Browse Prior Art Database

Serial Printer Bidirectional Data-Handling Technique

IP.com Disclosure Number: IPCOM000100149D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 3 page(s) / 94K

Publishing Venue

IBM

Related People

Helfenberger, CD: AUTHOR [+3]

Abstract

This invention describes a means of loading data serially into a print head with multiple print elements. This technique minimizes the bandwidth required of the printer's microprocessor.

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

Serial Printer Bidirectional Data-Handling Technique

       This invention describes a means of loading data serially
into a print head with multiple print elements.  This technique
minimizes the bandwidth required of the printer's microprocessor.

      Shown in Fig. 1 is a schematic diagram of the circuit used in
this technique.  This circuit is part of the print head driver card
which would be mounted on the print head carrier in a dot matrix
printer.  The shift registers shown in Fig. 1 are serial input
latched drivers such as Sprague Electric Company's UCN-5821 or
UCN-5841.  Since most integrated drivers use unidirectional shift
registers, this invention allows a more efficient microcode interface
by allowing the data to be arranged in the print buffer in the same
order regardless of direction of print head travel.

      Referring to Figs. 1 and 2, the following is a description of
how this invention works and the benefits derived from it.  Fig. 2
shows how data is placed in a print line buffer with each slice of
data being represented as 1A1, 1A2, etc.  In the example shown in
Fig. 1, there are 6 blocks; therefore, 6 slices of data are required
for each column of dots printed within a character cell, each slice
being one byte long.  Figs. 1 and 2 show 6 slices (a 48-element print
head), but this technique could be used for any print head requiring
more than one register.

      The data is placed in the buffer in sequence, as it would be
printed on paper.  The bottom numbers in Fig. 2 represent which
register block that slice of data should reside in after it is loaded
serially.  The top numbers in Fig. 2 show how the data would be
grouped together to form all the dots that are to be printed within
one vertical column in a print cell...