KR19980042573A - Coating device - Google Patents

Abstract

It is an object of the present invention to provide a coating apparatus capable of forming a magnetic layer having a flat surface without thickness non-uniformity with good working efficiency. The object is a laminate in which the magnetic paint 3A is coated through the extrusion die 1 and is composed of layered flat magnets 15 layered downstream of the die and close to the uncoated side of the support 19. A magnetic field generator 12a having a structure is obtained by an apparatus inclined at 45 ° to 85 ° with respect to the running direction R of the support. By taking such an arrangement, the coating surface of the magnetic layer 3 becomes flat without having thickness nonuniformity.

Description

Coating device

The present invention relates to a coating apparatus configured to coat a magnetic layer on a magnetic recording medium to be used, for example, as an audio tape or a video tape.

Recording media used in audio tapes, video tapes, and computer systems disperse magnetic powders, binders, and various additives in organic solvents, and then knead these materials to form a magnetic paint, which is coated on a non-magnetic support and the magnetic layer on the support. It includes a so-called coated magnetic recording medium produced by drying to form a. Such recording media are excellent in productivity and versatile in use.

Conventional magnetic layer coating methods include a gravure coating step using gravure rolls, but in this method the coating speed is insufficient and the coating thickness is not uniform. In order to solve this problem, a die coating has recently been employed using an extrusion die in which a magnetic paint is extruded through a slit to be coated on a support, which is controlled by the amount of coated paint and uniformity of the coating. It has advantages because it can increase the coating speed while maintaining it.

In the manufacture of coated magnetic recording media, it is common to perform a surface smoothing process on a coated substrate that is still wet after coating the magnetic paint on the nonmagnetic substrate to improve the magnettoelectric conversion characteristics of the product. . If the surface of the magnetic layer formed on the nonmagnetic substrate does not have sufficient surface properties, especially if the coating film has a nonuniform thickness due to poor coating, the recording medium thus produced will have insufficient signal recording properties. To solve this problem, it is universally known that a bar smoother acting as a surface smoothing means is brought into mechanical contact with the coating surface to smooth the surface.

In particular, in the die using the extrusion die described above, coating is performed while the die is held stationary, and thus surface roughness composed of fine longitudinal lines in the direction in which the nonmagnetic support travels is easily generated on the surface of the coating layer. do. The severity of this surface roughness depends on the magnitude of the shear force of the paint received in the coating unit, and is greater in the case of a die contact coating in which the die is in contact with the support than in the case of a die lift coating in which the die does not contact the support. In addition, surface roughness occurs more easily as the magnetic powder becomes finer to make a magnetic recording medium more suitable for high density recording, because the fineness of the powder enhances the cohesion of the formed paint. This effect is more pronounced in die coating.

In the conventional die coating, in order to eliminate the above-mentioned disadvantages, in particular in die lift coating, it is necessary to properly combine the die and bar smoothers so that the coating layer is smooth without bonding.

In addition, the method of smoothing the coating layer with a bar smoother has the following three problems and can be further improved.

(1) The foreign material layer is captured by a smoother in contact with the magnetic paint to form a line on the coated magnetic layer.

(2) Once each coating is completed and the smoother is wound on a roll, it is necessary to clean the surface of the bar, which reduces the workability of the device.

(3) In the absence of paint, both margins of the support contact the edges of the smoother and the scratches from the exposed edges are dried or the coating is easily weakened due to the paint material attached to the bar.

In order to replace such a conventional bar smoother, Japanese Patent Laid-Open No. 60-202542 discloses a method of positioning a smoother using a magnet downstream of a roller to coat a magnetic paint. Using a smoother with a magnet seems to be able to completely smooth the surface coated with the magnetic paint, but the actual smoothing is insufficient in this method because the magnet is simply configured to move perpendicular to the direction of travel of the support. In addition, in this method, since the magnetic paint is coated with a roll, the coating speed is slow as described above, and the uniformity of the coating surface is also easily damaged.

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above circumstances, and aims to provide a coating apparatus that solves the problems inherent in the conventional smoother and enables to form a coating having a flat surface and no change in thickness at a high speed. do.

The present inventors have studied the problems inherent in the conventional method described above to obtain a coating apparatus having excellent workability without coating line having no line on its coating surface and coating thickness non-uniformity at both margins. . In the present invention, in the extrusion die coating in which the magnetic paint is extruded through a slit to be coated on a continuous running support, a specific number of permanent portions each having N and S poles alternately layered in the running direction of the support to form a plate-like structure. It is based on a magnet unit comprising a magnet element, said magnet unit having a coating just formed so that its long axis is inclined at a certain angle with respect to the direction of travel of the support, which is still wet and below the uncoated surface side of the support before magnetization. Located.

The present invention provides an extrusion die that allows the magnetic paint to be extruded to be coated onto a continuously running substrate, and a smoothing of the surface of the support, which is formed in the manner described above and coated with the magnetic paint which is still wet, by the action of a magnetic field. A coating apparatus comprising a group is provided. The smoother takes a laminated structure composed of a plurality of magnet elements positioned in the form of layers such that the N pole and the S pole are alternately arranged in the running direction of the support, and have an inclination angle with respect to the running direction of the support and parallel to the coating surface of the support. It is located in the plane facing the opposite side.

In the coating apparatus according to the invention, the magnetic material is extruded onto a support in an extrusion die and coated thereon, and a smoothing device having a laminated structure composed of a plurality of magnetic elements arranged in layers positioned at an inclination angle with respect to the running direction of the support. The just formed coating surface, which is still wet, is smoothed by the action of the magnetic field. In particular, since the action from the magnetic field (magnetic field) generated by the smoother has an inclination angle with respect to the running direction of the support, the coated and yet wet magnetic material flows along the direction in which the magnetic field acts, and the flow of such magnetic material It contributes to the smoothing (flattening) of the coating film of the magnetic material not only in the running direction of the support but also in the direction perpendicular to the running direction of the support or in the width direction of the support. The apparatus of the present invention, which can smooth the coating surface in the manner described above, maximizes the advantages of the high speed coating inherent in extrusion die coating.

1 is a schematic plan view of a smoother unit of a coating apparatus according to a first embodiment of the present invention;

FIG. 2 is a sectional view taken along the line II-II of FIG. 1; FIG.

FIG. 3 shows the angle at which the magnetic field generator of the coating apparatus can be attached, a cross-sectional view of the smoother unit (the position of the smoother unit relative to the support of FIG. 1 is rotated by 90 ° in this figure).

4 is an enlarged cross-sectional view of the smoother unit taken along the line IV-IV of FIG.

Fig. 5 is a schematic cross sectional view of the coating apparatus showing the coating unit and the smoother unit highlighted to perform coating by die lift coating;

Fig. 6A is a plan view showing a smoother unit of the coating apparatus according to the second embodiment of the present invention, and Fig. 6B is a sectional view taken along the line b-b of Fig. 6A.

7 is a schematic cross-sectional view of the coating apparatus showing the coating unit and the smoother unit highlighted.

8 is a graph showing the maximum roughness of the coated surface as a function of the number of stacked magnets.

<Description of the code | symbol about the principal part of drawing>

1: extrusion die

3: magnetic layer

3A: magnetic paint or magnetic paint

3a: coated surface

4: slit

5: front lip

6: rear lip

7A, 7B: York

8, 15: magnet

10, 12A: magnetic field generator

12: first magnetic field generator

13: second magnetic field generator

16: bead

18: coating surface roughness

19: support

F, f: magnetic lines

θ: tilt angle

R: driving direction

In the coating apparatus of the present invention, as described above, it is preferable that the smoothing device having a laminated structure composed of a plurality of magnetic elements is positioned at an inclination angle of ± (45 ° to 85 °) with respect to the running direction of the support. If the smoother is positioned outside the angle in the above range, the action from the magnetic field generated by the laminated magnet element is weakened and the flow of the magnetic film on the support is reduced, making the coating smoothing operation difficult.

If a smoother consisting of a plurality of magnet elements arranged in the form of layers comprises first and second laminated magnet structures continuously positioned below the travel support, their inclination angle with respect to the travel direction of the support is in this range or ± (45 °). To 85 °) and take different angles.

It is preferred that 20 to 100 plate magnet elements are arranged in the form of layers to form a smoother.

The magnet element is preferably a permanent magnet to form a smoother, but an electromagnet may be used instead.

The effect of the invention is evident when the magnetic material is coated onto the support while keeping the extrusion die and the support spaced apart from each other to avoid direct contact.

<Example>

Examples of the present invention are described below, but the scope of the present invention is not limited to these examples.

1 is a schematic plan view of a smoother unit of a coating apparatus according to a first embodiment of the present invention. 2 to 4 show the construction of the smoother unit in the above embodiment, the phenomenon observed during the operation of the unit and the theory explaining the operation.

1 shows a magnetic field generator 12A located downstream of the coating unit to release a magnetic paint (not shown in this figure) in a plane parallel to and spaced apart from its uncoated surface side with respect to the support 19. Shows that. The support 19 has a magnetic paint coated with an extrusion die, which will be described later, and conveys a still wet magnetic layer 3 formed thereon, and travels in the direction indicated by R (or x-axis direction).

The magnetic field generator 12A constituting the part of the magnetic smoother has 20 to 100 or in particular 50 permanent magnet elements that take the form of a plate-like structure arranged in the form of layers along the running radius R of the support 19. 15). The magnetic field generator 12A is positioned with respect to the traveling direction R such that its longitudinal axis is inclined at an angle of + θ (for example, 45 °). Here, the clockwise inclination is represented by + θ and the counterclockwise is represented by -θ.

The magnetic field generator 12A comprises, for example, 50 permanent magnet elements 15 (hereinafter referred to as magnets) made of a neodium alloy (maximum energy amount of 46 MGOe) arranged in the form of layers. These magnetic elements are arranged with each other such that adjacent N poles and S poles are alternately positioned in the direction R, as shown in Fig. 2 (cross-sectional view of the magnetic field generator taken along the line II-II of Fig. 1). The side surface is fixed by the yoke 14 and the front surface (side surface facing the support body 19) is covered with the protective film 14a. The protective film 14a is located in close contact with the support 19 or spaced apart from the support 19 by several millimeters or less, and is generally parallel to the support in the x- and y-axis directions.

Further, as shown in Fig. 3, the magnetic field generator 12A is a solid line in which the longitudinal axis is inclined at an angle of θ from a position shown by an imaginary line whose longitudinal axis is perpendicular to the running direction R of the support 19. It may also be rotated backwards to move up to the position shown, the tilt angle being adjustable.

In the manner described above, the plate magnets 15 are located side by side in a multi-layered manner, and contact lines formed between these magnets 15 and adjacent magnets 15 as shown in Fig. 4 (the same as A in Fig. 3). Magnetic field lines F are radiated in a direction B perpendicular to the direction B). These lines of magnetic force F act on the magnetic paint 3 coated on the opposite side via the support 19. As a result, the magnet 15, which has just been formed and is still wet, is provided with a maximum magnetic field density such that the maximum magnetic field density is provided so that the magnetic field of the magnetic field lines F radiated by the magnetic field generator 12A forms a raised portion. Displaced towards the area between them (the contact area of two adjacent magnets). Thus, the paint beads 16 are formed on the coating surface 3a.

The bead 16 is in the form of a continuous line of raised profile, which is convex in the same direction as the magnetic field generator 12A, for example with respect to the running direction R of the support, i.e., the direction in which the contact line between adjacent magnets extends ( 45 ° with respect to R). These beads 16 fall downward on the coating surface of the support when the support 19 runs, contributing to the smoothing of the coating surface.

During this process, fine lines of recesses and rises appear on the coating surface, but these rises fall towards the recesses and the same process is repeated for each pair of adjacent magnets. Therefore, the whole coating surface of the support body in the width direction and the travel direction can be made flat.

In order to obtain a perfect smooth portion, it is important to position the magnetic field generator 12A at an inclination angle of ± (45 ° to 85 °) with respect to the running direction of the support 19. Several experimental results show that positioning the magnetic field generator 12A at an angle of inclination within this range is necessary to completely smooth the wet surface coated with the magnetic paint 3A.

The smoother of this embodiment is most effective when the magnetic paint is coated through an extrusion die, in particular a magnetic extrusion die (hereinafter referred to as a die).

There are two different methods of coating using this die, one of which is a die lift coating that coats the paint while keeping the die and the support spaced apart from the other and the other coating the paint with the die and the support in close proximity to each other. Die contact coating. The coating of the present invention can be applied to both cases, but the construction is more suitable for die lift coating because the surface roughness in the form of fine stripes is easily generated on the coating surface provided by the die lift coating. In the case of a die contact coating, the contact of the die with the support surface during the coating will significantly smooth the surface.

5 is a schematic cross-sectional view showing the main part when using a non-contact extrusion die.

As shown in this figure, the die 1 has a 160 mm wide slit after the front lip 5 and the rear lip 6 are properly adjusted, and the rear lip 6 stores the reservoir for storing the paint. It has a pocket 2 acting as a. A slit 4 (coating width for example 110 mm and a slit gap for example 260 μm) is formed between the pocket 2 and the release mouse, and the paint 3a is discharged through this slit 4 do.

The magnetic field generator 10 has a gap of a certain width and is located opposite the die 1. This magnetic field generator 10 is sandwiched between two yokes 7A and 7B made of low carbon steel equivalent to S20C forming a closed magnetic circuit (with a maximum magnetic flux density of 3800 G actually measured at the tip). Magnets 8 (in this figure the magnets are permanent magnets made of neodium alloy but electromagnets may be used instead).

The support 19 (film (for example 127 mm wide and 14.5 μm thick), coated with a film and made of PET for VHS, is die without contacting either of the two elements as shown in FIG. It travels through the gap between (1) and the magnetic field generating body 10, and accommodates the coating of 3 A of magnetic paints in the state conveyed in the vertical direction.

Magnetic paint 3A is sufficient to form a coating having a dry thickness of, for example, 1 to 2 μm, on a support conveyed at a speed of, for example, 400 m / min by a tension of 3 kg / width, for example. It is fed into the pocket 2 by a pump (not shown) at a speed. The smoother unit including the magnetic field generator 12A described above is located adjacent thereto downstream of the coating die 1.

By operation of these elements, a smoothed magnetic film 3 is formed on one surface of the support 19.

In the coating apparatus of the present invention, as described above, the magnetic field generator 10 is located on the opposite side of the die 1 with the support 19 inserted therebetween, and the yoke 7A, 7B from the magnet 8 is provided. The magnetic paint 3A discharged from the die 1 by the action of the magnetic force line f radiated through) is attracted by the magnetic field generator 10 to be discharged toward the surface of the support 9 and coated thereon. Therefore, the adhesion of the coating is excellent and the coating material 3A does not fall during the coating.

In the manner described above, the magnetic paint 3A is coated on the support 19 to be smoothed and dried, and the coating sheet thus formed is cut into strips having a specific width so that the magnetic layer 3 is formed. And magnetic tape each containing. In addition, the surface of the support opposite the magnetic coating surface may have a back coating layer, and the magnetic layer may have an overcoating layer thereon. The surface of the support may have an intermediate layer or base layer to improve the adhesion performance of the magnetic layer on the support.

In a magnetic recording medium such as a magnetic tape provided in accordance with the present invention, the magnetic powder used as the material of the magnetic paint (or magnetic layer) may include any of known powders and may include an oxidized magnetic powder or a magnetic metal powder. It may be.

The oxidizing magnetic powder is for example γ-Fe ₂ O ₃ , γ-Fe ₂ O ₃ containing Co, Fe ₃ O ₄ , Fe ₃ O ₄ containing Co, Co coated γ-Fe ₂ O ₃ , Co coated Fe ₃ O ₄ , CrO ₂ , and the like.

The metal magnetic powder is, for example, Fe, Co, Ni, Fe-Co, Fe-Ni, Fe-Co-Ni, Co-Ni, Fe-Co-B, Fe-Co-Cr-B, Mn-Bi, Mn -Al, Fe-Co-V, and the like, and metal components such as Al, Si, Ti, Cr, Mn, Cu, and Zn may be added to the metal powder in order to improve various properties of these materials. Hexagonal ferrites such as barium or iron carbides and iron nitrides such as Fe ₅ C ₂ can also be used.

The elements of other compositions required for the production of the magnetic recording medium according to the present invention may include known elements used for similar purposes when providing a conventional coated magnetic recording medium.

For example, the binder that can be added to the magnetic layer is a modified or unmodified vinyl chloride resin, a vinyl copolymer such as a vinyl acetate copolymer, a polyurethane resin such as a polyester polyurethane resin or a polycarbonate polyurethane resin, or a polyester The resin may be included alone or in combination thereof. In addition, thermoplastic resins such as nitrocellulose, thermoplastic resins such as phenoxy resins, or resins used for specific applications, thermosetting resins, reactive resins, and resins cured when exposed to an electron beam may be used as an additive.

The groups introduced for the modification of the resins described above may include -SO ₃ M, -OSO ₃ M, -COOM, -PO (OM ') ₂ and the like (wherein M is an alkali metal atom such as Na) , M 'represents an alkali metal atom or an alkyl group).

In addition to the magnetic powder and the binder, an additive such as a lubricant, an abrasive or an antistatic agent may be appropriately added to the magnetic layer. These additives may include known materials used for the same purpose and are not limited to specific materials.

Further, a dispersant such as lecithin, an antistatic agent such as carbon black, an abrasive such as alumina, and a corrosion inhibitor may be appropriately added to the magnetic layer. These dispersants, antistatic agents, abrasives and corrosion inhibitors may include known materials used for the same purpose and are not limited to specific materials.

In addition, the magnetic layer is usually formed on the support, and the usable support is, in addition to polyethylene terephthalate, polyester such as polyethylene-2 and 6-naphthalate, polyolefin such as polyethylene and polypropylene, cellulose triacetate and cellulose diacetate and cellulose butyl Cellulose by-products such as late, vinyl resins such as polyvinyl chloride and polyvinylidene chloride, and plastics such as polyamide and polyamide imide and polycarbonate.

To form a magnetic layer on a nonmagnetic support, the magnetic powder is combined with a binder, lubricant, organic solvent, and various other additives to make a magnetic paint, which is coated on the nonmagnetic support. The back coat layer or top coat layer, which may be added as appropriate, may be prepared from any conventional materials and methods.

6A and 6B show a smoother unit of the coating apparatus according to the second embodiment of the present invention. FIG. 6A is a plan view and FIG. 6B is a sectional view of the same unit taken along line b-b of FIG. 6A. This corresponds to that shown in FIG.

As shown in this figure, in this embodiment the magnetic field generator 12 which is first seen when viewed from the position of the coating unit is located side by side in front of the second magnetic field generator 13 located downstream thereof. In this embodiment, each magnetic field generator includes a permanent magnet 15 in the form of a plate, similar to the first embodiment described above, stacked transversely in, for example, a 25 layer structure. The first magnetic field generator 12 is rotated clockwise to have an inclination angle of + θ = 65 ° with respect to the running radius R of the support 19, and the second magnetic field generator 13 is -θ = 85 °. Rotate counterclockwise to have a tilt angle.

In addition, the smoother of this embodiment is suitable for mass production and allows a substrate with a width of, for example, 620 mm to be stretched at a speed of, for example, 400 to 900 m / min, for example by a force of 12 kg during travel.

The first magnetic field generator 12 is located between the guide rollers 11a and 11b, and the second magnetic field generator 13 is located between the guide rollers 11b and 11c, and these magnetic field generators and the support 19 The uncoated surfaces of) are proximal to each other in parallel to form a gap C having a constant width of, for example, 0.5 mm or less.

Here, it is important for the first and second magnetic field generators 12 and 13 to have an inclination angle within a range of ± (45 ° to 85 °) with respect to the running direction of the support 19, and these inclination angles are shown in various experimental results. When it is in this range, the surface of the wet state can be coated with the magnetic paint 3A so that the surface still has no lines and has a non-uniformity on both margins of the support, and can be smoothed satisfactorily, so that the coating can be performed with good working efficiency. Can be.

FIG. 7 is a cross-sectional view of the main elements including the die 1 and the magnetic field generator 10 of the coating apparatus for carrying out the coating method of this embodiment.

The coating apparatus of this embodiment can have a larger dimension than the apparatus of the first embodiment. Thus, the die is for example 700 mm wide allowing for a coating of 610 mm wide, for example. Since the structure and operation of the die 1 and the magnetic field generator 10 are the same as in the first embodiment, description thereof will be omitted.

In this embodiment, immediately after the magnetic paint is coated using the die 1, the surface 3a of the magnetic layer 3 smoothed using the first magnetic field generator 12 is the first magnetic field generator 12. The second magnetic field generator 13 is rotated in such a manner as to give an inclination angle that is opposite to the inclination angle of.

Specifically, the bead 16 shown in FIG. 4 receives magnetic lines of force opposite the directions from the first and second magnetic field generators 12, 13, so that the flow of liquid magnetic paint is supported by the support 19. It occurs in several directions on the surface of the which further promotes smoothing of the coating. The above-described feature according to the configuration with a plurality of magnetic field generators 12 and 13 used in combination makes the magnetic coating on the support completely smooth due to the properties of the support, or the magnetic material of the magnetic paint to be coated. Due to the properties or viscosity properties, the support will not be allowed to smooth enough when processed in a coating apparatus using only a single magnetic field generator 12A as shown in FIG.

Next, the case where the device of the above embodiments is actually applied to the magnetic coating will be described.

Fig. 8 is a plate shape in which the maximum surface roughness SRmax of the magnetic layer 3 formed on the support by coating constitutes the magnetic field generator 12A of the first embodiment (the inclination angle? Relative to the running direction of the support is + 45 °). It is a graph shown as a function of the number of magnets.

Tolerances of surface roughness (approximately 110 nm) applicable to VHS electron conversion for the maximum surface roughness (150 nm) of magnetic coatings provided in the device without the use of magnets are obtained by using 20 planar magnets in the form of layers. It can only be obtained by magnetic coating provided by the coating device. In addition, as the number of magnets increases to 50, the maximum surface roughness of the resulting coating decreases to about 96 nm, and as the number of magnets increases further, the surface roughness is the level of the magnetic coating provided by the device using the smoother as described above. As close as possible to, however, an unacceptable change is observed as the number of magnets increases further. These can be seen by observing the curve 18. It is preferable that the number of magnets laminated | stacked from the said description is 20 or more and 100 or less.

From the results of FIG. 8, the maximum surface roughness of the magnetic coating provided by the device using 50 magnets in the form of layers is about 96 nm, which is considered to be superior to all conventional methods of smoothing the magnetic coating. It is almost equal to the surface roughness of the magnetic coating provided by the device. This fact shows that the method of the first embodiment of smoothing the magnetic coating has almost the same performance as that of the bar smoother, because the device of the first embodiment has 50 magnets stacked in the form of layers. This also applies to the apparatus of the second embodiment, in which two magnetic field generators preferably have a total of 50 magnets (25 magnets for each magnetic field generator) in the form of layers. .

Coating in this example was performed under the conditions set forth in Tables 1a and 1b.

Coating unit Classification Item First embodiment Second embodiment Die (1) Coating method Contactless extrusion coating Die width 160 mm 700 mm Coating width 110 mm 610 mm Slit gap 260 μm 260 μm Magnetic field generators (1) Magnet (8) Neodium Alloy Magnet (30 MGOe) York (7A, 8A) Material: Low Carbon Steel (S20C) Magnetism: 3800 Gauss at York Tip Magnetic paint (3A) Paint for VHS (magnetic powder: Fe and Fe compound) Binder: vinyl chloride polymer, polyurethane filler: alumina, etc. Support (19) Polyethylene Terephthalate Support for VHS width 127 mm 620 mm thickness 14.5 μm 14.5 μm Coating condition Tension applied to the support 3 kg 12 kg Traveling speed 400 m / min 400-900 m / min Gap between substrate and die 1 mm 1 mm Gap between substrate and yoke 0.5 mm 0.5 mm

Magnetic field generator to smooth the coated surface (magnetic smoothing machine) Classification Item First embodiment Second embodiment Magnet (15) Neodium Alloy Magnet (46 MGOe) Effective width of magnetic force 300 mm 850 mm Number of magnets in layer form 50th floor x 1 unit 25th floor x 2 units Mounting condition Angle (θ) relative to the direction of travel of the substrate +90。, +45。 First magnetic field generator (12): +65. Second magnetic field generator (13): -85. location Installed below the rear (uncoated) surface of the support with a gap of 0 to 0.5 mm, may contact the rear surface being coated while the substrate is running

In these examples, the magnetic field generator measured various properties each time its angle was changed with respect to the running direction of the support, and a support or smoothing treatment treated with a device using a bar smoother or a device deemed to have the best performance. The same measurement was performed on the support which was not. The results are shown in Table 2 (showing video characteristics, tape coated for VHS was used as a reference).

Item / Sample One 2 3 4 5 Magnet angle 90。 Magnet angle 45。 Magnet angle (+65。, -85。) Bar smoother Non-smoothing RF-OUT (dB) -1.1 -0.8 -0.7 -0.6 -2.3 SRmax (nm) (TD) 128.75 96.25 95.32 95.0 151.25 SRz (nm) (TD) 101.25 81.25 80.14 79.25 117.0 SRa (nm) (TD) 7.3728 6.9324 6.2250 5.8210 13.3004

From the measurement results, the tape produced when the magnetic field generator was inclined at + 45 ° or + 65 ° to −85 ° with respect to the running direction of the support was found in the smoothing machine when the same magnetic field generator was positioned perpendicular to the running direction of the support. It is shown to be much better than the properties of the treated and unsmoothed tapes, and it can be seen that it has a smooth surface, like the surface from the bar smoother, which is considered the best smoother.

From the above results, the device of these embodiments provides the following excellent effects.

(1) The smoothness of the surface coating is improved, so that the quality standard of the product remains stable.

(2) No line is formed on the support so that the high quality of the product remains stable.

(3) Cracks do not form on both clearances that do not accommodate the coating, eliminating the possibility of line formation and uneven coating.

(4) Non-stop operation of the same device is possible since the device does not need to be cleaned after being rolled up on a roll (which reduces the work required for coating).

As described above, according to the present invention, in addition to the extrusion die, a magnetic unit is required to smooth the wet magnetic layer, in addition to the extrusion die, in accordance with the present invention. In addition, it ensures good working efficiency and provides an excellent coating device in terms of high speed operation.

While embodiments of the invention have been described, these embodiments may be modified in various forms within the spirit of the invention.

For example, the magnetic field generators 12, 12A, and 13 that smooth the wet coated surface may be located proximate to, but spaced apart from, the uncoated surface of the support 19, or may be located in direct contact with the same die. Alternatively, these magnetic field generators may be located proximate to the coating surface of the support.

Further, in the above embodiment, the magnets 15 constituting the magnetic field generators 12, 12A, 13 are stacked together to generate a magnetic field F having the same magnetic flux density over their range, but the magnetic fields are It may be changed along the driving direction. That is, the upstream flat magnet 12 is located coarser while the downstream flat magnets are more tightly positioned so that the upstream and downstream magnets exert different magnetic forces around them.

In addition, in the above embodiments, a single magnetic field generator or two magnetic field generators in a combined form are used, but three or more magnetic field generators may be used, and the number of the flat magnets 15 may be in the range described in the above embodiments. It is not limited. The number of magnetic field generators and the number of magnets included in the individual magnetic field generators may be changed according to the required characteristics of a given magnetic recording medium or the magnetic or viscosity characteristics of a given magnetic paint, so that, for example, the single The required result can be obtained by using a magnetic field generator or by using a plurality of identical magnetic field generators as shown in FIG.

In addition, the angle which the magnetic field generators 12, 12A, 13 take with respect to the running direction of the support body 19 is not limited to the range described in the above embodiments, and may take an appropriate value as necessary. For example, the magnetic field generator may be fixed during use but may be altered to rotate to change its angle within a certain angle during use.

In addition, the shape and structure of the magnetic field generators 12, 12A, 13 are not limited to those described in the above embodiments, and may be appropriately changed as necessary, and the shape and material of the die 1 and the magnetic field generator are also required. Can be changed according to. The magnet is not limited to the permanent magnet and may include an electromagnet. In addition, the magnetic field generator 10 described above does not necessarily need to be added, and may be coated using only a conventional extrusion die.

The present invention is not only suitable for the above-described magnetic tape, but also for all magnetic recording media in the form of a tape, and magnetic disks such as floppy disks or the like that are produced after the mother plate is cut into individual pieces of a specific type or It is also suitable for the production of magnetic sheets such as magnetic cards.

As described above, according to the present invention, the magnetic material is extruded onto the support by means of an extrusion die and coated thereon, and the resulting coating is made up of a plurality of magnets which are inclined with respect to the running direction of the support while still wet. Provided in a smoother taking the structure, the action of the magnetic field (magnetic flux) of the smoother takes a direction inclinedly intersecting the running direction of the support, the coated magnetic material flows in the same direction as the direction of action of the magnetic field, The thickness not only moves in the direction in which the support runs, but also flows in a direction perpendicular to the direction or in a direction corresponding to the width of the support. Thus, the present invention maximizes the advantages of high speed coating and other features in extrusion die coating.

Thus, applying the present invention to making a magnetic tape for video or audio results in that the magnetic layer formed on the surface of the tape support does not actually have a thickness non-uniformity, thereby providing a substantially flat surface, thereby providing magnetic property electron conversion and surface It is possible to produce a magnetic tape of good quality which is excellent in shape.

Claims (5)

A coating apparatus comprising an extrusion die for extruding a magnetic material on a support continuously running to coat a magnetic material, and a smoother for smoothing the surface just formed and coated with the magnetic material, which is still wet, by the action of a magnetic field. A stack structure consisting of a plurality of magnets in which the N poles and the S poles are alternately arranged in the running direction of the support, and acting as a smoother, is opposite the coating surface of the support in a plane parallel to the support and inclined with respect to the travel direction of the support. Coating device, characterized in that located. The coating apparatus according to claim 1, wherein the laminated structure composed of a plurality of magnets is inclined by ± (45 ° to 85 °) with respect to the running direction of the support. The coating apparatus according to claim 1, wherein the plate magnets constituting the smoother are stacked side by side in 20 to 100 layers. The laminated magnet according to any one of claims 1 to 3, wherein the laminated structure consisting of a plurality of magnets includes first and second magnet laminated structures continuously positioned along the running direction of the support, and the laminated magnet with respect to the running direction of the support. Coating device, characterized in that the inclination angle of the structures are different. The coating apparatus according to claim 1, wherein the magnetic material is coated on the support while the extrusion die is kept spaced apart from the support.