Granularity–density relationship for electrophotography incorporating paper and toner granularities

An equation to describe the granularity of an electrophotographic imaging system has been developed to include the density variance attributed to the reflectance of paper and toner surfaces. Granularity measurements from two conventional electrophotographic copiers were used to validate the relationship. The results show good agreement with the overall shape of the granularity-versus-density curve; however, the values are not consistent with estimated toner particle size. Clustering of the toner particles is suggested as the cause of the high granularity values.