Streaks of Missing Ink Appearing on Label – Thermal Printing Problem

Target Audience: Basic User
Article #: 9798


Thermal transfer printers use heat to transfer ink from a ribbon on to the surface of a label. Problems with the print head can cause gaps or streaks of missing ink or ribbon material to appear on the label.

Situation and symptoms

  • Printer has previously printed labels without the streaks
  • One or more streaks of missing print on the label
  • The streak of missing print runs the length of the label, going from front to back as it exits the printer.
  • The streaks get wider and more numerous over time
Product name and part of the ingredients unreadable due to ‘streak’


Something is interfering with the print head’s ability to make contact with the ribbon to melt the ink and transfer it to the label. That these streaks of missing ink are straight and consistent, running from the front to the back of the label typically indicates that the problem affects only specific parts or elements of the print head. Likely these affected elements have either mechanically failed or there is residue on the print head that blocks the element from heating the ribbon.

Elements of the print head may fail by wearing out or other damage to the print head surface. Or, as in the case that prompted this article, residue had built up on the print head, preventing it from heating the ribbon sufficiently to print.


If the print head element(s) have failed or something has damaged them, then the print head will need replacement. Some print heads can be replaced ‘in the field’ (i.e. by the user) while some require a service technician to replace. Contact your hardware supplier for pricing and information.

To resolve the issue of residue on the print head, the user must clean the print head. Users will find most thermal print heads easy to clean. Thermal printers typically use a spring loaded latch to allow the user to open the print engine and expose the print head. A cotton swab moistened with standard isotopic alcohol will clean most foreign residue from the print head.

Sato CLNX Internal View

Additional comments

Issue Found: Sato CLNX

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