I am getting the same problem with a Lexmark X1180 All in one.
It worked fine for over 4 months and then all of a sudden there is NO black!!!
I have tried reinstalling the cartridges, replacing them with new, reinstalling the drivers - ALL TO NO AVAIL!!!
It works every time fine for colour!!
It is the same when photocopying - a black copy is blank, a colour copy is spot on!!
Can someone please suggest a fix as this is driving me mental!!
Cheers the now,