Ink ribbon cartridge including a movable ribbon tensioning guide for a printing machine

摘要

An ink ribbon cartridge for a printing machine of the type which includes a carriage moving in a direction parallel to the line of typing and a needle printing head, which can move on the carriage perpendicular to its direction of movement to advance and retract the head with respect to that on which printing is effected. The cartridge is supported by the carriage and includes a container having a cover, a base and a series of inner walls which bound an opening to house the needle printing head. The cartridge comprises two arms to guide out a portion of an inked ribbon near the head. The container arranges the ribbon in loose folds and supports a pair of rollers for the single directional feed of the ribbon. A tensioning unit in the cartridge includes a roller borne by a coupling having two ends housed and guided in corresponding slots of the base and of the cover, substantially parallel to the direction of movement of the head in relation of the carriage. The coupling of the roller is able to house a stud of the head and is free to move with play in the slots. The roller engages the ribbon and is movable in a first direction to pay out ribbon to the external length as the head is advanced and is movable in a second opposite direction to take up slack from the external length as the head is retracted.