| 摘要 |
PURPOSE:To securely heat-seal an unsealing tape at a specified position, by measuring the film tension, adjusting the braking volume of the wound-off shaft of the film according to the measured figure, and keeping the value in a certain range. CONSTITUTION:The speed of a film belt 4 between a roll of film 5 and a nip- roller 3 is almost constant. An adjuster 1 of braking volume is fitted at the roll of film 5 to regulate the braking force action on the wound-off shaft 13 of the rolled film. A tension detector 2 is for the film tension between the roll of film 5 and the nip-roller 3 and the tension is detected by a detecting means such as a strain gauge fitted at the rotary shaft. The detected value of the tension detector 2 is transmitted to the adjuster 1 of the braking volume as a signal and the adjuster 1 regulates the braking force of the wound-off shaft 13 basing on the detected value. When the braking force of the wound-off shaft 13 increases, the tension between the roll of film 5 and the nip-roller 3 increases and when the braking force decreases, the tension decreases also. In this way, the sealing position of the unseal tape becomes constant.
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