To prevent the sagging of an ink ribbon occurring near a supplying core at the finishing of the forward motion of a carriage.
A supplying knob 24 is made axially shiftable on a shaft 241 and a back tension spring 25 is inserted below the supplying knob 24. The pins 331a of a supplying core 33a, amound which a monochromic ink ribbon is wound, engage with an upper stage ratched gear 24a by abutting against the stepped part of the supplying knob 24, resulting in moving the supplying knob 24 downwards and shortening the back tension spring 25. The pins 331b of a supplying core 33b, around which a polychromatic ink ribbon is wound, engage with a low stage ratched gear 24b without abutting against the stepped part of the supplying knob 24, resulting in moving the supplying knob 24 upwards by means of the elastic force of the back tension spring 25 and the back tension spring 25 extends. By the change of the elastic force due to the change of the length of the back tension spring 25, the magnitude of the back tension acting on the supplying knob 24 changes.
YAO KEIJI
MORIMOTO AKINORI
TANAKA KENJI
