There is no optical drive in the current, "Late 2012" iMac models. If you need to install software only available on a disk, you'll either need another computer that does have an optical drive in which case you can use Remote Disk:
http://support.apple.com/kb/PH11203
or you'll need an external disk drive. Check with the printer manufacturer, though. They may well offer the drivers as a download.
Regards,