Oki PT390 Manuel D'utilisation page 44

Using the cleaning sheet or a similar material, wipe off the adhesive
matter adhering to the Lower cutter.
Lower
cutter
Note: Although the edge of the Lower cutter is not as sharp as the edges of utility
knives generally used in offices, there is a risk of injury to a finger that is
moved while pressed directly against the edge of the cutter.
(5) After completing cleaning, reposition the roll paper, and close the
Top cover.
Note: Be careful when the printer is in cutter cleaning mode, because the Upper
cutter is exposed. After completing cleaning, reposition the roll paper, and
close the Top cover.
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