Patent ID: 7623314

Claim:
A head control device for controlling, through thermal expansion of a heater, a position of a head for reading and writing data from and to a storage medium, the head control device comprising: a heater control unit that increases a current supplied to the heater stepwise; an external-force sample retrieving unit that retrieves sampling values of signals each indicating a magnitude of an external force acting on the head in a moving direction of a head support mechanism of the head, the moving direction being in a direction parallel to the storage medium; an external-force evaluating unit that calculates a representative value of the sampling values retrieved by the external-force sample retrieving unit to evaluate the magnitude of the external force every time the heater control unit increases the current; and a contact detecting unit that detects contact between the head and the storage medium by comparing each evaluation result by the external-force evaluating unit with a predetermined threshold value, wherein the contact detecting unit varies the threshold value according to an absolute value of a yaw angle between a tangent to a target track on the storage medium and the head support mechanism.