Oki PT390 Manuel D'utilisation page 36

Then, press and hold down the FEED switch for one second or
longer to accept the selection. The printer enters platen roller
cleaning mode. The printer prints the following and cuts the
paper when it enters platen roller cleaning mode:
PLATEN ROLLER CLEANING MODE
1. Open Cover, and remove Roll Paper.
2. Push FEED switch to move
Platen Roller to the cleaning position.
3. When cleaning is completed, set
Roll Paper, and close Cover
(3) Open the top cover, and remove the roll paper.
(4) Press the FEED switch to rotate the platen roller to a position
that will facilitate cleaning, and then wipe the platen roller with
a dry soft cloth to remove paper particles, adhesive, and other
foreign matter from the surface of the platen roller.
Platen roller
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