printing different fonts from command line

[brian.hunter at ma-biznes.com]

I'm using a TSP600 printer on SuSE Linux 9.2. I want to be able to print either a different font or a bold one.  My text output is very poor(not dark enough). The driver setting are Normal,Good,Best... but no difference between them.
Is there a way I can set the printer to use a specific font by default?
or
What command can I issue from command line to make it work?

cat $receipt | lpr -Ptsp600 ...

thanks