The United State Postal Service (USPS) mail-processing center in St. Louis had just upgraded its sortation system to an automated tilt-tray system. However, that was only part of the answer to moving along mail to its final destination in short order. The system also required bar scanners capable of reading the bar coded zip code on each tote in order to divert mail to its proper destination.

USPS soon realized that it needed highly versatile bar code scanners to decipher the often poorly printed bar code labels. Not only was the print quality often light and difficult to read, but the high-density bar code could range in size from a tiny 6 mil to an 11 mil symbol (1 mil = 0.001 inch). In addition, the bar code was enclosed in a cloudy plastic sleeve on the tote, making it difficult to read even the best bar codes.

To solve its problem, the Postal Service turned to fixed-position scanners. Due to the height and the quantity of the trays on the conveyor, each scanner needed to be mounted at an approximate 45-degree angle within 3 feet of the totes as they passed by. Moreover, the programmable sweeping raster enables the unit to scan the entire side of each on-coming tray.

Since the scanners have the capability to read a wide range of poor quality symbols, the USPS does not have to assign workers to handling problems resulting from misreads, saving labor costs while speeding items on to their destinations.