Patent ID: 9075329
Filing Date: 2015-07-07
Classification: G03G

Abstract:
1. A method of making toner particles comprising: a core comprising a styrene-butylacrylate latex resin, the core having a glass transition temperature Tg of from about 51° C. to about 59° C.; and a shell comprising a styrene-butylacrylate latex resin surrounding the core, the shell having a glass transition temperature Tg of from about 40° C. to about 70° C.; wherein: the volume average particle diameter of the core is from about 4.5 to about 5.5 μm; a ratio of an average particle diameter of the toner particles to an average particle diameter of the core is from about 1.1 to about 1.2; the toner particles have: a volume average particle diameter of from about 5.5 to about 5.9 μm; a weight average molecular weight (Mw) in a range of from about 20,000 pse to about 60,000 pse; a number average molecular weight (Mn) in a range of from about 8,000 pse to about 25,000 pse; a ratio of Mw to Mn of from about 1.2 to about 5.0; a particle size distribution with a lower number ratio geometric standard deviation (GSDn) of from about 1.05 to about 1.12, and an upper geometric standard deviation by volume (GSDv) of from about 1.05 to about 1.12; a circularity of from about 0.965 to about 0.999; a shape factor of from about 120 to about 150; and a surface area of from about 0.7 m the toner composition has: a crease minimum fix temperature (MFT) of from about 155° C. to about 185° C.; an offset temperature of from about 205° C. to about 215° C.; a compressibility of from about 9% to about 14% at 9.5 to 10.5 kPa; a density of from about 1.3 to about 1.8; a gloss, measured at the minimum fixing temperature (MFT), of from about 5 to about 20 gloss units; and a parent toner charge per mass ratio (Q/M) of from about −30 μC/g to about −65 μC/g; the method comprisings: forming a pre-shell aggregate mixture by adding to a reactor pre-shell aggregate ingredients, the pre-shell aggregate ingredients comprising: a latex resin; optionally a wax; optionally a colorant; optionally a surfactant; optionally a coagulant; optionally a chelating agent; and optionally one or more additional additives, the reactor comprising a mixing impeller and a heating jacket; performing pre-shell aggregation while homogenizing the pre-shell aggregate mixture with the impeller at an initial tip speed to form pre-shell aggregates; decreasing the tip speed to a second tip speed when the pre-shell aggregates reach a target intermediate average particle diameter; and then decreasing the tip speed at one or more intervals between when the pre-shell aggregates reach the target intermediate average particle diameter and when the pre-shell aggregates reach a target final average particle diameter so that the tip speed meets the following formula: stopping pre-shell aggregation when the pre-shell aggregates reach the target final average particle diameter; adding a shell latex to the pre-shell aggregates; and forming shells around the pre-shell aggregates to obtain post-shell aggregates, wherein a ratio of an average particle diameter of the post-shell aggregates to an average particle diameter of the pre-shell aggregates is from about 1.1 to about 1.