I am trying to set up my iMac to print to my Epson XP520 printer. The printer is connected to the router but my iMac is not, I have disconnected the USB lead do I have to disconnect the Ethernet cable as well
Whilst you're not likely to want to connect by both USB and wireless, I think you'll find the printer drivers loaded would be slightly different for each connection. Therefore, if you have a "USB" driver loaded but disconnect the cable, it won't print wirelessly. Similarly, if you have a "wireless" driver loaded and turn wireless off on the Mac, it won't print using a USB cable. (When adding a printer, the Mac will load the relevant driver depending on how it finds your printer i.e. you deleted the USB driver so when you added the new one, it connected wirelessly so loaded a wireless driver.)
Thank you for your post on wireless printing. I did reinstall the printer drivers after I had removed the USB cable, but the Mac still didn't show it as connected until I reinstalled the printer in system preferences
You don't need to install the drivers as a separate task - when you add a printer in System Preferences, if there's no driver installed it will offer to install it.
Douglas Cheney 