Track access control system preventing unintentional delay in movement of head in non-adjusted disc device

Claim 1

A track access control system for use in a rotating disc device comprising: a head for writing and/or reading digital data on a memory disc on which a plurality of tracks are provided; a moving means for moving said head over all of said tracks on said memory disc; and a servo control means for controlling said moving means so that said head is moved to and positioned above a target track; said servo control means comprises, a real speed detecting means for detecting a real speed of said head, a speed error obtaining means for obtaining a difference between said real speed and a target speed for moving said head, a speed control means for controlling said moving means so that said head is moved at a speed according to said difference so that said real speed approaches said target speed, a real position detecting means for detecting a real position of said head, a position control means for controlling said moving means so that said head is positioned above a target track, using the detected real position, a switching means for affecting the operation of said speed control means until the real position reaches a predetermined vicinity of said target track, and effecting the operation of said position control means after the real position reaches said predetermined vicinity, a timer starting position detecting means for detecting said head reaching a predetermined position out of said predetermined position, a timer for detecting a predetermined time elapsing from the time of said reaching of the head at said predetermined vicinity, and a target speed increasing means for forcedly increasing said target speed for use in the operation of said speed error obtaining means, when the elapse of the predetermined time is detected before the head reaches the predetermined vicinity.