Have you done a head soak/wet cap* on the Epson with Windex (that has ammonia)? We do a lot of sublimation, and occasionally have to soak the head to clear any clogs. I did get a couple used printers that the heads are clogged on though, and need replaced.

*Do a nozzle check, and while the head is on the left side, squirt some windex in the capping station (we have a syringe with some tubing to do this). Wait half an hour, and do a head clean, then test it again.

Otherwise, we're looking for a color laser printer too.