Silica-Polymer Composite Particles for Toners: Synthesis, Characterization and Performance

Abstract

Evolution of toner technology together with a demand for faster printing puts new requirements on external additives used in toner formulations. Spacer particles, which are added to protect the toner surface from mechanical stress resulting from collisions with the particles of carrier or the doctor blade, have become a progressively more important part of the additives packages.Polymeric particles, colloidal silica, and low surface area fumed silica are usually used as spacers. However, each of these materials has significant drawbacks. For instance, triboelectric charging properties of polymeric particles are not always optimal, large colloidal silica often drops off from toner surface, and low surface area fumed silica typically has broader than desired aggregate size distribution.At the NIP28 conference we introduced the organic/inorganic composite spacer additives which combine benefits of polymeric and colloidal silica spacer additives [1]. We demonstrated that the new particles have lower drop off from the toner surface than colloidal silica additives.In this paper we demonstrate how the new material particle size and shape could be controlled and present results of a print test where a model toner was formulated with the silica-polymer composite spacer additives.