Software RIP for Epson Laser (C4100)

Hi,

My company bought an Epson C4100 and as we got grey pattern on some
pictures, we were told we had to buy a RIP for it (on a memory chip).

Now the problem is it costs nearly the price of the printer itself ! If
we knew !...

We previously had a C2000 printer and I suppose the RIP was included
because we didn't have to spend extra money to print our document.

I know there exists software RIPs but I can't find any for Epson laser
printers, only for inkjets.

Does such software exists ? If not, why ? That's just data conversion
after all !

Thanks.

PJ