Abstract: A bag making apparatus includes a welding device for welding a sheet panel and a strip member in a zone where the sheet panel is intermittently fed by a feed device and a cut device disposed downstream of the welding device to cross-cut the sheet panel and the strip member every intermitted feed cycle. The welding device include a pressure unit for pressurizing the sheet panel and the strip member superposed on each other and a laser unit for irradiating the sheet panel or the strip member with a laser beam at an irradiation position upstream of a pressure position of the pressure unit to melt the sheet panel or the strip member. The pressure unit and the laser unit are configured to be movable together upstream and downstream relative to the sheet panel while maintaining a relative positional relationship between the pressure position and the irradiation position.

Abstract: 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.

Abstract: A welding device includes a pair of pressure rollers for pressurizing a web and a strip member, a feed device configured to intermittently or continuously feed the web and the strip member through the pair of pressure rollers, and the laser device configured to irradiate the web or the strip member with a laser beam at a position upstream of the pair of pressure rollers. The welding device may include a movement device configured to move the pair of pressure rollers upstream with respect to the web and the strip member during pause or stop of feed. Alternatively, the feed device may pause or stop the web and the strip member after retracting the web and the strip member by a certain length.

Abstract: A welding device includes a pair of pressure rollers for pressurizing a web and a strip member, a feed device configured to intermittently or continuously feed the web and the strip member through the pair of pressure rollers, and the laser device configured to irradiate the web or the strip member with a laser beam at a position upstream of the pair of pressure rollers. The welding device may include a movement device configured to move the pair of pressure rollers upstream with respect to the web and the strip member during pause or stop of feed. Alternatively, the feed device may pause or stop the web and the strip member after retracting the web and the strip member by a certain length.