Patent ID: 7466329

Claim:
A printer device that prints an image to a printing paper using a thermal head formed with a plurality of heating resistors, the device comprising: edge position detection means for performing edge position detection to an incoming printing paper using the thermal head based on a change of temperature increase observed in, as a result of energization, any of the heating resistors opposing the printing paper and the remaining heating resistors not opposing the printing paper; and control means for exercising control over an image printing operation using the thermal head based on a detection output derived by the edge position detection means, wherein the edge position detection means performs the edge position detection to the printing paper using the thermal head based on a change of a resistance value caused by the temperature increase observed in the heating resistors of the thermal head, and wherein in an edge position detection mode, the edge position detection means detects the change of the resistance value observed in any of the heating resistors located at a center by energizing the heating resistors adjacent thereto at the same time.