Patent ID: 8606123

Claim:
An image forming device comprising: an interface for mounting a replaceable unit; a blowing circuit for supplying a current for blowing a fuse when a unit containing the fuse is mounted; a detection circuit forming a circuit including the fuse contained in the mounted unit, for detecting a potential varying depending on whether or not the fuse has been blown; and a controller, wherein when a unit containing a fuse is mounted, in response to detection of a potential indicating that the fuse has not been blown by said detection circuit, said controller causes said blowing circuit to supply a current for blowing the fuse to the mounted unit containing the fuse, and checks operation of said blowing circuit based on potentials detected by said detection circuit before current supply and after current supply, respectively, and when a unit containing a non-blown component instead of a fuse is mounted, said controller causes said blowing circuit to supply a current to the mounted unit containing the non-blown component, and checks operation of said blowing circuit based on potentials detected by said detection circuit before current supply and during current supply, respectively, or potentials detected by said detection circuit during current supply and after current supply, respectively, wherein if the detected potentials differ in value, the controller determines normal operation of said blowing circuit.