Barcodes are a vital part of supply chain, inventory, and asset management applications. They are a cornerstone of improving efficiency in the enterprise — that’s why poorly printed, damaged, or otherwise unreadable barcodes have a huge impact on a business.
An ounce of prevention is always worth a pound of cure. To prevent unreadable barcodes, first make sure your barcode printers are well-maintained, cleaned, and are used with the correct consumables and labels according to manufacturer specifications.
If your company still struggles with unreadable barcodes, it is likely because of a number of fairly common reasons, listed below. Fortunately, all of them can be easily resolved by fine-tuning your barcode printers or adopting industry best practices in your printing and labeling processes.
1. Low Contrast: Barcode scanners must be able to successfully differentiate between the light (spaces) and dark (bars) elements of a barcode; that’s how the scanner decodes the pattern in the barcode. Unreadable barcodes may not have enough contrast between these elements, and the scanner won’t be able to read the code. If a printer does not uniformly produce light and dark elements across the label, this can result in low contrast. Variation or “noise” in the label substrate, or even harsh shadows or reflections caused by lighting can also cause no-reads.
Solutions: First make sure you are using label substrates that aren’t highly reflective and that offer enough contrast to the barcode itself. Adjust your printers to ensure that ink is evenly applied, and ensure your barcode reading equipment provides adequate lighting. Imaging-based scanners used to read 2D barcodes also have much higher tolerance when it comes to contrast, so using this type of equipment can help improve your scan rate.
2. Quiet Zone Violations: Each barcode includes a “quiet zone,” or an area surrounding the code that has to be free of text or other marks. This helps the scanner distinguish the barcode from surrounding material. The quiet zone is generally a minimum of 10 times the width of the narrowest bar of a 1D barcode; 2D codes require an area at least one element width on each side. If other marks or text intrude on the zone, it may result in an unreadable barcode.
Solutions: Each symbology has a slightly different quiet zone requirement. Adjust your printing process to meet those specifications. If necessary, increase your label size and make sure your printing equipment isn’t generating unintended marks on the label. In particularly space constrained applications (for example, marking small electrical components), high-performance scanning solutions are available that can tolerate less-than-minimum quiet zones.
3. Damage or Distortion: Printing a readable barcode doesn’t guarantee that the label will remain readable. As marked items pass through manufacturing or shipping process or are exposed to the environment, the barcode can become damaged, faded or distorted. The label may be scratched, torn, or shrink/change shape because of exposure to moisture.
Solutions: While you can’t prevent all label damage, you can mitigate against the effects of damage and distortion by choosing a printing method, ink, adhesive, and label substrate combination that can withstand your operating conditions.
There are substrates, print materials and adhesives designed to withstand abrasion, exposure to sunlight, or high levels of moisture without being damaged. ARMOR’s AXR EL thermal transfer ribbon, for example, is specially designed to provide sharp, durable barcodes on electronics and printed circuit boards that are resistant to soldering and cleaning processes used in that industry.
Certain types of barcode symbols are also designed to be readable even when damaged — a Data Matrix 2D symbol can be read even if as much as half the code is damaged.
Most barcode scanning issues can be easily remedied by using the approaches outlined above. There are other reasons that barcodes can’t be read, which are addressed (along with helpful solutions) in Part 2 of our blog on unreadable barcodes.