While the following comments are based on the Star SP542 receipt printer, they probably apply to all printers in the SP5xx series.
The Star SP542 receipt printer works well with Koha and Firefox on Windows XP SP3. This printer, with either the parallel or USB interface, is fairly easy to install and configure. You will need the following executable file which is available from numerous places on the Internet:
This executable actually does all of the installation; you will not need to use the Microsoft Windows "Add Printer" program. We recommend that when installing, the option for the software monitor not be selected; we have experienced significant pauses and delays in printing with it. Instead, simply choose to install the receipt printer without the monitor.
Additionally, the install program may not put the printer on the correct port, especially if using the USB interface. This is easily corrected by going to "Start -> Printers and Faxes -> Properties for the SP542 printer -> Ports", then check the appropriate port.
A reboot may be required, even if not indicated by the installation software or the operating system.
Windows 7 users should refer to this page: http://www.starmicronics.com/supports/win7.aspx.