| 摘要 |
<P>PROBLEM TO BE SOLVED: To adequately apply an AC voltage from one AC power source to a plurality of charging rollers in an image forming apparatus of the type in which a DC voltage and an AC voltage are applied to a plurality of charging rollers so that these voltages overlap. <P>SOLUTION: The image forming apparatus has three image forming units 8Y, 8M, and 8C for color. A DC voltage is applied to the charging roller 16 of each of them from a corresponding individual DC power source 28, and also an AC voltage is applied to the charging roller 16 from an AC power source so as to overlap the DC voltage. An ammeter 33 is arranged in each DC power source circuit 32. Based on the measurement value of the ammeter 33, a saturation inflow current value, which flows in the DC power source 28, is calculated. The output of the AC power source is set so as to maintain the highest saturation inflow current value. Since the minimum required AC voltage is applied from the AC power source, adverse effects such as discharge and member wear are prevented and hence an image of high quality can be obtained. <P>COPYRIGHT: (C)2012,JPO&INPIT |
