Did you remove the printhead from the printer and cleaned it ?
Thanks, ***** *****'t know, how will you react on my honest answer, because the problem you are facing can be caused by two reasons, one if the printhead is dirty or if it is defective. As you have already cleaned the printhead without any positive result, it means the printhead is defective and thus the solution for your problem is replacing the printhead.
No problem, but Lexmark will give you the same answer, because no one can repair a defective printhead. Anyway, as you wish, please do not give any rating, as you think I did not help you by telling you the printhead is defective.