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Print Quality Problems
70
P1052686-001 GC420t™ User Guide 5/22/2012
There are long tracks of missing print (blank vertical lines) on
several labels.
• The printhead is dirty. Clean the printhead.
• The printhead elements are damaged.
The printing does not start at the top of the label or misprinting of
one to three labels.
• The media may not be threaded correctly. Follow the instructions for Loading Roll Media
on page 11 in the Getting Started section.
• The printer needs to be calibrated. Refer to the two-flash sequence of Feed Button Modes
on page 76 in this section.
• ZPL Label Formats - The correct media sensor may not be activated. Manual calibration
selects the media sensing method for the labels being used (refer to the
^MN command in
the ZPL Programming Guide).
• ZPL Label Formats - Verify that the Label Top (
^LT) command is correctly set for your
application (consult the ZPL Programming Guide).
• EPL Label Formats - The correct media sensor may not be activated for label dispensing,
blackline or notch sensing, or for Gap/Web sensing. Manual calibration selects the media
sensing method for the labels being used (refer to the
O and Q commands in the EPL
Programmer’s Guide).
• EPL Label Formats - Verify that the Set Label Length (Q) command is correctly set for
your application (consult the EPL Programmer’s Guide).
A ZPL label format was sent to, but not recognized by, the printer.
• Is the printer in pause mode? If so, press the Feed button.
• If the status LED is on or flashing, refer to What the Status Light is Telling You on page 66.
• Make sure the data cable is correctly installed.
• A communications problem has occurred. First, make sure that the correct
communications port on the computer is selected. Refer to Connecting your Printer to a
Computer on page 22 in the Getting Started section.
• Verify the correct Format and Control Prefix on the printer match what you are using in
your ZPL programmed label format. The default Format (COMMAND CHAR) is Caret
(^) character and the Control (CONTROL CHAR) is a Tilde (~) character. Verify the
characters with the Configuration Status label printout. Refer to the one-flash sequence of
Feed Button Modes on page 76 to print this label.