Image forming apparatus capable of controlling a moisture content quantity of a paper

摘要

The image forming apparatus transfers a toner image onto a print paper via a transfer roller having an electrode configured to apply a bias electric potential upon the print paper. The image forming apparatus includes a humidity detection sensor to detect a humidity of the print paper, a retention electrode to preserve the toner image transferred to the print paper by applying a bias electric potential upon the print paper and a control device configured to control the bias electric potential of each of the electrode of the transfer roller and the retention electrode. The control device measures moisture content quantity of the print paper based on an interval from commencement of variation in the humidity to a maximum quantity of variation of the humidity and controls the bias electric potential of the electrode of the transfer roller and the retention electrode according to the moisture content quantity thus measured.