WO2000004544A1 - Magnetic disk - Google Patents

Magnetic disk Download PDF

Info

Publication number
WO2000004544A1
WO2000004544A1 PCT/JP1999/002964 JP9902964W WO0004544A1 WO 2000004544 A1 WO2000004544 A1 WO 2000004544A1 JP 9902964 W JP9902964 W JP 9902964W WO 0004544 A1 WO0004544 A1 WO 0004544A1
Authority
WO
WIPO (PCT)
Prior art keywords
recording medium
magnetic recording
magnetic
bonding
core member
Prior art date
Application number
PCT/JP1999/002964
Other languages
French (fr)
Inventor
Akira Mizuta
Original Assignee
Fuji Photo Film Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fuji Photo Film Co., Ltd. filed Critical Fuji Photo Film Co., Ltd.
Publication of WO2000004544A1 publication Critical patent/WO2000004544A1/en

Links

Classifications

    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B23/00Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
    • G11B23/0014Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture record carriers not specifically of filamentary or web form
    • G11B23/0021Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture record carriers not specifically of filamentary or web form discs
    • G11B23/0028Details
    • G11B23/0035Details means incorporated in the disc, e.g. hub, to enable its guiding, loading or driving

Definitions

  • This invention relates to a magnetic disk of disk-like shape to be encased in a magnetic disk cartridge or the like, particularly one constituted by fastening a center core member at the center of a large-capacity flexible magnetic recording medium.
  • a magnetic disk cartridge comprising a flat case accommodating a magnetic disk that is a flexible magnetic recording medium obtained by forming magnetic material layers on both sides of a flexible disk- shaped base material composed of polyester sheet or the like (called a "floppy disk”).
  • the magnetic disk is rotated within the case to enable magnetic heads to effect magnetic recording on the magnetic material layers. Owing to such advantages as ease of handling and low cost, this magnetic disk cartridge is used as a recording medium mainly for computers.
  • a center core member is provided at the center portion of the flexible magnetic recording medium in order to support the magnetic recording medium and define its center of rotation.
  • the center core member is engaged and held by a chuck provided at the tip of a rotating spindle of a drive- side rotating drive means so as transfer the rotational drive force.
  • the rotational speed of this magnetic disk must be increased in proportion as the recording capacity of the magnetic recording medium increases.
  • the heights of the rapidly rotating magnetic recording medium and the magnetic heads that conduct recording and reproduction (writing and reading) inherently must be strictly maintained in an appropriate relationship to ensure the desired recording and reproduction performance.
  • the magnetic recording medium is therefore preferably made easily flexible to enhance tracking performance in its relationship to the magnetic heads .
  • one method used to improve penetration performance is to increase the flexibility of the magnetic recording medium by, for example, narrowing the width of the fastening flange of the center core member so as to reduce the bonding area with the magnetic recording medium and thus lower the restriction that the center core member exerts on the inner peripheral portion of the magnetic recording medium.
  • the adhesive tends to protrude beyond the fastening flange owing to the small area for adhesive application.
  • the protruding adhesive is liable to cause trouble by sticking to the assembly jigs or to adhere to the recording region of the magnetic recording medium and affect the magnetic heads. This makes it necessary to avoid protrusion of adhesive from the fastening flange. As inspection for rejecting magnetic disks with protruding adhesive is difficult to conduct visually, product reliability may be degraded.
  • an object of the present invention is to provide a magnetic disk that improves penetration performance by narrowing the bonding region between the center core member and the magnetic recording medium, prevents protrusion of the adhesive and enables inspection for detecting such protrusion to be conducted satisfactorily.
  • the present invention provides a magnetic disk characterized in that it comprises a disk- shaped flexible magnetic recording medium and a center core member having a fastening flange fastened to the center portion of the magnetic recording medium, the fastening flange of the center core member being formed to have a flat surface portion for bonding to the magnetic recording medium and an outer peripheral inclined portion produced by bending the outer periphery thereof away from a surface of the magnetic recording medium.
  • the angle of inclination of the outer peripheral inclined portion of the fastening flange is preferably in the range of 1-10 degrees.
  • the fastening flange of the center core member for bonding with the inner peripheral portion of the magnetic recording medium is formed with the flat surface portion for bonding and with the outer peripheral inclined portion produced by bending the outer periphery thereof away from the surface of the magnetic recording medium, the bonding region between the magnetic recording medium and the center core member is narrowed to lower the restriction that the bonding exerts on the magnetic recording medium, thereby increasing the flexibility of magnetic recording medium. As the positional relationship with the magnetic heads can therefore be maintained, the penetration performance is enhanced to enable excellent recording/reproduction performance.
  • Figure 1 is an exploded perspective view of a magnetic disk that is an embodiment of the present invention.
  • Figure 2 is an enlarged view of an essential portion of the magnetic disk.
  • Figure 3 is a perspective view showing inspection in progress .
  • Figure 1 is an exploded perspective view of a magnetic disk that is an embodiment of the present invention and Figure 2 is an enlarged view of an essential portion.
  • a magnetic disk is composed of a disk-shaped flexible magnetic recording medium 2 and a center core member 3 for rotational driving that is fastened to the center portion of the magnetic recording medium 2.
  • the magnetic recording medium 2 is made of a flexible base material such as polyethylene terephthalate (PET) that is formed on its opposite sides with magnetic material layers. It is disk-like with a center hole 2d. The annular region thereof between an outer peripheral portion and an inner peripheral portion constitutes a recording region 2a. The inner and outer edge portions of the recording region 2a are non-recording regions 2b and 2c.
  • PET polyethylene terephthalate
  • the center core member 3 is produced by punching a prescribed shape from a stock metal plate of stainless steel or other ferromagnetic material, followed by press-forming. It is constituted of an engaging portion 4 having a disk- shaped bottom surface, a fastening flange 5 extending brimlike from the upper outer periphery, and a upright cylindrical wall-like connecting portion 6 that connects the outer edge of the engaging portion 4 and the inner edge of the fastening flange 5.
  • the engaging portion 4 is provided with a center hole portion 4a that opens at the rotational center and a drive pin hole portion 4b that opens at a location outward of the center hole portion 4a. It is engaged and rotated by a magnetic engaging portion of a rotating spindle constituting the drive-side rotating drive means (not shown).
  • the inner peripheral side portion of the fastening flange 5 is formed as a flat surface portion for bonding 5a lying parallel to the engaging portion 4 (perpendicular to the rotational axis).
  • the flat surface portion for bonding 5a is attached to the non-recording region 2b at the inner peripheral portion of the magnetic recording medium 2 by adhesive 7.
  • an outer peripheral inclined portion 5b bent away from the surface of the magnetic recording medium 2. The angle of inclination of the outer peripheral inclined portion 5b is set to around 1-10 degrees.
  • the magnetic recording medium 2 and the center core member 3 are assembled by placing the magnetic recording medium 2 flat on a jig with its center aligned, applying a prescribed amount of adhesive 7 to prescribed locations of the undersurface of the flat surface portion for bonding 5a of the fastening flange 5, holding the fastening flange 5 over the magnetic recording medium 2 using a conveyor jig, lowering the fastening flange 5 onto the magnetic recording medium 2 while aligning their centers, and pressing the flat surface portion for bonding 5a of the fastening flange 5 onto the inner peripheral portion of the magnetic recording medium 2 to effect bonding by the adhesive 7.
  • the protruding adhesive 7 causes no trouble and can be easily detected by inspection using an optical sensor or the like to enable rejection of defective products.
  • Figure 3 shows an example of such inspection in progress.
  • a portion of the adhesive 7 applied to the flat surface portion for bonding 5a of the fastening flange 5 of the center core member 3 has oozed to the outer peripheral inclined portion 5b, its presence can be easily found by using an optical sensor 10 to inspect the outer peripheral inclined portion 5b as it is being rotated and detecting the protruding adhesive 7a from variation in the amount of reflected light.
  • the outer diameter of the connecting portion 6 of the center core member 3 is set smaller than the diameter of the center hole 2d of the magnetic recording medium 2 and the outer diameter of the fastening flange 5 is set smaller than the outer diameter of the non-recording region 2b of the magnetic recording medium 2.
  • the connecting portion 6 is formed to an outer diameter of 25mm, the flat surface portion for bonding 5a to an outer diameter of 27mm, and outer peripheral inclined portion 5b to an outer diameter of 29mm.
  • the magnetic disk is, for example, encased to be capable of rotation in a flat case constituted by bonding together upper and lower shells made of synthetic resin.
  • the case is formed with openings for insertion of magnetic heads and the center portion of the lower shell thereof is formed with a circular hub hole of a size allowing exposure of the engaging portion of the center core member therethrough.

Landscapes

  • Holding Or Fastening Of Disk On Rotational Shaft (AREA)
  • Manufacturing Of Magnetic Record Carriers (AREA)

Abstract

The bonding area between the magnetic recording medium and the center core member of a magnetic disk is narrowed while also eliminating the effect of protruding adhesive, thereby improving reliability. The magnetic disk comprises a disk-shaped flexible magnetic recording medium (2) and a center core member (3) having a fastening flange fastened to the center portion of the magnetic recording medium, and the fastening flange is formed to have a flat surface portion (5a) for bonding to the magnetic recording medium and an outer peripheral inclined portion (5b) produced by bending the outer periphery thereof away from a surface of the magnetic recording medium.

Description

DESCRIPTION MAGNETIC DISK Field of the Invention This invention relates to a magnetic disk of disk-like shape to be encased in a magnetic disk cartridge or the like, particularly one constituted by fastening a center core member at the center of a large-capacity flexible magnetic recording medium.
Background of the Invention There has long been available a magnetic disk cartridge comprising a flat case accommodating a magnetic disk that is a flexible magnetic recording medium obtained by forming magnetic material layers on both sides of a flexible disk- shaped base material composed of polyester sheet or the like (called a "floppy disk"). The magnetic disk is rotated within the case to enable magnetic heads to effect magnetic recording on the magnetic material layers. Owing to such advantages as ease of handling and low cost, this magnetic disk cartridge is used as a recording medium mainly for computers.
A center core member is provided at the center portion of the flexible magnetic recording medium in order to support the magnetic recording medium and define its center of rotation. The center core member is engaged and held by a chuck provided at the tip of a rotating spindle of a drive- side rotating drive means so as transfer the rotational drive force.
In order to secure the required data transfer rate, the rotational speed of this magnetic disk must be increased in proportion as the recording capacity of the magnetic recording medium increases. In addition, the heights of the rapidly rotating magnetic recording medium and the magnetic heads that conduct recording and reproduction (writing and reading) inherently must be strictly maintained in an appropriate relationship to ensure the desired recording and reproduction performance.
Strict maintenance of the positional relationship between the magnetic recording medium and the magnetic heads is difficult however because the magnetic recording medium is flexible and tends to experience surface undulation during rotation. When the recording density is high, moreover, the penetration performance, which enables tracking even if the magnetic recording medium position shifts relative to the magnetic heads, decreases in breadth. The magnetic recording medium is therefore preferably made easily flexible to enhance tracking performance in its relationship to the magnetic heads .
In light of this, one method used to improve penetration performance is to increase the flexibility of the magnetic recording medium by, for example, narrowing the width of the fastening flange of the center core member so as to reduce the bonding area with the magnetic recording medium and thus lower the restriction that the center core member exerts on the inner peripheral portion of the magnetic recording medium.
When the outer diameter of the fastening flange of the center core member is decreased so as to reduce its bonding width with the magnetic recording medium, however, assembly performance is essentially degraded and good adhesion cannot be obtained because the region of bonding of the magnetic recording medium by an adhesive becomes small.
Specifically, the adhesive tends to protrude beyond the fastening flange owing to the small area for adhesive application. The protruding adhesive is liable to cause trouble by sticking to the assembly jigs or to adhere to the recording region of the magnetic recording medium and affect the magnetic heads. This makes it necessary to avoid protrusion of adhesive from the fastening flange. As inspection for rejecting magnetic disks with protruding adhesive is difficult to conduct visually, product reliability may be degraded.
In view of the foregoing circumstances, an object of the present invention is to provide a magnetic disk that improves penetration performance by narrowing the bonding region between the center core member and the magnetic recording medium, prevents protrusion of the adhesive and enables inspection for detecting such protrusion to be conducted satisfactorily.
Summary of the Invention For achieving this object, the present invention provides a magnetic disk characterized in that it comprises a disk- shaped flexible magnetic recording medium and a center core member having a fastening flange fastened to the center portion of the magnetic recording medium, the fastening flange of the center core member being formed to have a flat surface portion for bonding to the magnetic recording medium and an outer peripheral inclined portion produced by bending the outer periphery thereof away from a surface of the magnetic recording medium. The angle of inclination of the outer peripheral inclined portion of the fastening flange is preferably in the range of 1-10 degrees.
In this magnetic disk according to the present invention, since the fastening flange of the center core member for bonding with the inner peripheral portion of the magnetic recording medium is formed with the flat surface portion for bonding and with the outer peripheral inclined portion produced by bending the outer periphery thereof away from the surface of the magnetic recording medium, the bonding region between the magnetic recording medium and the center core member is narrowed to lower the restriction that the bonding exerts on the magnetic recording medium, thereby increasing the flexibility of magnetic recording medium. As the positional relationship with the magnetic heads can therefore be maintained, the penetration performance is enhanced to enable excellent recording/reproduction performance. Moreover, even if adhesive should protrude to the outer peripheral inclined portion from the flat surface portion for bonding of the fastening flange, the protruding adhesive will be held within the outer peripheral inclined portion and be prevented from protruding to the exterior. In addition, since inspection for protrusion of adhesive to the outer peripheral inclined portion can be conducted with ease, defective products can be easily identified for rejection. Product reliability can therefore be improved.
Brief Description of the Drawings Figure 1 is an exploded perspective view of a magnetic disk that is an embodiment of the present invention.
Figure 2 is an enlarged view of an essential portion of the magnetic disk.
Figure 3 is a perspective view showing inspection in progress .
Preferred Embodiment of the Invention The invention will now be explained in detail based on an embodiment shown in the drawings. Figure 1 is an exploded perspective view of a magnetic disk that is an embodiment of the present invention and Figure 2 is an enlarged view of an essential portion.
A magnetic disk is composed of a disk-shaped flexible magnetic recording medium 2 and a center core member 3 for rotational driving that is fastened to the center portion of the magnetic recording medium 2.
The magnetic recording medium 2 is made of a flexible base material such as polyethylene terephthalate (PET) that is formed on its opposite sides with magnetic material layers. It is disk-like with a center hole 2d. The annular region thereof between an outer peripheral portion and an inner peripheral portion constitutes a recording region 2a. The inner and outer edge portions of the recording region 2a are non-recording regions 2b and 2c.
The center core member 3 is produced by punching a prescribed shape from a stock metal plate of stainless steel or other ferromagnetic material, followed by press-forming. It is constituted of an engaging portion 4 having a disk- shaped bottom surface, a fastening flange 5 extending brimlike from the upper outer periphery, and a upright cylindrical wall-like connecting portion 6 that connects the outer edge of the engaging portion 4 and the inner edge of the fastening flange 5. The engaging portion 4 is provided with a center hole portion 4a that opens at the rotational center and a drive pin hole portion 4b that opens at a location outward of the center hole portion 4a. It is engaged and rotated by a magnetic engaging portion of a rotating spindle constituting the drive-side rotating drive means (not shown).
The inner peripheral side portion of the fastening flange 5 is formed as a flat surface portion for bonding 5a lying parallel to the engaging portion 4 (perpendicular to the rotational axis). The flat surface portion for bonding 5a is attached to the non-recording region 2b at the inner peripheral portion of the magnetic recording medium 2 by adhesive 7. At the outer peripheral portion of the flat surface portion for bonding 5a is formed an outer peripheral inclined portion 5b bent away from the surface of the magnetic recording medium 2. The angle of inclination of the outer peripheral inclined portion 5b is set to around 1-10 degrees.
The magnetic recording medium 2 and the center core member 3 are assembled by placing the magnetic recording medium 2 flat on a jig with its center aligned, applying a prescribed amount of adhesive 7 to prescribed locations of the undersurface of the flat surface portion for bonding 5a of the fastening flange 5, holding the fastening flange 5 over the magnetic recording medium 2 using a conveyor jig, lowering the fastening flange 5 onto the magnetic recording medium 2 while aligning their centers, and pressing the flat surface portion for bonding 5a of the fastening flange 5 onto the inner peripheral portion of the magnetic recording medium 2 to effect bonding by the adhesive 7.
In this embodiment, even if adhesive 7 protrudes from the flat surface portion for bonding 5a to the outer peripheral inclined portion 5b when the adhesive 7 is applied to the flat surface portion for bonding 5a of the fastening flange 5 or during bonding to the magnetic recording medium 2 under pressure, the protruding adhesive 7 causes no trouble and can be easily detected by inspection using an optical sensor or the like to enable rejection of defective products.
Figure 3 shows an example of such inspection in progress. When a portion of the adhesive 7 applied to the flat surface portion for bonding 5a of the fastening flange 5 of the center core member 3 has oozed to the outer peripheral inclined portion 5b, its presence can be easily found by using an optical sensor 10 to inspect the outer peripheral inclined portion 5b as it is being rotated and detecting the protruding adhesive 7a from variation in the amount of reflected light.
The outer diameter of the connecting portion 6 of the center core member 3 is set smaller than the diameter of the center hole 2d of the magnetic recording medium 2 and the outer diameter of the fastening flange 5 is set smaller than the outer diameter of the non-recording region 2b of the magnetic recording medium 2. For instance, the connecting portion 6 is formed to an outer diameter of 25mm, the flat surface portion for bonding 5a to an outer diameter of 27mm, and outer peripheral inclined portion 5b to an outer diameter of 29mm.
The magnetic disk is, for example, encased to be capable of rotation in a flat case constituted by bonding together upper and lower shells made of synthetic resin. The case is formed with openings for insertion of magnetic heads and the center portion of the lower shell thereof is formed with a circular hub hole of a size allowing exposure of the engaging portion of the center core member therethrough.

Claims

1. A magnetic disk comprising a disk-shaped flexible magnetic recording medium and a center core member having a fastening flange fastened to the center portion of the magnetic recording medium, the magnetic disk being characterized in that the fastening flange of the center core member is formed to have a flat surface portion for bonding to the magnetic recording medium and an outer peripheral inclined portion produced by bending the outer periphery thereof away from a surface of the magnetic recording medium.
2. The magnetic disk of claim 1, characterized in that the angle of inclination of the outer peripheral inclined portion is 1-10 degrees.
PCT/JP1999/002964 1998-07-17 1999-06-03 Magnetic disk WO2000004544A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP10202495A JP2000036167A (en) 1998-07-17 1998-07-17 Magnetic disk
JP10/202495 1998-07-17

Publications (1)

Publication Number Publication Date
WO2000004544A1 true WO2000004544A1 (en) 2000-01-27

Family

ID=16458445

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP1999/002964 WO2000004544A1 (en) 1998-07-17 1999-06-03 Magnetic disk

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WO (1) WO2000004544A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5260188B2 (en) * 2008-08-27 2013-08-14 富士フイルム株式会社 Hard disk inspection apparatus and method, and program
JP6633858B2 (en) * 2015-07-30 2020-01-22 三ツ星ベルト株式会社 Waterproofing method and waterproofing structure for concrete substrate

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5391414A (en) * 1992-09-21 1995-02-21 Minnesota Mining And Manufacturing Company Diskettes having crosslinked adhesive bond to hub
JPH07147072A (en) * 1993-11-24 1995-06-06 Mitsubishi Chem Corp Hub for optical disk
JPH08138340A (en) * 1994-11-11 1996-05-31 Sony Corp Magnetic disc

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5391414A (en) * 1992-09-21 1995-02-21 Minnesota Mining And Manufacturing Company Diskettes having crosslinked adhesive bond to hub
JPH07147072A (en) * 1993-11-24 1995-06-06 Mitsubishi Chem Corp Hub for optical disk
JPH08138340A (en) * 1994-11-11 1996-05-31 Sony Corp Magnetic disc

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 95, no. 009 31 October 1995 (1995-10-31) *
PATENT ABSTRACTS OF JAPAN vol. 96, no. 009 3 September 1996 (1996-09-03) *

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