| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain nonspherical granules having a narrow particle size distribution with sufficiently controlled particle diameters and exhibiting good static build-up characteristics by a specified processing in the step of associating fine polymer particles to give a nonspherical granule having a diameter suitable for a toner. SOLUTION: In preparing a nonspherical granule by associating fine polymer particles, the following means are used: an aqueous solution of an alkali metal salt is added in a critical aggregation concentration or higher to a dispersion of fine polymer particles; an organic solvent infinitely soluble in water is added to the polymer particle dispersion containing an alkali metal salt; and this mixture is heated to a temperature at least equal to the glass transition temperature of the polymer particles. The organic solvent infinitely soluble in water is selected from those which do not dissolve the polymer particles. It is desirable that the fine polymer particles contain monomer units having an ionic dissociating group (e.g. a carboxyl group, a sulfo group, a phosphate group or an amino group). The fine polymer particles can compound solid ingredients comprising, e.g. a dye, a pigment, a fixability improver and an antistatic agent.</p> |
