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Maximum Throughput Using a Bidirectional Printer

IP.com Disclosure Number: IPCOM000074107D
Original Publication Date: 1971-Mar-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Beitel, BJ: AUTHOR

Abstract

Variable length records from a software left margin are printed with a bidirectional printer. Printing only as much as is required so as to increase throughput is realized, by padding where necessary to make pairs of print lines be equal in length.

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Maximum Throughput Using a Bidirectional Printer

Variable length records from a software left margin are printed with a bidirectional printer. Printing only as much as is required so as to increase throughput is realized, by padding where necessary to make pairs of print lines be equal in length.

Bidirectional serial printers have been designed to print fixed length records in both directions (i.e., left to right, right to left). In bidirectional printing mode, right to left print is initiated anytime the print operation is started when the print head is not at physical left margin 10. This bidirectional printing feature may be selected by a bit in a computer originated instruction or suppressed by that same bit making the printer only operate from left to right.

In this arrangement, the "current" line 11 to be printed is buffered until the next print operation is requested. At that point the length of the next line 12 is compared to the length of the "current" line 11 so as to pad one of the lines with blanks to make the two lines equal in length. The current line is then printed from left to right including enough blanks 13 to incorporate printing the next line 12 from right to left.

Assume four lines 11, 12, 14 and 15 of different record length are to be printed between software defined margins 17 and 18 and physical margins 10 and 19. Line 11 is received and buffered. Line 12 is then received. Blanks are then added to line 11 so that the print head will be po...