Bar codes are technically nothing but special printing fonts. The best way to do is to install the bar code font on the print server and always print through SAPLPD via the print server.
Printing in a modern SAP installation should always be done through SAP standard print server SAPLPD. It is sometimes irritating since SAP also delivers printer drivers for most common printers; however, those drivers are SAP propriety and not designed by the printer maker; consequently there are often deviations in quality. As best-practice alternative SAP offers printing using standard TCP/IP LPD mechanism where SAP variation of LPD should be installed on the standard enterprise printer server.