A described example includes a ribbon cartridge having a first spool housing to receive a first spool. The ribbon cartridge further having a second spool housing to receive a second spool. The ribbon cartridge further having at least one frame member extending between the first spool housing and the second spool housing and a spool lock, wherein the spool lock is configured to engage at least one of the first spool or the second spool in response to the ribbon cartridge not being received within a ribbon positioning assembly.