How do you have things set up in the print driver?
My Epson 2200 has the "maximum size" option which I always set. The result on matte paper was that everything was centered with about 1/8" margins all around if the image proportions were right.
With the Z3100 there is always about 3/4" across the bottom of a 8.5x11 or a 13x19 sheet that I thought I was stuck with. Ron... can you explain the Standard, Oversize and ClipContentsByMargins that I had never seen before (the HP explanations do not make much sense)... i.e. is it possible to get rid of that 3/4"?
Sorry for the lazy desire to not run a bunch of tests