I just recently bought an Epson R3000. Printer works great except if I try printing at max quality (5760 dpi) and set PS CS6 to print landscape mode. At this setting, it just continuously prints garbage ASCII characters blowing through several sheets of paper. It seems to put the printer in some weird state where I can't even cancel the print job by pressing the garbage can button on the printer.
I did some poking around and looked at the resolution settings for each quality mode. So at the highest quality, it's 5760x1440. Level 4 quality setting is square at 1440x1440. Printing at level 4, it prints. Level 5 (5760x1440), I get garbage characters printing. I'm guessing this has to do with me setting PS to landscape mode which I guess conflicts with the resolution setting. If I set PS to print portrait, level 5 5760 dpi mode works just fine.