JP2569600B2 - Cylindrical substrate coating apparatus and cylindrical substrate coating method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a coating apparatus and a coating method for coating a photosensitive coating solution on a cylindrical substrate.

2. Description of the Related Art Conventionally, various organic and inorganic materials have been used as photoreceptor forming materials. In particular, an organic photoreceptor formed by dispersing an organic material in a binder resin is excellent in manufacturing cost. Has attracted attention as a photoconductor. Such a photoreceptor is usually produced by dissolving or dispersing an organic photoconductive material together with a resin in an organic solvent to prepare a photosensitive solution, applying the photosensitive solution on a conductive substrate, and drying.

Known methods for forming the photosensitive layer include spray coating, roll coating, blade coating, and dip coating. Among these, a dip coating method in which a cylindrical substrate is immersed in a photosensitive solution and coated is excellent in terms of productivity and manufacturing cost, and is implemented as a method for manufacturing an organic photoconductor.

In recent years, a charge generation material dispersed in a binder on a function-separated type photoreceptor, for example, a conductive substrate, and a charge generation layer coated to a thickness of 0.05 to 1 μm, and a charge transport material in the binder, Many photoconductors have been manufactured in which a charge transport layer dispersed and applied to a thickness of 5 to 30 μm is sequentially laminated. This is because the charge generation layer and the charge transport layer can be individually selected by making the photoreceptor a function-separated type structure, and its characteristics (sensitivity, spectral sensitivity, charging ability, durability, etc.) are arbitrarily changed. This is because there is an advantage that it can be performed.

As described above, a function-separated type photosensitive member that can select characteristics suitable for the purpose and a single-layer type organic photosensitive member that can be produced at low cost are widely used.

Problems to be Solved by the Invention However, when the function-separated type photoreceptor is formed by the above-described dip coating method, the photoreceptor, particularly the charge generation layer, is not used.
When a thin film having a thickness of μm or less is coated on a cylindrical substrate, the following problems become remarkable.

That is, when the cylindrical substrate is immersed, bubbles and aggregates are apt to adhere to the substrate, so that defects such as pinholes are easily generated in the coating layer. In addition, when the substrate is lifted, the coating liquid tends to sag in the vertical direction, resulting in uneven coating and unevenness of the resulting coating layer, and a large difference in thickness (uneven thickness) of the coating layer. Such a problem often occurs not only when a thin film is applied but also when a relatively thick film such as a charge transport layer or a single-layer photosensitive layer is applied.

Therefore, the present invention solves the above-mentioned problems in the production of the coating layer, and is also applicable to the production of a relatively thick coating film such as a thin film such as a charge generation layer and a charge transport layer or a single-layer photosensitive layer. It is an object of the present invention to provide a coating apparatus and a coating method capable of forming a good coating layer.

Means for Solving the Problems That is, the present invention has been described in order to achieve the above-described object.
A cylindrical substrate coating apparatus is provided with an immersion tank containing a photosensitive coating liquid, in which the cylindrical substrate is immersed in the immersion tank, and then the substrate is pulled up from the coating liquid and applied to the surface of the substrate. A cylindrical substrate coating apparatus, comprising: a circumferential flow generating means for spraying a coating liquid from a plurality of supply ports along an inner wall of an immersion tank to generate a circumferential flow of the coating liquid on the peripheral surface of the substrate. It is. Further, the present invention provides a method for spraying a photosensitive coating liquid from a plurality of supply ports provided in a lower part of an immersion tank along the inner wall of the immersion tank, thereby forming a coating liquid on the peripheral surface of a cylindrical substrate immersed in the coating liquid. The present invention relates to a method for coating a cylindrical substrate, which comprises forming a coating layer on the surface of a substrate by generating a circumferential flow and then lifting the substrate from a coating solution.

The cylindrical substrate coating apparatus of the present invention is provided with a circumferential flow generating means in the lower part of the immersion tank, and generates the circumferential flow as an upward flow along the inner wall of the immersion tank, thereby improving the agitating property of the coating liquid. It prevents bubbles and aggregates from adhering when the cylindrical substrate is immersed, and prevents the coating solution from dripping in the vertical direction when the substrate is pulled up.

Examples Hereinafter, the present invention will be described based on examples.

FIG. 1 shows a first embodiment of a cylindrical substrate coating apparatus according to the present invention.

The immersion tank (2) is a cylindrical container, and the inside thereof is filled with a photosensitive coating liquid (3) for coating on a cylindrical substrate. As the photosensitive coating liquid (3), a liquid prepared by dispersing or dissolving a photoconductive substance together with a binder resin in an organic solvent is used.

An overflow receiver (4) is formed concentrically around the outer periphery of the immersion tank (2), and a discharge port (7) is provided at the bottom of the overflow receiver (4) to form a pipe (6).
Connected to the pump (8). On the other hand, a nozzle (5) for supplying the photosensitive coating liquid (3) is provided at a lower portion in the immersion tank, and the nozzle (5) is connected to the photosensitive coating liquid (3) through a pipe (6). It is connected to a valve (10) for adjusting the flow rate of the liquid, a filter (9) for removing foreign substances in the coating liquid, and a pump (8).

The nozzle (5) is composed of a substantially S-shaped pipe as shown in FIGS. 2 (a) and 2 (b), and a coating liquid supply port (11) is formed at both ends. The coating liquid is sprayed from the supply port (11) and flows along the inner wall of the cylindrical immersion tank to generate a circumferential flow. Further, since the nozzle (5) is provided at the lower part of the immersion tank (2), by continuously supplying the coating liquid from the supply port (11), the nozzle is upwardly coupled with the circumferential flow. Produces a flow to As a result, the cylindrical substrate (1)
Circumferential flow is generated along the entire peripheral surface of the immersion tank, thereby improving the vertical agitation in the immersion tank.

A plurality of supply ports are provided at equal intervals and the supply ports are cylindrical, as in the nozzle having the above-described configuration used in the present embodiment or the nozzle of the embodiment shown in FIGS. 2 (c) and 2 (d). By disposing the coating liquid in the tangential direction of the inner wall of the immersion tank, it is possible to effectively generate a circumferential flow of the coating liquid.

Further, as long as the supply port (11) is arranged so as to cause a flow in the circumferential direction, the opening angle of the supply port (11), the shape of the nozzle (5), and the like are not particularly limited.

According to the coating apparatus of the present embodiment, the photosensitive coating liquid (3) is filtered by a filter (9) through a pipe (6) by a pump (8) to remove dust, and the flow rate is adjusted by a valve (10). It is supplied into the immersion tank (2) from a supply port (11) provided in the nozzle (5). Since the nozzle (5) and the supply port (11) provided in the nozzle (5) have the above-described configuration, when the photosensitive coating liquid (3) flows in from the supply port (11), the circumferential direction is increased. Flow occurs. The flow rate of the coating liquid flowing from the supply port needs to be changed depending on the viscosity of the coating liquid, the coating film thickness or the drying temperature, but is preferably 0.01 / min to 5 / min, more preferably 0.05 / min to
2 / min. If the flow rate is less than 0.01 / min, the flow in the circumferential direction cannot be generated effectively and 5 / min
If the amount is larger, air bubbles are generated in the coating liquid or noise is generated in the coating film.

FIG. 3 is a perspective view of the immersion tank and the overflow receiving portion, showing the flow of the photosensitive coating liquid (3) in the immersion tank (2). As described above, the photosensitive coating liquid (3) flows in the circumferential direction (the direction of arrow a) of the cylindrical substrate (1). After the cylindrical substrate (1) is immersed in the immersion tank (2), the photosensitive coating liquid (3) overflows from the immersion tank (2) and flows out to the overflow receiver (4). (Arrow b). The photosensitive coating liquid (3) that has flowed out is overflowed (4).
Is returned to the pump (8) through a pipe (6) from a discharge port (7) provided at the bottom of the nozzle (5) through a filter (9) and a valve (10) by the power of the pump (8). From the immersion tank.

4 and 5 show a second embodiment of the cylindrical substrate coating apparatus according to the present invention, which is substantially the same as FIG. 1 except that a supply port is provided at the lower portion of the inner wall of the immersion tank instead of the nozzle (5). It is similar to the coating device shown.

This coating apparatus is provided with one supply port for supplying the photosensitive coating liquid (3) into the immersion tank (2) on the bottom surface and two supply ports on the wall surface. The supply ports (12) and (14) provided on the wall surface are installed at the lower part of the cylindrical immersion tank (2) in the same horizontal section. Further, as shown in FIG. 5, the supply ports (12) and (14) are open in the tangential direction of the immersion tank (2), and are installed on the opposite side to the center of the circle.

That is, the photosensitive coating liquid is jetted from the supply ports (12) and (14) along the inner wall of the immersion tank, whereby a circumferential flow of the coating liquid is generated on the peripheral surface of the cylindrical substrate (1). Further, by supplying the photosensitive coating liquid from the supply port (13), an upward flow is generated together with the circumferential flow, and as a result, the circumferential flow is formed along the entire peripheral surface of the cylindrical substrate (1). Occurs. This further improves the up-down agitation in the immersion tank.

By arranging a plurality of supply ports at equal intervals in the same horizontal plane as in the present embodiment, it is possible to effectively generate a flow in the circumferential direction. The configuration is not limited to the above-described configuration, and any configuration may be used as long as it generates a flow in the circumferential direction. For example, the supply ports may not be provided on the same horizontal plane.

Experiment 1. 10 parts by weight of the disazo pigment shown below Polyvinyl butyral resin (BM-1 Sekisui Chemical Co., Ltd.)
10 parts by weight together with 200 parts by weight of cyclohexanone were placed in a ball mill pot and dispersed for 24 hours. The obtained photosensitive coating liquid was diluted with cyclohexanone to adjust the solid component concentration to 5% by weight to prepare a coating liquid.

Next, using the coating apparatus shown in FIG. 1, coating was performed at a lifting speed of 0.5 cm / S while generating a flow (flow rate: 0.1 / min) in the circumferential direction of the cylindrical substrate.

Experiment 2. The coating was performed in the same manner as in Experiment 1, except that the pump was not operated and the circumferential flow of the substrate was not generated.

Experiment 3. Using the coating apparatus shown in Fig. 4, apply the photosensitive coating solution prepared in Experiment 1 in the circumferential direction of the substrate (0.3 / mi).
n), coating was performed on the cylindrical substrate at a lifting speed of 0.5 cm / S.

Results The film thickness unevenness and the coating unevenness of the coated materials obtained in Experiments 1, 2, and 3 were examined.

In the coatings obtained in Experiments 1 and 3, the unevenness of the film thickness was as small as 0.30 ± 0.02 μm in all directions in the vertical and circumferential directions, and a very uniform film was formed. In addition, no coating unevenness was observed, and a good film was formed. In addition, when the coating material obtained in Experiment 2 was examined in the same manner, the film thickness unevenness was as large as 0.30 ± 0.04 μm, and the coating unevenness caused liquid dripping and drying unevenness in the upper portion.

From the above results, it was confirmed that the use of the cylindrical substrate coating apparatus of this example effectively prevented film thickness unevenness and coating unevenness, and provided a good coating film.

Effect of the Invention As described above, according to the present invention, the coating liquid is sprayed along the inner wall of the immersion tank from a plurality of supply ports provided in the lower part of the immersion tank, and the circle of the coating liquid is applied to the peripheral surface of the cylindrical substrate. Since a circumferential flow generating means for generating a circumferential flow is provided, it is possible to obtain a good coating tank without unevenness in film thickness or coating.

[Brief description of the drawings]

FIG. 1 is a view showing a configuration of a coating apparatus according to a first embodiment of the present invention, and FIGS. 2 (a) and 2 (b) are a plan view and a front view showing a nozzle shape of the embodiment, and FIG. (C) and (d)
FIG. 3 is a view showing another form of a nozzle, FIG. 3 is a conceptual view showing a flow of a coating liquid during coating, FIG. 4 is a view showing a configuration of a coating apparatus according to a second embodiment of the present invention, and FIG. The top view of the immersion tank of the example is shown. DESCRIPTION OF SYMBOLS 1 ... The same cylindrical base, 2 ... Immersion tank 3 ... Photosensitive coating liquid, 4 ... Overflow receiving part 5 ... Nozzle, 8 ... Pump 9 ... Filter, 10 ... Valve 11,12,13 , 14 …… Supply port.

Claims (2)

(57) [Claims] 1. A cylindrical substrate coating apparatus comprising a dip tank containing a photosensitive coating liquid, immersing a cylindrical substrate in the dip tank, and then pulling up the substrate from the coating liquid to coat the substrate surface. A plurality of supply ports provided in the inner lower portion, the coating solution is sprayed along the inner wall of the immersion tank, and a circumferential flow generating means for generating a circumferential flow of the coating solution on the peripheral surface of the cylindrical substrate is provided. Cylindrical substrate coating device. 2. The method of claim 1, wherein a photosensitive coating solution is ejected from a plurality of supply ports provided in a lower portion of the inside of the immersion tank along the inner wall of the immersion tank to form a circle of the coating solution on the peripheral surface of the cylindrical substrate immersed in the coating solution. A method for coating a cylindrical substrate, wherein a coating layer is formed on the surface of the substrate by generating a peripheral flow and then pulling up the substrate from the coating liquid.