Online Bar Code Verification: A State-of-the-Art Technology

The trend in bar code verification is moving to in-line verification rather than off line sampling techniques.

The face of bar code verification has changed dramatically over the past few years with continuous in-line verification becoming more and more common. After-the-fact sampling with cumbersome handheld systems is becoming a thing of the past. This is only the latest trend following the move to ANSI-based verification from older "Traditional" methods. The result has been greater efficiency for printers and better quality for customers. A classic win-win situation brought about by new technology.

Most customers and printers have already shifted to the ANSI method of bar code verification and with good reason. The ANSI method addresses virtually all aspects of print quality that affect in-store scanning. "Traditional" methods measured printed bar widths to a specified tolerance but this had little or no correlation to the actual end-use scanning experience. ANSI has become the impartial basis for meaningful communication between producers and users. Furthermore, ANSI measurements show not only if a bar code is acceptable or "good" but also how good, or how close to "bad" it is. Thus, an ANSI bar code verifier — especially when used in-line — is a process control instrument in addition to a quality audit tool.

An in-line ANSI verifier reports quality parameters in real-time with instant feedback to the press operator. When quality degradation is detected, press adjustments can be made before any unscannable codes are printed. Besides reducing waste by detecting process problems early, in-line systems increase efficiency by speeding up make ready because bar code verification is done automatically on the press.

Until recently, in-line bar code verifiers that performed the complete ANSI grade analysis were simply not available. That was because of the need for very high scan rates in order to "see" a bar code as it is moving, especially at speeds up to 1,200 fpm. Furthermore, to support such high scan rates fast signal processing is needed to perform the ANSI grade analysis in real time. Now, however, several manufacturers offer partial or complete ANSI grading for high-speed printing applications. Available systems vary in the speed, throughput and completeness of the ANSI analysis so an appropriate system may be selected for a given application based on performance and price from several vendors.

For variable printing applications, in-line measurement adds a new level of security by verifying both print quality and data content of every bar code produced. Missing, incorrect or duplicate bar codes are detected and the operator is alerted automatically. Now that the technology for in-line ANSI methodology is available to everyone, those who have adopted it are at the leading edge of bar code quality control.

About the author: Glenn Spitz is president of Webscan Inc, a manufacturer of in-line bar code verifiers that provide complete ANSI grading for high speed printing.

Glenn Spitz, Webscan, Inc.