Developing agent and manufacturing method thereof

摘要

A developing agent comprises first and second resin fine particles containing a colorant and a release agent and different in weight average molecular weight, and a concentration of the release agent which is softened at a low temperature in the second resin fine particles having the high weight average molecular weight is higher than a concentration of the release agent in the first resin fine particles, whereby thermal properties dependent on the weight average molecular weight of the resin fine particles are made uniform and fixability of the developing agent is improved.