High speed printer module

Claim 1

In impact printer apparatus operable to rapidly print characters on a print sheet in lines and columns, and including: a first assembly including a continuously rotating rotary print drum having an axis of rotation, a second assembly including hammer means, a print transfer medium and carrier therefor, the improvement comprising: support means supporting said assemblies in spaced relation to provide a print sheet receiving slot between the drum at one side of the slot and local extent of said transfer medium and hammer means at the opposite side of the slot, said assemblies being generally spaced transverse to said axis or rotation, and said slot extending between the assemblies parallel to said axis of rotation and being open-ended, print sheet advancing means associated with said first assembly to advance an endwise feedable print sheet endwise beneath the drum and then upwardly in the slot, the support means including first and second side plates at opposite sides of the slot, the drum located between the first side plates, said print sheet advancing means including a pair of rotors rotatable about said drum axis at opposite ends of the drum and between the first side plates, and rotor drive means including ratchet means operable to rotatably index said rotors, said ratchet means includes a circular series of ratchet teeth on at least one of the rotors, said teeth projecting inwardly toward the drum axis, at least one actuator arm having rotatably reciprocating ratchet engagement with said teeth, and said drive means includes a motor operatively connected with said arm to rotatably reciprocate the arm.