Why does the turning roller convetyor choose tapered roller?

The conventional belt conveyor and roller conveyor adopts striaght round roller while the curved belt conveyor and turning roller conveyor adopts  conical tapered roller. Why is that? 

This is because the conventional straight conveyor line transmission process does not need to turn, it is only need along the straight line transmission. But turning conveyor transmission needs to have a radian, so the roller is made into a cone, in order to make the object on both sides of a speed difference,  so that the object can follow the turn.

The radius radian of the turning conveyor is small, the radius radian of the outside is large, the arc of the roller is not the same at both ends, and it needs to be finished in the same time, so the speed is not the same. The linear speed of the big head is smaller than linear speed of the small head by the same motor speed, which makes the speed difference,  the speed of the big head around the slow speed of the small head rotation, forming a difference turn.