| 摘要 |
PROBLEM TO BE SOLVED: To stably obtain an excellent image of delicate half tone provided with an appropriate image density, in performing the developing by making an AC electric field act to a developing area where a developer carrier and an image carrier facing each other. SOLUTION: In this device, by letting a surface of the developer carrier 11 holding the developer 2 while transporting to the developing area opposite to the image carrier 1, and alternately exerting a term T when AC electric field is actuated and the suspension term (t) when the AC electric field is not actuated, the development is performed. In this case, the direction of the electric field of first and second AC electric field in the exerting term of 1 when actuating the AC electric field is severally made in the same direction, and direction of the first electric field of the AC electric field in the next term after the suspension term passing is made in the reverse direction with respect to the direction of the last actuating time, or providing the suspension terms for ever time when the direction of the electric field of the AC electric field is changed, so that the next condition is satisfied, 0.20<=T/(T+t)<=0.90. |
