Pinching belt conveyors are widely used in mail sorters, automated ticket gates, ATMs, and so on. In these conveyors, two belt-roller systems are pressed each other by lifting one of the systems, and media like posts, tickets, or bills, are pinched and transformed by the two belts running together. The roller, around which the two belts wrap together, is called a key-roller. Traveling distances of the belts and medium in the conveyor are investigated by experiments and computer simulation. The

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... esults show that ( 1 ) the traveling distance of the driving side belt is always constant, while that of the driven side belt largely increases or decreases as the increase of the lift of the belt-roller system. ( 2 ) The traveling distance of the driven side belt is larger (or smaller) than that of the driving side belt when the driven side belt wraps around the outer side (or the inner side) of the keyroller. ( 3 ) The traveling distance of the medium lies between those of the two belts. ( 4 ) The above ( 2 ) and ( 3 ) are not always realized when an additional roller is set in the lifted belt-roller system or furthermore when a medium thickness and difference of friction coefficients of the medium surfaces satisfy certain conditions.