| 摘要 |
PURPOSE:To reduce the number of parts, eliminate operational defects and prevent structural scale-up in size by controlling printing pressure of a printing member without changing the position of balls, using as single cam rotating at a fixed position and a rotary element being engaged with an electromagnetically actuated slider. CONSTITUTION:A printing member 26 is energized counter-clockwise by a spring 84 having a weak resilient force. A locking block 50 is locked an elongation part 42 of a rotary lever 36 and therefore, its motion is restricted, resulting in the movement of a roller 34 in an arrow direction 78 by the force of a spring 32 when the roller 34 comes to a position where it is engaged with a concave part 76. If a rocking lever 24 rotates in an arrow direction 78 due to the high elasticity of the spring 32, the lever 36 rotates in an opposite direction to an arrow direction 74 around an axis 30, and a locking piece 50 of the printing member 26 is unlocked. Subsequently, an axis 18 is turned clockwise and a printing ball 12 touches a platen 14, ending a printing operation. Thus a slider 54 need not return to a home position every time it completes printing, so that rapid operation is achieved and a uniform printing condition is obtained. |
