Crash cooling method to prepare toner
View Patent ↗The present disclosure relates generally to a method to make a chemically prepared toner that employs a crash cooling process. In particular, the crash cooling process involves the addition of a toner slurry having a temperature between 70° C. and 90° C. to an equivalent amount of cold water having a temperature between 5° C. and 20° C. Polyester and styrene acrylic toners as well as polyester core shell toners having a borax coupling agent between the toner core and toner shell made from this cooling process results in an improvement to the amount of toner waste, thereby achieving a higher toner usage efficiency for an electrophotographic printing system.
1. A method for producing a core shell toner, comprising:
combining and agglomerating a polymer emulsion with a colorant dispersion and a release agent dispersion to form toner cores;
adding a borax coupling agent to the toner cores once the toner cores reach a predetermined size;
combining and agglomerating a second polymer emulsion with the toner cores having the borax coupling agent to form toner shells around the toner cores;
fusing the aggregated toner cores and toner shells to form toner particles;
forming a toner slurry by suspending the toner particles in an aqueous medium wherein the toner slurry has a temperature between 70° C. and 90° C.;
adding the toner slurry to an equivalent amount of cold water wherein the cold water has a temperature between 5° C. and 20° C.;
filtering the toner particles out of the toner slurry;
washing the filtered toner particles; and
repeating the filtering and washing steps until toner particles have an average particle size of between about 3 μm and about 10 μm.
2. The method of claim 1 , wherein the ratio of the toner slurry to the cold water is at least 1:1.
3. The method of claim 1 , wherein the toner slurry has a temperature between 80° C. and 84° C.
4. The method of claim 1 , wherein the cold water has a temperature between 7° C. and 14° C.
5. The method of claim 1 , wherein the toner slurry is added to the cold water in an external reactor.
6. The method of claim 1 , wherein the first polymer emulsion and the second polymer emulsion each include an amorphous polyester resin.
7. A toner prepared by the process of claim 1 .
8. A method for producing a core shell toner, comprising:
combining a first polymer emulsion with a colorant dispersion and a release agent dispersion to form toner cores;
adjusting the pH of the combination of the first polymer emulsion, the colorant dispersion and the release agent dispersion to promote agglomeration of the toner cores;
once the toner cores reach a predetermined size, adding a borax coupling agent to the toner cores;
combining a second polymer emulsion with the toner cores having the borax coupling agent and forming toner shells around the toner cores;
once a desired toner particle size is reached, adjusting the pH of the mixture of aggregated toner cores and toner shells to prevent additional particle growth;
fusing the aggregated toner cores and toner shells to form toner particles;
forming a toner slurry by suspending the toner particles in an aqueous medium wherein the toner slurry has a temperature between 80° C. and 84° C.;
adding the toner slurry to an equivalent amount of cold water wherein the cold water has a temperature between 7° C. and 14° C.;
filtering the toner particles out of the toner slurry;
washing the filtered toner particles; and
repeating the filtering and washing steps until toner particles have an average particle size of between about 3 μm and about 10 μm.
9. The method of claim 8 , wherein the toner slurry is added to the cold water in an external reactor.
10. The method of claim 8 , wherein the first polymer emulsion and the second polymer emulsion each include an amorphous polyester resin.