JPH05281763A - Production of photosensitive body - Google Patents

Abstract

PURPOSE:To obtain a uniform photosensitive body material thin film which is restrained pH variation by dispersing a photosensitive body material in an aqueous medium incorporating a pH buffer agent with a surfactant, solubilizing it and forming the photosensitive body material thin film on an electrically conductive base plate. CONSTITUTION:Polyoxyethylene dodecylether, which is a nonionic surfactant, as the surfactant, and lithium bromide as an electrolyte are added to ion- exchanged water so as to be respectively the specified concentrations and besides a boric acid, which is a pH buffer agent, is added, and then the pH is adjusted at the specified value with NaOH. Next beta type copper phthalocyanine, which is a photosensitive body material, is added to the solution and after stirred, ultrasonic wave is applied for a specific hour to prepare a photosensitive body material dispersion solution and it is left standing for 24 hours and supernatant liquid is fractionated to be defined as testing liquid 1. The testing liquid 1 is kept at 60 deg.C in a constant temp. hot water bath 5 and an Al base plate 2 is put in it and a cathode is energized by using a galvanostat 6 to from the photosensitive body thin film on the Al base plate 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a photoconductor used in electrophotography and the like.

[0002]

2. Description of the Related Art Conventionally, vapor deposition, polymer binding, slip casting and the like are generally known as methods for forming a photoconductor. However, the vapor deposition method may decompose depending on the type of the photosensitive material, and the polymer binding method has a problem that it is very difficult to obtain a uniform film. Further, the slip casting method has a problem that impurities such as a solvent enter and as a result, distortion occurs when the solvent is dried. Also, since a large amount of organic solvent is used, it is a serious environmental problem.

In recent years, at the time of producing a photoreceptor, a charge generating material or a charge transporting material, which is a photoreceptor material, is dispersed or solubilized in an aqueous solvent with a surfactant,
It has been reported that electrolysis is performed in the resulting dispersion or solution to form a charge generation layer or charge transport layer made of the above-mentioned materials.

[0004]

However, the dispersion and solution used in the above method lack pH stability and are not suitable for continuous use or long-term use. There has been a problem that the pH locally changes and interferes with the formation of a thin film of the photosensitive material.

The present invention has been made to solve the above-mentioned problems, and is a dispersion liquid having excellent pH stability and capable of suppressing a local pH change near the electrode even during electrolytic treatment, It is intended to provide a solution.

[0006]

In order to achieve this object, in the method for producing a photoreceptor of the present invention, the photoreceptor material is dispersed or solubilized by a surfactant in an aqueous medium containing a pH buffer. Dispersion and solubilization step, and a dispersion material or solution obtained in the above step as an electrolytic solution, electrolysis using a conductive substrate as an electrode to form the photosensitive material thin film on the conductive substrate. A thin film forming step.

[0007]

According to the method for producing a photoreceptor of the present invention having the above-mentioned constitution, the pH stability of the dispersion or solution is improved by the action of the pH buffering agent, which enables continuous use and long-term use. A uniform change in pH near the electrode due to electrolysis is suppressed, and a uniform thin film of a photosensitive material is formed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First, the solubilization and dispersion steps will be described. Nonionic surfactant polyoxyethylene dodecyl ether (Brij35) as a surfactant and lithium bromide (LiBr) as an electrolyte in ion-exchanged water at respective concentrations of 2.0 mM (millimolar) and 0. 0.1 M (mol), and then pH buffer boric acid (H ₃ BO ₃ ) was added to 0.1 M, and the pH was adjusted to 9 with sodium hydroxide (NaOH). ..

Next, β-type copper phthalocyanine, which is a photosensitive material, was added to the above solution so as to have a concentration of 7 mM, and the mixture was stirred with a magnetic stirrer for several hours, and then 30 minutes.
Ultrasonic irradiation was performed for a minute to prepare a photosensitive material dispersion liquid. Further, the above dispersion liquid was allowed to stand at room temperature for 24 hours, and the supernatant was separated to obtain a test liquid 1. As a result of measuring the dispersion concentration of β-type copper phthalocyanine in this test solution using the absorbance, it was 5 m.
It was M, and pH was 9, and no pH change was observed.

Next, the photoconductor thin film forming step will be described. The three-electrode cell shown in FIG. 1 was used in the photoconductor thin film forming step. Aluminum substrate 2 as sample electrode (WE), platinum plate 3 as counter electrode (CE), Ag / as reference electrode (RE)
An AgCl (silver / silver chloride) electrode 4 was used. In producing the photoconductor thin film, the aluminum substrate 2 was subjected to ultrasonic degreasing in acetone for 5 minutes. Test solution 1 is put into 60 by constant temperature water tank 5.
C., the aluminum substrate 2 is put therein, and a galvanostat (constant current power supply) 6 is used for 1 minute, -1.
A cathode thin film made of β-type copper phthalocyanine and having a thickness of about 0.2 μm (micrometer) was formed on the aluminum substrate 2 by carrying out cathode energization at 0 mA / cm ² (millimeter-angle per square centimeter). The pH of the test liquid 1 after forming the photoconductor thin film was 9, and no change in pH was observed.
Further, after 24 hours from the experiment, the photoreceptor thin film forming experiment was conducted again, and similar results were obtained.

Next, for comparison, the same experiment as in the above-mentioned example was carried out without adding boric acid as a pH buffer in the solubilization and dispersion steps and without adjusting the pH with sodium hydroxide.

As a result, the pH is the same as before the dispersion of the photosensitive material.
= 5.2, pH = 4.6 after dispersion, and pH = 6.2 after forming the photoconductor thin film, and the thickness of the photoconductor thin film formed of β-type copper phthalocyanine is about 0.15 μm. , The film was non-uniform. Furthermore, 24 hours after the experiment,
In the measurement before conducting the experiment again, pH was 4.8, and the thickness of the re-formed β-type copper phthalocyanine photoreceptor thin film was about 0.12 μm, and the film was also non-uniform.

As is clear from the above, the test liquid 1 containing the pH buffer has a p
It is possible to obtain a uniform photoconductor thin film with little change in H and good reproducibility. This is because the pH is kept constant, and the hydrogen generation reaction due to the decomposition of water that occurs at the same time as the photoconductor thin film formation reaction during electrolysis is stabilized, and the local increase in pH near the electrode caused by hydrogen generation is suppressed It is considered that the corrosion of the aluminum substrate 2 is suppressed.

[0015]

As is apparent from the above description, the method for producing a photoreceptor of the present invention is characterized by the action of the pH buffer agent.
Since the dispersion or the pH of the solution is kept constant, the decomposition reaction of water that occurs at the same time as the reaction of forming a photoreceptor thin film during electrolysis is stable, and continuous use and long-term use are possible. Also,
A local change in pH near the electrode caused by a water decomposition reaction is suppressed, and corrosion of the substrate is suppressed, so that the photosensitive material thin film becomes uniform.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a three-electrode cell used for manufacturing a photosensitive material thin film in Examples.

[Explanation of symbols]

 1 Test Solution 2 Aluminum Substrate 3 Platinum Plate 4 Ag / AgCl Electrode 5 Constant Temperature Water Bath 6 Galvanostat

Claims (1)

[Claims] 1. A dispersion solubilization step of dispersing or solubilizing a photoreceptor material in an aqueous medium containing a pH (pH: hydrogen ion concentration) buffer during production of an electrophotographic photoreceptor by a surfactant. And a dispersion liquid obtained in the above step, or a solution as an electrolytic solution, electrolysis is performed using a conductive substrate as an electrode, the photosensitive material thin film, a photosensitive material thin film forming step of forming on the conductive substrate, A method for producing a photoconductor, comprising: