Patent ID: 8203801

Claim:
A disk device comprising: a disk information storage medium, wherein the disk device is configured to rotate the disk information storage medium in order to record and reproduce information on the information storage medium using a head configured to slide in contact with a lubricant coating on the information storage medium, and wherein a combination of a sliding speed U, a contact area of the head A and a normal force applied to the contact area of the head N is configured to satisfy that U×A/N is within a monotonously increasing region where a coefficient of friction associated with a frictional force in a contact area of the head facing the information storage medium monotonously increases as U×A/N increases; a pressing module configured to press the head towards the information storage medium with a variable pressing force; and a controller configured to cause the pressing module to adjust the pressing force to maintain U×A/N within the monotonously increasing region for the coefficient of friction.