Abstract: A form-fill-seal machine has a forming structure, a vertical seal structure, and a clamp fixing mechanism. The forming structure has a support frame, a tube, a sailor collar-shaped unit, and an anvil. The tube is fixed to the support frame. The sailor collar-shaped unit is fixed to the support frame, and wraps a sheet-shaped film around the tube so that two ends thereof overlap. The anvil is fixed to the tube. The vertical seal structure has an oscillator. The oscillator generates ultrasonic waves in order to seal overlapping portions of two ends of the film, being conveyed through the intervening gap with the anvil, in a vertical direction. The clamp fixing mechanism fixes the forming structure and the vertical seal structure in fixed positions relative to one another.

Abstract: A form-fill-seal machine 100 has a pull-down belt mechanism 23, a vertical sealing mechanism 2, and a controller 29. The pull-down belt mechanism conveys a cylindrical film Fm. The vertical sealing mechanism applies pressure and ultrasonic oscillation to the cylindrical film which is conveyed by the pull-down belt mechanism, and seals the cylindrical film. The controller controls the pull-down belt mechanism, and the pressure and the amplitude of the ultrasonic oscillation applied to the cylindrical film by the vertical sealing mechanism. The controller applies pressure and ultrasonic oscillation to the cylindrical film immediately before reaching a first point in time when the cylindrical film begins to be conveyed. The controller changes at least one of the pressure and the amplitude of the ultrasonic oscillation applied to the film according to the speed of the film in a time period after reaching the first point in time.