JPH0312822A - Method for cutting magnetic recording medium - Google Patents

Abstract

PURPOSE:To suppress the generation of a crack of a ferromagnetic metallic film near a cut surface by making the peripheral velocity of the cutting edge of a cutter slightly faster than the travel velocity of a magnetic recording medium, and cutting the magnetic recording medium while stretching it in the travel direction with specific tension. CONSTITUTION:For cutting the magnetic recording medium 3 by the cutter in a prescribed width, the ratio v1/v2 of the peripheral velocity v1 of the cutting edges 4-7 and 8-11 in the cutter and the travel velocity v2 of the magnetic recording medium 3 is set to be 100-106%, and the cutting tension of the magnetic recording medium 3 in the travel direction is set to be less than 10g/mm so as to attain cutting. Thus, distortion for the magnetic recording medium 3 can be kept to a minimum so as to attain cutting and the generation of cracks in the ferromagnetic metallic thin film nearby part of cutting surface can be reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for cutting a magnetic recording medium, which is formed by forming a ferromagnetic metal thin film on a non-magnetic support, into a predetermined width. It is.

[Summary of the invention]

In the present invention, when cutting a magnetic recording medium formed by forming a ferromagnetic metal thin film on a non-magnetic support into a predetermined width using a cutting machine, the circumferential speed of the cutting blade of the cutting machine is set slightly higher than the running speed of the magnetic recording medium. This method attempts to suppress cranking of the ferromagnetic metal thin film in the vicinity of the cutting surface that occurs during °C1 cutting by increasing the speed and cutting the magnetic recording medium while pulling it with a predetermined tension in the running direction of the magnetic recording medium. It is.

[Conventional technology]

Conventionally, magnetic recording media have been produced by dispersing powder materials such as oxide magnetic powder or alloy magnetic powder on a non-magnetic support in an organic binder such as vinyl chloride-vinyl acetate copolymer, polyester resin, or polyurethane resin. Painted magnetic recording media, which are manufactured by applying and drying magnetic paint, are widely used.

On the other hand, with the increasing demand for high-density magnetic recording, metal magnetic materials such as Co-Ni alloy, Co-Cr alloy, and Co-○ are being used to form vacuum thin films using vacuum evaporation, sputtering, and ion-blating methods. The film was directly deposited on a non-magnetic support such as a polyester film or a polyimide film by a method or the like. A so-called metal magnetic thin film type magnetic recording medium has been proposed and is attracting attention. This metal magnetic thin film type magnetic recording medium not only has excellent coercive force and squareness ratio, but also has extremely small thickness loss during recording demagnetization and reproduction because the thickness of the magnetic layer can be made extremely thin.
Since there is no need to mix a non-magnetic binder into the magnetic layer, the packing density of the magnetic material can be increased, etc.
It has many advantages.

To produce a metal magnetic thin film type magnetic recording medium, first,
A wide non-magnetic support is caused to run from the unwinding roll to the winding roll of a vacuum evaporation apparatus through a running system consisting of an unwinding roll, a winding roll, and a cooling can disposed in the middle of these rolls.

Then, when the non-magnetic support moves along the circumferential surface of the cooling can, a ferromagnetic metal material is deposited from the vapor deposition source to form a ferromagnetic metal thin film on the non-magnetic support. Then, each magnetic tape is cut into a predetermined width using a cutting machine having a plurality of cutting blades.

[Problem to be solved by the invention]

However, in a magnetic tape having this type of ferromagnetic metal thin film as its magnetic layer, cranks are likely to occur in the ferromagnetic metal thin film in the vicinity of the cutting surface during cutting, and in particularly severe cases, cranks may extend to the recording track area. This results in the inconvenience that the original recording track section becomes effectively narrow, making it impossible to write or reproduce a desired information recording signal. Furthermore, there is a risk that the magnetic properties may deteriorate due to the influence of rust from the cut surface. Further, even if the crank does not extend to the recording track section, the surrounding area may be affected by distortion due to the influence of the crack, and the reciprocating output waveform may be disturbed.

Therefore, the present invention was proposed in response to the conventional situation, and suppresses the cranking of the ferromagnetic metal thin film in the vicinity of the cutting surface that occurs during cutting, secures an effective recording track portion, and prevents corrosion. It is an object of the present invention to provide a method for cutting a magnetic recording medium with excellent reliability and magnetic properties, which is less affected by such factors.

[Failure to solve the problem]

The present invention has been proposed to achieve the above object, and when cutting a magnetic recording medium formed by forming a ferromagnetic metal thin film on a non-magnetic support into a predetermined width using a cutting machine, The ratio v1/v2 of the circumferential speed V1 of the cutting blade of the cutting machine to the running speed v2 of the magnetic recording medium is 100 to 106%, and the cutting tension in the running direction of the magnetic recording medium is 10.
It is characterized in that it is cut to a size of g/mm or less.

[Operation] In order to cut a magnetic recording medium with a cutting machine, the ratio v of the circumferential speed v of the cutting blade of the cutting machine and the running speed V2 of the magnetic recording medium is determined.
1/v2 (hereinafter referred to as slip ratio) is important,
In the present invention, this slip rate is 100 to 106%.
The cutting is performed by setting the circumferential speed of the cutting blade slightly higher than the running speed of the magnetic recording medium. If you make the cut in this way,
The occurrence of scratches in the ferromagnetic metal thin film near the cutting surface is reduced.

In addition, since the magnetic recording medium is cut with a predetermined cutting tension in the running direction of the magnetic recording medium, it is possible to cut the magnetic recording medium while minimizing distortion to the magnetic recording medium. The occurrence of cranking in the ferromagnetic metal thin film in the vicinity is further reduced.

〔Example〕

Hereinafter, a specific example of a method for cutting a magnetic recording medium to which the present invention is applied will be described.

First, a wide magnetic recording medium (3) is produced by forming a ferromagnetic metal thin film (2) on a nonmagnetic support (1).

To form the ferromagnetic metal thin film (2), a non-magnetic support (
1) is passed from the unwinding roll to the winding furnace roll in a running system consisting of an unwinding roll, a winding roll, and a cooling can disposed in the middle of these rolls of a vacuum evaporation apparatus (not shown). and run it. Then, when the non-magnetic support (1) runs along the circumferential surface of the cooling can, a ferromagnetic metal material is deposited from the vapor deposition source.
) A ferromagnetic metal thin film (2) is formed on top of the ferromagnetic metal thin film (2).

The material of the non-magnetic support (1) and the ferromagnetic metal material used here are not limited in any way, and any conventionally known materials can be used.

To illustrate, as the material of the non-magnetic support (1),
Examples of polymer materials include polyesters, polyolefins, cellulose derivatives, vinyl resins, polyimides, polyamides, polycarbonates, and the like.

On the other hand, ferromagnetic metal materials include Fe, Co, and Ni.

Fe-Co, Co-Ni, Fe-Co-NiFe-Cu
Co-Cu, Co-Au, C.

PL, Mn-B1. Mn-Affi, Fe-C
rCo-Cr, Ni-Cr, Fe-Co-Cr
Examples include Co-Ni-Cr. These may be a single layer film or a multilayer film.

Furthermore, a nonmagnetic support (1) and a ferromagnetic metal thin film (2)
Improved adhesion between thin films, or in the case of multilayer films, between each thin film.
In addition, a base film or an intermediate film may be provided to control coercive force or the like.

The method for depositing the ferromagnetic metal material is not limited to the vacuum evaporation method as described above, but also the ion blating method in which the ferromagnetic metal material is evaporated in an electric discharge, or in an atmosphere mainly composed of argon. A sputtering method in which atoms on the target surface are hit with argon ions generated by glow discharge can also be applied.

Note that a lubricant layer may be formed on the ferromagnetic metal thin film (2) as necessary, or a back coat layer may be formed on the surface opposite to the ferromagnetic metal thin film (2). You may also do so. In this case, as the lubricant contained in the lubricant layer and the nonmagnetic pigment and resin binder contained in the rough coat layer, any conventionally known lubricant can be used.

Next, the magnetic recording medium (3) on which the ferromagnetic metal thin film (2) is formed as a magnetic layer is cut into a predetermined width using the cutting machine shown in FIGS. 1 and 2.

For example, as shown in FIGS. 1 and 2, the cutting machine has first cutting blades (4), (5), (6), (7) arranged side by side at predetermined cutting width intervals. and these first cutting blades (4), (5), (6),
Second cutting blades (8), (9), (10), which are arranged opposite to (7) and similarly arranged at cutting width intervals,
It consists of (11).

The first cutting blade (4), (5), (6),
(7) is formed into a substantially disk shape with a slightly conical shape, for example, from a steel material commonly used as a cutting blade,
One side (4a), (5a), (6a),
The outer peripheral edge of (7a) is the cutting edge. In addition, the first cutting blades (4), (5), (6) and (7) have a cylindrical spacer (12 ).

(13) and (14) are arranged in parallel in the axial direction at cutting width intervals, respectively, and the mounting is fixed. Therefore, the first cutting blades (4), (5), (6)
, (7) is adapted to physically rotate with the rotation axis. In addition, the first cutting blades (4), (5),
The peripheral speed V1 in (6) and (7) can be freely changed by controlling a motor or the like.

On the other hand, the second cutting blades (8), (9), (10)
, (11) are made into cylinders with different diameters by step-processing a part of the cylinder whose length is the same as the cutting width, and the side surface (8a), (9a) with the larger diameter
The outer peripheral edges of (10a) and (lla) serve as cutting edges. In addition, the outer peripheral surface (8b), (9
b), (10b), and (llb) are contact surfaces when cutting the magnetic recording medium (3). These second cutting blades (8), (9), (10), and (11) each contact in the axial direction a rotating shaft (not shown) that also rotates using a motor or the like as a drive source. The installation is fixed by arranging them in parallel. therefore,
These second cutting blades (8), (9), (10),
(11) is designed to rotate integrally with the rotation shaft like the previous one. Note that this second cutting blade (8
).

Similarly, the circumferential speeds of (9), (10), and (11) are
It can be changed freely by controlling a motor, etc.

These first cutting blades (4), (5), (6)
), (7) and the second cutting blade (8), (9), (1
0), (11) are arranged facing each other with a slight overship in the radial direction, and the cutting blades (4), (5),
Sides (4a) and (5a) of (6) and (7)
, (6a), (7a) and the second cutting blade (8),
Side (8a) of (9), (10), (11)
.

(9a), (10a), and (lla) are in contact with each other. That is, the side surface (4a) of the first cutting blade (4) and the side surface (8) of the second cutting blade (8)
a), the side surface (5a) of the first cutting blade (5), the side surface (9a) of the second cutting blade (9), the side surface (9a) of the first cutting blade (6);
6a) and the side surface (10a) of the second cutting blade (10), and the side surface (7a) of the first cutting blade (7) and the second cutting blade (11).
) are in contact with the side surfaces (lla), respectively, overlapping in the radial direction. Therefore, these first cutting blades (4), (5), (6), (7) and second cutting blades (8), (9), (10), (11)
) are rotated synchronously in the direction of arrow C in FIG. 1, these first cutting blades (4), (5),
(6), (7) and the second cutting blade (8), (9)
.

(10), (11) The magnetic recording medium (3) running between the first cutting blades (4), (5), (6)
, (7) cutting edge and second cutting blade (8) , (9)
, (10) and (1]) are used to cut to a predetermined cutting width.

Note that the first cutting blades (4), (5), (6)
), (7) and the second cutting blade (8), (9)
, (10), and (11). If the degree of overlap with these first cutting blades (4) and (11) is too large, there is a risk that the magnetic recording medium (3) will be deformed.
5), (6), (7) and the second cutting blade (8)
, (9), (10), and (11), it is preferable that the angle formed by the tangents (so-called cutting angle) θ is 10° or less. More preferably 10° to 5°
It is good to say.

Note that the above-mentioned cutting machine is not limited to this example,
Any conventionally known materials used in this type of field can be used.

In order to cut a wide magnetic recording medium (3) using the cutting machine described above, the magnetic recording medium (3) is cut with the first cutting blade (
4), (5), (6), (7) and the second cutting blades (8), (9), (10), (11), run in the direction of arrow C in FIG.

At this time, in the magnetic recording medium (3), the ferromagnetic metal thin film (2) is connected to the second cutting blade (8), (9),
(10)1 It is desirable to run the vehicle facing towards the (11) side. In this way, the ferromagnetic metal thin film (2) can be
The outer circumferential surface of the larger diameter cutting blade (8), (9), (10), (11) (8bL (9b), (10b),
Since it is cut in a controlled manner by (llb), the generation of cranks can be further suppressed. In addition, -J2 first cutting blade (4), (5), (6), (7) and second cutting blade (8), (9), (10), (11)
The magnetic recording medium (3) is rotated at a circumferential speed v1 in the running direction of the magnetic recording medium (arrows a and b directions in the figure) at a circumferential speed v1, and the magnetic recording medium (3) is run at a running speed v2 to achieve a slip ratio of 100.
~106%. The reason why the slip rate is regulated in this way is that if the slip rate exceeds the above range, extra stress will be applied to the magnetic recording medium (3) and the cut surface will deform.On the other hand, if it falls below the above range, it will suddenly deform. ferromagnetic metal thin film (
This is because 2) there will be more cracks. In addition, at this time, the cutting tension in the running direction of the magnetic recording medium was further increased to 10 g/m.
m or less. That is, the magnetic recording medium (3) is pulled in the running direction of the magnetic recording medium with a tension of 10 g/mm or less.

The cutting tension is set to 10 g/+nm or less for the relevant cutting]
2. This is because when the tension exceeds 10 g/mm, the occurrence of cracks increases rapidly. Regarding the lower limit of cutting tension,
If the cutting tension becomes extremely small, the magnetic recording medium (3) will not be able to run normally, so it should be at least 2.0.
g/mm is required.

As a result, the magnetic recording medium (3) has the first cutting blades (4), (5), (6), (7) and the second cutting blades (8), (9), (10), ( 11), the material is cut to a desired cutting width.

At this time, the first cutting blades (4), (5),
(6), (7) and the second cutting blade (8), (9)
, (10), and (11), the peripheral speed ■1 is slightly faster than the running speed v2 of the magnetic recording medium (3), and the magnetic recording medium (3) is pulled with a predetermined tension in the running direction of the magnetic recording medium. Therefore, the influence of distortion on the magnetic recording medium (3) during cutting can be minimized.

Therefore, the number of cranks generated in the ferromagnetic metal thin film near the cut surface of the magnetic recording medium (3) is reduced.

Here, the present inventors actually cut a magnetic tape under the following conditions.

First, a polyethylene terecrate film with a thickness of 10 μm is used as the non-magnetic support (1), and this is run through a vacuum evaporation device to deposit a Co-Ni alloy (Co-Ni alloy) in an oxygen atmosphere.
:N1=80 :20) was deposited to a film thickness of 0.15μ.
A ferromagnetic metal thin film (2) of m thickness was formed.

Next, the magnetic recording medium (3) was cut into a width of 8 mm using the cutting machine described above.

When cutting the magnetic recording medium (3), the slip rate and
Cutting was carried out by varying the cutting tension in the running direction of the magnetic recording medium.

In addition, the first cutting blades (4), (5),
(6), (7) and the second cutting blade (8), (9)
), (10), and (11), the overlap distance 11 was set to 0.25 mm.

Then, the range of occurrence of crank cracks in the ferromagnetic metal thin film (2) near the cut surface of the cut magnetic tape was measured. The results are shown in FIG. Note that the line d in FIG. 3 indicates a cutting tension of 15 g/mm.

Line e has a cutting tension of 10 g/mm, line f has a cutting tension of 5.0 g.
/mm, and the line g is the value when the cutting tension is 2.5 g and 7 mm.

For example, with 8M tape, the occurrence of cracks is 10 mm from the cut surface.
If it extends to μm or more, write it down! 2+・Distortion occurs even in the rack part, so the crack.

It is desirable that the range in which this occurs is 10 μrn or less, which does not pose a practical problem. Therefore, in order to suppress the generation of cracks to 10 μm or less from the cut surface, the slip ratio should be set to 100 to 106%, and the cutting tension in the running direction of the magnetic recording medium should be set to 10 g/mm or less, as shown in FIG.

If the cutting is performed under such conditions, the occurrence of cracks can be minimized and the effective range of the recording track portion can be secured. Furthermore, deterioration of magnetic properties due to progress of rust from the cut surface is also suppressed, and fluctuations in the reproduced output waveform are also reduced.

〔Effect of the invention〕

As is clear from the above description, in the method of the present invention, when cutting a magnetic recording medium in which a ferromagnetic metal thin film is formed on a non-magnetic support into a predetermined width, the circumferential speed of the cutting blade is adjusted magnetically. Since cutting is performed at a speed slightly higher than the running speed of the recording medium and by pulling the magnetic recording medium with a predetermined tension in the running direction of the magnetic recording medium, there is no effect of distortion on the magnetic recording medium during cutting. The ferromagnetic metal thin film can be cut to a minimum, and cracks in the ferromagnetic metal thin film near the cut surface that occur during cutting can be minimized.

Therefore, it is possible to secure an effective range of the recording track section, suppress fluctuations in the reproduced output waveform, and have excellent reliability and magnetic properties that are not affected by rust from the cut surface. It becomes possible to provide magnetic recording media.

G 4.5, 6.7...first cutting blade

Claims (1)

[Claims] When cutting a magnetic recording medium formed by forming a ferromagnetic metal thin film on a non-magnetic support into a predetermined width using a cutting machine, The ratio v_1/v_2 of the running speed v_2 is 100 to 106%, and the cutting tension in the running direction of the magnetic recording medium is 1.
A method for cutting a magnetic recording medium, the method comprising cutting a magnetic recording medium to a thickness of 0 g/mm or less.