Bag making machine and bag making method

Abstract

To correct deviation between two barrel materials so that one of the barrel material will not get too much load.SOLUTION: In a bag making machine, based on outputs from a sensor for detection of a mark of a first barrel material and a sensor for detection of a mark of a second barrel material, the first barrel material is corrected in the width direction on the basis of the second barrel material. Also, in the bag making machine, based on these sensor outputs, the second barrel material is corrected in the route direction on the basis of the first barrel material. In the bag making machine, the correction in the width direction is run by twisting a feed path of the first barrel material in a part section. In the bag making machine, the correction in the route direction is run by changing the length of the feed path of the second barrel material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present application relates to a bag making machine and a bag making method for producing bags from at least two web-like body materials, and in particular to correcting relative misalignment between the body materials in the width direction and length direction. [Background technology]

[0002] The bag making machine and bag making method typically involves feeding two web-like body materials in their longitudinal direction, overlapping the body materials while they are being fed, subjecting the body materials to processing such as heat sealing, and then cross-cutting the body materials in the width direction to produce bags.

[0003] When two pieces of body material have patterns applied to them by printing or other means, it is important to align them so that the patterns match each other. There are two types of alignment: alignment in the path direction (longitudinal direction of the body material) along the feed path of the body material, and alignment in the width direction (width direction of the body material) perpendicular to the path direction. To ensure accurate alignment, any misalignment between the body materials in the width direction and / or path direction is corrected.

[0004] Patent Document 1 discloses that deviations between body materials in the path direction and width direction are corrected based on detection of marks attached to the body materials by a sensor such as a camera.

[0005] Specifically, the bag-making machine in Patent Document 1 includes selvedge rolls located upstream of the position where the upper and lower body members are overlapped, and the upper body member engages with the selvedge rolls. The bag-making machine then determines the relative widthwise misalignment between the two body members based on mark detection and tilts the selvedge rolls from a horizontal position by an amount corresponding to the determined misalignment. This causes the upper body member to move relative to the lower body member, correcting the relative widthwise misalignment.

[0006] The bag making machine of Patent Document 1 further includes a print alignment roll located upstream of the position where the upper and lower body members are overlapped, and the upper body member engages with the print alignment roll. The bag making machine then determines the relative misalignment between the two body members in the path direction based on the mark detection and linearly moves the print alignment roll by an amount corresponding to the determined misalignment. This causes the bag making machine to change the feed path length of the upper body member, moving the upper body member relative to the lower body member and correcting the relative misalignment in the path direction. In this way, the bag making machine of Patent Document 1 corrects the relative misalignment in two directions by moving the upper body member relative to the lower body member.

[0007] In particular, with regard to correcting misalignment in the width direction, the bag making machine of Patent Document 1 forcibly tilts the edge-matching rolls to generate large and small (uneven) tensions in the width direction of the upper body material, causing the upper body material to slide over the edge-matching rolls, which places a large load on the upper body material.

[0008] As described above, in the bag making machine of Patent Document 1, when correcting misalignment, a large load may be applied to only one of the body materials (the upper body material). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-100467 Summary of the Invention

[0010] The present application provides a bag making machine for producing bags from at least a web-like first body material and a web-like second body material, The bag making machine comprises: a feeding device that feeds the first and second body materials in their longitudinal directions; a stacking member for stacking the first and second body materials together; a first correction member provided upstream of the overlapping member to engage with the first body material but not to engage with the second body material; and a first actuator for moving the first correction member, the first correction member moving the first correction member to twist the feed path of the first body material in a section including the first correction member; a second correction mechanism including a second correction member disposed upstream of the overlapping member so as to engage with the second body material but not engage with the first body material, and a second actuator for moving the second correction member, and which moves the second correction member to vary the feed path length of the second body material; a first sensor for detecting marks repeatedly applied to the first body material; a second sensor for detecting marks repeatedly applied to the second body material; a controller for controlling the first and second actuators; The controller activating the first actuator based on outputs from the first and second sensors to correct a widthwise deviation of the first body relative to the second body perpendicular to the feed path; The second actuator is configured to operate based on the outputs from the first and second sensors to correct a deviation of the second body member in a path direction relative to the first body member.

[0011] The first correction mechanism may be configured to include two meandering correction rollers arranged parallel to each other as the first correction member, and to rotate the two meandering correction rollers in the same plane by the first actuator.

[0012] The second correction mechanism may include a pitch correction roller as the second correction member, and may be configured to use the second actuator to linearly move the pitch correction roller in a direction perpendicular to the axis of the pitch correction roller.

[0013] The controller determining a relative displacement of the first body material relative to the second body material in the width direction based on the outputs from the first and second sensors, generating a first control signal indicating an actuation amount of the first actuator based on the relative displacement in the width direction, and transmitting the first control signal to the first actuator; The system may be configured to determine the relative deviation of the second body material in the path direction relative to the first body material based on the outputs from the first and second sensors, generate a second control signal indicating the amount of operation of the second actuator based on the relative deviation in the path direction, and transmit the second control signal to the second actuator.

[0014] The feeding device is configured to intermittently feed the first and second body materials, The first and second sensors may be positioned to detect the marks on the first and second body materials, respectively, each time there is a pause in the intermittent feeding.

[0015] The controller The apparatus may be configured to calculate the relative deviation amount in the width direction / path direction each time intermittent feeding is temporarily stopped, and to generate the first control signal / second control signal to be used in the next intermittent feeding based on the relative deviation amount.

[0016] The controller The first control signal / the second control signal may be generated based on an average value of the relative deviation amount in the width direction / the path direction determined over a plurality of intermittent feeds.

[0017] The controller The pitch amount of intermittent feeding by the feeding device may be adjusted based on the output from either the first sensor or the second sensor.

[0018] The controller determining an amount of deviation of the mark from a predetermined reference position when the intermittent feed is temporarily stopped based on the output from either the first sensor or the second sensor; calculating the pitch amount based on the calculated deviation amount; The feed device may be controlled to feed the first and second body materials at the indexed pitch amount.

[0019] The controller The pitch amount may be adjusted based on the output from the first sensor.

[0020] The bag making machine further comprises: a processing device that processes the first body material and / or the second body material; an additional sensor provided downstream of the first and second sensors and upstream of the processing device for detecting the mark on the first body material; The controller The feeder may be configured to adjust the pitch amount of intermittent feeding by the feeder based on the output from the additional sensor.

[0021] The present application also provides a bag manufacturing method for manufacturing a bag from at least a web-shaped first body material and a web-shaped second body material, The bag making method includes: feeding the first and second body materials in their longitudinal directions by a feeding device; overlapping the first and second body members with an overlapping member; a controller determining a relative deviation amount of the first body material relative to the second body material in a width direction perpendicular to the path direction based on outputs from the first sensor and the second sensor; The controller determines a relative deviation of the second body material relative to the first body material in the path direction based on the outputs from the first and second sensors, The first sensor is configured to detect marks repeatedly applied to the first body material, The second sensor is configured to detect marks repeatedly applied to the second body material, The bag making method further comprises: The controller operates a first actuator based on the amount of deviation in the width direction to move a first correction member, thereby twisting the feed path of the first body material in a section including the first correction member, and correcting the first body material in the width direction based on the second body material; and the controller operates a second actuator based on the deviation amount in the path direction to move a second correction member, and varies the feed path length of the second body material, thereby correcting the second body material in the path direction based on the first body material; The first correction member is arranged to engage with the first body material but not to engage with the second body material upstream of the overlapping member, The second correction member is disposed upstream of the overlapping member so as to engage with the second body material but not to engage with the first body material. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 shows a schematic diagram of an exemplary bag making machine. [Figure 2] 2A and 2B are views taken along line k in FIG. 1, each showing an exemplary first correcting mechanism, and FIG. 2C is an enlarged view of region T in FIG. 2B. [Figure 3] FIG. 3 is a schematic diagram illustrating an exemplary first correction mechanism. [Figure 4] FIG. 4 is a schematic diagram illustrating an exemplary second correction mechanism. [Figure 5] 5A and 5B show examples of marks applied to the body material. [Figure 6] FIG. 6 is an exemplary block diagram of a bag making machine for misalignment correction. [Figure 7] 7A and 7B are diagrams for explaining the correction of relative deviation in the width direction and the path direction, respectively. [Figure 8]FIG. 8 illustrates an example of information displayed on the screen of the display device. [Figure 9] FIG. 9 shows a schematic diagram of an exemplary movement mechanism for moving the sensor. [Figure 10] FIG. 10 is a diagram illustrating an example in which the mark (a part of the print pattern to be detected) is misaligned between the body materials. [Figure 11] FIG. 11 shows a schematic diagram of another exemplary bag making machine. DETAILED DESCRIPTION OF THE INVENTION

[0023] Embodiments of the present application will now be described with reference to the drawings, which are merely exemplary of the present application. The drawings are schematic only and may not be drawn to scale. It should also be understood that the same reference numerals are used throughout the figures to represent the same or similar components.

[0024] FIG. 1 shows a schematic diagram of an exemplary bag making machine. Two raw rolls 10', 11' are arranged at the most upstream position of the bag making machine. The raw rolls 10', 11' are formed by winding web-like (continuous) body materials 10, 11 into rolls, respectively. The body materials 10, 11 may be, for example, plastic films. The films may be single-layer films (mono-material films) or multi-layer films (composite material films). The body materials 10, 11 may also be composed of a paper base and a resin applied partially or entirely to the base. Note that single-layer films (mono-material films) are easily recyclable and are being reconsidered from the perspective of the SDGs, such as environmental protection.

[0025] The bag making machine includes a feed device 20. The feed device 20 includes at least one pair of drive rollers 200, 201 and is configured to intermittently feed the body materials 10, 11 in their longitudinal directions. The feed direction is indicated by the symbol +X. The body materials 10, 11 may be fed by only the pair of drive rollers 201. Furthermore, taking into consideration the stretchability of the body materials 10, 11, one or more pairs of drive rollers 200 may be added.

[0026] The bag-making machine further includes two dancer rollers 21 and a pair of overlapping rollers 22 as overlapping members. The bag-making machine produces the body materials 10, 11 from the respective raw rolls 10', 11' and continuously feeds them while they are separated from each other vertically, passing them through the dancer rollers 21 and then through the pair of overlapping rollers 22. As is well known, the dancer rollers 21 are operated by an appropriate actuator (not shown) to convert the feeding of the body materials 10, 11 from continuous feeding to intermittent feeding. As the body materials 10, 11 pass through the pair of overlapping rollers 22, they are overlapped with each other at the position of the pair of overlapping rollers 22 by the pair of overlapping rollers 22. Therefore, the body materials 10, 11 are intermittently fed in the section downstream of the dancer rollers 21, that is, feeding and pausing are repeated.

[0027] The bag making machine further includes at least one processing device 23 that is provided downstream of the pair of overlapping rollers 22 and processes the body materials 10, 11. The processing device 23 is, for example, a heat sealing device. The heat sealing device uses, for example, a heat sealing bar to heat seal the body materials 10, 11 in the width direction and length direction each time the bag is fed intermittently, so that the bag 1 produced has sealed portions along the periphery (three sides).

[0028] The bag making machine further includes a cross-cutting device 24 provided downstream of the processing device 23. The cross-cutting device 24 uses, for example, a cutter to cross-cut the body materials 10, 11 in their width direction at each intermittent feed, thereby sequentially producing bags 1. Bags 1 are produced from the portions cut off by the cross-cutting. Therefore, bag 1 includes at least two body materials that are sheets facing each other.

[0029] 1, as disclosed in Patent Document 1, a bag making machine may slit a web cut out from a single large-width raw roll in its longitudinal direction to form body materials 10, 11. Furthermore, the bag making machine may manufacture bag 1 by incorporating accessory members such as a bottom gusset, side gusset materials, and a zipper in addition to body materials 10, 11.

[0030] The bag making machine further includes a first correction mechanism 3, a second correction mechanism 4, and two sensors 5 and 6.

[0031] The first correction mechanism 3 comprises two meandering correction rollers 30a, 30b arranged parallel to each other at a distance from each other in the feed direction of the body material 10, upstream of the overlapping roller pair 22, and a plate-shaped support 31 that rotatably supports these rollers 30a, 30b.

[0032] The meandering correction rollers 30a and 30b are both arranged to engage with the body material 10 but not to engage with the body material 11. The meandering correction roller 30a is an upstream roller, and the meandering correction roller 30b is a downstream roller.

[0033] Figure 2A is a view taken along line k in Figure 1. As shown in Figure 2A, support 31 is attached to a fixed frame (not shown) of the bag making machine so as to be rotatable about axis AX. Axis AX is set in the center, near upstream meandering correction roller 30a.

[0034] The first correction mechanism 3 includes a first actuator 32 for rotating the meandering correction rollers 30a, 30b integrally within a small angular range around the axis AX in the same plane. The first actuator 32 is fixed to a fixed frame and connected to a support 31. When the first actuator 32 is actuated, the meandering correction rollers 30a, 30b and the support 31 rotate within the plane of the plate-shaped support 31. The rotation directions are indicated by the symbols +R and -R.

[0035] For example, the first actuator 32 is a known feed screw mechanism consisting of a feed screw (such as a trapezoidal screw) including a screw shaft and a nut, and a motor (such as a servo motor, stepping motor, or induction motor) for rotating the screw shaft to move the nut along the screw shaft. The screw shaft is fixed to a fixed frame, and the nut, which is the movable part, is directly or indirectly attached to the support 31. The amount of rotation of the correction rollers 30a, 30b (support 31) can be controlled by controlling the rotation of the screw shaft via the motor.

[0036] 2B, another exemplary first correction mechanism 3 includes a plurality of first actuators 32, which are arranged on an imaginary circle centered on an axis AX, fixed to a fixed frame, and connected to a support 31. Each of the first actuators 32 is a linear actuator and oriented so as to operate over a small distance in a tangential direction of the imaginary circle (see FIG. 2C). The first correction mechanism 3 may rotate the meandering correction rollers 30a, 30b and the support 31 integrally by simultaneously operating the plurality of first actuators 32.

[0037] The operating principle of the first correction mechanism 3 will be explained with reference to Figures 2A, 2B, and 3. In Figure 3, reference numeral 33a denotes an upstream guide roller, and reference numeral 33b denotes a downstream guide roller. The first correction mechanism 3 rotates the support 31 in the +R direction using the first actuator 32, thereby correcting the body material 10 in the +Y direction near the downstream meandering correction roller 30b. The first correction mechanism 3 also rotates the support 31 in the -R direction using the first actuator 32, thereby correcting the body material 10 in the -Y direction near the meandering correction roller 30b. The +Y and -Y directions are defined based on the planar view of the bag making machine and the feed direction +X (the same applies below). The +Y and -Y directions are width directions perpendicular to the feed path of the body material 10.

[0038] That is, the first correction mechanism 3 causes a slight twist in the feed path of the body material 10 in a section including the rollers 30a, 30b (a section upstream of the overlapping roller pair 22) by rotating the rollers 30a, 30b in this way. As a result, the first correction mechanism 3 slightly twists the body material 10 being conveyed in this section, and moves the position of the body material 10 (the position of its edge) in the width direction relative to the body material 11 to correct the trajectory.

[0039] 3, when the meandering correction rollers 30a, 30b (supports 31) are in the neutral position, it is desirable that the body material 10 be flat in the first section between rollers 33a and 30a, the second section between rollers 30a and 30b, and the third section between rollers 30b and 33b. When the meandering correction rollers 30a, 30b (supports 31) rotate, a twist occurs in the feed path in a portion of the first to third sections, resulting in the body material 10 being twisted and no longer being flat in the first and third sections. However, because the amount of rotation (and therefore the amount of twist) required for the following misalignment correction is minute, the tension distribution in the width direction of the body material 10 is approximately uniform, and the load on the body material 10 is not excessive.

[0040] Although it depends on the specific configuration of the first correction mechanism 3, as an example, if the first correction mechanism 3 is configured to be able to rotate the meandering correction rollers 30a, 30b (support 31) at an angle of about 0.5°, this is sufficient to correct the misalignment in the width direction.

[0041] 1, the second correction mechanism 4 includes a pitch correction roller 40 as a second correction member. The pitch correction roller 40 is positioned upstream of the overlapping roller pair 22 so as to engage with the body material 11 but not to engage with the body material 10.

[0042] The operating principle of the second correction mechanism 4 is explained with reference to Figure 4. The second correction mechanism 4 is equipped with a second actuator 41 used to control the position of the body material 11 in the conveying direction. The second actuator 41 is connected to a pitch correction roller 40. Operation of the second actuator 41 causes the pitch correction roller 40 to move linearly in a direction perpendicular to its axis. Note that reference numeral 42a in Figure 4 denotes an upstream guide roller, and reference numeral 42b in Figure 4 denotes a downstream guide roller.

[0043] For example, the second actuator 41 may be a known feed screw mechanism consisting of a feed screw (including a screw shaft and a nut) and a motor, similar to the first actuator 32. The feed screw mechanism is configured so that when the screw shaft is rotated by the motor, the nut and the correction pitch roller 40 attached thereto move linearly in the axial direction of the screw shaft. The amount of movement of the pitch correction roller 40 can be controlled by controlling the rotation of the screw shaft via the motor.

[0044] When the second correction mechanism 4 moves the pitch correction roller 40 closer to the guide rollers 42a and 42b using the second actuator 41, the length of the feed path for the body material 11 becomes shorter. On the other hand, when the second correction mechanism 4 moves the pitch correction roller 40 away from the guide rollers 42a and 42b using the second actuator 41, the length of the feed path for the body material 11 becomes longer.

[0045] In this way, the second correction mechanism 4 varies the feed path length of the body material 11 by moving the pitch correction roller 40. Therefore, the second correction mechanism 4 is configured to correct the body material 11 by moving it in the path direction (direction +X and direction −X ( FIG. 5A , etc.)) relative to the body material 10. This principle itself is the same as that in Patent Document 1.

[0046] As shown in Figure 1, sensors 5 and 6 are provided downstream of the overlapping roller pair 22. That is, sensors 5 and 6 are both provided in the section where body materials 10 and 11 are being intermittently fed. Sensor 5 is positioned so as to detect mark 100 (Figure 5A) affixed to body material 10 during a temporary stop in the intermittent feeding. Second sensor 6 is positioned so as to detect mark 110 (Figure 5B) affixed to body material 11 during a temporary stop in the intermittent feeding. In this example, both sensors 5 and 6 are cameras.

[0047] FIG. 5A shows the top surface of the upper body material 10. In this example, marks 100 are applied to the top surface of the upper body material 10 by printing or other means, repeatedly at a predetermined pitch along its length. FIG. 5B shows the bottom surface of the lower body material 11. Marks 110 are applied to the bottom surface of the body material 11 by printing or other means, repeatedly along its length. Marks 100 / 110 may be part or all of patterns 101 / 111 repeatedly applied to body materials 10 / 11 by printing or other means. Furthermore, marks 100, 110 may be the same or different in shape and position.

[0048] As shown in FIG. 6, the bag making machine further includes a controller 7. The sensors 5 and 6 and the actuators 32 and 41 are connected to the controller 7. The outputs from the sensors 5 and 6 are sent to the controller 7. The controller 7 generates control signals based on the outputs from the sensors 5 and 6 and sends them to the actuators 32 and 41 to control the actuators 32 and 41 as described below. The controller 7 includes one or more processors. The controller 7 performs the following control by having the one or more processors execute a program stored in a storage medium (not shown).

[0049] Controller 7 has position information on the bag making machine for sensors 5 and 6. Controller 7 then calculates the amount of deviation of body material 10 from its reference position and the amount of deviation of body material 11 from its reference position based on the outputs from sensors 5 and 6, and based on these, calculates the relative amount of deviation of body material 10 relative to body material 11 in the width direction (+Y, -Y) and the relative amount of deviation of body material 11 relative to body material 10 in the path direction (+X, -X). These relative amounts of deviation are quantities that indicate not only magnitude but also direction, for example, by using positive or negative values.

[0050] Here, the "reference position" refers to a position at which, when the detected marks 100, 110 are at that position during a temporary pause in intermittent feed, the bag making machine can produce bags 1 in which the patterns 101, 111 are perfectly aligned with one another. The reference position is known, and the controller 7 has this information. In this example, the sensors 5, 6 are cameras, and the controller 7 processes the output from the sensors (video or still image data) using a well-known method to determine the amount of deviation of the body materials 10, 11 from the reference position. In reality, it is difficult to align the patterns 101, 111 perfectly. Therefore, it is also possible to actually measure the amount of deviation of the patterns 101, 111 from the aligned position and set this amount of deviation as an "offset" value, thereby controlling the patterns 101, 111 to be aligned.

[0051] Note that, as long as the controller 7 can detect the relative amount of misalignment between the body materials 10, 11 based on the output, the sensors 5, 6 may be other sensors, such as line sensors, instead of cameras. If the marks 100, 110 are marks with clear boundaries, such as registration marks, a line sensor may be used. If the patterns 101, 111 do not include parts with clear boundaries like registration marks, the controller 7 may measure part or all of the patterns 101, 111 as marks 100, 110 using the output of the sensors 5, 6 (cameras) and a pattern search algorithm, and determine the relative amount of misalignment between the body materials 10, 11 based on the measurement results.

[0052] Next, the controller 7 controls the first correction mechanism 3 (the first actuator 32, or its motor in the above example) to move the body material 10 relative to the body material 11 to correct the misalignment in the width direction. The rotation amount of the first meandering correction rollers 30a, 30b (support 31) required to cancel the calculated relative misalignment in the width direction, and therefore the operation amount of the first actuator 32 corresponding to the rotation amount, are determined based on the relative misalignment in the width direction, the known structure of the first correction mechanism 3 (the distance between the meandering correction rollers 30a, 30b, the design of the support 31), etc. Note that the rotation amount and operation amount also indicate magnitude and direction. Therefore, the controller 7 can calculate the operation amount required to cancel the misalignment amount from the relative misalignment in the width direction, etc.

[0053] That is, based on the determined amount of relative misalignment in the width direction, the controller 7 generates a first control signal indicating the amount of actuation of the first actuator 32 required to correct the misalignment, and transmits the signal to the first actuator 32. In response to receiving the first control signal, the first actuator 32 operates by the determined amount of actuation to rotate the meandering correction rollers 30a, 30b (supports 31). As a result, the body material 10 is moved relative to the body material 11, and the relative misalignment in the width direction is corrected with the body material 11 as a reference.

[0054] 7A is an enlarged plan view of the body material 10 at the position of the sensor 5. For example, if the controller 7 determines based on the above-mentioned mark detection that the body material 10 is misaligned in the +Y direction by a distance D1 relative to the body material 11, it causes the first actuator 32 to rotate the support 31 in the -R direction (see FIGS. 2A and 2B). This moves the body material 10 in the -Y direction relative to the body material 11, correcting the relative misalignment in the width direction (reducing the misalignment distance D1).

[0055] On the other hand, when the controller 7 determines that the body material 10 is misaligned in the opposite direction -Y relative to the body material 11, it causes the first actuator 32 to rotate the support 31 in the direction +R. This moves the body material 10 in the direction +Y relative to the body material, correcting the relative misalignment in the width direction.

[0056] At the same time, the controller 7 controls the second correction mechanism 4 (the second actuator 41, its motor in the above example) to move the body material 11 relative to the body material 10, thereby correcting the deviation in the path direction. The amount of movement of the pitch correction roller required to cancel the determined amount of relative deviation in the path direction, and therefore the amount of operation of the second actuator 41 corresponding to that amount of movement, is determined based on the amount of relative deviation in the path direction, the known structure of the second correction mechanism 4, the feed path near the pitch correction roller 40, etc. The amount of movement also indicates the magnitude and direction. Therefore, the controller 7 can determine the amount of operation required to cancel the amount of deviation from the determined amount of deviation in the path direction, etc.

[0057] That is, based on the determined amount of relative deviation in the path direction, the controller 7 generates a second control signal indicating the amount of actuation of the second actuator 41 required to correct the deviation, and transmits it to the second actuator 41. In response to receiving the second control signal, the second actuator 41 operates by that amount of actuation, linearly moving the pitch correction roller 40. As a result, the body material 11 is moved relative to the body material 10, and the relative deviation in the path direction is corrected with the body material 10 as a reference.

[0058] 7B is an enlarged bottom view of the body material 11 at the position of the sensor 6. For example, if the controller 7 determines based on the above-mentioned mark detection that the body material 11 is misaligned in the direction +X by a distance D2 relative to the body material 10, the controller 7 causes the second actuator 41 to move the pitch correction roller 40 so as to increase the length of the feed path for the body material 11 (moving the pitch correction roller 40 downward in FIG. 4). This corrects the misalignment in the path direction (the misalignment distance D2 decreases when the next intermittent conveyance is temporarily stopped).

[0059] On the other hand, if the controller 7 determines that the body material 11 is misaligned by a distance D2 in the opposite direction -X relative to the body material 10, it causes the second actuator 41 to move the pitch correction roller 40 so as to shorten the feed path length of the body material 11 (moving the pitch correction roller 40 upward in FIG. 4). This corrects the relative misalignment in the path direction.

[0060] In addition, the controller 7 may determine the relative amount of deviation in the width direction / path direction each time the intermittent feed is temporarily stopped, generate the first / second control signal, and reflect the above-mentioned deviation correction in the width direction / path direction in the next intermittent feed.

[0061] Alternatively, the controller 7 may calculate the amount of deviation in the width direction / path direction each time the intermittent feed is temporarily stopped, calculate the average value of the relative deviation amounts in the width direction / path direction over the most recent consecutive multiple intermittent feeds, generate the first / second control signal based on the average value, and perform the above-mentioned correction of deviation in the width direction / path direction.

[0062] In this way, even if any relative misalignment occurs between the body materials 10, 11, it is automatically and immediately corrected. Therefore, the patterns 101, 111 are aligned with each other with precision downstream of the overlapping roller pair 22, and as a result, the patterns on the completed bag 1 are also aligned with precision.

[0063] In Patent Document 1, tension is applied to only one of the body materials to correct relative misalignment in two directions, which places a large load on that body material. In particular, the inclination of the tension in the width direction of the body material places a large load on the body material. On the other hand, in the embodiment, as described above, by slightly twisting one of the body materials 10, the relative misalignment in the width direction is corrected with respect to the other body material 11, and by adjusting the path length of the other body material 11, the relative misalignment in the path direction is corrected with respect to the one of the body materials 10. In particular, the slight twisting of the body material 10 in the embodiment places virtually no load on the body material compared to Patent Document 1. Therefore, the embodiment does not place an excessive load on either of the body materials.

[0064] More specifically, the configuration of Patent Document 1 forcibly generates large and small (uneven) tensions in the width direction, causing the body material to slide in the width direction on the selvage matching rolls, thereby placing a large load on the body material. On the other hand, in the embodiment, as shown in Figures 2A and 2B, when correcting the relative misalignment of the body materials 10, 11 in the width direction using the first correction mechanism 3 that twists the body material 10 at a small angle, tension is not forcibly applied in the width direction of the body material 10, nor is it forcibly caused to slide on the rollers. Therefore, in the embodiment, misalignment in the width direction can be corrected with almost no load on the body material, compared to Patent Document 1.

[0065] In this way, this embodiment does not place excessive load on only one of the body materials, and corrects widthwise misalignment with a lighter load than Patent Document 1, so it is particularly preferable for use in bag manufacturing using mono-material body materials 10, 11 that have higher extensibility than laminated film.

[0066] The method for correcting widthwise misalignment in Patent Document 1 involves forcibly tilting the selvedge roll to generate uneven tension across the width of the body material. In other words, the tension difference is generated by changing the length of the path at both ends of the body material. This tension difference is proportional to the driving force required to shift the upper body material across the selvedge roll in its widthwise direction (the axial direction of the selvedge roll). When comparing laminate film materials with monomaterial materials such as polyethylene or polyester, if the selvedge roll tilt angle is the same, the amount of change in the pathwise length at both ends of the body material will also be the same. The tension difference is greater for laminate film materials with low elasticity (high Young's modulus). Conversely, the tension difference is not as large for monomaterial materials with high elasticity (low Young's modulus). Therefore, the method in Patent Document 1 results in poor responsiveness in correcting widthwise misalignment.

[0067] In contrast, in the embodiment, the edge position of the body material 10 is directly moved by rotating the support 31 by a small angle, so the responsiveness is almost the same for laminate film materials and mono-material materials. It can be said that the embodiment is more suitable for mono-material materials than the above-mentioned correction method of Patent Document 1. Of course, applying unnecessary tension to the body material to correct misalignment is not good because it can damage the body material. A method that does not apply unnecessary tension to the body material, as in the embodiment, is more suitable.

[0068] In the above embodiment, the first correction mechanism 3 is assigned to the upper body material 10 and the second correction mechanism 4 is assigned to the lower body material 11. Alternatively, the first correction mechanism 3 may be assigned to the lower body material 11 and the second correction mechanism 4 may be assigned to the upper body material 10.

[0069] Furthermore, in this embodiment, the controller 7 adjusts the pitch amount (intermittent feed amount) of the intermittent feed of the feed device 20 based on the output from the sensor 5 (camera) or the sensor 6 (camera), thereby correcting any deviation of the marks 100, 110 (printed patterns 101, 111) from their reference positions (absolute positions on the bag-making machine) when the intermittent feed is temporarily stopped. That is, in addition to correcting the relative deviations in the two directions described above, this embodiment also corrects absolute deviations in the path direction. For this reason, the feed device 20 (its drive roller 200) is connected to the controller 7, as shown in FIG. 6.

[0070] As described above, the controller 7 calculates the amount of deviation of the mark 100 in the path direction from the reference position when the intermittent feed is temporarily stopped based on the output from the sensor 5.

[0071] Then, based on the calculated deviation, the controller 7 calculates the pitch amount for the next intermittent feeding of the body materials 10, 11 by the drive roller 200 immediately upstream of the processing device 23. More specifically, if the controller 7 determines that the mark 100 is located downstream of the reference position (the body materials 10, 11 are being fed in excess), it sets the pitch amount for the next intermittent feeding to be smaller than the set value (equivalent to one bag's worth). On the other hand, if the controller 7 determines that the mark 100 is located upstream of the reference position (the body materials 10, 11 are being fed insufficiently), it sets the pitch amount for the next intermittent feeding to be larger than the set value.

[0072] Then, the controller 7 controls the drive roller 200 so that the body materials 10, 11 are fed at the indexed (adjusted) pitch amount in the next intermittent feed.

[0073] Correcting only the relative deviation in the path direction can result in cumulative deviation in the path direction from the reference position. As described above, in addition to correcting the relative deviation, correction of the deviation in the path direction from the reference position is also performed. Therefore, if the sensor 5 and the drive roller 200 are located in a position upstream of and adjacent to the processing device 23, the body materials 10, 11 can be stopped with high precision at the designed position relative to the processing device 23. In other words, the processing device 23 can process the body materials 10, 11 with high precision, for example, by heat sealing them in the path direction or width direction.

[0074] In this way, the embodiment uses the sensor 5 to not only correct the relative positional deviation of the body materials 10, 11 in the width direction, but also correct the absolute positional deviation of the body materials 10, 11 in the path direction, thereby eliminating the need to install an additional sensor for correcting the absolute positional deviation.

[0075] The controller 7 may stop driving the drive roller 200 to temporarily stop the transport of the body materials 10, 11 the moment the sensor 5, such as a line sensor, detects the mark 100 (a specific point on the pattern 101), thereby aligning the mark 100 with a reference position. The mode of intermittent feed control (adjustment of the pitch amount) is selected appropriately depending on the required accuracy, bag design, etc.

[0076] Such intermittent feed control may be performed based on the output from the sensor 6 for the body material 11 instead of the sensor 5 for the body material 10. However, since the relative deviation in the path direction is corrected based on the body material 10, it is preferable that the intermittent feed control be performed using the output from the sensor 5 for the body material 10.

[0077] The bag making machine may further include a display device 25, as shown in Figure 8. The display device 25 may display image data (video data) from cameras serving as sensors 5 / 6 in real time on its display screen 250. The controller 7 may use information about the positions of the sensors 5 / 6 and the reference position to constantly superimpose and display the mark images RM1 / RM2 at the reference position. This allows the actual marks 100 / 110 on the body material 10 / 11 and the mark images RM1 / RM2 to be displayed on the display screen 250 when intermittent feeding is temporarily stopped.

[0078] In order to accurately determine the positions of the marks, it is preferable that the marks 100 and 110 have borders with strong contrast on both sides. In particular, when line sensors are used as the sensors 5 and 6, it is preferable that the marks 100 and 110 have borders parallel to the path direction in order to accurately determine the relative amount of deviation in the path direction.

[0079] Depending on the bag 1 to be manufactured, the patterns 101, 111 may differ between the body materials 10, 11, and the positions of the marks 100, 110 (parts of the patterns 101, 111 with strong contrast) to be detected may differ between the body materials 10, 11. In this case, the sensors 5, 6 (cameras) may be placed in different positions rather than facing each other.

[0080] Therefore, in order to accommodate the production of bags with various patterns, it is preferable that sensors 5 and 6 (cameras) be provided so that they can move in the width direction and the path direction. For example, as shown in FIG. 9, a movement mechanism 26 may be provided for sensor 5. Movement mechanism 26 may be a known mechanism, and may include, for example, two first frames 260 that are spaced apart in the width direction (+Y, -Y) and extend in the path direction (+X, -X), a second frame 261 that spans the first frames 260, extends in the width direction, and supports sensor 5 (camera), a rack and pinion (not shown) that moves second frame 261 and sensor 5 (camera) in the path direction on first frame 260, and a linear actuator (not shown) that moves sensor 5 (camera) in the width direction on second frame 261. A similar movement mechanism is provided for sensor 6.

[0081] The controller 7 can determine the positions of the sensors 5 and 6 (cameras) based on signals from the sensors and the like sent from the movement mechanism 26. Even when the sensors 5 and 6 (cameras) are shifted and placed in different positions to produce bags 1 in which the detected marks 100 and 110 (part of the printed patterns 101 and 111) are different from each other in the vertical and horizontal directions, as shown in Figure 10 (see parts P5 and P6 captured by sensors 5 and 6 (cameras) in Figure 10), the controller 7 can accurately correct the relative shifts in the width direction and path direction described above based on information such as the positions and reference positions of the sensors 5 and 6 (cameras).

[0082] It is particularly preferable to use such a moving mechanism 26 when low-resolution sensors 5, 6 (cameras) are used to capture images of a field of view narrower than one bag. If high-resolution sensors 5, 6 (cameras) are fixedly positioned so that one bag fits within their field of view, the moving mechanism 26 may not be necessary.

[0083] Another exemplary bag making machine shown in FIG. 11 further includes an additional sensor 8 provided downstream of sensors 5 and 6 and upstream of processing device 23 so as to detect mark 100 on body material 10. Controller 7 may control feed device 20 (drive roller 200) in any of the control modes described above based on the output from additional sensor 8, rather than the output from sensors 5 and 6, to correct any deviation of mark 100 from the reference position. Note that additional sensor 8 may be positioned so as to detect mark 110 on body material 11, but as described above, it is preferable that additional sensor 8 be positioned so as to detect mark 100 on body material 10. In this example as well, the processing accuracy by processing device 23 is improved.

[0084] Whether to use sensor 5 or to install additional sensor 8 to correct absolute positional deviation of body materials 10, 11 in the path direction is determined by various factors such as the number of processing steps, the size (length) of the bag making machine, the size of the bags to be manufactured, etc. In any case, the method disclosed above enables highly accurate positioning without placing excessive load on body materials 10, 11. [Explanation of symbols]

[0085] 1 bag 10,11 Body material 100,101 marks 20 Feeder 22 Pair of stacking rollers (stack members) 23 Processing equipment 3 First correction mechanism 30a, 30b meandering correction roller (first correction member) 32 First Actuator 4 Second correction mechanism 40 pitch correction roller (second correction member) 41 Second actuator 5,6 Sensors 7 Controller 8 additional sensors

Claims

1. A bag making machine that produces bags from at least a web-like first body material and a web-like second body material, a feeding device that feeds the first and second body materials in their longitudinal directions; a stacking member for stacking the first and second body materials together; a first correction mechanism including a first correction member disposed upstream of the overlapping member so as to engage with the first body material but not engage with the second body material, and a first actuator for moving the first correction member, the first correction mechanism moving the first correction member to twist the feed path of the first body material in a section including the first correction member; a second correction mechanism including a second correction member disposed upstream of the overlapping member, the second correction member engaging with the second body material but not engaging with the first body material, and a second actuator for moving the second correction member, the second correction mechanism moving the second correction member to vary the feed path length of the second body material; a first sensor for detecting marks repeatedly applied to the first body material; a second sensor for detecting marks repeatedly applied to the second body material; a controller for controlling the first and second actuators; The controller activating the first actuator based on outputs from the first and second sensors to correct a widthwise deviation of the first body relative to the second body perpendicular to the feed path; and actuating the second actuator based on the outputs from the first and second sensors to correct a deviation of the second body material in a path direction relative to the first body material. Bag making machine.

2. the first correction mechanism includes two meandering correction rollers arranged parallel to each other as the first correction member, and is configured to rotate the two meandering correction rollers in the same plane by the first actuator. The bag making machine according to claim 1.

3. the second correction mechanism includes a pitch correction roller as the second correction member, and is configured to linearly move the pitch correction roller in a direction perpendicular to an axis of the pitch correction roller by the second actuator. The bag making machine according to claim 1.

4. The controller a relative displacement amount of the first body material relative to the second body material in the width direction based on the outputs from the first and second sensors, a first control signal indicating an actuation amount of the first actuator based on the relative displacement amount in the width direction, and transmitting the first control signal to the first actuator; a relative deviation amount of the second body material relative to the first body material in the path direction based on the outputs from the first and second sensors, a second control signal indicating an actuation amount of the second actuator based on the relative deviation amount in the path direction, and the second control signal is generated and transmitted to the second actuator. The bag making machine according to claim 1.

5. The feeding device is configured to intermittently feed the first and second body materials, The first and second sensors are arranged to detect the marks on the first and second body materials, respectively, every time intermittent feeding is temporarily stopped. The bag making machine according to claim 4.

6. The controller The control device is configured to calculate the relative deviation amount in the width direction / path direction every time the intermittent feeding is temporarily stopped, and to generate the first control signal / the second control signal to be used in the next intermittent feeding based on the relative deviation amount. The bag making machine according to claim 5.

7. The controller and generating the first control signal / the second control signal based on an average value of the relative deviation amounts in the width direction / the path direction determined over a plurality of intermittent feeds. The bag making machine according to claim 5.

8. The controller and adjusting a pitch amount of intermittent feeding by the feeding device based on the output from either the first sensor or the second sensor. The bag making machine according to claim 1.

9. The controller determining the amount of deviation of the mark from a predetermined reference position when the intermittent feed is temporarily stopped based on the output from either the first sensor or the second sensor; calculating the pitch amount based on the calculated deviation amount; The feed device is configured to control the feed device so as to feed the first and second body materials at the indexed pitch amount. The bag making machine according to claim 8.

10. The controller configured to adjust the pitch amount based on the output from the first sensor. The bag making machine according to claim 8.

11. The bag making machine further comprises: a processing device that processes the first body material and / or the second body material; an additional sensor provided downstream of the first and second sensors and upstream of the processing device for detecting the mark on the first body material; The controller and adjusting the pitch amount of intermittent feeding by the feeding device based on the output from the additional sensor. The bag making machine according to claim 1.

12. A bag making method for manufacturing a bag from at least a web-shaped first body material and a web-shaped second body material, The bag making method includes: feeding the first and second body materials in their longitudinal directions by a feeding device; overlapping the first and second body members with an overlapping member; a controller determining a relative deviation amount of the first body material relative to the second body material in a width direction perpendicular to the path direction based on outputs from the first sensor and the second sensor; The controller determines a relative deviation of the second body material relative to the first body material in the path direction based on the outputs from the first and second sensors, The first sensor is configured to detect marks repeatedly applied to the first body material, The second sensor is configured to detect marks repeatedly applied to the second body material, The bag making method further comprises: The controller operates a first actuator based on the amount of deviation in the width direction to move a first correction member, thereby twisting the feed path of the first body material in a section including the first correction member, and correcting the first body material in the width direction based on the second body material; and The controller operates a second actuator based on the deviation amount in the path direction to move a second correction member, thereby varying the feed path length of the second body material, thereby correcting the second body material in the path direction based on the first body material, The first correction member is provided upstream of the overlapping member so as to engage with the first body material but not to engage with the second body material, The second correction member is arranged to engage with the second body material upstream of the overlapping member but not to engage with the first body material. Bag making method.

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