Solution
In most cases, a defective photoconductor unit causes toner streaks. This is especially true if the streaks are of only one color. To identify which photoconductor unit is defective, go to the printer’s Configuration Menu and print the Quality Test pages. To do this:
Power off the printer.
Press and hold the 2 and 6 buttons simultaneously.
Turn on the printer.
Release the buttons after ten seconds. The printer should boot up to its Configuration Menu.
Select Print Quality Pages to start printing. Confirm whether the print quality issue you are experiencing can be seen on the printed pages.
After printing, scroll down and select Exit Config Menu. The printer should restart in Normal mode.
One of the printed test pages should show four horizontal bars with colors black, magenta, cyan, and yellow. See which colors show horizontal marks. Replace the photoconductor unit corresponding to that marked color. If the streaks appear on all four colors, contact Lexmark Technical Support for other troubleshooting suggestions.
Other suggestions
If replacing the photoconductor units does not correct the issue or if you have no replacement supplies in stock, please try the following suggestions: