Magnetic tape, magnetic tape cartridge, and magnetic tape apparatus

Patent metadata

Field	Value
Publication number	US-11423932-B2
Application number	US-202117399241-A
Country	US
Kind code	B2
Filing date	Aug 11, 2021
Priority date	Jan 31, 2019
Publication date	Aug 23, 2022
Grant date	Aug 23, 2022

Abstract

The magnetic tape includes a non-magnetic support; and a magnetic layer in which the magnetic layer has a timing-based servo pattern, an edge shape of the timing-based servo pattern, specified by magnetic force microscopy is a shape in which a difference between a value L99.9 of a cumulative distribution function of 99.9% and a value L0.1 of a cumulative distribution function of 0.1% in a position deviation width from an ideal shape of the magnetic tape in a longitudinal direction is 180 nm or less, and a difference between a spacing Safter measured on a surface of the magnetic layer by an optical interferometry after methyl-ethyl-ketone cleaning and a spacing Sbefore measured on the surface of the magnetic layer by an optical interferometry before methyl-ethyl-ketone cleaning is greater than 0 nm and 15.0 nm or less.

First claim

What is claimed is:

1. A magnetic tape comprising:
a non-magnetic support;
a magnetic layer including ferromagnetic powder;
a non-magnetic layer including non-magnetic powder between the non-magnetic support and the magnetic layer; and
a back coating layer on a surface side of the non-magnetic support opposite to a surface side provided with the magnetic layer,
wherein the magnetic layer has a timing-based servo pattern,
wherein the ferromagnetic powder is at least one ferromagnetic powder selected from the group consisting of hexagonal ferrite powder and ε-iron oxide powder
wherein an edge shape of the timing-based servo pattern, specified by magnetic force microscopy is a shape in which a difference L 99.9 −L 0.1 between a value L 99.9 of a cumulative distribution function of 99.9% and a value L 0.1 of a cumulative distribution function of 0.1% in a position deviation width from an ideal shape of the magnetic tape in a longitudinal direction is 180 nm or less, and
wherein a difference S after −S before between a spacing S after measured on a surface of the magnetic layer by an optical interferometry after methyl-ethyl-ketone cleaning and a spacing S before measured on the surface of the magnetic layer by an optical interferometry before methyl-ethyl-ketone cleaning is greater than 0 nm and 15.0 nm or less.

2. The magnetic tape according to claim 1 ,
wherein the difference S after −S before is 2.0 nm or more and 15.0 nm or less.

3. The magnetic tape according to claim 1 ,
wherein the difference S after −S before is 3.0 nm or more and 12.0 nm or less.

4. The magnetic tape according to claim 1 ,
wherein the timing-based servo pattern is a linear servo pattern which continuously extends from one side of the magnetic tape in a width direction to the other side thereof and is inclined at an angle α with respect to the width direction, and
wherein the ideal shape is a linear shape extending in a direction of the angle α.

5. The magnetic tape according to claim 1 ,
wherein the difference L 99.9 −L 0.1 is 100 nm or more and 180 nm or less.

6. The magnetic tape according to claim 1 ,
wherein a thickness of the magnetic layer is 10 nm to 70 nm.

7. The magnetic tape according to claim 1 ,
wherein a thickness of the non-magnetic layer is 100 nm to 800 nm.

8. The magnetic tape according to claim 1 ,
wherein a thickness of the back coating layer is 0.1 μm to 0.4 μm.

9. The magnetic tape according to claim 1 ,
wherein an average particle size of the ferromagnetic powder is 25 nm or less.

10. The magnetic tape according to claim 1 ,
wherein the ferromagnetic powder is vertically orientated.

11. A magnetic tape cartridge comprising:
the magnetic tape according to claim 1 .

12. The magnetic tape cartridge according to claim 11 ,
wherein the difference S after −S before is 2.0 nm or more and 15.0 nm or less.

13. The magnetic tape cartridge according to claim 11 ,
wherein the difference S after −S before is 3.0 nm or more and 12.0 nm or less.

14. The magnetic tape cartridge according to claim 11 ,
wherein the timing-based servo pattern is a linear servo pattern which continuously extends from one side of the magnetic tape in a width direction to the other side thereof and is inclined at an angle α with respect to the width direction, and
wherein the ideal shape is a linear shape extending in a direction of the angle α.

15. The magnetic tape cartridge according to claim 11 ,
wherein the difference L 99.9 −L 0.1 is 100 nm or more and 180 nm or less.

16. The magnetic tape cartridge according to claim 11 ,
wherein the ferromagnetic powder is vertically orientated.

17. A magnetic tape apparatus comprising:
a magnetic tape;
a reading element unit; and
an extraction unit,
wherein the magnetic tape is the magnetic tape according to claim 1 ,
wherein the reading element unit includes a plurality of reading elements each of which reads data from a specific track region including a reading target track in a track region included in the magnetic tape, and
wherein the extraction unit performs a waveform equalization process with respect to each reading result for each reading element, to extract, from the reading result, data derived from the reading target track.

18. The magnetic tape apparatus according to claim 17 ,
wherein the difference S after −S before is 3.0 nm or more and 12.0 nm or less.

19. The magnetic tape apparatus according to claim 17 ,
wherein the timing-based servo pattern is a linear servo pattern which continuously extends from one side of the magnetic tape in a width direction to the other side thereof and is inclined at an angle α with respect to the width direction, and
wherein the ideal shape is a linear shape extending in a direction of the angle α.

20. The magnetic tape apparatus according to claim 17 ,
wherein the difference L 99.9 −L 0.1 is 100 nm or more and 180 nm or less.

Assignees

• Fujifilm Corp

Inventors

• Ozawa Eiki
• Kasada Norihito
• Musha Atsushi

Classifications

• G11B23/502

  of tape carriers · CPC title

• G01B11/0675

  using interferometry · CPC title

• G11B5/702

  characterised by the bonding agent · CPC title

• G11B5/70678

  Ferrites · CPC title

• G11B5/735

  characterised by the back layer {(magnetic recording media substrates G11B5/739)} · CPC title