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Ribbon Fault Recovery on an Electronic Typewriter

IP.com Disclosure Number: IPCOM000062349D
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Do, CL: AUTHOR [+3]

Abstract

An electronic typewriter utilizing a resistive ribbon can detect when there is a ribbon fault causing either a poorly printed character or a missing character. Minimum operator effort is required to correct the misprint caused by the poorly printed or missing character. An electronic typewriter uses an interrupt-driven printer subsystem having a document/correction area memory that also functions as a printer buffer and causes printing. This permits an operator to key ahead of the printer. When the system detects that a ribbon error has occurred due to a poorly printed or missing character, it stops printing and notifies the operator by beeping and flashing a NOPRT annunciator.

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Ribbon Fault Recovery on an Electronic Typewriter

An electronic typewriter utilizing a resistive ribbon can detect when there is a ribbon fault causing either a poorly printed character or a missing character. Minimum operator effort is required to correct the misprint caused by the poorly printed or missing character. An electronic typewriter uses an interrupt-driven printer subsystem having a document/correction area memory that also functions as a printer buffer and causes printing. This permits an operator to key ahead of the printer. When the system detects that a ribbon error has occurred due to a poorly printed or missing character, it stops printing and notifies the operator by beeping and flashing a NOPRT annunciator. The system then discards any key strokes in a keyboard buffer and deletes all text in the document/correction area in the memory between where the printer stopped and where the operator is keying. This synchronizes the printer and the memory so that the display has an accurate "window to paper" representation of the memory and the printer is properly aligned. The system then waits for the next key stroke to signify that the operator has corrected the ribbon error problem. If a block of centered text or decimal tab text was being printed at the time of the ribbon error, a portion of the block that was not printed is replaced with white spaces but the end of center mark remains. This enables the operator to rekey to properly align with the or...