JPH08281183A - Coating machine - Google Patents

Abstract

PURPOSE: To deeply scrape off a coating film applied on a web, to improve the quality of a final finish, and to make maintenance easy. CONSTITUTION: In a coating machine, a taper part 1a is formed on the back side of the end part of a blade 1, and the front side of the end part of the blade 1 with a reverse taper contacts a coating layer closely by the flexibility of this part. Besides, since the relief of the end part of the blade is prevented by the excess thickness part of the back side of the end part of the blade 1, especially by the rigidity of 1a' part, the coating film applied on a web is scraped off deeply, waving and heaving are prevented in this process, and the quality of a final finish improves. By pushing a rear side part, rather than the front end part, of the blade 1 toward the web, the use of more than one pressure tube is made unnecessary, thus facilitating maintenance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention applies a coating solution to a continuously running web and then scrapes off the excess coating solution on the surface of the tip of a blade to form a coating layer on the web. It relates to a coating device.

[0002]

2. Description of the Related Art A coating apparatus applied to a conventional papermaking machine will be described with reference to FIG. 5, which shows a side view of the coating apparatus. A is a front coating section, and B is a rear scraping section. The former coating section A comprises a blade clamp device 2 having a blade 1 and a pressure tube 7 arranged behind the blade 1, and a slit type blowing head 3 supporting the blade clamp device 2. There is.

The scraping section B at the rear stage is equipped with a finishing blade 1 '. 4 is a coating liquid, 5 is a backing roll that rotates in the direction of the arrow, and 6 is a web that runs continuously. In the coating apparatus shown in FIG. 5, when forming a normal coating film, only the coating section A of the preceding stage is used to perform the one-step blade finishing. That is, after the coating liquid 4 is blown out from the slit type blowing head 3 to apply the coating liquid 4 to the web 6 which continuously runs together with the backing roll 5, the surplus coating liquid 4 is applied to the surface of the tip of the blade 1. It is scraped off by the side to form a coating layer on the web 6.

When forming a high-quality dense coating layer, a two-stage blade finish, that is, a coating film 4 having a coating film thickness of about 200 μm by the blade 1 of the coating unit A in the preceding stage is used.
After forming the film, the required film thickness (6 to 30 g / m ² / equivalent to the solid amount on one side) by the finishing blade 1 ′ of the scraping section B in the subsequent stage.
I am trying to finish. 6 and 7 show a conventional double-sided simultaneous coating apparatus, FIG. 6 is a side view, and FIG. 7 is an enlarged side view of a portion indicated by an arrow X in FIG.

1 is a blade, 2 is a blade clamp device, 3 and 3 are slit type blowing heads, 4 is a coating liquid, 6 is a continuously running web, 7 is a pressure tube, 12 and 1
2 is an application roll that rotates in the direction of the arrow. In the double-sided simultaneous coating apparatus shown in FIGS. 6 and 7, the coating liquid 4 is blown out from each slit type blowing head 3 to coat the surface of each application roll 12 with the coating liquid (coating liquid that gives up starch liquid). After coating 4, the excess coating liquid 4 is scraped off by the surface of the tip of the blade 1 to form a coating layer having a uniform thickness on the surface of each application roll 12, and then the roll nip of each application roll 12 is formed. A web 6 that continuously runs through this coating layer when passing through a section.
I am trying to transfer it to both sides.

In this case, since the surface of the roll 12 is higher in smoothness than the web 6, usually, a blade longer than the blade 1 shown in FIG. 5 is used as the blade 1, and each application roll 12 and each blade 1 are used. By lowering the contact pressure with the tip portion, a coating film having a thickness of about 10 to 30 microns is formed.

[0007]

In the conventional coating device shown in FIG. 5, the coating liquid 4 is directly applied to the continuously running web 6 and then the excess coating liquid 4 is scraped off. A relatively thick coating area (6 to 30 s / m ² / solid on one side) produces a high quality product. The conventional coating apparatus shown in FIGS. After coating, when it passes through the roll nip portion, it is transferred to both surfaces of the web 6 that continuously runs.

In these coating apparatuses, the coating speed is 100
When the pressure is increased to about 0 m / min, the fluid pressure commensurate with that increases the tip portion (blade edge) of the blade 1, so that the pressure tube 7 is arranged behind the blade 1. But 1
It is not possible to prevent the tip portion (blade edge) of the blade 1 from being lifted up by only one pressurizing tube 7, and the tip portion (blade edge) of the blade 1 cannot be maintained in an ideal wedge state.

Therefore, in the coating apparatus shown in FIG. 5, when only the front blade 1 is used, long operation cannot be performed due to the breathing phenomenon a at the blade tip portion due to negative pressure, and the finish coating surface is smooth. Disappear. When the front blade 1 and the rear blade 1 ′ are used, the front blade 1 forms a coating film with a pressure of 200 μm, but the tip portion of the blade 1 is still formed by the coating speed of about 1000 m / min. The cutting edge) rises and waviness occurs in the direction orthogonal to the flow, and the density remains in the finishing quality of the latter stage, or the scraping mist on the finishing blade 1'becomes large and the surrounding work environment deteriorates. ,
Cleaning frequency increases.

In the coating apparatus shown in FIGS. 6 and 7, 1000
In the high-speed coating area around m / min, the pressure of the tube behind the tube increases as the fluid pressure increases. In this case as well, the tip portion (blade edge) of the blade 1 is placed in an ideal wedge state. It cannot be maintained, the tip of the blade 1 floats, and waviness occurs in the direction orthogonal to the flow, and this streak remains even after passing through the roll nip portion, and in severe cases, even after printing. Problems such as uneven printing gloss occur.

The breathing phenomenon a means that the blade 1 deviates from the ideal shape due to excessive loading tube pressure in the high speed range, the tip of the blade 1 floats up, and negative pressure causes mist. , A phenomenon in which the mist accumulates in a wet state on the back surface side of the tip portion of the blade 1. Further, the undulation phenomenon is a ring pattern of the same phenomenon that occurs in a roll coater having a curvature equal to that of the tip of the blade 1 when it floats. Aggravates the surrounding environment.

FIG. 8 shows a conventional example of a coating apparatus proposed to solve the above problems. With this coating device,
Two pressure tubes 7 are arranged on the back surface of the blade 1, and of these pressure tubes 7, the pressure tube 7 on the blade rear end side is used as a pressure tube for determining an ideal curvature of the blade 1, The pressure tube 7 on the blade tip side is used as a pressure tube for determining the surface pressure so as to cover a wide coating speed range and coating liquid specifications. When a profile defect occurs, it is necessary to replace the two pressure tubes 7, and
It is necessary to remove or clean the adhered matter fixed around the supply pipe, which causes a problem of troublesome maintenance.

The present invention has been proposed in view of the above problems, and an object of the present invention is to make it possible to scrape a coating film applied to a web up to a thick film and to improve final finish quality. An object of the present invention is to provide a coating apparatus that can be improved and can be easily maintained and managed.

[0014]

In order to achieve the above object, the present invention applies a coating liquid to a surface to be coated, and then scrapes off the excess coating liquid on the tip surface side of a blade. In a coating apparatus for forming a coating layer on a surface to be coated, a tapered taper portion is formed on the back surface of the tip of the blade to form a reverse taper blade (claim 1).

In the above coating apparatus, after applying the coating liquid to the web continuously running from the backing roll, the excess coating liquid is scraped off by the front surface side of the tip of the reverse taper blade to form a web. You may make it form a coating layer (Claim 2). In the coating device, the coating liquid is applied to a pair of applicator rolls, and then the excess coating liquid is scraped off by the tip surface side of the reverse taper blade and applied to the surface of each applicator roll. After forming the coating layer, the web may be passed through the nip portion of each applicator roll to form the coating layer on both surfaces of the web (claim 3).

In the coating apparatus, when the width of the reverse tapered blade is L and the thickness of the blade is t, the width of the tapered portion is 1 / 6L to 1 / 3L and the thickness of the blade tip portion is 1 It may be / 3t to 4 / 5t (claim 4). In the coating device, a clamp device that supports the reverse taper blade, a swingable slit-type blowing head that supports the clamp device, and a tip surface of the blade by swinging the slit-type blowing head. And a pressing means for pressing the side against the web (claim 5).

[0017]

The above-mentioned conventional coating device, that is, a coating device for directly coating the web with the coating liquid as shown in FIG. 5 (when finishing only in the former stage, applying in the former stage, and applying a required amount in the latter stage) A coating device that may scrape the liquid) or a coating device that applies the coating liquid onto the applicator roller and then transfers it to the web at the roller nip portion as shown in FIGS. 6 and 7. In order to obtain a coating amount of the required thickness, it is necessary to maximize the surface pressure at the blade tip (blade edge), but with these coating devices, the maximum surface pressure value is the blade tip → pressure. After moving to the tube position, the surface pressure at the tip of the blade is extremely reduced. However, in the coating apparatus of the present invention, a tapered taper portion is formed on the back surface side of the tip of the blade, and the tip surface side of this reverse taper blade firmly contacts the coating layer due to the flexibility of this portion. on the other hand,
The rigidity of the reverse taper blade rear surface side (see the hatched portion in FIG. 2B), especially the rigidity of the 1a ′ portion prevents the blade tip from rising, so that the coating film applied to the surface to be coated is coated. The film is scraped up to a thick film, at which time there is no waviness or waviness and the final finish quality is improved. Further, in the reverse tapered blade, the portion closer to the rear portion than the front end portion may be pushed toward the web by the pressing mechanism, and it is not necessary to use a plurality of pressing tubes, and maintenance is facilitated.

[0018]

EXAMPLES Next, a coating apparatus of the present invention will be described with reference to an example shown in FIGS. FIG. 1 is a side view of the coating apparatus,
2A and 2B are enlarged side views of the blade. In FIG. 1, A is a front coating section, and B is a rear scraping section.

The front coating section A is a blade clamp device 2 having a reverse taper blade 1 and a metal bar 7'arranged behind the blade 1 described later, and a slit type blower supporting the blade clamp device 2. And a head 3. 5 is a backing roll that rotates in the direction of the arrow, 6 is a web that runs continuously, and 9 is a slit-type blowing head 3
The rotation center of 10 is a jack (pressurizing means) 10 is fixed, 11
Is a stopper provided on the side surface (front and rear) of the slit type blowing head 3.

Further, the scraping section B in the latter stage comprises a finishing blade 1'and a van 8 for storing the coating liquid 4 scraped by the finishing blade 1 '. As shown in FIGS. 2A and 2B, the reverse-tapered blade 1 of the front coating section A has a tapered taper portion 1a on the back surface of the tip portion of the blade 1 as shown in FIGS.
To form a reverse tapered blade. When the width of the reverse tapered blade 1 is L and the thickness of the blade 1 is t, the width of the taper portion is 1 / 6L to 1 / 3L, and the thickness of the blade tip portion is 1 / 3t to 4 / 5t. ing.

Next, the operation of the coating apparatus shown in FIGS. 1 and 2 will be specifically described. After the coating liquid 4 is blown out from the slit type blowing head 3 and the coating liquid 4 is applied to the web 6 that continuously runs together with the backing roll 5, the excess coating liquid 4 is clamped in the coating part A in the preceding stage. The tip end surface side of the reverse taper blade 1 attached to the apparatus 2 is scraped off to form a coating layer on the web 6.

At this time, the stoppers 11 provided on the side surfaces (front and rear) of the slit type blowing head 3 are pressed against the fixed jack 10 and the jack 10 is operated in the expanding and contracting direction, so that the slit type blowing head 3 and the blade clamp device 2 are provided. And are swung in the direction of the web 6 about the center of rotation 9, and the tip side surface side of the inversely tapered blade 1 is pressed against the web 6,
The tip of the reverse tapered blade 1 is bent. X in FIG.
Indicates the bending amount of the tip portion of the inversely tapered blade 1.

The tip portion of the inversely tapered blade 1 bends as described above by receiving the reaction force of the metal bar 7'in the back, but when the bending amount x of the tip portion is small, only the corner portion on the surface side of the tip portion is bent. Only the web 6 is hit, but when the bending amount x of the tip end becomes larger than the order of several mm, the web 6 is hit on the surface. At this time, the surface side of the tip portion of the inversely tapered blade 1 firmly contacts the coating layer due to the flexibility of this portion, while the surplus portion on the back surface side of the blade (see the parallel hatched portion in FIG. 2B), especially Since the rigidity of the 1a 'portion prevents the tip portion of the inversely tapered blade 1 from being lifted up, the coating film applied to the web 6 is scraped up to a thick film thickness without waviness or waviness. Improve the final finishing quality. In addition, the tip portion of the reverse taper blade 1 is provided with a pressure mechanism 2, 3, 7 ′,
It suffices to push in the direction of the web 6 by means of 9, 10, 11 and a plurality of pressurizing tubes are not required, and maintenance can be easily performed.

FIG. 3 shows the stable areas of coating when using the conventional parallel blade and when using the inverse tapered blade of the present invention. When the conventional parallel blade is used, the tip starts to float near the coating speed of 1000 m / min, and at higher speeds, instability becomes remarkable, but the reverse tapered blade of the present invention is used. In that case, the stability is maintained even when the area reaches 1500 m / min.

This is shown in FIG. 4 as a relation between the coating amount (Note: not necessarily showing the final finishing amount) and the bending amount x or the tube pressure. The coating control area of the reverse taper blade 1 is mainly in the range from XX in FIG. 4 to the right, and the coating amount shifts to the right as the coating speed increases. Since the surface side of the tip portion firmly presses against the coating layer due to the flexibility of this portion, the coating film applied to the web 6 is scraped off until the film thickness becomes thick, and at that time, no waviness or waviness occurs. , Improve the final finishing quality.

This action is performed in the same manner regardless of whether the web is thick paper or the property of the coating liquid is changed. Even with a coating device that has a front coating section, after applying the coating liquid to the web,
The same applies to a coating device that transfers images when passing through the roll nip portion. Occasionally, the pressure mechanism 2, 3, 7 ', 9, 10, 11 of the reverse taper blade 1 may be replaced with one pressure tube.

[0027]

The coating apparatus of the present invention is constructed as described above and can achieve the following effects. The conventional coating device, that is, a coating device for directly coating the web with the coating liquid as shown in FIG. 5, or after applying the coating liquid on the applicator roller as shown in FIGS. 6 and 7. When using a coating device that transfers to the web at the roller nip, it is necessary to maximize the surface pressure at the tip (blade) of the blade when trying to obtain the coating amount of the target thickness. In the device, the maximum surface pressure value shifts from the tip of the blade to the pressure tube position,
The surface pressure at the tip of the blade is extremely reduced. However, in the coating apparatus of the present invention, a tapered taper portion is formed on the back surface of the tip portion of the blade, and the tip surface side of this reverse taper blade is firmly contacted with the coating layer by the flexibility of this portion. While being pressed, the rigidity of the reverse taper blade back surface side (see the hatched portion in FIG. 2 (b)), especially the rigidity of the 1a ′ portion, prevents the blade tip from rising, so it was applied to the surface to be coated. The coating film is scraped up to a thick film without causing ripples and waviness.
The final finishing quality can be improved. Further, the reverse taper blade only needs to push a portion closer to the rear portion than the front end portion toward the web by the pressing mechanism, and it is not necessary to use a plurality of pressing tubes, and maintenance can be easily performed.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of a coating apparatus of the present invention.

FIG. 2A is a side view showing a reverse taper blade of the coating apparatus, and FIG. 2B is an operation explanatory view of the reverse taper blade.

FIG. 3 is an explanatory diagram showing a stable area of coating when a conventional parallel blade is used and when a reverse taper blade of the present invention is used.

FIG. 4 is an explanatory diagram showing a relationship between a coating amount and a bending amount x or a tube pressure.

FIG. 5 is a side view showing an example of a conventional coating apparatus.

FIG. 6 is a side view showing another example of a conventional coating apparatus.

7 is an enlarged side view of an arrow X part in FIG.

FIG. 8 is a side view showing still another example of a conventional coating apparatus.

[Explanation of Codes] A coating section in front stage B scraping section in rear stage 1 reverse tapered blade 1a taper portion of reverse tapered blade 1 1'finishing blade 2 clamping device 3 slit type blowing head 4 coating liquid 5 backing roll 6 Web 7'Metal Bar 8 Van 9 Rotation Center of Slit-Type Blow Head 3 Jack (Pressure Means) 11 Stopper

Claims (5)

[Claims] 1. After coating the coating liquid on the surface to be coated, surplus coating liquid is scraped off by the front surface side of the blade,
A coating apparatus for forming a coating layer on a surface to be coated, wherein a tapered taper portion is formed on the back surface of the tip of the blade to form a reverse taper blade. 2. A coating solution is applied to a web that continuously travels from a backing roll, and then excess coating solution is scraped off by the surface of the tip of the inversely tapered blade to form a coating layer on the web. The coating apparatus according to claim 1, which is formed. 3. A coating solution is applied to a pair of applicator rolls, and then excess coating solution is scraped off by the tip end surface side of the reverse taper blade to apply the coating solution to the surface of each applicator roll. The coating apparatus according to claim 1, wherein after forming the layer, the web is passed through the nip portion of each applicator roll to form a coating layer on both surfaces of the web. 4. The width of the taper portion is ⅙L to where the width of the reverse tapered blade is L and the thickness of the blade is t.
1 / 3L, thickness of the blade tip is 1 / 3t to 4 / 5t
The coating apparatus according to claim 1, wherein 5. A blade clamp device for supporting the inversely tapered blade, a swingable slit type blowing head for supporting the clamp device, and a surface of a tip portion of the blade for swinging the slit type blowing head. 5. The coating apparatus according to claim 1, further comprising a pressing means for pressing the side against the web.