JPH04335355A - Manufacture of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To manufacture the electrophotographic sensitive body having a photosensitive layer formed by coating a conductive substrate dried by a specified water removal process in order not to cause pinhole defects, uneven coasting, coagulation, and the like and to form a good image. CONSTITUTION:The conductive substrate made of aluminum or its alloy is rinsed with an aqueous solution, immersed into warm water and then pulled up out of it, and separated from water by drying under conditions satisfying the following expression: 30<=[TL-H. omega/rho]>=60 (where TL is the temperature of the aqueous solution [ deg.C], H is the latent heat of evaporation of the aqueous solution [cal/g], omega is the evaporation amount of the aqueous solution per unit area of the conductive substrate, and rho is the specific heat of the conductive substrate per unit area [cal/cm<2>. deg.C].)

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention relates to a method of manufacturing an electrophotographic photoreceptor for use in electrophotographic devices such as copying machines and printers, and in particular, the invention relates to a method of manufacturing an electrophotographic photoreceptor for use in electrophotographic devices such as copying machines and printers, and in particular, the invention relates to a method for manufacturing an electrophotographic photoreceptor for use in electrophotographic devices such as copying machines and printers, and in particular, a method for manufacturing an electrophotographic photoreceptor made of aluminum or an aluminum alloy in an aqueous environment. After washing, the conductive substrate is immersed in an aqueous solution, pulled up from the aqueous solution, drained and dried, and then at least a binder resin and a photosensitive material are soaked in a solvent on the conductive substrate. The present invention relates to a method for producing an electrophotographic photoreceptor, in which a photosensitive layer is formed by applying a coating liquid for a photosensitive layer dissolved or dispersed in an electrophotographic photoreceptor.

0002

[Prior Art] Conventionally, in manufacturing electrophotographic photoreceptors used in electrophotographic devices such as copying machines and printers, a photosensitive layer is generally formed on a conductive substrate made of aluminum or the like. was.

[0003] Since the conductive substrate used to manufacture electrophotographic photoreceptors is generally manufactured through a mechanical process, dust, dirt, metal particles, rust, etc. If foreign matter such as oil is attached and a photosensitive layer is formed without sufficiently removing it, defects will occur in the formed photosensitive layer, making it difficult to form images using an electrophotographic photoreceptor manufactured in this way. If this is done, there are problems such as image defects occurring in the formed image and poor cleaning of the electrophotographic photoreceptor.

For this reason, conventionally, when forming a photosensitive layer on a conductive substrate, the conductive substrate is cleaned to remove dust, dirt, metal particles, etc. that have adhered to the conductive substrate.
Foreign substances such as rust and oil were removed. Here, in cleaning the conductive substrate as described above, in the past, a solvent such as Freon or 1,1,1-trichloroethane was generally used as the cleaning liquid.

However, when these solvents are released into the atmosphere, they are considered to be harmful to the earth's environment, such as by destroying the ozone layer in the stratosphere, and are now being regulated internationally. A method of cleaning the above-mentioned conductive substrate without using a wafer has been studied.

[0006] In recent years, cleaning methods using alternative CFCs, chlorinated solvents, organic solvents, water-based detergents, etc. have been developed as methods for cleaning conductive substrates without using the above-mentioned solvents. It's arrived.

[0007] However, when alternative fluorocarbons or chlorinated solvents are used, there is the same problem of environmental damage as when using solvents such as fluorocarbons, and there is a high possibility that their use will be regulated in the future. However, it cannot be used for cleaning conductive substrates for a long period of time, and when organic solvents are used, there are problems such as the cleaning work being dangerous because organic solvents are generally flammable.

[0008] For this reason, in recent years, a method of cleaning conductive substrates in an aqueous environment using an aqueous detergent has attracted attention.
Various types of water-based detergents and cleaning methods have been developed.

[0009] When the conductive substrate is washed in an aqueous environment using an aqueous detergent as described above, the selection of the detergent to be used, the draining and drying of the conductive substrate after washing, and the Wastewater treatment is a problem, and in particular, draining and drying the conductive substrate after cleaning has a large effect on the conductive substrate, and various studies have been conducted on methods for this purpose.

[0010] As a method for draining and drying the conductive substrate in this manner, the solution adhering to the surface of the cleaned conductive substrate is removed using a solvent such as a CFC substitute, isopropyl alcohol, or 5-fluorinated propanol. There have been methods such as replacing the conductive substrate with water and drying it, and immersing the cleaned conductive substrate in a high-temperature aqueous solution and drying it while pulling it up.

[0011] Here, if the solution adhering to the surface of the conductive substrate that has been cleaned in an aqueous system is replaced with a solvent such as a CFC substitute, the conductive substrate can be replaced with a CFC substitute or other solvent as described above. The same problem occurs when cleaning with water, so in recent years there has been a trend toward a method in which the conductive substrate is immersed in a high-temperature aqueous solution and then drained and dried while being pulled up from the aqueous solution. It is in.

However, when the conductive substrate is immersed in a high-temperature aqueous solution and then drained and dried while being pulled up from the aqueous solution, the conductive substrate is When a photosensitive layer is formed by coating a photosensitive layer coating liquid on which a binder resin and a photosensitive material are dissolved or dispersed in a solvent, many pinhole-like formations occur in the photosensitive layer formed on the conductive substrate. There have been problems in that noise is generated and the conductive substrate is dried unevenly, resulting in uneven coating and aggregation in the formed photosensitive layer. When an electrophotographic photoreceptor manufactured in this manner is used to form an image, a problem arises in that black and white spot noise and the like occur in the formed image, resulting in a decrease in image quality.

[0013]

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned problems when manufacturing electrophotographic photoreceptors for use in electrophotographic devices such as copying machines and printers. .

That is, in the present invention, after a conductive substrate made of aluminum or an aluminum alloy is washed in an aqueous system, the conductive substrate is immersed in a high temperature aqueous solution, and the conductive substrate is extracted from the aqueous solution. After the substrate is pulled up and dried, a photosensitive layer coating liquid in which at least a binder resin and a photosensitive material are dissolved or dispersed in a solvent is applied onto the conductive substrate to form a photosensitive layer. Suppressing the generation of pinhole-like noise in the photosensitive layer formed on the conductive substrate, and the occurrence of uneven coating and aggregation in the photosensitive layer formed due to uneven drying on the conductive substrate, When an image is formed using this electrophotographic photoreceptor, the problem is to ensure that a good image can be stably obtained without causing black and white spot noise etc. in the formed image. It is something to do.

[0015]

[Means for Solving the Problems] In order to solve the above-mentioned problems, in the present invention, after cleaning a conductive substrate made of aluminum or an aluminum alloy in an aqueous system, the conductive substrate is heated to a high temperature. immersed in an aqueous solution,
After the conductive substrate is pulled up from this aqueous solution, drained and dried, a photosensitive layer coating liquid in which at least a binder resin and a photosensitive material are dissolved or dispersed in a solvent is applied onto the conductive substrate, and the above-mentioned When producing an electrophotographic photoreceptor by forming a photosensitive layer on a conductive substrate, the above-mentioned draining and drying was performed so as to satisfy the conditions shown in the following formula [1]. 30≦[TL −H・Δω/ρ]≦60
[1] (In the above formula [1], TL is the temperature of the aqueous solution [°C], H is the latent heat of vaporization of the aqueous solution [cal/g], and Δω is the per unit surface area of the conductive substrate. Evaporation amount of the above aqueous solution [g/cm2
], ρ is the specific heat per unit surface area of the conductive substrate [ca
l/cm2・℃]. )

[0016] Here, as a method for cleaning the conductive substrate in an aqueous system, conventionally known methods can be used, such as water cleaning using pure water, ionic or nonionic Cleaning with a solution using a water-soluble surfactant, emulsion cleaning using a detergent made by emulsifying hydrocarbon solvents, higher alcohols, etc. in water, chemical cleaning such as chemical etching cleaning, and cleaning with a brush on a conductive substrate. Physical cleaning methods such as brush scraping, which uses pressure to clean, jet spray cleaning, which jets water at high pressure toward the conductive substrate, ultrasonic cleaning, and megasonic scraping, can be used in combination as appropriate. can.

A specific method for cleaning the conductive substrate in an aqueous system is, for example, by cleaning the conductive substrate with an emulsifier to remove oil stains and organic stains on the conductive substrate, and then washing the conductive substrate with an emulsifier. The conductive substrate is rinsed with water to remove the emulsifier attached to the conductive substrate, and then this conductive substrate is precisely cleaned using a surfactant solution or etching solution to remove organic substances attached to the conductive substrate. After completely removing dirt and inorganic substances, the conductive substrate is rinsed with water to remove surfactant and etching solution adhering to the conductive substrate, and if necessary, during each of the above steps. The above physical cleaning should be performed in combination.

Further, after washing the conductive substrate in an aqueous system as described above, the conductive substrate is immersed in an aqueous solution, and when the conductive substrate is pulled up from the aqueous solution and drained and dried, Usually, pure water at a high temperature of around 80°C is used as the aqueous solution, and the conductive substrate, which has been washed in the water system as described above, is immersed in the high-temperature pure water. Then, this conductive substrate is pulled out of high-temperature pure water so as to satisfy the condition shown in the above formula [1], and the conductive substrate is drained and dried.

Here, when draining and drying the conductive substrate in this way, [TL
-H・Δω/ρ] is lower than 30, uneven drying will occur on the conductive substrate, whereas when the value is higher than 60, drying will result in uneven drying of the conductive substrate. When a photosensitive layer is formed by coating the photosensitive layer coating liquid on a conductive substrate that has been drained and dried, pinhole-like noise occurs in the formed photosensitive layer.

[0020] In addition, in the aqueous solution in which the conductive substrate is immersed and drained and dried as described above, in order to adjust the evaporation rate and latent heat of evaporation, alcohol-based, ether-based, ketone-based, etc. A miscible organic solvent may be added.

[0021] Then, the photosensitive layer coating liquid is applied onto the conductive substrate thus drained and dried to form a photosensitive layer. Note that any conventional method may be used to form the photosensitive layer by coating the photosensitive layer coating liquid on the conductive substrate, and the photosensitive layer formed on the conductive substrate may be The structure may be of a laminated type in which a charge generation layer, a charge transport layer, etc. are laminated in sequence, or a single layer type in which a charge generation material, a charge transport material, etc. are dispersed together.

[0022]

[Operation] After cleaning the conductive substrate made of aluminum or aluminum alloy in an aqueous environment as described above, the conductive substrate is immersed in a high-temperature aqueous solution, and the conductive substrate is pulled out of the aqueous solution. When draining and drying is performed in a manner that satisfies the conditions shown in formula [1] above, at least the binder resin and the photosensitive material are dissolved or dispersed in a solvent on the conductive substrate. When a photosensitive layer coating liquid is applied to form a photosensitive layer, pinhole-like noise does not occur in the formed photosensitive layer, and uneven drying on the conductive substrate is also eliminated. Also, uneven coating and aggregation of the formed photosensitive layer will not occur.

[0023]

[Example] Hereinafter, a method for manufacturing an electrophotographic photoreceptor will be explained in detail, and a conductive substrate washed in an aqueous environment is immersed in a high temperature aqueous solution, and then this conductive substrate is removed from the aqueous solution. Various experiments were conducted in which the conditions for lifting and draining and drying were changed, and cases in which the conditions for draining and drying satisfied the conditions shown in equation [1] above were compared with cases in which they did not.

(Experimental Examples 1 to 25) In these experimental examples, the conductive substrate was made of JIS 6063 aluminum alloy and formed into a cylindrical shape with a diameter of 80 mm and a length of 340 mm, and its outer peripheral surface was mirror-finished. I decided to use what was given. Note that this conductive substrate had a surface area S of 1708 cm2, and a specific heat ρ per unit surface area of 0.03 cal/cm2·°C.

Then, the conductive substrate was pre-cleaned for 1 minute using a detergent (Pine Alpha ST-100S, manufactured by Arakawa Chemical Co., Ltd.) by a combination of spray cleaning and brush cleaning, and then shower cleaning and cleaning. The conductive substrate was rinsed with water for 30 seconds in combination with brush cleaning.

Next, the conductive substrate was immersed in a detergent (DK B-Clear CW-5520, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and the conductive substrate was main cleaned for 1 minute using a combination of brush cleaning and ultrasonic cleaning. .

[0027] Then, the conductive substrate thus main-cleaned was immersed in pure water and subjected to ultrasonic cleaning for 30 seconds.
Thereafter, this conductive substrate was shower-washed for 10 seconds using pure water, and this operation was repeated twice on the main-washed conductive substrate.

Next, the conductive substrate thus washed in an aqueous system was washed in Experimental Examples 1 to 5 as shown in Table 1 below.
In Experimental Examples 6 to 10, the temperature TL was 55°C in pure water.
In Experimental Examples 11 to 15, the temperature TL was 65°C, and in Experimental Examples 16 to 20, the temperature TL was 70°C.
In Experimental Examples 21 to 25, the specimens were immersed in pure water whose temperature TL was 80°C.

Thereafter, each of the conductive substrates immersed as described above was soaked in each of the above-mentioned pure waters at a rate of 5 mm/sec.
10mm/sec, 15mm/sec, 20mm/sec
c, and pulled up at a pulling speed V of 25 mm/sec, and each conductive substrate was drained and dried. Note that the latent heat of vaporization H of the pure water was 560 cal/g.

In addition, when each conductive substrate was pulled up from each of the above-mentioned pure water at each pulling speed in this way, the amount of water W [g] taken out by each conductive substrate in Experimental Examples 1 to 25 was was measured. Note that this moisture content W was determined by calculating the average value of the moisture content carried out by each of the five conductive substrates.

[0031] From the moisture content W of each experimental example measured in this way and the surface area S of the conductive substrate, experimental examples 1-
In each of the conductive substrates No. 25, the evaporation amount Δω (=W/S) of the pure water evaporated per unit surface area is determined, and the specific heat ρ per unit surface area of the conductive substrate and the temperature TL of each pure water are determined. From the value of the latent heat of vaporization H of pure water, the value [TL −H·Δω/ρ] shown in the above formula [1] was determined.

Next, the following structural formula (
For a charge generating layer prepared by adding 1 part by weight of a charge generating material consisting of a bisazo pigment shown in Chemical Formula 1) and 1 part by weight of a polyester resin (manufactured by Toyobo Co., Ltd., Vylon-200) as a binder resin to 98 parts by weight of cyclohexanone. Each coating liquid was applied by dip coating to form a charge generation layer having a thickness of 0.3 μm on each conductive substrate.

[0033]

[Chemical formula 1]

[0034] In this way, the above experimental examples 1 and 2
The state of each charge generation layer formed on each conductive substrate in No. 5 was visually inspected, and the results were compared to the temperature TL [°C] of the pure water in which the conductive substrate was immersed in Experimental Examples 1 to 25 above. , the pulling speed V [mm
/sec], the amount of water taken out by the conductive substrate W [g], and the value of [TL −H·Δω/ρ] shown in the formula [1] above, are shown in Table 1 below. Regarding the condition of the charge generation layer, a good case is indicated by ◯, a case where pinhole-like noise occurs is indicated by ×, and a case where noise due to uneven drying occurs is indicated by +.

[0035]

[Table 1]

As is clear from this result, [TL-
H・Δω/ρ] is in the range of 30 to 60, and the above [1
] In the experimental examples that meet the conditions, the charge generation layer formed on each conductive substrate does not have pinhole-like noise or uneven drying noise, and the charge generation layer is in good condition. On the other hand, in the experimental examples where the value of [TL −H・Δω/ρ] was less than 30, noise due to uneven drying was found in the charge generation layer formed on each conductive substrate. , and in experimental examples in which the value of [TL - H·Δω/ρ] exceeded 60, pinhole-like noise was found in the charge generation layer formed on each conductive substrate.

Next, 13 parts by weight of a distyryl derivative represented by the following structural formula (Chemical formula 2) as a charge transport material was added onto each conductive substrate on which a charge generation layer was formed as described above.
Polycarbonate resin (manufactured by Teijin Chemicals, K-1300)
A charge transport layer coating solution prepared by dissolving 13 parts by weight of 13 parts by weight in 87 parts by weight of dichloromethane was applied by dip coating and dried to a film thickness of 20 μm on the charge generation layer of each conductive substrate. A charge transport layer was formed.

[0038]

[Case 2]

When the electrophotographic photoreceptors of each experimental example manufactured in this way were mounted on a commercially available copying machine (manufactured by Minolta Camera Co., Ltd., EP5400) and image formation was performed, the above formula [1] was obtained. When the electrophotographic photoreceptor of the experimental example satisfying the conditions was used, there was no occurrence of black and white spot noise in the formed image, and a good image was obtained.
When using the electrophotographic photoreceptor of the experimental example in which the value of [TL -H・Δω/ρ] was less than 30, black and white spot noise did not occur in the formed image, but halftone images were formed. When doing this, drying stain noise occurred. Furthermore, when the electrophotographic photoreceptor of the experimental example in which the value of [TL -H·Δω/ρ] exceeded 60 was used, the occurrence of black and white spot noise was observed in the formed image.

[0040]

Effects of the Invention As detailed above, in the method for manufacturing an electrophotographic photoreceptor according to the present invention, after cleaning a conductive substrate made of aluminum or an aluminum alloy in an aqueous system, When the conductive substrate was immersed in an aqueous solution, pulled up from the aqueous solution, and drained and dried, the draining and drying was performed in a manner that satisfied the conditions shown in formula [1] above. When a photosensitive layer is formed by coating a photosensitive layer coating liquid on which at least a binder resin and a photosensitive material are dissolved or dispersed in a solvent, pinhole-like noise occurs in the formed photosensitive layer. In addition, uneven drying on the conductive substrate was suppressed, and uneven coating and aggregation of the formed photosensitive layer were eliminated.

As a result, when an image is formed using the electrophotographic photoreceptor manufactured by the method according to the present invention,
No black and white spot noise or the like occurs in the formed image, and good images can now be stably obtained.

Claims (1)

[Claims] Claim 1: After washing a conductive substrate made of aluminum or an aluminum alloy in an aqueous environment, the conductive substrate is immersed in a high-temperature aqueous solution, and the conductive substrate is pulled out of the aqueous solution and drained. After drying, a coating liquid for a photosensitive layer in which at least a binder resin and a photosensitive material are dissolved or dispersed in a solvent is applied onto the conductive substrate to form a photosensitive layer on the conductive substrate. When manufacturing a photographic photoreceptor, the above-mentioned draining and drying process is carried out according to [1] below.
A method for producing an electrophotographic photoreceptor, characterized in that the method is carried out so as to satisfy the conditions shown in the formula. 30≦[TL −H・Δω/ρ]≦60
[1] (In the above formula [1], TL is the temperature of the aqueous solution [°C], H is the latent heat of vaporization of the aqueous solution [cal/g], and Δω is the per unit surface area of the conductive substrate. Evaporation amount of the above aqueous solution [g/cm2
], ρ is the specific heat per unit surface area of the conductive substrate [ca
l/cm2・℃]. )