Foreign-matter detector and foreign-matter detecting system

A foreign-matter detecting system comprising:

• a transport conveyor;
• and
• a foreign-matter detector for detecting foreign matter contained in articles of different kinds transported between a transmitter for generating a magnetic field and a receiver for receiving magnetic fluxes in the generated magnetic field, said detector comprising:
• a signal extractor for extracting a signal having a predetermined phase difference relative to a transmitted signal from the transmitter, based on a phase of the transmitted signal from the transmitter and the received signal from the receiver, the transmitted signal being for generating the magnetic field and the received signal being induced by the magnetic fluxes;
• a specific value setting unit for setting, through an external manual input operation, a specific value for the level of the extracted signal which is attributable to the articles free from foreign matter to be detected and is specified for each kind of the articles;
• and
• a level adjusting circuit for automatically adjusting the signal extractor or the receiver to cause the level of the extracted signal attributable to the article itself to assume the specific value inputted based on a difference between the specific value and a predetermined fixed value lower than a level of determination of the foreign matter by which level the presence or absence of the foreign matter is determined wherein, the foreign-matter detector detects the presence or absence of the foreign matter contained in the articles being transported by the transport conveyor.

A foreign-matter detector comprising:

• a signal extractor extracting a signal having a predetermined phase difference relative to a transmitted signal from a transmitter, based on a phase of the transmitted signal from the transmitter and a received signal from a receiver, the transmitted signal being for generating a magnetic field and the receiving signal being induced by magnetic fluxes in the generated magnetic field;
• a specific value setting unit setting, through an external input manual operation, a specific value for the level of the extracted signal which is attributable to articles free from foreign matter to be detected and is specified for each kind of the articles;
• and
• a level adjusting circuit automatically adjusting the signal extractor or the receiver to cause the level of the extracted signal attributable to the articles to assume the specific value inputted based on a difference between the specific value and a predetermined fixed value lower than a level of determination of the foreign matter by which level the presence or absence of the foreign matter is determined.

A foreign-matter detecting system comprising:

• a transport conveyor;
• and
• a foreign-matter detector, said detector comprising:
• a signal extractor extracting a signal having a predetermined phase difference relative to a transmitted signal from a transmitter, based on a phase of the transmitted signal from the transmitter and a received signal from a receiver, the transmitted signal being for generating a magnetic field and the receiving signal being induced by magnetic fluxes in the generated magnetic field;
• a specific value setting unit setting, through an external manual input operation, a specific value for the level of the extracted signal which is attributable to articles free from foreign matter to be detected and is specified for each kind of the articles;
• and
• a level adjusting circuit automatically adjusting the signal extractor or the receiver to cause the level of the extracted signal attributable to the article to assume the specific value inputted based on a difference between the specific value and a predetermined fixed value lower than a level of determination of the foreign matter by which level the presence or absence of the foreign matter is determined wherein, the foreign-matter detector detects the presence or absence of the foreign matter contained in the articles being transported by the transport conveyor.