Defining your needs - Verification

Simply stated, verification is the bridge between bar code printing and scanning. Verifiers can decode a symbol, measure key characteristics and grade the quality of the printed symbol to ensure that a bar code is in-spec -- and that it will read every time.

What type of guidelines will you use to verify your bar codes?
There are several ways to measure, grade and report bar code scannability and print quality:

• Traditional guidelines measure bar and space dimensions, print contrast and encodation.
• ANSI guidelines measure edge determination, minimum reflectance, symbol contrast, minimum edge contrast, modulation, defects, decode and decodability.
• Scannability Trend Index (STI) provides a report on print quality and scannability. The diagnostic data can help you decide if a symbol can be used in your system and, if necessary, can help you correct printing problems.

When specifying verification equipment, remember that a nonreadable bar code is not just an inconvenience. It's a potentially costly expense, particularly if you're printing labels for compliance applications. Many corporations -- including several of the largest retailers, automakers, utilities and electronics manufacturers -- levy significant fines on suppliers for out- of-spec or unscannable bar codes. A verifier that offers both Traditional and ANSI guidelines can be used to make sure you'll meet compliance standards with every label you print.

Will you require portable, desktop or on-line verification?

• Portable and desktop units can be pen-based or non-contact laser scanner based and are designed for hand-held operation. They can be used to verify symbols as they are printed or to verify bar codes that have already been applied. Although pen-based verifiers can be used for a variety of applications, non-contact laser units are preferred when verifying symbols on rough, curved and other irregularly-shaped surfaces.
• On-line verifiers automatically verify every bar code you print to guarantee 100% accountability. Mounted on the front of or within a printer, an on-line unit will examine every symbol as it is printed and stop printer operation or trigger an alarm if a bar code is unscannable or out-of-spec.

Reprinted with permission from Datamax Corporation - 2000

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