| 摘要 |
PURPOSE:To obtain powder not contg. fine particles at all and regulated to the same particle size by fusing fine particles into the surfaces of coarse particles by compression and intense friction in the gap between the surface of the inner wall of casing and a barrier member. CONSTITUTION:In a friction pulverizer for treating a kneaded compsn. passed through a pulverizing stage, a violent swirl is generated in casing 3 by rotating the casing 3 at a high speed and toner powder charged into the center of the casing 3 is pressed against the surface of the inner wall of the casing 3 by centrifugal force and whirled together with the inner wall. By this violent whirling motion, the toner powder is compressed by a barrier member 5 and the surface of the inner wall of the casing 3 and the compressed powder is further compressed in the gap between the peripheral end surface of the member 5 and the surface of the inner wall of the casing 3. At the same time, intense friction is caused, the surface of the toner powder is softened and the flowability is increased. Fine particles are fused into the surfaces of coarse particles and spherical particles hardly contg. fine particles which are contained before treatment and regulated to much the same particle size are obtd. Unlike heat treatment, this treatment prevents the coarse particles from melt-bonding to each other. |
