Epson 3880 hangs at 2% when swapping inks
I've recently been printing on photo rag using matte black and submitted a new print job through CS6 for Glossy paper. The printer started its ink change routine ("BLACK INK CHANGING MATTE -> PHOTO" on the printer control LCD display) and then counts up % completed. It started as usual at 0%, then 1%, then 2%, and then resets to 0% and starts counting up again. Each time it gets to 2% and then goes back to 0%. Ad infinitum.
What to do? Will I risk printer damage by turning the printer off, either by attempting to use the power button or by turning the power off at the power plug?
It's evening here and I cannot contact tech help for another 11hrs. Advice from users with experience of this problem on this model printer much appreciated.