If I create a Microsoft Word document the Page Setup - Margins Tab allows me to set any margin to Zero - top bottom / left right.
This suggests that the printing width is determined by the application and limited by the size of the paper.
If you have Word you can drop the image/text onto a Word Document and play around with the margin setting.
If you go for full width printing and if the paper is slightly misaligned you may end up with a white stripe on one side and missed printing on the other.
Peccavi, February 2009
