If you have a PostScript printer whose manufacturer’s drivers are not available or are questionable, there is another way. Adobe (inventor of PostScript) has for a long time made a complete alternative printer driver engine available:
http://www.adobe.com/support/downloads/detail.jsp?ftpID=1505
and the OpenPrinting folks have PPDs (definition files) which often work with the above. In a recently-visited case of Oki C6000 for XP, we have:
http://www.openprinting.org/show_printer.cgi?recnum=Oki-C6000