Hi John~ I was getting ready to call you, but may be able to get this sorted out right now on the forum for free (and cancel your phone support order).
If the printers print with the Epson driver, but no ink prints with either machine when printing from QTR, then I'd say the printers are working (you're not dealing with a clogged head, etc...), and it seems to be somehow related to QTR. Please clarify- are you saying the printers act like they are printing, but no ink actually gets on the paper? Or- do you get an error when you send a print job and can not print from QTR?
I recommend cleaning and reinstalling: delete the Epson print driver and QuadTone RIP (both the RIP and Print Tool), then download fresh copies from the Epson and QuadTone RIP sites for fresh instillations. After installing the fresh Epson driver, QuadTone RIP and QTR Print Tool, shut down the computer and printer at the same time. After about a minute, turn the printer and printer both on again. Confirm connection by printing a nozzle check from the Epson Utility. This is to test 1. connection and 2. nozzle check quality (you should have 7 full sections of Piezography inks). Provided the nozzle check prints correctly, move forward (but if it doesn't- check your connection and try again). Open a grayscale image in QTR Print Tool, select your Quad7600-K7 printer model, push print to go to the QTR print window, select the curve for the paper you're using, QuadTone RIP mode, your desired resolution + speed, and NO adjustments made to the ink limit or gamma settings.
Please let me know so I can help you get back to happily printing.
Best regards~ Dana