A separating roller includes a sleeve having a first hollow cylinder, an arm protruding from an outer surface of the sleeve, a shaft assembly having a middle section, disposed inside the sleeve, and two ends on two sides of the middle section, a torque limiting element and two friction rollers. The sleeve and the shaft assembly are hung from a body by the arm. The torque limiting element coils around the middle section and contacts the shaft assembly, and is accommodated within the first hollow cylinder. One portion of the torque limiting element is fixed to an inner surface of the first hollow cylinder to provide a limiting torque to the shaft assembly and to limit rotation of the shaft assembly. The friction rollers are respectively fixed to the two ends of the shaft assembly. Each friction roller has an outer diameter greater than that of the sleeve.