Sequenced addition of coagulant in toner aggregation process
US6120967A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 19, 2000 |
| Grant date | Sep 19, 2000 |
| Priority date | — |
| Expiry date | Jan 19, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G9/0825
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
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…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.