Patent ID: 8155545
Filing Date: 2012-04-10
Classification: G03G

Abstract:
1. An image forming apparatus comprising: a charger including a charging wire and a grid; a voltage output circuit including a transformer having an auxiliary winding, the voltage output circuit being configured to generate a charge voltage using the transformer and apply the charge voltage to the charger; a grid-current detecting circuit configured to detect a grid current that flows between the charging wire and the grid in accordance with the applying of the charge voltage; a charge-voltage detecting circuit configured to obtain the charge voltage from a feedback voltage that is generated by the auxiliary winding; a calculating device configured to, in a testing mode to replace a discharge path between the charging wire and the grid with a testing resistor having a predetermined resistance, calculate the charge voltage using the resistance of the testing resistor and a detection value by the grid-current detecting circuit; and a controller configured to, in an image forming mode to form an image, detect the charge voltage from the feedback voltage using a relation between a value of the feedback voltage which is detected by the charge-voltage detecting circuit in the testing mode and the charge voltage calculated by the calculating device.