Toner processes

A process for the preparation of a magnetic toner comprising heating an acicular magnetite dispersion, a carbon black dispersion, a latex emulsion, and a wax dispersion, and wherein

• (i) said acicular magnetite dispersion contains water and an anionic surfactant, or a nonionic surfactant, and said dispersion of carbon black contains water and an anionic surfactant, or a nonionic surfactant;
• and wherein said carbon black dispersion possesses a pH of about 6.3 to about 6.8, and wherein said latex is an emulsion comprised of an anionic surfactant, water and resin, and which emulsion is at a pH of about 1.5 to about 2.5;
• (ii) wherein said colorant dispersion is blended with said latex emulsion, and thereafter adding a wax dispersion comprised of submicron wax particles of from about 0.1 to about 0.5 micron in diameter by volume, and which wax is dispersed in an anionic surfactant;
• (iii) wherein the resulting blend possesses a pH of about 2.2 to about 2.8 thereby inducing a positive charge on the magnetite particles to thereby initiate flocculation or aggregation of said resin latex, said colorant, and said wax;
• (iv) heating the resulting mixture below about the glass transition temperature (Tg) of the latex resin to form toner sized aggregates;
• (v) adding to the formed toner aggregates a second latex comprised of resin suspended in an aqueous phase containing an ionic surfactant and water, and stirring for a period of time to permit stabilization of aggregate particle size;
• (vi) adding to the resulting mixture a base to thereby change the pH, which is initially from about 2 to about 2.8, to arrive at a pH of from about 6.9 to about 7.3 for the resulting toner aggregate mixture;
• (vii) heating the resulting aggregate suspension of (vi) above about the Tg of the latex resin of (i), while maintaining the pH at a value of about 6.9 to about 7.3;
• (viii) retaining the mixture temperature at from about 85° C. to about 95° C. for an optional period of about 10 to about 60 minutes, followed by a pH reduction with an acid to arrive at a pH of about 5.3 to about 5.8;
• (ix) retaining the mixture temperature at from about 85° C. to about 95° C. for a period of about 7 to about 14 hours to assist in permitting the fusion or coalescence of the toner aggregates and to obtain smooth particles;
• (x) washing the resulting toner slurry;
• and
• (xi) isolating the toner.