| 摘要 |
PURPOSE:To perform clear printing and prolong the useful lives of component parts, by taking up a printing ribbon by an amount equal to the amount by which the ribbon is paid out concurrently with a movement of a carriage, while constantly applying an appropriate tension to the ribbon even when the ribbon thus paid out is extended or contracted. CONSTITUTION:Concurrently with a movement of a carriage 3, a rotary shaft 15 is moved rightward in a body with the carriage 3. A pinion 19 is engaged with a toothed belt 17, is rotated clockwise, and a friction roller 20 fitted to the rotary shaft 18 is also rotated in the same direction. A take-up spool 24 pressed against the friction roller 20 is rotated counterclockwise to take up a used part of a printing ribbon 29. Since the diameter of the friction roller 20 is set to be slightly greater than that of the pitch circle of the pinion 19, the rotational moving quantity at a peripheral surface of the friction roller 20 is slightly greater than the moving quantity of the carriage 3, resulting in a tension on the ribbon 29. The difference between the take-up quantity and the moving quantity is substantially constant, irrespective of the roll diameter of the ribbon 29 taken up on the take-up spool 24, so that a stable operation can be achieved for a long time.
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