| 摘要 |
PURPOSE:To obtain an image forming device by which a high-quality image is obtained by easily selecting optimum developing bias voltage even when the characteristic of the electric resistance of developer is changed. CONSTITUTION:The latent image of a reference pattern 700 is repetitively formed five times in a rotating direction at positions having different axial direction on the respective photosensitive drum surfaces of four colors. The five latent images in the rotating direction are developed by making the magnitude of the AC component (Vp-p) of the developing bias voltage different, and the toner images of respective colors are transferred on one recording paper 800. An operator compares and evaluates the plural images of the reference pattern, selects the optimum value of Vp-p (the peak of the AC component), and sets it as the standard condition of Vp-p in the case of forming the image next time. The reference pattern 700 is constituted of the solid image having three kinds of density. Present Vp-p is included in Vp-p at the time of forming the toner image. Upper and lower limit values are set to Vp-p, and an image producing process condition may be changed for the color where Vp-p is changed. |
