DEVELOPMENT DEVICE AND IMAGE FORMING DEVICE

PROBLEM TO BE SOLVED: To gain a development device which prevents the inside of the device body from dirty with a developer without uselessly spending the developer, and also gain an image forming device. SOLUTION: The circuit of a power source device 98 is closed, and a bias voltage is applied between a layer thickness-controlling roll 87 and a development roll 86 to generate a potential difference. A negatively chargeable developer is used, and the potential of the layer thickness-controlling roll 87 is higher than that of the development roll 86. Then, an electric field is generated, and a developer T is drawn toward the layer thickness-controlling roll 87 side. Consequently, the developer T hardly comes out from the housing 80 of a development device 44, and the amount of the developer T on the development roller 86 decreases (processing for decreasing the amount of the developer). COPYRIGHT: (C)2010,JPO&INPIT