Abstract: A toner composition for use in electrophotographic processes containing a resin binder which about 10 to 40% of THF-insoluble gel portion and about 60 to 90% of THF-soluble portion. The THF-soluble portion has a trimodal molecular weight distribution having three main peaks as shown in chromatograms from gel permeation chromatography, the first main peak has a molecular weight between 3,000 and 30,000, the second main peak has a molecular weight between 30,000 and 200,000, and the third main peak has a molecular weight between 200,000 and 2,750,000. The ratio among the first, second, and third main peaks is about 0.4-1.0/1/0.4-1.5, measured based on their respective peak heights. The resin binder further contains about 0.5 to 1.5% polysiloxane uniformly dispersed therein. The polysiloxane is added to the resin binder along with polymerization monomers during the polymerization reaction to produce the resin binder.

Abstract: A non-magnetic one-component toner developer for use in electrophotographic processes having a particle size distribution represented by the following expressions: d.sub.1 /d.sub.50 =0.32.about.0.55; d.sub.50 /d.sub.90 =0.50.about.0.70; and d.sub.50 =5-15.mu., wherein d.sub.1, d.sub.50, and d.sub.90 represent diameters of toner particles when the percentiles by volume or by weight of toner developer of that diameter are 1%, 50%, and 90%, respectively. The non-magnetic one-component toner developer disclosed in the present invention has a triboelectricity greater than 1.5 .mu.C/g, a bulk specific gravity than 0.36, and a compression ratio less than 0.24, and exhibits excellent triboelectrification characteristics and flowability, as well as provides uniformly clear images without foggy background.

Abstract: An electrophotographic toner composition for development of images, comprising:(a) an amount of 45 to 95% by weight of resin of which the dynamic viscosity after compounded and being fixed onto rollers, having been tested at a frequency rate of 6.28 RAD/sec, a strain of 10% being less than 20000 poise and dissipation factor being smaller or equal to 1.3, and(b) a releasing agent being less than 3% by weight.