Ribbon cartridge for printing machines

Abstract

The ribbon (17) has an external run between the type element (25) and platen of a daisy-wheel typewriter. This run stretches between terminal members (59) which protrude from side arms (33 and 34) of the cartridge casing (18) and are fixed to the distal ends of arms (39, 41) pivotally mounted in the casing (18) at pivot (52). Ribbon lift levers of the typewriter raise the arms simultaneously to position a selected one of three tracks on the ribbon at the level of the typing. The ribbon is transferred from a feed spool having a flange to a take-up spool having a core tube and which are rotatably supported by the casing. The casing comprises a bottom portion having a resilient tongue with a pawl member positioned adjacent to the take-up spool and a resilient blade adjacent to the feed spool. The core tube of the take-up spool has a series of saw teeth and the pawl member cooperates with the saw teeth for enabling the rotary movement of the core tube in the direction of rewinding of the typing ribbon, but preventing rotary movement of the core tube in the other direction, while the resilient blade engages with peripheral notches at the flange of the feed spool. The casing further provides two apertures for housing a driving toothed wheel and a control lever of the typewriter which engage with the ribbon to control the feeding of the ribbon.