User guide

99
Troubleshooting
Print Quality Problems
8/4/10 GX420t / GX430t User Guide 980612-001 Rev. C
Print Quality Problems
No print on the label.
• The media may not be direct thermal media when printing without ribbon (i.e. thermal
transfer). The media may not be direct thermal media. See the test procedure Determining
Thermal Media Types on page 39.
• For thermal transfer printers, the media may not be outside wound or approved for use in
the G-Series printer. See the following ribbon test procedures: Ribbon Test with Adhesive
on page 42 and Ribbon Scratch Test on page 43.
• Is the media loaded correctly? Follow the instructions for Loading Roll Media on page 15
in the Getting Started section. For printing using transfer ribbon, see Loading Transfer
Ribbon on page 19.
The printed image does not look right.
• The printhead is dirty. Clean the printhead.
• The printhead is under temperature.
• Adjust the print darkness and/or print speed.
•Use the
^PR (speed) and ~SD (darkness) commands referenced in the ZPL
Programming Guide.
•Use the
D (darkness/density) and S (speed) commands in the EPL Programmer’s
Guide.
• Manually adjust print darkness with the six-flash sequence of Feed Button Modes
on page 106.
• The Windows printer driver or application software may change these settings and
may require a change to optimize print quality.
• The media being used is incompatible with the printer. Be sure to use the recommended
media for your application, and always use Zebra-approved labels and tags.
• Verify that the printer power supply in use is rated at 100 Watts of DC output.
• The printhead has worn out. The printhead is a consumable item and will wear out due to
friction between the media and printhead. Using unapproved media may shorten life or
damage your printhead. Replace the printhead.
• The platen may need cleaning or replacement. The platen (driver) roller maybe losing
traction due to:
• Foreign objects attached to its surface,
• The rubbery smooth surface has become polished and slippery, or
• There is damage to the normally smooth and flat print surface such as box knife cuts.