Since I've been working at home I just noticed I think for the first time in two years my PRO-4000 woke up on its own, cleaned itself, and immediately went back to sleep. No network or power disruptions or any application activity that would have triggered it to wake up. I always leave it turned on just in case, but I was beginning to think it never did clean itself except before starting a print job. It's been 3-4 weeks since the last thing I printed on it.