Binding resin for toner, toner and electrophotographic apparatus

A method for preparing a toner comprising the steps of:

• preparing a toner composition containing the binder resin which has,
• a molecular weight maximum peak in a range of molecular weights from 2×103 to 3×104 in molecular weight distribution of GPC chromatogram, and
• a component having a molecular weight of not less than 3×104, as a component located in high molecular weight range, in an amount of not less than 5% based on the entire binder resin;
• and
• kneading the toner composition so that a high molecular weight component of the binder is converted into a low molecular weight component by thermal or mechanical energy exerted at the time of kneading.

A method for preparing a toner comprising the steps in which:

• two opposing rolls capable of heating or cooling that are rotated in different directions is employed, a temperature difference is provided between the roll temperature of one of the rolls (RL1) and the temperature of the other roll (RL2), and the roll (RL1) and the roll (RL2) are rotated at mutually different peripheral speeds;
• and
• a toner composition containing at least a binder resin and colorant is supplied from a material supply feeder to a gap between said two rolls so that said binder resin is melted with an internal additive agent being dispersed therein,
• wherein the material feeder is inserted from the roll (RL2) side so that said toner composition is allowed to drop on a surface of said roll (RL1) within in a range from 20° to 80° from a position at which said roll (RL1) and said roll (RL2) are most closely located, in a direction opposite to the rotation direction of said roll (RL1).