Simplest way to align rectangular boxes

[Butters]

I'm working on a design of packages opener but first I need to figure out how to feed them neatly into my machine. What's a common industrial way to take rectangular shaped boxes from the buffer with transporting belt so that all boxes would enter the next stage aligned longitudinally one by one?

 

[Astronuc]

On a belt or roller conveyor system, it would seem one needs have some kind of fixed protrusions that can ensure the boxes are aligned ostensibly along the major axis, such that boxes align toward the perpendicular would be reoriented and aligned appropriately, then guided by a narrowing chute to the machine.

Is the concern only with boxes sitting on the bottom face and the only need is to rotate them horizontally?