| 摘要 |
PURPOSE:To obtain an image of high contrast by making the timing when an electrically charged photoconductive toner is exposed to light to extinguish the electric charge different from the timing when electric charge having a polarity opposite to that for electric charge is applied to the toner which loses the electric charge. CONSTITUTION:A prescribed electric field is formed between a conductive electrode 12 and a conductive substrate 11 by a voltage applied from a power source 13. The toner which loses the electric charge by exposure on the conductive substrate 11 is charged with a negative electric charge from the substrate 11 to have the negative polarity. The toner having one polarity on the substrate 11 is electrostatically transferred to transfer paper by a prescribed transfer device. In case of transfer of the toner which has the negative polarity by exposure, plus corona discharge is performed from the rear face of the transfer paper, and only the toner having the negative polarity is electrostatically transferred onto the transfer paper, and there is not a fear that the toner having the positive polarity on the substrate 11 is transferred. The timing when the electric charge of the toner which is not exposed is attenuated is delayed, and this toner at the time of transfer keeps a high extent of electric charge, and the potential difference between this toner and the exposed toner is increased to obtain an image of high contrast. |
