| 摘要 |
PURPOSE:To efficiently form the precise particle distribution of this toner by leading the classified coarse particles of a first fractional zone into a grinding means by grinding it again, separating and removing the fine particles of a third fractional zone and obtaining the middle size particles in a second fractional zones as a toner. CONSTITUTION:The raw particles for grinding are fed to a first classifying means to remove a coarse particle fraction, and the classified coarse particle group is delivered to a grinding means constituted of a collision type pneumatic grinding membrane, and then returned again to the first classifying means. The fine particles removing the coarse particles group are delivered to a multifractionally classifying zone to be classified in 3 kinds particle size fractions, and the particle group of a larger particle size fraction is led into a grinding means. The particle groups of the specified particles sizes of the middle particle size fraction and the particle groups less than the specified particle size of the smaller particle size fraction are taken out from the multifractionally classifying zone by a proper takeing-out means. The particle group from the middle particle size fraction is in a suitable particle distribution and that can be used as the toner as it is. condition. Thus the superior prescribed particles size is obtained at a low cost. |
