JPS60164751A - Photosensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body high in sensitivity and low in residual potential by using a specified phenothiazine deriv. as a carrier transfer material for a functionally separated type photosensitive body. CONSTITUTION:A phenothiazine deriv. capable of effectively constituting an electrophotographic sensitive body as a carrier transfer material in combination with an optional carrier generating material is a compound represented by formula [ I ] in which A is optionally substd. alkyl or optionally substd. aryl; R is alkyl, alkoxy, halogen, or amino; and n is 0, 1, or 2, and when n is 2, R may be different. The most excellent electrophotographic characteristics can be obtained by laminating on the conductive substrate 1 an interlayer 5, when needed, the carrier generating layer 2, and the carrier transfer layer 3 adjacent to this layer 2, and thus forming the photosensitive layer of 2-layer structure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photoreceptor, and more particularly to a novel electrophotographic photoreceptor having a photosensitive layer containing a carrier-generating substance and a carrier-transporting substance.

It was widely known that it had a light layer. However, these are not necessarily satisfactory in terms of properties such as thermal stability and durability, and there are also problems in manufacturing and handling.

On the other hand, photoreceptors having a photosensitive layer containing an organic photoconductive compound as a main component are relatively easy to manufacture, inexpensive, easy to handle, and are generally more heat sensitive than selenium photoreceptors. It has many advantages such as excellent stability, and has attracted a lot of attention in recent years. The most well-known such organic photoconductive compound is poly-N-vinylcarbazole, and a charge transfer complex formed from this and a Lewis acid such as 2,4,7-dolinitro-9-fluorenone, etc. Photoreceptors having a photosensitive layer as a main component have already been put into practical use.

On the other hand, photoconductors are known that have a functionally separated photoconductor layer, such as a laminated type or a dispersion type, in which the carrier generation function and the carrier transport function of the photoconductor are assigned to separate substances. A photoreceptor having a photosensitive layer consisting of a carrier generation layer consisting of a thin selenium layer and a carrier transport layer containing poly-N-vinylcarbazole as a main component has already been put into practical use.

However, since poly-N-vinylcarba''/- lacks flexibility, its coating is hard and brittle, and is prone to cracking and film peeling. Therefore, photoreceptors using it have poor durability. If a plasticizer is added to improve this defect, the residual potential will increase when subjected to the electrophotographic process, and as it is repeatedly used, the residual potential will accumulate and gradually cause capillarity in the copied image. In addition, since low-molecular organic photoconductive compounds generally do not have film-forming ability, they are used in combination with any binder, and therefore the type and composition ratio of the binder used Although it is preferable to select K in that the physical properties of the film or the photosensitive characteristics can be controlled to a certain extent, the types of organic photoconductive compounds that have high compatibility with the binder are limited. However, in reality, there are not many materials that can be used in the construction of the photosensitive layer of a photoreceptor, especially an electrophotographic photoreceptor.

For example, 2,5-bis(p-diethylaminophenyl)-1,3,4-oxadiazole described in U.S. Pat. No. 3,189,447 is a material for the photosensitive layer of an electrophotographic photoreceptor. Since it has low compatibility with binders that are usually preferably used as binders, it is mixed with binders such as polyester and polycarbonate in the ratio required to obtain favorable electrophotographic properties. When a photosensitive layer is formed, oxadiazole crystals begin to precipitate at temperatures above 50° C., resulting in a disadvantage that electrophotographic properties such as charge retention and sensitivity deteriorate.

On the other hand, the diarylalkane derivatives described in U.S. Pat. No. 3,820,989 do not usually have a problem with their compatibility with binders, but their stability against light is low. When this is used in the construction of a photosensitive layer of a photoreceptor for anti-α transfer type electrophotography in which charging and exposure are repeated, it has the disadvantage that the sensitivity of the photosensitive layer gradually decreases.

Also, U.S. Patent No. 3,274,000, Japanese Patent Publication No. 4
7-36428 describes different types of phenothiazine derivatives, but all of them have the drawbacks of low photosensitivity and low stability during repeated use.

The reality is that a carrier transporting material having practically satisfactory characteristics for producing an electrophotographic photoreceptor has not yet been found.

[Purpose of the invention]

An object of the present invention is to provide a highly sensitive photoreceptor.

The purpose of the spear of the present invention is to make it a highly sensitive layer! An object of the present invention is to provide an electrophotographic photoreceptor with a low JIWlt.

Another object of the present invention is to maintain stable characteristics for a long time without causing fatigue deterioration due to repeated use when used as a photoreceptor for electrophotography of a repetitive transfer type in which charging, exposure, development, and transfer steps are repeated. An object of the present invention is to provide an electrophotographic photoreceptor having excellent durability over a long period of time.

[Structure of the invention]

As a result of intensive research to achieve the above object, the present inventors discovered that the object could be achieved by using a specific phenothiazine derivative as a carrier transport material for a functionally separated photoreceptor, and completed the present invention. This is what I did.

The above object has been achieved by a photoreceptor characterized in that it has a photosensitive layer containing a phenothiazine derivative represented by the following general formula on a conductive support.

In the general formula, A represents a substituted or unsubstituted alkyl group 1 or a substituted or unsubstituted aryl group. Examples of preferable alkyl groups include methyl group, ethyl group, propyl group, methoxyethyl group, benzyl aSp-methoxybenzyl group, phenethyl group, etc., and preferable examples of aryl groups include 7-enyl group, Examples include p-methylphenyl group, p-methoxypheni'' group, p-N, N-diethylaminophenyl group, and the like.

Examples of substituted alkyl groups and substituted aryl groups include alkyl groups (e.g. methyl, ethyl, propyl), alkoxy groups (e.g. methoxy, ethoxy, propyoxy), amino groups (e.g. diethylamino, dimethylamino). group), and halogen atoms.

R is an alkyl group (e.g., methyl group, ethyl group, ↓-propyl group, etc.), an alkoxy group (e.g., methoxy group, ethoxy group, etc.), a halogen atom, or an amino group (e.g., N, N
-diethyl ai) group, N-N-dimethylamino group, N
-methyl-N-phenylamino group, etc.), where n is 0
．． represents an integer of 1 or 2, and when n is 2, R may select a different group.

That is, in the present invention, 1) the carrier transport ability of the phenothiazine derivative represented by the above general formula is utilized to create a carrier transport material in the photosensitive layer of a so-called functionally separated photoreceptor in which carrier generation and transport are performed using separate substances. By using it as a coating, it has excellent physical properties, and has excellent electrophotographic properties such as charge retention, sensitivity, and residual potential.It also shows little fatigue deterioration even after repeated use, and the above-mentioned properties do not change. It is possible to create an electrophotographic photoreceptor that can exhibit stable characteristics.

Specific examples of the phenothiazine derivatives represented by the above general formula that are effective in the present invention include those having the following structural formula, but are not limited thereto.

Exemplary compound C snow mountain straight CH.

C! Mountain Ha 9- ” C! bird 1 CH.

CH.

CH.

so CH.

11- CH.

Police station CH.

CH1 C.H.

12-14- All of these compounds can be synthesized by known methods.

Synthesis Example 11 Synthesis of Exemplified Compound A-(1) 10 g of phenothiazine was mixed with 213 ml of DMF (NtN-dimethylformamide) in FCm, and 40 ml of ethyl iodide was added to it.
1 was added thereto, and the mixture was heated under reflux for 16 hours. (75°C) At the end of the reaction, the internal temperature was heated to 95°C, excess ethyl iodide was removed, and the mixture was poured into water. The resulting precipitate was collected by filtration and recrystallized from ethanol to obtain 11.0 g of white crystals, melting point 103-1.
04℃ Yield 96% Synthesis Example 2 Synthesis of Exemplary Compound A-(7) 20g of phenothiazine, 40g of iodobenzene, and 20g of potassium carbonate
, 0.2g of copper powder was mixed and heated to 1190°C to 200°C (bath temperature).
The mixture was heated under reflux for 5 hours. After the reaction was completed, excess iodobenzene was removed by steam distillation and the resulting precipitate was collected by filtration.

5. Recrystallized from ethanol to obtain 21.5 g of white crystals. Melting point: 95°C. Yield: 77.8%.

Synthesis Example 3 Synthesis of Exemplified Compound A-(9) 5.0 g of phenothiazine and p-iodoanisole'y;og were combined, 8 g of 10 d% nitrobenzene potassium carbonate and 0.1 g of copper powder were added, and the mixture was heated at 180°C to 190°C. The mixture was heated and stirred at ℃ (internal temperature) for 10 hours. After the reaction was completed, the intoxicant was removed by steam distillation, and the residue was recrystallized from ethyl acetate-methanol to obtain 5.0 g of white crystals.

Melting point, 173-174°C, yield 65.6.

17- Synthesis Example 4 Synthesis of Exemplified Compound A-(23) 4.0 g of phenothiazine and 8.4 g of NtN diethyl-p-iodoaniline were dissolved in 15 rnl of trobenbin, and 5 g of potassium carbonate and 0.19 copper powder were added to 190 g. ~20? ℃
The mixture was heated and stirred for 16 hours. After the reaction, the solvent was removed by steam distillation, and the resulting precipitate was collected by filtration and recrystallized from ethanol to obtain 4.2 g of pale yellow crystals.

Melting point: 157°C, yield: 6o.

The phenothiazine derivative can be used as a carrier transporting material in combination with any carrier generating material to effectively constitute an electrophotographic photoreceptor. Examples of carrier-generating substances used in the present invention include inorganic photoconductors such as selenium, selenium alloys, and amorphous silicon, as well as organic dyes and pigments having carrier-generating ability. Particularly preferred organic dyes/pigments here include polycyclic quinone pigments and monoazo dyes,
Azo dyes such as bisazo dyes and trisazo dyes can be obtained.

The photoreceptor of the present invention can also be constructed by containing the phenothiazine derivative according to the present invention in the same layer as the carrier-generating substance described above; It is particularly preferable to constitute a laminate of a carrier transport layer containing the above-mentioned phenothiazine derivative as a carrier transport substance and a carrier transport layer.

Since the phenothiazine derivative of the present BJIk does not have film-forming ability, when it is used to form a photosensitive layer, it is preferable to use it together with a binder.

The preferred binder used in the present invention is a hydrophobic, high dielectric constant, electrically insulating film-forming polymer. Examples of such polymers include the following.

B - (1) Borinutylene B - (21 Polyvinyl chloride B - (31 Polyvinylidene chloride B - (4) Polyvinyl acetate B - (5) Acrylic resin B - (6) Methacrylic resin B - (7) Polyester B - ( 8) Polycarbonate B-(91 phenol formaldehyde resin) These binders can be used alone or in combination of two or more types, or as a copolymer containing at least one type of monomer constituting the above polymer. However, the binder used in the present invention is not limited to these.

As shown in FIG. 1, FIG. 2, FIG. 3, and FIG. A photoreceptor having the best electrophotographic properties can be obtained when the carrier transport layer 3 is provided adjacent to the carrier transport layer 3 and the photosensitive layer has a two-layer structure. However, as shown in FIGS. A photoreceptor in which fine particles 7 of a carrier-generating substance are dispersed in a photosensitive layer 6 containing a carrier-transporting substance as a main component on a photosensitive support 1 via an intermediate layer 5 if necessary is also effectively used in the present invention. be able to.

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 by K whether the charging polarity is positive or negative. That is, when used with negative charge, it is advantageous to use the carrier transport layer 3 as an upper layer, because the phenothiazine derivative of the present invention in the carrier transport layer is a substance having a high transport ability for holes. Because there is.

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 intermediate layer such as an adhesive layer or a barrier layer if necessary, by the following method.

(C-1) Vacuum evaporation method (C-2) Is the carrier generating substance an appropriate solvent IC? (c-3) The carrier-generating material is made into fine particles in a dispersion medium using a ball mill, homomixer, sand mill, colloid mill, etc., and mixed and dispersed with a binder as necessary. The thickness of the carrier generation layer 2 formed in this way is 0.
．． It is preferably from 0.01 to 5 microns, more preferably from 0.05 to 3.91 microns.

Further, the thickness of the carrier transport layer 3 can be changed as necessary, but it is usually preferably 5 to 30 nm. 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 substance whose main component is the heptadylazine derivative described above. When forming the photosensitive layer 4 in which a carrier-generating substance such as the above is dispersed, it is preferable to use a binder in an amount of 5 parts by weight or less per 1 part by weight of the carrier-generating substance.

In addition, when the carrier generation layer 2 is configured as a dispersion type layer using binding subpressure, 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.

Incidentally, the conductive support 1 used in the construction of the photoreceptor of the present invention
For example, a metal plate 1 or a paper that has been made conductive by coating, vapor depositing, or coating with a thin metal layer such as a conductive polymer, a conductive compound such as indium oxide, or a thin metal layer such as aluminum ζ 1 palladium or gold oxide. , plastic 7tum, etc. are used22-. The intermediate layer 5 such as an adhesive layer or a barrier layer may be made of organic polymers such as gelatin, casein, starch, polyvinyl alcohol, vinyl acetate, ethyl cellulose, carboxymethyl cellulose, or the like, in addition to the polymer used as the binder. Aluminum oxide or the like is used.

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

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

Example 1 Selenium was vapor-deposited on a conductive support made of aluminum foil laminated on top of a polyester film to a thickness of 0.
A carrier generation layer of 5 microns was formed. in addition,
Dissolve 6 parts by weight of Exemplary Compound Part A-(9) and 10 parts by weight of polycarbonate "Panlite L-12504 (manufactured by Ondai Kasei Co., Ltd.) in a weighted part of 1,2-dichloroethane, and dry this solution. A carrier transport layer was formed by coating to a final film thickness of 11 microns, thereby producing an electrophotographic photoreceptor of the present invention.

Regarding this electrophotographic photoreceptor, electrostatic copying paper tester RS
The electrophotographic characteristics were measured using a dynamic method using a model P-428 (manufactured by Kawaguchi Electric Seisakusho).

That is, when the surface of the photoreceptor layer of the photoreceptor is charged for 5 seconds with a charging voltage of -6 KV, the surface potential VA N is then applied to the surface of the photoreceptor at an illumination intensity of 35 lu from the tungsten lamp.
Exposure amount required to attenuate the surface potential Vm by half (half-reduced exposure amount) E3 ((1u
The surface potential (residual potential) VR after irradiation with the exposure dose of x-see) and IIC30lux@sea was determined, respectively. The same measurement was repeated 100 times.

The results are shown in Table 1.

Table 1 As is clear from this table, the electrophotographic photoreceptor of the present invention has sufficient charge retention ability, has high sensitivity, has a small residual potential, and maintains good characteristics even after repeated use. It has excellent physical properties.

Comparative Example 1 A comparative photoreceptor was prepared in the same manner as in Example 1 except that phenothiazine was used. When this photoreceptor was measured in the same manner as in Example 1, the results shown in Table 2 were obtained.

As is clear from the results in Table 2 and above, the comparative photoreceptor was significantly inferior in stability during repeated use compared to the photoreceptor of the present invention of Example 1.

Examples 2 to 4 The same procedure as in Example 1 was carried out except that exemplified compound M1 (1) * A - (15), M1 ■) was used instead of exemplified compound M1 (9) as a carrier transport substance. An electrophotographic photoreceptor of the present invention was prepared. Example 1 about these photoreceptors! The initial characteristics were measured in the same manner as for /c, and the results shown in Table 3 were obtained.

Table 3 Example 5 A polyester film having a thickness of 0.05 mm made of vinyl chloride-vinyl acetate-maleic anhydride copolymer [S-LEC MIF-10J (manufactured by Tanezu Kagaku Co., Ltd.) A micron intermediate layer is placed on top of it, and then dibromoanthrone "Monolite Red 2YJ (C)
Polycarbonate "Panlite L-12" was added to a weighted part of 1,2-dichloroethane and dispersed in a ball mill.
1.5 parts by weight of 50J (manufactured by Kijin Kasei Co., Ltd.) was dissolved and thoroughly mixed, and the coating liquid was dried to a film thickness of 2 microns. A carrier-generating layer was formed by applying the coating to form a carrier-generating layer.

On top of that, a coating solution in which 6 parts by weight of Exemplified Compound A-(20) and 10 parts by weight of polyester [Vylon 200J (manufactured by Toyobo Co., Ltd.) were dissolved in parts by weight of 1,2-dichloroethane was dried. A carrier transport layer was formed by coating the film to a thickness of 11 microns, thereby forming an electrophotographic photoreceptor of the present invention. When this photoreceptor was measured in the same manner as in Example 1, the results shown in Table 4 were obtained.

Table 4 Comparative Example 2 A comparative photoreceptor was prepared in the same manner as in Example 5, except that a phenothiazine derivative having the following structural formula was used in place of Exemplified Compound A-■) as a carrier transport substance. Example 1 When measured in the same manner as in
Obtained the results in the table.

As is clear from the results shown in Table 5, the comparative photoreceptor was significantly inferior to the photoreceptor of the present invention in terms of sensitivity and repeated stability.

Example 6 A 0.1 micron thick intermediate layer made of polyester "Vy-4-lon 200J" (manufactured by Toyobo Co., Ltd.) was provided on a conductive support made of a polyester film laminated with aluminum foil.

A solution prepared by dispersing 1 part by weight of a bisazo pigment represented by the following structural formula as a carrier-generating substance in ω parts by weight of 1,2-dichloroethane was applied to SO(7) so that the film thickness after drying was 0.3 microns. A carrier generation layer was formed by coating. Furthermore, 6 parts by weight of Exemplified Compound A-(22) and polycarbonate [Panlite L-1250J (Hitsuiri Kasei Co., Ltd.)
After drying, a solution prepared by dissolving 10 parts by weight in 1.2 parts by weight of dichloroethane was coated to a film thickness of 15 microns to form a carrier transport layer, and the electrophotographic photosensitive material of the present invention was prepared. created a body. The initial characteristics of this photoreceptor were measured in the same manner as in Example 1. VA = 1010 V +E3 (z 3
．． 51ux11see * VR = OV.

In addition, this photoreceptor was used in an electrophotographic copying machine rU-B1x2000.
When the copying machine was attached to RJ (manufactured by Konishiroku Photo Industry Co., Ltd.) and a live copy test was carried out, a copy image that was faithful to the original, had high contrast, excellent gradation, and was clear was obtained. This is 1000
Even after repeating the process several times, a copy image as good as the initial one was obtained.

Example 7 An electrophotographic photoreceptor of the present invention was prepared in the same manner as in Example (6) except that a binuazo pigment represented by the following structural formula was used as a carrier generating substance.

The initial characteristics of this photoreceptor are VA=985V+E%=2.8
1ux"see + VR = OV. This was attached to an electrophotographic copying machine r U -Bix 2000 RJ (manufactured by Konishi Roku Photo Industry Co., Ltd.) and a live photo test was performed.
Even after repeating the process 0 times, a good copy image was obtained, which was the same as the initial image.

[Effects of the Invention] According to the present invention, it is possible to obtain an excellent photoreceptor having high λ sensitivity, extremely stable characteristics upon repeated use, and no problems such as toxicity.

[Brief explanation of the drawing]

FIGS. 1 to 6 each represent a 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 7 containing a carrier transporting substance...
... Carrier-generating substance agent Patent attorney No 1) Parent-in-law

Claims (3)

[Claims] (1) A photoreceptor characterized by having a photosensitive layer containing a phenothiazine derivative represented by the following general formula on a conductive support. In the general formula, A represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, R represents an alkyl group, an alkoxy group, a halogen atom or an ano group, and n is 0
, represents an integer of 1 or 2. (2) The photoreceptor according to claim 1, wherein the photoreceptor is a functionally separated type electronic triple photoreceptor comprising a photoreceptor layer containing a carrier-generating substance and a carrier-transporting substance provided on a conductive support. body. (3) The photosensitive layer according to claim 1 or 2, wherein the photosensitive layer is constituted by a laminate of a carrier generation layer containing a carrier generation substance and a carrier transport layer containing a carrier transport substance. Photoreceptor.