JP6536031B2 - Bag making machine and control method thereof - Google Patents

Description

  According to the present invention, a long bag-making film (generally a plastic film) printed with at least a reference mark (including a print pattern usable as a reference mark) at a constant printing pitch, a length corresponding to the printing pitch The present invention relates to a bag making machine for intermittently transporting bags at a distance (distance) and performing predetermined processing (seal, punch, cut, etc.) on a bag making film in a stopped state to produce a bag, and a control method thereof.

  In the conventional bag making machine, the displacement of the seal position due to the expansion and contraction of the plastic film for bag production, and the displacement due to the slip at the time of conveyance, etc. have been detected visually. Although it is necessary to slightly displace the processing unit for processing the film according to the detected positional displacement amount, this has also been adjusted manually. In particular, in the case of a film on which a pattern is repeatedly printed at a constant pitch, the displacement of the seal position can not be ignored.

  Patent Document 1 discloses a bag making machine that automatically eliminates the problem that the position of the print pattern and the processing position (in particular, the position of the horizontal seal, etc.) shift due to the expansion or contraction of the plastic film.

Patent No. 4819110 gazette

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

  That is, in the bag making machine described in Patent Document 1, the printing pitch is calculated and the displacement amount of the processing unit is determined, but the conveyance error of the plastic film by the bag making machine is not taken into consideration. It does not rise. In addition, the processing unit is driven after the plastic film transfer is stopped, and the production speed can not be increased.

  In the present invention, in the bag-making machine, first, the accuracy of the fine adjustment of the position of the processing unit is enhanced in consideration of the transport error based on the slip of the film for bag production caused by the transport device and the stability of the control device of the transport device. With the goal.

  Another object of the present invention is to increase the production speed of a bag making machine by advancing the start point of the fine adjustment of the processing unit.

  Of course, the present invention can sufficiently cope with the positional variation based on the expansion and contraction of the bag-making film.

  A bag making machine according to the present invention comprises a transport device for intermittently transporting a long bag-making film having at least a reference mark printed at a constant pitch, a transport path for the bag-making film forward and backward in the transport direction. And a processing unit for displacing the processing film to perform a predetermined processing on the film for forming a bag when the film for forming a bag is stopped, and a processing unit drive for displacing the processing unit in an instructed displacement direction. An apparatus, disposed facing the transport path in relation to the processing unit to detect the fiducial mark between the stop position of the previous stage and the transport of the film for bag production from the previous stage stop position; Measured conveyance amount measured by measuring the actual conveyance amount until the mark sensor and the mark sensor detect the reference mark after starting the conveyance from the stopped state of the mark sensor and the previous stage And the remaining transport amount is determined based on the transport target value output from the control device of the transport device, and the displacement direction and the displacement amount of the processing unit are calculated based on the comparison between the remaining transport amount and the reference remaining transport amount. And displacement control means of the processing unit for controlling the processing unit drive device.

  In a preferred embodiment, the displacement control means of the processing unit controls the drive of the processing unit drive device to start before the stop of the next stage of the film for bag production being conveyed.

  According to the control method of the bag making machine according to the present invention, the conveying device for intermittently conveying the long bag making film having at least the reference marks printed at a constant pitch, the conveyance direction of the bag making film facing A processing unit, which is disposed to be displaceable forward and backward and performs predetermined processing on the bag-making film when the bag-making film is at rest, displaces the processing unit in the displacement direction instructed, and displaces the processing unit A processing unit driving device and the transport path in relation to the processing unit so as to detect the fiducial mark while the film for forming a bag is transported from the stop position of the previous stage to a distance corresponding to the constant pitch. In a bag making machine provided with a mark sensor disposed facing to the front, conveyance is started from the stop state of the previous stage, and the actually measured transport from the mark sensor to detection of the reference mark The amount is measured, the remaining transport amount is determined based on the measured actual transport amount measured and the transport target value output from the control device of the transport device, and the processing is performed based on the comparison between the remaining transport amount and the reference remaining transport amount. The displacement direction and the displacement amount of the unit are calculated, and the drive of the processing unit drive device is controlled to start before the stop of the next stage of the film for bag production being conveyed.

  The control device of the transfer apparatus preferably acquires data related to the actual transfer amount every intermittent transfer or every several intermittent transfers, and updates and outputs the transfer target value based on this data.

  According to the present invention, the conveyance of the film is started from the stop state, and the actual conveyance amount until the mark sensor detects the reference mark of the film being conveyed is measured. Then, the remaining transport amount is determined based on the measured actual transport amount measured and the transport target value output from the control device of the transport device, and the displacement direction of the processing unit is compared based on the comparison between the remaining transport amount and the reference remaining transport amount. The displacement amount is calculated, and the displacement of the processing unit is controlled based on the calculated displacement direction and the displacement amount.

  A transport error due to slippage or instability in the transport device is reflected in the transport target value output from the control device of the transport device. Since this transfer target value is used as one parameter for the fine adjustment of the position of the processing unit, the fine adjustment of the position of the processing unit in consideration of the transfer error can be realized, and the accuracy can be enhanced. In addition, the actual transport amount is measured from when the film is started to be transported from the stop position until the mark sensor detects the reference mark, and this actual transport amount is also used as one of the parameters for fine adjustment of the processing unit position. . Since the expansion and contraction of the film are reflected in the measured transport amount, the position adjustment of the processing unit is realized in consideration of the fluctuation of the stop position of the film due to the expansion and contraction of the film. Furthermore, since the displacement drive of the processing unit based on the calculated displacement direction and displacement amount is started before the stop of the next stage of the film, the start point of the fine adjustment of the processing unit is advanced, and the manufacture of higher speed is possible. Bag production becomes possible.

  When a plurality of processing units are disposed along the transport path of the film for bag production, the mark sensor is provided for each of the processing units. The displacement control means of the processing unit calculates the displacement direction and displacement amount of the processing unit based on the detection of the reference mark by the corresponding mark sensor for each of the processing units, and drives the unit of the corresponding processing unit Control the device.

  Thus, the present invention is also applied to the case where there are a plurality of processing units.

  Preferably, the reference remaining transport amount is updated in the displacement control means based on the average value of the remaining transport amounts over an appropriate range after an appropriate number of repetitions as intermittent.

The overall configuration of the bag making machine is shown. The bag making process is shown. (A), (B) and (C) show measurement and calculation methods of various amounts for displacement control of the processing unit. The processing procedure by a control device is shown.

  FIG. 1 is a perspective view showing the outline of the overall configuration of the bag making machine, and FIG. 2 is a plan view showing the bag making process by the bag making machine shown in FIG.

  The bag making machine includes a transport device 10 for intermittently transporting the long bag-making film (or sheet) 1. The conveying device 10 unrolls the original film 1 wound around a roll or the like (not shown) and conveys it in the longitudinal direction. Two sheets of film 1 are stacked, and in this embodiment, they are conveyed in the horizontal plane. In general, the film 1 is a plastic film, and a pattern (including characters) (not shown) is repeatedly printed at a constant pitch (printing pitch). There is a reference mark 2 in a part of this pattern. The reference marks 2 are also provided at the above-mentioned constant pitch, and are used for the conveyance control of the conveyance device 10, the minute displacement control of the processing unit to be described later, and the like.

  A large number (only a part of which is shown) of a pair of upper and lower nip rolls 13 are arranged along the conveyance path (conveyance path) of the conveyance device 10. The pair of upper and lower nip rolls 13 sandwiches and conveys two stacked films 1 therebetween. The nip roll 13 is rotationally driven by a drive device (motor) 12 via, for example, a timing belt. The transport device 10 further includes its control device 11, an encoder 14 and an optical sensor 15. The encoder 14 is mounted, for example, on the rotation axis of the nip roll 13 (or the rotation axis of the motor or the other axis rotating in synchronization therewith), and is used to measure the amount of rotation, ie, the transport amount of the film 1 by the nip roll 13 Be done. An output signal of the encoder 14 is given to the controller 11. The optical sensor 15 detects the fiducial mark 2 printed on the film 1 and is disposed at an appropriate position of the transport path. This optical sensor 15 may be used also as any one of optical sensors 33, 43, 46, 49, 63, 73 described later. The optical sensor 15 outputs a detection signal (for example, a pulse representing the leading end of the reference mark 2 in a rising direction) every time the reference mark 2 passes through the mounting position, and gives it to the control device 11.

  The control device 11 controls the drive motor 12 (and thus the nip roll 13) to intermittently rotate. That is, the conveyance of the film 1 is intermittently repeated, and the film 1 is stopped between the conveyance. In this stop time, processing (seal, punch, cut, etc.) to the film 1 for bag production is performed. The amount of one conveyance of intermittent conveyance by the conveyance device 10 corresponds to the printing pitch, that is, the distance (length) between the adjacent reference marks 2.

  The conveyance control by the control device 11 sets a conveyance target value L (corresponding to the printing pitch), and drives (starts and stops) the motor 12 until the conveyance amount (measured by the output of the encoder 14) reaches this target value. It is something to do. Then, the control device 11 measures the conveyance amount of the intermittent conveyance for one time and the printing pitch measured based on the output of the encoder 14 (conveyed from the generation of the output signal from the optical sensor 15 to the generation of the next output signal , Or the length to be transported is compared, and based on the comparison result, a transport target value L for the next intermittent transport is generated (the transport target value L is updated). If the measured transport amount is smaller than the printing pitch (for example, the next output signal is not generated from the optical sensor 15 even if the intermittent transport is completed), a value slightly larger than the previous transport target value is set to the next transport target Output as value L. Conversely, if the measured transport amount is larger than the printing pitch (the reference mark 2 passes the position of the optical sensor 15), a value slightly smaller than the previous transport target value is output as the next transport target value L Do. The amount by which the transfer target value is increased or decreased is not necessarily a value proportional to the difference between the measured transfer amount and the printing pitch, in order to prevent occurrence of overshoot or a phenomenon in which the transfer target value L increases and decreases frequently. It is preferable to make the value extremely small so that the value gradually increases or decreases. The above-described transport control itself is a known technology. The updated transport target value L is given from the control device 11 to the displacement control device 21 of the processing unit.

  Along the transport path of the transport apparatus 10, from the upstream side (rear in the transport direction; right side in FIGS. 1 and 2) to the downstream (forward in the transport direction; left side in FIGS. 1 and 2); 31, the cooling unit 34, the horizontal seal units 41, 44, 47, the cooling units 51, 52, the punch unit 61, and the cutter unit 71 are arranged in this order. These units are collectively called a processing unit (processing device). Each processing unit is supported so as to be movable (adjustable in position) in a direction along the transport direction (in the front-rear direction). Since processing (seal, cooling, punching, cutting) by these processing units is performed when conveyance of the film 1 being intermittently conveyed is stopped, each processing unit is suitable for processing at the stop position of the film 1 It is placed at a position and is finely adjusted to the optimum position as described later.

  The vertical seal unit 31 is driven by a slight displacement (position adjustment) in a direction (back and forth direction) along the transport direction by a drive device (processing unit drive device) 32 including a motor. Similarly, the horizontal seal units 41, 44 and 47 can be slightly displaced in the forward and backward directions by the drive devices 42, 45 and 48, respectively. The punch unit 61 is slightly displaced by the drive position 62 and the cutter unit 71 is slightly displaced forward or backward in the transport direction by the drive unit 72, respectively.

  Furthermore, the optical sensor 33 is upstream of the vertical seal unit 31, the optical sensors 43, 46, 49 are upstream of the horizontal seal units 41, 44, 47, and the optical sensor 63 is upstream of the punch unit 61. An optical sensor 73 is disposed upstream of the cutter unit 71, respectively. These optical sensors 33, 43, 46, 49, 63, 73 are for detecting the reference mark 2 printed on the film 1 (for example, like the output signal of the optical sensor 15, The timing of detection of the reference mark 2 is made at the rising edge of the output signal).

  The film 1 is intermittently fed by the distance corresponding to the printing pitch as described above. Each of the optical sensors 33, 43, 46, 49, 63, 73 is located between adjacent stop positions so as to detect the reference mark 2 which has reached a position a predetermined distance from the stop position of the previous stage of the film 1 Is preferred). Detection signals of the optical sensors 33, 43, 46, 49, 63, 73 are given to the displacement control device 21 of the processing unit. The displacement control device 21 controls the processing unit drive devices 32, 42 and 45 based on the detection signals from these optical sensors, the transport target value L given from the control device 11 of the transport device 10, and the actual transport amount y described later. , 48, 62, 72 to finely adjust the longitudinal position of the processing units 31, 41, 44, 47, 61, 71 along the transport direction.

  The vertical seal unit 31 heats and fuses (heats) the two side portions of the two-ply film 1 on both sides by the length of one printing pitch (formation of the vertical seal portion 3). The cooling unit 34 cools the welded vertical seal portion 3. The lateral sealing units 41, 44 and 47 heat and fuse the two-layered film 1 in the width direction at intervals of one printing pitch (formation of the lateral sealing portion 4). The same place is heated by these horizontal seal units 41, 44, 47. The cooling units 51 and 52 cool the lateral seal portion 4. The punch unit 61 forms cuts (notches for opening the bag) 6 at two positions substantially at the center of the transverse seal portion 4. The cutting unit 73 cuts the transverse seal 4 along its center line (cut line 7). The film 1 may be cut at the center line (cut line 8) in the width direction by the cutting unit 73, or may be cut along the cut line 8 by a cutter (not shown) disposed further downstream. Good. In this way, from the two-layered film 1, two bags sealed at three sides are produced for each printing pitch.

  Control of each unit drive device, that is, fine adjustment of each processing unit is performed as follows.

  FIG. 3 shows a state in which the intermittently made film 1 for bag manufacturing is intermittently transported. FIG. 3A shows a state in which the transport is stopped. One of the fiducial marks 2 at each printing pitch is denoted by 2A for convenience of explanation. The stop position of the printing pitch including the reference mark 2A is clearly shown as the previous (previous) stop position particularly in FIG. 3A (the center position is indicated by an arrow). At the stop position, the film is processed by the processing device.

  The state of the moment when the reference mark 2A is detected by the optical sensor 33 (rise of the output signal of the optical sensor 33) is shown in FIG. 3 (B) when the conveyance of the film 1 starts from the state of FIG. There is. The film 1 continues to be transported. The amount (length, distance) by which the film 1 is conveyed while the conveyance is started from the front stage stop position and the reference mark 2A is detected by the optical sensor 33 is taken as the actually-measured conveyance amount y. The actual transport amount y is measured by the controller 11 or the displacement controller 21 based on the output signal of the encoder 14. The output signal of the encoder 14 may be directly input to the displacement control device 21. Preferably, the installation position of the optical sensor 33 is determined so that the actually-measured conveyance amount y becomes about half (before and after) the conveyance target value L.

  The displacement control device 21 calculates the remaining transport amount x by the following equation (Equation (1)) based on the transport target value L given from the transport control device 11 and the measured transport amount y measured.

      x = L−y .. Formula (1)

  The remaining transport amount x indicates how long the transport device 10 should transport the film 1 by a distance (length) corresponding to the transport target value L.

  Further, the displacement control device 21 finely adjusts the position of the processing unit (vertical seal unit 31) according to the following equation (equation (2)) using a given reference remaining transport amount xo and the above remaining transport amount x. The displacement amount Δx is calculated.

      Δx = x−xo .. Formula (2)

  The initial value of the reference remaining transport amount xo is determined on the basis of a standard printing pitch (printing pitch on a film without expansion and contraction), the setting stop position of the film, and the installation position of the optical sensor. After operation of the bag making machine, the standard remaining transport amount xo is updated by the average value of the remaining transport amount x of 10 to 50 times before and after every 100 to 1000 intermittent transports.

  The calculated displacement amount Δx is used for fine adjustment of the position of the processing unit (vertical seal unit 31) associated with the optical sensor 33 (paired with the optical sensor 33). If Δx is positive (x> xo), the film portion (printed pattern) for the printing pitch slightly goes to the downstream side, so the processing unit is located on the downstream side in the transport direction as the absolute value of Δx Move the displacement amount equivalent to. Conversely, if .DELTA.x is negative (x <xo), the processing unit is moved upstream by a displacement amount corresponding to the absolute value of .DELTA.x. The displacement of the processing unit is carried out under the control of the control device 21 by means of the corresponding drive (drive 32 in the case of the vertical sealing unit 31). In this manner, the film is processed by the processing unit at a position matching the printing pitch regardless of the expansion and contraction of the film 1 and the conveyance error by the conveyance control device 11.

  FIG. 3C shows a state in which the film is stopped again after being transported by the transport amount corresponding to the transport target value L from the stop state (FIG. 3A). Processing is also performed on the film at this stop position. What is important is the remaining transport distance x and displacement from the detection of the reference mark 2A by the optical sensor 33 (Fig. 3 (B)) to the stop of the film next time (next step) (Fig. 3 (C)). The calculation of the quantity Δx and the start of the displacement drive of the processing unit by the drive are taking place. The displacement drive of the processing unit may end after the film has stopped (FIG. 3C). Of course, film processing is performed after fine adjustment of the processing unit is completed.

  As described above, the control device 11 of the transfer device updates the transfer target value L for each intermittent transfer. This is to correct the transport error based on slip and the transport error based on transport control instability. For that purpose, it may happen that the printing pitch of the film (the position of the printing pattern including the reference mark 2) slightly differs from the position of the processing device. By finely adjusting the position of the processing unit, this is corrected so that processing is always applied to the portion where the processing unit matches the printing pitch of the film. As described above, when the transport target value L becomes large (for the sake of simplicity, the measured transport amount y is constant), the printing pitch (reference mark 2) of the film will be excessive, so the processing unit is also downstream Move it to a very small amount. Conversely, when the transport target value L decreases, the printing pitch (reference mark 2) does not reach the position of the processing unit, so the position of the processing unit is moved upstream.

  In addition, it can cope with the expansion and contraction of the film. For example, when the film stretches, the actual transport amount y increases (the transport target value L is constant for simplicity) and the remaining transport amount x decreases, so the processing unit is moved upstream ( Although it is a slight displacement amount). Conversely, when the film is shrunk, the measured transport amount y decreases and the remaining transport amount x increases, so the processing unit is moved downstream.

  Furthermore, since the calculation based on the equations (1) and (2) is performed from the time when the optical sensor detects the reference mark, and the fine adjustment of the processing unit position is started based on the result (film transport stops Compared to the case where the drive of the processing unit drive device has been started before) and the movement of the processing unit is started after the transport of the film is stopped, it is possible to realize rapid bag-making.

  Based on the detection signal of an optical sensor located in the vicinity of the processing unit, preferably at the nearest upstream position (preferably within one printing pitch, may be about 2 printing pitches), with the processing unit and the optical sensor being paired Since the above calculation is performed, partial expansion and contraction of the film can be dealt with. Depending on the size of the processing unit, it is also possible to arrange the processing unit and the optical sensor within one printing pitch.

  FIG. 4 shows a control processing procedure by the control devices 11 and 21. S11, S16, and S18 are processes by the control device 11 of the transfer apparatus, and the remaining processes are processes by the displacement control device 21. The processing by the displacement controller 21 is performed separately for each pair of optical sensor and processing device.

  The film transport is started from the state in which the transport is stopped (FIGS. 3A and 3C) (S11). When the detection signal from the optical sensor is input (S12), the remaining transport amount x is calculated for each combination of the processing unit and the optical sensor (S12), and the displacement amount Δx of each processing unit is calculated. The displacement direction is determined (S14), and driving of the drive device of each processing unit is started based on the result (S15).

  Then, when the conveyance of the conveyance target value L ends from the conveyance start (S11), the conveyance of the film is stopped (S16), and the processing by each processing unit is started (S17). The processes of S11 to S17 are repeated until there is no film wound on the roll (S18).

1 Film for bag production 2, 2A Reference mark 3 Longitudinal seal portion 4 Horizontal seal portion 6 Cut 7, 8 Cut line
10 Transport device
11 Control device of transport device
14 encoder
21 Displacement control device
31 Vertical seal unit (processing unit)
32, 42, 45, 48, 62, 72 Drive unit
33, 43, 46, 49, 63, 73 Optical sensor
34, 51, 52 Cooling unit
41, 44, 47 horizontal seal unit
61 Punch unit
71 cutter unit

Claims (7)

A conveying device for intermittently conveying a long bag-making film on which at least a reference mark is printed at a constant pitch,
A processing unit that is disposed displaceably forward and backward in the transport direction facing the transport path of the bag-making film, and performs predetermined processing on the bag-making film when the bag-making film is stopped,
A processing unit drive device for displacing the processing unit in the displacement direction indicated by the displacement amount,
A mark disposed facing the transport path in relation to the processing unit so as to detect the fiducial mark while the bag-making film is transported from the previous stop position to the distance equivalent to the constant pitch Sensor and transport start from the stop state of the previous stage, measure the actual transport amount y until the mark sensor detects the reference mark, and measure the actual transport amount y measured and transport output from the control device of the transport device Based on the target value L , the remaining transport amount x is calculated by L-y, and the displacement direction and displacement amount of the processing unit are calculated based on the comparison between the remaining transport amount x and the reference remaining transport amount x _o Control means of the processing unit for controlling the processing unit drive device,
Making machine equipped with The displacement control means of the processing unit controls the driving of the processing unit drive device to start before the stop of the next stage of the film for film production being conveyed.
The bag making machine according to claim 1. Including a plurality of processing units disposed along the transport path of the bagging film,
The mark sensor is provided for each processing unit,
The displacement control means of the processing unit calculates the displacement direction and the displacement amount of the processing unit based on the detection of the reference mark by the corresponding mark sensor for each of the processing units. To control,
The bag making machine according to claim 1 or 2.   The bag manufacturing machine according to any one of claims 1 to 3, wherein the displacement control means of the processing unit updates the reference remaining transport amount based on the average value of the remaining transport amounts.   The bag manufacturing method according to any one of claims 1 to 4, wherein the control device of the transfer device acquires data related to an actual transfer amount, and outputs a transfer target value based on the data. Machine. A conveying device for intermittently conveying a long bag-making film on which at least a reference mark is printed at a constant pitch,
A processing unit that is disposed displaceably forward and backward in the transport direction facing the transport path of the bag-making film, and performs predetermined processing on the bag-making film when the bag-making film is stopped,
A processing unit drive device for displacing and displacing the processing unit in the instructed displacement direction, and the reference mark during the time the film for bag making is conveyed from the stop position of the previous stage to a distance corresponding to the constant pitch In a bag making machine provided with a mark sensor arranged facing the transport path in relation to the processing unit to detect,
The actual conveyance amount y from when the previous stage stop state is started to when the mark sensor detects the reference mark is measured, and the measured actual conveyance amount y measured and the conveyance target value L output from the control device of the conveyance device Based on the above , the remaining transport amount x is obtained by the calculation of L−y , and this remaining transport amount x and the reference remaining transport amount x _o The displacement direction and displacement amount of the processing unit are calculated based on the comparison with the above, and the drive of the processing unit drive device is controlled to start before the stop of the next stage of the film for bag production being conveyed. ,
Control method of bag making machine. In a bag making machine including a plurality of processing units disposed along a transport path of a film for bag production, and a mark sensor being provided for each of the processing units,
The displacement direction and displacement amount of the processing unit are calculated based on the detection of the reference mark of the corresponding mark sensor for each of the processing units, and the unit drive device of the corresponding processing unit is controlled.
The control method of the bag making machine of Claim 6.

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