Oki PT390 Manuel D'utilisation page 22

(3) Adjust the separator to the width of the roll paper. For roll paper
with a width of 80 mm, the separator need not be removed. For roll
paper with a width of 70, 60, or 58 mm, remove the separator and
attach it again at the correct width. For roll paper with a width of
83 mm, remove the separator completely.
Note: At the time of shipment from the factory, the separator is set at a position
appropriate for a paper width of 80 mm.
How to remove the separator
From the location indicated by A, lift the separator.
20
Rear hook
for the axis
Separator