JPS60243660A - Photosensitive body - Google Patents

Abstract

PURPOSE:To improve the change of sensitivity and the change of the charged voltage during repeated use and to permit its use for high speed copy by incorporating a specified hydrazone compd. and a benzoic acid deriv. to a phthalocyanine photosensitive layer. CONSTITUTION:A hydrazone compd. expressed by the formula (wherein R1 is H, methyl, phenyl; R2 and R3 are alkyl, aryl, etc. or may form a ring together; (A) is an arom. group; n is 1 or 2) is used in combination with a benzoic acid deriv. substituted with a nitro group or a halogen atom in the nucleus in a photosensitive body contg. a phthalocyanine (Pc) photoelectric material dispersed in a binder. A non-metallic Pc or Cu phthalocyanine is used as the photoelectric material. The photosensitive body is used not only by forming a single layer on a substrate but also in the form of a function separating type by incorporating the hydrazone compd. and the benzoic acid deriv. together with Pc in a charge generating layer. By the use of such hydrazone compd., generation of induction effect is inhibited and the sensitivity and the gradation characteristic are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a photoreceptor having a photosensitive layer comprising particles of a phthalocyanine-based photoconductive material dispersed in a binder made of an insulating polymeric material.

Conventional technology In general, in electrophotography, the surface of the photosensitive layer of a photoreceptor is charged and exposed to form an electrostatic latent image, which is developed with a developer to make it visible, and the visible image is directly transferred onto the photoreceptor. There is a so-called PPC method, in which the visible image on the photoreceptor is transferred onto a transfer paper such as paper and the transferred image is fixed to obtain a copied image.

Conventionally, inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been known as photoconductive materials for forming the photosensitive layer of electrophotographic photoreceptors used for this type of purpose. These photoconductive materials have many advantages, such as being able to be charged to an appropriate potential in the dark, having little charge dissipation in the dark, or being able to quickly dissipate the charge when irradiated with light. On the other hand, it has various drawbacks. For example, selenium-based photoreceptors are difficult to manufacture because they require vapor deposition on a conductive support, and they easily crystallize due to factors such as temperature, humidity, and pressure, especially when the ambient temperature exceeds 40°C. However, there are disadvantages such as a significant change in charging properties and deterioration in image quality.

Cadmium sulfide photoreceptors do not have stable sensitivity in humid environments, and zinc oxide photoreceptors require the sensitizing effect of sensitizing dyes such as rose bengal. The sensitizing dye has the disadvantage that it cannot provide stable images over a long period of time because it causes charging deterioration due to corona charging and photofading due to exposure.

On the other hand, various organic photoconductive polymers such as polyvinylcarbazole have been proposed, but these polymers are superior to the above-mentioned inorganic photoconductive materials in terms of film formability and light weight. However, they are still inferior to inorganic photoconductive materials in terms of sufficient sensitivity, durability, and stability against environmental changes.

Various research and developments have been conducted to solve these drawbacks and problems, but in recent years, for example, Japanese Patent Application Laid-Open No. 50-38543
No. 1, JP-A-51-95852, JP-A-53-
Photoreceptors using phthalonanine-based photoconductive materials have been proposed in Japanese Patent Laid-Open No. 64040, Japanese Patent Application Laid-open No. 83744/1983, and the like.

Conventionally, photoreceptors made by dispersing phthalocyanine photoconductors in an electrically insulating resin medium are widely known in the field of electrophotography, and trinitroanthracene, trinitroanthracene, 2.4.7-Polycyclic or heterocyclic nitro compounds such as trinitrofluorenone; acid anhydrides such as phthalic anhydride and trimellidic anhydride; quinones such as anthracene; aromatic amines such as tetramethyl-P-phenylenediamine; Nitrile compounds such as cyanoethylene were known. By adding chemical sensitizers,
It is also known that an improvement in the sensitivity expressed based on the half-decreased exposure amount of the electrophotographic photoreceptor can be expected.

However, when an electrophotographic photoreceptor is used repeatedly and continuously, there is a drawback that, regardless of the presence of a sensitizer, the charging potential due to corona discharge or the like decreases from the initial charging potential upon repeated use.

In addition, photoreceptors with phthalocyanine-based photoconductive materials dispersed in a binder resin exhibit a so-called induction effect in which traps occur and there is a time lag (delay) from exposure to potential decay, making them unsuitable for high-speed copying. do not have.

The present invention has been made in view of the above facts, and its object is to change the sensitivity during repeated use of a photoreceptor having a photosensitive layer formed by dispersing a phthalocyanine-based photoconductive material in a binder. The object of the present invention is to improve the changes in charging potential and to make it possible to cope with high-speed copying.

SUMMARY OF THE INVENTION The gist of the present invention is to provide a photoreceptor having a photosensitive layer formed by dispersing a phthalonanine-based photoconductive material in a binder resin,
The above object is achieved by containing a hydrazone compound represented by the following general formula CI] and a benzoic acid derivative whose nucleus is substituted with at least one group or atom selected from the group consisting of a nitro group and a halogen atom. It is.

p.

As the phthalocyanine-based photoconductive material used in the present invention, any of the phthalocyanines and their derivatives known per se can be used. Specifically, aluminum phthalocyanine, vanadium phthalonanine, tin phthalocyanine, antimony phthalonanine, barium phthalocyanine, etc. Phthalocyanine, beryllium phthalocyanine, vanadium phthalocyanine, cobalt phthalocyanine, cobalt chlorophthalocyanine, copper-4-aminophthalocyanine, copper-4-chlorophthalocyanine, copper phthalocyanine, dysprosium phthalocyanine, germanium phthalocyanine, holmium phthalocyanine, iron phthalocyanine, iron polyhalophthalocyanine, lead Metal phthalocyanines such as phthalocyanine, lead polychlorophthalocyanine, cobalt hexaphenyl phthalocyanine, platinum phthalocyanine, and zinc phthalocyanine; metal-free phthalocyanine compounds such as dialkylaminophthalonanine, tetraazophthalocyanine, tetramethyl phthalocyanine, and tetraphenyl phthalocyanine are suitable. These can be used alone or in combination.

Further, a phthalocyanine derivative in which the hydrogen atom of the benzene nucleus in the phthalocyanine molecule is substituted with at least one electron-withdrawing group selected from the group consisting of a nitro group, a cyano group, a halogen atom, a sulfone group, and a carboxyl group;
A phthalocyanine-based photoconductive material composition obtained by mixing phthalocyanine and at least one unsubstituted phthalocyanine compound selected from the above-mentioned phthalocyanine compounds with an inorganic acid capable of forming a salt with them, and precipitating the mixture with water or a basic substance. You can also use objects. In this case, the electron-withdrawing group-substituted phthalocyanine derivative can be any one having 1 to 16 substituents in the molecule, and the electron-withdrawing group-substituted phthalocyanine derivative and other unsubstituted phthalocyanine compounds can be used. The composition ratio is such that the number of substituents of the former is 0001 to 2, preferably 0002 per molecule of phthalocyanine unit in the composition.
It is preferable to set the number to 1. Inorganic acids that can form salts with phthalocyanine compounds that can be used in producing the phthalocyanine-based photoconductive material composition include sulfuric acid, orthophosphoric acid, chlorosulfonic acid, hydrochloric acid,
Examples include hydroiodic acid, hydrofluoric acid, and hydrobromic acid.

Among the photoconductive materials mentioned above, those particularly suitable for achieving the object of the present invention include metal-free phthalonanine, copper phthalocyanine and derivatives thereof, such as thermoplastics known per se that are electrically insulating. All binders such as resins, thermosetting resins, photocurable resins, and photoconductive resins can be used. Examples of suitable binder resins include, but are not limited to, saturated polyester resins, polyamide resins, acrylic resins, ethylene-vinyl acetate copolymers, ionically crosslinked olefin copolymers (ionomers), styrene- butadiene block copolymer, polycarbonate, vinyl chloride-vinyl acetate copolymer, cellulose nysdel,
Thermoplastic binders such as polyimide: Thermosetting binders such as epoxy resins, urethane resins, silicone resins, phenol resins, melamine resins, xylene resins, alkyd resins, thermosetting acrylic resins; Photocurable resins; - Photoconductive resins such as N-vinylcarbazole, polyvinylpyrene, and polyvinylanthracene.

When these electrically insulating resins are measured individually, I
14Ω・m, JF's right male r-husband is preferable.

Regarding the blending ratio of the phthalocyanine-based photoconductive material and the binder, as the former increases, sensitivity improves, but dark decay increases significantly and charge retention becomes difficult.
On the one hand, it becomes less practical, and on the other hand, when the amount of the former decreases,
Dark decay is reduced or sensitivity is reduced, so the amount of photoconductive material is 5 to 100 parts by weight per 100 parts by weight of binder;
The amount is preferably 10 to 60 parts by weight.

The above-mentioned phthalocyanine-based photoconductive material is formed by dispersing it in a binder and coating it on a conductive support, but the photoreceptor thus obtained exhibits the indakunyong effect and is insufficient in terms of photosensitivity. It is. Accordingly, in the present invention, the photosensitive layer contains the hydrazone compound represented by the general formula [+1].

Specific examples of this hydrazone compound include (see blank below) C2H5 A photoreceptor containing the above hydrazone compound in a photosensitive layer formed by dispersing phthalocyanine-based photoconductive powder in a binder resin also has an induction effect. In addition, it has high sensitivity and good gradation. However, on the contrary, it was found that the dark decay rate was fast, the charging ability was low, and the repetition stability was lacking. Furthermore, when a large amount of a hydrazone compound was added, there was a problem that the sensitivity decreased with repeated use.

Therefore, in the present invention, in addition to the above hydrazone compound, a small amount of a benzoic acid derivative whose nucleus is substituted with at least one group or atom selected from the group consisting of a nitro group and a halogen atom is used in combination. This prevents and improves sensitivity changes and stabilizes repeatability.

It is generally known that when a small amount of an electron-accepting substance is added to a hydrazone compound, which is an electron-donating substance, the sensitivity decreases. However, as in the present invention, sensitivity and sensitivity can be improved by adding a small amount of a hydrazone compound represented by the general formula CI and a benzoic acid derivative whose nucleus is substituted with at least one group or atom selected from the group consisting of a nitro group and a halogen atom. It is surprising that the repeatability is improved.

Specific examples of benzoic acid derivatives whose nucleus is substituted with at least one group or atom selected from the group consisting of a nitro group and a halogen atom used in the present invention include P-nitrobenzoic acid, m-nitrobenzoic acid, P-nitrobenzoic acid, and P-nitrobenzoic acid. -Nitrobenzoic acid chloride, m-nitrobenzoic acid chloride, 3.5-dinitrobenzoic acid, 24-dinitrobenzoic acid, 34-dinitrobenzoic acid, 25-dinitrobenzoic acid, 24-dichlorobenzoic acid, 35-dinitrobenzoic acid Examples include chloride and methyl P-nitrobenzoate.

The amounts of the hydrazone compound and benzoic acid derivative added in the present invention are as follows:
30 to 700 parts by weight per 0 parts by weight, preferably 50 to 4 parts by weight
00 parts by weight, and the benzoic acid derivative is preferably used in an amount of 01 to 20 parts by weight, preferably 1 to 10 parts by weight. That is, if the amount of the hydrazone compound is less than the above range, the sensitivity will deteriorate, and if it is too large, the printing durability will deteriorate. Furthermore, if the amount of the benzoic acid derivative is too small, the effect will not be obvious, and if it is too large, the dark decay rate will increase and the charge retention ability will deteriorate.

In addition to the above-mentioned phthalocyanine-based photoconductive powder, resin, hydrazone compound, and benzoic acid derivative, the photoreceptor of the present invention may optionally contain any known additives or compounding agents. For example, examples of such compounding agents include antioxidants, ultraviolet inhibitors, thickeners, leveling agents, etc., which are known per se. Moreover, two or more types of hydrazone compounds may be used in combination, and electron-donating compounds such as pyrazoline compounds and triphenylmethane compounds may be added.

The photoreceptor of the present invention can be prepared by dissolving the above-mentioned hydrashiso compound and benzoic acid derivative together with a phthalocyanine-based photoconductive material and a binder resin in an appropriate solvent, applying the coating solution onto a conductive support, and drying it. It can be manufactured by forming a photosensitive layer with a thickness of usually 6 to 30 microns.

The photoreceptor is not limited to one in which the photosensitive layer is formed as a single layer on the support as described above, but may be one in which a charge generation layer and a charge transport layer are sequentially laminated on the support. In this case, the hydrazone compound and the benzoic acid derivative are contained in a charge generation layer formed by dispersing phthalocyanine in a binder resin.

Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 4.0 parts by weight of copper phthalocyanine and 02 parts by weight of tetranitrocopper phthalocyanine are dissolved in 500 parts by weight of 98% concentrated sulfuric acid with thorough stirring. The dissolved solution was poured into 2000 parts by weight of water to precipitate a composition of copper phthalocyanine and tetranitrocopper phthalocyanine. This composition is passed through the mouth, washed with water, and dried at 120'C under reduced pressure. Next, this composition 10
Weight part: thermosetting acrylic resin Acrydic A 40
5 (manufactured by Dainippon Ink) 225 parts by weight, melamine resin Super Beckamine J 820 (manufactured by Dainippon Ink) 75 parts by weight, P-dimethylaminobenzaldehyde diphenylhydrazone 15 parts by weight, 1 part by weight of 35 dinitrobenzoic acid o methyl isobutyl ketone ; Cellosolve acetate (
A photoconductive coating material was prepared by putting the mixture into a ball mill pot with 70 parts by weight of 1:1) and kneading it for 48 hours.The coating material was coated on an aluminum substrate to a thickness of about 15 .mu.m to prepare a photoreceptor.

Example 2.3 A photoreceptor was prepared in the same manner as in Example 1 except that the amount of 35 dinitrobenzoic acid in the formulation of Example 1 was changed to 03 parts by weight and 05 parts by weight, respectively.

Example 4 15 parts by weight of the composition obtained in Example 1 and polycarboy.
-35 parts by weight of polyester resin, 15 parts by weight of acrylic resin and 45 parts by weight of hydrazone compound example (6)
t parts, P-nitrobenzoic acid chloride 02 parts by weight and tetrahydrofuran:toluene (9:1) as a solvent.
A photoconductive paint was prepared by adding a mixed solvent to the mixture and kneading it in a ball mill pot for 48 hours. This paint was coated on an aluminum substrate to a thickness of about 15 μm to prepare a photoreceptor.

Example 5 15 parts by weight of the composition obtained in Example 1 and a polymer and bone.

35 parts by weight of polyester resin, 30 parts by weight of hydrazone compound example (3), 35 parts by weight of polyester resin, 30 parts by weight of hydrazone compound example (3),
10) Add a mixed solvent of tetrahydrofuran and toluene (9:1) as a solvent together with 15 parts by weight and 01 parts by weight of 35-dinitrobenzoic acid chloride, place the mixture in a ball mill pot, and knead for 48 hours to prepare a photoconductive paint. This paint was applied onto an aluminum substrate to a thickness of approximately 15 μm to produce a photoreceptor.

Composition obtained in Example 1 - 110 parts by weight, thermosetting acrylic resin Acrydic A405 22.5 parts by weight, melamine resin Super Beckamine J8207.5 parts by weight,
15 parts by weight of P-diethylaminobenzaldehyde phenylhydrazone (Compound Example (1)) was mixed with 70 parts by weight of a mixed solvent of methyl isobutyl ketone and cellosolve acetate (1:1).
A photoconductive coating material was prepared by putting it together with parts by weight in a ball mill pot and kneading it for 48 hours.The coating material was coated on an aluminum substrate to a thickness of about 15 .mu.m to prepare a photoreceptor.

15 parts by weight of the composition obtained in Example 1, 35 parts by weight of polycarbonate, 35 parts by weight of polyester resin, 15 parts by weight of acrylic resin, 45 parts by weight of hydrazone compound example (6), and 1 part by weight of tetrahydrofuran 1 toluene (9:1) as a solvent.
) and kneaded in a ball mill pot for 48 hours to prepare a photoconductive paint. This paint was coated on an aluminum substrate to a thickness of about 15 μm to prepare a photoreceptor.

Comparative Example 3 15 parts by weight of the composition obtained in Example 1, 35 parts by weight of polycarbonate, 50 parts by weight of polyester resin, 30 parts by weight of hydrazone compound example (3), hydrazone compound example (1)
0) Add 15 parts by weight of a mixed solvent of tetrahydrofuran and toluene (9:1) as a solvent, put it in a ball mill pot, and knead for 48 hours to prepare a photoconductive paint. A photoreceptor was prepared by applying the following coating.

Example 6 10 parts by weight of ε-type copper phthalocyanine, 20 parts by weight of hydrazone compound example (11), 36 parts by weight of acrylic polyol Acrydic A301 (manufactured by Dainippon Ink), Hanawa, 4 02 parts by weight of dinitrobenzoic acid, methyl isobutyl ketone;
The mixture was placed in a ball mill pot with 50 parts by weight of a mixed solvent of cellosolve acetate (1:1) and kneaded for 48 hours, and this paint was coated on an aluminum substrate to a thickness of about 15 μm to prepare a photoreceptor.

Comparative Example 4 A photoreceptor was produced in the same manner as in Example 6 except that 24-dinitrobenzoic acid was not added to the formulation of Example 6.

Comparative Example 5 A photoreceptor was produced in exactly the same manner as in Example 6 except that 25-dichlorobenzoquinone was added in place of 2.4 dinitrobenzoic acid in the formulation of Example 6.

The obtained photoreceptor was assembled into a commercially available powder image transfer type electrophotographic copying machine (EP-4502 manufactured by Minolta Camera), and +6
．． The surface potential of the photoreceptor immediately after being applied to the surface of the photoreceptor Vo (V) with a 5KV corona discharge, the decay rate of the surface potential after discharging for 1 second in the dark DDR, (%), and the surface potential after exposure are the initial surface The exposure amount E 1/2 (tux-sec) required to reduce the potential to 1/2, and Vo (V) and E 1/2 when 3000 copies were repeatedly made were measured. The results are shown in Table 1 below.

Table 1 As is clear from the results in Table 1, the photoreceptor of the present invention has the following properties:
This photoreceptor has superior electrostatic properties and sensitivity compared to those of comparative examples, and exhibits excellent properties for general copiers and laser printers.

Applicant: Minolta Camera Co., Ltd.

Claims (1)

[Claims] 1. A photoreceptor having a photosensitive layer formed by dispersing a phthalocyanine-based photoconductive material in a binder, which has the following general formula C:
A photoreceptor comprising a hydrazone compound represented by [I] and a benzoic acid derivative whose nucleus is substituted with at least one group or atom selected from the group consisting of a nitro group and a halogen atom. 1 May be bent to form a ring. 1 2. The photoreceptor according to claim 1, wherein the photoconductive material is metal-free phthalonanine or copper phthalocyanine.