JPH06114310A - Coating method and apparatus therefor - Google Patents

Abstract

PURPOSE:To directly remove a paint and prevent the paint from adhering even if painting is carried out at high speed by installing a paint removing means near enough to a coating means to enable the removing means to touch the paint to be removed. CONSTITUTION:A base film 31A which is not yet coated is conveyed by a guide roller 19, pinched between a backup roll 16 and a gravure roll 15 and conveyed, and coated with a magnetic paint 28. Against the base film 31B coated with a magnetic paint 28, a rotary disk 1 of which outer circumferential part is brought into contact with the uncoated part of the base film and which rotates is installed in the down stream side of the rolls 15, 16. Since the outer circumferential end of the rotary disk 1 is so installed as to be brought into contact with a meniscus film, the magnetic paint 28 on the meniscus film adheres to the main face of the rotary disk 1 and is evacuated toward the rotating direction. Consequently, the magnetic paint 28 on the meniscus film is made not to adhere to the uncoated part of the base film 31B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating method and an apparatus therefor, for example, a coating method for coating a magnetic coating on a base film in the manufacture of a magnetic recording medium and a coating apparatus used for this method.

[0002]

2. Description of the Related Art A magnetic recording medium such as a magnetic tape or a floppy disk is manufactured by a process in which a magnetic coating is applied to a wide long base film by gravure coating, dried, and then cut into a predetermined width.

The magnetic paint is supplied by a gravure roll and is applied to the surface of a base film which is conveyed by being sandwiched between a gravure roll and a backup roll. The base film coated with the magnetic paint needs to be discharged from a coating part including a gravure roll and a backup roll, and the magnetic paint needs to be applied to the surface of the base film in a substantially uniform thickness.

Usually, the magnetic paint is applied to a region sandwiched by a small amount of both side edges of the base film.

[0005]

From the viewpoint of productivity, it is desired to increase the transport speed (coating speed) of the base film.

However, when the coating speed increases, the magnetic paint (hereinafter sometimes referred to as paint) scatters at the separating portion where the base film separates from the gravure roll.
On the upstream side of the gravure roll, which is in contact with the part facing the backup roll (application position), the paint roll is pressed by the backup roll to form a paint puddle. A film called a Minescus film is generated on the downstream side of the coating position around the portion.

When this minescus film is separated from the base film, paint scattering occurs, and the scattered droplets of the magnetic coating adhere to the surface of the magnetic layer which is applied almost uniformly, which is the main cause of dropout. Becomes For this reason, the coating speed is set to about 200 to 250 m / min, and cannot be further increased.

[0008]

As a coating apparatus for solving the above problems, FIG. 9 (shown as a reference example) is a front view and FIG.
A coating apparatus having the structure shown in FIG. 10 which is a cross-sectional view taken along the X-ray is conceivable.

In this apparatus, the magnetic paint 28 supplied from the magnetic paint supply unit 17 is carried on the surface of the gravure roll 15, the layer thickness is regulated by the doctor blade 18, and the magnetic paint 28 is sandwiched between the gravure roll 15 and the backup roll 16. It is applied to the surface (lower surface in the figure) of the uncoated base film 31A that is conveyed while being conveyed. The base film is fed from the gravure roll 15 and the backup roll 16 and becomes the coated base film 31B.

Gravure roll 15 and backup roll 16
A fixing plate 42 is arranged on the downstream side of the base film 31B, which is slightly apart from the coated base film 31B, and the fixing plate 42 is disposed below the fixing base plate 31B. By 42, the adhesion to the applied base film 31B is prevented.

In this device, the above problem can be solved to a considerable extent, but since the fixing plate 42 is separated from the base film 31B on which the coating is applied, the droplets 33a of the paint on the base film 31B on which the coating has been applied are removed. Adhesion is not completely prevented and is not perfect. Therefore, the base film transport speed is set to 250 to 300 m / min. Moreover,
In continuous coating, the fixing plate 42 is gradually soiled by the adhered paint droplets, and it is necessary to periodically interrupt the coating operation for cleaning, which is a problem in terms of productivity.

[0012]

The present invention has been made in view of the above circumstances, and is an undesired coating on an object to be coated (for example, the base film 31B described above) even at a high coating speed. It is an object of the present invention to provide a coating method and a coating device in which the adhesion of (for example, the above-mentioned paint droplets 33a) is reliably prevented and which has high reliability and high productivity. In order to achieve this object, the following structure is provided. I am trying.

A first aspect of the present invention relates to a coating method for removing the coating material adhering to the non-coated surface of the coating object when the coating material is coated on the coating object.

The second invention has a coating means and a coating material removing means for removing the coating material adhering to the non-coated surface of the object to be coated, and the coating material removing means contacts the coating material to be removed. Thus, the present invention relates to a coating device arranged near the coating means.

In the above first and second inventions, it is preferable to do the following respectively. (i) The paint removing means is a disk-shaped paint removing means that is rotationally driven; (ii) supplying a paint solvent to the paint removed by the paint removing means; (iii) the removed paint. Scraping from.

[0016]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 is a front view of an essential part of a coating device for applying a magnetic paint to a base film, and FIG. 2 is a right side view of the essential part of the device shown in FIG.

The uncoated base film 31A is conveyed while being guided by the guide roller 19, comes into contact with the backup roll 16, is sandwiched between the backup roll 16 and the gravure roll 15 and is conveyed, and the magnetic paint is applied between both rolls. Is applied. Pre-coated base film 31B away from both rolls
Is guided by the guide roller 20 and conveyed to a drying section described later, and is wound after drying.

The magnetic paint 28 is supplied from the magnetic paint supply unit 17, is carried on the surface of the gravure roll 15, and the layer thickness is regulated by the doctor blade 18, and the surface of the uncoated base film 31A (lower side in the figure). Surface).

The gravure roll 15 is provided with a shaft portion 15a which is supported by a bearing (not shown) and is rotatable. The backup roll 16 has a backup section 16a.
A small diameter portion 16b having a slightly smaller diameter is provided on both sides of the shaft, and a shaft portion 16c which is rotatably supported by a bearing (not shown) is provided on both sides thereof so as to be rotatable.

Backup unit 16 of backup roll 16
The length a is smaller than the area of the gravure roll 15 excluding the shaft portion 15a, and both side edge portions of the coated base film 31B have backup portions 16 of the backup roll 16
It protrudes from a, and both side edge portions become non-applied portions 31Ba to which the magnetic paint is not applied.

Gravure roll 15 and backup roll 16
Pre-applied base film 31 with magnetic paint applied between
Immediately downstream of both rolls 15 and 16 with respect to B, a rotary disc 1 is provided, the outer peripheral portion of which is in contact with the non-coated portion 31Ba of the base film and rotates. The material of the rotary disc 1 is stainless steel or carbon tool steel, but it may be plastic having a certain degree of rigidity.

The rotary disc 1 is inclined with respect to the conveying direction of the coated base film 31B as shown in FIG. 1 and intersects with the conveying direction of the base film 31B as shown in FIG. It is inclined with respect to the vertical direction (this inclination is not shown in FIG. 1) so that the outer peripheral edge portion of the rotary disk 1 contacts the non-application portion 31Ba. Therefore, as shown in FIG. 2, the non-application portion 31Ba is bent toward the small diameter portion 16b of the backup roll by the rotary disk 1 at this contact position.

The center of the rotary disc 1 is attached to the shaft of the driven side chain sprocket 2, and the driven side chain sprocket 2, the driving side chain sprocket 3 and the chain 4 hung on both chain sprockets 2 and 3.
Are housed in a hollow cantilever 5. The rotary disc 1 is rotated via the chain 4 and the driven chain sprocket 2 by the rotation of the drive side chain sprocket 3 attached to the shaft thereof by driving the motor 6.

When the base film is conveyed at a high speed, a paint pool 32 is formed immediately upstream of the contact position between the gravure roll 15 and the uncoated base film 31A. The paint wraps around from both ends of the base film, and a minescus film 33 is formed on both sides immediately downstream of the contact position.

As shown in FIG. 1, the rotary disc 1
Is disposed so that its outer peripheral edge contacts the minescus film 33, so that the magnetic paint of the minescus film 33 adheres to the main surfaces (front surface and back surface) of the rotary disk 1 and retreats in the rotation direction. Become. Therefore, the magnetic paint of the minescus film 33 is prevented from adhering to the non-coated portion 31Ba of the base film. Of course, undesired magnetic paint droplets do not adhere to the coated surface of the coated base film 31B.

Moreover, as shown in FIG. 2, the outer peripheral edge portion of the rotary disk 1 contacts the non-coated portion 31Ba of the base film and bends it toward the small diameter portion 16b of the backup roll. Adhesion of the magnetic paint to the non-coating portion 31Ba is further reliably prevented. The reason is that the non-application portion 31 of the rotary disc 1
This is because the contact with Ba is reliable and the rotary disc 1 can be brought closer to the coating position.

The magnetic paint adhered to the main surface of the rotary disk 1 is scraped off by a pair of doctor blades as shown in FIGS. The rotary disk 1 is rotatably attached to the tip of the cantilever 5. A pair of brackets 12A and 12B are fixed above and below the cantilever 5, and doctor blades 11A and 11B attached to the brackets 12A and 12B come into contact with the main surface of the rotary disc 1.

FIG. 4 is a plan view showing the positional relationship between the cantilever, the rotary disk and the doctor blade, and FIG. 5 is a partially enlarged view of FIG. 1 showing the mechanism of the shaft support of the rotary disk 1 by the driven side chain sprocket 2. .

Thus, the magnetic paint adhered to the rotary disk 1 is scraped off by the doctor blades 11A and 11B. In this way, the rotary disk 1 is always kept in a clean state, and the effect of preventing the magnetic paint from adhering to the base film does not deteriorate. Moreover, there is no need to interrupt the coating operation to clean the rotary disk, which also improves productivity.

The magnetic paint attached to the rotary disk is
It is recommended to dissolve with a solvent that dissolves the binder component of the magnetic paint, and then scrape with a doctor blade. In this example, as shown in FIG. 6 which is a cross-sectional view taken along the line VI-VI of FIG. 4, the doctor blade in the rotating direction of the rotary disk 1 is shown.
Nozzles 13 and 13 for solvent drip are arranged on the upstream side of 11A and 11B. The solvent supplied from the nozzles 13 and 13 dissolves the binder component of the magnetic paint adhered to the rotary disk,
The magnetic paint becomes a low viscosity liquid and doctor blade 11A,
Easily scraped by 11B.

FIG. 7 is a perspective view showing a rotary disk, a doctor blade, a cantilever supporting them, and their surroundings.

A cantilever 5 is fixed to a bracket 8 which is fixed to a column 9 which supports a gravure roll 15.

Flexible tubes 14 and 14 are connected to the nozzles 13 and 13 to supply a solvent. The nozzles 13, 13 and the tubes 14, 14 are supported by the cantilever beam 5 or the brackets 12A, 12B, but the supporting means is not shown.

FIG. 8 is a schematic front view of the entire apparatus including a coating apparatus in which a magnetic layer is formed on an uncoated base film to form a wide and long magnetic sheet.

The uncoated base film 31A wound around the hub 22 is guided by the guide rollers 21, 21, 21 while being conveyed with a proper tension applied thereto, and passes through the guide roller 19 and the backup roll 16 The magnetic paint is applied by being sandwiched between the backup roll 16 and the gravure roll 15.

Base film 31B coated with magnetic paint
Through the guide rollers 20 and 23, the magnetic paint is dried by the hot air through the drying section 24 to become the magnetic sheet 31C, and the magnetic layer is flattened through the calendar section 25 including a large number of rolls 26, and the hub is formed. It is wound around 27. The magnetic sheet 31C wound around the hub 27 is cut into a predetermined width in the next step and wound again to form a pancake.

As described above, in this example, undesired magnetic paint droplets are prevented from adhering to the non-applied portions on both side edges of the base film or the already-applied magnetic paint layer, thus preventing the occurrence of dropout. In addition, the magnetic sheet coated with the magnetic paint and dried has a uniform thickness and can be wound smoothly.

The main specifications of the coating apparatus in this example are as follows. Rotary disk dimensions Diameter 150 mm, thickness 1.0 mm, peripheral edge sino angle 30 degrees Rotary disk rotation speed 20 to 100 rpm changeable Air engine with spur gear drive (for use of flammable solvent) 80 to 400 rpm changeable rotary disk Contact angle: 6 degrees in both directions

When this apparatus was used to apply a magnetic paint under the conditions of a rotary disk rotation speed of 30 rpm, an organic solvent supply amount of 10 l / min, and a base film conveying speed of 400 m / min, no undesired magnetic paint adhesion was observed. A magnetic sheet was obtained. The above-mentioned transfer speed is 1.6 to 2.0 times that of the conventional one, and productivity is remarkably improved. The transport speed of 400 m / min is the upper limit of the capacity of the equipment used,
It is considered that the coating can be carried out even at a higher speed than this.

Although the embodiments of the present invention have been described above, various modifications can be made to the above embodiments based on the technical idea of the present invention.

For example, an endless belt that revolves can be used in place of the rotary disc. Further, the rotary disc or the endless belt may be brought into contact with the base film while being inclined only with respect to the base film transport direction. Further, the present invention can be applied not only to the coating of the magnetic paint on the base film, but also to other various coatings.

[0043]

According to the method of the present invention, the paint adhered to the non-coated surface of the object to be coated is removed. In the apparatus of the present invention, the paint removing means for the above removal is used. Since it is arranged in the vicinity of the coating means so as to come into contact with the coating material to be coated, the coating material can be removed directly and the coating material can be prevented from adhering to the non-coated surface even when coating is performed at high speed. As a result, the manufactured or semi-finished product after application has high quality and reliability, and is applied with high productivity.

[Brief description of drawings]

FIG. 1 is a front view of a main part of a coating device according to an embodiment.

FIG. 2 is a right side view of a main part of the coating apparatus of FIG.

FIG. 3 is a front view of relevant parts showing the relationship between the rotary disc and the doctor blade of the embodiment.

FIG. 4 is a plan view showing a positional relationship between the cantilever, the rotary disc, and the doctor blade.

5 is a partially enlarged view of FIG. 1 showing a mechanism of a rotary disc shaft support by a driven side chain sprocket.

6 is a cross-sectional view of a main part taken along line VI-VI in FIG.

FIG. 7 is a perspective view showing a rotary disc, a doctor blade, a cantilever supporting these components, and their surroundings according to an embodiment.

FIG. 8 is a schematic front view of a magnetic sheet manufacturing apparatus including the coating apparatus.

FIG. 9 is a front view of a coating apparatus of a reference example.

10 is a cross-sectional view taken along line XX of FIG. 9.

[Explanation of symbols]

 1 rotary disk 2 driven side chain sprocket 3 drive side chain sprocket 4 chain 6 motor (air engine) 11A, 11B doctor blade 13 solvent supply nozzle 14 solvent supply pipe 15 gravure roll 16 backup roll 16a backup part 16b small diameter part 17 magnetic paint supply Part 28 Magnetic paint 31A Uncoated base film 31B Applied base film 31Ba Non-coated part 32 Paint reservoir 33 Minescus film

Claims (5)

[Claims] 1. A coating method for removing a paint adhering to a non-coated surface of the coating object when the coating material is coated on the coating object. 2. A coating means and a coating material removing means for removing coating material adhering to a non-coated surface of an object to be coated, the coating material removing means contacting the coating material to be removed. A coating device disposed near the coating means. 3. The coating method or apparatus according to claim 1, wherein the coating material to be removed is removed by a disk-shaped coating material removing means, and the disk-shaped coating material removing means is rotationally driven. 4. The coating method or apparatus according to claim 1, wherein a paint solvent is supplied to the paint removed by the paint removing means. 5. The coating method or apparatus according to claim 1, further comprising a paint scraping unit that scrapes the paint removed by the paint removing unit.