| 摘要 |
PURPOSE:To attain to enhance not only printing quality but also the life of a printing head by smoothly performing the insert of a sheet like medium, by changing the gap between a platen and a printing head by revolving the platen by predetermined quantity at the time of printing. CONSTITUTION:Because a platen shaft 2 is eccentric by a distance (l) with respect to the axis O of a platen 1, the platen 1 revolves as shown by a two- dotted line to allow a sheet like medium 15 to approach a printing wheel 12. At this time, if the sheet like medium 15 is levitated from a guide member 14, the sheet like medium 15 is shifted from a guide member 14 to generate such an obstacle that the guide member 14 is hooked with the printing wheel 12 and, therefore, the platen 1 revolves so as to press the lower end of the sheet like medium 15 to the bottom surface of the guide member 14. When the sheet like medium 15 approaches the printing wheel 12 by revolving the platen 1, the printing wheel 12 is rotationally driven by a type selection motor 11. By this method, the selection of a type is performed and the selected type is allowed to impinge against the sheet like medium 15 on the platen 11 by a printing hammer 13 through an ink ribbon to perform printing.
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