JPS5840265B2 - magnetic disk container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a container for storing and holding an entire magnetic disk used in a magnetic disk storage device.

With the rapid development of information processing technology in recent years, magnetic disk storage devices are also required to have high processing capabilities, and many improvements have been made to this end.

A typical example is the IBM 3348 data module, which incorporates a magnetic head into a conventional disk pack and stores and holds the whole thing in a single container, with a gap between the magnetic disk and the magnetic head. This eliminates various troubles and improves the flying distance (spaci) of the magnetic head.
ng), and the storage density (linear density) can be improved by that amount. Another way to improve the storage density is to use magnetic heads and magnetic heads to increase the track density. It is likely that improvements were made to the positioning mechanism.

However, in order to minimize the time required to position the magnetic head, a large current is instantaneously passed through the actuator that moves the magnetic head, which leaks a large amount of magnetic force lines to the outside and causes the electrical circuit containing the magnetic head to flow through the actuator that moves the magnetic head. This causes a lot of noise.

Furthermore, lines of magnetic force leaking from the motor used to drive the rotation of the magnetic disk can no longer be ignored as a cause of noise.

The object of the present invention is to provide a device that has the effect of shielding the above-mentioned noise entering the operating magnetic head and its accompanying electric circuit, and that applies a DC bias magnetic field to all the magnetoresistive heads used therein. An object of the present invention is to provide a magnetic disk accommodating body that can be simplified.

That is, the present invention provides a container that stores and holds the entire magnetic disk, and includes a high magnetic permeability magnetic film provided on the inner wall of the container, and a magnetic film provided on the inner wall of the container and in a portion facing the magnetic disk surface. The magnetization direction of a magnetoresistive head having at least one pair of permanent magnets, the pair of permanent magnets being substantially perpendicular to the surface of the magnetic disk and used as a reproducing head is set at 45 degrees with respect to the detection current. It is characterized by generating the DC bias magnetic field necessary for tilting.

Next, the present invention will be explained with reference to the drawings.

FIG. 1 schematically shows the present invention, in which a magnetic head 7 and its drive circuit 8 are held by an arm 9 facing each surface of a magnetic disk 2 fixed to a disk rotation shaft 1.
These arms 9 are fixed to a carriage 10 and connected to an actuator 11.

These magnetic disks 2 are attached to a belt 1 wound around a rotating shaft 1.
2 and is driven by a motor 13.

A feature of the present invention is that high magnetic permeability magnetic films 5 and 6 are provided inside these magnetic disk containers 3 and 4.

Various methods can be used as the material and method for forming the high permeability magnetic films 5 and 6, but one particularly preferred example is the known electroless plating method of nickel-iron-phosphorus alloy (for example, Co-authored by Hideo Ito and Tokuzo Kobe “
"Electroless plating/electroforming" (published by Maki Shoten, see page 52) is suitable.

This method is suitable when the containers 3 and 4 are made of metal, but if they are made of plastic, then electroless nickel plating (for example, Kaoru Aoya, ed. 'Plastic Plating°') (Published by Bookstore) (see pages 13 et seq.), then electroless plating of the nickel-iron-phosphorus alloy described above is performed.

Such a nickel-iron-phosphorus alloy has high magnetic permeability (magnetic permeability ≧1000) and conductivity (specific resistance 10μ, QC
rfL), it not only shields external magnetic fields, but also serves to shield external electric fields, thereby extremely reducing various noises coming into the magnetic head 7 and drive circuit 8.

Recently, magnetoresistive heads that utilize the magnetoresistive effect of ferromagnetic thin films have been attracting attention as the next generation high-density recording/reproducing and magnetic heads.

In order to improve the reproduction efficiency of such a magnetoresistive head, the magnetization direction of this ferromagnetic thin film is set 4 times relative to the direction of the detection current.
It is said that it is essential to tilt it by about 5 degrees, and for this reason, a configuration has been proposed in which a DC bias magnetic field is applied to each individual.

However, in a magnetic disk device that uses a large number of magnetic heads, providing each of these magnetic heads with a DC magnetic field generator not only complicates the structure and increases the cost, but also increases the The disadvantage is that the magnetic field (particularly the component parallel to the surface of the magnetic disk) acts on the magnetization pattern recorded on the magnetic disk, causing the information to be erroneous.

However, it can be seen that by using the above-mentioned container embodying the present invention, it is possible to easily generate a uniform DC bias magnetic field with few components parallel to the magnetic disk surface.

That is, by installing at least a pair of permanent magnets (for example, barium ferrite) shown as 14 and 15 in FIG. shows.

) can be added.

This is because the high magnetic permeability magnetic films 5 and 6 are behind the permanent magnets 14 and 15, and the lines of magnetic force coming from the respective magnets are superimposed.

The magnetic fields generated by the permanent magnets 14 and 15 need only tilt the magnetization direction of the ferromagnetic thin film of the magnetoresistive head by about 45 degrees with respect to the current direction (usually parallel to the magnetic disk surface); This is the strength of Ersted.

Even if a magnetic field of this magnitude is applied perpendicularly to the magnetic disk 2, if the coercive force of the magnetic film of the magnetic disk 2 is 300 microns or more and the film thickness is 1 micron or less, the magnetization pattern written therein will hardly be affected. It has been experimentally confirmed that it has no effect.

Therefore, the reliability of the information will not be reduced.

Figure 2 shows this invention in the IBM 3348 data model.
Since the module is a magnetic head module, a magnetic head 20 is mounted facing each surface of a magnetic disk 202 fixed to a disk rotation shaft 201.
7 and its drive circuit 208 are held by an arm 209, and the arm 209 is fixed to a carriage 210.

Similar to the example shown in FIG. 1, the feature of the present invention is that a high magnetic permeability magnetic film 205 is provided inside the magnetic disk housing 203, and a magnetoresistive head is used as a reproducing head. When in use, at least one pair of permanent magnets 214 and 215 are installed.

The material and manufacturing method of the high permeability magnetic film 205 and the effects of the permanent magnets 214 and 215 are the same as in the embodiment shown in FIG.

As described above, this invention can be used not only to shield external radio waves but also to shield external magnetic fields (especially magnetic fields generated by driving the actuator 11 located near the magnetic head, magnetic fields from the motor used to rotate the magnetic disk, etc.). This is an extremely effective magnetic disk accommodating body, and for magnetic disk accommodating bodies in which many of the above-mentioned magnetoresistive heads are used as reproduction magnetic heads, instead of providing a bias magnetic field generator for each magnetoresistive head, Since it is provided with at least one pair of permanent magnets 14 and 15, there is an advantage that the structure of the reproducing magnetic head is extremely simplified and can be manufactured at low cost.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, in which 1 and 201 are rotating shafts, 2 and 202 are magnetic disks, 3, 4 and 203 are containers, 5°6 and 205
7 and 207 are magnetic heads; 8 is a high permeability magnetic film; 7 and 207 are magnetic heads;
and 208 is a drive circuit, 9 and 209 are arms, 1
0 and 210 are carriages, 11 is an actuator, 12 is a belt, 13 is a motor, 14, 15, 214
and 215 are permanent magnets.

Claims (1)

[Claims] 1 A container that stores and holds the entire magnetic disk used in a magnetic disk device, which includes a high magnetic permeability magnetic film provided on the inner wall of the container, and a portion of the inner wall of the container that faces the magnetic disk surface. The direction of magnetization of a magnetoresistive head, which has at least one pair of permanent magnets provided, the pair of permanent magnets being substantially perpendicular to the surface of the magnetic disk and used as a reproducing head, relative to the detection current. 45°
A magnetic disk housing generating a direct current bias magnetic field necessary for tilting the disk to a certain degree.