I have had a similar problem. Twice now after replacing the (three) color cartridges the black printer head temporally stopped printing, at all. The printer ink level diagnostic indicates the black cartridge is near full. After a couple of days to a week the black printer head starts working again. My wild guess is it has something to do about how the printer charges the print heads after changing out a cartridges, in this case affecting the black print head, repeated cleaning of the print heads only wastes the color ink. I am presently using three 1X size color cartridges with one 2.5X black cartridge, although I haven't read anywhere that this would cause a problem.