One thing that sort of puzzled me having a Epson print head in my hand was watching an ink bubble form on it out of the blue. Like it just appeared out of the head all by itself and not hooked up to the printer at all. Only 1,300 prints so who knows: Air? Heat? Funky head?
If a blob remains under there, or to one side due to lint, paper fibers, hair, dust, whatever it can cause problems. Some of my ink on the side of the retaining shield around the head had a gummy mess of ink that resisted even alcohol, but ink cleaning solution got rid of it.
I did note on mine, where the head's carriage broke loose and was dragging the head over the paper, that paper fibers built up in the little thin frame that holds the head on - right at the union of the frame and head on both sides of that frame piece. Lots of ink was in those fibers and maybe provides a wick for the blobs to form? Hopefully the wiper knocks them off. I had to use a Q-tip and ink cleaning solution to wipe them off in that area. The stuff is like black Vasoline.
I dunno, but Canon and Epson seems to have differing opinions on their ink firing technologies. I don't seem to read a lot of Canon ink blob messes over Epson, but could be more Epson issues in forums too.
SG