Patent ID: 8374520

Claim:
An image forming apparatus comprising: an image carrying unit configured to carry an image developed by a developer; a charging unit configured to charge the image carrying unit; a transfer unit configured to transfer the image to a recording medium in accordance with application of a transfer voltage; an application unit configured to generate the transfer voltage and apply the transfer voltage to the transfer unit; a voltage detection unit configured to detect the transfer voltage; an inflow current detection unit configured to detect an inflow current flowing from the image carrying unit charged by the charging unit into the application unit; a transfer current detection unit configured to detect a transfer current flowing when the transfer voltage is applied to the transfer unit; a determination unit configured to determine an initiating voltage which induces the inflow current; a calculation unit configured to calculate load resistance of the application unit based on the transfer voltage detected by the voltage detection unit, the transfer current detected by the transfer current detection unit, and the initiating voltage determined by the determination unit; an adjustment unit configured to adjust the transfer current in accordance with the load resistance calculated by the calculation unit; and a reverse voltage application unit configured to apply a reverse voltage having a polarity opposite to the transfer voltage to the transfer unit, wherein, in a state where the recording medium is not fed between the image carrying unit and the transfer unit, when the inflow current is equal to or larger than a predetermined value, the determination unit controls the reverse voltage application unit so as to gradually increase the reverse voltage, and when the inflow current becomes smaller than the predetermined value as the reverse voltage increases, the determination unit determines the reverse voltage at that time as the initiating voltage.