| 摘要 |
A voltage from a high voltage power source is applied between a toner support and an opposing electrode to generate an electric field between the two elements which permits the toner carried on the toner support to jump to the opposing electrode side. A control electrode is provided between the developer support and the opposing electrode to control the jumping of the toner. The control electrode is formed with annular electrodes around gates through which the toner passes through. Each annular electrode is supplied with a voltage for causing the toner to jump or for prohibiting the toner from jumping. In applying the voltage for causing the toner to jump to each annular electrode, the control power source starts to apply a voltage for prohibiting the toner from jumping, to annular electrode at a time when the jumping toner travel past the location of the control electrode. In this situation, the traveling toner continues to move toward the recording paper on the opposing electrode. Therefore, the time during which the voltage for causing the toner to jump is applied will not exceed the time required for the toner to reach the recording paper. As a result, it is possible to reduce the time span from a toner jump event to the next, and this feature improves the recording speed.
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