Patent ID: 6495302
Filing Date: 2002-12-17
Classification: G03G

Abstract:
A process for the preparation of toner comprising, in order,(i) generating an initial latex emulsion of resin, water, and an ionic surfactant, and a colorant dispersion of a colorant, water, and an ionic surfactant, or a nonionic surfactant, and wherein (ii) the latex emulsion is blended with the colorant dispersion; (iii) adding to the resulting blend containing the latex and colorant a coagulant of a polyaluminum chloride with an opposite charge to that of the ionic surfactant latex colorant; (iv) heating the resulting mixture below or equal to about the glass transition temperature (Tg) of the latex resin to form aggregates; (v) adding an organic water soluble or water insoluble chelating component to the aggregates of (iv) particles, followed by adding a base to change the resulting toner aggregate mixture from a pH which is initially from about 1.9 to about 3 to a pH of about 5 to about 9; (vi) heating the resulting aggregate suspension of (v) above about the Tg of the latex resin; (vii) optionally retaining the mixture (vi) at a temperature of from about 70Â° C. to about 95Â° C.; (viii) changing the pH of the mixture (vi) or (vii) by the addition of an acid to arrive at a pH of about 1.7 to about 4; and (ix) optionally isolating the toner.