Abstract: A gas current classifier has a material feed nozzle, a Coanda block, a classifying wedge and a classifying wedge block having the classifying wedge. The Coanda block and the classifying wedge define a classification zone, and the classifying wedge block is set up in the manner that its location is changeable so that the form of the classification zone can be changed.

Abstract: A gas current toner classifier has a material feed nozzle, a Coanda block, a classifying wedge and a classifying wedge block having the classifying wedge.The Coanda block and the classifying wedge define a classification zone, and the classifying wedge block is set up in the manner that its location is changeable so that the form of the classification zone can be changed. A method of producing toner using said classifier is also described.

Abstract: A gas stream classifier includes: a gas stream classifying means for classifying feed powder into at least a coarse powder fraction and a fine powder fraction by an inertia force acting on particles and a centrifugal force acting on a curved gas stream due to Coanda effect in a classifying chamber, and a feed supply pipe opening into the classifying chamber for supplying the feed powder into the classifying chamber. The efficiency of the classifier is improved by providing the feed supply pipe with a mixing zone for mixing an upper stream and a lower stream of the feed powder and an accompanying gas stream, respectively flowing through within the feed supply pipe. The classifier is particularly suitably used for producing a toner for developing electrostatic images having a sharp particle size distribution from toner particles having a weight-average particle size of at most 10 .mu.m, especially at most 8 .mu.m.