Abstract: A low cost cartridge for supplying inked ribbon to the printing station of an associated printing device. The cartridge includes an internal tensioning mechanism for maintaining the length of inked ribbon positioned in the printing station at a constant tension independently of the quantity of ribbon remaining on the supply reel in the cartridge. The tensioning mechanism includes an elastic endless belt disposed in a closed path about a plurality of freely rotatable rollers, the path having an interference region in which portions of the belt are engaged by a portion of the outer layer of supply reel mounted ribbon and are deflected thereby to produce a drag force on the supply reel which varies with the pulling force required to withdraw ribbon from the supply reel.

Abstract: An endless ribbon cartridge for supplying ribbon to an external printing station with relatively uniform tension and including an anti-fouling mechanism to prevent snarling of the ribbon as it re-enters the cartridge. The cartridge comprises a two-piece housing having a cover and a main body portion with separate exit and entrance slots and interior boundary walls partially defining a ribbon chamber having entrance and exit portions. An endless ribbon is partially received within the chamber in random folds, the remainder of the ribbon traversing a looped path from the chamber exit portion through the housing exit slot and the housing entrance slot to the chamber entrance portion. A capstan and pinch roller assembly is provided adjacent the entrance slot to translate the ribbon along the looped path.

Abstract: Apparatus for driving a cartridge mounted rotatable ribbon capstan and take-up reel. A magnetic clutch assembly has a first gear driven by a motor for directly driving the capstan and a second gear magnetically driven by the first gear for driving the take-up reel through a gear train. The magnetic clutch assembly includes a magnetic drive ring secured to the first gear and having a plurality of inner peripheral teeth, a pair of annular magnetic members mechanically linked to the second gear, an annular magnet disposed between the magnetic members and a magnetic washer disposed below the lower magnetic member. The magnetic clutch assembly provides a yieldable driving force to the take-up reel which releases when the tension in the ribbon between the capstan and the take-up reel exceeds a predetermined threshold value. This threshold value may be adjusted by varying the dimension of the magnetic washer or the air gap between the drive ring and the annular magnetic members.