Calibration method for use in head loading/unloading type disk apparatus

A head loading/unloading type disk apparatus comprising:

• a voice coil motor for driving a carriage to move a head in a direction of radius of a disk;
• a voice coil motor velocity detection circuit for detecting a voice coil motor velocity corresponding to a back electromotive force of the voice coil motor;
• a ramp mechanism arranged outside an outer periphery of the disk to retract the head;
• a temperature sensor for measuring a temperature of the voice coil motor or an ambient temperature thereof;
• a memory;
• and
• a controller for, at the start of loading control for loading the head from the ramp mechanism onto the disk, reading out a measurement temperature of said temperature sensor, storing the readout temperature in said memory, and executing calibration for correcting a relationship between a value of a voice coil motor current flowing through the voice coil motor and the voice coil motor velocity detection value detected by the voice coil motor velocity detection circuit, said calibration being executed by obtaining a voice coil motor velocity detection value detected by the voice coil motor velocity detection circuit in a state where an actual velocity of the voice coil motor is set to zero and a current is supplied to the voice coil motor, and, after loading the head, monitoring the measurement temperature of said temperature sensor, and reexecuting said calibration if a temperature change from the measurement temperature during loading stored in said memory is not less than a prescribed value.