| 摘要 |
PURPOSE:To improve detection precision for edge pinholes by a simple constitution by tilting an optical filter to the surface of a detected belt body in a fixed direction as to inspection of the opaque belt body. CONSTITUTION:The edges of detection object 1 are fixed and light sources 241 and 242, and photoelectric converting methods 191 and 192 are provided; and swing- stop rollers 231 to 233 are arranged on the reverse surface side of the object and light penetrating the pinhole at the edge part of object 1 is detected by each photoelectric converting method 19 to detect the existence of a pinhole. The long axis of each light source 24 is made parallel to the endge part of object 1 and between the edge of object 1 and photoelectric converting methods 19, optical filters 211 and 212 are arranged. The surfaces confronting to edges of both optical filters 21 is so tilted that reflected from each light source 24 will fall on the outside of the edge. Therefore, projection light off the edge is removed and precision of the detection of the pinhole can be improved. |
