| 摘要 |
PURPOSE:To stabilize performances against uses for a long time and against changes of environmental conditions by using specified alumina particles as external additives of the color toner. CONSTITUTION:The alumina particles to be used as the external additives of the color toner have a saturated water content QL of >=1.5wt.% at 15 deg.C and a relative humidity of 10% and that QH of <=12wt.% at 32.5 deg.C and 85%, and QH/QL<=3, and a specific surface area SB measured by the BET method is 30 - 300m<2>/g. The alumina particles function as a sort of spacer, as a result, forms parts low in electric chargeability on the surfaces of the toner particles and weaken the attaching force of the toner particles to each other and alleviate direct contact between the toner particles and carrier surfaces, thus permitting high-quality images to be stably obtained for a long period. |
