QTR-Quadtone RIP

I had banding in deep shadows. Nozzle check was quite bad for black.
Did a cleaning cycle, waited overnight and no change.  Status monitor
showed about 25-30% ink left in the black PK cart.

I finally decided to replaced the PK cart. Right after replacement, a 
perfect
nozzle check. Whew. No Windex and futzing required.

That said, does this indicate a "bad cart." After all, the cart was 1/3 
to 1/4
full?

Scott