Try a Gutenprint driver for the Brother but I think you are out of luck with the Oki:
<http://gutenprint.sourceforge.net/p_Supported_Printers.php>

I imagine it is possible if you have a network where you share printers through a PC on the network but, with the price of printers, I would think it is time to retire the Oki.

That's progress!

regards,