JP2004035038A - Packaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a packaging device to perform heat-welding of a film for improving workability and a finished condition of a commodity. <P>SOLUTION: This packaging device which has a heater 72a to perform the heat-welding of films pressed against each other and packages a commodity pushed on a packaging station with the film comprises a detecting means 8 to detect at least one of the change in the power to be supplied to the heater and the change in the power supplied to the packaging device, and a control means to control the power to one heat seal to be brought closer to a predetermined value by decreasing/increasing the power supply time to the heater 72a according to an increase/decrease in the detected power. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a packaging device for packaging a product pushed up to a packaging station with a film and thermally welding the film.
[0002]
BACKGROUND OF THE INVENTION
Prior to the present application, the applicant of the present invention, as a packaging device of this type, pushes up a product from below a film stretched horizontally in a packaging station, covers the upper surface of the product with the film, and places the film on a pair of left and right sides. After folding the lower surface of the product from the left and right by the left and right folding plates, the rear folding plate arranged below the left and right folding plates further folds the film folded from the left and right forward, and between the front member. A packaging device (Japanese Patent Application No. 2001-396611) has been proposed which is a stretch packaging machine for packaging products by heat sealing the film with the film interposed therebetween.
Electric power is supplied to the heater for performing the heat sealing. When the supply voltage fluctuates, the temperature of the heater fluctuates. When the temperature of the heater fluctuates, the welding state of the film varies, and the film is not sufficiently welded, or the film is melted too much, and the finished state of the product varies.
Therefore, a method in which the operator manually adjusts the ON time of the heater can be considered.
[0003]
[Problems to be solved by the invention]
However, such adjustment is troublesome in itself, increases the burden on the operator, and lowers the workability. In addition, it is necessary to learn operations for adjustment.
Further, it is unavoidable that a delay occurs when the voltage fluctuates, and therefore, the finished state of some products is lowered. As a result, it becomes necessary to repack the product, and there is a problem that the consumption of the film increases.
[0004]
Therefore, an object of the present invention is to improve the workability and the finished state of a product in a packaging apparatus in which films are brought into pressure contact with each other and heated and thermally welded, and to suppress wasteful consumption of films.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a packaging apparatus that includes a heater that welds a film by heat while pressing the films together, and that supplies a product pushed up to a packaging station with the film. Detecting means for detecting at least one of a change in electric power supplied to the packaging apparatus and a change in electric power supplied to the packaging apparatus, and reducing or increasing the power supply time to the heater in accordance with an increase or decrease in the detected value of the electric power. Control means for controlling the amount of electric power for one heat seal to approach a predetermined value.
[0006]
When the electric power supplied to the heater is large, the temperature of the heater rises to a predetermined temperature in a short time. On the other hand, when the electric power supplied to the heater is small, the temperature is raised to the predetermined temperature. take time. Therefore, by detecting the value of the power and shortening the power supply time when the power is large, and increasing the power supply time when the power is small, the power of one heat seal can be obtained regardless of the power value. As the volume approaches a constant value, the temperature of the heater approaches the predetermined temperature.
[0007]
In the present invention, "detecting a change in power" may mean detecting the power itself, but since the resistance value of the heater is constant, at least one of the current value and the voltage is detected. It means what you have to do.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a packaging device according to an embodiment of the present invention will be described with reference to the drawings.
A stretch packaging machine will be described as an example of the packaging device. This stretch wrapping machine is a small-scale weighing and packaging device, and is designed to wrap fruits and vegetables in note trays and wrap foods (products) such as fruits and vegetables stored in soft trays. Packaging is possible even for products placed on foam trays.
In the present embodiment, a case will be described in which a product placed on a tray is packed together with the tray. The stretch wrapping machine has a weighing function and a label making function. The wrapping function will be mainly described.
[0009]
overall structure:
As shown in FIG. 1, the present stretch wrapping machine has various mechanisms attached to a main body frame 2 and mainly includes a product loading device 10 and a lifting means 30.
[0010]
When the product is placed on the product carrying-in device 10 by the operator's hand, the product is weighed by a weighing device (not shown) and then sent to the lift unit 30. On the other hand, as shown in the side sectional view of FIG. 2 and the front sectional view of FIG. 3, the film F conveyed above the lifting means 30 by the film supply device 40 is pre-stretched by a film holding mechanism described later. . When the product (packaged material) M supported by the lifting means 30 is pushed up against the pre-stretched film F, the product M is covered with the film F in an upward and lateral direction in a state where the film F is pushed up. State.
[0011]
Thereafter, as shown in FIG. 4A, first, the left and right films F are placed on the bottom side of the product M by the left and right folding plates 64 and 65. Folded. At the time of this folding operation, the left and right folding plates 64 and 65 enter near the left and right ends of the bottom of the product M and serve to support the bottom of the product M. Thereafter, the front and rear films F are folded into the bottom of the product M by the rear folding plate 71 (see FIGS. 7B and 7C). The film F folded on the bottom side of the product M is sandwiched between the rear folding plate 71 and the front fixing member 72, and is pressed against a heater 72a provided on the front fixing member 72 to fuse the films F together. Thus, heat sealing is performed (see FIG. 7D). Thereafter, the product M is pressed onto the heat sealing means 73 in FIG. 1, whereby the films F folded on the bottom surface side are combined and welded.
[0012]
A label discharged from a pricing mechanism (not shown) is affixed to the product M packaged with the film F including the heat seal by an operator's hand.
[0013]
Film holding mechanism:
The film holding mechanism includes a rear clamp 53 and a front clamp 54 shown in FIG. 2, and left and right clamps 51 and 52 and left and right pushing members 61 and 62 shown in FIG.
The film holding mechanism serves to grip the peripheral edge of the film F when the product M is pushed upward by the lift means 30, and stretches the film F immediately before the film F is pushed up. A pre-stretch operation for setting the state is performed. By this pre-stretching operation, each of the clamps 51 to 54 and the left and right pushing members 61 and 62 gripping the peripheral portion of the film F move horizontally in a direction away from each other, and the film F is stretched by a predetermined amount.
[0014]
Lifting means 30:
As shown in FIGS. 3 and 7, the lift means 30 includes left and right support members 34a for supporting the bottom surface of the product M. The support member 34a is movable in the vertical direction, and lifts the product M to transfer the product M to the packaging station S.
[0015]
Film folding mechanism:
The left and right folding plates 64 and 65 shown in FIG. 3 are arranged above the left and right pushing members 61 and 62 and fold the film F on the left and right sides.
As shown in FIG. 2, the rear folding plate 71 is arranged below the left and right folding plates 64 and 65 and above the left and right pushing members 61 and 62. The rear folding plate 71 folds the film F from the rear to the bottom side of the product M.
[0016]
Heater 72:
The front-side fixing member 72 is fixed to the main body frame 2, and a heater 72 a is provided at the center of the rear end of the front-side fixing member 72 as shown in FIGS. When the rear folding plate 71 folds the film F from the rear side to the bottom side of the product M, as described later, the heater 72a is energized at a predetermined timing, and the rear folding plate 71 is connected to the front fixing member 72. The heat sealing is performed with the film F interposed therebetween.
[0017]
Control configuration:
As shown in FIG. 5, the present stretch wrapping machine includes a microcomputer (control means) 3 for controlling the above-described devices and the like. The microcomputer 3 is connected to a stroke key unit 11, a label printer 12, a touch screen 13, a weighing / packaging value control device 14, a local control device 15, an A / D converter 85, a switch 83, and the like via an interface (not shown). Have been. The A / D converter 85 is provided integrally with the microcomputer 3 chip.
The above-described devices are connected to the local control device 15, and the microcomputer 3 controls the devices.
[0018]
A heater 72 a is connected to the commercial power supply 80 via a transformer 81. A switch 83 and a current sensor 82 are connected in series to the heater 72a and the transformer 81. The transformer 81 is for reducing the voltage of the commercial power supply 80 having a rating of 200 V, for example, and applying a relatively low voltage to the heater 72a.
[0019]
The current sensor 82 is for detecting a change in the value of the current supplied to the heater 72a. That is, when the heater 72a is energized, a current flows through the current sensor 82 due to the induced electromotive force, and the current is half-wave rectified by the diode 86 and then converted by the A / D converter 85 into a detection value I consisting of a digital value. Is input to the microcomputer. A current corresponding to a current value flowing through the heater 72a flows through the current sensor 82. Therefore, the current sensor 82 and the A / D converter 85 and the like detect a change in the current supplied to the heater 72a. 8.
The switch 83 is turned on / off by the microcomputer 3 at a predetermined timing described later, and switches between energization and stop of the heater 72a.
[0020]
The microcomputer 3 includes a CPU 4 and a memory 7. The memory 7 is provided with a timing storage unit 7a. As shown in FIG. 5B, the timing storage unit 7a stores a current value range (information on the detection value I), a power supply stop timing to the heater 72a, and the like in association with each other. ing.
The CPU 4 turns on the switch 83 at a predetermined timing to energize the heater 72a, and then controls the timing of stopping the power supply to the heater 72a according to the detection value I from the A / D converter 85. That is, as described later, the CPU 4 reads the stop timing corresponding to the range of the detection value I from the timing storage unit 7a based on the detection value I from the A / D converter 85, and The switch 83 is turned off to stop the power supply to the heater 72a.
[0021]
Packaging operation:
Next, among the packaging operations of the stretch packaging machine, mainly the folding operation of the film F and the heat sealing operation will be described.
After the operator performs a predetermined operation and starts the packaging machine, when the commodity M is placed on the commodity carrying-in device 10 of FIG. 1, the packaging operation starts.
[0022]
When the film F is conveyed above the lifting means 30 in FIG. 3 by the film supply device 40 in FIG. 2, the left and right ends of the film F are gripped by the left and right pushing members 61 and 62 and the left and right clamps 51 and 52. You. On the other hand, the front and rear ends of the film F are gripped by the front and rear clamps 53 and 54 in FIG.
[0023]
Thereafter, when the film F is pre-stretched, the product M is pushed up by the lifting means 30 with respect to the film F, and the upper surface and the side surface of the product M are covered with the film F. After the pushing up, the left and right folding plates 64 and 65 move inside each other as shown in FIG.
[0024]
Rear folding operation;
After the left and right folding operation, the rear folding plate 71 shown in FIG. 7A starts moving forward, and the rear clamp 53 moves forward with a slight delay so that excessive tension does not act on the film F. I do. On the other hand, the left and right support members 34a are lowered, and the product M is supported by the left and right folding plates 64 and 65.
Thereafter, as shown in FIG. 7B, when the rear folding plate 71 advances, the product M is slid forward on the left and right folding plates 64 and 65 by the tension of the film F.
[0025]
Thereafter, as shown in FIG. 7 (c), the rear folding plate 71 continues to move further forward, and when the commodity M is slid forward on the left and right folding plates 64, 65, the product M is eventually formed. As shown in FIG. 4D and FIG. 4B, the rear folding plate 71 contacts the front fixing member 72, and the heater 72a welds the films F to each other.
Thereafter, the product M is pressed on the heat sealing means 73 (FIG. 1) by the operator.
[0026]
Here, in the wrapping operation, the switch 83 of the heater 72a is turned on T seconds after one wrapping cycle is started, and the heater 72a is supplied with AC power as shown in FIG. Thereafter, a current value flowing through the current sensor 82 is detected until the timing T0. When the detected current value is input to the CPU 4, the CPU 4 reads the timing and the like from the timing storage unit 7a in FIG.
[0027]
For example, when the power supply voltage of the commercial power supply 80 is close to the rating, a current of about 0.9 A to 1.1 A flows, and a current value corresponding thereto is detected. Therefore, when the current value is 0.9 A or more and less than 1.1 A, the timing T2 in FIG. 5B is read, and the switch 83 is opened (OFF) at the normal timing T2 in FIG. ) As a result, a current flows through the heater 72a for a predetermined time t2 as shown in FIG. 6C, and the heater rises to a predetermined temperature.
[0028]
On the other hand, when the voltage of the power supply is higher than the rated value, a current of 1.1 A or more flows, and a current value corresponding to the current is detected. Therefore, when the current value is 1.1 A or more, the timing T1 in FIG. 5B is read, and the switch 83 is opened (OFF) at the timing T1 earlier than the timing T2 in FIG. 6A. . As a result, as shown in FIG. 6B, the power supply time t1 to the heater is shortened, so that even if the voltage is high, the temperature of the heater becomes too high, and it is possible to prevent the film from being excessively heated.
[0029]
On the other hand, when the voltage of the power supply is lower than the rating, and therefore the current value is 0.5 A or more and less than 0.9 A, the timing T3 in FIG. 5B is read out and the timing T2 in FIG. At a later timing T3, the switch 83 is opened (OFF). As a result, as shown in FIG. 6D, the power supply time t3 to the heater becomes longer, so that even if the voltage is low, the temperature of the heater becomes too low, and it is possible to prevent the film from being incompletely welded.
[0030]
Further, when the current value is less than 0.5 A, the CPU 4 determines that the heater 72a is disconnected, and displays on the touch screen 13 or the like that the heater 72a is disconnected.
[0031]
As described above, by changing the power supply time to the heater in accordance with the increase / decrease of the detected value I of the current, the electric energy for one heat seal is controlled so as to approach a predetermined value. Therefore, for example, even if the commercial power supply 80 fluctuates suddenly, the change in the temperature of the heater 72a becomes small, and a stable heat seal state can be obtained.
Further, it is not necessary to adjust the ON time of the heater 72a, and it is not necessary to learn the operation of such adjustment.
[0032]
Further, since the change of the current supplied to the heater 72a is detected by the detecting means 8, even if the resistance value of the heater 72a varies for each packaging device, a stable heat sealing state is obtained. Is obtained.
[0033]
By the way, in the above embodiment, the change in the current value supplied to the heater is detected. However, as shown in FIG. 8, a voltage detecting means 8A is provided to detect the change in the voltage applied to the heater. Is also good. The CPU 4 performs control such that the power supply time to the heater is reduced or increased in accordance with the increase or decrease of the detection value from the voltage detection means 8A so that the power amount for one heat seal approaches a predetermined value. Other configurations are the same as those of the above-described embodiment, and the same or corresponding portions are denoted by the same reference characters, and detailed description and illustration thereof are omitted.
[0034]
As described above, the preferred embodiments have been described with reference to the drawings. However, those skilled in the art will easily envisage various changes and modifications within the obvious scope upon reading this specification.
For example, as the front member, a front folding plate that moves rearward during the film folding operation may be provided. Further, the heater may be provided on the rear folding plate, or may be provided on both the rear folding plate and the front member.
[0035]
Further, the current value or the voltage may be detected between the commercial power supply 80 and the transformer 81. That is, the value of the current or voltage supplied to the packaging device may be detected. In addition, power that is an integrated value of a current value and a voltage may be detected.
[0036]
Further, in the present invention, the power supply time to the heater may be changed, and it is not always necessary to change the heater OFF timing. For example, before power is supplied to the heater, a change in the voltage of the commercial power supply 80 may be detected, the heater ON timing may be changed in accordance with the voltage change, and the heater OFF timing may be constant.
[0037]
Also, there is no need to turn ON / OFF the power supply to the heater when the current value crosses zero.
Further, the power supply time is changed in three steps, but may be changed in two steps, or may be changed in four or more steps. For example, only one threshold value is set, and if the detected value is smaller than the threshold value, the power is supplied only for the time t. On the other hand, if the detected value is larger than the threshold value, the power is supplied for the time t + Δt May be performed.
The power supply time may be controlled by a so-called firing angle. For example, as in Japanese Patent Application Laid-Open No. H11-301833 (Japanese Patent Application No. H10-124034), the temperature control may be performed by changing the power supply time by changing the time for applying a voltage for one cycle of AC. .
Accordingly, such changes and modifications are to be construed as being within the scope of the invention as defined by the appended claims.
[0038]
【The invention's effect】
As described above, according to the present invention, the amount of power for one heat seal is controlled so as to approach a predetermined value by changing the power supply time to the heater. Even if it occurs, the change in the temperature of the heater becomes small, and a stable heat sealing state can be obtained.
Further, it is not necessary to adjust the heater ON time, and it is not necessary to learn the operation of such adjustment.
[0039]
Further, by detecting a change in the current supplied to the heater, it is possible to stabilize the power amount even if the resistance value of the heater for each packaging device varies.
[0040]
Furthermore, since the disconnection of the heater can be detected along with the detection of the current value, there is no need to separately provide a detecting means for detecting the disconnection.
[0041]
If a plurality of power supply stop timings are stored in advance and the stop timings are read out, the present invention can be easily realized by changing software.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a packaging machine of the present invention.
FIG. 2 is a partially cutaway side view of the packaging machine.
FIG. 3 is a front sectional view of the packaging machine.
FIG. 4 is a schematic perspective view showing a main part of the packaging machine.
FIG. 5A is a schematic configuration diagram of the packaging machine, and FIG. 5B is a chart showing storage contents of a storage unit.
FIG. 6 is a diagram showing a relationship between a current value and a stop timing.
FIG. 7 is a process chart showing a packaging and sealing method.
FIG. 8 is a schematic configuration diagram of a packaging machine showing another example.
[Explanation of symbols]
3: microcomputer (control means)
8: detecting means 64, 65: left and right folding plates 71: rear folding plate 72a: heater 82: current sensor (detecting means)
85: A / D converter (detection means)
F: Film M: Product S: Packaging station

Claims (9)

A packaging device that includes a heater that heats the films while the films are pressed against each other and that packages the products pushed up to the packaging station with the films.
Detection means for detecting at least one of a change in power supplied to the heater, or a change in power supplied to the packaging device,
Control means for reducing or increasing the power supply time to the heater in accordance with an increase or decrease in the detected value of the power so as to control the amount of power for one heat seal to approach a predetermined value; . A packaging device that includes a heater that heats the films while the films are pressed against each other and that packages the products pushed up to the packaging station with the films.
Detecting means for detecting at least one of a change in the voltage applied to the heater or a change in the voltage supplied to the packaging device,
Control means for reducing or increasing the power supply time to the heater in accordance with an increase or decrease in the detected value of the voltage, and controlling the amount of power for one heat seal to approach a predetermined value; . A packaging device that includes a heater that heats the films while the films are pressed against each other and that packages the products pushed up to the packaging station with the films.
Detection means for detecting at least one of a change in current supplied to the heater, or a change in current supplied to the packaging device;
Control means for reducing or increasing the power supply time to the heater in accordance with an increase or decrease in the detected value of the current so as to control the amount of power for one heat seal to approach a predetermined value; . In claim 3,
At a timing when the heater should be energized, if the detected value of the current is smaller than a predetermined value, the control unit determines that the heater is disconnected. In any one of claims 1 to 4,
A packaging device, wherein after the power supply to the heater is started at a predetermined timing, the control means controls a stop timing of power supply to the heater in accordance with an output from the detection means. In claim 5,
A packaging device configured to delay the stop timing when the detection value is small. In claim 5,
A packaging apparatus wherein the stop timing is advanced when the detected value is large. In any one of claims 5 to 7,
Further comprising a storage unit that stores information related to the detection value and information related to the stop timing in association with each other,
The packaging device, wherein the control means reads the stop timing according to the detected value and controls so as to stop power supply at the stop timing. In any one of claims 1 to 8,
The packaging device pushes up the product from below the film stretched horizontally to the packaging station, covers the upper surface of the product with the film, and folds the film from the left and right to the lower surface of the product by a pair of left and right folding plates. The rear folding plate disposed below the left and right folding plates further folds the film folded from the left and right forward, and heat seals the film with the film sandwiched between the left and right members to package the product. A packaging device that is a stretch packaging machine.

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