Toner processes
View Patent ↗A toner process comprising mixing a colorant dispersion with a latex, a wax dispersion, and a coagulant, and wherein the latex contains a polymer with a static yield stress of from about 0.05 to about 3 dyne/cm 2 , a viscosity for the polymer latex of from about 5 to about 35 centipoises (cps), and wherein said toner product possesses a volume average particle size distribution index GSDv of equal to or less than about 1.27, a number average particle size distribution index GSDn of equal to or less than about 1.30, a low number average particle size index GSDn 50/16 of equal to about or less than about 1.32, and a ratio of the volume average particle size distribution index GSDv to a number average particle size distribution index GSDn of from about 0.93 to about 1.
1. A process for forming a toner, comprising:
mixing a pigment dispersion with a polymer latex resin, a wax dispersion, and a metal halide coagulant in water, wherein the polymer latex resin contains a polymer selected from the group consisting of poly(styrene-butyl acrylate) and poly(styrene-butyl acrylate-β-carboxyethyl acrylate);
forming aggregates by heating the mixture at an aggregation temperature below the glass transition temperature of the latex resin;
increasing the pH of the aggregates with a base; and
coalescing the aggregates by heating the mixture at a coalescence temperature above the glass transition temperature of the latex resin and lowering the pH to between 5 to 6.5 with an acid to form toner particles;
wherein the polymer latex has a static yield stress of about 0.5 dyne/cm 2 and a viscosity of about 17.26 centipoises (cps); and
wherein the toner possesses a volume average particle size distribution index GSDv of about 1.19, a number average particle size distribution index GSDn of about 1.22, a low number average particle size index GSDn 50/16 of about 1.25, and a ratio of the volume average particle size distribution index GSDv to a number average particle size distribution index GSDn of about 0.975.
2. A process for forming a toner, comprising:
mixing a pigment dispersion with a polymer latex resin, a wax dispersion, and a metal halide coagulant in water, wherein the polymer latex resin contains a polymer selected from the group consisting of poly(styrene-butyl acrylate) and poly(styrene-butyl acrylate-β-carboxyethyl acrylate);
forming aggregates by heating the mixture at an aggregation temperature below the glass transition temperature of the latex resin;
increasing the pH of the aggregates with a base; and
coalescing the aggregates by heating the mixture at a coalescence temperature above the glass transition temperature of the latex resin and lowering the pH to between 5 to 6.5 with an acid to form toner particles;
wherein the polymer latex has a static yield stress of 0.5 dyne/cm 2 and a viscosity of 17.26 centipoises, and the toner has a GSDv of 1.19, a GSDn of 1.22, a GSDn 50/16 of 1.25, and a GSDv/GSDn ratio of 0.975.