Film transfer apparatus and a film transfer roller used therein

A film transfer apparatus comprising:

• a film transfer roller;
• a film transfer ribbon having a transfer film on one side thereof;
• a transfer head defined by the film transfer roller;
• a feed core about which the film transfer ribbon is entrained such that the transfer film is oriented outwardly;
• a take-up core for taking up the film transfer ribbon fed from the feed core past the transfer head;
• a take-up core support shaft;
• an apparatus casing for replaceably accommodating therein the feed core and the take-up core, the casing including at least one of a feed core support shaft for rotatably mounting the feed core with the feed core dismountable in a direction of width of the ribbon and said take-up core support shaft for rotatably mounting the take-up core with the take-up core dismountable in the direction of the ribbon width;
• a pair of transmission means provided respectively to the feed core support shaft and the take-up core support shaft for causing the take-up core to provide a ribbon take-up speed higher than a ribbon feeding speed provided by the feed core;
• and
• a slip coupling mechanism for slippably coupling between rotation of the take-up core and rotation of the feed core,
• wherein, in response to movement of the transfer head from an upstream side in a ribbon feeding direction of the feed core with the transfer head pressing the film transfer ribbon against an object surface, the feed core is rotated to continuously feed the film transfer ribbon while a portion of the ribbon is taken up about the take-up core,
• wherein an engaged portion formed in an inner peripheral engaging surface of the take-up core for engagement with an engaging portion formed in an outer peripheral engaging surface of the take-up core support shaft is rendered elastically deformable to a non-transmitting position responsive to a relative rotational force exceeding a predetermined level applied thereto, with this elastically deformable engaging portion constituting the slip coupling mechanism;
• and
• the engaged portion of the take-up core is provided with a mechanical strength lower than the engaging portion of the take-up core support shaft .