Fill an A3 sheet with cyan squares. Print the sheet and stop it when the sheet just gets past the transfer roller (you will need to bypass the door interlock). Pull out the process unit and look on the belt and drum to see where the image is blurred. If it is ok on the drum then you must have an issue with the transfer belt. If it has the same problem on the drum then it can either be drum, dev tank, charge unit or erase lamps. You can swap all these between colours to test. So swap the charge, drum and test. If the fault persists swap the magenta and cyan tank and do a print. The print should now be magneta. If you see the same problem clean the seal glass, then swap the write unit with another colour.
