Synthesis and characterization of styrenic‐based polymerized toner and its composite for electrophotographic printing

Abstract Suspension polymerization in an aqueous medium was applied to the syntheses of styrenic‐based polymerized toner particles. Poly(vinyl alcohol) and benzoyl peroxide were used as a dispersant and an initiator, respectively. The resulting polymerized toners were found to be smooth on their spherical surfaces, and the particle sizes were 4–10 μm with a coefficient of variation of 20–30%. In most cases, a correlation between small particle sizes with high weight‐average molecular weights was observed. The glass‐transition temperature ( T g ) of the polymerized toner could be controlled by the molar ratio of the comonomer between styrene and n ‐butyl acrylate (nBA). T g decreased when the content of nBA in copolymer increased, due to its rubbery state along with the increasing carbon black feed level, because the surface functional groups of the carbon black pigment inhibited the rate of polymerization and decreased the molecular weight of the resulting polymerized toners. The T g 's of the resulting polymerized toners were 66–70°C. Triboelectricity [the charge‐to‐mass ratio ( q / m )] of the resulting polymerized toners was 7–20 μCg −1 in the presence of borobis(1,1‐diphenyl‐1‐oxo‐acetyl)potassium salt. An analysis of print quality showed high background fog, low maximum density, and a small amount of image raggedness. The print result correlated with the q / m values. This article elucidates the polymerization technique, charging properties, and image qualities. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 238–248, 2003