JPH0620274A - Method and apparatus for producing magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a high quality magnetic recording medium in which magnetic powder is oriented obliquely with no disturbance in magnetic coating of a magnetic recording medium. CONSTITUTION:A magnetic recording medium 2 travels through a solenoid coil 1 having a bent generating a field substantially in same direction in the traveling region of the magnetic recording medium 2 upon current supply. Alternatively, the solenoid coil may have a plurality of bents and the degree of bent may increase gradually along the traveling direction of the magnetic recording medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium manufacturing method and a magnetic recording medium manufacturing apparatus for orienting magnetic powder contained in a magnetic coating film of a magnetic recording medium obliquely with respect to the surface of the magnetic coating film. It is a thing.

[0002]

2. Description of the Related Art In general, the mainstream of magnetic recording is a method using magnetization in the longitudinal direction of a magnetic recording medium. However, if an attempt is made to further improve the recording density by this method, the demagnetizing field in the medium increases, and thus the recording density is limited, and the recording density cannot be improved so much. In other words, although this method improves the characteristics in the long wavelength region,
It has a drawback that the characteristics in the short wavelength region are inferior.

For this reason, a perpendicular magnetic recording system has been conventionally proposed in which recording is performed by magnetization in the thickness direction of a magnetic recording layer of a magnetic recording medium. According to the perpendicular magnetic recording method, the demagnetizing field becomes smaller as the recording density becomes higher,
In particular, it is known that high-density recording and short-wavelength recording are superior to the above-mentioned recording by in-plane longitudinal magnetization.

However, when the acicular magnetic powder or the like is oriented in the direction perpendicular to the magnetic recording layer, the characteristics in the short wavelength range are improved, but the characteristics in the long wavelength range are deteriorated. There is. Therefore, there has been proposed an oblique alignment technique capable of improving each of the shortcomings of the longitudinal longitudinal recording method and the perpendicular magnetic recording method and exhibiting a high output from a long wavelength region to a short wavelength region.

In the case of the coating type magnetic recording medium, the oblique orientation technique improves the electromagnetic conversion characteristics by orienting the magnetic powder in the magnetic coating film in an oblique direction with respect to the surface of the magnetic coating film. It is intended to exert a high output over a wavelength range to a short wavelength range. In addition to the coating type magnetic recording medium, there is also an evaporation type magnetic recording medium in which an oblique vapor deposition film is formed by obliquely evaporating Co—Cr or the like. Since it is necessary to manufacture using an apparatus such as an apparatus or a sputtering apparatus, the manufacturing cost is inevitably high, which is disadvantageous as compared with the coating type magnetic recording medium. Therefore, it is desirable that the coating type magnetic recording medium be obliquely oriented.

As a method of manufacturing a coating type magnetic recording medium by the above-mentioned oblique orientation, a pair of magnets are inclined at a predetermined angle with respect to the magnetic coating surface of the magnetic recording medium to generate an oblique magnetic field. A method of tilting the magnetic powder in the magnetic coating film obliquely with respect to the surface of the magnetic coating film by a magnetic field is mentioned.

[0007]

However, when the magnetic recording medium is manufactured by such a method, the magnetic field on the low angle side (the in-plane direction of the magnetic coating film is 0 degree, and the perpendicular direction is 90 degrees). In this case, the low angle means about 0 degree to 30 degrees), and a steep angle magnetic field is applied to the surface of the coating film, which causes disorder of the magnetic powder. In addition, there is a problem that the device becomes large in size and costly.

Therefore, the present invention has been proposed in view of such conventional circumstances, and the magnetic powder in the magnetic coating film of the magnetic recording medium can be obliquely oriented without disturbing, and the quality is good. It is possible to manufacture magnetic recording media, and
It is an object of the present invention to provide a magnetic recording medium manufacturing method and a magnetic recording medium manufacturing apparatus that can be implemented inexpensively and easily.

[0009]

In order to achieve the above object, a method of manufacturing a magnetic recording medium according to the present invention is a magnetic recording medium in which a magnetic recording medium is run in a solenoid coil to orient magnetic powder in a magnetic coating film. In the method of manufacturing a recording medium, the solenoid coil has a bent portion, and the magnetic field direction generated by the solenoid coil is substantially the same in the traveling area of the magnetic recording medium.

At this time, the solenoid coil may have a shape having a plurality of bent portions, or the bending degree of the plurality of bent portions may be gradually increased along the traveling direction of the magnetic recording medium.

Further, the present invention is a magnetic recording medium manufacturing apparatus which has a solenoid coil to which an electric current is supplied and orients magnetic powder in a magnetic coating film by a magnetic field generated by the solenoid coil. It is characterized in that it has a bent portion and is wound so that the generated magnetic field direction is substantially the same direction in the running region of the magnetic recording medium.

At this time, the solenoid coil may have a shape having a plurality of bent portions, and the bending degree of the plurality of bent portions may be gradually increased along the traveling direction of the magnetic recording medium.

The magnetic recording medium to which the present invention is applied is a so-called coating type magnetic recording medium in which a magnetic coating film is formed as a magnetic layer by coating a magnetic coating on the surface of a non-magnetic support. To be In the above-mentioned coating type magnetic recording medium, conventionally known magnetic powders, resin binders and the like constituting the non-magnetic support and the magnetic coating film can be used without any limitation.

For example, as magnetic powder, γ-Fe ₂ O
₃ , Fe ₃ O ₄ , γ-Fe ₂ O ₃ and Fe ₃ O ₄ beltride compound, Co-containing γ-Fe ₂ O ₃ , Co-containing F
γ-Fe ₂ O ₃ and Fe ₃ O ₄ containing e ₃ O ₄ and Co
And a beltride compound, an oxide containing one or more metal elements in CrO ₂ , such as Te, Sb, Fe and Bi, a metal such as Fe, Co and Ni, and Fe.
-Co, Fe-Ni, Fe-Co-Ni, Fe-Co-
B, Fe-Co-Cr-B, Mn-Bi, Mn-Al,
Examples thereof include alloys such as Fe-Co-V and acicular fine particles such as iron nitride.

Examples of the non-magnetic support include polymer supports made of polymer materials such as polyesters, polyolefins, celluloses, vinyl resins, polyimides and polycarbonates. To be

In addition to the above magnetic powder, a resin binder, a dispersant as an additive, an abrasive, an antistatic agent, an anticorrosive agent, etc. may be added to the magnetic paint.

Further, in the present invention, it is only provided that the undried magnetic coating film changes the traveling direction inside the solenoid coil by the guide roll from the initial traveling direction, and the winding material of the solenoid coil is made. The number of windings is not limited at all.

[0018]

In the method of manufacturing the magnetic recording medium of the present invention,
In a method of manufacturing a magnetic recording medium in which a magnetic recording medium is run in a solenoid coil to orient magnetic powder in a magnetic coating film, the solenoid coil has a bent portion, and the magnetic field direction generated by the solenoid coil is Since the traveling directions of the magnetic recording medium are substantially the same, a deviation occurs between the traveling direction of the magnetic recording medium and the magnetic field direction, and a magnetic field is obliquely applied to the magnetic recording medium at an angle corresponding to this deviation, The magnetic powder in the magnetic coating film is oriented obliquely.

Further, the present invention is a magnetic recording medium manufacturing apparatus which has a solenoid coil to which an electric current is supplied and orients magnetic powder in a magnetic coating film by a magnetic field generated by the solenoid coil. Since it has a bent portion and is wound so that the generated magnetic field direction is substantially the same direction in the traveling region of the magnetic recording medium,
A deviation occurs between the running direction of the magnetic recording medium and the magnetic field direction, and the magnetic field is obliquely applied to the magnetic recording medium at an angle corresponding to this deviation, and the magnetic powder in the magnetic coating film is oriented obliquely.

[0020]

EXAMPLES Hereinafter, specific examples of the present invention will be described, but it goes without saying that the present invention is not limited to these examples.

First, a magnetic recording medium manufacturing apparatus to which the present invention is applied will be described with reference to the drawings. As shown in FIG. 1, the magnetic recording medium manufacturing apparatus of this embodiment has a plurality of windings in which a coil extends along the running direction of an elongated magnetic recording medium 2 indicated by an arrow a in the figure. The solenoid coil 1 is provided. The solenoid coil 1 is sized to allow the magnetic recording medium 2 to run therein, and the orientation of magnetic powder in a magnetic coating film (not shown) while the magnetic recording medium 2 runs in the solenoid coil 1 Has been made long enough to be completed.

Further, as shown in FIG. 2, a DC power source 5 for supplying a DC power source to the solenoid coil 1 is connected to both ends of the solenoid coil 1. Therefore, when a current of a predetermined magnitude is supplied to the solenoid coil 1, a magnetic field H ₁ is generated from the solenoid coil 1 in the central axis direction indicated by D in the figure along the traveling direction of the magnetic recording medium 2, for example. To do.

On the other hand, the traveling direction of the magnetic recording medium 2 indicated by an arrow a in the figure is changed by the guide roll 3 at a midway portion, and the solenoid coil 1 is formed along this traveling direction.

Therefore, as shown in FIG. 2, the magnetic recording medium 2a first runs inside thereof in a state orthogonal to the coil winding direction of the solenoid coil 1a, but the running direction is changed by the guide roll 3. After that, the magnetic recording medium 2b runs inside the solenoid coil 1b in an inclined state with respect to the coil winding direction. That is, as shown in FIG. 3, in the magnetic recording medium running area indicated by l ₁ in the drawing, the magnetic recording medium 2a
The traveling direction indicated by the arrow a in the figure is parallel to the generation direction of the magnetic field H ₁ generated by a solenoid coil (not shown) indicated by D in the figure, and the magnetic field is applied to the magnetic recording medium 2a in the longitudinal direction. become. Also in the magnetic recording medium running area indicated by l ₂ in the figure, the solenoid coils 1a and 1b have the same coil winding direction as shown in FIG. 2, and therefore the solenoid not shown in FIG. 3 does not exist. The direction of generation of the magnetic field H ₁ generated by the coil is the direction indicated by the arrow D in the drawing, and there is a deviation of the angle θ from the running direction indicated by the arrow a in the drawing of the magnetic recording medium 2b, and in the running region l ₂ . An oblique magnetic field with an angle θ is applied to the magnetic recording medium 2b.

The angle θ can be freely designed by changing the tape running direction a, and the magnitude of the magnetic field in the oblique direction can be controlled by changing the magnitude of the current. θ
Is practically -90 ° <θ <90 ° with respect to the D direction.
Is preferred.

Further, the magnetic recording medium manufacturing apparatus of this embodiment may have a structure in which the solenoid coil 1 is provided with a plurality of bent portions as shown in FIG. That is, as shown in FIG. 5, the magnetic tape 2 is changed in traveling direction by the first guide roll 3 and then changed in traveling direction by the second guide roll 6. Therefore, as shown in FIG. 6, in the magnetic recording medium traveling area indicated by l ₁ in the figure, the magnetic recording medium 2a is generated by the traveling direction indicated by the arrow a in the figure and the solenoid coil (not shown) indicated by D in the figure. The magnetic fields H ₁ are generated in parallel directions, and the magnetic field is applied to the magnetic recording medium 2a in the longitudinal direction. Also, in the figure, l ₂ , l ₃
Even in the magnetic recording medium running area indicated by, since the coil winding directions of the solenoid coils 1a and 1b are the same as shown in FIG. 5, the magnetic field H generated by the solenoid coil (not shown) as shown in FIG. The direction of occurrence of ₁ is the direction indicated by the arrow D in the figure, and in the running area l ₂ , there is a deviation of the angle θ _{1 from} the running direction of the magnetic recording medium 2b indicated by the arrow a in the drawing, and the running area l ₃ In the above, the magnetic recording medium 2c has a deviation of an angle θ _{2 from} the running direction indicated by the arrow a in the figure. Therefore, the angle theta ₁ to the magnetic recording medium 2b in the running region l _2, oblique magnetic field angle theta ₂ is to be applied to the magnetic recording medium 2c in the running region l _3.

[0027] Although the two places bent portion in the present embodiment, may be provided more bends, increasing sequentially θ, 0 <θ ₁ <diagonally by a · · · <theta _n The orientation will proceed. The magnitude of the magnetic field in the diagonal direction can be controlled by changing the magnitude of the current, and the range of θ is
It is needless to say that the value may be expanded to the upper side because it is a value with respect to the magnetic field generation direction.

After that, if drying is carried out in a series of steps, a magnetic recording medium in an oblique orientation can be obtained. Of course, you may dry in a magnetic field.

Next, a magnetic recording medium was actually manufactured using the magnetic recording medium manufacturing apparatus of this embodiment.

Example 1 <Composition of magnetic paint> Fe acicular magnetic powder (coercive force 123 kA / m) 100 parts by weight binder vinyl chloride resin 10 parts by weight polyurethane resin 10 parts by weight carbon 3 parts by weight alumina 6 parts by weight solvent 250 Parts by weight methyl ethyl ketone 130 parts by weight toluene 70 parts by weight cyclohexanone 50 parts by weight

The above composition was used as a basic composition, mixed for 48 hours in a ball mill, and passed through a filter to obtain a magnetic paint. The magnetic paint was taken out, 4 parts by weight of a curing agent (trade name Coronate L) was further added, and the mixture was stirred for 30 minutes.
This magnetic paint was applied onto a polyethylene terephthalate base having a thickness of 7 μm by a roll coater so that the thickness after drying was 3 μm.
The coating was applied so as to obtain a magnetic recording medium manufacturing apparatus having a single bent portion of the solenoid coil of this embodiment shown in FIG. A 4 kGauss magnetic field was applied with a solenoid coil. The difference between the tape running direction and the magnetic field generation direction at this time is an angle θ = 45.
It was °. This was calendered and cured, and then a back coat layer was formed and cut into a predetermined width to prepare a sample tape.

Example 2 Next, the oblique orientation was performed using the magnetic recording medium manufacturing apparatus shown in FIG. 4 in which the bent portion of the solenoid coil of this example is two. As the alignment condition, a magnetic field of 4 kGaus
s, the deviation between the tape running direction and the magnetic field generation direction is an angle θ
_The guide rolls were arranged so that ₁ = 30 ° and the angle θ ₂ = 45 °. Then, a sample tape was produced by the same method as in Example 1.

Comparative Example 1 Next, by a magnetic recording medium manufacturing apparatus using a solenoid coil having no bent portion, 4 kGauss in the longitudinal direction.
After applying the magnetic field of 1., a sample tape was produced by the same method as in Example 1 except for the above.

The magnetic characteristics of each sample tape (Example 1, Example 2, Comparative Example 1) produced as described above were measured. The results are shown in Table 1.

[0035]

[Table 1]

As can be seen from Table 1, Rs in the longitudinal direction
Is decreased and Rs in the vertical direction is increased, so that the obliquely oriented sample tapes (Examples 1 and 2) are obliquely oriented as compared with the sample tapes having only the longitudinal orientation (Comparative Example 1). Was confirmed. Further, it can be seen that Example 2 is further oriented as compared with Example 1. Therefore, it was found that the magnetic powder in the magnetic coating film of the magnetic recording medium was obliquely oriented by the magnetic recording medium manufacturing apparatus of this example.

[0037]

As is apparent from the above description, in the method of manufacturing a magnetic recording medium of the present invention, the magnetic recording medium is run in the solenoid coil to orient the magnetic powder in the magnetic coating film. In the method of manufacturing a medium, since the solenoid coil has a bent portion and the magnetic field direction generated by the solenoid coil is substantially the same in the traveling area of the magnetic recording medium, the traveling direction of the magnetic recording medium and the magnetic field direction are There is a gap between them, and a magnetic field is applied obliquely to the magnetic recording medium with an angle corresponding to this gap, and the magnetic powder in the magnetic coating film can be oriented obliquely, thus providing a good quality magnetic recording medium. It is possible to manufacture
It can be carried out inexpensively and easily.

Further, the present invention is a magnetic recording medium manufacturing apparatus which has a solenoid coil to which an electric current is supplied and orients magnetic powder in a magnetic coating film by a magnetic field generated by the solenoid coil. Since it has a bent portion and is wound so that the generated magnetic field direction is substantially the same direction in the traveling region of the magnetic recording medium,
A deviation occurs between the running direction and the magnetic field direction of the magnetic recording medium, and a magnetic field is obliquely applied to the magnetic recording medium at an angle corresponding to this deviation, and the magnetic powder in the magnetic coating film may be oriented obliquely. Therefore, it is possible to manufacture a magnetic recording medium of good quality, and it is possible to carry out the manufacturing at low cost and easily. Target

Further, in the present invention, the solenoid coil is formed to have a plurality of bent portions, and the bending degree of the plurality of bent portions of the solenoid coil is gradually increased along the running direction of the magnetic recording medium. Therefore, the magnetic powder in the magnetic coating film of the magnetic recording medium is not forcibly oriented and can be oriented obliquely without disturbing, and the orientation angle can be freely determined.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a magnetic recording medium manufacturing apparatus to which the present invention is applied.

FIG. 2 is a schematic diagram showing an example of a magnetic recording medium manufacturing apparatus to which the present invention is applied.

FIG. 3 is a schematic diagram showing a tape running direction and a magnetic field generation direction of an example of a magnetic recording medium manufacturing apparatus to which the present invention is applied.

FIG. 4 is a perspective view showing an example of a magnetic recording medium manufacturing apparatus to which the present invention is applied.

FIG. 5 is a schematic diagram showing an example of a magnetic recording medium manufacturing apparatus to which the present invention is applied.

FIG. 6 is a schematic view showing a tape running direction and a magnetic field generation direction of an example of a magnetic recording medium manufacturing apparatus to which the present invention is applied.

[Explanation of Codes] 1,1a, 1b ... Solenoid coil 2, 2a, 2b, 2c Magnetic recording medium 3, 6 ... Guide roll 5 ...・ DC power supply

Claims (6)

[Claims] 1. A method of manufacturing a magnetic recording medium in which a magnetic recording medium is run in a solenoid coil to orient magnetic powder in a magnetic coating film, wherein the solenoid coil has a bent portion, and A method of manufacturing a magnetic recording medium, wherein the generated magnetic field directions are substantially the same in the running area of the magnetic recording medium. 2. The method of manufacturing a magnetic recording medium according to claim 1, wherein the solenoid coil has a plurality of bent portions. 3. The method of manufacturing a magnetic recording medium according to claim 2, wherein the bending degree of the plurality of bent portions of the solenoid coil is gradually increased along the traveling direction of the magnetic recording medium. 4. A magnetic recording medium manufacturing apparatus having a solenoid coil to which an electric current is supplied, wherein the magnetic powder generated in the magnetic coating film is oriented by a magnetic field generated by the solenoid coil. A magnetic recording medium manufacturing apparatus, wherein the magnetic recording medium is wound so that the generated magnetic field direction is substantially the same in the running region of the magnetic recording medium. 5. The apparatus for manufacturing a magnetic recording medium according to claim 4, wherein the solenoid coil has a plurality of bent portions. 6. The magnetic recording medium manufacturing apparatus according to claim 5, wherein the bending degree of the plurality of bent portions of the solenoid coil is gradually increased along the traveling direction of the magnetic recording medium.