US 12,367,906 B2
Magnetic recording cartridge including magnetic recording medium having a variation in width
Takahiro Takayama, Tokyo (JP); and Minoru Yamaga, Tokyo (JP)
Assigned to Sony Group Corporation, Tokyo (JP)
Appl. No. 18/286,273
Filed by Sony Group Corporation, Tokyo (JP)
PCT Filed Feb. 15, 2022, PCT No. PCT/JP2022/005885
§ 371(c)(1), (2) Date Oct. 10, 2023,
PCT Pub. No. WO2022/230308, PCT Pub. Date Nov. 3, 2022.
Claims priority of application No. 2021-077716 (JP), filed on Apr. 30, 2021.
Prior Publication US 2024/0203455 A1, Jun. 20, 2024
Int. Cl. G11B 5/78 (2006.01); G11B 5/65 (2006.01); G11B 5/70 (2006.01); G11B 5/73 (2006.01); G11B 23/027 (2006.01); G11B 23/107 (2006.01)
CPC G11B 5/78 (2013.01) [G11B 5/65 (2013.01); G11B 5/70 (2013.01); G11B 5/73 (2013.01); G11B 5/73927 (2019.05); G11B 23/027 (2013.01); G11B 23/107 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A magnetic recording medium comprising:
a base layer having a loss modulus at 65° C. of 0.40 GPa to 0.01 GPa,
wherein the magnetic recording medium is configured to be accommodated in a magnetic recording cartridge in a state of being wound around a reel of the magnetic recording cartridge,
when a variation in width is measured over an entire length after storage at 65° C. for 360 hours in the state of being wound around the reel,
a sign of variation in width Δout on an outer side of winding is a positive sign or a negative sign and a different sign from a sign of variation in width Δin on an inner side of winding, and
the variation in width is 0 ppm at any position of two portions that are positioned opposite each other with respect to a center line of the entire length in a case where the entire length is divided into four portions by dividing into four equal parts.