| 摘要 |
The present invention is intended to effect proper sealing of a film 26 by automatically adjusting the gripping pressure exerted by seal bars 29, 30 on the basis of a change in unsteady current flowing through the seal bars which grip the film. When the main shaft 42 of a servomotor 41 mounted on a frame 33 is rotated forward and backward, the pair of seal bars 29, 30 open and close with respect to each other. When the seal bars 29, 30 press each other, the film 26 is gripped under pressure by these seal bars and heat-sealed. Cushion means for elastically pressing the seal bars increases the gripping pressure of the pair of seal bars in proportion to an increase in the angle of rotation of the main shaft 42 of the motor 41 after the opposed surfaces of the seal bars have contacted each other. A controller 61 decreases the sealer gripping pressure when the current is high and produces a large amount of heat in filaments 70 stuck to the opposed surfaces of the seal bars but increases the sealer gripping pressure when the current is low and produces a smaller amount of heat in the filaments. |
