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Bar Code Printing for Improved Reliability

IP.com Disclosure Number: IPCOM000048395D
Original Publication Date: 1982-Jan-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 5 page(s) / 74K

Publishing Venue

IBM

Related People

Bobart, KL: AUTHOR [+2]

Abstract

This system makes possible the printing of bar code on paper of various qualities and with some defects with a high probability of subsequently reading the bar code successfully. A line of bar code is read immediately after it is printed and is ultimately printed again with a special code if it can not be recognized as accurately printed.

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Bar Code Printing for Improved Reliability

This system makes possible the printing of bar code on paper of various qualities and with some defects with a high probability of subsequently reading the bar code successfully. A line of bar code is read immediately after it is printed and is ultimately printed again with a special code if it can not be recognized as accurately printed.

When printing a high density bar code in an office or word-processing environment, it is possible to encounter paper conditions that cause "poor" print quality. Under these circumstances, it ie possible to print a line of bar code that cannot be decoded. This can be the result of various physical defects on the paper, or smudges, or smears. Such problems can be avoided by printing in a different location which does not have the defects or has slightly different print quality characteristics.

When a single block of information, called a logical record, is to units, called messages, to be recorded in individual lines on the paper or other medium printed upon. When a message is to be recorded, or printed, a "start" code indicating that the physical record is the first attempt at printing the message is printed ahead of the message, and a similar code indication is made in an "end" code which is appended to the message (Fig. 1). These codes are called the "original" start code (OSC) and the "original" end code (OEC). After the message and start and end codes are printed, an attempt is made, before proceeding to a new line, to verify or check the physical record.

During this verification process, the physical record is scanned and decoded up to three times, each with the scanner in a slightly different location with respect to the physical record. If no decoding errors occur, then the message on the physical record is "verified" and the printer is moved to the next line and the next message is encoded and printed. If the physical record cannot be verified, the printer is moved to the next line, but another copy of the first message is printed; this time, different start and end codes are used which indicate that the physical record contains a repeat of the previous message. These codes are called "repeat" start code (RSC) and "repeat" end code (REC).

The same reading for verification is made on this physical record also. If successful, the next message is encoded; if not successful, a "repeated" message can be printed in another physical record and the same repeat start and repeat end codes can be used. The process reasonably can be duplicated several times.

An example of a store of a logical record is shown in Fig. 2. In the example shown, the logical record to be stored must be divided into three messages (M1, M2, and M3) to fit the physical record length of the bar code medium. The first physical record containing message 1 (M1) is printed with original start and end codes (OSC, OEC). Assuming that line cannot be verified, a second line containing M1 is pr...