| 摘要 |
PURPOSE:To provide a good reversal development method by using a toner obtained by adding an electrically conductive particles to the surface of particles composed essentially of a resin and magnetic powder. CONSTITUTION:An electrostatic charge image on zinc oxide paper 7 is developed with a magnetic brush developing device having a rotatable permanent magnet 2 in the inside of a nonmagnetic electrically conductive cylinder 1. To execute reversal development in this case, bias voltage equal in polarity as an electrostatic charge image on the cylinder 1 is applied, and a one-component type magnetic toner is used having a volume resistivity of 10<9>-10<11>ohm.cm, and as conductive particles, carbon black of pH 6-8 added to the surface of the toner particles. As a result, the reversal development method thus invented permits stable development even in the widely set range of bias voltage and under extensive environmental conditions. |
