Abstract: A thermal ink ribbon cassette for a mailing machine has an anti-reverse spring for preventing rotation of the take-up spindle in the unwinding direction; a constant-tension drag arrangement, including an expansible stub axle, a cooperating expansion member, and a drag gear mounted on the stub axle in meshing engagement with an array of gear teeth surrounding the base of the ribbon supply spindle; and a guide bar for defining an optimal ribbon path between the entrance opening of the cassette housing and the take-up spindle.

Abstract: An inked ribbon core is formed with interference structure, providing an internal cylindrical contact surface, and a longitudinal rib, the interference structure and rib frictionally engaging corresponding spindle structures to secure the core on the spindle.

Abstract: An inked ribbon core has an internal collar and a longitudinal rib which frictionally engage corresponding spindle structures to thereby secure the core in its fully mounted position, as determined by a stop ring.