IP Library › Granted Patent US 12,190,918
Granted Patent B2
US 12,190,918 · App. 17/338,694 · Granted Jan 7, 2025

Magnetic recording and reproducing device

Inventors: So Matsuyama (Kanagawa, JP); Norihito Kasada (Kanagawa, JP); Takuto Kurokawa (Kanagawa, JP)
Assignee: FUJIFILM Corporation
G11B5/3116G11B5/70678G11B5/714G11B5/7356
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Quick Facts
Patent No.
US 12,190,918
App. No.
17/338,694
Granted
Jan 7, 2025
Kind
B2
Abstract

The magnetic recording and reproducing device includes a magnetic recording medium, a recording element, and a reproducing element. The recording element is an inductive recording element having a first magnetic pole which generates a magnetic field, and a second magnetic pole which is spaced apart from the first magnetic pole with a write gap interposed therebetween, a tip width of the first magnetic pole is substantially the same as a tip width of the second magnetic pole, and a reproducing element width of the reproducing element is 0.2 μm or greater and less than 0.5 μm. In the magnetic recording medium, the number of recesses, which are present in a surface of the magnetic layer and have an equivalent circle diameter of 0.10 μm or greater and less than 0.20 μm, is 100 to 2,000 per area of 40 μm×40 μm.

Claims (30)

1. A magnetic recording and reproducing device comprising:

a magnetic recording medium;

a recording element; and

a reproducing element,

wherein the recording element is an inductive recording element having a first magnetic pole which generates a magnetic field, and a second magnetic pole which is spaced apart from the first magnetic pole with a write gap interposed therebetween,

a tip width of the first magnetic pole is substantially the same as a tip width of the second magnetic pole,

a reproducing element width of the reproducing element is 0.2 μm or greater and less than 0.5 μm,

the magnetic recording medium has a non-magnetic support, and a magnetic layer containing a ferromagnetic powder, and

a number of recesses, which are present in a surface of the magnetic layer and have an equivalent circle diameter of 0.10 μm or greater and less than 0.20 μm, is 100 to 2,000 per area of 40 μm×40 μm.

2. The magnetic recording and reproducing device according to claim 1 , wherein a number of bright regions having an equivalent circle diameter of 50 nm or greater and less than 100 nm is 7,000 to 25,000 in a binarized image of a secondary electron image obtained by imaging the surface of the magnetic layer with a scanning electron microscope at an acceleration voltage of 5 kV.

3. The magnetic recording and reproducing device according to claim 1 ,

wherein a total thickness of the magnetic recording medium is 5.2 μm or less.

4. The magnetic recording and reproducing device according to claim 2 ,

wherein a total thickness of the magnetic recording medium is 5.2 μm or less.

5. The magnetic recording and reproducing device according to claim 1 ,

wherein the magnetic recording medium further has a non-magnetic layer which contains a non-magnetic powder and is provided between the non-magnetic support and the magnetic layer.

6. The magnetic recording and reproducing device according to claim 1 ,

wherein the magnetic recording medium further has a back coating layer which contains a non-magnetic powder and is provided on a surface side of the non-magnetic support opposite to a surface side on which the magnetic layer is provided.

7. The magnetic recording and reproducing device according to claim 6 ,

wherein the non-magnetic powder of the back coating layer includes carbon black.

8. The magnetic recording and reproducing device according to claim 1 ,

wherein the ferromagnetic powder is a hexagonal barium ferrite powder.

9. The magnetic recording and reproducing device according to claim 1 ,

wherein the ferromagnetic powder is a hexagonal strontium ferrite powder.

10. The magnetic recording and reproducing device according to claim 1 ,

wherein the ferromagnetic powder is an ε-iron oxide powder.

11. The magnetic recording and reproducing device according to claim 1 ,

wherein the magnetic recording medium is a magnetic tape.

12. The magnetic recording and reproducing device according to claim 1 ,

wherein the number of recesses is 300 to 2,000 per area of 40 μm×40 μm.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 8, 2021
From: MATSUYAMA, SO; KASADA, NORIHITO; KUROKAWA, TAKUTO
To: FUJIFILM CORPORATION
Reel/Frame 056474/0849 →
Priority Claims (2)
JP 2020-098439 · Jun 5, 2020 · national
JP 2020-217583 · Dec 25, 2020 · national
Continuity (1)
Related Publication 20210383827A1 · Dec 9, 2021
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