Gerät und Methode zur Informationsdetektion

摘要

An information detection apparatus is disclosed. A plurality of probes are arranged in the apparatus so as to face a medium which carries an information. Each of the plurality of probes produces a detection signal from the medium. A performance testing device is provided in the apparatus for testing the performance of each of the plurality of probes. A detection device in the apparatus selects the signal from at least one normal probe on the basis of the test result of the testing device and detects the information in accordance with the selected signal. By such the construction in the apparatus, the detection of the information can be continuously effected even if one of the probes is broken. <IMAGE>