Patent ID: 8579775

Claim:
A supply roller of a developing device for an image forming apparatus, comprising: a shaft having an outer diameter of about 4.0 mm to about 6.0 mm; and a conductive resilient member enclosing an outer circumference of the shaft, wherein the conductive resilient member has a density of about 80 kg/m 3 to about 120 kg/m 3 , and an outer diameter of 8.0 mm to less than 10.0 mm, said conductive resilient member being obtained from a polyurethane, a conductive additive having a terminal hydroxyl group, a blowing agent, and a silicone surfactant, wherein the conductive additive comprises a polyalkylene glycol having a molecular weight of 300 to 3,000, wherein the polyurethane is prepared by reacting a polyol and a polyisocycanate in the presence of a catalyst.