JPH06274876A - Orienting device for magnetic recording medium - Google Patents

Abstract

PURPOSE:To realize the magnetic recording medium having excellent characteristics as a recording medium by diagonal orientation of magnetic powder by permanent magnets. CONSTITUTION:The permanent magnets 2 which forms magnetic field approximately parallel with the magnetic recording medium 1 and the permanent magnets 3 which form magnetic fields approximately perpendicular thereto are arranged in the positions on both sides of the medium 1. The magnetic fields H1 are generated on the magnetic coating film surfaces of the medium 1 as the sum of the vectors of the magnetic field components H2 and H3 by the respective magnets to orient the magnetic powder included in the coating film surfaces in a diagonal direction. The magnetic field intensity is limited within a range of 20 to 100% of the coercive force of the magnetic powder, by which the characteristics of the medium 1 are enhanced.

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 orienting apparatus for orienting magnetic powder in a magnetic coating film surface obliquely to the coating film surface.

[0002]

2. Description of the Related Art As a magnetic recording method for a magnetic recording medium,
There are two methods, a longitudinal recording method that uses magnetization in the longitudinal direction of a recording layer of a magnetic recording medium and a perpendicular recording method that performs recording by magnetization in the thickness direction.
On the other hand, the latter has the contradictory disadvantage that each characteristic is inferior in the long wavelength region.

In order to eliminate the disadvantages of these methods and to obtain well-balanced characteristics from the short wavelength region to the long wavelength region,
Japanese Unexamined Patent Publication (Kokai) No. 3-35420 discloses an orienting device for orienting magnetic powder in a magnetic layer in a direction oblique to a surface of a magnetic coating film by a solenoid coil or an electromagnet.

It is also suggested that by using a permanent magnet instead of the solenoid coil or electromagnet, the DC power supply required by the solenoid or electromagnet can be eliminated and the device can be made compact.

[0005]

However, when a permanent magnet is used for the orientation of the magnetic powder, if the magnetic field strength is too strong, the orientation of the magnetic powder becomes uneven and the surface roughness of the magnetic recording medium increases, resulting in running durability. If the magnetic field strength is too weak, there is a problem that the orientation is not achieved.

Further, the permanent magnet has a problem that the magnetic field strength is not constant over the entire magnetic pole surface and the magnetic force is remarkably high at both ends of the magnetic pole, so that the orientation direction of the magnetic powder becomes uneven. As a result of solving and improving these points, the present invention provides a magnetic recording medium orientation device capable of uniformly orienting magnetic powder in a magnetic layer in a predetermined oblique direction by the magnetic field strength of a permanent magnet. It is intended.

[0007]

The above object is to apply a pair of first permanent magnets sandwiching a magnetic coating film surface and applying a magnetic field component substantially parallel to the magnetic coating film surface, and a substantially perpendicular magnetic field component. A pair of second permanent magnets for aligning the magnetic powder contained in the magnetic coating film surface in an oblique direction, which comprises a first permanent magnet or a second permanent magnet. This is achieved by an aligning device for a magnetic recording medium, characterized in that the orientation of the magnetic powder is made constant by changing the distribution of the orientation magnetic field strength.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetic recording medium orienting device according to the present invention will be described with reference to FIGS.

As shown in FIG. 1A, the orienting device comprises a pair of first permanent magnets 2 and second permanent magnets 3 which sandwich a long magnetic recording medium 1 from above and below.

The permanent magnets 2 and 3 have rectangular magnetic pole faces arranged in parallel and at right angles to the magnetic coating surface 1a and the medium back surface 1b of the magnetic recording medium 1, respectively. It is arranged so that the drying of No. 1 is completed between the magnetic pole faces.

A magnetic field substantially perpendicular to a magnetic field substantially parallel to the magnetic coating surface 1a of the magnetic recording medium 1 is formed between the magnetic pole surfaces by the permanent magnets 2 and 3 and is perpendicular to the parallel magnetic field component H2. It is possible to generate a magnetic field H1 in an oblique direction with respect to the magnetic coating film surface 1a as the sum of the vectors of the various magnetic field components H3.

Since the angle φ of the magnetic field H1 formed by the magnetic coating surface 1a changes depending on the magnitudes of the magnetic field components H2 and H3, the above-mentioned angle can be obtained by appropriately selecting the magnetic field strengths of the permanent magnets 2 and 3. It is possible to arbitrarily determine the value of φ.

As shown in FIG. 2, the magnetic field strength between the magnetic pole faces is evenly distributed along the length direction of the magnetic pole faces with respect to the permanent magnet 3, whereas the permanent magnet 2 is distributed with an increase at both ends. Is not uniform, the above-mentioned magnetic field H
It is unavoidable that the angle φ of 1 slightly fluctuates, and as a countermeasure against this, the permanent magnet is partially cut as shown in FIG.

That is, the orienting device shown in FIG. 3 (a) is an example in which a permanent magnet 2A having a convex cut on the magnetic pole surface is used, whereby a uniform magnetic field strength is obtained along the length direction of the magnetic pole surface. A distribution is obtained, and the angle φ of the magnetic field H1 can be stably obtained.

On the other hand, the orienting device shown in FIG. 3 (b) is an example in which a permanent magnet 3A is used in which the thickness of the magnetic pole surface at the center is cut to be thin, whereby the distribution of the magnetic field strength of the permanent magnet 2 is changed. A corresponding magnetic field strength is obtained, and the orientation direction of the magnetic field H1 is stabilized.

Further, by arranging the magnetic poles of the permanent magnet 3 upside down, it is possible to generate the magnetic field H1 by reversing the direction of the magnetic field H1 with respect to the magnetic coating film surface 1a as shown in FIG. 1 (b). Is.

Next, the characteristics of the magnetic recording medium oriented by the above-mentioned orientation device will be described based on each embodiment.

As the magnetic recording medium used in the experiment, Fe--Al metal powder (Examples 1 to 3, each comparative example) or CO-containing γ-Fe ₂ O ₃ powder (Examples 4 and 5) was used as the magnetic powder. ^{_{use, -SO 3 M 1, -SO 2}} M 1, -OSO 3 M 1, -COOM 2, -OH and monovalent ^{- {(OM 2) (OM} 3)} P = 0, -O {( OM ² ) (OM ³ )} P = 0
A sample tape was used as a magnetic coating surface by adding a binder having a negative functional group such as.

The sample tapes were orientated obliquely by using the orienting device of the present invention, and the samples of Examples 1 to 5 as shown in Table 1 according to the coercive force (HC) of the magnetic powder and the applied magnetic field strength at that time. Created the material.

In order to compare the characteristics with each of the above-described Examples, Comparative Examples 1 and 2 in which only the vertical direction and the parallel direction are oriented under the same conditions as in Example 2, and further, both of them are obliquely oriented and have a magnetic coercive force A comparative example 3 in which the magnetic field strength is the same as 1800 Gauss but the magnetic field strength is 200 Gauss and a comparative example 4 in which the magnetic field strength is 2000 Gauss
Sample materials of are also prepared.

Table 2 shows the results of the characteristic comparison by the sample materials of the above-mentioned respective examples and comparative examples.
Both of the electromagnetic conversion characteristics are such that the applied magnetic field strength is 20
% Sample materials (Examples 1 to 5) having an oblique orientation in the range of 100% to 100% are predominant, and the sample materials oriented only in the vertical direction or the parallel direction and the magnetic field coercive force of the applied magnetic field strength while obliquely orienting. It was revealed that the sample materials exceeding 20% to 100% (Comparative Examples 1 to 4) were significantly inferior.

Further, in terms of running durability, each of the examples can withstand 200 or more passes (○), while each of the comparative examples has a large value of 150 times (△) to 100 to 50 times (x). It was confirmed to be inferior.

From the above results, it should be considered that the magnetic field strength applied to the surface of the magnetic coating film in the oblique orientation by the permanent magnet is optimally within the range of 20% to 100% of the coercive force of the magnetic powder. You can

The surface roughness is R by using a tarry step.
_10Z measured, RF-OUT of the electromagnetic conversion characteristics records a single wave of 9MH _Z to each sample article was it represents the output level at the time of reproducing the signal with a comparison with Comparative Example 2. The running durability is S-550 under the environment of temperature 20 ° and humidity 60%.
(Manufactured by Sony Corporation) was repeatedly reproduced, and it was judged by the occurrence of edge damage.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

The present invention makes it possible to properly orient magnetic powder in a predetermined oblique direction by the parallel and perpendicular magnetic field components formed by two sets of permanent magnets. As a result,
An orienting device for a magnetic recording medium having a magnetic coating surface excellent in electromagnetic conversion characteristics and running durability has been provided.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of an orienting device according to the present invention.

FIG. 2 is an explanatory diagram showing a distribution of magnetic field strength.

FIG. 3 is a modified block diagram of the orientation device.

[Explanation of symbols]

 1 magnetic recording medium 1a magnetic coating surface 1b medium back surface 2,2A (first) permanent magnet 3,3A (second) permanent magnet H1 magnetic field H2 (parallel direction) magnetic field component H3 (vertical direction) magnetic field component

Claims (2)

[Claims] 1. A pair of first permanent magnets sandwiching a magnetic coating surface and applying a magnetic field component substantially parallel to the magnetic coating surface, and a pair of second permanent magnets applying a substantially perpendicular magnetic field component. A magnetic recording medium orienting device for orienting magnetic powder contained in the surface of a magnetic coating film in an oblique direction by means of a distribution of orientation magnetic field strength of either the first permanent magnet or the second permanent magnet. The orientation device of the magnetic recording medium is characterized in that the orientation direction of the magnetic powder is made constant by changing 2. The orienting device for a magnetic recording medium according to claim 1, wherein the intensity of the orienting magnetic field applied to the magnetic powder is in the range of 20% to 100% of the coercive force of the magnetic powder.