Sorry, I think I didn't explain it well.

The Print Preview looks fine, but when I press the Print button in the lower left of the Preview window (shown in your screenshot), the text comes out tiny.

The odd part is that when I use the Print button from the Print Preview screen on my system I get just the document (with small text), but when I tried the online demo you provided, the printout contains the Print button, the Width and Height fields and the Cancel button, along with a header line which contains the date and page name.