(1) Open the front cover, on the inside where the lights are there is a black button. Press the black button until all the LEDs are on. (The LED turns on in sequence from top to bottom.) The drum page counter is reset.
(2) Close the front cover, and check that the Drum LED is now off.
By doing this reset the black bar goes back to 100% and the drum count goes to 0 (zero) but the page count doesn't