| 摘要 |
A printer and in particular a printer adapted for use with a thermal print head is provided. The printer includes a power transmission which controls two clutches with a single electromagnetic driving unit. A clutch of a power transmission is initialized without the use of a detector by dividing the perimeter of the clutch into N equal rotating angles each equal rotating angle being further subdivided into a large rotating angle and a small rotating angle in combination with a preselected energization period for an electromagnetic control member which assures the initialization of the clutch in a desired position. The clutch is advanced one position by a second energization period of the electromagnetic control member. The carriage mover of the printer allows the carriage to reciprocate in response to forward and backward rotation of a shifting shaft and at at least one end of the range of motion of the carriage the shifting shaft can continue to freely rotate even though the carriage cannot. The ribbon movement mechanism for a thermal printer only advances the ribbon when a character is to be printed by only rotating a gear member which selectively engages a rack on the printer case.
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