JPS5979416A - Magnetic recorder - Google Patents

Abstract

PURPOSE:To minimize the noise level by having no oblong for the tip form of a main magnetic pole with different values of thickness set at the center part and the circumference part of the main magnetic pole and having a nonlinear side at the outflow side of a recording medium to obtain the maximum level of the reproduced signal output. CONSTITUTION:In a record mode a side 9 of a main magnetic pole 2 is rectilinear at the inflow side of a recording medium 1 with a side 10 formed in a chevroned shape at the outflow side 11 of the medium, respectively. A magnetization pattern 11 remaining at the medium 1 is also chevroned in accordance with the form of the side 10, and therefore the form of the side 9 of the medium inflow side does not substantially remain as magnetization. The record magnetization remains on a track 111 and a track 112. In a reproduction mode with this head, the side 9 is rectilinear at the medium inflow side. While residual magnetizations 111 and 112 on the tracks are chevroned, and therefore the side 9 covers over plural record bits. Then the change of magnetic flux due to magnetization on the medium 1 is weakened by an azimuth loss and not virtually converted into a reproduction output.

Description

Detailed Description of the Invention: A magnetic recording device that performs perpendicular magnetization recording, in which the shape of the main pole tip of the magnetic head has different thicknesses at the center and periphery, and in addition, the side on the medium outflow side is non-straight. Regarding.

High-density magnetic recording systems are becoming increasingly popular as image recording devices such as VTRs and information recording devices such as floppy disks and Winchester are made smaller and more compact. However, in the magnetic recording system, the conventional horizontal magnetization recording system is already reaching its limit in recording density. Perpendicular magnetization recording is attracting attention as a new high-density magnetic recording method. This method uses a thin film of an alloy such as cobalt chromium. By sputtering or vapor depositing these alloys on a PET tape or aluminum disk under certain conditions, the direction of magnetization can be made perpendicular to the surface of the recording medium. Such properties can also be obtained by coating barium ferrite fine particles with a binder. Furthermore, by coating conventional iron oxide fine particles under certain processing conditions, such vertically oriented recording media can have a vertical magnetization component as well as a horizontal magnetization component. As the recording density increases, the demagnetization effect decreases. Therefore, it is possible to significantly improve the recording density compared to the horizontal magnetization method.

The recording/reproducing magnetic head for such perpendicular recording is not the so-called ring-type head used in the conventional horizontal magnetization method, but is disclosed in, for example, Japanese Patent Application Publication No. 52-1'3470.
A single magnetic pole head such as that described in 6) is used.

If a perpendicular magnetization method is used to perform high-density recording, it is expected that the recording wavelength of the conventional horizontal magnetization method, which is 2 to 6 microns, will be reduced to less than 1 micron.

In order to perform high-density recording more efficiently, recording tlv-,l
Open. We must think about how to use it efficiently. Currently, floppy disks are equipped with trimming heads on both sides of the recording/reproducing head body, each having a head width approximately half that of the recording/reproducing head, so that signals of adjacent tracks are not reproduced even if the track position tu shifts. That is, both f)ill K gaps of the required track are present. In the case of Winchester, there is no head for trimming, but the track pitch is about twice the width of the head, and there still remain portions on both sides of the recording track that do not contribute to recording and reproduction. In the case of a VTR tape, there is also a gap called a guard band that is approximately half the width of the head, and approximately one-third of the tape medium surface is not used for writing purposes.

In the case of VTR tapes, a method of effectively utilizing this is to use a plurality of heads and to bring the recording tracks closer together by tilting the angle of the head gap between the heads responsible for adjacent tracks. This method is called inclined azimuth recording, and the influence of adjacent tracks becomes smaller as the recording wavelength becomes shorter, the track width becomes wider, and the azimuth angle becomes larger. However, if the azimuth angle is increased, the relative speed between the head and the tape decreases, and the reproduction output decreases. Furthermore, if the azimuth angle is increased, even a slight track deviation will cause the reproduced signal to become discontinuous between the two heads. For these reasons, the azimuth angle cannot be set very large, and crosstalk of low frequency signals cannot be prevented. In particular, this azimuth recording requires a plurality of magnetic heads, and furthermore, adjustment between these heads is difficult.

In the case of disks, this method of effectively utilizing the entire surface of the recording medium is considered difficult, and in the case of tapes, it has been achieved by the azimuth recording method, but it has a number of disadvantages.

The present invention eliminates these drawbacks, shortens the recording wavelength, and effectively utilizes the recording medium surface without creating wasted areas to achieve high-density magnetic recording, thereby completing an ultra-compact high-density magnetic recording device. It is something.

An object of the present invention is to provide a high-density magnetic recording device by eliminating gaps such as guard bands on the surface of a magnetic recording medium of the magnetic recording device.

Another object of the present invention is to provide a compact, high-density magnetic recording device at low cost that performs azimuth recording using the minimum number of heads required.

The basis of the present invention is a magnetic recording medium capable of perpendicular magnetization recording (i.e., cobalt chromium alloy thin film, barium alloy) 9
A particle coating film 2 isotropically oriented iron oxide fine particle coating 1 charcoal is used, and a single magnetic pole head is used as the magnetic head. A particularly important point is that the surface of the single-pole head facing the medium, that is, the cross-sectional shape of the tip is not the usual rectangular shape of the M11. The present invention is characterized by the shape of the side on the medium inflow side and the side on the medium outflow side of the cross section of the tip, particularly the side on the medium outflow side.

FIG. 1 shows the basic structure of a conventional perpendicular magnetization recording system. In FIG. 1 (α), a tape or disk-shaped recording medium 1 is constructed of a PET, polyimide, or aluminum substrate on which a cobalt-chromium alloy thin film, barium ferrite film, or barium ferrite film is formed. A main magnetic pole 2 and an auxiliary magnetic pole 3 are arranged above and below. The main pole 2 is usually formed of a thin film with high magnetic permeability. The auxiliary magnetic pole 3 is usually formed of ferrite or the like around which a coil 4 is wound. The magnetic flux formed in the auxiliary magnetic pole B by passing a current through the coil 4 is conducted to the main magnetic pole 2, and magnetization is left on the recording medium by the tip of the main magnetic pole 2. In this case, the head is arranged on both sides of the recording medium 1, resulting in a complicated structure, so an example in which the head is arranged on one side is shown in FIG.
(required).

In this case as well, the arrangement of the recording medium 1 and the main magnetic pole 2 remains the same, but
A ferrite 5 is brought into contact above the main magnetic pole 2, and a coil 6 is wound around it. Even with such a configuration, the magnetization remaining in the recording medium 1 is exactly the same as that shown in FIG. 1 (α).

FIG. 2 shows the situation during recording in more detail.

The magnetization remaining in the recording medium 1 depends on the shape of the tip of the main magnetic pole 2, as described above. Since the main pole 2 is usually formed of a thin film, its tip has a rectangular cross-sectional shape. That is, the long side controls the recording width, and the short side controls the minimum recording bit length. Normally, the recording medium 1 and the main pole 2 move relative to each other, so in FIG. 2, the direction of movement of the medium is indicated by arrow A.
The moving direction of the main magnetic pole 1 is indicated by an arrow B. A and B are naturally in opposite directions, and the magnetization 7 remains behind the movement of the main magnetic pole 2, that is, on the medium outflow side. Therefore, the width of the pattern of magnetization 7, that is, the track width, is determined by the width of the main magnetic pole 2. The length of each bit of the magnetization 7 is determined by the relative moving speed of the recording medium 1 and the rear side of the main magnetic pole 2, that is, the side on the medium outflow side. The bit length is determined by the time that one signal is applied and the relative movement speed.

FIG. 6 shows the situation during playback. Recording tracks 71 and 72 are magnetized on the recording medium 1.

The portion 8 to be reproduced by the main pole 2 is shown in dotted lines. In this case, the head deviates from the track 72 and straddles the adjacent track 71. The amount of noise that enters the Shun track is induced into the main magnetic pole 2 as noise. Therefore, the reproduced signal output becomes small and the noise becomes large. To avoid this, blank areas are usually left as guard bands on both sides of the recording track.

In the present invention, the tip shape of the main magnetic pole is not rectangular, but has different thicknesses at the center and periphery, and the edge on the media outflow side is non-linear to maximize the reproduced signal output and minimize the noise level. .

FIG. 4 shows an example of the shape of the main pole tip of the present invention.

Arrow A indicates the direction of medium movement, and arrow B indicates the direction of head movement. (σ), Ch) has a roof-shaped side on the medium outflow side, that is, a chevron shape.

CC) and Cd) have circular edges on the medium outflow side. (g) and CI) have a rectangular shape on the medium outflow side. (y) e (h) = (') further assumes that the medium inlet side is also non-linear. The pattern shown above is thicker in the center than in the periphery. ()゛) and (7C) show examples of patterns in which the center part is thinner than the peripheral part. These formations are performed by a combination of head substrate etching, mask sputtering, etc. FIG. 5 shows a situation in which recording is performed according to the present invention. The side 9 of the medium inflow [tllll] of the main magnetic pole 2 is a straight line, and the side 10 on the medium outflow side has a chevron shape. The magnetization pattern 11 remaining on the recording medium 1 has a chevron shape that mirrors the shape of the side 10 on the medium outflow side. The shape of the side 9 on the medium inflow side does not substantially remain as magnetization.

FIG. 6 shows the state of reproduction according to the present invention. Recorded magnetization remains in tracks 111 and 112. The main magnetic pole shape is the same as that shown in FIG. In reproduction by this head, the side 9 on the medium inflow side is a straight line. On the other hand, since the residual magnetizations 111 and 112 on the track have a chevron shape, the side 9 on the medium inflow side spans a plurality of recording bits, and changes in magnetic flux due to magnetization on the medium are smoothed out by azimuth loss, resulting in almost no reproduced output. This does not change even if the head is perfectly aligned with the track position. On the other hand, on the side 10 on the medium outflow side, the maximum output is obtained when the original coincides with the track position, and the output decreases when the track deviates. However, the noise level remains the same. Therefore, by finely adjusting the head to a position where the maximum output can be obtained, the head can be perfectly aligned with the track, thereby preventing crosstalk with adjacent tracks.

Furthermore, when reproducing with a conventional main magnetic pole, a thin film corresponding to the minimum bit length must be used to reproduce high-density recording, and as a result, the higher the density, the lower the reproduction signal output. In the present invention, there is no need to reduce the thickness of the main magnetic pole even when reproducing high-density recording, so the reproduction signal output during high-density recording does not decrease drastically. Although the present invention is basically possible by combining a ring head with a horizontally magnetized recording medium, from the viewpoint of ease of manufacturing the head, it is preferable to perform recording and reproducing with a main pole on a medium with a perpendicular magnetization component. most suitable. To describe the basics of the present invention in more detail, the shape of the head tip is characterized in that the shape of the side on the medium outflow side is not perpendicular to the head traveling direction or one-sided flow, but double-flow. Therefore, such a shape is difficult to form with a ring head, but is easy to form with the main pole of a single-pole head.

The present invention can of course be applied to a wide range of applications, and can be effectively utilized for both disks and tapes, but the wavelength characteristics of recording and reproduction will suffer from a decrease in output, which was conventionally controlled by the thickness of the main pole film. The elimination of wavelength ranges has made it possible to utilize a wide range of wavelengths. For this reason, it is considered to be particularly effective for VTRs or image recording that utilize a wide band. In particular, in the case of VTRs, azimuth recording, which was conventionally done with two heads, can now be done with one head, making it possible to wind the tape in α or Ω windings and reduce the cylinder diameter to half that of conventional VTRs. has been significantly reduced in size and weight.

In addition, since there is only one head in this case, there is no need to precisely adjust the positions of the two heads, and wow and flutter caused by differences in the characteristics of the two heads are also eliminated. Also, since there is no need for a trimming head for discs, and there is no need for a guard band, the head shape is simplified.
The recording capacity of the disc has also doubled.

As detailed above, the magnetic recording device of the present invention has very high industrial utility value.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating the present invention. 1...Recording medium 2...Main magnetic pole 6...Auxiliary magnetic pole 4... Coil 5・・・・・・
... Ferrite 6 ... ... Coil 7 ... Recording magnetization 71 ... Recording track 72 ... Recording track 8 ... ...Het position? ......Medium inflow side 10...Medium flow top side 11...Recording magnetization 111...Recording track 112...Recording track 12... Head position and above Applicant Suwa Seikosha Co., Ltd. Agent Patent attorney Tsutomu Mogami

Claims (1)

[Claims] In a magnetic recording device using a recording medium containing a perpendicular magnetization component and equipped with a main a-pole type magnetic disturbance, the thickness of the central part and the peripheral part of the tip shape of the surface of the main pole facing the medium is Q! A magnetic recording device that makes @.