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COLOR BAR CODE SCHEME FOR READING HIGH DENSITY, XERO-GRAPHICALLY FORMED BAR CODES

IP.com Disclosure Number: IPCOM000026084D
Original Publication Date: 1990-Apr-30
Included in the Prior Art Database: 2004-Apr-05
Document File: 2 page(s) / 119K

Publishing Venue

Xerox Disclosure Journal

Abstract

The use of bar codes is becoming an increasingly popular method for marking objects for subsequent automatic identification. Bar code symbols consist of a series of dark and light (high contrast) strips of varying width. Encoding is done according to any of a number of standards.

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XEROX DISCLOSURE JOURNAL

COLOR BAR CODE SCHEME FOR READING HIGH DENSITY, XERO- GRAPHICALLY FORMED BAR CODES
Richard F. Koehler, Jr.

John F. Knapp Robert J. Gruber

Proposed Classification
U.S. C1.235/462 Int. C1. G06k 7/10

The use of bar codes is becoming an increasingly popular method for marking objects for subsequent automatic identification. Bar code symbols consist of a series of dark and light (high contrast) strips of varying width. Encoding is done according to any of a number of standards.

The generation of bar code patterns requires consistent, sharp, high density line production. Conventional xerographic techniques for forming bar codes are satisfactory for low information density patterns but fall short on high density patterns which require sharp lines of reproducible, narrow width. A bar code procedure in which the line widths and edge sharpness are non- critical would extend the capability of xerography to producing bar code patterns with information densities at or above those such as standard code 39. Typically, line width control causes problems preventing xerographic printing from achieving high densities. If the bar code itself represented changes from digit to digit rather than the digits themselves and if each adjacent bar was different from each of its neighbors, line width control would be immaterial.

Disclosed herein is the use of multiple color bars, as could be produced by a xerographic color printer, to increase bar code information density while relaxing image structure requirements. The "value" of each bar is determined by the changes in digit value of the current "bar color" from the previous "bar color." By allowing one less change in digit values than colors used, and by giving each color a value only in a circular relationship to each other color, there is one less digit value than the number of colors used, but each bar will be a different color from its neighbor. It is then only necessary to detect the bar's color and variations in width...