Patent ID: 8450039

Claim:
A binder resin for color toners, wherein the binder resin comprises at least a carboxyl group-containing vinyl resin (C), a glycidyl group-containing vinyl resin (E) and a reaction product thereof, the storage modulus G′ at 160 degrees centigrade is not less than 20 Pa and less than 800 Pa measured at a frequency of 6.28 rad/sec, the tetrahydrofuran (THF) soluble portion in the binder resin has a main peak in the molecular weight region of not less than 20,000 and less than 40,000 in the molecular weight distribution measured by gel permeation chromatography (GPC), the binder resin contains at least one of releasing agents having a melting point of not lower than 60 degrees centigrade and not higher than 120 degrees centigrade in an amount of not less than 3.5 mass % and not more than 12 mass % based on 100 mass % of the total amount of said carboxyl group-containing vinyl resin (C), said glycidyl group-containing vinyl resin (E) and the reaction product thereof, said carboxyl group-containing vinyl resin (C) contains a high molecular weight vinyl resin (H) in which the THF soluble portion has a peak in the molecular weight region of not less than 150,000 and less than 350,000 in the GPC chromatogram and a low molecular weight vinyl resin (L) in which the THF soluble portion has a peak in the molecular weight region of not less than 20,000 and less than 40,000 in the GPC chromatogram, the mass ratio (H/L) of the high molecular weight vinyl resin (H) to the low molecular weight vinyl resin (L) in said carboxyl group-containing vinyl resin (C) is from 10/90 to 30/70, and the integrated value of the content of the tetrahydrofuran (THF) soluble portion in said binder resin in the molecular weight region of not more than 2,000 is not more than 7.0 mass % based on the total THF soluble portion.