| 摘要 |
PURPOSE:To realize a novel 2-component type developer carrier electrostatically chargeable in surficient velocity and prevented from deterioration of image density and fogging and the like by forming coats composed of an upper charge control layer and a lower charge control layer on a core material. CONSTITUTION:The 2 carrier-coating layers composed of the upper charge control layer and the lower charge control layer are formed on the core material. In this case, it is found that the chargeability characteristics contributed by the upper charge control layer exerts an effect in an comparatively early stage at the time of triboelectrification between the toner and the carrier, and the chargeability characteristics contributed by the lower charge control layer exerts an effect in a comparatively late stage. Consequently, chargeability in sufficient velocity can be attained and disadvantages, such as deterioration of image density and increase of fog, can be eliminated by using a carrier- coating material ranking near to the toner in the triboelectrification series for the upper or lower layer, and a carrier-coating material ranking considerably apart from the toner in said series for the lower or upper layer. |
