JPH0829281B2 - Paper coating method and equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for producing a coated paper produced by a blade coating method, and more specifically, coating a coated paper produced by the blade coating method. TECHNICAL FIELD The present invention relates to a coating method and apparatus with reduced unevenness.

(Prior art) Printing paper such as art paper, coated paper, lightweight coated paper, white board coated paper, and information industry paper such as pressure-sensitive paper and thermal paper are used to give gloss or to perform a predetermined function. One or both sides are coated with resin paint, pressure-sensitive recording paint, heat-sensitive recording paint, or the like.

The most common coating method for such coated paper is the blade coating method.

Hereinafter, a conventionally known blade coating method will be described with reference to FIG.

The conventional blade coating method uses a backing roll 1 and a paper 2
The paint is applied to the paper 2 by the paint supply device 3 such as a fountain, and the paint applied by the blade 4 is scraped off to adjust the applied thickness of the paint.

Since the backing roll 1 guides the paper 2, the paper powder 5 adheres to the surface of the backing roll 1,
If this is not removed, uneven coating of the paint may occur during the next coating.

Therefore, a cleaning doctor 6 is provided to collect the cleaning liquid 7 and remove the paper dust 5.

On the other hand, a paper coating device having a structure as shown in FIG. 4 is also known. That is, the paper 42 is guided by a roll 41 having a rubber surface, the paint is applied to the paper 42 by a paint supply device 43 including a roll coater, and the paper is applied by a blade 44. Adjust the coating thickness by scraping off the paint.

Since the roll 41 guides the paper 42, it is desirable that the paper 42 is in close contact with the roll 1. However,
In reality, a gap is created between the paper 42 and the surface of the roll 41,
42 slips, leaving uneven coating. Therefore, the surface of the roll 41 is wetted with water by the shower device 45 so that the paper 42 and the roll 41 are adhered to each other. Where the contact roll
46 is for contacting with the roll 41 and adjusting the coating thickness of water formed on the surface of the roll 41.

(Problems to be Solved by the Invention) However, although the paper dust 5 can be removed by washing with the cleaning doctor 6, the paint adhering to the backing roll 1 cannot be sufficiently removed. It was That is, since the paper 2 permeates the liquid, the liquid coating material permeates the paper 2 and adheres to the surface of the backing roll 1. Such permeation of the coating material occurs remarkably in the portion where the paper 2 is pressed by the blade 4, and latex is used as a binder of the coating material for low speed coating (50
0m / min), it appears remarkably. In this way, the paint adhered to the surface of the backing roll 1 becomes a paint residue together with the paper powder 5 and remains adhered on the surface of the backing roll 1, and it is difficult to remove the adhered components only by cleaning with the cleaning doctor 6. Was becoming.

Therefore, according to the conventional blade coating method, the coating residue on the surface of the backing roll 1 causes uneven coating on the paper 2, and the manufactured coated paper may be wrinkled to deteriorate the quality.

On the other hand, the known paper coating device shown in FIG. 4 is for improving the adhesiveness between the paper 42 and the roll 41, so that no consideration is given to the paper dust adhering to the surface of the roll 41. In addition, uneven coating caused by this coating device
Since it is the coating unevenness caused by the slip of the paper, it does not suggest the coating unevenness due to the adhesion of the paper powder.

Therefore, an object of the present invention is to eliminate the coating unevenness of paper and improve the quality of the coated paper produced by a simple method and apparatus.

(Means for Solving the Problems) A feature of the present invention is that a liquid such as water is previously attached to the backing roll surface so that the coating does not attach to the backing roll surface, and thus the liquid of the liquid is attached to the backing roll surface. It's about making a thin film.

When the backing roll is wetted with the liquid in advance to form a thin film of the liquid as described above, even if the paint penetrates the paper, it is prevented from adhering to the backing roll.

As a result, paint dust produced by mixing paper powder and paint is eliminated, and even if paint dust is present, the amount is small, so that the paint dust can be easily removed by a cleaning doctor and a cleaning liquid.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view for explaining a paper coating method and apparatus according to an embodiment of the present invention. In the blade coating method according to the present embodiment, the backing roll 11 guides the paper 12 and Paint is applied to the paper 12 by a paint supply device 13 such as a fountain provided below the backing roll 11. A blade 14 is provided in contact with the paper 12 in order to scrape off the applied coating material and adjust the coating thickness.
Also, at the position after guiding the paper 12,
16 is provided, whereby the cleaning liquid 17 is accumulated and the paper dust 15 and the like are removed.

Although the above is the same as the conventionally known blade coating method, in the present invention, the following liquid coating step including a squeeze coater is provided between the cleaning doctor 16 and the coating material supply device 13.

The squeeze coater according to this embodiment includes a pan 19 in which a liquid 18 such as water is stored, a pickup roll 20 partially immersed in the liquid 18 of the pan 19, and an applicator roll 21 rotating in contact with the pickup roll 20. The metering roll 22 is in contact with the applicator roll 21 and rotates, and the metering roll 22 is in contact with the backing roll 11. The meaning that the rolls come into contact with each other and rotate does not necessarily mean that the rolls are actually in contact with each other, and it does not matter what the intervals are as long as a predetermined amount of liquid is transferred from one roll to the other roll. There is no such thing.

The present invention relates to the pickup roll of the squeeze coater.
The liquid 18 in the pan 19 is scraped up by 20 and passed to the applicator roll 21 and further to the metering roll 22, after which the liquid is attached to the surface of the backing roll 11.

Although the rotation direction of each roll in the squeeze coater can be freely selected, it is desirable to select the rotation direction of the contact points of each roll to be the same direction as illustrated.

Further, as the pickup roll 20, a chrome-plated mirror roll may be adopted, but it is desirable to use a chrome-plated mesh roll in order to effectively scrape up the liquid.

Furthermore, it is desirable that the applicator roll 21 and the metering roll 22 be rubber rolls, and if the material has durability against the liquid used (water-resistant material such as silicone rubber, urethane rubber, etc.), it is particularly preferable. No material is selected.

 The specifications of one embodiment of the present invention are shown below.

In the under-base coating process of thermal recording paper, the roll peripheral speed ratio is 1 backing roll, 1 metering roll, 0.8 applicator roll, and pickup roll.
0.7 and 500m / m with nip pressure between each roll of 2kg / cm ^2.
The coating speed was in. The coating amount of water is 5
-10% is desirable, and within this range, no wrinkles were generated and no paint residue was left on the cleaning doctor.

The squeeze coater according to the present invention is not limited to the above embodiments.

 For example, a coating means as shown in FIG. 2 may be used.

Referring to FIG. 2, the first roll 31 and the first roll 31
A second roll 32 in contact with the third roll 32 in contact with the second roll 32
The roll 33 is provided, and the third roll 33 is a backing roll.
Installed in contact with 35. And the first roll 31 and the second roll
A liquid supply device 34 for supplying a liquid is provided between the liquid supply device 34 and the liquid supply device 32.
The meaning that the rolls come into contact with each other and rotate does not necessarily mean that the rolls are actually in contact with each other, and it does not matter what the intervals are as long as a predetermined amount of liquid is transferred from one roll to the other roll. There is no such thing.

The other structure is similar to that of FIG.

Also in the embodiment shown in FIG. 2, it is possible to form a liquid thin film on the surface of the backing roll 35.

Also, in the embodiment of FIG. 2, the first roll 31 is omitted,
A liquid supply device 34 'is provided between the second roll 32 and the third roll 33.
It is also possible to adopt a configuration in which

Furthermore, as the liquid supply apparatus applied to the present invention, a liquid supply apparatus having the following configuration can be adopted. That is, a liquid supply device having a structure capable of transferring a thin film liquid onto a backing roll, such as a paint supply device for applying a paint by providing a desired gap between the backing roll and the backing roll, is the present invention. Applicable.

Although water is desirable as the liquid that leaks the backing roll, the liquid of the present invention is not limited to water, and any liquid that does not attack the paper and the backing roll, such as alcohol, can be used.

(Effects of the Invention) According to the present invention described above, the following effects are achieved.

Since the amount of paint adhered to the backing roll is reduced, clogging of paint debris in the cleaning doctor is eliminated, uneven coating on paper is eliminated, and quality can be improved. Moreover, even if paint dust is generated, it is small in amount, and therefore can be easily removed by a cleaning doctor and a cleaning liquid.

Furthermore, since the structure is simple and can be easily added to the conventional device, there is an advantage that the conventional device can be used as it is.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention, FIG. 2 is a schematic view showing another embodiment of the present invention, FIG. 3 is a schematic view showing a conventionally known blade coating method, and FIG. It is a schematic diagram showing a conventionally well-known liquid application device. (Description of symbols) 11: backing roll, 12: paper, 13: paint supply device, 14: blade 15: paper dust, 16: cleaning doctor, 17: cleaning liquid, 18: liquid 19: pan, 20: pickup roll, 21 : Applicator roll 22: Metering roll, 31: First roll, 32: Second roll 33: Third roll, 34: Liquid supply device, 35: Backing roll

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area // B41M 5/124 5/26

Claims (3)

[Claims] 1. A coating method in which a paint supply device is provided in contact with a paper guided by a backing roll, and the paint is applied to the paper by the paint supply device, wherein a liquid is applied to the backing roll before guiding the paper. A method for coating paper, characterized in that a liquid is applied by an application device, and the cleaning liquid is accumulated on a backing roll after guiding the paper by a cleaning doctor to remove paper dust. 2. A coating apparatus in which a paint supply device is provided in contact with a paper guided by a backing roll, and the paint is applied to the paper by the paint supply device, wherein the backing roll before guiding the paper is liquid. A liquid coating device for coating paper, and further a cleaning doctor is provided on the backing roll after guiding the paper, and a pool of cleaning liquid for removing paper dust is formed by the cleaning doctor. apparatus. 3. A liquid applying device, a pan in which the liquid is stored, a pickup roll immersed in the liquid in the pan, an applicator roll rotating in contact with the pick-up roll, and a contact with the applicator roll. 3. The paper coating apparatus according to claim 2, wherein the paper coating apparatus comprises a squeeze coater composed of a rotating metalling roll.