Hi guys, forst of all sorry if my english is not perfect

Im started using ubuntu two months ago, and now im trying to switch my office's pc to ubuntu too.

Everythings works perfectly, the only problem i have is with the printers: i have 4 Epson usb printers, 2 R285 and 2 P50 linked to my pc.

Those printers works, but seem like ubuntu consider them as 2;

Printer A: Epson P50;
Printer B: Epson P50;
Printer C: Epson R285;
Printer D: Epson R285;

So, the first P50 i switch on is the one ubuntu see: if i switch on the A printer, ubuntu will print with it and completely ignore the printer B and viceversa, the same happen for the C and D printers.

I saw in system->Print->Printer A->Properties that the URI of the printers are the same for the model, so printers A and B have that URI:
usb://EPSON/Stylus%20Photo%20P50
C and D:
usb://EPSON/Stylus%20Photo%20R285

and i think that this is the problem.

There is a way to 'map' the printers, for example 'Printer A from the USB port #1, Printer B from USB #2, etc...'?