Abstract: A toner binder comprising a crosslinked polyester resin obtained by using 0.1 to 3 mol % of trimellitic acid and 0.1 to 5 mol % of an epi-bis type epoxy in combination as crosslinking components, said binder having a number average molecular weight (Mn) in the chromatogram determined by a gel permeation chromatography on the non-gel portion of the polyester resin, of 2,000 to 4,000, a ratio (Mw/Mn) of the weight average molecular weight to the number average molecular weight of 10 to 25 and a (percent gel) of the residue unsoluble in tetrahydrofuran solvent of 1 wt % or less. A toner composition for flash fixing comprising the above-described binder as an essential constituent component. The toner and the toner binder exhibit good fixability and void resistance upon flash fixing and produce little fixing odor.

Abstract: A process for producing a wherein an aminium salt infrared light absorber and a positive charge control agent are used in combination while preventing a mutual reaction therebetween. In this toner, the physical contact of the aminium salt compound with the positive charge control agent is avoided (e.g., by separately adding them to respective two separated phases of a binder resin), or alternatively use is made of such a combination of confounds as will not cause a mutual reaction (e.g., a common anion is used).

Abstract: A toner is disclosed wherein an aminium salt infrared light absorber and a positive charge control agent are used in combination while preventing a mutual reaction therebetween. In this toner, the physical contact of the aminium salt compound with the positive charge control agent is avoided (e.g., by separately adding them to respective two separated phases of a binder resin), or alternatively use is made of such a combination of compounds as will not cause a mutual reaction (e.g., a common anion is used).