Recent data for some toners and carriers have shown that the tribo value is independent of the toner concentration. This is contrary to the conventional response in which the tribo value decreases as the toner concentration is increased. Since conventional models seemingly do not predict this behavior, new models have often been proposed to explain this effect. In this work we examine a toner:carrier pair for which the tribo value is independent of toner concentration. This result is obtained when separate developers are made at different toner concentrations. By changing the toner concentration using a technique which preserves the surface properties of the toner and carrier, we show that the conventional tribovalue: toner-concentration dependence is obtained and is consistent with the conventional models. The unusual behavior in which the tribo value is independent of the toner concentration is a result of changes in the toner and carrier surface composition when developers are prepared and mixed at different toner concentrations. Surface measurements of toner and carrier show toner-concentration-dependent surface modifications.
E. J. Gutman, R. S. Naumchick, A. M. Webb, "Why Does the Tribo Value Appear to be Independent of Toner Concentration in Some Two–Component Electrophotographic Developers?" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP15), 1999, pp 539 - 543, https://doi.org/10.2352/ISSN.2169-4451.1999.15.1.art00040_2