| 摘要 |
PURPOSE:To enable dot pins to be driven at the minimum energy without catch of dot pins on a ribbon, by detecting the moment when the tip of a dot pin reaches printing paper for every dot pin, and by independently controlling the timing for each dot pin to return to the origin. CONSTITUTION:A detection board 45 is fitted with a piezoelectric element at a position nearly above an end of armature 37 opposite to the end where dot pins are secured. When dot pins 38 impinge on the printing paper, the piezoelement emits output A. When output C resulting from comparison with it is applied to flip flop 74 LS107, this element is reset by drive signal D and emits output E showing low level to high level. When the output of an impact detection circuit outputted on the reaching of dot pins to the printing paper shows low level, coil current flows. Therefore, the timing for dot pins to return to the origin is controlled for every dot pin, and the catch of pins on the ribbon can be eliminated. As the result, power necessary pin drive can be reduced as much as possible. |
