Patent ID: 7797833

Claim:
A method of producing a developing roller comprising a mandrel, a resin layer on an outer periphery of the mandrel, and a surface layer on an outer periphery of the resin layer, comprising a step of curing a mixture containing a carbon black, and the following components (a) and (b) and forming the surface layer: (a) a diol obtained by a reaction between a polytetramethylene glycol having a number-average molecular weight of 650 or more and 1,000 or less and 4,4′-diphenylmethane diisocyanate, the diol having a weight-average molecular weight of 8,000 or more and 12,000 or less; and (b) an isocyanate compound obtained by a reaction between a polypropylene glycol (PPG) having a number-average molecular weight of 700 or more and 2,000 or less and polymeric diphenylmethane diisocyanate, the isocyanate compound having an isocyanate group at least at any one of its terminals, and the isocyanate compound having an average number of functional groups of 3.0 or more and 3.5 or less and a weight-average molecular weight of 25,000 or more and 60,000 or less.