Patent ID: 8045903

Claim:
A supply roller for use in a developing device to be incorporated within an electrophotographic image forming apparatus, the developing device having the supply roller and a developing roller disposed in a peripheral contact with the supply roller to define a contact region therebetween so that the supply roller is capable of supplying and collecting a toner to and from the developing roller in the contact region, the developing roller being disposed adjacent a photosensitive member of the electrophotographic image forming apparatus to provide the toner from the developing roller to the photosensitive member to visualize an electrostatic latent image supported on the photosensitive member, the supply roller and the developing roller being disposed so that the contact region has a peripheral width of 3 mm or more and 8 mm or less, the supply roller comprising: a core; and a polyurethane foam layer made of polyurethane foam including cells therein and covering the core to form a peripheral surface of the supply roller; wherein the polyurethane foam has an open ratio of cells of 2% or more and 50% or less and a hardness of 1 gf/mm or more and 6 gf/mm or less, the hardness being defined by a load per unit length in a longitudinal direction of the supply roller, the load being determined by forcing the peripheral surface of the polyurethane foam layer against a substrate, measuring a load necessary for the polyurethane foam layer to be compressed by 30% in thickness, and dividing the load by a length of the polyurethane foam layer in the longitudinal direction.