US Patent 7118842 Charge adjuvant delivery system and methods

A system for printing a liquid toner is provided comprising a liquid electrographic toner composition comprising a liquid carrier having a Kauri-Butanol number less than about 30 mL and a plurality of charged toner particles dispersed in the liquid carrier, wherein the toner particles comprise a polymeric binder. The system also comprises a charge control adjuvant having limited solubility in the liquid carrier. The charge control adjuvant preferably is present in the liquid carrier in an amount in excess of the solubility of the adjuvant in the liquid carrier. Alternatively, the charge control adjuvant may be dispersed in a matrix having limited solubility in the liquid carrier or encapsulated within a matrix to form microcapsules having limited solubility in the liquid carrier. The charge control adjuvant in any of the above forms may be provided in a number of formats for release into the toner composition as needed.