Troubleshooting Common Scan Problems

ID Technology Guide to GS1 Barcodes

Barcodes are crucial for supply chains, logistics and product identification.

Do you sometimes have trouble reading a bar code with your, or your customer’s barcode scanner? Has your customer verfied the barcode and told you the quality isn’t good enough? It could be something simple, like holding the scanner incorrectly or mounting it at an incorrect angle, or maybe your scanner isn’t configured for the symbology you’re trying to read. What follows are some tips for solving common barcode scanning issues.

 User Error

Sometimes the way the barcode is oriented to the scanner prevents a successful scan. In this case, try the following:

  • Make sure the distance and angle between the scanner and the barcode match your scanner specifications.
  • Focus on scanning one barcode at a time instead of multiple barcodes on a package.
  • Be sure you are scanning the correct barcode if the item is labeled with multiple barcodes.

Scanner Configuration

Be sure the scanner is configured for the type of barcode you want to scan:

  • Laser scanners can only read one dimensional (linear) barcodes like the GS1-128. They cannot read two-dimensional barcodes like the GS1 DataMatrix.
  • Only imager lasers and camera orientation scanners can read 2D barcodes.
  • Make sure the symbology is enabled in the scanner for the barcode you are scanning. Check the minimum and maximum character settings and the scanner settings for that symbology.
  • Check that there isn’t a scanner setting that prevents your code scanning. for example, one scanner mnuacturer limits IFT barcodes to 8 characters, so the scanner will not read the IDT14 GTIN barcode that is common in the supply chain.

color coded lab labels - winco idMechanical or Electrical Problems

Maybe the scanner is not working correctly due to some mechanical or electrical issue:

  • Check the battery status if a mobile scanner. If there is less than 50% of the battery life remaining, change (or recharge) the battery and try again.
  • Verify that the scanner is securely plugged into the outlet. Also check the cord for wear or breaks, as this can interfere with proper scan operation.
  • Ensure that the scanner lens is clean. Smudges, fingerprints, or dust can impede scanning. Try wiping the scanner lens with a soft lens cloth.
  • Check if the scanner lens is scratched or damaged in any way. If so, it will need to be serviced.

Bar Code Print Issues

Sometimes it’s not the scanner that is the problem. The barcode itself might not have been printed correctly. Following are some problems that can happen when printing barcodes:

  • Ensure the printhead and rollers are clean – not cleaning these regularly is the biggest cause of poor print quality. ID Technology printer cleaning wipes are the best product to use for this.
  • If there are pixels missing from your printhead, you probably want to replace it.
  • Some barcodes (such as code39) require a special start character, a stop character, and most require a calculated check digit. Make sure the required format is being used to print the barcode fonts.
  • Try printing the barcode font at a different x-dimension size. Not all barcode scanners are the same; some lack the ability to scan all types and sizes of barcodes. Some scanners have a narrow reading width and cannot read long barcodes, while others cannot read small barcodes.
  • If the barcode appears to be truncated, increase the height and width of the field the font is displayed in so there is extra white space before and after the resulting barcode. Most barcodes require a white space around the printed symbol that is at least 10 times the most narrow bar in the barcode.
  • Check the print quality and DPI of the printer. Thermal printers that are 203 dpi or less are limited in the density of barcode they can print.
  • Make sure the material the barcode is printed on has proper contrast. Normally, the barcode should be black and the background white. Using other colors might cause poor scanning conditions. Also, make sure the material is not too glossy or the scanner light may reflect and not properly read the barcode.

Generally, if there is a barcode reading problem, it represents a failure at some point. A failure to print high-quality barcodes; a failure to specify the correct specification scanners or install them properly; failure to set up barcode scanners. If the barcodes you print are being used in your customer’s supply chain, it is hugely important that your printing is correct and to the required quality. See our article on Printing the Best Quality Barcodes to learn more.

Having problems with GS1 barcodes? Check out the ID Technology Guide to GS1 Barcodes. Since many industries use GS1 barcodes, an understand of the GS1 system will be helpful in getting your barcode printing and scanning operation working correctly.

 Do you want to get started improving your barcode printing and scanning?  Contact us today – 888-438-3242 Option#3 or you can contact me directly at We’ll get you in touch with one of our specialists right in your area.

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