Lexmark Optra E 4026-0 Series Reference Handbook page 103

Auto Clean Frequency
This can be set from 10 to 255 pages with a default of 50. Auto Clean
Delay does not appear on the menu unless Auto Clean is on.
1. Enter Diagnostics mode.
2. Select [Auto Clean Frequency].
3. Select [+] or [-] to display the frequency desired.
4. Select [SAVE].
5. Press RETURN to return to Diagnostics mode main menu.
Defaults
U.S.
Letter size paper
# 10 envelopes
Symbol Set Roman-8
To set the defaults:
1. Enter Diagnostics mode.
2. Select [Defaults].
3. Select [U.S.] or [Non U.S.].
4. Press RETURN to return to Diagnostics mode main menu.
Developed Image Test
Use the Developed Image Test to isolate print quality problems. You
might have to practice this procedure several times to get the timing
correct.
To run the Developed Image Test:
1. Open the front exit tray.
2. Print the test page.
3. As soon as the leading edge of the paper is visible coming out
the front exit slot, turn off the printer.
4. Remove the print cartridge and look at the image on the
photoconductor.
5-10
Laser Printer Reference Handbook
NON U.S.
A4 paper
DL envelopes
Symbol Set PC-850