Hi,
Most probably could be from cloged toner in the dispenser system.
And pay attention at the part no for the toner. There is a part for VersaLink C7000 (just printer) and another one for VersaLink C7025/7030 (MFP).
Gabi
I had once a VersaLink with black dispenser assy that didn't mesh properly with the dispenser motor.