I have had this printer for a few years with minimal problems. But, now the PGBK250 ink cartridge will not print. When I print a normal b/w page I get nothing. For a while I was getting a light blur of the text, now I am getting nothing. I have tried to clean printheads, and the deep clean printheads commands. Following which I print a print head alignment sheet, but there is no print coming from the pgbk printhead.