Abstract: A toner containing a binder resin, a colorant, a charge control agent, and a thiazolyl disulfide compound or a thiuram disulfide compound. A process for producing a toner comprising polymerization of a polymerizable monomer composition that contains a polymerizable monomer and a colorant in an aqueous medium in the presence of a compound selected from a group consisting of (1) a thiazol thio compound, (2) a thiuram compound and (3) a dithiocarbamate compound.

Abstract: A toner containing a binder resin, a colorant, a charge control agent, and a thiazolyl disulfide compound or a thiuram disulfide compound. A process for producing a toner comprising polymerization of a polymerizable monomer composition that contains a polymerizable monomer and a colorant in an aqueous medium in the presence of a compound selected from a group consisting of (1) a thiazol thio compound, (2) a thiuram compound and (3) a dithiocarbamate compound.

Abstract: A toner for development of electrostatic images, comprising at least a binder resin, a colorant and a charge control agent, wherein the charge control agent contains a positive charge control resin (A) composed of a polymer having a weight average molecular weight of 1,000 to 100,000 and a functional group which brings positively charging ability, and a negative charge control resin (B) composed of a polymer having a weight average molecular weight of 1,000 to 100,000 and a functional group which brings negatively charging ability. The toner is excellent in flowability, shelf stability and charge properties, and provides images excellent in image quality.

Abstract: A toner for development of electrostatic images, obtained by subjecting a polymerizable monomer composition containing at least a colorant, a polymerizable monomer and a charge control agent to suspension polymerization in an aqueous medium containing a dispersing agent, wherein (a) the dispersing agent is a cationic inorganic dispersing agent; and (b) the charge control agent is a quaternary ammonium salt group-containing copolymer comprising a vinyl aromatic hydrocarbon unit, a (meth)acrylate unit and a quaternary ammonium salt group-containing (meth)acrylate unit, having a weight average molecular weight of 25,000 to 40,000 in terms of polystyrene as measured by gel permeation chromatography using tetrahydrofuran and containing the quaternary ammonium salt group-containing (meth)acrylate unit in a proportion of 1 to 15 wt. %, and a production process thereof.

Abstract: An additive for improving the dispersibility of a particulate substance in an organic medium, a thermoplastic polymer, or a thermosetting resin, is at least one compound having a ##STR1## bond in the molecule, including, for example, compounds having an oxazolinium ion in the molecule. The preferred additive compounds are oligomeric or polymeric.