Oki ML5521 User Manual page 50

2. Grasp the tabs and lift off the sheet guide.
3. Pull up on the lock levers to release them.
The movement of the left tractor (as viewed from the front of the printer)
is restricted to ensure that the paper covers the paper out sensor.
4. Move the left tractor to the position to match your paper size
and push back on the lever to lock it in place, then move the
right tractor to fit the width of the paper. You will find reference
marks (1 in illustration below) on the printer for the two most
common paper sizes:
1
NOTE
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