JP2016117229A - Bag making machine and control method thereof - Google Patents

Abstract

PURPOSE: To provide a bag making machine capable of increasing the accuracy of the position fine adjustment of a processing unit and a production speed in view of a conveyance error.CONSTITUTION: The bag making machine for intermittently conveying a long bag-making film (1) having at least a reference mark (2) printed thereon at a fixed pitch is characterized in that film conveyance is started from the stop state of a last stage, an actual conveyance amount (y) is measured until mark sensors (33, 43, 46, 49, 63, and 73) detect the reference mark, a remaining conveyance amount (x) is obtained based on the measured actual conveyance amount and a conveyance target value (L) output from the controller of a conveyance device, the displacing directions and the displacing amounts of processing units (31, 41, 44, 47, 61, and 71) are calculated based on the comparison of the residual conveyance amount (x) with a reference remaining conveyance amount (xo), and control is carried out to start driving of processing unit driving devices (32, 42, 45, 48, 62, and 72) before the stop of the conveyed bag-making film at a next stage.SELECTED DRAWING: Figure 1

Description

  According to the present invention, a long bag-making film (generally a plastic film) on which at least a reference mark (including a printed pattern that can be used as a reference mark) is printed at a fixed printing pitch is used for a length corresponding to the printing pitch. The present invention relates to a bag making machine that intermittently conveys (distance) at a time and applies predetermined processing (seal, punch, cut, etc.) to a bag making film in a stopped state, and a control method thereof.

  In a conventional bag making machine, a shift in the sealing position due to expansion and contraction of the plastic film for bag making and a positional shift due to slippage during conveyance have been detected visually. Although it is necessary to slightly displace the processing unit that processes the film according to the detected positional deviation, this was also manually adjusted. In particular, in the case of a film on which a pattern is repeatedly printed at a constant pitch, the deviation of the seal position cannot be ignored.

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

Japanese Patent No. 4819110

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

  In other words, in the bag making machine described in Patent Document 1, the printing pitch is calculated and the displacement of the processing unit is determined, but the plastic film transport error by the bag making machine is not taken into account, and the adjustment accuracy is It will not rise. In addition, since the processing unit is driven after the plastic film is stopped, the production speed cannot be increased.

  In the bag making machine, first, the accuracy of fine adjustment of the position of the processing unit is improved in consideration of the conveyance error based on the slip of the bag making film caused by the conveyance device and the stability of the control device of the conveyance device. With the goal.

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

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

  The bag-making machine according to the present invention has a conveying device for intermittently conveying a long bag-making film on which at least a reference mark is printed at a constant pitch, facing the conveyance path of the bag-making film, and forward and backward in the conveying direction. A processing unit that displaces the bag-making film and applies the predetermined processing to the bag-making film when the bag-making film is stopped, and a processing unit drive that displaces the processing unit in the indicated displacement direction. The apparatus and the bag-making film are arranged so as to face the conveyance path in relation to the processing unit so that the reference mark is detected from the stop position in the previous stage until the film is conveyed a distance corresponding to the fixed pitch. Mark sensor, and the actual measured transport amount from the previous stop state until the mark sensor detects the reference mark. The remaining transport amount is obtained 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 the displacement control means of the process unit which controls the said process unit drive device is provided.

  In a preferred embodiment, the displacement control means of the processing unit controls the driving of the processing unit drive device before the stop of the next stage of the bag-making film to be conveyed.

  The control method of the bag making machine according to the present invention is such that a conveying device that intermittently conveys a long bag-making film on which at least a reference mark is printed at a constant pitch, a conveyance direction of the bag-making film, Displaceable forward and backward, a processing unit that performs predetermined processing on the bag-making film when the bag-making film is stopped, and displaces the processing unit in the instructed displacement direction. The processing unit drive device and the transport path in relation to the processing unit so as to detect the reference mark until the bag-making film is transported a distance corresponding to the fixed pitch from the preceding stop position. In a bag-making machine equipped with a mark sensor arranged in front of the machine, actual conveyance is started until the mark sensor detects a reference mark, starting conveyance from the previous stop state. The remaining conveyance amount is obtained based on the measured actual conveyance amount and the conveyance target value output from the control device of the conveyance device, and the processing is performed based on the comparison between the remaining conveyance amount and the reference remaining conveyance amount. The displacement direction and displacement amount of the unit are calculated, and control is performed so that the processing unit driving device starts to be driven before the next stage of the bag-making film to be conveyed is stopped.

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

  According to this invention, the conveyance of the film is started from the stop state, and the actually measured conveyance amount from when the mark sensor detects the reference mark of the conveyed film is measured. Then, the remaining conveyance amount is obtained based on the measured actual conveyance amount and the conveyance target value output from the control device of the conveyance device, and the displacement direction of the machining unit is determined based on the comparison between the remaining conveyance amount and the reference remaining conveyance amount. The displacement of the machining unit is controlled based on the calculated displacement direction and displacement.

  A transport error due to slippage or instability in the transport device is reflected in a transport target value output from the control device of the transport device. Since this conveyance target value is used as one parameter for fine adjustment of the position of the machining unit, fine adjustment of the position of the machining unit in consideration of conveyance errors can be realized and the accuracy can be improved. Also, the actual transport amount from the stop position to the start of film transport until the mark sensor detects the reference mark is measured, and this actual transport amount is also used as one of the parameters for fine adjustment of the processing unit position. . Since the measured transport amount reflects the expansion and contraction of the film, fine adjustment of the position of the processing unit is realized in consideration of the change in 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 production speed is increased. Bag production is possible.

  When a plurality of processing units are arranged along the conveyance path of the bag-making film, the mark sensor is provided for each processing unit. The displacement control means of the machining unit calculates a displacement direction and a displacement amount of the machining unit based on detection of a reference mark by the corresponding mark sensor for each machining unit, and unit drive of the corresponding machining unit. Control the device.

  In this way, the present invention is applied even when there are a plurality of processing units.

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

The whole structure of a bag making machine is shown. The bag making process is shown. (A), (B), and (C) show the measurement and calculation methods for various quantities for displacement control of the machining unit. The processing procedure by a control apparatus is shown.

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

  The bag making machine includes a conveying device 10 that intermittently conveys a long bag-making film (or sheet) 1. The transport device 10 unwinds and transports the raw film 1 wound around a roll or the like (not shown) in the longitudinal direction thereof. Two films 1 are stacked, and in this embodiment, the film 1 is conveyed in a horizontal plane. Generally, 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 fixed pitch, and are used for transport control of the transport device 10, minute displacement control of a processing unit described later, and the like.

  A large number of upper and lower nip rolls 13 (only part of which are shown) are arranged along the transport path (transport path) of the transport apparatus 10. The pair of upper and lower nip rolls 13 conveys two stacked films 1 sandwiched between them. The nip roll 13 is rotationally driven by a driving device (motor) 12 through, for example, a timing belt. The transport device 10 further includes a control device 11, an encoder 14, and an optical sensor 15. The encoder 14 is attached to, for example, a rotating shaft of the nip roll 13 (or a rotating shaft of a motor, or another shaft that rotates in synchronization with this), and is used to measure the amount of rotation, that is, the amount of film 1 transported by the nip roll 13. Is done. The output signal of the encoder 14 is given to the control device 11. The optical sensor 15 detects the fiducial mark 2 printed on the film 1 and is disposed at a proper position in the transport path. This optical sensor 15 may also be used as any one of optical sensors 33, 43, 46, 49, 63, and 73 described later. The optical sensor 15 outputs a detection signal (for example, a pulse representing the leading end of the reference mark 2 as a rising edge) 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 hence the nip roll 13) to rotate and drive intermittently. That is, the conveyance of the film 1 is repeated intermittently, and the film 1 stops between the conveyance. During this stop time, processing (seal, punch, cut, etc.) on the film 1 for bag production is performed. A single conveyance amount of intermittent conveyance by the conveyance device 10 corresponds to a printing pitch, that is, a distance (length) between adjacent reference marks 2.

  The conveyance control by the control device 11 sets the 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. Is what you do. Then, the control device 11 conveys the amount of intermittent conveyance for one time measured based on the output of the encoder 14 and the printing pitch (from when the output signal is generated from the optical sensor 15 until the next output signal is generated). Or a length that will be transported), 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 when the intermittent transport is completed), a value slightly larger than the previous transport target value is set as the next transport target. Output as value L. Conversely, if the measured transport amount is larger than the print 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. To do. The amount by which the conveyance target value is increased or decreased is not necessarily a value proportional to the difference between the measured conveyance amount and the print pitch in order to prevent occurrence of overshoot or a phenomenon in which the conveyance target value L frequently increases or decreases. It is preferable that the value be very small so that the value gradually increases or decreases gradually. The conveyance control itself is a known technique. The updated conveyance target value L is given from the control device 11 to the displacement control device 21 of the machining unit.

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

  The vertical seal unit 31 is driven by a slight displacement (position adjustment) in a direction along the conveyance direction (in the front-rear direction) by a drive device (processing unit drive device) 32 including a motor. Similarly, the lateral seal units 41, 44, 47 can be slightly displaced in the forward and backward directions by the driving devices 42, 45, 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 by the drive device 72, respectively.

  Further, an optical sensor 33 is provided upstream of the vertical seal unit 31, an optical sensor 43, 46, 49 is provided upstream of the horizontal seal units 41, 44, 47, and an optical sensor 63 is provided upstream of the punch unit 61. , Optical sensors 73 are arranged on the upstream side of the cutter unit 71, respectively. These optical sensors 33, 43, 46, 49, 63, 73 detect the reference mark 2 printed on the film 1 (for example, in the same manner as the output signal of the optical sensor 15, The reference mark 2 is detected at the rising edge of the output signal).

  The film 1 is intermittently fed by a distance corresponding to the printing pitch as described above. Each optical sensor 33, 43, 46, 49, 63, 73 detects between the adjacent stop positions (substantially intermediate) so as to detect the reference mark 2 that has reached a predetermined distance from the previous stop position of the film 1. Is preferred). Detection signals from the optical sensors 33, 43, 46, 49, 63, 73 are given to the displacement control device 21 of the machining unit. Based on the detection signals from these optical sensors, the conveyance target value L given from the control device 11 of the conveyance device 10 and the measured conveyance amount y, which will be described later, the displacement control device 21 drives each processing unit drive device 32, 42, 45. , 48, 62, 72 are controlled to finely adjust the front and rear positions of the processing units 31, 41, 44, 47, 61, 71 along the conveying direction.

  The vertical seal unit 31 heats and welds both side portions of the two-layer film 1 by a length corresponding to one printing pitch (formation of the vertical seal portion 3). The cooling unit 34 cools the fused vertical seal portion 3. The horizontal seal units 41, 44 and 47 heat and fuse the two stacked films 1 in the width direction at intervals of one printing pitch (formation of the horizontal seal portion 4). The same place is heated by these horizontal seal units 41, 44, 47. The cooling units 51 and 52 cool the horizontal seal portion 4. The punch unit 61 is formed with two cuts (bag opening notches) 6 at substantially the center of the lateral seal portion 4. The cut unit 73 cuts the horizontal seal portion 4 along its center line (cut line 7). The film 1 may be cut along the center line (cut line 8) in the width direction by the cut unit 73, or may be cut along the cut line 8 by a cutter (not shown) arranged on the downstream side. Good. In this manner, two bags with three sides sealed are produced from the two stacked films 1 for each printing pitch.

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

  FIG. 3 shows a state where the intermittently fed bag-making film 1 is intermittently conveyed. FIG. 3A shows a state where the conveyance is stopped. One of the reference marks 2 for each printing pitch is denoted by reference numeral 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 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 film 1 is transported from the state of FIG. 3A and the reference mark 2A is detected by the optical sensor 33 (the rise of the output signal of the optical sensor 33) is shown in FIG. Yes. The film 1 continues to be conveyed. The amount (length, distance) by which the film 1 is transported from the previous stop position until the reference mark 2A is detected by the optical sensor 33 is defined as the actually measured transport amount y. The actually measured transport amount y is measured by the control device 11 or the displacement control device 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 transport amount y is about half of the transport target value L (before and after).

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

      x = L−y Equation (1)

  The remaining conveyance amount x indicates how much longer the length (conveyance amount) should be conveyed in order for the conveyance device 10 to convey the film 1 by a distance (length) corresponding to the conveyance target value L.

  Further, the displacement control device 21 uses the given reference remaining conveyance amount xo and the remaining conveyance amount x to finely adjust the position of the machining unit (vertical seal unit 31) according to the following equation (Equation (2)). A displacement amount Δx is calculated.

      Δx = x−xo Equation (2)

  The initial value of the reference remaining conveyance amount xo is determined based on a standard printing pitch (printing pitch in a film without stretching), a setting stop position of the film, and an installation position of the optical sensor. After operation of the bag making machine, the reference 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 intermittent transport of about 100 to 1000 times.

  The calculated displacement amount Δx is used for fine adjustment of the position of the processing unit (vertical seal unit 31) related to the optical sensor 33 (a pair with the optical sensor 33). When Δx is positive (x> xo), the film portion (print pattern) corresponding to the printing pitch moves slightly more downstream, so the processing unit is moved downstream in the transport direction, and the absolute value of Δx. Move the displacement corresponding to. Conversely, when Δx is negative (x <xo), the machining unit is moved upstream by a displacement corresponding to the absolute value of Δx. The displacement of the machining unit is performed by the corresponding drive device (drive device 32 in the case of the vertical seal unit 31) under the control of the control device 21. In this way, the film is processed by the processing unit at a position matching the printing pitch regardless of the expansion / contraction of the film 1 or the conveyance error by the conveyance control device 11.

  FIG. 3C shows a state where the film is stopped again after the film is conveyed by the conveyance amount corresponding to the conveyance target value L from the stopped state (FIG. 3A). Even at this stop position, the film is processed. What is important is that the remaining transport amount x and displacement are detected between the detection of the reference mark 2A by the optical sensor 33 (FIG. 3 (B)) and the next (next stage) film stop (FIG. 3 (C)). The calculation of the quantity Δx and the start of the displacement drive of the machining unit by the driving device are performed. The displacement drive of the processing unit may end after the film stops (FIG. 3C). Of course, the film is processed after the fine adjustment of the processing unit is completed.

  As described above, the control device 11 of the transport apparatus updates the transport target value L for each intermittent transport. This is to correct a transport error based on slip and a transport error based on instability of transport control. For this reason, the print pitch of the film (the position of the printed pattern including the reference mark 2) may slightly differ from the position of the processing apparatus. This is corrected by fine adjustment of the position of the processing unit, so that the processing unit is always subjected to processing where it matches the print pitch of the film. As described above, when the conveyance target value L becomes large (for the sake of simplicity, the actually measured conveyance amount y is constant), the film printing pitch (reference mark 2) will be excessive, so that the processing unit is also on the downstream side. To (though very little). On the contrary, when the conveyance target value L becomes small, the printing pitch (reference mark 2) does not reach the position of the machining unit, so the position of the machining unit is moved upstream.

  It can also cope with film expansion and contraction. For example, when the film is stretched, the actually measured transport amount y increases (for the sake of simplicity, the transport target value L is constant) and the remaining transport amount x decreases, so that the processing unit is moved upstream ( Although it is a slight amount of displacement). Conversely, when the film shrinks, the actually 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 formulas (1) and (2) is performed from the time when the optical sensor detects the fiducial mark, and the fine adjustment of the position of the processing unit is started based on the result (the film transport stops) Compared with the case where the processing unit driving device has been started before the movement of the processing unit is started after the film transport is stopped, the bag can be made more quickly.

  A processing unit and an optical sensor are paired, and based on a detection signal of an optical sensor arranged in the vicinity of the processing unit, preferably the nearest position upstream (preferably within one printing pitch, or may be about two printing pitches). Therefore, it is possible to cope with partial expansion and contraction of the film. Depending on the size of the processing unit, it is 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 processing by the control device 11 of the transport device, and the rest are processing by the displacement control device 21. The processing by the displacement control device 21 is performed separately for each pair of optical sensor and processing device that make a pair.

  The conveyance of the film is started from the state where the conveyance is stopped (FIGS. 3A and 3C) (S11). When a detection signal from the optical sensor is input (S12), the remaining conveyance amount x is calculated for each set of processing units and optical sensors (S12), and further, the displacement amount Δx of each processing unit is calculated. The displacement direction is determined (S14), and based on the result, driving of the driving device of each processing unit is started (S15).

  When the conveyance of the conveyance target value L is completed 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 making 2,2A Reference mark 3 Vertical seal part 4 Horizontal seal part 6 Notch 7, 8 Cut line
10 Transport device
11 Conveyor control 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 transport device for intermittently transporting a long bag-making film on which at least a reference mark is printed at a constant pitch;
A processing unit that is disposed so as to be displaceable forward and backward in the transport direction, facing the transport path of the bag-making film, and that performs predetermined processing on the bag-making film when the bag-making film is stopped,
A machining unit driving device for displacing and displacing the machining unit in a designated displacement direction;
A mark arranged facing the transport path in relation to the processing unit so as to detect the reference mark during the period from when the bag-making film is transported a distance corresponding to the fixed pitch from the stop position in the preceding stage. Measure the actual transport amount from the sensor and the previous stop state until the mark sensor detects the reference mark, measure the actual transport amount and the transport target value output from the control device of the transport device The displacement of the machining unit that controls the machining unit driving device by calculating the displacement direction and the displacement amount of the machining unit based on the comparison between the remaining conveyance amount and the reference remaining conveyance amount. Control means,
A bag making machine. The displacement control means of the processing unit controls the driving of the processing unit driving device to start before the stop of the next stage of the bag-making film to be conveyed.
The bag making machine according to claim 1. Including a plurality of processing units arranged along the conveyance path of the bag-making film,
The mark sensor is provided for each processing unit,
The displacement control means of the machining unit calculates a displacement direction and a displacement amount of the machining unit based on detection of a reference mark by the corresponding mark sensor for each machining unit, and provides a unit drive device for the corresponding machining unit. To control,
The bag making machine according to claim 1 or 2.   The bag making 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 an average value of the remaining transport amount.   5. The bag making according to claim 1, wherein the control device of the transport device acquires data related to an actual transport amount and outputs a transport target value based on the data. Machine. A transport device for intermittently transporting a long bag-making film on which at least a reference mark is printed at a constant pitch;
A processing unit that is disposed so as to be displaceable forward and backward in the transport direction, facing the transport path of the bag-making film, and that performs predetermined processing on the bag-making film when the bag-making film is stopped,
The processing unit driving device for moving the processing unit in the instructed displacement direction, the processing unit driving device, and the reference mark between the stop position of the previous stage and the transport of the reference mark by the distance corresponding to the fixed pitch. In a bag making machine provided with a mark sensor arranged facing the conveyance path in relation to the processing unit,
The conveyance is started from the previous stop state, the actual conveyance amount from when the mark sensor detects the reference mark is measured, and based on the measured actual conveyance amount and the conveyance target value output from the control device of the conveyance device Obtain the remaining transport amount, calculate the displacement direction and displacement amount of the processing unit based on the comparison between the remaining transport amount and the reference remaining transport amount, and before stopping the next stage of the film for bag making to be transported , Control to start driving of the machining unit driving device,
Control method of bag making machine. In a bag making machine including a plurality of processing units arranged along a conveyance path of a bag forming film, wherein a mark sensor is provided for each processing unit,
For each of the processing units, a displacement direction and a displacement amount of the processing unit are calculated based on detection of a reference mark of the corresponding mark sensor, and a unit driving device of the corresponding processing unit is controlled.
The method for controlling a bag making machine according to claim 6.

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