| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an electrophptographic developer composition which can easily be negatively electrified by a cascade method or a brush method even if an electric charge conditioner is not used and is excellent in fixing performance and blocking performance at a low temperature by containing a coloring agent and a binding resin containing a polyole resin on which a phenolic hydroxyl group quantity, a softening point and a glass transition temperature are specified as a main component. SOLUTION: A coloring agent and a binding resin containing a polyole resin having a phenolic hydroxyl group as a main component are contained in a molecule. The polyole resin being a main component of the binding resin contains a phnolic hydroxyl group by 600 to 2000(g/equivalent) in a molecule as a phenolic hydroxyl group equivalent, preferably, 700 to 1500(g/equivalent) from the viewpoint that a large negatively electrified quantity can be stably obtained. In this polyole resin, a softening point is 85 to 130 deg.C. In this polyole resin, a glass transition temperature Tg is 50 to 90 deg.C, and is preferably, 55 to 80 deg.C from the viewpoint of blocking resistance when it is left as it is under high humidity.</p> |
