As far as I know, you need an ATX power supply if you want to be able to turn printer on or off. Here's an Instructable about it: http://www.instructables.com/id/Usin...ATX-power-sup/. I've been planning on implementing this on my FrankenCube, but as it's been working very well with raspberry + Octorint, never got around to it... just need to manually turn the ATX main switch off.