I've had this problem before but cant remember what I did to put it right. When I print anything the print disappears off the right hand side of the document but there is still a margin.
If it's a wide page you could switch the printing instructions from portrait (ie up and down) to landscape (ie page prints sideways)? When you click on print you should get a prompt come up that says 'preferences' or something like that, where you can change it.