Abstract: A toner using an organic solvent-insoluble resin and a method of preparing the same. The toner includes: a binder resin that comprises an organic solvent-insoluble resin and an acid group-containing resin, a coloring agent, and at least one additive, wherein the organic solvent-insoluble resin is a crosslinked polyester resin or a cyclic olefin co-polymer (COC) resin, and the ratio of the organic solvent-insoluble resin to the acid group-containing resin is in the range of 5:95 to 40:60 on a weight basis. The toner can be applied to an electrophotographic imaging apparatus.

Abstract: Provided are an electrophotographic toner and an electrophotographic image forming apparatus using the same. The electrophotographic toner includes: parent toner particles including a binder resin, a colorant, a releasing agent, and a charge control agent; and barium titanate external additives having an average primary particle diameter in the range of about 50 to about 150 nm, an average shape factor (SF1) in the range of about 100 to about 120, a shape factor in the range of about 0.96 to about 1, and an aspect ratio in the range of about 0.89 to about 1, and added to the surface of the parent toner particles.

Abstract: Provided are a toner using a resin having an active hydrogen-containing group, and a method of preparing the toner. The toner using a resin having an active hydrogen-containing group includes a binder resin (A), a cross-linked resin including a THF insoluble content of 99-100 weight %, a colorant, and at least one additive. The cross-linked resin is arranged in the form of a plurality of islands in each particle of the toner.

Abstract: A method of preparing a toner having a core-shell structure. The method includes: preparing a mixture by mixing a resin with acid groups, a coloring agent and at least one additive with an organic solvent, and neutralizing the acid groups of the resin with a base; forming a micro-suspension solution by adding the mixture to a dispersion medium; forming a toner core by removing the organic solvent from the micro-suspension; and forming a toner complex having a core-shell structure by seed-polymerizing at least one monomer on the surface of the toner core. Thus, the toner that can prevent hot offsets, improve storage stability at a high temperature and improve charge stability against environment changes can be prepared with reduced costs according to the method.

Abstract: The present invention relates to a process for preparing optically pure (S)-3-hydroxy-&ggr;-butyrolactone expressed by the following Formula 1 and more particularly, to a process that enables preparing optically pure (S)-3-hydroxy-&ggr;-butyrolactone economically in large quantities, by: