JPH0459947B2 - - Google Patents

Description

[Detailed description of the invention]

(A) Industrial Application Field The present invention relates to a coating device for applying a coating liquid to a continuously running web for producing coated printing paper, carbonless paper, and other coated materials. . (B) Conventional technology A conventional coating device using an air knife applies an excessive amount of coating liquid to the continuously running web surface using a coating method such as a roll method, a dip method, or a fountain method. The method used is to blow it off with an air jet and measure it to the desired amount of coating, but in recent years, as coating devices have become wider and faster, large amounts of high-pressure air are used to spray excessive amounts of coating liquid. It is becoming necessary to remove it. In this case, in order to make the coating amount uniform in the width direction, a method is adopted in which high pressure air is introduced from both sides of the air knife body to achieve uniform blowout in the width direction. (C) Problems to be Solved by the Invention However, in a coating device using an air knife, during wide-width, high-speed coating as described above, high-pressure air entering from both sides of the air knife body collides at the center of the body. As a result, turbulence occurs in the air blown from the center of the air knife, causing liquid streaks on the coated surface. This results in deterioration in the quality and yield of the coated product, and further increases the time required for inspection. An object of the present invention is to prevent air turbulence at an air knife outlet, thereby improving quality, yield, and work efficiency. (D) Means for solving the problem That is, the present invention applies coating liquid 3 to the web 1 that is continuously running in an amount in excess of a predetermined coating amount, and then applies this excess coating liquid 3 to the body. The lip width formed by the body 8 and the upper blade 12 is adjusted using the upper blade adjustment screw 14.The air knife 4 has air intake ports 9 on both sides of the air knife 8, and the lip width formed by the upper blade 12 is adjusted using the upper blade adjustment screw 14.The air knife 4 is used to measure the amount of application to a predetermined amount. In the coating device, the air knife body 8
The present invention relates to a coating device characterized in that a rectifying plate 11 having an opening 10 with an opening ratio of 40% or less is provided on the lip 15 side of the upper blade adjustment screw 14. (E) Examples The present invention will be described in more detail below based on the drawings. FIG. 1 shows an embodiment of the present invention, in which a web 1 to be wound up on an unwind stand 7 is pulled out and an overcoated web 1 is overcoated with a coating liquid 3 by an applicator roll 2. 1' runs along the surface of the backup roll 5. This excess coating liquid is blown off by an air jet from the air knife 4 to measure the coating amount to a predetermined amount. FIG. 2 is an enlarged sectional view of the air knife 4.
There are air intake ports 9 on both sides of the body 8,
It is connected to air piping 6. The upper blade 12 is attached to the body 8 by an upper blade attachment screw 13, and the width of the lip 15 is adjusted by an upper blade adjustment screw 14.
Although the upper blade adjustment screw 14 is used to attach the upper blade, the present invention is not limited to this, and the upper blade 12 or the body 8 may be attached to the upper blade 12 or the body 8 by other means. In this case as well, the direction of the bent portion for installation may be either inside or outside, but the installation must be done in such a way as not to cause turbulence in the air flow. Further, it is preferable to mount the rectifying plate 10 by a method that allows adjustment of the mounting position, for example, by making the shape of the mounting hole into an elongated hole type. Furthermore, it is preferable that the current plate 10 be attached to the upper blade 12 or the body 8 so that there is no gap between them, and a situation where vibration occurs is not preferable. It is desirable to install the current plate 10 closer to the lip 15 than the upper blade adjustment screw 14. This is because the turbulence that occurs when the air supplied from both sides of the body 8 collides in the center is caused by the current plate 10. However, the air that has been rectified by the upper blade adjustment screw 14 may become turbulent again. 3 and 4 are a sectional view and a front view of the current plate 10, respectively. It is desirable that the aperture ratio of the current plate 10 is about 40% or less.
If the aperture ratio is too large, the chamber effect within the body 8 partitioned by the current plate 10 cannot be obtained.
The shape of the opening 11 is preferably circular or elliptical, and the hole diameter, pitch, and plate thickness should be selected appropriately based on the aperture ratio. However, extremely small aperture ratios will increase the flow velocity and cause turbulence. This is not preferable because it causes liquid streaks. (F) Examples Next, the present invention will be further explained by examples. An air knife-width rectifying plate with four holes of 5 mm diameter drilled in a staggered pattern at 8 mm pitch was installed on the lip side of the body using the upper blade adjustment screw, and the speed was 300 m/min.
min, blower pressure 3600mmAq, 4100mmAq,
Air knife coated with art paper coating fluid.
Table 1 shows the results of liquid streaks generated per 150 m of coated paper. For comparison, the coating liquid for art paper was coated under the same conditions using an air knife coater without a rectifying plate, and the results are shown in Table 1. When the current plate was not provided, many liquid streaks occurred in the center of the paper, but when the current plate was provided, no liquid streaks occurred at all.

[Table] (F) Effects of the Invention According to the coating device of the present invention, the generation of liquid streaks that occur when coating liquid on printing coated paper, carbonless paper, and other coating materials can be prevented. , it is possible to improve the quality of the coated material, the yield rate, and the work efficiency.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one embodiment of the present invention, and FIG.
The figure is a sectional view of the air knife coater, FIG. 3 is a sectional view of the current plate, and FIG. 4 is a front view of the current plate. 1... Web, 3... Coating liquid, 4... Air knife, 8... Air knife body, 10... Current plate,
11...Opening.

Claims (1)

[Claims] 1. Coating liquid 3 is applied to the continuously running web 1 in an amount in excess of a predetermined coating amount, and this excess coating liquid 3 is transferred to the body 8 which has air intake ports 9 on both sides of the body 8. In a coating device that measures a predetermined coating amount using an air knife 4 that adjusts the lip width formed by the upper blade 12 using an upper blade adjustment screw 14, the upper blade adjustment screw 14 in the air knife body 8 is used. A coating device characterized in that a current plate 11 having an opening 10 with an aperture ratio of 40% or less is provided on the lip 15 side.