| 摘要 |
PURPOSE:To charge toner powder electrostatically and sufficiently by friction and to form a layer of the toner powder to uniform layer thickness by composing a toner powder thin layer forming means of an endless belt which circulates around conductive elastic rollers and a toner layer thickness control means and forming a nonconductive resin surface layer on the endless belt. CONSTITUTION:The toner powder thin layer forming means consists of the endless belt 33 which circulates around the conductive elastic rollers 31 and 32 and the toner layer thickness controller 36. The endless belt 33 consists of the surface 33a made of a nonmagnetic resin material which contacts and charges supplied toner electrostatically by friction and a base layer 33b made of a metallic sheet. Toner powder 16 which is supplied onto the endless belt 33 from a housing 30 is charged electrostatically by coming into friction contact with the surface layer 33a. This toner powder forms a toner layer by sticking the surface of the belt 33 with a bias potential applied to the endless belt 33 through a conductive elastic roller 31 and a mirror image force generated on the belt and the layer is adjusted to uniform thickness. Consequently, the toner powder is charged on a developing means electrostatically and sufficiently by friction to obtain the uniform layer thickness. |
