JPH0815876A - Device for producing electrophotographic photoreceptor and method therefor - Google Patents

Abstract

PURPOSE:To improve the quality, production efficiency and yield of a cylindrical electrophotographic photoreceptor in spray coating. CONSTITUTION:A cylindrical tube 3 with a cylindrical conductive substrate capable of being mounted on its periphery is horizontally supported in a spray coating booth 1 and made rotatable by a rotating driving part 4. A heating and forcedly cooling device is set in the cylindrical tube, and a spray nozzle 2 is provided and scanned in the axial direction of the cylindrical tube. When a photoreceptor is produced, the substrate is mounted on the cylindrical tube and coated in the specified manner by the spray nozzle 2, and the substrate mounted on the cylindrical tube as such is heated, dried and then forcedly cooled by the heating and forcedly cooling device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical electrophotographic photoconductor, and more particularly, to a drying / cooling device for spray coating a photosensitive layer and an electrophotographic photoconductor manufacturing device and method which defines a drying / cooling method. .

[0002]

2. Description of the Related Art Conventionally known methods for producing a cylindrical electrophotographic photosensitive member are roughly classified into two types: a dip coating method and a spray coating method. The dip coating method has an advantage that the manufacturing cost is low in the case of mass production because the apparatus structure is simple. However, under the current situation where a wide variety of devices (copiers, fax machines, printers, etc.) are being developed, the electrophotographic photosensitive drum is required to support a large amount of small quantities of different diameters, different lengths, and various prescriptions. ing. That is, what is suitable for small-quantity high-mix production is
This is a spray coating method because the equipment structure is simple and the equipment cost is low, and the product type can be easily exchanged.

[0003]

However, even in the spray coating method, when the coating film to be laminated has a formulation requiring drying, or after completion of the spray coating, the spray coating booth is taken out and dried. There have been problems such as a decrease in yield due to adhesion of dust during the process of carrying the process, and a decrease in production efficiency of the carrying work itself.

As a solution to the problem of the above-mentioned decrease in production efficiency, Japanese Patent Laid-Open No. 4-346355 proposes "a method and apparatus for manufacturing a photosensitive drum". However, with this technology, not only is the drying temperature non-uniformity affecting the quality of the electrophotographic photosensitive member (particularly in the case of a long drum) accompanied by instability of the temperature itself, but also the manufacturing equipment is forcedly cooled. Since it does not have a function, there are problems that the production efficiency in the cooling step is reduced, and that the dust is easily attached to the drum by the hot air for drying, so that the yield is reduced.

The present invention has been made in view of the above points, and an object thereof is to improve electrophotographic photoreceptor quality (electrical characteristics, uniformity), production efficiency, and yield. An object of the present invention is to provide a method and apparatus for manufacturing an electrophotographic photosensitive drum that can be used.

[0006]

According to a first aspect of the present invention, there is provided an apparatus for producing an electrophotographic photosensitive member, wherein the electrophotographic photosensitive layer is coated on a cylindrical conductive substrate, and the substrate can be mounted on the outer peripheral surface. A horizontal cylindrical tube is supported horizontally in a spray coating booth so as to be rotatable, and a heating / forced cooling device is installed in the cylindrical tube, and a spray nozzle is provided so as to be able to scan in the axial direction of the cylindrical tube. It is characterized by in this case,
It is preferable that the heating / forced cooling device is capable of automatic temperature control.

According to a second aspect of the present invention, there is provided a method for producing an electrophotographic photosensitive member, wherein a cylindrical conductive substrate is mounted on the cylindrical tube of the production apparatus according to the first aspect, and the predetermined coating is performed on the substrate by the spray nozzle. It is characterized in that the substrate is treated, heated and dried by the heating / forced cooling device while the substrate is still attached to the cylindrical tube, and then forcedly cooled.

In this manufacturing method, after applying the undercoat layer by the spray nozzle, the substrate is heated and dried by the heating / forced cooling device while being mounted on the cylindrical tube, and then forcedly cooled, and thereafter, When the charge generation layer and the charge transport layer are laminated in this order (after the lamination, the substrate is heated and dried by the heating / forced cooling device while being attached to the cylindrical tube and then forcedly cooled). In the case where the coating layer and the charge generation layer are applied in this order, the substrate is heated and dried by the heating / forced cooling device while being attached to the cylindrical tube, and then the substrate is forcibly cooled, and then the charge transport layer is laminated. (After the lamination, the substrate is heated and dried by the heating / forced cooling device while being attached to the cylindrical tube, and then forcedly cooled), and an undercoat layer, a charge generation layer, and a charge are applied by a spray nozzle. After coating in the order of the transmission layer, the substrate, and was heated and dried by the heating and forced cooling device while wearing the cylindrical tube, it is possible in the case of forced cooling.

According to a third aspect of the present invention, in the method for producing an electrophotographic photosensitive member, the predetermined coating treatment is performed in the order of undercoat layer coating, charge generation layer coating, and charge transport layer coating. After each coating process, the substrate is heated and dried by the heating / forced cooling device while being attached to the cylindrical tube, and then the substrate is forcibly cooled.

[0010]

In the apparatus for producing an electrophotographic photosensitive member according to claim 1, the base is mounted on the outer peripheral surface of the cylindrical tube, and the base is rotated integrally with the cylindrical tube by the rotary driving device, and the spray is performed. The nozzle is scanned to apply (coat). After the predetermined coating treatment, the substrate is heated and dried by a heating / forced cooling device while being attached to the cylindrical tube, and then forcedly cooled. In this way, a series of steps from coating to heating, drying, and forced cooling are performed in the spray coating booth.

In the method of manufacturing an electrophotographic photosensitive member according to the second aspect of the present invention, since a series of steps from coating to heating, drying and forced cooling are performed in a spray coating booth, dust may adhere to the surface of the substrate. In addition to this, the heating of the substrate does not adversely affect the gas generated from the coating film. Further, since the substrate is forcibly cooled, the time required for cooling is shortened.

In the method for producing an electrophotographic photosensitive member according to a third aspect of the present invention, the substrate is mounted on the cylindrical tube after the application of the undercoat layer, the application of the charge generation layer, and the application of the charge transport layer. Since it is heated and dried by the heating / forced cooling device as it is, and then forcedly cooled, in addition to the effect according to claim 2, the uniformity of each coating film is improved,
The electrical characteristics and the like are also improved.

[0013]

The present invention will be described in more detail with reference to the embodiments shown in the drawings. Example 1 FIG. 1 is a front view showing a main part of an electrophotographic photoreceptor manufacturing apparatus.
2 is a cross-sectional view of the cylindrical tube in FIG. As shown in FIG. 1, a cylindrical conductive substrate (not shown) having an inner diameter slightly larger than the outer diameter of the cylindrical tube 3 on the outer peripheral portion of the cylindrical tube 3 horizontally supported in the spray coating booth 1. Put on,
The base is rotated integrally with the cylindrical tube 3 by the rotation drive unit 4.

Further, a spray nozzle 2 is provided in the spray coating booth 1 so as to be capable of scanning parallel to the axis of the cylindrical tube 3, and the photosensitive layer is coated on the substrate by the spray nozzle 2.
Cooling water supply pipe 6, cooling water drain pipe 7, heater power supply wiring 8, temperature sensor wiring 9, through slip ring 5,
The cylindrical tube 3 is heated or cooled by a cooling water control valve (electromagnetic valve) 10 and an automatic temperature controller 11, so that the photosensitive layer coated on the substrate can be dried or cooled.

In the cylindrical tube 3 shown in FIG. 2, the cylindrical tube outer shell 12 is used.
The temperature measurement value detected by the temperature sensor 16 installed inside is input to the automatic temperature controller 11 via the slip ring 5,
The heating medium 14 is vaporized by the heater 15 to heat the outer shell 12 of the cylindrical tube. Alternatively, the cooling water control valve (electromagnetic valve) 10 is used to adjust the amount of water passing through the cooling water pipe 13 to cool the outer shell 12 of the cylindrical pipe.

As the heat medium 14, alkylbenzene, diphenyldiphenyl ether, alkylnaphthalene, hydrogenated triphenyl, dibenzyltoluene, paraffinic mineral oil or the like can be used, and the heat medium 14 corresponds to a desired heating temperature range. Then, the boiling point, the thermal conductivity, the upper limit temperature of use, and the like are taken into consideration to appropriately select.

As a heating method for the cylindrical tube 3, there are a hot air circulating heating method, a heating wire heating method, a hot water circulating heating method, a steam circulating heating method and the like, and a cooling method is a cold air circulating cooling method and a cold water circulating cooling method. A coolant (CFC, etc.) circulation cooling system or the like can be adopted.

Next, the method for producing the photosensitive member will be described in detail. When the photosensitive layer coating is a single layer, after the photosensitive layer coating is completed,
In the transfer process to the drying process, there are problems such as a decrease in yield due to dust adhesion, a decrease in production efficiency due to the transfer operation itself, and a decrease in production efficiency due to natural cooling after drying.
After the coating of the photosensitive layer, the problem can be solved by drying and forcibly cooling the substrate in the spray coating booth (performing with the substrate attached to the cylindrical tube, the same applies hereinafter).

When the photosensitive layer coating film has two layers, (1)
Gas generated during heating from the solvent or resin contained in the charge generation layer adversely affects the electrical characteristics of the charge transport layer,
(2) Non-uniformity of the charge transport layer coating film (due to the characteristics of spray coating), which occurs due to the high substrate temperature when the charge transport layer coating film is formed after drying the charge generation layer coating film, ( 3)
Regarding problems such as a decrease in production efficiency when the cooling after the charge generation layer coating film drying or the charge transport layer coating film drying is dependent on natural cooling,

After forming the charge generation layer coating film, it is dried and forcedly cooled in a spray coating booth, and after the charge transport layer coating film is formed,
This can be solved by performing drying / forced cooling in the spray coating booth, or after performing two layers of coating film formation and then performing drying / forced cooling in the spray coating booth. According to these methods, it is possible to solve the problem when the photosensitive layer coating film is a single layer.

When the coating film for the photosensitive layer is three layers, (1) the solvent or resin contained in the undercoat layer generates a gas generated upon heating with respect to the charge generation layer or the solvent or resin contained in the charge generation layer. From the gas generated during heating to the charge transport layer, adverse effects on the respective electrical characteristics,
(2) It occurs because the substrate temperature is high when the charge generation layer coating film is formed after the undercoat layer coating film is dried, or when the charge transport layer coating film is formed after the charge generation layer coating film is dried. Non-uniformity of the charge generation layer coating film or the charge transport layer coating film (depending on the characteristics of the spray coating), (3) after drying the undercoat layer coating film, after drying the charge generation layer coating film or the charge transport layer coating film. Regarding problems such as reduction in production efficiency when cooling after drying depends on natural cooling,

After formation of the undercoat layer coating film, drying / forced cooling is performed in the spray coating booth, and then a charge generation layer and a charge transport layer are sequentially formed, followed by drying / forced cooling in the spray coating booth. Alternatively, after forming the undercoat layer coating and the charge generation layer coating sequentially, dry and force cool in the spray coating booth, and after forming the charge transport layer coating, dry and force cooling in the coating booth. Or, after forming the undercoat layer coating film, dry and forcibly cool it in the spray coating booth, and after forming the charge generation layer coating film, dry and forcibly cool it in the coating booth, and further form the charge transport layer coating film. After that, it can be solved by performing drying and forced cooling in a spray coating booth, or after forming three layers of coating films sequentially and then performing drying and forced cooling in the spray coating booth. According to these methods, it is possible to solve the problem when the photosensitive layer coating film is a single layer.

Further, the problem of reduction in production efficiency due to the long drying time of each layer coating film can be solved by heating to a temperature that does not impair the uniformity of the coating layer when forming each layer coating film.

Further, the problem is that the temperature of the substrate is lowered by evaporation of the solvent contained in each layer when the coating film for each layer is formed, and the coating film for each layer becomes non-uniform. It can be solved by doing.

In the present invention, the cylindrical conductive substrate is a metal such as aluminum or nickel, or a belt or drum formed by coating or depositing a conductive substance on the surface of a film-shaped plastic. The undercoat layer is a conductive pigment mainly composed of a metal oxide such as titanium oxide, barium sulfate, zinc oxide or tin oxide dispersed in a binder, a dispersant or the like. The charge generation layer is an azoxybenzene type, a disazo type, a trisazo type, a benzimidazole type, a polycyclic quinone type, an indigoid type, a quinacridone type, a perylene type or a methine type. The charge generation layer may contain a resin as a binder or a dispersant.

The charge-transporting layer is made of poly-N-vinylcarbazole, halogen poly-N-vinylcarbazole, polyvinylpyrene, polyvinylintroquinoxane, polyvinylbenzothiophene, polyvinylanthracene, polyvinylacridine, polyvinylpyrazoline, or the like, a silicon resin, It is mixed and dispersed with a binder such as polyamide, polyurethane, polyester, epoxy resin, polyketone, polycarbonate, polystyrene, polymethylmethacrylate, and polyacrylamide. The charge transport layer may contain a plasticizer, a pinhole inhibitor, a leveling agent and the like.

Solvents used for the photosensitive layers include methanol, ethanol, propanol, isopropanol,
Alcohols such as butanol, aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, dichloromethane, dichloroethane, carbon tetrachloride, tetrahydrofuran, ethers such as ethylene glycol dimethyl ether and ethylene glycol diethyl ether, acetone,
Ketones such as methyl ethyl ketone and cyclohexanone,
From esters such as ethyl acetate, methyl acetate, etc., water, etc., one or more kinds suitable for the pigment or binder in each layer are selected and mixed and used.

Next, a test example will be described. [Test Example 1] In the apparatus shown in FIG. 1, an aluminum drum having a diameter of 120 mm and a length of 680 mm was mounted on the cylindrical tube 3, and after applying the undercoat layer by the spray nozzle 2, the drum was mounted on the cylindrical tube 3 while the drum was mounted. After heating and drying at 130 ° C. for 30 minutes through the tube 3, forced cooling was performed with cooling water. Next, in this apparatus, a charge generation layer was formed on the drum on which the undercoat layer had been applied by the above method, and then dried and cooled in the same manner as the above method. Further, in the above-mentioned apparatus, a charge transport layer was applied onto the drum on which the charge generation layer had been applied in the same manner as in the above method, followed by drying and cooling to form a photoconductor (drying and forcing in a spray coating booth). cooling).

[Test Example 2] In the apparatus shown in FIG.
An aluminum drum having a length of 20 mm and a length of 680 mm is mounted on the cylindrical tube 3, the undercoat layer is applied by the spray nozzle 2, the drum is taken out of the spray coating booth 1, and dried at 130 ° C. for 30 minutes by an external drying furnace. Natural cooling was performed outside the drying oven until the temperature reached room temperature. Next, in the above apparatus, after the charge generation layer was formed on the undercoat layer-coated drum by the above method, drying and cooling were performed in the same manner as in the above method. Further, in the above apparatus, after the charge transport layer was applied onto the drum on which the charge generating layer had been applied in the same manner as in the above method, drying and cooling were performed in the same manner as in the above method to form a photoreceptor (spray coating). Drying and cooling outside the booth).

[Test Example 3] In the apparatus of FIG.
An aluminum drum having a length of 20 mm and a length of 680 mm was mounted on the cylindrical tube 3, and an undercoat layer, a charge generation layer, and a charge transport layer were sequentially laminated by the spray nozzle 2. Cylindrical drum 3
After being heated and dried by the cylindrical tube 3 at 130 ° C. for 30 minutes, the photosensitive body was formed by performing forced cooling with cooling water (drying in the spray coating booth and forced cooling).

In all of Test Examples 1, 2, and 3, the photoconductor formulation is a formulation in which the gas generated when the solvent contained in the undercoat layer is dried adversely affects the upper charge generation layer.

In each of Test Examples 1, 2, and 3, 20 photoconductors were formed, and the production tact, appearance yield (coating film defect due to dust adhesion), and electrical characteristics (by photoconductor electrical property evaluator) of these were measured. Examined. The results are shown in [Table 1].

[0033]

[Table 1]

After the undercoat layer was applied in Test Example 1, the temperature of the substrate surface changes with time when forced cooling by a cylindrical tube is performed, and in Test Example 2, after the undercoat layer is applied, the substrate surface is cooled naturally. The change in temperature with time is shown in FIG. As is clear from this figure, in Test Example 1, the temperature of the substrate surface can be lowered to room temperature much faster than in Test Example 2.

[0035]

As is apparent from the above description, claim 1
According to the apparatus for manufacturing an electrophotographic photosensitive member described in [1] or the method for manufacturing an electrophotographic photosensitive member described in [2], a series of steps from coating to heating, drying, and forced cooling is performed in a spray coating booth. Therefore, there is no risk of dust adhering to the surface of the base, and heating of the base does not adversely affect the gas generated from the coating film, so that the quality and yield of the photoconductor are improved. Further, since the substrate is forcibly cooled, there is an effect that the time required for cooling is shortened and the production efficiency is improved. According to the method for producing an electrophotographic photosensitive member of claim 3, after the undercoat layer is applied, the charge generation layer is applied, and the charge transport layer is applied, the substrate is heated while being attached to the cylindrical tube.・ After heating and drying with a forced cooling device,
Since it is forcibly cooled, in addition to the effect according to the second aspect, there is an effect that the uniformity of each coating film is improved and the electric characteristics and the like are further improved.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the device of the present invention.

FIG. 2 is a cross-sectional view of a cylindrical tube in the apparatus shown in FIG.

FIG. 3 is a graph showing the temperature lowering characteristics of the substrate surface in Test Example 1 and Test Example 2.

[Explanation of symbols]

 1 Spray Coating Booth 2 Spray Nozzle 3 Cylindrical Pipe 4 Rotational Drive 5 Slip Ring 6 Cooling Water Supply Pipe 7 Cooling Water Drain Pipe 8 Heater Power Supply Wiring 9 Temperature Sensor Wiring 10 Cooling Water Control Valve 11 Automatic Temperature Controller 12 Cylinder Outer shell 13 Pipe for cooling water 14 Heat medium for heating 15 Heater 16 Temperature sensor

Claims (3)

[Claims] 1. An apparatus for coating an electrophotographic photosensitive layer on a cylindrical conductive substrate, wherein a cylindrical tube on the outer peripheral surface of which the substrate can be mounted is supported horizontally in a spray coating booth and is rotatable. In addition, an apparatus for manufacturing an electrophotographic photosensitive member, characterized in that a heating / forced cooling device is incorporated in the cylindrical tube, and a spray nozzle is provided so as to be capable of scanning in the axial direction of the cylindrical tube. 2. The manufacturing method according to claim 1, wherein a cylindrical conductive substrate is mounted on the cylindrical tube, a predetermined coating process is performed on the substrate by the spray nozzle, and the substrate is mounted on the cylindrical tube. A method for producing an electrophotographic photosensitive member, which comprises heating and drying by the heating / forced cooling device as it is, and then forcedly cooling. 3. The predetermined coating treatment is applied to an undercoat layer,
The charge generation layer is applied and the charge transport layer is applied in this order, and after each application treatment, the substrate is heated and dried by the heating / forced cooling device while being attached to the cylindrical tube, and then forcedly cooled. The method for manufacturing an electrophotographic photosensitive member according to claim 2, wherein