each time i need to scan with the cannon dr-1210C, a pop up window appears saying that it's warming up. I understand that machines need to warm up if not used for a while, but even if i just finish scanning an object and begin to scan the next, the "warming up" pop up window appears. Also, when it finishes scanning, the images show 2 dark vertical lines. I've tried manually cleaning the machine with soft, damp cloths as well as with compressed air; neither of which work. Please Help!