A process for manufacturing bags made of a biodegradable or biodegradable-compostable plastic material and without any bellows, said process comprising the following sequence of steps: loading a reel (12) of plastic film (13) obtained by blown-film extrusion and having a width which corresponds to the width of at least one bag (50) to be formed; longitudinally cutting along cutting lines (15) to form at least two longitudinal bands (13); separating the bands to a given D distance from each other, and longitudinally welding; said steps being a function of the transversal dimension or width of the bag to be manufactured; transversally welding each individual longitudinal band (13) to define band portions (27) which corresponds to the longitudinal dimensions of the bags (50) to be formed, punching said band portions (27), moving and unloading the bags (50) thus formed.

A controller for a pouch-making machine for manufacturing a pouch while feeding a pair of film materials each provided with a reference mark that indicates a reference position for layering the film materials together, includes a driven roller shift unit for independently shifting each shaft of a pair of driven rollers that rotate being driven by the pair of film materials being fed and a control unit for controlling the driven roller shift unit based on a result of an image-shooting unit shooting images of the reference marks, so that positions of the reference marks provided on the pair of film materials coincide.

A tape includes, in a cross-sectional shape: a first and a second portion which are configured to be at least partially in opposition. The first portion includes: thick portions provided in corresponding one of a first and a third region, out of the first, a second, and the third region in a width direction of the tape; a first and a second thin portion provided at respective both end portions, in the width direction, of the second region positioned between the first and the third region; and at least one intermediate portion provided between the first and the second thin portion. The second portion includes: thick portions provided in corresponding one of the first and the third region and extending beyond end portions, in the width direction, of the second region; and at least one third thin portion provided in the second region and opposed to the intermediate portion.

Provided is a production method for a freshness-keeping bag capable of reducing the inflow of oxygen from the outside of the bag to a very low level, and thereby keeping the freshness of a content thereof for a long period of time. The present invention provides a method for producing a freshness-keeping bag formed of a film, wherein the freshness-keeping bag has a band-shaped joining region in which two ends of the film are overlapped and joined together, the joining region comprising a plurality of joined parts in which the two ends of the film are joined together, and a non-joined part which is located between adjacent ones of the joined parts and in which the overlapped ends of the film are not joined together, the non-joined part composing a non-linear ventilation passage communicating between an internal space of the bag and the outside of the bag, the method comprising the step of forming the joined parts by ultrasonic welding, wherein the step of forming the joined parts includes continuously forming the joined parts in the film, while rotating a disk-shaped ultrasonic welding anvil with respect to the film, wherein the ultrasonic welding anvil has a plurality of protrusions formed on an outer periphery thereof continuously at given intervals and correspondingly to the configuration of the joined parts of the bag.

A web of first or second material is provided with the spout, and a plastic bag is made from side gusset materials in addition to webs of the first and second materials. An aperture is formed in the web of the first or second panel material, and the spout is inserted into and positioned with the aperture, whenever the webs of the first and second panel materials are fed intermittently. After the webs of the first and second panel materials are superposed on each other, whenever the webs of the first and second panel materials are fed intermittently, the webs of the first and second panel materials are heat sealed with each other in a longitudinal direction thereof by a longitudinal seal device, and the webs of the first and second panel materials are heat sealed with the side gusset materials in a width direction thereof by a cross seal device.

The product efficiency of bags each with an end face part is increased. A panel webs is guided to be divided along a line of weakness of the panel web and to be folded along division edges of the panel web. This guiding of the first panel and temporary sealed sections cause a side gusset to be cut open along a line of weakness of the side gusset such that open surfaces are formed. After the forming of the open surfaces, an end face web is supplied to be superposed on folded parts of the panel web and the open surfaces of the side gusset.

At least one of a horn or an anvil includes protrusions that protrude from a facing surface thereof. Two panel parts and a gusset part folded and interposed between the panel parts are sandwiched and compressed by the horn and the anvil. Two portions of the gusset part are welded to each other by ultrasonic vibration of the horn during the sandwiching and compressing.

A thermal welder is configured to weld a back seam of a bag formed of thermoplastic sheet material. The welder may include a weld heater and a compression mechanism downstream of the weld heater to compress the sheet material to form the back seam. The welder may also include a weld breaker downstream of the compression mechanism to break apart incidental welds which are formed adjacent the back seam.

A thermal welder is configured to weld a back seam of a bag formed of thermoplastic sheet material. The welder may include a weld heater and a compression mechanism downstream of the weld heater to compress the sheet material to form the back seam. The welder may also include a weld breaker downstream of the compression mechanism to break apart incidental welds which are formed adjacent the back seam.

A controller for a pouch-making machine for manufacturing a pouch while feeding a pair of film materials each provided with a reference mark that indicates a reference position for layering the film materials together, includes a driven roller shift unit for independently shifting each shaft of a pair of driven rollers that rotate being driven by the pair of film materials being fed and a control unit for controlling the driven roller shift unit based on a result of an image-shooting unit shooting images of the reference marks, so that positions of the reference marks provided on the pair of film materials coincide.