It sounds as if you're relying on the Epson printer software/drivers. Printer descriptions would show up if you're using postscript printing software.
1. Try creating pdf's and print those, it may go quicker.
2. Is it only Quark or does this apply to other applications?
3. Either that or try and find the latest printer drivers from Epson.
Are the labels using complex line art or placed high res pictures? Are you using placed jpg's instead of tif's? As an aside, unless you're using postscript printing software, placed eps artwork will have the "jaggies" in Quark.