Unchanging Partial Black Clog

I have an Epson 7600 which, until a heat wave, was working perfectly.
Then, the MK (black) ink ran low, and we had swap in a very old ink cartridge until new ink arrive.
And, the printer cooked in a hot room. And, maybe even some air got into the lines.

So, now, the MK bottom-most nozzles will not clear, no matter what I do.

  • Window/Piezoflush/water wipe with paper towel.
  • Many times I have “puddled” the head park, with water, PiezoFlush, Windex, and even some nasty chemicals from American Inkjet .
  • I have even connected the Piezoflush kit for pushing the stuff through the head with a syringe, and I pushed (and pulled) gently sending at least 30ml through.
  • Finally, tonight, I put some of the Piezoflush in a cart, sucked the black out of the line, and let it feed into the head. It is now sitting, and I’ll let that hang out for a few days.

IF ink is really frozen in those lower channels, at what point do I stop messing around and …

  • Take off the head and soak it (I’m afraid of doing that and not being able to put it back on and adjust it properly)
  • Buy a new head for $400
  • Enter the insane asylum for Epson large format owners…

Here is the nozzle test; showing the bottom-most nozzles clogged (remember, the paper feeds top down):

Thank you.