Well, first of all, you need to be sure that your source images are of sufficient resolution. On that printer, your minimum image resolution is going to be about 240pixels per inch.
If you print to PDF using the same settings, and then you zoom in on the PDF, does it turn pixellated too soon?
Also, from my Epson-owning days, I can tell you that printing at 1440dpi looks just as good as the 2880dpi mode, but takes a lot less time to print. Heck, even 720dpi "Photo" mode is practically indistinguishable.
tooki