HP3070A printer problems

[MedusaIsHavingABadHairDay]

My black ink won't print! Ink levels fine, even put a new cartridge in..all the other colours print, just not the black. I have tried a print clean with no result.
The printer is only 7 months old but of course I can't find the receipt and when I spoke to Currys they were not helpful.

If anyone has any suggestions, I'd be grateful!

I know this thread is old, but have been having the same problem and wondered if you found a solution?

We've had the printer a little while and have no idea where the receipt is. It worked absolutely fine until the original started inks ran out, and then I replaced them all with brand new hp cartridges and the black now doesn't work at all.

I've run the clean print head programme several times, and the alignment test - and have consequently almost run out the colour cartridges, which I'm seriously annoyed about - but still no black ink printing.

Anyone got any ideas??