| 摘要 |
PROBLEM TO BE SOLVED: To securely prevent both base fog and retransfer and to obtain a satisfactory image by providing an oscillating-voltage application means which applies an oscillating voltage to an electrifying brush, and a voltage waveform adjustment means which adjusts the waveform of the oscillating voltage. SOLUTION: The electrifying brush 24 is in contact with the surface of a photoreceptor 12, and rotates in a normal direction in relation to the direction of the movement of the photoreceptor 12 by means of a motor. To the electrifying brush 24, a power source circuit 26 composing the oscillating-voltage application means is connected. By an output voltage applied from the power source circuit 26 the surface of the photoreceptor 12 is electrified. The power source circuit 26 outputs the output voltage which is proportional to a drive voltage inputted from the voltage waveform adjustment means 46. By switching, according to a paper size, the amplitude of the voltage which is applied to the electrifying brush 24 and then applying the voltage, retransfer does not occur even in a letter size and in a postcard size, and also a satisfactory image flee of base fog can be obtained. |
