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Browse Prior Art Database

Bar Code Printing Using Hybrid Dot-Bar Matrix

IP.com Disclosure Number: IPCOM000100024D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 3 page(s) / 98K

Publishing Venue

IBM

Related People

Lee, HC: AUTHOR [+2]

Abstract

This article describes a picket fence bar code alphabet for engraved band line printers that overcomes density variation and throughput problems.

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

Bar Code Printing Using Hybrid Dot-Bar Matrix

       This article describes a picket fence bar code alphabet
for engraved band line printers that overcomes density variation and
throughput problems.

      The picket-fence orientation of the bars/spaces for bar code
printing is shown in Fig. 1.  Printing picket-fence bar code char
acters on engraved band printers typically requires that relatively
long thin characters appear on the print band, as shown in Fig. 2.
The vertical dimension of these characters is approximately .180".
When the paper is incremented 1/6" between print lines, there will be
a slight vertical overlap between vertical bars printed on two
successive lines (Fig. 3).  The vertical dimension of these bars is
such that there will always be some vertical overlap, taking all the
printer tolerances into account.

      The problem with this printing scheme is that, for relatively
small parallel misalignments between the print hammers striking the
bars and the bars being struck, density variations in the printing
will occur.  In particular, the bars printed are prone to having
light print density at the top or bottom of the printed bars.  This
is unpleasing to the eye and can cause the bars to be misread by bar
code readers.  If the bar lengths are shortened to, say, one-half or
one- third of the total length (approximately .180"), the light
top/light bottom density variation problem disappears.  However,
creating shorter-length bars requires two or three times more
overstriking or printing.  This in turn has a large negative effect
upon throughput.  In order to avoid this throughput deficiency while
still maintaining uniform print density, a series of horizontal bar
and dot elements are used, as described below.

      Typically, a hammer will cover a printed area that is 1/10"
wide X 1/6" high.  To provide complete graphics capability, this area
is broken into a 4 X 4 array.  A font or character set is formed
which includes single dots and/or horizontal bars for each of the 4
rows (or 4 colu...