JPH07116581A - Coating device - Google Patents

Abstract

PURPOSE:To sharply reduce the defective parts and to remarkably lower production cost by giving a liquid receiving plate a role in receiving a liquid film of the 1st position and causing it to flow in a liquid recovery vessel and moving a curtain liquid film forming part to the 2nd position without interference arising. CONSTITUTION:In a standby state just starting coating, the lower end of an edge guide 4 of a curtain liquid film forming part 10 is placed on a liquid receiving plate 7 and a liquid film in the shape of a curtain flows on the liquid receiving plate 7 and is recovered in a pan 6 of a liquid receiving vessel. On starting coating, the liquid receiving plate 7 is retreated and the curtain liquid film forming part 10 advances by D to the left and a gap approaches the holding surface of a supporting body 1 as shown by S. The curtain liquid film is turned into a coating film 24C, which is applied on the supporting body 1. Therefore, stationary coating begins. In this state, the vena contracta generated between the lower end part of the edge guide 4, the supporting body 1 is much smaller than ever, and a thick coating part of the edge part is about 1.2 times as thick as the stationary coating film, which will cause almost no trouble from a practical point of view.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention applies a silver halide photographic emulsion, an undercoating liquid, a magnetic layer coating agent and other various laminating agents to a continuously running strip-shaped support (hereinafter sometimes referred to as a web). The present invention relates to a coating device, particularly a curtain coating type coating device.

[0002]

2. Description of the Related Art Improvements have been made to curtain coating type coating devices, such as those disclosed in Japanese Patent Laid-Open No. 3-94863.

That is, as shown in the side view of FIG.
The coating liquid 24A flow-cast from the edge guide 4 is held at the end thereof to form a curtain-shaped liquid film 24B, which falls and is received by the liquid receiving plate 7 before the steady coating is started to store the liquid. The curtain-shaped liquid film 24B is caused to flow into the pan 6 of the container as the waste liquid 24D, and when the coating is started, the liquid receiving plate 7 slides in the inclined direction and moves backward as shown in the side view of FIG.
Is switched from flowing on the liquid receiving plate 7, and coating is performed as a coating film 24C on the support (web) 1 which is transported at a constant speed by the transport guide back roller 5.

At this time, as shown in the front view of FIG. 7, since the gap L between the edge guide 4 and the support 1 is quite large, a contraction flow 21B of the liquid film occurs at the end. Then, the curtain-shaped liquid film 24B is applied onto the support 1 to form the applied film 24C, but a considerably wide and thick applied portion 22B is formed at both edge portions in the width direction.

The gap L cannot be reduced to a certain extent or more because the liquid receiving plate 7 must be moved to move it in and out as described above. That is, it is practically impossible to make it less than 5 mm.

In order to avoid this, as shown in the side view of FIG. 6, an attempt has been made to lower the edge guide 4 in the vertical direction to reduce the gap L, but a gap is generated between the coater head 2 and the edge guide 4. The coating film enters into the gap due to the effect of surface tension, which causes a stripe-shaped unevenness in the curtain-shaped liquid film 24B, resulting in coating unevenness.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above drawbacks and prevents the coating film from being disturbed, and the thickness of the thick coating portions at both edges of the coating film is reduced to such an extent that it does not hinder practical use. It is an object to provide a coating device.

[0008]

This object is achieved by any of the following technical means a, b, c and d.

(A) In a coating apparatus using the curtain coating method, a curtain liquid film forming section in which an edge guide and a coater head for supporting both ends of the liquid film in a free fall section of the liquid film are integrated, and a coating target A back roll that guides and conveys the support, and a liquid receiving plate that is above the back roll surface and below the lower end of the edge guide are provided, and the curtain liquid film forming unit is located at a first position away from the support. And a second position adjacent to the curtain liquid film forming part. The liquid receiving plate receives the liquid film at the first position and causes the liquid film to flow into the liquid recovery container. Is movable so as not to cause interference when moving to the second position.

(B) The coating apparatus according to item (a), wherein the movement between the first position and the second position is performed in the horizontal direction.

(C) The coating apparatus according to item a, wherein the inclination angle of the liquid receiving plate at the first position is 10 to 80 °.

(D) The interference of the liquid receiving plate can be avoided by moving the liquid receiving plate in parallel with the inclination angle of the liquid receiving plate. Coating device.

[0013]

Embodiments of the present invention will be described with reference to the side views of FIGS. 1 and 2 and the front views of FIGS.

The edge guides 4 on both edges are integrally welded to the joint bracket 11 and integrated, and the fastening portion 11B of the bracket 11 is fastened and fixed to the mounting screw hole of the coater head 2 with a screw 11A.

The mounting screw holes provided in the coater head 2 are prepared according to the distance between the two edge guides 4 which varies depending on the coating width, and can be selected according to the required width.

In this way, the coater head 2 and the edge guide 4 are integrally connected to form the curtain liquid film forming portion 10, and the contact portion between the coater lip 2a of the coater head 2 and the edge guide 4 is not always moved. Since it is kept in the same state, the curtain-shaped liquid film 24B formed normally
Is always kept stable in the same state.

In this way, the curtain liquid film forming unit 10 in the preparatory state immediately before the start of coating, as shown in FIG. 1, causes the coating liquid 24A to flow over the coater head 2 and the curtain-shaped liquid from the coater lip 2a to both edge guides 4. Form film 24B. Then, the lower tip of the edge guide is located on the liquid receiving plate 7, and the curtain-shaped liquid film 24B is recovered in the pan 6 which is the flow liquid recovery container by using the liquid receiving plate 7 as the waste liquid 24D.

In this state, the distance L between the lower end of the edge guide 4 and the transport surface of the support 1 is set to a sufficient distance so that the liquid receiving plate 7 can slide and move in the tilt direction. Has become. The inclination angle of the liquid receiving plate may be set to an angle in a range where the curtain-shaped liquid film 24B does not overflow and spill, 10 to 80 ° is applicable, and preferably 30 to 60 °. Is appropriate.

At the start of coating, as shown in FIG. 2, the liquid receiving plate 7 moves backward, and the curtain liquid film forming portion 10 moves forward by a distance D to the left in the drawing, and the curtain liquid film forming portion 10 moves to the holding surface of the support 1 by the distance D. The gaps are close to each other as shown by S, and the curtain-shaped liquid film 24B is a coating film.
It becomes 24C and is applied onto the support 1 to start steady-state application.

In this state, as shown in the front view of FIG. 8, the contracted flow 21A occurring between the lower end of the edge guide 4 and the support 1 is smaller than the contracted flow 21B of the conventional example shown in FIG. It can be made much smaller, and the thickness of the thick coating portion 22A at the edge portion is about 1.2 times the steady coating film thickness C, and the thickness of the conventional thick coating portion 22A as shown in FIG. 7 is steady. It was much lower than the state where the coating film thickness C was about 2.8 times, and it was possible to make the change in the thickness almost practically acceptable.

In this example and the conventional example, the coating solution at this time is a silver halide photosensitive material for color paper,
Seven layers of it were simultaneously coated at a coating speed of 200 m / min, the coating flow rate was 2.5 cc / cm · s for the seven layers in total, and the viscosity was
It was 50 cp. In this embodiment, the clearance dimension S between the support 1 and the tip of the edge guide 4 was 0.3 mm.
In the conventional example, the gap dimension L was 5 mm.

In the present invention, not only the coating speed of 200 m / min but also 60 to 300 m / min is possible, and the coating flow rate is 2.5 cc / c.
It was confirmed that not only m · s but also 0.5 to 5.0 cc / cm · s was possible, and it was also possible to apply the viscosity of the coating liquid to 1 to 200 cp without any problem.

The state of contact between the coater lip 2a and the edge guide 4 is always fixed, and the state of formation of the curtain-shaped liquid film 24B can be always stabilized during coating.

While the liquid receiving plate 7 is retracted to switch to the regular coating, the curtain-shaped liquid film 24B hangs in an irregular state on the support 1 to cause defective coating at the front of the support. In order to make the section in this state as small as possible, the retracting speed of the liquid receiving plate 7 and the moving amount D of the curtain liquid film forming unit 10 from the first position to the second position are instantaneously high speed so as to be as short as possible. It is desirable to process. However, it is appropriate that the moving speed is 100 cm / s or less.

[0025]

EFFECTS OF THE INVENTION The curtain coating type coating apparatus of the present invention eliminates the phenomenon that the coating film becomes abnormally thick at the edge portion, enables uniform coating, and significantly improves the coating yield. It was

That is, in the past, the central portion was cut into a product to make it into a product, and the portion near the edge portion was cut into a defective product. However, the present invention greatly reduces the defective portion, and a large improvement in yield is achieved. The cost has been reduced significantly.

Further, the removal of the thick film at the edge portion can not only improve the yield but also prevent the roll contamination in the process due to the generation of the undried portion due to the film thickness, and reduce the time for cleaning the process. was there.

[Brief description of drawings]

FIG. 1 is a side view showing a state before starting coating according to an embodiment of the present invention.

FIG. 2 is a side view showing a state immediately after the start of coating according to an embodiment of the present invention.

FIG. 3 is a front view of an example of a curtain liquid film forming unit.

FIG. 4 is a side view of a conventional coating apparatus before coating is started.

FIG. 5 is a side view showing a state of the conventional coating apparatus immediately after the start of coating.

FIG. 6 is a side view showing the state of another conventional coating apparatus immediately after the start of coating.

FIG. 7 is a front view showing curtain liquid film coating by a conventional coating device.

FIG. 8 is a front view showing curtain liquid film coating by the coating apparatus of the present invention.

[Explanation of symbols]

 1 Support 2 Coater Head 2a Coater Lip 4 Edge Guide 5 Back Roller (Conveyance Guide Roller) 6 Pan (Liquid Storage Container) 7 Liquid Receiving Plate 10 Curtain Liquid Film Forming Section 11 Coupling Bracket 11B Fastening Section 21A, 21B Reduced Flow 22A, 22B Thick coating part (thick film part) 24A Coating liquid 24B Curtain liquid film 24C Coating film 24D Waste liquid 27 Contact part C Coating film thickness L, S Gap D Curtain liquid film forming part Moving amount

Claims (4)

[Claims] 1. A curtain liquid film forming section in which an edge guide and a coater head for supporting both widthwise ends of the liquid film in a free fall section of the liquid film are integrated in a coating device using a curtain coating method, and a coating target support. A back roll that guides and conveys the body and a liquid receiving plate that is above the back roll surface and below the lower end of the edge guide are provided, and the curtain liquid film forming unit is located at a first position away from the support. The liquid receiving plate is configured to be movable between the second position and the adjacent second position, and the liquid receiving plate serves to receive the liquid film at the first position and cause the liquid film to flow into the liquid recovery container. Second
The coating device is characterized in that it is movable so as not to cause interference when moving to the position. 2. The coating apparatus according to claim 1, wherein the movement between the first position and the second position is performed in a horizontal direction. 3. The coating apparatus according to claim 1, wherein an inclination angle of the liquid receiving plate at the first position is 10 to 80 °. 4. The interference of the liquid receiving plate can be avoided by moving the liquid receiving plate in parallel with the inclination angle of the liquid receiving plate. Coating equipment.