After replacing the Lexmark E120's printing drum, you'll need to reset the system to ensure that the drum counter is reset to zero. This gives the system an accurate reading of the drum's current level, and helps it to remind you that the drum needs replacing next time. Resetting the E120 is only a matter of opening a panel and pushing a few buttons. The reset process takes between 60 and 90 seconds.
Grasp the sides of the Lexmark's front door. Pull the door down as if you were going to replace the drum.
Push and hold the "Cancel" button on the Lexmark's control panel. Continue holding the button until you see the system lights flash.
Push the front door back into the "Closed" position. Push the "Continue" button. The Lexmark's counter is now reset. You can continue with your print job.