dibromoanthrone [Monolite Red 2Y] (manufactured by ICI) represented by the following structural formula and polycarbonate resin "Panlite L-1250" are added.
(manufactured by Ryotai Kasei Co., Ltd.) in 100 parts by weight of 1,2-dichloroethane, and dispersed in a ball mill for 24 hours. The liquid was coated to a dry film thickness of 1 μm to form a carrier. A generation layer was formed.

Furthermore, exemplified compound (1) is added as a carrier transport substance.
7.5 parts by weight and polycarbonate resin “Panlite L-
10 parts by weight of 1250J and 10 parts by weight of 1,2-dichloroethane
A carrier transport layer was formed by applying a solution dissolved in 0 parts by weight to a film thickness of 15 μm after drying, thereby forming an electrophotographic photoreceptor of the present invention.

About this electrophotographic photoreceptor Electrostatic copying paper testing device rSP
-428'' (manufactured by Kawaguchi Electric Seisakusho), the electrophotographic characteristics were measured using a dynamic method.

That is, the surface potential V^ is obtained when the surface of the photosensitive layer of the photosensitive member is charged with a charging voltage of -6 KV for 5 seconds, and then the surface potential is determined by irradiating light from a tungsten lamp so that the illuminance of the photosensitive member surface is 351u+x. -to 600V
Surface potential after exposure required to attenuate to ov (
Residual potential) VR was determined for each.

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 an H3 hydrazone dielectric represented by the following structural formula was used as a carrier transport material, and measurements were carried out in the same manner as in Example 1.

The results are shown in Table 1.

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 repetition stability. be.

Examples 2 to 10 In place of the exemplified compound (1) as a carrier transport substance, compound (2), (4), (6), (10), (16), (18)
), <21), (30).

An electrophotographic photoreceptor of the present invention was produced in the same manner as in Example 1 except that (32) was 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 structural formula below and a polymethyl methacrylate resin "Dyanal BR-80J (manufactured by Mitsubishi Rayon Co., Ltd.) 0 A carrier-generating layer was formed by adding 100 parts by weight of 1,2-dichloroethane to 100 parts by weight of 1,2-dichloroethane, dispersing the mixture in a ball mill for 24 hours, and applying the solution to a dry film thickness of 0.4 .mu.m.

Next, Exemplified Compound (3) 7.5 as a carrier transport substance
Part by weight and polycarbonate resin "Panlite 1130"
0J (manufactured by Ryotai Kasei Co., Ltd.) in 100 parts by weight of 1,2-dichloroethane was applied to form a carrier transport layer to form a layer having a thickness of 5 μm after drying. An electrophotographic photoreceptor was prepared.

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.

Example 12 Bisazo pigment 1 represented by the following structural formula was placed on a conductive support formed by vapor-depositing aluminum on a polyester film.
Part by weight and polycarbonate resin [1130 to Panlite]
A carrier-generating layer was formed by applying a solution prepared by dispersing 0.5 parts by weight of 0J (manufactured by Ryotaikagaku Co., Ltd.) and 100 parts by weight of tetrahydrofuran in a ball mill for 24 hours so that the film thickness after drying was 0.4 μm. did.

Next, an exemplified compound (5) was added thereon as a carrier transport substance.
) 7.5 parts by weight of polycarbonate resin "Panlite - 10 parts by weight of 11300J" and 100 parts by weight of tetrahydrofuran.
An electrophotographic photoreceptor of the present invention was prepared by applying a solution dissolved in parts by weight to give a film thickness of 18 μm after drying.

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 was used in an electrophotographic copying machine "U-B i
x 1550M RJ and copied the image, 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 repetitions.

Further, the electrophotographic properties 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, 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 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 the fog started to become noticeable after around 2,000 copies, and the fog increased after 50,000 copies were copied. Only images with low contrast were obtained.

Furthermore, the electrophotographic properties after 50,000 copies are shown in Table 5.

Table 4 Table 5 Example 13 Vinyl chloride-vinyl acetate-maleic anhydride copolymer "S-LEC MF-10J (manufactured by Suikagaku Co., Ltd.)" was prepared on a conductive support made of a polyester film with aluminum vapor-deposited.
An intermediate layer with a thickness of 0.1μ was provided thereon, and then 7.5 parts by weight of exemplified compound (3) as a carrier transport substance and polycarbonate resin [Panlite K-130] were provided.
A carrier transport layer was formed by coating a solution prepared by dissolving 10 parts by weight of 0J in 100 parts by weight of tetrahydrofuran so that the film thickness after drying was 15 μm.

Furthermore, 1 part by weight of the dibromoanthron "Monolite Red 2YJ (manufactured by IC1) used in Example 1, and polycarbonate resin [Panlite L-1250
J 2 parts by weight, and exemplified compound (3N, 5 parts by weight,
70 parts by weight of dichloromethane and 30 parts by weight of 1.1.2-trichloroethane were added and dispersed in a ball mill for 24 hours, and a solution was applied by spraying to form a carrier generation layer having a thickness of 5 μm after drying. An electrophotographic photoreceptor was created.

Measurements were carried out in the same manner as in Example 1, except that the charging voltage of this electrophotographic photoreceptor was changed to +6 KV, and the results shown in Table 6 were obtained.

As is clear from the results shown in Table 6, 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 to 20 Exemplary compound (3) was replaced with the same compound (3) as a carrier transport substance.
8), (11), (15), (20), (38), (3
A photoreceptor of the present invention was produced in the same manner as in Example 11 except that 1) and (39) were used. These photoreceptors were measured in the same manner as in Example 1, and 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 each represent a cross-sectional view showing an example of the mechanical structure of the electrophotographic photoreceptor of the present invention. 1 ... Conductive support 2 ... Carrier generation layer 3 ... Carrier transport layer 4 ... Photosensitive layer 5 ... Intermediate layer 6 ... Layer containing carrier transport substance 7 ... Carrier Generated substance 8...Protective 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, in the formula, X represents an oxygen atom, a sulfur atom, an imino group,
R_1 represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, R_2 represents an alkyl group, an aralkyl group, an aryl group, R_3 and R_4 may be the same or different, and represent an alkyl group, an aralkyl group, an aryl group. where R_1, R_2, R_3, and R_4 may be substituted. n represents 0 or 1. ]