Externally added charge control agents (EA-CCAs) were prepared by means of a coacervation process. Spherical silica particles of 100 nm average diameter were coated with two kinds of charge control agents (CCAs); one was a polymer type P-1 and the other was a low molecular weight type P-2. Both of CCAs made remarkable contribution to toner charge. In a concentration range up to 0.2 μmol/g of CCA on toner, toner charge increased. From the relationship between the amount of EA-CCA on the toner and the tribocharge, P-2 was found more effective than P-1. It was estimated that 0.7 mol% of P-1 repeating units and 1.3 mol% of P-2 molecules contributed to toner charge, respectively. Calculation of the surface coverage of P-2 on spherical silica particles showed that the efficient concentration region of charge agreed with the 100% of surface coverage. The P-2 concentration was 0.02 μmol/g based on toner. This means that the CCA molecule has a great effect on tribocharge in small concentration.
Koichi Tsunemi, Atsushi Suka, Takashi Iimura, Kazuki Nakamura, Norihisa Kobayashi, Toshihiko Oguchi, "Toner Charge Control With Externally Added Charge Control Agent Particles" in Journal of Imaging Science and Technology, 2011, pp 50604-1 - 50604-5, https://doi.org/10.2352/J.ImagingSci.Technol.2011.55.5.050604