I have a HP photo smart C5380 all in on printer

I have been printing out some posters for a friend today the first few were really good then suddenly all the colours were wrong and the photos came out a bit blurred and horrible colours. Checked inks black and photo black were a little low so replaced still not different.
I have alligned the cartridges and cleaned the head and no joy still the same.
Anyone have any ideas how I can correct this please.