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Variable-Length Subscan Ring for Multi-Pitch Printers

IP.com Disclosure Number: IPCOM000042622D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Carrington, JE: AUTHOR [+2]

Abstract

The controls for printers having an endless continuously moving type carrier include buffer address circuitry controlled by a subscan ring which is used to control the sequence of buffer storage positions addressed by the address circuitry in each of a plurality of subscans of a print scan. The subscan controls include decode circuitry which alters the length of the subscan ring by changing the number of subscans dependent on the pitch of the type carrier characters. In printers using an endless band, chain or train, printing is accomplished by comparing print data in a print line buffer with character data in a carrier buffer during an interval referred as a subscan. During a subscan, a fraction of the characters on the type carrier will be aligned for printing.

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Variable-Length Subscan Ring for Multi-Pitch Printers

The controls for printers having an endless continuously moving type carrier include buffer address circuitry controlled by a subscan ring which is used to control the sequence of buffer storage positions addressed by the address circuitry in each of a plurality of subscans of a print scan. The subscan controls include decode circuitry which alters the length of the subscan ring by changing the number of subscans dependent on the pitch of the type carrier characters. In printers using an endless band, chain or train, printing is accomplished by comparing print data in a print line buffer with character data in a carrier buffer during an interval referred as a subscan. During a subscan, a fraction of the characters on the type carrier will be aligned for printing. Multiple subscans comprise a scan, and multiple scans comprise a print line during which all type carrier characters are aligned with all hammer positions of the print line. The number of subscans required per scan is related to the ratio of type character pitch and the print hammer pitch, and can be calculated with the following formula:

(Image Omitted)

The following table shows the parameters for a .133 and .166 pitch type carrier: Referring to Fig. 1, a variable-length subscan ring comprises latches L1 - Ln which generate subscan pulses SS1 - SSn used to control address and other circuits of the printer controls. Ring Advance pulses are supplied to...