Tip - HP 6500 Office jet E709a - Black printer cartridge HP 920 not working

My blck ink is not out, the panel shows that it's about 2/3 full. But it won't print anything black. I turned the printer off and back on, and I remmoved the ink cartridge and put it back in. I don't know what else to do.
Tags: Print Quality, Ink Alerts, Cartridge Rejection, Page Yield, Printhead Errors, Cartridge Problems, Color not printing, Black not printing, Cannot install cartridge, Need printhead, Cartridge compatibility