Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
It is possible that you have a defective black cartridge. Consider changing it out for a new one - especially if there has been an interval of disuse of the printer recently, and most especially if your printer is an HP brand printer, there is a likelihood that the change of cartridge will get the black ink working again.
(Is the black not working when you do a photocopy, as well as when you print from the computer? if so, it is definitely a problem in the black ink section of the print engine inside your printer, rather than a software problem on the computer or that sort of thing.)
I may have other advice to offer, so let me know - esp. if your printer is not HP-made.
(If this by chance answers your question fully, please rate my answer. Thanks.)