Abstract: The stretch film for rustproof stretch packaging has an appropriate roll tack and sufficient self-tack to adhere to and package an object, such as a steel coil. This stretch film has an overall density of 0.870 to 0.935 g/cm3 and is composed of polyolefin resin, rust preventive agents, and an effective amount of a polyolefin polyol adhesive with a number average molecular weight of 500 to 5,000 g/mol. When the film has at least three layers, one surface layer has a density of 0.850 to 0.920 g/cm3, and another surface lever on the opposite side of the film and intermediate layers between them have greater densities. The polyolefin polyol adhesive and the rust preventive agents are present at least in the low density surface layer.

Abstract: A method for inspecting bags having folded and pasting bottoms. Light source is provided to irradiate a bottom of a moving bag with a light so that shadows appear along a shape of bottom folds. A CCD linear array image sensor takes an image of the bottom of the bag from the reflected light and delivers electric signal corresponding to the image. The electrical signal are processed to extract a shape of bottom folds based on the shadows on the irradiated bottom. The obtained outer profile is compared with a reference input of a good bag stored in a memory to emit an electric selection signal classifying whether it is a good product or a defective product.

Abstract: An automatic stretch-wrapping apparatus for wrapping a load, including empty PET bottles, with a stretchable film. The apparatus includes a turntable for placing the load thereon, and the stretchable film is supplied from a roll of stretchable film in a vertical position via film tensioning rollers to a gripper device. The gripper device is mounted on the turntable for gripping the leading end of the film and can rotate not only with the turntable but also relative to the turntable. Also, a swing arm device is arranged for movement toward and away from the gripper device to cooperate with the gripper device and includes pusher blades for pushing the film toward the gripping fingers of the gripper device, a heatsealer, and a cutter. It is possible to automatically wrap the load by the film in only one turn thereof.

Abstract: An unwrapping apparatus for unwrapping a palletized and stretch-wrapped load, including at the front side thereof lower grippers and upper grippers to grip the lower edge and upper edge of a stretchable film of the load, respectively, and a cutter unit for vertically cutting the stretchable film. The unwrapping apparatus includes at the rear side thereof a carriage having a platen to press the top of a load, a pair of swing arms carrying the upper grippers, and a pair of auxiliary film separating swing arms to separate the stretchable film from the rear corner portions of the load when the film is removed from the load by the main swing arms. The main swing arms and the auxiliary swing arms prevent the articles from being pulled and moved by the stretchable film in contact with the articles and thus falling down from the separate sheet in particular.

Abstract: An unwrapping apparatus for unwrapping a palletized and stretch-wrapped load, the apparatus enables the prevention of the articles from falling off and easy disposal of the used stretchable film. The apparatus comprises first and second upright frames between which a load to be unwrapped is conveyed, the first upright frame including two lower grippers for gripping a lower edge of the stretchable film, and an elevated cutter unit having two pairs of pinch rollers and a heat cutter. The second upright frame includes a carriage having a platen to press the top of the load to be unwrapped and a pair of swing arms symmetrically arranged on either side of the platen and extending toward the first upright frame. Upper grippers are secured to the swing arms, respectively. The stretchable film can be gripped during the cutting and unwrapping of the load to maintain tension and prevent the articles in the load from falling off. In addition, the used stretchable film can be discharged in a compressed, compact form.

Abstract: In a process for manufacturing sacks of sheet material, flat tubes are fed one by one in the direction perpendicular to the discharging direction thereof, while the tubes are overlapped or shingled as offset by a predetermined distance. The tubes are wound one by one on a reel core with the help of a tape, which is connected at one end thereof to the reel core and continuously supplied with the rotation of the reel core. The tubes are secured on the reel core outside pressure supplied by the tape to form a tube wound reel having a desired diameter. After a certain time period and immediately before the susequent bottom-closing process, the tubes are unwound from the reel core by pulling the tape to rotate the reel. The overlapped tubes are then separated from each other and supplied one by one to a bottom-closing station.

Abstract: The air in a bag which has been filled with a content is first removed by pressing to flatten the surface of the bag. The bag is then transported and supported in such a manner that it assumes an arc shape having a fixed curvature with which the convex surface of the bag is permitted to be opposed to the convex surface of a printing plate at a position just below said plate. Under these conditions, the surface of the bag is clearly printed. The apparatus for effecting the printing method of the present invention comprises a pressing device for pressing the bag, a printing plate mounted on a plate cylinder of a rotary letter press and detector for causing the plate cylinder to be rotatively driven and the rotation thereof to be stopped.