Segmented drum bar helix printer
AssigneeInternational Business Machines Corporation
InventorsRobert A. Sebrosky, William D. Thorne
Life of this patent
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Abstract
Disclosed is an improved form of a mosaic printer of the bar helix type. The helical raised threads on the printer drum instead of being continuous are broken into segments which are offset axially on the drum. This produces a significant increase in throughput by reducing waiting time for the drum to rotate a section of continuous thread into alignment with a hammer at the start of a new helical pattern.
Claims7
In a mosaic printer having a cylindrical rotating drum, rotating at some arbitrary fixed rate, the outer surface of which has at least one raised spiral thread, and having at least one print hammer located adjacent to said drum and being provided with means for firing said hammer to impact against said spiral thread at desired times, and a printing medium interposed between said hammer and said thread and means associated with said printing medium for moving said medium at some arbitrary feed rate between said hammer and said drum to effect printing operations in either incremental or fixed speed modes, and timing means for controlling the times during the revolution of said drum that said hammer is moved to impact said medium against a portion of said spiral thread, the improvements comprising:
- said spiral thread being divided into a plurality of segments;
- and
- the endings and beginnings, respectively, of each of said segments relative to the preceding and succeeding segments thereof being offset from one another circumferentially on said drum by a distance at least equal to that distance traversed by any point on the periphery of said drum at said rate of revolution thereof during the time required by said moving means to move said print medium at said rate to a new printing position.
Dependencies are inferred from the claim text.