Current through heating element lower than resistance suggests
The lamp in the fuser is most probably a halogen lamp. The resistance of such a lamp in a cold condition is low. However the moment the lamps starts to glow the resistance goes up very steeply. The 5A of the lamp corresponds to 1150 W. The resistance of the fuser lamp in a hot condition is therefore 46 ohms. If you want to make your own fuser heater then you would need a 46 ohm resistance in the hot condition. But I do not consider this a good idea even if it works. First of all the mass of your heater is much more so it will take much more time to warm up. Secondly I doubt whether your own solution can be made safe enough for the environment you are working with.

In theory an impedance changes due to AC. However with the frequency involved you can ignore that. It is simply the fuser lamp resistance that has such a steep rise in resistance. This lamp has also a high current during start up like all incandecent lamps. It is also the reason that lamps mostly fail during switching on.