| 摘要 |
PURPOSE:To copy an original of size larger than original platen glass and an original of normal size by varying process conditions according to original size. CONSTITUTION:When the large-sized original is copied, the line speed of a photosensitive drum 10 is equalized to the line speed of a fixing device 20 and the feed speed of the original is also made equal to the line speed of the photosensitive drum 10. The line speed of the fixing device 20 is the same with the original of normal size, but the line speed of the photosensitive drum 10 and the feed speed of the original decrease. Then, the discharging current of an electrostatic charging electrode 11 is lowered as compared with the copying of the original of normal size to lower the voltage of a light source for exposure. Discharging currents of a transfer electrode 17 and a separation electrode 18 are made equal to each other, but the DC bias applied to the separation electrode 18 so as to lower the potential of the photosensitive drum 10 to zero is made lower than that of the normal-size original. Consequently, a both-sided original is copied. |
