We developed a polyester color toner with a broad fusing latitude of from 150°C to over 220°C, using our proprietary ‘Chemical Milling Process’. In this study, we explored the relationship between the fusing latitude and the chemical milling property, on the one hand, and the chemical structure of toner resin, especially molecular weight, molecular weight distribution and the amount of long chain branching, on the other. The fusing latitude, in a hot roll fusing system (both soft and hard roll), expanded with the degree of branching while the chemical milling property was little affected by the branching. The hot offset temperature increased with the degree of branching whereas the cold offset temperature was not affected. An attempt to understand the results in terms of effects of the branching on resin physicochemical properties such as the acid value, the polymer chain dimension and thermo-rheological property is to be presented.