Magnetic tape including characterized magnetic layer and magnetic tape device

Patent metadata

Field	Value
Publication number	US-10510368-B2
Application number	US-201715624897-A
Country	US
Kind code	B2
Filing date	Jun 16, 2017
Priority date	Jun 23, 2016
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

A magnetic tape is provided in which the total thickness is less than or equal to 5.30 μm. The magnetic layer includes a timing-based servo pattern and also a fatty acid ester; and the magnetic layer surface Ra is less than or equal to 1.8 nm. 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 less than or equal to 7.0 nm, while the same value measured after performing the vacuum heating is greater than 0 nm and less than or equal to 7.0 nm, also. The 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 less than or equal to 8.0 nm.

First claim

What is claimed is:

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 μm,
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 μm to 5.30 μm.

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 μm,
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 μm to 5.30 μm.

Assignees

• Fujifilm Corp

Inventors

• Ozawa Eiki
• Kaneko Tetsuya
• Kasada Norihito

Classifications

• G11B5/70

  on a base layer · CPC title

• G11B5/73

  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 title

• G11B5/708

  characterised by addition of non-magnetic particles to the layer · CPC title

• G11B5/584

  for track following on tapes · CPC title

• G11B5/733

  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 title