JPS62134828A - Roller and method for orienting disk-shaped magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain high input and output and recording density by rotating rollers disposed with the same magnetic poles on both sides of plural magnetic polar line provided on the peripheral face in the transverse direction and curing a magnetic coating compd. on a base having the axis of rotation intersecting orthogonally therewith. CONSTITUTION:The roller 1 is formed by fitting wedge-shaped magnets 3 magnetized in the thickness direction to the circumference of a core 8 having a revolving shaft 7, by which the magnetic poles reverse from each other are formed between the adjacent magnetic polar lines. The base 5 consisting of a polyester is placed on a nonmagnetic horizontal turntable 9 and is rotated around a shaft 10. A magnetic coating compd. is blown from a nozzle 11 near the center of the base 5. The rollers 1 are provided under the table 9 and the shafts 7 and 9 are orthogonally disposed so that the two rollers 1 exist on one straight line with the center of the shaft 11 in-between. The peripheral faces of the rollers are held in proximity to the bottom surface of the table. The magnetic particles are iteratively erected, laid down, and reverse erected by the magnetic fields on the magnetic polar line 2 by which the magnetic particles are oriented in the concentrical circumferential direction around the central axis (a) of the base 5. These particles are fixed on curing. The high input and output are obtd. and the recording density is improved in the stage of shifting a head concentrically with the recording surface and making recording and reproducing.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a roller for orienting magnetic particles on the recording surface of a disk-shaped magnetic recording medium in a fixed direction, and an orienting method using the roller. .

[Conventional technology]

Disk-shaped magnetic recording media such as floppy disks have a disk-shaped base made of non-magnetic material.

The recording surface is created by applying magnetic paint and curing it.

Conventional methods for creating this recording surface can be roughly divided into so-called continuous methods and spinner methods.

The former is a method in which a long polyester film or the like is continuously coated with magnetic paint using a gravure method or the like, the magnetic paint is smoothed, dried, and then punched out into a circular shape. The latter is a method in which a pre-punched circular base is rotated horizontally around the center, while magnetic paint is sprayed near the center of the base, the magnetic paint is dispersed onto the base by centrifugal force, and then it is dried. It is.

[Problem that the invention seeks to solve]

In disc-shaped magnetic recording media such as frosopie disks, a recording method is used in which recording and reproduction are performed by moving a magnetic head concentrically on the recording surface. Therefore, the highest input/output can be obtained when the magnetic particles on the recording surface are oriented along the circumferential direction of the concentric circles in which the magnetic head moves.

However, on the record surface made by the former continuous method.

Since the undried magnetic paint is smoothed by stroking it in the longitudinal direction with a smoother, the magnetic particles are oriented in a certain direction at every location, and the oriented direction and the direction perpendicular to this are square. The ratio differs by around 10%. Therefore, in the above-described recording method, input and output vary depending on the position of the magnetic head.

Also, the recording surface made by the latter spinner method.

Since the magnetic paint is dispersed without contact by centrifugal force, the magnetic particles become non-oriented. Therefore, depending on the position of the magnetic head, there is almost no variation in input/output, but the input/output level obtained from the magnetic head is lower than that of a magnetic head oriented in two circumferential directions.

These inventions were made to solve the above-mentioned conventional problems, and when manufacturing magnetic recording media, an orientation roller and an orientation roller that can orient the magnetic particles in the magnetic paint in the direction in which the magnetic head moves. It is an object of the present invention to provide a method and thereby improve the recording density of a disk-shaped magnetic recording medium.

[Means to solve the problem]

The configurations of these inventions will be described below with reference to the reference numerals in FIGS. 1 to 3.

First, to explain the first invention regarding the orientation roller, a plurality of magnetic pole lines 2.2-=... are provided in the width direction of the circumferential surface of the roller 1. Identical magnetic poles of magnets 3.3-- are arranged on both sides of these magnetic pole lines 2.2--, thereby forming abutting magnetic poles on the separated polar lines 2.2--. Then, the magnetic poles of the adjacent magnetic pole lines 2.2- are alternately set as opposite magnetic poles.

Next, a second invention related to an orientation method will be explained. In this method, the roller 1 is used, and its center axis b is oriented in a direction perpendicular to the rotation center axis a of the base 5, and its circumference is Bring the surface close to the base 5. Magnetic paint is uniformly applied to the surface of the base 5 that will become the recording surface 4, and while the magnetic paint is uncured, the base 5 is rotated around the rotation center axis a, and the roller 1 is moved to the center of the base 5. axis,
Rotate around b. Next.

The above magnetic paint is cured.

[For production]

This is because, in the orientation roller according to the first invention, the abutting magnetic poles are formed on the magnetic pole lines 2.2- formed in the width direction of the circumferential surface of the roller 1.

As shown in FIG. 3, a magnetic field perpendicular to the circumferential surface of the roller 1 is formed above these magnetic pole lines 2, 2-. Since the adjacent magnetic pole lines 2, 2, . . . alternately have opposite magnetic poles, the direction of the magnetic field is opposite between the adjacent magnetic pole lines 2, 2.

The center axes of the rollers 1, b are the rotation center axes of the base 5.
The base 5 rotates its circumferential surface in a direction perpendicular to the base 5.
When the uncured magnetic paint applied to the base 5 passes close to the roller 1, it is affected by the magnetic field.

That is, when the recording surface is on the magnetic pole line 2 of the roller 1, the magnetic paint there.

It is erected by a magnetic field formed on the magnetic pole line 2. However, because roller 1 is also rotating.

The magnetic pole line 2 moves relative to the magnetic particle and the 9th order magnetic pole line 2
The magnetic particles are once tilted in a direction perpendicular to the ceramic wire 2.2. Next, it is erected on top of the tertiary magnetic pole line 2, this time in the opposite direction to the previous magnetic pole line 2.

By repeating this several times, all the magnetic particles come close to the roller 1 and are lined up in a direction perpendicular to the magnetic pole lines 2°2-.-. That is, it is oriented in the circumferential direction of a concentric circle around the rotation center axis a of the base 5. After that, when the magnetic paint is cured, this orientation state is fixed.

[Example] Next, an implementation project of the present invention and its preferred embodiment will be described with reference to nine drawings.

First, an embodiment of the orientation roller according to the first invention will be described. A wedge-shaped magnet 3.3- is fitted around a roller core 8 on which a rotating shaft 7.7 is fixed on the central axis.
A roller 1 is configured. The magnets 3.3 include rare earth magnets magnetized in the thickness direction, and are arranged in the longitudinal direction along the width direction of the roller 1.
They are arranged in the thickness direction along the circumferential direction of the roller. In this case, the magnetic poles of the magnets 3.3- adjacent in the thickness direction are arranged in opposite directions.

Due to this arrangement of the magnets 3.3-, the distance between the rows of magnets 3.3- along the width direction of the roller 1 is the magnetic pole line 2.2-.
Abutting magnetic poles are formed on these magnetic pole lines 2.2 so that adjacent magnetic poles 2.2 are opposite magnetic poles.

Note that when the width of the roller 1 is relatively narrow, a single elongated magnet 3 may be buried in place of the array of magnets 3, 3, . . . arranged in the width direction of the circumferential surface.

Next, a second embodiment of the invention using the roller 1 will be described. A base 5 made of polyester film or the like is placed on a horizontal rotary table 9 made of a non-magnetic material such as stainless steel or aluminum and rotated nine times. The rotary table 9 is rotated around its central axis a by a rotary shaft 10 of the table 9. The rotary table 9 is preferably as thin as possible.

The base 5 is coated with magnetic paint. This magnetic paint is 1
It is also possible to apply the coating in advance before placing it on the rotary table 9. However, the magnetic paint can be uniformly dispersed on the recording surface 4 of the base 5 by using the rotation by the one-turn table 9, and the magnetic particles can be easily oriented in the desired direction.

It is preferable to apply by the spinner method. In the illustrated embodiment, a spinner method is used in which a nozzle 11 is arranged near the center of the base 5, and magnetic paint is sprayed onto the base 5 and dispersed around the base 5 by centrifugal force.

Below the rotary table 9, the already mentioned roller 1.1 is arranged. The rollers 1, 1 are arranged such that the center axes s, b of the rotation shafts 7, 7 are orthogonal to the center axis a of the rotation shaft 10. In the illustrated case, the central axes of the two rollers 1.degree. 1 and b are arranged on the same straight line with the central axis a sandwiched therebetween. The circumferential surfaces of the rollers 1, 1 are preferably placed as close to the lower surface of the rotary table 9 as possible.

In this state, the roller 1°1 is rotated by the 9-rotation shaft 7.7. The relative speed between the circumferential surfaces of the rollers 1, 1 and the base 5 at this time is preferably as fast as possible. For this reason, in the exemplary embodiment shown in the two figures, the directions of rotation of the rotary table 9 and the rollers 1.1 are respectively selected so that they run in opposite directions.

The inventor of the present invention actually made a 5A inch floppy disk using the above method using a polyester film having a thickness of 75 μm. Further, as shown in FIG. 4, in the A section and the B section which are shifted by 90 degrees from each other on this floppy disk, the radial direction (Y direction) of the recording surface 4 and the tangential direction (X direction) of the two circumferences are arranged.
The squareness ratio Br/Bs of each direction) was measured. This is shown in the table below.

Further, as a comparative example, the squareness ratios Br/Bs of portions A and B of floppy disks of the same standard made by the so-called continuous method were similarly measured. This is shown in the table below.

As is clear from this result, in the example.

The squareness ratio Br/Bs in the X direction, that is, in the tangential direction of the 9 circumferences, is
The squareness ratio Br/Bs in the Y direction, that is, the radial direction, was particularly high, and was approximately twice as high. On the other hand, in the comparative example, the squareness ratio B in the X direction of part A and the Y direction of part B, which are parallel to each other, is
r/Bs is high, and the squareness ratio Br/B in the direction perpendicular to this is high.
s was a value 7.3 to 11.6% lower than the above direction.

〔Effect of the invention〕

As explained above, according to these inventions.

A disc-shaped magnetic recording medium can be manufactured that is oriented in the circumferential direction of the recording surface. by this.

A method of recording and reproducing by moving a magnetic head concentrically with respect to a recording surface has the effect of obtaining high input/output and improving recording density.

[Brief explanation of drawings]

FIG. 1 is a partially cross-sectional perspective view of a main part and an orientation roller of a magnetic paint coating device for a disk-shaped magnetic recording medium showing an embodiment of these inventions, and FIG. 2 is an enlarged view of section C in FIG. 1. Figure 3 is
An enlarged view of part D in FIG. 1 and FIG. 4 are plan views showing the measurement locations and directions of the squareness ratios of the floppy disks used as samples in the examples and comparative examples. 1 - Roller 2 - Magnetic pole line 3 - Magnet 4 - Recording surface 5 - Base a - Base rotation center b - Roller center axis Inventor Kiyoshi Suzuki

Claims (1)

[Claims] 1. A plurality of magnetic pole lines 2, 2... are provided in the width direction of the circumferential surface of the roller 1, and magnets 3, 3... are provided on both sides of the magnetic pole lines 2, 2... on both sides. The same magnetic poles of... are arranged, and the magnetic pole lines 2, 2... are arranged so that adjacent magnetic pole lines 2, 2... have opposite magnetic poles.
An orientation roller for a disc-shaped magnetic recording medium, characterized in that a butting magnetic pole is formed on the top thereof. 2. The orientation roller according to claim 1, wherein the magnets 3, 3, . . . are rare earth magnets embedded in the circumferential surface of the roller 1. 3. Roller 1 in the direction perpendicular to the rotation center axis a of the base 5
A plurality of magnetic pole lines 2,
2... are formed, and these magnetic pole lines 2, 2... are formed with butt magnetic poles so that the adjacent magnetic pole lines 2, 2... are opposite magnetic poles, and a base 5 coated with magnetic paint is attached. A method for orienting a disc-shaped magnetic recording medium, characterized in that the roller 1 is rotated around its central axis b, b while being rotated around the central axis of rotation a, and then the magnetic paint is cured. 4. The orientation method according to claim 3, wherein the base 5 is horizontally rotated. 5. The orientation method according to claim 4, wherein the means for applying the magnetic paint is a means for spraying the magnetic paint near the center of the base 5.