Magnetic tape having characterized bright regions on magnetic layer, magnetic tape cartridge, and magnetic tape apparatus

Patent metadata

Field	Value
Publication number	US-12424245-B2
Application number	US-202318538634-A
Country	US
Kind code	B2
Filing date	Dec 13, 2023
Priority date	Dec 14, 2022
Publication date	Sep 23, 2025
Grant date	Sep 23, 2025

Abstract

The magnetic tape includes a non-magnetic support, and a magnetic layer containing a ferromagnetic powder. In a binarized image of a secondary electron image obtained by imaging a surface of the magnetic layer with a scanning electron microscope at an acceleration voltage of 5 kV, the number of bright regions having an equivalent circle diameter of 75 nm or more and less than 125 nm is 100 or more and 4000 or less, and standard deviation σ of the number of the bright regions in a width direction of the surface of the magnetic layer is 400 or less.

First claim

What is claimed is:

1. A magnetic tape comprising:
a non-magnetic support; and
a magnetic layer containing a ferromagnetic powder,
wherein, in a binarized image of a secondary electron image obtained by imaging a surface of the magnetic layer with a scanning electron microscope at an acceleration voltage of 5 kV, a number of bright regions having an equivalent circle diameter of 75 nm or more and less than 125 nm is 100 or more and 4000 or less, and
standard deviation σ of the number of the bright regions in a width direction of the surface of the magnetic layer is 400 or less.

2. The magnetic tape according to claim 1 ,
wherein the standard deviation o of the number of the bright regions is 10 or more and 400 or less.

3. The magnetic tape according to claim 1 ,
wherein the standard deviation o of the number of the bright regions is 10 or more and 300 or less.

4. The magnetic tape according to claim 1 , further comprising:
a non-magnetic layer containing a non-magnetic powder between the non-magnetic support and the magnetic layer.

5. The magnetic tape according to claim 4 ,
wherein the non-magnetic powder includes an Fe-based inorganic oxide powder having an average particle volume of 2.0×10 −6 μm 3 or less.

6. The magnetic tape according to claim 4 ,
wherein the non-magnetic powder includes carbon black having a pH of 9.0 or less.

7. The magnetic tape according to claim 4 ,
wherein a thickness of the non-magnetic layer is 0.1 μm or more and 0.7 μm or less.

8. The magnetic tape according to claim 1 , further comprising:
a back coating layer containing a non-magnetic powder on a surface side of the non-magnetic support opposite to a surface side having the magnetic layer.

9. The magnetic tape according to claim 1 ,
wherein a tape thickness is 5.2 μm or less.

10. The magnetic tape according to claim 1 ,
wherein a tape thickness is 5.0 μm or less.

11. The magnetic tape according to claim 1 ,
wherein a vertical squareness ratio of the magnetic tape is 0.60 or more.

12. The magnetic tape according to claim 1 ,
wherein a vertical squareness ratio of the magnetic tape is 0.65 or more.

13. The magnetic tape according to claim 1 ,
wherein the standard deviation o of the number of the bright regions is 10 or more and 300 or less,
the magnetic tape further includes a non-magnetic layer containing a non-magnetic powder between the non-magnetic support and the magnetic layer,
the non-magnetic powder includes an Fe-based inorganic oxide powder having an average particle volume of 2.0×10 −6 μm 3 or less and carbon black having a pH of 9.0 or less,
a thickness of the non-magnetic layer is 0.1 μm or more and 0.7 μm or less,
the magnetic tape further includes a back coating layer containing a non-magnetic powder on a surface side of the non-magnetic support opposite to a surface side having the magnetic layer,
a tape thickness is 5.0 μm or less, and
a vertical squareness ratio of the magnetic tape is 0.65 or more.

14. A magnetic tape cartridge comprising:
the magnetic tape according to claim 1 .

15. A magnetic tape apparatus comprising:
the magnetic tape according to claim 1 .

16. The magnetic tape apparatus according to claim 15 , further comprising:
a magnetic head,
wherein the magnetic head has a module including an element array with a plurality of magnetic head elements between a pair of servo signal reading elements, and
the magnetic tape apparatus changes an angle θ formed by an axis of the element array with respect to a width direction of the magnetic tape during running of the magnetic tape in the magnetic tape apparatus.

Assignees

• Fujifilm Corp

Inventors

• Matsuyama So

Classifications

• G11B5/7334

  Base layer characterised by composition or structure · CPC title

• G11B5/7368

  Non-polymeric layer under the lowermost magnetic recording layer (base layers having a non-magnetic layer under a soft magnetic layer G11B5/736; magnetic recording media substrates G11B5/739) · CPC title

• G11B15/67

  by extracting end of record carrier from container or spool · CPC title

• G11B23/107

  using one reel or core, one end of the record carrier coming out of the magazine or cassette · CPC title

• G11B5/66

  the record carriers consisting of several layers · CPC title