| 摘要 |
A device for measuring the heat-seal position of a plastic film (4) being fed in a fixed direction and having a heat-seal part (18) where a mesh pattern of micro protrusions and recesses are provided on its surface. A light source (23) and an optical sensor (24) are opposed to the plastic film (4), and a shielding plate (26) is interposed between the optical sensor and the plastic film. The shielding plate (26) has a small hole or a narrow slit for passing light. Light is emitted from the light source (23), light reflected from or passing through the plastic film (4) is passed through the small hole or narrow slit of the shielding plate (26) and directed to the optical sensor (24), through which image recognition is performed using the reflected light. Micro protrusions and recesses on the surface of the heat-seal part (18) are detected from the variation of the image, and the heat-seal position of the plastic film (4) can be determined. <IMAGE> |
