JPS6318358A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body having excellent sensitivity, repetitive characteristics, durability, etc., by incorporating an azo compd. having a specific structure as a carrier generating material into said body. CONSTITUTION:At least one kind of the azo compd. expressed by the formula I is incorporated as the carrier generating material into the above-mentioned body. In the formula, R1 denotes a hydrogen atom, alkyl group, alkoxy group, halogen atom, nitro group, cyano group or hydroxyl group, A is expressed by the formula II, R2 denotes a substd. or unsubstd. alkyl group, R4 denotes a substd. or unsubstd. aryl group, R5 denotes a substd. or unsubstd. alkyl group, aralkyl group or aryl group. The higher sensitivity and smaller residual potential are thereby obtd. and further, the efficiency of carrier generation is high; therefore, the electrophotographic sensitive body having a high copying speed is obtd. The fatigue deterioration by repetitive uses is decreased and the stable characteristics are maintained in various severe environments from low to high temps. and low to high humidities.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an electrophotographic photoreceptor, and more specifically, the present invention relates to an electrophotographic photoreceptor, and more specifically, a specific azo compound is coated on a conductive support as a carrier generating substance. By making it contain.

The present invention provides a novel electrophotographic photoreceptor having excellent photosensitivity and durability.

(Prior Art) The electrophotographic method has already been published by Carlson in US Patent No. 2.297.
As disclosed in No. 691, this photographic method is an ingenious combination of electrostatic and photoconductive phenomena, in which a photoconductive photoreceptor is exposed in the dark by corona discharge or the like.

An image forming method that uses photoconductivity to uniformly charge the surface and then convert the optical image into an electrostatic latent image, which is then converted into a visible image by attaching colored charged powder (toner) to it. There is one.

The basic electrical and photoelectric properties required of a photoreceptor in such electrophotography are that it can be charged to an appropriate potential in a dark place, that this potential can be maintained for an appropriate amount of time, and that it can be charged quickly by light irradiation. For example, the electric charge can be dissipated.

In such photoreceptors, amorphous selenium,
Inorganic photoconductive materials such as cadmium sulfide and zinc oxide have been widely used. Although these inorganic materials satisfy the above conditions, they also have some drawbacks. For example, cadmium sulfide or zinc oxide is used as a photoreceptor by dispersing it in a resin as a binder.

Smoothness, flexibility! 11! It has mechanical drawbacks such as hardness, tensile strength, and abrasion resistance, so it cannot withstand repeated use as it is. Furthermore, when using cadmium sulfide, it is necessary to consider hygiene and sanitary issues.

In addition, amorphous selenium must be manufactured by vapor deposition, which not only increases manufacturing cost but also has poor flexibility (and is difficult to process into a belt shape).
It has drawbacks such as the toxicity of selenium and its sensitivity to heat and mechanical shock, so care must be taken when handling it.

In recent years, in order to eliminate the drawbacks of these inorganic photoreceptors,
Research on organic photoreceptors is progressing, and organic photoreceptors.

Easy to form a film, easy to manufacture, lightweight.

Flexibility 2 Because it has many advantages of spectral sensitivity multifluidity 2
Various organic photoreceptors have been proposed, and some are in practical use.

For example, poly-N-vinylcarbazole and 2,4°7-
Photoreceptor consisting of dolinitrofluorene-9-one (U.S. Pat. No. 3,484,237), poly-N-vinylcarbazole sensitized with biryllium base dye (Japanese Patent Publication No. 48-25658), dye and a resin (Japanese Unexamined Patent Application Publication No. 47-10735).

Furthermore, electrophotographic photoreceptors have been proposed that combine a substance that generates carriers when exposed to light (called a carrier-generating substance) and a substance that can transport the generated carriers (called a carrier-transporting substance). . For example, U.S. Pat. No. 3.791.826 discloses a photoreceptor in which a carrier transport layer is provided on a carrier generation layer, and U.S. Pat. Photoreceptors have been described that have a photosensitive layer dispersed in a transport material. By assigning the functions of this type of carrier generation and carrier transport to separate substances, that is, by combining the carrier generation substance and the carrier transport substance, the characteristics can be improved and a useful photoreceptor can be provided. be done.

Up to now, many proposals have been made to use a Y-sazo compound as a carrier-generating substance in this type of photoreceptor.

For example, as a photoreceptor containing a J1' meazo compound in the photosensitive layer, JP-A-57-102629. Japanese Unexamined Patent Publication No. 57-
132159. JP-A-57-191644° JP-A-57
-176055. JP-A-58-147746 and the like are already known. However, these X-sazo compounds
Characteristics such as sensitivity, residual potential, and stability during repeated use are not always completely satisfactory.
Furthermore, the selection range of carrier transporting substances is also limited, and the reality is that nothing that completely satisfies the wide range of requirements of electrophotographic processes has yet to be found.

(Problems to be Solved by the Invention) The present invention provides an electrophotographic photoreceptor containing a specific azo compound that is excellent in sensitivity, repeatability, durability, and the like.

[Structure of the invention]

(Means for Solving the Problem) As a result of intensive research, the present inventors have discovered that an azo compound having a specific structure is a truly useful carrier-generating substance for electrophotographic photoreceptors. The present invention was completed by discovering that an electrophotographic photoreceptor using this carrier-generating substance has excellent properties.

Specifically, the present invention provides an electrophotographic photoreceptor having excellent properties using an azo compound having a novel structure.

An object of the present invention is to provide an electrophotographic photoreceptor that has high sensitivity and low residual potential by containing a novel carrier-generating substance, and further has high carrier generation efficiency and thus has a high copying speed. Another object of the present invention is that when used as a photoreceptor for repetitive transfer type electrophotography in which charging exposure, development, and transfer steps are repeated, fatigue deterioration due to repeated use is small, and furthermore, the present invention is more effective than low temperatures, high temperatures, and low humidity. An object of the present invention is to provide an electrophotographic photoreceptor with excellent durability and environmental resistance that maintains stable characteristics under various harsh environments such as high humidity. Further, among these electrophotographic photoreceptors, those having spectral sensitivity at 780 nm or more can also be provided as photoreceptors for printers using Ar laser, He-Ne laser, or semiconductor laser as a light source.

This object of the present invention is achieved by containing at least one azo compound represented by the following general formula (1) as a carrier generating substance.

At least one azo compound represented by the following general formula (1)
An electrophotographic photoreceptor characterized by having a photosensitive layer containing seeds.

(In the formula, R1 is a hydrogen atom, an alkyl group, an alkoxy group,
It represents a halogen atom, a nitro group, a cyan group, or a hydroxyl group, and n represents an integer of 2 to 3.

A is.

, R2 is a substituted or unsubstituted carbamoyl group,
R6 is a hydrogen atom, a substituted or unsubstituted alkyl group,
R4 represents a substituted or unsubstituted aryl group, and R5 represents a monosubstituted or unsubstituted alkyl group, aralkyl group, or aryl group.

Furthermore, to explain the substituents of A, R2 is a general formula of an unsubstituted alkyl group, an aralkyl group, an aryl group; R7 is a hydrogen atom, a substituted or unsubstituted alkyl group, an aromatic hydrocarbon group,
These substituents representing aromatic heterocyclic groups include alkyl groups, halogen atoms, and cyano groups.

It may have a substituent such as a nitro group, an alkoxy group, a carboxyl group, a carbamoyl group, an acyl group, an amino group, a dialkylamino group, a trifluoromethyl group, but is not limited to these substituents.

R is a hydrogen atom, a substituted or unsubstituted alkyl group.

The alkyl group has a halogen atom, a cyan group,
It may also have an amino group or the like.

R4 is a substituted or unsubstituted aryl group, and these substituents are also an alkyl group, a halogen atom, or a nitro group.

It may have a substituent such as a cyano group, an alkoxy group, an amino group, or a trifluoromethyl group.

R5 is a substituted or unsubstituted alkyl group or aralkyl group.

It represents an alkyl group, but these substituents also include an alkyl group,
It may have a substituent such as an alkoxy group, a halogen atom, a nitro group, a cyano group, an amino group, or a trifluoromethyl group, but is not limited to these substituents.

The azo compound represented by the general formula (1) has the general formula R,
n is a diamine or triamine shown in the same manner as in (1), which is tetrazotized or hexazated by a conventional method, and then mixed with various couplers with water, dimethylformamide, dimethyl sulfoxide,
It can be easily obtained by coupling in the presence of an alkali in other organic solvents. Also, borofluoride salts, tetrazonium salts or hexazonium salts of diamines or triamines.

Once isolated in the form of zinc chloride double salt, etc., cambling may be performed.During this diazotization and coupling reaction, some compounds may be mixed in which some of the amino groups in the compound remain unreacted. The electrophotographic properties will not be adversely affected even if

Next, typical examples of azo compounds used in the present invention will be explained.

The synthesis method is shown below.

Synthesis Example (Synthesis of Exemplified Compound (1)) 3.9-diaminobenzanthrone 25.9g (0°1
mol) in concentrated hydrochloric acid 21, cooled to below 5°C, and 13.8 g (0.2 mol) of sodium nitrite was added little by little. After the addition is complete, the mixture is stirred at 5° C. or lower for 1 hour, then 5 g of activated carbon is added, stirred for 10 minutes, and filtered. 250 g of ammonium hexafluorophosphate is added to the obtained filtrate, and the resulting crystals are filtered to obtain a hexafluorophosphate salt of a tetrazonium salt. This crystal is dissolved in N,N-dimethylformamide 51 to prepare a tetrazonium solution.

Next, 60 g (0.2 mol) of 2-hydroxy-3-(2-chlorophenylcarbamoyl)-naphthalene was added to N,N
- after dissolving in dimethylformamide 21.

Add 60 g of triethanolamine and dropwise add the above tetrazonium solution while stirring at 5° C. or below. After dripping.

After stirring at 20-30°C for 2 hours, the precipitated crystals were filtered, washed with N,N-dimethylformamide 21, washed with acetone and water, and dried to obtain compound (1).
) 64 g are obtained.

These compounds may be used alone or in combination of two or more.

The photoreceptor of the present invention contains a specific azo compound as a carrier generating substance as described above, and also contains various carrier transport substances, but it has various characteristics depending on how these specific azo compounds are applied. A photoreceptor of 100% is obtained.

For example, a structure usually referred to as a single-layer photoreceptor in which a carrier transport material is provided on a conductive support substrate in the same layer as a carrier-generating material, or a first layer mainly containing a carrier-generating material.

It can be used in a configuration commonly referred to as a laminated type photoreceptor, which is made by laminating two second layers mainly containing a carrier transporting substance on a conductive support substrate. These configurations are appropriately selected depending on the polarity of the photoreceptor used.

Carrier transport substances used in the present invention include, for example, hydrazones, pyrazolines, diarylalkanes, alkylene diamines, and triphenylamines.

Benzylanilines, diphenylbenzylamines.

Various compounds include, but are not limited to, triarylalkanes, oxadiazoles, oxazoles, stilbenes, and anthracenes. A more specific example is as follows.

Kabushi 2H5 2H5 Since the azo compound and carrier transport substance in the present invention do not have film-forming ability by themselves, a binder resin is used to form them as a photosensitive layer.

The binder preferably used in the present invention is a highly electrically insulating film-forming polymer or copolymer. These high molecular weight polymers and copolymers are 2
Binders preferably used in the present invention include phenolic resin, polyester resin, vinyl acetate resin, polycarbonate resin, polypeptide resin, cellulose resin, polyurethane resin, polyvinylpyrrolidone, polyethylene oxide, polyvinyl chloride resin, starch, and polyvinyl alcohol. .

Acrylic copolymer resin, vinyl chloride vinyl acetate copolymer resin, methacrylic copolymer resin, silicone resin.

Polyacrylonitrile copolymer resin, polyacrylamide, polyvinyl butyral, polyvinyl carbazole,
Examples include polyvinylidene chloride resin and silicone resin.

These polymer binders may be used alone or in combination of two or more, but the binders that can be used in the present invention are not limited to these. Further, in the photoreceptor of the present invention, a carrier generation layer containing a carrier generation substance as a main component is provided on the conductive support via an intermediate layer if necessary, and adjacent to the carrier generation layer the main component is a carrier transporting substance. A laminated structure including a carrier transport layer may also be used. Also, if such a laminated structure is used.

Which of the carrier generation layer and the carrier transport layer is to be used as the upper layer is determined depending on whether the chargeability is positive or negative. Generally, when negatively charged, it is advantageous in terms of characteristics to have a carrier transport layer as an upper layer. Further, in the photoreceptor of the present invention, there is a case where the photoreceptor has a laminated structure consisting of a carrier generation layer and a carrier transport layer, each of which is a separate layer.

The photosensitive layer is formed directly on the conductive support, or on top of an intermediate layer such as an adhesive layer or barrier layer provided as necessary, a carrier-generating substance is micronized in a dispersion solvent using a ball mill, an attritor, etc., as necessary. After coating the dispersion obtained by mixing and dispersing with a polymeric binder, the carrier transport substance and the polymeric binder are further mixed with dioxane, dichloromethane, or dichloroethane.

It can be made by coating a solution dissolved in an organic solvent such as tetrahydrofuran.

In the case of a II layer type photoreceptor, a carrier generating substance, a carrier transporting substance and a polymer binder are added to the same V1 solvent, and the coating liquid is dispersed using a ball mill, attritor, etc. and applied to the conductive support. It can be created by

9 The carrier transport substance used in the present invention is a binder 10
Preferably, the amount of carrier transport material is 10 to 300 parts by weight per part of Offi, although the present invention is not limited to this range. The thickness of the photosensitive layer is determined by the required photosensitivity and durability, and the mixing ratio of the carrier generating substance and the carrier transporting substance to the binder. The thickness of the photosensitive layer on the supporting conductive substrate is preferably 50 microns or less, preferably about 7 to 30 microns, from the viewpoint of film flexibility.

The photosensitive layer can also be coated with a layer that serves as a protective layer, if necessary.

The support used in the electrophotographic photoreceptor of the present invention includes:

Any material may be used as long as it is imparted with electrical conductivity, and any type of electrically conductive layer conventionally used may be used. Specifically, aluminum, sinus.

Fully flexible materials such as stainless steel, brass, and aluminum.

Examples include plastics in which indium oxide or tin oxide is deposited or laminated, or plastics in which conductive particles 1 such as carbon black, tin particles, or aluminum particles are dispersed. Also.

As for its shape, it may be sheet-like, cylinder-like, or other shapes.

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to the following examples. Hereinafter, in the examples, the compounds in the examples refer to the compounds added in the examples, and "parts" refer to parts by weight.

Example 1 Compound (1) 0.4
Polyester resin (Vylon 200) 0.
5 parts 1,2-dichloroethane 9.
5 parts or more of the composition was dispersed in a vibrating mill for 2 hours, and the resulting photoconductive composition was coated on an 80μ aluminum plate with a wire bar to a dry film thickness of 0.5μ.
A charge generation layer is formed by drying for 1 hour in an oven uniformly heated to 100°C. Next, a solution having the following composition was prepared so that the solution had a thickness of 15μ on the carrier generation layer.

Compound (a) Q
, 3-part polyester resin (Byron 200)
0.4 part dichloroethane
A layered photoreceptor was prepared by coating 2.6 parts with a wire bar and drying for 30 minutes in an oven uniformly heated to 80°C.

-5, OKV for the sample thus obtained.

Coronagi +7p 10 mm, 10 m/min
Corona discharge was applied at a charging speed of 10
5. With a tungsten light source at 2854 seconds later. OLu
Expose with x illuminance. The potential just before exposure at this time is 50%
The amount of light irradiation required to reduce the sensitivity was defined as the sensitivity. The sample measured in this way had a maximum surface charge of ff1-720.
V.

The dark decay rate was 2.4%, the sensitivity was 2.6 Lux, sec, and the residual potential was -16 ■.

Example 2 Compound (5) 0.4
Part acrylic resin (Dianal HR113) 0.
2-part vinyl chloride-vinyl acetate resin (VMCH)
0.2 parts ethyl acetate 1
4 parts or more of the composition was dispersed in a vibrating mill for 2 hours, and the resulting photoconductive composition was coated with a 5 μm thick aluminum foil and 75 μm thick.
A carrier-generating layer is formed by coating the laminate film with a polyester film of 0.5 μm using a wire bar so that the dry film thickness becomes 0.5 μm, and leaving it in an oven uniformly heated to 130° C. for 1 hour. Next, in Example 1, a laminated photoreceptor was prepared and tested in the same manner as in Example 1 using compound (r) in place of compound (a), and the maximum surface charge amount was -690V.

Dark decay rate 9.1%, sensitivity 2.2 Lux-sec,
, the residual potential was -16V.

Example 3 Compound (12) 1 part Compound (d) 2.5
part acrylic polyol (Takelac A-702) 3.6
Part: Epoxy resin (Epon 1007) 0.
5 parts methyl ethyl ketone 1.
2 parts cellosolve acetate 1.
Two or more parts of the composition are milled in a magnetic ball mill for 48 hours to obtain a photoconductive composition.

Next, this composition was placed on an 80μ aluminum plate to a dry film thickness of 8μ.
The photoreceptor was coated with a wire bar so that the photoreceptor was coated with a wire bar, and placed in an oven uniformly heated to 110° C. for 1 hour to obtain a single-layer photoreceptor. In this way, for the obtained sample, Example 1
The maximum surface charge amount was 560 V when measured as corona discharge +5.7 KV according to the above.

Dark decay rate 9.2%, sensitivity 3. I Lux-sec,
, the residual potential was 28 ■.

Example 4 The same procedure as in Example 1 was carried out, except that compound (3) was used instead of compound (1) and polycarbonate resin (Panlite L-1250) was used instead of polyester resin (Vylon 200). , a laminated photoreceptor was created. When the sample thus obtained was measured in the same manner as in Example 1, the maximum surface charge was 1-720cm, the dark decay rate was 10.2%, and the sensitivity was 2. I Lux・sec, +Residual potential -29V
Met.

Examples 5 to 16 The carrier-generating material and carrier-transporting material of Example 4 were replaced with the materials shown in the table below, and tests were conducted in the same manner.

It has excellent characteristics such as charge retention ability under conditions ranging from humidity to high humidity, environmental friendliness with respect to sensitivity changes, and durability.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer containing at least one azo compound represented by the following general formula [I] on a conductive support. General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc. A represents ▲There are mathematical formulas, chemical formulas, tables, etc.▼▲There are mathematical formulas, chemical formulas, tables, etc.▼▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, R_2 represents a substituted or unsubstituted carbamoyl group, R_3 represents a hydrogen atom, a substituted or unsubstituted alkyl group, R_4 represents a substituted or unsubstituted aryl group, R_5 represents a substituted or unsubstituted alkyl group, aralkyl group, or aryl group. 2. The photosensitive layer contains a carrier transporting substance and a carrier generating substance, and the carrier generating substance has the general formula [I
The electrophotographic photoreceptor according to claim 1, which is an azo compound represented by the following. 3. The photoreceptor 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.