JPH04157686A - Disk cartridge - Google Patents

Abstract

PURPOSE:To enable wobbling of a rotary disk to be minimized and running property of the disk to be improved by setting a surface roughness of a sliding surface of a protruding member which contacts with a magnetic disk to be within a specific range. CONSTITUTION:A surface roughness Ra of a surface of a magnetic disk side of protruding members 2 and 3 which are placed at upper and lower parts of a main inner wall surface of a cartridge case 1 which stores a magnetic disk 4 so that it can rotate within the inside in a status where the protruding members 2 and 3 oppose each other with the magnetic disk 4 in-between is set to 0.01 mum - 10mum. If the Ra is equal to or less than 0.01 mum, the disk is easily adhered onto the protruding members, thus enabling sliding property to be inferior and causing rotation unevenness of the disk to be produced. On the other hand, if the Ra is equal to or larger than 10 mum, marking may enter the disk surface easily. Thus, it becomes possible to improve recording/ reproduction characteristics and durability to be improved remarkably and to obtain a magnetic disk with a high reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a disk cartridge in which a disk such as a flexible magnetic disk is rotatably housed in a jacket or a thin case.

More specifically, the present invention relates to a disc cartridge that suppresses vibration of the disc contained therein during rotation.

[Prior Art] Magnetic recording is a rewritable recording method that is being applied in a wide range of fields.

In order to increase recording efficiency in magnetic recording, it is necessary to reduce the distance between the magnetic head and the recording medium as much as possible.

In order to further improve durability, it is necessary to improve the sliding contact between the magnetic head and the disk, that is, the ``head touch'', and for this reason, the flatness of the recording medium becomes a problem.Especially in the case of floppy disks, Since the disk is flexible, it is easily deformed during the manufacturing process, and the flatness of the disk is likely to be impaired.

In addition, in the case of metal thin film floppy disks, which have recently been expected to be used as high-density recording media, curling tends to occur during the manufacturing process due to the difference in coefficient of thermal expansion between the metal thin film and the substrate film, which causes poor recording efficiency and durability. It has become.

Therefore, in order to improve the flatness of the disk, research is being conducted on magnetic recording media in which a recording disk whose surface has been stretched is fixed to a rigid support. (IEEEETRANS NAG
VOL NAG-21, No. 5. PP1511～
1514. (SEPTEMBER 1983) This surface-stretched disk causes less deformation of the medium during rotation than conventional floppy disks. However, there are disadvantages in that the surface pressure applied to the head during contact with the head is large, and it is difficult to tension the disk with uniform tension.

[Problems to be Solved by the Invention] The present invention provides a disc recording medium which is composed of a jacket or a thin film case and which can flatten the disc itself by rotating the disc, and thus has excellent recording and reproducing characteristics and durability. The purpose is to provide recording media.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a magnetic disk and a cartridge case that rotatably accommodates the magnetic disk, and the main inner wall surface of the cartridge case is In a disk cartridge in which at least one set of protruding members are disposed above and below, facing each other with the magnetic disk sandwiched therebetween, a surface roughness Ra of the surface of the protruding member on the magnetic disk side is 0.01 μm. ~10μ
To provide a disc cartridge characterized in that it is within the range of m.

[Function] As described above, according to the present invention, the surface roughness Ra of the sliding surface of the protruding member that comes into sliding contact with the magnetic disk is set to 0°01 μm to 1 μm.
By setting within the range of 0 μm, the surface runout of the rotating disk can be controlled to be as small as possible, and the running performance of the disk can be improved.

The range of surface roughness Ra of the sliding contact surface of the projection member is 0.01
A range of μm to 10 μm is desirable. Ra is 0.01μm
If it is less than this, the disk will tend to stick to the protruding member and the sliding property will deteriorate, which may cause uneven rotation of the disk, which is not preferable.

Moreover, if Ra is 10 μm or more, the disk surface is likely to be scratched.

In the disk cartridge of the present invention, the vertical gap between the upper and lower projection members for preventing surface runout of the disk, which are provided on the inner surface of the cartridge case to face the inner and outer circumferential surfaces of the rotating disk, is the magnetic disk used. Although it varies depending on the thickness of the disk, it is generally preferable that the thickness is within the range of 0.03 mm to 0.3 mm plus the thickness of the disk used. If this gap exceeds the range of the disk thickness plus 0.3 mm, the effect of controlling the surface runout of the disk cannot be obtained sufficiently, and if there is no groove within the range of the disk thickness plus 0.03 mm, This is undesirable because the disc is held down by the protruding member, which tends to cause uneven rotation in the motor of the rotating device, and the recording and reproducing characteristics become unstable.

Magnetic disks can be of either single-sided or double-sided recording type.

The material of the protruding member is not particularly limited. A protrusion member made of any material such as plastic, metal, or fiber can be provided. The only requirement for the protrusion member is that the surface roughness Ra of the sliding surface with the magnetic disk is 0.01 to 10μ.
It is within the range of m.

[Example] Hereinafter, specific examples of the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a sectional view of a disk cartridge of the present invention, and FIG. 2 is a view taken along the line A--A in FIG.

In FIG. 1, a 5-inch diameter floppy disk 4 is rotatably housed in a cartridge case 1. As shown in FIG. On the upper and lower inner surfaces of the cartridge case 1, there are an outer ring plate 2 for regulating the disk surface runout on the outer circumference side of the floppy disk 4, and an inner circumferential ring plate 2 for regulating the disk surface deflection on the inner circumference side of the floppy disk 4. an outer ring plate 2 facing the side ring plate 3 at a predetermined position from the outermost circumference to the inner circumference of the disk magnetic surface;
An inner ring plate 3 is provided facing a predetermined position from the innermost circumference to the outer circumference of the disk magnetic surface. In this example, the surface roughness Ra of the outermost surface of the ring plate was 0.5 μm.

Further, when the upper jacket and the lower jacket of the cartridge case 1 are combined, the inner ring plate 3 of the outer ring plate 2 is provided at a predetermined position.
The width of each ring plate was set so that the vertical gap minus the thickness of the floppy disk 4 was less than 0.1 cm, and the width of each ring plate was about 2 l.

The ring plate used in this example was made of carbon on both the inner and outer circumferential sides.

The surface roughness Ra of the outermost surface of the ring plate is 0.005 μm.
A disk cartridge was produced in the same manner as in the above example except for the following.

A disk cartridge was produced in the same manner as in the above example except that the surface roughness Ra of the outermost surface of the ring plate was set to 50 μm.

Inside the disk cartridges prepared in the above Examples and Comparative Examples 1 and 2, a 5-inch diameter floppy disk (on a polyimide film substrate with a thickness of 50 μm, 0.
A medium in which a perpendicularly magnetized film made of a Co-Cr alloy with a thickness of 2 μm is formed, a Si thin film with a thickness of 0.02 μm is formed by sputtering, and a lubricant is applied) is rotatably housed in three types. A magnetic disk cartridge was manufactured.

Connect these to a commercially available 5-inch floppy disk drive (
FDD) to perform recording/playback tests and determine the output (dB
) was measured. Note that the output (dB) is based on Comparative Example 2 (
0...zero) and evaluated.

Moreover, the durability was evaluated by the path rotation (X100O) until the output (dB) decreased by 2 dB. The results are shown in Table 1 below.
The following is a summary.

Table 1- Merely providing a ring plate inside the case does not sufficiently improve the recording/reproducing characteristics and durability of the magnetic disk. Only by doing so can you obtain a perfect improvement effect.

[Effects of the Invention] As explained above, according to the present invention, in a magnetic disk housed in a disk cartridge having respective protrusion members provided opposite to predetermined portions of a rotating disk, surface roughness on the surface of the protrusion members can be improved. By controlling the hardness within a specific range, recording/reproducing characteristics and durability can be significantly improved, and a highly reliable magnetic disk can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the internal structure of a disk cartridge manufactured in an example of the present invention, and FIG.
The figure shows an AA arrow view of the disk cartridge in FIG. 1. 1... Cartridge case. 2...Outer ring plate. 3...Inner ring plate. 4...Floppy disk

Claims (2)

[Claims] (1) Consisting of a magnetic disk and a cartridge case in which the magnetic disk is rotatably housed, at least In a disk cartridge provided with a set of protruding members, the surface roughness Ra of the surface of the protruding members on the magnetic disk side is
A disc cartridge characterized in that the diameter is within the range of 0.01 μm to 10 μm. (2) The gap between the upper protruding member and the lower protruding member is 0.03 mm to 0.3 m depending on the thickness of the magnetic disk used.
Claim 1 characterized in that the value is within the range of adding the value of m.
Disc cartridge listed.