JP3314464B2 - Method for supplying paint to die coater and apparatus therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for supplying paint to a die coater. In particular, the present invention relates to a paint supply method capable of supplying paint in a constant amount with high accuracy and without generating bubbles in the paint by a pump.

[0002]

2. Description of the Related Art Conventionally, a die coater has been mainly used for thick-film coating or high-viscosity coating due to restrictions on die manufacturing accuracy and control techniques. The paint supplied to the die coater is usually contained in a simple container such as a drum, and a pipe or a hose is inserted from the top of the container, and the paint is pumped up. Therefore, as a paint supply device to the die coater, a simple device in which a die coater and a paint container are connected by a pipe, and a supply pump such as a gear pump and a filter as required are installed in the middle thereof is mainly used. .

[0003]

Recently, a die coater for precision coating has been developed. However, since the supply of paint to such a die coater requires a high quantitative property, quantitative measurement of a usual gear pump or the like is required. A conventional paint supply device using a low-performance pump cannot cope. As a solution to this point, a pump with low self-priming such as a zenith pump etc. but with high quantitative performance and a supply pump with low quantitativeness but self-priming, for example, a diaphragm pump, a snake pump, a gear pump, etc. were used together. There is a paint supply device. One example is shown in FIG. 2, in which the suction side supply pipe 3 from the paint container 1 to the suction end of the metering pump 2 installed at a position lower than the paint liquid level of the paint container 1 and the discharge of the metering pump 2 A suction-side supply pipe 5 extending from the end to the die coater 4, a suction-side work pipe 7 branching from the suction-side supply pipe 3 and reaching a suction end of the supply pump 6,
A discharge-side work pipe 8 extending from the discharge end of the supply pump 6 to the paint container 1, and a communication pipe 9 for connecting the discharge-side supply pipe 5 and the discharge-side work pipe 8 are provided. 10, 11 and 1
2 is a valve installed in each pipe. In addition,
In addition to the above, a supply pipe 14 branching from the suction-side work pipe to reach the supply paint container 13 is provided, and
It is preferable to provide 9 because the paint supply operation can be performed in parallel with the painting operation. The operation of the paint supply device will be described.
The supply pump 6 is operated with the valves 1 and 12 opened and the valve 19 closed. Then, the paint in the paint container 1 is supplied to the suction side supply pipe 3, the suction side work pipe 7 and the discharge side work pipe 8.
And a part thereof is circulated to the paint container 1, a part of which is connected to a suction side supply pipe and a communication pipe 9 downstream of a branch point from the suction side work pipe.
And it flows into the discharge side supply side piping 5. When the paint is filled up to the suction end of the metering pump 2, the supply pump 6 is stopped. Next, when the valves 10 and 11 are closed to operate the metering pump, the paint reaches the suction end of the metering pump 2 from the paint container 1 via the suction side supply pipe by the siphon action, and is sent out by the metering pump 2 to be supplied on the discharge side. It flows through the pipe 5 and is supplied to the die coater 4.

According to this method, the supply of the coating material can be controlled with high accuracy, but there is a problem that the coating liquid level of the coating container 1 decreases with the progress of the coating operation, and therefore the back pressure of the metering pump 2 decreases. . Generally, the height difference between the paint container 1 and the metering pump 2 is not so large due to work restrictions, so that a decrease in the back pressure causes cavitation and bubbles may be generated in the paint. Die coating with a paint containing air bubbles causes defects in the coating film, so generation of air bubbles must be avoided by all means.

[0005] The present invention maintains the high accuracy of the metering pump,
It is another object of the present invention to provide a method of supplying a paint that can reliably avoid the generation of bubbles.

[0006]

According to the present invention, the coating liquid level of the coating container decreases as the coating operation proceeds.
Compensated by tilting or lifting the paint container,
Maintain a constant level of the coating liquid level. As a result, the back pressure of the metering pump 2 is also kept constant, so that the generation of bubbles in the paint can be prevented. In order to keep the coating liquid level constant, it is preferable to tilt the coating container rather than lift it with a jack or the like. Because the distance between the metering pump and the paint container changes with time in the method of lifting with a jack or the like, a long flexible pipe must be used, and the flow rate due to the siphon action is small due to pressure loss in the pipe. Become. The use of a thick pipe to reduce pressure loss has problems in terms of cleaning and handling. Further, since the position of the paint container is increased, various inconveniences are caused in operation.

FIG. 1 is a modified version of the apparatus of FIG. 2 adapted to the present invention. In FIG. 1, the paint container 1 is fixedly mounted on a tilting mechanism 15. The tilting mechanism has a container mounting table 16 that can rotate left and right around a rotation axis, and an arc-shaped guide rail 17. When the container mounting table 16 is rotated along the guide rail, the paint container 1 placed thereon is tilted, and it is possible to compensate for a decrease in the paint liquid level due to the removal of the paint. The operation of the apparatus shown in FIG. 1 will be described. After performing the priming operation as described above, the supply pump 6 is stopped, and the metering pump 2 is operated to perform the painting operation.
As the coating operation progresses, the coating liquid level of the coating container 1 decreases. This is detected by the pressure gauge 18 as a change in the back pressure of the metering pump 2, and the tilting mechanism 15 is operated so that the back pressure is restored to the reference value. And tilt the paint container 1. Although this operation can be performed manually, it is preferable to adopt an automatic control system that receives a signal from the pressure gauge 18 and operates the drive motor of the tilting mechanism based on the signal. The tilting mechanism includes
It is safe to provide a limit switch that defines the upper limit of the tilt so that the paint container does not tilt beyond a certain angle. Further, when the tilt angle of the tilt mechanism reaches a certain value, it is preferable that the supply pump 6 is automatically operated to supply the paint from the supply paint container. When the paint flows into the paint container 1, the pressure detected by the pressure gauge 18 increases, and the tilting mechanism is driven in the reverse direction to return the paint container 1 to the first upright position. For automatic refilling of paint, a limit switch is provided to set the lower limit of the tilt so that the paint does not flow in even after the paint container stands upright. Is preferably stopped automatically. If this tilting mechanism is used, the suction side supply pipe can be a fixed pipe only by making the outlet portion of the paint container flexible. Therefore, since the pressure loss of the pipe is small, a large flow rate can be secured by the siphon action even in a thin pipe, and the pipe can be easily cleaned.

[0008]

According to the present invention, die coating can be performed with extremely high precision, and an excellent coating film can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of one example of a device suitable for practicing the present invention. The omitted parts are the same as those in FIG.

FIG. 2 is an example of an apparatus on which the present invention is based.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 paint container 2 metering pump 3 suction side supply pipe 4 die coater 5 discharge side supply pipe 6 supply pump 7 suction side work pipe 8 discharge side work pipe 9 communication pipe 10 valve 11 valve 12 valve 13 refill paint vessel 14 supply pipe 15 Tilting mechanism 16 Container mounting table 17 Guide rail 18 Pressure gauge 19 Filtration device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B05C 5/02 B05C 11/10 B05D 3/00

Claims (3)

(57) [Claims] 1. A paint container, a metering pump installed at a position lower than the paint level of the paint container, a suction-side supply pipe connecting a suction end of the metering pump to the paint container, and a discharge end of the metering pump. In a method for quantitatively supplying paint to the die coater using a paint supply device having a discharge side supply pipe connecting the die coater, by tilting or rising the paint container in accordance with the removal of the paint from the paint container,
A method comprising maintaining the suction end pressure of a metering pump constant. 2. A paint container, a tilting mechanism for placing and tilting the paint container, a metering pump installed at a position lower than the paint level of the paint container, and connecting a suction end of the metering pump to the paint container. An apparatus for supplying paint to a die coater, comprising: a suction-side supply pipe, a discharge-side supply pipe connecting a discharge end of a metering pump and a die coater, and control means for a tilting mechanism. 3. The tilting mechanism according to claim 2, wherein the control means of the tilting mechanism detects the pressure at the suction end of the metering pump and tilts the tilting mechanism so as to maintain this pressure constant. Feeding device.