Thanks for your thorough explanation. Makes it easier to trouble shoot and get right to the point of figuring it out.
I think it would benefit if you sent these into Technical Support at InkjetMall, 17 Powder Spring Road, Topsham, VT 05076
Please add to these,
- Calibration Mode print out of the Inkseparation file for each printer.
- 21 step grayscale print on paper with correct Piezography curve for each printer
(please confirm the 21 step is at 5% increments before printing).
1) From above we can check integrity of your inks.
2) The blotchiness looks like to me that your carbon printer possibly has settled pigment as its printing darker in the mid-tones and 1/4 tones. Probably elsewhere, too. We would measure the density of the 60% patch for each of the inks.
2) If the inks are darker - then why? Age, contamination from mis-filling cartridge, mis-filled bottle (very very rare but possible), sitting in printer? Have you tried removing the carts and shaking them, reinserting and running the INITIAL FILL to freshen the ink lines and dampers with ink?
3) If the inks are okay in the cart (densities correct) - then it gets more difficult to trouble shoot. Perhaps your print head is decaying. Perhaps a re-linearization of your curves using the new QTR .quad linearization droplet will work, or a custom curve. Perhaps a fresh install of both the Epson printer driver and QTR will help. If the inks are correct, you may have to look in strange places for a fix. The 7880 is worth the rebuild. It has a significantly longer print head life than the newer Epsons. But that's only after exhausting whether your ink system is confirmed.