| 摘要 |
A process for the preparation of a toner composition includes (i) forming a resin latex dispersion of a resin in an aqueous ionic surfactant solution from a latex utilizing an ionic surfactant and optionally a nonionic surfactant; (ii) preparing a pigment dispersion in water of a pigment dispersed in water and a nonionic dispersant, and optionally an ionic surfactant of the same polarity as that employed in preparing the resin latex dispersion of step (i); (iii) blending at least a portion of the resin latex dispersion with the pigment dispersion, and optionally a wax dispersion, to form a resin-pigment blend; (iv) adding a portion of a counterionic coagulant in an aqueous solution to the resin-pigment blend, while continuously subjecting the mixture to high shear, to induce a homogeneous gel of the resin-pigment blend, wherein the amount of the counterionic coagulant added is 25 to 90% by weight of a total amount of counterionic coagulant to be added during the process; (v) heating the sheared gel at temperatures below a glass transition temperature (Tg) of the resin while continuously stirring to form aggregate particles; (vi) following a period of time to permit stabilization of aggregate particle size, adding a remaining portion of the total amount of counterionic coagulant to be added during the process in one or more sequenced stages; (vii) adding any remaining portion of the resin latex dispersion; (viii) changing the pH with a base in order to stabilize the aggregates; and (ix) heating the aggregate particles at temperatures above the Tg of the resin followed by reduction of the pH with an acid to form coalesced particles of a toner composition.
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