Patent ID: 7809293

Claim:
A method of checking continuity between a voltage generating circuit and an electrical load in an image forming apparatus comprising first and second electrodes, first and second voltage generating circuits, and first and second electrical loads, wherein the first voltage generating circuit and the first electrical load are electrically connected to the first electrode, and the second voltage generating circuit and the second electrical load are electrically connected to the second electrode, comprising: disconnecting the first electrical load from the first electrode; disconnecting the second electrical load from the second electrode; connecting a resistor having an impedance that is lower than the first and second electrical loads between the first electrode and the second electrode; generating a first voltage by the first voltage generating circuit for the first electrical load; generating a second voltage by the second voltage generating circuit for the second electrical load; detecting a voltage generated by the first voltage generating circuit; executing feedback control to bring the first voltage to a predetermined target value based on the detected voltage; and checking the continuity between the first voltage generating circuit and the first electrode and between the second voltage generating circuit and the second electrode based on a difference between the first voltage and the second voltage.