OPTICALLY INSPECTING THE POSITION AND SIZE OF MAGNETIC STRIPES ON A MOVABLE WEB

1343798 Inspecting photo-sensitive webs ILFORD Ltd 12 July 1972 [ 2 Aug 1971] 36181/71 Heading G2J [Also in Division F2] An inspection device for inspecting the location of applied marks or magnetic stripes on a travelling transparent photo-sensitive web 1 comprises a translucent rotatable roller 2, over which, in use, the web is arranged to pass, the roller having an axially positioned light source 3 giving light which does not affect the photosensitive web (e.g. by the effect of filter 5), and there being positioned on the other side of the web, in use, a microscope 8 so located to provide an enlarged view of a portion of the web at the eye-piece. Illuminated graticule 10 maybe projected into the microscope field of view by semi-reflector 9. The web may be arranged to run in a fixed position by a flange on the roller, or by co-operation with a straight edge separate from the roller, the straight edge being wearresistant e.g. of aluminium oxide ceramic (Fig. 2) not shown.