A polyester resin toner binder which gives a toner with good anti-blocking property at high temperature and high humidity and good low-temperature fixing ability. The present invention is directed to a toner binder for developing electrostatic charge images, which binder comprises a condensation-polymerization polyester resin, the polyester resin being a product formed in the presence of a catalyst (a) represented by the following general formula (I): Ti(-X)m(-OR)n (I) wherein R is H or a hydrocarbon group having from 1 to 24 carbon atoms which may contain from 1 to 3 ether bonds and/or from 1 to 2 hydroxyl groups; X is a residue formed by removing H of one carboxyl group from an aromatic mono- or polycarboxylic acid, provided that in the case of a polycarboxylic acid, a carboxyl group other than said one carboxyl group may intra molecularly polycondense with an OR group in the same molecule to form a ring structure or may form a structure where it has polycondensed intermolecularly with an OR group in another molecule; m=1 to 3, n=1 to 3, and the sum of m and n is 4.
Toner and Toner Binder