| 摘要 |
PURPOSE:To provide an image forming device capable of providing stable color balance and image density. CONSTITUTION:Electric charge quantity applied to a photoconductor drum 10, that is, surface potential SP, and developing bias voltage Vbd applied to developing devices 14-20 are changed in the respectively independent state. The fluctuation quantity of contrast potential Vc and background potential Vbg changed likewise by the respective grade change of the surface potential SP and bias voltage Vbd is specified according to the change of image density obtained through the comparison between the measured value Q2 of toner supplied to the photoconductor drum 10 and the prediction value Q1 toner adhesion quantity. At the time of specifying the prediction value Q1, image data formed of characters and image data formed of photographs are separated, and the photographic image data is selectively used so as to maintain color balance and image density correctly. |
