Image forming device with mounted replaceable unit, method of checking operation in that image forming device, and storage medium storing operation checking program directed to that image forming device

1. 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.

2. The image forming device according to claim 1 , wherein

said replaceable unit includes an identification component indicating which one of said fuse and said non-blown component is contained, and

said image forming device further comprises a type-specifying circuit for specifying a type of a mounted unit by electrical connection to said identification component.

3. The image forming device according to claim 1 , wherein

said controller is configured to determine that said blowing circuit is operating normally if a potential detected by said detection circuit while said blowing circuit supplies a current to said unit containing the non-blown component instead of a fuse is different from a potential detected by said detection circuit while said blowing circuit does not supply a current to the unit.

4. The image forming device according to claim 1 , wherein

said controller is configured to determine that said blowing circuit is operating normally if a potential detected by said detection circuit after said blowing circuit supplies a current to said unit containing the non-blown component instead of a fuse over a certain period is not different from a potential detected by said detection circuit while said blowing circuit does not supply a current to the unit.

5. The image forming device according to claim 1 , wherein

said blowing circuit is configured to supply a current to said unit containing the non-blown component instead of a fuse when operation of said blowing circuit for said unit has not been checked in the past.

6. The image forming device according to claim 5 , wherein

said controller includes a storage unit for storing a history of checking operation of said blowing circuit.

7. The image forming device according to claim 1 , wherein

said non-blown component is a resistance element.

8. A method of checking operation of an image forming device with a mounted replaceable unit, said image forming device including an interface capable of mounting any one of a first type unit containing a fuse for indicating whether the unit is in a first state or a second state, and a second type unit containing a non-blown component instead of the fuse in the first type unit, said method comprising the steps of:

specifying, after said replaceable unit is mounted on said image forming device, whether the mounted unit is of the first type or the second type;

detecting, when it is specified that the first type unit has been mounted, a potential varying depending on whether or not the fuse has been blown by a detection circuit forming a circuit together with the fuse contained in the unit;

determining whether the mounted first type unit is in said first state or said second state based on the detected potential;

supplying a current for blowing the fuse contained in the unit from a blowing circuit when the mounted first type unit is in said first state;

checking operation of said blowing circuit based on potentials detected before current supply and after current supply, respectively, at said detection circuit including the fuse contained in the mounted first type unit;

determining whether or not operation of said blowing circuit has been checked in the past when it is specified that the second type unit has been mounted;

supplying a current to the non-blown component contained in the mounted second type unit from said blowing circuit when operation of said blowing circuit has not been checked in the past; and

checking 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 before current supply and after current supply, respectively, said detection circuit forming a circuit together with the non-blown component contained in the mounted second type unit.

9. A non-transitory storage medium storing an operation checking program to be executed by an image forming device with a mounted replaceable unit, said image forming device including an interface capable of mounting any one of a first type unit containing a fuse for indicating whether the unit is in a first state or a second state, and a second type unit containing a non-blown component instead of the fuse in the first type unit, said operation checking program comprising:

instructions for specifying, after said replaceable unit is mounted on said image forming device, whether the mounted unit is of the first type or the second type;

instructions for obtaining, when it is specified that the first type unit has been mounted, a potential varying depending on whether or not the fuse has been blown from a circuit including the fuse contained in the unit;

instructions for determining whether the mounted first type unit is in said first state or said second state based on the obtained potential;

instructions for causing a blowing circuit to supply a current for blowing the fuse contained in the unit when the mounted first type unit is in said first state;

instructions for checking operation of said blowing circuit based on potentials before current supply and after current supply, respectively, obtained from the circuit including the fuse contained in the mounted first type unit;

instructions for determining whether or not operation of said blowing circuit has been checked in the past when it is specified that the second type unit has been mounted;

instructions for supplying a current to the non-blown component contained in the mounted second type unit from said blowing circuit when operation of said blowing circuit has not been checked in the past; and

instructions for checking operation of said blowing circuit based on potentials detected before current supply and during current supply, respectively, or potentials detected before current supply and after current supply, respectively, at a circuit including the non-blown component contained in the mounted second type unit.