De-agglomerated hydrophobized fumed silica is compared to corresponding traditional agglomerated fumed silica as an external additive for electrophotographic toners. The first finding is that the Tribo-Electrostatic Charge (T-ESC) of toner treated with de-agglomerated silica is as strong as that with traditional silica after agitation. Charge distribution analysis however indicates faster charge-up for de-agglomerated silica. These characteristics apply for both milled conventional toner and chemically produced toner and are explained by the superior dispersibility of de-agglomerated silica. The shelf-life (storage stability) was also tested and demonstrated that de-agglomerated silica maintained performance under normal appropriate storage conditions.
Yuki Amano, Naohiro Naito, Steffen Hasenzahl, Robert Johnson, "Comparison between De-agglomerated and Traditional Fumed Silica External Additives and Their Performance in Toner Formulations" in Proc. IS&T Int'l Conf. on Digital Printing Technologies and Digital Fabrication (NIP25), 2009, pp 32 - 34, https://doi.org/10.2352/ISSN.2169-4451.2009.25.1.art00012_1