| 摘要 |
PURPOSE:To provide an electrophotographic copying device that the deterioration of the quality of an image caused by that the AC component of a developing bias is induced on an electrostatic charge bias. CONSTITUTION:A power source for electrostatic charge E4 is constituted of a DC power source E4a and an AC power source E4b. Then, the bias obtained by superimposing the AC component to a DC component is supplied to an electrostatic charge roller 4 from the power source E4. Besides, a power source for developing E5 supplying the developing bias is also similarly constituted of a DC power source E5a and an AC power source E5b. Then, the bias obtained by superimposing the AC component to the DC component is supplied to a sleeve 5a from the power source E5. At this time, the power sources E4a and the E5a are set so that the oscillation frequencies thereof become (fd)-2fc=560Hz. Thus, the spatial frequency of the density stripe of the image generated on a transfer material becomes high to such an extent that it is not recognized to be the deterioration of the quanlity of the image for the human eyes. |
