| 摘要 |
PURPOSE:To prevent the non-uniformity of density and the rupture of a ribbon by imparting constant back tension to the ribbon by transmitting the wt. of a bobbion to a friction plate through a lever member. CONSTITUTION:A first lever member 13 transmitting the wt. of a follower bobbion 2 to a friction plate 11 in an enlarged state and a second lever member 14 are arranged. That is, the wt. of the follower bobbin 2 is supported by the lever member 13 and the short length part 14b of the lever member 14 nearer to the leading end thereof from the shaft 16 thereof is contacted with the friction plate 11 from above to press said friction plate 11. Therefore, the half of the wt. of the follower bobbin is supported and transmitted to the friction plate 11 through the lever members 13, 14 and, when the wt. changes by the drawing-out of a ribbon, the follower bobbin 2 moves up and down along the slot 9 opened to a frame 4. A sleeve 10 is pressed to the outer surface of the friction plate 11 and a friction force imparting member 12 imparting constant initial torque by friction force is contacted between the friction plate 11 and the sleeve 10. |
