Patent ID: 7196980

Claim:
An information disk recording/reproducing device, in which recording or reproduction can be performed on an information disk having an information recording track formed like a spiral or a concentric circle, comprising: a disk rotating unit for rotating an information disk; a rotational position information output unit for outputting rotational position information based on information indicating a rotation angle of the disk rotating unit by dividing one rotation into m angular divisions; a reading unit for reading an information signal from an information disk; a radius direction driving unit for driving the reading unit in a radius direction of an information disk; a track cross detecting unit for detecting crossing of and generating a track cross signal based on a reproduction signal when the reading unit traverses an information recording track by the driving of the radius direction driving unit; a track cross direction detecting unit for detecting a direction of a track crossing caused by a crossing based on the reproduction signal when the reading unit traverses an information recording track by the driving of the radius direction driving unit; a counting unit for counting pulses of a track cross signal from the track cross detecting unit, with a code indicating a track cross direction from the track cross direction detecting unit, based on an output from the rotational position information output; and a control unit which rotates the disk rotating unit at a first speed, obtains a first counted value of the counting unit while not operating the radius direction driving unit, rotates the disk rotating unit at one or more rotational speeds higher than a first rotational speed, obtains a second counted value from the counting unit while not operating the radius direction driving unit, and compares a predetermined threshold value to a vibration detection value as a function of a sum of absolute values of a difference between the first counted value and the second counted value.