Driver circuit for piezoelectric actuator, and impact dot-matrix printer using the driver circuit

摘要

An impact dot-matrix printer having a print head which includes a piezoelectric element and a print element such as a print wire activated by the piezoelectric element, wherein the print head is movable between a printing area and a non-printing area of the printer. A pressure detector is provided for detecting a printing pressure of the print element. The detector includes a pressure-sensitive element which is disposed in a predetermined position in the non-printing area, in which the print element is operable to act on the pressure-sensitive element. A voltage controller connected to the pressure detector and the piezoelectric element is provided for controlling a voltage applied to the piezoelectric element, based on an output of the pressure detector, such that the printing pressure coincides with a predetermined value. Since the printing pressure is varied with a temperature of the piezoelectric element, the voltage may be controlled based on the temperature of the piezoelectric element detected by a temperature sensor.