I would not suggest printing from QTR or any program with nozzles that are clogged. This can short them out.
You most likely need to replace the damper that goes into the print-head. This can get air-locked and over time will also clog. The internal epson documents say this part needs to be replaced every two years. We replace this every year with our printers at IJM and so far have run our 7880s for 8 years straight.
Do a google search for "epson 9880 field repair guide" for documentation on this procedure. compassmicro.com sells the dampers.