| 摘要 |
PURPOSE:To prevent color mixture and to obtain a copy of high quality by scattering part or the whole of a developer to a no-image area on a latent image carrier and removing said part or whole of the developer from the surface of its developing roller. CONSTITUTION:A bias voltage of hundreds - thousands volts which has the same polarity with toner put in each developing unit is applied to a developing roll 5a in a rotation stop state before an electrostatic latent image on the surface of the photosensitive body begins to be developed and developing rolls 4a and 6a which are also in the rotation stop state and positioned on the upstream and downstream sides of said developing roll 5a. Therefore, the no-image area on the surface of the photosensitive drum is developed forcibly by the respective developing rollers 4a, 5a, and 6a. Mixed color toner on the developing roll 5a which is selected by said forcible development is carried to the no-image area on the photosensitive body before the electrostatic latent image on the surface of the photosensitive body reaches the developing rolls, thus preventing an image area from being developed with the mixed color toner. |
