| 摘要 |
PURPOSE:To obtain uniform printing density on an ordinary paper, not to mention, on an envelope and on a ragged paper by controlling the electric current value of a transfer charger so that it may become an optimum value in accordance with the output of a means for detecting the electrostatically charged quantity of the paper. CONSTITUTION:When the paper on a paper tray 14 is fed to a laser printer main body by a paper feeding roller 13, the paper is electrostatically charged by the charge wire 11W of a dummy transfer charger 11 at first. On the other hand, it is confirmed by a control circuit 6 that the paper reaches the position of the dummy transfer charger 11, and then, the electrostatically charged quantity (charged quantity) is decided by the control circuit 6 based on a signal which is obtained by converting the electrostatically charged quantity detected by an electrostatic charging pickup 9 to a digital value by an A/D converter 10. Then, an electric current switching signal S which becomes the electric current value of the transfer charger 5 optimum to the paper is outputted to a transfer power pack 4 based on the charged quantity so as to decide the electric current value by the control circuit. Thus, the uniform printing density can be always obtained irrespective of the kinds of paper. |
