Zebra Thermal Printer Print Quality Troubleshooting

There are a few common issues/repairs on the Zebra thermal printers. The printhead and platen are both parts that wear out with use and can be damaged by well-intentioned but uninformed end users and improper maintenance.

One of the most common things to come across my bench is a platen that has been cut up by an end user removing media with a razor blade. Never use a razor blade to cut labels off of the machine. Another common issue with platens is uneven wear across the platen due to using media that is not the full width of the platen. This can lead to poor print quality due to uneven pressure across the printhead.

The easiest issue to diagnose is a cut platen, even if a cut is small it can lead to voids in print as the cut can cause a loss of pressure at the print line. To check for cuts on the platen remove labels from the machine and perform a visual inspection on the platen by rotating it manually (while the printer is turned off). If you are not sure if there is a cut or just a mark on the platen, apply pressure with a fingertip and drag your finger perpendicular to the mark, if it is a cut you should feel it open up under your fingertip.

To determine if you have uneven wear on your platen, open the printhead and remove the labels. Simply place a fingertip on one end of the platen, and lightly rub your finger from left to right, and back again, if you feel anything that feels like a ridge or bump, then odds are you have uneven wear on your platen.

It is also possible for your platen to wear out from use without a ridge or obvious physical signs of wear. If you find yourself adjusting the toggle pressure on the printhead, or turning your darkness up, it may indicate that the platen is worn down.

If any of these conditions are met in your printer, it is necessary to replace the platen, as the printhead may be damaged, and print quality will be affected. For instructions on replacing the platen, please check out the video we have on our YouTube channel.

Printheads and print quality issues are also a common issue on thermal printers. It is common for a user to buy a printer that has a wider print area than the media the user needs. When this happens, it is possible for the edge of the narrower media to cause wear on the printhead. It is also common for wear to occur when the printhead toggle pressure is too high, or there is damage to the platen.

Wear mark on a thermal printhead.

The first step in diagnosing this is to clean the printhead. Simply take a small amount of rubbing alcohol on a paper towel, and wipe from left to right until the paper towel stops picking up ink from the printhead. Cleaning the printhead may solve minor print quality issues. The most obvious signs of wear are dead dots on the printhead, but often there are visual signs of wear as well, such as wear spots in the conformal coating of the print element. These visual cues can be obscured by ink buildup on the printhead, so be sure to clean it with a paper towel and rubbing alcohol before the inspection. Also, be sure to clean the printhead any time you swap out the ribbon or media, and any time you make contact with the print line of the printhead, as oils on the skin can reduce printhead life.

If you have dead dots or wear on your printhead, they can be replaced, however, a trained technician is recommended for this job, as the printhead may require mechanical alignment/adjustments to ensure proper print quality. 

If you have any questions, please feel free to contact MRP for more details.