Print density mottle in solid black electrophotographic printing was shown in a previous report to be strongly linked to the distribution of PCC fillers in paper. A model of toner transfer showed qualitatively that toner transfer efficiency is locally increased in regions of high filler density. In this report we extend the previous work by quantifying effect of filler distribution and of paper calliper variations on toner transfer in electrophotography. We modeled the complete electrostatic force field structure within a paper-air-toner transfer gap during electrophotography. By relating effective local dielectric constant to filler concentration, we computed the difference effects that surface and bulk PCC fillers have on the local toner transfer force field. The toner transfer force was found to be higher when the PCC filler was distributed homogeneously throughout the bulk thickness rather than localized at the surface of the paper. Quantitative model of in-plane variations in toner transfer force as a function of corresponding in-plane variations of the effective paper dielectric showed that the variation in paper dielectric on the scale of 500μm or larger contribute significantly to toner transfer force variations. We also found that the higher filler content amplified the effect of caliper non-uniformities on the toner transfer force variations.