Hi IM la Verne - Many thanks your trouble but what I'm surprised at is it's not had heavy use or been neglected or abused and I've not had any smudged or faint printing - absolutely no warning - do they really go so quick, so unexpectedly and so under used? By the way, in case its of interest...
MP780 has been used with IJT compatible inks for at least 2 years with no problems but suddenly freezes and displays 'wrong cartridge' blinking error. I removed and replaced printhead but then feed switch would not select rear 'auto sheet feeder' which machine says it needs to align printhead...