Production process of toner for electrostatic image development

摘要

The toner for electrostatic image development has excellent charge properties, by which excellent toner particle size-controlling ability is achieved, and moreover the sharpening of a particle size distribution is achieved. The toner is composed of toner particles containing a binder resin. The process has an aggregating step of adding an aggregating agent containing a transition element into an aqueous medium of dispersed fine binder resin particles to aggregate the fine binder resin particles, and an aggregation-stopping step of adding an aggregation stopper composed on a sulfur atom-containing compound exhibiting a reducing action on the aggregating agent. The aggregating agent is a salt of a bivalent or higher metal selected from Sr, Ti, V, Cr, Mn, Fe, Co, Ni and Cu.

主权项

1. A production process of a toner for electrostatic image development, which comprises toner particles containing a binder resin, the process comprising:
an aggregating step of adding an aggregating agent composed of a compound containing a transition element into an aqueous medium in which fine binder resin particles formed of the binder resin have been dispersed, thereby aggregating the fine binder resin particles; and an aggregation-stopping step of adding an aggregation stopper composed of sulfur atom-containing compound exhibiting a reducing action on the aggregating agent into the aqueous medium in which the fine binder resin particles have been aggregated, wherein the aggregation stopper is composed of a sulfur atom-containing compound selected from sodium thiosulfate, sodium sulfite, sodium hydrogensulfite, sodium sulfide, hydrogen sulfide, sulfurous acid, sulfur dioxide, sodium hyposulfite, dithionous acid, sodium dithionite, thiourea dioxide, sodium α-hydroxymethanesulfinate and zinc α-hydroxymethanesulfinate.