| 摘要 |
PURPOSE:To always output an excellent image by always impressing an optimum transfer bias on a recording material in an image forming device constituted so that the recording material is passed through a transfer part between an image carrier and a transfer means brought into contact with the image carrier and the transfer feasible image of the image carrier is transferred on the recording material by impressing a bias voltage on the transfer means. CONSTITUTION:This device is provided with switching means RL, 41 and 40 selecting a bias voltage value for the transfer means 13. When the image of specified size is designated to be outputted, a method for controlling the bias voltage impressed on the transfer means 13 is changed by an external input means. Besides, the device is provided with a means manually switching or automatically controlling and switching the transfer bias voltage value. Moreover, it is provided with a means detecting at least two among the number of sheets used by a developing device, environmental humidity and the hygroscopic degree of the recording material and manually switching or automatically controlling and switching the transfer bias voltage value based on the detected values. |
