I just got an Epson WF-3620 all-in-one printer last week, to replace an older Epson WF 600 all-in-one. Both of these printers use the same universal Linux driver; it is identified on the Epson website as the ESC/P-R generic driver, version 1.4.4.
With my older Epson WF 600, I had no problems with print quality. With the new printer, copies look great, and test pages are perfect, but when I try to print a document from my hard drive, I get something that looks like a draft-quality printout. Blacks come out pale gray, and anything less than black drops out completely. I've tried changing the media type from plain papers-draft to plain papers-high in Properties/Printer Options, as recommended to another poster with the same problem on forums.openprinting.org, but this didn't work for me.
I tried calling Epson, just on the off chance that I'd get someone familiar with Linux, but wasn't lucky this time. Epson officially doesn't support Linux. I managed after some effort to get them to tell me the procedure for adjusting the print quality in Windows and Mac, just in case I could extrapolate it to Linux, but the menus are completely different.
My computer is a Dell Inspiron 580s desktop. I am running Linux Mint 13.
If no one knows a fix for this, one other thing that would be helpful is any recommendations for other all-in-one printer brands that support Linux. Thanks.