Error printer bin full

This is an error when it senses there are too many pages that have been printed and are sitting in the bin.

Take a close look at the flaps hanging out the exit for the printer. They should move up and down freely. If one of them is stuck up, broken or dislodged, you'll get the bin full error. The flaps on the other end (side you can't see) have little flags that sweep between photo sensors and tell the printer in the tray is full and if paper has exited the printer into the tray