Browse Prior Art Database

Scheme to Improve Line Printer Throughput on Overprinted Lines

IP.com Disclosure Number: IPCOM000108529D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 3 page(s) / 107K

Publishing Venue

IBM

Related People

Dayger, DA: AUTHOR

Abstract

Significantly better throughput is experienced on buffered line printers by the consolidation of print lines which overprint at the same vertical position on a page.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Scheme to Improve Line Printer Throughput on Overprinted Lines

       Significantly better throughput is experienced on
buffered line printers by the consolidation of print lines which
overprint at the same vertical position on a page.

      It is well known that host computers are generally capable of
providing commands and data at a much faster rate than line printers
are capable of printing it.  For this reason, line printers are often
provided with a buffer in order to temporarily store several commands
and data provided by the host computer.  Such line printers are
generally known as "buffered line printers".

      It is well known that some printing applications utilize
overprinted lines.  Some examples include:
 .   Underlining words or phrases for accent.
 .   Emboldened printing where overprinting of the same characters is
used to darken the printing.
 .   Construction of special or national use characters by
overprinting two or more standard characters.
 .   Construction of bar code patterns.

      Overprinted data is generally sent as separate (two or more)
print lines with zero intervening carriage operations. As currently
practiced, each print line received from the host computer is printed
separately.  By combining overprinted lines into a single print
operation, the net throughput of such lines is increased.

      In the figure, each print line, received by the host adapter 1,
is saved as an element in the task interface queue 2.  The
microprocessor 5 reads each element from the task interface queue 2
and builds a print line image (carriage movement and print data)
record which is stored in a line image buffer 3.  The following new
rules are applied, for consecutive print lines, at the same vertical
page position:
1.   Concatenate, into one line image buffer record, those print
lines that do not overprint.  Any intervening, unspecified, print
positions are made blanks.
2.   Print lines that do overprint are placed in separate line image
buffer records.
3.   All line image buffer records, for a particular vertical page
position, are chained together into a single line image buffer 3.
4.   Each line ima...