officeet pro6970 doesn't print cyan

[brex]

my HP OfficeJet Pro 6970 does not print blue.   color comes out pinkish.   Ran Devise reports<Print Diagnostic Report and CYAN does not print.    Replaced all instant cartridges about 2 weeks ago.   Could it be a bad cartridge or printer problem? 

[Gooomer]

You already replaced the inks so it means the problem is your printer printhead (the one that carries the inks and moves from left to right). It's no longer absorbing other ink colors. 

[brex]

thanks for info.  what is the fix?  replace print head or?    how difficult is it to replace head?

thanks