most printer suppliers will sell you a RIP software along with your machine. if not they should at least advise you on whats best suited.
some will offer a few options like Wasatch, Onyx, Versaworks etc
if your machine is a roland printer then the RIP comes free and i would suggest using their own as its a very good and easy software to use. that and the fact its purposely made for their machines. not forgetting you then need the profiles for the printer in question to run with your software. if you bought the machine second hand ide suggest asking the seller why there is no software? i don’t mean that they must sell you the software just that it is a necessity and would have thought they would have given you the software for the machine, tried selling you it for extra or even advised you on it.