US 12,217,780 B2
Magnetic tape having characterized magnetic layer surface, magnetic tape cartridge, and magnetic tape apparatus
Norihito Kasada, Minamiashigara (JP); Yuto Murata, Minamiashigara (JP); and Nagisa Yamasaki, Minamiashigara (JP)
Assigned to FUJIFILM Corporation, Tokyo (JP)
Filed by FUJIFILM Corporation, Tokyo (JP)
Filed on Nov. 30, 2023, as Appl. No. 18/524,221.
Application 18/524,221 is a continuation of application No. 18/298,730, filed on Apr. 11, 2023, granted, now 11,887,636.
Claims priority of application No. 2022-066275 (JP), filed on Apr. 13, 2022.
Prior Publication US 2024/0105227 A1, Mar. 28, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. G11B 5/78 (2006.01); G11B 5/008 (2006.01); G11B 5/48 (2006.01); G11B 5/70 (2006.01); G11B 5/735 (2006.01)
CPC G11B 5/78 (2013.01) [G11B 5/00813 (2013.01); G11B 5/00826 (2013.01); G11B 5/4893 (2013.01); G11B 5/70 (2013.01); G11B 5/00856 (2013.01); G11B 5/7356 (2019.05); G11B 2220/90 (2013.01); G11B 2220/956 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A magnetic tape comprising:
a non-magnetic support; and
a magnetic layer containing a ferromagnetic powder,
wherein the non-magnetic support is polyethylene terephthalate, polyethylene naphthalate or polyamide,
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 60 nm or more and less than 120 nm is 8000 or more and 30000 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 2000 or less.