Magnetic disk cartridge

• US 20060098342A1
• Filed: 09/09/2005
• Published: 05/11/2006
• Est. Priority Date: 09/09/2004
• Status: Abandoned Application

• Current Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Saito, Shinji, Matsumoto, Ayako, Noguchi, Hitoshi
• Application Number:
  US11/221,731
• Publication Number:
  US 20060098342A1
• Time in Patent Office: Days
• US Class Current: 360/133
• CPC Class Codes: G11B 23/0308 Shutters G11B23/0317 takes precedence
• CPC Class Codes: G11B 23/0316 Constructional details, e.g. shape
• CPC Class Codes: G11B 23/0321 rigid cartridges for single discs

Abstract

A magnetic disk cartridge, which holds therein a magnetic disk with recording density and has a liner composed of polyethylene terephthalate fibers, is provided which achieves a good dust-removal effect by the liner without flawing the magnetic disk and without increasing the rotary torque of the magnetic disk. A magnetic layer of the magnetic disk is formed such that the magnetic layer contains diamond particles which have an average particle size satisfying a relationship “b−0.05≦a≦b+0.1” at 1% to 10% by weight with respect to the ferromagnetic material, where “a” represents the average particle size of the diamond particles in units of μm and “b” represents a thickness of the magnetic layer in units of μm. The fibers of the liner are selected from the fibers whose fiber diameter varies in its length direction.

Claims

1. A magnetic disk cartridge comprising:

a magnetic disk comprising a discoid nonmagnetic substrate and a magnetic layer that is formed of a ferromagnetic material and disposed on at least one surface of the nonmagnetic substrate, the magnetic disk having a surface recording density of at least 158.7 Mbit/cm²;

a casing which rotatably holds therein the magnetic disk;

a liner, which is composed of polyethylene terephthalate fibers and attached to a surface of the casing that faces the magnetic disk, for removing contaminants on the surface of the magnetic disk,

wherein the magnetic layer containing diamond particles at 1% to 10% by weight with respect to the ferromagnetic material, the diamond particles having an average particle size satisfying a formula given by;

b−

0.05≦

a≦

+0.1

where “

a”

represents the average particle size of the diamond particles in units of μ

m and “

b”

represents a thickness of the magnetic layet in units of μ

m, and

wherein a fiber diameter of the fibers of the liner varies along a length direction of the fibers.

2. The magnetic disk cartridge as defined in claim 1, wherein a minimum fiber diameter of the fibers of the liner is within the range of 5% to 60% of a maximum fiber diameter of the fibers.

3. The magnetic disk cartridge as defined in claim 1, wherein the ferromagnetic material is ferromagnetic hexagonal ferrite powder.

4. The magnetic disk cartridge as defined in claim 2, wherein the ferromagnetic material is ferromagnetic hexagonal ferrite powder.

5. The magnetic disk cartridge as defined in claim 1, wherein the average particle size of the diamond particles is in the range of 0.01 to 2 μ

m.

6. The magnetic disk cartridge as defined in claim 1, wherein the surface recording density of the magnetic disk is at least 793.5 Mbit/cm².

7. The magnetic disk cartridge as defined in claim 1, wherein the magnetic disk has a track density of not less than 10 Ktpi.

8. The magnetic disk cartridge as defined in claim 1, wherein the magnetic disk has a track recording density of not less than 100 Kbpi.

9. The magnetic disk cartridge as defined in claim 1, wherein the magnetic disk further comprises a lower layer which is formed on the substrate and substantially nonmagnetic, and an upper layer constituting a magnetic layer which is formed on the lower layer.

10. The magnetic disk cartridge as defined in claim 1, wherein the substrate is flexible.

11. The magnetic disk cartridge as defined in claim 1, wherein the substrate has a thickness in the range of 2 to 100 μ

m.

12. The magnetic disk cartridge as defined in claim 1, wherein the substrate has a thickness in the range of 2 to 80 μ

m.

13. The magnetic disk cartridge at defined in claim 1, wherein the substrate is made of polyethylene terephthalate.

14. The magnetic disk cartridge as defined in claim 1, wherein the substrate is made of polyethylene naphthalate.

15. The magnetic disk cartridge as defined in claim 1, wherein the magnetic disk is designed so that data recorded thereon is reproduced by an MR head of a disk drive.

16. The magnetic disk cartridge as defined in claim 1, wherein the magnetic disk is designed so that data recorded thereon is reproduced by a GMR head of a disk drive.

17. The magnetic disk cartridge as defined in claim 1, wherein the magnetic disk is designed so that data recorded thereon is reproduced by a TMR head of a disk drive.