wp-print question

I installed the wp-print.php add-on. Seems to work fine except for one minor thing… I adjusted the font size down because I’ve never liked 12pt type.
It displays the article in the correct font and size on the screen but when I print the page it comes out in the ‘ol TimesRoman 12pt default.
I thought it might just be a browser thing (probably is) and so I tried it with Internet Explorer (I use Firefox) but got the same results.
Can anyone clue me in on why it blows-off the specified font?
Thanks,
Matt