I just got a used HP Photosmart C5280 from my father in law. There is a problem with the black ink, though. Sometimes, it doesn't print and when it does, it's not really black. An example can be seen at the following link, where I created three black boxes on a Word page and printed. The outcome is somewhat blueish:

Other tests with black text only come out as blank pages.

I have tried using the print head cleaning utility from the menu of the printer as well as doing the cleaning myself with alcohol. Nothing has worked.

Any ideas before I throw out the black cartridge?