Abstract: A method of detecting tape defects according to a light amount signal obtained from the surface of a tape by scanning the width of the tape surface with a light beam is disclosed. The light beam is caused to scan beyond the tape edges. The light amount signal is differentiated to obtain a light amount differential signal. A tape defect in the vicinity of the tape edge is detected if the light amount differential signal has a level different from a predetermined reference level or if the point in time when a change in the level of the light amount differential signal is different from a predetermined point in time.

Abstract: A joint inspection apparatus comprises a light irradiating device for irradiating light to a tape joint at which two tape edge portions are joined together, and a light receiving device for receiving the light irradiated by the light irradiating device to the tape joint and passing through the tape joint or reflected by the tape joint. A judgment device is provided for judging the size of a gap between the two tape edge portions at the tape joint on the basis of information on the optical amount of the light received by the light receiving device in the vicinity of the tape joint.