Abstract: In an image forming apparatus of the present invention, image signal electrodes are provided on a flexible printed circuit base in opposing relation to a developer carrying member such that they are disposed around the openings of developer passage holes, different voltages are applied thereto during dot formation and during non-dot formation, a throttle electrode is provided on the flexible printed circuit base in opposing relation to a counter electrode, a voltage always lower than the voltage applied to the image signal electrodes is applied to the throttle electrode when a developer of negative polarity is applied, and a voltage always higher than the voltage applied to the image signal electrodes is applied to the throttle electrode when a developer of positive polarity is applied.

Abstract: An image forming apparatus and an image forming method are characterized in that charged particle jumping can be controlled by applying signals having a small potential difference, and that low-voltage type switching devices can be used as switching devices for the power source. Control electrodes 16 are provided to move charged particles detached from a development roller 2 and to control the movement amount of the charged particles by generating a transfer electric field directly or indirectly between the development roller 2 and a rear electrode 8. A bias electrostatic field is generated between the development roller 2 and the control electrodes 16 by applying a voltage under a jumping start voltage, which is a voltage having the polarity opposite to the polarity of the charged particles and is lower than the jumping start voltage for detaching the charged particles from the development roller 2.