This document specifies a method for the determination of the apparent hardness of vulcanized- or thermoplastic-rubber roller covers, expressed in Shore hardness, for measurement where only medium precision is required. The method and apparatus used are essentially those described in ISO 48-4, the measurements in this case being made on the curved surface of the conditioned rubber-covered roller rather than on a flat test piece. Shore type A and type D instruments are specified, the latter being used for measurements on rollers of high hardness.
NOTE With some rollers, there can be significant variation in the thickness of the rubber over the surface of the roller, which could affect the measured apparent hardness.