| 摘要 |
PURPOSE:To make constant a back tension irrespective of variations in the residual amount of an ink ribbon and without requiring any fitting operation for the ink ribbon, by a method wherein the shaft of an ink ribbon drawing-back wheel is connected through a spiral spring to a sliding wheel against which a friction member is pressed by a spring. CONSTITUTION:The shaft 24 of the ink ribbon drawing-back wheel 22 against which a rotary wheel is pressed is connected through the spiral spring 17 to the sliding wheel 18 against which the friction member 19 is elastically pressed by the spring 15. When the ink ribbon is drawn out, the sheel 22 is rotated, the rotation of the shaft 24 is transmitted by a rotation-transmitting plate 16, and the spring 17 is wound up. Therefore, when the ink ribbon is sagged, a recoil force of the spring 17 is transmitted, the wheel 22 is rotated in the opposite direction, and the sag of the ribbon is absorbed. As a result, the back tension on the ink ribbon remains constant irrespectively of the residual amount of the ink ribbon. In addition, there is no tension roller or the like, and fitting of the ink ribbon or the like is unnecessitated. |
