Troubleshooting Zebra GK420t label printer printing past the label end. Includes calibration, sensor checks, and maintenance steps for retail environments.
Movement can dislodge the sensor or cable connections.
Using the incorrect label type can cause printing issues.
Regular cleaning is crucial for optimal performance.
Label printers utilize optical sensors to detect gaps or black marks on labels, signalling the end of a print job. Sensor misalignment, contamination, or failure can lead to inaccurate label detection. Firmware controls sensor sensitivity and label registration. Voltage fluctuations or electrostatic discharge (ESD) may impact sensor readings and logic controller operation.
Safe Handling: Always disconnect the printer from the power source before performing any maintenance or cleaning. Ensure the power outlet is properly grounded to prevent electrical shock. Avoid contact with the printhead, as it may be hot during operation. Static electricity (ESD) is a risk, especially in dry environments. Ground yourself before touching the printer.
Regularly clean the label sensor with a lint-free cloth and isopropyl alcohol. Use high-quality labels to minimize adhesive residue buildup. Protect the printer from dust and debris. Provide cable strain relief to avoid loose connections.
Some Zebra printers have a 'Media Type' setting within the printer's configuration menu. Ensure this is set to 'Gap/Notch' or 'Web Sensing' if using labels with gaps, or 'Continuous' if using continuous media. Access the configuration menu by holding the feed button down during power-up; consult the Zebra GK420t documentation for precise steps.