Hello,
we have this issue with the printer in question. Sometimes when we power on the printer, the touchscreen stays completely black and doesn't seem to be getting any power. This seems to happen completely random. When the screen works, it will stay on untill you restart the machine once again.
Sometimes it can take hours, even days of restarting the machine to get the touchscreen working again. Sometimes we even have to unplug the machine for hours in order for the touchscreen to start working again.
Moving the screen and tapping it doesn't do anything. There is no flicker or anything.
Edit: I should also point out that printer itself works fine if the touchscreen is blank. It prints, but things like copying and scanning is nearly impossible without the touchscreen.