Gas current classifier and process for producing toner

摘要

A gas current classifier which comprises a classifying chamber, a material feed nozzle for introducing a material powder into the classification zone of the classifying chamber, and a Coanda block for classifying the material powder thus introduced by the Coanda effect to separate the powder into at least a fraction of fine powder and a fraction of coarse powder, wherein the material feed nozzle has a material receiving opening for introducing the material powder into the material feed nozzle the material powder is introduced into the classification zone from an orifice of the material feed nozzle while its flow is accelerated by the gas stream within the material feed nozzle and the Coanda block is provided at a position higher than the orifice of the material feed nozzle.