Are you printing from Mac or Windows? What version operating system? If Mac, are you printing from Photoshop, QTR Print Tool or a different application? When did you last print and have good/correct output? Have you replaced dampers in this printer in the past three years?
After reviewing your order history, I see you last bought a set of Piezography Neutral inks in June 2009, so your inks are nearly five years old, and well past the expiration date. Using such old inks could be most if not all of your problem.
Please let me know so I can help you past this and back to happily printing.
Best regards~ Dana