JP2790440B2 - Non-contact gap control die coater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die coater for applying a coating to a continuously conveyed belt-like base material by a die main body separated by a predetermined gap, and more particularly to a die coater which is ejected from an air nozzle which can advance and retreat integrally with the die main body. Non-contact type gap that keeps the gap between the die body and the band-shaped base material constant regardless of the plate thickness variation of the band-shaped base material by separating the air nozzle from the band-shaped base material by air pressure and controlling the separation distance It relates to a control die coater.

[0002]

2. Description of the Related Art In the coating of a die coater, in order to form a glossy coating surface with a uniform coating thickness on a belt-like substrate, the gap between the tip lip of the die body and the substrate surface is always constant. Need to be maintained. If the band-shaped substrate is a film or aluminum, etc., the fluctuation of the substrate thickness is very small, so after adjusting the above gap to the optimal condition, even if the position of the die body with respect to the backup roll is fixed and the application is continued, The gap is kept almost constant.

[0003] However, when the band-shaped base material is a galvanized steel sheet, the allowable thickness of the sheet according to JIS standard G3302 (for example,
In some cases, ± 60 μm at a plate thickness of 0.6 mm may exceed the proper gap for die coating (20 to 80 μm). Therefore, when the die body is fixed and coated, the gap fluctuates greatly and the die tip lip runs. Damage by contact with galvanized steel sheet. Particularly, when the primer coating is applied in a single layer and the two layers are coated thinly, the optimum gap is about 10 to 30 μm. Therefore, it is difficult to apply the coating to the galvanized steel sheet while fixing the die body.

In order to enable die coating on a galvanized steel sheet, the applicant of the present invention has proposed a nip roll type die coater 41 shown in FIG. 4 in Japanese Patent Application No. 6-193657. In this nip roll type die coater 41,
A support base 42 that can advance and retreat with respect to the backup roll 100 on the rail 45; a die body 44 that faces a band-shaped substrate W supported by the backup roll 100 and is continuously transported with a predetermined gap therebetween; A nip roll 43 that rotates while sandwiching the band-shaped base material W between the backup roll 100 and the backup roll 100 is provided. Further, a cylinder rod 47 extending from an air cylinder 46 is connected to the support base 42, whereby the nip roll 43 is urged against the band-shaped base material W. The die main body 44 and the nip roll 43 are arranged such that their respective center lines Y and Z make an equal angle θ with respect to a horizontal line X passing from the support base 42 to the backup roll center axis 101.

In the nip roll type die coater 41 having the above-described structure, if there is a change in the thickness of the belt-shaped base material W to be conveyed, the nip roll 43 and the support table 42 move forward and backward with respect to the backup roll 100. At the same time, the die body 44 advances and retreats by the same amount, and the gap between the tip lip portion 44a and the band-shaped base material W is maintained substantially constant in the initially set state. This makes it possible to apply a die coater to a galvanized steel sheet having a thickness variation of about several tens of μm.

[0006]

However, since the nip roll 43 is in contact with the strip-shaped substrate W, the nip roll 4
If dust or paint adheres to the outer periphery of 3, the gap changes due to the influence. For this reason, it is necessary to scrape off the nip roll 43 with a doctor blade (not shown) as a treatment when dust or the like adheres to the nip roll 43. Also,
At the time of resetting the gap in accordance with the change of the coating specification, it is necessary to manually adjust the position of the die main body 44 with respect to the support table 42, which is troublesome.

Accordingly, an object of the present invention is to move the die body to and from the backup roll in accordance with a change in the thickness of the band-shaped substrate while maintaining a non-contact state without using a contact member with the band-shaped substrate. An object of the present invention is to provide a non-contact gap control die coater for controlling a gap to be constant.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a die body for discharging a paint from a tip lip portion facing a continuously conveyed belt-like substrate with a predetermined gap therebetween. An air nozzle box having a tip nozzle portion that opens along the surface of the base material on the upstream side of the die base material conveyance direction along the base material so as to be integrally movable with respect to the band base material, and a blower connected to the air nozzle box The air nozzle box is separated from the band-shaped base material by the air pressure ejected from the tip nozzle portion,
A balance adjusting mechanism for mechanically balancing the air pressure and the paint discharge pressure is provided so as to control the separation distance to a constant value.

In addition, a non-contact distance meter for measuring a distance to a strip-shaped substrate is installed in the air nozzle box on the non-contact gap control die coater, and a gap between the die body and the strip-shaped substrate obtained from the measured value is measured. A control device may be provided to control the separation distance by changing the rotation speed of the blower so that can be set arbitrarily.

Further, the separation distance may be increased by the balance adjusting mechanism or the control device based on a joining signal or an abnormal signal from a previous step.

[0011]

In the non-contact type gap control die coater according to the present invention (claim 1), the air nozzle box separates from the strip-shaped substrate due to the pressure of the air jetted from the tip nozzle portion. This separation distance is kept constant by mechanically balancing the air pressure and the paint discharge pressure by the balance adjustment mechanism. In this state, when the plate thickness changing portion of the band-shaped member comes to the position facing the tip nozzle portion, the air nozzle box moves forward and backward in accordance with the plate thickness change amount so as to keep the separation distance constant. Thereby, the gap between the tip lip portion of the die body that advances and retreats integrally with the air nozzle box and the band-shaped substrate is controlled to be constant in the initial setting state regardless of the change in the plate thickness.

As described above, according to the present invention, in which the gap is controlled while maintaining the non-contact state with the band-shaped member, the die body follows the thickness change of the band-shaped substrate by using the contact member such as a nip roll. In this case, the gap does not change due to the adhesion of dust or paint as in the case of the above-described case, stable gap control can be performed, and the occurrence of coating defects can be reduced.

According to a non-contact gap control die coater provided with a non-contact distance meter and a control device,
The gap can be arbitrarily set by controlling the separation distance by the control device. Therefore, it is possible to easily and quickly reset the gap in accordance with the change of the application condition, and it is possible to save labor and shorten the operation time.

Further, according to a non-contact type gap control die coater in which the separation distance is increased by a balance adjusting mechanism or a control device based on a splicing signal from a previous step, etc. The retracting operation of the die body can also be performed by the controller and the control device, so that there is no need to separately provide a mechanism dedicated to the retracting operation.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG.
The non-contact gap control die coater 1 according to the present invention comprises:
A die body 2 is provided on the upper part. The tip lip portion 2a of the die body 2 is opposed to a belt-shaped base material W supported by a backup roll 100 rotating in the direction of arrow a and continuously conveyed with a predetermined gap g. The die body 2 is placed on a die set table 3 extending in the coating width direction, and its position is fixed by fixing screws 4. On the other hand, loosening the fixing screw 4 and rotating the gap adjusting screw 5
The die body 2 is moved up and down, so that the die set table 3
And the gap g can be adjusted.

Below the tip lip portion 2a of the die body 2, a groove-shaped paint gutter 10 is arranged along the width direction of the band-shaped base material W. The paint gutter 10 collects paint flowing down from the tip lip portion 2a and, as described later, air blown upward from the curved nozzle portion 16 causes the strip-shaped substrate W
Between the film and the coating film.

Both ends of the die set table 3 in the coating width direction are fixed on saddle hardware 7 respectively. The saddle hardware 7 is installed on a linear rail 8 laid on a base table 9 via a linear bearing (not shown).
The back-and-forth roll 100 can be advanced and retreated in the horizontal direction with almost no resistance. A pulley 11 is rotatably supported on the backup roll 100 side of the base 9. One end of a wire 12 hung on the pulley 11 is connected to the saddle hardware 7, and the other end is connected to a balance weight 13. The balance weight 13 is adjustable in weight and functions as a balance adjusting mechanism, but may be replaced by a coil spring or the like capable of adjusting the pulling force. The linear rail 8 may be inclined at an angle so that the die set table 3 and the saddle metal 7 move in an inclined direction other than the horizontal direction. For example, if the linear rail 8 is tilted so that the saddle metal 7 moves from a diagonally upper direction to the backup roll 100, gravity of the die set table 3 or the like acts, so that the weight of the balance weight 13 is reduced ( Or omission).

As shown in FIG. 2, an air nozzle box 15 is fixed to a lower portion of the die set table 3, and when the saddle metal 7 moves on the linear rail 8, the die body 2 and the band-shaped base material W They move forward and backward as one.

The air nozzle box 15 is formed of a box having an appropriate length in the coating width direction, and has an opening at the tip thereof along the surface of the belt-shaped substrate W on the upstream side of the die body 2 in the transport direction. Curved nozzle part (tip nozzle part) 1
6 are formed. The curved nozzle portion 16 has a curvature substantially equal to the surface of the backup roll 100, and is formed such that there is almost no gap when the nozzle is brought close to the belt-shaped substrate W. In the air nozzle box 15 of the present embodiment, the curved nozzle portion 16 having the same curvature is used to conform to the surface of the band-shaped base material W supported by the backup roll 100. In the case of facing the base material W, a tip nozzle portion that opens in a planar shape that is easy to manufacture may be used.

As shown in FIG. 3, the inside of the air nozzle box 15 is formed of a duct header 17 communicating with the entire width thereof, and a plurality of nozzle chambers 18 divided in the width direction by partition walls 19. Duct header 17
A distribution damper 20 is provided between the nozzle chamber 18 and the nozzle chamber 18. When the damper lever 21 (see FIG. 2) opens and closes the distribution damper 20, the nozzle chamber 18 into which air flows in according to the width of the base material.
You can choose. In addition, curved surface nozzle section 1
The labyrinth seal 2 is provided on both sides of the partition wall 19 facing the 6.
6 is pasted. When the plate thickness changes by switching the type of the band-shaped substrate W, the curvature of the substrate surface slightly changes,
Accordingly, the gap between the nozzle and the curved nozzle portion 16 also changes. Therefore, the labyrinth seal 26 increases the air resistance in the gap, thereby minimizing the outflow of air in the application width direction. By providing the distribution damper 20 and the labyrinth seal 26 in this manner, air can be easily blown out from between the upper and lower edges of the curved nozzle portion 16 in which the gap is formed stably in a straight line and the band-shaped substrate W. Thus, the fluctuation of the air outflow amount due to the change in the plate width and the plate thickness of the base material W is reduced.

It is preferable that the internal volume of the air nozzle box 15 be as large as possible in order to prevent a sudden pressure fluctuation due to a change in the amount of air flowing out from the curved nozzle portion 16. In order to minimize the change in the curvature of the surface of the base material W due to the change in the thickness of the base material W, the backup roll 1
It is preferable to use a material having a diameter as large as possible.

As shown in FIG. 2, the curved surface nozzle portion 16
With respect to a horizontal line X extending along the moving direction of the air nozzle box 15 and passing through the central axis 101 of the backup roll 100, the tip line lip portion 2a of the die body 2 has substantially the same angle (θ ₁
It is formed so that the center part is located at the position forming ≒ θ ₂ ). In the vicinity of the center, a guide roller 25 whose outer peripheral surface is slightly protruded from the curved nozzle portion 16 is rotatably supported. The guide roller 25 prevents the curved nozzle portion 16 from contacting the base material surface even when the air pressure for separating the air nozzle box 15 from the belt-shaped base material W suddenly drops.

An elastic duct 27 is connected to the rear of the air nozzle box 15 so as not to hinder the advance / retreat of the belt-shaped base material W. The duct 27 is connected to the blower 29 via the duct 27 and a service tank 28. . A non-contact distance meter 30 for measuring the distance to the band-shaped substrate W is provided at the upper part of the air nozzle box 15 and at the center in the application width direction, and is electrically connected to a control device 31 which outputs a signal to the blower 29. It is connected to the.

As the blower 29, a turbo fan is preferably used, and the air volume and pressure are variable by controlling the number of revolutions based on an output signal from the control device 31. Also,
The blower 29 is used in a rotational speed region where rotation unevenness is minimized and surging does not occur, and a blower having a large number of impeller blades is selected so as to minimize blow pulsation. Further, the service tank 28 has a function of minimizing the influence of air volume fluctuation due to a change in air volume and pressure of the blower 29 to stabilize air blowing.

The adjustment and coating operation of the non-contact type gap control die coater 1 having the above configuration will be described. First, an optimum value of a gap (hereinafter, simply referred to as “gap”) between the tip lip portion 2a of the die main body 2 and the band-shaped base material W is input to the control device 31. This optimum value differs depending on the coating specifications. For example, when applied to a galvanized steel sheet, a primer film for general building materials with a coating thickness of 10% is wet.
There are various coating specifications in the range of μm to 300 μm of the PVC coating, and the optimum value of the gap in each coating specification is measured by performing a coating test in advance.

Thereafter, the blower 29 is driven to blow air to the air nozzle box 15. The air supplied to the air nozzle box 15 is supplied from the duct header 17 to the distribution damper 20.
Flows into the nozzle chamber 18 in the open state, and the curved nozzle portion 1
6 and presses the strip-shaped substrate W. The air pressure causes the air nozzle box 15 to separate from the strip-shaped base material W.

While the air nozzle box 15 is separated, the strip-shaped base material W is run, and the paint 2 is supplied to the die body 2 from a paint supply device (not shown) via a paint supply hose 14. This hose 14 is also connected to the duct 27
As in the case of (1), a flexible member is used so as not to hinder the forward / backward movement of the die body 2. The paint flowing into the manifold 2b inside the die main body 2 is discharged from the tip lip portion 2a through the slot 2c, and is applied to the belt-shaped base material W. At this time, the paint gutter 10 prevents air spouting upward from the curved nozzle portion 16 from being caught between the belt-shaped base material W and the coating film, and the tip lip portion 2
The paint flowing down from a is collected. Further, the discharge pressure of the paint acts as a reaction force for retracting the die body 2 from the belt-shaped base material W. The balance weight 13 (see FIG. 1) is mechanically balanced to oppose the paint discharge pressure and the air pressure, so that the separation distance between the air nozzle box 15 and the strip-shaped substrate W is kept constant. It is. Note that this separation distance is made as small as possible.
The thickness is preferably not more than 00 μm, whereby the consumption of air volume is reduced, and the power of the blower 29 is reduced.

The separation distance of the air nozzle box 15 is measured by the non-contact distance meter 30, and the measured value is transmitted to the control device 3.
1 is input. The control device 31 calculates the gap by calculating the measured value, and outputs to the blower 29 a signal for changing the rotation speed so that the gap becomes an optimum value. When the gap reaches the optimum value, the control device 31 maintains the rotation speed of the blower 29, whereby the gap is initialized.

The thickness change portion of the band-shaped base material W is a curved nozzle portion 1
6, the air nozzle box 15 advances and retreats with respect to the band-shaped base material W in accordance with the thickness change so as to keep the separation distance constant. At the same time, the die body 2 advances and retreats by the same amount, and the gap is kept substantially constant in the initial setting state regardless of the change in the plate thickness.

As described above, according to the non-contact type gap control die coater 1, since the control for keeping the gap constant while maintaining the non-contact state with the strip-shaped substrate W is performed, a contact member such as a nip roll is used. As in the case where the die body 2 is moved to follow the change in the thickness of the band-shaped base material W, the gap does not change due to adhesion of dust or paint, and stable gap control can be performed.

The die set table 3 supporting the die body 2 and the air nozzle box 15 is supported at both ends by saddle metal members 7 (see FIG. 3), and only the saddle metal member 7 at one end is minute. It is also possible to move. If there is a small change in the thickness of the band-shaped base material W in the coating width direction, the separation gap between the tip nozzle portion 16 and the band-shaped base material W becomes non-uniform in the coating width direction, and the difference in air outflow resistance from this gap is reduced. Occurs. This resistance difference acts as a force to make the separation gap uniform, and the air nozzle box 15
Is moved back and forth along the surface of the belt-shaped substrate W. Thereby, the tip lip portion 2a of the die body 2 is kept parallel to the band-shaped base material W, and the gap can be kept constant even when the plate thickness changes in the application width direction.

Further, when the coating specification is changed, the optimum gap value according to the coating specification in the next process is set by the control unit 31.
Since it is sufficient to set the gap, it is possible to easily and quickly reset the gap.

If the controller 31 increases the rotation speed of the blower 29 to increase the separation distance from the band-shaped base material W based on the splicing signal and the abnormal signal from the previous process, the die body 2 The evacuation operation can be performed, and there is no need to provide a special evacuation operation mechanism.

In the non-contact type gap control die coater 1, the initial setting of the gap and the retreat operation of the die body 2 are performed by changing the rotation speed of the blower 29 by the control device 31. The rotation speed may be kept constant and the weight of the balance weight 13 may be finely adjusted or reduced.

[Brief description of the drawings]

FIG. 1 is a side view of a non-contact type gap control device according to the present invention.

FIG. 2 is a partial longitudinal sectional view of the non-contact type gap control device of FIG.

FIG. 3 is a plan view of the non-contact gap control die coater of FIG. 1 including a partially cutaway portion for showing an internal structure of the air nozzle box.

FIG. 4 is a side view of a nip roll type die coater according to another application of the present applicant.

[Explanation of symbols]

1. Non-contact gap control die coater 2. Die body,
2a: Tip lip, 13: Balance adjustment mechanism, 15 ...
Air nozzle box, 16: curved surface nozzle portion (tip nozzle portion), 29: blower, 31: control device.

Claims (3)

(57) [Claims] 1. A die body for discharging paint from a tip lip facing a continuously transported band-shaped substrate with a predetermined gap therebetween, and along a substrate surface upstream of the die body in the direction of transport of the band-shaped substrate. An air nozzle box having a tip nozzle portion having an opening is provided so as to be integrally movable with respect to the belt-shaped base material, and the air nozzle box is blown through the tip nozzle portion from a blower connected to the air nozzle box to thereby form the air nozzle box. While separating from the belt-shaped substrate,
A non-contact type gap control die coater provided with a balance adjustment mechanism for mechanically balancing the air pressure and the paint discharge pressure so as to control the separation distance to be constant. 2. A non-contact distance meter for measuring a distance to a band-shaped base material is installed in the air nozzle box, and the blower is arranged so that a gap between the die body and the band-shaped base material obtained from the measured value can be arbitrarily set. 2. The non-contact gap control die coater according to claim 1, further comprising a control device for controlling the separation distance by changing a rotation speed of the die. 3. The non-contact gap control according to claim 1, wherein the separation distance is increased by the balance adjustment mechanism or the control device based on a joining signal or an abnormal signal from a previous process. Die coater.