A disk drive apparatus is disclosed wherein a track jumping operation of an objective lens is stabilized. A donor web is disposed on one side of the path; a platen roller is disposed on the other side of the path and supports the sheet during printing. The respective impression cylinders of the front-side offset printing unit and the back-side offset printing unit are placed up against each other such that said printing units receive and output sheets between said impression cylinders. Since only one block is decoded per time, the traceback through the coded block signal is short. The repeatable component correcting module corrects the repeatable component based on transfer characteristics of the speed control module and the motor and generates a corrected repeatable component. When the motion differences are small, the suspect region is considered part of the object and removed from the object mask as an occlusion.