Only color ink is printing

[SoxCat]

Although all my ink levels are full or at least half full, my HP Envy 5640 is only printing in color. No black ink is printing. I have gone through the menus to clean the cartridges, clean the heads but nothing has worked. I get a sense that perhaps the print head for the black cartridge is blocked or died. I really don't want to replace the printer since the colors are still printing perfectly.  Help!

[Bob_Headrick]

The Envy 5640 has cartridges with the printhead integrated with the ink supplies.  Replacing the ink cartridge will also replace the printhead.  I would suggest the following:

• Get a clean coffee cup and put 1" of hot (not boiling) water in the cup. 
• Put the black cartridge in the cup with the printhead facing downward (as the cartridge would be in the printer).
• Let the cartridge soak for fifteen minutes.
•  Remove the cartridge and dry the electrical contacts with a lint-free wipe.  A clean coffee filter works well for this.
• Blot the printhead on a damp tissue.  At this point the cartridge should give a strong blot of black.
• Replace the cartridge in the printer and try printing.  Run a cleaning cycle if needed.

If the black cartridge still fails to print properly and the cartridge did not give a good blot of ink after the soak then the cartridge should be replaced.