JPH01247464A - Epsilon-form zinc phthalocyanine compound and electrophotographic photoreceptor prepared therefrom - Google Patents

Abstract

PURPOSE:To make it possible to improve the photographic sensitivity characteristics, wavelength characteristics, deterioration resistance, resistance to plate wear and image stability of an electrophotographic photoreceptor, by forming it so that it may give an X-ray diffraction pattern having specified X-ray diffraction peaks. CONSTITUTION:beta-Form zinc phthalocyanine is converted to the alpha-form by the acid basting process, acid slurry process or the like and the obtained alpha-form zinc phthalocyanine is optionally mixed with a grinding aid such as sodium chloride or Glauber's salt and converted to epsilon-form zinc phthalocyanine by mechanically grinding with a Banbury mixer, ball mill, homomixer or the like to obtain the title compound which can give an X-ray diffraction pattern having clear X-ray diffraction peaks in positions of Bragg angles (2theta+ or -0.2 deg.) of 7.6 deg., 9.2 deg., 11.3 deg., 15.3 deg., 16.9 deg., 17.5 deg., 20.5 deg., 21.0 deg., 21.4 deg., 23.1 deg., 26.0 deg., 27.4 deg. and 29.3 deg..

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention is an ε-type zinc phthalocyanine compound having a specific X-ray diffraction peak on an X-ray diffraction diagram, and furthermore, The present invention relates to the electrophotographic photoreceptor used.

(Conventional technology) Conventionally, selenium has been used as the photoreceptor for electrophotographic photoreceptors.

Inorganic photoconductors such as selenium alloys, zinc oxide, cadmium sulfide and tellurium have been used primarily. In recent years, the development of semiconductor lasers has been remarkable, and small and stable laser oscillators have become available at low cost and are beginning to be used as light sources for electrophotography. but,
Using semiconductor lasers that emit short-wavelength light in these devices has many problems in terms of lifespan, output, etc. Therefore, the conventionally used materials sensitive in the short wavelength region are unsuitable for use in semiconductor lasers, and the materials sensitive in the long wavelength region (
It has become necessary to research materials with high sensitivity to wavelengths of 780 nm and above. Recently, research has been actively conducted on multilayer organic photoreceptors using organic materials, especially phthalocyanine, which is expected to have sensitivity in the long wavelength region. For example, as a divalent metal phthalocyanine,
ε-type copper phthalocyanine (ε-CuPc), X-type metal-free phthalocyanine (X-H2Pc), and τ-type metal-free phthalocyanine (τ-H2Pc) have sensitivity in the long wavelength region. Trivalent and tetravalent metal phthalocyanines include chloroaluminum phthalocyanine (AfPccn) and chloroaluminum phthalocyanine chloride (Cj2AIl).
PcC1), or titanyl phthalocyanine (TiOP
c), chloroindium phthalocyanine (InPcC/
) is vapor-deposited and then brought into contact with the vapor of a soluble solvent to achieve long wavelengths and high sensitivity (Japanese Patent Application Laid-open Nos. 57-39484 and 1982-166959), T as a group Ⅰ metal.
A method of long-wavelength treatment of phthalocyanine containing i, Sn, and pb using various substituents, derivatives, or shifting agents such as crown ethers (Japanese Patent Application No. 59-362)
No. 54 and Japanese Patent Application No. 59-204045), sensitivity is obtained in the long wavelength region.

Furthermore, JP-A-57-148745 discloses tin.

Photoreceptors have also been reported in which a charge generation layer is made of a vapor-deposited film of metal phthalocyanine selected from metals such as aluminum, but these have extremely poor charging properties and are not practical.

JP-A-59-44053, JP-A-60-59354, and JP-A-60-260054 describe electrophotographic photoreceptors in which a charge generation layer is formed by vapor-depositing phthalocyanine having gallium in the central core. However, the charge ordering layer can only be used by vapor deposition, and further tests by the present inventors have revealed that the chargeability and dark decay properties, which are important requirements for electrophotographic properties, are extremely poor. However, it was not a practical electrophotographic photoreceptor.

As described above, there are still only a few practical charge-stopping materials that have high sensitivity in the oscillation wavelength region of semiconductor lasers, and the development of such materials is currently awaited.

LEDs have also been put into practical use as digital light sources for printers. LEDs in the visible light range are also used, but those that are generally put into practical use have an oscillation wavelength of 650 nm or more, typically 660 nm.

Azo compounds, perylene compounds, selenium, zinc oxide, etc.
Although it cannot be said that the phthalocyanine compound has sufficient photosensitivity at around 650 nm, it has an absorption peak around 650 nm, so it can be used as an effective material as a charge-generating material for LEDs.

(Problems to be Solved by the Invention) The present invention uses an ε-type zinc phthalocyanine compound, and in addition to excellent exposure sensitivity characteristics and wavelength characteristics, electrophotography has excellent deterioration resistance characteristics, stiffness resistance, and image stability during repeated use over a long period of time. The purpose is to obtain a photoreceptor.

[Structure of the invention]

(Means and effects for solving the problem) The Bragg angle (2θ±0.2°) of 7.6° on the X-ray diffraction diagram, 9.
2°, 11.3°, 15.3°, 16.9°, 17.5
°, 20.5 °, 21.0 °, 21.4 °, 23.1 °
, 26.0°, 27.4° and 29.3' positions.

Furthermore, an electrophotographic photoreceptor comprising a charge generating agent on a conductive support, wherein the charge generating agent is an ε-type zinc phthalocyanine compound and/or the conductive support. on the body.

An electrophotographic photoreceptor comprising a charge generation agent and a charge transfer agent, characterized in that the charge generation agent is an ε-type zinc phthalocyanine compound.

Furthermore, the ε-type zinc phthalocyanine compound of the present invention is as follows.

The benzene ring may have any substituent as long as it has a clear peak at the Bragg angle described above. Furthermore, the number of substituents is an integer of 0 to 4, and a mixture of two or more substituents and different numbers of substituents may be used.

The ε-type zinc phthalocyanine compounds of the present invention are broadly classified into two types.
It can be manufactured by various methods. The first method is to convert the synthesized β-type zinc phthalocyanine into the α-type using a method such as an acid pasting method or an acid slurry method, and then convert it into the ε-type using a mechanical grinding method. The second method is a method in which l-amino-3-iminoisoindolenine or phthalodinitrile, zinc or a zinc compound, and a metal phthalocyanine having a substituent are heated in an aprotic polar solvent.

The first method is described below.

Phthalocyanine can be produced by the phthalodinitrile method, in which phthalodinitrile and metal chloride are heated and melted or heated in the presence of an organic solvent; the Weiler method, in which phthalic anhydride is heated and melted with urea and metal chloride, or heated in the presence of an organic solvent; There are a method of reacting cyanobenzamide and a metal salt at a high temperature, and a method of reacting a dilithium phthalocyanine and a metal salt, but the methods are not limited to these. Examples of organic solvents include those with high boiling points that are inert to the reaction, such as α-chloronaphthalene, β-chloronaphthalene, α-methylnaphthalene, methoxynaphthalene, diphenylethane, ethylene glycol, dialkyl ether, quinoline, sulfolane, and dichlorobenzene. A solvent is preferred.

The zinc phthalocyanine used in the present invention is a phthalocyanine compound J (Mose
r and Thomas@Phthal.

Compounds obtained by known methods such as "cyanine compounds") and appropriate methods described above are used as acids, alkalis, acetone, methyl ethyl ketone.

Tetrahydrofuran, pyridine, quinoline, sulfolane, α-chloronaphthalene, toluene, dioxane, xylene, chloroform, carbon tetrachloride, dichloromethane, dichloroethane, trichloropropane.

Examples include a crystallization method, an extraction method such as Soxhlet, and a thermal suspension method using N,N'-dimethylacetamide, N-methylpyrrolidone, N,N'-dimethylformamide, etc. It is also possible to purify by sublimation.

The purification methods are not limited to these five. Since this compound is in the β form, acid pasting or acid slurry methods are best selected to convert it to the α form. Here, the acid pasting and acid slurry methods refer to a method in which a phthalocyanine compound is dissolved in sulfuric acid and then poured into 2 water to be reprecipitated.

The α-type zinc phthalocyanine compound obtained by the above method is transformed into the ε-type by mechanical grinding. Grinding may be done either dry or wet.

If necessary, it is also possible to use a grinding aid such as common salt or sulfur sulfate.

Equipment used during grinding includes a kneader, no-bury mixer, attritor, edge runner mill, roll mill, ball mill, sand mill, 5PEX mill, homomixer, disperser, agitator, show crusher, stamp mill, and cutter. Examples include, but are not limited to, mills and micronizers. In addition, by adding a phthalocyanine derivative having a substituent to phthalocyanine during mechanical grinding, more efficient ε
Can be transferred to a mold.

The second method is a very efficient method for producing ε-type phthalocyanine, in which zinc phthalocyanine is already produced in the ε-type crystal form during the synthesis of 9, and does not require any subsequent milling process. It can be said that the significance is extremely large.

The solvent is an aprotic polar solvent, preferably a boiling point of 100°C
Solvents having the above-mentioned properties include cellosolve acetate, dimethylformamide, dimethylsulfoxide, hexamethylphosphoramide, tetramethylurea, ethylene carbonate, propylene carbonate, α-butyrolactone, sulfolane, and diglyme.

Grime, dioxane, nitromethane, nitroethane,
Examples include 2-nitropropane, 1-morpholine, and the like.

The metals or compounds thereof to be used include, for example, zinc metal powder, oxides, chlorides, and sulfates thereof.

Examples include nitrates and acetates. The amount used is preferably 1/4 mole or more relative to phthalodinitrile and l-amino-3-iminoisoindolenine.

Further, the phthalocyanine derivative used in the present invention includes a metal phthalocyanine having a substituent on one or more of the four benzene nuclei of the phthalocyanine.

The charge generation layer using the ε-type zinc phthalocyanine compound prepared by the above method is a uniform layer with high light absorption efficiency. There are few gaps between the layer and the undercoat layer or the four-conductor substrate, even during repeated use.

It is possible to obtain an electrophotographic photoreceptor that satisfies many requirements, including characteristics as an electrophotographic photoreceptor such as potential stability and prevention of increase in bright area potential, reduction in single image defects, and printing durability.

An n-type photoreceptor is fabricated by laminating an undercoat layer, a charge generation layer, and a charge transfer layer in this order on a conductive substrate. In addition, the p-type photomaterial is one in which a charge transfer layer and a charge generation layer are laminated in this order on an undercoat layer, or a charge generation agent and, if necessary, a charge transfer agent are laminated on the undercoat layer together with a suitable resin. Some are made by dispersion coating. If necessary, an overcoat layer may be provided on both photoreceptors for surface protection and prevention of toner filming.

The ε-type zinc phthalocyanine compound of the present invention can be suitably used for all of the above-mentioned various photoreceptors. Also.

The charge generation layer can be obtained by dispersion coating an ε-type zinc phthalocyanine compound and a resin in a suitable solvent, but if necessary, it can also be used by dispersion coating without the resin.

The charge generation layer on the photoconductor is applied using a spin coater.

applicator, spray coater, bar coater.

Dip coater, doctor blade, roller coater,
This is carried out using a curtain coater or a bead coater, and drying is preferably carried out by heating at 40 to 200'C for 10 minutes to 6 hours under stationary or blowing air conditions. After drying, the film is coated to a thickness of 0.01 to 5 microns, preferably 0.1 to 1 micron.

The binder that can be used when forming the charge generation layer by coating can be selected from a wide variety of insulating resins.

It can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene. Preferably polyvinyl butyral,
Polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin, polyamide resin, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, silicone Examples include insulating resins such as resin, polystyrene, polyketone resin, polyvinyl chloride, vinyl chloride copolymer, polyvinyl acetal, polyacrylonitrile, phenol resin, melamine resin, casein, polyvinyl alcohol, and polyvinylpyrrolidone. The resin contained in the charge generation layer is suitably 100% by weight or less, preferably 40% by weight or less. Further, these resins may be used alone or in combination of two or more.

The solvent for dissolving these resins varies depending on the type of resin, and it is preferable to select a solvent that does not affect the charge generation layer and undercoat layer, which will be described later, during coating.

Specifically, aromatic hydrocarbons such as benzene, xylene, ligroin, monochlorobenzene, dichlorobenzene,
Ketones such as acetone, methyl ethyl ketone, and cyclohexanone, methanol, and ethanol.

Alcohols such as isopropanol, ethyl acetate.

Esters such as methyl cellosolve, carbon tetrachloride.

Chloroform, dichloromethane, dichloroethane.

Aliphatic halogenated hydrocarbons such as trichlorethylene 1 Ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether.

Amides such as N,N-dimethylformamide F°,N,N-dimethylacetamide, and sulfoxides such as dimethylsulfoxide are used.

The charge transfer layer is formed by dissolving and dispersing it in a charge transfer substance or a binder resin. The charge transfer agent used in the present photoreceptor may be any type of compound as long as it has the ability to transport charges.

Further, charge transfer substances can be used alone or in combination of two or more types. Resins used for the charge transfer layer include silicone resin, ketone resin, polymethyl methacrylate,
Polyvinyl chloride 1 acrylic resin, polyarylate, polyester, polycarbonate.

Polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-cyclodiene copolymer.

Insulating resins such as polyvinyl butyral, polyvinyl formal, polysulfone, polyacrylamide, polyamide, chlorinated rubber, poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, etc. are used.

Coating methods include spin coater and applicator.

Spray coater, bar coater, dip coater.

The coating is carried out using a doctor blade, roller coater, curtain coater, or bead coater, and the film thickness after drying is 5 to 50 microns, preferably 1 to 20 microns.

In addition to these layers, an undercoat layer can be provided on the conductive substrate for the purpose of preventing deterioration of chargeability, improving adhesion, and the like. As an undercoat layer, nylon 6, nylon 66, nylon 11. Nylon 51 Q, copolymerized nylon, polyamide such as alkoxymethylated nylon, casein, polyvinyl alcohol 1, nitrocellulose, ethylene-acrylic acid copolymer, gelatin, polyurethane,
Polyvinyl butyral and metal oxides such as aluminum oxide are used.

Further, conductive and dielectric particles such as metal oxides such as zinc oxide and titanium oxide, silicon nitride, silicon carbide, and carpon plug can be incorporated into the resin for adjustment.

The material of the present invention has an absorption peak at a wavelength of 800 parts 1 or more and 650 parts m, and can be used not only as an electrophotographic photoreceptor in copying machines and printers, but also in solar cells.

It is also suitable as an absorbing material for photoelectric conversion elements and optical disks.

(Example) Examples of the present invention will be specifically described below.

In the examples, part means 1 part by weight.

Examples 1-4 51.2 parts of phthalodinyl-IJ, 18.2 parts of anhydrous zinc acetate.
After heating and stirring 7 parts in 500 parts of quinoline at 210°C for 5 hours, the solvent was removed by steam distillation. Next.

Washing with acetone and filtration yielded 48.7 parts of zinc phthalocyanine crude. Figure 2 shows the X-ray diffraction pattern of this crude. 20 parts of this zinc phthalocyanine crude was dissolved little by little in 400 parts of 98% sulfuric acid at 5°C, and the mixture was slowly poured into 1,000 parts of ice water while keeping the temperature below 5°C for about 1 hour to precipitate. Filter the resulting crystals. The crystals were washed with distilled water until no acid remained, purified with acetone, and then dried to obtain 19 parts.

Using the α-type zinc phthalocyanine produced by the above method, ε-type zinc phthalocyanine was produced under the conditions shown in Table 1.

After confirming that the obtained sample has been transferred to ε-type zinc phthalocyanine by X-ray diffraction measurement, it is taken out from the apparatus and the solvent is removed.Then, the sample is washed in a 2% dilute sulfuric acid solution and filtered. I get angry.

The ε-type zinc phthalocyanine produced in Examples 1 to 4 is as follows.

XL? On the diffraction diagram, the Bragg angle (2θ±0.2@) is 7゜6゜, 9.2゜, 11.3@, 15.3
@, 16.9°, 17.5°, 20.5°, 21.0°, 21.4°, 23.1°, 2
Figure 1 shows an X-ray diffraction diagram of the ε-type zinc phthalocyanine of Example 1, which had distinct X-ray diffraction peaks at positions of 6.0°, 27.4°, and 29.3°.

Example 5 7.3 parts of 1-amino-3-iminoisoindolenine and 22 parts of cellosolve acetate were placed in a Yotsuro flask equipped with a stirring device, and heated to 60°C with stirring to form a solution. A solution obtained by heating 0.4 part of the following phthalocyanine derivative obtained by condensing zinc phthalocyanine, 2-pyrrolidone, and formaldehyde in concentrated sulfuric acid to 60° C. with 22 parts of cellosolve acetate is added to the above solution while stirring. After further adding 1.0 parts of zinc chloride, the mixture is heated to a temperature at which reflux begins. After reacting for 2 hours under heating under reflux, the mixture is cooled to room temperature and filtered. The mixture was then washed with methanol and water, boiled for 1 hour in 500 parts each of 2% hydrochloric acid and 2% aqueous sodium hydroxide solution, and then filtered.

By washing with water and drying, 6.7 parts of zinc phthalocyanine having an ε-type crystal form is obtained.

Next, a method for producing an electrophotographic photoreceptor using the ε-type zinc phthalocyanine of Examples 1 to 5 as a charge generating agent will be described.

Copolymerized nylon (Amiran CM-8000 manufactured by Toshi) 10
was mixed with 190 parts of ethanol in a ball mill for 3 hours, and the resulting coating liquid was applied onto a sheet of polyethylene terephthalate (PET) film with aluminum vapor-deposited using a wire bar, and then dried to a film thickness of 0.
A sheet with a 5 micron subbing layer was obtained.

After sufficiently pulverizing 2 parts of ε-type zinc phthalocyanine obtained in Examples 1 to 5, it was dispersed in a ball mill for 6 hours with a resin solution prepared by dissolving 1 part of polyvinyl butyral resin (BH-3 manufactured by Tanesui Kagaku Co., Ltd.) in 97 parts of THF. did.

After applying this dispersion onto the undercoat layer and drying it.

A 0.3 micron charge generation layer was formed.

Polycarbonate resin (Kijin Kasei @ Panlite L-1
250) was mixed and dissolved in 8 parts of methylene chloride. After applying this liquid onto the charge generation layer and drying it.

A 15 micron charge transport layer was formed and electrophotographic properties were measured.

The electrophotographic properties of the photoreceptor were measured by the following method.

Static mode 2. Corona charge is 1 at -5.2KV
The surface potential was irradiated with 5 Lux of white light or 1 μW of light adjusted to 780 parts m, and the white light half-reduction exposure sensitivity (El/2) was determined from the time when the amount of charge decreased to 1/2.

The results of electrophotographic properties are shown in Table 1.

As shown in Table 1, the photoreceptors of Examples 1 to 5 were chargeable.

Good sensitivity <1μJ/ca in the wavelength range of 780 parts m
It had a high sensitivity of 1 or more.

Comparative Example 1 An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the zinc phthalocyanine crude prepared in Example 1 was used as a charge generating agent, and its electrophotographic properties were measured.

Comparative Example 2 An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the α-type zinc phthalocyanine prepared in Example 1 was used as a charge generating agent, and its electrophotographic properties were measured.

The results are shown in Table 2.

Table 2 i As a result of Table 2, the α type and crude (β type) of zinc phthalocyanine are 10 (μJ/cat
) The sensitivity was as follows.

That is, the photoreceptors produced in Comparative Example 1.2 were those of Examples 1 to 2.
Compared to photoreceptor No. 4, the surface potential of No. 2 is extremely low.

The sensitivity was also significantly lower, making it impractical.

Therefore, by using the ε-type zinc phthalocyanine of the present invention as a charge generating agent, it was possible to obtain a photoreceptor with excellent electrophotographic properties such as surface potential and sensitivity.

C Effects of the Invention] According to the present invention, an electrophotographic photoreceptor having excellent exposure intensity characteristics and wavelength characteristics could be obtained.

[Brief explanation of the drawing]

FIG. 1 is an X-ray diffraction diagram of the ε-type zinc phthalocyanine of the present invention produced in Example 1, and FIG. 2 is an X-ray diffraction diagram of the β-type zinc phthalocyanine used in Comparative Example 1. FIG. 3 shows the IR spectra of the ε-type zinc phthalocyanine produced in Example 1.

Claims (1)

[Claims] 1. Bragg angles (2θ±0.2°) of 7.6°, 9.2°, 11.3°, 15.3°, 16. on the X-ray diffraction diagram.
9°, 17.5°, 20.5°, 21.0°, 21.4
°, 23.1 °, 26.0 °, 27.4 ° and 29.
An ε-type zinc phthalocyanine compound characterized by having a clear X-ray diffraction peak at a position of 3°. 2. An electrophotographic photoreceptor comprising a charge generating agent on a conductive support, wherein the charge generating agent is the ε-type zinc phthalocyanine compound according to claim 1. 3. An electrophotographic photoreceptor comprising a charge generating agent and a charge transfer agent on a conductive support, wherein the charge generating agent is the ε-type zinc phthalocyanine compound according to claim 1. Photoreceptor.