| 摘要 |
PURPOSE:To obtain a good image, by a method wherein an image carrier is charged for a predetermined time on the basis of the polarity corresponding to an image forming mode after change-over, before uniform charging due to image formation when said mode is positively or reversely changed over. CONSTITUTION:For example, when a reversal mode is changed over to a positive mode, a high voltage change-over circuit is changed over to a positive side,and a main motor 16, a charger 2, an erasure lamp 7 and the developing bias & sub-erasure lamp 8 of a developer 4 are turned ON to perform charging by one turn of a photosensitive drum 1 and the charger 2 is subsequently turned OFF. Next, when the charge finish region on the photosensitive drum 1 is opposed to the sub-erasure lamp 8, that is, charge elimination is finished, the lamps 7, 8, the developing bias and the motor 16 are turned OFF. As a result, the negative charge not sufficiently eliminated from the photosensitive drum 1 in the previous reversal mode is eliminated. At the time of the change over to the reversal mode, positive polarity charge is eliminated in the same way. By this method, a good image can be obtained. |
