I am going to copy and paste Dana’s response to this issue, we have the same problems in the studio and do not have the answers exactly to how to resolve this issue, there has been lengthy conversations regarding this exact complaint.
There have not yet been any solid answers to this strange problem, but some people have reported success when leaving about 3" margins on the side, so the printer sees white paper on both sides on the image as it passes over, and continues printing GO Over the entire sheet. Here is what I’ve been telling others recently:
[FONT=ArialMT]We have done extensive testing since discovering this issue, and gathered info from several customers using the x900/x890/x700 printers for Piezography gloss. We concluded the printer sensor is detecting what it thinks is the end of the paper when it sees dark ink area, and stops printing. There is no solid “fix” that is consistent and works in all cases, though some people have experienced success by printing a white image the full size of the paper they’re printing on (as you’re doing), leaving 2-3” white margins around the image (so the sensor “sees” white paper and doesn’t stop printing), and one customer feels he gets good results by selecting the 9800 printer model in his QTR window, but as I said none of our thoughts or customer reported “solutions” have been consistent or worked in every situation. This issue has been difficult to trouble shoot (and we’ve spent a great deal of time trying to figure it out), because results are random, and can not be duplicated from one printer to the next. I called and spoke to Epson to try figuring out how we can get the printers to print over an existing print, and they told me they’ve received many calls about this (because it’s always been possible up until these models), and it’s caused by the paper sensor on the print head. This sensor also controls other things like detects paper skew and size, as well as reads auto nozzle checks and alignments. The printer will not work if the sensor is removed or disconnected. I even tried tricking the sensor by applying a piece of white paper over it, but that didn’t work either. The only help Epson could offer is to suggest getting a new T-series printer, which doesn’t have this sensor, and is actually designed to print over prints- but, that’s not a realistic solution because those printers are MUCH more expensive. [/FONT]
[FONT=ArialMT]We are testing a new RIP that may be able to bypass the paper sensor, and provide consistent overprinting for these models. I’m sure we’ll be very excited to announce the results if it works as we’re told it will. Although getting a T-series printer is out of the question because of the expense (not to mention we don’t even know if it can be run by QTR or another RIP to have individual channel control), a good solution is to get a decent working 7800/9800 or 7880/9880, which have NO problems printing Gloss Overprint. It will speed up your production to have a separate printer for applying GO, and give you smooth, consistent results every time. We have six 7880/9880 printers, with five set up with different Piezography ink tones, and all print matte and gloss using the “P2” ink configuration- they are fantastic machines.
Best regards~ Dana [/FONT]
Here is the link to this thread I pulled this quote from http://www.inkjetmall.com/tech/showthread.php?35-problem-printing-GO/page6&highlight=Gloss+Overprint
We have tested the QTR TOOL she was referring to, with no results for consistent results on the X900/X890 platforms.