Electro-strictive actuator

An impact-type dot-matrix printer head comprising:

• a printing wire having a first end facing a sheet surface to strike and print the sheet surface, and having a second end;
• an arm having a first end for supporting and moving the second end of said printing wire towards the sheet surface, said arm being rotatable about a supporting point provided on a second end of said arm, which is opposite the first end of said arm;
• an electro-strictive element positioned adjacent said arm, said electro-strictive element expanding along a longitudinal direction in response to a driving voltage so as to contact said arm, said electro-strictive element having a first surface at a first longitudinal end thereof and having a second surface at a second longitudinal end thereof;
• a mechanical member connecting said electro-strictive element to said arm at a position between the first and second ends of said arm and adjacent said supporting point, said mechanical member being adhered to said electro-strictive element and including a third surface in direct contact with said first surface;
• and
• frame means for supporting said arm by said supporting point and adhering the second longitudinal end of said electro-strictive element, said frame means including a fourth surface in direct contact with said second surface.