HP Laserjet 4015 Maintenance

Reset the Maintenance Kit:

1. Turn the product power off and then on.
2. When memory count appears on the control-panel display, press and hold down the OK button until all three control-panel lights flash once, and then stay on. This might take up to 10 seconds.
3. Release the OK button and press the up arrow to scroll to NEW MAINTENANCE KIT.
Press OK to reset the maintenance-kit counter.

http://h20564.www2.hp.com/hpsc/doc/public/display?docId=emr_na-c02420672