| 摘要 |
PURPOSE:To enable to position a platen with high accuracy, by a method wherein a small gear for positioning a platen is engaged to a final-stage gear of a transmitting mechanism, and a detent gear having a large diameter and a large number of teeth to which a detent member is elastically engaged is provided coaxially with the small gear. CONSTITUTION:A gear transmitting mechanims 3 consists of a driving gear 5 fixed to a shaft 4 of a stepping motor 2, an idler gear 6, the small gear 7 for positioning the platen, and the final-stage gear 9 fixed to a shaft 8 of the platen 1. The detent gear 11 having a large diameter and a large number of teeth is fixed to a shaft 10 for the small gear 7, and a press roller 13 of the detent member 12 is pressed between the teeth of the gear 11 by a spring 14. Accordingly, since the detent gear has the large diameter and the large number of teeth, paper can be fed by the detent by a minute amount step at a time through the rotating ratio between the small gear and the final-stage gear, and the platen 1 can be positioned with high accuracy by the detent member 12 and the detent gear 11. |
