Origin Version (Select Help-->About Origin): 7.5 Operating System: Windows XP
In a "Page Setup" window of "File" menu the values of default margins are established at 25 mm for Top, Right, Bottom and Left. It is too much - resulting images hold too much blank space. I can not introduce smaller values as the corresponding windows are desactivated.
Printers have limitations, so there will be some small margins that are not printable. On a graph window, Origin does not really care about the Page Setup settings, you can move the layer to be as close to the paper edge as you want. What you can do is to draw some boxes near the edge and see if they can appear in the printed page. When you see something not printed, it is due to the printer's own limitation, namely its printable area.