As Screen printers we need a good 17″ wide film printer and usually Epson delivers excellent printers. The Epson 4900 is a good quality printer, yet it has earned a reputation as a printer that clogs more frequently than most other models. Reports are that the Epson inks (pigment) may be a big part of the issue. Using dye inks such as the All Black Ink system or Dmax ink for refillable systems may help prevent or reduce clogs as compared to other inks.
It is well advised to maintain your printer and keep your service contract up to date even extending it when possible. Seems that issue arises with most users after the first year, just in time for the service contract to expire.
Freehand has a powerful yet low cost liquid clog busting formulation called Amaze-Ink available in this web store. If you have a clog you can follow the video instructions in the Video Library about Amaze-Ink and wide format printers.