MAGNETIC TAPE AND MAGNETIC RECORDING AND REPRODUCING DEVICE

• US 20190103130A1
• Filed: 09/27/2018
• Published: 04/04/2019
• Est. Priority Date: 09/29/2017
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: KASADA, Norihito, OZAWA, Eiki
• Granted Patent: US 10,515,657 B2
• Time in Patent Office: Days
• CPC Class Codes: G11B 15/473 by controlling the speed of the heads
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• CPC Class Codes: G11B 5/00813 magnetic tapes
• CPC Class Codes: G11B 5/39 using magneto-resistive devices or effects
• CPC Class Codes: G11B 5/48 Disposition or mounting of heads or head supports relative to record carriers mounting of head within housing G11B5/105; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed driving of both record carriers and head G11B15/18; guiding record carriers G11B15/60; head selecting circuits G11B15/12
• CPC Class Codes: G11B 5/70678 Ferrites
• CPC Class Codes: G11B 5/735 characterised by the back layer magnetic recording media substrates G11B5/739
• CPC Class Codes: G11B 5/8404 manufacturing base layers

Abstract

Provided are a magnetic tape, in which a magnetic layer includes a ferromagnetic powder, a binding agent, and an oxide abrasive, ΔSFD in a longitudinal direction of the magnetic tape calculated by Expression 1, ΔSFD=SFD_{25° C.}−SFD_{−190° C.}, is equal to or smaller than 0.50, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050, and an average particle diameter of the oxide abrasive obtained from a secondary ion image obtained by irradiating the surface of the magnetic layer with a focused ion beam is 0.04 μm to 0.08 μm, and a magnetic recording and reproducing device including this magnetic tape.

Claims

1. A magnetic tape comprising:

a non-magnetic support; and

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

wherein Δ

SFD in a longitudinal direction of the magnetic tape calculated by Expression 1 is equal to or smaller than 0.50,

Δ

SFD=SFD<sub>25°

C.</sub>−

SFD<sub>−

190°

C.</sub> 

 

Expression 1,

in Expression 1, the SFD<sub>25°

C.</sub> is a switching field distribution SFD measured in the longitudinal direction of the magnetic tape at a temperature of 25°

C., and the SFD<sub>−

190°

C.</sub> is a switching field distribution SFD measured in the longitudinal direction of the magnetic tape at a temperature of −

190°

C.,

the magnetic layer includes an oxide abrasive,

a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050, and

an average particle diameter of the oxide abrasive obtained from a secondary ion image obtained by irradiating the surface of the magnetic layer with a focused ion beam is 0.04 μ

m to 0.08 μ

m.

2. The magnetic tape according to claim 1,

wherein the logarithmic decrement is 0.010 to 0.050.

3. The magnetic tape according to claim 1,

wherein the Δ

SFD is 0.03 to 0.50.

4. The magnetic tape according to claim 1,

wherein the ferromagnetic powder is a ferromagnetic hexagonal ferrite powder.

5. The magnetic tape according to claim 1,

wherein the oxide abrasive is an alumina powder.

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

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

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

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

8. A magnetic recording and reproducing device comprising:

a magnetic tape; and

a magnetic head,

wherein the magnetic tape is a magnetic tape comprising;

a non-magnetic support; and

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

wherein Δ

SFD in a longitudinal direction of the magnetic tape calculated by Expression 1 is equal to or smaller than 0.50,

Δ

SFD=SFD<sub>25°

C.</sub>−

SFD<sub>−

190°

C.</sub> 

 

Expression 1,

in Expression 1, the SFD<sub>25°

C.</sub> is a switching field distribution SFD measured in the longitudinal direction of the magnetic tape at a temperature of 25°

C., and the SFD<sub>−

190°

C.</sub> is a switching field distribution SFD measured in the longitudinal direction of the magnetic tape at a temperature of −

190°

C.,

the magnetic layer includes an oxide abrasive,

a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050, and

an average particle diameter of the oxide abrasive obtained from a secondary ion image obtained by irradiating the surface of the magnetic layer with a focused ion beam is 0.04 μ

m to 0.08 μ

m.

9. The magnetic recording and reproducing device according to claim 8,

wherein the magnetic head is a magnetic head including magnetoresistive element.

10. The magnetic recording and reproducing device according to claim 8,

wherein the logarithmic decrement is 0.010 to 0.050.

11. The magnetic recording and reproducing device according to claim 8,

wherein the Δ

SFD is 0.03 to 0.50.

12. The magnetic recording and reproducing device according to claim 8,

wherein the ferromagnetic powder is a ferromagnetic hexagonal ferrite powder.

13. The magnetic recording and reproducing device according to claim 8,

wherein the oxide abrasive is an alumina powder.

14. The magnetic recording and reproducing device according to claim 8,

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

15. The magnetic recording and reproducing device according to claim 8,

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