Image Number 3 for United States Patent #6129301.
A drive roller for a belt-driven tape cartridge is molded of composite polymeric material in a single step to include outer segment and inner segment integrally formed together with a radial web segment between the outer and inner segments to provide highly concentric operating surfaces on the outer segment and in the inner segment. Electrical conductivity throughout the molded drive roller is provided by including in the composite material a quantity of carbon powder, and selective shrinkage of the composite material during cooling from molding temperatures provides desirable bearing surface within the inner bore through the inner segment. Thrust bearing surfaces at the ends of the inner segment engage mating bearing surfaces that include lubricant traps to inhibit migration of lubricant away from the bearing surfaces of the drive roller. Stepped inner bore and axially ospaced corresponding stepped axle diameters promotes lower frictional drag, provides a reservoir for lubricant, and facilitates removal of the molded component from its molding cavity.