Patent ID: 8279551

Claim:
A head positioning method for an eccentric track in a head positioning device including a disk which has servo information corresponding to a number of tracks, a rough moving stage, a fine moving stage mounted on the rough moving stage, a composite magnetic head mounted on the fine moving stage and an actuator for moving the composite magnetic head in a radial direction of the disk at high speed in order to position the composite magnetic head in a predetermined eccentrically rotating track, comprising the steps of positioning the composite magnetic head in the predetermined track by moving the fine moving stage with the movement of the composite magnetic head being fixed, generating a position detection signal of the composite magnetic head for one track revolution corresponding to a position slip of the composite magnetic head from the predetermined track which rotates eccentrically by a read signal of the servo information from the composite head corresponding to the predetermined read start signal, detecting an amplitude of the position detection signal for one track revolution and a rotation angle from the position of the predetermined read start signal to the maximum peak position, obtaining an actuator drive signal having maximum extension and contraction amount corresponding to the maximum position slip amount indicated by the amplitude of the position detection signal from a memory which stores a number of drive signal waveforms of the actuator to extend or contract the actuator corresponding to amounts of the eccentricity of a track in one revolution of the disk, wherein the composite magnetic head is positioned in the predetermined track by driving the actuator by the actuator drive signal obtained correspondingly to the predetermined read start signal with the position corresponding to the generating timing of the predetermined read start signal which is determined by the rotation angle as a reference or a signal having a waveform which is an inversion of the waveform of the actuator drive signal, and wherein the memory has a storing table which stores a number of the actuator drive signals for generating the maximum extension and contraction amount of the actuator corresponding to the maximum position slip amount with respect to the maximum position slip amount of the composite magnetic head from the eccentric tracks corresponding to the number of track eccentricity amount; and driving the actuator by the actuator drive signal or the signal having a waveform which is an inversion of the actuator drive signal and the step of obtaining the position corresponding to the generation timing of the predetermined read start signal as a drive start voltage value determined by the rotation angle, wherein the step of detecting the amplitude and the rotation angle is to detect an angle from the position of the predetermined read start signal to the maximum peak position as the rotation angle.