Phillip Corcoran :
I don't know how long your printer was left unused whilst waiting for the new printhead to arrive but it's possible that the remaining ink in the unsealed cartridges has dried to a paste instead of being liquid and is therefore no longer able to flow through in to the printhead.
This is even more likely to occur if the inks are solvent-based as opposed to being pigment-based, since the solvent component evaporates relatively quickly.
If that's the case, a set of new cartridges should do the trick.
Thanks for the reply. I had found a blue cartridge that had solidified, the first I had ever seen, and replaced it, and then later, all the OK others one at a time, but it's still the same. I have ordered new ones and will be try that set when they arrive. Ink is being taken from the cartridges when doing a head clean as the levels change. Neither colour or black printing work. Not very optimistic just now.