Epson not completing print

I have two printers running off one computer, a DX8400 for general print/scan/copy and an R285 for slightly nicer work, photo prints etc.

Now neither of them are working: if I try and print a document only about a third prints then the printer just stops and sits there. After a few minutes a 'non connection' message comes up.

I've uninstalled and reinstalled both. Same thing.
I've uninstalled and reinstalled only one . Same thing, (after one print done ok).
(Uninstall complete, not just in 'Add Remove', all files cleared. ..although I didn't check the registry to clear it of all Epson.)
I've checked for updated drivers.
There's no Device Manager indication of any fault, printer or usb, (they run through a hub. I've tried direct connection, same thing).
Inks all ok. No blockages showing.
Thought it might be some sort of memory thing so checked my RAM which seems ok.

Any clues please?