I have owned my Z3100ps GP Photo 44" for nearly two years come May, and have never experienced any poor print quality to speak of, until recently.
I was having a problem with the MK black on matte paper. It appeared to be a head clog, so I tried cleaning the print head using the printer utility to do so. I used a bit of ink cleaning and re-cleaning the print head, but the problem remained.
I spoke with HP tech support, their first response was that the printer was out of warranty. When I finally convinced them they'd never really heard from me regarding a serious issue with the printer, I was told that I needed to replace the print head. Considering that 97ml worth of ink ever went through it, I didn't really think it needed to be replaced.
So, I bought some BD alcohol swabs, they contain 70% alcohol and don't leave any residue behind. The swabs are really just 1 inch square pieces of alcohol-soaked intense weave cotton pads.
When I removed the print head, I immediately saw that there was a considerable amount of black ink goo (about a 1/4" or so) around all sides of the print head. I noticed a similar amount inside the print head holding tray.
I used the alcohol swabs to clean all of the built up gunk off the print head and from the print head holding tray. I cleaned the print head with a fresh one, did the same with the contacts in the print head holding tray.\
After reinstalling the print head and doing a required ink head alignment, I then ran one print head cleaning cycle and VOILA!
It works perfectly again.
Meanwhile, in looking around HP's web site - I found a ton of old links that don't work. So many in fact that I find their site completely useless. It's almost as bad as HP's convoluted telephone system.
I guess I should pull all the other heads and do the same - but my motto is usually "if it ain't broke, don't fix it".
Does anyone have any suggestions? Should I do the rest, or wait until a problem develops?