Apparatus for detecting a gap in the junction area on a folded box

Abstract

An apparatus for detecting a gap in the junction area on a folded box which is made of a sheet of smooth corrugated fiberboard by folding the latter while both the folded ends are located opposite to one another with the gap interposed therebetween. The apparatus includes detectors which are disposed along the moving track of the folded box. Each of the detectors includes a slit formed on the moving track at a substantially right angle relative to the latter, the width of the slit being dimensioned more than that of the gap in the junction area on the box, two inclined passages formed in the detector to reach the slit, each of the inclined passages having the substantially same inclination angle relative to the moving track, a light beam emitting mechanism disposed in one of the inclined passages to emit light beam toward the slit and a number of optical fibers longitudinally disposed in the other inclined passage so as to allow reflected light beam to be transmitted therethrough. According to the invention it is possible to detect abnormality relative to quality of the folded box and moreover carry out monitoring in the course of many steps of production. When an incorrectly folded box is detected, it is removed from the production line by operating a removing device which can be operatively associated with an automatic control system. Thus, maintaining high quality of products and saving of manpower are assured.