Thanks for the response Guy1,
I was thinking there must be a micro switch or sensor that senses when that door is closed tightly, or not. Inspection of the collection bin doesn't show any wear or problems, and there is only a little toner in there.
Any guidance on the sensor/switch aspect? Before buying a new bin, I'd like to try cleaning the toner entry port on that bin. Does that make any sense?
Regards, and thanks again.