For some time, GAF Materials Corp. had palletized bundles of roofing shingles and wrapped them with paper. But a move to shrink-wrapped bundles made it painfully obvious the marking system previously used was entirely inadequate.

Actually, there had been problems with its readability. The printed codes were not clear enough to read beyond five feet. In addition, the wrong codes were frequently printed on bundles.

"The next person to see the mistake was the forklift driver, but that was after 30 minutes when 15 pallets had gone by," says supervisor David Ortiz. "That was a loss of time and money. Because of this and other inefficiencies, we decided to change over to an ink-jet marking system."

Now, software simplifies the selection and printing of the right code on the right bundle. All workers have to do is scan a bar code from a menu. This signals the ink-jet printer to print the new codes on each bundle. This process reduces errors in code selection.

Other benefits include improved marking legibility and easier maintenance of the equipment. Having a printing system all in one box keeps maintenance simpler, according to Ortiz. In addition, production speed increased 6%, partly due to fast drying ink, which permits palletizing of bundles directly after printing.

"Also when we made a color change of bundled shingles, it would take too long to make the conversion," Ortiz continues. "On the older system, this involved changing the print heads."

Now a color change can be made within one minute. A new, rack-mounted printing controller with 16 drop-on-demand valve printheads is easily cleaned for color changeovers. One button controls the cleaning of four printheads at a time. Previously, each head had to be cleaned individually, which made the color changing process last three minutes.