| 摘要 |
A developing device has a brush-like toner carrying roller for carrying charged toner and a toner supply roller which is in contact with the toner carrying roller and charges the toner by friction, and applies a voltage having the same polarity as the charging polarity of the toner to the toner supply roller. With this arrangement, since the charged toner and the toner supply roller produce repulsion therebetween, it is possible to carry a sufficient amount of toner on the surface of the toner carrying roller. Therefore, even when the electric field strength is weak, it is possible to cause a sufficient amount of toner to fly from the surface of the toner carrying roller. Consequently, a quality image can be stably produced with an inexpensive small-size structure. Moreover, by moving the toner carrying roller to a position where it comes into contact with a grid electrode and cleaning the grid electrode with the rotating toner carrying roller, it is possible to prevent a lowering of the image quality due to adhesion of the toner to the grid electrode. <IMAGE> |
