US 12,080,321 B2
Magnetic disk device
Koichiro Miyamoto, Yokohama Kanagawa (JP); Kenichiro Oozeki, Yokohama Kanagawa (JP); and Yu Chen, Sagamihara Kanagawa (JP)
Assigned to Kabushiki Kaisha Toshiba, Tokyo (JP); and Toshiba Electronic Devices & Storage Corporation, Tokyo (JP)
Filed by KABUSHIKI KAISHA TOSHIBA, Tokyo (JP); and TOSHIBA ELECTRONIC DEVICES & STORAGE CORPORATION, Tokyo (JP)
Filed on Sep. 12, 2022, as Appl. No. 17/942,943.
Claims priority of application No. 2022-034175 (JP), filed on Mar. 7, 2022.
Prior Publication US 2023/0282236 A1, Sep. 7, 2023
Int. Cl. G11B 21/08 (2006.01)
CPC G11B 21/08 (2013.01) 10 Claims
OG exemplary drawing
 
1. A magnetic disk device comprising:
a magnetic disk;
a magnetic head configured to record data on and reproduce data from the magnetic disk;
an actuator configured to move the magnetic head relative to the magnetic disk;
a controller configured to control the actuator; and
a ramp configured to hold the magnetic head, wherein
the controller is configured to:
in a retract operation for causing the actuator to retract the magnetic head to the ramp,
alternate detection of a back electromotive force of the actuator and application of a voltage corresponding to the back electromotive force to the actuator, and
skip the detection of the back electromotive force a predetermined number of times in response to an event that the magnetic head moves at a speed outside a predetermined range.