Abstract: A packing material feeding apparatus for a vertical-type bag form-fill-sealing machine comprises a feeding device for feeding a web as a packing material along a filling tube at a constant velocity during a normal operation of the machine, and a controller for controlling the operation of the feeding device. When a filling operation of articles is absent, the controller reduces a web feeding velocity, and then accelerates the web feeding velocity to the constant velocity when filling of the articles is resumed afterward. The acceleration of the web is carried out using a period equal to or longer than a unit packing period which is required to produce one bag during the normal operation of the machine.

Abstract: A vertical sealing device for a packing machine includes a pair of feed units for feeding a cylindrical-formed packaging material and a center heat sealer for the heat-sealing of a vertical seam of the packaging material. When the operation of the machine is halted, the feed units feed the packaging material from a steady speed mode to a deceleration mode. During this deceleration mode, the operation of the center heat sealer is stopped. On the other hand, when the operation of the packing machine is restarted, the feed units feed the packaging material in an acceleration mode, and during this acceleration mode, the center heat sealer starts operating.