JPH02272561A - Method for drying coating film layer of electrophotographic sensitive body to finger touch - Google Patents

Abstract

PURPOSE:To improve the uniformity of a coating film and the coating efficiency by sealing the solvent vapor generated from a coating liquid film to the circumference of the coating liquid film during the prescribed time during and after the discharge of a coating compd. CONSTITUTION:A base body cylinder 1 is rotated in a hood 13 and while the coating liquid 4 is discharged in a stripe shapes from a nozzle tip 12 according to the movement of a gun 5, the coating liquid is applied linearly on the cylinder 1 from a slit-shaped aperture 16 provided in the generator direction of the hood 13. The leveling of the linear coating compd. remaining in waveforms progresses and the flat surfaces are successively formed in the previously coated part 14 on progression of the coating. The solvent vapor on the cylinder 1 is sealed into the hood 13 and the solvent vapor attains saturation in the space volume of the jig hood 13 so that the leveling of the applied coating compd. progresses in an air-liquid equil. state in the hood 13. The uniformity of the coated film and the coating efficiency are improved in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a simple and low-cost method for drying a coating layer of an electrophotographic photoreceptor to the touch, which has excellent potential uniformity and durable images.

[Prior Art] Conventionally, as a method of forming a coating film on an object to be coated using a paint, for example, the object to be coated is immersed in the paint and gradually pulled up to reduce the interfacial tension between the object and the paint. There are two known methods: a dip coating method in which a paint film is formed by using a roll, and a roll coating method in which a paint layer is once formed on a roll and then a paint film is formed by transferring the paint layer onto the object to be coated. There is.

Also, there is a spray method in which paint is ejected from a nozzle having a minute opening and atomized to form a coating film by depositing minute droplets on the object to be coated, or Japanese Patent Application Laid-Open No. 52-1
As disclosed in Japanese Patent No. 19651, a liquid injection coating machine or a curtain coating machine is placed close to the surface of the object to be coated,
A method has been proposed in which the viscosity and surface tension of the paint are used to support the paint between the object to be coated and a pour coating machine or a curtain coater, thereby forming a film while preventing paint leakage.

In these coating methods, in order to form a film in a predetermined range with a predetermined thickness distribution, the paint is applied during the coating process, or
Various measures are taken after attachment. For example, regarding the dip coating method, there is a method using a shielding plate (hood) as disclosed in Japanese Patent Laid-Open No. 59-42060, and a coating method as disclosed in Japanese Patent Laid-Open No. 59-225771. There is a method of applying air flow in the same direction as the pulling direction immediately after pulling up.

For example, regarding the spray coating method, JP-A-62-
As disclosed in Japanese Patent No. 75454, a method is used in which the coating is applied in a booth that covers the base cylinder, and after the coating, the gas is blown and exhausted to dry to the touch.

Alternatively, as disclosed in Japanese Unexamined Patent Publication No. 59-5805, a method is used in which a coating liquid is applied in a spiral manner and then the solvent used in the coating is sprayed to perform leveling.

There are the above examples, but all of them aim to perform homogeneous leveling during and after coating, and furthermore, to obtain a uniform film.

[Problems to be Solved by the Invention] However, the above conventional example has the following drawbacks. In the case of shielding hoods in dip application methods:
To control solvent vapor immediately after application, consideration must be given to the diameter and length of the shield hood relative to the diameter of the base cylinder.

In addition, if you do not use a hood and blow air to dry the paint to the touch during or immediately after pulling up the paint, be sure to take into account the wind direction, wind speed, and scenery. Extreme difficulties arise.

In addition, in the case of the spray application method, there is a proposal to apply the product inside a booth and blow and exhaust the air, but since the paint is spread widely and sprayed, there is a lot of mist of paint and air inside the booth. are mixed, so the amount of solvent evaporates a little,
Paint is deposited on the base cylinder. At this time, if the amount of solvent contained in the coated surface is sufficient for leveling, a more homogeneous coating film will be obtained; if it is insufficient, supplementary supply of solvent vapor will be required.

When blowing or exhausting air after spray coating, the condition is that the coated surface be homogeneous. However, in reality, as described above, it is difficult to secure the amount of solvent necessary for leveling because air is mixed in the coating.

Compared to the spray coating method, the spiral coating method using a liquid injection coating machine or curtain coating machine tends to cause less solvent in the paint to dissipate and to facilitate leveling.

However, in this case as well, depending on the type of solvent in the paint, it may be necessary to level the paint by spraying the solvent after coating, as disclosed in JP-A-59-5805.

The present invention can eliminate the influence of airflow during coating, leveling proceeds without adding solvent vapor after coating, and is dry to the touch with controlled exhaust air. An object of the present invention is to provide a method for drying a coating layer of an electrophotographic photoreceptor to the touch, which is excellent in surface condition, uniformity, and thickness distribution and free from coating defects.

In addition, the present invention is simple and does not require an increase in the size of the device (it has good coating efficiency and does not require an exhaust device for removing scattered paint and collecting dust). The purpose is to provide a drying method.

[Means for Solving the Problems] That is, the present invention provides an electrophotographic photoreceptor that can be applied to an electrophotographic photoreceptor from a paint discharging gun having minute openings on the surface of the support for the electrophotographic photoreceptor or on a coating layer on the surface thereof. In a method for manufacturing an electrophotographic photoreceptor, which includes discharging a forming paint without substantially atomizing it to form a paint liquid film, and drying the hindlimb paint liquid film to the touch, This is a method for drying a coating layer of an electrophotographic photoreceptor to the touch, characterized in that a solvent vapor generated from the coating liquid film is enclosed around the coating liquid film for a predetermined period of time after the coating liquid film is discharged.

Furthermore, the present invention provides the above-mentioned touch drying method, further characterized in that the enclosed atmosphere is evacuated at a constant air volume after a predetermined period of time.

Further, the present invention provides a valve at a portion of the exhaust pipe for exhausting,
The above-mentioned touch drying method is further characterized in that the drying method is carried out in such a manner that the opening is opened during exhaustion.

One possible method for controlling the solvent atmosphere is to obtain the solvent atmosphere necessary for leveling by, for example, spraying an appropriate amount of the solvent in the paint in a curtain coater after applying the paint (Japanese Patent Application Laid-Open No. 1986-1
50053).

However, following the application part of the curtain coating machine,
When spraying a solvent, the solvent droplets will adhere to the previously formed film, causing dotted craters.
They tend to form marks. In addition, when trying to reduce such crater-like marks, it is necessary to achieve extremely fine droplets or to supply so much solvent that the crater-like marks overlap each other and there are no traces. It becomes necessary.

Alternatively, for example, there is a method in which a plate is provided for the spray airflow generated during spray scanning, and the spray airflow is confined therein to maintain the saturated state of the paint solvent and suppress the drying of the paint droplets. It has been reported (Japanese Unexamined Patent Publication No. 62-75456).

However, in the case of air spraying, a large amount of atomized solvent is already present in the spray air stream, and even with inserts, it is difficult to achieve the saturation conditions necessary to obtain good leveling of the coating film. Have difficulty. Furthermore, since air is blown at the pressure necessary for atomization, the coated surface, which still has fluidity as described above, will be greatly disturbed.

When spraying is airless, the paint is pressurized and discharged to atomize without using atomizing air, so it adheres to the base cylinder in a state containing a large amount of solvent and forms a coating film. Therefore, it still retains sufficient disability. For this reason,
The paint particles that have been atomized under high pressure and obtained a high velocity collide and adhere to the previously formed coating film while overlapping, so that the coated surface is extremely disturbed.

Therefore, in the present invention, in order to improve the film-forming properties of the paint film, in a method of discharging paint from a minute opening without substantially atomizing it to form a paint film on the object to be coated, as well as,
A means (hereinafter referred to as a hood) for sealing the solvent vapor generated from the paint liquid film around the paint liquid film after completion of coating was provided to ensure sufficient leveling.

The base cylinder remains in the hood not only during coating but also after coating, and during that time the solvent vapor generated from the coated surface quickly fills the space between the base cylinder and the hood, thereby reducing the required amount of the coated surface. Fluidity is ensured and the uniformity of the coating film is improved.

Of course, in the case of air spray and airless spray, the leveling performance is improved to some extent by the hood related to the present invention, but since the solvent evaporates during application, the application method according to the present invention has no effect. do not have.

That is, the method of discharging the paint from a minute opening without substantially atomizing it and applying it onto the object to be coated makes it possible to effectively enclose the solvent vapor in the hood.

In addition, since the paint is a system in which the paint flies without being atomized, the ratio of the space occupied by the paint is extremely high. Therefore, it is thought that the local space covering the base cylinder is filled with solvent vapor of almost the same composition as the mixed solvent vapor generated from the solvent composition in the initial paint, so that the paint is There is little risk of degeneration.

Next, the exhaust of solvent vapor and the like will be explained.

In the case of dip coating methods, the equipment is designed to vent trapped solvent vapors within the enclosure. There are proposals to install a hood over the coating pot to control the solvent vapor and improve leveling, but they do not take into consideration the point of actively exhausting the solvent vapor inside the hood.This is a dip coating method. In this case, a shear force acts between the coating liquid surface and the coating film, forming a constant liquid film as the cylinder is pulled up, and even in the process of being pulled up, the liquid that has adhered more than necessary drips downward. Furthermore, as the liquid film is controlled and the solvent vapor rises in the distance between the hood and the cylinder, drying to the touch progresses gently, so it was thought that it would be better not to supply or exhaust unnecessary air. It seems to be for a reason.

The situation is different with spray application methods. A large amount of air containing solvent vapor is supplied by the sprayer, and the mist-like paint does not adhere to the cylinder but floats inside the booth and later adheres unevenly in the dry state, so it is not normal. Therefore, as mentioned above (,
In order to remove unnecessary paint droplets, solvent vapor and air, it is necessary to install an exhaust duct opposite the spray nozzle.

In order to level the coated surface, it is necessary to contain the solvent vapor necessary to obtain fluidity of the coating film, but in the case of spray coating, it is necessary to contain a sufficient amount of solvent vapor for a certain period of time using a large volume of air. This is extremely difficult because it atomizes. Therefore, as mentioned above, a means for supplying solvent vapor by spraying is required. Even if the solvent is supplied in this way, it is difficult in practice because it is necessary to simultaneously satisfy the contradictory requirements of eliminating a large volume of air, etc. and containing the solvent vapor. Therefore, it is conceivable to separate the above two contents and supply and contain the solvent vapor after spray coating.

The key point of the present invention is to control and exhaust the solvent vapor after coating, and to emit the solvent vapor from the leveled coating surface while maintaining its uniformity, and to obtain a dry-to-the-touch condition. The structure of the forced exhaust pipe had to be carefully devised.

A simple and efficient device that is dry to the touch has a coating method in which paint is ejected from minute openings without substantially atomizing to form a coating film on the object to be coated, for example. This is achieved when using a beam coating method. Therefore, it can be seen that the present invention is effective in the same device during and after coating, and during forced exhaust when dry to the touch.

In addition, by providing a valve in the exhaust pipe, the slight effect on the coated surface that occurs when there is some ventilation between the valve opening and the hood opening during coating and during leveling after coating can be suppressed. better surface condition.

One option is to take it out of the hood and forcefully exhaust it while it is in contact with the outside air, but this would not be very efficient in drying as it would also exhaust the surrounding air in addition to the solvent vapor. Also, since the air around the coated surface is forced to move, sufficient consideration must be given to the exhaust air speed to avoid uneven drying.

A specific example of the apparatus used in the touch drying method of the coating layer of the electrophotographic photoreceptor of the present invention is shown in FIG.

In FIG. 1(a), 1 is a base cylinder, which is fixed to a rotating shaft 2 which also serves to hold the cylinder. Further, the rotating shaft 2 is rotated by a rotating motor 3 at a predetermined rotational speed. To form a coating film, a beam-shaped coating liquid 4 is discharged from the tip of a gun 5 placed on a pedestal 6 of a lateral feed mechanism, and a spool-shaped coating liquid 4 is discharged onto the base cylinder (see Fig. 1 (b)).
This is done by attaching it to the surface and leveling it.

In the tank 9, the compressed air introduced through the air pipe 10 pressurizes the paint inside the tank to the pressure determined by the gauge 11, and the paint in the tank is then passed through the filter 8 and the outlet pipe 7 to the nozzle tip 12 (the first one) at the tip of the gun. (see figure (c)).

The gun's lateral feed mechanism switch and the gun needle's air switch are set, and the beam 4 is discharged from a predetermined position of the base cylinder 1. At the same time, turn on the motor switch and rotate the rotating shaft holding the base cylinder, and the beam 4
is a pattern like a thread cut on the base cylinder 1 (
(see Figure 1 (b)), and due to the collision energy of the paint and the interfacial tension between the paint and the object being coated, it spreads widely, and adjacent beams come into contact with each other, causing the coating surface of the object to be coated. Cover without any gaps (see Figure 1 (d)). After an appropriate amount of time has passed due to the diffusivity of the paint and the interfacial tension between the paint and the object being coated, the initial unevenness of the paint film that occurred depending on the pitch is smoothed out (see Figure 1 (d)), and the surface becomes smooth. You can get a good side. In the present invention, a hood is also used to control the solvent vapor of the paint, resulting in a smoother surface.

The pitch of the line of spools formed by the beam is determined by the rotation speed and gun feed rate.

Further, the amount of coating liquid per unit area is determined by the feed speed if the discharge amount is constant.

Discharge amount per unit area (cc/min・am2): Discharge pressure (
kgf/ca+”): Discharge diameter (c+a) Niorifice bearing length (am): Feed rate (am7 minutes) Regarding the pitch width of the beam, the following relationship is ΔV engineering υ.

p, oc t' Pw: Beam pitch width (cm) Ro Niji cylinder - rotation speed (rpm) FIG. 1(c) shows a specific example of a paint discharge port.

Although FIG. 1(c) shows a nozzle chip 12 having a standard single outlet, a nozzle chip having three outlets may be used to increase the rate of coating film formation.

FIG. 1(b) shows a schematic diagram of a jig hood 13 (for example, the diameter is 1001 mm compared to the cylinder diameter of 80 III11) for controlling the solvent vapor of the paint during coating.

The base cylinder 1 is rotated in the jig hood 13, and as the gun 5 moves, the nozzle tip 12 is opened through a slit-shaped opening 16 provided in the generatrix direction of the jig hood.
While discharging the coating liquid 4 in a streaky manner, the coating liquid 4 is applied onto the base cylinder in a spool shape 15.

As the coating progresses, the spool-shaped paint remaining in the waveform in the previously coated portion 14 progresses to leveling, forming a flat surface as shown in FIG. 1(d).

At this time, due to the presence of the jig hood 13, the solvent vapor on the base cylinder 1 is sealed in the jig hood, and the solvent vapor reaches saturation in the space volume of the jig hood 13, resulting in a state of vapor-liquid equilibrium. The leveling of the applied paint progresses.

When there is no jig hood, the amount of solvent contained on the coating surface differs between the beginning of coating and the coating line.
If there is a jig hood, even if the solvent evaporates from the coated surface at the beginning of coating, it will be encapsulated in the jig hood, so the amount of solvent contained on the coated surface at the end of coating will be almost the same as at the beginning. considered to be a thing.

In other words, as described above, the gap between the jig hood and the outer diameter of the drum is designed so that there is no difference in the amount of solvent contained on the coating surface between the end and the beginning of coating. In the case of Fig. 1 (b), the gap is set at 10 mm, but the smaller the gap, the smaller the space volume in the jig hood (because the solvent vapor reaches saturation and vapor-liquid equilibrium is not achieved). Also, depending on the solvent used, the vapor pressure and boiling point will differ, so it is necessary to change the gap.

After a leveling time that is individually set depending on the solvent used and the coating thickness, the solvent vapor filling the hood 13 is
0.1 via the forced exhaust pipe 17 as shown in Figure (a).
By exhausting the air at a wind speed of 0.8 m/s to 0.8 m/s, the drying time to the touch can be shortened. It has also been confirmed that the coating film is formed to approximately the same extent as when it is taken out from the hood after leveling and dried to the touch naturally.

In the present invention, it is more preferable to provide a valve 18 at a portion of the exhaust pipe as shown in FIG. 2(b) for the reasons described above.

The electrophotographic photoreceptor-forming paint that can be used in the present invention includes a photosensitive layer-forming paint such as a charge-generating layer-forming paint and a charge-transporting layer-forming paint, or a subbing layer for improving adhesiveness and barrier properties. Examples include paints for formation, and paints for forming intermediate layers such as paints for forming conductive layers for preventing local batteries in metal cylinders and concealing defects.

The method of the present invention is most preferably applied to form all of the conductive layer, subbing layer, charge generating layer, and charge transport layer, but may be applied to any number of layers, such as one or two of these layers. The counterfeit may be formed by another coating method such as a dip coating method, or the layer structure of the electrophotographic photoreceptor may not include a conductive layer and/or an undercoat layer.

Furthermore, in the structure of the photosensitive layer, the charge generation layer may be formed on the charge transport layer, and the photosensitive layer may be of a single layer type instead of a laminated type.

Example 1 To prepare a conductive layer coating, 10 parts of phenolic resin,
Titanium oxide 1 surface treated with tin oxide and antimony oxide
1 part by weight, 11 parts of titanium oxide surface-treated with alumina,
4 parts of methanol, 9 parts of methyl cellosolve, and 1 mm hard glass beads for dispersion were added in the same volume as the material, and dispersed for 2 hours using a sand mill disperser. The dispersed paint was diluted with a 1:1 mixed solvent of methanol and methyl cellosolve to a solid content of 40%. At this time, the viscosity of the paint was 15 cps.

This paint was put into the conductive layer coating tank of the type of coating device shown in Fig. 1(a), and a diameter of 100 μm was placed at the tip of the beam gun.
Install a nozzle tip of 0.6kgf/c to the tank.
When an air pressure of "a+" was applied and the amount of paint discharged from the gun was measured, it was 5 g/min.

Next, adjust the distance between the gun and the object to be coated to 20 mm,
An aluminum cylinder with a diameter of 80n+m and a length of 360mm was installed on a rotating gripping shaft in a hood with a diameter of 100a+m, and the number of rotations was 1100 rpm, and the gun feed rate was 150 mm per minute.
The conductive layer was applied via a 20 mm slit.

Special terms for the coating process: The paint adheres to the cylinder in the form of a thread with a width of 2n+m, and then the overlapping lines of paint that are applied mix and leveling begins, and after 5 minutes, a smooth surface with a surface roughness of 0.4μm or less is formed. The beam became flat and the pitch unevenness of the beam disappeared. This coating film was forcibly evacuated at a wind speed of 0.4 m/s using the jig shown in FIG. 2(a) to evaporate the solvent, and then cured in a drying oven at 150° C. for 30 minutes. The thickness of the conductive layer thus obtained was 20 μm.

After cooling the aluminum cylinder coated with the conductive layer to room temperature, as an undercoat layer, 1 part of polyamide resin and 3 parts of methoxymethyl-modified 6-nylon polyamide resin were dissolved in 130 parts of methanol and 66 parts of 1-bratanol. , made a paint for the undercoat layer.

Put this paint into the undercoat layer paint tank of the same coating device as above, attach a nozzle tip with a diameter of 100 μm to the tip of the gun, apply a pressure of 0.6 kgf/cm'' to the tank, and measure the amount of paint discharged from the gun. The rate was 3 g per minute.The distance between this gun and the object to be coated was adjusted to 201101, and the cylinder on which the conductive layer was coated was rotated at a speed of 12.
Orpm, the undercoat layer was applied at a gun feed rate of 250 mm per minute. The width of the beam of the undercoat layer deposited on the conductive layer is approximately 3 mm, and the paint adheres in the form of threads, and the overlapping lines of paint that are applied subsequently mix and begin leveling, and after 5 minutes, the surface roughness is removed. The beam became smooth to 0.1 μm, and the pitch unevenness of the beam disappeared. This coating film was forcibly evacuated at a wind speed of 0.4 m/s using the jig shown in FIG. 2(a) to evaporate the solvent, and then dried in a drying oven at 90° C. for 10 minutes. The thickness of the undercoat layer obtained in this way was 0.
．． It was 5 μm.

The aluminum cylinder coated with the undercoat layer was cooled to room temperature. Next, as a charge generation layer, poly(vinyl)
10 parts of acetate-corvinyl alcohol-corvinylbenzal) were dissolved in 90 parts of cyclohexanone,
Add 25 parts of organic disazo pigment as a solid content to this solution, further add 300 parts of cyclohexanone and 250 parts of tetrahydrofuran, and add 1 m in diameter equal to the total amount.
90Or in a sand mill with m hard glass beads.
After dispersing the beads at pm for 40 hours, microhexanone was added to adjust the solid content to 0.5%.

Put this paint into the charge generation layer coating tank of the same coating device as above, attach a nozzle tip with a diameter of 75 μm to the tip of the beam gun, apply a pressure of 0.5 kgf/cab to the tank, and measure the amount of paint discharged from the gun. As a result, 1.0% per minute.
It was 1g.

Next, adjust the distance between this gun and the object to be coated to 10 mm, and while rotating the above-mentioned cylinder used for coating the conductive layer and undercoat at a rotation speed of 6 Orpm, rotate the beam gun at a speed of 100 mm per minute to the generating line of the cylinder. The charge generating layer was applied.

The width of the beam of the charge generating layer deposited on the undercoat layer is approximately 1.
At 5mm, the paint adheres in the form of a thread, and then the overlapping lines of paint are mixed and leveling begins.After 5 minutes, the coating film becomes uniform and becomes a surface with no density unevenness, and the pitch unevenness of the beam is eliminated. Na (became)

This coating film was coated at 0, 2rn/
After the solvent was evaporated by forced exhaust air at a wind speed of 1.5 sec, the solution was dried in a drying oven at 90° C. for 5 minutes. The thickness of the charge generation layer thus obtained was 0.15 μm.

The aluminum cylinder coated with the above charge generation layer was cooled to room temperature. Next, as a charge transport layer, 10 parts of polycarbonate resin and a hydrazone compound (P-(N, N-
9.5 parts of (diethylamino)benizaldehyde (N-α-naphthyl-No-phenylhydrazone) were dissolved in 100 parts of monochlorobenzene and 40 parts of dichloromethane. Put this paint into the charge transport layer coating tank of the same coating device as above, attach a nozzle tip with a diameter of 150 μm to the tip of the beam gun, and apply an air pressure of 0.6 kgf/cm to the tank to control the amount of paint discharged from the gun. The measured amount was 12.5 g/min.

Next, adjust the distance between this gun and the object to be coated to 20 mm, apply the coating to the charge generation layer, and then attach the aluminum cylinder to 12 mm.
Beam gun 200nu per minute while rotating at 0rpm
The charge transport layer was applied by moving it in the direction of the generatrix of the cylinder using ++.

The beam width of the charge transport layer deposited on the charge generation layer is approximately 2
．． At 5mm, the paint adheres in the form of threads, and then the overlapping paint lines are mixed and leveling begins.After 5 minutes, the surface becomes a smooth surface with a surface roughness of 0.2μm or less, and the pitch unevenness of the beam is eliminated. After evaporating the solvent by forcibly exhausting the film at a wind speed of 0.5 m/s using the jig shown in Figure 2 (a), dry it for 60 minutes in a drying oven at 120°C. I let it happen.

The film thickness thus obtained was 20 μm.

When the OPC photoreceptor thus completed was attached to a copying machine (Canon NP-3525) and an image was produced, the same high image quality as that produced by conventional dipping coating was obtained. In addition, this photoreceptor was subjected to a durability test,
After printing 50,000 images, the images remained clear and high-quality until the end.

Example 2 The same paints and application equipment as in Example 1 were used. However, instead of the jig shown in Figure 2(a),
The experiment was carried out using the jig shown in Figure (b), that is, by replacing the system with a valve that opens only when exhausting, in the middle of the way from the forced exhaust pipe to the exhaust duct.

I found that there was not much difference in finger touch, but I found that the leveling condition was slightly improved.

When the completed electrophotographic photoreceptor was evaluated, excellent characteristics similar to those of Example 1 were obtained.

Comparative Example 1 After applying each paint under the same coating conditions as Example 1,
Instead of exhausting at a constant wind speed as in Example 1, the air is evacuated at 0.
Each layer was formed by drying to the touch at an exhaust speed varying from 2 m/s to 2 m/s, and an electrophotographic photoreceptor was completed.

When this was evaluated using the same image forming apparatus as in Example 1,
The uneven drying of the paint appeared as image unevenness, which was thought to be caused by the abnormal wind flow caused by the change in exhaust speed.

Comparative Example 2 Each paint was applied at the same gun feed speed and base cylinder rotation speed as in Example 1. However, in this example, in order to clarify the difference between the presence and absence of a hood, the coating and drying to the touch were performed without using a hood. In addition, the area around the base cylinder was covered to avoid the influence of special winds, and care was taken to prevent uneven drying.

As for the drying time to the touch, when forced exhaust air was used in Example 1, the coated surface was not wet for 3 to 7 minutes for each layer, whereas in this comparative example, it took 1 to 1
It took 0 to 30 minutes.

Regarding drying unevenness, in the case of Example 1, an excellent image was obtained without any unevenness, whereas in this example, which was applied without a hood, the uniformity of the coating film was poor due to insufficient leveling. However, streak-like unevenness and large wavy-like unevenness due to coating were sometimes observed.

[Effects of the invention] As explained above, by adopting the method of the present invention, 1. There is no need to supplementally supply the solvent by spraying, etc.
There is no need for jigs or equipment for this purpose.

2. Also, by selectively forcibly exhausting the solvent vapor trapped in the hood, drying to the touch can be achieved quickly.

3. Therefore, even if the exhaust air speed is suppressed and the exhaust air is exhausted, the solvent can be effectively transported out of the system, while maintaining a good surface condition.
Can be quickly dry to the touch.

4. Therefore, since the amount of exhaust gas can be reduced, there is no need to circulate or take out the air in the coating chamber more than necessary.

[Brief explanation of drawings]

FIG. 1(a) is a schematic explanatory diagram showing an example of the apparatus used to implement the present invention, FIG. 1(b) is a schematic explanatory diagram showing the coating state in the hood, and FIG. 1(d) is a schematic explanatory diagram showing a change in the state of the painted surface; FIG. 2(a) is a schematic explanatory diagram showing an example of a forced exhaust device; (b) is a schematic explanatory diagram showing an example of a forced exhaust device with a valve. In the figure, 1 is a base cylinder, 2 is a rotating shaft that also holds the cylinder, 3 is a rotation motor, 4 is a coating liquid beam, 5 is a gun, 6 is a pedestal for the horizontal feed mechanism, 7 is a paint outlet pipe, 8 is a filter, 9 10 is a paint tank, 10 is an air vibrator, 11 is a pressure gauge, 12 is a nozzle tip, 13 is a hood, 14 is a paint film in a leveling state, 15 is a paint film in a state before leveling, 16 is a slit-shaped opening in the hood Department,
17 is a forced exhaust pipe, and 18 is a forced exhaust valve. Agent Patent Attorney Seki Yamashita Figure (b) Figure (C) Figure! Figure (d) ＼ Nigo==" Figure Co) Figure (b)

Claims (1)

[Claims] 1. Substantially applying a paint for forming an electrophotographic photoreceptor onto the surface of the support for an electrophotographic photoreceptor or onto a coating layer on the surface from a paint discharging gun having minute openings. In a method for manufacturing an electrophotographic photoreceptor, which includes discharging without atomizing to form a liquid coating film, and then drying the coating liquid film to the touch, the method includes discharging the coating material without atomizing it, forming a coating liquid film, and then drying the coating liquid film to the touch. 1. A method for drying a coating layer of an electrophotographic photoreceptor to the touch, the method comprising: enclosing solvent vapor generated from the coating liquid film around the coating liquid film. 2. The touch drying method according to claim 1, further comprising exhausting the enclosed atmosphere at a constant air volume after a predetermined period of time. 3. The touch drying method according to claim 2, further comprising the step of providing a valve at a portion of the exhaust pipe to open the exhaust pipe.