PURPOSE: To enable to drive a printing hammer by a low voltage and to obtain a large displacement, by a method wherein a plurality of ceramic sheets are laminated, and electrodes are provided on both sides of each of the ceramic sheets so that the electrode provided between adjacent ones of the sheets functions as a common electrode for the adjacent sheets, thereby constituting a multilayer construction.

CONSTITUTION: A plurality of the ceramic sheets 7 are laminated to constitute a multilayer construction, electrodes 8 of appropriate pattern are provided at predetermined positions of both sides of each of the ceramic sheets 7, and the electrode 8 provided between adjacent ones of the sheets 7 is used as a common electrode for the adjacent sheets 7. The directions of polarization of the electrodes 8 are so set that they are opposite for the adjacent ceramic sheets 7, as indicated by arrows P. Accordingly, since a bimorph-type printing hammer is provided by utilizing the transverse effect of mechanical strains of a piezoelectric ceramic, there is no need for a separate magnifying mechanism. In addition, since the electrodes are provided on both sides of each of the ceramic sheets constituting the piezoelectric ceramic, the hammer can be driven by a low voltage.