Why Verify Bar Codes?

Bar code verification is the most certain way to assure that you are printing good codes. The bar code, which began circa 1975, is virtually everywhere. You cannot find a product that does not have a bar code associated with it somewhere in its life. It is the least expensive and most reliable method of entering data.

Despite what some printer manufacturers may say, there is no perfect print process. Thermal printers may have ribbon wrinkles, burned out print head elements, improper heat and speed settings or a miss-marriage of the ribbon and face stock. Impact printers may have miss-aligned hammers or an over used ribbon. Laser printers may have fuser problems, low toner or a face stock that is improperly top coated. Lastly, ink jet systems contend with clogged jets, low contrast and differing substrates. With that being said, printers today do produce high quality print and any printer type, if properly maintained, will print good bar codes, most of the time. However, this may even make the problem worse. Knowing that the printer is likely to print a good code means that inspection becomes less appealing. Companies cannot afford to have someone do constant visual inspection and if they could the inspector would rapidly lose interest. This means that bar codes go unchecked. Enter the need for verification.

A verifier is not the same as a scanner. A scanner is typically a mass-produced item that provides machine recognition of the data encoded in a bar code symbol. Using a scanner to read a bar code only assures that the scanned bar code has some region on it that is readable, by that scanner. Therefore, the better the scanner, the less bar code quality assurance is maintained. A verifier, on the other hand, is a precision instrument that is made to predict how well the bar code will be read by the typical scanner, any scanner. It should decode, measure and check formatting of even the most inferior symbol and indicate area(s) that are deficient so that corrective action may take place.

There are two methods of bar code verification, traditional and ANSI. Traditional verification analyzes how well the code was printed. It looks at parameters such as print contrast, absolute element widths and average bar deviation. ANSI verification predicts how well a scanner incorporating a particular wavelength of light and a particular aperture size will read a symbol. ANSI looks at eight criteria: edge determination, minimum reflectance, minimum edge contrast, symbol contrast, modulation, defects, decodability and decode. It does this by taking a scan reflectance profile of the code and analyzing that profile.

Where should a verification system be placed? Verification should take place right after or during the printing process and before the bar codes enter the system. If you are printing bar codes for others to scan, you should verify with the philosophy that any bad bar codes should be reprinted. If you are receiving bar codes from others, you should verify before letting bar codes into your system.

Why should verification systems be put into place? Verification should be done to ensure that the bridge between printing and scanning is accurate, to minimize faulty scanning and to ensure that inferior codes do not enter the system. Inferior codes cost time, productivity and money. If a code does not read at all there is a return to the slow, error prone manual data entry and this causes bottlenecks or may stop enterprise critical applications. If the code reads after several attempts there is a waste of time and a chance of repetitive movement injuries. And, if a code reads with errors then there is a contamination of your database.

What industries need verification? Every industry that has a high cost associated with printing bad bar codes should have a verification system in place. Let’s face it, if the cost of printing a bad bar code is non-existent or minimal there is no need to check the code. However, the converse is also true. If by printing a bad bar code you receive fines, potentially lose business, have to do costly re-work or have other potential high cost repercussions then a verification system is warranted. Many industries need verification systems. Suppliers to major retail chains need to avoid getting fined for non-readable bar codes. People printing bar codes directly onto corrugated materials need to ensure readability of the code against low contrast. Printing companies providing bar codes printed on press and imprint houses providing bar codes printed on printers can avoid costly re-work of jobs by implementing a verification system. Medical and pharmaceutical suppliers need to ensure properly marked product to avoid dispensation of incorrect materials. Chemical companies need to ensure properly marked product to avoid costly fines and law suits. Suppliers to the automotive industry need to ensure labels meet the AIAG specification. Suppliers to the USPS should check the quality of their linear codes to meet the Postal specifications. Anyone running a highly automated warehouse that uses scanners to route packages can avoid bottlenecks and stops by putting a verification system in place. Many industries should have verification systems due to substantial repercussions for printing bad codes.

One last thought, if you are spending thousands of dollars on an AIDC system with labeling, data collection, inventory control or the like, shouldn’t you ensure that the bar codes for that system are able to be read?