HP printers with clogged print head nozzles often do not print with black ink. Therefore, cleaning the print head is a resolution that some HP printer users have confirmed to correct printing. Note that you may need to do this several times to fully restore print quality.
The way to clean a print head may vary slightly between different HP printer models. HP printer not printing color is a common issue. Generally, you can select a Deep Cleaning or Clean Printhead option from the Printer Maintenance menu on the control panel of an HP printer. Selecting that option may print a page showing pattern output for multiple colors.
Therefore, make sure there is some paper loaded in the printer before selecting to clean the print head. Consult your printer manual for more specific details on how to clean your print head.