US 12,380,924 B2
Magnetic tape with characterized AlFeSil abrasion value, magnetic tape cartridge, and magnetic tape apparatus
Takuto Kurokawa, Minamiashigara (JP); Yujin Shibata, Minamiashigara (JP); Norihito Kasada, Minamiashigara (JP); and So Matsuyama, Minamiashigara (JP)
Assigned to FUJIFILM Corporation, Tokyo (JP)
Filed by FUJIFILM Corporation, Tokyo (JP)
Filed on Sep. 14, 2023, as Appl. No. 18/467,426.
Claims priority of application No. 2022-146867 (JP), filed on Sep. 15, 2022.
Prior Publication US 2024/0112697 A1, Apr. 4, 2024
Int. Cl. G11B 5/62 (2006.01); G11B 5/008 (2006.01); G11B 5/588 (2006.01); G11B 5/84 (2006.01)
CPC G11B 5/62 (2013.01) [G11B 5/00817 (2013.01); G11B 5/588 (2013.01); G11B 5/84 (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 an AlFeSil abrasion value measured on a surface of the magnetic layer is 20 μm or more and 50 μm or less, and
standard deviation σ of the AlFeSil abrasion value obtained in a width direction of the surface of the magnetic layer is 5.0 μm or less,
the AlFeSil abrasion value being an arithmetic average of five measured values obtained by measuring an abrasion width of an AlFeSil square bar for each of five measurement points of the AlFeSil square bar by the following method using a reel tester at 23° C. and a relative humidity of 50%, and the standard deviation σ of the five measured values being defined as standard deviation σ of the AlFeSil abrasion value obtained in a width direction of the surface of the magnetic layer of the magnetic tape to be measured:
the magnetic layer surface of the magnetic tape is brought into contact with one edge side of the AlFeSil square bar with a wrap angle of 12° and a tension applied in a longitudinal direction of the magnetic tape of 1.0 N so as to be orthogonal to a longitudinal direction of the AlFeSil square bar;
in this state, a portion of the magnetic tape to be measured over a length of 580 m in the longitudinal direction is run at a speed of 3 m/sec to make 50 times of reciprocation and the abrasion width of the AlFeSil square bar after the 50 times of reciprocation is measured for each of five measurement points, the AlFeSil square bar being an AlFeSil square bar in which a value of a length L of one edge side in contact with the magnetic layer surface is larger than a value of a width W of the magnetic tape, and each of the five points where the abrasion width of the AlFeSil square bar is measured is a point selected randomly in each section obtained by dividing a region having the length W in contact with the magnetic layer surface into five sections at the edge of the AlFeSil square bar.