| 摘要 |
PURPOSE: To provide a toner carrier excellent in processability, having a surface layer reduced in change in electric characteristics caused by humidity change and the lapse of time by controlling magnetic characteristics to a desired value by magnetic powder quantity irreducibly minimum and controlling the electric characteristics, specially volume resistivity, to the desired value. CONSTITUTION: By using a developing roller where a surface layer 22 is formed by coating a core bar 21 being an electrically conductive supporting body with resin obtained by adding magnetic powder and electrically conductivity imparting agent to binder resin, the electric characteristics required by the surface layer of the developing roller is obtained by the addition of the conductivity imparting agent to the binder resin, so that the added quantity of the magnetic powder to the binder resin is reduced to the minimum for obtaining the magnetic characteristics required by the surface layer of the developing roller. |
