Bag making machine and bag making method

Abstract

A bag making machine and a bag making method are provided. The bag making machine includes: an intermittent conveying device for intermittently conveying a body piece; an adjustment device for detecting an upper threshold value and a lower threshold value of a length of the body piece included in an interval from a first drive roller pair to a second drive roller pair; and a moving device for moving a processing device and a sensor as a movable group integrally along a length direction of the body piece. The moving device moves the movable group upstream in response to the adjustment device detecting the upper threshold value, and moves the movable group downstream in response to the adjustment device detecting the lower threshold value. In a case where the movable group is moved, the intermittent conveying device determines an intermittent conveying distance based on not only an output from the sensor but also a moving distance of the movable group, and conveys the body piece by the first drive roller pair by the determined intermittent conveying distance.

Description

Technical Field

[0001] This application relates to a bag-making machine and a bag-making method for sequentially manufacturing bags using at least two sheet-like body parts. Background Technology

[0002] The bag-making machine and method described above are disclosed, for example, in Patent Documents 1-3. At least two sheet-like body parts are intermittently conveyed. During each intermittent conveying, the sheet-like body parts are processed. For example, the body parts are heat-sealed along their width direction by a transverse sealing device and cross-cut along their width direction by a cross-cutting device. Each time a cross-cut is performed, a bag is formed.

[0003] Sometimes, body parts with patterns repeatedly printed at printing intervals are used. When manufacturing bags with printed patterns, it is important that the body part (its printed pattern) be aligned with high precision relative to processing devices such as lateral sealing devices and cross-cutting devices when intermittent transport is temporarily stopped. When the body part is processed in a position deviating from the design (e.g., heat sealing, cross-cutting), the quality or appearance of the bag may deteriorate.

[0004] During various processes such as heat sealing, the printing spacing of the main body component may vary locally and over time due to environmental conditions such as temperature, which can affect the accuracy of alignment. Furthermore, the printing spacing of the printed patterns may also deviate depending on the quality of the main body component used, which will also affect the accuracy of alignment.

[0005] In Patent Document 1, processing devices such as transverse heat sealing devices and cross-cutting devices are equipped with sensors for detecting markings on the main body and pairs of drive rollers for intermittently conveying the main body. Furthermore, the drive roller pairs are controlled based on the sensor output to position the main body relative to the sensor and the processing device corresponding to the drive roller pair. This ensures that the main body is accurately aligned with each processing device.

[0006] With this intermittent conveying control, when the intermittent conveying amount of the body component differs between the drive roller pair and the next drive roller pair downstream, the tension of the body component fluctuates between these drive roller pairs, potentially exceeding the allowable upper or lower limit. This can lead to a problem where bag making cannot continue. Patent Document 1 addresses this problem by providing a tension adjusting roller (dancer roll) between these drive roller pairs and using the tension adjusting roller to temporarily store the body component. Various tension management methods are being investigated.

[0007] The raw materials for bags, such as the body and gussets, are typically laminated films, which offer high rigidity and durability. Instead, from an environmental perspective, single-material (monolithic) or composite materials, including paper substrates and resin layers coated thereon, are gaining attention as bag raw materials.

[0008] Single raw materials can be, for example, polyethylene or polypropylene. Single raw materials have higher elasticity compared to laminated films. Therefore, single raw materials are easier to align using tension; however, if the tension of the main component exceeds the allowable range, a mechanism is needed to handle this situation.

[0009] The composite raw materials used in paper-based substrates have low elasticity. Therefore, it is difficult to align such composite raw materials using tension control. Furthermore, when there is uneven printing spacing in the main body, it is difficult to control the alignment to address this unevenness.

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: Japanese Patent Application Publication No. 2008-100466

[0013] Patent Document 2: Japanese Patent Application Publication No. 2012-206458

[0014] Patent Document 3: Japanese Patent Application Publication No. 2010-105186

[0015] Patent Document 4: Japanese Patent Application Publication No. 2019-196238

[0016] Patent Document 5: Japanese Patent Application Publication No. 2015-221538 Summary of the Invention

[0017] The purpose of this application is to achieve, in a novel way, both the alignment of the body component with respect to the processing device and the management of the tension of the body component.

[0018] According to one embodiment of this application, a bag-making machine is provided, which cross-cuts at least two sheet-shaped body parts along the width direction of the body parts, and sequentially manufactures bags from the body parts, wherein at least one of the body parts includes repeatedly printed markings.

[0019] The bag-making machine includes:

[0020] An intermittent conveying device intermittently conveys the main body components along their length in an overlapping manner.

[0021] At least one first processing device processes the body component whenever the intermittent conveying is temporarily stopped;

[0022] At least one second processing device processes the body component whenever intermittent conveying is temporarily stopped; and

[0023] The adjustment device is located downstream of the first processing device and upstream of the second processing device.

[0024] The intermittent conveying device includes:

[0025] A first sensor, located upstream of the adjustment device, is used to detect the mark;

[0026] The first drive roller pair is located upstream of the adjustment device and is used to convey the body component along the length direction of the body component.

[0027] A second sensor, located further downstream than the adjustment device, is used to detect the mark; and

[0028] The second drive roller pair, located further downstream than the adjustment device, is used to convey the body component along its length.

[0029] The first drive roller pair is controlled based on the output from the first sensor to align the body component relative to the first processing device when it is temporarily stopped.

[0030] The second drive roller pair is controlled based on the output from the second sensor to align the main body relative to the second processing device when it is temporarily stopped.

[0031] The adjustment device is configured to detect an upper threshold and a lower threshold for the length of the body member contained in the interval from the first drive roller pair to the second drive roller pair.

[0032] The bag-making machine also includes:

[0033] A moving device is used to move the first processing device and the first sensor as a movable assembly along the length direction of the main body.

[0034] The moving device moves the movable group upstream in response to the adjusting device detecting the upper threshold, and moves the movable group downstream in response to the adjusting device detecting the lower threshold.

[0035] When the movable assembly is moved, the intermittent conveying device determines the intermittent conveying distance based not only on the output from the first sensor but also on the moving distance of the movable assembly, and conveys the body component at the determined intermittent conveying distance via the first drive roller pair.

[0036] The first processing device may include:

[0037] A transverse sealing device heat-seales the body component along its width whenever intermittent conveying is temporarily stopped; and

[0038] A cooling device is provided for the parts heat-sealed by the transverse sealing device, whenever intermittent transport is temporarily stopped.

[0039] The second processing apparatus may include:

[0040] A cross-cutting device cross-cuts the body component along its width direction whenever intermittent conveying is temporarily stopped.

[0041] The second processing apparatus may further include: at least one punching device for punching the body part whenever the intermittent conveying is temporarily stopped.

[0042] The at least one punching device may include

[0043] At least one of a cut-forming device for forming a cut in the bag, or a corner-cutting device for forming a corner portion of the bag.

[0044] The adjustment device may include:

[0045] Two guide rollers are arranged at intervals from each other along the length of the body and engage with the body.

[0046] A control roller is disposed between the two guide rollers and engages with the body component;

[0047] Force-applying member for applying force to the control roller against the body member; and

[0048] A position sensor is used to detect the position of the control roller corresponding to the upper threshold and the lower threshold.

[0049] In another embodiment, a bag-making method involves cross-cutting at least two sheet-like body parts along their width direction, and sequentially manufacturing bags from these body parts. At least one of the body parts contains repeatedly printed markings.

[0050] The bag-making method includes:

[0051] Using a first pair of drive rollers and a second pair of drive rollers located further downstream than the first pair of drive rollers, the body component is intermittently conveyed along the length of the body component in an overlapping manner.

[0052] The length of the body component contained in the interval is detected using an adjustment device set in the interval from the first drive roller pair to the second drive roller pair.

[0053] The body component is processed using at least one first processing device located upstream of the adjustment device whenever intermittent conveying is temporarily stopped; and

[0054] The body component is processed using at least one second processing device located further downstream than the adjustment device whenever intermittent conveying is temporarily stopped.

[0055] Intermittently transporting the main body component includes:

[0056] The mark is detected using a first sensor located upstream of the adjustment device;

[0057] Based on the output of the first sensor, the first drive roller pair is controlled to align the body component relative to the first processing device when it is temporarily stopped.

[0058] The mark is detected using a second sensor located further downstream than the adjustment device; and

[0059] Based on the output of the second sensor, the second drive roller pair is controlled to align the main body relative to the second processing device when it is temporarily stopped.

[0060] In response to the length reaching a predetermined upper threshold, a moving device is used to move the first processing device and the first sensor as a movable assembly upstream.

[0061] In response to the length reaching a predetermined lower threshold, the movable assembly is moved downstream as a whole using the moving device.

[0062] When the movable assembly is moved, the intermittent conveying distance is determined not only based on the output from the first sensor but also based on the moving distance of the movable assembly, and the intermittent conveying distance is determined by conveying the body component through the first drive roller pair.

[0063] The body component may be a membrane containing a single raw material.

[0064] The first processing device may include:

[0065] A transverse sealing device heat-seales the body component along its width whenever intermittent conveying is temporarily stopped; and

[0066] A cooling device is provided for the parts heat-sealed by the transverse sealing device, to cool them whenever intermittent conveying is temporarily stopped.

[0067] The second processing apparatus may include:

[0068] A cross-cutting device cross-cuts the body component along its width direction whenever intermittent conveying is temporarily stopped. Attached Figure Description

[0069] Figure 1A This is a schematic plan view of the upstream section of an illustrative bag-making machine. Figure 1B This is its front view.

[0070] Figure 2A This is a schematic plan view of the downstream section of an illustrative bag-making machine. Figure 2B This is its front view.

[0071] Figure 3A It is a general outline of the processed example body part. Figure 3B It is the cross-cutting Figure 3A A magnified view of the double-dotted area.

[0072] Figure 4 The illustration shows a mark that is repeatedly printed on the body part.

[0073] Figures 5A-5C An outline of the adjustment device is shown.

[0074] Figure 6 This illustrates the relationship between tension and applied force.

[0075] Explanation of symbols

[0076] 10, 11: Main body components

[0077] 32: Lateral sealing device (first processing device)

[0078] 33: Cooling device (first processing device)

[0079] 34, 35: Blanking device (second processing device)

[0080] 36: Cross-cutting device (second processing device)

[0081] 4: Intermittent conveying device

[0082] 40: First Sensor

[0083] 41: Second sensor

[0084] 42: First drive roller pair

[0085] 43: Second drive roller pair

[0086] 5: Adjustment device

[0087] 50: Guide roller

[0088] 51: Control Roller

[0089] 6: Mobile devices

[0090] M: Marker Detailed Implementation

[0091] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings.

[0092] Figure 1A , Figure 1B The upstream section of the illustrated bag-making machine is shown in schematic form. A large sheet of material 1 is continuously wound from the blank 1' at a certain speed by a pair of drive rollers 21, and cut along its length by a pressure accumulator 20, thus becoming two sheet-like body parts 10 and 11. These body parts 10 and 11 are conveyed in an up-down facing manner. The conveying direction of body parts 10 and 11 is indicated by the symbol X1. Body parts 10 and 11 are, for example, plastic films.

[0093] Body components 10 and 11 can be laminated films comprising a substrate layer and a sealant layer, or films made from a single raw material (single material) such as polyethylene (PE) or polypropylene (PP). Laminated films are strong and have low shrinkage. Single raw materials such as polyester and polyethylene are easily recyclable, environmentally friendly, have low melting points, and high shrinkage. Instead of films, body components 10 and 11 can comprise a paper substrate and a resin layer coated on the paper substrate.

[0094] Next, body components 10 and 11 pass through tension adjustment device 22. Tension adjustment device 22 appropriately converts the conveying of body components 10 and 11 from continuous conveying to intermittent conveying. Therefore, body components 10 and 11, in a section further downstream of tension adjustment device 22, pass through intermittent conveying device 4 (described later). Figure 2A , Figure 2B Intermittent transport. That is, body parts 10 and 11 are transported, temporarily stopped, and then transported again. The transport and temporary stop are repeated alternately.

[0095] Component supply device 23 ( Figure 1B The component supply device 23 is located further downstream than the tension adjustment device 22. The component supply device 23 guides the auxiliary component 12 ( Figure 1A The material is guided and supplied to the space between the main body 10 and the main body 11. The auxiliary part 12 is, for example, a continuous zipper. Hereinafter, the embodiment will be described with reference to the auxiliary part 12 being a zipper.

[0096] Body components 10 and 11 are guided towards guide roller 24 and overlap each other at the position of guide roller 24. Then, body components 10 and 11 are intermittently conveyed by intermittent conveying device 4 in an overlapping state. When body components 10 and 11 overlap each other, zipper 12 is sandwiched between body components 10 and 11.

[0097] The zipper sealing device 25 is located further downstream than the guide roller 24. Whenever the intermittent feed is temporarily stopped, the zipper sealing device 25 heat-seals the male and female parts of the zipper 12 to the body component 10 and body component 11 respectively by means of heat sealing components.

[0098] Figure 2A , Figure 2B The downstream portion of the illustrated bag-making machine is shown in a schematic diagram. The bag-making machine includes an intermittent conveying device 4. The intermittent conveying device 4 intermittently conveys sheet-shaped body parts 10 and 11 along the length of the body parts 10 and 11. The intermittent conveying device 4 will be described in detail later.

[0099] The bag-making machine also includes a longitudinal sealing device 30. The longitudinal sealing device 30 heat-seals the body parts 10 and 11 along their length direction using heat-sealing components whenever intermittent conveying is temporarily stopped. The longitudinal seal is positioned relative to the zipper 12 of the body parts 10 and 11 (at...). Figure 2A , Figure 2B (Illustration omitted) represents the distal side edge. This forms the longitudinal sealing portion 13. Figure 3A ).

[0100] The bag-making machine also includes a transverse sealing device 32 located downstream of the longitudinal sealing device 30. Multiple transverse sealing devices 32 are provided, for example, two. Whenever intermittent conveying is temporarily stopped, the transverse sealing device 32 heat-seals the body parts 10 and 11 along their width direction using a heat-sealing rod or the like. This forms a transverse sealing portion 14. Figure 3A ).

[0101] The bag-making machine also includes spot sealing devices 31. Multiple spot sealing devices 31 are provided, for example, three. Two spot sealing devices 31 are located upstream of the transverse sealing device 32, and one spot sealing device 31 is located downstream of the transverse sealing device 32. Whenever intermittent conveying is temporarily stopped, the spot sealing devices 31 locally heat and pressurize the zipper 12 using heat-sealing components, etc., to flatten it. Such a spot sealing device 31 is disclosed, for example, in Patent Document 4. The spot seal is located at the part where the transverse sealing portion 14 is formed.

[0102] The bag-making machine also includes a cooling device 33 located downstream of the transverse sealing device 32 and the point sealing device 31. Multiple cooling devices 33 are provided, for example, two. Whenever intermittent conveying is temporarily stopped, the cooling device 33 cools the portion (i.e., the transverse sealing portion 14) that is heat-sealed by the transverse sealing device 32 via cooling components or the like.

[0103] The bag-making machine also includes a punching device 34 and a punching device 35 located downstream of the cooling device 33. For example, a cut-forming device 34 and a corner-cutting device 35 are used as the punching devices. The cut-forming device 34 punches the body parts 10 and 11 with a punch cutter or the like to form holes 15 for cutting whenever intermittent conveying is temporarily stopped. Figure 3A The punching position is inside the transverse sealing part 14.

[0104] The corner-cutting device 35 punches the body parts 10 and 11 with a punch or a Thomson cutter to form the corner-cutting portion 16 whenever the intermittent feed is temporarily stopped. Figure 3A The punching positions are at both ends of the transverse sealing part 14.

[0105] The bag-making machine also includes a cross-cutting device 36 located downstream of the punching devices 34 and 35. Whenever intermittent conveying is temporarily stopped, the cross-cutting device 36 cross-cuts the body parts 10, 11, and zipper 12 along the width direction of the body parts 10 and 11 using a cutter or similar tool. The cross-cutting position is at the location of the transverse sealing portion 14. Each time a cross-cut is performed, the bag is formed from the portion removed during the cross-cutting.

[0106] Therefore, the longitudinal sealing portion 13 is positioned along one end edge of the bag. The transverse sealing portion 14 is positioned along both sides of the bag. The zipper 12 provides free opening and closing of the bag. The flattened portions of the zipper 12 are located on both sides of the bag (transverse sealing portion 14), thereby giving the bag a tight seal (see Patent Document 4, etc.). The slit 15 is divided into two parts by cross-cutting to form a slit 150 for opening the bag (see...). Figure 3B The cut corners 16 are located at the four corners of the bag, thus providing security. The sealing portions 13 and 14 leave marks inside the bag, so they may be a factor even if they affect the bag's appearance.

[0107] Although not illustrated, the body parts 10 and 11 are decorated with repeatedly printed patterns along their length at printing intervals to create a bag with printed patterns. For example... Figure 4As shown, the mark M is included in each printed pattern of the body 10 and / or body 11. That is, the mark M is repeatedly printed on at least one of the body 10 and body 11 at printing intervals. The mark M may be part of the printed pattern. The mark M may also be, for example, a contrast variation point included in each printed pattern, as disclosed in WO2020 / 026620.

[0108] In order to intermittently transport the body parts 10 and 11 with printing pitch, the intermittent transport device 4 includes a first sensor 40, a second sensor 41, a first drive roller pair 42, a second drive roller pair 43, and a control unit 44.

[0109] The first sensor 40 is positioned downstream of the transverse sealing device 32 and upstream of the cooling device 33 for detecting the mark M. An optical sensor is used as the first sensor 40.

[0110] The first sensor 40 detects the mark M on the body component 10 when it is intermittently transported and then stops at the reference position. At this time, when the mark M passes the reference position and stops, the distance traveled is measured. When the mark M is not detected, that is, when the mark M has not reached the reference position, the first sensor 40 moves upstream until the mark M is detected, and after measuring the amount of movement, it returns to the reference position.

[0111] On the main body, the dimension between the mark M and the line to be intersected (hereinafter, the intersecting line) is predetermined. The first sensor 40 is positioned such that, in the adjustment device 5 described later, with the control roller 51 at the center of its movable area, the mark M is located in the detection area (reference position) of the first sensor 40 when the intersecting position of the intersecting device 36 coincides exactly with the intersecting line.

[0112] On the main body, the dimensions between the mark M and the part to be laterally sealed (hereinafter, the lateral sealing part) are also predetermined. The point sealing device 31, the lateral sealing device 32, and the cooling device 33 are positioned such that when the first sensor 40 detects the mark M (when it is in the reference position), their machining positions (point sealing position, lateral sealing position, and cooling position) coincide with the lateral sealing part.

[0113] The first drive roller pair 42 is positioned downstream of the cooling device 33 and upstream of the punching device 34 and punching device 35. The first drive roller pair 42 can intermittently transport the body parts 10 and 11 sandwiched between it by intermittently rotating using a drive source such as a servo motor (not shown).

[0114] The second sensor 41 is positioned downstream of the first drive roller pair 42, and more specifically, downstream of the punching device 34 and punching device 35, and upstream of the cross-cutting device 36, for detecting the mark M. An optical sensor is used as the second sensor 41, and its operation is the same as that of the first sensor 40. The second sensor 41 is positioned such that the mark M is located within the detection area (reference position) of the second sensor 41 when the cross-cutting position of the cross-cutting device 36 exactly coincides with the cross-cutting line.

[0115] On the main body, the dimension between the mark M and the part to be punched (hereinafter, the punching part) is also predetermined. The punching device 34 and the punching device 35 are positioned such that when the second sensor 41 detects the mark M (when it is in the reference position), its punching position matches the punching part.

[0116] The control unit 44 includes, for example, a controller or a motor driver. Two sensors 40 and 41 and two drive roller pairs 42 and 43 are electrically connected to the control unit 44.

[0117] The control unit 44 receives an output signal from the first sensor 40 and, based on the output, controls the first drive roller pair 42 via a motor, specifically controlling the conveying speed (distance) of the body parts 10 and 11 by the first drive roller pair 42. Thus, even if the printing pitch changes or deviates for some reason, the body parts 10 and 11 are intermittently conveyed at the position of the first sensor 40 with the actual printing pitch. More specifically, when it is determined that the conveying of the body parts 10 and 11 at the position of the first sensor 40 is ahead of the design value, the control unit 44 reduces the conveying distance using the first drive roller pair 42 by the leading distance measured by the first sensor 40. On the other hand, when it is determined that the conveying of the body parts 10 and 11 at the position of the first sensor 40 is delayed compared to the design value, the control unit 44 increases the conveying distance using the first drive roller pair 42 by the delayed distance measured by the first sensor 40.

[0118] By using the control of the mark M, the first sensor 40 and the first drive roller pair 42, the control unit 44 aligns the body parts 10 and 11 (their transverse sealing portions) with the point sealing device 31 (their point sealing position), the transverse sealing device 32 (their transverse sealing position) and the cooling device 33 (their cooling position) when the body parts 10 and 11 are temporarily stopped.

[0119] The control unit 44 receives the output signal from the second sensor 41 and, based on the output, controls the second drive roller pair 43 via a motor, specifically controlling the conveying speed of the body parts 10 and 11 by the second drive roller pair 43. Thus, even if the printing pitch changes or deviates for some reason, the body parts 10 and 11 are intermittently conveyed at the position of the second sensor 41 with the actual printing pitch. More specifically, when it is determined that the conveying of the body parts 10 and 11 at the position of the second sensor 41 is ahead of the design value, the control unit 44 reduces the conveying distance using the second drive roller pair 43 by the leading distance measured by the second sensor 41. On the other hand, when it is determined that the conveying of the body parts 10 and 11 at the position of the second sensor 41 is delayed compared to the design value, the control unit 44 increases the conveying distance using the second drive roller pair 43 by the delayed distance measured by the second sensor 41.

[0120] By controlling the mark M, the second sensor 41, and the second drive roller pair 43, the control unit 44 aligns the body parts 10 and 11 (their intersecting cutting lines) relative to the intersecting cutting device (their intersecting cutting position) when the body parts 10 and 11 are temporarily stopped. Simultaneously, through this control, the body parts 10 and 11 (their punching portions) are also aligned relative to the punching device 34 and punching device 35 (their punching positions).

[0121] For example, the design positions of the point sealing device 31, the lateral sealing device 32, and the cooling device 33, when the first sensor 40 detects mark M (at the reference position), are determined as default values. In the case where the body parts 10 and 11 are made of a single raw material with a high coefficient of thermal expansion, these positions may deviate slightly due to temperature and humidity conditions. In such cases, the operator can also visually adjust their processing positions (point sealing position, lateral sealing position, cooling position).

[0122] In this embodiment, the first sensor 40 and the first drive roller pair 42 are used to align the body 10 and body 11 (printed pattern) with the dot sealing device 31 (dot sealing position), the transverse sealing device 32 (transverse sealing position), and the cooling device 33 (cooling position). Hereinafter, these devices 31-33 will be referred to as the first processing device.

[0123] Using the combination of the second sensor 41 and the second drive roller pair 43, the body parts 10 and 11 (with their printed patterns) are aligned with the cross-cutting device 36 (cross-cutting position) and the punching device 34 and punching device 35 (punching position). Hereinafter, these devices 34-36 will be referred to as the second processing device.

[0124] Since the first sensor 40 is located near the first processing device, the printed pattern can be precisely aligned with the processing position of each of the first processing devices. Similarly, since the second sensor 41 is located near the second processing device, the printed pattern can be precisely aligned with the processing position of each of the second processing devices. Therefore, the printed pattern can be precisely aligned with both the first and second processing devices. Thus, even if the printing spacing changes due to environmental conditions such as heat generated during the heat-sealing process, or the quality of the body parts 10 and 11, the bag-making machine of this embodiment can produce aesthetically pleasing bags with printed patterns.

[0125] In the intermittent conveying control, for example, if the conveying of the body parts 10 and 11 at the reference position of the first sensor 40 tends to be delayed, increasing the conveying distance using the first drive roller pair 42, while the conveying of the body parts 10 and 11 at the reference position of the second sensor 41 tends to be ahead, decreasing the conveying distance using the second drive roller pair 43, then the body parts 10 and 11 may become slack in the interval from the first drive roller pair 42 to the second drive roller pair 43. This is particularly likely to occur when the body parts 10 and 11 are made of a single raw material.

[0126] Conversely, if the conveying of the body parts 10 and 11 at the reference position of the first sensor 40 tends to lead, thus reducing the conveying distance using the first drive roller pair 42, and on the other hand, the conveying of the body parts 10 and 11 at the reference position of the second sensor 41 tends to be delayed, thus increasing the conveying distance using the second drive roller 43, then the body parts 10 and 11 may exceed the permissible range within the said interval.

[0127] Furthermore, there are cases where the tension of body component 10 and body component 11 differs with the drive roller pair as the boundary, making tension management within the aforementioned range important. Therefore, the bag-making machine includes the following structure.

[0128] The bag making machine includes an adjustment device 5 ( Figure 2A , Figure 2B The adjustment device 5 is located downstream of the first sensor 40 and the first drive roller pair 42 and upstream of the second sensor 41 and the second drive roller pair 43, and adjusts the tension. Regarding the adjustment device 5, in... Figure 5ADetails are shown below. The adjustment device 5 includes: two guide rollers 50, spaced apart from each other along the length of the body members 10 and 11 and configured to be immovable, engaging with the body members 10 and 11; and a control roller 51, disposed between the guide rollers 50 and engaging with the body members 10 and 11. Although not shown, the adjustment device 5 also includes a force-applying member that supports the control roller 51, is movable in the vertical direction, and applies a downward force to the body members 10 and 11.

[0129] like Figure 6 As shown, the winding angle of the main body 10 and main body 11 toward the control roller 51 is set to 2θ, the applied force including the weight of the control roller 51 is set to F, and the tension of the main body 10 and main body 11 is set to T. If the small forces such as friction in the direction of roller rotation are ignored, the following formula is actually true.

[0130] F=2Tsinθ

[0131] Therefore, by controlling the applied force F to be small when the position of the control roller 51 is high (θ is small) and controlling the applied force to be large when the position of the control roller 51 is low (θ is large), the tension of the body 10 and body 11 can be maintained within a certain range.

[0132] By controlling the applied force of the force-applying components in this way, the tension of the body components 10 and 11 in the interval between the drive roller pair 42 and the drive roller pair 43 can be managed.

[0133] The adjustment device 5 is further configured to detect an upper threshold and a lower threshold for the length (hereinafter referred to as "body member interval length") of the body members 10 and 11 contained in the interval from the first drive roller pair 42 to the second drive roller pair 43. Although not shown, the adjustment device 5 also includes a position sensor for detecting the position of the control roller 51 corresponding to these thresholds.

[0134] For example, when the length of the body section becomes shorter, the control roller 51 is located at a higher position. Figure 5B When the length of the body component section increases, the control roller 51 is located at a lower position. Figure 5C Thus, the length of the body section corresponds to the vertical position of the control roller 51. Therefore, the adjustment device 5 uses a position sensor to position the control roller 51 at its upper limit position (see reference). Figure 5B (dashed line) / lower limit position (reference) Figure 5C (Dashed line) is used for detection, which can detect when the length of the body component interval reaches the lower threshold / upper threshold.

[0135] The bag-making machine further includes a moving device 6 ( Figure 2A , Figure 2B The moving device 6 is used to enable the first processing device 31, the first processing device 32, the first processing device 33, and the first sensor 40 to move a small distance relative to other devices of the bag making machine in the length direction of the main body 10 and the main body 11, i.e. upstream and downstream.

[0136] Regarding the moving device 6, although details are omitted, it includes, for example, a frame equipped with a movable assembly, a rack and pinion mechanism for moving the frame, and a drive source such as a motor for operating the rack and pinion mechanism. Alternatively, the moving device 6 may also include known structures such as a structure with a track and driven by a worm gear. Furthermore, the moving device 6 operates based on the output of the position sensor of the adjusting device 5 as follows.

[0137] When the adjustment device 5 detects that the length of the body section reaches the lower threshold, i.e., the control roller 51 is at the upper limit position, by using the intermittent conveying control of the control unit 44, the moving device 6 responds by moving the movable group downstream by a small distance, and then changes the intermittent conveying distance using the first drive roller pair 42, thereby causing the control roller 51 to descend.

[0138] For example, a more detailed explanation will be given regarding the case where the intermittent conveying interval, which serves as a reference, is set in 100mm increments, and the movement of the movable assembly is set in 2mm increments.

[0139] When the adjusting device 5 detects that the control roller 51 is at the upper limit position when the conveying of the main body 10 and the main body 11 stops, the intermittent conveying device 4 and the moving device 6 operate as follows.

[0140] The intermittent conveying device 4 uses the first sensor 40 to detect the mark M and calculates a conveying delay of 0.5 mm based on its output. Furthermore, after detection, sealing processing, and cooling using the first sensor 40, the moving device 6 moves the movable assembly 2 mm downstream.

[0141] Based on the output obtained from the first sensor 40 and the moving distance of the movable assembly, the intermittent conveying device 4 determines the next intermittent conveying distance using the first drive roller pair 42 to be 102.5 mm (100 mm + 0.5 mm + 2 mm). Furthermore, in the next intermittent conveying cycle, the intermittent conveying device 4 conveys the body parts 10 and 11 by 102.5 mm (the determined intermittent conveying distance) using the first drive roller pair 42. Here, +0.5 mm is a correction amount determined by the output of the first sensor 40, and +2 mm is a correction amount determined based on the movement of the movable assembly, equal to the moving distance of the movable assembly.

[0142] By performing the aforementioned control, taking the position of the first sensor 40 as a reference, the main body components 10 and 11 are only moved by 100.5 mm, and the positions of the point sealing device 31, the transverse sealing device 32, and the cooling device 33 relative to the mark M can be accurately determined. Furthermore, by using the first drive roller pair 42 to additionally move the main body components 10 and 11 downstream of the movable assembly by an additional amount (2 mm), the length of the main body component interval will not fall below the lower threshold.

[0143] On the other hand, when the adjustment device 5 detects that the length of the body section reaches the upper threshold, i.e., the control roller 51 is at the lower limit position, by using the intermittent conveying control of the control unit 44, the moving device 6 responds to this by moving the movable group upstream a small distance, thereby changing the intermittent conveying distance using the first drive roller pair 42, thereby causing the control roller 51 to rise.

[0144] When the adjusting device 5 detects that the control roller 51 is at the lower limit position when the conveying of the main body 10 and the main body 11 stops, the intermittent conveying device 4 and the moving device 6 operate as follows.

[0145] The intermittent conveying device 4 uses the first sensor 40 to detect the mark M and calculates, for example, a conveying delay of 0.5 mm based on its output. Furthermore, after detection, sealing processing, and cooling using the first sensor 40, the moving device 6 moves the movable assembly 2 mm upstream.

[0146] Based on the output obtained from the first sensor 40 and the moving distance of the movable assembly, the intermittent conveying device 4 determines the next intermittent conveying distance using the first drive roller pair 42 to be 98.5 mm (100 mm + 0.5 mm - 2 mm). Furthermore, in the next intermittent conveying cycle, the intermittent conveying device 4 conveys the body parts 10 and 11 by 98.5 mm (the determined intermittent conveying distance) using the first drive roller pair 42. Here, +0.5 mm is a correction amount determined by the output of the first sensor 40, and -2 mm is a correction amount determined based on the movement of the movable assembly, equal to the moving distance of the movable assembly.

[0147] As a result, the positions of the point sealing device 31, the transverse sealing device 32, and the cooling device 33 relative to the mark M can be accurately determined. Furthermore, by using the first drive roller pair 42 to move the body parts 10 and 11 to the upstream side of the movable assembly by a small amount of movement (2 mm), the interval length of the body parts 10 and 11 will not exceed the upper threshold.

[0148] As described above, when the movable assembly is moved, its movement distance is taken into account as a correction amount for the intermittent conveying distance using the first drive roller pair 42. Therefore, the length of the body section will not exceed the range from the lower threshold to the upper threshold and will be managed to an appropriate value, and the tension of the body parts 10 and 11 can also be managed within a certain range.

[0149] Furthermore, the mechanically movable range of the control roller 51 is wider than the upper / lower limit position, and the force applied to the control roller 51 can also be appropriately set according to the material or width of the body component.

[0150] The bag-making machine continuously measures the moving distance of the movable assembly and continuously calculates the distance from the cross-cutting position to the reference position of the first sensor 40. That is, the bag-making machine can continuously calculate the reference position of the first sensor 40, which changes according to the condition of the body parts 10 and 11, which expand and contract even due to environmental changes such as temperature or humidity.

[0151] The moving distance and timing of the movable group can be appropriately set. For example, the movable group can be moved in 3mm or 5mm increments. When the length of the body section between the main body 10 and the main body 11 varies greatly, it can be moved by 2 or 3 increments.

[0152] This structure enables high-precision alignment of each group in the processing unit controlled by a single sensor, and also allows for proper tension management from the start of the first drive roller pair to the next. Therefore, stable bag making can be achieved even when using printed packaging materials with high elongation.

[0153] In particular, the films constituting the body parts 10 and 11 are very easy to stretch due to the heat generated by the heat sealing process, so the intermittent transport control in embodiments following the heat sealing process is extremely effective.

[0154] Furthermore, if a processing device requiring high-precision alignment is added in addition to the devices 31-36 of the embodiments, the intermittent transport control and tension management described above can be performed simply by placing the additional set of sensors and drive roller pairs near the processing device and providing a moving device that moves the sensors, drive roller pairs, and the processing device as a whole in the upstream and downstream directions. This allows for high-precision alignment of the body components 10 and 11 to the processing position of the processing device and appropriate tension management.

[0155] Generally, to allow the operator to visually confirm the lateral sealing position or point sealing position, a certain amount of space is ensured between the lateral sealing device 32 / point sealing device 31 and the cooling device 33. The first sensor 40 and its movable unit are configured to effectively utilize the idle space of the bag-making machine.

[0156] Alternatively, two sheet-like body parts 10 and 11 can be formed by folding the sheet 1 along its length without cutting it. In this case, the two sheet-like body parts 10 and 11 are connected to each other via a bending line. In this type of bag making, the longitudinal sealing device 30 is omitted.

[0157] In addition to the zipper 12, the component supply device 23 can supply other auxiliary components such as corner braces (bottom corner braces, top corner braces, side corner braces) to the body parts 10 and 11, and / or, instead of the zipper 12, can supply other auxiliary components such as corner braces (bottom corner braces, top corner braces, side corner braces) to the body parts 10 and 11. Furthermore, in addition to the body parts 10 and 11, the corner braces can also be formed from the sheet material 1. The longitudinal sealing device 30 or the transverse sealing device 32 can also heat-seal them while the corner braces are spaced between the body parts 10 and 11. Those skilled in the art will readily understand that the intermittent conveying control can also be applied to various bag-making methods other than those described in the embodiments.

[0158] Single-material films are easier to stretch, have a lower melting point, and are more difficult to manage in terms of sealing temperature and conveying speed compared to laminated films. Furthermore, single-material films exhibit greater quality variations. Therefore, single-material films are more difficult to align during bag making compared to laminated films. In this embodiment, as described above, high-precision alignment can be provided even when the body parts 10 and 11 are elongated, making it particularly effective for bag making using single-material films. In the flexible packaging industry, bag making using single-material films is being re-evaluated from a recycling perspective, making the bag making method described in this embodiment highly effective.

[0159] The melting point of a single-material membrane is generally lower than that of a laminated membrane. Therefore, when using a single-material membrane, the two upstream point sealing devices 31 can be heated at a lower temperature than that used in laminated membranes, suppressing damage to the body parts 10 and 11. Furthermore, by further pressurizing and heating the flattened portion using the two transverse sealing devices 32, the thickness of the flattened portion of the zipper 12 can be further reduced while suppressing damage to the body parts 10 and 11. Additionally, the downstream point sealing device 31 can further pressurize the flattened portion, which has softened through heating and pressurization. Thus, a leak-free seal can be reliably achieved.

[0160] When a film made from a single raw material is used as the body parts 10 and 11, its high elasticity allows the adjustment device 5 to be omitted from the bag-making machine. Alignment is performed by the first sensor 40 at the position of the first drive roller pair 42 and by the second sensor 42 at the position of the second drive roller pair 43. Therefore, the number of spacings of the body parts 10 and 11 within the interval from the first drive roller pair 42 to the second drive roller pair 43 remains unchanged. Therefore, a certain degree of tension can be applied to the body parts 10 and 11 in the initial state. Even if the body parts 10 and 11 expand or contract, the number of spacings within the interval remains unchanged, and the cutting positions of the cutting devices 34 and 35 will not deviate relative to the body parts 10 and 11.

[0161] That is, if the actual printing pitch is shorter than the initial printing pitch due to its unevenness or due to the shrinkage of the body parts 10 and 11, the body parts 10 and 11 will elongate in the interval and the tension will increase, but the printing position will not deviate from the punching position. Conversely, if the actual printing pitch is longer than the initial printing pitch due to its unevenness or due to the elongation of the body parts 10 and 11, the tension applied to the body parts 10 and 11 in the interval will be eased and lower than the initial value, and the printing position will not deviate from the punching position.

[0162] Considering the physical properties of body parts 10 and 11, the initial tension is determined to be such that even if body parts 10 and 11 extend or contract, the tension can be relieved by tension adjustment. It is assumed that when body parts 10 and 11 are over-stretched and relaxed, or over-contracted and over-tightened, this situation can be addressed by the movement of the movable assembly.

[0163] Thus, when the tension variation of body parts 10 and 11 is increased for alignment, the alignment accuracy becomes higher relative to uneven printing. On the other hand, the tension deviation during sealing becomes larger. As a result, the quality of the sealing process tends to be unstable.

[0164] On the other hand, when the adjustment device 5 is used to reduce the tension variation, the tension deviation during sealing decreases. As a result, the quality of the sealing process is stable. However, when uneven printing occurs, there is a limit to the adjustment range under tension. In this case, adjustment can be made by moving the movable assembly.

[0165] The body of the paper substrate has almost no expansion or contraction compared to the body of the resin substrate. Therefore, it is difficult to address the situation using tension control when there is uneven printing spacing in the body of the paper substrate. In the case of the bag-making machine illustrated in the attached figure, the positions of the dot sealing device 31, the transverse sealing device 32, and the cooling device 33 relative to the mark M can be accurately determined by the movement of the movable assembly, without relying on tension control.

Claims

1. A bag making machine characterized by, at least two body pieces in the form of a web are cross-cut in the width direction of the body pieces, and bags are sequentially manufactured from the body pieces, at least either of the body pieces including a repeatedly printed mark, the bag making machine includes: an intermittent conveying device that intermittently conveys the body pieces in the length direction of the body pieces in a state of being overlapped with each other; at least one first processing device that processes the body pieces every time the intermittent conveying is temporarily stopped; at least one second processing device that processes the body pieces every time the intermittent conveying is temporarily stopped; and an adjustment device that is provided at a position more downstream than the first processing device and more upstream than the second processing device, the intermittent conveying device includes: a first sensor that is provided at a position more upstream than the adjustment device and detects the mark; a first drive roller pair that is provided at a position more upstream than the adjustment device and conveys the body pieces in the length direction of the body pieces; a second sensor that is provided at a position more downstream than the adjustment device and detects the mark; and a second drive roller pair that is provided at a position more downstream than the adjustment device and conveys the body pieces in the length direction of the body pieces, the first drive roller pair is controlled based on an output from the first sensor to align the body pieces with respect to the first processing device at the time of temporary stop, the second drive roller pair is controlled based on an output from the second sensor to align the body pieces with respect to the second processing device at the time of temporary stop, the adjustment device is configured to detect an upper threshold value and a lower threshold value of the length of the body pieces included in an interval from the first drive roller pair to the second drive roller pair, the bag making machine further includes: a moving device that moves the first processing device and the first sensor as a movable group in the length direction of the body pieces as a unit, the moving device moves the movable group upstream in response to the adjustment device detecting the upper threshold value and moves the movable group downstream in response to the adjustment device detecting the lower threshold value, in a case where the movable group is moved, the intermittent conveying device determines an intermittent conveying distance based not only on an output from the first sensor but also on a moving distance of the movable group, and conveys the body pieces by the first drive roller pair by the determined intermittent conveying distance.

2. The bag making machine according to claim 1, wherein the first processing device includes: a transverse sealing device that heat-seals the body pieces in the width direction of the body pieces every time the intermittent conveying is temporarily stopped; and a cooling device that cools a portion heat-sealed by the transverse sealing device every time the intermittent conveying is temporarily stopped.

3. The bag making machine according to claim 1, wherein the second processing device includes: a cross-cutting device that cross-cuts the body pieces in the width direction of the body pieces every time the intermittent conveying is temporarily stopped.

4. The bag making machine according to claim 3, wherein The second processing device further includes at least one punching device that punches the body piece when intermittent conveyance is temporarily stopped.

5. The bag making machine according to claim 4, wherein The at least one punching device includes: at least either a cut forming device for forming a cut of the bag or a corner cutting device for forming a corner portion of the bag.

6. The bag making machine according to any one of claims 1 to 5, wherein The adjustment device includes: two guide rollers arranged at intervals from each other in the length direction of the body piece and engaged with the body piece; a control roller arranged between the two guide rollers and engaged with the body piece; a force applying member for applying a force to the control roller toward the body piece; and a position sensor for detecting a position of the control roller corresponding to the upper threshold value and the lower threshold value.

7. A method of making a bag, characterized by, At least two body pieces in the form of a sheet are cross-cut in the width direction of the body piece, and bags are sequentially manufactured from the body pieces, at least either of the body pieces including a repeatedly printed mark, The bag making method includes: intermittently conveying the body piece in the length direction of the body piece in a state of overlapping each other using a first drive roller pair and a second drive roller pair provided downstream of the first drive roller pair; detecting a length of the body piece included in an interval from the first drive roller pair to the second drive roller pair using an adjustment device provided in the interval; processing the body piece when intermittent conveyance is temporarily stopped using at least one first processing device provided upstream of the adjustment device; and processing the body piece when intermittent conveyance is temporarily stopped using at least one second processing device provided downstream of the adjustment device, The intermittent conveyance of the body piece includes: detecting the mark using a first sensor provided upstream of the adjustment device; controlling the first drive roller pair based on an output of the first sensor to align the body piece with respect to the first processing device when temporarily stopped; detecting the mark using a second sensor provided downstream of the adjustment device; and controlling the second drive roller pair based on an output of the second sensor to align the body piece with respect to the second processing device when temporarily stopped, in response to the length reaching a prescribed upper threshold value, moving the first processing device and the first sensor integrally as a movable group upstream using a moving device, in response to the length reaching a prescribed lower threshold value, moving the movable group integrally downstream using the moving device, when the movable group is moved, determining an intermittent conveyance distance based not only on an output from the first sensor but also on a moving distance of the movable group, and conveying the body piece by the first drive roller pair by the determined intermittent conveyance distance.

8. The bag making method according to claim 7, wherein The body piece is a film including a single raw material.

9. The bag manufacturing method according to claim 7 or 8, characterized in that, the first processing device includes: a transverse sealing device that heat-seals the body piece in the width direction of the body piece each time the intermittent conveyance is temporarily stopped; and a cooling device that cools the portion heat-sealed by the transverse sealing device each time the intermittent conveyance is temporarily stopped, the second processing device includes: a cross-cutting device that cross-cuts the body piece in the width direction of the body piece each time the intermittent conveyance is temporarily stopped.

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