Abstract: A staging hopper for supplying packaging blanks includes a first conveyor positioned downstream of a second conveyor. The first conveyor supports and periodically transfers packaging blanks in a primary group of blanks to a blank delivery position. A second conveyor supports and intermittently transfers packaging blanks in a secondary group of blanks onto the first conveyor. The top edges of the secondary group of blanks rest at an angle against the primary group of blanks to define a longitudinal gap between the lower edges of the blanks in the primary and secondary groups. Photosensors are provided to detect the presence and absence of packaging blanks within the longitudinal gap. In addition to advancing the primary group of blanks, the first conveyor advances the forward blanks in the secondary group across the gap toward the primary group. The photosensors detect the presence of these blanks as their lower edges move across the gap.