| 摘要 |
PURPOSE:To judge the quality of a can product filled with food or the like quickly and accurately by a method wherein a light wave including a laser beam or an electromagnetic wave is applied around the can product and the reflective power is electrically processed. CONSTITUTION:A can product 1 is filled with food 2 such as soup. A laser beam from a laser oscillator 3 reaches the prescribed position of the center of a lid 1b of the can product 1 through a prism mirror 4 which forms a light pulse, a round mirror 5 and a hood 6. The reflective light is tansmitted through a reflector 8 and converted into an electric signal by a photoelectric conversion element 7 and put into a signal comparator as the status data of the can product to be compared and processed with a reference signal from a reference signal generator. If the signal of the height of the top edge of a frame 1a is used as the reference signal and the signal of the height of the center of the lid 1b is used as the signal to be compared and the differential signal A is obtained, the pressure inside the can be measured and it can be detected whether the can is filled with the required quantity of nitrogen gas. |
