Currently Being ModeratedNov 25, 2012 1:12 PM (in response to ac1981)
Sounds a bit like it might be a Ground loop on the Printer.
Open Console in Utilities & see if there are any clues or repeating messages when this happens.
Currently Being ModeratedNov 25, 2012 1:44 PM (in response to ac1981)
Sounds to me like you are either disturbing the power to the Mini DisplayPort or actually moving the Mini DisplayPort plug causing it to lose connection
I suggest getting a Mac compatible 4 or 7 Port Hub to hot plug your printer and other USB devices into. That way you will not have to reach around to plug in USB devices and/or disturb other connections.iMac, Mac Mini, iPad, iPods, Mac OS X (10.6.8), (10.8.2), Safari, iTunes, iPhoto