The problem occurs because of the trickle development system in the machine, making extended lengths of black and white copies / prints does not allow the black developer housing to purge itself of excess waste Toner (Dry Ink) and Developer. There are two solutions for the problem:
- Make 1,000 copies / prints of a black and white job, then make 150 copies / prints of full color. Continue making 1,000 copies / prints of the black and white job, then 150 full color, and so on, until the entire black and white job is complete.
- Make extended jobs in groups of 100 by making 100 copies / prints of the black and white job, then allowing the machine to cycle down (return to 'Ready') and making the next 100 copies / prints. Continue in this pattern until the entire black and white job is complete.
The above solutions are based on jobs using 8.5 x 11 inch paper, single sided, with no more than 28% coverage.