ATM (Automatic Teller Machine) adopts mechanical principle of the turning over the page of the bankbook, using the friction by pushing and rotating the robber roller on the page of it. The shape of the rubber roller affects the drive torque and the performance of rolling up the paper significantly. In this research, an experiment with the model of the robber roller is conducted. And the state of contact between the papers and the rubber roller, the torque of the shaft ,and the height of rolling up the paper when the rubber roller rolls are studied. Some data for the optimum shape of roller are obtained
