Unlike the 3880 which will print borderless on some sheet sizes, I don't believe the 79/9900 printers support full bleed borderless printing on sheet paper, only on roll paper. You might be able to hack around, just oversizing might not work, you'll may also have to convince the printer it has something other than an 11" wide sheet of paper in it. So I'm not saying it can't be done, I've just never tried it myself.
Here's a quote from the spec sheet ...
BorderFree® Printing Left and right borderless “bleed” printing for the following roll media widths: SP7900 10", 13", 16", 17", 24" SP9900 10", 13", 16", 17", 24", 36", 44" Top and bottom edges can be automatically cut to any length when printing on roll media.
You cannot print the full length of sheet of paper, minimum I believe is .25" at top and .56" at bottom or something like that, so you can't print 14" on the 14" sheet paper. So to get the 11x14 you would have to trick the printer to handle the 11" borderless, and print on 17" paper then cut it to 14".