JPH0430172A - Manufacture of thin film and electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance uniformity and characteristics as a photosensitive body by heating a specified dispersion or solution to a specified temperature or higher. CONSTITUTION:A hydrophobic substance powder having an average particle diameter of <= 10mum, preferably, 1 - 0.01mum is dispersed or dissolved into an aqueous medium with a surfactant, except ferrocene, having an HLB value of 10.0 - 20.0, the obtained dispersion or solution is heated to >= 40 deg.C, and the thin film of the hydrophobic substance is formed on an aluminum substrate, and an electric charge generating material is used as the hydrophobic substance, thus permitting a thin uniform of the hydrophobic substance to be formed on a base metal, such as aluminum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a thin film and an electrophotographic photoreceptor, and more particularly, the present invention relates to a method for producing a thin film and an electrophotographic photoreceptor, and more specifically, the present invention relates to a method for producing a thin film and an electrophotographic photoreceptor, and more specifically, the present invention relates to a method for producing a thin film and an electrophotographic photoreceptor, and more specifically, The present invention relates to a method for efficiently manufacturing a uniform thin film by heating treatment, and a method for manufacturing an electrophotographic photoreceptor with excellent photosensitive characteristics by forming a charge generation layer on an aluminum substrate using this method.

[Prior art and problems to be solved by the invention] Conventionally, methods for manufacturing thin films of dyes, etc. include vacuum evaporation, thermal CVD, plasma CVD, and ultra-high vacuum (ion beam, molecular beam epitaxy) methods. .

The LB peritoneal cast method is known. However, since all of these methods require operations such as dissolving materials such as dyes in organic solvents or heating them, they have not been able to form thin films of hydrophobic substances that are sensitive to heat.

Micelle electrolysis methods for forming IITf14 of various hydrophobic organic substances are also known (Electrochemical Society (54th) Spring Conference F201) (1987). This micelle solution method can produce thin films of various hydrophobic substances, and is attracting attention as an industrially advantageous method. However, it is necessary to introduce a ferrocene group as a redox group, and synthesis of a surfactant having such a ferrocene group requires time and effort, and a simpler method has been desired. Furthermore, according to the principle of micellar electrolysis, an IL film can only be formed on the anode, so it has been extremely difficult to form a film on an aluminum electrode (cathode), which is dissolved by anodic polarization.

On the other hand, in the field of photosensitive materials, film formation on aluminum substrates is desired, and the development of a simple method for forming thin films on aluminum is expected.

Under these circumstances, in recent years, HLB values have increased from 10.0 to 20.
A dispersion or solution obtained by dispersing or solubilizing a hydrophobic substance powder with an average particle size of 10 μm or less in an aqueous medium using a surfactant (excluding ferrocene derivatives) of A method of forming the hydrophobic substance thin film has been proposed (Chem, Le
tt,, 1iii, 1137).

However, the thin film formed by this method does not necessarily have sufficient uniformity, and even when used as a photoreceptor for electrophotography, the photosensitive characteristics are insufficient and it is not suitable for practical use. Furthermore, this method naturally requires power, and the substrate must be a conductor. By applying the thin film obtained by the above method to a photoreceptor, better photosensitive characteristics were obtained than those obtained by the previous film forming method, but further improvements are required for practical use. Ta. In addition to such property improvements, the conventional thin film manufacturing technology based on micelle electrolysis requires complicated efforts such as electrode connection and power supply associated with the electrolytic operation during film formation.

The present inventors have discovered that in the film forming method using micellar electrolysis,
Remaining issues, such as whether electrolytic operation is essential, were investigated in more detail.

[Means to solve the problem]

As a result, a film can be formed on a substrate such as an aluminum plate by simply heating the dispersion or solution above 40°C, especially 40 to 90°C, and the uniformity of the resulting thin film and photoreceptor properties are dramatically improved. found that it improved. The present invention
It was completed based on this knowledge.

That is, the present invention involves dispersing or solubilizing a hydrophobic substance powder with an average particle size of 10 μm or less in an aqueous medium with a surfactant (excluding ferrocene derivatives) having an HLB value of 1000 to 20.0, and then dispersing the resulting dispersion. Or add the solution to 40
Heating above °C, the hydrophobic substance, i! The present invention provides a thin film manufacturing method characterized by forming a film. Furthermore, the present invention provides a charge generating layer (CGL) of an electrophotographic photoreceptor using an aluminum plate as a substrate and a charge generating substance (abbreviated as CGM) as a hydrophobic substance. The present invention provides a method for manufacturing an electrophotographic photoreceptor, characterized in that:

Hydrophobic substance powder is used as the object to be dispersed or solubilized in the method of the present invention, that is, as the raw material for the thin film.

This hydrophobic substance powder has an average particle diameter of 10 μm or less, preferably about 1 to 0.01 μm. If the average particle size exceeds 10 μm, various problems arise, such as it takes time to disperse and solubilize in an aqueous medium, and uniform dispersion and solubilization become difficult. The type of the hydrophobic substance powder may be appropriately selected depending on the use of the thin film to be formed, especially the use as an electrophotographic photoreceptor, and various types can be mentioned, regardless of whether it is an organic substance or an inorganic substance.
In the method for producing an electrophotographic photoreceptor of the present invention, it is particularly advantageous for the hydrophobic substance to be CGM. To give specific examples, examples of organic substances include phthalocyanine, metal complexes of phthalocyanine, and derivatives thereof (
For example, copper complexes, chloroaluminum complexes, vanadate complexes, chloroindium complexes, etc.), naphthalocyanine, metal complexes of naphthalocyanine and derivatives thereof,
Porphyrin, metal complexes of porphyrin and their derivatives, perylene, metal complexes of perylene and their derivatives, azo dyes, quinacridone, viologen, photomemory dyes such as sudan, and organic dyes, as well as 1,1°
-Diheptyl-4.4°-biviridinium dibromide.

Electrochromic materials such as 1,1''-didodecyl-4,4°-bipyridinium dibromide, 6-nitro-1,3,3-1-lynchylspiro (2°H-1°-
Examples include photosensitive materials (photochromic materials) such as benzobylane-2,2'-indoline (commonly known as spiropyran), optical sensor materials, and diazo type photosensitive materials such as 1-phenylazo-2-naphthol.

In addition, examples of inorganic substances include Ti0g, C, and CdS.

W 031 F e, o 3+ Y to 3+ Zr
Ot, A]zO3+ CuS.

ZnS, TaOx, LiNb0+, Si:+N4, etc.
Furthermore, there are various kinds of materials such as various superconducting oxides.

The surfactant used in the method of the present invention is other than a ferrocene derivative, and has an HLB value of 10.0 to 20.0. Preferably it is a 12-18 surfactant. non-ionic,
Both cationic and anionic surfactants can be used. Preferred examples of such surfactants include four toionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, polyoxyethylene alkylphenyl ether, and polyoxyethylene polyoxypropylene alkyl ether. Examples include alkyl sulfates, polyoxyethylene alkyl ether sulfates, alkyltrimethylammonium chlorides, and fatty acid diethylaminoethylamide.

In the present invention, first, the above-mentioned hydrophobic substance powder and surfactant are mixed into an aqueous medium. Examples of the aqueous medium include water, a mixture of water and alcohol, and a mixture of water and acetone.

The amount of surfactant added at this time is not particularly limited, but
Final concentration of 10 μM to IM, preferably 0.5 mM
It is selected to be in the range of ~5mM.

In the method of the invention, the mixture of the above surfactant, hydrophobe powder and aqueous medium is then subjected to ultrasound treatment.

Stir thoroughly using a homogenizer or a stirrer for about 1 hour to 7 days. During this stirring operation, HLB
By the action of the surfactant having a value of 10.0 to 20.0, the hydrophobic substance powder can be uniformly dispersed or solubilized in an aqueous medium to form a dispersion or an aqueous solution.

In the thin film manufacturing method of the present invention, a supporting salt can be added to the homogeneous dispersion or aqueous solution obtained as described above, if desired. If this supporting salt is not added, a highly pure thin film containing no supporting salt can be obtained, but this is determined depending on the film forming process and the situation of the obtained thin film. When a supporting salt is used, the type of the supporting salt is not particularly limited as long as it does not hinder the progress of solubilization or precipitation of the hydrophobic substance onto the substrate. Specifically, sulfates (salts of lithium, potassium, sodium, rubidium, aluminum, etc.) and acetates (lithium, potassium, sodium, etc.) are commonly used as supporting salts.

rubidium, beryllium, magnesium, calcium,
salts such as strontium, barium, aluminum),
Halide salts (lithium, potassium.

Sodium, rubidium, calcium, magnesium,
salts such as aluminum), water-soluble oxide salts (lithium,
potassium, sodium, rubidium.

salts of calcium, magnesium, aluminum, etc.) are preferred. The amount of this supporting salt to be added may be within a range that does not interfere with the precipitation of the hydrophobic substance that has been solubilized or dispersed, and is usually at a concentration of about θ to 300 times that of the above-mentioned surfactant.
Preferably, the concentration is about 10 to 200 times higher.

In addition, depending on the situation of a homogeneous dispersion or aqueous solution, excess hydrophobic substances are centrifuged and decanthisilane is used.

After removal by static sedimentation or the like, the substrate is immersed in the obtained liquid, and film formation is performed while it is left standing or without being slightly stirred. During the film forming process, the hydrophobic substance powder may be supplemented and added to the above homogeneous liquid, or a part of it may be extracted from the system, and the hydrophobic substance powder is added to the extracted liquid, thoroughly mixed and stirred, and then A circulation circuit for returning this liquid to the system may also be provided.

Various materials can be used as the substrate to be removed, but base metals, such as metals such as aluminum, zinc, tin, iron, nickel, and magnesium, and alloys such as stainless steel are preferable, and copper, platinum, and metal alloys are preferable. , silver, gray
Carbon, conductive metal oxides, organic polymer conductors, etc. and semiconductors such as crystalline silicon, amorphous silicon, etc. can also be used. In particular, it is suitable to use an aluminum substrate.

The film forming conditions in the method of the present invention may be set to conditions that produce a thin film of the hydrophobic substance on the substrate.Such conditions vary depending on the situation, but specifically, The temperature may be set at 40°C or higher, preferably in the range of 40 to 90°C.

It is also effective to further perform post-treatments on the thin film obtained by the method of the present invention, such as solvent washing and tenohake treatment at 100 to 300° C., if necessary.

In the present invention, the thin film of the hydrophobic substance obtained as described above is used as a CGL, and a charge transfer layer (
It is also possible to form a CTL (abbreviated as CTL). This CT
L can be produced by a barcode or spin code method. Further, examples of CTL materials include PVK, hydrazone, bistriphenylamine, and the like.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 Copper phthalocyanine (manufactured by Tokyo Kasei) in 250 cc of water.

Polyoxyethylene lauryl ether (manufactured by Kao ■).

(trade name: Br1j 35, HLB value 18.0) and lithium bromide were added to the solution at concentrations of 7 mM, 2 mM, and 0.1 M, respectively. This mixed solution was dispersed with ultrasonic waves for 30 minutes, and then stirred at room temperature all day and night. Further, the cell was allowed to stand for a day and night, after which 50 cc of the supernatant liquid was put into an electrolytic cell, an aluminum plate was inserted as a substrate, and the temperature of the cell was raised from room temperature to 90° C. to form a thin film.

Examples 2 to 5 In Example 1, the final temperature of the cell was 80°C,
The same operations as in Example 1 were performed except that the temperatures were 70°C, 60°C, and 50°C.

Example 6 The same operation as in Example 4 was performed except that lithium bromide was not added.

Comparative Examples 1 and 2 In Example 1, the final temperature of the cell was 20°C and 20°C, respectively.
All operations were performed in the same manner as in Example 1 except that the temperature was 30°C.

Examples 1 to 6 and Comparative Example 1 above. Table 1 shows the observation and measurement results of film formability, gloss 1 surface uniformity, absorption peak wavelength, and crystal system for each thin film obtained in step 2.

Example 7 The thin film formed in Example 1 was thoroughly washed with ethanol and then dried. This was used as a charge generation layer (CGL), and a chlorobenzene solution of polyvinyl carbazole (concentration 11% by weight) was spun on the CGL. cord, thickness 6
A charge transport layer (CTL) of ~8 μm was formed. In this way, a photoreceptor consisting of polyvinylcarbazole CTL/copper phthalocyanine CGL/aluminum electrode was produced.

The performance of this photoreceptor was evaluated using a 5P42B tester (manufactured by Kawaguchi Electric) as described below.

That is, corona discharge was applied to the photoreceptor at -7 kV for 30 seconds to negatively charge the surface of the photoreceptor.

At this time, the surface potential (Vd) is at a wavelength of 610 nm or 63 nm.
By irradiating 0nm light (output 5μW), half the value (Vd
/2), and find the amount of light (in seconds) during that time.
Light intensity x time (unit: μJ/d) was used as an index of the photoreceptor for light with a wavelength of 610 nm or 63 onm. Table 2 shows the results of this performance evaluation.

Examples 8 to 1I The same operation as in Example 6 was performed except that the thin films of Examples 2 to 5 were used as CGLs, respectively.

The performance evaluation results for each are shown in Table 2.

(The following is a blank space) [Effects of the Invention] As described above, according to the method of the present invention, a uniform thin film of a hydrophobic substance can be formed on base metals such as aluminum, and it can be applied to photosensitive materials, etc. became.

In addition, the method of the present invention can use commonly used surfactants, and furthermore, the method of the present invention can achieve uniform C of the desired material.
An electrophotographic photoreceptor having GL and good sensitivity can be manufactured easily and inexpensively, and has extremely high practical value.

Furthermore, the present invention provides a thin film production technology that can be formed simply by applying temperature, and by applying this thin film production technology, it is expected that the method of manufacturing electrophotographic photoreceptors will be significantly developed. be. Moreover, since the film can be formed without applying electricity, there is no need for an electrolytic device or extraction electrode, which simplifies the photoreceptor manufacturing process, making it possible to save energy and significantly reduce manufacturing costs. Furthermore, since it is possible to form a film on an insulating substrate, it actually becomes possible to form a thin film on a polymer substrate such as an optical memory disk.

Therefore, the electrophotographic photoreceptor obtained by the method of the present invention can copy images much more clearly than before in a copying machine, making it possible to shorten the copying time and save energy for the exposure light source. Further, in a laser printer as well, printing time can be similarly shortened and exposure light source energy can be saved.

The thin film and electrophotographic photoreceptor formed by the method of the present invention can be used not only in the above-mentioned copiers and laser printers, but also in electronic device elements (EL, sensors, solar cells, EC, LCD displays, etc.) that use aluminum as an electrode. It can be effectively used in a wide range of applications such as FDP display display electrodes), elements using functional thin films (optical memory disks, PHB elements, superconducting elements, second-order nonlinear optical elements, third-order nonlinear optical elements), etc.

Claims (3)

[Claims] (1) Dispersing or solubilizing a hydrophobic substance powder with an average particle size of 10 μm or less in an aqueous medium with a surfactant (excluding ferrocene derivatives) having an HLB value of 10.0 to 20.0,
A method for producing a thin film, comprising: heating the resulting dispersion or solution to 40° C. or higher to form the hydrophobic substance thin film on the substrate. (2) The method for producing a thin film according to claim 1, wherein the substrate is a base metal. (3) An electrophotographic photoreceptor characterized in that the thin film produced by the method of claim 1 using an aluminum plate as a substrate and a charge generating substance as a hydrophobic substance is used as a charge generation layer of the electrophotographic photoreceptor. manufacturing method.