My TTWin 3 printouts don't use the selected font, why?

By default TTWin 3 prints in raw data mode. Raw data mode allows the print stream data to go directly to the Windows print spooler, bypassing most of the Windows printer driver. This is useful primarily when you are using legacy printers and the print data stream contains embedded codes specific to the legacy printer.

As a consequence things like font style and size cannot be manipulated by the Windows printer driver, as it has minimal contact with the print data stream.

If you wish to have control over the formatting of your printed output then uncheck the 'Print in raw data mode' option found under Configure > Preferences > Printer.