Welding device and welding method

Abstract

The present invention provides a welding device and a welding method for reducing the un-welded portion of a sheet blank and a strip-shaped member. The welding device of the present invention includes: a pair of pressure members for pressurizing the sheet blank and the strip-shaped member; a feeding device for intermittently or continuously feeding the sheet blank and the strip-shaped member through the pair of pressure members; and a laser device for irradiating a laser beam onto the sheet blank or the strip-shaped member upstream of the pair of pressure members. The welding device may include a moving device that moves the pair of pressure members upstream relative to the sheet blank and the strip-shaped member when the feeding stops. Alternatively, the feeding device may be replaced by the following: the feeding device retracts the sheet blank and the strip-shaped member to a certain length and then stops the sheet blank and the strip-shaped member.

Description

Technical Field

[0001] The present disclosure relates to an apparatus and method for welding a continuous strip-shaped member to a sheet material web, and more particularly to welding using a laser beam and pressure. Background Art

[0002] As disclosed in Patent Documents 1 to 4, there are bag-making machines that sequentially manufacture plastic bags using a continuous bag material and a continuous zipper. The bag-making machine includes a welding device that welds the bag material and the zipper together.

[0003] The welding device of Patent Document 1 and Patent Document 2 includes a pressure roller pair, a feeding device and a laser device. The pressure roller pair faces each other to pressurize the bag material and the clip chain. The feeding device intermittently feeds the bag material and the clip chain along their length direction in a state of mutual overlap through the pressure roller pair. The laser device irradiates the laser beam toward the clip chain upstream of the pressure roller pair.

[0004] When the laser beam hits the zipper, the irradiated portion is heated and melted by the laser beam. The bag material and zipper are then guided to the pressure roller pair and overlapped. As they pass between the pressure roller pair, they are pressurized and welded together.

[0005] The temperature of the irradiated portion decreases during the time it takes from the laser beam irradiation position to the pressure roller pair. In order to achieve proper welding, the irradiated portion must remain molten until it reaches the pressure roller pair.

[0006] The bag material and zipper are fed intermittently. That is, the bag material and zipper are fed and stopped repeatedly. When the intermittent feeding stops, the irradiated portion in the area from the irradiation position to the pressure roller pair cools and returns from a molten state to a non-melted state. Therefore, when the bag material and zipper are fed again, the irradiated portion is squeezed into the bag material by the pressure roller pair in a non-melted state, and as a result, it is not welded to the bag material. In this way, despite laser irradiation and pressure, unmelted portions are generated during each intermittent feeding. When making bags, the unmelted portions can cause leaks, affecting the quality of the plastic bags and possibly causing material loss.

[0007] In the welding devices of Patent Documents 3 and 4, the feeding device feeds the bag material and zipper continuously, rather than intermittently, so the aforementioned problem does not occur. However, when the welding device stops operating, the feeding device stops feeding the bag material and zipper. Consequently, the irradiated portion, located between the laser beam irradiation position and the pressure roller pair, cools and returns to an unmelted state. When the welding device resumes operation and the feeding device resumes feeding the bag material and zipper, the irradiated portion passes between the pressure roller pair in an unmelted state, resulting in an unmelted portion.

[0008] An object of the present disclosure is to provide an apparatus and method capable of shortening the unwelded portion.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent No. 6023293

[0012] Patent Document 2: Japanese Patent No. 5619268

[0013] Patent Document 3: WO2019 / 097942

[0014] Patent Document 4: WO2016 / 163487 Summary of the Invention

[0015] According to one embodiment of the present disclosure, a welding device for welding a sheet blank and a continuous strip-shaped member to each other is provided. The welding device includes: a pair of pressure members facing each other to apply pressure to the sheet blank and the strip-shaped member; a feeding device that intermittently feeds the sheet blank and the strip-shaped member along their lengths so that they pass between the pair of pressure members in a superimposed state; a laser device that irradiates a laser beam upstream of the pair of pressure members to melt the sheet blank or the strip-shaped member, thereby achieving welding of the sheet blank and the strip-shaped member; and a moving device that moves the pair of pressure members upstream relative to the sheet blank and the strip-shaped member when the intermittent feeding stops.

[0016] When the intermittent feeding stops, the moving device can move the pair of pressing members upstream from the reference position and return to the reference position.

[0017] When the intermittent feeding is stopped, the moving device may move the pair of pressing members upstream in such a manner that at least one of the pressing members enters a path of the laser beam.

[0018] According to another embodiment of the present disclosure, a welding device includes: a pair of pressure members facing each other to pressurize a sheet blank and a strip-shaped member; a feeding device that intermittently feeds the sheet blank and the strip-shaped member along their lengths so that they pass between the pair of pressure members in a superimposed state; and a laser device that irradiates a laser beam upstream of the pair of pressure members to melt the sheet blank or the strip-shaped member, thereby achieving welding of the sheet blank and the strip-shaped member. Furthermore, the feeding device feeds the sheet blank and the strip-shaped member by a first length during one cycle of intermittent feeding, and then retracts them by a second length, which is shorter than the first length, and stops.

[0019] The welding device may further include a tension maintaining mechanism provided upstream of the pair of pressing members and configured to maintain tension on the sheet material.

[0020] The second length may be equal to or less than the distance between the irradiation position of the laser beam and the pressing position of the pressing member pair.

[0021] According to another embodiment of the present disclosure, the welding device includes: a pair of pressure members facing each other to pressurize the sheet blank and the strip member; a feeding device to continuously feed the sheet blank and the strip member along their length direction in a mutually overlapping state through between the pressure member pairs; a laser device to irradiate the sheet blank or the strip member with a laser beam upstream of the pressure member pair and melt the sheet blank or the strip member by the laser beam to achieve welding of the sheet blank and the strip member; and a moving device to move the pressure member pair upstream relative to the sheet blank and the strip member when the feeding device stops the sheet blank and the strip member.

[0022] According to another embodiment of the present disclosure, a welding device includes: a pair of pressure members facing each other to pressurize a sheet blank and a strip-shaped member; a feeding device to continuously feed the sheet blank and the strip-shaped member along their lengths, passing between the pair of pressure members in a superimposed state; and a laser device that irradiates a laser beam upstream of the pair of pressure members to melt the sheet blank or the strip-shaped member, thereby achieving welding of the sheet blank and the strip-shaped member. Furthermore, the feeding device is configured to stop the sheet blank and the strip-shaped member after retracting a certain distance.

[0023] According to another embodiment of the present disclosure, a welding method for welding a sheet blank and a continuous strip-shaped member to each other is provided, the method comprising: intermittently feeding the sheet blank and the strip-shaped member in a mutually overlapping state through a pair of pressure members along their length direction; irradiating the sheet blank or the strip-shaped member upstream of the pair of pressure members with a laser beam and melting the sheet blank or the strip-shaped member by the laser beam to achieve welding of the sheet blank and the strip-shaped member, the sheet blank and the strip-shaped member being pressurized by the pair of pressure members when passing between the pair of pressure members and being welded to each other; when the intermittent feeding stops, the pair of pressure members is moved upstream from a reference position relative to the sheet blank and the strip-shaped member, the sheet blank and the strip-shaped member are pressurized by the moved pair of pressure members and are welded to each other, and then the pair of pressure members is returned to the reference position.

[0024] According to another embodiment of the present disclosure, the cladding method is as follows: the sheet blank and the strip-shaped member are intermittently fed along their length direction in a state of mutual overlap through a pair of pressure members; a laser beam is irradiated onto the sheet blank or the strip-shaped member upstream of the pair of pressure members to melt the sheet blank or the strip-shaped member by the laser beam to achieve cladding of the sheet blank and the strip-shaped member; within a cycle of intermittent feeding, the sheet blank and the strip-shaped member are fed a first length, and are retracted to a second length shorter than the first length and stopped.

[0025] The pair of pressurizing members may be a pair of pressurizing rollers. The sheet material may be a continuous bag material for bags. The strip-shaped member may be a continuous clip chain for bags. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1A 1 is a schematic top view of a bag making machine including an exemplary welding device. Figure 1B for Figure 1A Schematic side view of a bag making machine.

[0027] Figure 2A This is a schematic cross-sectional view of an exemplary strip member (clip chain). Figure 2B A schematic top view of an example bag.

[0028] Figure 3 To represent locally Figure 1B Side view of the welding device.

[0029] Figure 4A Example of welding method, Figure 4B The relationship between the feed speed and the irradiation intensity is shown below.

[0030] Figure 5A 、 Figure 5B Example of welding method.

[0031] Figure 6A 、 Figure 6B Example of welding method.

[0032] Figure 7A FIG. 1 is a side view partially showing another exemplary welding device. Figure 7B The relationship between the feed speed and the irradiation intensity is shown below.

[0033] Figure 8A 、 Figure 8B Another welding method will be described as an example.

[0034] Figure 9 The tension maintaining mechanism is schematically shown.

[0035] Figure 10A FIG. 1 is a schematic top view of a bag making machine including another exemplary welding device. Figure 10B for Figure 10A Schematic side view of a bag making machine.

[0036] Figure 11A 、 Figure 11B Here is another example of a welding method.

[0037] Figure 12 Here is another example of a welding method.

[0038] Figure 13A The structure for moving the laser device is illustrated. Figure 13B This section illustrates an example of a camera equipped on a laser device.

[0039] Figure 14A A pillow bag making machine including a welding device is schematically illustrated. Figure 14B To locally represent the bag Figure 14A Magnified view of area T.

[0040] Figure 15A 、 Figure 15B Another pillow bag making machine is exemplified.

[0041] [Explanation of Symbols]

[0042] 1: Sheet blank (bag material)

[0043] 2: Strip components (clip chain)

[0044] 20: Surface to be welded

[0045] 3: Pressing roller pair as a pressurizing member pair

[0046] 4: Feeding device

[0047] 5: Laser device

[0048] 50: Laser beam

[0049] 6: Mobile mechanism

[0050] 7: Bag

[0051] 9: Tension maintaining mechanism

[0052] P: Reference position of the pressure roller pair (pressure member pair)

[0053] Y: Feed direction / length direction of film

[0054] θ: irradiation angle DETAILED DESCRIPTION

[0055] Hereinafter, a welding device and a welding method according to an embodiment will be described with reference to the accompanying drawings. In each embodiment, the same or similar components are denoted by the same reference numerals and their description will be omitted.

[0056] [First embodiment]

[0057] Figure 1A 、 Figure 1B The bag-making machine is schematically shown. The welding device of the embodiment is equipped in the bag-making machine. The welding device welds a continuous strip-shaped member 2 to a sheet material 1 (i.e., a continuous sheet material). The strip-shaped member 2 has a width smaller than that of the sheet material 1.

[0058] like Figure 2A 、 Figure 2B As shown, in the embodiment, the sheet blank 1 is a continuous plastic film, specifically, a continuous bag material that becomes the bag material of the bag 7. In the embodiment, the strip member 2 contains plastic and is a continuous zipper that becomes the zipper of the bag 7. The strip member 2 of the embodiment has two surfaces 20 to be welded on both sides thereof. As in patent document 1, the zipper as the strip member 2 includes a male material 21 and a female material 22 that are interlocked with each other in a detachable manner. The male material 21 has one surface 20, and the female material 22 has another surface 20. Hereinafter, the strip member 2 (zipper) is fed and welded to the sheet blank 1 in a state in which the male material 21 and the female material 22 are interlocked with each other.

[0059] like Figure 1A 、 Figure 1B As shown, the welding device includes a pair of pressure rollers 3 as a pair of pressure members, which face each other to press the two sheet materials 1 and the strip-shaped member 2. As described later, the sheet materials 1 and the strip-shaped member 2 are pressed by the pressure roller pair 3 and welded to each other.

[0060] The welding device also includes a feeder 4 that intermittently feeds the sheet material 1 and the strip-shaped member 2 in their longitudinal direction (their continuous direction) by superimposing them together and passing them between a pair of pressure rollers 3 in the superimposed state. Thus, the sheet material 1 and the strip-shaped member 2 are repeatedly fed and stopped by the feeder 4. The symbol Y in the figure indicates the feeding direction when the sheet material 1 and the strip-shaped member 2 are fed in the superimposed state.

[0061] The feeding device 4 includes at least one pair of drive rollers 40, located downstream of the pressure roller pair 3, to intermittently feed the sheet material 1 and the strip-shaped member 2. The drive roller pair 40 rotates while sandwiching the sheet material 1 and the strip-shaped member 2, thereby intermittently feeding the sheet material 1 and the strip-shaped member 2 as they pass between the pressure roller pair 3 and the drive roller pair 40. For convenience, only one pair of drive roller pairs 40 is shown in the figure. However, larger machines typically include multiple pairs of drive rollers 40, all of which are driven synchronously during the intermittent conveyance of the sheet material 1 and the strip-shaped member 2.

[0062] The feed device 4 also includes guide rollers 41 for guiding the sheet blanks 1 to the pressure roller pairs 3. The sheet blanks 1 are continuously unwound from a roll using known methods. Alternatively, a wide sheet blank is continuously unwound from a roll and split lengthwise into two sheet blanks 1. The sheet blanks 1 are then appropriately switched from continuous feeding to intermittent feeding by a floating roller mechanism (not shown). The guide rollers 41 are positioned downstream of the floating roller mechanism. The sheet blanks 1 are guided by the guide rollers 41 to the pressure roller pairs 3.

[0063] The feeding device 4 further includes a guide roller 42 and a guide body 43 ( Figure 1B ), the guide roller 42 and the guide body 43 ( Figure 1B ) is used to guide the strip-shaped member 2 to the pressure roller pair 3. The strip-shaped member 2 is fed from the material roll and is introduced between the two sheet blanks 1 before being superimposed. The guide roller 42 changes direction in the direction Y and is fed to the pressure roller pair 3 through the guide body 43.

[0064] Thus, the sheet material 1 and the belt-like member 2 are superimposed on each other just before the pressing position of the pressure roller pair 3. At this time, one surface 20 of the belt-like member 2 contacts the sheet material 1, and the other surface 20 contacts the other sheet material 1. Thus, the sheet material 1 and the belt-like member 2 are fed through the space between the pressure roller pair 3 in a superimposed state.

[0065] like Figure 1B 、 Figure 3As shown, the welding device also includes two laser devices 5, and the two laser devices 5 irradiate the strip-shaped member 2 with a laser beam 50 to melt the strip-shaped member 2 through the laser beam 50. As in Patent Documents 1 and 2, the laser device 5 includes a laser light source and an optical system. One laser device 5 is configured to irradiate the laser beam 50 to one surface 20 of the strip-shaped member 2, and the other laser device 5 is configured to irradiate the laser beam 50 to the other surface 20 of the strip-shaped member 2. As in Patent Documents 1 and 2, the laser devices 5 are respectively configured to irradiate the laser beam 50 to the strip-shaped member 2 at an irradiation angle θ (0<θ≤90). As Figure 2A As shown, the surface 20 of the strip-shaped member 2 is formed with a light-absorbing layer 23 that absorbs the laser beam 50. As a result, the surface 20 absorbs the laser beam 50, generates heat, and melts. The wavelength of the laser beam 50 is appropriately selected. For example, it can be visible light or infrared light.

[0066] As in Patent Document 1, when using a laser beam 50 for welding with intermittent feeding, the laser device 5 links the irradiation intensity of the laser beam 50 with the feed speed of the sheet material 1 to achieve uniform weld strength. The irradiation intensity is increased when the sheet material 1 is fed at high speed, while it is reduced when the sheet material 1 is fed at low speed. In other words, the laser device 5 is configured to irradiate the laser beam 50 while controlling the irradiation intensity of the laser beam 50 according to the feed speed.

[0067] An example of this is shown in Figure 4B . In mode 1, the irradiation intensity is completely proportional to the feed speed, and when the feed speed is zero, the irradiation intensity is zero (and therefore the laser beam 50 is not irradiated). On the other hand, in mode 2, the irradiation intensity is proportional to the feed speed, but the irradiation intensity is controlled in such a way that it is not less than the prescribed minimum value W1 (0<W1<W2, W2 is the irradiation intensity when the feed speed is maximum). Therefore, the laser beam 50 is continuously irradiated not only when the sheet blank 1 is being fed, but also when the sheet blank 1 has stopped. The laser device 5 sets the output to zero in mode 1, but does not set the output to zero in mode 2. Generally speaking, the laser device 5 is subjected to the greatest load when it outputs from a zero output state, so the load on the laser device 5 in mode 2 is smaller than that in mode 1, which is more ideal.

[0068] like Figure 3 As shown, laser beam 50 irradiates surface 20 (light-absorbing layer 23), and surface 20 is heated and melted by laser beam 50. Then, sheet material 1 and strip-shaped member 2 are superimposed on each other, with molten surface 20 contacting sheet material 1, and pass between pressure roller pair 3. Sheet material 1 and strip-shaped member 2 are pressed by pressure roller pair 3 as they pass between pressure roller pair 3. As a result, one sheet material 1 is welded to one surface 20, and the other sheet material 1 is welded to the other surface 20. As is well known, to ensure welding, surface 20 must be pressed against sheet material 1 by pressure roller pair 3 while still welded.

[0069] The welding device also includes a moving device 6 that moves the pressure roller pair 3 downstream (in the feed direction Y) and upstream (in the opposite direction). The moving device 6 may include, for example, a supporting member that rotatably supports both ends of the rotation axis of each pressure roller pair 3, a guide that supports the supporting member so that it can be guided in the feed direction Y and the opposite direction, and an actuator that moves the supporting member along the guide. The operation of the actuator enables the supporting member and the pressure roller pair 3 to move together upstream and downstream along the guide. The moving device 6 is not limited to this example.

[0070] As described below, the moving device 6 moves the pressure roller pair 3 in conjunction with the intermittent feeding of the feeding device 4 . Figure 4A Irradiation with a laser beam 50 is shown. Figure 4A Only one sheet of blank 1 and one pressing roller 3 are shown. Figure 4A The end portion of the line L1 formed by the laser beam 50 and the start portion of the line L2 to be irradiated are separated. Figure 4A As shown, a laser beam 50 having a spot-shaped cross section 500 passes near the portion of the sheet material 1 that engages with the pressure roller 3 and is irradiated at an irradiation angle θ onto the surface 20 of the strip-shaped member 2. The irradiated surface 20 then reaches a predetermined reference position P, where it is pressed against the sheet material 1 by the pressure roller pair 3.

[0071] Figure 5A The display time is t1 (refer to Figure 4B ) is the moment when the sheet material 1 and the strip-shaped member 2 stop. Furthermore, the hatched portion of line L1 represents the welded portion. In section PS, the surface 20 is irradiated with the laser beam 50 and melted, but has not yet been welded to the sheet material 1.

[0072] like Figure 5B As shown, when the sheet blank 1 and the strip-shaped member 2 stop, the pressure roller pair 3 moves upstream (to the right of the drawing) from the reference position P to the position P' relative to the sheet blank 1 and the strip-shaped member 2 with the help of the moving device 6. While the pressure roller pair 3 moves in the interval P-P', it presses the sheet blank 1 toward the surface 20 in the fused state, thereby pressuring the sheet blank 1 and the strip-shaped member 2 to weld them to each other for a distance d in the interval P-P'. Then, while the sheet blank 1 and the strip-shaped member 2 stop (to the position P'), the pressure roller pair 3 presses the sheet blank 1 toward the surface 20 in the fused state, thereby pressuring the sheet blank 1 and the strip-shaped member 2 to weld them to each other for a distance d in the interval P-P'. Figure 4B The moving device 6 returns the pressure roller pair 3 to the reference position P).

[0073] Then, at time t2, the feed device 4 begins feeding the sheet material 1 and the strip-shaped member 2. The laser beam 50 irradiates the surface 20 at the irradiation position (section QS), and the portion of the surface 20 in section QS is molten. Meanwhile, the portion of the surface 20 in section P'-Q has returned from a molten state to a non-molten state. As a result, this portion of the surface 20, although pressurized by the pressurizing roller pair 3 when passing between the pressurizing roller pair 3, does not fuse to the sheet material 1. In other words, a region of approximately length c is created where the sheet material 1 and the strip-shaped member 2 are completely non-fused to each other, i.e., the non-fused region. Furthermore, the non-fused region, which remains unfused despite laser irradiation and pressure, has a length equivalent to the distance of section P'-R (due to the spot shape of the cross-section 500 of the laser beam 50, the portion of the surface 20 in section QR is partially melted and partially non-fused). Of this non-fused region, the downstream portion of length c constitutes the non-fused region defined above.

[0074] Thus, when intermittent feeding stops, the moving device 6 moves the pressure roller pair 3 upstream from the reference position P by a distance d and then returns to the reference position P. Thus, the sheet material 1 and the strip-shaped member 2 are pressed by the moving pressure roller pair 3, and are welded to each other over a distance d. The upstream movement of the pressure roller pair 3 must occur before the surface 20 returns from a molten state to a non-molten state. Therefore, the moving device 6 preferably begins upstream movement of the pressure roller pair 3 immediately after feeding stops. During each intermittent feeding, the pressure roller pair 3 is moved by the moving device 6 as described above.

[0075] The welding device of Patent Document 1 does not include the moving device 6, so a length b ( Figure 5B That is, the welding device and welding method of the embodiment can shorten the unwelded portion by the moving distance d (=b-c) of the pressure roller pair 3 .

[0076] In the laser device 5, for example, Figure 4B The curve of the irradiation intensity of mode 2 is shown as follows: when the laser beam 50 is continuously irradiated, Figure 6AAs shown, the pressure roller pair 3 can also be moved by the moving device 6 in a manner that respectively enters the path of the laser beam 50. When the intermittent feeding stops, the laser beam 50 is prevented from being irradiated toward the surface 20 by the pressure roller 3. That is, when the intermittent feeding stops, the surface 20 is prevented from being continuously irradiated by the laser beam 50 and becoming an over-molten state within the interval QS. Therefore, at least the portion of the pressure roller 3 that presses the sheet blank 1 and the strip-shaped member 2 is preferably formed of a material that reflects the laser beam 50. For example, the pressure roller pair 3 can be moved from the reference position P to the position R. The surface 20 is in a fused state within the interval PS, so the sheet blank 1 and the strip-shaped member 2 are thereby fused to each other within the interval PR. In addition, the pressure roller pair 3 can also be moved from the reference position P to the position S so that the sheet blank 1 and the strip-shaped member 2 are fused to each other within the interval PS.

[0077] like Figure 6A As shown, laser beam 50 is irradiated onto the portion of sheet material 1 that engages with pressure roller 3. However, this irradiation location is not the focal point of the laser beam, and its energy is also weak. In the embodiment, sheet material 1 is transparent to laser beam 50 (no light-absorbing layer is provided), so sheet material 1 is not damaged by laser beam 50.

[0078] like Figure 6B As shown, just before the start of feeding of the sheet blank 1 and the strip-shaped member 2 (just before t2), the pressure roller pair 3 returns to the reference position P through the moving device 6. At this time, a portion of the sheet blank 1 is still in the path of the laser beam 50. However, as mentioned above, the laser beam 50 will pass through the sheet blank 1, so it will irradiate the surface 20 of the strip-shaped member 2 and heat the surface 20 to melt it. If the moving distance d is increased, it is possible to achieve welding with almost no un-welded area / portion or zero un-welded area / portion. Furthermore, the moving distance d is sufficient to be the distance from the reference position P to the position S (upstream end of the irradiation position) at most.

[0079] In the embodiment, a pressure of approximately 2N to 3N is sufficient for welding. A large pressure roller pair is not required. For example, the pressure roller pair 3 is preferably made of a lightweight material such as carbon. This material selection allows the pressure roller pair 3 to be easily moved relative to the sheet material 1 and the strip-shaped member 2.

[0080] As disclosed in various patent documents, the irradiation angle θ is appropriately determined. From the perspective of increasing irradiation intensity (preventing blurring), the irradiation angle θ is preferably 90° or close to 90°. On the other hand, when the irradiation angle θ is large, the irradiation position moves away from the pressure roller pair 3, thereby increasing the unwelded portion. Therefore, the irradiation angle θ is, for example, 10° to 80°, more specifically 15° to 60°. This also applies to the following embodiments.

[0081] The coordinated operation of the feeding device 4, the laser device 5, and the moving device 6 is achieved using a control device (including a controller, etc.) not shown.

[0082] As mentioned above, the welding device is incorporated into the bag making machine. Figure 1A 、 Figure 1B As shown, the bag making machine further includes a sealing device 80, a sealing device 81 and a cutting device 82. After welding, the two bag body materials (sheet blanks) 1 are sealed to each other along one side thereof by the sealing device 80 to form a sealing portion 70 ( Figure 2B ). In addition, the bag material 1 is sealed with each other along its width direction by the sealing device 81 to form a sealing portion 71 ( Figure 2B ). These seals can be heat-sealed or ultrasonically sealed. The bag material 1 and the zipper (strip-like member) 2 are cut along their width by a cutting device 82, thereby forming a bag 7. The cutting can be in the form of shearing or melting. In this embodiment, the bag 7 is a plastic bag.

[0083] The bag making machine may also be a multi-row output type that forms two or more bags 7 each time the bag material 1 and the zipper 2 are cut by the cutting device 82. The bag making machine may partially seal the bag material (sheet blank) 1 and the zipper (strip-shaped member) 2 and flatten the zipper 2 to form flattened portions 72 ( Figure 2B ). As disclosed in Patent Document 4, the flattened portion 72 ensures the airtightness of the bag 7 at the end of the clip 2. The bag making machine preferably forms the flattened portion 72 in such a way that the unwelded range / part described above is included in the flattened portion 72. This can reduce material loss. It can also be replaced by the following content Figure 2B For example, when the unwelded portion is short, the flattened portion 72 can be completely contained within the sealed portion 71. During bag manufacturing, the unwelded portion can cause leaks, affecting bag quality and potentially resulting in material loss. Therefore, the welding device is particularly advantageous when incorporated into a bag-making machine.

[0084] [Second embodiment]

[0085] like Figure 7A As shown, the welding device of this embodiment does not include the moving device 6 ( Figure 3 The driving roller pair 40 of the feeding device 4 can rotate freely in forward and reverse directions. Figure 7B The relationship between the feed speed and the irradiation intensity of this embodiment is shown. Figure 7BAs shown in the feed speed curve, during one cycle of intermittent feeding, the feed device 4 rotates the drive roller pair 40 forward to feed the sheet material 1 and the strip-shaped member 2 in the feed direction Y by a first length. The drive roller pair 40 then rotates backward to retract the sheet material 1 and the strip-shaped member 2 by a second length, which is shorter than the first length. The drive roller pair 40 then stops, bringing the sheet material 1 and the strip-shaped member 2 to a stop. The feed device 4 intermittently feeds the sheet material 1 and the strip-shaped member 2 using the method described above during each cycle. Therefore, if the intermittent feeding clear pitch is represented by p, the first length is represented by f1, and the second length is represented by f2, then p = f1 - f2 (f1 > f2).

[0086] Hereinafter, the laser device 5 is exemplified as follows: Figure 7B The operation of the welding device and the welding method when the curve of mode 1 changes.

[0087] Figure 8A The display time is t1( Figure 7B ) is the moment when the laser beam 50 ceases irradiation. At this point, the sheet material 1 and the strip-shaped member 2 have been fed in the direction Y by the clearance p, and thus, have been mutually welded to the clearance p. Surface 20 has been irradiated with the laser beam 50 within the interval PS and is therefore in a welded state.

[0088] Then, the feeding device 4 rotates the driving roller pair 40 further in the positive direction without stopping, and feeds the sheet material 1 and the strip-shaped member 2 further in the direction Y by the second length f2. Figure 8A The section PP' of the surface 20 is fed to the press roller pair 3 and pressed against the sheet material 1 by the press roller pair 3. Thus, the sheet material 1 and the strip-shaped member 2 are additionally welded to each other by the press roller pair 3 over a length of about f2.

[0089] Then, the feed device 4 reverses the driving roller pair 40 to retract the sheet material 1 and the strip-shaped member 2 by the length f2, and stops the driving roller pair 40 to stop the sheet material 1 and the strip-shaped member 2. As a result, the additional welded portion returns to the interval P-P' ( Figure 8B ).

[0090] Then, at time t2, the next cycle of intermittent feeding begins.

[0091] As is clear from the above, this embodiment can shorten the unwelded portion by a retraction length f2 (second length). By setting length f2, it is possible to reduce the unwelded area / portion to essentially zero. It is sufficient that length f2 is less than or equal to interval PS (the distance between the pressing position of the pressing roller pair 3 and the irradiation position of the laser beam 50 (more specifically, the upstream end thereof)).

[0092] By length f2, such as Figure 8BAs shown, a portion of the sheet material 1 may enter the path of the laser beam 50. As described above, the sheet material 1 is not damaged by the laser beam 50 and does not prevent the laser beam 50 from being irradiated to the surface 20 of the belt-shaped member 2.

[0093] As described above, the pressing force of the pressing roller 3 can be a relatively small value of about 2 N to 3 N. Therefore, the retracting operation of the sheet material 1 and the belt-shaped member 2 can be achieved without any problem.

[0094] like Figure 9 As shown, the welding device of the embodiment may include a tension maintaining mechanism 9 (hereinafter referred to as the maintaining mechanism). The maintaining mechanism 9 can be set for each side of the sheet blank 1. The maintaining mechanism 9 is set on the pressure roller pair 3 ( Figure 7A ) upstream, more specifically, provided on the guide roller 41 (refer to Figure 1A 、 Figure 1B ) and downstream of the floating roller mechanism. The maintaining mechanism 9 is configured to maintain the tension of the sheet blank 1. The maintaining mechanism 9 adopts a known mechanism. For example, the maintaining mechanism 9 includes an imparting roller 90, two guide rollers 91, an actuator 92 and a sensor not shown in the figure, the imparting roller 90 is used to impart tension, the two guide rollers 91 are arranged upstream and downstream of the imparting roller 90, the actuator 92 moves the imparting roller 90 in the direction Z, and the sensor detects the position of the imparting roller 90. The maintaining mechanism 9 adjusts the position of the imparting roller 90 by operating the actuator 92 according to the detection of the sensor to maintain a certain degree of tension. A maintaining mechanism 9 can also be provided for the strip-like component 2, which is arranged upstream of the irradiation position of the laser beam 50 and is configured to maintain the tension of the strip-like component 2. The maintaining mechanism 9 connects the feeding device 4 to Figure 7B The feed speed curve absorbs the change in tension of the sheet material 1 and the strip-shaped member 2 when the sheet material 1 and the strip-shaped member 2 are fed intermittently.

[0095] In the above embodiment, the laser device 5 is Figure 7B The laser beam 50 is intermittently irradiated according to the irradiation intensity curve of the mode 1, but the laser beam 50 may be continuously irradiated. Therefore, the laser device 5 may be configured to irradiate the laser beam 50 according to the irradiation intensity curve of the mode 1. Figure 7B The laser beam 50 is irradiated according to the irradiation intensity curve of the mode 2. In this case, the unwelded portion can also be shortened.

[0096] In the above-described embodiment, the feed device 4 and the laser device 5 are also controlled by the control device so as to operate synchronously.

[0097] [Third embodiment]

[0098] Figure 10A 、 Figure 10BA bag-making machine including the welding device of this embodiment is shown. In this embodiment, the drive roller pair 40 of the feeding device 4 of the welding device rotates continuously, feeding the sheet material 1 and the strip-shaped member 2 continuously, rather than intermittently, along their longitudinal direction Y. The bag-making machine includes another drive roller pair 84, located downstream of the drive roller pair 40. The drive roller pair 84 intermittently feeds the sheet material 1 and the strip-shaped member 2 along their longitudinal direction Y. Therefore, in this embodiment, the dancer roller mechanism 83 is located downstream of the drive roller pair 40 and upstream of the drive roller pair 84, enabling a smooth transition from continuous to intermittent feeding.

[0099] The feed device 4 continuously feeds the sheet material 1 and the strip-shaped member 2 at a constant feed speed. The strip-shaped member 2 (its surface 20) is melted by the laser beam 50 upstream of the pressure roller pair 3. The sheet material 1 and the strip-shaped member 2 are then superimposed on each other and pressurized by the pressure roller pair 3, thereby fusing them together. This is similar to Patent Documents 3 and 4.

[0100] As in the first embodiment, the welding device of the embodiment includes a moving device 6. When the feeding device 4 receives a feed stop input while continuously feeding the sheet material 1 and the strip-shaped member 2 in the positive direction Y, the driving roller pair 40 is stopped to stop the sheet material 1 and the strip-shaped member 2. Figure 11A 、 Figure 11B As shown, when the feed device 4 stops the sheet material 1 and the strip-shaped member 2, the moving device 6 moves the pressure roller pair 3 upstream from the reference position P to a position P' relative to the sheet material 1 and the strip-shaped member 2 by a distance g, and then returns to the reference position P. As a result, the sheet material 1 and the strip-shaped member 2 are mutually welded by the moving pressure roller pair 3 within the interval P-P' over a distance g.

[0101] Thereafter, when the feed device 4 receives the input of the start of feeding, the feeding of the sheet blank 1 and the strip-shaped member 2 is resumed. The laser device 5 irradiates the surface 20 with the laser beam 50 in the interval QS. On the other hand, the portion of the interval P'-Q of the surface 20 was in a molten state due to the previous irradiation of the laser beam 50, but it has cooled and returned to a non-molten state when the feeding is resumed. Therefore, the portion of the interval P'-Q of the surface 20 is not melted when the feeding is resumed. As a result, an unmelted range of length c is generated, but the length c is shorter than the length b of the unmelted range generated in the previous device and method by the moving distance g (c=b-g). That is, the present embodiment can also shorten the unmelted portion. As in the first embodiment, when the moving distance g is increased, the length of the unmelted range / portion can be reduced, and it is possible to substantially reduce it to zero.

[0102] [Fourth embodiment]

[0103] The welding device of the embodiment does not include the moving device 6. The feeding device 4 continuously feeds the sheet blank 1 and the strip-shaped member 2 along the length direction thereof. When the feeding device 4 receives an input to stop feeding, the sheet blank 1 and the strip-shaped member 2 are stopped, and after receiving an input to stop feeding, the sheet blank 1 and the strip-shaped member 2 are retreated by a length h and then stopped. That is, the feeding device 4 switches the driving roller pair 40 from forward rotation to reverse rotation to retreat the sheet blank 1 and the strip-shaped member 2 by a length h, and then stops the driving roller pair 40 to stop the sheet blank 1 and the strip-shaped member 2. Thus, when the sheet blank 1 and the strip-shaped member 2 stop, as shown Figure 12 As shown, the welded portion of the sheet material 1 and the strip-shaped member 2 returns by a length h upstream of the pressure roller pair 3. That is, the welded portion is located within the section PP'.

[0104] Next, when the feed device 4 receives the start-of-feed input and resumes feeding the sheet blank 1 and strip-shaped member 2, an unwelded area of length c is generated, similar to the third embodiment. This unwelded area length c is shorter than the conventional unwelded area length b by approximately length h (c = b - h). Thus, this embodiment also shortens the unwelded area. As in the second embodiment, increasing the retraction length h can reduce the length of the unwelded area / portion, potentially reducing it to essentially zero.

[0105] As mentioned above, although the preferred embodiment of the present invention was described, the present invention is not limited to the embodiment.

[0106] In each embodiment, the laser beam 50 is irradiated onto the strip-shaped member 2. Alternatively, the sheet material 1 may include a light-absorbing layer, and the laser beam 50 may be irradiated onto the sheet material 1 to weld the sheet material 1 and the strip-shaped member 2 to each other.

[0107] In various embodiments, Figure 13A As shown, the laser device 5 is fixed on a base shaft 85, and the base shaft 85 can be supported on a base not shown in the figure. The base can be movable in the feed direction Y and the opposite direction relative to the pressure roller pair 3 together with the base shaft 85. The base shaft 85 can be supported on the base in a manner that it can move in the width direction X of the sheet blank 1 relative to the pressure roller pair 3. The base shaft 85 can be supported on the base in a manner that it can also move in the direction Z at right angles to the direction X and the direction Y relative to the pressure roller pair 3. The base shaft 85 can be supported on the base in a manner that it can rotate around its axis (direction Φ). Thus, the position and orientation of the laser device 5 can be freely adjusted, so that the irradiation position and irradiation angle θ of the laser beam 50 can be freely adjusted (refer to Figure 3 wait).

[0108] There are several factors that must be adjusted to irradiate the strip-shaped member 2 with the laser beam 50. It is desirable to minimize the factors that require user adjustment. Therefore, it is preferable to provide the welding device as a product to the user with the directions Y, Z, and Φ (and therefore the irradiation angle θ and irradiation distance) pre-adjusted and fixed. This is because during welding, the user only needs to adjust the irradiation position in the width direction X of the sheet material 1. This is convenient for the user.

[0109] The laser device 5 may have a function of irradiating a weak-power visible light laser beam 50. By using such a laser beam 50 as an indicator before welding, the user can easily adjust and confirm the irradiation position in advance.

[0110] like Figure 13B As shown, the camera 86 can be mounted on the laser device 5 so that the irradiation position of the laser beam 50 is included in its imaging range. In addition, the image of the camera 86 can be displayed in real time on the display. The user can confirm the irradiation of the laser beam 50 in real time at a position away from the laser beam 50.

[0111] like Figure 13A As shown, the pressure roller 3 includes a portion 30 for applying pressure to the sheet material 1 and the strip-shaped member 2, and a portion 31 adjacent to portion 30. The pressure roller 3 is typically made of carbon, in which case portion 30 is preferably thicker than portion 31. Alternatively, only portion 30 may be made of a material, such as metal, that is more rigid than carbon. If portion 30 is made of carbon, the problem arises: it bends during pressure application, deforming into an elliptical cross-section. This structure solves this problem.

[0112] Carbon absorbs the laser beam 50. Therefore, the surface of the pressure roller 3, where the laser beam 50 passes, should preferably have a color that reflects the laser beam 50. Examples of such colors are white or silver. For example, a foil made of a material such as aluminum that reflects the laser beam 50 can be attached or wrapped around the body of the pressure roller pair 3. If the sheet material 1 is transparent to the laser beam 50, the carbon of the pressure roller 3 may absorb the laser beam 50 and generate heat, potentially heating the sheet material 1. This structure solves this problem.

[0113] The welding device of each embodiment is incorporated into Figure 1A 、 Figure 1B or Figure 10A 、 Figure 10B But it can also be incorporated into other types of bag making machines. For example, the melting device can also be incorporated into Figure 14A In the pillow bag making machine.

[0114] like Figure 14AAs shown, in a pillow bag making machine, a continuous bag material 1 (sheet blank) is fed intermittently or continuously along its longitudinal direction Y. It is guided by a known bag material guide mechanism (not shown), and one side portion 10 and the other side portion 11 are bent into a cylindrical shape so as to face each other. Furthermore, the one side portion 10 and the other side portion 11 are guided by the bag material guide mechanism to the pressure roller pair 3. Figure 2A The clip chain 2 (strip-shaped member) is also guided between the one side portion 10 and the other side portion 11 by the guide roller 42 and the guide body 43, and is thereby guided between the pressure roller pair 3. Thus, the one side portion 10, the other side portion 11, and the clip chain 2 are superimposed on each other and fed through the pressure roller pair 3 in a superimposed state. The two laser devices 5 are arranged upstream of the pressure roller pair 3 to project laser light onto both surfaces 20 ( Figure 2A ) irradiates laser beam 50.

[0115] Therefore, one side portion 10 of the bag material 1 and one surface 20 of the zipper 2 are welded to each other by the pressure roller pair 3 , and at the same time, the other side portion 11 of the bag material 1 and the other surface 20 of the zipper 2 are welded to each other by the pressure roller pair 3 .

[0116] Thereafter, the one side portion 10 and the other side portion 11 can be sealed together along their length direction by the sealing device 87 at a position closer to the edge than the clip 2. Although not shown in the figure, the contents are then filled into the bag material 1, and the bag material 1 is sealed in its width direction to form a sealed portion 73. Subsequently, the bag material 1 and the clip 2 are cut in their width direction. Thus, a bag is formed. Figure 14A 、 Figure 14B The plastic bag 7' shown is preferably included in the sealing portion 73 when the unwelded portion described above is produced.

[0117] Figure 15A or Figure 15B The pillow bag making machine shown in the example manufactures plastic bags 7' without clip chains. In the embodiment, the surface of one side portion 10 facing the other side portion 11 is formed by a light absorbing layer. A laser device 5 irradiates the surface with a laser beam 50 to melt the surface. The one side portion 10 and the other side portion 11 are pressurized by the pressure roller pair 3 and welded (sealed) to each other. In the embodiment, only one laser device 5 is required, and the downstream sealing device 87 ( Figure 14A ) can be omitted. Therefore, the bag making machine as a whole can be miniaturized and simplified.

[0118] like Figure 15A As shown, the laser beam 50 can be irradiated from the inner side of the bag material 1 to one side portion 10. In addition, if the other side portion 11 is transparent to the laser beam 50, the laser beam 50 can also be irradiated as shown in FIG. Figure 15BAs shown, the laser beam 50 is irradiated to one side portion 10 through the other side portion 11. For this purpose, for example, the other side portion 11 includes a material having high transparency to the laser beam 50 and is printed with a highly transparent dye.

[0119] The sheet material 1 may also include, for example, a paper base and a film or resin material instead of a plastic film, the film or resin material being partially or entirely laminated on the paper base. The sheet material 1 may also include any one or more materials as long as the sheet material 1 has a surface capable of being welded to the strip-shaped member 2 at least partially.

[0120] The strip-shaped member 2 may be, for example, a male member of a zipper, a female member of a zipper, a male member of a Velcro, a female member of a Velcro, a Velcro comprising male and female members that engage with each other, an adhesive tape, a sealing tape, a strip of reinforcing material, a strip of decorative material, a strip of a bag label, etc., rather than a zipper in which the male material 21 and the female material 22 are interlocked. The strip-shaped member 2 may be composed of any one or more materials as long as it has at least partially a surface capable of being welded to the sheet blank 1.

[0121] The pair of pressing members 3 is not limited to a pair of pressing rollers, and other structures may also be used.

[0122] The welding device is not limited to being incorporated into the bag making machine, but can also be incorporated into other devices.

Claims

1. A welding device for welding a sheet material and a continuous strip member to each other, characterized in that: include: a pair of pressurizing members facing each other to pressurize the sheet blank and the strip-shaped member; a feeding device for intermittently feeding the sheet blank and the strip-shaped member along their length direction so that the sheet blank and the strip-shaped member pass between the pair of pressing members in a mutually superimposed state; a laser device that irradiates the sheet blank or the strip-shaped member with a laser beam upstream of the pair of pressing members to melt the sheet blank or the strip-shaped member by the laser beam, thereby achieving welding between the sheet blank and the strip-shaped member; as well as The moving device moves the pressing member pair upstream from a reference position relative to the sheet material and the strip member by a distance less than the distance from the reference position to the upstream end of the laser beam irradiation position when the intermittent feeding is stopped, and returns to the reference position.

2. The welding device according to claim 1, characterized in that When the intermittent feeding stops, the moving device moves the pair of pressing members upstream in such a manner that at least one of the pressing members enters the path of the laser beam. At least a portion of the pressing member that presses the sheet material and the belt-shaped member is formed of a material that reflects the laser beam.

3. A welding device for welding a sheet material and a continuous strip member to each other, characterized in that: include: a pair of pressurizing members facing each other to pressurize the sheet blank and the strip-shaped member; a feeding device for intermittently feeding the sheet blank and the strip-shaped member along their length direction so that the sheet blank and the strip-shaped member pass between the pair of pressing members in a mutually superimposed state; as well as a laser device that irradiates the sheet material or the strip-shaped member with a laser beam upstream of the pair of pressing members, thereby melting the sheet material or the strip-shaped member with the laser beam to achieve welding between the sheet material and the strip-shaped member; During a cycle of intermittent feeding, the feeding device feeds the sheet blank and the strip-shaped member by a first length and retracts them by a second length and stops, wherein the second length is shorter than the first length and is less than the distance between the irradiation position of the laser beam and the pressing position of the pressing member pair.

4. The welding device according to claim 3, characterized in that The invention further includes a tension maintaining mechanism that is provided upstream of the pair of pressing members and is configured to maintain tension on the sheet material.

5. A welding device for welding a sheet material and a continuous strip member to each other, characterized in that: include: a pair of pressurizing members facing each other to pressurize the sheet blank and the strip-shaped member; a feeding device for continuously feeding the sheet blank and the strip-shaped member along the longitudinal direction thereof so that the sheet blank and the strip-shaped member pass between the pair of pressing members in a mutually superimposed state; a laser device that irradiates the sheet blank or the strip-shaped member with a laser beam upstream of the pair of pressing members to melt the sheet blank or the strip-shaped member by the laser beam, thereby achieving welding between the sheet blank and the strip-shaped member; as well as A moving device that moves the pressing member pair upstream from a reference position relative to the sheet blank and the strip-shaped member by a distance less than the distance from the reference position to the upstream end of the laser beam irradiation position when the feeding device stops the sheet blank and the strip-shaped member, and returns to the reference position.

6. A welding device for welding a sheet material and a continuous strip member to each other, characterized in that: include: a pair of pressurizing members facing each other to pressurize the sheet blank and the strip-shaped member; a feeding device for continuously feeding the sheet blank and the strip-shaped member along the length direction thereof so as to pass between the pair of pressing members in a mutually superimposed state; as well as a laser device that irradiates the sheet material or the strip-shaped member with a laser beam upstream of the pair of pressing members, thereby melting the sheet material or the strip-shaped member with the laser beam to achieve welding between the sheet material and the strip-shaped member; The feeding device is further configured to stop the sheet material and the belt-shaped member after retreating by a length equal to or less than the distance between the irradiation position of the laser beam and the pressing position of the pair of pressing members.

7. The welding device according to any one of claims 1 to 6, wherein: The pair of pressing members is a pair of pressing rollers.

8. A welding method for welding a sheet material and a continuous strip member to each other, characterized in that: The sheet material and the strip-shaped member are intermittently fed along the longitudinal direction thereof so as to pass between the pair of pressing members in a mutually superimposed state. irradiating the sheet material or the strip-shaped member with a laser beam upstream of the pair of pressing members to melt the sheet material or the strip-shaped member by the laser beam, thereby achieving welding between the sheet material and the strip-shaped member; When the intermittent feeding stops, the pressure member pair is moved upstream from the reference position relative to the sheet blank and the strip member to a distance less than the distance from the reference position to the upstream end of the laser beam irradiation position, and the sheet blank and the strip member are pressurized by the moved pressure member pair and melted to each other, and then the pressure member pair is returned to the reference position.

9. A welding method for welding a sheet material and a continuous strip member to each other, characterized in that: The sheet material and the strip-shaped member are intermittently fed along the longitudinal direction thereof so as to pass between the pair of pressing members in a mutually superimposed state. irradiating the sheet material or the strip-shaped member with a laser beam upstream of the pair of pressing members to melt the sheet material or the strip-shaped member by the laser beam, thereby achieving welding between the sheet material and the strip-shaped member; In one cycle of intermittent feeding, the sheet blank and the strip-shaped member are fed a first length and retracted to a second length and stopped, wherein the second length is shorter than the first length and is less than the distance between the irradiation position of the laser beam and the pressing position of the pressing member pair.

10. The welding method according to claim 8 or 9, characterized in that: The sheet material is a continuous bag material for bags. The strip-shaped member is a continuous clip chain for the bag.

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