Production of toner

TLDR: In this article, the authors proposed a method to prevent the floating of magnetic powder from a toner surface by long-period agitation by forming the toner in such a way that the magnetic powder is tightly adhered onto the surface of the electrostatically charged toner sticking onto a photoensitive drum.

Abstract: PURPOSE:To prevent the floating of magnetic powder from a toner surface by long-period agitation by forming a toner in such a manner that the magnetic powder is tightly adhered onto the surface of the electrostatically charged toner sticking onto the surface of a photosensitive drum. CONSTITUTION:A resin, coloring matter, etc. are measured and mixed. A synthetic resin is melted or softened by a heating kneader, etc., and the coloring matter, etc., are uniformly dispersed into the resin. The kneaded mixture is cooled to permit the easy crushing thereof and the cooled mixture is crushed to 1-3mm size by a hammer mill or cutter mill, etc.; further, the crushed mixture is pulverized to 3-50mum by using a jet mill. The powder of large grain sizes is removed and similarly the powder of very small grain sizes is removed in order to make the powder grain size (toner grain size) uniform. The toner is then put into a softened state by using a heating kneader, etc., and the magnetic powder having the grain size smaller than the toner grain size is added to such toner and is uniformly mixed therewith. The mixed toner is cooled in order to tightly adhere the magnetic powder thereto. The resultant toner has the magnetic powder tightly stuck to the surface.