| 摘要 |
<p>PURPOSE:To obtain a toner for a charge controlling agent-free two-component magnetic developer excellent in spending resistance and electrostatic charge stability, prolonging the service life of the toner and carrier, ensuring stable electrostatic charge-ability in spite of no migrating charge controlling agent in the toner particles and capable of increasing apparent development sensitivity without scattering the toner at the time of development. CONSTITUTION:A copolymerized resin having anionic polar groups or a resin compsn. is used as a fixing resin medium, magnetic powder and carbon black of <pH 7 having 90-200m<2>/g BET specific surface area and >=50ml/100g DBP oil absorption are incorporated into the resin medium by 0.1-5pts.wt. and 4-15pts. wt. per 100pts. wt. of the resin medium, respectively, and the resulting toner is regulated so that the absorption peaks of a liq. obtd. by extracting the toner with methanol in the wavelength ranges of 400-700nm and 280-350nm are made practically zero. Spacer particles having 0.05-1mum particle diameter are allowed to exist in a flowability improver added to the toner.</p> |
