Patent ID: 6958603

Claim:
A metallic contaminant detecting method comprising the steps of: conveying an inspection object contained in a package along a conveyance path to detect a metallic contaminant accidentally mixed in said inspection object during a manufacturing process; and detecting step of detecting the metallic contaminant mixed in said inspection object by generating a magnetic field from a detecting element provided in an intermediate portion of said conveyance path, said detecting element having a coil comprising a core and a conductor wound around said core; generating a small magnetic field by applying a voltage to said coil or supplying an electric current to said coil, and detecting a detection magnetic field generated from said metallic contaminant in response to said small magnetic field as a detection voltage or a detection current of said coil, and then outputting a detection signal; analyzing said detection signal to identify said metallic contaminant, wherein said small magnetic field is created by applying a small voltage to said coil or supplying a small electric current to said coil and using a non-linear portion of magnetic field characteristics of said core constituting said coil; and magnetizing said metallic contaminant in said conveyance path by a magnet booster comprising magnet elements before said metallic contaminant detecting step, wherein said magnet booster comprises at least two constituent parts disposed at respective positions facing each other across said conveyance path, and wherein said magnet elements forming said two constituent parts are disposed in such a manner that like magnetic poles thereof face toward said conveyance path.