I believe it cleans the heads. You will also waste some ink when changing from one black to another. My 3880 is about a month old now, so I'm learning as well.
I'm not sure about that...I spend a lot of time in the same room as my 3880. I've never heard it do a spontaneous mini-clean. Though, if left on and idle for a while, it seems to do a quickie-clean before printing.
I've always heard that it is not a good idea to leave a printer on if no printing is to be done. If it is going to be idle for an extended time I would make a small print at least once a week.
Photrio.com contains affiliate links to products. We may receive a commission for purchases made through these links. To read our full affiliate disclosure statement please click Here.