Black Toner Feed Issues - Xerox C400

[EnSee]

Having issues with black printing
Coming through *very* faded

Started when issue with waste toner being full

Now replaced

Black was very low

Have replaced with a couple of new carts

Had issues with 092-321 errors

Have carried-out the resintall of relevant carts and drums
Including using the cleaning rod on all drums

And vacuuming the toners. Lot's of waste toner about

Any thoughts gratefully received.

Cheers

NC