JPH01189367A - Coating device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a coating device that forms an extremely homogeneous coating film on the surface of a cylindrical substrate, for example, a coating device that forms a paint-like or solution-like coating on a cylindrical conductive substrate. The present invention relates to a coating device used for manufacturing electrophotographic photoreceptors by coating a material extremely uniformly to form a photosensitive layer.

[Conventional technology]

Conventionally, many means are known for applying a coating material to a cylindrical substrate to form a coating. For example, there is a dipping method in which a coating liquid is filled in a coating liquid tank, a cylindrical substrate is immersed in this coating liquid, and then the substrate is pulled up and dried to form a coating film, or a cylindrical substrate is rotated and during this rotation The spray method involves spraying a coating solution onto the paint to form a coating film.

These coating methods are effective methods for forming a coating on a cylindrical substrate. However, it is difficult to obtain a highly homogeneous film or a film of extremely uniform thickness using such a method. For example, when a coating film is formed on a cylindrical substrate by a dipping method, if the same coating solution is reused, the degree of contamination with impurities increases accordingly. Furthermore, there is a strong possibility that thickness unevenness may occur due to so-called dripping of the coating material, and it is difficult to guarantee accuracy for coatings in which variations in film thickness, film quality, etc. within a range of several micrometers are a problem. The above-mentioned factors should be eliminated as much as possible for electrophotographic photoreceptors, which particularly require extremely high precision in terms of film homogeneity and film thickness uniformity.

In order to solve these problems, we use a coating jig equipped with an annular partition wall with a diameter slightly larger than the outer diameter of the cylindrical base and a recess that can store the coating liquid. A method has already been proposed and known in which a film is formed by inserting a cylindrical substrate, pouring the necessary amount of coating liquid into the recessed portion each time using a coating liquid supply device, and then pulling up the cylindrical substrate.

[Problem to be solved by the invention]

However, even in this method, if a coating liquid with low viscosity is used, there is a possibility that the liquid may flow downward from the gap between the cylindrical substrate and the coating jig, causing uneven coating. Therefore, the pulling speed of the substrate is increased (this results in a thicker film.Also, when coating a large number of substrates, a large amount of coating liquid must be stored in the coating liquid storage tank of the coating liquid supply device. Generally, a coating liquid is made by dissolving a resin in an organic solvent and dispersing a functional material therein, so if it is left for a long time, its dispersibility deteriorates, which affects the homogeneity of the coating film.

It is difficult to repeatedly apply a coating film that is homogeneous and has a uniform thickness with good reproducibility using the above method.

The present invention eliminates the above-mentioned drawbacks, prevents contamination of the coating solution, reduces the amount of coating solution used, and forms a vertical coating film on a cylindrical substrate with uniform thickness and quality. It is an object of the present invention to provide a coating device capable of forming a coating on a surface.

[Means to solve the problem]

In order to achieve the above object, according to the present invention, in a coating device that forms a coating film on the surface of a cylindrical substrate while lifting the substrate relatively to a coating jig, the substrate is moved at intervals. An annular part that surrounds the base and constitutes the outer wall and bottom of the coating liquid storage part whose inner wall is the base surface, and an elastic material that protrudes from the inner circumferential side of the bottom of the coating liquid storage part so as to be able to slide on the base surface. A coating jig consisting of a coating liquid leakage prevention member, a coating liquid storage tank provided separately from this coating jig, a mechanism for applying ultrasonic vibration to the coating liquid in this tank, and a coating liquid in this tank. The coating apparatus is provided with a coating liquid supply device comprising a mechanism for supplying the coating liquid to the coating liquid reservoir of the coating jig.

[Effect]

While sequentially supplying the required amount of coating liquid to the coating liquid storage section of the coating jig by the coating liquid supply device, the coating liquid is applied to the surface of the cylindrical substrate that constitutes the inner wall of the coating liquid storage section, and the coating liquid is applied to the substrate. A coating film can be formed on the surface of the substrate by pulling it up in the vertical direction relative to the coating jig. As a result, contamination due to reuse of the coating liquid is eliminated, and the amount of coating liquid used can be reduced. In addition, by sliding the substrate surface against the coating liquid leak prevention member provided at the bottom of the coating liquid reservoir, the coating liquid will not leak down the substrate surface, and a coating film with a uniform thickness can be obtained. It will be done. Furthermore, since the coating liquid supplied from the coating liquid supply device can be made homogeneous by being uniformly dispersed by ultrasonic waves in the coating liquid storage tank, a homogeneous coating film can be obtained with good reproducibility. Become.

〔Example〕

FIG. 1 shows an embodiment of the present invention, and is a conceptual sectional view of an apparatus for coating a thin photosensitive layer on a conductive cylindrical substrate of an electrophotographic photoreceptor, in which a cylindrical substrate 1 is coated with a ring-shaped substrate. Application jig 3
The coating jig 3 includes a polymer member 9, for example, a Teflon member, which has a parallel surface facing the coating film forming surface 2, which is formed by vertically positioning the outer surface of the substrate, and is separated by a required constant distance A. 7 and a metal member 1, for example, a stainless steel member 6, to which it is attached, and the upper end of the coating jig 3 has a coating liquid reservoir 8 for receiving the coating liquid 9 supplied from the coating liquid supply device 10. In order to prevent the coating liquid 9 supplied to the coating liquid reservoir 8 from flowing into the annular gap with the interval A and flowing downward, there is a groove on the inner circumferential side of the bottom of the coating liquid reservoir that slides against the base surface. It is held by a seal 5, which is a member that prevents leakage of the coating liquid. Although not shown in FIG. 1, this coating device has a mechanism for lifting the substrate 1 along a concentric axis with the coating jig 3 in the vertical direction shown by the arrow in FIG. A coating film can be formed on the coating film forming surface 2 of the substrate by providing a mechanism for lowering the coating film.

The seal 5 is composed of a circular rubber or plastic sheet with different outer and inner diameters, and is slidably installed in contact with the base surface diagonally upward as shown in Figure 1, with the side in contact with the base being The opposite side is closely fixed to the Teflon member 7, and the coating liquid 9 is stored without leaking downward.

The angle θ between the coating film forming surface 2, which is the substrate surface shown enlarged in FIG. 2, and the seal 5 is preferably an acute angle, preferably in the range of 5 degrees to 70 degrees, and more preferably It ranges from 5 degrees to 50 degrees.

As the material for the seal 5, a material that is not easily affected by organic solvents is selected. For example, silicon-based, fluorine-based,
Chloroprene-based or nitrile-based rubbers, silicone-based, fluorine-based, polyethylene-based, or polypropylene-based resins can be used. Further, the thickness of the seal 5 needs to be strong enough and elastic enough not to damage the surface of the substrate during sliding, and strong enough not to leak the coating liquid.

The thickness of the coating film is determined by the relative moving speed between the substrate I and the coating jig 3 shown in FIG. 1 and the viscosity of the coating liquid. In order to obtain a thin film, it is necessary to slow down this movement speed or to reduce the viscosity of the coating liquid.

In conventional coating apparatuses, when the viscosity of the coating liquid is lowered in an attempt to form a thin film, the coating liquid leaks. In order to prevent this, it is better to narrow the interval, but if the IVJ interval A is narrowed, there is a risk that the coating jig 3 will come into contact with the coating film forming surface 2 and cause damage. Therefore, in order to obtain a thin film, the moving speed must be slowed down, and it is difficult to maintain a constant speed, which tends to cause variations in film thickness.Also, it takes time to coat, which worsens workability. This method has the drawback of increasing the chances of trouble occurring during coating. By providing the seal 5, there are no restrictions on the viscosity of the coating liquid.
A thin film can now be formed without slowing down the movement speed too much, and even a thin film with a thickness of 1 μm or less can be coated uniformly and with good workability.

Further, 10 in FIG. 1 is a coating liquid supply device, in which ultrasonic vibration is applied by a shaft 16 to the coating liquid 9 in the coating liquid storage tank 1'l, which is sealed by a lid 14, so that ultrasonic waves can be constantly dispersed. This allows the coating liquid to be kept homogeneous for a long time. When coating, use this homogeneous coating liquid 9.
By adjusting the valve 13 via the supply pipe 12, the necessary amount is sequentially supplied to the coating liquid reservoir 8 of the coating jig 3.

Specific examples will be described below.

Example 1 A coating liquid having the following composition was applied to the finished outer surface of an Aβ alloy cylindrical substrate having an outer diameter of 6 cm and a length of 30 cm.

β-type copper phthalocyanine 0.5 g Lionol Blue SM (manufactured by Toyo Ink) Polymethyl methacrylate resin 0.25 g (manufactured by Tokyo Kasei) Toluene 25 g Using the coating device shown in Figure 1, the spacing A was 5 mm and B was 10 In.
Nitrile rubber with a thickness of 1 mm was used as the seal 5, and the angle θ with respect to the base was 10 degrees. When the substrate 1 was coated while being pulled up at a speed of 40 mm/sec, a coating film with a uniform thickness of 0.2 μm ± 20% was obtained over the entire length of 30 cm, and the amount of liquid used was 1% of that in the conventional dipping method.
The amount was At this time, 150 W of ultrasonic vibration was applied to the coating liquid 9 in the coating liquid storage tank 11.

Further, when the coating liquid 9 in the tank 11 was left in a state where ultrasonic vibrations were applied and the same coating was performed 24 hours later, an equivalent coating film was obtained.

Example 2 A coating liquid having the following composition was further applied to the outer surface of the cylindrical substrate on which the coating film was formed in Example 1.

■-Phenyl-3-(p-diethylaminostyryl)=
5 ~ (p-diethylaminostyryl)-2-pyrazoline Jg Polymethyl methacrylate resin (manufactured by Tokyo Kasei) 0.2 g Tetrahydrofuran 5 g Using the applicator shown in Figure 1, the spacing was 4 mm, and 2 strokes were applied as seal 5. Thick silicone rubber was used, and the angle θ with respect to the base was 45 degrees. When the substrate was coated while being pulled up at a speed of 3 M/sec, a uniform coating film with a thickness of 20 μm ± 0.5 μm was obtained over the entire length of 30 cm, and the amount of liquid used was 0.1% of that in the conventional dipping method. The amount was During coating film formation, 150 W of ultrasonic vibration was applied to the coating liquid 9 in the storage tank 11.

In addition, when the coating liquid 9 in the storage tank 11 was left in a state where ultrasonic vibration was applied and the same coating was performed 24 hours later,
Equivalent coatings were obtained.

When the product thus produced was used as an electrophotographic photoreceptor, it was found to be sufficiently usable for practical use.

〔Effect of the invention〕

According to the coating apparatus of the present invention, the large amount of extra coating liquid required by the conventional dipping method is no longer required, and the amount of coating liquid used can be significantly reduced.

Moreover, there are no restrictions on the viscosity of the coating solution, and it is possible to form a coating film of a desired thickness uniformly and accurately over a wide range of thicknesses while freely selecting the pulling speed of the substrate. can be formed with good workability, which is highly effective. Furthermore, since new liquid can be continuously supplied in the required amount at all times, there is no need to worry about contamination of the coating liquid. Furthermore, by applying ultrasonic vibration to the coating liquid in the coating liquid storage tank, the coating liquid can be kept homogeneous, and it becomes possible to form a stable coating film over a long period of time with good reproducibility. The coating apparatus of the present invention is particularly effective in forming a photosensitive layer of an electrophotographic photoreceptor, which has strict requirements regarding film quality and film thickness.

[Brief explanation of the drawing]

FIG. 1 is a conceptual sectional view of an embodiment of the coating device of the present invention;
FIG. 2 is a partially enlarged sectional view of a portion of the coating liquid leakage prevention member.

Claims (1)

[Claims] 1) In a coating device that forms a coating film on the surface of a cylindrical substrate while lifting it relative to a coating jig,
Surrounding this base body at intervals, an annular portion that constitutes the outer wall and bottom surface of a coating liquid reservoir whose inner wall is the surface of this base body, and an inner peripheral side of the bottom face of this coating liquid reservoir are slidable on the base surface. A coating jig consisting of a protruding coating liquid leakage prevention member made of an elastic material, a coating liquid storage tank provided separately from the coating jig, and applying ultrasonic vibration to the coating liquid in this tank. A coating device comprising: a mechanism; and a coating liquid supply device comprising a mechanism and a mechanism for supplying the coating liquid from the tank to the coating liquid reservoir of the coating jig.