I'm also having the problem. I'm using a Mac Mini, Yosemite and the printer is plugged in directly to the computer with USB cable. This only happens after about 25-50 scans. I then not only have to turn it off but have to wait at least 15 minutes or it will happen quickly again.
If this is happening to people using various OS and connections, it appears this is either a hardware or software issue you need to pay attention to.