This article discusses the effect of silica concentration on transfer of nominal 8.5 μm diameter surface-treated toners, with the silica concentration on the surface of the toner varying between 0 and 2% by weight of toner. In essence, it was found that, while transfer efficiency increased with increasing silica concentration, resolution decreased and dot structure after transfer was degraded. Toner adhesion measurements, performed using an ultracentrifuge, were found to correlate well with the transfer efficiency measurements. Analysis of the results suggests that the adhesion and cohesion of toner is dominated by van der Waals interactions. However, electrostatic forces associated with the charge on the toner become more significant with increasing silica concentration with the two types of interactions becoming comparable when the silica concentration reached 2%.