An apparatus and a method of ink jet printing are disclosed that use a system for feeding a substrate longitudinally relative to a support area and a system for moving a printhead parallel to the direction of substrate feed. Some embodiments of the invention also include a split chute for transferring the agricultural produce from the fill hopper to the produce tray and a trolley for selectively positioning the split chute under the fill hopper or tuck finger platen. The increased thermal conduction through and out of the gallium nitride devices enhances operability of the devices, including providing excellent RF operation, reliability, and lifetime.