JPS6484259A - Production of toner for developing electrostatic image - Google Patents

Abstract

PURPOSE:To improve a capacity for producing the title toner of a second crushing means by removing coarse particles having larger particle size than a specified particle size with a first crushing means and a first classifying means, transporting fine particles having a particle size near the particle size of a toner to a second classifying means, and crushing it with a second crushing means. CONSTITUTION:A crushed product obtd. in a first crushing means is transported together with a feed materials (d) to a first classifying means 1, and classified therein to first coarse power (a) and first classified powder (b). The classified first coarse power (a) is introduced into a first crushing means 5, where it is crushed and fed again to the first classifying means 1. The first classified powder classified in the first classifying means 1 is classified further in the second classifying means 2. Second coarse power (c) is crushed in a second crushing means 6 and transported again to the second classifying means 2. In this case, the first classification is performed by introducing the feed material for crushing into a multiply divided classification zone divided into a least two by classifying fences, falling the powder therein, and the second classification is performed by introducing the first classified power (b) into a multiply divided classifying zone divided at least three sections by classifying fences, and falling the powder therein. By this constitution, a toner for development of electrostatic image having uniform and fine particle size distribution is obtd. efficiently.