Magnetic recording medium and magnetic recording and reproducing device

Patent metadata

Field	Value
Publication number	US-2020090694-A1
Application number	US-201916569103-A
Country	US
Kind code	A1
Filing date	Sep 12, 2019
Priority date	Sep 14, 2018
Publication date	Mar 19, 2020
Grant date	—

Abstract

The magnetic recording medium includes a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, in which a difference (S0.5−S13.5) between a spacing S0.5 measured by optical interferometry regarding a surface of the magnetic layer under a pressing force of 0.5 atm after n-hexane cleaning and a spacing S13.5 measured by optical interferometry regarding the surface of the magnetic layer under a pressing force of 13.5 atm after n-hexane cleaning is equal to or smaller than 3.0 nm, and a magnetic recording and reproducing device including this magnetic recording medium.

First claim

What is claimed is:

1 . A magnetic recording medium comprising:
a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, wherein a difference S 0.5 −S 13.5 between a spacing S 0.5 measured by optical interferometry regarding a surface of the magnetic layer under a pressing force of 0.5 atm after n-hexane cleaning and a spacing S 13.5 measured by optical interferometry regarding the surface of the magnetic layer under a pressing force of 13.5 atm after n-hexane cleaning is equal to or smaller than 3.0 nm.

2 . The magnetic recording medium according to claim 1 ,
wherein the difference is 1.5 nm to 3.0 nm.

3 . The magnetic recording medium according to claim 1 ,
wherein the S 0.5 is 5.0 to 50.0 nm.

4 . The magnetic recording medium according to claim 1 ,
wherein the magnetic layer includes inorganic oxide particles.

5 . The magnetic recording medium according to claim 4 ,
wherein the inorganic oxide particles are composite particles of inorganic oxide and a polymer.

6 . The magnetic recording medium according to claim 1 ,
wherein the magnetic layer includes one or more kinds of lubricant selected from the group consisting of fatty acid, fatty acid ester, and fatty acid amide.

7 . The magnetic recording medium 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.

8 . The magnetic recording medium 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.

9 . The magnetic recording medium according to claim 1 ,
wherein the magnetic recording medium is a magnetic tape.

10 . The magnetic recording medium according to claim 9 ,
wherein the non-magnetic support is an aromatic polyester support, and a Young's modulus of the aromatic polyester support is equal to or greater than 3000 N/mm 2 in a longitudinal direction and equal to or greater than 4000 N/mm 2 in a width direction.

11 . The magnetic recording medium according to claim 1 ,
wherein the ferromagnetic powder is a hexagonal barium ferrite powder.

12 . The magnetic recording medium according to claim 1 ,
wherein the ferromagnetic powder is a hexagonal strontium ferrite powder.

13 . The magnetic recording medium according to claim 1 ,
wherein the ferromagnetic powder is an ε-iron oxide powder.

14 . A magnetic recording and reproducing device comprising:
the magnetic recording medium according to claim 1 ; and a magnetic head.

Assignees

• Fujifilm Corp

Inventors

• Sano Naoki
• Kurokawa Takuto
• Kasada Norihito
• Ozawa Eiki

Classifications

• G11B5/73927 Primary

  Polyester substrates, e.g. polyethylene terephthalate · CPC title

• G11B5/845

  in a magnetic field · CPC title

• G11B5/708

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

• G11B5/66 Primary

  the record carriers consisting of several layers · CPC title

• G11B5/70 Primary

  on a base layer · CPC title