IP Library Granted Patent US 11,087,793
Granted Patent B2
US 11,087,793 · App. 16/727,181 · Granted Aug 10, 2021

Magnetic tape with particular refractive index characteristics, magnetic tape cartridge, and magnetic tape apparatus

Inventor: Norihito Kasada (Minami-ashigara, JP)
Assignee: FUJIFILM Corporation
G11B5/7358G11B5/59688G11B5/70G11B5/706G11B5/70605G11B5/70689G11B23/107
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Quick Facts
Patent No.
US 11,087,793
App. No.
16/727,181
Granted
Aug 10, 2021
Kind
B2
Abstract

Provided are a magnetic tape including: a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which a total thickness of the magnetic tape is equal to or smaller than 5.30 μm, the magnetic layer has a servo pattern, a center line average surface roughness Ra measured on a surface of the magnetic layer is equal to or smaller than 1.8 nm, and an absolute value ΔN of a difference between a refractive index Nxy of the magnetic layer, measured in an in-plane direction and a refractive index Nz of the magnetic layer, measured in a thickness direction is 0.25 to 0.40, a magnetic tape cartridge and a magnetic tape apparatus including this magnetic tape, a magnetic tape cartridge and a magnetic tape apparatus including this magnetic tape.

Claims (62)

1. A magnetic tape comprising:

a non-magnetic support; and

a magnetic layer including ferromagnetic powder and a binding agent 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 has a servo pattern,

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

an absolute value ΔN of a difference between a refractive index Nxy of the magnetic layer, measured in an in-plane direction and a refractive index Nz of the magnetic layer, measured in a thickness direction is 0.25 to 0.40.

2. The magnetic tape according to claim 1 ,

wherein a difference Nxy−Nz between the refractive index Nxy and the refractive index Nz is 0.25 to 0.40.

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

a non-magnetic layer including non-magnetic powder and a binding agent between the non-magnetic support and the magnetic layer.

4. The magnetic tape according to claim 1 ,

wherein the total thickness of the magnetic tape is 3.00 μm to 5.30 μm.

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

a back coating layer including non-magnetic powder and a binding agent on a surface of the non-magnetic support opposite to a surface provided with the magnetic layer.

6. The magnetic tape according to claim 1 ,

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

7. The magnetic tape according to claim 1 ,

wherein the servo pattern is a timing-based servo pattern.

8. A magnetic tape cartridge comprising:

a magnetic tape, which comprises:

a non-magnetic support; and

a magnetic layer including ferromagnetic powder and a binding agent 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 has a servo pattern,

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

an absolute value ΔN of a difference between a refractive index Nxy of the magnetic layer, measured in an in-plane direction and a refractive index Nz of the magnetic layer, measured in a thickness direction is 0.25 to 0.40.

9. The magnetic tape cartridge according to claim 8 ,

wherein a difference Nxy−Nz between the refractive index Nxy and the refractive index Nz is 0.25 to 0.40.

10. The magnetic tape cartridge according to claim 8 ,

wherein the magnetic tape further comprises:

a non-magnetic layer including non-magnetic powder and a binding agent between the non-magnetic support and the magnetic layer.

11. The magnetic tape cartridge according to claim 8 ,

wherein the total thickness of the magnetic tape is 3.00 μm to 5.30 μm.

12. The magnetic tape cartridge according to claim 8 ,

wherein the magnetic tape further comprises:

a back coating layer including non-magnetic powder and a binding agent on a surface of the non-magnetic support opposite to a surface provided with the magnetic layer.

13. The magnetic tape cartridge according to claim 8 ,

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

14. The magnetic tape cartridge according to claim 8 ,

wherein the servo pattern is a timing-based servo pattern.

15. A magnetic tape apparatus comprising:

a magnetic head; and

a magnetic tape, which comprises:

a non-magnetic support; and

a magnetic layer including ferromagnetic powder and a binding agent 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 has a servo pattern,

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

an absolute value ΔN of a difference between a refractive index Nxy of the magnetic layer, measured in an in-plane direction and a refractive index Nz of the magnetic layer, measured in a thickness direction is 0.25 to 0.40.

16. The magnetic tape apparatus according to claim 15 ,

wherein a difference Nxy−Nz between the refractive index Nxy and the refractive index Nz is 0.25 to 0.40.

17. The magnetic tape apparatus according to claim 15 ,

wherein the magnetic tape further comprises:

a non-magnetic layer including non-magnetic powder and a binding agent between the non-magnetic support and the magnetic layer, and

a back coating layer including non-magnetic powder and a binding agent on a surface of the non-magnetic support opposite to a surface provided with the magnetic layer.

18. The magnetic tape apparatus according to claim 15 ,

wherein the total thickness of the magnetic tape is 3.00 μm to 5.30 μm.

19. The magnetic tape apparatus according to claim 15 ,

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

20. The magnetic tape apparatus according to claim 15 ,

wherein the servo pattern is a timing-based servo pattern.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 26, 2019
From: KASADA, NORIHITO
To: FUJIFILM CORPORATION
Reel/Frame 051371/0194 →
Priority Claims (1)
JP JP2018-246871 · Dec 28, 2018 · national
Continuity (1)
Related Publication 20200211592A1 · Jul 2, 2020