| 摘要 |
PURPOSE:To obtain a high reliable small sized printing head of a high speed without failure of a piezo-electric element, by a method wherein a second plate spring is provided between a first plate spring having a printing wire as an output terminal and the piezo-electric element as a drive source, and the piezo-electric element is compressed with the second plate spring. CONSTITUTION:When a voltage is impressed on a piezo-electric element 4, the piezo-electric element 4 causes a displacement motion of a high speed and the displacement is transmitted to a second plate spring 3. Further, the motion is simultaneously transmitted from the second plate spring 1 to the first plate spring 2, and the plate spring 2 carries out free flying motion. Therefore, a printing wire 1 kept by the plate spring 2 strikes paper 9, and an ink ribbon 10 and a character is drawn by a dot matrix. Thereafter, the printing wire returns to the original position by the repulsion of printing motion and the restoring force of the spring. Then though the plate spring 2 flies free, the piezo-electric element 4 is always compressed by the plate spring 3 and the tensile stress of the piezo-electric element 4 generated at a time point when the plate spring 2 flies free is pressed thereby. Therefore, the rupture of the piezo-electric element 4 vanishes. |
