How conveyor belt head pulley works?

A Conveyor belt's head pulley is also known as the drive pulley, its on this end of a conveyor system where the motorized pulley is installed. At this point the conveyed material is discharged "wherever" and the belt wraps around and begins its return cycle.

The head pulley is at the discharge so that the conveyed material is "pulled" through the system vs. having the tail pulley motorized which would be forcing the system to "push" the belt containing the conveyed material.