| 摘要 |
An improved indexing vacuum-packaging machine more accurately positions and aligns the upper film relative to the lower film at the sealing station. A video camera replaces a conventional photocell, whereby the braking and concomitant stretching of the upper film at the sealing station need only be performed only every few indexing cycles, whereby shaking and jerking of the machine is negated as compared to a conventional vacuum-packaging machine. The video camera may use any portion of the printed matter on the upper film as a target for determining when to brake the upper film for the subsequent stretching thereof, without having to rely solely upon the hithertofore-used one black target-box imprinted on the upper film. The video camera is focused on a section of the portion of upper film at the sealing station for detecting a predetermined target area of printed matter, which section to be detected may form any part of the printed matter, and is not limited to, and preferably not, the one black target-box located longitudinally centrally between each longitudinally repeating pattern of printed matter on the upper surface-face of the upper film. When the target image-area has been detected by the video camera apparatus and the software thereof, an output signal is generated to cause the braking mechanism of the vacuum-packaging machine at the sealing station to be actuated to brake the upper film that will stretch the upper film.
|
