Patent ID: 7105260

Claim:
A binder resin for a toner comprising a polyester resin, wherein the polyester resin comprises 0.1 to 40% by weight of tetrahydrofuran insoluble component (A-1) and 99.9 to 60% by weight of tetrahydrofuran soluble component (A-2); the tetrahydrofuran insoluble component (A-1) has a polyester structure unit comprising; a terephthalic acid-derived structure unit (I), a polyhydric alcohol-derived structure unit (II) comprising 39.9 to 75 mole % of a dihydric alcohol-derived structure unit (II-1-1) having 2 to 10 carbon atoms, 0.1 to 20 mole % of a trihydric alcohol-derived structure unit (II-1-2) having 3 to 10 carbon atoms and 15 to 60 mole % of a dihydric alcohol-derived structure unit containing bisphenol skeleton (II-2), each mole % being based on 100 mole % of the total moles of all the polyhydric alcohol-derived structure unit in component (A-1), and 0.1 to 30 mole % of di- or higher functional atomic group structure unit (III) of 1 to 20 carbon atoms having one or more kinds of elements selected from C, H, N, O and S, based on 100 mole % of the total moles of all the polyhydric alcohol-derived structure unit in component (A-1); and the tetrahydrofuran soluble component (A-2) has a polyester structure unit comprising; a terephthalic acid-derived structure unit (I), a polyhydric alcohol-derived structure unit (IV) comprising 40 to 85 mole % of a dihydric alcohol-derived structure unit (IV-1) having 2 to 10 carbon atoms and 15 to 60 mole % of a dihydric alcohol-derived structure unit containing bisphenol skeleton (IV-2), each mole % being based on 100 mole % of the total moles of all the polyhydric alcohol-derived structure unit in component (A-2), 2 to 20 mole % of tri- or higher functional atomic group structure unit (V) of 1 to 20 carbon atoms having one or more kinds of elements selected from C, H and O, based on 100 mole % of the total moles of all the polyhydric alcohol-derived structure unit in component (A-2), and 0 to 10 mole % of di- or higher functional atomic group structure unit (VI) having 1 to 20 carbon atoms based on 100 mole % of the total moles of all the polyhydric alcohol-derived structure unit in component (A-2).