MAGNETIC TAPE AND MAGNETIC TAPE DEVICE

• US 20170372740A1
• Filed: 06/16/2017
• Published: 12/28/2017
• Est. Priority Date: 06/23/2016
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: OZAWA, Eiki, KANEKO, Tetsuya, KASADA, Norihito
• Granted Patent: US 10,510,368 B2
• Time in Patent Office: Days
• CPC Class Codes: G11B 5/584 for track following on tapes
• CPC Class Codes: G11B 5/70 on a base layer
• CPC Class Codes: G11B 5/708 characterised by addition of non-magnetic particles to the layer
• CPC Class Codes: G11B 5/71 characterised by the lubricant
• CPC Class Codes: G11B 5/73 Base layers , i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
• CPC Class Codes: G11B 5/733 characterised by the addition of non-magnetic particles base layers having a non-magnetic layer under a soft magnetic layer G11B5/736; magnetic recording media substrates G11B5/739
• CPC Class Codes: G11B 5/735 characterised by the back layer magnetic recording media substrates G11B5/739
• CPC Class Codes: G11B 5/78 Tape carriers

Abstract

Provided is a magnetic tape in which the total thickness is equal to or smaller than 5.30 μm, the magnetic layer includes a timing-based servo pattern, a magnetic layer surface Ra is equal to or smaller than 1.8 nm, the magnetic layer includes fatty acid ester, a full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer before performing vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 7.0 nm, a full width at half maximum of spacing distribution measured after performing the vacuum heating is greater than 0 nm and equal to or smaller than 7.0 nm, and a difference between a spacing measured after performing the vacuum heating and a spacing measured before performing the vacuum heating is greater than 0 nm and equal to or smaller than 8.0 nm.

Claims

1. A magnetic tape comprising:

a non-magnetic support; and

a magnetic layer including ferromagnetic powder and a binder on the non-magnetic support,

wherein a total thickness of the magnetic tape is equal to or smaller than 5.30 μ

m,

the magnetic layer includes a timing-based servo pattern,

a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm,

the magnetic layer includes fatty acid ester,

a full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer before performing vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 7.0 nm,

a full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 7.0 nm, and

a difference S_after−

S_before between a spacing S_after measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape and a spacing S_before measured by optical interferometry regarding the surface of the magnetic layer before performing the vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 8.0 nm.

2. The magnetic tape according to claim 1,

wherein the difference S_after−

S_before is greater than 0 nm and equal to or smaller than 5.0 nm.

3. The magnetic tape according to claim 1,

wherein the difference S_after−

S_before is 1.5 nm to 5.0 nm.

4. The magnetic tape according to claim 1,

wherein the full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer before performing vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 6.0 nm.

5. The magnetic tape according to claim 1,

wherein the full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 6.0 nm.

6. The magnetic tape according to claim 1,

wherein the magnetic layer includes a non-magnetic filler.

7. The magnetic tape according to claim 6,

wherein the non-magnetic filler is colloidal particles.

8. The magnetic tape according to claim 7,

wherein the colloidal particles are silica colloidal particles.

9. The magnetic tape according to claim 1,

wherein the center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.2 nm to 1.8 nm.

10. The magnetic tape according to claim 1,

wherein the total thickness of the magnetic tape is 3.00 μ

m to 5.30 μ

m.

11. The magnetic tape according to claim 1, further comprising:

a non-magnetic layer including non-magnetic powder and a binder, between the non-magnetic support and the magnetic layer.

12. The magnetic tape according to claim 1, further comprising:

a back coating layer including non-magnetic powder and a binder on a surface of the non-magnetic support opposite to the surface including the magnetic layer.

13. A magnetic tape device comprising:

a magnetic tape;

a magnetic head; and

a servo head, wherein

the magnetic tape is a magnetic tape comprising;

a non-magnetic support; and

a magnetic layer including ferromagnetic powder and a binder on the non-magnetic support,

wherein a total thickness of the magnetic tape is equal to or smaller than 5.30 μ

m,

the magnetic layer includes a timing-based servo pattern,

a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm,

the magnetic layer includes fatty acid ester,

a full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer before performing vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 7.0 nm,

a full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 7.0 nm, and

a difference S_after−

S_before between a spacing S_after measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape and a spacing S_before measured by optical interferometry regarding the surface of the magnetic layer before performing the vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 8.0 nm.

14. The magnetic tape device according to claim 13,

wherein the difference S_after−

S_before is greater than 0 nm and equal to or smaller than 5.0 nm.

15. The magnetic tape device according to claim 13,

wherein the difference S_after−

S_before is 1.5 nm to 5.0 nm.

16. The magnetic tape device according to claim 13,

wherein the full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer before performing vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 6.0 nm.

17. The magnetic tape device according to claim 13,

wherein the full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 6.0 nm.

18. The magnetic tape device according to claim 13,

wherein the center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.2 nm to 1.8 nm.

19. The magnetic tape device according to claim 13,

wherein the total thickness of the magnetic tape is 3.00 μ

m to 5.30 μ

m.