Mozilla is using 'Times-Roman' font for printing preformatted and teletext text, where it should use fixed width font for those places. Open a page with texts having <tt> or <pre> tags. Observe that they're rendered with fixed-width font. Now print it (or save it to a file & open with ghostview). Mozilla uniformly used proportional width fonts. Same things happens when we open text/plain documents (RFCs, for example) and print them. Mozilla uses proportional font when it shouldn't.
Duplicate of "[PRE] Need support for printing preformatted plain text" *** This bug has been marked as a duplicate of 37685 ***