JP7459617B2 - Bag making machine, bag making machine control method, and bag manufacturing method - Google Patents

Description

The present invention relates to a bag making machine, a method for controlling the bag making machine, and a method for manufacturing bags.

In conventional bag making machines, misalignment of the sealing position due to the expansion and contraction of the plastic film used for making bags, or misalignment due to slippage during transport, was visually checked, and poor sealing was prevented by manually shifting the processing unit that processes the film depending on the amount of misalignment confirmed. In particular, when the film has a pattern printed repeatedly at a fixed interval (printing pitch), misalignment of the sealing position cannot be ignored, and poor sealing is a serious defect, so the visual confirmation of misalignment and the manual shifting work based on the results were very burdensome for the worker.

Patent Document 1 discloses a bag making machine that automatically solves the problem that the position of a printed pattern and the processing position (particularly the horizontal seal position, etc.) are misaligned due to the expansion or contraction of a plastic film.

JP 2010-105186 A

In the bag making machine described in Patent Document 1, when the printing pitch changes due to expansion and contraction of the plastic film, the amount of change in the printing pitch is determined based on the detection signal of the optical sensor. Based on the amount of variation in printing pitch and the detection signal, the processing unit is slightly displaced to a position where no deviation occurs between the position of the processing unit and the printing position. It has been proposed to increase production efficiency by automatically adjusting the position of the processing unit without manual adjustment. However, there are problems with the position adjustment accuracy of the processing unit and product loss at the start of production.

In other words, in the bag making machine described in Patent Document 1, the initial position of the processing unit is determined based on the design value of the printing pitch. Since the position is based on an ideal value that does not reflect the state of expansion and contraction, there is a lot of loss until the position is actually corrected and a good product can be produced.

In view of the above, the object of the present invention is to provide a bag making machine, a control method for the bag making machine, and a method for manufacturing bags that improve the accuracy of initial position adjustment of the processing unit and reduce product loss at the start of production.

The present invention provides a transport device that intermittently transports a long bag-making film on which at least reference marks are printed at a constant printing pitch, and a transport device that is movable forward and backward in the transport direction on the transport path of the long bag-making film. multiple processing units that perform predetermined processing on the long bag-making film when the long bag-making film is stopped, and multiple processing units that individually displace the multiple processing units to each target position. A unit driving device, a cutting unit that is placed at the forefront of the conveyance path of the long bag-making film and cuts the long bag-making film into individual pieces, and a cutting unit that is placed behind the cutting unit in the conveyance direction and marks the reference mark. The front mark sensor determines the stopping position of the long bag-making film by detecting it, and the reference mark is detected between the long bag-making film and the front stop position until it is conveyed a distance corresponding to the printing pitch. A processing unit displacement control means in a bag making machine comprising: a rear mark sensor disposed at a position possible and at a position rearward in the conveying direction from a rearmost processing unit among a plurality of processing units; and a processing unit displacement control means. stores the conveyance amount from the previous stage's stop position until the rear mark sensor detects the reference mark as the reference mark sensor offset distance, and calculates the long length from the difference in the stored reference mark sensor offset distance before and after the predetermined period of conveyance. Calculate the amount of expansion and contraction of the bag film within the device, calculate the target positions of multiple processing units individually based on the amount of expansion and contraction within the device, and individually control the displacement of the multiple processing unit drive devices so that they are displaced to the target positions. , a bag making machine and its control method.

In the bag making machine and the control method thereof, the processing unit displacement control means further has a presetting means for presetting the multiple processing units to their respective positions before production begins, and the processing unit displacement control means has a function of storing the production item and each position of the multiple processing units as the production item progresses, and the presetting means may individually control the displacement of the multiple processing unit drive devices so as to displace each of the multiple processing units to each preset position by storing each position of the multiple processing units stored when the same production item was previously produced.

The present invention is a method for manufacturing bags manufactured by a bag making machine, and the bag making machine comprises two or more long bag making films each having reference marks printed at a constant printing pitch on at least one of them. A conveyor device that overlaps and conveys intermittently, and a conveyor device that is disposed on the conveyance path of the long bag-making film so that it can be displaced forward and backward in the conveyance direction, and is used for long bag-making when the long bag-making film is stopped. A plurality of horizontal sealing units that perform heat treatment on the film for horizontal sealing, a plurality of processing unit drive devices that individually displace the plurality of horizontal sealing units to each target position, and a transport path for the long bag-making film. A cutting unit that is placed at the forefront and cuts the long bag-making film, and a front mark sensor that is placed behind the cutting unit in the conveying direction and determines the stopping position of the long bag-making film by detecting a reference mark. , a position where the reference mark can be detected until the long bag-making film is transported from the previous stop position to a distance corresponding to the printing pitch, and transported from the rearmost horizontal sealing unit among the multiple horizontal sealing units. The apparatus includes a rear mark sensor disposed at a rearward position in the direction, and a machining unit displacement control means for individually controlling displacement of a plurality of machining unit drive devices.

The bag manufacturing method includes at least a horizontal sealing process in which two or more layers of long bag-making film are conveyed in a stack and heated multiple times by multiple horizontal sealing units to seal the film horizontally, and a cutting process in which the long bag-making film is cut into individual pieces by a cutting unit after the horizontal sealing process. The processing unit displacement control means stores the amount of conveyance from the stop position of the previous stage until the rear mark sensor detects the reference mark as the reference mark sensor offset distance, calculates the amount of expansion and contraction of the long bag-making film within the device from the difference between the stored reference mark sensor offset distances before and after a predetermined period of conveyance, individually calculates target positions for the multiple horizontal sealing units based on the amount of expansion and contraction within the device, and individually controls the displacement of the multiple processing unit drive devices so that the film is displaced to the target positions.

In the above bag manufacturing method, the processing unit displacement control means further includes a presetting means for presetting the multiple horizontal sealing units to their respective positions before production begins, and the processing unit displacement control means has a function of storing the production item and the respective positions of the multiple horizontal sealing units as the production item progresses, and the presetting means may individually control the displacement of the multiple processing unit drive devices so that the multiple horizontal sealing units are displaced to each preset position, with the respective positions of the multiple horizontal sealing units stored when the same production item was previously processed being treated as the respective preset positions.

The present invention provides a bag making machine, a control method for the bag making machine, and a method for manufacturing bags that improve the accuracy of initial position adjustment of the processing unit and reduce product loss at the start of production.

A perspective view showing an overview of the overall configuration of a bag making machine according to an embodiment of the present invention FIG. 1 is a diagram showing a state of a long bag-making film being intermittently conveyed in a bag-making machine according to the present invention;

[Bag making machine]
The bag making machine according to the present invention will be described below with reference to the drawings. Note that the drawings shown below are schematic views, and the size, shape, thickness, gaps, decoration, etc. of each part are appropriately exaggerated or simplified to facilitate understanding. Also, configurations that are not directly related to the description are appropriately omitted. Note that in the drawings below, the same parts are given the same reference numerals, and some detailed descriptions may be omitted.

In the following description, specific numerical values, shapes, materials, etc. are given, but these can be changed as appropriate.
In this specification, the terms sheet, film, etc. are used, but in general usage, sheets are thicker than films, and this specification follows suit. However, such distinction in usage has no technical meaning, and the essence of the present invention and the interpretation of the claims will not change even if these terms are appropriately replaced.

(Embodiment)
FIG. 1 is a perspective view showing an outline of the overall configuration of a bag making machine 10 according to an embodiment of the present invention.
The bag making machine 10 is equipped with a conveying device 11 that intermittently conveys a long bag making film (or sheet) (hereinafter, long bag making film 1). The conveying device 11 unwinds a raw roll 2 on which the long bag making film 1 is wound in a roll shape and conveys it in its longitudinal direction. As shown in Fig. 1, two raw rolls 2 are shown, and in the bag making machine 10 and the conveying device 11, two sheets of the long bag making film 1 are overlapped, and are conveyed intermittently from right to left in Fig. 1 while being heat sealed (vertical seal and horizontal seal).
In this description, attention will be focused on the conveying direction in the bag making machine 10 and the conveying device 11, and the side toward the raw fabric roll 2 (the right side in FIG. 1) will be referred to as the rear or upstream, and the side opposite the raw fabric roll 2 (the side toward a cutting unit 29 described below, the left side in FIG. 1) will be referred to as the front or downstream. In other words, the long bag-making film 1 is conveyed in the direction from the raw fabric roll 2 toward the cutting unit 29, from rear to front and from upstream to downstream.

The long bag making film 1 is generally a plastic film, on which the same printed pattern (including letters, etc.) is repeatedly printed at a fixed interval. In this description, the fixed interval at which the same printed pattern is repeatedly printed is referred to as the printing pitch P. A reference mark 3 is usually included as part of the printed pattern, and the reference mark 3 is also printed at the above-mentioned fixed printing pitch P. The reference mark 3 is used for transport control of the transport device 11, displacement control of each processing unit described later, etc.

A large number of pairs of upper and lower nip rolls 13 (only some of which are shown) are arranged along the transport path of the transport device 11. These pair of upper and lower nip rolls 13 convey two stacked long bag-making films 1 while sandwiching them therebetween. The nip roll 13 is rotationally driven by a drive motor 15 via, for example, a timing belt. The conveyance device 11 further includes a conveyance control device 12, an encoder 14, and an optical sensor 16. The encoder 14 is attached to, for example, the rotating shaft of the nip roll 13 (or the rotating shaft of the drive motor 15, or any other shaft that rotates in synchronization with this), and controls the length of the long bag-making film 1 by the nip roll 13 based on the amount of rotation. Used to measure conveyance amount (conveyance distance). The output signal of the encoder 14 is given to the conveyance control device 12. The optical sensor 16 includes a front mark sensor 32 and a rear mark sensor 33, which will be described later, and detects the reference mark 3 printed on the long bag-making film 1, and is arranged at an appropriate position on the conveyance path. The optical sensor 16 outputs a detection signal (for example, a pulse representing the leading edge of the reference mark 3 as a rising edge) every time the reference mark 3 passes through its mounting position, and provides the detection signal to the conveyance control device 12 .

The conveying control device 12 controls the drive motor 15 (and therefore the nip roll 13) to rotate intermittently. That is, the conveying of the long bag-making film 1 is repeated intermittently, and the long bag-making film 1 stops between conveyances. During this stop time, various processes (sealing, punching, cutting, etc.) are performed on the long bag-making film 1 to make bags. The conveying amount (conveying distance) per conveyance (intermittent conveyance) repeated intermittently by the conveying device 11 corresponds to the printing pitch P, i.e., the distance (length) between adjacent reference marks 3.

Along the conveyance path of the conveyance device 11, from the upstream side (backward in the conveyance direction, right side in FIG. 1) to the downstream side (front in the conveyance direction, left side in FIG. 1), a vertical sealing unit 21 (not shown), a vertical cooling unit, unit (not shown), horizontal seal unit 24, horizontal seal unit 25, horizontal seal unit 26, horizontal cooling unit (not shown), and cutting unit 29 are arranged in this order. The units in the bag making machine 10 are not limited to those described above, and other units such as a punch unit may be included, or one or more of the above units may be omitted. These units are collectively referred to as processing units (processing equipment). Each processing unit is supported so as to be movable (position adjustable) in the direction along the conveyance direction (back and forth). Some processing units may not be movable but may be fixed. Processing (sealing, cooling, cutting, etc.) by these processing units is performed while the conveyance of the long bag-making film 1, which is intermittently conveyed, is stopped. Therefore, at the stop position of the long bag-making film 1, each processing unit is controlled to be displaced to an optimal position by the method described below so that the long bag-making film 1 can be processed at an appropriate position.

The horizontal seal units 24, 25, and 26 are displacement-controlled and driven in a direction along the conveyance direction (front-back direction) by processing unit drive devices 34, 35, and 36 each including a motor. Similarly, the vertical seal unit 21 can be controlled to be displaced in the forward and backward transport direction by another processing unit drive device corresponding thereto. Other units may also be driven under displacement control in the same manner. In this description, in order to explain the essence of the invention concisely, a case where there are three lateral seal units will be described assuming that only the lateral seal units are driven under displacement control.

The front mark sensor 32 is arranged at the rear (upstream side) in the conveyance direction of the cutting unit 29, and the front mark sensor 32 is arranged at the rear (upstream side) in the conveyance direction of the horizontal seal unit 24 which is the most rearward (upstream side) in the conveyance direction among the horizontal seal units 24, 25, and 26. A rear mark sensor 33 is arranged on the side). The front mark sensor 32 and the rear mark sensor 33 included in the optical sensor 16 detect the reference mark 3 printed on the long bag-making film 1 (for example, the output signal is the same as the output signal of the optical sensor 16). (The timing for detecting the reference mark 3 is determined by the rise of the output signals of these optical sensors.)

The long bag-making film 1 is intermittently conveyed by a distance corresponding to the printing pitch P as described above. Specifically, the detection of the reference mark 3 by the front mark sensor 32 is the trigger for stopping the conveyance, and since the interval between the reference marks 3 is the same as the printing pitch P, as a result, the distance between the reference marks 3 and the printing pitch P is the same as that of the printing pitch P. Transported intermittently.
By the way, as described above, in the conveying device 11 of the bag making machine 10, the printing pitch is not strictly constant mainly due to the expansion and contraction of the long bag making film 1. The reason why the front mark sensor 32 is used as a trigger to stop the conveyance is that the cutting process has the greatest negative effect on positional deviation during processing in the bag making machine 10. This is to reduce the displacement of the cutting position by stopping the conveyance with the trigger of the sensor 32.

The rear mark sensor 33 also detects the reference mark 3. By detecting the rear mark sensor 33, it is possible to grasp the distance from the transport start position at the installation position of the rear mark sensor 33 to the reference mark 3 (reference mark sensor offset distance). If the printing pitch P of the long bag-making film 1 in the conveyance device 11 is always constant, the reference mark sensor offset distance should always be constant, but in reality, the reference mark sensor offset distance is It changes as it progresses (time). In the present invention, based on the change in the reference mark sensor offset distance, the processing unit displacement control device 31, which is a processing unit displacement control means, controls the displacement of the horizontal seal units 24, 25, and 26 in the forward and backward positions along the conveyance direction. It is something. The detailed method will be described later.

The vertical seal unit 21 heats and fuses (seals) one or more rows of the two-ply long bag-making film 1 by the length of one printing pitch to form a vertical seal portion. The vertical cooling unit cools the fused vertical seal portion. The horizontal seal units 24, 25, and 26 are arranged at intervals of an integer multiple (2 times in the figure) of one printing pitch P, and these three horizontal seal units 24, 25, and 26 heat the same location of the two-ply long bag-making film 1 to form a horizontal seal portion. The horizontal cooling unit cools the horizontal seal portion. The cutting unit 29 cuts the long bag-making film 1 in the width direction (horizontal direction) along the cutting line 5 in or near the horizontal seal portion to form individual pieces. In this way, bags 8 with three sealed sides are produced in individual pieces for each printing pitch from the two-ply long bag-making film 1. Note that the cutting line 5 is not usually printed, but is illustrated here for convenience as an ideal cutting position.

Further, there is a vertical cutting unit further behind (upstream side) in the conveyance direction from the cutting in the width direction, and even if the long bag-making film 1 is cut in the longitudinal direction (longitudinal direction) so as to be divided in the width direction. good. For example, if there is a vertical cutting unit adjacent to the upstream side of the cutting unit 29, the vertical cutting unit and the cutting unit 29 can cut the bag 8 into individual pieces even if the bag 8 is cut on multiple sides in the width direction. can do.
Furthermore, even if only one fabric roll 2 is supplied to the conveyance device 11 in the bag making machine 10, a vertical cutting unit is present downstream of the fabric roll 2 and most upstream of each processing unit. In this case, one long bag-making film 1 supplied from the raw roll 2 is divided into, for example, two pieces in the width direction by the vertical cutting unit, and the two long bag-making films 1 are divided into two pieces in the width direction by the longitudinal cutting unit. By overlapping the films 1, two overlapping long bag-making films 1 to be processed by the present bag-making machine 10 may be obtained.

As described above, the bag making machine 10 of the present invention includes, as an example, a conveying device 11, a plurality of processing units (vertical sealing unit 21, horizontal sealing units 24, 25, 26, etc.), a plurality of processing unit driving devices (34, 35, 36), a cutting unit 29, a front mark sensor 32, a rear mark sensor 33, and a processing unit displacement control means (processing unit displacement control device 31).
The conveying device 11 intermittently conveys the long bag-making film 1 on which at least the reference marks 3 are printed at a constant printing pitch P.
Multiple processing units (vertical sealing unit 21, horizontal sealing units 24, 25, 26, etc.) are arranged on the conveying path of the long bag making film 1 so that they can be displaced forward and backward in the conveying direction, and perform predetermined processing on the long bag making film 1 when the long bag making film 1 is stopped.
The multiple machining unit driving devices (34, 35, 36) individually displace the multiple machining units to the designated target positions.

The cutting unit 29 is disposed at the forefront of the conveyance path of the long bag-making film 1, and cuts the long bag-making film 1 into individual pieces.
The front mark sensor 32 is arranged at the rear of the cutting unit 29 in the transport direction, and determines the stopping position of the long bag-making film 1 by detecting the reference mark 3.
The rear mark sensor 33 is located at a position where the reference mark 3 can be detected while the long bag-making film 1 is conveyed from the previous stop position to the distance corresponding to the printing pitch P, and at a position where the reference mark 3 is detected by the plurality of processing units (21 , 24, 25, 26, etc.), which is located at a position rearward in the conveyance direction from the rearmost processing unit.
The processing unit displacement control means (processing unit displacement control device 31) stores the amount of transport from the previous stage stop position until the rear mark sensor 33 detects the reference mark 3 as the reference mark sensor offset distance, and carries out the transport at a predetermined period. The amount of expansion and contraction within the device of the long bag-making film 1 is calculated from the difference between the reference mark sensor offset distances stored before and after, and the processing units (21, 24, 25, 26, etc.), and individually controls the displacement of a plurality of processing unit drive devices (34, 35, 36, etc.) so as to move to the target positions.

<Control method of bag making machine (horizontal sealing unit)>
The control of each of the processing unit drive devices (34, 35, 36) by the processing unit displacement control device 31, that is, the displacement control of the horizontal sealing units (24, 25, 26) is specifically performed as follows.
The bag making machine 10 according to the present invention performs intermittent operation based on the detection signal of the front mark sensor 32. In reality, even if the front mark sensor 32 detects the reference mark 3, it is difficult to immediately stop the machine in intermittent operation due to a time lag or the inertia of the conveying device 11, but in this description, for the sake of simplicity, it is assumed that the machine stops in intermittent operation at the same time as the front mark sensor 32 detects it. Since the distance from the position where the reference mark 3 is detected to the actual stop is considered to be constant during the production process, there is no problem with simplifying it as described above. Also, for the sake of simplicity, only the horizontal sealing units (24, 25, 26) are shown and described as the multiple processing units of the bag making machine 10, i.e., the objects of displacement control.

In addition, in this explanation, the front mark sensor 32 and the rear mark sensor 33 detect the reference mark 3 printed on the long bag-making film 1, but the present invention is not limited to this, and the front mark sensor 32 and the rear mark sensor 33 detect the reference mark 3 printed on the long bag-making film 1. A part of the reference mark 3 may be used as a detection target instead of the reference mark 3. In that case, the detection target of the front mark sensor 32 and the rear mark sensor 33 needs to be part of the same picture pattern.
In this way, when the detection target of the front mark sensor 32 and the rear mark sensor 33 is a part of the picture pattern, the part of the picture pattern that is the detection target substantially plays the same role as the reference mark 3 in the present invention. In order to achieve this, the present invention is applied assuming that a part of the picture pattern to be detected is the reference mark 3.

In this description, the positions of the cutting unit 29 and the rear mark sensor 33 are fixed. The position of the front mark sensor 32 is adjusted according to the distance between the cutting position and the reference mark 3, which varies depending on the product being produced, but the position of the front mark sensor 32 is also fixed while production of non-defective products is in progress. This is not limited to the present invention, and for example, the positions of the front mark sensor 32 and the rear mark sensor 33 may be fixed, and the position of the cutting unit 29 may be variable depending on the product being produced. In any case, while production is in progress, the positions of the front mark sensor 32 and the rear mark sensor 33 are fixed, i.e., the distance between the front mark sensor 32 and the rear mark sensor 33 is constant.

At the start of production, first, the position of the front mark sensor 32 and the position of each horizontal seal unit (24, 25, 26) are preset. The front mark sensor 32 and each horizontal seal unit (24, 25, 26).

The position of the forward mark sensor 32 is determined so that the cutting position of the cutting unit 29 is the ideal cutting position of the forward bag-making film 1. In this state, the position of the forward mark sensor 32 is manually adjusted while checking the output (detected or not detected) of the forward mark sensor 32 so that the front outline of the reference mark 3 is the detection position of the forward mark sensor 32.

Regarding the position of each horizontal seal unit (24, 25, 26), before starting production of non-defective products, operate the bag making machine 10 in a preset position, and set the position of each horizontal seal unit (24, 25, 26) The position of each horizontal seal unit (24, 25, 26) is manually adjusted while visually confirming the horizontal seal position on the long bag-making film 1. Here, manual means not only that the operator actually moves the position of each horizontal seal unit (24, 25, 26) by hand, but also the processing unit drive that drives each horizontal seal unit (24, 25, 26). This also includes the operator manually inputting numerical values of position coordinates and signals such as forward and backward movement to the processing unit displacement control means that individually controls the displacement of the apparatus. After the manual adjustment, production of non-defective products is started.

In the present invention, the preset positions of each horizontal seal unit (24, 25, 26) are set at the time when the same bag making machine 10 started producing good products when the same production item was processed last time. It is preferable to set each position as (24, 25, 26).
That is, the processing unit displacement control device 31 (processing unit displacement control means) further includes presetting means for presetting each horizontal seal unit (24, 25, 26) (a plurality of processing units) to each position before starting production. The processing unit displacement control device 31 (processing unit displacement control means) has a function of storing a production item and each position of each horizontal seal unit (24, 25, 26) when the production item advances. . The presetting means sets each position of each horizontal seal unit (24, 25, 26) stored when the same production item was produced in the past as each preset position, and sets each (a plurality of) positions so as to be displaced to each preset position. ) Preferably, the displacement of the processing unit drive devices (34, 35, 36) is individually controlled.

According to the presetting method for each of the horizontal seal units (24, 25, 26), the time required for the manual adjustment can be shortened compared to the case where the horizontal seal units (24, 25, 26) are preset based on the design values of the production item. Product loss associated with manual adjustment can be reduced. Similar effects can be obtained with the bag 8 manufactured using this presetting method.
The reason for this is that the long bag-making film 1 set at the most upstream side of the bag-making machine 10 is wound at the center of the roll 2, compared to its outer periphery (outside the winding). In many cases, the area near the winding core is slightly deformed so that the long bag-making film 1 is relatively stretched. Therefore, the printing pitch P (that is, the interval between the reference marks 3) of the long bag-making film 1 is slightly different between the vicinity of the outside of the roll and the vicinity of the core of the roll. Since the long bag making film 1 at the time of the previous production start of non-defective products and the long bag making film 1 at the start of the current production of non-defective products are usually long bag making films 1 near the outside of the roll, A possible reason for this is that the printing pitch is often more in line with reality than by applying design data.

After the positions of the horizontal seal units (24, 25, 26) are preset, the horizontal seal positions are visually checked and manually adjusted, and then the production of good products is started. As described above, during the progress of good products, the positions of the cutting unit 29 and the rear mark sensor 33 are fixed, so the distance between the cutting unit 29 and the rear mark sensor 33 is constant, and this distance is called DS. DS is stored in the processing unit displacement control device 31 (processing unit displacement control means). The position coordinates of the rear mark sensor 33, which are fixed regardless of the production item, are registered in advance in the processing unit displacement control device 31. Although the position coordinates of the cutting unit 29 can be finely adjusted after the start of production, they are basically fixed regardless of the production item, so they are registered in advance in the processing unit displacement control device 31. In this way, the processing unit displacement control device 31 is aware of the coordinate positions of the cutting unit 29 and the rear mark sensor 33, so it can calculate and store the above DS based on them.

For the sake of explanation, each horizontal sealing unit (24, 25, 26) is classified as the first horizontal sealing unit 24, the second horizontal sealing unit 25, and the third horizontal sealing unit 26, starting from the one installed upstream of the bag making machine 10. When the non-defective product starts to move, the distance between the cutting unit 29 and the first horizontal sealing unit 24 is DH1s, the distance between the cutting unit 29 and the second horizontal sealing unit 25 is DH2s, and the distance between the cutting unit 29 and the third horizontal sealing unit 26 is DH3s. The processing unit displacement control device 31 can calculate and store the distances DH1s, DH2s, and DH3s in the same manner as above.

As mentioned above, on the long bag-making film 1, the same pattern is ideally repeatedly printed at constant intervals (printing pitch P). In the bag 8 manufactured from the long bag-making film 1 by the bag-making machine 10, it is natural that the printed pattern, the horizontal seal position, and the cutting position are synchronized, that is, the mutual positional relationship is constant. required. Therefore, not only the printed pattern but also the interval between the horizontal seal positions and the interval between the cutting positions on the long bag-making film 1 are required to have the above-mentioned constant printing pitch P.

The operation of the conveying device 11 in the bag making machine 10 is repeated intermittently, stopping when the front mark sensor 32 detects the reference mark 3 on the long bag making film 1 being conveyed, stopping for a fixed time (e.g., 0.5 seconds), restarting conveyance, and then stopping again when the front mark sensor 32 next detects the reference mark 3. During the fixed time stoppage, predetermined processing (heat sealing, cutting, etc.) is performed in each processing unit (21, 24, 25, 26, etc.).
As described above, when the intermittent operation is stopped, the front edge of the reference mark 3 is located at the detection position of the front mark sensor 32 .

On the other hand, when the intermittent operation is stopped, the front outline of the reference mark 3 is usually not located at the detection position of the rear mark sensor 33. In the stopped state, the distance from the detection position of the rear mark sensor 33 to the front contour of the nearest reference mark 3 in the upstream direction is referred to as reference mark sensor offset distance X.
Here, the reference mark sensor offset distance X can be understood as follows. FIG. 2 shows the long bag-making film 1 that is intermittently conveyed in the bag-making machine 10. FIG. 2(a) shows a state in which the intermittent operation is stopped at the start of production of non-defective products. The reference mark sensor offset distance X is the distance of the part shown in FIG. 2(a), but the processing unit displacement control device 31 does not know the reference mark sensor offset distance X at the time of FIG. 2(a). .
Here, the reference mark sensor offset distance X at the time of starting production of non-defective products is defined as the starting reference mark sensor offset distance Xs.

FIG. 2B shows the state at the time when the rear mark sensor 33 detects the front outline of the reference mark 3 after transport is started from the state shown in FIG. 2A. However, the intermittent operation does not stop at the position of the long bag-making film 1 shown in FIG. 2(b). Regarding the conveyance distance of the long bag-making film 1 from the stopped state shown in FIG. 2(a) until the rear mark sensor 33 detects the reference mark 3 shown in FIG. 2(b), the processing unit displacement control device 31 This can be determined from the signal of an encoder 14 installed on the nip roll 13 or the like so as to be synchronized with the movement of the long bag-making film 1. That is, the number of pulses output from the encoder 14 from the start of transport until the rear mark sensor 33 detects the reference mark 3 may be counted, and the transport distance of the long bag-making film 1 may be determined from the number of pulses. The conveyance distance of the long bag-making film 1 from the state of FIG. 2(a) to the state of FIG. 2(b) is, for example, the distance of the long bag-making film 1 shown in FIG. This is the displacement distance in the transport direction from the position of the long bag-making film 1 shown in (b), that is, the distance X in the illustration.
In this way, the reference mark sensor offset distance X at the start of production of non-defective products (at the start of measurement), that is, the reference mark sensor offset distance at the start Xs, can be obtained, and the reference mark sensor offset distance at the start Xs is determined by the machining unit displacement control device. 31 (processing unit displacement control means).

FIG. 2(c) shows a state in which the intermittent operation is stopped after the production of non-defective products has progressed to a certain extent from the start of the measurement shown in FIG. 2(a). As production progresses, the long bag-making film 1 is unwound from the original fabric roll 2 from a position closer to the core of the original fabric roll than at the start of production of non-defective products. Therefore, the long bag-making film 1 at the time of FIG. 2(c) has been slightly deformed so as to stretch compared to when production of non-defective products started, and the printing pitch P has become slightly larger than when production of non-defective products started. ing.

In FIG. 2(c), the state is shown in an exaggerated manner. In FIG. 2(c), the above-mentioned stretching deformation causes each horizontal seal position to deviate significantly from the ideal position. The above-mentioned reference mark sensor offset distance X at the time of FIG. 2(c) is called the end reference mark sensor offset distance Xe. The end reference mark sensor offset distance Xe is the distance shown in FIG. 2(c). The end reference mark sensor offset distance Xe can also be obtained in the same manner as described for the reference mark sensor offset distance X (start reference mark sensor offset distance Xs) in FIG. 2(a) and FIG. 2(b), and is similarly stored in the processing unit displacement control device 31 (processing unit displacement control means). The time when the conveying operation at which the end reference mark sensor offset distance Xe can be obtained by the above-mentioned method is completed and stopped is regarded as the end of measurement. Strictly speaking, the end of measurement is one period after the state shown in FIG. 2(c), but since the amount of expansion and contraction at one printing pitch P can be almost negligible, there is no problem in using FIG. 2(c) as a diagram showing the end of measurement.
The printing pitch P at the start of the measurement, i.e., in FIGS. 2(a) and 2(b), is shown as Ps, and the printing pitch P at the end of the measurement, i.e., in FIGS. 2(c) and 2(d), is shown as Pe.

In the states of Figures 2(a) and 2(c), the reference mark 3 located immediately upstream (rear) of the rear mark sensor 33 is referred to as the rear mark sensor reference mark 3b. Here, in the states of the long bag-making film 1 in Figures 2(a) and 2(c), the distance from the cutting unit 29 to the rear mark sensor reference mark 3b can be expressed as "DS+Xs" in the state of Figure 2(a) (at the start of measurement) and as "DS+Xe" in the state of Figure 2(c) (at the end of measurement), as shown. Then, it can be said that the distance from the cutting unit 29 to the rear mark sensor reference mark 3b in the long bag-making film 1 in the state of Figure 2(c) (at the end of measurement) is extended by "Xe-Xs" compared to the state of Figure 2(a) (at the start of measurement).
In other words, if the increase or decrease in the distance from the cutting unit 29 to the rear mark sensor reference mark 3b on the long bag-making film 1 at the end of measurement relative to the start of measurement, i.e., the amount of expansion or contraction, is referred to as the amount of expansion or contraction within the device, then the amount of expansion or contraction within the device can be expressed as "Xe-Xs".

As described above, in the state shown in FIG. 2(c), each horizontal seal position is shifted from the ideal position, so the position of each horizontal seal unit (24, 25, 26) should also be displacement-controlled in accordance with the above-mentioned expansion and contraction (stretch) of the long bag-making film 1. FIG. 2(d) shows the state after the positions of each horizontal seal unit (24, 25, 26) have been displaced from the state shown in FIG. 2(c) by the displacement control according to the present invention. In the state shown in FIG. 2(d), the first horizontal seal unit 24 has been displaced by ΔDH1, the second horizontal seal unit 25 by ΔDH2, and the third horizontal seal unit 26 by ΔDH3 (see each figure) compared to the state shown in FIG. 2(c).

Hereinafter, a method for determining the displacement amount (ΔDH1, ΔDH2, ΔDH3) of each horizontal seal unit (24, 25, 26) according to the present invention will be explained.
Regarding the expansion and contraction of the long bag-making film 1, considering the causes of expansion and contraction, it is difficult to imagine local expansion and contraction, and it is thought that the long bag-making film 1 as a whole expands and contracts with a large trend. Therefore, it is safe to assume that the long bag-making film 1 expands and contracts evenly from the cutting unit 29 to the rear mark sensor reference mark 3b. Therefore, in the present invention, regarding the amount of expansion/contraction within the device (Xe-Xs), the cutting unit 29 relative to the distance (DS+Xs) from the cutting unit 29 to the rear mark sensor reference mark 3b in the state of FIG. It is proportionally distributed based on the ratio of the distance (DH1s, DH2s, DH3s) from to each horizontal seal unit (24, 25, 26).

That is, the respective displacement amounts (ΔDH1, ΔDH2, ΔDH3) of the first horizontal sealing unit 24, the second horizontal sealing unit 25, and the third horizontal sealing unit 26 can be calculated by the following formula.
ΔDH1=(Xe-Xs)×DH1s/(DS+Xs)
ΔDH2=(Xe−Xs)×DH2s/(DS+Xs)
ΔDH3=(Xe−Xs)×DH3s/(DS+Xs)

Here, if (Xe-Xs) is positive, then ΔDH1, ΔDH2, and ΔDH3 will also be positive values, but if they are positive, then the long bag-making film 1 has stretched compared to when the measurement began, and is displaced to the right by the distances ΔDH1, ΔDH2, and ΔDH3, respectively, as shown in Figure 2 (d).
Conversely, if (Xe-Xs) is negative, ΔDH1, ΔDH2, and ΔDH3 will also be negative values, but if they are negative, the long bag-making film 1 will have shrunk compared to when the measurement began, and will be displaced to the left by the distances ΔDH1, ΔDH2, and ΔDH3, respectively.

From the above, the distance between the cutting unit 29 and the first lateral seal unit 24 at the time of completion of the displacement control shown in FIG. 2(d) is DH1e, and the distance between the cutting unit 29 and the second lateral seal unit 25 is DH2e. The distance between the cutting unit 29 and the third horizontal seal unit 26 is DH3e. DH1e, DH2e, and DH3e, which are also target positions for displacement control, can be expressed by the following equations.
DH1e=DH1s+ΔDH1
DH2e=DH2s+ΔDH2
DH3e=DH3s+ΔDH3

The timing for controlling the displacement of the first horizontal sealing unit 24, the second horizontal sealing unit 25, and the third horizontal sealing unit 26 is appropriately the time of the next conveying operation (during conveying) following the conveying operation (during conveying) that detects the distance Xe of the intermittent conveying of the long bag-making film 1 in the conveying device 11, but is not limited to this.
In the intermittent conveying in the conveying device 11, if one cycle is defined as the period from the start of a conveying operation to the start of the next conveying operation, the displacement control thereafter may be performed as follows. While maintaining the start reference mark sensor offset distance Xs at the start of production of a non-defective product (start of measurement), the end reference mark sensor offset distance Xe is grasped and updated in the same manner as above for each predetermined cycle. The updated end reference mark sensor offset distance Xe is then applied to the above formula to calculate and update the target positions DH1e, DH2e, and DH3e for the displacement control, and each of the horizontal sealing units (24, 25, 26) is displaced. Such displacement control may be repeated for each predetermined cycle.

As mentioned above, FIG. 2(c) shows the expansion and contraction (elongation in FIG. 2(c)) of the long bag-making film 1 in an exaggerated manner. In reality, displacement control should be performed somewhat frequently so that the displacement of the machining position in each machining unit (21, 24, 25, 26, etc.) always falls within each allowable range. The frequency of the displacement control, ie, the predetermined cycle, is preferably about 1 to 500 cycles, preferably about 12 to 60 cycles. With this degree of displacement control frequency, each positional shift of the processing position in each processing unit (21, 24, 25, 26, etc.) is within the allowable range, considering the actual amount of expansion and contraction of the long bag-making film 1. It is difficult to imagine that the drive unit will come off, and since the operating load on each drive unit can be reduced, the durability of the drive unit can be improved.

Furthermore, in the above description, a case has been described in which the displacement of three processing units, the first lateral seal unit 24, the second lateral seal unit 25, and the third lateral seal unit 26, is controlled. However, the number of machining units whose displacements are controlled is not limited to three, but may be one or more. Furthermore, the type of machining unit whose displacement is controlled is not limited to the horizontal seal unit. For example, the displacement of a cooling unit, a punching unit for drilling, etc. may be controlled in the same manner as described above.

The above-described displacement control method for a bag making machine according to the present invention and the bag making machine 10 to which the displacement control method is applied provide the following effects.
The displacement control method of the present invention uses only two sensors for detecting the reference mark 3: a front mark sensor 32 and a rear mark sensor 33. Therefore, compared to a displacement control method in which, for example, each mark reading sensor is disposed immediately before each processing unit, it is possible to save space for arranging the mark reading sensors and shorten the distance between each processing unit. Therefore, the line length of the bag making machine 10 can be shortened and the installation area can be reduced. This leads to a reduction in fixed costs related to the bag making machine and a reduction in product loss at the start-up of production.

In addition, since the distance DS between the cutting unit 29 related to the displacement control and the rear mark sensor 33 is large (far apart), as a result, the expansion and contraction of the long bag-making film 1 is averaged to a certain extent and reflected in the displacement control. Therefore, even if the printing pitch P varies locally, the effect of the local variation in printing pitch P is unlikely to be felt, and the positional accuracy related to the displacement control of each processing unit can be improved.
Furthermore, in the control method of the present invention, the displacement is preferably controlled every 12 to 60 cycles. Therefore, in view of the actual amount of expansion and contraction of the long bag-making film 1, it is difficult to imagine that the positional deviations of the processing positions in the processing units (21, 24, 25, 26, etc.) will deviate from their respective allowable ranges, and the operating load on each drive unit can be reduced, thereby improving the durability of the drive units.

[Bag manufacturing method]
The bag making machine 10 and the method of controlling the bag making machine 10 according to the present invention have been described above. Next, a method for manufacturing bags manufactured using the bag making machine 10 and its control method according to the present invention will be described.
The bag manufacturing method is a method for manufacturing bags 8 using a bag making machine 10 and its control method, in which a plurality of lateral bags are transported on a long bag making film 1 in which two or more pieces are conveyed in a stacked manner. A horizontal sealing step in which the horizontal sealing is completed by performing heat treatment for horizontal sealing multiple times using the sealing unit (24, 25, 26), and after the horizontal sealing step, the long bag-making film 1 is cut. The bag 8 is cut into individual bags 8 by the unit 29.

As described above, the bag making machine 10 includes a conveying device 11 that intermittently conveys two or more long bag making films 1, at least one of which has a reference mark 3 printed at a constant printing pitch P, in a stacked manner; a plurality of transverse sealing units (24, 25, 26) that are disposed on the conveying path of the long bag making film 1 so as to be displaceable forward and backward in the conveying direction and that perform a heat treatment for transverse sealing on the long bag making film 1 when the long bag making film 1 is stopped; a plurality of processing unit driving devices (34, 35, 36) that individually displace the plurality of transverse sealing units to their respective target positions; and a cutting unit 29 that is disposed at the very front of the conveying path of the long bag making film 1 and cuts the long bag making film. a front mark sensor 32 that is disposed behind the cutting unit 29 in the conveying direction and detects the reference mark 3 to determine the stop position of the long bag making film 1; a rear mark sensor 33 that is disposed in a position where the reference mark can be detected while the long bag making film 1 is conveyed a distance corresponding to the printing pitch P from the stop position of the previous stage and is disposed in a position behind the rearmost horizontal sealing unit (first horizontal sealing unit 24) of the multiple horizontal sealing units (24, 25, 26) in the conveying direction; and a processing unit displacement control means (processing unit displacement control device 31) that individually controls the displacement of the multiple processing unit driving devices (34, 35, 36).

Furthermore, the processing unit displacement control means (processing unit displacement control device 31) stores the transport distance from the stop position of the previous stage until the rear mark sensor 33 detects the reference mark 3 as the reference mark sensor offset distance X, calculates the amount of expansion and contraction within the long bag-making film 1 from the difference between the stored reference mark sensor offset distances X before and after a predetermined period of transport (Xe-Xs), calculates target positions for the multiple lateral sealing units (24, 25, 26) individually based on the amount of expansion and contraction within the apparatus (Xe-Xs), and individually controls the displacement of the multiple processing unit drive devices so that they move to the target positions.
According to the manufacturing method of bag 8 of the present invention, bags 8 can be manufactured while still obtaining the respective effects described above in the bag making machine 10 and the control method for the bag making machine 10 of the present invention.

Although the bag making machine 10, the method of controlling the bag making machine 10, and the method of manufacturing the bag 8 according to the present invention have been described above, the present invention is not limited to the above embodiments. The above-mentioned embodiments are illustrative, and any embodiments that have substantially the same configuration and achieve similar effects to the technical idea stated in the claims of the present invention are not covered by the present invention in any case. within the technical scope of the invention.

The bag making machine 10, the control method for the bag making machine 10, and the manufacturing method for the bag 8 according to the present invention can improve the position adjustment accuracy of the processing unit and reduce product loss at the start-up of production. Therefore, they can be suitably applied when manufacturing packaging bags for food, beverages, medicines, etc.

REFERENCE SIGNS LIST 1 Long bag-making film 2 Raw roll 3 Reference mark 3b Rear mark sensor reference mark 5 Cutting line 8 Bag 10 Bag-making machine 11 Conveying device 12 Conveying control device 13 Nip roll 14 Encoder 24, 25, 26 Horizontal sealing unit 29 Cutting unit 31 Processing unit displacement control device 32 Front mark sensor 33 Rear mark sensor 34, 35, 36, 39 Processing unit driving device P Printing pitch X Reference mark sensor offset distance Xs Reference mark sensor offset distance at start Xe Reference mark sensor offset distance at end

Claims (6)

a conveyance device that intermittently conveys a long bag-making film on which at least reference marks are printed at a constant printing pitch;
Disposed on the conveyance path of the long bag-making film so as to be displaceable forward and backward in the conveyance direction, and performing a predetermined process on the long bag-making film when the long bag-making film is stopped. multiple processing units,
a plurality of processing unit drive devices that individually displace the plurality of processing units to each target position;
a cutting unit that is disposed at the forefront of the conveyance path of the long bag-making film and cuts the long bag-making film into individual pieces;
a front mark sensor that is disposed behind the cutting unit in the conveying direction and determines a stop position of the long bag-making film by detecting the reference mark;
A position where the reference mark can be detected until the long bag-making film is conveyed a distance corresponding to the printing pitch from the previous stop position, and from the rearmost processing unit among the plurality of processing units. a rear mark sensor located at a rear position in the transport direction;
The amount of transport from the stop position of the previous stage until the rear mark sensor detects the reference mark is stored as a reference mark sensor offset distance, and from the difference in the reference mark sensor offset distances stored before and after the predetermined period of transport, The amount of expansion/contraction within the device of the long bag-making film is calculated, the target positions of the plurality of processing units are individually calculated based on the amount of expansion/contraction within the device, and the plurality of processing units are processed so as to be displaced to the target positions. A bag making machine comprising processing unit displacement control means for individually controlling the displacement of unit drive devices. The machining unit displacement control means further includes a presetting means for presetting the plurality of machining units to respective positions before the start of manufacturing,
The machining unit displacement control means has a function of storing the positions of the machining units when the production item and the production item progress,
2. The bag making machine according to claim 1, wherein the presetting means sets each of the positions of the plurality of processing units stored when the same production item was previously produced as each preset position, and controls the displacement of the plurality of processing unit drive devices individually so that the processing units move to each preset position. a conveyance device that intermittently conveys a long bag-making film on which at least reference marks are printed at a constant printing pitch;
Disposed on the conveyance path of the long bag-making film so as to be displaceable forward and backward in the conveyance direction, and performing a predetermined process on the long bag-making film when the long bag-making film is stopped. multiple processing units,
a plurality of processing unit drive devices that individually displace the plurality of processing units to each target position;
a cutting unit that is disposed at the forefront of the conveyance path of the long bag-making film and cuts the long bag-making film into individual pieces;
a front mark sensor that is disposed behind the cutting unit in the conveyance direction and determines a stop position of the long bag-making film by detecting the reference mark;
A position where the reference mark can be detected until the long bag-making film is conveyed a distance corresponding to the printing pitch from the previous stop position, and from the rearmost processing unit among the plurality of processing units. a rear mark sensor located at a rear position in the transport direction;
A bag making machine comprising a processing unit displacement control means,
The processing unit displacement control means stores the amount of transport from the stop position of the previous stage until the rear mark sensor detects the reference mark as a reference mark sensor offset distance, and stores the reference mark stored before and after the predetermined period of transport. Calculate the amount of expansion/contraction of the long bag-making film in the device from the difference in the mark sensor offset distance, calculate the target positions of the plurality of processing units individually based on the amount of expansion/contraction in the device, and set the target position to the target position. A method for controlling a bag making machine, comprising individually controlling the displacement of the plurality of processing unit drive devices so as to cause displacement. The machining unit displacement control means further includes presetting means for presetting the plurality of machining units at respective positions before starting manufacturing,
The processing unit displacement control means has a function of storing a production item and each position of the plurality of processing units when the production item advances,
The presetting means sets each position of the plurality of machining units memorized when the same production item was progressed in the past as each preset position, and individually drives the plurality of machining unit drive devices so as to be displaced to each of the preset positions. The method for controlling a bag making machine according to claim 3, wherein displacement is controlled. A method for manufacturing bags manufactured by a bag making machine, the method comprising:
Reference marks are printed at a constant printing pitch on at least one of the two or more long bag-making films,
The bag making machine is
a conveyance device that stacks and intermittently conveys two or more of the long bag-making films;
Disposed on the conveyance path of the long bag-making film so as to be displaceable forward and backward in the conveying direction, and for horizontally sealing the long bag-making film when the long bag-making film is stopped. Multiple horizontal seal units that perform heat treatment,
a plurality of processing unit drive devices that individually displace the plurality of horizontal seal units to each target position;
a cutting unit that is disposed at the forefront of the conveyance path of the long bag-making film and cuts the long bag-making film;
a front mark sensor that is disposed behind the cutting unit in the conveyance direction and determines a stop position of the long bag-making film by detecting the reference mark;
A horizontal seal at a position where the reference mark can be detected before the long bag-making film is conveyed a distance corresponding to the printing pitch from the previous stop position and at the rearmost of the plurality of horizontal seal units. A rear mark sensor located behind the unit in the transport direction;
processing unit displacement control means for individually controlling displacement of the plurality of processing unit drive devices,
The method for manufacturing the bag includes:
a lateral sealing step of completing lateral sealing by performing heat treatment for lateral sealing multiple times by the plurality of lateral sealing units on the long bag-making film, in which two or more films are conveyed in a stacked manner;
After the horizontal sealing step, at least a cutting step of cutting the long bag-making film into individual pieces by the cutting unit,
The processing unit displacement control means stores the amount of transport from the stop position of the previous stage until the rear mark sensor detects the reference mark as a reference mark sensor offset distance, and stores the reference mark stored before and after the predetermined period of transport. From the difference in the mark sensor offset distance, calculate the amount of expansion/contraction within the device of the long bag-making film, calculate the target positions of the plurality of horizontal seal units individually based on the amount of expansion/contraction within the device, and calculate the target positions of the plurality of horizontal seal units individually. A method of manufacturing a bag, comprising individually controlling the displacement of the plurality of processing unit drive devices so that the plurality of processing unit drive devices are displaced. The processing unit displacement control means further includes presetting means for presetting the plurality of lateral seal units to respective positions before starting manufacturing,
The processing unit displacement control means has a function of storing a production item and each position of the plurality of horizontal seal units when the production item advances,
The presetting means sets each position of the plurality of horizontal seal units stored when the same production item was produced in the past as each preset position, and individually operates the plurality of processing unit driving devices so as to be displaced to each of the preset positions. 6. The bag manufacturing method according to claim 5, wherein displacement is controlled to .