| 摘要 |
<p>PURPOSE: To obtain such a toner that an enough charge amt. of the toner can be maintained for development without compounding a negative charge controlling agent, movement of a charge controlling agent to the carrier surface and electrification defect due to spent of the toner are avoided, and electrification performance of the toner can be stabilized for a long time, lives of the toner and the carrier are prolonged, a release agent can be uniformly dispersed, and thereby, image quality can be maintained for a long time. CONSTITUTION: This toner for a negative charge two-component magnetic developer consists of carbon black and a release agent dispersed in a resin medium for fixing. The resin medium for fixing consists of a copolymer having anionic polar groups and alkyl groups of >12 carbon number in the side chains or mixture of a polymer having anionic polar groups in the side chains and a polymer having alkyl groups of >12 carbon number in the side chains. The carbon black used satisfies that pH<7 and (7-pH)/specific surface area (m<2> /g) ranging from 0.010 to 0.050.</p> |
