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Toner emulsion aggregation processes

  • US 5,370,963 A
  • Filed: 06/25/1993
  • Issued: 12/06/1994
  • Est. Priority Date: 06/25/1993
  • Status: Expired due to Term
First Claim
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1. A process for the preparation of toner compositions with controlled particle size consisting essentially of:

  • (i) preparing a pigment dispersion in water, which dispersion is comprised of pigment, an ionic surfactant, and an optional charge control agent;

    (ii) shearing at high speeds the pigment dispersion with a polymeric latex comprised of resin, a counterionic surfactant with a charge polarity of opposite sign to that of said ionic surfactant and a nonionic surfactant thereby forming a uniform homogeneous blend dispersion comprised of resin, pigment, and optional charge agent;

    (iii) heating the above sheared homogeneous blend below about the glass transition temperature (Tg) of the resin while continuously stirring to form electrostatically bounded toner size aggregates with a narrow particle size distribution;

    (iv) heating the statically bound aggregated particles above about the Tg of the resin particles to provide coalesced toner comprised of resin, pigment, and optional charge control agent, and subsequently optionally accomplishing (v) and (vi);

    (v) separating said toner; and

    (vi) drying said toner.

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