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US 4,730,780 AGranted
Ink ribbon cassette
AssigneeCanon Kabushiki Kaisha
InventorNoboru Shimoyama
Life of this patent
Estimating the term…
Abstract
An ink ribbon cassette includes a case, supply side core rotatably held by the case and having an uneven portion in a portion thereof, an ink ribbon wound on the core, a take-up side core rotatably held by the case to take up the ink ribbon, and a spring resiliently engaged with the uneven portion of the supply side core and resiliently pressing the outer periphery of the ink ribbon wound on the supply side core.
Claims4
An ink ribbon cassette including:
- a case;
- a supply core rotatably held by said case and having a detent portion thereof;
- an ink ribbon wound on said supply core,
- a take-up core rotatably held by said case to take up the ink ribbon;
- and
- an elongated spring bent and fixed at its center to have a first free end which is in resilient engagement with the detent portion of said supply core and a second free end which is in resilient contact with the outer periphery of the ink ribbon wound on said supply core, said second free end moving according to the amount of the ink ribbon wound on said supply core to reduce urging force to the ink ribbon and impart to the ink ribbon a substantially constant tension for all amounts of ink ribbon wound on the supply core.
3 more elements
Dependencies are inferred from the claim text.