JPH0740415B2 - Magnetic recording device - Google Patents

Description

The present invention relates to a magnetic recording device used for recording / reproducing various analog / digital signals and the like, and more particularly to a magnetic recording device such as a sheet magnetic disk. The present invention relates to a magnetic recording device in which a flexible disk-shaped recording medium is rotatably housed in a cassette housing.

(Prior Art) As a magnetic recording apparatus (or recording medium body) of this type, a structure having a structure as shown in FIGS. 2 and 3 has been conventionally known.

In this magnetic recording device, a dish-shaped core member (hub) 2 is fitted into a through hole of a disk-shaped recording medium 1 having a through hole 1a at the center, and an edge portion of the through hole 1a of the disk-shaped recording medium 1 is Hub 2
Is adhered to the edge portion of the sheet via an annular double-sided adhesive tape 3. The disc-shaped recording medium 1 includes a cassette housing 5 composed of an upper half 5a and a lower half 5b having a circular hole 6 in the center, via liners 4 and 4 made of a synthetic resin nonwoven fabric.
In addition, the cylindrical portion of the hub 2 is loosely fitted in the circular hole 6 so as to be rotatably housed and mounted.

Further, in such a magnetic recording device, when a 3.5-inch disk-shaped recording medium is used, a recording portion having a width of 120 μm and 6
A track consisting of a 0 μm non-recorded area is provided on one side of the medium.
0 tracks are formed, and for writing and reading, the hub 2 of this magnetic recording device is engaged with the spindle of the recording / reproducing device,
This is done by sliding the head along this track while rotating at 300 rpm.

(Problems to be Solved by the Invention) As described above, in the magnetic recording apparatus, since tracks are formed at a high density on the surface of the disk-shaped recording medium, the head of the recording / reproducing apparatus and the recording surface of the disk-shaped recording medium are formed. High accuracy is required for the relative positional relationship.

However, since the double-sided adhesive tape for fixing the disc-shaped recording medium and the hub usually uses an adhesive whose hardness changes slowly with time, the inner periphery of the through hole 1a of the disc-shaped recording medium is often used. The relative position between the surface and the hub fitted and mounted in this through hole 1a is displaced, the reproduction output becomes insufficient, and in some cases the recording track and the reproduction track do not match, making it impossible to reproduce. There was a problem of becoming.

In order to avoid such a problem, it may be possible to weld the hub of the disk-shaped storage medium with an ultrasonic welding device. However, when welding is performed with such an ultrasonic welding device, the disk-shaped storage medium is ultrasonically welded. There is a problem that dust is generated from the recording medium and causes dropout.

It is also conceivable to integrally form the disc-shaped recording medium and the hub, but in such a method, the support for the disc-shaped recording medium may be damaged by the heating during the forming.

The present invention has been made to solve such a conventional problem, and securely fixed the relative positional relationship between the disc-shaped recording medium and the hub without fear of dropout due to dust or damage due to heating during molding. An object is to provide a magnetic recording device. [Structure of the Invention] (Means for Solving the Problems) That is, the magnetic recording apparatus of the present invention is a disk-shaped recording medium having a through hole in the center, and both sides of which the ring-shaped edge is fitted into the through hole. A recording medium body composed of a dish-shaped core member joined by an adhesive tape, and a circular hole for spindle engagement at the center of at least one of the upper half and the lower half, and the recording medium is provided in this circular hole. And a cassette housing for rotatably storing and mounting a core member of the main body, wherein the recording medium main body is eccentrically adhered to (attached to) a through hole of a disk-shaped recording medium. Then, one portion of the edge portion of the through hole of the disk-shaped recording medium is caused by the rotation operation.
It is characterized in that it is fixed to the dish-shaped core member.

The amount of eccentricity between the disc-shaped recording medium of the present invention and the dish-shaped core member is usually 0.2 to 1.0 mm, preferably 0.5 to 1.0 mm.

In the present invention, when the disc-shaped recording medium is eccentrically mounted on the core member, the hole diameter of the through hole of the disc-shaped recording medium is formed to be larger than the outer diameter of the fitting portion of the core member by an amount corresponding to an eccentric amount. Then, the edge of the through hole of the disc-shaped recording medium is adhered to the edge of the hub via the double-sided adhesive tape, and then mounted on the spindle, and the disc-shaped recording medium has a larger adhesive force than the double-sided adhesive tape. It may be rotated at a rotational speed sufficient to generate a centrifugal force (the rotational speed at the time of ordinary recording and reproduction is sufficient immediately after the adhesion).

In this way, when the disc-shaped recording medium is rotated, the disc-shaped recording medium is moved by the centrifugal force with respect to the dish-shaped core member.
When moving in the direction, one part of the edge of the through hole comes into contact with one part of the outer periphery of the core member (hub) and is stabilized in this state.

(Operation) In the magnetic recording apparatus of the present invention, the disk-shaped recording medium is eccentrically attached to the core member and adhered (attached / attached), so that the eccentricity increases the radius of gyration during subsequent reproduction and recording. A centrifugal force larger than the other parts always acts on the portion where the double-sided adhesive tape solidifies, and thus the disc-shaped recording medium does not move from this position and is securely fixed at this position.

More specifically, the problem of track position deviation between recording and reproduction or signal rewriting is due to the relative position of the disc-shaped recording medium with respect to the dish-shaped core member (hub). Therefore, if the disk-shaped recording medium is fixed in a normal positional relationship and does not deviate over time, each track position of the disk-shaped recording medium that is rotated by the rotation of the hub is also fixed. The problem of track deviation during traveling of the head can be solved even when the head is slightly eccentric with respect to the hub. That is, when the hub combined with the disk-shaped recording medium is mounted on the spindle and rotated, the disk-shaped recording medium has the center of rotation of the hub as the center of rotation. It becomes a concentric circle due to rotation around the center, and this state is finally held. The concentric circles are slightly deviated from the center of the circle of the disc-shaped recording medium, but the eccentricity is only about 0.2 to 1.0 mm, which disturbs the stability of the rotary character or causes the rotation. Almost no deterioration in dock accuracy due to turbulence is observed.

(Example) Next, the Example of this invention is described.

As shown in FIG. 1, the diameter of the cylindrical portion of the hub is 24.5 mm and the diameter of the through hole 1a of the disc-shaped recording medium 1 is 25 mm.
The hub 2 is attached by the annular double-sided adhesive tape 3 with a thickness of 0.2 mm.
The edge portion of the through hole 1a of the disc-shaped recording medium 1 was adhered to the flange portion of. Next, the disk-shaped recording medium 1 is
In the same manner as shown in the figure, a cassette housing composed of an upper half and a lower half was rotatably accommodated, mounted on a spindle of a recording / reproducing apparatus, and rotated at 300 rpm for 5 minutes.

After that, when the cassette housing was opened and the disc-shaped recording medium was observed, a part of the edge portion of the through hole of the disc-shaped recording medium was fixed in a state of being in contact with the cylindrical portion (outer peripheral surface) of the hub. .

Next, a mark is added to the contact position, the disc-shaped recording medium is housed / mounted again in the cassette housing, mounted on the spindle of the recording / reproducing device, rotated at 300 rpm for 100 hours, and then the cassette housing is opened. When the disc-shaped recording medium was observed, the contact position between the disc-shaped recording medium and the cylindrical portion of the hub was unchanged.

[Advantages of the Invention] As described above, the magnetic recording apparatus of the present invention is capable of performing relative operation between the disk-shaped recording medium and the dish-shaped core member without fear of dropout due to dust or the like and damage due to heating during molding. The positional relationship can be reliably fixed, and it is possible to reliably prevent the reproduction output from becoming insufficient and the recording track and the reproduction track from becoming inconsistent.

[Brief description of drawings]

FIG. 1 is a sectional view showing an essential part of the present invention, FIG. 2 is a sectional view showing the structure of a conventional magnetic recording apparatus, and FIG. 3 is an enlarged sectional view showing the essential part. 1 ... Disc-shaped recording medium 1a ... Through hole 2 ... Dish-shaped hub 3 ... Annular double-sided adhesive tape 4 ... Synthetic resin non-woven liner 5 ... Cassette housing 5a ... Upper half 5b ... Lower half

Claims (1)

[Claims] 1. A disk-shaped recording medium having a through hole in the center,
And a recording medium body composed of a dish-shaped core member that fits into the through hole and has an edge joined with an annular double-sided adhesive tape, and a spindle for engaging the central portion of at least one of the upper half and the lower half. And a cassette housing in which a core member of the recording medium body is loosely fitted and rotatably accommodated and mounted in the circular hole, and the recording body body is a through hole of a disc-shaped recording medium. In addition, the dish-shaped core member is eccentrically adhered to the disc-shaped recording medium, and one portion of the edge portion of the through hole of the disc-shaped recording medium comes into contact with the dish-shaped core member to be fixed with rotation. Characteristic magnetic recording device.