After reviewing your order history, I see you last purchased Piezography ink and R2880 refillable cartridges from us in Nov 2012, is this the ink and carts you're using?
Have you cleaned the printer's capping station, wiper blade and bottom of the print head following our cleaning procedures? If not, you can find our helpful cleaning/maintenance procedures here: http://www.inkjetmall.com/tech/content.php?133-Printer-Cleaning-and-Preventative-Maintenance
Have you had good results with this printer, ink and carts, then recently started having troubles getting a good nozzle check? What channel is not printing at all? When was the printer last used and working well? How often is this printer used vs. how long does it sit unused? It's possible that your carts don't have good ink flow anymore due to age, and you would benefit from getting a new set of carts (we recommend getting new carts about once a year for the best results). What are the humidity and temperature levels in your printing environment?
There is currently no way to adjust the Platen Gap in the R2880 with QTR, and I'm not sure if Roy Harrington plans to add that in the future (you can certainly ask him directly). Are you experiencing head strikes on the top or side edges of the German Etching paper, or in the center as well? What size sheets are you printing on? Fine art papers often curl towards the print side, which can cause the print head to touch or scuff on the paper. We recommend flattening paper before printing, which you can read more about here: http://www.inkjetmall.com/tech/content.php?148-Flatten-Curled-Paper-Before-Printing
Are you feeling paper thru the top/auto paper feeder, or the front or rear paper feed slot? We print almost exclusively on heavyweight papers with our desktop and pro model printers, and have great results as long as we keep the printers clean and make sure the paper is flat before printing.
Please let me know, thanks~ Dana