Avery Dennison Monarch 9825 Operator's Handbook Manual page 84

You may need to clean the printhead, sensor, and platen roller:
♦ if there is any adhesive build-up in the supply path.
♦ after printing approximately 3 rolls of thermal
transfer/thermal direct/linerless supplies or
after each ribbon.
♦ daily if your printer is in an excessively dirty,
hot, or humid environment.
♦ when you see voids or streaking in the print
as shown.
When you are using increased print contrast, we
recommend cleaning the printhead after each
ribbon with isopropyl alcohol. If you still notice
build-up on the printhead or black streaks on
your supply, order a printhead CLEAN-STRIP.
1. Turn off the printer and open the cover and printhead assembly.
2. Remove the label roll and ribbon (when cleaning the printhead).
3. Press down on the exit cover tabs to open the exit cover on the front of
the printer.
Exit Cover
9-2 Operator's Handbook
Voids
Streaks