The point is, you don't need to refresh the page in order to print it with CSS: it prints the same page you are viewing, with some parts hidden.
for example, take a look at this:
http://telconet.moraphi.com/index.php?&a=1&b=0
Try to do a print preview on this page, you'll see that the login part, the breadcrumbs and the right-hand panel don't get printed. And it's exactly the same page.