AIR CURRENT CLASSIFYING DEVICE FOR MANUFACTURE OF TONER

PROBLEM TO BE SOLVED: To make it possible to set a correct classification point and thereby enable high accuracy classification by using at least, part of a raw material feed pipe, a classifying edge and an air intake edge formed of a resin molding composed mainly of polybenzoimidazole, in a classifying device for classifying a pulverized raw material by the centrifugal force of a curved air current. SOLUTION: An air current classifying device for classifying powder into a particle by an air current is equipped with knife edge-type classifying edges 17, 18 on a lateral wall 23 and a lower wall 25 respectively. In addition, a coanda block 26 is installed at the lower part of a raw material feed pipe 16 with an open part in a classifying chamber 32, and the knife edge-type air intake edge 19 is provided toward the lower part of a classifying chamber 32 in the upper block 27 of the classifying chamber 32. In this case, this inner wall face of the raw material feed pipe 16, the classifying edges 17, 18 and further, the outer wall face of the air intake edge 19 are formed in resin composed mainly of plastic polybenzoimidazole. Thus the lubricity of a streaming particle is improved and the wear resistance of these parts in enhanced.