| 摘要 |
PROBLEM TO BE SOLVED: To provide a controller capable of correctly measuring a clearence during a recording accompanied with heater energization, thereby highly precisely controlling the clearance. SOLUTION: During calibration, in a state in which an amplitude measuring part 78 positions a head to an arbitrary measurement track, after user data is written in a data region of the measurement track as write-heat state by a write clearance control part 90, such processing is repeated that the state is switched to a read-heat state by a read clearance control part 92 and amplitude of a read-pit signal from a preamble part in a servo region is detected. A scattering calculating part 80 calculates scattering from a plurality of amplitude measurement values measured by the amplitude measurement part 78, when scattering is less than the prescribed threshold value, a contact discriminating part 82 repeats measurement processing by the amplitude measuring part 78 increasing successively a base heater control value, when scattering exceeds the threshold value, it is discriminated that a head contacts a medium. A write clearance calculating part 84 calculates clearance during write heat of the head from increment quantity of a base heater control value at the time of discrimination of contact. COPYRIGHT: (C)2008,JPO&INPIT
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