Oki 490 - Manual (Page 21)

Using Your Printer 21
To adjust the gap, open the access cover and move the blue
lever (1) to the recommended setting from the table.
Setting Media
1 Regular paper
2 2-part form (with carbon)
3 3-part form (with carbon)
4 4-part form (with carbon)
5 Envelopes or extra thick paper
Note: When the head gap is set to 2, 3, 4 or 5, the printer
automatically slows down for better print quality with
multipart forms.
Printhead Gap
The printhead gap is the distance between the printhead and the
platen.
CAUTION!
Make sure the printer is turned off before you open the access
cover.