| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent filming of the toner on the surface of a photoreceptor, to reduce tendency to cause film abrasion and to eliminate problems on character deficiency by attaching alumina particles, specified in a ratio of BET specific area to tapping density, to the surfaces of the toner particles containing a a binder resin a colorant. SOLUTION: The alumina particles having a ratio of BET specific area to tapping density of <4 are attached to the surfaces of the toner particles containing the binder resin and the colorant. These alumina particles are ultrafine particles obtained by hydrolyzing anhydrous aluminium chloride at high flame temperature or the like method and their surfaces are treated with a coupling processing agent. The above-mentioned ratio can be satisfied by selecting the forms of the alumina particles and, when the coupling processing agent is used, it can be attained by selecting the kinds of coupling processing agents and the amounts of the processing agents.</p> |
