JP3006016B2 - Coating equipment for manufacturing magnetic recording media - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a coating apparatus for producing a magnetic recording medium for applying a magnetic paint or a back coat paint to a non-magnetic support, and more particularly to a gravure. This is related to the improvement of the roll.

[Summary of the Invention]

The present invention provides a coating apparatus for manufacturing a magnetic recording medium in which a non-magnetic support is applied with a magnetic paint or a back coat paint by a gravure roll. By cutting grooves continuous in a parallel direction, the coating is smoothed and high-speed coating is enabled.

[Conventional technology]

In general, audio tapes and video tapes are made by applying a magnetic paint made by dispersing and kneading a ferromagnetic powder, a binder, a dispersant, a lubricant, etc. in an organic solvent on a non-magnetic support such as a polyester film. A layer is formed. Further, in order to prevent the winding of the magnetic tape from being disturbed and to improve the surface property, running property, durability and the like, the non-magnetic support is formed by applying a back coat paint on the side where the magnetic layer is not provided. It is widely used to provide a back coat layer.

By the way, in applying these magnetic paints and backcoat paints on a non-magnetic support, a gravure method is often used from the viewpoint of paint thickness accuracy, application speed and the like.

The gravure method uses a coating device including a gravure roll having a spiral cell pattern engraved on the surface thereof and a backup roll for pressing the nonmagnetic support onto the gravure roll, and a liquid on the nonmagnetic support is used. This is a method of transferring paint. That is, in order to transfer the paint onto the non-magnetic support using this apparatus, the non-magnetic support is pressed against the gravure roll with a backup roll made of an elastic body, and the rolls are rotated so that the adjacent cell walls are rotated. This is a method in which the paint filled in each hollow (cell) is transferred onto a non-magnetic support.

[Problems to be solved by the invention]

When the paint is transferred by the gravure roll, a portion where the paint is not applied occurs on the non-magnetic support. This is because a pattern inverted from the cell pattern provided on the gravure roll is transferred to the non-magnetic support, and the paint is not filled at the top of the cell wall in contact with the non-magnetic support. As described above, when there is a portion where the paint is not applied, a lump of the paint called a bead or a splash is scattered, and this may adhere to the non-magnetic support to cause deterioration in quality. Therefore, in order to prevent these occurrences, the coating speed must be reduced, and it is difficult to significantly improve the productivity.

[Problems to be solved by the invention]

Therefore, the present invention has been proposed in view of such conventional circumstances, and achieves smoothing of coating, achieves a long life of the roll, enables high-speed coating, and can significantly improve productivity. It is an object of the present invention to provide a coating apparatus for manufacturing a magnetic recording medium.

[Means for solving the problem]

The coating apparatus for manufacturing a magnetic recording medium of the present invention, in order to achieve the above-mentioned object, a gravure roll having a spiral cell engraved on the surface thereof, and a long non-magnetic support formed on the gravure roll. In a coating apparatus for manufacturing a magnetic recording medium comprising a backup roll to be press-bonded, the surface of the gravure roll is roughened, and the top of the cell wall between the cells is substantially parallel to the axial direction of the gravure roll. A groove extending in the direction is formed.

[Action]

In the present invention, a groove is formed at the top of the cell wall formed on the surface of the gravure roll so as to extend in a direction substantially parallel to the axial direction of the gravure roll. The paint is also filled into the groove connected to the non-magnetic support at the position in contact with the top of the cell wall. Therefore, by the synergistic action of the cells provided between the cell walls and the microcells formed by the grooves extending in a direction substantially parallel to the axial direction of the gravure roll, the paint is applied evenly over the entire non-magnetic support.

〔Example〕

 Hereinafter, the present invention will be described based on specific examples.

As shown in FIG. 1, the coating apparatus for manufacturing a magnetic recording medium according to the present embodiment includes a gravure roll (1) having a cell pattern engraved on a surface thereof and a non-magnetic support (2). And (3) a backup roll to be pressed against
A filling blade (5) for supplying a paint (4) such as a liquid magnetic paint or a back coat paint into a cell provided on the surface of the gravure roll (1).

The gravure roll (1) is rotated in a tank (13) filled with the paint (4) to fill the paint (4) into a cell provided on the surface thereof by a filling blade (5). This is for transferring onto the magnetic support (2).
The gravure roll (1) is composed of a cylindrical roll (6) made of Fe or the like having relatively low hardness, as shown in FIG. 2, for example. The rotating shafts (7) and (7) are press-fitted and formed. In this embodiment, the roll (6) has a Rockwell hardness H _R C30 or a Vickers hardness Hv300.
STKM (carbon steel tube for machine structure) material was used.

As shown in FIG. 3, a cell wall (8) for forming a cell to be filled with the liquid paint (4) is formed on the outer peripheral surface of the roll (6) as a projection having a substantially trapezoidal cross section in the axial direction. Are formed in a spiral shape at a predetermined pitch. Therefore, between the adjacent cell walls (8) and (8), a hollow having a substantially trapezoidal cross section surrounded by the side walls (8a) and (8b) of the cell walls (8) and (8) is formed as a cell. Here, the paint (4) is filled. Further, a groove (hereinafter, referred to as a groove) connected to a direction substantially parallel to the axial direction of the gravure roll for forming minute cells for filling the coating material (4) is formed at the tip of the cell wall (8) at the top of the mountain. , A fine groove (9)) is defined as a groove having a substantially V-shaped cross section in a direction intersecting the direction in which the cell walls (8) are connected (in this embodiment, the axial direction of the roll (6)). A plurality are formed at a pitch. Therefore, the paint (4) is filled in the fine grooves (9), and these fine grooves (9) are filled.
Becomes a minute cell. The shape of the fine groove (9) is
There is no particular limitation, and the cross-section is substantially V
It may be in the shape of a letter or may be in the shape of a substantially circular arc in cross section.

Further, a plating layer (not shown) made of hard chromium is formed on the surface of the roll (6) for the purpose of forming fine cells for further filling the paint (4) and for improving the durability. Have been. The plating layer is formed by electroplating on the surface of the roll (6), which is formed into a fine irregular shape by honing the surface of the roll (6), and the irregularity is formed by the effect of increasing the current density in the convex portion of the electroplating. ing. Therefore, the depressions between the fine protrusions on the surface of the plating layer become fine cells for filling the paint (4).

On the other hand, the backup roll (3) presses a long non-magnetic support (2) such as a polyester film onto the surface of the gravure roll (1) and fills the cells provided in the gravure roll (1). The coating material (4) to be transferred onto the non-magnetic support (2) in an excellent manner. For example, an elastic body (11) made of rubber or the like is provided around a cylindrical roll (10) made of Fe or the like. Is formed. Therefore, the elastic force of the elastic body (11) covering the surface of the roll (10) causes the non-magnetic support (2) to come into close contact with the cell wall (8) on the surface of the gravure roll (1) and fill the cells. The coating material (4) is successfully transferred onto the non-magnetic support (2).

The backup roll (3) is provided so as to face the gravure roll (1), and rotates in opposite directions in synchronization with the gravure roll (1). Further, the backup roll (3) may be formed by forming an elastic body (11) on the surface of the roll (10) as in the above example, but the entire roll (10) is made of an elastic body. It may be configured.

The filling blade (5) is for supplying the paint (4) into large and small cells formed on the surface of the gravure roll (1), and the gravure roll (5) is provided on the supply side of the non-magnetic support (2). It is provided close to 1).

In the coating apparatus having the above configuration, the non-magnetic support (2) is pressed against the surface of the gravure roll (1) by the backup roll (3), and the first non-magnetic support (2) is moved between the backup roll (3) and the gravure roll (1). When passing in the direction of arrow A in the figure, the paint (4) filled in the cells provided on the surface of the gravure roll (1) by the filling blade (5) rotates the rolls (1) and (3). Is transferred onto the non-magnetic support (2). At this time, the paint (4) transferred onto the non-magnetic support (2) is applied over the entire surface of the non-magnetic support (2) as shown in FIG. This is because the cells formed between the cell walls (8) of the gravure roll (1) in contact with the non-magnetic support (2) and the plurality of fine grooves (9) provided at the top of the cell walls (8). This is due to the synergistic action of the microcells formed by the microcells and the microcells formed by the fine depressions formed on the surface of the plating layer. In this way, when the coating material (4) is applied over the entire surface of the non-magnetic support (2), the generation of a coating mass called a bead or a splash is eliminated, and the coating can be performed at a high speed. Becomes For example, when the coating is performed at 500 m / min, the coating can be continuously performed for about 5 days in the past, but can be continuously performed for 10 days in the present embodiment.

By the way, the above-mentioned gravure roll (2) is produced as follows.

First, as shown in FIG. 5 (a), the rotating shafts (7) and (7) are press-fitted into the center hole (6a) of a cylindrical roll (6) made of Fe or the like from the upper end surface and the lower end surface. I do.

Next, as shown in FIG. 5 (b), the rotating shafts (7) and (7) are welded to the rolls (6) and (6) to be integrated.

In this embodiment, the roll (6) and the rotating shaft (7),
Although they are separate members from (7), they may be formed integrally.

Next, as shown in FIG. 5 (c), a cell wall (8) for forming cells on the outer peripheral surface of the roll (6) is formed into a substantially trapezoidal cross section in a spiral shape along the axial direction. Form. This processing is performed by rotating the roll (6) and pushing it off with a die, so-called knurling processing. In this example, the height of the cell wall (8) was set to 0.15 mm.

As a result, a spiral cell pattern is formed on the surface of the roll (6).

Next, a fine groove (9) for forming a minute cell is formed at a tip portion corresponding to the top of the mountain of the cell wall (8). In order to form the fine groove (9), for example, a method such as cutting, laser processing, or rolling is used. In this embodiment, a micro-groove (9) was formed by using a thing like abacus ball and rolling the ball while applying pressure thereto.

The direction in which the fine grooves (9) are formed is, as described above, a direction substantially parallel to the axial direction of the roll (6). Also,
It is desirable that the groove depth of the fine groove (9) is larger than the thickness of a plating layer described later. In this way, even when plating is lost due to abrasion, the microgrooves (9) function as cells, so that the life of the gravure roll (1) can be extended.

In this example, the depth of the fine groove (9) was 17 μm and the width of the fine groove was 30 μm with respect to the plating thickness of 15 μm.

Next, the surface of the roll (6) on which the cell walls (8) and the fine grooves (9) are formed is roughened by liquid honing.
The height difference between the irregularities was 3 μm.

Liquid honing mixes fine abrasive grains with liquid,
This is a method of roughening the surface of the roll (6) by spraying the surface of the roll (6) using air pressure. The value of the surface roughness here is appropriately set according to the type of paint used, the thickness of the coating film, and the like. For example, when a coating film having a thickness of 1 μm or more is formed, the surface roughness is 3 to 5μ in ten-point average roughness Rz (value specified in JIS B 0601)
m and 2 to form a coating film having a thickness of less than 1 μm.
It is preferably 3 μm.

Then, hard chromium was electroplated thereon for the purpose of improving the durability of the roll (6) and forming micro cells.

As a result, as shown in FIG. 5 (e), the surface of the plating layer (12) becomes uneven due to the effect of increasing the current density at the projections of the electroplating. Therefore, in the plating layer (12), a plurality of fine cells are respectively formed between the adjacent minute projections.

As mentioned above, although the concrete example of the application device to which the present invention was applied was explained, the present invention is not limited to the above-mentioned example, and various changes can be made without departing from the spirit of the present invention. . For example, if a material having excellent wear resistance is used for the roll (6) of the gravure roll (1), it is not necessary to perform chrome plating, and the gravure roll (1) can be used as it is. Of course, this may be honed to roughen the surface to form fine cells.

〔The invention's effect〕

As is clear from the above description, in the present invention, a groove is formed at the top of the cell wall of the gravure roll in contact with the non-magnetic support in a direction substantially parallel to the axial direction of the gravure roll that becomes a microcell. Therefore, a magnetic paint or a back coat paint can be applied also on the nonmagnetic support corresponding to the top of the cell wall, and the cell provided between the cell walls and the axial direction of the gravure roll can be applied. A smooth coating can be performed by a synergistic action with a microcell formed of a groove extending in a direction substantially parallel to the above.

Therefore, according to the coating apparatus for manufacturing a magnetic recording medium of the present invention, the lump of the paint is not scattered, the quality can be improved, and high-speed coating can be realized, and the productivity can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a coating apparatus for manufacturing a magnetic recording medium to which the present invention is applied. FIG. 2 is a schematic perspective view of a gravure roll, and FIG.
The figure is an enlarged perspective view of a main part showing a roll surface in an enlarged manner. FIG. 4 is an enlarged sectional view of an essential part showing a non-magnetic support to which a coating material is applied by the coating device of the present embodiment. 5 (a) to 5 (e) sequentially show the steps of manufacturing a gravure roll, and FIG. 5 (a) is a schematic perspective view showing a rotating shaft press-fitting step, and FIG. b) is a schematic perspective view showing a welding step, FIG. 5 (c) is a schematic perspective view showing a cell wall forming step, and FIG. 5 (d) is a schematic perspective view showing a fine groove forming step. FIG. 5 (e) is an enlarged sectional view of a main part showing an electroplating step. DESCRIPTION OF SYMBOLS 1 ... Gravure roll 2 ... Non-magnetic support 3 ... Backup roll 4 ... Paint (magnetic paint, back coat paint) 5 ... Filling blade 8 ... Cell wall 9 ... Fine groove

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Aoya 6-5-6 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Magne Products Co., Ltd. (56) References JP-A-1-119374 (JP, A) JP-A-54-154435 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 5/84 H01F 41/14

Claims (1)

(57) [Claims] 1. A coating apparatus for manufacturing a magnetic recording medium, comprising: a gravure roll having spiral cells engraved on a surface thereof; and a backup roll for pressing a long non-magnetic support onto the gravure roll. In the magnetic recording method, the surface of the gravure roll is roughened, and a groove is formed at the top of the cell wall between the cells in a direction substantially parallel to the axial direction of the gravure roll. Coating equipment for manufacturing media.