PRODUCTION OF TONER AND PRODUCTION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a process for production of toners by which the toners having a sharp grain size distribution is obtainable with high grinding efficiency and classification yield and continuous and stable production is possible. SOLUTION: A collision type air current pulverizing means is constituted to classify classified powder for forming toner particles by introducing the coarsely ground material to a first classifying stage to classify the material to first coarse powder and second fine powder and introducing the first classified fine powder into a second classifying stage. The means has an acceleration pipe for accelerating the transportation of the material to be ground by a high-pressure gas and a grinding chamber for pulverizing the material to be ground. A collision member having a collision surface disposed to face the opening surface at the outlet of the acceleration pipe is included in the grinding chamber. The collision surface has a projecting projection central part and the outer peripheral collision surface has a conical shape. The coarse powder classified by the first classifying stage and second classifying stage described above is introduced into the means described above where the pulverized coarse powder is introduced direct into a third classifying means for classifying the powder by utilizing intersecting air currents, a Coanda effect, by which the powder is classified to the second coarse powder and the second fine powder. The classified second coarse powder is introduced into the first classifying stage.