JP7497015B2 - Packaging Machine - Google Patents

Description

The present invention relates to a packaging machine that, for example, wraps newspapers in film.

A wrapping machine that wraps newspapers in film typically sandwiches the newspaper between two rolls of film, then heat-welds the film around the newspaper. The film is then cut at the heat-welded area, and the machine waits for the next newspaper to be inserted. The film roll is freely rotatable, and rotates when the film is pulled out and stops when the pull is stopped.

The moment of inertia of a roll when rotating differs depending on the remaining length of the film, i.e., the size of the roll diameter. A roll with a larger diameter is heavier than a roll with a smaller diameter, and requires more time for the rotation speed to stabilize after rotation starts, and more time from when braking begins to when it stops.

Japanese Patent Application Laid-Open No. 8-143008

It is known that in the above-mentioned type of packaging machine, the length of film pulled out from the two rolls differs by at least the thickness of the newspapers. When a difference occurs in the length of film pulled out from the two rolls, the amount of film consumed differs, and the roll diameter of the two rolls also differs. Furthermore, this difference in roll diameter gradually increases as the number of newspapers to be packaged increases. As a result, the replacement times for the two rolls differ, and the packaging machine must always be operated with the roll diameters different.

As mentioned above, if the diameters of the two rolls are different, the time it takes for the rolls to rotate and stop will differ, causing variations in the slack in the film. As a result, the sealing position of the film (welded part) will shift from the center position facing the edge of the newspaper, and wrinkles will appear in the film, making the packaged product in which the newspaper is wrapped in film look bad.

The present invention has been made in consideration of the above points, and aims to provide a packaging machine that can improve the appearance of packaged products.

One aspect of the packaging machine of the present invention includes a conveying mechanism that clamps and restrains a stack having an item to be packaged sandwiched between a first packaging material pulled out from a first roll and a second packaging material pulled out from a second roll, conveys the stack in the pulling-out direction of the first and second packaging materials, and stops the stack at a predetermined position, a first detection unit that detects the pulling-out length of the first packaging material, a second detection unit that detects the pulling-out length of the second packaging material, and a bonding unit that bonds and cuts the first packaging material and the second packaging material upstream in the pulling-out direction from a rear end of the stack stopped at the predetermined position by the conveying mechanism in the pulling-out direction of the item to be packaged. The device has a cutting unit, a first braking unit that stops rotation of the first roll, a second braking unit that stops rotation of the second roll, and a control unit that detects the pull-out lengths of the first and second packaging materials from when the conveying mechanism starts conveying the laminate to when it stops at a predetermined position via the first and second detection units, and after stopping the laminate at the predetermined position, controls the first and second braking units so that the timing of stopping the roll wrapped with the packaging material with the shorter pull-out length is delayed compared to the timing of stopping the roll wrapped with the packaging material with the longer pull-out length .

According to one aspect of the present invention, a packaging machine can be provided that can improve the appearance of packaged products.

FIG. 1 is a schematic diagram showing a packaging machine according to an embodiment of the present invention. FIG. 2 is a block diagram of a control system for controlling the operation of the packaging machine of FIG. FIG. 3 is a timing chart for explaining the operation timing of the packaging machine of FIG. FIG. 4 is a diagram showing an example of a data table used for controlling the operation of the packaging machine of FIG.

Hereinafter, a packaging machine 10 according to an embodiment of the present invention will be described with reference to the drawings.
Fig. 1 is a schematic diagram for explaining the structure of the packaging machine 10. Fig. 2 is a block diagram of a control system for controlling the operation of the packaging machine 10. Fig. 3 is a timing chart for explaining the operation timing of the packaging machine 10. Fig. 4 is a diagram showing an example of a data table used for controlling the operation of the packaging machine 10.

As shown in FIG. 1, the packaging machine 10 has a housing 1 equipped with an inlet 1a for inserting newspaper P, which is an article to be packaged, and an outlet 1b for ejecting packaged product W (not shown) in which newspaper P is packaged with films F1 and F2. The housing 1 is formed in a substantially rectangular box shape, with a top wall 1c above in the direction of gravity and a bottom wall 1d below in the direction of gravity. The inlet 1a extends in a direction perpendicular to the paper surface in FIG. 1 and is provided on the top wall 1c, and the outlet 1b extends in a direction perpendicular to the paper surface in FIG. 1 and is provided on the bottom wall 1d. In this embodiment, newspaper P, which is a folded stack of multiple newspapers, is used as an example of the article to be packaged, but the article to be packaged is not limited to newspaper P and may be other items such as booklets or flat boxes.

The packaging machine 10 has a roll R1 (first roll) with a long resin film F1 (first packaging material) wound around shaft S1, and a roll R2 (second roll) with a long resin film F2 (second packaging material) wound around shaft S2. Shafts S1 and S2 extend in a direction perpendicular to the paper surface in FIG. 1, and are positioned at positions spaced apart from each other by a distance that does not cause the rolls R1 and R2 to interfere with each other. Both ends of shafts S1 and S2 are each rotatably supported with respect to housing 1, and rolls R1 and R2 are each freely rotatable. Rolls R1 and R2 are also attached to housing 1 in an interchangeable manner.

In Figure 1, roll R1 on the left side is attached inside housing 1 in a position that rotates clockwise when film F1 is pulled out. Roll R2 on the right side is attached inside housing 1 in a position that rotates counterclockwise when film F2 is pulled out. Rolls R1 and R2 rotate when films F1 and F2 are pulled out, and even after the pulling of films F1 and F2 is stopped, rolls R1 and R2 tend to continue rotating for a while due to inertia.

Two guide rollers 2a and 2b are provided downstream of the inlet 1a along the insertion direction of the newspaper P. The insertion direction of the newspaper P is the direction of gravity from top to bottom in FIG. 1, and this direction may be referred to as the pull-out direction below. The guide rollers 2a and 2b wrap the films F1 and F2 pulled out from the rolls R1 and R2 around them and guide them downward in FIG. 1. The guide rollers 2a and 2b have axes extending in a direction perpendicular to the paper surface in FIG. 1. The guide rollers 2a and 2b are arranged near the inlet 1a, spaced apart from each other on the left and right at an interval that is larger than the thickness of the newspaper P and slightly wider than the width of the inlet 1a. The films F1 and F2 guided through the gap between the guide rollers 2a and 2b are pulled out in the direction of gravity. The newspaper P inserted into the housing 1 through the inlet 1a is passed between the two films F1 and F2.

Downstream of the guide rollers 2a, 2b along the pull-out direction of the films F1, F2, guide plates 3a, 3b are provided, extending approximately parallel to the pull-out direction. In FIG. 1, the left guide plate 3a is disposed facing the rear side opposite the surface of the film F1 facing the passage for the newspapers P, and the right guide plate 3b is disposed facing the rear side opposite the surface of the film F2 facing the passage for the newspapers P. The guide plates 3a, 3b function to direct the leading ends of the films F1, F2 in the pull-out direction between the cutter 4a and heater 4b of the adhesive cutting section 4, and to suppress fluttering of the films F1, F2.

Further downstream of the guide plates 3a, 3b along the pull-out direction of the films F1, F2, there is provided an adhesive cutting section 4 that adhesively bonds and cuts the two films F1, F2. The adhesive cutting section 4 has a cutter 4a with a blade extending in a direction perpendicular to the paper surface in FIG. 1, and a heater 4b that extends in the same direction as the blade of the cutter 4a. The cutter 4a is disposed on the rear side of the film F2 on the right side of the figure, and the heater 4b is disposed on the rear side of the film F1 on the left side. The heater 4b has a groove that receives the blade of the cutter 4a. The cutter 4a and heater 4b have a length that exceeds at least the width of the films F1, F2.

When the cutter 4a is moved leftward from the position shown in the figure toward the heater 4b, the two films F1 and F2 are sandwiched between the cutter 4a and the heater 4b and come into contact with each other, and the two films F1 and F2 are welded together by the heat of the heater 4b. At the same time, the welded portions of the films F1 and F2 are cut by the cutter 4a at approximately the center position in the pull-out direction. As a result, the rear ends in the pull-out direction of the two films F1 and F2 that have passed through the adhesive cutting section 4 are welded together, and the leading ends in the pull-out direction of the two films F1 and F2 upstream of the adhesive cutting section 4 along the pull-out direction are welded together.

A sensor 5 for detecting the passage of the newspaper P is provided upstream of the adhesive cutting section 4 along the pull-out direction of the films F1 and F2 and downstream of the guide plates 3a and 3b. A sensor 6 for detecting the passage of the newspaper P is provided downstream of the adhesive cutting section 4 along the pull-out direction of the films F1 and F2. The sensors 5 and 6 are each a transmission type photoelectric sensor having a light emitting element and a light receiving element on both the left and right sides of the transport path of the newspaper P. In other words, the sensor 5 is disposed at a position where its light beam crosses the transport path of the newspaper P upstream of the adhesive cutting section 4, and the sensor 6 is disposed at a position where its light beam crosses the transport path of the newspaper P downstream of the adhesive cutting section 4. The light beams of the sensors 5 and 6 pass through the films F1 and F2, so that the passage of the newspaper P sandwiched between the films F1 and F2 can be detected. The sensors 5 and 6 may be a reflection type photoelectric sensor that detects the light reflected by the newspaper P.

Further downstream of the sensor 6 along the pull-out direction of the films F1 and F2, a transport mechanism 8 is disposed which clamps and restrains the stack T, which is made up of two films F1 and F2 and a newspaper P, and transports it in the pull-out direction. The transport mechanism 8 has transport units 8L and 8R of approximately the same structure on both the left and right sides of the stack T as shown. The transport unit 8L on the left side of the figure has a structure in which an endless transport belt 8c is wound around a drive roller 8a and a driven roller 8b that are spaced apart from each other in the direction of gravity. The rotation axes of the drive roller 8a and the driven roller 8b extend in a direction perpendicular to the paper surface. The transport unit 8L is disposed at a position where the transport belt 8c runs in contact with the surface of the stack T on the left side of the figure (the back surface of the film F1).

The conveying unit 8R on the right side of the figure is disposed on the opposite side of the laminate T from the conveying unit 8L, in a position where the conveying belt 8c runs in contact with the surface of the laminate T on the right side of the figure (the back surface of the film F2). This conveying unit 8R may be connected to the drive shaft of the conveying unit 8L via a pulley or timing belt (not shown), and is driven in synchronization with the conveying unit 8L. The conveying belt 8c of the conveying unit 8L runs in a clockwise direction in FIG. 1, and the conveying belt 8c of the conveying unit 8R runs in a counterclockwise direction. The packaged product W conveyed through the conveying mechanism 8 and packaged with the films F1 and F2 is discharged from the packaging machine 10 through the discharge port 1b of the housing 1 by driving the conveying mechanism 8 again after it has been stopped.

As shown in FIG. 2, the packaging machine 10 has a control unit 20 that controls the operation of each unit.
Encoders 11a and 11b for detecting the amounts of films F1 and F2 pulled out from the two rolls R1 and R2, respectively, are connected to the control unit 20. The encoder 11a for detecting the amount of film F1 pulled out functions as a first detection unit, and the encoder 11b for detecting the amount of film F2 pulled out functions as a second detection unit.

Encoders 11a and 11b are attached to the rotation shafts of rollers 9a and 9b (Fig. 1) that are arranged so that their outer circumferential surfaces are in contact with the outer circumferential surfaces of rolls R1 and R2 and can be driven to rotate. Roller 9a functions as a first roller, and roller 9b functions as a second roller. Rollers 9a and 9b also function as support members that support rolls R1 and R2 from below. In other words, both ends of each of rolls R1 and R2 are supported on their shafts S1 and S2 so that they can move up and down relative to the housing 1, and are pressed against the corresponding rollers 9a and 9b by their own weight.

Encoders 11a and 11b have, for example, disks (not shown) fixed to the rotation shafts of rollers 9a and 9b, respectively. Encoders 11a and 11b detect multiple notches provided around the entire circumference of each disk using photoelectric sensors (not shown), and output pulse signals when the notches intermittently block the optical axis. In other words, encoders 11a and 11b output the amount of films F1 and F2 pulled out from rolls R1 and R2 as the number of pulses.

The control unit 20 is also connected to brakes 12a and 12b that stop the rotation of the two rolls R1 and R2, respectively. The brake 12a that stops the rotation of one roll R1 functions as a first braking unit, and the brake 12b that stops the rotation of the other roll R2 functions as a second braking unit. The brakes 12a and 12b each include brake shoes 13a and 13b that press against the rotation shafts of the rollers 9a and 9b to stop the rotation by friction, and actuators 14a and 14b that press the brake shoes 13a and 13b against the rotation shafts of the rollers 9a and 9b. When the brakes 12a and 12b are operated to stop the rotation of the rollers 9a and 9b, the rotation of the rolls R1 and R2 that are in contact with the outer circumferential surfaces of the rollers 9a and 9b is also stopped.

The control unit 20 is also connected to an actuator 15 that drives the cutter 4a of the adhesive cutting unit 4 toward the heater 4b. The control unit 20 is also connected to a power supply device 17 that energizes the heater 4b of the adhesive cutting unit 4 and the side heater 16. The side heater 16 seals both widthwise edges of the two films F1 and F2. The control unit 20 is also connected to a motor 18 that rotates the drive roller 8a of the conveying mechanism 8. The control unit 20 is also connected to a memory unit 19 that stores the operating program of the packaging machine 10 and stores the data table shown in FIG. 4. The memory unit 19 temporarily stores the number of pulses detected via each of the encoders 11a and 11b.

The processing operation using the packaging machine 10 described above will be described below, mainly with reference to Figures 3 and 4.

(preparation work)
First, an operator opens a cover (not shown) of the packaging machine 10, attaches the rolls R1 and R2 to predetermined positions in the housing 1, and pulls out the films F1 and F2 from the rolls R1 and R2. The operator then slackens the films F1 and F2 pulled out from the rolls R1 and R2 above the guide rollers 2a and 2b and overlaps them with each other. After that, the operator closes the cover and turns on the power of the packaging machine 10.

(Preprocessing)
After the above-mentioned (preparatory work), when a worker inserts a newspaper P for pre-processing through the insertion port 1a, the films F1, F2 stacked above the guide rollers 2a, 2b are pushed downward by the leading edge of the newspaper P in the insertion direction (hereinafter simply referred to as the leading edge). The newspaper P thus inserted is sent into the conveying mechanism 8 together with the films F1, F2 due to its own weight. At this time, the control unit 20 monitors the output of the sensors 5, 6, and drives the motor 18 when the leading edge of the newspaper P in the insertion direction interrupts the light beam of the sensor 5 (timing t1 in FIG. 3), causing the conveying mechanism 8 to start operating.

The newspaper P is fed into the transport mechanism 8 with films F1 and F2 stacked on both sides (here, this state is referred to as the laminate T) and is sent between the two transport units 8L and 8R, where it begins to be transported while being sandwiched and restrained between a pair of moving transport belts 8c. In this way, when the transport mechanism 8 begins to transport the laminate T, the films F1 and F2 are also pulled downward by the transport mechanism 8 together with the newspaper P.

When the transport mechanism 8 starts transporting the laminate T, if the films F1 and F2 stacked during the above-mentioned (preparatory work) are slack on the upstream side of the transport mechanism 8, the slack parts of the films F1 and F2 are transported first, and after the slack is gone, the films F1 and F2 are newly pulled out from the rolls R1 and R2. When the transport mechanism 8 starts transporting the laminate T, if there is no slack in the films F1 and F2 on the upstream side of the transport mechanism 8, the films F1 and F2 are pulled out from the rolls R1 and R2, and the rolls R1 and R2 are rotated.

After the transport mechanism 8 starts transporting the stack T, the control unit 20 starts counting the number of pulses output from each of the encoders 11a and 11b when the sensor 6 detects the leading edge of the newspaper P included in the stack T (timing t2). The control unit 20 then stops counting the number of pulses when the sensor 6 detects the trailing edge of the newspaper P in the insertion direction (hereinafter simply referred to as the trailing edge) (timing t3), and writes the number of pulses counted via each of the encoders 11a and 11b between timing t2 and timing t3 into the memory unit 19.

The control unit 20 also stops the motor 18 at the time (t3) when the rear end of the newspaper P is detected by the sensor 6, and stops the transport of the laminate T by the transport mechanism 8. In this state, the laminate T is clamped and restrained by the pair of transport belts 8c and stopped at a predetermined position. On the other hand, if the films F1 and F2 have been pulled out from the rolls R1 and R2 while the laminate T is being transported by the transport mechanism 8, the rolls R1 and R2 will continue to rotate due to their inertia even after the laminate T has been stopped, and the films F1 and F2 will be sent out from the rolls R1 and R2 until the rolls R1 and R2 stop. Here, for ease of explanation, it is assumed that the rolls R1 and R2 are rotating at the time the laminate T is stopped.

After the transport mechanism 8 transports the laminate T and stops it at a predetermined position (t3), the control unit 20 activates the brakes 12a and 12b at a predetermined timing. That is, after stopping the drive of the motor 18, the control unit 20 calculates the difference between the pulse numbers of the encoders 11a and 11b written in the memory unit 19, and obtains the corresponding brake timing from the data table shown in FIG. 4 that is pre-stored in the memory unit 19. The control unit 20 then activates the brakes 12a and 12b at the obtained timing to stop the rolls R1 and R2.

For example, if the number of pulses detected via encoder 11a is 20 pulses less than the number of pulses detected via encoder 11b, the timing to stop roll R1 is delayed by 10 msec from the timing to stop roll R2. Also, if the number of pulses detected via encoder 11b is 8 pulses less than the number of pulses detected via encoder 11a, the timing to stop roll R2 is delayed by 5 msec from the timing to stop roll R1.

In other words, in this embodiment, the timing for stopping the roll with a smaller amount of film pulled out during transport of the laminate T is set to be later than the timing for stopping the roll with a larger amount of film pulled out. Also, in this embodiment, the time for shifting the timing for stopping the rolls R1 and R2 is changed depending on the difference in the amount of film F1 and F2 pulled out. This makes it possible to control the slack of the films F1 and F2 to approximately the same amount upstream of the transport mechanism 8 after the laminate T is stopped. Note that the data table in FIG. 4 is an example, and may be prepared as appropriate according to the model of the packaging machine 10, customer requests, etc.

After stopping the laminate T and the rolls R1 and R2, the control unit 20 operates the cutter 4a of the adhesive cutting unit 4 to weld and cut the two films F1 and F2. At this time, the slack lengths of the two films F1 and F2 are aligned upstream of the transport mechanism 8, so that the slack lengths of the two films F1 and F2 can be made the same on both the upstream and downstream sides of the adhesive cutting unit 4.

Furthermore, after this, the control unit 20 drives the motor 18 to resume the transport of the stack T by the transport mechanism 8, and discharges it through the discharge port 1b. The stack T discharged in this manner has the films F1 and F2 not welded at the leading end of the newspaper P and is open. Therefore, the worker takes out only the newspaper P from the discharged stack T and submits it for reprocessing.

On the other hand, after the pre-processing laminate T is discharged, as described above, the films F1 and F2 upstream of the adhesive cutting section 4 are slack at approximately the same length, and the downstream ends of the films F1 and F2 in the pulling direction are welded together. Therefore, the welded portions of the films F1 and F2 are positioned between the adhesive cutting section 4 and the conveying mechanism 8 without shifting to the left or right. In this state, the packaging machine 10 is in a standby state, waiting for the newspaper P to be inserted as the packaged item.

For ease of understanding, it is assumed here that the rolls R1 and R2 are rotating at the time when the transport of the laminate T by the transport mechanism 8 is stopped (timing t3). However, if the films F1 and F2 overlapped above the guide rollers 2a and 2b in the above-mentioned (preparatory work) are significantly loose, at least one of the rolls R1 and R2 may not be rotating at the time when the laminate T is stopped (t3). In other words, in this case, only the loosened portion of the film is pulled into the transport mechanism 8 by the transport of the laminate T, and no new film is pulled out from the rolls R1 and/or R2 on which the film is wound, and the rolls remain stopped.

If both rolls R1, R2 are stopped when the laminate T is stopped, the number of pulses of the encoders 11a, 11b stored in the memory unit 19 will both be zero. In this case, it is highly likely that both films F1, F2 are slack on the upstream side of the transport mechanism 8. Also, if one of the rolls R1, R2 is stopped when the laminate T is stopped, only the number of pulses detected via the encoder attached to the stopped roll will be zero. In this case, too, it is highly likely that the film being pulled out from the stopped roll is slack on the upstream side of the transport mechanism 8, and the film being pulled out from the rotating roll will become increasingly slack until the roll stops.

In other words, even if at least one of the pulse counts detected via the two encoders 11a, 11b between the start and stop of transport of the laminate T by the transport mechanism 8 is zero, there is a high possibility that slack has formed in the films F1, F2 upstream of the transport mechanism 8. Therefore, in this case, after the films F1, F2 are welded and cut at the adhesive cutting section 4, slack remains in the films F1, F2 upstream of the cutting position, and the welded portions are positioned between the adhesive cutting section 4 and the transport mechanism 8 without shifting left or right.

However, at the time when the transport of the laminate T by the transport mechanism 8 is stopped, it is possible, in extremely rare cases, for the films F1 and F2 to not become slack on the upstream side of the transport mechanism 8. In other words, this corresponds to the case where the slack in the film that was present on the upstream side of the transport mechanism 8 when the transport of the laminate T began is eliminated exactly at the time the transport of the laminate T is stopped. In this case, the film becomes taut when the laminate T is stopped, and if the film is welded and cut in this state, the film on the upstream side of the adhesive cutting section 4 is likely to become taut, which may have a negative effect on the subsequent packaging process of the newspaper P and may result in a poor appearance of the packaged product W.

Therefore, in this embodiment, before calculating the difference in the number of pulses detected via the two encoders 11a, 11b between the start and stop of the transport of the laminate T by the transport mechanism 8, the control unit 20 determines whether or not at least one of the pulse numbers is zero, and if at least one of the pulse numbers is zero, controls the brakes 12a, 12b so that the rolls R1, R2 stop 40 msec after the transport of the laminate T is stopped.

For example, if the number of pulses detected through encoder 11a is zero and the number of pulses detected through the other encoder 11b is not zero when the transport of the laminate T is stopped, the film F2 can be slackened more by delaying the timing of stopping the rotation of roll R2 by 40 msec. As a result, after the films F1 and F2 are welded and cut at the adhesive cutting section 4 while the film F1 is still in a taut state, the tautness of the film F1 can be relieved by the slackness of the other film F2, and the adverse effects on the subsequent packaging process of the newspaper P can be reduced.

(Wrapping operation)
After the above-mentioned (pre-processing), when a worker inserts a newspaper P as an article to be packaged through the insertion port 1a, the leading edge of the newspaper P pushes the welded portions of the two films F1, F2 downward. The newspaper P thus inserted is sent into the conveying mechanism 8 together with the films F1, F2 due to its own weight. At this time, the control unit 20 monitors the output of the sensors 5, 6, and drives the motor 18 to start the operation of the conveying mechanism 8 when the leading edge of the newspaper P in the insertion direction interrupts the light beam of the sensor 5 (timing t1 in FIG. 3).

The newspaper P fed into the transport mechanism 8 is fed between the two transport units 8L, 8R with films F1, F2 superimposed on both sides, and transport begins while it is sandwiched and restrained between a pair of moving transport belts 8c. In this way, when transport of the laminate T begins by the transport mechanism 8, the films F1, F2 are also pulled downward by the transport mechanism 8 together with the newspaper P. Then, as the laminate T is transported, the films F1, F2 are pulled out from the respective rolls R1, R2, and the rolls R1, R2 rotate.

After the transport mechanism 8 starts transporting the stack T, the control unit 20 starts counting the number of pulses output from each of the encoders 11a and 11b when the sensor 6 detects the leading edge of the newspaper P included in the stack T (timing t2). The control unit 20 then stops counting the number of pulses when the sensor 6 detects the trailing edge of the newspaper P (timing t3), and writes the number of pulses counted via each of the encoders 11a and 11b between timing t2 and timing t3 into the memory unit 19.

The control unit 20 also stops the motor 18 at the time (t3) when the rear end of the newspaper P is detected by the sensor 6, and stops the transport of the laminate T by the transport mechanism 8. In this state, the laminate T is clamped and restrained by the pair of transport belts 8c and stopped at a predetermined position. Meanwhile, the rolls R1 and R2 from which the films F1 and F2 were pulled out while the laminate T was being transported by the transport mechanism 8 continue to rotate due to their inertia, even after the laminate T has been stopped. In other words, after the laminate T has been stopped, the films F1 and F2 are sent out from the rolls R1 and R2 until the rolls R1 and R2 stop.

After the transport mechanism 8 transports the laminate T and stops it at a predetermined position (t3), the control unit 20 activates the brakes 12a and 12b at a predetermined timing. That is, after stopping the drive of the motor 18, the control unit 20 calculates the difference between the pulse numbers of the encoders 11a and 11b written in the memory unit 19, and obtains the corresponding brake timing from the data table shown in FIG. 4 that is pre-stored in the memory unit 19. The control unit 20 then activates the brakes 12a and 12b at the obtained timing to stop the rolls R1 and R2.

For example, if the number of pulses detected via encoder 11a is 20 pulses less than the number of pulses detected via encoder 11b, the timing to stop roll R1 is delayed by 10 msec from the timing to stop roll R2. Also, if the number of pulses detected via encoder 11b is 8 pulses less than the number of pulses detected via encoder 11a, the timing to stop roll R2 is delayed by 5 msec from the timing to stop roll R1.

In other words, in this embodiment, the timing for stopping the roll with a smaller amount of film pulled out during transport of the laminate T is set to be later than the timing for stopping the roll with a larger amount of film pulled out. Also, in this embodiment, the time for shifting the timing for stopping the rolls R1 and R2 is changed depending on the difference in the amount of film F1 and F2 pulled out. This makes it possible to control the slack of the films F1 and F2 to approximately the same amount upstream of the transport mechanism 8 after the laminate T is stopped.

After stopping the laminate T and the rolls R1 and R2, the control unit 20 operates the cutter 4a of the adhesive cutting unit 4 to weld and cut the two films F1 and F2, whose slack lengths have been made uniform upstream of the conveying mechanism 8. After this, the control unit 20 further drives the motor 18 to resume conveying the laminate T by the conveying mechanism 8, and discharges the packaged product W (not shown) through the discharge port 1b.

On the other hand , after the laminate T is discharged, the films F1, F2 on the upstream side of the adhesive cutting section 4 are slackened to approximately the same length, and the downstream ends of the films F1, F2 in the pulling direction are welded to each other. Therefore, the welded portions of the films F1, F2 are positioned between the adhesive cutting section 4 and the conveying mechanism 8 without shifting to the left or right. In this state, the packaging machine 10 is in a standby state, waiting for the next newspaper P to be inserted.

The packaging machine 10 repeats the above operations to package multiple copies of newspapers P with films F1 and F2.

As described above, according to this embodiment, even when the packaging machine 10 is operated with the rolls R1 and R2 having different diameters, the slack in the films F1 and F2 can be uniformly controlled, improving the appearance of the packaged product W.

The present invention has been described above based on the embodiments, but the present invention is not limited to the above-mentioned embodiments, and various modifications and applications are possible within the scope of the gist of the present invention.

For example, in the above embodiment, the conveyance of the laminate T by the conveying mechanism 8 is stopped and the rolls R1 and R2 are stopped at an appropriate time, and then the cutter 4a of the adhesive cutting unit 4 is operated to weld and cut the films F1 and F2, but this is not limited to the above, and the adhesive cutting unit 4 may be operated at a timing after the conveyance of the laminate T is stopped and before the rolls R1 and R2 are stopped. Even in this case, slack can be generated in the films F1 and F2 at least upstream of the adhesive cutting unit 4, and deterioration of packaging quality can be suppressed.

In the above embodiment, the stop timing of rolls R1 and R2 is controlled in stages by referring to a data table prepared in advance. However, the present invention is not limited to this. Rolls R1 and R2 may be stopped at a timing when the difference in the amount of film F1 and F2 pulled out from rolls R1 and R2 between the start and stop of transport of laminate T by transport mechanism 8 becomes zero.

In the above embodiment, the number of pulses is counted via the encoders 11a and 11b to control the stop of the rolls R1 and R2. However, this is not limited to the above. For example, the pull-out speed of the films F1 and F2 pulled out from the rolls R1 and R2 per unit time may be detected to control the stop of the rolls R1 and R2.

Furthermore, in the above-described embodiment, a vertical conveying type packaging machine 10 has been described in which an inlet 1a is provided in the top wall 1c of the housing 1 and an outlet 1b is provided in the bottom wall 1d. However, the present invention is not limited to this and can also be applied to a horizontal conveying type packaging machine in which an inlet 1a is provided in one side wall of the housing 1 and an outlet 1b is provided in the opposing other side wall.
The invention as described in the claims of the present application as originally filed is set forth below.
[1]
a conveying mechanism that clamps and holds a laminate having an article sandwiched between a first packaging material pulled out from a first roll and a second packaging material pulled out from a second roll, conveys the laminate in a direction in which the first and second packaging materials are pulled out, and stops the laminate at a predetermined position;
A first detection unit that detects an amount of the first packaging material being pulled out;
A second detection unit that detects the amount of the second packaging material being pulled out;
a bonding and cutting section that bonds and cuts the first packaging material and the second packaging material upstream in the pulling-out direction from a rear end of the packaged item of the stack stopped at the predetermined position by the conveying mechanism;
a first braking portion that stops rotation of the first roll;
a second braking portion that stops rotation of the second roll;
a control unit that detects, via the first and second detection units, the amounts of the first and second packaging materials pulled out from the time when the transport mechanism starts transporting the stack until the stack is stopped at the predetermined position, and that controls the first and second braking units so that, after the stack is stopped at the predetermined position, the timing of stopping the roll wound with the packaging material pulled out less is delayed compared to the timing of stopping the roll wound with the packaging material pulled out more;
A packaging machine having
[2]
the control unit stops the first and second rolls at a timing when a difference between the amounts of the first and second packaging materials pulled out from the first and second rolls during a period from when the conveyance mechanism starts conveying the laminate to when the conveyance mechanism stops conveying the laminate at the predetermined position becomes zero.
[1] Packaging machine.
[3]
the control unit operates the first and second braking units at a timing when the slack of the first and second packaging materials becomes the same on the upstream side of the conveying mechanism along the pulling-out direction.
[1] Packaging machine.
[4]
the control unit operates the first and second braking units at a timing when the slack of the first and second packaging materials becomes equal upstream of the adhesive cutting unit along the unwinding direction.
[1] Packaging machine.
[5]
The first detection unit detects a rotation amount of a first roller that rotates along with the first roll,
The second detection unit detects a rotation amount of a second roller that rotates along with the second roll.
Any of the packaging machines [1] to [4].

1...Housing, 2a, 2b...Guide rollers, 3a, 3b...Guide plates, 4...Adhesive cutting section, 4a...Cutter, 4b...Heater, 5, 6...Sensor, 8...Transport mechanism, 9a, 9b...Roller, 10...Packaging machine, 11a, 11b...Encoder, 12a, 12b...Brake, 20...Control section, F1, F2...Film, P...Newspaper, R1, R2...Roll, T...Laminate.

Claims (5)

a conveying mechanism that clamps and holds a laminate having an article sandwiched between a first packaging material pulled out from a first roll and a second packaging material pulled out from a second roll, conveys the laminate in a direction in which the first and second packaging materials are pulled out, and stops the laminate at a predetermined position;
a first detection unit that detects a length of the first packaging material being pulled out;
A second detection unit that detects the unwrapped length of the second packaging material;
a bonding and cutting section that bonds and cuts the first packaging material and the second packaging material upstream in the pulling-out direction from a rear end of the packaged item of the stack stopped at the predetermined position by the conveying mechanism;
a first braking portion that stops rotation of the first roll;
a second braking portion that stops rotation of the second roll;
a control unit that detects, via the first and second detection units, the pull-out lengths of the first and second packaging materials from when the conveying mechanism starts conveying the stack until when the stack is stopped at the predetermined position, and that controls the first and second braking units so that, after the stack is stopped at the predetermined position, the timing of stopping the roll wound with the packaging material having the shorter pull-out length is delayed compared to the timing of stopping the roll wound with the packaging material having the longer pull - out length ;
A packaging machine having the control unit stops the first and second rolls at a timing when a difference in pull-out length of the first and second packaging materials pulled out from the first and second rolls during a period from when the conveyance mechanism starts conveying the laminate to when the conveyance mechanism stops conveying the laminate at the predetermined position becomes zero.
2. The packaging machine of claim 1. the control unit operates the first and second braking units at a timing when the slack of the first and second packaging materials becomes the same on the upstream side of the conveying mechanism along the pulling-out direction.
2. The packaging machine of claim 1. the control unit operates the first and second braking units at a timing when the slack of the first and second packaging materials becomes the same upstream of the adhesive cutting unit along the unwinding direction.
2. The packaging machine of claim 1. The first detection unit detects a rotation amount of a first roller that rotates along with the first roll,
The second detection unit detects a rotation amount of a second roller that rotates along with the second roll.
A packaging machine according to any one of claims 1 to 4.