INKJET PRINTING OF BARCODES

Inkjet has opened a new world of possibilities and solutions for barcoding—and a list of new problems to be solved and prevented. Inkjet works so well with many applications, this can lead to overconfidence in its capabilities. Overconfidence can lead to complacency, especially in maintenance. Frequent cleaning prevents a common problem with inkjet printing: dirty print heads and clogged nozzles. Streaks or missing bars quickly and effectively kill barcodes.

Lithographic and flexographic printing directly contacts the substrate. You know immediately if there is a problem with ink smudging or drying, especially on non-porous substrates. Inkjet is non-contact—you can produce hundreds of images before you know there is a problem.

Inkjet images can also be inconsistent. This is a serious problem with barcodes. Bar and space width consistency is critical, as well as the location of bar and spaces. Inconsistency is difficult to track. Ragged or non-straight edges in barcodes are problematic. Voids in bars or artifacts in spaces cause scanning problems.

Other print technologies experience gradual changes in image quality over relatively long periods. This is well known in flexographic printing: the plate temperature increases over time. As the temperature builds, the plate expands, increasing pressure against the substrate and spreading the image. It is a gradual process.

Inkjet inconsistency can be gradual—for example as ink viscosity changes over time. But it can also be sudden. If transport speeds are variable, or if the gap from the print head to the substrate changes, or the substrate shifts randomly, one barcode can be acceptable and the next one a failure.

Temperature and humidity are a factor in inkjet inconsistency, especially with drying times and smudging.

Inkjet solves the problem of inserting a barcode at the last stage of a packing process—for example, applying a barcode with a serial number or expiration date. But it can be difficult for inkjet to place the barcode in a designated location precisely. A slight lateral shift can violate a quiet zone and cause a scan failure.

Inkjet is a marvelous imaging technology, capable of doing things traditional printing cannot do. Eager inkjet representatives know more about selling than printing. Ask for barcode samples. Trust and verify. And that goes for the equipment once you own it—trust and verify. We can help.