US Patent 8439293 Paper dispenser

A dispenser for dispensing paper from a dispensing roll located in a lower dispensing position has a guide track which leads from the top into the lower dispensing position and in which a standby position, defined by a blocking device, for a reserve roll is provided. The dispenser further has a device for detecting a diameter of the dispensing roll and a device for releasing the blocking device for the reserve roll once the paper on the dispensing roll has been used up. The diameter of the dispensing roll is detected by a sensing element which pushes against the circumferential surface of the dispensing roll, is displaced by the dropping reserve roll and returns to its sensing position once the reserve roll has dropped.