| 摘要 |
PURPOSE:To attain highly accurate adjustment for applied voltage even when the resistance value of exchanged thermal head is dispersed by a method in which a monitoring resistor is provided near plural heating resistor element, and on the basis of the resistance values of the resistors, the amount of voltage to be applied to the head is adjusted. CONSTITUTION:In a thermal head 1, plural heating elements HE are provided on a base material and a monitoring resistor ME of the same constitution as the heating element HE is provided near the heating elements HE. When a monitor voltage Vm and a reference voltage Vr based on the resistance value Rwo of the monitoring resistor ME are put in a differential amplifier DA, the varied portion of the monitor voltage Vm is output in the form of an output V3. By lapping the output V3 on a constant-voltage regulator SR, a voltage VO[VO=V(fixed output of regulator)+Vs]based on the variation in the monitor voltage Vm is applied to the thermal head. |
