JP2001294210A - Method and apparatus for top seal type packaging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging apparatus wherewith packaging by heat sealing a stretch film to a tray is carried out finely with appearances after packaging is made neat and troubles during conveyance is minimized. SOLUTION: The packaging apparatus 1 covers an opening of a tray T for which the upside is opened with a stretch film Fm, sticks the stretch film to a flange of the tray T by heat sealing and cuts the stretch film by fusing. The packaging apparatus 1 comprises a stretching mechanism 9, a control part and a film take-up part 53. The stretching mechanism 9 stretches the stretch film Fm. The control part makes the stretching mechanism start on working at least before the stretch film is heat sealed to the tray T and controls works for stretching the stretch film Fm. The film take-up part 53 takes up the stretch film Fm after the stretch film is cut by fusing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a top-seal type packaging apparatus and a top-seal type packaging method, and more particularly, to covering an opening of a tray with a stretch film, and welding the stretch film to a portion around the opening of the tray by heat. The present invention relates to a top seal type packaging apparatus that melts and a top seal type packaging method.

[0002]

2. Description of the Related Art Conventionally, an overlap method has been often used as a packaging method for fresh foods such as meat and fish, and processed foods such as side dishes. The overlap method is a method in which a package is placed on a tray and then the entire tray is wrapped with a film.

[0003] However, in the case of the overlap system, the tray and the whole package must be wrapped, and the film must be stacked for sealing.
A film several times as large as the planar size of the tray is required. Also, stack the film on the bottom of the tray,
Sealing is often performed by pressing the bottom of the tray against a hot plate, resulting in poor sealing performance.

[0004] On the other hand, a method of bringing the film only to the opening of the tray whose upper surface is open and welding the film around the opening of the tray (hereinafter referred to as a top seal method) is an overlap method. It has been adopted by some instead of the system. In this top seal method, the amount of film used can be reduced by half as compared with the case where the overlap method is employed.

[0005]

Conventionally, this top seal method is mainly used for packaging mushrooms such as shimeji. As a specific form, mainly, a form in which glue is applied to the side surface of the tray around the opening and the end of the film covered is adhered here, and a form in which the tray and the film larger than the plane area of the tray are bonded. There is a form in which heat welding is performed by sandwiching and applying heat together with pressure.

[0006] Of these, the form in which heat welding is performed using a mold can seal the items to be packaged in the tray, and is advantageous over the overlap method. However, conventionally, a packaging process is performed by a hard film (hard film) using a dedicated type corresponding to a tray shape and a tray size. Here, a method in which a stretch film instead of a hard film is heat-welded to the tray is conceivable, but the stretch film tends to wrinkle and may have a poor appearance after packaging as compared to the hard film. In addition, since it is necessary to carry in and carry out a stretch film which is thin and does not have a stiffness with respect to the position where heat welding is to be performed, the transport mechanism may be large.

An object of the present invention is to provide a packaging apparatus for performing packaging by thermally bonding a stretch film to a tray.
It is an object of the present invention to provide a packaging apparatus / packaging method which has a good appearance after packaging and has a compact transport mechanism.

[0008]

According to a first aspect of the present invention, there is provided a top seal type packaging apparatus, wherein an opening is covered with a stretch film in a state where an object to be packaged is accommodated in the tray with respect to a tray having an open top. This is a packaging device that melts and fuses the sheet around the opening of the tray by heat. This top seal type packaging device includes a stretch mechanism, a control unit, and a film winding unit. The stretching mechanism stretches the stretch film. The control unit controls to operate the stretching mechanism and stretch the stretch film at least before welding the stretch film to the tray. The film winding section winds up the stretched film after fusing.

In the packaging apparatus according to the present invention, the opening of the tray is covered with the stretch film, and the stretch film is welded to the periphery of the opening of the tray by heat, and the stretch film is blown off by heat. In addition, since the stretch film after the fusing is wound up, it is possible to feed the thin stretch film without any rigidity by a compact transport mechanism. That is, in the related art, the stretch film is transported while sandwiching both sides with a belt or the like, or is clamped on a chain or the like that moves in the transport direction, and is transported while being gripped. For this reason, the equipment becomes large,
There is a problem that costs also increase. In contrast,
In the packaging device according to the present invention, since the continuity of the stretch film is ensured by providing the film winding section, it is possible to transport the stretch film without gripping the thin stretch film. Thereby, the transport mechanism can be made compact.

In this case, a stretch mechanism is provided to stretch the stretch film at least before welding the stretch film to the tray. For this reason, the wrinkles of the stretch film covering the opening of the tray are increased before welding, and the appearance after packaging is improved. A top seal type packaging device according to a second aspect is the packaging device according to the first aspect, wherein the fusing position of the stretch film is outside of a welded portion with the peripheral portion of the opening of the tray.

According to a third aspect of the present invention, there is provided the top seal type packaging apparatus according to the first or second aspect, wherein the control unit operates the stretch mechanism at least after the stretch film is blown, and controls the stretch film blowout part. Apply tension to the vicinity. Here, tension is applied to the vicinity of the fusing portion after fusing the stretch film, so that fusing is complemented even when a portion that has not been completely blown off remains. In addition, if tension is applied to the stretch film even during fusing, the stretch film is easily blown.

Further, since the stretch film is stretched after the fusing, the problem that the remaining portion of the blown stretch film clings to the tray or the like can be suppressed. A top seal type packaging device according to a fourth aspect is the packaging device according to any one of the first to third aspects, and includes a film transport mechanism and a lift mechanism. The film transport mechanism transports the stretch film. The lift mechanism raises the tray and presses the tray against the stretch film transported by the film transport mechanism. In addition, the control unit operates the stretch mechanism to stretch the stretch film before the tray hits the stretch film, and controls the stretch mechanism to operate to relax the stretch of the stretch film after the tray hits the stretch film. .

Here, a state is realized in which the opening of the tray is covered with the stretch film by pressing the tray against the stretch film by the lift mechanism. Here, the stretch film is stretched before the tray hits the stretch film. For this reason, when pressed against the tray, the stretch film is in a state without wrinkles, and the tray is in a state in which the opening is covered with the stretch film without wrinkles.

Further, the stretching of the stretch film is relaxed after the tray is pressed against the stretch film. For this reason, the drawback that the stretch film is excessively stretched by the relative movement between the stretch film and the tray by the lift mechanism after the tray is pressed against the stretch film is suppressed. The top seal type packaging device according to claim 5 is the packaging device according to any one of claims 1 to 4, wherein the stretching mechanism is provided between a supply position of the stretch film and an end of the welding position. I have.

A top seal type packaging apparatus according to a sixth aspect is the packaging apparatus according to any one of the first to fifth aspects, further comprising a detecting means. This detecting means detects the opening portion of the stretch film that has been removed by fusing. Then, the control unit performs control not to operate the stretch mechanism on at least a portion including the opening portion of the stretch film detected by the detection unit.

Here, the opening portion of the stretch film removed by fusing is detected, and control is performed so that the stretch film is not stretched in the vicinity (including the portion) of the opening. In other words, for stretch films partially cut out by fusing,
Control is performed so that stretching is not performed. For this reason, even if the stretch film is partially cut out and has an increased degree of softness, problems such as meandering and entanglement can be suppressed.

A top seal type packaging device according to a seventh aspect is the packaging device according to any one of the first to sixth aspects, wherein the stretching mechanism has a plurality of film holding portions for holding the stretch film. I have. Here, since the stretch film is held by a plurality of film holding portions, the film holding portion is arranged (or moved) at a position corresponding to the tray shape, so that an appropriate stretch film corresponding to the tray shape can be obtained. Can be stretched.

According to an eighth aspect of the present invention, there is provided a top seal type packaging apparatus according to the seventh aspect, wherein the plurality of film holding sections can set different holding forces. The top seal type packaging device according to claim 9 is the packaging device according to claim 7 or 8, wherein the control unit includes a plurality of film holding units based on at least one of a characteristic of the tray and a characteristic of the stretch film. The timing of holding and canceling the holding is changed.

Here, it is possible to stretch the stretch film according to the characteristics of the tray such as the shape of the tray and the characteristics of the stretch film such as the material of the stretch film. A top seal type packaging device according to a tenth aspect is the packaging device according to any one of the first to ninth aspects, wherein the stretching mechanism includes at least one in a transport direction of the stretch film and a width direction orthogonal to the transport direction. Stretch the stretch film in the direction.

[0020] In the top seal type packaging method according to the eleventh aspect, the opening is covered with a stretch film in a state where an object to be packaged is accommodated in the tray with respect to the tray having an open upper part,
This is a method in which the stretch film is welded to the periphery of the opening of the tray by heat and cut off. This top seal type packaging method includes a film supplying step, a stretching step, and a film winding step. In the film supply step, the stretch film is transported above the tray. In the stretching step, at least before the stretch film is welded to the tray, the stretch film is stretched in a direction crossing the transport direction. In the film winding step, the stretch film after fusing is wound.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Outline of Apparatus> FIGS. 1 and 2 show a top seal type packaging apparatus according to an embodiment of the present invention. The packaging apparatus 1 shown here covers the upper opening o of the tray T containing fresh foods such as meat and fish and processed foods such as side dishes with a stretch film Fm (see FIGS. 3 and 4), and FIGS. As shown in FIG. 5, a flange (opening peripheral portion) f located around the opening o of the tray T and the stretch film Fm are sealed by heat welding.

<Structure of Apparatus> This packaging apparatus 1 includes a frame 1a, a tray mounting / holding mechanism 2 for holding a tray T, four rollers (heat bodies) 3 located above the tray mounting / holding mechanism 2, A film transport mechanism 5 for supplying the stretch film Fm between the tray mounting and holding mechanism 2 and the roller 3, a lifting mechanism 6 for raising and lowering the tray mounting and holding mechanism 2, and a roller vertical moving mechanism 7 for mainly moving the roller 3 up and down. ,
A roller rotating mechanism 8 having two rotating axes and rotating the roller 3 around each of the rotating axes 81a and 81b; a stretching mechanism 9 for stretching the stretch film Fm between the tray placing and holding mechanism 2 and the roller 3; The control unit 10 includes a control unit 10 (see FIG. 9) for performing control.

<Details of Configuration of Each Part> (Tray Placement / Holding Mechanism) The tray placement / holding mechanism 2 holds and holds the tray T on its upper surface, and is moved up and down by a lift mechanism 6. Further, the tray mounting / holding mechanism 2 can be pulled out from the position shown by the solid line in FIG. 2 to the position shown by the two-dot chain line, and can be pushed in reverse. This horizontal movement is performed manually or by driving means (not shown).

The operation of placing the tray T on the tray placing / holding mechanism 2 may be performed manually by an operator, or may be automatically transferred from a separately provided tray T transporting device. You may make it. (Roller) The roller 3 is a cylindrical member, and is rotatably supported by a roller supporting portion 71 of a roller up / down moving mechanism 7 described later. On the surface of the roller 3, a layer softer than other portions is formed in order to reduce frictional resistance with the stretch film Fm.
Specifically, the surface of the roller 3 is formed of an elastic material such as resin or synthetic rubber, and even when the surface of the flange f of the tray T has minute irregularities, the compression bonding between the stretch film Fm and the flange f can be performed. It has been secured.

As shown in FIG. 5, two rollers 3 are provided for turning shafts 81a and 81b of a roller turning mechanism 8, which will be described later. FIG. 5 is an arrangement diagram when the roller 3 is viewed from below. Thus, roller 3
Are arranged in plan view as shown in FIG. 5, and are attached to the respective pivot shafts 81a and 81b at an angle of about 110 °.

These rollers 3 are shown in FIGS.
As shown in FIG. 7, the roller T is supported by the roller support 71 in a state where it is inclined with respect to the upper surface of the tray T parallel to the horizontal plane when viewed from the side. This inclination is set such that the end of the roller 3 on the side of the rotating shafts 81a and 81b is at a position higher than the other end. The roller 3 has a roller 3 inside.
Is disposed. The specifications of this heater are the tray T to be sealed and the stretch film Fm.
Considering that it is necessary to input energy that can recover the amount of heat taken away by the seal in a short time,
Appropriate specifications have been selected.

(Film transport mechanism) Film transport mechanism 5
Is a mechanism that unwinds the stretch film Fm between the tray placing and holding mechanism 2 and the roller 3 in the lowered state, and winds up the stretch film Fm that has been partially cut out by fusing accompanying a seal. As shown in FIG. 1, the film transport mechanism 5 includes a film setting section 51.
, A film winding section 53 and a film transport section 52. The film setting section 51, the film transport section 52, and the film winding section 53 are supported by the frame 1a, respectively.

The film setting section 51 is composed of a member that rotatably supports the film roll R of the stretch film Fm, and holds the film roll R and serves as a supply source of the stretch film Fm. The film setting section 51 has a core support member 51a that can move up and down and a support roller 51b that supports the film roll R obliquely below. The film roll R is supported by the core support member 51a and the support roller 51b, and a feeding roller 52a of a film transport unit 52 described later (see FIG. 1).

The film take-up section 53 is provided to take up the remaining stretch film Fm, part of which is taken out by packaging (top seal) of the tray T, and has a take-up shaft 53a. This winding shaft 5
3a is rotated by a belt 53b hung on a motor 52c described later. The detailed structure of the winding shaft 53a will be described later.

The film transport section 52 includes a feeding roller 5
2a, a motor 52c for rotating the feeding roller 52a via a belt 52b, and a film supporting roller 52a.
d. The stretch film Fm drawn from the film roll R is sent to the film winding unit 53 side by the rotation of the feeding roller 52a. In addition, the take-up shaft 53a rotates together with the pay-out roller 52a with the rotation of the motor 52c, so that the stretch film Fm is taken up by the take-up shaft 53a while being fed from the film roll R. The rotation speed of the winding shaft 53a is set to be higher than the rotation speed of the feeding roller 52a. For this reason,
The stretch film Fm is in a state where a tension is applied along the transport direction. As a result, transport without slack is performed.

The feeding roller 52a has a gripping property with respect to the stretch film Fm, and can feed the stretch film Fm by a predetermined amount while suppressing a slip. More specifically, a one-way clutch (not shown) is provided to apply a mirror finish to the surface of the feeding roller 52a to prevent the feeding roller 52a from rotating in the reverse direction. As shown in FIG. 1, the feeding roller 52a
The support roller 51b is arranged symmetrically with respect to the support roller 51b. The distance between the feeding roller 52a and the supporting roller 51b is set smaller than the diameter of the core material of the film roll R, so that the film roll R does not fall off between the rollers 52a and 51b. I have.

The film supporting roller 52d is arranged near the film winding section 53, and is set so that the upper surface of the film supporting roller 52d coincides with the lower surface of the feeding roller 52a (see FIG. 1). Therefore, the horizontal state of the portion of the stretch film Fm being transported, which is located between the feed roller 52a and the film support roller 52d, is maintained.

(Stretch Mechanism) The stretch mechanism 9
Of the stretch film Fm continuing from the film setting section 51 to the film winding section 53, the feeding roller 5
This is a mechanism that grips both side ends of a horizontal portion between the film support roller 2a and the film support roller 52d and stretches the stretch film Fm in the width direction (the left-right direction in FIG. 2). The stretch mechanism 9 includes a pair of film grippers 91a and 91b extending in the film transport direction, and a stretch drive unit 93 (see FIG. 9) for moving these in a direction perpendicular to the film transport direction (left-right direction in FIG. 2). have.

The film holding portions 91a and 91b hold the stretch film Fm by sandwiching the stretch film Fm from both upper and lower sides, and are turned ON / OFF using solenoids 92a and 92b (see FIG. 9). In addition, rubber (or resin) pads p1 to p8 having a large coefficient of friction are attached to portions that come into contact with the stretch film Fm from above to prevent slippage between the film gripping portions 91a and 91b and the stretch film Fm. are doing. That is, when the gripping structure is specifically described, the film gripping portions 91a and 91b
Has a structure in which the stretch film Fm is sandwiched and held between the pads p1 to p8 and the lower member 94.

The stretch driving section 93 includes a motor 93a.
(See FIG. 9), and is composed of a guide rail, a sprocket, a chain, and the like, and moves the film grippers 91a and 91b in the left and right directions in FIG. (Lift Mechanism) The lift mechanism 6 is a mechanism for pushing up the tray mounting and holding mechanism 2 holding the tray T with respect to the stretch film Fm as shown in FIG. The lift mechanism 6 includes a driving motor 61, a large gear 62 pivotally supported by the frame 1a, a link member 63, a lever 64 having one end pivotally supported by the frame 1a at a fulcrum 64a, and a tip end of the lever 64 rotatably. It is composed of a mounted disk member 65 and the like.

When the drive motor 61 operates, the large gear 62 rotates via a gear fixed to the motor shaft. Then, the lever 64 is moved to the fulcrum 64a via the link member 63.
Around the center. Thereby, the tray mounting and holding mechanism 2 whose lower surface is supported by the disk member 65 moves up and down (see FIGS. 2 and 3). In addition, the tray mounting and holding mechanism 2
Is guided by a vertical guide rail 69,
It moves in the vertical direction by the operation of the lift mechanism 6.

(Roller Up / Down Moving Mechanism) The roller up / down moving mechanism 7 is a mechanism for changing the height position of the roller 3, and as shown in FIG. A link mechanism 72, a pressing plate 73, a lever mechanism 74 for applying a force to the pressing plate 73 from above, and a motor 75 for operating the lever mechanism 74 are provided.

The roller supporting portion 71 supports the roller 3 so that the roller 3 is inclined as shown in FIGS. 1 and 2 in a side view. 1 and 2 in the roller 3 shown in FIGS.
The dotted line is the rotation axis of the roller 3. Link mechanism 72
One end supports the roller supporting portion 71 with a pin, and the other end is pressed down by the pressing plate 73. When the other end of the link mechanism 72 is pressed down by the pressing plate 73, one end is raised as shown in FIGS. 1 and 2, and the roller support 71 and the roller 3 are also raised. Become. On the other hand, the holding plate 73 is
When no force is applied to the roller 3, the roller support 71 and the roller 3
The other end of the link mechanism 72 is lowered by its own weight or the like (see FIGS. 2 and 4).

A force is applied to the pressing plate 73 from above by a lever mechanism 74 operated by a motor 75. As shown in FIGS. 2 and 4, the outer peripheral portion of the pressing plate 73 is in a state of being placed on a rolling element that is supported at the other end of the link mechanism 72. (Roller turning mechanism) The roller turning mechanism 8 is a mechanism that turns the roller 3 and the roller supporting portion 71 and the link mechanism 72 that support the roller 3 by a predetermined angle during seal packaging. The roller turning mechanism 8 mainly includes a first turning shaft 81a,
It comprises a second turning shaft 81b and a motor 82 for rotating both turning shafts 81a and 81b.

The lower end of the first turning shaft 81a is fixed to a base member 79 which supports two link mechanisms 72, and the upper end thereof is meshed with the main gear 83 via a gear. The main gear 83 is connected to the motor 82 by a pulley and a belt 84, and is rotated by the operation of the motor 82. The lower end of the second turning shaft 81b is fixed to a base member 79 supporting another two link mechanisms 72 (a member different from the base member 79 to which the first turning shaft 81a is fixed). The upper end of the second turning shaft 81b is meshed with the main gear 83 via a gear (see FIG. 5).

When the motor 82 rotates the turning shafts 81a and 81b by a predetermined angle under the control of the control unit 10, each roller 3 turns by a predetermined angle about the first turning shaft 81a or the second turning shaft 81b. (See FIG. 6).
In FIG. 6, for easy understanding, the roller 3 connected to the first turning shaft 81a is connected to the rollers 3a and 3b.
And the rollers 3 connected to the second turning shaft 81b are indicated as rollers 3c and 3d. In FIG. 6,
The position of the roller 3 before turning is shown by a solid line, and the position of the roller 3 after turning is shown by a dotted line.

(Control Unit) As shown in FIG.
Is equipped with a CPU 11 as a control unit main body,
A ROM 12 and a RAM 13 are mounted as a main storage unit controlled by the CPU 11. Further, the control unit 10
It has a display control circuit 15a for controlling data display on a display 15 for displaying to an operator, a keyboard circuit 16a for taking in key input data from a keyboard 16 for receiving input from the operator, and the like.

The controller 10 has a tray master file 14a in the HDD (hard disk) 14. The tray master file 14a stores data such as tray size, tray material, tray shape, and the like for each tray number. On the other hand, a data area for storing the tray information called from the tray master file 14a is formed in the RAM 13.

Then, CPU 11, ROM 12, RAM
The HDD 13 and the circuits 15a and 16a are interconnected via bus lines such as an address bus and a data bus. This control unit 10, as shown in FIG.
It is connected to driving means such as a motor of each mechanism and the heater 31, and controls these movements.

<Operation Control of Packaging Apparatus> (Overall Control) When the tray T containing packages such as foods is placed on the tray placing and holding mechanism 2 which is drawn out to the position shown by the two-dot chain line in FIG. The tray mounting / holding mechanism 2 is horizontally moved below the rollers 3 by manual operation or by driving means (not shown).

The tray mounting / holding mechanism 2 which has moved below the roller 3 positions the tray T by pressing the side surface of the tray T with a plurality of holding members, and holds the tray T so as to prevent the tray T from being displaced. I do. The control unit 10 calculates an amount of feeding the stretch film Fm by the film transport mechanism 5 according to the tray. More specifically, the control unit 10 calls out a tray size, a tray material, and the like stored in the tray master file 14a from a tray number input from the keyboard 16, and calculates a feeding amount of the stretch film Fm. The determination of the feeding amount of the stretch film Fm, that is, the determination of the film transport amount will be described later in detail.

When the stretch film Fm is fed out from the film transport mechanism 5, the control section 10 operates the stretch mechanism 9 to stretch the stretch film Fm in the width direction (the left-right direction in FIG. 2). Thereby, tension is applied to the stretch film Fm in the width direction, and the stretch film Fm is in a state without wrinkles. Next, the control unit 10 operates the lift mechanism 6 to lift the tray placing and holding mechanism 2 holding the tray T. According to this, the tray T becomes the stretch film F
m and then stop (see FIG. 3).

Next, the control unit 10 controls the motor 75 to release the downward urging of the pressing plate 73 by the lever mechanism 74, and opens the link mechanism 72. Then, the roller 3 descends until it comes into contact with the tray T by its own weight or the like (see FIG. 4). Since these rollers 3 are independent from each other, each roller 3 comes into contact with the tray T with substantially the same pressure.

Next, the controller 10 controls the motor 82 to rotate the turning shafts 81a and 81b by a predetermined angle. The predetermined angle is set to 110 ° here so that the entire flange f of the tray T is sealed by any of the rollers 3a to 3d (see FIG. 6). Pivot shaft 81a,
When the roller 3 rolls on the tray T from above the stretch film Fm by rotating around the center 81b, the roller 3 thermally welds the flange f of the tray T and the stretch film Fm.

FIG. 7 shows an enlarged view of the vicinity of the contact portion between the rollers 3 when the roller 3 moves along the periphery of the tray T. The tray T is in a state where the opening o is covered with the stretch film Fm. The stretch film Fm is pressed against the flange f of the tray T. Then, the roller 3 hits the contact portion between the stretch film Fm and the flange f obliquely from above to apply heat and force. By these heat and force, the stretch film F
m and the flange f are thermally welded. At this time, heat and force concentrate on the stretch film Fm at the edge portion of the tray T (here, the outer portion of the top of the flange f on which the roller 3 is in contact), so that the stretch film Fm is at the edge portion of the tray T. Is melted and separated (see FIG. 8). The control unit 10 rotates the roller 3 at such a speed that the stretch film Fm and the flange f are thermally welded and the stretch film Fm is blown off outside the joint portion by the thermal welding.

After the sealing of the stretch film Fm on the tray T by the roller 3 is completed, the roller 3 is pulled up and the tray T is lowered, and then the tray T sealed and packaged is taken out from the drawn tray mounting and holding mechanism 2. Then, move to the next cycle. At the time of moving to the next cycle, the stretch film Fm partially cut out by heat fusing by the seal packaging of the tray T is wound around the winding shaft 53a. At this time, the rotation of the motor 52c rotates the film supporting roller 52d and the feeding roller 52a, so that the winding of the stretch film Fm for the next cycle (supply of the stretch film Fm below the roller 3) is performed simultaneously with the winding. Will be

The width of the stretch film Fm is set so as to be wider than the width of the tray T at least when stretched by the stretching mechanism 9.
The continuity of the stretch film Fm is not broken by the seal wrapping of the tray T (pulling out of the stretch film Fm), and the trouble that the film winding unit 53 cannot take up the film does not occur.

(Control of Stretch Mechanism) The control unit 10
While the stretch film Fm is being transported by the film transport mechanism 5, the stretch mechanism 9 is not operated, and the stretch mechanism 9 is operated when the stretch film Fm is welded to the tray T. When the stretch film Fm is welded to the tray T, the control unit 10 operates the stretch mechanism 9 in four stages. The control of the stretching mechanism 9 will be described with reference to FIGS.

First, as a first step, both sides of the stretch film Fm are gripped by the film grippers 91a and 91b at the home position (HP) as shown in FIG. 10 (a). The stretch film Fm is stretched by moving the film holding portions 91a and 91b outward as shown in FIG. That is, before the tray T is pushed up to the stretch film Fm by the lift mechanism 6,
The stretching mechanism 9 is operated to stretch the stretch film Fm in advance. Stretch film Fm at this time
Is referred to as a pre-stretch amount, and the determination of the pre-stretch amount will be described in detail later.

Next, as a second step, when the tray T is lifted by the lift mechanism 6, immediately after the tray T is pressed against the stretch film Fm, the stretching mechanism 9 is operated to loosen the stretching of the stretch film Fm.
That is, between the time when the tray T starts to contact the stretch film Fm as shown in FIG. 10C and the time when the tray T is completely lifted as shown in FIG. To relax the tension of the stretch film Fm. However, FIG.
Even when the tray T is fully raised, the stretch film Fm is kept in a state where a certain amount of tension is applied.

Next, as a third stage, after the stretch film Fm is welded to the tray T by the roller 3 as shown in FIG.
1b is moved outward to stretch the stretch film Fm. Then, as a fourth step, after the welding of the stretch film Fm to the tray T and the melting of the stretch film Fm are completed, the roller 3 is pulled up and the tray T is lowered, and then both the film holding portions 91a,
Return 91b to the home position.

<Features of the Packaging Apparatus of the Present Embodiment> (1) In the packaging apparatus 1 of the present invention, since the stretching mechanism 9 is provided, the wrinkles of the stretch film Fm covering the opening o of the tray T are extended. And the appearance after packaging is improved.

Further, in the packaging apparatus 1, the operation of the stretching mechanism 9 is limited to a series of operations for welding the stretch film Fm to the tray T. That is, the stretch mechanism 9 is not operated during the transport of the stretch film Fm by the film transport mechanism 5. For this reason, even in the case of the stretch film Fm which is thin and has no stiffness, almost no trouble occurs in the conveyance such as meandering.

(2) In the packaging device 1, the stretch film Fm is stretched before the tray T is pressed against the stretch film Fm by the lift mechanism 6 (FIG. 10).
(B)). Therefore, when the stretch film Fm is pressed against the tray T, the stretch film Fm is in a state without wrinkles, and the opening o of the tray T is covered with the stretch film Fm without wrinkles.

(3) In the packaging apparatus 1, the stretching mechanism F is controlled so that the stretching of the stretch film Fm is relaxed after the tray T is pressed against the stretch film Fm by the lift mechanism 6 (see FIG. 11D). Therefore, the stretch film Fm is not excessively stretched by the lifting of the tray T by the lift mechanism 6 against which the tray T is pressed against the stretch film Fm. Thereby, problems such as generation of pinholes, breakage of the bag, and poor welding, which may be caused by excessively stretching the stretch film Fm, can be suppressed. In addition, such control makes it possible to seal a tray having a small strength while suppressing deformation.

(4) In the packaging apparatus 1, even when the stretch film Fm is welded to the tray T, the outside of the welded portion of the stretch film Fm is kept in tension (FIG. 11D). , (E))
Therefore, the stretch film Fm is easily blown outside the portion of the stretch film Fm welded to the tray T.

(5) Further, in the packaging device 1, the rollers 3
After the stretch film Fm is welded to the tray T, the stretch film Fm is stretched again. Therefore, the problem that the remaining portion of the blown stretch film Fm is not attached to the tray T or the tray mounting and holding mechanism 2 is suppressed. Even when the fusing is not complete, the fusing is complemented by the stretching of the stretch film Fm.

(6) Conventionally, a stretch film is transported while sandwiching both sides with a belt or the like, or is clamped on a chain or the like that moves in the transport direction, and is transported while being gripped. . However, such a transport method requires a large-scale apparatus and increases costs.

In view of this, the packaging apparatus 1 of the present embodiment adopts a configuration in which the stretch film Fm unwound from the film roll R is wound around the winding shaft 53a of the film winding section 53, and is transported while being gripped. However, the film transport mechanism 5 and the gripping mechanism (the film gripping portions 91a and 91b of the stretch mechanism 9) are completely separated. This makes the device 1 compact and occupies less space.

<Detailed Structure of Winding Shaft> Since the stretch film Fm is rich in elasticity and has self-adhesiveness, if a simple tubular member is used as the winding shaft, the stretched film Fm is wound up. It becomes difficult to remove from the shaft. On the other hand, it is conceivable to use a paper tube or the like as the winding shaft, but it is desirable to separate only the wound stretch film Fm for disposal or recycling.

In view of this, in the packaging apparatus 1 of the present embodiment, the winding shaft 53a is configured as shown in FIG. The winding shaft 53a includes a support shaft 41,
Fixing plate 42, take-up guide 43, guide plate 44, guide pulley 45, detachable guide 46
, A rubber belt 47, and a torque pulley 48.

The plurality of winding guides 43 are swingably supported by the fixed plate 42. Guide plate 4
4 is formed with a long hole in the radial direction through which the winding guide 43 passes. That is, the guide plate 44 allows the winding guide 43 to swing. Guide plate 4
In the vicinity of 4, a rubber belt 47 for urging the winding guide 43 inward is arranged. The guide pulley 45 plays a role in adjusting the amount of indentation inside the tip (the left end in FIG. 12) of the winding guide 43 (see FIG. 12B).

The detachable guide 46 includes a disk portion 46a that contacts the tip of the winding guide 43, and a guide portion 46 that extends from one surface of the disk portion 46a and enters the inside of the winding guide 43.
b. The tip of the guide portion 46b (FIG. 1)
A taper whose diameter gradually decreases is formed in the portion (right side of 2). In the state set as shown in FIG. 12A, the attachment / detachment guide 46 supports the inner portion of the leading end of the winding guide 43 and holds the winding guides 43 in a parallel state. A belt 53b is hung on the torque pulley 48.

When removing the film waste Fm1 wound on the winding shaft 53a having the above-described structure, the detachment guide 46 is removed as shown in FIG.
Then, since the leading end of the winding guide 43 is deflated, a gap is generated between the inner peripheral surface Fm1a of the film waste Fm1 that has been in close contact with the winding guide 43 and the winding guide 43. As a result, the film waste Fm1 can be easily extracted.

<Determination of Prestretching Amount etc.>
The stretch amount (pre-stretch amount) of the pre-stretch for stretching the stretch film Fm before the tray T is pushed up against the stretch film Fm is determined based on the following parameters. These parameters are obtained from the tray master file 14a based on the input tray number and the like.
Can be obtained by retrieving the tray size, tray material, and the like stored in the. (A) Size of tray T (b) Width dimension of film roll R (c) Material of stretch film Fm (d) Material of tray T (e) Shape of tray T (f) Ambient temperature The above parameters (a), According to (b), it is possible to determine the optimal pre-stretch amount from the relative relationship between the width of the stretch film Fm and the width of the tray T.

With the parameter (c), it is possible to determine the pre-stretch amount in consideration of characteristics based on the material such as easy tearing. The parameter (d) makes it possible to suppress the crushing phenomenon of the tray T caused by the insufficient strength of the tray T. With the parameter (e), it is possible to suppress the problem that the film is broken due to the shape of the edge of the tray T or the like.

The parameter (f) makes it possible to determine the pre-stretch amount in consideration of the difference in the hardness of the tray T due to the temperature. Further, not only the pre-stretch amount, but also the film gripping portions 91a, 91 when the tray T is pushed up.
The return timing for moving 1b inward and the return amount are also determined using the above parameters.

<Determination of Film Transport Amount> After the packaging start signal is input and the size of the tray T to be packaged is determined, the film transport operation is performed. The following methods (M1) and (M1)
2) can be considered. (M1) Compare the amount of film transported after the previous packaging is completed (the same amount as the amount required for the wrapped tray) with the amount of film transported for the current tray, and calculate the amount to make up for the shortfall. Transport.

(M2) The amount of film conveyed (taken up) after the previous packaging is completed is kept to the minimum conveyed amount,
Before packing the trays this time, transport the amount to make up the shortage. According to the method (M1), in the case of a tray requiring the same transport amount as the previous time or a tray requiring a smaller transport amount than the previous time, no shortage occurs and the film is not transported. Then, the film is conveyed for the shortage only when a convey amount larger than the last time is required. That is, if the tray size is equal to or smaller than the previous tray size, packaging can be performed without film transport. However, when the tray is switched to a tray that requires a small amount of transport, an excess amount of transport is generated. Therefore, when the film transport amount is frequently switched in, for example, high-mix low-volume production, film waste increases.

On the other hand, the method (M2) can eliminate such film waste. From such considerations, in the packaging device 1 of the present embodiment, the method (M2) is adopted. (M1), (M2)
Either method does not affect the packaging ability because the timing of film transport performed after the previous packaging is completed overlaps with other operations such as the operation of discharging the completed tray.

<Film Exchange> A film exchange operation when the stretch film Fm runs out of the film roll R will be described below. First, as shown in FIG. 13, the seal unit including the roller up / down moving mechanism 7, the roller turning mechanism 8, the roller 3, and the like is opened.

Next, take-up shaft 5 from film roller R
The stretch film Fm connected to 3a is cut in the middle, and the film roll R is removed. When the film residue Fm1 wound around the winding shaft 53a is large, as described above, the detachment guide 46
To remove the film residue Fm1 (see FIG. 12).

Next, a new film roll R is set, and the feeding roller 52a and the film supporting roller 52 are set.
and d is wound around the winding shaft 53a. And
The seal unit is closed, and the stretch film Fm is fed twice or three times to complete the film exchange operation. [Other Embodiments] (A) In the above embodiment, in order to make the apparatus 1 compact, a transport mechanism and a gripping mechanism are used instead of a conventional transport method in which a stretch film is transported while being gripped by a clamp or the like. A completely separate device configuration is adopted.

However, the present invention can also be applied to an apparatus adopting a conventional transport system in which a stretch film is gripped and transported. However, since the stretch film Fm partly cut out by the seal must be conveyed to be wound up, it is necessary to control as follows. That is, the stretch film Fm extends from the film roller R to above the tray placing / holding mechanism 2.
Is not cut out, the stretch film Fm can be conveyed while being tensioned while being gripped. However, the cut-out conveyance path (from above the tray mounting and holding mechanism 2 to the film winding unit) In the transport path up to 53), applying tension to the stretch film Fm is strictly prohibited. This is because if the cut-out stretch film Fm is conveyed with tension, there is a high possibility that the cut-out stretch film Fm may meander, be caught in the conveying member, or be torn off. Therefore, it is necessary to control the stretch film Fm so that the tension is not applied to the stretched film Fm at least in the transport path after the cutout.

Specifically, first, during the transport of the stretch film Fm from at least above the tray T (above the tray mounting and holding mechanism 2) to the film winding section 53, the tension is not applied to the stretch film Fm. It is conceivable to control. Further, a detecting means for detecting an opening portion of the stretch film Fm cut out by fusing is provided, and control is performed so that tension is not applied to at least a portion near the opening portion of the stretch film Fm detected by the detecting means. A method of doing so is also conceivable.

With this control, tension is not applied to the stretch film Fm partly cut out by fusing, so that even the stretch film Fm partly cut out and having an increased degree of softness has a meandering shape. Problems such as entanglement and entanglement are suppressed. (B) In the above embodiment, the left and right film grip portions 91a, 91b in FIG.
ON / OFF is switched. That is, each of the film holding portions 91a and 91b is connected to the pad p1.
~ P8 and the lower member 94 can be controlled only in a state where the stretch film Fm is sandwiched or in a state in which the stretch film Fm is released.

However, if the gripping state and the gripping release state can be changed at each position in the transport direction of the stretch film Fm according to the shape of the tray, it is possible to perform control that enables more stable packaging. Then, if there is room for cost, the packaging device 1 of the above embodiment can be improved as follows.

Here, a solenoid is prepared for each of the pads p1 to p8 so that the control unit 10 can control a total of 16 solenoids. This makes it possible to hold and stretch (stretch) the stretch film Fm that matches the tray shape and tray size. Further, the above parameters (a) to (f)
If the ON / OFF timing of each solenoid is controlled based on the above, more appropriate packaging can be performed.

If the pads p1 to p8 can be moved in a plane, or if the pads p1 to p8 are arranged at positions corresponding to a frequently used tray shape, more stable packaging processing can be performed. For example, it is conceivable to dispose the gripping means such as the pad p1 and the pad p8 at both ends in the film transport direction while shifting inward. Further, each of the pads p1 to p1
If the holding force can be adjusted by holding the stretch film Fm by p8 using a torque motor instead of a solenoid, more precise packaging control can be performed.

(C) In the above embodiment, tension is applied to the stretch film Fm by stretching the stretch film Fm by the stretch mechanism 9 in the direction perpendicular to the transport direction of the stretch film Fm (the left-right direction in FIG. 2). Alternatively, or additionally, the packaging device 1 can be improved so that the stretch film Fm can be stretched in the transport direction of the stretch film Fm. For example, if the film winding unit 53 is modified so as to move in a predetermined range in the transport direction of the stretch film Fm, the tension of the stretch film Fm mainly along the transport direction can be more finely controlled.

(D) In the above embodiment, the keyboard 16
The pre-stretch amount is determined by calling the tray size and tray material stored in the tray master file 14a from the tray number and the like input from the
Each information in the tray master file 14a is called from the tray shape recognized from the image processing result of the tray T captured by the imaging means such as the D camera, or the width of the tray T is detected by scanning the width direction of the tray T with the sensor. At the same time, when the tray T is carried in, each information in the tray master file 14a can be called out by detecting the depth dimension of the tray T.

In this case, the tray size detecting means such as a CCD camera and a sensor can be disposed obliquely above the tray mounting and holding mechanism 2 which is drawn out to a position indicated by a two-dot chain line in FIG. (E) In the above embodiment, the feed roller 52a and the take-up shaft 53a are rotated by the operation of the drive motor 52c, but if the film support roller 52d is further rotated by the drive motor 52c, the stretch film Fm Can be expected to be more stable.

(F) In FIG. 2 and the like of the above embodiment,
Before the stretching, the width of the stretch film Fm is larger than the width of the tray T. However, even when the width of the stretch film Fm is smaller than the width of the tray T, the stretch film Fm is stretched in the width direction. If the width of the stretch film Fm is larger than the width of the tray T in the state, the continuity of the stretch film Fm is not interrupted even by welding to the tray T, and the conveyance to the film winding unit 53 is not hindered. Absent.

Also, from the viewpoint of resource saving, a stretch film Fm (film roll R) having a small width is positively used to reduce the amount of pre-stretching (stretching amount) for a small tray T and to reduce the amount of pre-stretching for a large tray T The amount of stretching can be greatly controlled. In this case, there is also a secondary effect that one kind of narrow stretch film Fm can handle from a small tray T to a large tray T.

(G) In the above embodiment, the roller 3 is brought into contact with the tray T from above the stretch film Fm and is swung to scan the entire flange f of the tray T. The present invention is also applicable to a packaging apparatus employing a method in which the tray T is pressed against the elastic heating sheet from below.

Further, it is also possible to apply a laser beam to the flange f of the tray T and move the laser beam along the flange f so that welding and fusing can be performed in a non-contact manner.

[0092]

According to the present invention, since the stretch film after the fusing is wound up, it is possible to feed the thin stretch film without any rigidity by a compact transport mechanism. In addition, since the stretch mechanism is provided to stretch the stretch film at least before welding the stretch film to the tray, wrinkles of the stretch film covering the opening of the tray are stretched before welding, and the appearance after packaging is improved. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a packaging device according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the packaging device.

FIG. 3 is a diagram showing the operation of the packaging device.

FIG. 4 is a diagram showing the operation of the packaging device.

FIG. 5 is a plan view of a roller.

FIG. 6 is a diagram illustrating a plane trajectory obtained by turning a roller.

FIG. 7 is an enlarged view of the vicinity of the flange of the tray at the time of contact with a roller.

FIG. 8 is an enlarged view of the vicinity of the flange of the tray at the time of film thermal welding.

FIG. 9 is a control block diagram of the packaging device.

FIG. 10 is an operation diagram of a stretching mechanism.

FIG. 11 is an operation diagram of a stretching mechanism.

FIG. 12 is a view showing the configuration and use of a winding shaft.

FIG. 13 is a diagram illustrating an open state of a seal unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Packaging device 3 Roller 5 Film transport mechanism 6 Lift mechanism 9 Stretch mechanism 10 Control part 51 Film setting part 52 Film transport part 53 Film winding part 91a, 91b Film holding part (film holding part) p1-p8 Pad (film holding part) ) T Tray f Flange (Around the tray opening) Fm Stretch film

Continued on the front page F term (reference) 3E049 AA02 AB03 CA10 DB02 EA02 EB03 EC02 FA06 FA07 3E094 AA04 CA10 CA15 DA02 FA13 FA30 GA11 HA08 HA10

Claims (11)

[Claims] 1. An opening is covered with a stretch film in a state in which an article to be packaged is accommodated in the tray having an upper opening, and the stretch film is welded to a portion around the opening of the tray by heat. A top seal type packaging device for fusing, a stretch mechanism for stretching the stretch film, and a control unit for controlling the stretch mechanism to operate and stretch the stretch film at least before welding the stretch film to the tray. A top seal type packaging device, comprising: a film winding section for winding the stretch film after fusing. 2. The top-sealing type packaging apparatus according to claim 1, wherein the fusing position of the stretch film is outside a welding portion of the stretch film with a peripheral portion of the opening of the tray. 3. The top-sealing type packaging apparatus according to claim 1, wherein the control section operates the stretch mechanism to apply tension to the vicinity of the fusing portion of the stretch film at least after the fusing of the stretch film. 4. The control unit further comprises: a film transport mechanism that transports the stretch film; and a lift mechanism that raises the tray and presses the tray against the stretch film transported by the film transport mechanism. Operate the stretch mechanism to stretch the stretch film before the tray hits the stretch film, and operate the stretch mechanism after the tray presses the stretch film to stretch the stretch film. The top seal type packaging device according to any one of claims 1 to 3, which performs a loosening control. 5. The top seal type packaging apparatus according to claim 1, wherein the stretching mechanism is provided between a position where the stretch film is supplied and an end of the welding position. 6. A stretch detecting device for detecting an opening portion of the stretch film removed by the fusing, wherein the control unit includes at least a portion near the opening portion of the stretch film detected by the detecting device. The top seal type packaging device according to any one of claims 1 to 5, wherein control for not operating the stretch mechanism is performed. 7. The stretch mechanism has a plurality of film holding portions for holding the stretch film,
The top seal type packaging device according to any one of claims 1 to 6. 8. The top-sealing type packaging apparatus according to claim 7, wherein the plurality of film holding portions can set different holding forces. 9. The control unit according to claim 7, wherein the control unit changes the timing of holding and releasing the holding of the plurality of film holding units based on at least one of characteristics of the tray and characteristics of the stretch film. The top seal type packaging device as described in the above. 10. The top seal type according to claim 1, wherein the stretch mechanism stretches the stretch film in at least one direction of a direction in which the stretch film is transported and a width direction orthogonal to the transport direction. Packaging equipment. 11. An opening is covered with a stretch film in a state in which an object to be packaged is accommodated in the tray with the upper part opened, and the stretch film is welded to a portion around the opening of the tray by heat. A top seal type packaging method for fusing, comprising: a film supply step of transporting the stretch film above the tray; and a direction intersecting the stretch direction at least before welding the stretch film to the tray. And a film winding step of winding the stretch film after fusing.