JP2000343020A - Method for preventing drying of coating head slit tip part and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for completely prevent the drying of a coating slit tip part in a die coating system and a automated device therefor. SOLUTION: In a die coating system, the method for preventing the drying by forming a liquid film from the coating liquid at the head tip to eliminate the contact of the liquid with air at the slit tip part is provided and the device possesses a table for forming the liquid film and a structure for sucking the formed liquid film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing a coating head slit end portion (hereinafter referred to as a slit end portion) from drying in a die coating method, for example.

[0002]

2. Description of the Related Art In a coating process using a die coating method, a head is often forced to stand by due to a failure in a process or a stop due to a mechanical trouble. At that time, problems such as generation of foreign matter due to drying of the slit tip portion (see FIG. 1) and obstruction of liquid ejection are caused. Conventional slit tip drying prevention methods include a method using a head cover and a method using a pad filled with a solvent to create an atmosphere.However, there is contact between liquid and air at the slit tip, so drying is completely prevented. It can not be said. Therefore, especially for a liquid having a high drying rate, it is necessary to manually wipe the tip of the head with a cloth impregnated with a cleaning liquid during standby for a long time. However, in such a conventional method,
Work efficiency is very poor.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for completely preventing drying of a slit tip and an automatic apparatus for the method. is there.

[0004]

SUMMARY OF THE INVENTION In a die coating method, a method for preventing drying by forming a liquid film of a coating liquid at the tip of a head and eliminating contact between the liquid and air at the tip of a slit, and an apparatus therefor include the following. And (a) a base for forming a liquid film; (b) a mechanism for sucking the formed liquid film; and (d) preventing drying of the slit tip portion comprising (a) to (b). apparatus.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method described in claim 1 will be specifically described. As shown on the left side of FIG. 2, drying at the tip of the slit causes problems such as generation of foreign matter and obstruction of liquid ejection. Therefore, as shown on the right side of FIG. 2, an appropriate gap is provided immediately below the head slit, a simple table is provided, and a liquid film is forcibly formed to prevent drying of this portion.

In the second aspect, (a) and (b) function as follows. (A) A stage for forcibly forming a liquid film as described above (see FIG. 2), which has an effect of preventing drying of the slit tip. Accordingly, it is possible to prevent the generation of foreign matter and the hindrance of the liquid ejection in this portion before drying. (B) A device for sucking the liquid film forcibly formed by (a), whereby contamination of the head and the table by the liquid film can be prevented.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method and an apparatus for preventing drying of the slit tip will be described below in more detail with reference to the drawings. The present embodiment relates to a liquid film forming table using a flat bar and a forming liquid film removing mechanism by air suction.

First, the configuration of the apparatus will be briefly described. Reference numeral 7 in FIG. 3 denotes a liquid film forming table, which is shown in more detail in FIG. Since the liquid film forming table (7 in FIG. 3) is located at a fixed distance from the head tip, the coating liquid discharged from the coating head (6 in FIG. 3) is forcibly forced by the surface tension of the table. It becomes a film. This makes it possible to prevent drying of the slit tip. The surface of the base is coated with Teflon (see FIG. 4) to make it easy to remove the liquid, and has a water repellency.

Reference numeral 5 in FIG. 3 denotes a suction nozzle for removing the formed liquid film. The liquid is sucked by a vacuum ejector 1 and its control is performed by opening and closing an air operated valve 2. The suctioned liquid is discharged by opening the switching valve 4 to the air pressurizing side. The pipe between 4 and 5 needs to be long enough so that the sucked liquid does not flow upstream (vacuum ejector) of the switching valve of 4. Further, in order to periodically clean the nozzles and the pipes, the switching valve 3 is opened to the pressurized tank side 8 for every predetermined tact to discharge the cleaning liquid. FIG. 5 shows the drive mechanism of the suction nozzle in detail. The air cylinder 11 in FIG. 5 drives the suction nozzle in the head coating direction. The air actuator 12 rotates the suction nozzle in a direction perpendicular to the ground when discharging the suction liquid and the cleaning liquid. The air cylinder 13 drives the nozzle in the vertical direction.

Next, the operation procedure will be described. After coating, the head (6 in Fig. 3) is a liquid film forming platform
(7 in FIG. 3 and 16 in FIG. 5) Wait until the next coating starts. At that time, a small amount of liquid is discharged to form a liquid film.

When the head is moved to enter the next coating after the head standby is completed, the suction nozzles (5 in FIG. 3 and 15 in FIG. 5) at the standby position as shown by the dotted line on the right side of FIG. 5 air cylinders (11 in FIG. 5, FIG. 5)
It moves to the liquid suction position by the driving of 13).

When the air operated valve (2 in FIG. 3) is opened, the vacuum ejector operates and the liquid is sucked. When completely sucked, close the air operated valve. In this embodiment, the suction operation is performed after the head is moved. However, the suction operation can be performed while the head is on standby.

The suction nozzle is returned to the standby position by the two air cylinders, and further rotated by the actuator (12 in FIG. 5) to move to the suction liquid discharge position.

The suction liquid is discharged by opening the switching valve (4 in FIG. 3) to the air pressurizing side. When the discharge is over, switch the valve again.

If necessary, the switching valve (3 in FIG. 3) is opened to discharge the cleaning liquid, thereby cleaning the inside of the pipe and the nozzle.

The suction nozzle is rotated again by the actuator, and returns to the original standby position. This ends a series of operations.

If it is necessary to form a liquid film for a long time due to, for example, a mechanical trouble, it is possible to control so that the liquid is sucked and discharged at regular time intervals and a liquid film is formed again. is there.

[0018]

As described above in detail, according to the method and apparatus for preventing drying of the slit tip according to the present invention, the following effects can be obtained. That is,
By forcibly applying a liquid to the tip of the head using a liquid film forming table, drying of the tip of the slit could be prevented, and the generation of foreign matter due to drying could be reduced. The problem caused by the clogging of the slit liquid has been eliminated even during a long standby. The automation increased work efficiency and improved productivity. That is, it was possible to provide a method and an apparatus for preventing drying of the slit tip portion which are the object of the present invention.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a dry portion of a slit tip in a conventional technique.

FIG. 2 is an explanatory view showing a method for preventing drying of a slit tip portion according to the present invention.

FIG. 3 is a schematic view of a unit of a device for preventing drying of a slit tip portion according to the present invention.

FIG. 4 is a view showing a liquid film formation by a liquid film forming table and a coating head in the apparatus for preventing drying of a slit tip portion according to the present invention.

FIG. 5 is a view showing the structure of a suction nozzle in the slit tip drying prevention device according to the present invention in detail.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vacuum ejector 2 ... Air operated valve 3 ... Switching valve 4 ... Switching valve 5 ... Suction nozzle 6 ... Coating head 7 ... Liquid film forming stand 8 ... Addition Pressure tank 11 ... Air cylinder 12 ... Air actuator 13 ... Air cylinder 14 ... Coating head 15 ... Suction nozzle 16 ... Liquid film forming table

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Claims (2)

[Claims] 1. A method for preventing drying at the tip of a coating head slit in a die coating method by forming a liquid film by a coating liquid on the tip of a head. 2. A device and a mechanism for preventing drying at the tip of a coating head slit in a die coating method as follows: (a) a platform for forming a liquid film; and (b) a mechanism for sucking the formed liquid film. A coating head slit tip drying prevention device, comprising: (a) and (b).