JPS6011847A - Manufacture of electrophotographic sensitive material - Google Patents

Abstract

PURPOSE:To easily form a thin uniform layer on a conductive substrate having not only a flat plane but curved face by forming an electrostatic charge generating layer by the electrodeposition coating in a composite type electrophotographic sensitive material. CONSTITUTION:A composite type electrophotographic sensitive material is fabricated by a layer contg. a charge generating layer and a charge transfer layer on a conductive substrate, and this charge generating layer is formed by the electrodeposition coating to facilitate formation of a thin layer (about 1mum) not only on a plane plate but also on a curved conductive substrate like a drum face. Especially when the charge generating substance is a phthalocyanine compd., it has a fine particle diameter, and a uniform thin film is easily formed. The phthalocyanine compd. differs in electrophotographic characteristics in accordance with its crystal forms, and this process has an advantage that even tau- type and eta-type metal-free phthalocyanine having peculiar crystal forms can be formed into a thin film without impairing the crystal form.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a photoreceptor that is effective for creating images by electrophotography, and particularly relates to a photoreceptor of a composite type composed of a layer of a charge-generating material and a charge-transporting material. The present invention relates to a method of manufacturing a layer of a charge generating material in a photoreceptor.

[Background of the invention]

Conventionally, methods for manufacturing a layer of a charge generating material in a composite electrophotographic photoreceptor include methods such as those disclosed in Japanese Patent Laid-Open No. 53-111735, such as a dipping method, a spray method, a bar coater method, and an application method. Ta method or Japanese Patent Application Publication No. 52-
Examples include a meniscus coating device disclosed in Japanese Patent Application Laid-open No. 65643, a doctor blade method disclosed in Japanese Patent Application Laid-Open No. 10738-1980, and a casting method presented in Japanese Patent Application Laid-Open No. 128372-1984.

In general, high sensitivity can be obtained when the thickness of the charge-generating substance layer is approximately 1/jm. Therefore, in the coating method described above, it is difficult to form a charge-generating substance layer with a uniform thickness of approximately 1 μm. ,difficult. In particular, when the conductive support is not a flat plate like a sheet but has a drum-like curved surface,
With the manufacturing method described above, it is very difficult to prevent non-uniform film thickness. On the other hand, when an inorganic compound is used as the main electrophotographic photoreceptor, for example, Se, Si, (::d and These compounds are manufactured by vacuum evaporation, sputtering, ion blasting, etc. as disclosed in Japanese Patent Publication No. 57-27839.These methods are possible because the materials are inorganic compounds. If the charge transport substance is an organic compound, the formed layer may be brittle and easily peel off because the binder resin is not used, or the bond may be broken and the substances before and after the layer formation may be different, or the phthalocyanino compound may As in the case of , the crystal form changes, resulting in disadvantages such as deterioration of the characteristics of the electrophotographic photoreceptor.

[“Objective” of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to overcome the drawbacks of conventional methods for manufacturing a charge generating material layer and to provide a manufacturing method that can easily form a uniform charge generating material layer.

[Summary of the invention]

When painting an object to be coated, electrodeposition coating is a simple method when the object has a complicated shape. The present inventors have focused on this electrodeposition coating, and have discovered that under optimal conditions, a more uniform layer of charge-generating material can be formed than in conventional manufacturing methods, and have thus arrived at the present invention.

The present invention is characterized in that, in a composite type electrophotographic photoreceptor comprising a layer of a charge-generating substance and a layer of a charge-transporting substance, electrodeposition coating is used as a method for manufacturing the layer of the charge-generating substance. In particular, when the charge-generating substance is a phthalocyanino compound, it itself has a fine particle size and can easily form a uniform thin layer. In addition, since phthalocyanino compounds have different electrophotographic properties depending on their crystal form, Japanese Patent Application No. 57-669
There is an advantage that a thin layer can be formed without impairing the crystal type even for those having a unique crystal type such as the τ type and η type metal phthalocyanino shown in No. 63.

The mixing ratio of the charge-generating substance and the electrodeposition resin is preferably in the range of 0.5 to 4 parts by weight, and particularly preferably in the range of 1 to 2 parts by weight of the electrodeposition resin per 1 part by weight of the charge-generating substance. If the blending ratio of the electrodeposition resin is a little low, the smoothness of the layer of the charge-generating substance obtained is poor, and it is difficult to obtain a uniform thin layer. Also,
On the contrary, when the proportion of the electrodeposition resin increases, a uniform film with good smoothness can be obtained, but the properties as an electrophotographic photoreceptor, particularly the sensitivity, tend to deteriorate.

In addition, when forming a layer of a charge-generating substance by electrodeposition, the formation of dust may be affected by the area ratio with the counter electrode, the distance between the electrodes, the applied voltage, the material of the support of the electrophotographic photoreceptor, etc. There are various different conditions, and it is necessary to perform them under appropriately optimal conditions. The support must be conductive, and is usually made of aluminum, brass, gold, copper, etc., and may be a sheet, thin plate, or cylindrical material with appropriate thickness, hardness, or flexibility. Also good. It may also be a plastic sheet or glass coated with gold scraps, preferably having a conductive surface and being strong enough to handle.

[Embodiments of the invention]

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

Example 1 As a charge generating substance, 50 parts by weight of ε-type copper phthalocyanide/pigment (manufactured by Toyo Ink Co., Ltd., Lionol Blue BS), electrodeposition resin (manufactured by Nippon Paint Co., Ltd., PLlooo, solid content 72
(% by weight) 125 parts by weight, 10 parts by weight of methoxymethylmelamine as a curing agent, 3.5 parts by weight of dimethylethanolamine as an additive, and 750 parts by weight of pure water were placed in a glass container, and propeller stirring and ultrasonic vibration were applied simultaneously. This was carried out for 2 hours to obtain an electrodeposited layer of charge generating material.

Next, a 100100mm x 100.1nnn aluminum foil was used as the conductive support of the electrophotographic photoreceptor, a 150+w x 150mn x 0.1mm stainless steel was used as the counter electrode, and the distance between the conductive support and the counter electrode was 10crn.
Electrodeposition coating was performed at a liquid temperature of 25C. In the electrodeposition, the conductive support was placed on the e side, the counter electrode was placed on the e side, and the applied voltage was varied as shown in Table 1. After the electrodeposition was completed, the layer formed by electrodeposition was thoroughly washed with water, and then left in an atmosphere of 150C for 30 minutes to harden, and the thickness and appearance of the charge-generating substance layer were examined. . Thereafter, 2 parts by weight of a charge transport substance having the following structural formula and 2 parts by weight of polyester resin (manufactured by Toyobo Co., Ltd., Vylon 200) are dissolved in 30 parts by weight of tetrahydrofuran, and this coating liquid is used to remove the above-mentioned transport-generating substance. A charge transport material layer was applied onto the layer using an automatic applicator (manufactured by Toyo Seiki Co., Ltd.), and after drying, the electrophotographic properties were measured (the thickness of the charge transport material layer was 10 μm). The electrophotographic properties were measured using an electrostatic recording paper tester (manufactured by Kawaguchi Electric, 5P-
428). In this case, conduct a corona discharge of -5KV for 10 seconds to charge the surface (the surface potential VO (V) immediately after charging for 10 seconds is the initial potential), and leave it in a dark place for 30 seconds (at this time, the potential is set to VO (V)). V),
(Vs./■)X100 (a) is the dark decay), expose the surface with a tungsten lung so that the illumination intensity is 2Lx, record the decay of the surface potential at this time and time, v3
Sensitivity L (halved exposure amount) is the product of the time t (seconds) required for tt to become 1/2 and the illuminance, and the results are shown in Table 1.

Table 1 - As described above, the thickness of the charge-generating material layer depends on the applied voltage during electrodeposition coating, and as the applied voltage increases by 75 degrees, the appearance deteriorates due to the occurrence of pinholes, etc.

Furthermore, as the thickness of the charge-generating material layer increases, the electrophotographic properties tend to deteriorate, and it is believed that poor appearance of the layer also has an adverse effect.

Example 2 τ-type metal-free phthalocyanine (manufactured by Toyo Ink Manufacturing) was used as the charge-generating substance, and the material for electrodeposition, curing agent, and additives were the same as those in Example 1, and the τ-type metal-free phthalocyanine was used. The mixing ratio of metal 7 talo/ani//electrodeposition resin is as shown in Table 2, and pure water is added so that the solid content concentration of τya-free metal phthalocanine and electrodeposition resin is 18% by weight. In the same manner as in Example 1, an electrodeposition coating solution containing a charge generating substance was obtained.

Next, the voltage applied during electrodeposition was 20 V for 60 seconds, and the aluminum foil was subjected to electrodeposition in the same manner as in Example 1, washed with water, and dried to obtain a charge-generating substance layer.

Thereafter, 2 parts by weight of a charge transporting substance having the following structural formula, polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., Nipilon 8)
3000) 2 parts by weight, dichloromethane as solvent 7
Using 15 parts by weight of 1.2-dichloroethane = 7/a (weighted), a layer of charge transport material (thickness: 13 μm) was formed on the layer of charge generation material in the same manner as in Example 1, and a composite material was formed. A type electrophotographic photoreceptor was obtained. Table 2 shows the results of measuring these electrophotographic properties.

In this way, when the mixing ratio of the electrodepositing resin increases, the appearance of the resulting layer is good, but the film thickness tends to decrease, and the amount of charge generating substances contained in the layer tends to decrease. Resin content tends to cause carrier trapping, resulting in poor sensitivity (E6G).

Example 3 Using a solution having the same composition as the electrodeposition coating solution A3 of Example 2, an aluminum drum with an outer diameter of 120+a+ and a length of 300 mm was used as a conductive support to form a layer of a charge inventive substance by fixing coating. It's an attempt. As the counter electrode (side e), stainless steel foil processed to have an inner diameter of 320 mm and a length of 400 mm was used, and an aluminum drum was placed in the center of the foil. Table 3 shows the electrocoating liquid temperature of 25c.

Table 3 As shown, as the applied voltage increases, the film thickness increases and pinholes also occur. Generally, the thickness of the charge transport material layer in a composite electrophotographic photoreceptor is 1 μm.
It is said that the optimal value is around 1 μm, and by appropriately setting the applied voltage conditions, a thin layer with a thickness of around 1 μm can be uniformly formed on a conductive support with a drum-like curved surface. Ta.

〔Effect of the invention〕

As detailed above, according to the present invention, a thin layer (approximately 1 μm) can be easily formed not only on a flat plate but also on a conductive support having a curved surface such as a drum. This has a great effect on improving the characteristics and productivity of photographic photoreceptors.

Agent: Patent Attorney Akio Takahashi Procedural Amendment (colors included) 4.5119 Indication of the case of Mr. Kazuo Wakasugi, Commissioner of the Patent Office, Patent Application No. 118221 filed in 1988, Title of invention: Case of a person amending the manufacturing method of electrophotographic photoreceptor. Relationship between Patent applicant name (5101 Hitachi Co., Ltd. 'M') Column of "Detailed description of the invention" of the specification subject to the new type of personal amendment.

Contents of correction attached sheet).

1. Specification, page 4, line 4 [Also,” to page 9, line 9 r There are advantages. ' Delete up to '.

2. Delete "τ type" from lines 17 and 20 on page 8 of the specification letter, and "(manufactured by Toyo Ink Manufacturing)" from line 18 of the same page.

3. Page 9, line 1 of the specification: ``Delete the τ type G.''

4. Table 2 on page 11 of the specification is corrected as follows.

Claims (1)

[Claims] 1. A composite electrophotographic photoreceptor in which a layer containing a charge-generating substance and a charge-transporting substance is provided on a conductive support,
A method for producing an electrophotographic photoreceptor, comprising forming a layer of a charge-generating substance by electrodeposition coating. 2. The composite electrophotographic photoreceptor according to item 1, wherein the charge generating substance is a 7-thalocyanine compound.