Bi-directional belt drive, print head mounting means and printing plane

Abstract

A bidirectional belt-drive for printers and the like comprising a carriage assembly movable across a paper web and supporting a print head mounting bracket. A belt has upper and lower runs extending through guide passageways in the carriage assembly. Independent jam cleat assemblies are normally biased by single spring means to a neutral position so as to be displaced from both runs of the belt. Swingably mounted knurled supporting surfaces cooperate with the jam cleat assemblies to enhance gripping of the fabric belt. Each jam cleat assembly has a pair of cooperating arms whose free ends are arranged to engage one another and extend between the arms of the single torsion spring means. The carriage assembly print head slidably receives the mounting bracket which is urged in the forward direction by bias means and may be adjustably positioned by adjustable cam means to enable the carriage assembly to maintain a fixed position relative to the platen and requiring only movement of the print head mounting bracket. The carriage assembly includes an open frame-shaped casting of a light-weight material significantly reducing inertia as well as the load imposed upon the driving system. Movement of the carriage assembly, regardless of the direction of said movement, drives a ribbon cartridge drive shaft, through a pair of selectively operable clutch assemblies mounted to move with the carriage and rotated by wires encircling the clutch assemblies.