HP 4500g. Black is very misaligned with other colors. Cannot resolve.

After working well for many years, this HP 4500g began printing black misaligned with the other colors. The three color component is aligned, but the black ink appears with a significant off-set. This came on after I used a third party set of ink cartridges. None of the HP tools purported to fix this sort of thing have worked. Any ideas welcome. This was a nice printer, and all the newer HP printers seem to be pretty bad, so I’d rather not downgrade. Thanks for the help! }8^}