JPH04130434A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body having a high sensitivity and less residual potentials by incorporating specific two kinds of hydrazone compds. as a charge transfer material into this photosensitive body. CONSTITUTION:The compds. expressed by formula I and formula II are incorporated into this photosensitive body. In the formula I, X denotes an oxygen atom, sulfur atom or imino group which may have a substitutent; A1, A2 denote an alkyl group, aralkyl group, etc.; A3, A4 denote a hydrogen atom, alkyl group, aralkyl group, etc.; n denotes 0 or 1 integer. In the formula II, B1, B2 denote an alkyl group, aralkyl group or aryl group; Y denotes an arom. hydrocarbon group or arom. heterocyclic group which may have a substitutent; m denotes 1 or 2. The electrophotographic sensitive body having the high sensitivity, the less residual potential and the image stability is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial Field of Application) The present invention relates to an electrophotographic photoreceptor, and more particularly, it relates to an electrophotographic photoreceptor, and more specifically, a photoconductive layer formed on a conductive support. S
By containing at least two kinds of hytrason compounds, an electrophotographic photoreceptor having excellent photosensitivity and durability is provided.

(Prior art) Electrophotography has already been published by Carlson in US Patent No. 2.2976.
As disclosed in No. 91, this photographic method cleverly combines electrostatic and photoconductive phenomena, and the surface of a photoconductive photoreceptor is uniformly charged by corona discharge in a dark place. After that, the optical image is converted into an electrostatic latent image using photoconductivity,
This is one of the image forming methods in which colored charged powder (toner) is attached to this to turn it into a visible image.

The basic electrical and photoelectric properties required of a photoreceptor in such electrophotography include being able to be charged to an appropriate potential in a dark place, being able to maintain this potential for an appropriate amount of time, and S. For example, the charge can be quickly dissipated by light irradiation.

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 and zinc oxide can be used as photoreceptors by dispersing them in a resin as a binder, but they do not have smoothness. , flexibility, hardness,
Because it has mechanical drawbacks such as tensile strength and friction resistance, it cannot withstand repeated use as it is.

Furthermore, when using cadmium sulfide, it is necessary to consider hygiene issues.

In addition, amorphous selenium must be manufactured by vapor deposition, which not only increases the manufacturing cost but also has no flexibility, making it difficult to form a heald shape, and the toxicity of selenium. It also has disadvantages such as being sensitive to heat and mechanical shock and requiring care when handling.

In recent years, in order to eliminate the drawbacks of these inorganic photoreceptors,
Research on organic photoreceptors has progressed, and organic photoreceptors have a wide variety of characteristics such as ease of film formation, ease of manufacture, light weight, flexibility, and Kerr light sensitivity. Some photoreceptors have been put into practical use.

Example Eva, poly-N-vinylcarbasol and 2.4.71
- IJ nitrofluoren-9-one photoreceptor (
U.S. Pat. No. 3,484,237), poly N-hinylcarhadur and pyrylium salt dyes (
(Japanese Patent Publication No. 48-25658), Photosensitivity whose main component is a eutectic complex consisting of a dye and a resin (* (Japanese Patent Publication No. 47-10)
', Publication No. 35).

Further, an electrophotographic photoreceptor has been proposed that combines a substance that generates electric charge when exposed to light (referred to as a charge-generating substance) and a substance that can transport the generated electric charge (referred to as a charge-transporting substance). For example, U.S. Patent No. 3,79L
No. 826 discloses a photoreceptor in which a charge transport layer is provided on a charge generation layer, and U.S. Pat. It also states which photoreceptor it has. By assigning the functions of this kind of charge generation and charge transport to different substances, that is, by combining the charge generation material and the charge transport material, the characteristics can be improved and a useful photoreceptor can be provided. be done.

Until now, many charge generating substances useful in this type of photoreceptor have been known. On the other hand, various materials have been proposed as charge transport materials, and at present, it is difficult to say that they are necessarily satisfactory. The basic properties of an excellent charge transport material are that when it is charged, it can hold a sufficient potential, and that it can sufficiently transmit light of an effective wavelength that allows the charge to be generated from the charge-generating material. Furthermore, it has the ability to quickly transport the charges generated by the charge generating substance. Also,
Practical requirements include the ability to form a uniform film either alone or dissolved in a binder, and to be able to withstand harsh environmental conditions such as temperature, humidity, and ozone and NOx generated during corona discharge. It is necessary that the electrostatic properties do not deteriorate or change. Until now, as this type of charge transport material, polyphenyl compounds such as triphenyl have been classified by chemical structural formula, and U.S. Patent No. 3.717.4
No. 62, U.S. Patent No. 4,150,987, Japanese Unexamined Patent Publication No. 1983
-52064, U.S. Pat. No. 3,820,989; diarylalkane compounds described therein, U.S. Pat. No. 3.1
2,5-His(
P-diethylaminophenyl)-13,4-oxacyazole, the birapurine compound described in US Pat. No. 3,837,851, and the like are relatively excellent charge transport substances that have been proposed in recent years. However, the current situation is that even these charge transport materials cannot be said to satisfy all of the above conditions.

(Problems to be Solved by the Invention) The present invention provides an electrophotographic photoreceptor having excellent sensitivity, repeatability, durability, and the like.

[Structure of the Invention j (Means for Solving the Problems) The present invention provides an electrophotographic photoreceptor having a photosensitive layer on a conductive support, which comprises a compound represented by the following formula CI''r and a general formula LHE. This is an electrophotographic photoreceptor containing one or more of the compounds shown above.

- Formula (1) is an imino group that may have a group. At and Az are each independently an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group. A: + and Aa are each independently a hydrogen atom , an alkyl group, an aralkyl group, an alkoxy group, or a halogen atom.Furthermore, A, and A3 or A2
and A4 may form an aliphatic heterocyclic residue. However, if both A1 and A2 are an alkyl group or A and A2 form a heterocyclic residue, this excludes the case where both A3 and A4 are hydrogen atoms. A is an alkyl group, an aralkyl group, an aryl group, or a heterocyclic residue.

A, , A, each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkyne group, an aryl group, an amino group, or an alkylamino group. A and A7 may form a naphthalene ring residue. n is an integer of 0 or 1. ) General formula (n) (However, in the formula, B+ and B2 are each independently an alkyl group, an aralkyl group, or an aryl group.

Y is an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent. B1 and B2 may form a heterocyclic residue. n is an integer of 1 or 2.

An object of the present invention is to provide an electrophotographic photoreceptor with high sensitivity and low residual potential by containing two specific types of hydrazone compounds as charge transport substances. Another object of the present invention is to reduce the deterioration of charging characteristics due to fatigue deterioration due to repeated use and memory phenomenon when used as a photoconductor for repetitive transfer type electrophotography in which charging, exposure, development, and transfer steps are repeated. Another object of the present invention is to provide an electrophotographic photoreceptor with excellent durability and environmental friendliness that maintains stable characteristics under various harsh environments from low to high temperatures and from low to high humidity.

The substituents of the hydrazone compound of the present invention - Formula CI) are explained in detail: W substituents At, Az, Aa, Aa
, As, Ah, and A, the alkyl group refers to substituents such as methyl group, ethyl group, linear or branched propyl group, butyl group, pentyl group, hexyl group, and stearyl group; is a benzyl group, a phenethyl group,
Substituents such as cinnamyl group, naphthylmethyl group, henzhydryl group; Aryl group refers to substituents such as phenyl group, naphthyl group, anthryl group; Alkoxy group refers to methoxy group, ethoxy group, butoxy group, hexyloxy group,
A substituent such as a benzyloxy group; a heterocyclic residue is a substituent such as a pyridyl group, an oxacylyl group, or a benzothiazolyl group (however, when A and A2 form a heterocyclic residue, a piperidino group or a morpholino group) substituents such as)
; An alkylamino group refers to a substituent such as an ethylamino group, a diethylamino group, or a dibutylamino group, respectively.

Furthermore, to explain in detail the substituents of the hydrazone compound of formula (II), among the substituents B+ and Bz, the alkyl group includes a methyl group, an ethyl group, a linear or branched prokyl group, a butyl group, Substituents such as pentyl group, hexynol group, stearyl group; Aralkyl group refers to substituents such as benzyl group, phenethyl group, cinnamyl group, naphthylmethyl group, benzhydryl group; Aryl group refers to substituents such as phenyl group, naphthyl group, anthryl group. Indicates radical-like substitution.

General formula (1) or [II] used in the present invention
The hydrazone compound represented by can be easily produced by a known method, and JP-A No. 60-247644 discloses a method for producing general formula (1), and JP-A No. 60-243659.
The publication describes a method for producing general formula (If).

Representative examples of the hydrazone compounds used in the present invention are listed below.

xHs The photoreceptor of the present invention contains a hydrazone compound represented by the general formula [I] or (I[), and photoreceptors with various characteristics can be obtained depending on how these hydrazone compounds are applied. For example, in the present invention, a hydrazone compound as a charge transporting substance is provided on a conductive support in the same layer as a charge generating substance, which is usually referred to as a single-layer photoreceptor, or a structure mainly containing a charge generating substance. A first layer that contains a charge transport material and a second layer that mainly contains a charge transport substance are laminated on a conductive support.
It can be used in a configuration commonly referred to as a laminated photoreceptor.

These configurations are appropriately selected depending on the polarity of the photoreceptor used. Furthermore, examples of charge generating substances used in the present invention include the following. Inorganic optical semiconductors such as selenium, selenium alloys, CdS, ZnO, CdSe, and amorphous silicon can also be used as inorganic compounds.
Preferably, an organic charge generating substance is used.

Existing charge generating substances include, for example, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azo dyes such as monoazo dyes and disazo dyes, indigo pigments, quinacridone pigments, indanthrene pigments, xanthine dyes, and benzene. imidazole pigment,
Dyes and pigments such as perylene pigments and squalic menane dyes, eutectic complexes formed from pyrylium salt dyes and polycarbonate resins, and charge transfer complexes formed from electron-donating substances such as polyvinylcarbazole and electron-accepting substances such as TNF, etc. However, it is particularly preferable to use phthalocyanine pigments.

Since the hydrazone compound in the present invention does not have film-forming ability by itself, a binder resin is used to form it as a photosensitive layer. Further, since charge generating substances cannot form a film by themselves except for polymeric resins such as polyvinyl carbazole, a binder may be used as necessary.

The binder preferably used in the present invention is a highly electrically insulating film-forming polymer or copolymer. Such high molecular polymers and copolymers,
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 pyrrolidone. Examples include alcohol, acrylic copolymer resin, methacrylic copolymer resin, silicone resin, polyacrylonitrile copolymer resin, polyacrylamide, polyvinyl butyral, polyvinyl alcohol, and polyvinylidene chloride 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 charge generation layer containing a charge generation substance as a main component is provided on the conductive support via an intermediate layer if necessary, and adjacent to the core layer, a charge generation layer containing a charge transport substance as a main component is provided. A laminated structure including a charge transport layer may also be used. In addition, in the case of such a laminated structure, which of the charge generation layer and the charge transport layer is to be 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 place the charge transport layer as an upper layer. In addition, when the photoreceptor of the present invention has a laminated structure consisting of separate layers of a charge generation layer and a charge transport layer, the charge generation layer is placed directly on the conductive support or, if necessary, on an adhesive layer. (A is to provide an intermediate layer such as a /N rear layer and then either ■ vacuum evaporate it, ■ apply a solution of a charge generating substance dissolved in a suitable solvent, or ■ apply a charge generating substance using a ball mill, attritor, etc. It can be provided by a method such as applying a dispersion obtained by micronizing the particles in a dispersion solvent and mixing and dispersing them with a polymeric binder if necessary.

The polymer used at this time)\The inder may be the same as that used for the charge transport layer).

Alternatively, it may be a single photosensitive layer comprising the hydrazone compound according to the present invention and a binder.

The charge transport material is preferably 10 to 300 parts by weight per 100 parts by weight of the binder, however, the present invention is not limited to this range. Also,
The thickness of this photosensitive layer is determined by the required photosensitivity and durability, and the mixing ratio of the charge generating substance and the charge transporting substance to the binder. The thickness of the photosensitive layer on the conductive support is 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 charge generation layer and charge transport layer of the electrophotographic photoreceptor of the present invention may also contain a known sensitizer. Furthermore, surfactants, plasticizers, antioxidants, ultraviolet absorbers, dispersion aids, anti-settling agents, and the like may be used as appropriate.

The support used in the electrophotographic photoreceptor of the present invention may be any material as long as it is imparted with electrical conductivity (any type of electrically conductive layer conventionally used may be used). Examples include metals such as aluminum, copper, stainless steel, and brass cast, plastics thinly coated or laminated with aluminum, indium oxide, tin oxide, etc., and conductive particles, such as plastics with dispersed carbon particles, tin particles, and aluminum particles. In addition, the shape may be sheet-like, cylindrical, or other shapes.When using the electrophotographic photoreceptor according to the present invention, the light source is usually a halogen lamp or the like. In addition, when the charge generating substance is phthalocyanine, the sensitivity is 750 parts m or more, so the gallium-aluminum-arsenic semiconductor laser (
It is also possible to use a laser beam with an oscillation wavelength of 780 nm.

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples. In the following examples, "parts" refer to parts by weight.

Example 1 3 parts of τ-type metal-free phthalocyanine, 3 parts of vinyl chloride-vinyl acetate copolymer resin (manufactured by Union Carbide, trade name VMCH), and 94 parts of tetrahydrofuran were added to the aluminum surface of a polyethylene terephthalate sheet (75 μm) on which aluminum was deposited. Tomoko applied the dispersion coating liquid for 2 hours with a ball mill, dried it at 100"C for 2 hours, and obtained 0.25
A charge generation layer of .mu.m was formed.

Next, a hydrazone compound [1)-(
1) 5 parts, (II)-(1) 5 parts and polyester resin (manufactured by Toyobo Co., Ltd., trade name)\Iron 200) 1
A solution obtained by dissolving 0 parts of the above solution in 100 parts of methylene chloride was applied onto the charge generation layer and dried to form a charge transport layer with a thickness of 15 μm.

The electrophotographic photoreceptor prepared above was corona charged at -5.4 KV using Kawaguchi Electric's electrostatic copying paper tester 5P-428, and the amount of charge was reduced to 1/2 by irradiating the surface potential and 51 ux white light. From the time to white light half-exposure sensitivity (
E 1/2 ) was investigated.

Next, this photoreceptor was attached to the drum of an electrophotographic copying machine having a corona charger, an exposure section, a transfer charging section, a static eliminating exposure section, and a cleaner. The dark potential of this copying machine was set to -650V, the light potential to -150V, and the
The sheets were subjected to a repeated durability test, and the resulting images were evaluated in five grades based on the following criteria.

◎ Very good ○ Good △ Fair × Bad × × Very bad Examples 2 to 4 A photoreceptor was produced in the same manner as in Example 1 except that the hydrazone compound shown in Table 1 was used as the charge transport material. did.

Table 1 Comparative Examples 1 to 4 Hydrazone compound 1 shown in Table 2 as a charge transport substance
A photoreceptor was produced in the same manner as in Example 1, except that the seed IO portion was used.

Table 2 The results are shown in Table 3.

11!3 table 〔Effect of the invention〕 The present invention provides high sensitivity and low residual potential. An electrophotographic photoreceptor having image stability was obtained.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, each of a compound represented by the following general formula [I] and a compound represented by the general formula [II]. An electrophotographic photoreceptor characterized by containing at least one species. General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, in the formula, , an aralkyl group, an aryl group, or a heterocyclic group. A_3 and A_4 are each independently a hydrogen atom, an alkyl group, an aralkyl group, an alkoxy group, or a halogen atom. Furthermore, A_1 and A_3 or A_2 and A_4 are an aliphatic heterocyclic group. A residue may be formed.However, if A_1 and A_2 are both alkyl groups or A_1 and A_2 form a heterocyclic residue, this excludes the case where A_3 and A_4 are both hydrogen atoms.A_5 is an alkyl group. group, aralkyl group, aryl group, or heterocyclic group. A_6 and A_7 each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group,
It is an aryl group, an amino group or an alkylamino group. A_6 and A_7 may form a naphthalene ring residue. n is an integer of 0 or 1. ) General formula [II] ▲ Numerical formulas, chemical formulas, tables, etc.▼ (However, in the formula, B_1 and B_2 are each independently an alkyl group, an aralkyl group, or an aryl group. Y may have a substituent. It is an aromatic hydrocarbon group or an aromatic heterocyclic group. B_1 and B_2 may form a heterocyclic residue. m is an integer of 1 or 2.)