JPH05298691A - Method for orienting perpendicularly magnetic recording medium and device therefor - Google Patents

Abstract

PURPOSE:To orient magnetic powder contained in a magnetic coating film to a magnetic coating film surface nearly perpendicularly with simple constitution. CONSTITUTION:The different polarities of magnets 4, 5 arranged to face oppositely are faced on the transfer path 3 of a magnetic recording medium 2 coating the magnetic coating film 22 containing the magnetic powder 21 on a nonmagnetic supporting body 20, and magnetic material 6, 7 are provided around respective magnets 4, 5. By magnetic path formed with the magnetic material 6, 7, magnetic field with different magnetism is prevented from occurring by the coercive force Hc or above of the magnetic powder except between the magnets 4, 5 arranged to face oppositely on the magnetic path formed by the magnetic material 6, 7, and magnetic field nearly perpendicular to on the magnetic coated film surface is impressed only between the magnets 4, 5 arranged to face oppositely and the magnetic powder 21 contained in the magnetic coated film 22 is oriented to the magnetic coating film surface nearly perpendicularly.

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 vertical alignment method and a magnetic recording medium vertical alignment apparatus for aligning magnetic powder contained in a magnetic coating film substantially perpendicularly to the surface of the magnetic coating film. ..

[0002]

2. Description of the Related Art In magnetic recording, there is a system using magnetization in the longitudinal direction of a magnetic recording medium. If this system is used to further improve the recording density, the demagnetizing field in the magnetic recording medium increases. Therefore, the recording density is limited, and the recording density cannot be improved so much.

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

[0004]

Therefore, according to such a perpendicular magnetic recording system, a magnetic recording medium in which magnetic powder contained in a magnetic coating film is oriented substantially perpendicular to the surface of the magnetic coating film is used. Is desirable.

For this reason, for example, a non-magnetic support is coated with a magnetic coating film containing magnetic powder on a conveyance path of a magnetic recording medium,
There is a method in which magnets arranged facing each other are made to face different polarities and magnetic particles are oriented between the magnets.However, even if the magnets are oriented substantially vertically between the magnets, a leakage magnetic field or a magnetic field near the magnets may be generated. Due to the reversal magnetic field etc., a magnetic field opposite to that between the magnets is created,
As a result, what is oriented substantially vertically collapses, and it is not possible to effectively orient substantially vertically.

The present invention has been made in view of the above points, and has a simple structure, in which magnetic powder contained in a magnetic coating film can be oriented substantially perpendicular to the surface of the magnetic coating film. An object of the present invention is to provide an orientation method and a magnetic recording medium vertical orientation device.

[0007]

In order to solve the above-mentioned problems, the method of perpendicularly orienting a magnetic recording medium according to the invention as defined in claim 1 is a magnetic recording medium comprising a non-magnetic support coated with a magnetic coating film containing magnetic powder. In the transport path of the recording medium, different polarities of the magnets facing each other are faced, magnetic materials are provided around the respective magnets, and the magnetic paths formed by the magnetic material A magnetic field having different magnetism is not generated except for the coercive force Hc of the magnetic powder except in the space, and a magnetic field substantially perpendicular to the magnetic coating surface is applied only between the magnets arranged facing each other.
The magnetic powder contained in the magnetic coating film is oriented substantially perpendicular to the surface of the magnetic coating film.

Further, the magnetic recording medium vertical aligning apparatus of the invention according to claim 2 is arranged so as to face the conveying path of the magnetic recording medium in which the magnetic coating film containing the magnetic powder is coated on the non-magnetic support. Different polarities of the magnets are faced to each other, magnetic materials are provided around the respective magnets, and the magnetic characteristics of the magnets have a residual magnetic flux density Br higher than the coercive force Hc of the magnetic powder,
The coercive force Hc is 5 KOe or more, the magnetic characteristics of the magnetic material are initial magnetic permeability μ = 4 KGauss or more and the saturation magnetic flux density Ms = 8 KGaus or more, and the following expressions are established as the shapes of the magnet and the magnetic material. It is characterized by doing.

A> B × Br / (Ms × 2) A: Magnetic path cross-sectional area formed of magnetic material B: Magnet cross-sectional area in the direction orthogonal to the magnetic field direction generated between the magnets. The magnetic recording medium vertical orientation device is characterized in that the width of the magnetic material in the magnetic recording medium transport direction is equal to or larger than the width of the magnet.

The magnetic recording medium applied in the present invention is a coating type magnetic recording medium. For example, one side of a long non-magnetic support is coated with a magnetic coating film containing magnetic powder. It is formed. As this non-magnetic support, for example, a known resin film is used, and the magnetic powder in the magnetic coating film coated on the non-magnetic support can be any conventionally known magnetic powder and is not limited in any way. ..

Further, according to the present invention, magnets arranged opposite to each other are opposed to each other in the conveying path of the magnetic recording medium, magnetic materials are provided around the respective magnets, and the magnetic paths are formed by the magnetic materials. Then, a magnetic field having different magnetism is prevented from occurring between the magnets arranged opposite to each other, which is equal to or larger than the coercive force Hc of the magnetic powder, and a magnetic field almost perpendicular to the magnetic coating surface is formed only between the magnets arranged opposite to each other. The magnetic powder contained in the magnetic coating film is oriented substantially perpendicular to the surface of the magnetic coating film.

As the magnet of the present invention, for example, an electromagnet or a permanent magnet can be used, and the magnetic characteristics of this magnet are that the residual magnetic flux density Br is higher than the coercive force Hc of the magnetic powder, and this coercive force Hc = 5 KOe or more. Is.

As the magnetic material, for example, a metal can be used, and the magnetic characteristics of this magnetic material are the initial permeability μ = 4 KGau.
ss or more and the saturation magnetic flux density Ms = 8KGauss or more.

The shapes of the magnet and the magnetic material according to the present invention are configured so that the following expression is established, and the shape is not particularly limited as long as this expression is established.

A> B × Br / (Ms × 2) A: Cross-sectional area of magnetic path formed of magnetic material B: Cross-sectional area of magnet in the direction perpendicular to the direction of the magnetic field generated between magnets. By specifying the shape of the material, magnetic fields such as leakage magnetic field and reversal magnetic field do not occur in the magnetic path formed by the magnetic material except between the magnets arranged facing each other. A magnetic field substantially perpendicular to the surface of the magnetic coating film is applied only during this period, and the magnetic powder contained in the magnetic coating film is oriented substantially perpendicular to the surface of the magnetic coating film.

Furthermore, the width of the magnetic path material in the magnetic recording medium transport direction is configured to be greater than or equal to the width of the magnet,
A magnetic field in the same direction as the magnetic field between the magnets facing each other is generated more widely so that a magnetic field substantially perpendicular to the magnetic coating surface is not suddenly applied only between the magnets facing each other.
The magnetic powder contained in the magnetic coating film is surely oriented substantially perpendicular to the surface of the magnetic coating film.

[0017]

According to the first aspect of the present invention, the different polarities of the magnets facing each other are faced to the conveying path of the magnetic recording medium,
A magnetic material is provided around each of these magnets to form a magnetic path, and the leakage magnetic field and the reversal magnetic field are significantly reduced in this magnetic path, and only a magnetic field component substantially perpendicular to the magnetic coating surface is applied. The magnetic powder contained in the magnetic coating film is oriented substantially perpendicular to the surface of the magnetic coating film.

According to a second aspect of the present invention, magnets arranged opposite to each other are made to face different polarities in the conveying path of the magnetic recording medium, and a magnetic material is provided around each of the magnets. By defining the magnetic characteristics of the magnetic material and specifying the shape of the magnet and the magnetic material, a magnetic path is formed around the magnet, and the leakage magnetic field and the reversal magnetic field are significantly reduced by this magnetic path. By applying only a magnetic field component substantially perpendicular to the coating film surface, the magnetic powder contained in the magnetic coating film is oriented substantially perpendicular to the magnetic magnetic coating film surface.

According to the third aspect of the invention, the width of the magnetic path material in the magnetic recording medium conveyance direction is set to be equal to or larger than the width of the magnets, so that a vertical magnetic field in the same direction as between the magnets is conveyed in the magnetic recording medium. The magnetic powder contained in the magnetic coating film can be made sure that the magnetic powder contained in the magnetic coating film surface is not suddenly applied to the magnetic coating film surface only between the magnets arranged facing each other. Oriented substantially perpendicular to.

[0020]

Embodiments of a magnetic recording medium vertical alignment method and a magnetic recording medium vertical alignment apparatus according to the present invention will be described below with reference to the drawings. 1 is a front view of a magnetic recording medium vertical alignment device, FIG. 2 is a plan view of a magnetic recording medium vertical alignment device, FIG. 3 is a right side view of a magnetic recording medium vertical alignment device, and FIG. 4 is a magnetic recording medium before vertical alignment. 5 is a cross-sectional view of the magnetic recording medium after vertical alignment, and FIG. 6 is a view showing a magnetic hysteresis loop.

In this magnetic recording medium vertical orientation device 1, magnets 4 and 5 are arranged to face the conveying path 3 of the magnetic recording medium 2, and the magnets 4 and 5 are long in the width direction of the conveying path 3. The plate is formed with a height H1, a width W1, and a depth D1. The magnets 4 and 5 are permanent magnets, and the S pole of the magnet 4 and the N pole of the magnet 5 face each other. Thus, the magnets 4 and 5 are arranged so as to face different polarities. There is. Magnetic materials 6 and 7 are provided around the respective magnets 4 and 5, and the magnets 4 and 5 are arranged in the concave portions 6a and 7a of the magnetic materials 6 and 7, respectively. The magnetic materials 6 and 7 are also the transport path
Is formed in a plate shape having a height H2, a width W2, and a depth D2.

As shown in FIG. 4, the magnetic recording medium 2 is a coating type magnetic recording medium, for example, a long non-magnetic support 2
The magnetic coating film 22 containing the magnetic powder 21 is applied to one surface of the magnetic recording medium 0, and the magnetic powder 21 is in a lying state in the magnetic recording medium 2 before vertical alignment. When this magnetic recording medium 2 is vertically oriented by the magnetic recording medium vertical orientation device 1, the magnetic powder 21 rises in a substantially vertical direction.

In the magnetic recording medium vertical orientation apparatus 1, the magnetic characteristics of the magnets 4 and 5 have a residual magnetic flux density Br higher than the coercive force Hc of the magnetic powder 21, and the coercive force Hc = 5 KOe or more. The magnetic properties of 6 and 7 are initial permeability μ = 4K
Gauss or higher, and saturation magnetic flux density Ms = 8 KGaus or higher.

The coercive force Hc, the residual magnetic flux density Br, the initial magnetic permeability μ and the saturation magnetic flux density Ms are defined as shown in the magnetic hysteresis loop of FIG.

That is, when a magnetic field is applied to a magnetic body that is not magnetized at all to increase its strength, the magnetic induction produced is shown in FIG.
It gradually increases through the shapes of A, B, C, and D. This is shown by an initial magnetization curve, and the slope at the rising is the initial magnetic permeability μ, which can be shown by the initial magnetic permeability μ = dB / dH and the magnetic field strength H → 0.

Under a sufficiently large magnetic field, the magnetic field strength I saturates to a constant value, so that the rate of change of the magnetic flux density B becomes a constant value dB / dH = μ0. The point where the strength I of the magnetic field is saturated and becomes a constant value is called the saturation magnetic flux density Ms.

Next, when the magnetic field is lowered, the magnetic flux density B changes along a path different from the previous one, and has a constant residual magnetic flux density Br when the magnetic field strength H = 0. In order to reduce the residual magnetism, B = 0 only when the magnetic field strength becomes Hc. This value of Hc is called a holding force.

The shapes of the magnets 4 and 5 and the magnetic materials 6 and 7 are set so that the following equation is established.

A> B × Br / (Ms × 2) A: Cross-sectional area of magnetic path formed of magnetic material B: Cross-sectional area of magnet in the direction perpendicular to the magnetic field generated between magnets. A magnetic path is formed around the magnets 4 and 5, and this is indicated by a magnetic path cross-sectional area A. By thus specifying the shapes of the magnets 4 and 5 and the magnetic materials 6 and 7, in the magnetic path formed by the magnetic materials 6 and 7, there is no leakage magnetic field except between the magnets 4 and 5 which are arranged facing each other. The magnetic powder 21 contained in the magnetic coating film 22 is prevented by applying a magnetic field almost perpendicular to the magnetic coating film surface only between the magnets 4 and 5 arranged so as to oppose each other so as not to generate a magnetic field such as a magnetic field. It is arranged to be oriented substantially perpendicular to the surface of the magnetic coating film.

The width C of the magnetic materials 6 and 7 in the magnetic recording medium transport direction is set to be larger than the width D of the magnets 4 and 5.

As described above, the width C of the magnetic path members 6, 7 in the magnetic recording medium transport direction is set to be equal to or larger than the width D of the magnets 4, 5 so that the magnets 4, 5 arranged to face each other. The magnetic field in the same direction as the magnetic field between the magnetic field and the magnetic field can be generated more widely, and the magnetic field substantially perpendicular to the magnetic coating film surface is prevented from being suddenly applied only between the magnets 4 and 5 arranged facing each other. As shown in, the magnetic powder 21 contained in the magnetic coating film 22 is surely oriented substantially perpendicular to the surface of the magnetic coating film.

Next, specific examples 1 to 8 of the present invention will be described.

[Table 1] shows Comparative Examples 1 to 5

[0033]

It shows in [Table 2].

[0034]

[Table 1]

[0035]

[Table 2] In the evaluation of Examples 1 to 8 and Comparative Examples 1 to 5, a tomographic photograph of the magnetic recording medium was taken with a transmission electron microscope to confirm the degree of vertical orientation of the magnetic powder. Also, the electromagnetic conversion characteristics at that time were evaluated using a modified deck of a commercially available 8 mm VTR. In addition,
Examples 6 to 8 and Comparative Example 5 were evaluated using a modified VHS commercial deck. These evaluation results

It shows in [Table 3].

[0036]

[Table 3] this

As is clear from Table 3, the magnetic powder is oriented substantially vertically in Examples 1 to 8, but the magnetic powder is not oriented vertically in Comparative Examples 1 to 5.

[0037]

As described above, according to the first aspect of the invention, different polarities of the magnets arranged to face each other are faced to the transport path of the magnetic recording medium, and the magnetic material is provided around each of the magnets. To form a magnetic path, which greatly reduces the leakage magnetic field and the reversal magnetic field, and applies only the magnetic field component that is almost perpendicular to the magnetic coating film surface. It has a simple structure because it can be oriented substantially perpendicular to the surface of the coating film.

According to a second aspect of the present invention, the magnets facing each other are provided with a magnetic material having different polarities in the conveying path of the magnetic recording medium, and a magnetic material is provided around each of the magnets. By defining the magnetic characteristics of the magnetic material and forming a magnetic path around the magnet with a magnet and a simple structure that specifies the shape of the magnetic material, the leakage magnetic field and the reversal magnetic field are significantly reduced by this magnetic path, Only a magnetic field component substantially perpendicular to the surface of the magnetic coating film is applied, whereby the magnetic powder contained in the magnetic coating film is oriented substantially perpendicular to the surface of the magnetic coating film.

According to the third aspect of the present invention, the width of the magnetic path material in the magnetic recording medium conveyance direction is set to be equal to or larger than the width of the magnets, so that the vertical magnetic field in the same direction as between the magnets is made wider and the magnets face each other. It is possible to prevent a magnetic field that is substantially perpendicular to the magnetic coating surface from being suddenly applied only between the magnets that are arranged in a line, and the magnetic powder contained in the magnetic coating film is sure to be substantially perpendicular to the magnetic coating surface. Orient to.

[Brief description of drawings]

FIG. 1 is a front view of a magnetic recording medium vertical alignment device.

FIG. 2 is a plan view of a magnetic recording medium vertical alignment device.

FIG. 3 is a right side view of a magnetic recording medium vertical alignment device.

FIG. 4 is a cross-sectional view of a magnetic recording medium before vertical alignment.

FIG. 5 is a cross-sectional view of a magnetic recording medium after vertical alignment.

FIG. 6 is a diagram showing a magnetic hysteresis loop.

[Explanation of symbols]

 1 Magnetic Recording Medium Vertical Alignment Device 2 Magnetic Recording Medium 3 Conveying Path 4,5 Magnets 6,7 Magnetic Material 20 Non-magnetic Support 21 Magnetic Powder 22 Magnetic Coating

Claims (3)

[Claims] 1. A magnetic recording medium coated with a magnetic coating containing magnetic powder on a non-magnetic support is made to face a conveying path of a magnetic recording medium with different polarities of magnets facing each other. A magnetic material is provided so that magnetic fields having different magnetism are not generated in the magnetic path formed by the magnetic material except between the opposed magnets, which are equal to or higher than the coercive force Hc of the magnetic powder. A magnetic recording medium vertical alignment method characterized in that a magnetic field substantially perpendicular to the magnetic coating film surface is applied only during the gap to orient the magnetic powder contained in the magnetic coating film substantially perpendicular to the magnetic coating film surface. .. 2. A magnetic recording medium coated with a magnetic coating containing magnetic powder on a non-magnetic support is made to face a conveying path of a magnetic recording medium with different polarities of magnets facing each other. A magnetic material is provided, and the magnetic characteristic of the magnet has a residual magnetic flux density Br higher than the coercive force Hc of the magnetic powder, and the coercive force Hc is 5 KOe or more, and the magnetic characteristic of the magnetic material is the initial permeability μ. = 4KGauss or more, saturation magnetic flux density Ms = 8KGauss or more, and the following equations are satisfied as the shapes of the magnet and the magnetic material. A> B × Br / (Ms × 2) A: Magnetic path cross-sectional area formed by magnetic material B: Magnet cross-sectional area in the direction orthogonal to the magnetic field direction generated between the magnets 3. A magnetic recording medium vertical alignment device according to claim 2, wherein the width of the magnetic material in the magnetic recording medium conveyance direction is equal to or larger than the width of the magnet.